TY - JOUR
A1 - Greiser, Sebastian
A1 - Gluth, Gregor
A1 - Sturm, Patrick
A1 - Jäger, Christian
T1 - 29Si{27Al}, 27Al{29Si} and 27Al{1H} double-resonance NMR spectroscopy study of cementitious sodium aluminosilicate gels (geopolymers) and gel-zeolite composites
N2 - The influence of starting materials and synthesis route on the properties and the structure of cementitious sodium aluminosilicate gels is not fully understood, partly due their amorphous nature and the fact that they often contain residual reactants, which can make the results of single-pulse NMR spectroscopy applied to these materials difficult to interpret or ambiguous. To overcome some of these limitations, 29Si{27Al} TRAPDOR NMR as well as 27Al{29Si} and 27Al{1H} REDOR NMR spectroscopy were applied to materials synthesized by the one-part alkali-activation route from three different amorphous silica starting materials, including rice husk ash. The latter led to formation of a fully amorphous sodium aluminosilicate gel (geopolymer), while the materials produced from the other silicas contained amorphous phase and crystalline zeolites. Application of the double-resonance NMR methods allowed to identify hydrous alumina gel domains in the rice husk ash-based material as well as significantly differing amounts of residual silica in the three cured materials. Four-coordinated Al existed not only in the aluminosilicate gel framework but also in a water-rich chemical environment with only a small amount of Si in proximity, likely in the alumina gel or possibly present as extra-framework Al in the aluminosilicate gel. The results demonstrate how the employment of different silica starting materials determines the phase assemblage of one-part alkali-activated materials, which in turn influences their engineering properties such as the resistance against chemically/biologically aggressive media.
KW - Alkali-activated materials
KW - Solid-state NMR
KW - Aluminium hydroxide
KW - Rice husk ash
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469353
DO - https://doi.org/10.1039/C8RA09246J
SN - 2046-2069
VL - 8
IS - 70
SP - 40164
EP - 40171
PB - Royal Society of Chemistry (RSC)
CY - London
AN - OPUS4-46935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gluth, Gregor
A1 - Hlavacek, Petr
A1 - Reinemann, Steffi
A1 - Ebell, Gino
A1 - Mietz, Jürgen
ED - Alexander, M.G.
ED - Beushausen, H.
ED - Dehn, F.
ED - Moyo, P.
T1 - Leaching, carbonation and chloride ingress in reinforced alkali-activated fly ash mortars
N2 - Alkali-activated fly ash mortars were studied with regard to durability-relevant transport coefficients and the electrochemical behaviour of embedded carbon steel bars on exposure of the mortars to leaching, carbonation and chloride penetration environments. The transport coefficients differed considerably between different formulations, being lowest for a mortar with BFS addition, but still acceptable for one of the purely fly ash-based mortars. Leaching over a period of ~300 days in de-ionized water did not lead to observable corrosion of the embedded steel, as shown by the electrochemical data and visual inspection of the steel. Exposure to 100 % CO2 atmosphere caused steel depassivation within approx. two weeks; in addition, indications of a deterioration of the mortar were observed. The results are discussed in the context of the different reaction products expected in high- and low-Ca alkali-activated binders, and the alterations caused by leaching and carbonation.
T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018)
CY - Cape Town, South Africa
DA - 19.11.2018
KW - Alkali-activated materials
KW - Steel corrosion
KW - Leaching
KW - Carbonation
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464381
DO - https://doi.org/10.1051/matecconf/201819902025
VL - 199
SP - Article Number 02025
PB - EDP Sciences
AN - OPUS4-46438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rauwolf, M.
A1 - Turyanskaya, A.
A1 - Roschger, A.
A1 - Prost, J.
A1 - Simon, R.
A1 - Scharf, O.
A1 - Radtke, Martin
A1 - Schoonjans, Tom
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Klaushofer, K.
A1 - Wobrauschek, P.
A1 - Hofstaetter, J. G.
A1 - Roschger, P.
A1 - Streli, C.
T1 - Synchrotron radiation micro X-ray fluorescence spectroscopy of thin structures in bone samples: comparison of confocal and color X-ray camera setups
N2 - In the quest for finding the ideal synchrotron-radiation-induced imaging method for the investigation of trace element distributions in human bone samples, experiments were performed using both a scanning confocal synchrotron radiation micro X-ray fluorescence (SR-mXRF) (FLUO beamline at ANKA) setup and a full-field color X-ray camera (BAMline at BESSY-II) setup. As zinc is a trace element of special interest in bone, the setups were optimized for its detection. The setups were compared with respect to count rate, required measurement time and spatial resolution. It was demonstrated that the ideal method depends on the element of interest. Although for Ca (a major constituent of the bone with a low energy of 3.69 keV for its K alpha XRF line) the color X-ray camera provided a higher resolution in the plane, for Zn (a trace element in bone) only the confocal SR-µXRF setup was able to sufficiently image the distribution.
KW - Synchrotron
KW - BAMline
KW - BESSY
KW - XRF
KW - X-ray Color Camera
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391944
DO - https://doi.org/10.1107/S1600577516017057
SN - 1600-5775
VL - 24
SP - 307
EP - 311
PB - International Union of Crystallography
AN - OPUS4-39194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Grengg, C.
A1 - Ukrainczyk, N.
A1 - Mittermayr, F.
A1 - Dietzel, M.
T1 - Acid resistance of alkali-activated materials: Recent advances and research needs
N2 - Cementitious materials are frequently applied in environments in which they are exposed to acid attack, e.g., in sewer systems, biogas plants, and agricultural/food-related industries. Alkali-activated materials (AAMs) have repeatedly been shown to exhibit a remarkably high resistance against attack by organic and inorganic acids and, thus, are promising candidates for the construction and the repair of acid-exposed structures. However, the reaction mechanisms and processes affecting the acid resistance of AAMs have just recently begun to be understood in more detail. The present contribution synthesises these advances and outlines potentially fruitful avenues of research. The interaction between AAMs and acids proceeds in a multistep process wherein different aspects of deterioration extend to different depths, complicating the overall determination of acid resistance. Partly due to this indistinct definition of the ‘depth of corrosion’, the effects of the composition of AAMs on their acid resistance cannot be unambiguously identified to date. Important parallels exist between the deterioration of low-Ca AAMs and the weathering/corrosion of minerals and glasses (dissolution-reprecipitation mechanism). Additional research requirements relate to the deterioration mechanism of high-Ca AAMs; how the character of the corroded layer influences the rate of deterioration; the effects of shrinkage and the bond between AAMs and substrates.
KW - Alkali-activated materials
KW - Acid attack
KW - Acid resistance
KW - Concrete repair
KW - MIC
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557376
DO - https://doi.org/10.21809/rilemtechlett.2022.157
SN - 2518-0231
VL - 7
SP - 58
EP - 67
PB - RILEM Publications SARL
CY - Paris
AN - OPUS4-55737
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, Ricky
A1 - Sturm, Patrick
A1 - Geddes, D.A.
A1 - Keßler, S.
A1 - Walkley, B.
A1 - Gluth, Gregor
T1 - The influence of curing temperature on the strength and phase assemblage of hybrid cements based on GGBFS/FA blends
N2 - Hybrid cements are composites made of Portland cement or Portland clinker and one or more supplementary cementitious materials like slag, fly ash or metakaolin, activated with an alkali salt. To date, their hydration mechanism and the phase formation at various temperatures is insufficiently understood, partly due to the large variability of the raw materials used. In the present study, three hybrid cements based on ground granulated blast furnace slag, fly ash, Portland clinker and sodium sulfate, and an alkali-activated slag/fly ash blend were cured at 10 and 21.5°C, and subsequently analyzed by XRD, 27Al MAS NMR, and TGA. The compressive strength of the hybrid cements was higher by up to 27% after 91-day curing at 10°C, compared to curing at 21.5°C. The experimental results as well as thermodynamic modeling indicate that the differences in compressive strength were related to a different phase assemblage, mainly differing amounts of strätlingite and C-N-A-S-H, and the associated differences of the volume of hydration products. While the strätlingite was amorphous to X-rays, it could be identified by 27Al MAS NMR spectroscopy, TGA and thermodynamic modeling. The microstructural properties of the hybrid cements and the alkali-activated slag/fly ash blend as well as the compatibility between thermodynamic modeling results and experimental data as a function of curing temperature and time are discussed.
KW - Hybrid cements
KW - Strätlingite
KW - Thermodynamic modelling
KW - Hydration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557767
DO - https://doi.org/10.3389/fmats.2022.982568
SN - 2296-8016
VL - 9
SP - 1
EP - 16
PB - Frontiers
AN - OPUS4-55776
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de O. Primo, J.
A1 - Horsth, D.F.
A1 - de S. Correa, J.
A1 - Das, A.
A1 - Bittencourt, C.
A1 - Umek, P.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Yusenko, Kirill
A1 - Zanetta, C.
A1 - Anaissi, F.J.
T1 - Synthesis and Characterization of Ag/ZnO Nanoparticles for Bacteria Disinfection in Water
N2 - n this study, two green synthesis routes were used for the synthesis of Ag/ZnO nanoparticles, using cassava starch as a simple and low-cost effective fuel and Aloe vera as a reducing and stabilizing agent. The Ag/ZnO nanoparticles were characterized and used for bacterial dis-
infection of lake water contaminated with Escherichia coli (E. coli). Characterization indicated the formation of a face-centered cubic structure of metallic silver nanoparticles with no insertion of Ag into the ZnO hexagonal wurtzite structure. Physicochemical and bacteriological analyses described in “Standard Methods for the Examination of Water and Wastewater” were used to evaluate the efficiency of the treatment. In comparison to pure ZnO, the synthesized Ag/ZnO nanoparticles showed high efficiencies against Escherichia coli (E. coli) and general coliforms present in the lake
water. These pathogens were absent after treatment using Ag/ZnO nanoparticles. The results indicate that Ag/ZnO nanoparticles synthesized via green chemistry are a promising candidate for the treatment of wastewaters contaminated by bacteria, due to their facile preparation, low-cost synthesis,and disinfection efficiency.
KW - Synchrotron
KW - BAMline
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562440
DO - https://doi.org/10.3390/nano12101764
SN - 2079-4991
VL - 12
IS - 10
SP - 1
EP - 18
PB - MDPI
CY - Basel
AN - OPUS4-56244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Ke, X.
A1 - Vollpracht, A.
A1 - Weiler, L.
A1 - Bernal, S. A.
A1 - Cyr, M.
A1 - Dombrowski-Daube, K.
A1 - Geddes, D. A.
A1 - Grengg, C.
A1 - Le Galliard, C.
A1 - Nedeljkovic, M.
A1 - Provis, J. L.
A1 - Valentini, L.
A1 - Walkley, B.
T1 - Carbonation rate of alkali-activated concretes and high-volume SCM concretes: a literature data analysis by RILEM TC 281-CCC
N2 - The current understanding of the carbonation and the prediction of the carbonation rate of alkali-activated concretes is complicated inter alia by the wide range of binder chemistries used and testing conditions adopted. To overcome some of the limitations of individual studies and to identify general correlations between mix design parameters and carbonation resistance, the RILEM TC 281-CCC ‘Carbonation of Concrete with Supplementary Cementitious Materials’ Working Group 6 compiled and analysed carbonation data for alkali-activated concretes and mortars from the literature. For comparison purposes, data for blended Portland cement-based concretes with a high percentage of SCMs (≥ 66% of the binder) were also included in the database. The analysis indicates that water/CaO ratio and water/binder ratio exert an influence on the carbonation resistance of alkali-activated concretes; however, these parameters are not good indicators of the carbonation resistance when considered individually. A better indicator of the carbonation resistance of alkali-activated concretes under conditions approximating natural carbonation appears to be their water/(CaO + MgOeq + Na2Oeq + K2Oeq) ratio, where the subscript ‘eq’ indicates an equivalent amount based on molar masses. Nevertheless, this ratio can serve as approximate indicator at best, as other parameters also affect the carbonation resistance of alkali-activated concretes. In addition, the analysis of the database points to peculiarities of accelerated tests using elevated CO2 concentrations for low-Ca alkali-activated concretes, indicating that even at the relatively modest concentration of 1% CO2, accelerated testing may lead to inaccurate predictions of the carbonation resistance under natural exposure conditions.
KW - Alkali-activated materials
KW - Durability
KW - Carbonation
KW - Accelerated testing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560037
DO - https://doi.org/10.1617/s11527-022-02041-4
VL - 55
IS - 8
SP - 1
EP - 15
PB - Springer Nature
AN - OPUS4-56003
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dubey, A.
A1 - Hon Keat, C.
A1 - Shvartsman, V.
A1 - Yusenko, Kirill
A1 - Escobar, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Hagemann, U.
A1 - Kovalenko, S.
A1 - Stächler, J.
A1 - Lupascu, D.
T1 - Mono-, Di-, and Tri-valent Cation Doped BiFe0.95Mn0.05O3 Nanoparticles: Ferroelectric Photocatalysts
N2 - The ferroelectricity of multivalent co-doped Bismuth ferrite (BiFeO3; BFO) nanoparticles (NPs) is revealed and utilized for light photocatalysis exploiting their narrow electronic band gap. The photocatalytic activity of ferroelectric photocatalysts BiFe0.95Mn0.05O3 (BFM) NPs and mono-, di-, or tri-valent cations (Ag+, Ca2+, Dy3+; MDT) co-incorporated BFM NPs are studied under ultrasonication and in acidic conditions. We find that such doping enhances the photocatalytic activity of the ferroelectric NPs approximately three times. The correlation of the photocatalytic activity with structural, optical, and electrical properties of the doped NPs is established. The increase of spontaneous polarization by the mono- and tri-valent doping is one of the major factors in enhancing the photocatalytic performance along with other factors such as stronger light absorption in the visible range, low recombination rate of charge carriers and larger surface area of NPs. A-site doping of BFO NPs by divalent elements suppresses the polarization, whereas trivalent (Dy3+) and monovalent (Ag+) cations provide an increase of polarization. The depolarization field in these single domain NPs acts as a driving force to mitigate recombination of the photoinduced charge carriers.
KW - Piezoresponse
KW - Bismuth Ferrite
KW - Nanoparticles
KW - Photocatalysis
KW - Ferroelectric
KW - Polarization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557230
DO - https://doi.org/10.1002/adfm.202207105
SN - 1616-301X
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-55723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Sebastian
A1 - Bertmer, M.
A1 - Gluth, Gregor
T1 - Sol–gel synthesis and characterization of lithium aluminate (L–A–H) and lithium aluminosilicate (L–A–S–H) gels
N2 - Hydrous lithium aluminosilicate (L–A–S–H) and lithium aluminate (L–A–H) gels are candidate precursors for glass-ceramics and ceramics with potential advantages over conventional processing routes. However, their structure before calcination remained largely unknown, despite the importance of precursor structure on the properties of the resulting materials. In the present study, it is demonstrated that L–A–S–H and L–A–H gels with Li/Al ≤ 1 can be produced via an organic steric entrapment route, while higher Li/Al ratios lead to crystallization of gibbsite or nordstrandite. The composition and the structure of the gels was studied by thermogravimetric analysis, X-ray diffraction, 27Al and 29Si magic-angle spinning nuclear magnetic resonance, and Raman spectroscopy. Aluminium was found to be almost exclusively in six-fold coordination in both the L–A–H and the L–A–S–H gels. Silicon in the L–A–S–H gels was mainly in Q4 sites and to a lesser extent in Q3 sites (four-fold coordination with no Si–O–Al bonds). The results thus indicate that silica-rich and aluminium-rich domains formed in these gels.
KW - Lithium aluminosilicates
KW - Raman spectroscopy
KW - Sol-gel
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558756
DO - https://doi.org/10.1111/ijac.14187
SN - 1546-542X
VL - 19
IS - 6
SP - 3179
EP - 3190
PB - Wiley
AN - OPUS4-55875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Margreiter, R.
A1 - Baumann, J.
A1 - Mantouvalou, I.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Strub, E.
T1 - Investigations on fire-gilding
N2 - Fire-gilding is a historic technique for the application of golden layers on a number of different base materials utilizing a gold amalgam. This technique leaves a significant amount of Hg in the golden layer, giving archeometrists a reliable indicator to identify firegildings.
Recent findings on presumably fire-gilded objects have shown in several cases significantly lower Hg content than previously studied objects. This prompted a synchrotron-based X-ray fluorescence investigation into the Hg distribution along the material–gilding interface, as well as a series of measurements regarding the Hg content development in fire-gilded samples during artificial aging. This work presents findings on laboratory-prepared fire-gildings, indicating an Hg enrichment at the interface of firegilded silver samples. Notably, such an enrichment is missing in fire-gilded copper samples. Further, it is confirmed that fire-gilded layers typically do not undercut an Hg bulk content of 5%. In this light, it seems improbable that ancient samples that contain <5% Hg are fire-gilded. The results presented in this study might lead to a non-destructive method to identify the Hg enrichment at the interface. This might be obtained by a combination of different non-destructive measurements and might also work unambiguously in samples in which the gold top layer is altered.
KW - BAMline
KW - X-Ray Fluorescence
KW - Gilding
KW - Depth profile
KW - Archaeometry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552885
DO - https://doi.org/10.1111/arcm.12797
SN - 0003-813X
SP - 1
EP - 14
PB - Wiley online library
AN - OPUS4-55288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wagner, F.
A1 - Fellinger, Tim-Patrick
T1 - Evaluation of the Specific Activity of MNCs and the Intrinsic Activity of Tetrapyrrolic FeN4 Sites for the Oxygen Reduction Reaction
N2 - M−N−C electrocatalysts are considered pivotal to replace expensive precious group metal-based materials in electrocatalytic conversions. However, their development is hampered by the limited availability of methods for the evaluation of the intrinsic activity of different active sites, like pyrrolic FeN4 sites within Fe−N−Cs. Currently, new synthetic procedures based on active-site imprinting followed by an ion exchange reaction, e.g. Zn-to-Fe, are producing single-site M−N−Cs with outstanding activity. Based on the same replacement principle, we employed a conservative iron extraction to partially remove the Fe ions from the N4 cavities in Fe−N−Cs. Having catalysts with the same morphological properties and Fe ligation that differ solely in Fe content allows for the facile determination of the decrease in density of active sites and their turn-over frequency. In this way, insight into the specific activity of M−N−Cs is obtained and for single-site catalysts the intrinsic activity of the site is accessible. This new approach surpasses limitations of methods that rely on probe molecules and, together with those techniques, offers a novel tool to unfold the complexity of Fe−N−C catalyst and M−N−Cs in general.
KW - Fe-N-C catalysts
KW - M-N-C catalysts
KW - Fuel Cells
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567406
DO - https://doi.org/10.1002/anie.202207089
SN - 1433-7851
VL - 61
IS - 50
SP - 1
EP - 6
PB - Wiley-VHC
AN - OPUS4-56740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Iro, M.
A1 - Ingerle, D.
A1 - Radtke, Martin
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Kregsamer, P.
A1 - Streli, C.
T1 - Investigation of polycapillary half lenses for quantitative confocal micro-X-ray fluorescence analysis
N2 - The use of polycapillary optics in confocal micro-X-ray fluorescence analysis (CMXRF) enables the destruction-free 3D investigation of the elemental composition of samples. The energy-dependent transmission properties, concerning intensity and spatial beam propagation of three polycapillary half lenses, which are vital for the quantitative interpretation of such CMXRF measurements, are investigated in a monochromatic confocal laboratory setup at the Atominstitut of TU Wien, and a synchrotron setup on the BAMline beamline at the BESSY II Synchrotron, Helmholtz-Zentrum-Berlin. The empirically established results, concerning the intensity of the transmitted beam, are compared with theoretical values calculated with the polycap software package and a newly presented analytical model for the transmission function.
The resulting form of the newly modelled energy-dependent transmission function is shown to be in good agreement with Monte Carlo simulated results for the complete energy regime, as well as the empirically established results for the energy regime between 6 keV and 20 keV. An analysis of possible fabrication errors was conducted via pinhole scans showing only minor fabrication errors in two of the investigated polycapillary optics. The energy-dependent focal spot size of the primary polycapillary was investigated in the laboratory via the channel-wise evaluation of knife-edge scans. Experimental results are compared with data given by the manufacturer as well as geometric estimations for the minimal focal spot size. Again, the resulting measurement points show a trend in agreement with geometrically estimated results and manufacturer data.
KW - BAMline
KW - Synchrotron
KW - Capillary
KW - confocal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562430
DO - https://doi.org/10.1107/S1600577522009699
SN - 1600-5775
VL - 29
SP - 1376
EP - 1384
PB - International Union of Crystallography
CY - Chester
AN - OPUS4-56243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dobosy, Péter
A1 - Nguyen, Hoang Thi Phuong
A1 - Záray, Gyula
A1 - Streli, Christina
A1 - Ingerle, Dieter
A1 - Ziegler, Philipp
A1 - Radtke, Martin
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Endrédi, Anett
A1 - Fodor, Ferenc
T1 - Effect of iodine species on biofortification of iodine in cabbage plants cultivated in hydroponic cultures
N2 - Iodine is an essential trace element in the human diet because it is involved in the synthesis of thyroid hormones. Iodine deficiency affects over 2.2 billion people worldwide, making it a significant challenge to find plant-based sources of iodine that meet the recommended daily intake of this trace element. In this study, cabbage plants were cultivated in a hydroponic system containing iodine at concentrations ranging from 0.01 to 1.0 mg/L in the form of potassium iodide or potassium iodate. During the experiments, plant physiological parameters, biomass production, and concentration changes of iodine and selected microelements in different plant parts were investigated. In addition, the oxidation state of the accumulated iodine in root samples was determined. Results showed that iodine addition had no effect on photosynthetic efficiency and chlorophyll content. Iodide treatment did not considerably stimulate biomass production but iodate treatment increased it at concentrations less than 0.5 mg/L. Increasing iodine concentrations in the nutrient solutions increased iodine content in all plant parts; however, the iodide treatment was 2–7 times more efficient than the iodate treatment. It was concluded, that iodide addition was more favourable on the target element accumulation, however, it should be highlighted that application of this chemical form in nutrient solution decreased the concetrations of selected micoelement concentration comparing with the control plants. It was established that iodate was reduced to iodide during its uptake in cabbage roots, which means that independently from the oxidation number of iodine (+ 5, − 1) applied in the nutrient solutions, the reduced form of target element was transported to the aerial and edible tissues.
KW - BAMline
KW - XANES
KW - Synchrotron
KW - Lodine
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608330
DO - https://doi.org/10.1038/s41598-024-66575-z
VL - 14
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-60833
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cakir, Cafer Tufan
A1 - Bogoclu, Can
A1 - Emmerling, Franziska
A1 - Streli, Christina
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
T1 - Machine learning for efficient grazing-exit x-ray absorption near edge structure spectroscopy analysis: Bayesian optimization approach
N2 - In materials science, traditional techniques for analyzing layered structures are essential for obtaining information about local structure, electronic properties and chemical states. While valuable, these methods often require high vacuum environments and have limited depth profiling capabilities. The grazing exit x-ray absorption near-edge structure (GE-XANES) technique addresses these limitations by providing depth-resolved insight at ambient conditions, facilitating in situ material analysis without special sample preparation. However, GE-XANES is limited by long data acquisition times, which hinders its practicality for various applications. To overcome this, we have incorporated Bayesian optimization (BO) into the GE-XANES data acquisition process. This innovative approach potentially reduces measurement time by a factor of 50. We have used a standard GE-XANES experiment, which serve as reference, to validate the effectiveness and accuracy of the BO-informed experimental setup. Our results show that this optimized approach maintains data quality while significantly improving efficiency, making GE-XANES more accessible to a wider range of materials science applications.
KW - Machine Learning
KW - GE-XANES
KW - Bayesian Optimization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603955
DO - https://doi.org/10.1088/2632-2153/ad4253
VL - 5
IS - 2
SP - 1
EP - 12
PB - IOP Publishing
AN - OPUS4-60395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernal, S. A.
A1 - Dhandapani, Y.
A1 - Elakneswaran, Y.
A1 - Gluth, Gregor
A1 - Gruyaert, E.
A1 - Juenger, M. C. G.
A1 - Lothenbach, B.
A1 - Olonade, K. A.
A1 - Sakoparnig, M.
A1 - Shi, Z.
A1 - Thiel, C.
A1 - Van den Heede, P.
A1 - Vanoutrive, H.
A1 - von Greve-Dierfeld, S.
A1 - De Belie, N.
A1 - Provis, J. L.
T1 - Report of RILEM TC 281-CCC: A critical review of the standardised testing methods to determine carbonation resistance of concrete
N2 - The chemical reaction between CO2 and a blended Portland cement concrete, referred to as carbonation, can lead to reduced performance, particularly when concrete is exposed to elevated levels of CO2 (i.e., accelerated carbonation conditions). When slight changes in concrete mix designs or testing conditions are adopted, conflicting carbonation results are often reported. The RILEM TC 281-CCC ‘Carbonation of Concrete with Supplementary Cementitious Materials’ has conducted a critical analysis of the standardised testing methodologies that are currently applied to determine carbonation resistance of concrete in different regions. There are at least 17 different standards or recommendations being actively used for this purpose, with significant differences in sample curing, pre-conditioning, carbonation exposure conditions, and methods used for determination of carbonation depth after exposure. These differences strongly influence the carbonation depths recorded and the carbonation coefficient values calculated. Considering the importance of accurately determining carbonation potential of concrete, not just for predicting their durability performance, but also for determining the amount of CO2 that concrete can re-absorb during or after its service life, it is imperative to recognise the applicability and limitations of the results obtained from different tests. This will enable researchers and practitioners to adopt the most appropriate testing methodologies to evaluate carbonation resistance, depending on the purpose of the conclusions derived from such testing (e. g. materials selection, service life prediction, CO2 capture potential).
KW - Concrete
KW - Cement
KW - Carbonation
KW - Testing
KW - Standards
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609364
DO - https://doi.org/10.1617/s11527-024-02424-9
VL - 57
SP - 1
EP - 31
PB - Springer Nature
AN - OPUS4-60936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huang, Junhao
A1 - Klahn, Marcus
A1 - Tian, Xinxin
A1 - Bartling, Stephan
A1 - Zimina, Anna
A1 - Radtke, Martin
A1 - Rockstroh, Nils
A1 - Naliwajko, Pawel
A1 - Steinfeldt, Norbert
A1 - Peppel, Tim
A1 - Grunwaldt, Jan‐Dierk
A1 - Logsdail, Andrew J.
A1 - Jiao, Haijun
A1 - Strunk, Jennifer
T1 - Fundamental Structural and Electronic Understanding of Palladium Catalysts on Nitride and Oxide Supports
N2 - The nature of the support can fundamentally affect the function of a heterogeneous catalyst. For the novel type of isolated metal atom catalysts, sometimes referred to as single‐atom catalysts, systematic correlations are still rare. Here, we report a general finding that Pd on nitride supports (non‐metal and metal nitride) features a higher oxidation state compared to that on oxide supports (non‐metal and metal oxide). Through thorough oxidation state investigations by X‐ray absorption spectroscopy (XAS), X‐ray photoelectron spectroscopy (XPS), CO‐DRIFTS, and density functional theory (DFT) coupled with Bader charge analysis, it is found that Pd atoms prefer to interact with surface hydroxyl group to form a Pd(OH)x species on oxide supports, while on nitride supports, Pd atoms incorporate into the surface structure in the form of Pd−N bonds. Moreover, a correlation was built between the formal oxidation state and computational Bader charge, based on the periodic trend in electronegativity.
KW - BAmline
KW - XANES
KW - Catalyst
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608341
DO - https://doi.org/10.1002/anie.202400174
SN - 1433-7851
VL - 63
IS - 20
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-60834
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Senges, Gene
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Lindič, Tilen
A1 - Gully, Tyler A.
A1 - Winter, Marlon
A1 - Radtke, Martin
A1 - Röder, Bettina
A1 - Steinhauer, Simon
A1 - Paulus, Beate
A1 - Emmerling, Franziska
A1 - Riedel, Sebastian
T1 - Unravelling highly oxidized nickel centers in the anodic black film formed during the Simons process by in situ X-ray absorption near edge structure spectroscopy
N2 - The electrofluorination after Simons has been used for the last century to produce everyday life materials. An in situ XANES investigation of the controversially debated black film apparent in the Simons process revealed high-valent nickel centers.
KW - Synchrotron
KW - BAMline
KW - XANES
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608366
DO - https://doi.org/10.1039/d3sc06081k
SN - 2041-6520
VL - 15
IS - 12
SP - 4504
EP - 4509
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, Ricky
A1 - Sturm, Patrick
A1 - Keßler, S.
A1 - Gluth, Gregor
ED - Lothenbach, B.
ED - Wieland, E.
ED - Altmaier, M.
T1 - Influence of salt aggregate on the degradation of hybrid alkaline cement (HAC) concretes in magnesium chloride-rich saline solution simulating evaporite rock
N2 - Concretes produced from salt aggregate and hybrid alkaline cements, an alkali-activated slag/fly ash blend, or a Portland cement were exposed to a magnesium chloride-rich saline solution ([Mg2+] = 3.6 m, [Cl−] = 8.3 m), representing a solution formed after contact of surface water with evaporite rock (rock salt) in a nuclear waste repository. The hydration and deterioration of the concretes were studied with X-ray diffraction, thermogravimetric analysis, pH mapping and permeability measurements. The results show that calcium silicate hydrate (C-S-H) or sodium-substituted calcium aluminium silicate hydrate (C-N-A-S-H) and Friedel's salt were the major reaction products in the concretes prior to exposure to the saline solution. During exposure to the saline solution, increasing amounts of C-S-H/C-N-A-S-H dissolved, and gypsum and a secondary AFm phase formed. The durability of the concretes improved with increasing amounts of Portland clinker in the cements, due to the associated differences in permeability and chemical resistance. Nevertheless, a massive increase of permeability occurred for all concretes, likely caused by crack formation due to the formation of gypsum from anhydrite in the salt aggregate. Thus, the behavior of the concretes differed from, and was more complex than, the behavior of plain cement pastes.
T2 - Joint 6th International Workshop on Mechanisms and Modelling of Waste/Cement Interactions (JCCW 2023)
CY - Prague, Czech Republic
DA - 20.11.2023
KW - Nuclear waste repository
KW - Evaporite rock
KW - Magnesium chloride brine
KW - Concrete
KW - Hybrid alkaline cement
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599928
DO - https://doi.org/10.1016/j.apgeochem.2024.106027
SN - 0883-2927
SN - 1872-9134
VL - 168
SP - 1
EP - 14
PB - Elsevier
AN - OPUS4-59992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Glazyrin, Konstantin
A1 - Spektor, Kristina
A1 - Bykov, Maxim
A1 - Dong, Weiwei
A1 - Yu, Ji‐Hun Yu
A1 - Yang, Sangsun Yang
A1 - Lee, Jai‐Sung Lee
A1 - Divinski, Sergiy V.
A1 - Hanfland, Michael
A1 - Yusenko, Kirill
T1 - High‐Entropy Alloys and Their Affinity with Hydrogen: From Cantor to Platinum Group Elements Alloys
N2 - AbstractProperties of high‐entropy alloys are currently in the spotlight due to their promising applications. One of the least investigated aspects is the affinity of these alloys to hydrogen, its diffusion, and reactions. In this study, high pressure is applied at ambient temperature and stress‐induced diffusion of hydrogen is investigated into the structure of high‐entropy alloys (HEA) including the famous Cantor alloy as well as less known, but nevertheless important platinum group (PGM) alloys. By applying X‐ray diffraction to samples loaded into diamond anvil cells, a comparative investigation of transition element incorporating HEA alloys in Ne and H2 pressure‐transmitting media is performed at ambient temperature. Even under stresses far exceeding conventional industrial processes, both Cantor and PGM alloys show exceptional resistance to hydride formation, on par with widely used industrial grade Cu–Be alloys. The observations inspire optimism for practical HEA applications in hydrogen‐relevant industry and technology (e.g., coatings, etc), particularly those related to transport and storage.
KW - XRD
KW - HIgh entropy,
KW - Cantor
KW - Alloys
KW - Synchrotron
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604170
DO - https://doi.org/10.1002/advs.202401741
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-60417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - Low, Jian Liang
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Paulus, B.
A1 - Fellinger, Tim-Patrick
T1 - The Tetrapyrollic Motif in Nitrogen Doped Carbons and M-N-C Electrocatalysts as Active Site in the Outer-Sphere Mechanism of the Alkaline Oxygen Reduction Reaction
N2 - Development and fundamental understanding of precious-group-metal-free electrocatalysts is hampered by limitations in the quantification of the intrinsic activity of different catalytic sites and understanding the different reaction mechanisms. Comparing isomorphic nitrogen-doped carbons, Zn-N-Cs and Fe-N-Cs with the common tetrapyrrolic motif, a catalyst-independent outer-sphere rate-determining step in the alkaline oxygen reduction reaction is observed. Density functional theory (DFT) simulations on tetrapyrrolic model structures indicate the highest occupied molecular orbital (HOMO) level as a good descriptor for the catalytic activity. Contour plots suggest that the electron transfer occurs directly from the tetrapyrrolic coordination site, rather than from the metal center. Metal-free tetrapyrrolic N4 sites are discovered to be highly active oxygen reduction reaction (ORR) active sites in alkaline that reach turnover frequencies (TOF) of 0.33 and 1.84 s−1 at 0.80 and 0.75 VRHE in the order of magnitude of tetrapyrrolic Fe–N4 sites in the acidic ORR. While Zn-coordination lowers the HOMO level and therefore the catalytic activity, Fe-coordination lifts the HOMO level resulting in TOF values of 0.4 and 4 s−1 for tetrapyrrolic Fe–N4 sites at 0.90 and 0.85 VRHE, respectively. At higher mass activities, the peroxide reduction becomes rate-limiting, where highest peroxide production rates are observed for the nitrogen-doped carbon.
KW - Tetrapyrollic
KW - Motif
KW - Nitrogen
KW - Carbons
KW - Alkaline Oxygen
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606239
DO - https://doi.org/https://doi.org/10.1002/aenm.202400482
SN - 1614-6832
VL - 2024
SP - 1
EP - 8
PB - Wiley-VCH
AN - OPUS4-60623
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hajhariri, Aliasghar
A1 - Eberwein, Robert
A1 - Camplese, Davide
A1 - Scarponi, Giordano Emrys
A1 - Cozzani, Valerio
A1 - Otremba, Frank
A1 - Seidlitz, Holger
T1 - Non-combustible MLI based insulation behavior under fire condition - Experimental and numerical investigation
N2 - The number of applications that demand zero-emission energy carriers, such as liquified hydrogen (LH2), is increasing worldwide. LH2 is typically transported or stored under cryogenic conditions. Storage in such conditions requires super thermal insulations which maintain very low boil-off for a prolonged time. Multi-Layer insulation (MLI) finds widespread use in cryogenic applications, designed to effectively restrict heat inleak towards cryogenic fluids. However, recent studies evidenced that exposure to high heat fluxes, such as in the event of a fire accident, can cause the thermal degradation of the insulation material, resulting in the severe collapse of its heat resistance performance. Therefore, the risk of rapid tank pressurization and its connection to the risk of BLEVE may be possible. This study proposes a numerical model to assess the performances of aluminum-based MLI materials under fire conditions. The model offers insights into the total heat transfer rate through the insulation, serving as a
KW - Multi-Layer Insulation
KW - Cryogenic
KW - Liquid Hydrogen
KW - CFD
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617780
DO - https://doi.org/10.1016/j.psep.2024.11.037
VL - 193
SP - 603
EP - 620
PB - Elsevier B.V.
AN - OPUS4-61778
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Camplese, Davide
A1 - Scarponi, Giordano Emrys
A1 - Eberwein, Robert
A1 - Hajhariri, Aliasghar
A1 - Otremba, Frank
A1 - Cozzani, Valerio
T1 - Comparative performance assessment of multilayer insulation (MLI) systems for liquid hydrogen vessels in fire scenarios
N2 - Multilayer Insulation (MLI) systems are a mature technology for cryogenic liquid hydrogen (LH2) tank thermal insulation. Recent tests evidenced that MLI materials may be damaged when exposed to fire, resulting in critical safety issues in the case of accidents. Thus, an innovative approach to the performance assessment of aluminum and polyester-based MLIs for LH2 tanks in fire scenarios was developed. A specific model integrating the hightemperature degradation of MLIs and the thermodynamic modeling of the tank lading was coupled to specific key performance indicators. Results of the analysis applied to a vehicle-scale tank equipped with 80 MLI layers indicate that MLI degradation and consequent tank failure may occur in less than 20 min for external shell temperatures above 1160 K in the presence of full engulfment, regardless of insulation used. Conversely, degradation does not occur earlier than 3600s below 603 and 928 K for polyester and aluminum-based MLI, respectively.
KW - LH2
KW - LNG
KW - Cryogenic storage tank
KW - Fire
KW - Insulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630841
DO - https://doi.org/10.1016/j.ijhydene.2025.04.534
SN - 0360-3199
VL - 135
SP - 537
EP - 552
PB - Elsevier Ltd.
AN - OPUS4-63084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Denora, Isabella
A1 - Clute, Clara
A1 - Murillo, Natalia Cano
A1 - Theiler, Geraldine
A1 - Balasooriya, Winoj
A1 - Kaiser, Andreas
A1 - Fasching, Michael
A1 - Schwarz, Thomas
A1 - Marano, Claudia
T1 - A study on the mechanical behaviour of carbon black and Struktosil-filled NBR compounds for hydrogen applications
N2 - This study investigates the effect of the addition of a 2D filler (Struktosil) to a carbon black-filled acrylonitrile butadiene rubber, developed for seals in hydrogen applications. Several characterization methods have been adopted. The addition of Struktosil increases the stiffness of the material up to a strain of about 100%, to a lesser extent in presence of a plasticizer. The dissipative response of the material is increased by Struktosil addition and decreased in presence of the plasticizer. Concerning fracture behaviour, the crack initiation and Rapid Gas Decompression (RGD) resistance were not affected by the addition of Struktosil but decreased in presence of plasticizer. Furthermore, the addition of Struktosil had a positive effect on crack propagation resistance. The effects of pressurized hydrogen exposure on physical-mechanical properties were also evaluated and correlated with the results. A correlation between fracture toughness and RGD resistance has been also attempted.
KW - Acrylonitrile Butadiene rubber
KW - Fracture mechanics
KW - 2D filler
KW - High-pressure hydrogen
KW - Rapid gas decompression
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648285
DO - https://doi.org/10.1016/j.ijhydene.2025.03.122
SN - 0360-3199
VL - 118
SP - 407
EP - 416
PB - Elsevier Ltd.
AN - OPUS4-64828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sarif, Raduan
A1 - Tiebe, Carlo
A1 - Herglotz, Christian
T1 - Early Response Prediction for H2 Sensors
N2 - Green hydrogen (H2) is essential for the global transition to clean energy; it will significantly reduce emissions from heavy industry and the long-distance transport system. H2 can be used as fuel in fuel cells, storing surplus renewable energy, and as a feedstock in industrial processes. However, H2 faces significant safety challenges during storage and transportation. Accidents due to H2 leakage and explosions raise serious concerns due to its high flammability, rapid diffusion in air, and extremely low ignition energy. To mitigate risks associated with H2 leakages, reliable and automated H2 safety systems are essential for emergency repairs or shutdown. An early response from H2 sensors is crucial for early warning in accidents. The earlier response time of H2 sensors is often constrained by their sensor principle, which is heavily influenced by the sensor material’s properties. This study explores methods for earlier sensor response through predictive algorithms. Specifically, we investigate transient response predictions using a First-Order (FO) model and propose improvements through the First-Order with early response and the First-Order with adapted early response model. Both models can predict the stable value of the H2 sensor response from a small time window, which is 70.89% and 83.72% earlier, respectively, than the time required for the sensor hardware to reach it physically. The model’s performance is evaluated by calculating the fitting error with a 2 % threshold. Our current research lays the groundwork for future advancements in real-time sensor response predictions for hydrogen leakage.
T2 - IARIA Congress 2025 : The 2025 IARIA Annual Congress on Frontiers in Science, Technology, Services, and Applications
CY - Venice, Italy
DA - 06.07.2025
KW - H2 Safety
KW - H2 leakage detection
KW - First-Order (FO) model
KW - H2 Sensor data analysis
KW - H2 sensor response predictions
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640676
UR - https://www.thinkmind.org/articles/iaria_congress_2025_1_250_50159.pdf
SN - 978-1-68558-284-5
SP - 1
EP - 8
PB - IARIA Press
CY - Wilmington
AN - OPUS4-64067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sarif, Raduan
A1 - Tiebe, Carlo
A1 - Herglotz, Christian
T1 - Analysis of Methods for Predicting H2 Sensor Responses
N2 - Hydrogen (H2) is crucial for replacing fossil fuels and achieving net-zero emissions, but its flammability and explosiveness pose safety challenges. Rapid H2 leak detection is essential for triggering emergency accidents. However, H2 sensor response is constrained by material properties and gas flow dynamics, causing response and detection delays. Our current study explores various available algorithms for H2 sensor response prediction from early responses with a small time window, accelerating leakage detection. Our findings identify the most efficient algorithms for real-time implementation, enhancing H2 safety systems.
T2 - SMSI 2025 2025-05-06 - 2025-05-08 Nürnberg
CY - Nuremberg, Germany
DA - 06.05.2025
KW - H2 safety
KW - Early H2 leakage detection
KW - Prediction algorithms
KW - Stable H2 value prediction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640617
SN - 978-3-910600-06-5
DO - https://doi.org/10.5162/SMSI2025/C6.3
SP - 169
EP - 170
PB - AMA Verband für Sensorik und Messtechnik e.V.
CY - Berlin
AN - OPUS4-64061
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz
A1 - Karafiludis, Stephanos
A1 - Pimentel, Carlos
A1 - Montes-Hernández, German
A1 - Kochovski, Zdravko
A1 - Bienert, Ralf
A1 - Weimann, Karin
A1 - Emmerling, Franziska
A1 - Scoppola, Ernesto
A1 - Van Driessche, Alexander E.S.
T1 - Solution-driven processing of calcium sulfate: The mechanism of the reversible transformation of gypsum to bassanite in brines
N2 - Here, we show that calcium sulfate dihydrate (gypsum) can be directly, rapidly and reversibly converted to calcium sulfate hemihydrate (bassanite) in high salinity solutions (brines). The optimum conditions for the efficient production of bassanite in a short time (<5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the better-known behaviour of the bassanite phase in low-salt environments. In low-salinity aqueous solutions, bassanite is considered to be metastable with respect to gypsum and anhydrite, and therefore gypsum-to-bassanite conversion does not occur in pure water. Interestingly, the high-salinity transformation of gypsum-to-bassanite has been reported by many authors and used in practice for several decades, although its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures was inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline phase for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios.
KW - Industrial and Manufacturing Engineering
KW - Strategy and Management
KW - General Environmental Science
KW - Renewable Energy, Sustainability and the Environment
KW - Building and Construction
KW - Calcium sulfate
KW - Gypsum
KW - Bassanite
KW - Scattering
KW - Raman
KW - In situ
KW - Synchrotron
KW - BESSY
KW - MySpot
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594698
UR - https://www.sciencedirect.com/science/article/pii/S0959652624004591#appsec1
DO - https://doi.org/10.1016/j.jclepro.2024.141012
SN - 0959-6526
VL - 440
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-59469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grengg, C.
A1 - Gluth, Gregor
A1 - Mittermayr, F.
A1 - Ukrainczyk, N.
A1 - Bertmer, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Leis, A.
A1 - Dietzel, M.
T1 - Deterioration mechanism of alkali-activated materials in sulfuric acid and the influence of Cu: A micro-to-nano structural, elemental and stable isotopic multi-proxy study
N2 - In this study, a multi-proxy approach combining 29Si, 27Al and 1H MAS-NMR, FEG-EPMA, XANES at the Cu K-edge and XRD analytics with hydrochemical tools such as ICP-OES analyses, oxygen-isotope signatures, and thermodynamic modelling was applied to K-silicate-activated metakaolin specimens - with and without CuSO4·5H2O addition - exposed to sulfuric acid at pH = 2 for 35 days. The results revealed a multistage deterioration mechanism governed by (i) acid diffusion, (ii) leaching of K-A-S-H, (iii) microstructural damage related to precipitation of expansive (K,Ca,Al)-sulfate-hydrate phases (iv) complete dissolution of the K-A-S-H framework, (v) and formation of silica gel in the outermost corroded regions. Copper ions were mainly located in layered spertiniite-chrysocolla-like phases in the as-cured materials. The results demonstrate an overall negative effect of Cu addition on chemical material durability, implying that the reported higher durability of Cu-doped AAM in biocorrosion environments can be best explained by bacteriostatic effects.
KW - Alkali-activated materials
KW - Acid resistance
KW - Microbially induced corrosion
KW - MIC
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520567
DO - https://doi.org/10.1016/j.cemconres.2021.106373
SN - 0008-8846
VL - 142
SP - 1
EP - 15
PB - Elsevier
CY - Oxford
AN - OPUS4-52056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radtke, Martin
A1 - Buzanich, Günter
A1 - Curado, Jessica
A1 - Reinholz, Uwe
A1 - Riesemeier, Heinrich
A1 - Scharf, O.
T1 - Slicing - a new method for non destructive 3D elemental sensitive characterization of materials
N2 - Recent advances in synchrotron sources and detector technology have led to substantial improvements in spatial resolution and detection limits for X-ray fluorescence analysis (XRF). However, the non-destructive three-dimensional elemental sensitive characterization of samples remains a challenge. We demonstrate the use of the so-called 'Color X-ray Camera' (CXC) for 3D measurements for the first time. The excitation of the sample is realized with a thin sheet-beam. The stepwise movement of the sample allows getting the elemental distribution for each layer with one measurement. These layers can be combined to a full 3D dataset for each element afterwards. Since the information is collected layer by layer, there is no need to apply reconstruction techniques, which quite often are the reason for artifacts in the results achieved by computed tomography (CT). The field of applications is wide, as the 3D elemental distribution of a material contains clues to processes inside the samples from a variety of origins. The technique is of special interest and well suited for biological specimens, because their light matrix minimizes restricting absorption effects. Measurement examples of a hornet and the teeth of a Sorex araneus are shown.
KW - SR-microXRF
KW - 3D
KW - CXC
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324330
DO - https://doi.org/10.1039/c4ja00085d
SN - 0267-9477
SN - 1364-5544
VL - 29
IS - 8
SP - 1339
EP - 1344
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-32433
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Chen, K.
A1 - Radu, F.
A1 - Weschke, E.
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Yusenko, Kirill
T1 - Al-driven peculiarities of local coordination and magnetic properties in single-phase Alx-CrFeCoNi high-entropy alloys
N2 - Modern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision. The revealed unimodal and bimodal distributions of all five elements are in agreement with structure-dependent magnetic properties of studied alloys probed by magnetometry. A degree of surface atoms oxidation uncovered by soft X-rays suggests different kinetics of oxide formation for each type of constituents and has to be taken into account. X-ray magnetic circular dichroism technique employed at L2,3 absorption edges of transition metals demonstrates reduced magnetic moments of 3d metal constituents in the sub-Surface region of in situ cleaned fcc-structured Al0.3-CrFeCoNi compared to their bulk values. Extended to nanostructured versions of multicomponent alloys, such studies would bring new insights related to effects of high entropy mixing on low dimensions.
KW - X-ray magnetic circular dichroism (XMCD)
KW - High-entropy alloys
KW - Reverse Monte Carlo
KW - Magnetism
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530668
DO - https://doi.org/10.1007/s12274-021-3704-5
SN - 1998-0124
VL - 15
IS - 6
SP - 4845
EP - 4858
PB - Springer
AN - OPUS4-53066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lutz, C.
A1 - Breuckmann, M.
A1 - Hampel, S.
A1 - Kreyenschmidt, M.
A1 - Ke, X.
A1 - Beuermann, S.
A1 - Schafner, K.
A1 - Turek, T.
A1 - Kunz, U.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Fittschen, U. E. A.
T1 - Characterization of Dimeric Vanadium Uptake and Species in Nafion™ and Novel Membranes from Vanadium Redox Flow Batteries Electrolytes
N2 - A core component of energy storage systems like vanadium redox flow batteries (VRFB) is the polymer electrolyte membrane (PEM). In this work, the frequently used perfluorosulfonic-acid (PFSA) membrane Nafion™ 117 and a novel poly (vinylidene difluoride) (PVDF)-based Membrane are investigated. A well-known problem in VRFBs is the vanadium permeation through the membrane. The consequence of this so-called vanadium crossover is a severe loss of capacity. For a
better understanding of vanadium transport in membranes, the uptake of vanadium ions from electrolytes containing Vdimer(IV–V) and for comparison also V(II), V(III), V(IV), and V(V) by both membranes was studied. UV/VIS spectroscopy, X-ray absorption near edge structure spectroscopy (XANES), total reflection X-ray fluorescence spectroscopy (TXRF), inductively coupled plasma optical emission spectrometry (ICP-OES), and micro X-ray fluorescence spectroscopy (microXRF) were used to determine the vanadium concentrations and the species inside the membrane. The results strongly support that Vdimer(IV–V), a dimer formed from V(IV) and V(V), enters the nanoscopic water-body of Nafion™ 117 as such. This is interesting, because as of now, only the individual ions V(IV) and V(V) were considered to be transported through the membrane. Additionally, it was found that the Vdimer(IV–V) dimer partly dissociates to the individual ions in the novel PVDF-based membrane.
The Vdimer(IV–V) dimer concentration in Nafion™ was determined and compared to those of the other species. After three days of equilibration time, the concentration of the dimer is the lowest compared to the monomeric vanadium species. The concentration of vanadium in terms of the relative uptake λ = n(V)/n(SO3
) are as follows: V(II) [λ = 0.155] > V(III) [λ = 0.137] > V(IV) [λ = 0.124] > V(V) [λ = 0.053] > Vdimer(IV–V) [λ = 0.039]. The results show that the Vdimer(IV–V) dimer Needs to be considered in addition to the other monomeric species to properly describe the transport of vanadium through Nafion™ in VRFBs.
KW - MicroXRF
KW - VRFB
KW - PVDF-based membrane
KW - UV/VIS
KW - XANES
KW - TXRF
KW - ICP-OES
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530676
DO - https://doi.org/10.3390/membranes11080576
VL - 11
IS - 8
SP - 576
PB - MDPI
AN - OPUS4-53067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazlagić, Anera
A1 - Vogl, Jochen
A1 - Gluth, Gregor
A1 - Stephan, D.
T1 - Provenancing of cement using elemental analyses and isotope techniques – The state-of-the-art and future perspectives
N2 - With the aim of identifying the origin and the manufacturer of a cement, a reliable procedure that provides unambiguous results is needed. Such procedure could resolve practical issues in damage research, liability issues and forensic investigations. A substantial number of attempts for fingerprinting of building materials, including cement, has already been carried out during the last decades. Most of them were based on concentration analysis of the main elements/components. This review provides an overview of provenance studies of cement and the main approaches commonly used. Provenance studies of cement via isotope techniques are also presented and discussed as representatives of the state-of-the-art in the field. Due to the characteristic properties and the occurrence of carefully selected isotope ratios, unique fingerprints of different kinds of materials can be provided by these methods. This property has largely been explored in various scientific fields such as geo- and cosmochemistry, food forensics, archaeology, geochronology, biomedical studies, and climate change processes. However, the potential of isotope techniques in cement and concrete research for provenance studies has barely been investigated.
Therefore, the review outlines a suitable approach using isotope ratios, which could lead to reliable provenancing of cementitious materials in the future.
KW - Cement
KW - Sr isotopes
KW - Provenance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533762
DO - https://doi.org/10.1039/d1ja00144b
VL - 36
IS - 10
SP - 2030
EP - 2042
PB - The Royal Society of Chemistry
CY - Cambridge, UK
AN - OPUS4-53376
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Recent developments of X-ray absorption spectroscopy as analytical tool for biological and biomedical applications
N2 - X-ray absorption spectroscopy (XAS), in its various modalities, has gained exponential attention and applicability in the field of biological and biomedical systems. Particularly in this field, challenges like low concentration of analyte or proneness to radiation damage have certainly settle the basis for further analytical developments, when using X-ray based methods. Low concentration calls for higher sensitivity—by increasing the detection limits (DL); while susceptibility for radiation damage requires shorter measurement times and/or cryogenic sample environment possibilities. This manuscript reviews the latest analytical possibilities that make XAS more and more adequate to investigate biological or biomedical systems in the last 5 years.
KW - Biological & biomedical applications
KW - TXRF-XAS
KW - HERFD-XAS
KW - RXES
KW - Quick-XAS
KW - Dispersive-XAS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531206
DO - https://doi.org/10.1002/xrs.3254
SN - 0049-8246
VL - 51
IS - 3
SP - 1
EP - 10
PB - John Wiley & Sons Ltd
AN - OPUS4-53120
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazlagić, Anera
A1 - Russo, Francesco
A1 - Vogl, Jochen
A1 - Sturm, Patrick
A1 - Stephan, D.
A1 - Gluth, Gregor
ED - Resch-Genger, Ute
ED - Koch, Matthias
ED - Meermann, Björn
ED - Weller, Michael G.
T1 - Development of a sample preparation procedure for Sr isotope analysis of Portland cements
N2 - The 87Sr/86Sr isotope ratio can, in principle, be used for provenancing of cement. However, while commercial cements consist of multiple components, no detailed investigation into their individual 87Sr/86Sr isotope ratios or their influence on the integral 87Sr/86Sr isotope ratio of the resulting cement was conducted previously. Therefore, the present study aimed at determining and comparing the conventional 87Sr/86Sr isotope ratios of a diverse set of Portland cements and their corresponding Portland clinkers, the major component of these cements. Two approaches to remove the additives from the cements, i.e. to measure the conventional 87Sr/86Sr isotopic fingerprint of the clinker only, were tested, namely, treatment with a potassium hydroxide/sucrose solution and sieving on a 11-µm sieve. Dissolution in concentrated hydrochloric acid/nitric acid and in diluted nitric acid was employed to determine the 87Sr/86Sr isotope ratios of the cements and the individual clinkers. The aim was to find the most appropriate sample preparation procedure for cement provenancing, and the selection was realised by comparing the 87Sr/86Sr isotope ratios of differently treated cements with those of the corresponding clinkers. None of the methods to separate the clinkers from the cements proved to be satisfactory. However, it was found that the 87Sr/86Sr isotope ratios of clinker and cement generally corresponded, meaning that the latter can be used as a proxy for the clinker 87Sr/86Sr isotope ratio. Finally, the concentrated hydrochloric acid/nitric acid dissolution method was found to be the most suitable sample preparation method for the cements; it is thus recommended for 87Sr/86Sr isotope analyses for cement provenancing.
KW - Cement
KW - Provenancing
KW - Sr isotopes
KW - Portland clinker
KW - Dissolution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542239
DO - https://doi.org/10.1007/s00216-021-03821-7
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - 15 (Topical collection: Analytical methods and applications in the materials and life sciences)
SP - 4379
EP - 4389
PB - Springer
CY - Berlin
AN - OPUS4-54223
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Guerra, M.F.
A1 - Martinón-Torres, M.
A1 - Lemasson, Q.
A1 - Moignard, B.
A1 - Pacheco, C.
A1 - Pichon, L.
A1 - Macdonald, L.
A1 - Hess, M.
A1 - Tissot, I.
ED - Guerra, M. F.
ED - Martinón-Torres, M.
ED - Quirke, S.
T1 - Analytical approaches to Egyptian goldwork
N2 - The structure and composition of ancient gold objects retain information about their long history of manufacture, from the exploitation of the ore to the finishing touches, as well as evidence of their use, deposition, and degradation. By developing an efficient analytical strategy, it is possible to retrieve that information. This chapter sets the necessary foundation 131to explore fully the analytical results presented in the following chapters of this volume. The techniques employed in the analyses of the Egyptian jewellery are described and the analytical parameters provided. For more established techniques, only brief introductions are presented, while more recent developments are presented in greater detail.
KW - Gold
KW - Synchrotron
KW - D2XRF
KW - Egypt
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586039
DO - https://doi.org/10.17863/CAM.99681
SP - 131
EP - 191
AN - OPUS4-58603
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, Stefan
A1 - Bartling, Stephan
A1 - Parlinska-Wojtan, Magdalena
A1 - Wotzka, Alexander
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wohlrab, Sebastian
A1 - Abdel-Mageed, Ali M.
T1 - Stabilization of intermediate Mo oxidation states by Nb doping enhancing methane aromatization on Mo/HZSM-5 catalysts
N2 - The dehydroaromatization of methane is a promising process to produce aromatics and ultra-pure hydrogen. Increased yields and stability of Mo/HZSM-5 against irreversible deactivation were achieved via a redox interaction by doping with otherwise inert Nb.
KW - General Materials Science
KW - Sustainability and the Environment
KW - General Chemistry
KW - Renewable Energy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597670
DO - https://doi.org/10.1039/D3TA07532J
SN - 2050-7488
SP - 1
EP - 16
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59767
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, Alevtina
A1 - Gaertner, Daniel
A1 - Kuzmin, Alexei
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Schuck, Goetz
A1 - Zizak, Ivo
A1 - Wilde, Gerhard
A1 - Yusenko, Kirill
A1 - Divinski, Sergiy
T1 - Anomalies in the short-range local environment and atomic diffusion in single crystalline equiatomic CrMnFeCoNi high-entropy alloy
N2 - AbstractMulti-edge extended X-ray absorption fine structure (EXAFS) spectroscopy combined with reverse Monte Carlo (RMC) simulations was used to probe the details of element-specific local coordinations and component-dependent structure relaxations in single crystalline equiatomic CrMnFeCoNi high-entropy alloy as a function of the annealing temperature. Two representative states, namely a high-temperature state, created by annealing at 1373 K, and a low-temperature state, produced by long-term annealing at 993 K, were compared in detail. Specific features identified in atomic configurations of particular principal components indicate variations in the local environment distortions connected to different degrees of compositional disorder at the chosen representative temperatures. The detected changes provide new atomistic insights and correlate with the existence of kinks previously observed in the Arrhenius dependencies of component diffusion rates in the CrMnFeCoNi high-entropy alloy.
KW - Electrical and Electronic Engineering
KW - General Materials Science
KW - Condensed Matter Physics
KW - Atomic and Molecular Physics, and Optics
KW - CCMat
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597687
DO - https://doi.org/10.1007/s12274-024-6443-6
SN - 1998-0124
VL - 17
IS - 6
SP - 5336
EP - 5348
PB - Springer Science and Business Media LLC
AN - OPUS4-59768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Edzards, Joshua
A1 - Saßnick, Holger-Dietrich
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Valencia, Ana M.
A1 - Emmerling, Franziska
A1 - Beyer, Sebastian
A1 - Cocchi, Caterina
T1 - Effects of Ligand Substituents on the Character of Zn-Coordination in Zeolitic Imidazolate Frameworks
N2 - Due to their favorable properties and high porosity, zeolitic imidazolate frameworks (ZIFs) have recently received much limelight for key technologies such as energy storage, optoelectronics, sensorics, and catalysis. Despite widespread interest in these materials, fundamental questions regarding the zinc coordination environment remain poorly understood. By focusing on zinc(II)2-methylimidazolate (ZIF-8) and its tetrahedrally coordinated analogues with Br-, Cl-, and H-substitution in the 2-ring position, we aim to clarify how variations in the local environment of Zn impact the charge distribution and the electronic properties of these materials. Our results from densityfunctional theory confirm the presence of a Zn coordinative bond with a large polarization that is quantitatively affected by different substituents on the organic ligand. Moreover, our findings suggest that the variations in the Zn coordination induced by the functionalization have a negligible effect on the electronic structure of the considered compounds. On the other hand, halogen terminations of the ligands lead to distinct electronic contributions in the vicinity of the frontier region which ultimately reduce the band gap size by a few hundred millielectron volts. Experimental results obtained from X-ray absorption spectroscopy (Zn K-edge) confirm the trends predicted by theory and, together with them, contribute to a better understanding of the structure−property relationships that are needed to tailor ZIFs for target applications.
KW - Surfaces
KW - Physical and Theoretical Chemistry
KW - General Energy
KW - Electronic
KW - Coatings and Films
KW - Optical and Magnetic Materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589117
DO - https://doi.org/10.1021/acs.jpcc.3c06054
SN - 1932-7447
VL - 127
IS - 43
SP - 21456
EP - 21464
PB - American Chemical Society (ACS)
AN - OPUS4-58911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Mundra, Shishir
A1 - Henning, Ricky
T1 - Chloride binding by layered double hydroxides (LDH/AFm phases) and alkali-activated slag pastes: an experimental study by RILEM TC 283-CAM
N2 - Chloride binding by the hydrate phases of cementitious materials influences the rate of chloride ingress into these materials and, thus, the time at which chloride reaches the steel reinforcement in concrete structures. Chloride binding isotherms of individual hydrate phases would be required to model chloride ingress but are only scarcely available and partly conflicting. The present study by RILEM TC 283-CAM ‘Chloride transport in alkali-activated materials’ significantly extends the available database and resolves some of the apparent contradictions by determining the chloride binding isotherms of layered double hydroxides (LDH), including AFm phases (monosulfate, strätlingite, hydrotalcite, and meixnerite), and of alkali-activated slags (AAS) produced with four different activators (Na2SiO3, Na2O·1.87SiO2, Na2CO3, and Na2SO4), in NaOH/NaCl solutions at various liquid/solid ratios. Selected solids after chloride binding were analysed by X-ray diffraction, and thermodynamic modelling was applied to simulate the phase changes occurring during chloride binding by the AFm phases. The results of the present study show that the chloride binding isotherms of LDH/AFm phases depend strongly on the liquid/solid ratio during the experiments. This is attributed to kinetic restrictions, which are, however, currently poorly understood. Chloride binding by AAS pastes is only moderately influenced by the employed activator. A steep increase of the chloride binding by AAS occurs at free chloride concentrations above approx. 1.0 M, which is possibly related to chloride binding by the C–(N–)A–S–H gel in the AAS.
KW - Chloride binding
KW - Sorption isotherm
KW - Layered double hydroxide
KW - AFm phase
KW - Alkali-activated materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599370
DO - https://doi.org/10.1617/s11527-024-02311-3
SN - 1359-5997
SN - 1871-6873
VL - 57
IS - 4
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-59937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - Kneiske, Sönke
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Ahrens, Mike
A1 - Braun, Thomas
A1 - Emmerling, Franziska
T1 - A fluorolytic sol-gel route to access an amorphous Zr fluoride catalyst: A useful tool for C-F bond activation
N2 - A route to a ZrF4 catalyst active in room temperature Friedel–Crafts and dehydrofluorination reactions was developed via a fluorolytic sol–gel route, which was followed by a postfluorination step using a stream of CHClF2. The behaviour of different Zr(IV) precursors in a sol–gel reaction with anhydrous isopropanol/HF solution was investigated. The subsequent post-fluorination step was optimised in its temperature ramp and confirmed the necessity of a fluorination of the generated xerogels to obtain catalytic activity. The process is discussed in the context of the analysis of the materials using Brunauer–Emmett–Teller analysis (BET), powder X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The local structure of the amorphous catalyst was elucidated by extended X-ray absorption fine structure spectroscopy (EXAFS).
KW - Catalysis
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - Postfluorination
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593433
DO - https://doi.org/10.1039/D3CY01439H
SN - 2044-4761
SP - 1
EP - 8
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - C. Pardo Pérez, L.
A1 - Arndt, A.
A1 - Stojkovikj, S.
A1 - Y. Ahmet, I.
A1 - T. Arens,, J.
A1 - Dattila, F.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Davies, V.
A1 - Höflich, K.
A1 - Köhnen, E.
A1 - Tockhorn, P.
A1 - Golnak, R.
A1 - Xiao, J.
A1 - Schuck, G.
A1 - Wollgarten, M.
A1 - López, N.
A1 - T. Mayer, M.
T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy
N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts.
KW - Electrochemical CO2 conversion
KW - Cu catalysts
KW - X-ray absorption spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116
DO - https://doi.org/10.1002/aenm.202103328
SN - 1614-6832
VL - 12
IS - 5
SP - 2103328
PB - Wiley-VCH GmbH
AN - OPUS4-54711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunkel, B.
A1 - Kabelitz, Anke
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wohlrab, S.
T1 - Increasing the Efficiency of Optimized V-SBA-15 Catalysts in the Selective Oxidation of Methane to Formaldehyde by Artificial Neural Network Modelling
N2 - The present study investigates the possibility of improving the selective oxidation of methane to formaldehyde over V-SBA-15 catalysts in two different ways. In a classical approach of catalyst optimization, the in situ synthesis of V-SBA-15 catalysts was optimized with regard to the applied pH value. Among the set of catalysts synthesized, a higher amount of incorporated vanadium, a higher content of polymeric VOx species as well as a less ordered structure of the support material were observed by increasing the pH values from 2.0 to 3.0. An optimum in performance during the selective oxidation of methane to formaldehyde with respect to activity and selectivity was found over V-SBA-15 prepared at a pH value of 2.5. With this knowledge, we have now evaluated the possibilities of reaction control using this catalyst. Specifically, artificial neural network modelling was applied after the collection of 232 training samples for obtaining insight into the influence of different reaction parameters (temperature; gas hourly space velocity (GHSV); and concentration of O2, N2 and H2O) onto methane conversion and selectivity towards formaldehyde.
This optimization of reaction conditions resulted in an outstanding high space-time yield of 13.6 kgCH2O∙kgcat∙h−1
KW - Artificial neural network modelling
KW - Selective oxidation
KW - Molecular VOx catalysts
KW - Formaldehyde
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517420
DO - https://doi.org/10.3390/catal10121411
VL - 10
IS - 12
SP - 1411
PB - MDPI
AN - OPUS4-51742
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winnefeld, F.
A1 - Gluth, Gregor
A1 - Bernal, S. A.
A1 - Bignozzi, M. C.
A1 - Carabba, L.
A1 - Chithiraputhiran, S.
A1 - Dehghan, A.
A1 - Dolenec, S.
A1 - Dombrowski-Daube, K.
A1 - Dubey, A.
A1 - Ducman, V.
A1 - Yu, J.
A1 - Peterson, K.
A1 - Stephan, D.
A1 - Provis, J. L.
T1 - RILEM TC 247-DTA round robin test: sulfate resistance, alkali-silica reaction and freeze–thaw resistance of alkali-activated concretes
N2 - The RILEM technical committee TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ conducted a round robin testing programme to determine the validity of various durability testing methods, originally developed for Portland cement based-concretes, for the assessment of the durability of alkali-activated concretes. The outcomes of the round robin tests evaluating sulfate resistance, alkali-silica reaction (ASR) and freeze–thaw resistance are presented in this contribution. Five different alkali-activated concretes, based on ground granulated blast furnace slag, fly ash, or metakaolin were investigated. The extent of sulfate damage to concretes based on slag or fly ash seems to be limited when exposed to an Na2SO4 solution. The mixture based on metakaolin showed an excessive, very early expansion, followed by a dimensionally stable period, which cannot be explained at present. In the slag-based concretes, MgSO4 caused more expansion and visual damage than Na2SO4; however, the expansion limits defined in the respective standards were not exceeded. Both the ASTM C1293 and RILEM AAR-3.1 test methods for the determination of ASR expansion appear to give essentially reliable identification of expansion caused by highly reactive aggregates. Alkali-activated materials in combination with an unreactive or potentially expansive aggregate were in no case seen to cause larger expansions; only the aggregates of known very high reactivity were seen to be problematic. The results of freeze–thaw testing (with/without deicing salts) of alkali-activated concretes suggest an important influence of the curing conditions and experimental conditions on the test outcomes, which need to be understood before the tests can be reliably applied and interpreted.
KW - Alkali-activated materials
KW - Sulfate attack
KW - Alkali silica reaction
KW - Alkali aggregate reaction
KW - Freeze-thaw attack
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515527
DO - https://doi.org/10.1617/s11527-020-01562-0
VL - 53
IS - 6
SP - 140
PB - Springer Nature
AN - OPUS4-51552
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mundra, Shishir
A1 - Provis, J. L.
T1 - Mechanisms of passivation and chloride-induced corrosion of mild steel in sulfide-containing alkaline solutions
N2 - The pore fluid within many concretes is highly alkaline and rich in reduced sulfur species, but the influence of such alkaline-sulfide solutions on the surface film formed on steel reinforcement is poorly understood. This study investigates the critical role of HS− in defining mild steel passivation chemistry. The surface film formed on the steel in alkaline-sulfide solutions contains Fe(OH)2 and Fe–S complexes, and the critical chloride concentration to induce corrosion increases at high sulfide concentration. However, this behavior is dependent on the duration of exposure of the steel to the electrolyte, and the nature of the sulfidic surface layer.
KW - Alkali-activated materials
KW - Steel corrosion
KW - Sulfide
KW - Chloride
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528861
DO - https://doi.org/10.1007/s10853-021-06237-x
VL - 56
IS - 26
SP - 14783
EP - 14802
PB - Springer Nature
AN - OPUS4-52886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Arbi, K.
A1 - Bernal, S. A.
A1 - Bondar, D.
A1 - Castel, A.
A1 - Chithiraputhiran, S.
A1 - Dehghan, A.
A1 - Dombrowski-Daube, K.
A1 - Dubey, A.
A1 - Ducman, V.
A1 - Peterson, K.
A1 - Pipilikaki, P.
A1 - Valcke, S. L. A.
A1 - Ye, G.
A1 - Zuo, Y.
A1 - Provis, J. L.
T1 - RILEM TC 247-DTA round robin test: carbonation and chloride penetration testing of alkali-activated concretes
N2 - Many standardised durability testing methods have been developed for Portland cement-based concretes, but require validation to determine whether they are also applicable to alkali-activated materials. To address this question, RILEM TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ carried out round robin testing of carbonation and chloride penetration test methods, applied to five different alkali-activated concretes based on fly ash, blast furnace slag or metakaolin. The methods appeared overall to demonstrate an intrinsic precision comparable to their precision when applied to conventional concretes. The ranking of test outcomes for pairs of concretes of similar binder chemistry was satisfactory, but rankings were not always reliable when comparing alkali-activated concretes based on different precursors. Accelerated carbonation testing gave similar results for fly ash-based and blast furnace slag-based alkali-activated concretes, whereas natural carbonation testing did not. Carbonation of concrete specimens was observed to have occurred already during curing, which has implications for extrapolation of carbonation testing results to longer service life periods. Accelerated chloride penetration testing according to NT BUILD 443 ranked the tested concretes consistently, while this was not the case for the rapid chloride migration test. Both of these chloride penetration testing methods exhibited comparatively low precision when applied to blast furnace slag-based concretes which are more resistant to chloride ingress than the other materials tested.
KW - Alkali-activated materials
KW - Durability
KW - Carbonation
KW - Chloride penetration
KW - Concrete
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504045
DO - https://doi.org/10.1617/s11527-020-1449-3
SN - 1359-5997
SN - 1871-6873
VL - 53
IS - 1
SP - 21
PB - Springer Nature
AN - OPUS4-50404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Sebastian
A1 - Gluth, Gregor
ED - Rossignol, S.
ED - Gluth, Gregor
T1 - Unraveling the hardening mechanism during laser-induced slip casting of lithium aluminate-microsilica slurry
N2 - Additive manufacturing (AM) of alkali-activated materials is a promising method for producing ceramic precursors, construction elements and other parts. A recently introduced AM process is laser-induced slip casting of lithium aluminate/microsilica slurries, which yields parts with excellent mechanical strengths. To clarify the underlying mechanisms, μ-Raman spectroscopy was applied to parts produced by the process, and the dissolution and hydration of lithium aluminate was studied inter alia using conventional and in-situ X-ray diffraction. The results show that significant dissolution of lithium aluminate occurs, particularly at increased temperatures during laser interaction, which leads to an increase of pH and precipitation of an akopovaite-like Li-Al-CO3 layered double hydroxide. The increase of the pH is likely to induce dissolution of the microsilica and possibly formation of a hydrous lithium aluminosilicate gel. These observations explain the strength evolution of the studied parts and can also aid the development and improvement of related AM methods.
KW - Alkali-activated materials
KW - Additive manufacturing
KW - Laser-induced slip casting
KW - Lithium
KW - Layered double hydroxide
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520557
DO - https://doi.org/10.1016/j.oceram.2021.100060
SN - 2666-5395
VL - 5
IS - Special issue: Alkali-activated materials and geopolymers in ceramics and beyond
SP - 1
EP - 7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-52055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sturm, Patrick
A1 - Moye, J.
A1 - Gluth, Gregor
A1 - Vogler, Nico
A1 - Taffe, A.
A1 - Kühne, Hans-Carsten
ED - Rossignol, S.
ED - Gluth, Gregor
T1 - Properties of alkali-activated mortars with salt aggregate for sealing structures in evaporite rock
N2 - Concrete structures for sealing of tunnels in the host rock are an essential part of systems for nuclear waste storage. However, concretes based on blended cements or magnesium oxychloride cements, which are commonly considered for this application, can deteriorate severely due to a significant heat of hydration and associated deformation and cracking. Alkali-activated materials (AAMs) offer a potential solution to this problem because of their low heat release during hardening. To explore their suitability for the construction of sealing structures in evaporite rock, various AAMs with salt aggregate were studied regarding fresh properties, heat release, mechanical properties and microstructure. The heat of reaction of the AAMs was up to 55% lower than that of a blended cement designed for sealing structures, indicating significant benefits for the intended application. Other relevant properties such as mechanical strength and permeability depended strongly on the mix-design of the AAMs and curing conditions.
KW - Alkali-activated materials
KW - Geopolymers
KW - Nuclear waste storage
KW - Sealing structures
KW - Evaporite rock
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519422
DO - https://doi.org/10.1016/j.oceram.2020.100041
SN - 2666-5395
VL - 5
IS - Special issue: Alkali-activated materials and geopolymers in ceramics and beyond
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-51942
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lumpe, H.
A1 - Menke, Annika
A1 - Haisch, C.
A1 - Mayer, P.
A1 - Kabelitz, Anke
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Block, T.
A1 - Pöttgen, R.
A1 - Emmerling, Franziska
A1 - Daumann, L.
T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled plasma mass spectrometry (ICP‐MS), infrared (IR) spectroscopy, 151Eu‐Mössbauer spectroscopy, X‐ray total scattering, and extended X‐ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
KW - PQQ
KW - Lanthanoide
KW - Coordination chemistry
KW - Rare earth elements separations
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512707
DO - https://doi.org/10.1002/chem.202002653
VL - 26
IS - 44
SP - 10133
EP - 10139
AN - OPUS4-51270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radtke, Martin
A1 - Rakotondrajoa, A.
T1 - Machine learning based quantification of synchrotron radiation-induced X-ray fluorescence measurements - a case study
N2 - In this work, we describe the use of artificial neural networks for the quantification of X-ray fluorescence measurements. The training data were generated using Monte Carlo simulation, which avoided the use of adapted reference materials. The extension of the available data set by means of an ANN to generate additional data was demonstrated. Particular emphasis was put on the comparability of simulated and experimental data and how the influence of deviations can be reduced. The search for the optimal hyperparameter, manual and automatic, is also described. For the presented case, we were able to train a network with a mean absolute error of 0.1 weight percent for the synthetic data and 0.7 weight percent for a set of experimental data obtained with certified reference materials.
KW - Machine learning
KW - BAMline
KW - XRF
KW - Synchrotron
KW - Neural network
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519008
DO - https://doi.org/10.1088/2632-2153/abc9fb
SP - 1
EP - 16
PB - IOP Publishing
AN - OPUS4-51900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hüsken, Götz
A1 - Wagner, L.-C.
A1 - Gluth, Gregor
A1 - Pirskawetz, Stephan
A1 - Kühne, Hans-Carsten
T1 - Application of Steel Fibres in Alkali-Activated Mortars
N2 - Alkali-activated materials are ideal for the repair of concrete structures in harsh environmental conditions due to their high durability in chemically aggressive environments. However, slag-based mortars, in particular, are prone to shrinkage and associated cracks. In this respect, the application of steel fibres is one solution to reduce the formation of shrinkage induced cracks and to improve post cracking behaviour of these mortars. This study investigated the influence of two different types of steel fibres on the tensile properties of two alkali-activated mortars. Direct tensile tests and single fibre pull-outs were performed to analyse the determining failure modes both on macro and micro scale. Mechanical testing was accompanied by non-destructive testing methods such as digital image correlation and acoustic emission for a detailed analysis of the fracture process.
T2 - Local Mechanical Properties - LMP 2019
CY - Prague, Czech Republic
DA - 06.11.2019
KW - Alkali-activated materials
KW - Fibre pull-out
KW - Steel fibres
KW - Tensile strength
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509291
UR - https://ojs.cvut.cz/ojs/index.php/APP/article/view/6695
DO - https://doi.org/10.14311/APP.2020.27.0090
VL - 27
SP - 90
EP - 95
CY - Prague, Czech Republic
AN - OPUS4-50929
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Taylor, J.
A1 - Thakur, S.
A1 - Radu, F.
A1 - Weschke, E.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Xiao, B.
A1 - Savan, A.
A1 - Yusenko, Kirill
A1 - Ludwig, A.
T1 - Local structure and magnetic properties of a nanocrystalline Mn-rich Cantor alloy thin film down to the atomic scale
N2 - The huge atomic heterogeneity of high-entropy materials along with a possibility to unravel the behavior of individual components at the atomic scale suggests a great promise in designing new compositionally complex systems with the desired multi-functionality. Herein, we apply multi-edge X-ray absorption spectroscopy (extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and X-ray magnetic circular dichroism (XMCD)) to probe the structural, electronic, and magnetic properties of all individual constituents in the single-phase face-centered cubic (fcc)-structured nanocrystalline thin film of Cr20Mn26Fe18Co19Ni17 (at.%) high-entropy alloy on the local scale. The local crystallographic ordering and component-dependent lattice displacements were explored within the reverse Monte Carlo approach applied to EXAFS spectra collected at the K absorption edges of several constituents at room temperature. A homogeneous short-range fcc atomic environment around the absorbers of each type with very similar statistically averaged interatomic distances (2.54–2.55 Å) to their nearest-neighbors and enlarged structural relaxations of Cr atoms were revealed. XANES and XMCD spectra collected at the L2,3 absorption edges of all principal components at low temperature from the oxidized and in situ cleaned surfaces were used to probe the oxidation states, the changes in the electronic structure, and magnetic behavior of all constituents at the surface and in the sub-surface volume of the film. The spin and orbital magnetic moments of Fe, Co, and Ni components were quantitatively evaluated. The presence of magnetic phase transitions and the co-existence of different magnetic phases were uncovered by conventional magnetometry in a broad temperature range.
KW - Magnetism
KW - High-entropy alloys
KW - Reverse Monte Carlo (RMC)
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS),
KW - X-ray magnetic circular dichroism (XMCD),
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578254
DO - https://doi.org/10.1007/s12274-022-5135-3
SN - 1998-0124
SP - 5626
PB - Springer
AN - OPUS4-57825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rudić, O.
A1 - Mittermayr, F.
A1 - Gluth, Gregor
A1 - Simon, Sebastian
A1 - Ukrainczyk, N.
A1 - Seyrek, Y.
A1 - Freytag, B.
A1 - Juhart, J.
A1 - Grengg, C.
T1 - On the benefits of vegetable oil addition for the pore structure and acid resistance of alkali-activated systems
N2 - The impact of high additions of vegetable oil (12 vol%) on the mechanical and microstructural properties of metakaolin-slag-based alkali-activated materials (AAMs) was studied. The addition of oil resulted in a slight decrease in initial polymerization kinetics but did not affect the final degree of reaction. AAM-oil-composite-mortars exhibited approximately ∼30% lower compressive strength primarily due to the entrainment of air voids. Newly formed soap phases significantly reduced the volume of small capillary and gel pores (pore radii <15 nm), leading to a decrease in specific inner surface area by a factor of up to 15. The porosity modification induced by the oil addition greatly enhanced the resistance of AAMs against sulfuric acid attack, shifting the dominant processes from diffusion and cracks to framework-dissolution controlled by the inherent phase stabilities. Following the immersion in sulfuric acid (pHstat = 2) for 8 weeks, the depth of corroded layer decreased by 70% and no cracks due to expansive phases were observed. These promising findings suggest that the incorporation of vegetable oil in AAMs has the potential to address durability concerns associated with diffusion-based corrosion processes, thereby expanding the range of future applications.
KW - Alkali-activated materials
KW - Acid resistance
KW - Pore structure
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581719
DO - https://doi.org/10.1016/j.ceramint.2023.08.036
VL - 49
IS - 20
SP - 33275
EP - 33290
PB - Elsevier Ltd.
AN - OPUS4-58171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mundra, S.
A1 - Samson, G.
A1 - Masi, G.
A1 - Achenbach, R.
A1 - Bastidas, D. M.
A1 - Bernal, S. A.
A1 - Bignozzi, M. C.
A1 - Criado, M.
A1 - Cyr, M.
A1 - Gartner, N.
A1 - von Greve-Dierfeld, S.
A1 - Legat, A.
A1 - Nikoonasab, Ali
A1 - Provis, J. L.
A1 - Raupach, M.
A1 - Gluth, Gregor
T1 - Application of electrochemical methods for studying steel corrosion in alkali-activated materials
N2 - Alkali-activated materials (AAMs) are binders that can complement and partially substitute the current use of conventional cement. However, the present knowledge about how AAMs protect steel reinforcement in concrete elements is incomplete, and uncertainties exist regarding the application of electrochemical methods to investigate this issue. The present review by EFC WP11-Task Force ‘Corrosion of steel in alkali-activated materials’ demonstrates that important differences exist between AAMs and Portland cement, and between different classes of AAMs, which are mainly caused by differing pore solution compositions, and which affect the outcomes of electrochemical measurements. The high sulfide concentrations in blast furnace slag-based AAMs lead to distinct anodic polarisation curves, unusually low open circuit potentials, and low polarisation resistances, which might be incorrectly interpreted as indicating active corrosion of steel reinforcement. No systematic study of the influence of the steel–concrete interface on the susceptibility of steel to corrosion in AAMs is available. Less common electrochemical methods present an opportunity for future progress in the field.
KW - Alkali-activated materials
KW - Reinforcement corrosion
KW - Steel corrrosion
KW - Electrochemical methods
KW - Concrete
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572241
DO - https://doi.org/10.1002/maco.202313743
SN - 1521-4176
VL - 74
IS - 7
SP - 988
EP - 1008
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-57224
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, Stefan
A1 - Kunkel, Benny
A1 - Cakir, Cafer Tufan
A1 - Kabelitz, Anke
A1 - Witte, Steffen
A1 - Bernstein, Thomas
A1 - Bartling, Stephan
A1 - Radtke, Martin
A1 - Emmerling, Franziska
A1 - Abdel-Mageed, Ali Mohamed
A1 - Wohlrab, Sebastian
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time-, space- and energy-resolved in situ characterization of catalysts by X-ray absorption spectroscopy
N2 - A novel setup for dispersive X-ray absorption spectroscopy (XAS) with simultaneous resolution of space, time and energy for in situ characterization of solid materials is demonstrated.
KW - Dispersive XAS
KW - Catalysis
KW - In situ
KW - Structure analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584924
DO - https://doi.org/10.1039/d3cc03277a
SN - 1359-7345
SP - 1
EP - 4
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Ryll, T. W.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz Maciej
T1 - Phase stability studies on transition metal phosphates aided by an automated synthesis
N2 - Transition metal phosphates (TMPs) have attracted interest as materials for (electro-) catalysis, and electrochemistry due to their low-cost, stability, and tunability. In this work, an automated synthesis platform was used for the preparation of transition metal phosphate crystals to efficiently explore the multidimensional parameter space, determining the phase selection, crystal sizes, shapes. By using X-ray diffraction and spectroscopy-based methods and electron microscopy imaging, a complete characterization of the phase stability fields, phase transitions, and crystal morphology/sizes was achieved. In an automated three-reactant synthesis, the individual effect of each reactant species NH4+, M2+, and PO43- on the formation of transition metal phosphate phases: M-struvite NH4MPO4·6H2O, M-phosphate octahydrate M3(PO4)2·8H2O with M = Ni, Co and an amorphous phase, was investigated. The NH4+ concentration dictates the phase composition, morphology, and particle size in the Ni-system (crystalline Ni-struvite versus amorphous Ni-PO4 phase), whereas in the Co-system all reactant species - NH4+, Co2+, and PO43- - influence the reaction outcome equivalently (Co-struvite vs. Co-phosphate octahydrate). The coordination environment for all crystalline compounds and of the amorphous Ni-PO4 phase was resolved by X-ray absorption spectroscopy, revealing matching characteristics to its crystalline analogue, Ni3(PO4)2·8H2O. The automated synthesis turned out to be significantly advantageous for the exploration of phase diagrams due to its simple modularity, facile traceability, and enhanced reproducibility compared to a typical manual synthesis.
KW - Automated synthesis
KW - Phase diagrams
KW - Transition metals
KW - Phosphates
KW - Local structure
KW - Struvite
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579151
DO - https://doi.org/10.1039/D3CE00386H
VL - 25
IS - 30
SP - 4333
EP - 4344
PB - CrystEngComm
CY - London
AN - OPUS4-57915
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Cakir, Cafer Tufan
A1 - Radtke, Martin
A1 - Haider, M. Bilal
A1 - Emmerling, Franziska
A1 - F. M. Oliveira, P.
A1 - Michalchuk, Adam
T1 - Dispersive x-ray absorption spectroscopy for time-resolved in situ monitoring of mechanochemical reactions
N2 - X-ray absorption spectroscopy (XAS) provides a unique, atom-specific tool to probe the electronic structure of solids. By surmounting long-held limitations of powder-based XAS using a dynamically averaged powder in a Resonant Acoustic Mixer (RAM), we demonstrate how time-resolved in situ (TRIS) XAS provides unprecedented detail of mechanochemical synthesis. The use of a custom-designed dispersive XAS (DXAS) setup allows us to increase the time resolution over existing fluorescence measurements from ∼15 min to 2 s for a complete absorption spectrum. Hence, we here establish TRIS-XAS as a viable method for studying mechanochemical reactions and sampling reaction kinetics. The generality of our approach is demonstrated through RAM-induced (i) bottom-up Au nanoparticle mechanosynthesis and (ii) the synthesis of a prototypical metal organic framework, ZIF-8. Moreover, we demonstrate that our approach also works with the addition of a stainless steel milling ball, opening the door to using TRIS-DXAS for following conventional ball milling reactions. We expect that our TRIS-DXAS approach will become an essential part of the mechanochemical tool box.
KW - In situ studies
KW - Dipsersive XAS
KW - Mechanochemistry
KW - Time-resolved
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567659
DO - https://doi.org/10.1063/5.0130673
SN - 1089-7690
VL - 157
IS - 21
SP - 1
EP - 12
PB - American Institute of Physics
CY - Melville, NY
AN - OPUS4-56765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Ahrens, M.
A1 - Braun, T.
A1 - Emmerling, Franziska
T1 - An amorphous Lewis-acidic zirconium chlorofluoride as HF shuttle: C–F bond activation and formation
N2 - An exceptional HF transfer reaction by C–F bond activation of fluoropentane and a subsequent hydrofluorination of alkynes at room temperature is reported. An amorphous Lewis-acidic Zr chlorofluoride serves as heterogeneous catalyst, which is characterised by an eightfold coordination environment at Zr including chlorine atoms. The studies are seminal in establishing sustainable fluorine chemistry.
KW - ZCF
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - HF-shuttle
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582249
DO - https://doi.org/10.1039/D3CC03164K
SN - 1359-7345
VL - 59
IS - 75
SP - 11224
EP - 11227
PB - RSC
CY - Cambridge
AN - OPUS4-58224
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vollpracht, A.
A1 - Gluth, Gregor
A1 - Rogiers, B.
A1 - Uwanuakwa, I. D.
A1 - Phung, Q. T.
A1 - Villagran Zaccardi, Y.
A1 - Thiel, C.
A1 - Vanoutrive, H.
A1 - Etcheverry, J. M.
A1 - Gruyaert, E.
A1 - Kamali-Bernard, S.
A1 - Kanellopoulos, A.
A1 - Zhao, Z.
A1 - Martins, I. M.
A1 - Rathnarajan, S.
A1 - De Belie, N.
T1 - Report of RILEM TC 281-CCC: insights into factors affecting the carbonation rate of concrete with SCMs revealed from data mining and machine learning approaches
N2 - The RILEM TC 281–CCC ‘‘Carbonation of concrete with supplementary cementitious materials’’ conducted a study on the effects of supplementary cementitious materials (SCMs) on the carbonation rate of blended cement concretes and mortars. In this context, a comprehensive database has been established, consisting of 1044 concrete and mortar mixes with their associated carbonation depth data over time. The dataset comprises mix designs with a large variety of binders with up to 94% SCMs, collected from the literature as well as unpublished testing reports. The data includes chemical composition and physical properties of the raw materials, mix-designs, compressive strengths, curing and carbonation testing conditions. Natural carbonation was recorded for several years in many cases with both indoor and outdoor results. The database has been analysed to investigate the effects of binder composition and mix design, curing and preconditioning, and relative humidity on the carbonation rate. Furthermore, the accuracy of accelerated carbonation testing as well as possible correlations between compressive strength and carbonation resistance were evaluated. One approach to summerise the physical and chemical resistance in one parameter is the ratio of water content to content of carbonatable CaO (w/CaOreactive ratio). The analysis revealed that the w/CaOreactive ratio is a decisive factor for carbonation resistance, while curing and exposure conditions also influence carbonation. Under natural exposure conditions, the carbonation data exhibit significant variations. Nevertheless, probabilistic inference suggests that both accelerated and natural carbonation processes follow a square-root-of-time behavior, though accelerated and natural carbonation cannot be converted into each other without corrections. Additionally, a machine learning technique was employed to assess the influence of parameters governing the carbonation progress in concretes.
KW - Carbonation
KW - Supplementary cementitious materials
KW - Concrete
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614388
DO - https://doi.org/10.1617/s11527-024-02465-0
SN - 1871-6873
SN - 1359-5997
VL - 57
IS - 9
SP - 1
EP - 33
PB - Springer Nature
AN - OPUS4-61438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Coburger, Peter
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
A1 - Abbenseth, Josh
T1 - Combining geometric constraint and redox non-innocence within an ambiphilic PBiP pincer ligand
N2 - The first pincer ligand featuring a strictly T-shaped pnictogen donor moiety was synthesised. The PBiP ligand's redox activity facilitates unprecedented ambiphilic bonding of the Bi centre with transition metals through the Bi(6p) orbital.
KW - EXAFS
KW - Pincer Ligand
KW - Group 15 metals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611113
DO - https://doi.org/10.1039/D4SC00197D
SN - 2041-6520
SP - 1
EP - 8
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61111
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lima, G. T. S.
A1 - Silvestro, L.
A1 - Durlo Tambara, Luís Urbano
A1 - Cheriaf, M.
A1 - Rocha, J. C.
T1 - Autonomous Self-Healing Agents in Cementitious Materials: Parameters and Impacts on Mortar Properties
N2 - The concept of self-healing materials and the development of encapsulated curing agents represent a cutting-edge approach to enhancing the longevity and reducing the maintenance costs of cementitious structures. This systematic literature review aims to shed light on the parameters involved in the autonomous self-healing of cementitious materials, utilizing various encapsulated healing agents such as pellets, granules, and capsules. This review also identifies and selects studies that offer additional insights into the efficacy of the self-healing process in cementitious materials and the influence of these specific encapsulated healing agents on the physical mechanical properties of mortars. This comprehensive approach provides a deep understanding of the interplay between self-healing and the physical–mechanical properties of mortars containing these encapsulated healing agents. The main findings indicate that the cement-to-sand ratio, characteristics of fine aggregates, and encapsulation methods significantly impact crack control, self-healing efficiency, and properties of mortar in both fresh and hardened states. The content of encapsulated healing agents within the cementitious matrix affects both the initial workability or flow and subsequent mechanical properties. While pellets coated with PVA film typically reduce workability in the fresh state and compressive strength, capsules coated with Portland cement and sodium silicate mitigate these effects and improve crack sealing in fresh and hardened states without compromising the self-healing capacity of cracks. The three-point flexural test has emerged as the preferred method for a pre-crack assessment over 28 days, with variations depending on the type of healing agent used. As noted in the literature, water has been identified as the optimal environment for autonomous healing. These findings underscore the potential of encapsulation techniques to enhance self-healing capabilities through the controlled release of agents within the cementitious matrix, thereby advancing the research on and development of intelligent construction materials and increasing the durability of cement-based structures.
KW - Self-healing cementitious composite
KW - Encapsulated curing agents
KW - Pellets
KW - Granules
KW - Capsules
KW - Physical–mechanical properties
KW - Autonomous self-healing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611860
DO - https://doi.org/10.3390/buildings14072000
SN - 2075-5309
VL - 14
IS - 7
SP - 1
EP - 23
PB - MDPI
CY - Basel
AN - OPUS4-61186
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tu, Z.
A1 - Donskyi, Ievgen
A1 - Qiao, H.
A1 - Zhu, Z.
A1 - Unger, Wolfgang
A1 - Hackenberger, C. P. R.
A1 - Chen, W.
A1 - Adeli, M.
A1 - Haag, R.
T1 - Graphene Oxide-Cyclic R10 Peptide Nuclear Translocation Nanoplatforms for the Surmounting of Multiple-Drug Resistance
N2 - Multidrug resistance resulting from a variety of defensive pathways in Cancer has become a global concern with a considerable impact on the mortality associated with the failure of traditional chemotherapy. Therefore, further research and new therapies are required to overcome this challenge. In this work, a cyclic R10 peptide (cR10) is conjugated to polyglycerol-covered nanographene oxide to engineer a nanoplatform for the surmounting of multidrug resistance. The nuclear translocation of the nanoplatform, facilitated by cR10 peptide, and subsequently, a laser-triggered release of the loaded doxorubicin result in efficient anticancer activity confirmed by both in vitro and in vivo experiments. The synthesized nanoplatform with a combination of different features, including active nucleus-targeting, highloading capacity, controlled release of cargo, and photothermal property, provides a new strategy for circumventing multidrug resistant cancers.
KW - Graphen Oxide
KW - Nanoplatform
KW - Cancer
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510061
DO - https://doi.org/10.1002/adfm.202000933
VL - 30
IS - 35
SP - 2000933
PB - Wiley VCH
AN - OPUS4-51006
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kulka, M.W.
A1 - Nie, C.
A1 - Nickl, P.
A1 - Kerkhoff, Y.
A1 - Garg, A.
A1 - Salz, D.
A1 - Radnik, Jörg
A1 - Grunwald, I.
A1 - Haag, R.
T1 - Surface-Initiated Grafting of Dendritic Polyglycerol from Mussel-Inspired Adhesion-Layers for the Creation of Cell-Repelling Coatings
N2 - Biofouling is a major challenge in the application of textiles, biosensors, and biomedical implants. In the current work, a straightforward method for the solvent-free polymerization of antifouling dendritic polyglycerol (dPG) from mussel-inspired dendritic polyglycerol (MI-dPG) coatings on hydrophilic titanium dioxide (TiO2) and hydrophobic polydimethylsiloxane (PDMS) is reported. Surface characterization is performed by static water contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Significant lower CA values are obtained after dPG grafting from MI-dPG-coated TiO2 and MI-dPG coated PDMS. Furthermore, XPS shows a time-dependent increase of the CO bond content upon dPG grafting from MI-dPG-coated TiO2 and MI-dPG-coated PDMS. Analysis of the surface morphology by SEM shows a clear time-dependent increase in the surface roughness upon dPG grafting from MI-dPG-coated TiO2 and MIdPG-coated PDMS. When the viability of two adhesive cell types is studied via LIVE/DEAD staining, a strong reduction in the cell density is observed after the dPG grafting from MI-dPG-coated TiO2 and MI-dPG-coated PDMS (a decrease of >95% in all cases). The combined results show that biocompatible but highly cell-repelling surfaces are efficiently constructed via the grafting of dPG from MI-dPG-coated TiO2 and MI-dPG-coated PDMS.
KW - Repelling surface coatings
KW - Dendritic polyglycerol
KW - Mussel-inspired adhesives
KW - Surface-initated grafting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516590
DO - https://doi.org/10.1002/admi.202000931
SN - 2196-7350
VL - 7
IS - 24
SP - 931
PB - Wiley VCH
AN - OPUS4-51659
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weigert, Florian
A1 - Müller, A.
A1 - Häusler, I.
A1 - Geißler, Daniel
A1 - Skroblin, D.
A1 - Unger, Wolfgang
A1 - Radnik, Jörg
A1 - Resch-Genger, Ute
T1 - Combining HR‑TEM and XPS to elucidate the core–shell structure of ultrabright CdSe/CdS semiconductor quantum dots
N2 - Controlling thickness and tightness of surface passivation shells is crucial for many applications of core–shell nanoparticles (NP). Usually, to determine shell thickness, core and core/shell particle are measured individually requiring the availability of both nanoobjects. This is often not fulfilled for functional nanomaterials such as many photoluminescent semiconductor quantum dots (QD) used for bioimaging, solid state lighting, and display technologies as the core does not show the applicationrelevant functionality like a high photoluminescence (PL) quantum yield, calling for a whole nanoobject approach. By combining high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS), a novel whole nanoobject approach is developed representatively for an ultrabright oleic acid-stabilized, thick shell CdSe/CdS QD with a PL quantum yield close to unity. The size of this spectroscopically assessed QD, is in the range of the information depth of usual laboratory XPS. Information on particle size and monodispersity were validated with dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) and compared to data derived from optical measurements. In addition to demonstrating the potential of this novel whole nanoobject approach for determining architectures of small nanoparticles, the presented results also highlight challenges faced by different sizing and structural analysis methods and method-inherent uncertainties.
KW - Photoluminescence
KW - Single particle
KW - Microscopy
KW - Particle architecture
KW - Thickness
KW - SAXS
KW - Shell
KW - XPS
KW - TEM
KW - Semiconductor
KW - Quantum dot
KW - Photophysics
KW - Quantum yield
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517911
DO - https://doi.org/10.1038/s41598-020-77530-z
VL - 10
IS - 1
SP - 20712
PB - Springer Nature
AN - OPUS4-51791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Anja
A1 - Krahl, T.
A1 - Radnik, Jörg
A1 - Wagner, Andreas
A1 - Werner, W. S. M.
A1 - Ritter, B.
A1 - Kemnitz, E.
A1 - Unger, Wolfgang
T1 - Chemical in-depth analysis of (Ca/Sr)F2 core–shell like nanoparticles by X-ray photoelectron spectroscopy with tunable excitation energy
N2 - The fluorolytic sol–gel synthesis is applied with the intention to obtain two different types of core–shell nanoparticles, namely, SrF2–CaF2 and CaF2–SrF2. In two separate fluorination steps for core and shell formation, the corresponding metal lactates are reacted with anhydrous HF in ethylene glycol. Scanning transmission electron microscopy (STEM) and dynamic light scattering (DLS) confirm the formation of particles with mean dimensions between 6.4 and 11.5 nm. The overall chemical composition of the particles during the different reaction steps is monitored by quantitative Al Kα excitation X-ray photoelectron spectroscopy (XPS). Here, the formation of stoichiometric metal fluorides (MF2) is confirmed, both for the core and the final core–shell particles. Furthermore, an in-depth analysis by synchrotron radiation XPS (SR-XPS) with tunable excitation energy is performed to confirm the core–Shell character of the nanoparticles. Additionally, Ca2p/Sr3d XPS intensity ratio in-Depth profiles are simulated using the software Simulation of Electron Spectra for Surface Analysis (SESSA). In principle, core–shell like particle morphologies are formed but without a sharp interface between calcium and strontium containing phases.
Surprisingly, the in-depth chemical distribution of the two types of nanoparticles is equal within the error of the experiment. Both comprise a SrF2-rich core domain and CaF2-rich shell domain with an intermixing zone between them. Consequently, the internal morphology of the final nanoparticles seems to be independent from the synthesis chronology.
KW - Metal fluorides
KW - Sol-gel synthesis
KW - Synchrotron radiation
KW - X-ray photoelectron spectroscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522284
DO - https://doi.org/10.1002/sia.6937
SN - 0142-2421
VL - 53
IS - 5
SP - 494
EP - 508
PB - Wiley VCH
AN - OPUS4-52228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bennet, Francesca
A1 - Müller, Anja
A1 - Radnik, Jörg
A1 - Hachenberger, Y.
A1 - Jungnickel, H.
A1 - Laue, P.
A1 - Luch, A.
A1 - Tentschert, J.
T1 - Preparation of Nanoparticles for ToF-SIMS and XPS Analysis
N2 - Nanoparticles have gained increasing attention in recent years due to their potential and application in different fields including medicine, cosmetics, chemistry, and their potential to enable advanced materials. To effectively understand and regulate the physico-chemical properties and potential adverse effects of nanoparticles, validated measurement procedures for the various properties of nanoparticles need to be developed. While procedures for measuring nanoparticle size and size Distribution are already established, standardized methods for analysis of their surface chemistry are not yet in place, although the influence of the surface chemistry on nanoparticle properties is undisputed. In particular, storage and preparation of nanoparticles for surface analysis strongly influences the analytical results from various methods, and in order to obtain consistent results, sample preparation must be both optimized and standardized. In this contribution, we present, in detail, some standard procedures for preparing nanoparticles for surface analytics. In principle, nanoparticles can be deposited on a suitable substrate from suspension or as a powder. Silicon (Si) Wafers are commonly used as substrate, however, their cleaning is critical to the process. For sample preparation from suspension, we will discuss drop-casting and spin-coating, where not only the cleanliness of the substrate and purity of the suspension but also its concentration play important roles for the success of the preparation methodology.
For nanoparticles with sensitive ligand shells or coatings, deposition as powders is more suitable, although this method requires particular care in fixing the sample.
KW - Titania nanoparticles
KW - X-ray photoelectron spectroscopy
KW - Secondary ion mass spectrometry
KW - Surface chemisttry
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520103
UR - https://www.jove.com/video/61758
DO - https://doi.org/10.3791/61758
VL - 163
SP - e61758
AN - OPUS4-52010
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Donskyi, Ievgen
A1 - Nie, C.
A1 - Ludwig, K.
A1 - Trimpert, J.
A1 - Ahmed, R.
A1 - Quaas, E.
A1 - Achazi, K.
A1 - Radnik, Jörg
A1 - Adeli, M.
A1 - Haag, R.
A1 - Osterrieder, K.
T1 - Graphene Sheets with Defined Dual Functionalities for the Strong SARS-CoV-2 Interactions
N2 - Search of new strategies for the inhibition of respiratory viruses is one of the urgent health challenges worldwide, as most of the current therapeutic agents and treatments are inefficient. Severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) has caused a pandemic and has taken lives of approximately two Million people to date. Even though various vaccines are currently under development, virus, and especially its spike glycoprotein can mutate, which highlights a Need for a broad-spectrum inhibitor. In this work, inhibition of SARS-CoV-2 by graphene platforms with precise dual sulfate/alkyl functionalities is investigated. A series of graphene derivatives with different lengths of aliphatic chains is synthesized and is investigated for their ability to inhibit SARS-CoV-2 and feline coronavirus.
Graphene derivatives with long alkyl chains (>C9) inhibit coronavirus replication by virtue of disrupting viral envelope. The ability of these graphene platforms to rupture viruses is visualized by atomic force microscopy and cryogenic electron microscopy. A large concentration window (10 to 100-fold) where graphene platforms display strongly antiviral activity against native SARS-CoV-2 without significant toxicity against human cells is found. In this concentration range, the synthesized graphene platforms inhibit the infection of enveloped viruses efficiently, opening new therapeutic and metaphylactic avenues against SARS-CoV-2.
KW - Graphene
KW - Graphene-based polyglycerol sulfates
KW - SARS-CoV2 inhibitor
KW - Virucidality
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520858
DO - https://doi.org/10.1002/smll.202007091
VL - 17
IS - 11
SP - 7091
PB - Wiley VCH
AN - OPUS4-52085
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hünger, K.-J.
A1 - Kositz, M.
A1 - Danneberg, M.
A1 - Radnik, Jörg
T1 - Enrichment of aluminium in the near‐surface region of natural quartzite rock after aluminium exposure
N2 - Alkali–silica reaction (ASR) is an ongoing problem that causes damage to concrete constructions and reduces their durability. Therefore, minimizing this undesired reaction is of great interest for both safety and economic reasons. Additives containing high aluminium content are very effective in reducing the release of silica and enhancing the durability of concrete; however, the mechanism for this effect is still under discussion. In this study, an enrichment of aluminium in the near‐surface region was observed for natural quartzite rock after storage in Al (OH)3 and metakaolin as aluminium sources, from which we conclude that the formation of aluminosilicate sheets of a few nanometres inhibits the silica release; this hypothesis is supported by high‐resolution spectra of Al 2p, Si 2p and O 1s.
KW - Alkali-silica reaction
KW - Quartzite rock
KW - X-ray photoelectron spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519394
DO - https://doi.org/10.1002/sia.6918
SN - 0142-2421
SP - 1
EP - 7
PB - Wiley VCH
AN - OPUS4-51939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Knigge, Xenia
A1 - Andresen, Elina
A1 - Resch-Genger, Ute
A1 - Cant, D.J.H.
A1 - Shard, A.G.
A1 - Clifford, C.A.
T1 - Composition, thickness, and homogeneity of the coating of core–shell nanoparticles—possibilities, limits, and challenges of X-ray photoelectron spectroscopy
N2 - Core–shell nanoparticles have attracted much attention in recent years due to their unique properties and their increasing importance in many technological and consumer products. However, the chemistry of nanoparticles is still rarely investigated in comparison to their size and morphology. In this review, the possibilities, limits, and challenges of X-ray photoelectron spectroscopy (XPS) for obtaining more insights into the composition, thickness, and homogeneity of nanoparticle coatings are discussed with four examples: CdSe/CdS quantum dots with a thick coating and a small core; NaYF4-based upconverting nanoparticles with a large Yb-doped core and a thin Er-doped coating; and two types of polymer nanoparticles with a poly(tetrafluoroethylene) core with either a poly(methyl methacrylate) or polystyrene coating. Different approaches for calculating the thickness of the coating are presented, like a simple numerical modelling or a more complex simulation of the photoelectron peaks. Additionally, modelling of the XPS background for the investigation of coating is discussed. Furthermore, the new possibilities to measure with varying excitation energies or with hard-energy X-ray sources (hard-energy X-ray photoelectron spectroscopy) are described. A discussion about the sources of uncertainty for the determination of the thickness of the coating completes this review.
KW - X-ray spectroscopy
KW - Nanoparticles
KW - Spectroscopy / Instrumentation
KW - Spectroscopy / Theory
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548305
DO - https://doi.org/10.1007/s00216-022-04057-9
VL - 414
IS - 15
SP - 4331
EP - 4345
PB - SpringerNature
AN - OPUS4-54830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Gernhard, M.
A1 - Radnik, Jörg
A1 - Witt, Julia
A1 - Roth, C.
A1 - Emmerling, Franziska
T1 - Mechanochemical synthesis of fluorine-containing Co-doped zeolitic imidazolate frameworks for producing electrocatalysts
N2 - Catalysts derived from pyrolysis of metal organic frameworks (MOFs) are promising candidates to replace expensive and scarce platinum-based electrocatalysts commonly used in polymer electrolyte membrane fuel cells. MOFs contain ordered connections between metal centers and organic ligands. They can be pyrolyzed into metal- and nitrogen-doped carbons, which show electrocatalytic activity toward the oxygen reduction reaction (ORR). Furthermore, metal-free heteroatom-doped carbons, such as N-F-Cs, are known for being active as well. Thus, a carbon material with Co-N-F doping could possibly be even more promising as ORR electrocatalyst. Herein, we report the mechanochemical synthesis of two polymorphs of a zeolitic imidazole framework, Co-doped zinc 2-trifluoromethyl-1H-imidazolate (Zn0.9Co0.1(CF3-Im)2). Time-resolved in situ X-ray diffraction studies of the mechanochemical formation revealed a direct conversion of starting materials to the products. Both polymorphs of Zn0.9Co0.1(CF3-Im)2 were pyrolyzed, yielding Co-N-F containing carbons, which are active toward electrochemical ORR.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - Nobel-metal free electrocatalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546833
DO - https://doi.org/10.3389/fchem.2022.840758
SN - 2296-2646
VL - 10
IS - 840758
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-54683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heilmann, Maria
A1 - Prinz, Carsten
A1 - Bienert, Ralf
A1 - Wendt, R.
A1 - Kunkel, B.
A1 - Radnik, Jörg
A1 - Hoell, A.
A1 - Wohlrab, S.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
T1 - Size-Tunable Ni–Cu Core–Shell Nanoparticles—Structure, Composition, and Catalytic Activity for the Reverse Water–Gas Shift Reaction
N2 - A facile and efficient methodology is described for the solvothermal synthesis of size-tunable, stable, and uniform NiCu core–shell nanoparticles (NPs) for application in catalysis. The diameter of the NPs is tuned in a range from 6 nm to 30 nm and to adjust the Ni:Cu ratio from 30:1 to 1:1. Furthermore, the influence of different reaction parameters on the final NPs is studied. The NPs are structurally characterized by a method combination of transmission electron microscopy, anomalous small-angle X-ray scattering, X-ray absorption fine structure, and X-ray photoelectron spectroscopy. Using these analytical methods, it is possible to elucidate a core–shell–shell structure of all particles and their chemical composition. In all cases, a depletion from the core to the shell is observed, with the core consisting of NiCu alloy, surrounded by an inner Ni-rich shell and an outer NiO shell. The SiO2-supported NiCu core–shell NPs show pronounced selectivity of >99% for CO in the catalytic reduction of CO2 to CO using hydrogen as reactant (reverse water–gas shift reaction) independent of size and Ni:Cu ratio.
KW - Nanoparticles
KW - Core-shell
KW - Catalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543606
DO - https://doi.org/10.1002/adem.202101308
SN - 1438-1656
SP - 1
EP - 13
PB - Wiley VCH
AN - OPUS4-54360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodríguez-Sánchez, Noelia
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Prinz, Carsten
A1 - Prieto-Laria, P.
A1 - Ruiz-Salvador, A.R.
A1 - Ballesteros, M.
T1 - Engineering a multivariate cobalt metal–organic framework for high photocatalytic activity: the impact of mixed ligands and metal incorporation in a visible light-driven heterogeneous photo-Fenton reaction for water treatment
N2 - Metal–organic frameworks (MOFs) have attracted increasing attention for the removal of organic pollutants in wastewater via photocatalysis. Here, we design a multivariate modification of ZIF-9 to tune its electronic properties for use in visible light photocatalysis. A controllable synthesis of ZIF-9 and its multivariate forms with the incorporation of copper and the 2-imidazolecarboxaldehyde (ica) ligand was carried out. The materials are tested for the removal of the model dye methylene blue (MB) by a heterogeneous photo-Fenton-like reaction at neutral pH and room temperature. Cu-ZIF-9-ica (UPO-3) shows high photocatalytic activity under both visible and ultraviolet A (UVA) light, achieving 94% MB degradation in 45 min, compared to 65% MB degradation in 120 min using bare ZIF-9. The study revealed a first-order rate constant of 0.0475 min−1 for Cu-ZIF-9-ica compared to 0.0088 min−1 for ZIF-9 under visible light. The improvement of the catalyst was clearly attributed to the co-incorporation of Cu and the ica ligand in the MOF, which reduces the band gap, in agreement with DFT calculations. Reproducibility and recyclability tests proved that Cu-ZIF-9-ica can be used for at least 3 cycles without a significant loss of efficiency, making it a promising material for the study and application of wastewater treatment.
KW - Metal-Organic Framework (MOF)
KW - Heterogeneous photo-Fenton
KW - ZIF-9
KW - Methylene Blue
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630797
DO - https://doi.org/10.1039/d4na00954a
SN - 2516-0230
VL - 7
IS - 8
SP - 2255
EP - 2265
PB - Royal Society of Chemistry
AN - OPUS4-63079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Page, T.M.
A1 - Nie, C.
A1 - Neander, L.
A1 - Povolotsky, T.L.
A1 - Sahoo, A.K.
A1 - Nickl, Philip
A1 - Adler, J.M.
A1 - Bawadkji, O.
A1 - Radnik, Jörg
A1 - Achazi, K.
A1 - Ludwig, K.
A1 - Lauster, D.
A1 - Netz, R.R.
A1 - Trimpert, J.
A1 - Kaufer, B.
A1 - Haag, R.
A1 - Donskyi, Ievgen
T1 - Functionalized Fullerene for Inhibition of SARS-CoV-2 Variants
N2 - As virus outbreaks continue to pose a challenge, a nonspecific viral inhibitor can provide significant benefits, especially against respiratory viruses. Polyglycerol sulfates recently emerge as promising agents that mediate interactions between cells and viruses through electrostatics, leading to virus inhibition.
Similarly, hydrophobic C60 fullerene can prevent virus infection via interactions with hydrophobic cavities of surface proteins. Here, two strategies are combined to inhibit infection of SARS-CoV-2 variants in vitro. Effective inhibitory concentrations in the millimolar range highlight the significance of bare fullerene’s hydrophobic moiety and electrostatic interactions of polysulfates with surface proteins of SARS-CoV-2. Furthermore, microscale thermophoresis measurements support that fullerene linear polyglycerol sulfates interact with the SARS-CoV-2 virus via its spike protein, and highlight importance of electrostatic interactions within it. All-atom molecular dynamics simulations reveal that the fullerene binding site is situated close to the receptor binding domain, within 4 nm of polyglycerol sulfate binding sites, feasibly allowing both portions of the material to interact simultaneously.
KW - Covalent functionalization
KW - Fullerene
KW - SARS-CoV 2
KW - Sulfated materials
KW - Virus inhibition
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568672
DO - https://doi.org/10.1002/smll.202206154
SN - 1613-6810
SP - 1
EP - 8
PB - Wiley VCH
AN - OPUS4-56867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bawadkji, O.
A1 - Cherri, M.
A1 - Schäfer, A.
A1 - Herziger, S.
A1 - Nickl, Philip
A1 - Achazi, K.
A1 - Donskyi, Ievgen
A1 - Adeli, M.
A1 - Haag, R.
T1 - One-pot covalent functionalization of 2D black phosphorus by anionic ring opening polymerization
N2 - In this work, a one-pot approach for the covalent functionalization of few-layer black phosphorus (BP) by anionic ring opening polymerization of glycidol to obtain multifunctional BP-polyglycerol (BP-PG) with high amphiphilicity for near-infrared-responsive drug delivery and biocompatibility is reported. Straightforward synthesis in combination with exceptional biological and physicochemical properties designates functionalized BP-PG as a promising candidate for a broad range of biomedical applications.
KW - 2D nanomaterial
KW - Amphiphilicity
KW - Black phosphorus
KW - Hyperbranched
KW - Polyglycerol
KW - Water dispersibility
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568833
DO - https://doi.org/10.1002/admi.202201245
SN - 2196-7350
VL - 9
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56883
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - 1,3-Dimethyl-imidazolium dimethyl phosphate ([MMIM]+[DMP]−) analyzed by XPS and HAXPES
N2 - The ionic liquid 1,3-dimethyl-imidazolium-dimethylphosphate ([MMIM]+[DMP]−) was analyzed using (hard) x-ray photoelectron spectroscopy.
Here, XPS and HAXPES spectra are shown in comparison. For the acquisition of the XPS spectra, monochromatic Al Kα radiation at 1486.6 eV was used, while for the acquisition of the HAXPES spectra, monochromatic Cr Kα radiation at 5414.8 eV was applied. Here, survey scans and high-resolution spectra of P 2p, P 2s, C 1s, O 1s, and N 1s for both methods and P 1s, P KL2,3L2,3, and P KL1L2,3 for HAXPES are shown.
KW - C7H15N2O4P
KW - [MMIM]+[DMP]−
KW - Lonic liquid
KW - Hard x-ray photoelectron spectroscopy
KW - HAXPES
KW - XPS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571604
DO - https://doi.org/10.1116/6.0002297
VL - 30
IS - 1
SP - 1
EP - 20
PB - AIP Publishing
AN - OPUS4-57160
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Z.
A1 - Perez, J. P. H.
A1 - Smales, Glen Jacob
A1 - Blukis, R.
A1 - Pauw, Brian Richard
A1 - Stammeier, J. A.
A1 - Radnik, Jörg
A1 - Smith, A. J.
A1 - Benning, L. G.
T1 - Impact of organic phosphates on the structure and composition of short-range ordered iron nanophases
N2 - Organic phosphates (OP) are important nutrient components for living cells in natural environments, where they readily interact with ubiquitous iron phases such as hydrous ferric oxide, ferrihydrite (FHY). FHY partakes in many key bio(geo)chemical reactions including iron-mediated carbon storage in soils, or iron-storage in living organisms. However, it is still unknown how OP affects the formation, structure and properties of FHY. Here, we document how β-glycerophosphate (GP), a model OP ligand, affects the structure and properties of GP–FHY nanoparticles synthesized by coprecipitation at variable nominal molar P/Fe ratios (0.01 to 0.5). All GP–FHY precipitates were characterized by a maximum solid P/Fe ratio of 0.22, irrespective of the nominal P/Fe ratio. With increasing nominal P/Fe ratio, the specific surface area of the GP–FHY precipitates decreased sharply from 290 to 3 m2 g−1, accompanied by the collapse of their pore structure. The Fe–P local bonding environment gradually transitioned from a bidentate binuclear geometry at low P/Fe ratios to monodentate mononuclear geometry at high P/Fe ratios. This transition was accompanied by a decrease in coordination number of edge-sharing Fe polyhedra, and the loss of the corner-sharing Fe polyhedra. We show that Fe(III) polymerization is impeded by GP, and that the GP–FHY structure is highly dependent on the P/Fe ratio. We discuss the role that natural OP-bearing Fe(III) nanophases have in biogeochemical reactions between Fe–P and C species in aquatic systems.
KW - Organic phosphates
KW - Iron nanophases
KW - Scattering
KW - Diffraction
KW - Nanomaterials
KW - Coprecipitation
KW - Carbon storage
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599399
DO - https://doi.org/10.1039/d3na01045g
SN - 2516-0230
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-59939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bennet, Francesca
A1 - Opitz, R.
A1 - Ghoreishi, N.
A1 - Plate, K.
A1 - Barnes, J.-P.
A1 - Bellew, A.
A1 - Bellu, A.
A1 - Ceccone, G.
A1 - de Vito, E.
A1 - Delcorte, A.
A1 - Franquet, A.
A1 - Fumageli, F.
A1 - Gilliland, D.
A1 - Jungnickel, H.
A1 - Lee, T.G.
A1 - Poleunis, C.
A1 - Rading, D.
A1 - Shon, H.K.
A1 - Spampinato, V.
A1 - Son, J.G.
A1 - Wang, F.
A1 - Wang, Y.-C. A.
A1 - Zhao, Y.
A1 - Roloff, A.
A1 - Tentschert, J.
A1 - Radnik, Jörg
T1 - VAMAS TWA2 interlaboratory comparison: Surface analysis of TiO2 nanoparticles using ToF-SIMS
N2 - Due to the extremely high specific surface area of nanoparticles and corresponding potential for adsorption, the results of surface analysis can be highly dependent on the history of the particles, particularly regarding sample preparation and storage. The sample preparation method has, therefore, the potential to have a significant influence on the results. This report describes an interlaboratory comparison (ILC) with the aim of assessing which sample preparation methods for ToF-SIMS analysis of nanoparticles provided the most intra- and interlaboratory consistency and the least amount of sample contamination. The BAM reference material BAM-P110 (TiO2 nanoparticles with a mean Feret diameter of 19 nm) was used as a sample representing typical nanoparticles. A total of 11 participants returned ToF-SIMS data,in positive and (optionally) negative polarity, using sample preparation methods of “stick-and-go” as well as optionally “drop-dry” and “spin-coat.” The results showed that the largest sources of variation within the entire data set were caused by adventitious hydrocarbon contamination or insufficient sample coverage, with the spin-coating protocol applied in this ILC showing a tendency toward insufficient sample coverage; the sample preparation method or the participant had a lesser influence on results.
KW - Secondary Ion Mass Spectrometry
KW - VMAAS
KW - Titania
KW - Interlaboratory comparison
KW - Reproducibility
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582290
DO - https://doi.org/10.1116/6.0002814
SN - 0734-2101
VL - 41
IS - 5
SP - 053210-1
EP - 053210-13
PB - AIP (American Institute of Physics)
AN - OPUS4-58229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hirahara, Kenta
A1 - Bonse, Jörn
A1 - Krüger, Jörg
A1 - Weise, Matthias
A1 - Ermilova, Elena
A1 - Schusterbauer, Robert
A1 - Unterreiner, Andreas-Neil
A1 - Hertwig, Andreas
T1 - A multi-method study of femtosecond laser modification and ablation of amorphous hydrogenated carbon coatings
N2 - e present a study on femtosecond laser treatment of amorphous hydrogen-containing carbon coatings (a-C:H). The coatings were deposited on silicon wafers by a plasma-assisted chemical vapour deposition (PA-CVD), resulting in two different types of material with distinct properties (referred to as “absorbing” and “semi-transparent” coatings in the following).
The samples were laser-treated with single fs-laser pulses (800 nm center wavelength, 35 fs pulse duration) in the ablative regime. Through a multi-method approach using topometry, Raman spectroscopy, and spectroscopic imaging ellipsometry, we can identify zones and thresholds of diferent fuence dependent efects and have access to the local dielectric function.
The two coating materials react signifcantly diferent upon laser treatment. We determined the (non-ablative) modifcation threshold fuence for the absorbing coating as 3.6 × 10−2 Jcm−2 and its ablation threshold as 0.22 Jcm−2. The semi-transparent coating does not show such a low-fuence modifcation but exhibits a characteristic interference-based intra-flm ablation mechanism with two distinguishable ablation thresholds at 0.25 and 0.28 Jcm−2, respectively. The combination of tailored layer materials and correlative imaging spectroscopic methods delivers new insights into the behaviour of materials when treated with ultrashort-pulse laser radiation
KW - Amorphous Hydrogenated Carbon Coatings
KW - Correlative Imaging Measurement Techniques
KW - Hybrid Metrology
KW - Imaging Spectroscopy
KW - Spectroscopic Ellipsometry
KW - Ultra-short Pulse Laser Materials Processing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617829
DO - https://doi.org/10.1007/s00339-024-07980-z
VL - 130
IS - 12
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-61782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Junge, Florian
A1 - Wittwer, Philipp
A1 - Sommerfeld, Thomas
A1 - Gehrenkemper, Lennart
A1 - Zoister, Christian
A1 - Nickl, Philip
A1 - Koch, Matthias
A1 - Meermann, Björn
A1 - Haag, Rainer
T1 - Adsorber Charge Dominates over Hydrophobic or Fluorophilic Functionalization in Influencing Adsorption of PFCA onto Polystyrene Resins
N2 - A systematic series of industrial-relevant polystyrene-based anion exchange resins that are functionalized with hydro- or fluorocarbon chains are compared regarding their adsorption behavior toward perfluorocarboxylic acids (PFCA) in respect to their charge, chain length, and type of chain. The results clearly show the dominance of electrostatic interactions in the adsorption process as uncharged adsorber materials showed no adsorption at all. In contrast, the charged adsorber materials showed in general a PFCA removal of 80% to 30% over the experiment depending on effluent fraction.
Unexpectedly, for perfluorobutanoic acid (PFBA) the highest removal rate is found with consistently >90%. Despite observing significant benefits in the adsorption of PFCA for fluoroalkylated adsorbers in comparison to their non-fluorinated counterparts, this effect of fluoroalkylation is comparatively small and can not be clearly attributed to fluorophilic interactions between the fluoroalkyl chains. These findings help clarifying that the introduction of fluorocarbon moieties in adsorber materials is not necessary in order to remove fluorocarbon molecules from the environment.
KW - PFAS
KW - Remediation
KW - Adsorption
KW - Fluorophilic interactions
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601883
DO - https://doi.org/10.1002/admi.202400199
SN - 2196-7350
SP - 1
EP - 10
PB - John Wiley & Sons
CY - Hoboken, New Jersey, USA
AN - OPUS4-60188
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nguyen, H. G.
A1 - Toman, B.
A1 - van Zee, R.
A1 - Prinz, Carsten
A1 - Thommes, M.
A1 - Ahmad, R.
A1 - Kiska, D.
A1 - Salinger, J.
A1 - Walton, I.
A1 - Walton, K.
A1 - Broom, D.
A1 - Benham, M.
A1 - Ansari, H.
A1 - Pini, R.
A1 - Petit, C.
A1 - Adolphs, J.
A1 - Schreiber, A.
A1 - Shigeoka, T.
A1 - Konishi, Y.
A1 - Nakai, K.
A1 - Henninger, M.
A1 - Petrzik, T.
A1 - Kececi, C.
A1 - Martis, V.
A1 - Paschke, T.
A1 - Mangano, E.
A1 - Brandani, S.
T1 - Reference isotherms for water vapor sorption on nanoporous carbon: results of an interlaboratory study
N2 - This paper reports the results of an international interlaboratory study sponsored by the Versailles Project on Advanced Materials and Standards (VAMAS) and led by the National Institute of Standards and Technology (NIST) on the measurement of water vapor sorption isotherms at 25 °C on a pelletized nanoporous carbon (BAM-P109, a certified reference material). Thirteen laboratories participated in the study and contributed nine pure water vapor isotherms and four relative humidity isotherms, using nitrogen as the carrier gas. From these data, reference isotherms, along with the 95% uncertainty interval (Uk=2), were determined and are reported in a tabular format.
KW - BAM-P109
KW - Interlaboratory study
KW - Nanoporous carbon
KW - Reference isotherm
KW - VAMAS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576560
DO - https://doi.org/10.1007/s10450-023-00383-1
SN - 0929-5607
SP - 1
EP - 12
PB - Springer
CY - Heidelberg
AN - OPUS4-57656
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
T1 - Validation of a low blow specimen technique for R-curve determination using a drop tower
N2 - Fracture mechanics based component design requires appropriate fracture mechanics toughness data with respect to both, loading rate as well as test temperature. Taking high-rate loading into account such as with accidental scenarios, different standards such as ASTM E 1820 or BS 7448-3 provide some information on dynamic fracture mechanics testing. Nevertheless, the designations differ so that a validation of the own material specific test method used for dynamic R-curve determination is mandatory. In order to address this for ductile cast iron materials an experimental method for the reliable determination of dynamic J-integral crack resistance curves at -40 °C following the multiple specimen approach has been established and validated. The experimental concept offers some additional valuable features. Single values of dynamic crack initiation toughness can be determined using a single specimen technique based on crack sensors. Furthermore, an experimentally independent method is provided according to which CTOD δ5 R-curves can be established. The focus of the present paper is on the validation of the experimental low blow technique using a drop tower test system.
A drop tower test system was developed and set up to perform low blow tests at temperatures down to -40 °C. The system allows for a variation of the impact mass and height and was optimized for testing of ductile cast iron at stress intensity rates from approximately 5∙10⁴ to 3∙10⁵ MPa√ms⁻¹. This range of loading rate is characteristic for instance with crash scenarios of heavy sectioned DCI casks for radioactive materials. In order to address characteristic challenges of impact tests (test duration of microseconds up to milliseconds, inertial effects, signal oscillations), an appropriate full bridge strain gage method for the measurement of force directly on the specimen as well as a non-contact measurement of load line displacement using an optical extensometer have been developed and validated.
The low blow test requires either to prevent bouncing strikes of the hammer by using the stop block technique or to catch the hammer after its first strike. Both options are not part of the experimental concept and setup which have been realized here. The paper describes investigations which have been performed in order to make sure that bouncing strikes of the hammer do not cause additional crack extension in the specimen. This is necessary to ensure a unique relation between the work done and the achieved crack extension. The investigations covered the analysis of limit loads of the specimen with respect to the measured force. The measured stiffness of the specimen was assessed and signals of crack sensors were analyzed. Furthermore, an analysis of the mechanical behavior of the loading system and the specimen by optical observation was performed. Corresponding results are discussed in the paper. It had finally been proven that additional crack extension in the specimen due to bouncing strikes of the hammer is not to be expected under the given conditions of test setup, material and loading. It can be seen as a major experimental advantage that the striker does not have to be catched after the low blow test.
T2 - XXIV Italian Group of Fracture Conference
CY - Urbino, Italy
DA - 01.03.2017
KW - Dynamic fracture mechanics
KW - R-curve
KW - Low blow
KW - Ductile cast iron
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-437686
DO - https://doi.org/10.1016/j.prostr.2017.04.005
SN - 2452-3216
VL - 3
SP - 25
EP - 32
AN - OPUS4-43768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ha, Q. L. M.
A1 - Armbruster, U.
A1 - Atia, Hanan
A1 - Lund, H.
A1 - Agostini, G.
A1 - Radnik, Jörg
A1 - Vuong, H. T.
A1 - Martin, A.
T1 - Development of active and stable low nickel content catalysts for dry reforming of methane
N2 - Methane dry reforming (DRM) was investigated over highly active Ni catalysts with low metal content (2.5wt%) supported on Mg-Al mixed oxide. The aim was to minimize carbon Deposition and metal sites agglomeration on the working catalyst which are known to cause catalyst deactivation.
The solids were characterized using N2 adsorption, X-ray diffraction, temperature-programmed reduction, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The results showed that MgO-Al2O3 solid solution phases are obtained when calcining Mg-Al hydrotalcite precursor in the temperature range of 550–800 °C. Such phases contribute to the high activity of catalysts with low Ni content even at low temperature (500 °C). Modifying the catalyst preparation with citric acid significantly slows the coking rate and reduces the size of large octahedrally coordinated NiO-like domains, which may easily agglomerate on the surface during DRM. The most effective Ni catalyst shows a stable DRM course over 60 h at high weight hourly space velocity with very low coke deposition. This is a promising result for considering such catalyst systems for further development of an industrial DRM technology.
KW - Dry reforming of methane
KW - Carbon dioxide
KW - Ni
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402904
DO - https://doi.org/10.3390/catal7050157
SN - 2073-4344
VL - 7
IS - 5
SP - 157, 1
EP - 157, 17
PB - MDPI
AN - OPUS4-40290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abbas, F.
A1 - Donskyi, Ievgen
A1 - Gholami, M.
A1 - Ziem, B.
A1 - Lippitz, Andreas
A1 - Unger, Wolfgang
A1 - Böttcher, C.
A1 - Rabe, J.
A1 - Haag, R.
A1 - Adeli, M.
T1 - Controlled covalent functionalization of thermally reduced graphene oxide to generate defined bifunctional 2D nanomaterials
N2 - A controlled, reproducible, gram-scale method is reported for the covalent functionalization of graphene Sheets by a one-pot nitrene [2+1] cycloaddition reaction under mild conditions. The reaction between commercially available 2,4,6-trichloro-1,3,5-triazine and sodium azide with thermally reduced graphene oxide (TRGO) results in defined dichlorotriazine-functionalized sheets. The different reactivities of the chlorine substituents on the functionalized graphene allow stepwise post-modification by manipulating the temperature.
This new method provides unique access to defined bifunctional 2D nanomaterials, as exemplified by chiral surfaces and multifunctional hybrid architectures.
KW - Graphene oxide
KW - Bifunctional 2D nanomaterials
KW - XPS
KW - NEXAFS
KW - AFM
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394789
DO - https://doi.org/10.1002/ange.201612422
SN - 1433-7851
VL - 56
IS - 10
SP - 2675
EP - 2679
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-39478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seeburg, Dominik
A1 - Liu, Dongjing
A1 - Radnik, Jörg
A1 - Atia, Hanan
A1 - Pohl, Marga-Martina
A1 - Schneider, Matthias
A1 - Martin, Andreas
A1 - Wohlrab, Sebastian
T1 - Structural changes of highly active Pd/MeOx (Me = Fe, Co, Ni) during catalytic methane combustion
N2 - Fe2O3, Co3O4 and NiO nanoparticles were prepared via a citrate method and further functionalized with Pd by impregnation. The pure oxides as well as Pd/Fe2O3, Pd/Co3O4, and Pd/NiO (1, 5 and 10 wt % Pd) were employed for catalytic methane combustion under methane lean (1 vol %)/oxygen rich (18 vol %, balanced with nitrogen) conditions. Already, the pure metal oxides showed a high catalytic activity leading to complete conversion temperature of T100 ≤ 500 °C. H2-TPR (Temperature-programmed reduction) experiments revealed that Pd-functionalized metal oxides exhibited enhanced redox activity compared to the pure oxides leading to improved catalytic combustion activity at lower temperatures. At a loading of 1 wt % Pd, 1Pd/Co3O4 (T100 = 360 °C) outperforms 1Pd/Fe2O3 (T100 = 410 °C) as well as 1Pd/NiO (T100 = 380 °C). At a loading of 10 wt % Pd, T100 could only be slightly reduced in all cases. 1Pd/Co3O4 and 1Pd/NiO show reasonable stability over 70 h on stream at T100. XPS (X-ray photoelectron spectroscopy) and STEM (Scanning transmission electron microscopy) investigations revealed strong interactions between Pd and NiO as well as Co3O4, respectively, leading to dynamic transformations and reoxidation of Pd due to solid state reactions, which leads to the high long-term stability.
KW - Methane total oxidation
KW - Methane removal
KW - Carbon dioxide
KW - X-ray photoelectron spectroscopy
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-439412
DO - https://doi.org/10.3390/catal8020042
SN - 2073-4344
VL - 8
IS - 2
SP - Article 42, 1
EP - 13
PB - MDPI
AN - OPUS4-43941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Unger, Wolfgang
A1 - Beiranvand, Z.
A1 - Kakanejadifard, A.
A1 - Donskyi, Ievgen
A1 - Faghani, A.
A1 - Tu, Z.
A1 - Lippitz, Andreas
A1 - Sasanpour, P.
A1 - Maschietto, F.
A1 - Paulus, B.
A1 - Haag, R.
A1 - Adeli, M.
T1 - Functionalization of fullerene at room temperature: toward new carbon vectors with improved physicochemical properties
N2 - In this work, fullerene has been functionalized with cyanuric Chloride at room temperature by a nitrene mediated [2 + 1] cycloaddition reaction. The adduct after functionalization is inherently in the form of azafulleroid and shows broad UV absorption in the wavelength range of 200–800 nm, as well as photothermal conversion and fluorescence with a high quantum yield.
KW - Functionalization of fullerenes
KW - XPS
KW - NEXAFS
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-387076
DO - https://doi.org/10.1039/c6ra23419d
SN - 2046-2069
VL - 6
IS - 114
SP - 112771
EP - 112775
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-38707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Broicher, Cornelia
A1 - Zeng, F.
A1 - Pfänder, N.
A1 - Frisch, M.
A1 - Bisswanger, T.
A1 - Radnik, Jörg
A1 - Stockmann, Jörg M.
A1 - Palkovits, S.
A1 - Beine, A. K.
A1 - Palkovits, R.
T1 - Iron and Manganese Containing Multi-Walled Carbon Nanotubes as Electrocatalysts for the Oxygen Evolution Reaction - Unravelling Influences on Activity and Stability
N2 - Hydrogen economy is a central aspect of future energy supply, as hydrogen can be used as energy storage and fuel. In order tomake water electrolysis efficient, the limiting oxygen evolution reaction (OER) needs to be optimized. Therefore, C-based composite materials containing earth-abundant Fe and Mn were synthesized, characterized and tested in the OER. For pyrolysis temperatures above 700°C N-rich multi-walled carbon nanotubes (MWCNT) are obtained. Inside the tubes Fe3C particles are formed, Fe and Mn oxides are incorporated in the carbon matrix and metal spinel nanoparticles cover the outer surface. The best catalyst prepared at 800°C achieves a low overpotential of 389 mV (at 10 mA/cm2) and high stability (22.6 h). From electrochemical measurements and characterization it can be concluded that the high activity is mainly provided by MWCNT, Fe3C and the metal oxides in the conductive carbon matrix. The metal spinel nanoparticles in
contrast protect the MWCNT from oxidation and thereby contribute to the high stability.
KW - Oxygen Evolution Reaction
KW - Carbon Nanotubes
KW - Stability
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513955
DO - https://doi.org/10.1002/cctc.202000944
VL - 12
IS - 21
SP - 1
EP - 8
PB - Wiley Online Libary
AN - OPUS4-51395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stockmann, Jörg M.
A1 - Radnik, Jörg
A1 - Bütefisch, S.
A1 - Busch, I.
A1 - Weimann, T.
A1 - Passiu, C.
A1 - Rossi, A.
A1 - Unger, Wolfgang
T1 - A new test specimen for the determination of the field of view of small-area X-ray photoelectron spectrometers
N2 - Small-area/spot photoelectron spectroscopy (SAXPS) is a powerful tool for the investigation of small surface features like microstructures of electronic devices, sensors or other functional surfaces, and so forth. For evaluating the quality of such microstructures, it is often crucial to know whether a small signal in a spectrum is an unwanted contamination of the field of view (FoV), defined by the instrument settings, or it originated from outside. To address this issue, the d80/20 parameter of a line scan across a chemical edge is often used. However, the typical d80/20 parameter does not give information on contributions from the long tails of the X-ray beam intensity distribution or the electron-optical system as defined by apertures. In the VAMAS TWA2 A22 project “Applying planar, patterned, multi-metallic samples to assess the impact of analysis area in surface-chemical analysis,” new test specimen was developed and tested. The here presented testing material consists of a silicon wafer substrate with an Au-film and embedded Cr circular and square spots with decreasing dimensions from 200 μm down to 5 μm. The spot sizes are traceable to the length unit due to size measurements with a metrological SEM. For the evaluation of the FoV, we determined the Au4f intensities measured with the center of the FoV aligned with the center of the spot and normalized to the Au4f intensity determined on the Au-film. With this test specimen, it was possible to characterize, as an example, the FoV of a Kratos AXIS Ultra DLD XPS instrument.
T2 - ECASIA 2019
CY - Dresden, Germany
DA - 15.09.2019
KW - Field of view
KW - Reference material
KW - Selected area XPS
KW - Small-area XPS
KW - Small-spot XPS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509902
DO - https://doi.org/10.1002/sia.6831
SN - 1096-9918
VL - 52
IS - 12
SP - 890
EP - 894
PB - John Wiley & Sons Ltd
AN - OPUS4-50990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Broichert, C.
A1 - Klingenhof, M.
A1 - Frisch, M.
A1 - Dresp, S.
A1 - Kubo, N.M.
A1 - Artz, J.
A1 - Radnik, Jörg
A1 - Palkovits, S.
A1 - Beine, A.K.
A1 - Strasser, P.
A1 - Palkovits, R.
T1 - Particle size-controlled synthesis of highperformance MnCo-based materials for alkaline OER at fluctuating potentials
N2 - For the large-scale generation of hydrogen via water electrolysis the design of long term stable and active catalysts for the oxygen evolution reaction (OER) remains a key challenge. Most catalysts suffer from severe structural corrosion that becomes even more pronounced at fluctuating potentials. Herein, MnCo based cubic particles were prepared via a hydrothermal approach, in which the edge length of the micron-sized particles can be controlled by changing the pH value of the precursor solution. The cubes are composed of varying amounts of MnCo2O4, CoCO3 and a mixed (Mn/Co)CO3 phase. Structure–activity relationships were deduced revealing a volcano-type behavior for the intrinsic OER activity and fraction of spinel oxide phase.
A low overpotential of 0.37 V at 10 mA cm−2 and a stability of more than 25 h was achieved in 1.0 M KOH using a rotating disc electrode (RDE) setup. The best performing catalyst material was successfully tested under dynamic process conditions for 9.5 h and shows a superior catalytic activity as anode for the Overall water splitting in an electrolyser setup in 1.0 M KOH at 333 K compared to a reference NiCo-spinel catalyst.
KW - Water electrolysis
KW - Oxygen evolution reaction
KW - Structure activity relationships
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536050
DO - https://doi.org/10.1039/d1cy00905b
SN - 2044-4753
VL - 11
IS - 12
SP - 7278
EP - 7286
PB - Royal Society of Chemistry
AN - OPUS4-53605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Falk, Florian
A1 - Menneken, M.
A1 - Stephan-Scherb, Christiane
T1 - Real-time observation of high- temperature gas corrosion in dry and wet SO2-containing atmosphere
N2 - Sulfur and water have a fundamental impact on the corrosion rate and potential failure of materials. It is therefore necessary to understand the mechanisms, rates, and potential means of transport, as well as the reactions of these elements with an alloy. This paper investigates the effect of water vapor in the initial stages of SO2 corrosion of an Fe-9Cr-0.5Mn model alloy at 650°C in situ under laboratory conditions using energy-dispersive x-ray diffraction analysis. Two separate experiments were run, one with a 99.5% Ar + 0.5% SO2 atmosphere and one with a 69.5% Ar + 0.5% SO2 + 30% H2O atmosphere. With a wet atmosphere, the alloy formed a scale with decreasing oxygen content towards the scale–alloy interface. Sulfides were identified above and below a (Fe, Cr)3O4 layer in the inner corrosion zone. In contrast to this, the overall scale growth was slower in a dry SO2 atmosphere.
KW - Early oxidation
KW - Early sulfidation
KW - Ferritic steels
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472844
UR - https://link.springer.com/article/10.1007/s11837-019-03335-9#enumeration
DO - https://doi.org/10.1007/s11837-019-03335-9
SN - 1047-4838
SN - 1543-1851
VL - 71
SP - 1
EP - 6
PB - Springer
CY - New York
AN - OPUS4-47284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - An, Biwen Annie
A1 - Shen, Y.
A1 - Voordouw, J.
A1 - Voordouw, G.
T1 - Halophilic methylotrophic methanogens may contribute to the high ammonium concentrations found in shale oil and shale gas reservoirs
N2 - Flow-back and produced waters from shale gas and shale oil fields contain high ammonium, which can be formed by methanogenic degradation of methylamines into methane and ammonium. Methylamines are added to fracturing fluid to prevent clay swelling or can originate from metabolism of the osmolyte triglycinebetaine (GB).
We analyzed field samples from a shale gas reservoir in the Duvernay Formation and from a shale oil reservoir in the Bakken formation in Canada to determine the origin of high ammonium. Fresh waters used to make fracturing fluid, early flow-back waters, and late flow back waters from the shale gas reservoir had increasing salinity of 0.01, 0.58, and 2.66 Meq of NaCl, respectively. Microbial community analyses reflected this fresh water to saline transition with halophilic taxa including Halomonas, Halanaerobium, and Methanohalophilus being increasingly present. Early and late flow-back waters had high ammonium concentrations of 32 and 15 mM, respectively.
Such high concentrations had also been found in the Bakken produced waters.
Enrichment cultures of Bakken produced waters in medium containing mono, di-, or trimethylamine, or triglycinebetaine (GB) converted these substrates into ammonium (up to 20 mM) and methane. The methylotrophic methanogen Methanohalophilus, which uses methylamines for its energy metabolism and uses GB as an osmolyte, was a dominant community member in these enrichments. Halanaerobium was also a dominant community member that metabolizes GB into trimethylamine, which is then metabolized further by Methanohalophilus. However, the micromolar concentrations of GB measured in shale reservoirs make them an unlikely source for the 1,000-fold higher ammonium concentrations in flow-back waters. This ammonium either originates directly from the reservoir or is formed from methylamines, which originate from the reservoir, or are added during the hydraulic fracturing process. These methylamines are then converted into ammonium and methane by halophilic methylotrophic methanogens, such as Methanohalophilus, present in flow-back waters.
KW - Methanogen
KW - Oil and gas industry
KW - Shale
KW - Halophile
KW - Corrosion
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474982
DO - https://doi.org/10.3389/fenrg.2019.00023
SN - 2296-598X
VL - 7
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-47498
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, Sascha
A1 - Jäger, L. A.
A1 - Karapanagiotis, Christos
A1 - Münzenberger, Sven
A1 - Kowarik, Stefan
T1 - Real-time dynamic strain sensing in optical fibers using artificial neural networks
N2 - We propose to use artificial neural networks (ANNs) for raw measurement data interpolation and signal shift computation and to demonstrate advantages for wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) and dynamic strain distribution measurement along optical fibers. The ANNs are trained with synthetic data to predict signal shifts from wavelength scans. Domain adaptation to measurement data is achieved, and standard correlation algorithms are outperformed. First and foremost, the ANN reduces the data analysis time by more than two orders of magnitude, making it possible for the first time to predict strain in real-time applications using the WS-COTDR approach. Further, strain noise and linearity of the sensor response are improved, resulting in more accurate measurements. ANNs also perform better for low signal-to-noise measurement data, for a reduced length of correlation input (i.e., extended distance range), and for coarser sampling settings (i.e., extended strain scanning range). The general applicability is demonstrated for distributed measurement of ground movement along a dark fiber in a telecom cable. The presented ANN-based techniques can be employed to improve the performance of a wide range of correlation or interpolation problems in fiber sensing data analysis and beyond.
KW - Distributed vibration sensing
KW - Distributed acoustic sensing
KW - Coherent optical time domain reflectometry
KW - Optical fiber sensor
KW - Artificial neural network
KW - Real time measurement
KW - Distributed strain sensing
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474832
UR - https://www.osapublishing.org/oe/abstract.cfm?uri=oe-27-5-7405
DO - https://doi.org/10.1364/OE.27.007405
SN - 1094-4087
VL - 27
IS - 5
SP - 7405
EP - 7425
PB - Optical Society of America
AN - OPUS4-47483
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Palkowski, Carsten
A1 - Zottl, A.
A1 - Malenkovic, I.
A1 - Simo, Anne
T1 - Fixing efficiency values by unfixing compressor speed: Dynamic test method for heat pumps
N2 - The growing market penetration of heat pumps indicates the need for a performance test method that better reflects the dynamic behavior of heat pumps. In this contribution, we developed and implemented a dynamic test method for the evaluation of the seasonal performance of heat pumps by means of laboratory testing. Current standards force the heat pump control inactive by fixing the compressor speed. In contrast, during dynamic testing, the compressor runs unfixed while the heat pump is subjected to a temperature profile. The profile consists of the different outdoor temperatures of a typical heating season based on the average European climate and also includes temperature changes to reflect the dynamic behavior of the heat pump. The seasonal performance can be directly obtained from the measured heating energy and electricity consumption making subsequent data interpolation and recalculation with correction factors obsolete. The method delivers results with high precision and high reproducibility and could be an appropriate method for a fair rating of heat pumps.
KW - Heat pump
KW - Dynamic test method
KW - Seasonal performance factor
KW - Variable frequency drive
KW - Energy label
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476944
DO - https://doi.org/10.3390/en12061045
SN - 1996-1073
VL - 12
IS - 6
SP - 1045, 1
EP - 16
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-47694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schumacher, David
A1 - Ou, D.
A1 - Ghafafian, Carineh
A1 - Zscherpel, Uwe
A1 - Trappe, Volker
T1 - Wind turbine rotor blade testing by dual-energy laminography
N2 - Modern wind turbine rotor blades consist of sandwich shell segments made from glass fiber reinforced polymers. During manufacturing, defects can arise which could lead to failure of the whole component under dynamic mechanical and thermal loads. Hence during operation defects can arise which, if detected, can be repaired locally and in-situ by applying repair patches instead of taking the whole rotor blade down and repair it remotely. This method is much more time and cost effective, since the shut-down time of the energy converter is limited to a minimum. These repair patches can, however, also lead to new defects if not applied optimally. Therefore, it is necessary to control the quality of the repair patches to ensure the best possible restoration of structural integrity of the component. As a rotor blade is an object with a large aspect ratio, X-ray laminography is predestined to provide 3D information of the objective volume. To enhance the amount of information gained from laminographic reconstruction, we use in this study a photon counting and energy discriminating X-ray detector and apply a material decomposition algorithm to the data. By inherently separating the incident spectra within the detection process into two distinct energy bins, the basis material decomposition can provide material resolved images. Choosing glass and epoxy resin as basis materials and numerically solving the inverse dual-energy equation system, the reconstructed laminographic datasets contain highly valuable information about the distribution of the basis materials within the structure. Furthermore, cross- artifacts arising from the limited angle of the projection data can be reduced by this method which allows to investigate structures that were hidden underneath the artefacts.
T2 - International Symposium on Digital Industrial Radiology and Computed Tomography – DIR2019
CY - Fürth, Germany
DA - 02.07.2019
KW - Laminography
KW - Wind energy
KW - Fiber reinforced polymer
KW - Photon counting detector
KW - Repair patch
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484380
UR - https://www.dir2019.com/portals/dir2019/bb/Tu.3.A.1.pdf
SN - 978-947971-06-0
SP - 1
EP - 13
AN - OPUS4-48438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Palkowski, Carsten
A1 - Schwarzenberg, S.
A1 - Simo, Anne
T1 - Seasonal cooling performance of air conditioners: The importance of independent test procedures used for MEPS and labels
N2 - Minimum energy performance standards and labels are commonly used tools to reduce the household energy use thus mitigating greenhouse gas emissions. However, the technical foundation for minimum energy performance standards and labels are test procedures for rating and testing of appliances. To de- termine the seasonal cooling performance of air conditioners, the current test standards require fixing of the compressor speed of the units to achieve steady-state conditions; this way of operation, how- ever, differs from real-life use. To make the seasonal cooling performance testing better reflect the real use conditions, this study proposes a compensation method which can be conducted independently from manufacturer data and still allows modulation of the tested units. Our results show that the tested units behave differently under part-load conditions, which results in a lower energy efficiency rating for some of the tested devices.
KW - Air conditioner
KW - Independent test method
KW - Real use behavior
KW - Seasonal energy efficiency ratio
KW - Minimum energy performance standards
KW - Energy label
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485813
DO - https://doi.org/10.1016/j.ijrefrig.2019.05.021
SN - 0140-7007
VL - 104
SP - 417
EP - 425
PB - Elsevier
AN - OPUS4-48581
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knieschewski, Arno
A1 - Stamminger, R.
A1 - Simo, Anne
T1 - Cost analysis of screening methods to find non-compliant models using the example of tumble dryers
N2 - The European energy label was established to reduce energy consumption in Europe. All classes and values on the energy label are stated by the supplier. The task of market surveillance is to ensure correct labels and to validate their values through compliance tests. However, this can only be done for a small fraction of all models on the market, since physical tests are expensive. Screening methods can be used to narrow down the number of critical products before compliance tests are done to decrease the costs of finding non-compliant models.
This study shows a mathematical approach to analyze the cost benefits of screening methods to find non-compliant models. Furthermore, the analysis presented has been applied to 18 screening methods for tumble dryers. The performance test for tumble dryers consists of seven test runs. All screening methods evaluated are composed of a reduced number of test runs. The most efficient screening method reduces the surveillance costs by 40 %.
KW - Screening method
KW - Market surveillance
KW - Tumble dryer
KW - Energy label
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486762
DO - https://doi.org/10.1007/s12053-019-09805-y
SN - 1570-646X
SN - 1570-6478
VL - 12
IS - 7
SP - 1707
EP - 1715
PB - Springer
CY - Dordrecht
AN - OPUS4-48676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Liehr, Sascha
A1 - Münzenberger, Sven
A1 - Krebber, Katerina
T1 - Wavelength-scanning distributed acoustic sensing for structural monitoring and seismic applications
N2 - We introduce wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) for dynamic vibration sensing along optical fibers. The method is based on spectral shift computation from Rayleigh backscatter spectra. Artificial neural networks (ANNs) are used for fast and high-resolution strain computation from raw measurement data. The applicability of the method is demonstrated for vibration monitoring of a reinforced concrete bridge. We demonstrate another application example for quasi-static and dynamic measurement of ground deformation and surface wave propagation along a dark fiber in a telecommunication cable.
T2 - 7th International Symposium on Sensor Science
CY - Napoli, Italy
DA - 09.05.2019
KW - Optical fiber sensor
KW - Distributed acoustic sensor (DAS)
KW - Optical time domain reflectometry
KW - Rayleigh scattering
KW - Artificial neural networks
KW - Structural health monitoring
KW - Seismic measurement
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487733
DO - https://doi.org/10.3390/proceedings2019015030
SN - 2504-3900
VL - 15
SP - Paper 30, 1
EP - 5
PB - MDPI
CY - Basel
AN - OPUS4-48773
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, Ronald
T1 - Effect of repair models on risk based optimal inspection strategies for support structures of offshore wind turbines
N2 - Owners or operators of offshore wind farms perform inspections to collect information on the condition of the wind turbine support structures and perform repairs if required. These activities are costly and should be optimized. Risk-based methods can be applied to identify inspection and repair strategies that ensure an optimal balance between the expected total service life cost of inspection and repair, and the achieved risk reduction. Such an optimization requires explicit modeling of repairs. In this paper, the impact of different repair models on the results of a risk-based optimization of inspection and repair strategies is quantified in a numerical example considering a jacket-type steel frame subject to high-cycle fatigue. The example showed that, in this specific application, there is no need for detailed modeling of the behavior of repaired welded connections.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019)
CY - Potsdam, Germany
DA - 27.08.2019
KW - Risk
KW - Reliability
KW - Inspection planning
KW - Offshore wind turbines
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488297
UR - https://www.smar2019.org/Portals/smar2019/bb/Th.2.A.4.pdf
SP - Paper Th.2.A.4, 1
EP - 8
AN - OPUS4-48829
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hüsken, Götz
A1 - Shamsuddoha, Md
A1 - Thiele, Marc
A1 - Baeßler, Matthias
A1 - Kühne, Hans-Carsten
T1 - Comparison of cracks formed in scaled grouted connection of offshore energy structures under static and cyclic loads
N2 - Global energy consumption will increase in the future necessitating both fossil fuels and renewable energy choices - especially wind energy. Such high energy demand requires installation of offshore energy structures, rigs, platforms and towers, which are susceptible to adverse environmental conditions along with maintenances. Due to their large size and remote locations, cylindrical grouted joints are often adopted between substructure and foundation in these offshore platforms and wind structures such as monopiles. However, these connections are composite structures with exterior sleeve, interior pile and infill mortar. Degradation and settlements were reported inside similar connections, which were installed in last three decades. Besides, grouting in the offshore sites were proven difficult to obtain ideal load bearing capacity. In-situ loading conditions were also found to be affecting the failure mechanism inside such connections. This study aims at characterizing the nature of cracks generated in these grouted connections under both static and cyclic loading. Scaled grouted joints were manufactured using a novel reusable mold, and connections were loaded to failure to visualize the main failure patterns. An assessment between failure under these two types of load is drawn along with comparison to previously available literature.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures
CY - Potsdam, Germany
DA - 27.08.2019
KW - Grouted connection
KW - Crack formation
KW - Crack pattern
KW - Static load
KW - Cyclic load
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487961
SP - Th.2.A.1-1
EP - Th.2.A.1-9
AN - OPUS4-48796
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kullolli, Borana
A1 - Cuéllar, Pablo
A1 - Baeßler, Matthias
A1 - Stutz, H. H.
T1 - Modelling and calibration for cyclic soil-structure interface behaviour
N2 - The structural performance of many geotechnical systems (e.g. axially-loaded pile foundations), depends on the shearing resistance at the soil interface, which may govern the load bearing capacity of the foundation. Experimental investigations have shown that this interaction is mainly localised within a narrow shear band next to the structure. Under cyclic loading, a contraction of the soil at the interface may arise (net volume loss), possibly leading to a stress relaxation and thus to a reduction of the load bearing capacity (the so-called friction fatigue). Based on the constitutive similarities between soil continua and interfaces, we propose here the adaption of a Generalized Plasticity model for sandy soils for the numerical analysis of interface problems. In this contribution, the results of an experimental campaign for the parameter calibration of the constitutive model are presented. The tests have been conducted with a ring shear device involving different normal stresses, roughness of the steel plates as well as cyclic loading. The new modelling approach shows promising results and has the additional practical advantage that the interface zone and the soil continuum can both be described with the same constitutive model in general boundary value problems.
T2 - Konferenz 7th International Symposium on Deformation Characteristics of Geomaterials
CY - Glasgow, Scotland
DA - 26.06.2019
KW - Soil-structure interaction
KW - Offshore foundations
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489096
DO - https://doi.org/10.1051/e3sconf/20199213007
VL - 92
SP - 13007
EP - 13013
PB - EDP Sciences
CY - Glasgow, Scotland
AN - OPUS4-48909
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Investigation of the salinization in marine and offshore environment - test methods and challenges
N2 - Salinization and contamination of metal surfaces by chloride-containing aerosols is of great importance with regard to corrosion phenomena in the maritime sector and in offshore applications. Especially Offshore Wind Turbines are exposed to extreme corrosive conditions due to high chloride concentrations in the atmosphere and the resulting high chloride deposition rates. It is of great importance to evaluate to what extent salinization of the surface influences the corrosion protection of coatings and pitting occurrence on stainless steels under atmospheric conditions to evaluate the durability of metallic building structures in offshore and marine environments. The evaluation of the scientific literature and regulatory guidelines has shown that there are still many open questions regarding the contamination of metal surfaces by chlorides. This contribution will discuss how salinization of metal surfaces is evaluated and monitored according to current standards and guidelines. Future challenges concerning test methods and the application of evaluated salinization values and deposition rates will be discussed.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures
CY - Potsdam, Germany
DA - 27.08.20019
KW - Maritime Atmosphäre
KW - Versalzung
KW - Maritime atmosphere
KW - Salinization
PY - 2019
SP - Th.2.A.5, 1
EP - 8
PB - SMAR 2019
AN - OPUS4-48905
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haustein, T.
A1 - Busweiler, Sabine
A1 - Haustein, V.
A1 - von Laar, C.
A1 - Plarre, Rüdiger
T1 - Laboratory breeding of Korynetes caeruleus (Coleoptera: Cleridae) for the biological of Anobium punctatum) (Coleoptera, Ptinidae)
N2 - Larvae and adults of Korynetes caeruleus (de Geer 1775) (Coleoptera: Cleridae) were collected from old churches and reared in the laboratory on Anobium punctatum (de Geer 1774) (Coleoptera: Ptinidae). Breeding success of K. caeruleus was low, but basic parameters of this species’ developmental cycle were identifi ed. At 21°C and 75% relative humidity and a fourmonth cold period at 4°C, the development of K. caeruleus from egg to adult appearance lasted 2 years. The pupal stage may be reached and completed after one and a half years. Feeding on larvae of A. punctatum by larvae of K. caeruleus was observed and consisted of a combination of sucking haemolymph and consuming body parts. The sickle-like mandibles of larvae of K. caeruleus penetrate the cuticle of prey larvae; this is followed by pumping and sucking body movements. Adult beetles of A. punctatum were not attacked by K. caeruleus larvae. Feeding behaviour of adult K. caeruleus was not investigated.
KW - Cultural heritage
KW - Coleoptera
KW - Korynetes caeruleus
KW - Cleridae
KW - Ptinidae
KW - Anobium punctatum
KW - Biological pest control
KW - Life history data
KW - Laboratory breeding
KW - Wood protection
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494999
DO - https://doi.org/10.14411/eje.2019.038
SN - 1802-8829
VL - 116
SP - 362
EP - 371
PB - České Budějovice
AN - OPUS4-49499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kindrachuk, Vitaliy
A1 - Fedelich, Bernard
A1 - Rehmer, Birgit
A1 - Peter, Frauke
T1 - Computational methods for lifetime prediction of metallic components under high-temperature fatigue
N2 - The issue of service life prediction of hot metallic components subjected to cyclic loadings is addressed. Two classes of lifetime models are considered, namely, the incremental lifetime rules and the parametric models governed by the fracture mechanics concept. Examples of application to an austenitic cast iron are presented. In addition, computational techniques to accelerate the time integration of the incremental models throughout the fatigue loading history are discussed. They efficiently solve problems where a stabilized response of a component is not observed, for example due to the plastic strain which is no longer completely reversed and accumulates throughout the fatigue history. The performance of such an accelerated Integration technique is demonstrated for a finite element simulation of a viscoplastic solid under repeating loading–unloading cycles.
KW - Fatigue
KW - Incremental lifetime models
KW - Finite element analysis
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481215
UR - https://www.mdpi.com/2075-4701/9/4/390
DO - https://doi.org/10.3390/met9040390
SN - 2075-4701
VL - 9
IS - 4
SP - 390, 1
EP - 24
PB - mdpi
CY - Basel, Switzerland
AN - OPUS4-48121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -