TY - JOUR A1 - Schmidt, C. A1 - Hensen, C. A1 - Wallmann, K. A1 - Liebetrau, V. A1 - Tatzel, Michael A1 - Schurr, S. L. A1 - Kutterolf, S. A1 - Haffert, L. A1 - Geilert, Sonja A1 - Hübscher, C. A1 - Lebas, E. A1 - Heuser, A. A1 - Schmidt, M. A1 - Strauss, H. A1 - Vogl, Jochen A1 - Hansteen, T. T1 - Origin of High Mg and SO4 Fluids in Sediments of the Terceira Rift, Azores‐Indications for Caminite Dissolution in a Waning Hydrothermal System N2 - During R/V Meteor cruise 141/1, pore fluids of near surface sediments were investigated to find indications for hydrothermal activity in the Terceira Rift (TR), a hyperslow spreading center in the Central North Atlantic Ocean. To date, submarine hydrothermal fluid venting in the TR has only been reported for the D. João de Castro seamount, which presently seems to be inactive. Pore fluids sampled close to a volcanic cone at 2,800‐m water depth show an anomalous composition with Mg, SO4, and total alkalinity concentrations significantly higher than seawater and a nearby reference core. The most straightforward way of interpreting these deviations is the dissolution of the hydrothermally formed mineral caminite (MgSO4 0.25 Mg (OH)2 0.2H2O). This interpretation is corroborated by a thorough investigation of fluid isotope systems (δ26Mg, δ30Si, δ34S, δ44/42Ca, and 87Sr/86Sr). Caminite is known from mineral assemblages with anhydrite and forms in hydrothermal recharge zones only under specific conditions such as high fluid temperatures and in altered oceanic crust, which are conditions generally met at the TR. We hypothesize that caminite was formed during hydrothermal activity and is now dissolving during the waning state of the hydrothermal system, so that caminite mineralization is shifted out of its stability zone. Ongoing fluid circulation through the basement is transporting the geochemical signal via slow advection toward the seafloor. KW - Isotope ratio KW - Delta value KW - Pore fluids KW - Magnesium KW - Hydrothermal fluid PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503430 DO - https://doi.org/10.1029/2019GC008525 VL - 20 IS - 12 SP - 6078 EP - 6094 PB - Wiley AN - OPUS4-50343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bachmann, H. J. A1 - Bucheli, T. D. A1 - Dieguez-Alonso, A. A1 - Fabbri, D. A1 - Knicker, H. A1 - Schmidt, H.-P. A1 - Ulbricht, A. A1 - Becker, Roland A1 - Buscaroli, A. A1 - Buerge, D. A1 - Cross, A. A1 - Dickinson, D. A1 - Enders, A. A1 - Esteves, V.I. A1 - Evangelou, M. W. H. A1 - Fellet, G. A1 - Friedrich, K. A1 - Gasco Guerrero, G. A1 - Glaser, B. A1 - Hanke, U. M. A1 - Hanley, K. A1 - Hilber, I. A1 - Kalderis, D. A1 - Leifeld, J. A1 - Masek, O. A1 - Mumme, J. A1 - Paneque Carmona, M. A1 - Calvelo Pereira, R. A1 - Rees, F. A1 - Rombola, A. G. A1 - de la Rosa, J. M. A1 - Sakrabani, R. A1 - Sohi, S. A1 - Soja, G. A1 - Valagussa, M. A1 - Verheijen, F. A1 - Zehetner, F. T1 - Towards the standardization of biochar analysis: the COST action TD1107 interlaboratory comparison N2 - Biochar produced by pyrolysis of organic residues is increasingly used for soil amendment and many other applications. However, analytical methods for its physical and chemical characterization are yet far from being specifically adapted, optimized, and standardized. Therefore, COST Action TD1107 conducted an interlaboratory comparison in which 22 laboratories from 12 countries analyzed three different types of biochar for 38 physical–chemical parameters (macro- and microelements, heavy metals, polycyclic aromatic hydrocarbons, pH, electrical conductivity, and specific surface area) with their preferential methods. The data were evaluated in detail using professional interlaboratory testing software. Whereas intralaboratory repeatability was generally good or at least acceptable, interlaboratory reproducibility was mostly not (20% < mean reproducibility standard deviation < 460%). This paper contributes to better comparability of biochar data published already and provides recommendations to improve and harmonize specific methods for biochar analysis in the future. KW - Biochar KW - Analysis KW - Standardization KW - Ring test KW - Interlaboratory comparison PY - 2016 DO - https://doi.org/10.1021/acs.jafc.5b05055 SN - 0021-8561 SN - 1520-5118 VL - 64 IS - 2 SP - 513 EP - 527 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-35289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jablonka, Kevin Maik A1 - Ai, Qianxiang A1 - Al-Feghali, Alexander A1 - Badhwar, Shruti A1 - Bocarsly, Joshua D. A1 - Bran, Andres M. A1 - Bringuier, Stefan A1 - Brinson, L. Catherine A1 - Choudhary, Kamal A1 - Circi, Defne A1 - Cox, Sam A1 - de Jong, Wibe A. A1 - Evans, Matthew L. A1 - Gastellu, Nicolas A1 - Genzling, Jerome A1 - Gil, María Victoria A1 - Gupta, Ankur K. A1 - Hong, Zhi A1 - Imran, Alishba A1 - Kruschwitz, Sabine A1 - Labarre, Anne A1 - Lála, Jakub A1 - Liu, Tao A1 - Ma, Steven A1 - Majumdar, Sauradeep A1 - Merz, Garrett W. A1 - Moitessier, Nicolas A1 - Moubarak, Elias A1 - Mouriño, Beatriz A1 - Pelkie, Brenden A1 - Pieler, Michael A1 - Ramos, Mayk Caldas A1 - Ranković, Bojana A1 - Rodriques, Samuel G. A1 - Sanders, Jacob N. A1 - Schwaller, Philippe A1 - Schwarting, Marcus A1 - Shi, Jiale A1 - Smit, Berend A1 - Smith, Ben E. A1 - Van Herck, Joren A1 - Völker, Christoph A1 - Ward, Logan A1 - Warren, Sean A1 - Weiser, Benjamin A1 - Zhang, Sylvester A1 - Zhang, Xiaoqi A1 - Zia, Ghezal Ahmad Jan A1 - Scourtas, Aristana A1 - Schmidt, K. J. A1 - Foster, Ian A1 - White, Andrew D. A1 - Blaiszik, Ben T1 - 14 examples of how LLMs can transform materials science and chemistry: a reflection on a large language model hackathon N2 - Large-language models (LLMs) such as GPT-4 caught the interest of many scientists. Recent studies suggested that these models could be useful in chemistry and materials science. To explore these possibilities, we organized a hackathon. This article chronicles the projects built as part of this hackathon. Participants employed LLMs for various applications, including predicting properties of molecules and materials, designing novel interfaces for tools, extracting knowledge from unstructured data, and developing new educational applications. The diverse topics and the fact that working prototypes could be generated in less than two days highlight that LLMs will profoundly impact the future of our fields. The rich collection of ideas and projects also indicates that the applications of LLMs are not limited to materials science and chemistry but offer potential benefits to a wide range of scientific disciplines. KW - Large Language model KW - Hackathon KW - Concrete KW - Prediction KW - Inverse Design KW - Orchestration PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589961 DO - https://doi.org/10.1039/d3dd00113j VL - 2 IS - 5 SP - 1233 EP - 1250 PB - Royal Society of Chemistry (RSC) AN - OPUS4-58996 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thomsen-Schmidt, P. A1 - Hasche, K. A1 - Ulm, G. A1 - Herrmann, K. A1 - Krumrey, M. A1 - Ade, G. A1 - Stümpel, J. A1 - Busch, I. A1 - Schädlich, S. A1 - Schindler, A. A1 - Frank, W. A1 - Hirsch, D. A1 - Procop, Mathias A1 - Beck, Uwe T1 - Realisation and metrological characterisation of thickness standards below 100 nm N2 - High-accuracy film thickness measurements in the range below 100 nm can be made by various complex methods like spectral ellipsometry (SE), scanning force microscopy (SFM), grazing incidence X-ray reflectometry (GIXR), or X-ray fluorescence analysis (XRF). The measurement results achieved with these methods are based on different interactions between the film and the probe. A key question in nanotechnology is how to achieve consistent results on a level of uncertainty below one nanometre with different techniques. Two different types of thickness standards are realised. Metal film standards for X-ray techniques in the thickness range 10 to 50 nm are calibrated by GIXR with monochromatised synchrotron radiation of 8048 eV. The results obtained at four different facilities show excellent agreement. SiO2 on Si standards for SE and SFM in the thickness range 6 to 1000 nm are calibrated by GIXR with monochromatised synchrotron radiation of 1841 eV and with a metrological SFM. Consistent results within the combined uncertainties are obtained with the two methods. Surfaces and interfaces of both types of standards are additionally investigated by transmission electron microscopy (TEM). PY - 2004 DO - https://doi.org/10.1007/s00339-003-2273-7 SN - 0947-8396 VL - 78 IS - 5 SP - 645 EP - 649 PB - Springer CY - Berlin AN - OPUS4-17195 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spallanzani, Roberta A1 - Koga, K. A1 - Cichy, S. A1 - Wiedenbeck, M. A1 - Schmidt, B. A1 - Oelze, Marcus A1 - Wilke, M. T1 - Lithium and boron difusivity and isotopic fractionation in hydrated rhyolitic melts N2 - Lithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. In this study, we determine the difusivity and isotopic fractionation of Li and B in hydrous silicate melts. Two glasses were synthesized with the same rhyolitic composition (4.2 wt% water), having diferent Li and B contents; these were studied in difusion-couple experiments that were performed using an internally heated pressure vessel, operated at 300 MPa in the temperature range 700–1250 °C for durations from 0 s to 24 h. From this we determined activation energies for Li and B difusion of 57±4 kJ/mol and 152±15 kJ/mol with pre-exponential factors of 1.53 × 10–7 m2/s and 3.80× 10–8 m2 /s, respectively. Lithium isotopic fractionation during difusion gave β values between 0.15 and 0.20, whereas B showed no clear isotopic fractionation. Our Li difusivities and isotopic fractionation results difer somewhat from earlier published values, but overall confrm that Li difusivity increases with water content. Our results on B difusion show that similarly to Li, B mobility increases in the presence of water. By applying the Eyring relation, we confrm that B difusivity is limited by viscous fow in silicate melts. Our results on Li and B difusion present a new tool for understanding degassing-related processes, ofering a potential geospeedometer to measure volcanic ascent rates. KW - Hydrated silicate melts KW - Stable isotopes KW - Diffusion KW - Isotopic fractionation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554496 DO - https://doi.org/10.1007/s00410-022-01937-2 VL - 177 IS - 8 SP - 1 EP - 17 PB - Springer AN - OPUS4-55449 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, M. A1 - Bettge, Dirk A1 - Hilgenberg, Kai A1 - Binder, M. A1 - Dollmeier, K. A1 - Dreyer, M. A1 - Klöden, B. A1 - Schlingmann, T. A1 - Schmidt, J. T1 - Reproducibility and Scattering in Additive Manufacturing: Results from a Round Robin on PBF-LB/M AlSi10Mg Alloy T1 - Reproduzierbarkeit und Streuung bei der additiven Fertigung: Ergebnisse eines Ringversuchs mit einer PBF-LB/M AlSi10Mg-Legierung N2 - The round robin test investigated the reliability users can expect for AlSi10Mg additive manufactured specimens by laser powder bed fusion through examining powder quality, process parameter, microstructure defects, strength and fatigue. Besides for one outlier, expected static material properties could be found. Optical microstructure inspection was beneficial to determine true porosity and porosity types to explain the occurring scatter in properties. Fractographic analyses reveal that the fatigue crack propagation starts at the rough as-built surface for all specimens. Statistical analysis of the scatter in fatigue using statistical derived safety factors concludes that at a stress of 36.87 MPa the fatigue limit of 107 cycles could be reached for all specimen with a survival probability of 99.999 %. N2 - Im Rahmen eines Ringversuchs wurde durch die Untersuchung der Pulverqualität, der Prozessparameter, der Gefügefehler, der Festigkeit und der Ermüdung die Zuverlässigkeit bestimmt, die Nutzer von AlSi10Mg-Proben erwarten können, die mit pulverbettbasiertes Schmelzen mittels Laser (engl. Laser Powder Bed Fusion) gefertigt worden sind. Abgesehen von einem Ausreißer wurden die erwarteten statischen Materialeigenschaften erreicht. Eine optische Gefügeprüfung diente dazu, die tatsächliche Porosität und Arten von Porosität zu ermitteln, um die bei den Eigenschaften auftretende Streuung zu erklären. Fraktographische Unterschungen zeigen eine bei allen Proben von der rauen Oberfläche im As-built-Zustand ausgehende Ermüdungsrissausbreitung. Aus der statistischen Analyse der Streuung bezüglich der Ermüdung unter Anwendung von statistischen abgeleiteten Sicherheitsfaktoren geht hervor, dass alle Proben die Dauerfestigkeit von 107 Zyklen bei einer Spannung von 36,87 MPa mit einer Überlebenswahrscheinlichkeit von 99,999 % erreichten. KW - Additive manufacturing KW - Reproducibility KW - Reliability PY - 2022 DO - https://doi.org/10.1515/pm-2022-1018 SN - 2195-8599 VL - 59 IS - 10 SP - 580 EP - 614 PB - De Gruyter AN - OPUS4-55935 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, R. A1 - Beck, Uwe A1 - Weigl, B. A1 - Gamer, Nadja A1 - Reiners, Georg A1 - Sommer, K. T1 - Topografische Charakterisierung von Oberflächen im steriltechnischen Anlagenbau PY - 2003 SN - 0009-286X SN - 1522-2640 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-2142 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, R. A1 - Beck, Uwe A1 - Weigl, B. A1 - Gamer, Nadja A1 - Reiners, Georg A1 - Sommer, K. T1 - Topographische Charakterisierung von Oberflächen im steriltechnischen Anlagenbau PY - 2003 SN - 0009-286X SN - 1522-2640 VL - 75 IS - 4 SP - 428 EP - 431 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-2557 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Debatin, F. A1 - Behrens, K. A1 - Weber, J. A1 - Baburin, I. A. A1 - Thomas, A. A1 - Schmidt, J. A1 - Senkovska, I. A1 - Kaskel, S. A1 - Kelling, A. A1 - Hedin, N. A1 - Bacsik, Z. A1 - Leoni, S. A1 - Seifert, G. A1 - Jäger, Christian A1 - Günter, C. A1 - Schilde, U. A1 - Friedrich, A. A1 - Holdt, H.-J. T1 - An isoreticular family of microporous metal-organic frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate: syntheses, structures and properties N2 - We report on a new series of isoreticular frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate (IFP-1–4, IFP=imidazolate framework Potsdam) that form one-dimensional, microporous hexagonal channels. Varying R in the 2-substitued linker (R=Me (IFP-1), Cl (IFP-2), Br (IFP-3), Et (IFP-4)) allowed the channel diameter (4.0–1.7 Å), the polarisability and functionality of the channel walls to be tuned. Frameworks IFP-2, IFP-3 and IFP-4 are isostructural to previously reported IFP-1. The structures of IFP-2 and IFP-3 were solved by X-ray crystallographic analyses. The structure of IFP-4 was determined by a combination of PXRD and structure modelling and was confirmed by IR spectroscopy and 1H MAS and 13C CP-MAS NMR spectroscopy. All IFPs showed high thermal stability (345–400°C); IFP-1 and IFP-4 were stable in boiling water for 7 d. A detailed porosity analysis was performed on the basis of adsorption measurements by using various gases. The potential of the materials to undergo specific interactions with CO2 was investigated by measuring the isosteric heats of adsorption. The capacity to adsorb CH4 (at 298 K), CO2 (at 298 K) and H2 (at 77 K) at high pressure were also investigated. In situ IR spectroscopy showed that CO2 is physisorbed on IFP-1–4 under dry conditions and that both CO2 and H2O are physisorbed on IFP-1 under moist conditions. KW - Adsorption KW - Metal-organic frameworks KW - Microporous materials KW - N,O ligands KW - Zinc PY - 2012 DO - https://doi.org/10.1002/chem.201200889 SN - 0947-6539 SN - 1521-3765 VL - 18 IS - 37 SP - 11630 EP - 11640 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaplan, F. A1 - Steinbock, O. A1 - Saloga, K. A1 - Ebell, Gino A1 - Schmidt, S. T1 - Überwachung der Brücke am Altstädter Bahnhof T1 - Monitoring of the bridge at the Altstadter Bahnhof in Brandenburg a. d. Havel N2 - Die B 1-Brücke am Altstädter Bahnhof war der wichtigste Verkehrsknotenpunkt in Brandenburg an der Havel. Im Dezember 2019 wurden die überführte Bundesstraße und die Straßenbahnlinie für den Verkehr gesperrt. Grund für die Sperrung war eine einsetzende Rissbildung in den Längsträgerstegen in Verbindung mit Hohlstellen, die letztlich auf gerissene Spanndrähte zurückgeführt werden. Um eine Sperrung der hoch frequentierten unterführten Verkehrswege zu verhindern, wurde ein umfangreiches Überwachungskonzept erforderlich. Wesentlicher Bestandteil dieses Konzepts war ein auf der Schallemissionsanalyse basierendes Monitoringsystem, mit dessen Hilfe Spanndrahtbrüche aufgezeichnet und lokalisiert werden konnten. Auf Grundlage der so gewonnenen Ergebnisse konnten Schwerpunkte für die Bauwerksprüfung abgeleitet werden. In diesem Bericht werden die gewonnenen Erkenntnisse zum messtechnisch erfassten Schadensfortschritt und den damit verbundenen visuell festgestellten Schäden beschrieben. Dabei werden die Besonderheit des verbauten konzentrierten Spannglieds (Spannblockverfahren nach TGL 173-33) und des Spannstahls in Bezug auf die Schadensbilder dargestellt. Die gewonnenen Erkenntnisse sollten bei der Beurteilung anderer Bauwerke mit vergleichbarer Bauart berücksichtigt werden. KW - Korrosion KW - Spannstahl KW - Spannungsrisskorrosion PY - 2022 DO - https://doi.org/10.1002/bate.202200008 SN - 0932-8351 VL - 99 IS - 3 SP - 222 EP - 230 PB - Ernst & Sohn AN - OPUS4-54485 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eichelbaum, M. A1 - Kneipp, Janina A1 - Schmidt, B.E. A1 - Panne, Ulrich A1 - Rademann, K. T1 - SERS and Multiphoton-Induced Luminescence of Gold Micro- and Nanostructures Fabricated by NIR Femtosecond-Laser Irradiation KW - Gold KW - Luminescence KW - Multiphoton fabrication KW - Sol-gel processes KW - Surface-enhanced Raman scattering PY - 2008 DO - https://doi.org/10.1002/cphc.200800417 SN - 1439-4235 SN - 1439-7641 VL - 9 IS - 15 SP - 2163 EP - 2167 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-18233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lüth, Peter A1 - Uhlig, S. A1 - Frost, K. A1 - Malow, Marcus A1 - Michael-Schulz, Heike A1 - Schmidt, Martin A1 - Zakel, Sabine T1 - CEQAT-DGHS interlaboratory tests for chemical safety: Validation of laboratory test methods by determining the measurement uncertainty and probability of incorrect classification including so-called “Shark profiles” N2 - Laboratory test results are of vital importance for correctly classifying and labelling chemicals as “hazardous” as defined in the UN Globally Harmonized System (GHS) / EC CLP Regulation or as “dangerous goods” as defined in the UN Recommendations on the Transport of Dangerous Goods. Interlaboratory tests play a decisive role in assessing the reliability of laboratory test results. Interlaboratory tests performed over the last 10 years have examined different laboratory test methods. After analysing the results of these interlaboratory tests, the following conclusions can be drawn: 1. There is a need for improvement and validation for all laboratory test methods examined. 2. To avoid any discrepancy concerning the classification and labelling of chemicals, the use of validated laboratory test methods should be state of the art, with the results accompanied by the measurement uncertainty and (if applicable) the probability of incorrect classification. This paper addresses the probability of correct/incorrect classification (for example, as dangerous goods) on the basis of the measurement deviation obtained from interlaboratory tests performed by the Centre for quality assurance for testing of dangerous goods and hazardous substances (CEQAT-DGHS) to validate laboratory test methods. This paper outlines typical results (e.g. so-called “Shark profiles” – the probability of incorrect classification as a function of the true value estimated from interlaboratory test data) as well as general conclusions and steps to be taken to guarantee that laboratory test results are fit for purpose and of high quality. T2 - 13th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE 2020) CY - Brunswick, Germany DA - 27.07.2020 KW - Dangerous goods KW - Hazardous substances KW - Interlaboratory test KW - Test method KW - Validation KW - Quality assurance KW - Measurement uncertainty KW - Incorrect classification KW - Shark profiles PY - 2021 DO - https://doi.org/10.1016/j.jlp.2021.104532 SN - 0950-4230/ VL - 72 SP - 104532 PB - Elsevier Ltd. AN - OPUS4-52751 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, K. A1 - Mezhov, Alexander A1 - Schmidt, Wolfram T1 - Effect of agitation during the early‑age hydration on thixotropy and morphology of cement paste N2 - The effect of agitation during the earlyage hydration on thixotropy and morphology of cement paste prepared with and without superplasticizers (SP) is investigated by applying penetration test, small amplitude oscillatory shear sweep test (SAOS), isothermal calorimetric test, scanning electron microscopy (SEM) and energy dispersive X-ray analyses (EDX). The results show that the agitation of cement paste during the induction period increases the heat flow rate and destroys existing structures of samples without changing the mineral composition of samples. Yet, if the agitation is applied during the acceleration period, the heat flow rate is significantly lowered and the morphology and mineral composition of samples undergo irreversible change, freshly formed syngenite is destroyed and no longer restored. The penetration force and the static yield stress grow linearly during the induction period and exponentially during the acceleration period. Agitation during the induction period destroys the structure, which causes the static yield stress and the penetration force values becoming nearly equal to zero. However, during the acceleration period, even after agitation the static yield stress and the penetration force exhibit high residual values, which indicates the impact of hydration to the structural build-up. KW - Hydration · Thixotropy KW - Agitation KW - Morphology KW - Structural build-up PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621189 DO - https://doi.org/10.1617/s11527-024-02504-w VL - 57 SP - 1 EP - 13 PB - Springer Nature Switzerland AG CY - Schweiz AN - OPUS4-62118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mezhov, Alexander A1 - Ben Shir, I. A1 - Schmidt, A. A1 - Kovler, K. A1 - Diesendruck, Ch. E. T1 - Retardation mechanism of cement hydration by a comb polyphosphate superplasticizer N2 - The retardation mechanism of cement hydration as imparted by the addition of polyphosphate comb superplasticizer to model cement containing C3S, C3A and calcium sulfate hemihydrate is studied using XRD, ss NMR and calorimetry. Our findings show the retardation effect caused by the direct addition of polyphosphate comb superplasticizer differs significantly to that of conventional polycarboxylate superplasticizers. Conversely to polycarboxylates, polyphosphates, at a low dosage, inhibits the silicate reaction without affecting the aluminate reaction and formation of ettringite. Yet, at high doses, both reactions are hampered, and the induction period extended, followed by accelerated aluminate and silicate reactions. KW - Superplasticizer KW - Polyphosphate KW - Retardation KW - Cement hydration PY - 2022 DO - https://doi.org/10.1016/j.conbuildmat.2022.128698 SN - 0950-0618 VL - 352 SP - 1 EP - 13 PB - Elsevier Ltd. AN - OPUS4-58246 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gladrow, K. A1 - Unkovskiy, A. A1 - Yassine, J. A1 - Gaertner, N. A1 - Topolniak, Ievgeniia A1 - Henning, N. A1 - Schmidt, F. T1 - The effect of nitrogen atmosphere during post-curing on cytotoxicity, polishability, flexural strength, and surface hardness of 3D-printed denture bases: an in vitro study N2 - 3D printing is increasingly utilized in dentistry. Compared to traditional manufacturing methods, 3D printing provides advantages such as faster production times and the ability to create complex structures. Although biocompatible materials are available, many are only suitable for temporary applications. This study examines the impact of nitrogen-aided post-processing on the mechanical properties and cytotoxicity of 3D-printed denture bases, with the hypothesis that this post-processing will enhance material properties and decrease cytotoxicity. Specimens were fabricated from V-print dentbase (Voco GmbH, Cuxhaven, Germany) and post-processed either in nitrogen or air. The specimens were categorized into aged and non-aged groups. For comparison, specimens made from milled material were utilized. Vickers hardness, flexural strength, polishability, cytotoxicity, and degree of conversion were then assessed for all groups. The data were analyzed using a one-way ANOVA and Tukey HSD test for multiple comparisons, with a significance threshold of p < 0.05. Post-curing with nitrogen improved the degree of conversion, surface hardness, and biocompatibility of 3D-printed dental materials, confirming reduced cytotoxicity without impairing mechanical properties. Nitrogen increased polymerization and decreased harmful monomers, making it ideal for clinical applications in contact with the oral mucosa. Optimizing post-processing steps, such as curing in nitrogen, enhances biocompatibility while maintaining strength and hardness, ensuring better patient care in dental applications. KW - Biocompatibility KW - V-Print KW - Cytotoxicity KW - Nitrogen KW - Dentistry PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654504 DO - https://doi.org/10.1007/s10856-026-07006-5 SN - 1573-4838 VL - 37 IS - 1 SP - 1 EP - 13 PB - Springer Science and Business Media LLC AN - OPUS4-65450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, K. A1 - Mezhov, Alexander A1 - Schmidt, Wolfram T1 - Effect of Polycarboxylate Superplasticizer in Ordinary Portland Cement and Sulfate Resistant Cement N2 - Polycarboxylate superplasticizers (PCE) are the most widely used admixtures in today’s cementitious construction materials. The molecular structure has a decisive influence on the effectiveness of PCE, which also can be tailored to serve in a different cementitious system. The current study investigates the influence of the backbone charge density of PCE on the rheology, hydration kinetics, and adsorption behavior of ordinary Portland cement (OPC) and sulfate-resistant cement (SRC). The results indicate that regardless of the PCE type, OPC requires a higher amount of PCE to be adsorbed to induce changing of rheological parameters and hydration kinetics. Regardless of the cement type, the PCE with a higher charge density exhibits higher adsorption behavior, corresponding to lower viscosity measurement. Compared to OPC, SRC is more sensitive to the introduction of both PCEs and has a lower saturation dosage, indicating that SRC generally provides better workability properties regardless of the PCE. KW - Polycarboxylate superplasticizers (PCE) KW - Sulfate resistant cement (SRC) KW - Rheological KW - Adsorption KW - Cement hydration PY - 2023 DO - https://doi.org/10.1061/JMCEE7.MTENG-15033 SN - 0899-1561 VL - 35 IS - 6 SP - 1 EP - 12 PB - ASCE Libary AN - OPUS4-58244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Cunnigham, P. R. A1 - Shaba, A. F. A1 - Olonade, K. A. A1 - Ndawula, J. A1 - Tawiah, A. T. A1 - Marangu, J. M. A1 - Tlhatlha, Pheladi A1 - Obeng, E. ED - Banhia, N. T1 - Informal Sector Inclusion in Sustainable Concrete Construction in Africa N2 - Concrete used as a construction material is inevitable in Africa’s rapid urban growth, despite its significant contribution to carbon emissions. Hence, best practice concrete with reduced Portland cement clinker needs to be applied. The highly informal nature ofAfrica’s construction sector could impede the implementation of sustainable concrete construction. Although urgent need for economisation unintentionally often leads informal actors to operate according to circularity principles, the sector lacks awareness of climate challenges and incentives for adopting climate-friendly materials and technologies. In addition, the informal sector is prone to fraudulent adulterated materials and components causing challenges for safe and durable construction. The authors elaborate on the crucial role of the informal sector in driving sustainable construction forward, despite the lack of policies and disinterest from regulatory bodies. Solutions through education, communication, and quality control are proposed and discussed. T2 - 77th RILEM Annual Week and the 1st Interdisciplinary Symposium on Smart & Sustainable Infrastructures (ISSSI 2023) CY - Vancouver, Canada DA - 04.09.2023 KW - Cement testing KW - Hydration KW - Economic development KW - Informal sector KW - Cement chemistry PY - 2024 SN - 978-3-031-53391-4 DO - https://doi.org/10.1007/978-3-031-53389-1_47 VL - 48 SP - 506 EP - 520 PB - Springer Nature Switzerland AG CY - Schweiz AN - OPUS4-61586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Kanjee, J. A1 - Motukwa, G. A1 - Olonade, K. A1 - Dodoo, A. T1 - A snapshot review of future‑oriented standards for cement, admixtures, and concrete: How Africa can spearhead the implementation of green urban construction materials N2 - The existing cement and concrete standards are not capable of making full use of the current technology capacity due to strong focus on conventional concrete and thus they are not fit for the current and future challenges of construction industry. The paper highlights shortcomings with regard to the implementation of the existing standards. It can be seen that future-oriented standards are generally required to contribute to a lower-carbon footprint of the industry. These changes are significantly more relevant in sub-Saharan Africa, due to the rapidly increasing urbanisation challenge and the enormous potentials to develop lower-carbon technologies than elsewhere in the world. KW - Future‑oriented standards KW - Green urban construction KW - Cement PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582563 DO - https://doi.org/10.1557/s43580-023-00563-9 SN - 2731-5894 VL - 4 IS - 8 SP - 557 EP - 565 PB - Springer International Publishing CY - Springer Nature Switzerland, Cham AN - OPUS4-58256 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, K. A1 - Mezhov, Alexander A1 - Schmidt, Wolfram T1 - Chemical and thixotropic contribution to the structural build-up of cementitious materials N2 - The structural build-up of fresh cement paste is often considered as a purely thixotropic phenomenon in literature even though cementitious materials undergo a non-reversible hydration process that can have an influence on the structuration process. In the current paper a method is proposed to validate the impact of the non-reversible structural build-up. It is shown that fresh cement paste samples lose their structural gain almost completely due to thixotropy while the structural build-up due to hydration can be observed but occurs in a significantly lower order of magnitude over the course of the first hours of hydration. In addition, it is shown, that the chemical component of the structural build-up accelerates with the onset of the acceleration period of hydration, while its contribution in the entire structural build-up remains constant. KW - Thixotropy KW - Structural build-up KW - Penetration test KW - Rheological properties PY - 2022 DO - https://doi.org/10.1016/j.conbuildmat.2022.128307 SN - 0950-0618 VL - 345 IS - 128307 SP - 1 EP - 10 PB - Elsevier Ltd. AN - OPUS4-58248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Olonade, K. A. A1 - Mbugua, R. N. A1 - Lenz, F. J. A1 - Tchetgnia Ngassam, I. T1 - Bio-Based Rheology Modifiers for High Performance Concrete – Possible Modes of Actions and Case Study for Cassava Starch in West Africa N2 - Polymers that help tailoring rheological properties during the casting process have become inevitable constituents for all kinds of high-performance concrete technologies. Due to lacking industries, these typically crude-oil based admixtures are not readily available in many parts of the world, which limits the implementation of more sustainable high-performance construction technologies in these regions. Alternative polymers, which often demand for less processing, can be derived from local plant-based resources. The paper provides experimental data of flow tests of cement pastes with polysaccharides from Triumfetta pendrata A. Rich, acacia gum and cassava without and in the presence of polycarboxylate ether superplasticizer. The flow tests are amended by observations of the zeta potentials and the hydrodynamic diameters in the presence of and without calcium ions in the dispersion medium. The results show that in the presence of and without calcium ions all polysaccharides provide negative zeta potentials, yet, they affect flowability and thixotropy in different ways. Cassava starch, acacia gum, and the gum of Triumfetta pendrata A. Rich qualified well for robustness improvement, strong stiffening, and additive manufacturing, respectively. The reason for the different effects can be found in their average sizes and size distribution. Due to the promising results, a flow chart for local value chains is derived on the example of yet unused cassava wastes, which can be converted in parallel. T2 - 3rd International Conference on the Application of Superabsorbent Polymers CY - Skukuza, South Africa KW - Admixtures KW - Polysaccharides KW - Rheology KW - Thixotropy KW - Concrete PY - 2020 SN - 978-3-030-33341-6 SN - 978-3-030-33342-3 DO - https://doi.org/10.1007/978-3-030-33342-3_17 SP - 158 EP - 166 PB - Springer AN - OPUS4-58404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bresch, Harald A1 - Hodoroaba, Vasile-Dan A1 - Schmidt, Alexandra A1 - Rasmussen, K. A1 - Rauscher, H. T1 - Counting Small Particles in Electron Microscopy Images — Proposal for Rules and Their Application in Practice N2 - Electron microscopy (EM) is the gold standard for the characterisation of the morphology (size and shape) of nanoparticles. Visual observation of objects under examination is always a necessary first step in the characterisation process. Several questions arise when undertaking to identify and count particles to measure their size and shape distribution. In addition to challenges with the dispersion and identification of the particles, more than one protocol for counting particles is in use. This paper focuses on precise rules for the counting of particles in EM micrographs, as this influences the measurement accuracy of the number of particles, thus implicitly affecting the size values of the counted particles. We review and compare four different, commonly used methods for counting, which we then apply in case studies. The impact of the selected counting rule on the obtained final particle size distribution is highlighted. One main aim of this analysis is to support the application of a specific, well-defined counting approach in accordance with regulatory requirements to contribute to achieving more reliable and reproducible results. It is also useful for the new harmonised measurement procedures for determining the particle size and particle size distribution of nanomaterials. KW - Nano KW - Particle size distribution KW - Nanoparticle KW - Nanomaterial KW - OECD PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551891 DO - https://doi.org/10.3390/nano12132238 SN - 2079-4991 VL - 12 IS - 13 SP - 2238 PB - MDPI CY - Basel AN - OPUS4-55189 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiedensohler, A. A1 - Wiesner, A. A1 - Weinhold, K. A1 - Birmili, W. A1 - Herrmann, M. A1 - Merkel, M. A1 - Müller, T. A1 - Pfeifer, S. A1 - Schmidt, A. A1 - Tuch, T. A1 - Velarde, F. A1 - Quincey, P. A1 - Seeger, Stefan A1 - Nowak, A. T1 - Mobility particle size spectrometers: Calibration procedures and measurement uncertainties N2 - Mobility particle size spectrometers (MPSS) belong to the essential instruments in aerosol science that determine the particle number size distribution (PNSD)in the submicrometer size range. Following calibration procedures and target uncertainties against standards and reference instruments are suggested for a complete MPSS quality assurance program: a) calibration of the CPC counting efficiency curve (within 5% for the plateau counting efficiency; within 1 nm for the 50% detection efficiency diameter), b) sizing calibration of the MPSS, using a certified polystyrene latex (PSL) particle size standard at 203 nm (within 3%), c) intercomparison of the PNSD of the MPSS (within 10% and 20% of the dN/dlogDP concentration for the particle size range 20 – 200 nm and 200 to 800 nm, respectively), and d) intercomparison of the integral PNC of the MPSS (within 10%). Furthermore, following measurement uncertainties have been investigated: a) PSL particle size standards in the range from 100-500nm match within 1% after sizing calibration at 203 nm. b) Bipolar diffusion chargers based on the radioactive nuclides Kr85, Am241 and Ni63 and a new ionizer based on corona discharge follow the recommended bipolar charge distribution, while soft X-ray-based charges may alter faster than expected. c) The use of a positive high voltage supply show a 10% better performance than a negative one. d) The intercomparison of the integral PNC of an MPSS against the total number concentration is still within the target uncertainty at an ambient pressure of approximately 500 hPa. KW - Measurement uncertainties KW - Mobility particle size spectrometer (MPPS) KW - Condensation particle counter (CPC) KW - Calibration PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-425060 DO - https://doi.org/10.1080/02786826.2017.1387229 SN - 1521-7388 VL - 52 IS - 2 SP - 146 EP - 164 PB - Tailor & Francis CY - USA AN - OPUS4-42506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poyraz, Ö. A1 - Schmidt, H. A1 - Seidel, K. A1 - Delißen, Friedmar A1 - Ader, C. A1 - Tenenboim, H. A1 - Goosmann, C. A1 - Laube, B. A1 - Thünemann, Andreas A1 - Zychlinsky, A. A1 - Baldus, M. A1 - Lange, A. A1 - Griesinger, C. A1 - Kolbe, M. T1 - Protein refolding is required for assembly of the type three secretion needle N2 - Pathogenic Gram-negative bacteria use a type three secretion system (TTSS) to deliver virulence factors into host cells. Although the order in which proteins incorporate into the growing TTSS is well described, the underlying assembly mechanisms are still unclear. Here we show that the TTSS needle protomer refolds spontaneously to extend the needle from the distal end. We developed a functional mutant of the needle protomer from Shigella flexneri and Salmonella typhimurium to study its assembly in vitro. We show that the protomer partially refolds from α-helix into β-strand conformation to form the TTSS needle. Reconstitution experiments show that needle growth does not require ATP. Thus, like the structurally related flagellar systems, the needle elongates by subunit polymerization at the distal end but requires protomer refolding. Our studies provide a starting point to understand the molecular assembly mechanisms and the structure of the TTSS at atomic level. PY - 2010 DO - https://doi.org/10.1038/nsmb.1822 SN - 1545-9993 SN - 1545-9985 VL - 17 SP - 788 EP - 792 PB - Nature Publ. Comp. CY - New York, NY, USA AN - OPUS4-21726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chowdhary, S. A1 - Schmidt, R. F. A1 - Sahoo, A. K. A1 - tom Dieck, T. A1 - Hohmann, T. A1 - Schade, B. A1 - Brademann-Jock, Kerstin A1 - Thünemann, Andreas A1 - Netz, R. R. A1 - Gradzielski, M. A1 - Koksch, B. T1 - Rational design of amphiphilic fluorinated peptides: Evaluation of self-assembly properties and hydrogel formation N2 - Advanced peptide-based nanomaterials composed of self-assembling peptides (SAPs) are of emerging interest in pharmaceutical and biomedical applications. The introduction of fluorine into peptides, in fact, offers unique opportunities to tune their biophysical properties and intermolecular interactions. In particular, the degree of fluorination plays a crucial role in peptide engineering as it can be used to control the characteristics of fluorine-specific interactions and, thus, peptide conformation and self-assembly. Here, we designed and explored a series of amphipathic peptides by incorporating the fluorinated amino acids (2S)-4-monofluoroethylglycine (MfeGly), (2S)-4,4-difluoroethylglycine (DfeGly) and (2S)-4,4,4-trifluoroethylglycine (TfeGly) as hydrophobic components. This approach enabled studying the impact of fluorination on secondary structure formation and peptide self-assembly on a systematic basis. We show that the interplay between polarity and hydrophobicity, both induced differentially by varying degrees of side chain fluorination, does affect peptide folding significantly. A greater degree of fluorination promotes peptide fibrillation and subsequent formation of physical hydrogels in physiological conditions. Molecular simulations revealed the key role played by electrostatically driven intra-chain and inter-chain contact pairs that are modulated by side chain fluorination and give insights into the different self-organization behaviour of selected peptides. Our study provides a systematic report about the distinct features of fluorinated oligomeric peptides with potential applications as peptide-based biomaterials. KW - Small-angle X-ray scattering KW - SAXS KW - Amyloid PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553504 DO - https://doi.org/10.1039/D2NR01648F SN - 2040-3364 VL - 14 IS - 28 SP - 10176 EP - 10189 PB - Royal Society of Chemistry AN - OPUS4-55350 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulz, K. A1 - Schmack, R. A1 - Klemm, H. W. A1 - Kabelitz, Anke A1 - Schmidt, T. A1 - Emmerling, Franziska A1 - Kraehnert, R. T1 - Mechanism and kinetics of hematite crystallization in air: Linking bulk and surface models via mesoporous films with defined nanostructure N2 - Iron can form numerous oxides, hydroxides, and oxide−hydroxides. Despite their relevance, many of the transformation processes between these phases are still poorly understood. In particular the crystallization of quasi-amorphous hydroxides and oxide−hydroxides is difficult to assess, since typical diffraction and scattering methods provide only sampleaveraged information about the crystallized phases. We report a new approach for the investigation of the crystallization of oxide−hydroxides. The approach relies on model-type films that comprise a defined homogeneous nanostructure. The nanostructure allows quantitative linking of Information obtained by bulk-averaging diffraction techniques (XRD, SAXS) with locally resolved information, i.e., Domain sizes (SEM, TEM, LEEM) and phase composition (SAED). Using time-resolved imaging and diffraction we deduce mechanism and kinetics for the crystallization of ferrihydrite into hematite. Hematite forms via nucleation of hematite domains and subsequent Domain growth that terminates only upon complete transformation. A Johnson−Mehl−Avrami−Kolmogorov model describes the kinetics over a wide temperature range. The derived understanding enables the first synthesis of ferrihydrite films with ordered mesoporosity and quantitative control over the films’ hematite and ferrihydrite content. KW - Iron oxide KW - Crystallization KW - Mesoporous films KW - Nanostructure PY - 2017 DO - https://doi.org/10.1021/acs.chemmater.6b05185 SN - 0897-4756 SN - 1520-5002 VL - 29 IS - 4 SP - 1724 EP - 1734 AN - OPUS4-39690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Everard, C.D. A1 - Schmidt, Martin A1 - McDonnell, K.P. A1 - Finnan, J. T1 - Heating processes during storage of Miscanthus chip piles and numerical simulations to predict self-ignition N2 - Miscanthus x Giganteus (Miscanthus) energy crop was examined at laboratory scale to assess its self-heating and self-ignition risks during storage. Chipped Miscanthus (18 mm) from February and March harvests, in 2012, were assessed as well as ground Miscanthus (3 mm) from the March harvest. February and March crops had moisture contents of 41.6 and 20.2%, respectively. Self-ignition temperatures were independent of moisture although moisture did affect the time from the beginning of storage until storage temperature was reached. Ground Miscanthus had lower self-ignition temperatures than chipped Miscanthus. Isothermal respirometric tests carried out showed increase risk of self-heating in the February crop compared to the March crop due to increased microbial activity. Numerical simulations were used to determine critical enhanced start temperatures, e.g. caused by microbial decomposition, of the stored Miscanthus. Safe storage conditions have been derived from the investigations. The numerical simulations demonstrated that self-ignition was possible in Miscanthus chip piles with a height greater than 6 m if there was significant heat release from microbiological activity. Reliable assessment of self-heating and self-ignition risks in large scale Miscanthus energy crop clamps or piles are required to prevent losses due to decomposition and fire damage. KW - Miscanthus x Giganteus KW - Hot storage test KW - Respirometric rates KW - Self-heating KW - Self-ignition KW - Numerical simulations KW - Biomass storage PY - 2014 DO - https://doi.org/10.1016/j.jlp.2014.06.003 SN - 0950-4230 SN - 1873-3352 VL - 30 SP - 188 EP - 196 PB - Butterworth CY - Guildford, Surrey AN - OPUS4-31149 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bier, A.K. A1 - Bognitzki, M. A1 - Schmidt, A. A1 - Greiner, A. A1 - Gallo, Emanuela A1 - Klack, Patrick A1 - Schartel, Bernhard T1 - Synthesis, properties, and processing of new siloxane-substituted poly(p-xylylene) via CVD N2 - The synthesis of a disiloxane-functionalized [2.2]paracyclophane and its polymerization to the corresponding siloxane-substituted poly(p-xylylene) via chemical vapor deposition (CVD) has been described. Because of the enhanced solubility of the siloxane substituted poly(p-xylylene) analysis of the molecular structure by NMR, molecular weight, and polydispersity by gel permeation chromatography (GPC), and processing by film casting as well as nanofiber formation by electrospinning was possible. Structural isomers were found by NMR which was expected due to the isomeric mixture of the precursor. High molecular weights at moderate polydispersities were found by GPC which was unexpected for a vapor phase deposition polymerization. The amorphous morphology in combination with a low glass transition temperature led to high elongation at break for the siloxane substituted poly(p-xylylene). Significant difference for the wetting versus water was found for as-deposited films, solution cast films, and nanofibers obtained by electrospinning with contact angles up to 135° close to superhydrophobic behavior. KW - Poly(p-xylylene) KW - Siloxane functionalized PPX KW - Chemical vapor deposition KW - Difunctionalized [2.2]paracyclophanes KW - Gorham process PY - 2012 DO - https://doi.org/10.1021/ma2021369 SN - 0024-9297 SN - 1520-5835 VL - 45 IS - 2 SP - 633 EP - 639 PB - American Chemical Society CY - Washington, DC AN - OPUS4-25466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Everard, C.D. A1 - Finnan, J. A1 - McDonnell, K.P. A1 - Schmidt, Martin T1 - Evaluation of self-heating in Miscanthus x giganteus energy crop clamps and the implications for harvesting time N2 - Miscanthus x giganteus energy crop grown in Ireland was harvested on 21st of February and 28th of March 2012 to examine the effects of harvesting time on self-heating during storage of Miscanthus chips in clamps (98 m³) under weather sheltered conditions. There was a relatively large difference in moisture content, of 21.4%, between Miscanthus crop harvested in February and March (41.6 and 20.2%, respectively). Temperature evolution over a storage period of up to 125 days was monitored at different heights and distances from the centre within the clamps. Maximum temperature in the February constructed clamp reached 69 °C compared to 28 °C in the March constructed clamp. Microbial activity was monitored via carbon dioxide and oxygen gas measurements. The high moisture clamp showed higher microbial activity and a volume yield loss of 4.3% due to decomposition in the top section of the clamp. Quality indices post-storage were also assessed. Calorific values from Miscanthus sampled 1 m below the top surface were similar after storage for both February and March constructed clamps, i.e. 18.52 and 18.70 MJ kg-1, respectively. A reliable assessment of self-heating in Miscanthus chip clamps has important consequences for both self-ignition risk and biomass quality. KW - Self-heating KW - Miscanthus x giganteus KW - Biomass storage KW - Self-ignition KW - Biomass quality PY - 2013 DO - https://doi.org/10.1016/j.energy.2013.06.022 SN - 0360-5442 VL - 58 SP - 350 EP - 356 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-29054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Franco de Carvalho, J. M. A1 - Defàveri, K- A1 - Castro Mendes, J. A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Fiorotti Peixoto, R. A. T1 - Influence of particle size-designed recycled mineral admixtures on the properties of cement-based composites N2 - In this work, engineered recycled mineral admixtures were obtained from four different industrial residues: basic oxygen furnace slag, iron ore tailings, quartz mining tailings and quartzite mining tailings. The grinding performance was evaluated in two different programs and the characterization included chemical and mineralogical composition, particle morphology, and physical properties. Performance evaluations were carried out in blended pastes and mortars, including flow properties, hydration kinetics, soundness, pozzolanic activity, and compressive strength. Coarser-than-cement admixtures allowed better flow performance, greater dimensional stability and more economical production, while finer-thancementn admixtures improved mechanical performance by both filler effect and cementing activity. KW - Engineered recycled mineral admixtures KW - Rheology KW - Hydration kinetics KW - Basic oxygen furnace slag KW - Iron ore tailings KW - Mining tailings PY - 2021 DO - https://doi.org/10.1016/j.conbuildmat.2020.121640 SN - 0950-0618 VL - 272 SP - 1 EP - 13 PB - Elsevier Ltd. AN - OPUS4-58255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kim, K.J. A1 - Unger, Wolfgang A1 - Kim, J.W. A1 - Moon, D.W. A1 - Gross, Thomas A1 - Hodoroaba, Vasile-Dan A1 - Schmidt, Dieter A1 - Wirth, Thomas A1 - Jordaan, W. A1 - van Staden, M. A1 - Prins, S. A1 - Zhang, L. A1 - Fujimoto, T. A1 - Song, X.P. A1 - Wang, H. T1 - Inter-laboratory comparison: quantitative surface analysis of thin Fe-Ni alloy films N2 - An international interlaboratory comparison of the measurement capabilities of four National Metrology Institutes (NMIs) and one Designated Institute (DI) in the determination of the chemical composition of thin Fe-Ni alloy films was conducted via a key comparison (K-67) of the Surface Analysis Working Group of the Consultative Committee for Amount of Substance. This comparison was made using XPS (four laboratories) and AES (one laboratory) measurements. The uncertainty budget of the measured chemical composition of a thin alloy film was dominated by the uncertainty of the certified composition of a reference specimen which had been determined by inductively coupled plasma mass spectrometry using the isotope dilution method. Pilot study P-98 showed that the quantification using relative sensitivity factors (RSFs) of Fe and Ni derived from an alloy reference sample results in much more accurate result in comparison to an approach using RSFs derived from pure Fe and Ni films. The individual expanded uncertainties of the participants in the K-67 comparison were found to be between 2.88 and 3.40 atomic %. The uncertainty of the key comparison reference value (KCRV) calculated from individual standard deviations and a coverage factor (k) of 2 was 1.23 atomic %. KW - Quantification KW - Fe-Ni alloy KW - Uncertainty KW - Key comparison KW - Traceability PY - 2012 DO - https://doi.org/10.1002/sia.3795 SN - 0142-2421 SN - 1096-9918 VL - 44 IS - 2 SP - 192 EP - 199 PB - Wiley CY - Chichester AN - OPUS4-24505 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, B.V.K.J. A1 - Fechler, N. A1 - Falkenhagen, Jana A1 - Lutz, J.-F. T1 - Controlled folding of synthetic polymer chains through the formation of positionable covalent bridges N2 - Covalent bridges play a crucial role in the folding process of sequence-defined biopolymers. This feature, however, has not been recreated in synthetic polymers because, apart from some simple regular arrangements (such as block co-polymers), these macromolecules generally do not exhibit a controlled primary structure—that is, it is difficult to predetermine precisely the sequence of their monomers. Herein, we introduce a versatile strategy for preparing foldable linear polymer chains. Well-defined polymers were synthesized by the atom transfer radical polymerization of styrene. The controlled addition of discrete amounts of protected maleimide at precise times during the synthesis enabled the formation of polystyrene chains that contained positionable reactive alkyne functions. Intramolecular reactions between these functions subsequently led to the formation of different types of covalently folded polymer chains. For example, tadpole (P-shaped), pseudocyclic (Q-shaped), bicyclic (8-shaped) and knotted (α-shaped) macromolecular origamis were prepared in a relatively straightforward manner. KW - Copolymerization KW - Chain folding KW - SEC KW - NMR KW - FT-IR KW - LAC KW - MALDI PY - 2011 DO - https://doi.org/10.1038/NCHEM.964 SN - 1755-4330 SN - 1755-4349 VL - 3 SP - 234 EP - 238 PB - Nature Publishing Group CY - London, UK AN - OPUS4-23888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -