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 - BOOK A1 - Maiwald, Michael A1 - Bassler, M. A1 - Deilmann, M. A1 - Ens, W. A1 - Frenzel, F. A1 - Gerlach, M. A1 - Großmann, J. A1 - Grümbel, F. A1 - Heisterkamp, M. A1 - Kaiser, U. A1 - Lambrecht, A. A1 - Ohlenkamp, R. A1 - Pötter, T. A1 - Pyka, P. A1 - Roos, E. A1 - Schmidt, A. A1 - Schünemann, U. A1 - Theuer, M. A1 - Tukle, A. A1 - Weber, N. T1 - Technologie-Roadmap „Prozess-Sensoren 2027+“ N2 - Die Technologie-Roadmap „Prozess-Sensoren 2027+“ ist eine Weiterentwicklung vorgängiger Technologie-Roadmaps. Im Zentrum dieser Roadmaps stehen Sensoren zur Erfassung von physikalischen und chemischen Messgrößen mittels spezifischer und unspezifischer Messverfahren, die zur Steuerung und dem besseren Verständnis von Prozessen dienen. Die Roadmap fasst die gemeinsame Technologie- und Marktsicht von Anwendern, Herstellern und Forschungseinrichtungen im Bereich Prozess-Sensorik in der verfahrenstechnischen Industrie zusammen. Sie beschreibt die wesentlichen Trends im Bereich Prozess-Sensorik und künftige Handlungsbedarfe für Hersteller, Anwender sowie für Einrichtungen der Forschung und Lehre. Für die aktuellen und zukünftigen Anforderungen an Prozess-Sensoren werden 19 Thesen formuliert. Die Thesen basieren auf den Thesen der vorangegangenen Roadmaps, wobei die aus heutiger Sicht erforderlichen Anpassungen, Ergänzungen und teilweise auch Streichungen vorgenommen wurden. Die Thesen sind in 5 Themencluster eingeordnet. Digitalisierung und Nachhaltigkeit sind übergreifende Kernthemen der künftigen Entwicklung. KW - Technologie-Roadmap Prozess-Sensoren KW - Prozessindustrie KW - Prozessanalytik KW - Sensorik KW - Digitalisierung KW - NAMUR PY - 2021 SP - 1 EP - 63 AN - OPUS4-53741 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haist, M. A1 - Link, J. A1 - Nicia, D. A1 - Leinitz, Sarah A1 - Baumert, C. A1 - von Bronk, T. A1 - Cotardo, D. A1 - Eslami Pirharati, M. A1 - Fataei, S. A1 - Garrecht, H. A1 - Gehlen, C. A1 - Hauschildt, I. A1 - Ivanova, I. A1 - Jesinghausen, S. A1 - Klein, C. A1 - Krauss, H.-W. A1 - Lohaus, L. A1 - Lowke, D. A1 - Mazanec, O. A1 - Pawelczyk, S. A1 - Pott, U. A1 - Radebe, N. W. A1 - Riedmiller, J. J. A1 - Schmid, H.-J. A1 - Schmidt, Wolfram A1 - Secrieru, E. A1 - Stephan, D. A1 - Thiedeitz, M. A1 - Wilhelm, M. A1 - Mechtcherine, V. T1 - Interlaboratory study on rheological properties of cement pastes and reference substances: comparability of measurements performed with different rheometers and measurement geometries N2 - This paper presents the results of an interlaboratory study of the rheological properties of cement paste and ultrasound gel as reference substance. The goal was to quantify the comparability and reproducibility of measurements of the Bingham parameters yield stress and plastic viscosity when measured on one specific paste composition and one particular ultrasound gel in different laboratories using different rheometers and measurement geometries. The procedures for both in preparing the cement paste and carrying out the rheological measurements on cement paste and ultrasound gel were carefully defined for all of the study’s participants. Different conversion schemes for comparing the results obtained with the different measurement setups are presented here and critically discussed. The procedure proposed in this paper ensured a reasonable comparability of the results with a coefficient of variation for the yield stress of 27% and for the plastic viscosity of 24%, despite the individual measurement series’ having been performed in different labs with different rheometers and measurement geometries. KW - Rheometry KW - Rheology KW - Interlaboratory test KW - Test setup KW - Testing procedure KW - Cement paste KW - Ultrasound gel PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511220 DO - https://doi.org/10.1617/s11527-020-01477-w SN - 1871-6873 VL - 53 IS - 4 SP - 92 PB - Rilem AN - OPUS4-51122 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Ballio, F. A1 - Chatzi, E. A1 - Cigada, A. A1 - Darò, P. A1 - Elfgren, L. A1 - Gentile, C. A1 - Górski, M. A1 - Küttenbaum, Stefan A1 - Limongelli, M. P. A1 - Mancini, G. A1 - Oliveira, S. A1 - Rasol, M. A1 - Schmidt, F. A1 - Shan, J. A1 - Sousa, H. A1 - Torrent, R. A1 - Ueda, T. A1 - Verstrynge, E. T1 - Chapter 6: Case studies N2 - This chapter contains a selection of case studies that show the implementation of the methods and tools that have been described in the previous chaprters of fib Bulletin 109 on actual large-scale structures. KW - Structural engineering KW - Structural Health Monitoring KW - Non-destructive testing KW - Static and dynamic reassessment KW - Existing structures PY - 2023 SN - 978-2-88394-172-4 DO - https://doi.org/10.35789/fib.BULL.0109.Ch06 SN - 1562-3610 VL - fib Bulletin 109 SP - 104 EP - 126 PB - Fédération internationale du béton (fib) CY - Lausanne AN - OPUS4-59341 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 - RPRT A1 - Ebert, H.-P. A1 - Reichenauer, G. A1 - Brandt, R. A1 - Braxmeier, S. A1 - Bauer, T. A1 - Tamme, R. A1 - Langer, W. A1 - Hudler, B. A1 - Christ, M. A1 - Sextl, G. A1 - Müller, G. A1 - Helbig, U. A1 - Houbertz, R. A1 - Voigt, W. A1 - Schmidt, H. A1 - Zehl, T. A1 - Mach, Reinhard A1 - Maneck, Heinz-Eberhard A1 - Meyer-Plath, Asmus A1 - Oleszak, Franz A1 - Keuper, M. A1 - Reisert, M. A1 - Burkhardt, H. A1 - Günther, E. A1 - Mehling, H. T1 - Netzwerk zur Überwindung grundlegender Probleme bei der Entwicklung hocheffizienter Latentwärmespeicher auf Basis anorganischer Speichermaterialien KW - Latentwärmespeicher KW - Materialforschung KW - Plasmaverfahren KW - Graphit PY - 2008 SN - 978-3-00-024699-9 SP - 1 EP - 217 CY - Würzburg AN - OPUS4-18273 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H.R. A1 - Rabenstein, M. A1 - Langanke, D. A1 - Schwarz, G. A1 - Schmidt, M. A1 - Maskos, M. A1 - Krüger, Ralph-Peter T1 - Ring-closing polycondensations N2 - The role of cyclization in polycondensations is discussed for two different scenarios: thermodynamically-controlled polycondensation (TCPs) on the one hand and kinetically-controlled polycondensations (KCPs) on the other. The classical Carothers–Flory theory of step-growth polymerization does not include cyclization reactions. However, TCPs involve the formation of cycles via ‘back-biting degradation’, and when the ring–chain equilibrium is on the side of the cycles the main reaction products of the TCP will be cyclic oligomers. Two groups of examples are discussed: polycondensations of salicyclic acid derivatives (e.g. aspirin) and polycondensations of dibutyltin derivatives with long {alpha}-, {omega}-diols or dicarboxylic acids. Furthermore, various kinetically-controlled syntheses of polyesters and polyamides were studied and carefully optimized in the direction of high molecular weights. High fractions of cyclic oligomers and polymers were found by MALDI-TOF mass spectrometry, and their fractions increased with optimization of the process for molecular weight. These results disagree with the Carothers–Flory theory but agree with the theoretical background of the Ruggli–Ziegler dilution method (RZDM). When poly(ether-sulfone)s were prepared from 4,4'-difluorodiphenylsulfone and silylated bisphenol-A two different scenarios were found. With CsF as catalyst at a temperature of more than 145°C cyclic oligoethers were formed under thermodynamic control. When the polycondensation was promoted with K2CO3 in N-methylpyrolidone at ?145°C the formation of cyclic oligoethers and polyethers occurred under kinetic control. A new mathematical formula is presented correlating the average degree of polymerization with the conversion and taking into account the competition between cyclization and propagation. PY - 2001 DO - https://doi.org/10.1088/0954-0083/13/2/312 SN - 0954-0083 SN - 1361-6412 VL - 13 SP - S123 EP - S136 PB - Sage Publ. CY - London AN - OPUS4-2178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Göbel, E. O. A1 - Hasche, K. A1 - Ulm, G. A1 - Krumrey, M. A1 - Ade, G. A1 - Stümpel, J. A1 - Herrmann, K. A1 - Koenders, L. A1 - Thomsen-Schmidt, P. A1 - Pohlenz, F. A1 - Xu, M. A1 - Dai, G. A1 - Hoffmann, K.-P. A1 - Busch, I. A1 - Frank, W. A1 - Procop, M. A1 - Beck, Uwe T1 - Kalibrierte Schichtdicken-Maßverkörperungen für Nanometerschichten, Teilvorhaben - Kalibrierung von Schichtdicken-Maßverkörperungen im Nanometerbereich - Abschlussbericht des BMBF Verbundvorhabens 13N7704 - 13N77041 KW - Schichtdicke KW - Nanometerbereich PY - 2003 UR - http://edok01.tib.uni-hannover.de/edoks/e01fb02/373214030.pdf SP - 1 EP - 131 PB - Physikalisch-Technische Bundesanstalt CY - Dresden AN - OPUS4-25428 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Henning, L. M. A1 - Diaz Cubas, D. A1 - Colmenares, M. G. A1 - Schmidt, J. A1 - Bekheet, M. F. A1 - Pauw, Brian Richard A1 - Gurlo, A. A1 - Simon, U. T1 - High specific surface area ordered mesoporous silica COK-12 with tailored pore size N2 - Ordered mesoporous silica materials such as COK-12, analogous to the well-known SBA-15, are characterized by high surface areas and unique features such as defined pore sizes in the meso-size range and high pore ordering. The aim of this work was to prove the washing step and choice of calcination and aging temperature during the COK-12 synthesis as effective tools in tailoring, markedly improving the specific surface area, pore size, and pore volume. By controlling the aging temperature, the pore size was linearly adjusted between 5.7 and 8.1 nm, while preserving the hexagonal ordering of the pores. The synthesized COK-12 powders possess pore volumes and specific surface areas up to 1.23 cm3 g−1 and 860m2 g−1, respectively, which is markedly higher than what has previously been reported about COK-12. The presented results and the environmentally friendly character of the synthesis will make COK-12 more interesting for future adaption to the industrial processes, for example in catalysis, adsorption, or drug delivery. KW - Ordered mesoporous silica KW - Pore size tailoring KW - High specific surface area KW - SAXS KW - Small angle scattering PY - 2019 DO - https://doi.org/10.1016/j.micromeso.2019.01.050 SN - 1387-1811 VL - 280 SP - 133 EP - 143 PB - Elsevier AN - OPUS4-47378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wolf, M. E. A1 - Vickery, W. M. A1 - Swift-Ramirez, W. A1 - Arnold, A. M. A1 - Orlando, J. D. A1 - Schmidt, S. J. A1 - Liu, Y. A1 - Er, Jasmin A1 - Schusterbauer, Robert A1 - Ahmed, R. A1 - Nickl, Philip A1 - Radnik, Jörg A1 - Donskyi, Ievgen A1 - Sydlik, S. A. T1 - The Mitsunobu reaction for the gentle covalent attachment of biomolecules to graphene oxide N2 - Graphene oxide (GO) has emerged as a promising biomaterial as it is easily and cheaply synthesized, strong, cytocompatible, osteoinductive, and has a well-characterized aqueous degradation pathway. It is also a great substrate for functionalization with biomolecules such as proteins, peptides, and small molecules that can enhance or add bioactivity. Covalent chemical linkages as opposed to typical noncovalent association methods are preferable so that the biomolecules do not quickly diffuse away or face replacement by other proteins, which is critical in long time scale applications like bone regeneration. However, covalent chemistry tends to carry a drawback of harsh reaction conditions that can damage the structure, conformation, and therefore function of a delicate biomolecule like a protein. Here, the Mitsunobu reaction is introduced as a novel method of covalently attaching proteins to graphene oxide. It features gentle reaction conditions and has the added benefit of utilizing the plentiful basal plane alcohol functionalities on graphene oxide, allowing for high yield protein functionalization. The amino acid Glycine (G), the protein bovine serum albumin (BSA), and the small molecule SVAK-12 are utilized to create the three Mitsunobu Graphene (MG) materials G-MG, BSA-MG, and SVAK-MG that demonstrate the wide applicability of this functionalization method. KW - Graphene oxide KW - Mitsunobu reaction KW - Covalent attachment KW - Bovine serum albumin KW - Macrophage polarization KW - Osteogenesis PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630483 DO - https://doi.org/10.1016/j.carbon.2025.120221 VL - 238 SP - 1 EP - 15 PB - Elsevier Ltd. AN - OPUS4-63048 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kondo, M. A1 - Melzer, Michael A1 - Karnaushenko, D. A1 - Uemura, T. A1 - Yoshimoto, S. A1 - Aklyama, M. A1 - Noda, Y. A1 - Araki, T. A1 - Schmidt, O. G. A1 - Sekitani, T. T1 - Imperceptible magnetic sensor matrix system integrated with organic driver and amplifier circuits N2 - Artificial electronic skins (e-skins) comprise an integrated matrix of flexible devices arranged on a soft, reconfigurable surface. These sensors must perceive physical interaction spaces between external objects and robots or humans. Among various types of sensors, flexible magnetic sensors and the matrix configuration are preferable for such position sensing. However, sensor matrices must efficiently map the magnetic field with real-time encoding of the positions and motions of magnetic objects. This paper reports an ultrathin magnetic sensor matrix system comprising a 2 × 4 array of magnetoresistance sensors, a bootstrap organic shift register driving the sensor matrix, and organic signal amplifiers integrated within a single imperceptible platform. The system demonstrates high magnetic sensitivity owing to the use of organic amplifiers. Moreover, the shift register enabled real-time mapping of 2D magnetic field distribution. KW - Imperceptible electronics KW - Magnetic sensor system KW - Electronic skin KW - Organic electronics KW - Giant magnetoresistance PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503855 DO - https://doi.org/10.1126/sciadv.aay6094 SN - 2375-2548 VL - 6 IS - 4 SP - Paper eaay6094, 1 EP - 10 PB - American Association for the Advancement of Science AN - OPUS4-50385 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 - CONF A1 - Schneider, M. A1 - Schlingmann, T. A1 - Schmidt, J. A1 - Bettge, Dirk A1 - Hilgenberg, Kai A1 - Binder, M. A1 - Klöden, B. T1 - A Round Robin Test To Investigate The Printing Quality Of PBF LB/M Processed AlSi10Mg N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail. T2 - World PM2022 CY - Lyon, France DA - 09.10.2022 KW - Additive manufacturing KW - AlSi10Mg KW - Laser powder bed fusion KW - Round robin KW - Reproducibility PY - 2022 AN - OPUS4-56303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, M. A1 - Schlingmann, T. A1 - Schmidt, J. A1 - Bettge, Dirk A1 - Hilgenberg, Kai A1 - Binder, M. A1 - Klöden, B. T1 - A Round Robin Test To Investigate The Printing Quality Of PBF-LB/M Processed AlSi10Mg N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail. T2 - World PM2022 CY - Lyon, France DA - 09.10.2022 KW - Additive manufacturing KW - Round robin KW - Reproducibility KW - Laser powder bed fusion KW - AlSi10Mg PY - 2022 SN - 978-1-899072-54-5 SP - 1 EP - 10 PB - European Powder Metallurgy Association (EPMA) AN - OPUS4-56304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eisenreich, F. A1 - Kathan, M. A1 - Dallmann, A. A1 - Ihrig, S. P. A1 - Schwaar, Timm A1 - Schmidt, B. M. A1 - Hecht, S. T1 - A photoswitchable catalyst system for remote-controlled (co)polymerization in situ N2 - The fundamental properties of a polymeric material are ultimately governed by its structure, which mainly relies on monomercomposition and connection, topology, chain length, and polydispersity. Thus far, these structural characteristics are typicallyset ex situ by the specific polymerization procedure, eventually limiting the future design space for the creation of moresophisticated polymers. Herein, we report on a single photoswitchable catalyst system, which enables in situ remote controlover the ring-opening polymerization of l-lactide and further allows regulation of the incorporation of trimethylene carbonateand δ -valerolactone monomers in copolymerizations. By implementing a phenol moiety into a diarylethene-type structure,we exploit light-induced keto–enol tautomerism to switch the hydrogen-bonding-mediated monomer activation reversiblyON and OFF. This general and versatile principle allows for exquisite external modulation of ground-state catalysis of a livingpolymerization process in a closed system by ultraviolet and visible light and should thereby facilitate the generation of newpolymer structures. KW - Polymers PY - 2018 DO - https://doi.org/10.1038/s41929-018-0091-8 SN - 2520-1158 VL - 1 IS - 7 SP - 516 EP - 522 PB - Nature CY - London AN - OPUS4-45407 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sprachmann, J. A1 - Wachsmuth, T. A1 - Bhosale, M. A1 - Burmeister, D. A1 - Smales, Glen Jacob A1 - Schmidt, M. A1 - Kochovski, Z. A1 - Grabicki, N. A1 - Wessling, R. A1 - List-Kratochvil, E. J. W. A1 - Esser, B. A1 - Dumele, O. T1 - Antiaromatic Covalent Organic Frameworks Based on Dibenzopentalenes N2 - Despite their inherent instability, 4n π systems have recently received significant attention due to their unique optical and electronic properties. In dibenzopentalene (DBP), benzanellation stabilizes the highly antiaromatic pentalene core, without compromising its amphoteric redox behavior or small HOMO−LUMO energy gap. However, incorporating such molecules in organic devices as discrete small molecules or amorphous polymers can limit the performance (e.g., due to solubility in the battery electrolyte solution or low internal surface area). Covalent organic frameworks (COFs), on the contrary, are highly ordered, porous, and crystalline materials that can provide a platform to align molecules with specific properties in a well-defined, ordered environment. We synthesized the first antiaromatic framework materials and obtained a series of three highly crystalline and porous COFs based on DBP. Potential applications of such antiaromatic bulk materials were explored: COF films show a conductivity of 4 × 10−8 S cm−1 upon doping and exhibit photoconductivity upon irradiation with visible light. Application as positive electrode materials in Li-organic batteries demonstrates a significant enhancement of performance when the antiaromaticity of the DBP unit in the COF is exploited in its redox activity with a discharge capacity of 26 mA h g−1 at a potential of 3.9 V vs. Li/Li+ . This work showcases antiaromaticity as a new design principle for functional framework materials. KW - SAXS KW - MOUSE KW - Covalent Organic Frameworks KW - Batteries PY - 2023 DO - https://doi.org/10.1021/jacs.2c10501 SP - 1 EP - 12 PB - ACS Publications AN - OPUS4-56958 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bühler, M. M. A1 - Hollenbach, P. A1 - Michalski, A. A1 - Meyer, S. A1 - Birle, E. A1 - Off, R. A1 - Lang, Ch. A1 - Schmidt, Wolfram A1 - Cudmani, R. A1 - Fritz, O. A1 - Baltes, G. A1 - Kortmann, G. T1 - The Industrialisation of Sustainable Construction: A Transdisciplinary Approach to the Large-Scale Introduction of Compacted Mineral Mixtures (CMMs) into Building Construction N2 - Abstract: Increasing demand for sustainable, resilient, and low-carbon construction materials has highlighted the potential of Compacted Mineral Mixtures (CMMs), which are formulated from various soil types (sand, silt, clay) and recycled mineral waste. This paper presents a comprehensive inter- and transdisciplinary research concept that aims to industrialise and scale up the adoption of CMM-based construction materials and methods, thereby accelerating the construction industry’s systemic transition towards carbon neutrality. By drawing upon the latest advances in soil mechanics, rheology, and automation, we propose the development of a robust material properties database to inform the design and application of CMM-based materials, taking into account their complex, time-dependent behaviour. Advanced soil mechanical tests would be utilised to ensure optimal performance under various loading and ageing conditions. This research has also recognised the importance of context-specific strategies for CMM adoption. We have explored the implications and limitations of implementing the proposed framework in developing countries, particularly where resources may be constrained. We aim to shed light on socio-economic and regulatory aspects that could influence the adoption of these sustainable construction methods. The proposed concept explores how the automated production of CMM-based wall elements can become a fast, competitive, emission-free, and recyclable alternative to traditional masonry and concrete construction techniques. We advocate for the integration of open-source digital platform technologies to enhance data accessibility, processing, and knowledge acquisition; to boost confidence in CMM-based technologies; and to catalyse their widespread adoption. We believe that the transformative potential of this research necessitates a blend of basic and applied investigation using a comprehensive, holistic, and transfer-oriented methodology. Thus, this paper serves to highlight the viability and multiple benefits of CMMs in construction, emphasising their pivotal role in advancing sustainable development and resilience in the built environment. KW - Decarbonisation KW - Circular economy KW - Recycled materials KW - Demolition wastes KW - Low-carbon construction KW - Building with earth KW - Compressed earth KW - Rammed earth KW - Sustainable construction PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583260 DO - https://doi.org/10.3390/su151310677 VL - 15 IS - 13 SP - 1 EP - 25 PB - MDPI AN - OPUS4-58326 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Gogates, G. A1 - Eberhard, H. A1 - Pedersen, P. L. A1 - Ellison, S. A1 - Schmidt, Anita A1 - Abrantes da Costa, M. E. A1 - Holmgren, M. A1 - Tasic, T. A1 - Hald, J. T1 - Guidance for the Management of Computers and Software in Laboratories with Reference to ISO/IEC 17025:2005 N2 - This guideline is intended to be used as an aid to laboratories when they are managing the use of software and computers with respect to the requirements of ISO/IEC 17025. The working group consisted of representatives from accreditation bodies and conformity assessment operators, specifically laboratory organisations, but also included certification bodies, inspection bodies and metrology institutes. KW - Software KW - Laboratory KW - ISO/IEC 17025 PY - 2006 UR - http://www.eurolab.org/documents/2-2006.pdf VL - 2/2006 SP - 1 EP - 31 PB - EUROLAB CY - Paris AN - OPUS4-35414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lu, Z. C. A1 - Haist, M. A1 - Ivanov, D. A1 - Jakob, C. A1 - Jansen, D. A1 - Schmid, M. A1 - Kißling, P. A. A1 - Leinitz, Sarah A1 - Link, J. A1 - Mechtcherine, V. A1 - Neubauer, J. A1 - Plank, J. A1 - Schmidt, Wolfram A1 - Schilde, C. A1 - Schröfl, C. A1 - Sowoidnich, T. A1 - Stephan, D. T1 - Characterization data of reference cement CEM III/A 42.5N used for priority program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials" N2 - Two types of cements were selected as the reference cement in the priority program 2005 of the German Research Foundation (DFG SPP 2005). A thorough characterization of CEM I 42.5 R has been made in a recent publication. In this paper, the characterization data of the other reference cement CEM III/A 42.5 N are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The characterization data of the slag, which is the second main constituent of this specific cement besides the clinker, are presented independently. For all data received, the mean values and the corresponding errors were calculated. The data shall be used for the ongoing research within the priority program. Also, researchers from outside this priority program can benefit from these data if the same materials are used. KW - Cement KW - Slag KW - Characterization KW - DFG SPP 2005 PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568980 DO - https://doi.org/10.1016/j.dib.2020.105524 SN - 2352-3409 VL - 30 SP - 1 EP - 14 PB - Elsevier CY - Amsterdam AN - OPUS4-56898 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thiedeitz, M. A1 - Schmidt, Wolfram A1 - Härder, M. A1 - Kränkel, T. T1 - Performance of rice husk ash as supplementary cementitious material after production in the field and in the lab N2 - Supplementary cementitious materials (SCM) can reduce the total amount of Portland cement clinker in concrete production. Rice husk ashes (RHA) can be converted from an agricultural by-product to a high-performance concrete constituent due to a high amount of reactive silica with pozzolanic properties if they are burnt under controlled conditions. The way and duration of combustion, the cooling process as well as the temperature have an effect on the silica form and thus, the chemical and physical performance of the RHA. Various studies on the best combustion technique have been published to investigate the ideal combustion techniques. Yet, the process mostly took place under laboratory conditions. Investigating the difference between the performance of RHA produced in a rural environment and laboratory conditions is useful for the assessment and future enhancement of RHA production, and its application both as building material, for example in rural areas where it is sourced in large quantities, and as additive for high performance concrete. Thus, the paper presents a comparison between RHA produced under rudimentary conditions in a self-made furnace in the rural Bagamoyo, Tanzania and under controlled laboratory conditions at the Technical University of Munich, Germany, with different combustion methods and temperatures. In a second step, RHA was ground to reach particle size distributions comparable to cement. In a third step, cement pastes were prepared with 10%, 20% and 40% of cement replacement, and compared to the performance of plain and fly ash blended cement pastes. The results show that controlled burning conditions around 650 °C lead to high reactivity of silica and, therefore, to good performance as SCM. However, also the RHA burnt under less controlled conditions in the field provided reasonably good properties, if the process took place with proper burning parameters and adequate grinding. The knowledge can be implemented in the field to improve the final RHA performance as SCM in concrete. KW - Rice husk ash KW - Agricultural by-product KW - Supplementary cementitious material KW - Waste management KW - Carbon dioxide emissions PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568953 DO - https://doi.org/10.3390/ma13194319 SN - 1996-1944 VL - 13 SP - 1 EP - 17 PB - MDPI CY - Basel AN - OPUS4-56895 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fini, E. H. A1 - Poulikakos, L. A1 - de Claville Christiansen, J. A1 - Schmidt, Wolfram A1 - Parast, M. M. T1 - Toward sustainability in the built environment: An integrative approach N2 - The built environment significantly impacts the health of individuals and populations in various ways. The health and durability of the built environment are intertwined with availability ofnaturally occurring and man-made resources and their supply chains. Therefore, resource con­ servation is a key to ensure sustainability of built environments. Many industrial wastes can be turned into valuable resources for reuse in construction of the built environment. For instance, biowaste (woody/ leafy biomass and animal waste) have been used to make construction adhesives (Fini et al., 2011), some urban wastes have been used in road construction (Poulikakos et al., 2017; Schmidt et al., 2021), end of life plastics and polymers have made their way to roadway construction, bio-oils and algae harvested from wastewater treatment plants has been used to make antiaging for outdoor building elements to mitigate UV aging (Kabir et al., 2021); sulfur has been used as an extender in asphalt and recycled mineral powders such as silica and alumina have been used to increase strength and durability against acidic compounds (Fini et al., 2019). These are just a few examples of recycling venues with beneficial uses in the built environment. The construction and operation of the built environment and the traffic that it attracts or facilitates significantly contribute to the emis­ sion of greenhouse gasses (GHG) and cause air pollution. The direct and indirect impacts of GHG and air pollutants on the environment and so­ cieties have been weil established. The built environment can be used as a powerful platform not only for recycling and resource conservation but also to remove near-ground gaseous contaminants. This can be done via tailored design and engineering of adsorptive construction materials via recycling of waste materials. For instance, advanced sorbent systems can be made for removing C02, H2S, and formaldehyde from air. This re­ quires tailored sorbent design, topology optimization, and catalytic conversion of collected gaseous compounds to name a few. This special issue covers innovative materials, methods, and man­ agement practices which aim to simultaneously address durability ofthe built environment, air quality, resource conservation, and supply chain resilience. Such innovative materials, methods, and management prac­ tices will transform the built environment into not only an active contributor to no waste, no pollution for healthy environment, but also a medium that converts the waste and pollution into beneficial products for use in the built environment, thereby promoting resource conser­ vation. Followings are examples of topics that the special issue is interested in: • Venuses to advance resource conservation specifically via novel ap­ proaches in the built environment. • Innovative construction materials for passive or active adsorption of harmful gaseous emissions to conserve air, energy, and water. • Advanced materials, methods, and management practices to pro­ mote well-being of the built environment. • Smart buildings to promote resource conservation. • Research convergence in the built environment for zero waste, zero pollution economy. KW - Impacts KW - Resource PY - 2021 DO - https://doi.org/10.1016/j.resconrec.2021.105676 VL - 172 SP - 1 EP - 2 PB - Elsevier AN - OPUS4-58402 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fini, E. A1 - Kazemi, M. A1 - Poulikakos, L. A1 - de Claville Christiansen, J. A1 - Schmidt, Wolfram A1 - Parast, M. T1 - Toward Sustainability in the Built Environment: An Integrative Approach N2 - The built environment refers to the human-made surroundings within which people reside and work, including buildings, green spaces, streets, urban centers, and critical infrastructure like water and energy networks. This sector holds a pivotal place in the global economy, contributing to approximately 10 percent of the global gross domestic product (Tokede et al., 2022). However, its importance extends far beyond monetary metrics, exerting a profound influence on emissions, resource utilization, and land use transformations across various industries. Notably, this sector stands responsible for more than one-third of global final energy consumption, underscoring its substantial contribution of nearly 40 % to global energy-related greenhouse gas emissions while consuming nearly 60 percent of the world’s total raw materials (Tokede et al., 2022; Thiedeitz et al., 2022). The recent surge in population and urbanization has exacerbated diverse challenges associated with the built environment, such as climate change, pollution, resource depletion, energy inefficiency, and economic instability (Corona et al., 2019). Addressing these multifaceted issues is crucial for fostering sustainability within the built environment. Accelerating the transition toward creating built environments that are circular, well-balanced, inclusive, and resilient, while achieving net� zero emissions, stands as a paramount necessity. This shift is vital to accommodate the future spatial requirements and combat global warming, particularly in light of the rapid urbanization observed in developing nations. One effective strategy for advancing sustainability within the built environment involves material conservation through engineering approaches. A key facet of this approach involves the judicious utilization of engineered waste materials, such as waste plastics, recycled concrete aggregates, and recycled asphalt, among others. These materials can be efficiently employed, accompanied by streamlined resource management practices, to mitigate resource depletion and curtail the release of toxic pollutants typically associated with conventional material production. Furthermore, the customization of design and engineering processes for adsorptive waste materials, exemplified by zeolites, can play a pivotal role in removing gaseous pollutants present in the vicinity. This comprehensive approach is essential for addressing the multifaceted challenges posed by resource scarcity and accumulating waste materials, while simultaneously nurturing sustainable development (Fini et al., 2021). Therefore, the development of practical methods and tools to facil� itate the incorporation of resource conservation and recycling into the establishment of sustainable built environments becomes an urgent imperative. The objective of this special issue is to demonstrate the myriad opportunities for enhancing the sustainability and health of the built environment. This is accomplished through the presentation of novel perspectives, data, models, frameworks, and innovative approaches designed to prevent or mitigate long-term unintended consequences. The overarching goal is to integrate sustainable practices into the fabric of the built environment and actively contribute to the global pursuit of carbon neutrality. By advancing strategies and approaches conducive to sustainable built environments, we strive to deepen our understanding of the most favorable pathways to toward achieving lowcarbon development. Moreover, these endeavors bolster resilience in the face of the profound challenges posed by the rapid onset of climate change. This special issue comprises 21 articles, collectively illuminating the vast potential to enhance the sustainability and health of the built environment. These articles introduce fresh insights, new datasets, nuanced models, and robust frameworks, all dedicated to fortifying the sustainability and health aspects of the built environment. Additionally, this special issue serves as a platform for highlighting innovative approaches geared toward averting or mitigating undesirable long-term consequences. Notably, these articles coalesce around four central themes: (1) Materials Aspects of Sustainability, (2) Management Aspects of Sustainability, (3) Technology Aspects of Sustainability, and (4) Health Aspects of Sustainability. Overall, this special issue reflects the most recent scientific advances in constructing a more sustainable, carbon-neutral future. KW - Recycling KW - Conservation KW - Resources PY - 2024 DO - https://doi.org/10.1016/j.resconrec.2023.107241 SN - 0921-3449 VL - 201 SP - 1 EP - 4 PB - Elsevier B.V. AN - OPUS4-61561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pott, U. A1 - Crasselt, Claudia A1 - Fobbe, N. A1 - Haist, M. A1 - Heinemann, M. A1 - Hellmann, S. A1 - Ivanov, D. A1 - Jakob, C. A1 - Jansen, D. A1 - Lei, L. A1 - Li, R. A1 - Link, J. A1 - Lowke, D. A1 - Mechtcherine, V. A1 - Neubauer, J. A1 - Nicia, D. A1 - Plank, J. A1 - Reißig, S. A1 - Schäfer, T. A1 - Schilde, C. A1 - Schmidt, Wolfram A1 - Schröfl, C. A1 - Sowoidnich, T. A1 - Strybny, B. A1 - Ukrainczyk, N. A1 - Wolf, J. A1 - Xiao, P. A1 - Stephan, D. T1 - Characterization data of reference materials used for phase II of the priority program DFG SPP 2005 “Opus Fluidum Futurum –Rheology of reactive, multiscale, multiphase construction materials” N2 - A thorough characterization of base materials is the prereq- uisite for further research. In this paper, the characterization data of the reference materials (CEM I 42.5 R, limestone pow- der, calcined clay and a mixture of these three components) used in the second funding phase of the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented under the aspects of chemical and min- eralogical composition as well as physical and chemical properties. The data were collected based on tests performed by up to eleven research groups involved in this cooperative program. KW - Portland cement KW - Limestone powder KW - Calcined clay KW - Sustainable cement KW - DFG SPP 2005 PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569913 DO - https://doi.org/10.1016/j.dib.2023.108902 VL - 47 SP - 1 EP - 19 PB - Elsevier AN - OPUS4-56991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bugel, S. A1 - Hahnel, M. A1 - Kunde, T. A1 - de Sousa Amadeu, Nader A1 - Sun, Y. A1 - Spieß, A. A1 - Beglau, T. H. Y. A1 - Janiak, C. A1 - Schmidt, B. M. T1 - Synthesis and Characterization of a Crystalline Imine-Based Covalent Organic Framework with Triazine Node and Biphenyl Linker and Its Fluorinated Derivate for CO2/CH4 Separation N2 - A catalyst-free Schiff base reaction was applied to synthesize two imine-linked covalent organic frameworks (COFs). The condensation reaction of 1,3,5-tris-(4-aminophenyl)triazine (TAPT) with 4,4′-biphenyldicarboxaldehyde led to the structure of HHU-COF-1 (HHU = Heinrich-Heine University). The fluorinated analog HHU-COF-2 was obtained with 2,2′,3,3′,5,5′,6,6′-octafluoro-4,4′-biphenyldicarboxaldehyde. Solid-state NMR, infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis confirmed the successful formation of the two network structures. The crystalline materials are characterized by high Brunauer–Emmett–Teller surface areas of 2352 m2/g for HHU-COF-1 and 1356 m2/g for HHU-COF-2. The products of a larger-scale synthesis were applied to prepare mixed-matrix membranes (MMMs) with the polymer Matrimid. CO2/CH4 permeation tests revealed a moderate increase in CO2 permeability at constant selectivity for HHU-COF-1 as a dispersed phase, whereas application of the fluorinated COF led to a CO2/CH4 selectivity increase from 42 for the pure Matrimid membrane to 51 for 8 wt% of HHU-COF-2 and a permeability increase from 6.8 to 13.0 Barrer for the 24 wt% MMM. KW - MOF KW - Filter PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547632 DO - https://doi.org/10.3390/ma15082807 SN - 1996-1944 VL - 15 IS - 8 SP - 1 EP - 18 PB - MDPI AN - OPUS4-54763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Göbel, M. A1 - Kirsch, S. A1 - Schwarze, L: A1 - Schmidt, L. A1 - Scholz, H. A1 - Haußmann, J. A1 - Klages, M. A1 - Scholta, J. A1 - Markötter, Henning A1 - Alrwashdeh, S. A1 - Manke, I. A1 - Müller, Bernd R. T1 - Transient limiting current measurements for characterization of gas diffusion layers N2 - The water management in proton exchange membrane fuel cells (PEMFC) is strongly influenced by the design of the gas diffusion layers (GDL). Limiting current measurements in small-scale cells operating at high stoichiometries are useful to determine the oxygen transport resistance. The oxygen transport resistance increases, once water condenses inside the GDL. In this study a new electrochemical method for voltage loss estimation of GDL induced oxygen transport losses are presented. This new method, referred to as “transient limiting current” (TLC), is compared with the literature method. TLC allows a direct estimation of oxygen transport resistance at an arbitrarily conditioned state. This study also presents a case study of liquid water visualization of a PEM fuel cell with varying GDLs types. With the help of quasi in-situ synchrotron X-ray computed tomography and time resolved radiography measurements we investigate appearance and distribution of liquid water inside the GDLs under limiting current conditions. KW - In-situ characterization of GDLs KW - In-situ synchrotron X-ray computed tomography KW - In-situ synchrotron X-ray radiography KW - BAMline PY - 2018 DO - https://doi.org/10.1016/j.jpowsour.2018.09.003 SN - 0378-7753 SN - 1873-2755 VL - 402 SP - 237 EP - 245 PB - Elsevier B.V. AN - OPUS4-46552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Senoner, Mathias A1 - Maaßdorf, A. A1 - Rooch, Heidemarie A1 - Österle, Werner A1 - Malcher, M. A1 - Schmidt, M. A1 - Kollmer, F. A1 - Paul, D. A1 - Hodoroaba, Vasile-Dan A1 - Rades, Steffi A1 - Unger, Wolfgang T1 - Lateral resolution of nanoscaled images delivered by surface-analytical instruments: application of the BAM-L200 certified reference material and related ISO standards N2 - The certified reference material BAM-L200, a nanoscale stripe pattern for length calibration and specification of lateral resolution, is described. BAM-L200 is prepared from a cross-sectioned epitaxially grown layer stack of AlxGa1–xAs and InxGa1–xAs on a GaAs substrate. The surface of BAM-L200 provides a flat pattern with stripe widths ranging down to 1 nm. Calibration distances, grating periods and stripe widths have been certified by TEM with traceability to the length unit. The combination of gratings, isolated narrow stripes and sharp edges of wide stripes offers plenty of options for the determination of lateral resolution, sharpness and calibration of length scale at selected settings of imaging surface-analytical instruments. The feasibility of the reference material for an analysis of the lateral resolution is demonstrated in detail by evaluation of ToF-SIMS, AES and EDX images. Other applications developed in the community are summarized, too. BAM-L200 fully supports the implementation of the revised International Standard ISO 18516 (in preparation) which is based on knowledge outlined in the Technical Report ISO/TR 19319:2013. KW - AES KW - BAM-L200 KW - CRM KW - EDX KW - Imaging KW - Lateral resolution KW - Sharpness KW - Standardisation KW - STXM KW - ToF-SIMS KW - XPEEM KW - XPS KW - Certified reference material KW - Imaging surface analysis PY - 2015 DO - https://doi.org/10.1007/s00216-014-8135-7 SN - 1618-2642 SN - 1618-2650 VL - 407 IS - 11 SP - 3211 EP - 3217 PB - Springer CY - Berlin AN - OPUS4-33033 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Henning, L. M. A1 - Müller, J. T. A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard A1 - Schmidt, J. A1 - Bekheet, M. F. A1 - Gurlo, A. A1 - Simon, U. T1 - Hierarchically porous and mechanically stable monoliths from ordered mesoporous silica and their water filtration potential N2 - Mechanically stable structures with interconnected hierarchical porosity combine the benefits of both small and large pores, such as high surface area, pore volume, and good mass transport capabilities. Hence, lightweight micro-/meso-/macroporous monoliths are prepared from ordered mesoporous silica COK-12 by means of spark plasma sintering (SPS, S-sintering) and compared to conventionally (C-) sintered monoliths. A multi-scale model is developed to fit the small angle X-ray scattering data and obtain information on the hexagonal lattice parameters, pore sizes from the macro to the micro range, as well as the dimensions of the silica population. For both sintering techniques, the overall mesoporosity, hexagonal pore ordering, and amorphous character are preserved. The monoliths' porosity (77–49%), mesopore size (6.2–5.2 nm), pore volume (0.50–0.22 g cm-3 ), and specific surface area (451–180 m2 g-1) decrease with increasing processing temperature and pressure. While the difference in porosity is enhanced, the structural parameters between the C-and S-sintered monoliths are largely converging at 900 C, except for the mesopore size and lattice parameter, whose dimensions are more extensively preserved in the S-sintered monoliths, however, coming along with larger deviations from the theoretical lattice. Their higher mechanical properties (biaxial strength up to 49 MPa, 724 MPa HV 9.807 N) at comparable porosities and ability to withstand ultrasonic treatment and dead-end filtration up to 7 bar allow S-sintered monoliths to reach a high permeance (2634 L m-2 h-1 bar-1), permeability (1.25 x 10^-14 m2), and ability to reduce the chemical oxygen demand by 90% during filtration of a surfactant-stabilized oil in water emulsion, while indicating reasonable resistance towards fouling. KW - SAXS KW - Hierarchically porous KW - Silica KW - Water filtration PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555928 DO - https://doi.org/10.1039/D2NA00368F SN - 2516-0230 SP - 1 EP - 17 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-55592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ganose, Alex M. A1 - Sahasrabuddhe, Hrushikesh A1 - Asta, Mark A1 - Beck, Kevin A1 - Biswas, Tathagata A1 - Bonkowski, Alexander A1 - Bustamante, Joana A1 - Chen, Xin A1 - Chiang, Yuan A1 - Chrzan, Daryl C. A1 - Clary, Jacob A1 - Cohen, Orion A. A1 - Ertural, Christina A1 - Gallant, Max C. A1 - George, Janine A1 - Gerits, Sophie A1 - Goodall, Rhys E. A. A1 - Guha, Rishabh D. A1 - Hautier, Geoffroy A1 - Horton, Matthew A1 - Inizan, T. J. A1 - Kaplan, Aaron D. A1 - Kingsbury, Ryan S. A1 - Kuner, Matthew C. A1 - Li, Bryant A1 - Linn, Xavier A1 - McDermott, Matthew J. A1 - Mohanakrishnan, Rohith Srinivaas A1 - Naik, Aakash A. A1 - Neaton, Jeffrey B. A1 - Parmar, Shehan M. A1 - Persson, Kristin A. A1 - Petretto, Guido A1 - Purcell, Thomas A. R. A1 - Ricci, Francesco A1 - Rich, Benjamin A1 - Riebesell, Janosh A1 - Rignanese, Gian-Marco A1 - Rosen, Andrew S. A1 - Scheffler, Matthias A1 - Schmidt, Jonathan A1 - Shen, Jimmy-Xuan A1 - Sobolev, Andrei A1 - Sundararaman, Ravishankar A1 - Tezak, Cooper A1 - Trinquet, Victor A1 - Varley, Joel B. A1 - Vigil-Fowler, Derek A1 - Wang, Duo A1 - Waroquiers, David A1 - Wen, Mingjian A1 - Yang, Han A1 - Zheng, Hui A1 - Zheng, Jiongzhi A1 - Zhu, Zhuoying A1 - Jain, Anubhav T1 - Atomate2: Modular workflows for materials science N2 - High-throughput density functional theory (DFT) calculations have become a vital element of computational materials science, enabling materials screening, property database generation, and training of “universal” machine learning models. While several software frameworks have emerged to support these computational efforts, new developments such as machine learned force fields have increased demands for more flexible and programmable workflow solutions. This manuscript introduces atomate2, a comprehensive evolution of our original atomate framework, designed to address existing limitations in computational materials research infrastructure. Key features include the support for multiple electronic structure packages and interoperability between them, along with generalizable workflows that can be written in an abstract form irrespective of the DFT package or machine learning force field used within them. Our hope is that atomate2's improved usability and extensibility can reduce technical barriers for high-throughput research workflows and facilitate the rapid adoption of emerging methods in computational material science. KW - Automation KW - Materials design KW - DFT workflows KW - Phonons KW - Thermal conductivity KW - Bonding analysis PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635759 DO - https://doi.org/10.1039/d5dd00019j SN - 2635-098X SP - 1 EP - 30 PB - Royal Society of Chemistry (RSC) CY - Cambridge AN - OPUS4-63575 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 - GEN A1 - Ganose, Alex M. A1 - Sahasrabuddhe, Hrushikesh A1 - Asta, Mark A1 - Beck, Kevin A1 - Biswas, Tathagata A1 - Bonkowski, Alexander A1 - Bustamante, Joana A1 - Chen, Xin A1 - Chiang, Yuan A1 - Chrzan, Daryl C. A1 - Clary, Jacob A1 - Cohen, Orion A. A1 - Ertural, Christina A1 - Gallant, Max C. A1 - George, Janine A1 - Gerits, Sophie A1 - Goodall, Rhys E. A. A1 - Guha, Rishabh D. A1 - Hautier, Geoffroy A1 - Horton, Matthew A1 - Inizan, T. J. A1 - Kaplan, Aaron D. A1 - Kingsbury, Ryan S. A1 - Kuner, Matthew C. A1 - Li, Bryant A1 - Linn, Xavier A1 - McDermott, Matthew J. A1 - Mohanakrishnan, Rohith Srinivaas A1 - Naik, Aakash A. A1 - Neaton, Jeffrey B. A1 - Parmar, Shehan M. A1 - Persson, Kristin A. A1 - Petretto, Guido A1 - Purcell, Thomas A. R. A1 - Ricci, Francesco A1 - Rich, Benjamin A1 - Riebesell, Janosh A1 - Rignanese, Gian-Marco A1 - Rosen, Andrew S. A1 - Scheffler, Matthias A1 - Schmidt, Jonathan A1 - Shen, Jimmy-Xuan A1 - Sobolev, Andrei A1 - Sundararaman, Ravishankar A1 - Tezak, Cooper A1 - Trinquet, Victor A1 - Varley, Joel B. A1 - Vigil-Fowler, Derek A1 - Wang, Duo A1 - Waroquiers, David A1 - Wen, Mingjian A1 - Yang, Han A1 - Zheng, Hui A1 - Zheng, Jiongzhi A1 - Zhu, Zhuoying A1 - Jain, Anubhav T1 - Correction: Atomate2: Modular workflows for materials science N2 - Correction for “Atomate2: modular workflows for materials science” by Alex M. Ganose et al., Digital Discovery, 2025, 4, 1944–1973, https://doi.org/10.1039/D5DD00019J. PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640297 DO - https://doi.org/10.1039/d5dd90036k SN - 2635-098X SP - 1 EP - 2 PB - Royal Society of Chemistry (RSC) CY - Cambridge AN - OPUS4-64029 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Raute, J. A1 - Schmidt, J. A1 - Bhadeliya, A. A1 - Rehmer, B. A1 - Olbricht, J. A1 - Jokisch, T. A1 - Biegler, M. A1 - Rethmeier, M. T1 - Investigation on seam quality and fatigue crack propagation in electron beam welded additive manufactured Inconel 939 N2 - Laser powder bed fusion of metals (PBF-LB/M) offers great potential for the production of new and spare parts for stationary gas turbines made of nickel superalloys such as Inconel 939 (IN939). In order to enable integration into existing assemblies and overcome design limitations, the additive manufacturing process chain must be expanded by suitable joining techniques. This study compares the electron beam welding of cast IN939 sheets and sheets produced additively using PBF-LB/M. The investigation focuses on the achievable seam quality with regard to geometric irregularities and internal defects in the form of liquation cracks on the microscale in the heat-affected zone. The evaluation of the welded samples shows no differences in the formation of the seam shape between the additively manufactured material and the cast material. For both materials, the highest quality category for beam-welded seams according to DIN EN ISO 13,919–1 was achieved at high welding speeds of 20 mm/s. Regardless of the manufacturing method, both materials show an increase in crack formation with increasing welding speed. However, due to its microstructure, the PBF-LB/M material exhibits significantly fewer microcracks overall. Final crack propagation tests on welded PBF-LB/M samples that were treated using HIP also show stable crack growth without sudden failure, which opens up potential for practical application. KW - Electron beam welding KW - Inconel 939 KW - PBF-LB/M KW - Liquation cracking KW - Fatigue crack propagation PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657015 DO - https://doi.org/10.1016/j.jajp.2026.100389 SN - 2666-3309 VL - 13 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-65701 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Franziska A1 - Schmidt, M. U. A1 - Greiser, Sebastian A1 - Emmerling, Franziska T1 - The challenging case of the theophylline–benzamide cocrystal N2 - Theophylline has been used as an active pharmaceutical ingredient (API) in the treatment of pulmonary diseases, but due to its low water solubility reveals very poor bioavailability. Based on its different hydrogen-bond donor and acceptor groups, theophylline is an ideal candidate for the formation of cocrystals. The crystal structure of the 1:1 benzamide cocrystal of theophylline, C7H8N4O2·-C7H7NO, was determined from synchrotron X-ray powder diffraction data. The compound crystallizes in the tetragonal space group P41 with four Independent molecules in the asymmetric unit. The molecules form a hunter’s fence packing. The crystal structure was confirmed by dispersion-corrected DFT calculations. The possibility of salt formation was excluded by the results of Raman and 1H solid-state NMR spectroscopic analyses. KW - powder diffraction KW - theophylline KW - benzamide KW - cocrystal KW - crystal structure KW - active pharmaceutical ingredient KW - dispersion-corrected density-functional theory PY - 2016 DO - https://doi.org/10.1107/S2053229616002643 SN - 2053-2296 VL - 72 IS - 3 SP - 217 EP - 224 AN - OPUS4-35621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Martin A1 - Erdt, René A1 - Gödde, M. A1 - Salg, St. A1 - Ittemann, L. T1 - Selbstentzündungsverhalten von Feststoffen: Validierung der Extrapolation von Labortests mithilfe halbtechnischer Versuche bis 1 m3 N2 - Vorgestellt wird ein 2018 gestartetes Projekt zur Überprüfung der Extrapolation von im Labormaßstab ermittelten Selbstentzündungstemperaturen auf technisch relevante Volumina. Für die Ermittlung reaktionskinetischer Daten von Feststoffschüttungen stehen eine Reihe von Untersuchungsmethoden zur Verfügung. Dies sind thermische Analysen wie z. B. die differential scanning calorimetry DSC sowie Mikrokalorimetrie zur hochgenauen Messung von Wärmeströmen, bei denen sehr geringe Probenmengen zum Einsatz kommen. In der Regel wird das Selbstentzündungsverhalten jedoch mithilfe von isoperibolen oder adiabaten Warmlagerungsversuchen beurteilt, hier liegen die Probenvolumina üblicherweise im Bereich von ca. 100 cm3 bis zu einigen Litern. Die Extrapolation über mehrere Größenordnungen auf technische Volumina birgt Unsicherheiten, da mit Zunahme des Lagervolumens veränderte Start- und Randbedingungen vorliegen können. Zudem besteht die Möglichkeit, dass bei in technischen Lagern vorherrschenden niedrigen Temperaturen Reaktionen ablaufen, die in Standard- Laborversuchen nicht erfasst werden, aber einen wesentlichen Einfluss auf das Selbstentzündungsverhalten aufweisen können. Hauptziel des Projektes ist es daher, die im Labormaßstab vorhandenen Prüfeinrichtungen durch einen Versuchsstand zur Untersuchung von Probengrößen von bis zu 1000 dm3 zu erweitern, die Eignung (oder Nichteignung) der etablierten Methoden nachzuweisen und im Labormaßstab nicht erfassbare Einflussgrößen zu ermitteln. Zudem sollen anhand der kleinskaligen Tests Entscheidungskriterien abgeleitet werden, ob eine Extrapolation nach den derzeit üblichen Methoden zulässig ist. T2 - 15. BAM-PTB-Kolloquium zur chemischen und physikalischen Sicherheitstechnik CY - Brunswick, Germany DA - 21.05.2019 KW - Selbstentzündung KW - Formalkinetische Daten KW - Halbtechnische Versuche KW - Thermoanalytische Methoden PY - 2020 SN - 0030-834X VL - 130 IS - 1 SP - 9 EP - 18 AN - OPUS4-51285 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Martin A1 - Erdt, René A1 - Gödde, M. A1 - Salg, St. T1 - Validierung der Extrapolation von Labortests mit Hilfe halbtechnischer Versuche bis 1 m3 und thermoanalytischer Methoden N2 - Zur Bestimmung der reaktionskinetischen Daten von Schüttgütern und iur Vorhersage des Selbstentzündungsverhaltens großer.Lager kommen verschiedene Analysemethoden zum Einsatz. Dabei handelt es sich .um thermische Verfahren wie die Differential-Scanning- Kalorimetrie OS(. die simultane Thermoanalyse STA sowie die Mikrokalorimetrie zur hochpräzisen Messung von Wärmeströmen. Für die oben genannten Methoden werden sehr kleine Probenmengen verwendet. In der Regel wird das Selbstentzündungsverhalten jedoch mit Hilfe von isoperibolen oder adiabatischen Warmlagerungsversuchen ermittelt: die Probenvolumina liegen hier meist im Bereich von ca. 100 cm3 bis zu mehreren Litern. Die Extrapolation auf technisch relevante Volumina birgt jedoch erhebliche Unsicherheiten. Diese Unsicherheiten zu identifizieren und zu reduzieren ist das Hauptziel eines 2018 gestarteten Forschungsprojekts. Dies soll in erster Linie durch den Aufbau eines Versuchsstandes zur Untersuchung von Probengrößen von bis zu. 1000 dm 3 geschehen. Sowohl Warmlagerungsversucl1e im Labormaßstab als auch thermoanalytische Verfahren. die mit Hilfe verschiedener Methoden ausgewertet werden. lassen, einzeln betrachtet. häufig nur bedingt zuverlässige Aussagen über das Selbstentzündungsverhalten von großen Schüttgütern zu. Es werden komplette Versuchsreihen mit allen genannten Prüfverfahren vorgestellt und Aussagen zur Anwendbarkeit der Extrapolationsmethoden diskutiert. T2 - VDI-Fachtagung "Sichere Handhabung brennbarer Stäube 2020" CY - Online meeting DA - 04.11.2020 KW - Selbstentzündung KW - Kinetische Daten KW - Halbtechnische Versuche KW - Thermoanalytische Methoden PY - 2020 SN - 978-3-18-092376-5 SP - 17 EP - 36 AN - OPUS4-52443 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Martin A1 - Gödde, M. A1 - Salg, S. A1 - Erdt, René T1 - Self-ignition Behaviour of Bulk Materials: How Reliable is the Extrapolation of Laboratory Tests? N2 - The self-ignition behaviour of bulks is usually determined with the aid of isoperibolic or adiabatic hot storage tests; the sample volumes here are typically in the range of approx. 100 cm³ to several litres. The extrapolation to technically relevant volumes holds, however, considerable uncertainties. To reduce these uncertainties, a test stand was set up that allows to investigation sample sizes of up to 1000 dm³. These allow the study of selfignition behavior closer to the conditions that prevail in practice. The suitability (or unsuitability) of the established methods (including dangerous goods classification tests) were to be demonstrated and influencing variables that cannot be measured on a laboratory scale were to be determined. In addition, various analytical methods were used for the determination of reaction kinetic data of solid bulk materials and to predict the self-ignition behaviour of large storages. These are thermal analyses such as differential scanning calorimetry DSC, simultaneous thermal analysis STA as well as microcalorimetry for highprecision measurement of heat flows. Complete test series using all mentioned test methods will be presented for crosslinked polyvinyl-pyrrolidone (PVP) and conclusions regarding the applicability of the extrapolation methods will be discussed. Hot storage tests up to semi-industrial scale and their combination with various thermoanalytical methods allow a much more precise prediction of the self-ignition behaviour of large bulks. A further promising approach to estimate their heat release rates, and hence, the risk of self-ignition under technical conditions, is the use of microcalorimetric methods. T2 - Loss Prevention 2022 CY - Prag, Czechia DA - 05.06.2022 KW - Self-ignition KW - Kinetic data KW - Semi-technical tests KW - Thermoanalytical methods PY - 2022 SN - 978-88-95608-88-4 DO - https://doi.org/10.3303/CET2290049 SN - 2283-9216 VL - 90 SP - 289 EP - 294 PB - AIDIC AN - OPUS4-55079 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Martin A1 - Erdt, René A1 - Gödde, M. A1 - Salg, S. T1 - Self-ignition Behaviour of Bulk Materials: How Reliable is the Extrapolation of Laboratory Tests? N2 - The self-ignition behaviour of bulks is usually determined with the aid of isoperibolic or adiabatic hot storage tests; the sample volumes here are typically in the range of approx. 100 cm³ to several litres. The extrapolation to technically relevant volumes holds, however, considerable uncertainties. To reduce these uncertainties, a test stand was set up that allows to investigation sample sizes of up to 1000 dm³. These allow the study of selfignition behavior closer to the conditions that prevail in practice. The suitability (or unsuitability) of the established methods (including dangerous goods classification tests) were to be demonstrated and influencing variables that cannot be measured on a laboratory scale were to be determined. In addition, various analytical methods were used for the determination of reaction kinetic data of solid bulk materials and to predict the self-ignition behaviour of large storages. These are thermal analyses such as differential scanning calorimetry DSC, simultaneous thermal analysis STA as well as microcalorimetry for highprecision measurement of heat flows. Complete test series using all mentioned test methods will be presented for crosslinked polyvinyl-pyrrolidone (PVP) and conclusions regarding the applicability of the extrapolation methods will be discussed. Hot storage tests up to semi-industrial scale and their combination with various thermoanalytical methods allow a much more precise prediction of the self-ignition behaviour of large bulks. A further promising approach to estimate their heat release rates, and hence, the risk of self-ignition under technical conditions, is the use of microcalorimetric methods. T2 - Loss Prevention 2022 CY - Prague, Czech Republic DA - 05.06.2022 KW - Self-ignition KW - Kinetic data KW - Semi-technical tests KW - Thermoanalytical methods PY - 2022 AN - OPUS4-55080 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 - Engl, T. A1 - Eberl, N. A1 - Gorse, C. A1 - Krüger, T. A1 - Schmidt, T. A1 - Plarre, Rüdiger A1 - Adler, C. A1 - Kaltenpoth, M. T1 - Ancient symbiosis confers desiccation resistance to stored grain pest beetles N2 - Microbial symbionts of insects provide a range of ecological traits to their hosts that are beneficial in the context of biotic interactions. However, little is known about insect symbiont-mediated adaptation to the abiotic environment, for example, temperature and humidity. Here, we report on an ancient clade of intracellular, bacteriome-located Bacteroidetes symbionts that are associated with grain and Wood pest beetles of the phylogenetically distant families Silvanidae and Bostrichidae. In the saw-toothed grain beetle Oryzaephilus surinamensis, we demonstrate that the symbionts affect cuticle thickness, melanization and hydrocarbon profile, enhancing desiccation resistance and thereby strongly improving fitness under dry conditions. Together with earlier observations on Symbiont contributions to cuticle biosynthesis in weevils, our findings indicate that convergent acquisitions of bacterial mutualists represented key adaptations enabling diverse pest beetle groups to survive and proliferate under the low ambient humidity that characterizes dry grain storage facilities. KW - Bacteroidetes KW - Cuticle KW - Desiccation resistance KW - Grain pest beetles KW - Symbiosis PY - 2017 DO - https://doi.org/10.1111/mec.14418 SN - 1365-294X SN - 0962-1083 VL - 27 IS - 8 SP - 2095 EP - 2108 AN - OPUS4-44013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rohn, H. A1 - Simon, Franz-Georg A1 - Schmidt, M. A1 - Giegrich, J. A1 - Oberender, C. A1 - Denz, W. A1 - Niebaum, A. ED - Ludwig, C. ED - Matasci, C. T1 - The Guideline Series VDI 4800 Resource Efficiency: An Approach for Increasing Resource Efficiency with Aim of Conservation of Natural Resources in the Industrial Sector N2 - In 2011, the Association of German Engineers (VDI) started working on a set of guidelines towards increased resource efficiency. These guidelines represent a framework that defines resource efficiency and outlines considerations for the producing industry. A special guideline for SMEs is included as well as guidelines on methodologies for evaluating resource use indicators, such as the cumulative raw material demand of products and production systems. Resource efficiency, defined here as the relationship between a specific benefit or use and the natural resources that need to be spent or consumed to attain this benefit or use. It can be evaluated by defining a function which expresses the specific benefit and quantifies the resource requirements through a set of indicators (use of raw materials, energy, water, land and ecosystem services including sinks). The results from this also depend on the system boundary parameters and the allocation rules for by-products and waste treatment options. Optimising resource use is possible at all stages of a product’s or production system’s life cycle chain (raw material extraction, production and manufacturing, use and consumption, and the end-of-life stage). VDI guidelines are widely accepted across Germany’s industrial sector and therefore represent an important means of mainstreaming resource efficiency in this target area. As well as providing a methodological framework, the guidelines describe strategies and measures towards increasing resource efficiency, and they enable industrial producers and service providers to identify potential areas of improvement. The full article presents an overview of the methodology and contents of these guidelines and discusses their impact in achieving absolute reductions in the industrial use of natural resources. KW - Resource efficiency KW - Life cycle thinking KW - Products and production systems KW - Standardization PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-426443 UR - https://www.wrforum.org/wrfpublicationspdf/boosting-resource-productivity/ SN - 978-3-9521409-7-0 SP - 125 EP - 132 PB - Paul Scherrer Institute CY - Villigen PSI, Switzerland ET - 1 AN - OPUS4-42644 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krietsch, Arne A1 - Kwangvitayanon, Yolada A1 - Schmidt, Martin A1 - Klippel, Alexander A1 - Schröder, Volkmar A1 - Scheid, M. T1 - Validation of the new ignition source 'exploding wire' for dust explosion testing in the 20-L-sphere N2 - The safety characteristics Maximum Explosion Pressure pniB, Maximum Explosion Pressure Rise (dp/dt)™* and Lower Explosion Limit LEL are determined in closed vessels such as the 20-L-sphere according to international Standards. Dust ignition is carried out using pyrotechnical igniters which are defined in the Standards. Due to various disadvantages of pyrotechnical igniters the need for alternative ignition sources arises again and again. Studies at the Federal Institute for Material Research and Testing (BAM) with ignition units which were able to generate ignition energies up to 2000 J showed that the so-called “exploding wire” or “fuse wire“ is suitable as an alternative ignition source. The paper presents further test results for the Validation of the exploding wire for the determination of Pm» and (dp/dt)mx in the 20-L-sphere. The tests were performed with a new ignition unit and improved electrodes which allowed ignition energies up to 10000 J. The paper also analyses propagation of flame and electrical arc on basis of high speed camera recordings. Turbulence measurements with a LDA System in the 20-L-sphere allowed investigation whether the activation of the ignition sources has an influence on the turbulence field generated during dust dispersion and whether the influence differs depending on the ignition source. T2 - Hazards 24 Symposium CY - Edinburgh, UK DA - 07.05.2014 KW - Dust explosion testing KW - Exploding wire KW - Explosion characteristics KW - Ignition source PY - 2014 SN - 978-0-85295-582-6 N1 - Serientitel: IChemE Symposium Series – Series title: IChemE Symposium Series VL - 159 SP - 1 EP - 7 AN - OPUS4-31145 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Martin A1 - Wu, D. A1 - Norman, F. A1 - Vanierschot, M. A1 - Verplaetsen, F. A1 - Berghmans, J. A1 - van den Bulck, E. T1 - Numerical investigation on the self-ignition behaviour of coal dust accumulations: The roles of oxygen, diluent gas and dust volume N2 - Self-ignition of coal dust deposits poses a higher risk of fires in oxygen-enriched oxy-fuel combustion systems. In this work, we develop a numerical method, using the commercial software COMSOL Multiphysics, to investigate self-ignition behaviour of coal dust accumulations with a main emphasis on the roles of oxygen, diluent gas and dust volume. A one-step 2nd-order reaction kinetic model considering both coal density and oxygen density is used to estimate reaction rate using the kinetic parameters from previously conducted hot-oven tests. This model is validated to predict the transient temperature and concentration profiles of South African coal dusts until ignition. The computed self-ignition temperatures of dust volumes show a good agreement with experimental results. In addition, it is found that the inhibiting effect of carbon dioxide is comparatively small and oxygen consumption increases dramatically after ignition. Parameter analysis shows that the heating value and kinetic parameters have a comparatively pronounced effect on self-ignition temperature. The model provides a satisfactory explanation for the dependence of self-ignition behaviour on gas atmospheres, thus helping to further understand the fire risk of self-ignition in oxy-fuel combustion systems. KW - Ignition temperature KW - Oxy-fuel combustion KW - Fire safety KW - Self-ignition KW - Numerical simulation PY - 2017 DO - https://doi.org/10.1016/j.fuel.2016.10.063 SN - 0016-2361 SP - 500 EP - 510 AN - OPUS4-37885 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kus, J. A1 - Kaufhold, S. A1 - Klosa, D. A1 - Jianwei, M. A1 - Schmidt, Martin A1 - Suhendra, Suhendra T1 - Coal fire geothermometer: Controlling the extent and temperature field of underground coal fire zones T2 - 2nd International conference on coal fire research (ICCFR2) CY - Berlin, Germany DA - 2010-05-19 KW - Coal fires KW - Coal petrography KW - Coal mineralogy PY - 2010 SN - 978-3-86012-397-3 IS - Part 2 - Geosciences SP - 75 EP - 85 AN - OPUS4-21459 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fischer, C. A1 - Wu, J. A1 - Meyer, U. A1 - Kong, B. A1 - Schmidt, Martin A1 - Wuttke, M. A1 - Drebenstedt, C. A1 - Barth, Uli A1 - Rüter, H. T1 - Eight years of successful bilateral cooperation: Milestones of sino-german research T2 - 2nd International conference on coal fire research (ICCFR2) CY - Berlin, Germany DA - 2010-05-19 KW - Underground coal fires KW - Sino-german cooperation PY - 2010 SN - 978-3-86012-397-3 IS - Introduction SP - 3 EP - 18 AN - OPUS4-21460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baytekin, H. Tarik A1 - Wirth, Thomas A1 - Gross, Thomas A1 - Sahre, Mario A1 - Unger, Wolfgang A1 - Theisen, J. A1 - Schmidt, M. T1 - Surface analytical characterization of micro-fluidic devices hot embossed in polymer wafers: Surface chemistry and wettability N2 - Recently, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) instrumentation has been used to address areas of interest within micro-fluidic devices providing full access to the surface chemistry established at the bottom of micro-channels therein. After careful calibration, information on surface chemistry as obtained by ToF-SIMS or XPS can be interpreted in terms of wettability expressed as contact angles which are then characteristic for the inner walls of micro-channels. Standard contact angle measurement is not applicable in micro-channels. The approach has been demonstrated to be successful with two different micro-fluidic devices hot embossed into high-end quality poly(methyl methacrylate) (PMMA) or Polycarbonate wafers. A pre-selected surface chemistry at micro-channel walls can be established by plasma technologies but ageing and rinsing effects have to be under control. A combination of ToF-SIMS, XPS and contact angle measurement techniques has been demonstrated to provide the required information. Finally, it is shown by ToF-SIMS and XPS analysis that in the production of micro-fluidic parts during practical processing using hot embossing technologies, material originating from cover foils will reside on the polymer wafer's surface. Moreover, residues of releasing agents as silicone oil used during processing can be detected by ToF-SIMS. Both cover foil residues and silicones are issues of trouble shooting in micro-fluidics because they will change contact angles efficiently. KW - Micro-fluidic device KW - PMMA KW - Polycarbonate KW - Plasma treatment KW - Wettability KW - ToF-SIMS KW - XPS PY - 2010 DO - https://doi.org/10.1002/sia.3149 SN - 0142-2421 SN - 1096-9918 VL - 42 IS - 8 SP - 1417 EP - 1431 PB - Wiley CY - Chichester AN - OPUS4-21712 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 - Baytekin, H.T. A1 - Wirth, Thomas A1 - Gross, Thomas A1 - Treu, Dieter A1 - Sahre, Mario A1 - Theisen, J. A1 - Schmidt, M. A1 - Unger, Wolfgang T1 - Determination of wettability of surface-modified hot-embossed polycarbonate wafers used in microfluidic device fabrication via XPS and ToF-SIMS N2 - The wettability of the surfaces inside the microchannels of a microfluidic device is an important property considering a liquid flows through them. Contact angle measurements usually applied to test the wettability of surfaces cannot be used for an analysis of microchannel walls within microfluidic devices. A workaround is the use of surface analytical methods, which are able to reach points of interest in microchannels and may provide information on the surface chemistry established there. In calibrating these methods by using flat polymer wafers, where the contact angle can be measured as usual, data measured in real microchannels can be evaluated in terms of wetting properties. Reference wafers of bisphenol-A polycarbonate, a polymeric material that is often used in fluidic microdevice fabrication, were treated under different oxygen plasma conditions. The modified surfaces were characterized by using XPS, time of flight (ToF)-SIMS and atomic force microscope (AFM). Surface chemistry and surface topography have been correlated with contact angle measurements. In addition, effects of ageing or rinsing after plasma treatment have also been investigated. KW - Oxygen plasma KW - Polycarbonate KW - XPS KW - ToF-SIMS KW - Principal component analysis PY - 2008 DO - https://doi.org/10.1002/sia.2724 SN - 0142-2421 SN - 1096-9918 VL - 40 IS - 3-4 SP - 358 EP - 363 PB - Wiley CY - Chichester AN - OPUS4-17340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krohne, Korinna A1 - Duschner, S. A1 - Störkle, D. A1 - Schmidt, M. A1 - Maskos, Michael T1 - Topologically controlled inter-polyelectrolyte complexes between molecular bottlebrushes and dendrimers N2 - The complexation of a cylindrical polyelectrolyte–brush-surfactant complex (PMMPSS–C12) and an oppositely charged generation-5 PAMAM dendrimer (G5-PAMAM) in methanol (MeOH) leads to kinetically controlled formation of interpolyelectrolyte complexes. In contrast, the complexation of the same starting materials in solvents with higher dielectric constant such as dimethylformamide (DMF) or N-methylformamide (NMF) results in the formation of topologically controlled complexes of cylindrical morphology. The composition of the complexes is analyzed by static and dynamic light scattering (SLS, DLS) in solution and atomic force microscopy (AFM) after spin-casting the complexes onto mica. The analyzed complexes seem to consist of one PMMPSS–C12 molecule and, with increasing G5-PAMAM content, of an increasing number of G5-PAMAM dendrimers. KW - Macromolecules PY - 2010 DO - https://doi.org/10.1021/ma101630h SN - 0024-9297 SN - 1520-5835 VL - 43 IS - 20 SP - 8645 EP - 8650 PB - American Chemical Society CY - Washington, DC AN - OPUS4-22447 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bender, S. A1 - Göllner, J. A1 - Heyn, Andreas A1 - Heilmaier, M. A1 - Schmidt, J. ED - Kainer, K.U. T1 - Basic examinations of pre-treatment and coating of magnesium alloys T2 - 8th International conference on magnesium alloys and their applications CY - Weimar, Germany DA - 2009-10-26 KW - Magnesium KW - Korrosion KW - Beschichtung KW - Vorbehandlung KW - Elektrochemisches Rauschen PY - 2010 SN - 978-3-527-32732-4 SP - 1323 EP - 1330 PB - Wiley-VCH AN - OPUS4-20743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasche, K. A1 - Ulm, G. A1 - Herrmann, K. A1 - Krumrey, M. A1 - Ade, G. A1 - Sümpel, J. A1 - Busch, I. A1 - Thomsen-Schmidt, P. A1 - Schädlich, S. A1 - Schindler, A. A1 - Frank, W. A1 - Procop, Mathias A1 - Beck, Uwe T1 - About the calibration of thickness standards on the nanometer scale T2 - 3rd International EUSPEN conference ; 3rd International conference. European Society for Precision Engineering and Nanotechnology ; 4th General meeting. European Society for Precision Engineering and Nanotechnology CY - Eindhoven, The Netherlands DA - 2002-05-26 PY - 2002 SN - 90-386-2883-8 SP - 1 EP - 5 CY - Eindhoven AN - OPUS4-2283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hasche, K. A1 - Herrmann, K. A1 - Thomsen-Schmidt, P. A1 - Krumrey, M. A1 - Ulm, G. A1 - Ade, G. A1 - Pohlenz, F. A1 - Stümpel, J. A1 - Busch, I. A1 - Schädlich, S. A1 - Frank, W. A1 - Hirsch, D. A1 - Schindler, A. A1 - Procop, Mathias A1 - Beck, Uwe T1 - Ein Beitrag zu kalibrierten Nanometerschichten für unterschiedliche Anwendungsbereiche N2 - Nanotechnologien werden gegenwärtig als leistungsfähige Oberflächentechniken in erheblichem Umfange industriell genutzt. Dabei spielen dünne Schichten und deren Kenndaten eine wesentliche Rolle, z.B. als Röntgenspiegel oder optische und magnetooptische Datenträger. Die Schichtdicke zählt hierbei zu den technologisch wichtigen Parametern. Abgeleitet von Anwenderinteressen, werden für die Röntgenreflektometrie (XRR bzw. GIXR), Elektronenstrahl-Mikroanalyse (EPMA) und Röntgenfluoreszenzanalyse (XRF) einerseits und die Ellipsometrie andererseits zugeschnittene Schichtdickenmaßverkörperungen (SDM) entwickelt, gefertigt und untersucht. Das Ziel ist die Bereitstellung praxistauglicher, kalibrierter SDM, im weiteren Schichtdickennormale (SDN) genannt. SDN sind Maßverkörperungen, für die der Schichtdickenwert mit einer definierten Messunsicherheit bekannt und auf ein metrologisch anerkanntes Längennormal zurückgeführt ist. Berichtet wird über die Herstellung und messtechnische Charakterisierung der beiden spezifischen Varianten von Maßverkörperungen. T2 - 47. Internationales Wissenschaftliches Kolloquium. Technische Universität Ilmenau ; Herbstkonferenz der Gesellschaft für Arbeitswissenschaft ; 6. Workshop Multimedia für Bildung und Wirtschaft CY - Ilmenau, Deutschland DA - 2002-09-23 PY - 2002 UR - http://publica.fraunhofer.de/documents/N-14872.html VL - 47 SP - 568 EP - 569 PB - Techn. Univ. CY - Ilmenau AN - OPUS4-2284 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koenders, L. A1 - Hasche, K. A1 - Ulm, G. A1 - Krumrey, M. A1 - Ade, G. A1 - Stümpel, J. A1 - Busch, I. A1 - Thomsen-Schmidt, P. A1 - Schädlich, S. A1 - Schindler, A. A1 - Frank, W. A1 - Beck, Uwe A1 - Procop, Mathias T1 - Über die metrologische Charakterisierung von Schichtdicken Standards im Nanometerbereich T2 - 12th Applied Surface Analysis Workshop ; AOFA 12 CY - --- DA - 2002-09-15 PY - 2002 AN - OPUS4-2285 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Boeck, T. A1 - Schmidt, K. A1 - Lorenz, M. A1 - Rosenfeld, A. A1 - Rudolph, Pascale A1 - Krüger, Jörg A1 - Kautek, Wolfgang ED - Gobrecht, J. T1 - Ultra-short pulse laser seeding techniques for silicon crystallite growth on amorphous substrates T2 - QUANTSOL 99 CY - Wildhaus, Switzerland DA - 1999-03-14 PY - 1999 SP - 1(?) EP - 3(?) AN - OPUS4-12041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - Richter, Heike A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Weinzierl, J. A1 - Schmidt, L.-P. A1 - Rutz, F. A1 - Koch, M. A1 - Richter, H. A1 - Hübers, H.-W. T1 - Imaging Capability of Terahertz and Millimeter-Wave Instrumentations for NDT of Polymer Materials T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - Time domain spectroscopy KW - Air coupled ultrasound KW - Pulsed THz radiation system KW - Pulse compression KW - THz imaging PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 9(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-13875 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Unger, Wolfgang A1 - Oran, Umut A1 - Senoner, Mathias A1 - Schmidt, M. T1 - Chemische Charakterisierung von mikro- und nanotechnologischen Bauteilen: Verfahrensentwicklung und Referenzmaterialien T2 - VDI/VDE-Tagung "Messtechnik für Mikro- und Nano-Engineering" CY - Erlangen, Germany DA - 2006-11-29 KW - Referenzmaterial KW - Mikrofluidik KW - Nanoanalytik PY - 2006 N1 - Serientitel: VDI-Berichte – Series title: VDI-Berichte IS - 1950 SP - 197 EP - 206 PB - VDI-Verl. CY - Düsseldorf AN - OPUS4-14110 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rabe, Torsten A1 - Kuchenbecker, Petra A1 - Schulz, Bärbel A1 - Schmidt, M. T1 - Hot Embossing: An Alternative Method to Produce Cavities in Ceramic Multilayer N2 - New applications of ceramic multilayers, for example, in biotechnology, sensor technology, and chemical micro-reaction technique, call for cavities with complex geometries. Hot embossing offers a promising, cost-effective way to generate these structures on the surfaces of green tapes or laminates. Cavities inside low-temperature co-fired ceramic multilayer were manufactured by a combination of hot embossing, lamination by a special adhesive technique, and zero shrinkage sintering. The edge and surface quality in the green state as well as the sintered multilayers with surface structures and cavities were extensively characterized by laser surface scanning, optical and ultrasound microscopy. Sintering shrinkage of hot-embossed laminates could be reduced in the x and y directions to less than 0.5%. KW - Keramische Multilayer KW - LTCC KW - Lamination KW - Heißprägen KW - Zero Shrinkage Sinterung PY - 2007 DO - https://doi.org/10.1111/j.1744-7402.2007.02117.x SN - 1546-542X SN - 1744-7402 VL - 4 IS - 1 SP - 38 EP - 46 PB - American Ceramic Soc. CY - Westerville, Ohio AN - OPUS4-16125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Sebastian A1 - Piechotta, Christian A1 - Godejohann, M. A1 - Win, Tin A1 - Nehls, Irene A1 - Mügge, C. T1 - Characterisation of commercially available linear alkylbenzenesulfonates by LC-SPE-NMR/MS (liquid chromatography-solid phase extraction-nuclear magnetic resonance spectroscopy-mass spectroscopy) N2 - Commercially available linear alkylbenzenesulfonates (LASs) are a mixture of various homologues and isomers, leading to 20 major species. In this work we investigated the commercial product by liquid chromatography-solid phase extraction-nuclear magnetic resonance spectroscopy-mass spectrometry (LC-SPE-NMR/MS). The commercial product was separated into 17 fractions by liquid chromatography (LC). After chromatographic separation, 5% of the flow was split to a mass spectrometer (MS) while 95% was send to post-column solid phase extraction cartridges for enrichment of the analytes (LC-SPE). After elution from the SPE-cartridges a NMR-spectrometer equipped with a cryo-probe was used for the characterisation of the different LASs species. For the first time H-1-1D and H-H-COSY spectra for 14 LASs species out of 20 major isomers are presented, whereas the 6 remaining species are detected as mixtures in 3 H-1-1D and H-H-COSY spectra. These data were used to correlate the chromatographic retention of the LASs isomers to the substitution pattern of the alkyl chain. KW - Linear alkylbenzenesulfonates KW - NMR KW - SPE KW - Liquid chromatography KW - Mass spectrometry KW - Surfactants PY - 2010 DO - https://doi.org/10.1016/j.talanta.2010.04.011 SN - 0039-9140 VL - 82 IS - 1 SP - 143 EP - 150 PB - Elsevier CY - Amsterdam AN - OPUS4-24004 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Fischer, C. A1 - Schmidt, Martin A1 - Meyer, U. A1 - Barth, Uli A1 - Drebenstedt, C. A1 - Wuttke, M. W. T1 - Innovative Technologien für die Erkundung, Löschung und Beobachtung von Kohlebränden - Phase B - N2 - Aufbauend auf den Erkenntnissen der Phase A, die sich auf das grundlegende Verständnis von Kohlebränden, sowie der Voraussetzung und des prinzipiellen Ablaufs der physikalischchemischen Brandprozesse konzentriert haben, erfolgte in Phase B eine Fokussierung auf Methoden zur Vermeidung von Kohlebränden, sowie der Löschung und Überwachung von Kohlebrandzonen, um einen Beitrag zur Verminderung von C02-Emissionen und zum Erhalt der nutzbaren Energieressourcen leisten zu können. Diese Arbeiten erfolgten insbesondere mit Bezug zu den „Clean Development Mechanisms“ (CDM), die im Rahmen des Kyoto-Protokolls entwickelt worden sind. Eine Zertifizierung von Löschaktivitäten im Rahmen des Kyoto-Protokolls setzt dabei eine nachvollziehbare Ermittlung der kohlebrandbezogenen C02-Emissionen und eine belastbare Abschätzung der durch die Löschung verringerten Emissionsmengen voraus. Wesentliche Arbeiten konzentrierten sich auf die Entwicklung von Verfahren, die eine solche Abschätzung gewährleisten können. Dazu wurden unterschiedliche Ansätze entwickelt und anhand der erhobenen Felddaten überprüft. Die untersuchten Ansätze konzentrierten sich dabei auf Verfahren, die eine Ermittlung des vorhandenen Kohlevolumens, die Erfassung der emittierten Gase und die durch die Kohlebrände verursachten Temperaturanomalien an der Tagesoberfläche ermöglichen. Die direkten Arbeiten zum Thema CDM wurden dabei in einem Arbeitspaket unter Federführung der BGR gebündelt. Die deutsche Initiative zur Erforschung der Kohlenbrände in der V.R. China leistete zweifelsfrei signifikante Beiträge zu den oben genannten Zielen. Durch die inventiven Ansätze im Bereich der Brandbewältigung konnte darüber hinaus auch in Teilen die ökonomischen Chancen für ein Engagement deutscher Unternehmen aufgezeigt werden. KW - Kohlebrände KW - Brandbekämpfung KW - Branderkundung PY - 2011 DO - https://doi.org/10.2314/GBV:664529690 SP - 1 EP - 39 AN - OPUS4-25013 LA - deu 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 - CONF A1 - Roland, U. A1 - Trommler, U. A1 - Hoyer, C. A1 - Pfütze, C. A1 - Plarre, Rüdiger A1 - Rabe, C. A1 - Höhlig, B. A1 - Holzer, F. A1 - Kraus, M. A1 - Schmidt, D. A1 - Kopinke, F.-D. T1 - Radio-frequency heating for pest control, decontamination and drying of timber and masonry N2 - A number of very relevant processes for protection and reconstruction of buildings can be supported by controlled heating: elimination of pests without using hazardous Chemicals, drying and decontamination of timber and many other building materials. For this purpose, radio-frequency (RF) dielectric heating is an advantageous Option because the materials and structures can be heated directly by energy absorption in the volume, homogeneously and, if required, relatively fast. Compared to microwaves, the penetration depths are usually much larger and the flexibility with respect to different materials is wider. Namely, heating can also be realized for dry materials because the dielectric loss is as not closely related to the presence of water as for microwave applications. T2 - 14th International conference on microwave and high frequency heating CY - Nottingham, UK DA - 16.09.2013 KW - Radio-frequency heating KW - Drying KW - Decontamination KW - Pest control KW - Timber KW - Masonry PY - 2013 SN - 978-0-85358-293-9 SP - 112 EP - 115 AN - OPUS4-29269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Durmaz, V. A1 - Schmidt, Sebastian A1 - Sabri, P. A1 - Piechotta, Christian A1 - Weber, M. T1 - Hands-off linear interaction energy approach to binding mode and affinity estimation of estrogens N2 - With this work we target the development of a predictictive model for the identification of small molecules which bind to the estrogen receptor alpha and, thus, may act as endocrine disruptors. We propose a combined thermodynamic approach for the estimation of preferential binding modes along with corresponding free energy differences using a linear interaction energy (LIE) ansatz. The LIE model is extended by a Monte Carlo approach for the computation of conformational entropies as recently developed by our group. Incorporating the entropy contribution substantially increased the correlation with experimental affinity values. Both squared coefficients for the fitted data as well as the more meaningful leave-one-out cross-validation of predicted energies were elevated up to rFit2 = 0.87 and qLOO2 = 0.82, respectively. All calculations have been performed on a set of 31 highly diverse ligands regarding their structural properties and affinities to the estrogen receptor alpha. Comparison of predicted ligand orientations with crystallographic data retrieved from the Protein database pdb.org revealed remarkable binding mode predictions. KW - Estrogenes KW - Modeling KW - Affinity PY - 2013 DO - https://doi.org/10.1021/ci400392p SN - 1549-9596 SN - 0095-2338 SN - 1549-960X VL - 53 IS - 10 SP - 2681 EP - 2688 CY - Washington, DC AN - OPUS4-29611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thomsen-Schmidt, P. A1 - Hasche, K. A1 - Ulm, G. A1 - Herrmann, K. A1 - Krumrey, M. A1 - Ade, G. A1 - Stümpel, J. A1 - Procop, Mathias A1 - Beck, Uwe T1 - Realisation and metrological characterisation of thickness standards below 100 nm T2 - DVG Jahrestagung 2002 CY - Magdeburg, Germany DA - 2002-06-17 PY - 2002 SP - 1 EP - 9 PB - Deutsche Vakuum-Gesellschaft CY - Kaiserslautern AN - OPUS4-1936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pallasch, Sebastian M. A1 - Bhosale, Manik A1 - Smales, Glen Jacob A1 - Schmidt, Caroline A1 - Riedel, Sibylle A1 - Zhao-Karger, Zhirong A1 - Esser, Birgit A1 - Dumele, Oliver T1 - Porous Azatruxene Covalent Organic Frameworks for Anion Insertion in Battery Cells N2 - Covalent organic frameworks (COFs) containing well-defined redox-active groups have become competitive materials for next-generation batteries. Although high potentials and rate performance can be expected, only a few examples of p-type COFs have been reported for charge storage to date with even fewer examples on the use of COFs in multivalent ion batteries. Herein, we report the synthesis of a p-type highly porous and crystalline azatruxene-based COF and its application as a positive electrode material in Li- and Mg-based batteries. When this material is used in Li-based half cells as a COF/carbon nanotube (CNT) electrode, a discharge potential of 3.9 V is obtained with discharge capacities of up to 70 mAh g−1 at a 2 C rate. In Mg batteries using a tetrakis(hexafluoroisopropyloxy)borate electrolyte, cycling proceeds with an averge discharge voltage of 2.9 V. Even at a fast current rate of 5 C, the capacity retention amounts to 84% over 1000 cycles. KW - COFs PY - 2024 DO - https://doi.org/10.1021/jacs.4c04044 VL - 146 IS - 25 SP - 17318 EP - 17324 PB - Journal of the American Chemical Society AN - OPUS4-60419 LA - eng 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 - Schmidt, Wolfram A1 - Sonebi, M. A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit T1 - Rheology modifying admixtures: The key to innovation in concrete technology - a general overview and implications for Africa N2 - Innovative admixture technology has significantly widened up the ränge of possibilities of concrete engineers. For many decades the water to cement ratio (w/c) was the major influencing factor for the performance of concrete. Due to the need to adjust a consistency, which still allowed reasonable workability, the w/c was typically significantly higher than technologically reasonable. Rheology modifying admixtures Support adjusting the concrete consistency largely independent of the w/c. It was only after the invention of the first superplasticizers that modern concrete technology significantly evolved in terms of flowability, strength, and durability, and only due to the steady evolution of the technology modern innovations, such as Self-Compacting Concrete, Ultra-High-Performance Concrete, or Engineered Cementitious Composites were made possible. Today’s superplasticizers are extremely versatile and can be adjusted to individual technologicalspecifications. However, the other side of the coin of versatility is that cementitious Systems incorporating superplasticizers have become more sensitive against environmental influences, such as the environmental temperature, which may cause unwanted effects or demand for supplementary admixture use such as stabilizing admixtures. Hence, concrete mixture composition with admixtures demands for a high level of expertise and offen there is lack of awareness about the mode of Operation of rheology modifying admixtures among concrete technologists. The paper gives a comprehensive overview about rheology modifying admixtures such as superplasticizers or stabilizing agents, and how they can be used depending upon the application in the most favourable way. Based on experiences with the sub-Saharan African concreting boundary conditions, which exhibit many challenges in terms of environmental boundary conditions and construction site logistics, conclusions are finally drawn, how admixtures can be used in the most beneficial way to improve the concrete casting Situation. KW - Rheology KW - Admixtures KW - Concrete KW - Superplasticizers KW - Polycarboxylate ether KW - Viscosity modifying agents PY - 2013 SN - 2224-3224 SN - 2225-0956 VL - 5 SP - 115 EP - 120 PB - International Institute for Conservation of Historic and Artistic Works CY - New York, NY, USA AN - OPUS4-30948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lu, Z. A1 - Haist, M. A1 - Ivanov, D. A1 - Jakob, C. A1 - Jansen, D. A1 - Leinitz, Sarah A1 - Link, J. A1 - Mechtcherine, V. A1 - Neubauer, J. A1 - Plank, J. A1 - Schmidt, Wolfram A1 - Schilde, C. A1 - Schröfl, C. A1 - Sowoidnich, T. A1 - Stephan, D. T1 - Characterization data of reference cement CEM I 42.5 R used for Priority Program DFG SPP 2005 “Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials” N2 - A thorough characterization of starting materials is the precondition for further research, especially for cement, which contains various phases and presents quite a complex material for fundamental scientific investigation. In the paper at hand, the characterization data of the reference cement CEM I 42.5 R used within the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The data were collected based on tests conducted by nine research groups involved in this cooperative program. For all data received, the mean values and the corresponding errors were calculated. The results shall be used for the ongoing research within the priority program. KW - Portland cement KW - Characterization KW - DFG SPP 2005 PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500849 DO - https://doi.org/10.1016/j.dib.2019.104699 SN - 2352-3409 VL - 27 SP - 104699 PB - Elsevier Inc. AN - OPUS4-50084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Asante, Bright A1 - Soria-Castro, M. A1 - Schmidt, Wolfram ED - Rogge, Andreas ED - Meng, Birgit T1 - Influence of aquacultural and agricultural bio-admixtures and binder components on yield stress and strength of cementitious systems N2 - Abstract: This study investigates the influence of bio-admixtures and bio-ashes from agricultural and aquaculture residues on the workability and strength of cement mortars. While bio-admixtures at low concentrations can enhance the strength, they create similar or lower yield stress as the reference. Bio ash, particularly at a 10% replacement level, maintained good strength, but higher replacements led to significant reductions in both strength and workability. These findings highlight the potential of sustainable construction materials but emphasize the need to balance performance specifications. T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building CY - Berlin, Germany DA - 16.10.2024 KW - Agricultural bio-admixture KW - Aquacultural bio-admixture KW - Binder component PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612955 SN - 978-3-9818564-7-7 SP - 46 EP - 54 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-61295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Sonebi, M. A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Meng, Birgit ED - Diouri, A. ED - Khachani, N. ED - Alami Talbi, M. ED - Ait Brahim, L. ED - Bahi, L. T1 - Rheology modifying admixtures: The key to innovation in concrete technology - a general overview and implications for Africa N2 - Innovative admixture technology has significantly widened up the ränge of possibilities of concrete engineers. For many decades the water to cement ratio (w/c) was the major influencing factor for the performance of concrete. Due to the need to adjust a consistency, which still allowed reasonable workability, the w/c was typically significantly higher than technologically reasonable. Rheology modifying admixtures Support adjusting the concrete consistency largely independent of the w/c. It was only after the invention of the first superplasticizers that modern concrete technology significantly evolved in terms of flowability, strength, and durability, and only due to the steady evolution of the technology modern innovations, such as Self-Compacting Concrete, Ultra-High-Performance Concrete, or Engineered Cementitious Composites were made possible. Today’s superplasticizers are extremely versatile and can be adjusted to individual technological specifications. However, the other side of the coin of versatility is that cementitious Systems incorporating superplasticizers have become more sensitive against environmental influences, such as the environmental temperature, which may cause unwanted effects or demand for supplementary admixture use such as stabilizing admixtures. Hence, concrete mixture composition with admixtures demands for a high level of expertise and offen there is lack of awareness about the mode of Operation of rheology modifying admixtures among concrete technologists. The paper gives a comprehensive overview about rheology modifying admixtures such as superplasticizers or stabilizing agents, and how they can be used depending upon the application in the most favourable way. Based on experiences with the sub-Saharan African concreting boundary conditions, which exhibit many challenges in terms of environmental boundary conditions and construction site logistics, conclusions are finally drawn, how admixtures can be used in the most beneficial way to improve the concrete casting Situation. T2 - CMSS 2013 - International congress on materials & structural stability - Building up sustainable materials & constructions CY - Rabat, Morocco DA - 27.11.2013 KW - Rheology KW - Superplasticizers KW - Stabilising agents PY - 2013 SN - 978-9954-32-689-3 SP - 1 EP - 6 AN - OPUS4-30040 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Govin, Alexandre A1 - Schmidt, Wolfram A1 - Bartholin, M. C. A1 - Grosseau, P. ED - Amziane, Sofiane ED - Sonebi, Mohammed ED - Charlet, Karine T1 - Effect of Guar gum derivatives combined with superplasticizers on properties of Portland cement pastes N2 - Chemical admixtures allow to create a variety of fresh and hardened state properties in cementitious materials. In the case of self-compacting concrete, plasticizers or superplasticizers are introduced with the aim to decrease the yield stress and the viscosity of the materials. However, in order to prevent segregation and bleeding, and to improve the water retention of cement-based system, stabilizing agents or viscosity agents are often introduced in addition. Among these admixtures, polysaccharides are most commonly used. The aim of this study is to provide an understanding of competitive or synergetic effects induced by the combination of hydroxypropyl guar stabilizing agents (HPG) and superplasticizers on cement pastes. Two polycarboxylate superplasticizers (PCE) exhibiting different charge densities and one HPG were studied. It was found that the combination of HPG with PCE superplasticizer strongly affects the rheological behavior of cement pastes. Despite the presence of HPG, the viscosity of the pastes strongly decreased with increasing dosage of PCE until it became close to the viscosity of a cement paste with PCE only. However, the use of HPG in combination with PCE allows maintaining a significant yield stress in the cement paste compared to PCE alone. The increase in the charge density of the PCE seemed to amplify the drop of the viscosity and to reduce the gain on the yield stress induced by HPG. The results also highlight a delay in the setting-time of the cement paste by adding HPG and PCE. The delay induced by HPG is significantly lower than that generated by PCEs. However, the combination of the both kind of admixtures leads to a slightly shorter setting-time compared to the PCE alone. T2 - Second International RILEM Conference on Bio-based Building Materials, 21-23 June 2017 CY - Clermont-Ferrand, France DA - 21.06.2017 KW - Rheology KW - Cement KW - Guar Gum KW - Polysaccharide KW - Superplasticizer PY - 2017 SN - 978-2-35158-192-6 SP - 55 EP - 61 PB - RILEM Publications S.A.R.L. CY - Paris, France AN - OPUS4-43547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bessaies-Bey, H. A1 - Khayat, K. H. A1 - Palacios, M. A1 - Schmidt, Wolfram A1 - Roussel, N. T1 - Viscosity modifying agents: Key components of advanced cement-based materials with adapted rheology N2 - Viscosity modifying agents (VMAs) are essential ingredients for the production of flowable cement-based materials. This paper presents an overview of commonly used VMAs and attempts to shed some light on the underlying physics at the origin of their mechanisms of action. The main molecular parameters of VMA controlling the rheological properties of the cement pore solution are highlighted. As the mechanisms of action of VMAs in cement-based materials are closely related to their affinity with the surface of cement particles, the adsorption of the main VMA types is discussed. The effect of VMAs on flow properties and stability of cement-based materials is presented for VMAs added without any superplasticizer, and then in systems incorporating both VMAs and superplasticizers. Finally, the effect of VMAs in enhancing concrete properties to secure adequate performance of different construction applications, and perspectives for future developments of novel cement-based materials made with VMAs are showcased. KW - Viscosity modifying agents KW - Cement KW - Stability KW - Rheology KW - Working mechanism KW - Compatibility PY - 2022 DO - https://doi.org/10.1016/j.cemconres.2021.106646 VL - 152 SP - 1 EP - 20 PB - Elsevier AN - OPUS4-58396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Carvello, J. M. F. A1 - Carvalho Fontes, W. A1 - de Azevedo, C. F. A1 - Brigolini, G. J. A1 - Schmidt, Wolfram A1 - Fiorotti Peixoto, R. A. T1 - Enhancing the eco-efficiency of concrete using engineered recycled mineral admixtures and recycled aggregates N2 - Non-conventional densely packed concrete mixtures are proposed and evaluated in this paper using engineered recycled mineral admixtures and recycled aggregates obtained from steel slag, quartz mining tailings, and quartzite mining tailings. High fines content sand-concretes containing coarser- and finer-than-cement recycled powders were designed to obtain blends with broader particle-size ranges and improved packing density. As a result, compressive strength up to 99 MPa, cement intensity up to 2.33 kg/m³/MPa, and consumption of recycled material up to 95 vol% were obtained. Compressive strengths up to 66 MPa and cement intensity up to 2.34 kg/m³/MPa were also obtained with the addition of coarse aggregates to such sand-concrete mixtures, with consumption of recycled material up to 96.5%. The results launch new insights on the role of recycled admixtures and aggregates on the mixture design of cement-based composites regarding efficiency improvement and technological performance. KW - Low-cement concrete KW - Recycled mineral admixture KW - Basic oxygen furnace slag KW - Quartzite mining tailing KW - Packing density PY - 2020 DO - https://doi.org/10.1016/j.jclepro.2020.120530 VL - 257 SP - 1 EP - 12 PB - Elsevier AN - OPUS4-58401 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 - CONF A1 - Sonebi, M. A1 - Khatib, J. A1 - Schmidt, Wolfram ED - Diouri, A. ED - Khachani, N. ED - Alami Talbi, M. ED - Ait Brahim, L. ED - Bahi, L. T1 - Influence of the type of viscosity-modifying admixtures and metakaolin on the rheology of grouts N2 - The Viscosity-modifying admixtures (VMAs) contribute to the control of the rheology of grouts and are used to enhance plastic viscosity, cohesion, stability, and resistance to bleeding of cement-based systems. This paper reports the results of an investigation on the effect of type of VMAs, namely two types of diutan gums and a welan gum and metakaolin (MTK), plus a superplasticiser, on the rheology behaviour of cement grouts. All mixes were made with polycarboxylic superplasticiser at 0.6% and 0.9%. The dosages of VMAs were 0.05%, and 0.10%, with a fixed water-to-binder ratio of 0.40. The investigated fresh properties of the grouts included the mini-slump flow, plate cohesion, and rheology parameters: namely yield value and plastic viscosity. The rheological parameters were obtained using a vane viscometer. Control grouts (with and without superplasticiser and VMA) were also tested and compared to mixes containing VMAs. The results indicated that the incorporation of MTK reduced the fluidity and increased the plate cohesion and yield stress, and plastic viscosity due to the higher surface area of MTK. The diutan gum grouts improved the grout fresh properties and rheology compared to the welan gum grouts. T2 - CMSS 2013 - International congress on materials & structural stability - Building up sustainable materials & constructions CY - Rabat, Morocco DA - 27.11.2013 KW - Viscosity modifying agent KW - Metakaolin KW - Diutan gum KW - Welan gum KW - Rheology PY - 2013 SN - 978-9954-32-689-3 SP - 1 EP - 6 AN - OPUS4-30041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Carvello, J. M. F. A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Fiorotti Peixoto, R. A. T1 - Influence of high-charge and low-charge PCE-based superplasticizers on Portland cement pastes containing particle-size designed recycled mineral admixtures N2 - Design : and use of engineered recycled mineral admixtures obtained from industrial and mineral waste are promising strategies to increase the range of materials suitable for use in cement-based composites. In this work, Portland cement-blended pastes containing mineral admixtures designed for improving particle packing were evaluated in the presence of low- and high-charge polycarboxylate-based superplasticizers. The powders were obtained from basic oxygen furnace slag, iron ore tailings, quartz mining tailings, and quartzite mining tailings. The zeta-potentials of the particles were obtained via electrophoretic mobility. The flow properties were evaluated by rheological tests performed in a Couette type rheometer. The hydration kinetics was evaluated by isothermal calorimetry and an adapted method based on the Vicat needle test. The high-charge PCE and the finer mineral admixtures produced more stable blends. Coarser mineral admixtures led to increased flowability and delayed hydration compared to finer ones. Steel slag powders presented the most significant plasticizer effects, but also the largest setting delays and segregation tendency. Quartz-rich superfines reduced the setting delays caused by the superplasticizers. In summary, both superplasticizers were effective in improving flow properties, but the high-charge PCE was effective in preventing segregation in pastes containing mineral admixtures coarser and heavier than cement. KW - Engineered recycled mineral admixtures KW - Rheology KW - PCE-Based superplasticizer KW - Steel slag KW - Mining tailing PY - 2020 DO - https://doi.org/10.1016/j.jobe.2020.101515 VL - 32 SP - 1 EP - 16 PB - Elsevier AN - OPUS4-58395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Govin, A. A1 - Schmidt, Wolfram A1 - Bartholin, M. C. A1 - Grosseau, P. ED - Amziane, Sofiane ED - Sonebi, M. T1 - Effect of Guar Gum Derivatives Combined with Superplasticizers on Properties of Portland Cement-Pastes N2 - Chemical admixtures allow to the create a variety of fresh and hardened state properties in cementitious materials. In the case of self-compacting concrete, plasticizers or superplasticizers are introduced with the aim to decrease the yield stress and the viscosity of the materials. However, in order to prevent segregation and bleeding, and to improve the water retention of cement-based system, stabilizing agents or viscosity agents are often introduced in addition. Among these admixtures, polysaccharides are most commonly used. The aim of this study is to provide an understanding of competitive or synergetic effects induced by the combination of hydroxypropyl guar stabilizing agents (HPG) and superplasticizers on cement pastes. Two polycarboxylate superplasticizers (PCE) exhibiting different charge densities and one HPG were studied. It was found that the combination of HPG with PCE superplasticizer strongly affects the rheological behavior of cement pastes. Despite the presence of HPG, the viscosity of the pastes strongly decreased with increasing dosage of PCE until it became close to the viscosity of a cement paste with PCE only. However, the use of HPG in combination with PCE allows maintaining a significant yield stress in the cement paste compared to PCE alone. The increase in the charge density of the PCE seemed to amplify the drop of the viscosity and to reduce the gain on the yield stress induced by HPG. The results also highlight a delay in the setting-time of the cement paste by adding HPG and PCE. The delay induced by HPG is significantly lower than that generated by PCEs. However, the combination of the both kind of admixtures leads to a slightly shorter setting-time compared to the PCE alone. T2 - 2nd International Conference on Bio-based Building Materials & 1st Conference on ECOlogical valorisation of GRAnular and FIbrous materials CY - Clermont-Ferrand, France DA - 21.06.2017 KW - Guar gum KW - Polysaccharides KW - Superplasticizer KW - Cement KW - Rheology PY - 2017 VL - PRO 119 SP - 55 EP - 61 PB - RILEM Publications S.A.R.L. CY - Paris AN - OPUS4-41038 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 - Meinel, M. A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten T1 - Betontechnologische Ansätze zur Erweiterung der Leistungsmerkmale von Betonpflastersteinen N2 - Die zunehmende Bebauung und Ausweitung städtischer Gebiete führt auf Grund entstehender Wärmespeichermassen zu innerstädtischen Hitzeinseln. Dieses Phänomen ist weithin als „Urban Heat Island Effect“ oder UHI bekannt. Der Einsatz von selbstkühlenden Betonpflastersteinen könnte diesem Phänomen entgegenwirken. Derartige Steine sollen Wasser speichern, wobei dieses bei erhöhten Temperaturen wieder verdunsten soll. Durch die Nutzung der Verdunstungsenthalpie ergibt sich eine Senkung der Oberflächentemperatur. Bei einer großflächigen Verwendung dieser Pflastersteine ist eine Reduzierung der Umgebungstemperatur verglichen mit normalen Bodenbelägen möglich. Durch Sieblinienoptimierung geeigneter Betone soll sich ein guter Kompromiss zwischen erforderlichen mechanischen Eigenschaften sowie guter Transporteigenschaften für Wasser bzw. Wasserdampf ergeben. Als besonders zweckmäßig erweisen sich Mischungen mit gleichen Anteilen an Fein- und Grobkorn. Ein Ansatz zur Realisierung der Wasserspeicherung im Betonpflasterstein stellt der Einsatz von Papierasche, einem Reststoff aus der Papierindustrie, dar. KW - Betonpflastersteine KW - Urban heat island effect PY - 2012 SN - 1439-7706 VL - 2 SP - 94 EP - 100 PB - ad-media-Verl. CY - Köln AN - OPUS4-27117 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bügel, Stefanie A1 - Hähnel, Malte A1 - Kunde, Tom A1 - de Sousa Amadeu, Nader A1 - Sun, Yangyang A1 - Spieß, Alex A1 - Beglau, Thi Hai Yen A1 - Schmidt, Bernd M. A1 - Janiak, Christoph T1 - Synthesis and Characterization of a Crystalline Imine-Based Covalent Organic Framework with Triazine Node and Biphenyl Linker and Its Fluorinated Derivate for CO2/CH4 Separation N2 - : A catalyst-free Schiff base reaction was applied to synthesize two imine-linked covalent organic frameworks (COFs). The condensation reaction of 1,3,5-tris-(4-aminophenyl)triazine (TAPT) with 4,40-biphenyldicarboxaldehyde led to the structure of HHU-COF-1 (HHU = Heinrich-Heine University). The fluorinated analog HHU-COF-2 was obtained with 2,20,3,30,5,50,6,60-octafluoro 4,40 -biphenyldicarboxaldehyde. Solid-state NMR, infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis confirmed the successful formation of the two network structures. The crystalline materials are characterized by high Brunauer–Emmett–Teller surface areas of 2352 m2/g for HHU-COF-1 and 1356 m2/g for HHU-COF-2. The products of a larger-scale synthesis were applied to prepare mixed-matrix membranes (MMMs) with the polymer Matrimid. CO2/CH4 permeation tests revealed a moderate increase in CO2 permeability at constant selectivity for HHU-COF-1 as a dispersed phase, whereas application of the fluorinated COF led to a CO2/CH4 selectivity increase from 42 for the pure Matrimid membrane to 51 for 8 wt% of HHU-COF-2 and a permeability increase from 6.8 to 13.0 Barrer for the 24 wt% MMM KW - Separation KW - COF KW - MMM KW - CO2 PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618625 DO - https://doi.org/10.3390/ma15082807 VL - 15 IS - 8 SP - 2807 PB - MDPI AN - OPUS4-61862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Martin A1 - Erdt, René A1 - Gödde, M. A1 - Salg, S. A1 - Ittemann, L. T1 - Selbstentzündungsverhalten von Feststoffen: Validierung der Extrapolation von Labortests mit Hilfe halbtechnischer Versuche bis 1 m³ N2 - Vorgestellt wird ein 2018 gestartetes Projekt zur Überprüfung der Extrapolation von im Labormaßstab ermittelten Selbstentzündungstemperaturen auf technisch relevante Volumina. Für die Ermittlung reaktionskinetischer Daten von Feststoffschüttungen stehen eine Reihe von Untersuchungsmethoden zur Verfügung. Dies sind thermische Analysen wie z.B. die differential scanning calorimetry DSC sowie Mikrokalorimetrie zur hochgenauen Messung von Wärmeströmen, bei denen sehr geringe Probenmengen zum Einsatz kommen. In der Regel wird das Selbstentzündungsverhalten jedoch mit Hilfe von isoperibolen oder adiabaten Warmlagerungsversuchen beurteilt, hier liegen die Probenvolumina üblicherweise im Bereich von ca. 100 cm³ bis zu einigen Litern. Die Extrapolation über mehrere Größenordnungen auf technische Volumina birgt Unsicherheiten, da mit Zunahme des Lagervolumens veränderte Start- und Randbedingungen vorliegen können. Zudem besteht die Möglichkeit, dass bei in technischen Lagern vorherrschenden niedrigen Temperaturen Reaktionen ablaufen, die in Standard- Laborversuchen nicht erfasst werden aber einen wesentlichen Einfluss auf das Selbstentzündungsverhalten aufweisen können. Hauptziel des Projektes ist es daher, die im Labormaßstab vorhandenen Prüfeinrichtungen durch einen Versuchsstand zur Untersuchung von Probengrößen von bis zu 1000 dm³ zu erweitern, die Eignung (oder Nichteignung) der etablierten Methoden nachzuweisen und im Labormaßstab nicht erfassbare Einflussgrößen zu ermitteln. Zudem sollen anhand der kleinskaligen Tests Entscheidungskriterien abgeleitet werden, ob eine Extrapolation nach den derzeit üblichen Methoden zulässig ist. T2 - 15. BAM-PTB-Kolloquium zur chemischen und physikalischen Sicherheitstechnik CY - Brunswick, Germany DA - 21.05.2019 KW - Spontanious ignition KW - Self-ignition KW - Minimum ignition temperature KW - Dust layers KW - Große Volumina KW - Explosionsschutz KW - Selbstentzündung KW - DSC PY - 2019 DO - https://doi.org/10.7795/210.20190521B SP - 1 EP - 15 PB - Physikalisch-Technische Bundesanstalt (PTB) AN - OPUS4-48939 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gili, A. A1 - Bischoff, B. A1 - Simon, U. A1 - Schmidt, Franziska A1 - Kober, D. A1 - Görke, O. A1 - Bekheet, M. A1 - Gurlo, A. T1 - Ceria-based dual-phase membranes for high-temperature Carbon dioxide separation: Effect of iron doping and pore generation with MgO template N2 - Dual-phase membranes for high-temperature carbon dioxide Separation have emerged as promising technology to mitigate anthropogenic greenhouse gases emissions, especially as a pre- and post-combustion separation technique in coal burning power plants. To implement These membranes industrially, the carbon dioxide permeability must be improved. In this study, Ce_(0.8) Sm_(0.2) O_(2-d) (SDC) and Ce_(0.8)Sm_(0.19)Fe_(0.01)O_(2-d) (FSDC) ceramic powders were used to form the skeleton in dual-Phase membranes. The use of MgO as an environmentally friendly pore generator allows control over the membrane porosity and microstructure in order to compare the effect of the membrane’s ceramic phase. The ceramic powders and the resulting membranes were characterized using ICP-OES, HSM, gravimetric analysis, SEM/EDX, and XRD, and the carbon dioxide flux density was quantified using a high-temperature membrane permeation setup. The carbon dioxide permeability slightly increases with the addition of iron in the FSDC membranes compared to the SDC membranes mainly due to the reported scavenging effect of iron with the siliceous impurities, with an additional potential contribution of an increased crystallite size due to viscous flow sintering. The increased permeability of the FSDC system and the proper microstructure control by MgO can be further extended to optimize carbon dioxide permeability in this membrane system. KW - Samarium doped ceria KW - SDC KW - FSDC KW - CO2 separation membranes KW - Scavenging effect of iron KW - Permeability PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488612 DO - https://doi.org/10.3390/membranes9090108 SN - 2077-0375 VL - 9 IS - 9 SP - 108, 1 EP - 15 PB - MDPI AN - OPUS4-48861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tötzke, C. A1 - Gaiselmann, G. A1 - Osenberg, M. A1 - Bohner, J. A1 - Arlt, Tobias A1 - Markötter, Henning A1 - Hilger, A. A1 - Wieder, F. A1 - Kupsch, Andreas A1 - Müller, Bernd R. A1 - Hentschel, Manfred P. A1 - Banhart, J. A1 - Schmidt, V. A1 - Lehnert, W. A1 - Manke, I. T1 - Three-dimensional study of compressed gas diffusion layers using synchrotron X-ray imaging N2 - We present a synchrotron X-ray tomographic study on the morphology of carbon fiber-based gas diffusion layer (GDL) material under compression. A dedicated compression device is used to provide well-defined compression conditions. A flat compression punch is employed to study the fiber geometry at different degrees of compression. Transport relevant geometrical parameters such as porosity, pore size and tortuosity distributions are calculated. The geometric properties notably change upon compression which has direct impact on transport conditions for gas and fluid flow. The availability of broad 3D paths, which are most important for the transport of liquid water from the catalyst layer through the GDL, is markedly reduced after compression. In a second experiment, we study the influence of the channel-land-pattern of the flow-field on shape and microstructure of the GDL. A flow-field compression punch is employed to reproduce the inhomogeneous compression conditions found during fuel cell assembly. While homogenously compressed underneath the land the GDL is much less and inhomogeneously compressed under the channel. The GDL material extends far into the channel volume where it can considerably influence gas and fluid flow. Loose fiber endings penetrate deeply into the channel and form obstacles for the discharge of liquid water droplets. KW - Synchrotron X-ray tomography KW - Gas diffusion layer (GDL) KW - Microstructure KW - Water transport path KW - Pore size analysis KW - Geometrical tortuosity PY - 2014 DO - https://doi.org/10.1016/j.jpowsour.2013.12.062 SN - 0378-7753 VL - 253 SP - 123 EP - 131 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-29979 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 - Tötzke, C. A1 - Gaiselmann, G. A1 - Osenberg, M. A1 - Arlt, Tobias A1 - Markötter, Henning A1 - Hilger, A. A1 - Kupsch, Andreas A1 - Müller, Bernd R. A1 - Schmidt, V. A1 - Lehnert, W. A1 - Manke, I. T1 - Influence of hydrophobic treatment on the structure of compressed gas diffusion layers N2 - Carbon fiber based felt materials are widely used as gas diffusion layer (GDL) in fuel cells. Their transport properties can be adjusted by adding hydrophobic agents such as polytetrafluoroethylene (PTFE). We present a synchrotron X-ray tomographic study on the felt material Freudenberg H2315 with different PTFE finishing. In this study, we analyze changes in microstructure and shape of GDLs at increasing degree of compression which are related to their specific PTFE load. A dedicated compression device mimicking the channel-land pattern of the flowfield is used to reproduce the inhomogeneous compression found in a fuel cell. Transport relevant geometrical parameters such as porosity, pore size distribution and geometric tortuosity are calculated and consequences for media transport discussed. PTFE finishing results in a marked change of shape of compressed GDLs: surface is smoothed and the invasion of GDL fibers into the flow field channel strongly mitigated. Furthermore, the PTFE impacts the microstructure of the compressed GDL. The number of available wide transport paths is significantly increased as compared to the untreated material. These changes improve the transport capacity liquid water through the GDL and promote the discharge of liquid water droplets from the cell. KW - Gas diffusion layer KW - Synchrotron Tomography KW - Compression KW - Hydrophobic treatment KW - Water transport PY - 2016 DO - https://doi.org/10.1016/j.jpowsour.2016.05.118 SN - 0378-7753 VL - 324 SP - 625 EP - 636 PB - Elsevier CY - Amsterdam AN - OPUS4-36918 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strüder, L. A1 - Hartmann, R. A1 - Holl, P. A1 - Ihle, S. A1 - Huth, M. A1 - Schmidt, J. A1 - Tham, Ch. A1 - Kanngießer, B. A1 - Baumann, J. A1 - Renno, A. A1 - Grenzer, J. A1 - Radtke, Martin A1 - Abboud, A. A1 - Pietsch, U. A1 - Soltau, H. T1 - High Speed, High Resolution imaging spectrometers based on pnCCDs for XRF and XRD applications N2 - For many years pnCCDs have been well known as X-ray detectors for spectroscopic imaging in many fields of science: X-Ray Fluorescence analysis (XRF), X-ray Diffraction (XRD) with light sources in large accelerator facilities as well as with laboratory light sources or with X-rays from celestial sources in X-ray astronomy. A brief introduction in GEXRF (Grazing Emission XRF) measurements with a laboratory laser produced plasma source will be given, PIXE (Particle Induced X-ray Emission) measurements and D2XRF (Double Dispersive X-Ray Fluorescence) and Slicing experiments with pnCCDs coupled to polycapillary optics performed at the BESSY synchrotron will be shown. Energy-dispersive Laue diffraction with ultra-hard X-rays for the analysis of defects in metals will conclude the overview of spectroscopic X-ray imaging measurements in the field of structure and dynamics of matter. KW - PnCCD KW - Synchrotron KW - XRF PY - 2016 DO - https://doi.org/10.1017/S1431927616001355 VL - 22 IS - S3 SP - 100 EP - 101 AN - OPUS4-38884 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kapoor, M. A1 - Overgaard Christensen, Ch. A1 - Wittrup Schmidt, J. A1 - Dalsgaard Sørensen, J. A1 - Thöns, Sebastian T1 - Decision analytic approach for the reclassification of concrete bridges by using elastic limit information from proof loading N2 - Reclassification of bridges, i.e., a change in load rating, using reliability-based methods and a direct update with proof load information has been presented by many authors. However, bridge reclassification has hardly been studied from a decision analytic perspective, i.e., with quantification of the risks and benefits of different classification choices, and the expected benefit gain from proof loading. We derive, explain and exemplify a decision analytic approach for bridge reclassification along with models for (1) elastic and ultimate capacity and their adaptation with proof load information, (2) proof load information with classification outcomes accounting for target reliabilities and, (3) utilities including socio-economic benefits from reclassification. The approach and models are exemplified with a case study based on reclassification of bridges with a low existing classification. Decision rules, for practical use by a highway authority to find the optimal classification, are identified and documented based on: (1) the measurement of the capacity at elastic limit by proof loading, (2) the bridge reclassification benefits, and, (3) the required annual reliability level. From a Value of Information analysis, it is concluded that the proof load information is highly valuable for reclassification in cases of high socio-economic benefits and high reliability requirements. KW - Proof loading KW - Structural reliability KW - Value of information KW - Decision analysis PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596845 DO - https://doi.org/10.1016/j.ress.2022.109049 SN - 0951-8320/ VL - 232 SP - 1 EP - 16 PB - Elsevier Ltd. AN - OPUS4-59684 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Birgit Angelika A1 - Ziemann, M. A A1 - Pentzien, Simone A1 - Gabsch, T. A1 - Koch, W. A1 - Krüger, Jörg T1 - Technical analysis of a Central Asian wall painting detached from a Buddhist cave temple on the northern Silk Road N2 - A great number of Central Asian wall paintings, archeological materials, architectural fragments, and textiles, as well as painting fragments on silk and paper, make up the so called Turfan Collection at the Asian Art Museum in Berlin. The largest part of the collection comes from the Kucha region, a very important cultural center in the third to ninth centuries. Between 1902 and 1914, four German expeditions traveled along the northern Silk Road. During these expeditions, wall paintings were detached from their original settings in Buddhist cave complexes. This paper reports a technical study of a wall painting, existing in eight fragments, from the Buddhist cave no. 40 (Ritterhöhle). Its original painted surface is soot blackened and largely illegible. Grünwedel, leader of the first and third expeditions, described the almost complete destruction of the rediscovered temple complex and evidence of fire damage. The aim of this case study is to identify the materials used for the wall paintings. Furthermore, soot deposits as well as materials from conservation interventions were of interest. Non-invasive analyses were preferred but a limited number of samples were taken to provide more precise information on the painting technique. By employing optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, micro X-ray fluorescence spectroscopy, X-ray diffraction analysis, and Raman spectroscopy, a layer sequence of earthen render, a ground layer made of gypsum, and a paint layer containing a variety of inorganic pigments were identified. KW - Wall paintings KW - Central Asia KW - Silk Road KW - Pigments KW - Microscopy PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357297 DO - https://doi.org/10.1179/2047058414Y.0000000152 VL - 61 IS - 2 SP - 113 EP - 122 PB - Routledge Taylor & Francis Group CY - London AN - OPUS4-35729 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 - Schmidt, Anita A1 - Örnemark, U. A1 - Golze, Manfred A1 - Henriksen, G.M. T1 - Surveys on the accreditation of providers of proficiency testing and external quality assessment schemes KW - Interlaboratory comparison KW - Proficiency testing KW - External quality assessment KW - Accreditation KW - Certification PY - 2006 DO - https://doi.org/10.1007/s00769-006-0161-5 SN - 0949-1775 SN - 1432-0517 VL - 11 IS - 8-9 SP - 379 EP - 384 PB - Springer CY - Berlin AN - OPUS4-12814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Hirya, N.N.M. A1 - Bjegovic, D. A1 - Uzoegbo, H.C. A1 - Kumaran, S.G. T1 - Cement technology in sub-Saharan Africa-practical and scientific experiences N2 - Sub-Saharan Africa is populated by more than half a billion people, and rapid urbanization is creating challenges in the areas of housing, roads, railways, power supply, dams and water pipelines — aspects of nfrastructure that are critical to the well being of the population. This situation indicates that cement and concrete will play a major role in the future construction technology in Africa, despite the fact that it does not have a long-lasting tradition over most of the continent. Although the continent is rich in natural resources for the production of mineral binder systems, many sub-Saharan African countries exhibit challenging boundary conditions, that have to be well understood in order to use cement and concrete technologies in a sustainable and reasonable way. KW - Africa KW - Cement KW - Technology transfer KW - SPIN PY - 2012 SN - 0002-7812 VL - 91 IS - 5 SP - 52 EP - 56 PB - American Ceramic Society CY - Westerville, Ohio AN - OPUS4-26075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marinescu, M.V.A. A1 - Schmidt, Wolfram A1 - Priebe, Nsesheye Susan A1 - Uzoegbo, H.C. A1 - Stipanovic Oslakovic, I. A1 - Kumaran, G.S. A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten A1 - Rogge, Andreas T1 - Recent developments and perspectives regarding the standardisation and quality surveillance of cement in the east, central and south african region N2 - The cement and concrete market in East, Central and Southern Africa is highly fragmented. The concrete industry in this area consists of multiple parties, including producers and suppliers of construction materials, formal and informal contractors, engineers and architects, unions of trades persons and workmen, governmental bodies and formal institutions of research and education. All these institutions mostly do not interact adequately, which makes building with cementitious materials susceptible to damage and failures. Completely opposed to the situation in Europe or North America, cement in Africa is often unaffordable, while manpower is cheap, which results in a questionable economisation of cement. Typically, there is not sufficient awareness of methods to sensibly reducing the cement content in concrete or replace Ordinary Portland Cement by adequate alternative materials. Research activities in this field of technology are often missing completely. Only few countries in the area, such as South Africa, are exempted from these issues. This paper presents the SPIN project, which is a joint project of a consortium of 8 African and 3 European partners within the ACP Science and Technology Programme. The project is funded by the EC and ACP Secretariat is the project body. The main objective of the current project is to strengthen the cement and concrete industry in the East and Central African regions. The project shall generate reasonable solution strategies to implement clean, safe and sustainable cement and concrete technology on the African continent, including general and specific guidelines for sensible application. Furthermore it shall be the kick-off for future projects, research activities and the world-wide expansion of a European-African network. The paper addresses special problems the cement and concrete market in Eastern, Central and Southern African countries has to face. Several options are presented in detail, which shall help overcoming the current situation. Customized solutions for the African market include rational methods for reducing the amount of cement used and the replacement of Ordinary Portland Cement with cheaper alternatives. The use of recycled concrete through a new and economically effective method, as well as the opportunity of using locally available resources is also discussed. T2 - 13th International congress on the chemistry of cement CY - Madrid, Spain DA - 03.07.2011 KW - Africa KW - Clean and safe cement production KW - Scientific network PY - 2011 SN - 978-84-7292-400-0 N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S. SP - 1 EP - 6 AN - OPUS4-24041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Govin, A. A1 - Bartholin, M.-C. A1 - Schmidt, Wolfram A1 - Grosseau, P. T1 - Combination of superplasticizers with hydroxypropyl guar, effect on cement-paste properties N2 - Viscosity-modifying agent (VMA) are used in several applications of concrete, such as underwater concrete, Self-Compacting Concrete (SCC) or Self-Levelling Underlayments (SLU) in order to improve the washout resistance and the stability. The study focuses on the modifications of cement pastes properties implied when a VMA (hydroxypropyl guars or HPG) and a superplasticizer are introduced together. For reaching this objective, two chemically different polycarboxylate-based superplasticizers (PCE) and two HPGs exhibiting different molar substitution ratios (MSHP), were studied. A method, combining total organic carbon and size exclusion chromatography, was developed in order to quantify the adsorption of the both admixtures. The adsorption of HPGs appears being significantly lowered by the presence of PCE, while only the adsorption of the less charged PCE is slightly affected by the HPG. As consequence, strong modifications of the rheological properties of cement pastes were noticed when HPG and PCE are combined. The desorption of HPG leads to higher yield stress and residual viscosity than with PCE alone. KW - Pore solution KW - Admixture KW - Rheology KW - Adsorption KW - Polymers PY - 2019 DO - https://doi.org/10.1016/j.conbuildmat.2019.04.137 VL - 215 SP - 595 EP - 604 PB - Elsevier Ltd. AN - OPUS4-49298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kumaran, G.S. A1 - Priebe, Nsesheye Susan A1 - Schmidt, Wolfram A1 - Florea, M.V.A. A1 - Nibasumba, P. ED - Uzoegbo, H.C. ED - Schmidt, Wolfram T1 - A study on sustainable energy for cement industries in Rwanda N2 - Rwanda is a landlocked country in the East Africa. It is surrounded by Uganda, Tanzania, Congo and Burundi. Rwanda is a fast developing country and it spends most of its revenues to import fossil fuels from either through Mombasa Port in Kenya or Dar es Salaam port in Tanzania because the energy production in Rwanda is not sufficient for its development. Transporting the fuels from these ports, add on to the cost of all materials, cement industry being no exception. There are three cement companies in Rwanda. The cement industries could not run in full production due to the shortage of fuel. Moreover, Rwanda is importing all the construction materials such as steel, roofing materials, etc from its neighbouring countries. This increases the cost of construction and the common man find difficult to own a house. In order to sustain the energy needs of Rwanda, different sources of energies should be focused. They are Peat, Geothermal, Methane gas, solar, wind, waste materials and Municipal wastes. Without affecting the environment, there is an urgent need to find a solution on sustainable energy in Rwanda. This paper discusses about the possible sources of energy in Rwanda which will improve the energy sustainability and turn the economy of Rwanda. T2 - ACCTA - International conference on advances in cement and concrete technology in Africa 2013 CY - Johannesburg, South Africa DA - 28.01.2013 KW - Biomass KW - Cement production KW - Peat KW - Energy sustainability PY - 2013 SN - 978-3-9815360-3-4 N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S. SP - 1169 EP - 1175 AN - OPUS4-27766 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Priebe, Nsesheye Susan A1 - Schmidt, Wolfram A1 - Gluth, Gregor A1 - Florea, M.V.A. A1 - Kumaran, G.S. A1 - Akindahunsi, A. A. A1 - Uzoegbo, H.C. A1 - Oslakovic, I.S. ED - Alexander, M. G. ED - Beushausen, H.-D. ED - Dehn, F. ED - Moyo, P. T1 - Concrete knowledge improvement in sub-Saharan Africa N2 - The building situation in Africa is overwhelmed with high-priced materials and lack of adequate concrete technology, which provides a challenge in the concrete industry. Worldwide, cement and concrete experts are at the cutting-edge to sustainable, green and healthy but nonetheless high-performance concrete, which is more sustainable and safer than traditional methods of construction with clay and wood. Since concrete in Africa is rather a new construction material, this sustainability experience can offer the continent a unique opportunity to begin a constantly growing building sector with the newest state-of-the-art technology. This can be achieved without subordinating to existing standards by establishing a sustainable “African concrete technology”. The major challenge for most sub-Saharan countries is the deficiency of experts, which would be required to establish such state-of-the-art technology. Based on the examples of two African-European scientific networks—SPIN and LightSHIP—this paper presents possible solution strategies for the establishment of a scientific cooperation between Europe and Africa, with links to policy making bodies that can help accelerate the progress of cement and concrete industries in Africa. T2 - 3rd International conference on concrete repair, rehabilitation and retrofitting III CY - Cape Town, South Africa DA - 03.09.2012 KW - Education KW - Research sub-Sahara KW - Africa KW - Cement KW - Concrete PY - 2012 SN - 978-0-415-89952-9 N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S. IS - Theme 5 SP - 1459 EP - 1465 PB - CRC Press CY - London, UK AN - OPUS4-26508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zemke, F. A1 - Schölch, V. A1 - Bekheet, M.F. A1 - Schmidt, Franziska T1 - Surfactant-assisted sol–gel synthesis of mesoporous bioactive glass microspheres N2 - Spherical mesoporous bioactive glasses in the silicon dioxide (SiO2)-phosphorus pentoxide (P2O5)–calcium oxide (CaO) system with a high specific surface area of up to 300m2/g and a medium pore radius of 4 nm were synthesized by using a simple one-pot surfactant-assisted sol–gel synthesis method followed by calcination at 500–700°C. The authors were able to control the particle properties by varying synthesis parameters to achieve microscale powders with spherical morphology and a particle size of around 5–10 mm by employing one structure-directing agent. Due to a high Calcium oxide content of 33·6mol% and a phosphorus pentoxide content of 4·0mol%, the powder showed very good bioactivity up to 7 d of immersion in simulated Body fluid. The resulting microspheres are promising materials for a variety of life science applications, as further processing – for example, granulation – is unnecessary. Microspheres can be applied as materials for powder-based additive manufacturing or in stable suspensions for drug release, in bone cements or fillers. KW - bioactive KW - biomaterials KW - bone PY - 2019 DO - https://doi.org/10.1680/jnaen.18.00020 SN - 2045-9831 SN - 2045-984X VL - 8 IS - 2 SP - 126 EP - 134 PB - ICE Publishing CY - London AN - OPUS4-50148 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -