TY - JOUR A1 - Chan, George C.-Y. A1 - Hieftje, Gary M. A1 - Omenetto, Nicoló A1 - Axner, Ove A1 - Bengtson, Arne A1 - Bings, Nicolas H. A1 - Blades, Michael W. A1 - Bogaerts, Annemie A1 - Bolshov, Mikhail A. A1 - Broekaert, José A.C. A1 - Chan, WingTat A1 - Costa-Fernández, José M. A1 - Crouch, Stanley R. A1 - De Giacomo, Alessandro A1 - D’Ulivo, Alessandro A1 - Engelhard, Carsten A1 - Falk, Heinz A1 - Farnsworth, Paul B. A1 - Florek, Stefan A1 - Gamez, Gerardo A1 - Gornushkin, Igor B. A1 - Günther, Detlef A1 - Hahn, David W. A1 - Hang, Wei A1 - Hoffmann, Volker A1 - Jakubowski, Norbert A1 - Karanassios, Vassili A1 - Koppenaal, David W. A1 - Kenneth Marcus, R. A1 - Noll, Reinhard A1 - Olesik, John W. A1 - Palleschi, Vincenzo A1 - Panne, Ulrich A1 - Pisonero, Jorge A1 - Ray, Steven J. A1 - Resano, Martín A1 - Russo, Richard E. A1 - Scheeline, Alexander A1 - Smith, Benjamin W. A1 - Sturgeon, Ralph E. A1 - Todolí, José-Luis A1 - Tognoni, Elisabetta A1 - Vanhaecke, Frank A1 - Webb, Michael R. A1 - Winefordner, James D. A1 - Yang, Lu A1 - Yu, Jin A1 - Zhang, Zhanxia T1 - Landmark Publications in Analytical Atomic Spectrometry: Fundamentals and Instrumentation Development N2 - The almost-two-centuries history of spectrochemical analysis has generated a body of literature so vast that it has become nearly intractable for experts, much less for those wishing to enter the field. Authoritative, focused reviews help to address this problem but become so granular that the overall directions of the field are lost. This broader perspective can be provided partially by general overviews but then the thinking, experimental details, theoretical underpinnings and instrumental innovations of the original work must be sacrificed. In the present compilation, this dilemma is overcome by assembling the most impactful publications in the area of analytical atomic spectrometry. Each entry was proposed by at least one current expert in the field and supported by a narrative that justifies its inclusion. The entries were then assembled into a coherent sequence and returned to contributors for a round-robin review. KW - Analytical atomic spectrometry KW - Spectroscopy KW - Instrumental analysis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621588 DO - https://doi.org/10.1177/00037028241263567 SN - 1943-3530 VL - 78 SP - 1 EP - 456 PB - Sage CY - London AN - OPUS4-62158 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Dirk W. T1 - Changes in structure and chemistry of cement mortars stressed by a sodium chloride solution PY - 1984 SN - 0008-8846 VL - 14 SP - 49 EP - 56 PB - Elsevier CY - Oxford AN - OPUS4-36799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tamschick, S. A1 - Rozenblut-Kościsty, B. A1 - Ogielska, M. A1 - Lehmann, Andreas A1 - Lymberakis, P. A1 - Hoffmann, F. A1 - Lutz, I. A1 - Schneider, Rudolf A1 - Kloas, W. A1 - Stöck, M. T1 - Impaired gonadal and somatic development corroborate vulnerability differences to the synthetic estrogen ethinylestradiol among deeply diverged anuran lineages N2 - Amphibians are undergoing a global decline. One poorly investigated reason could be the pollution of aquatic habitats by endocrine disrupting compounds (EDCs). We tested the susceptibility to the synthetically stabilized estrogen 17α-ethinylestradiol (EE2) in three deeply diverged anuran species, differing in sex determination systems, types of gonadogenesis and larval ecologies. To understand whether data from the amphibian model Xenopus laevis (Pipidae) are analogous and applicable to only distantly related non-model amphibians, tadpoles of X. laevis, Hyla arborea (Hylidae) and Bufo viridis (Bufonidae) were simultaneously exposed to 50, 500 and 5000 ng/L EE2 from hatching until completion of metamorphosis, using a flow-through-system under identical experimental conditions. Comparing molecularly established genetic with histologically assessed phenotypic sex in all species, we have recently shown that EE2 provoked numerous genetic-male-to-phenotypic-female sex reversals and mixed sex individuals, confirming overall its expected feminizing effect. In the present study, we focus on the influence of EE2 on gonadal and somatic development. Anatomy and histology revealed several species-specific effects. In both non-model species, H. arborea and B. viridis, high numbers of anatomically impaired gonads were observed. In H. arborea, exposed to 5000 ng/L EE2, numerous underdeveloped gonads were detected. Whereas EE2 did not alter snout-to-vent length and body weight of X. laevis metamorphs, H. arborea showed a treatment-dependent decrease, while B. viridis exhibited an increase in body weight and snout-to-vent length. Apart from a concentration-dependent occurrence of yellowish skin color in several H. arborea, no organ-specific effects were detected. Since EE2 ubiquitously occurs in many aquatic ecosystems and affects sexual and somatic development, among EDCs, it may indeed contribute to amphibian decline. The inter-species variation in developmental EE2-effects corroborates species-specific vulnerability differences towards EDCs between deeply diverged amphibian groups KW - Endocrine disruption KW - Ethinylestradiol KW - Mass spectrometry PY - 2016 DO - https://doi.org/10.1016/j.aquatox.2016.07.001 SN - 0166-445X SN - 1879-1514 VL - 177 SP - 503 EP - 514 PB - Elsevier AN - OPUS4-37633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoferer, J. A1 - Hoffmann, L.M. A1 - Goebbels, Jürgen A1 - Last, G. A1 - Weil, W. A1 - Kasper, G. T1 - Reconstruction algorithms for the internal packing density distribution of fibrous filter media based on tomographic data N2 - Algorithms were developed to approximate the 3-dimensional internal packing density distributions of fibrous filter media at different levels of detail and complexity. Each algorithm uses certain input information derived from X-ray tomographic data of filter samples. Algorithm 1 creates a binary media structure consisting of the true (i.e. tomographically determined) void distribution plus regions of uniform packing density. The average packing density of the media is maintained constant. Algorithm 2 creates a model fibrous structure of straight fibres of equal diameter and random length positioned randomly in space, while maintaining the true (i.e. tomographically determined) fibre orientation distribution. The number and length of the fibres on average adds up to the packing density of the filter. The model fibrous structure is recreated by a stationary Poisson process of convex bodies. Algorithm 3 distributes pores of random size and location within a homogeneous matrix, such that the average packing density again coincides with the true (i.e. tomographically determined) packing density. This algorithm is also based on a stationary Poisson process of convex bodies. The capability of each algorithm to recreate the essential structural features of the media was tested against 'reality' by computing the respective overall pressure drop of the filter as well as the velocity distribution in the filter interior, and comparing with the results obtained for the 'true' packing density distribution of a sample measured by tomography. Compared to the assumption of a completely homogenous filter (which gives roughly 2 times the actual Δp), all algorithms are closer to reality. The binary algorithm deviates in Δp by a factor of 1.8; algorithm 3 comes within a factor of 1.6 of the true Δp. The best approximation is by algorithm 2 which narrows the difference in Δp to a factor of 1.4. KW - X-ray tomography KW - Fibrous filter KW - Packing density PY - 2009 SN - 1479-0602 VL - 9 IS - 2 SP - 147 EP - 154 PB - Filtration Solutions CY - Newbold, Coleorton, Coalville AN - OPUS4-22880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grüning, G. A1 - Hoffmann, W. T1 - Spannungsverteilung und Formziffer des rundgekerbten Zugstabes für die Schweißgutprüfung gemäß DIN 1913 PY - 1936 IS - 28 SP - 35 EP - 36 PB - Springer CY - Berlin AN - OPUS4-16863 LA - deu 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 - GEN A1 - Marlow, Frank A1 - Dong, W. A1 - Hoffmann, Katrin A1 - Loerke, J. ED - Schüth, F. T1 - Optically and electronically functional materials PY - 2002 SN - 3-527-30246-8 SP - 3029 EP - 3063 PB - Wiley-VCH CY - Weinheim AN - OPUS4-1751 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Becker, Ben A1 - Mair, Georg W. A1 - Schoppa, Andre A1 - Duffner, Eric A1 - Szczepaniak, Mariusz A1 - Klauke, Andre A1 - Lenz, Stefan A1 - Lehr, Christian A1 - Hoffmann, Martin A1 - Gregor, Christian ED - Mair, Georg W. T1 - CryoCode: Kryodruck Tanksystem und Betankung – Validierung bis zum Normierungsvorschlag N2 - Entwicklung und Validierung eines Kryodruck-Tanksystems für Wasserstoff-Fahrzeuge. Darstellung der Versuchsergebnisse und des Normierungsvorschlags. KW - Kryodruck KW - Wasserstoff KW - Druckbehälter KW - Composite KW - Normierungsvorschlag PY - 2017 SP - 1 EP - 56 AN - OPUS4-40714 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg W. A1 - Hoffmann, Martin T1 - Baumusterprüfung von Composite-Druckgefäßen - Probabilistische Betrachtung der Mindestberstdruckforderung nach Norm N2 - Die Methoden der Sicherheitsbeurteilung von Druckgefäße aus Verbundwerkstoffen werden zunehmend verfeinert, um Material und damit auch Kosten sparen zu können. So steht auch der Mindestberstdruck als eine der Basisforderungen in den relevanten Normen in der Diskussion. Im Beitrag wird dargestellt, wie die Anforderungen nach Norm unter Berücksichtigung der realen Streuung der Festigkeitseigenschaften nach dem Kriterium einer Mindestzuverlässigkeit prinzipiell zu bewerten sind. Im Ergebnis wird abgeleitet, dass eine quantitative Reduzierung bei Beibehaltung des Charakters der Anforderung sicherheitstechnisch bedenklich ist. Der Ansatz, die Sicherheit von Composite-Druckgefäßen nach dem Kriterium eines Mindestberstdrucks anhand einzelner Prüfmustern nachzuweisen, ist weder eine notwendige noch eine hinreichende Bedingung für ein sicheres Baumuster. Das Potenzial zur Materialeinsparung kann nur durch Umstellung der Sicherheitsnachweise auf ein probabilistisches Verfahren genutzt werden. KW - Faserverbundwerkstoffe KW - Druckgefäße KW - Restfestigkeit KW - Degradation KW - Mindestberstdruck KW - Langsame Berstprüfung KW - Überlebenswahrscheinlichkeit KW - Probabilistischer Ansatz KW - Rechtsvorschriften PY - 2013 SN - 2191-0073 VL - 3 IS - 11/12 SP - 48 EP - 54 PB - Springer-VDI-Verl. CY - Düsseldorf AN - OPUS4-28909 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg W. A1 - Hoffmann, Martin A1 - Scherer, Florian A1 - Schoppa, André A1 - Szczepaniak, Mariusz T1 - Slow burst testing of samples as a method for quantification of composite cylinder degradation N2 - The current practise to focus periodic retesting of composite cylinders primarily on the hydraulic pressure test has to be evaluated as critical. The test itself always causes a certain amount of micro damage to the cylinders but does not necessarily deliver sufficient and evaluable information. Thus BAM Federal Institute of Materials Research and Testing (Germany) moves the focal point to a new approach for validation of composite cylinders, based on destructive sample tests parallel to operation. Statistical assessment of results of these destructive tests is employed for the estimation of remaining safe service life, based on reliability demands. The estimated service life is also used for the determination of re-test periods of the examined population of composite cylinders. An essential aspect of this approach is the validation of current residual strength and its prediction at any point of service life. In cases of gas cylinders with very high cycle strength, residual strength cannot be quantified statistically by means of hydraulic load cycles. As a replacement, creep tests or burst tests may be employed. BAM suggests the 'slow burst test SBT' as a combination of these two test procedures. This is a compromise between the practicability of the (conventional) burst test and the practical relevance of sustained loads during service, to be tested in creep rupture tests. In this paper, a variety of 99 burst results of a cylinder design type used for breathing apparatus (CFRP with PE-liner) is evaluated. The influence of test procedure parameters and nature and intensity of artificial ageing on the test sample strength are analysed statistically. This leads to an evaluation of different procedures of artificial ageing and the recommendation to substitute conventional burst tests by slow burst tests for the assessment of composite pressure receptacles. KW - Slow burst test KW - Sample testing KW - Residual strength KW - Scatter KW - Mean value KW - Degradation KW - Pressure rate PY - 2014 DO - https://doi.org/10.1016/j.ijhydene.2014.04.016 SN - 0360-3199 VL - 39 IS - 35 SP - 20522 EP - 20530 PB - Elsevier CY - Oxford AN - OPUS4-30732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Hoffmann, Martin A1 - Scherer, Florian T1 - Type approval of composite gas cylinders - Probabilistic analysis of rc&s concerning minimum burst pressure T2 - EHEC 2014 - European hydrogen energy conference CY - Seville, Spain DA - 2014-03-12 KW - Composite cylinders KW - Cost optimisation KW - Hydraulic cycle testing KW - Residual strength KW - Safety KW - Scatter KW - Slow burst KW - Pressure rate KW - Sustained load PY - 2014 SP - HS2-6, 242-244 AN - OPUS4-30739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg W. A1 - Scherer, Florian A1 - Hoffmann, Martin T1 - Type approval of composite gas cylinders - Probabilistic analysis of standards' requirements concerning minimum burst pressure N2 - Gas cylinders made from composite materials receive growing popularity in applications where light weight is of advantage. At the same time manufacturers are interested in cutting cost and weight through material reduction for better acceptance of a product, e.g. H2-vehicles. This requires a better understanding of safety relevant properties. The safety determination of current standards is mainly based on the minimum burst pressure of a few specimens. Various research projects were conducted aiming at reducing minimum burst pressure requirements without compromising safety. No satisfying results were found. While looking at reliability aspects it could be concluded, that the minimum burst pressure of unused specimens is not a satisfying criterion for safety during service life. This paper introduces first ideas for a method to determine one aspect of reliability of composite gas cylinders, employing probabilistic analysis of burst pressures of a sample of specimens. This can create potential for saving material cost while granting a higher safety level than the current method. Additionally, degradation over service time can be assessed. KW - Probabilistic approach KW - Regulations KW - Artificial aging KW - Slow burst test KW - Survival rate KW - Degradation trace KW - Isoasfalen PY - 2015 DO - https://doi.org/10.1016/j.ijhydene.2015.01.161 SN - 0360-3199 VL - 40 IS - 15 SP - 5359 EP - 5366 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-32697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg W. A1 - Hoffmann, Martin T1 - Assessment of the residual strength thresholds of composite pressure receptacles - Criteria for hydraulic load cycle testing N2 - Die aktuelle Praxis, die wiederkehrende Prüfung von Druckgefäßen aus Verbundwerkstoffen primär auf die hydraulische Innendruckprüfung zu begründen, ist kritisch sowohl bzgl. der Mikro-Schädigung der Prüfmuster als auch bzgl. ihrer Aussagekraft zu bewerten. Deshalb kommt durch die Bundesanstalt für Materialforschung und -prüfung BAM bei der Zulassung von Prüffristen für Composite-Druckgefäße von mehr als 5 Jahren zur Absicherung ein neuer Validierungsansatz zur Anwendung. Er ermöglicht eine Zustandsbeschreibung der Gesamtheit eines Baumusters auf der Basis wiederholt betriebsbegleitend zerstörender Prüfungen. Mit Bezug auf diesen Ansatz wird erläutert, wie die statistische Auswertung von Stichproben und deren perspektivische Extrapolation zur Vorhersage des Endes der Lebensdauer bzw. zumindest des Zeitpunkts der nächsten wiederholten Prüfung erfolgen können. Ferner wird erläutert, wie Zuverlässigkeitsgrenzwerte von der Größe von Druckgefäßen abhängig gemacht werden können und welchen Einfluss der reale Gasdruck auf die Sicherheitsbewertung im Rahmen des Ansatzes der BAM hat. Es wird insbesondere in das zentrale Arbeitsdiagramm des vorgenannten Ansatzes, das für Sicherheitsbewertungen wesentlich ist, eingeführt und erläutert, wie dieses verwendet werden kann. Hierzu wird auch ausgeführt, wie die Füllzyklenzahl und die Lastwechselfestigkeit über die neu eingeführte Größe der spezifischen Füllempfindlichkeit zusammenhängen. N2 - The current practice of periodic retesting of composite pressure receptacles primarily based on the hydraulic pressure test has to be evaluated as critical. This is justified by micro damages caused to the specimen by the test itself and by a lack of informative values. Thus, BAM Federal Institute of Materials Research and Testing uses a new validation approach in the case of retest periods of more than 5 years. It enables the description of the condition of a specific design type series based on destructive tests parallel to operation. With respect to this approach it is explained how the statistical evaluation of sample tests and their extrapolation to end of life or at least to the time of next retesting can be achieved. In addition, it is explained how the reliability limits may be linked to the size and pressure level of the respective composite pressure receptacle. The frame of this safety Approach includes the influence of the maximum working pressure on the safety assessment. One topic of this approach is the introduction of the working diagram essential for safety assessments that allows graphical evaluation of load cycle strength by mean value, scatter and survival rate of samples as well as instruction how to use it. For this, it is explained how the number of filling cycles and the reduction of the respective hydraulic residual cycle strength interacts with the newly introduced value of specific filling sensitivity. KW - Composite cylinders KW - Hydraulic cycle testing KW - Residual strength KW - Sample testing KW - Probabilis-tic PY - 2013 SN - 0025-5300 VL - 55 IS - 2 SP - 121 EP - 129 PB - Hanser CY - München AN - OPUS4-27645 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg W. A1 - Hoffmann, Martin T1 - Regulations and research on RC&S for hydrogen storage relevant to transport and vehicle issues with special focus on composite containments N2 - Developers interested in high pressure storage of hydrogen for mobile use increasingly rely on composite cylinders for onboard storage or transport of dangerous goods. Thus, composite materials and systems deserve special consideration. History gives interesting background information important to the understanding of the current situation as to regulations, codes and standards. Based on this review, origins of different regulations for the storage of hydrogen as dangerous good and as propellant for vehicles will be examined. Both categories started out using steel and sometimes aluminium as cylinder material. With composite materials becoming more common, a new problem emerged: vital input for regulations on composite pressure systems was initially derived from decades of experience with steel cylinders. As a result, both regulatory fields suffer somewhat from this common basis. Only recent developments regarding requirements for composite cylinders have begun to go more and more separate ways. Thus these differences lead to some shortcomings in regulation with respect to composite storage systems. In principle, in spite of separate development, these deficits are in both applications very much the same: there are uncertainties in the prediction of safe service life, in retesting procedures of composite cylinders and in their intervals. Hence, different aspects of uncertainties and relevant approaches to solutions will be explained. KW - Regulations KW - Hydrogen storage KW - Composite cylinders KW - Safety KW - Slow burst test KW - Cycle fatigue sensitivity PY - 2014 DO - https://doi.org/10.1016/j.ijhydene.2013.08.141 SN - 0360-3199 VL - 39 IS - 11 SP - 6132 EP - 6145 PB - Elsevier CY - Oxford AN - OPUS4-29218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Hoffmann, Martin A1 - Schönfelder, Thorsten ED - Carcassi, M.N. T1 - The slow burst testing of composite cylinders - Part I: Slow burst testing of samples as a method for quantification of cylinder degradation N2 - The current practise of focusing the periodic retesting of composite cylinders primarily on the hydraulic pressure test has to be evaluated as critical - with regard to the damage of the specimen as well as in Terms of their significance. This is justified by micro damages caused to the specimen by the test itself and by a lack of informative values. Thus BAM Federal Institute of Materials Research and Testing (Germany) uses a new approach of validation of composite for the determination of re-test periods. It enables the description of the state of a population of composite cylinders based on destructive tests parallel to operation. An essential aspect of this approach is the prediction of residual safe service life. In cases where it cannot be estimated by means of hydraulic load cycle tests, as a replacement the creep or burst test remains. As a combination of these two test procedures BAM suggests the 'slow burst test SBT'. On this a variety of about 150 burst test results on three design types of cylinders with plastic liners are presented. For this purpose both, the parameters of the test protocol as well as the nature and intensity of the pre-damage artificially aged test samples are analysed statistically. This leads first to an evaluation of the different types of artificial ageing but also to the clear recommendation that conventional burst tests be substituted totally if indented for assessment of composite pressure receptacles. T2 - ICHS2013 - 5th International conference on hydrogen safety CY - Brussels, Belgium DA - 09.09.2013 KW - Residual strength KW - CFRP KW - Gas storage KW - Reliability KW - Sample testing PY - 2013 SN - 978-2-9601366-0-9 SP - 1 EP - 12 AN - OPUS4-29260 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lindner, G.-G. A1 - Hoffmann, Katrin A1 - Witke, Klaus A1 - Reinen, D. A1 - Heinemann, Chr. A1 - Koch, W. T1 - Spectroscopic Properties of Se2 2- and Se2- in Cancrinite KW - Selen KW - Cancrinit PY - 1996 SN - 0022-4596 SN - 1095-726X VL - 126 IS - 1 SP - 50 EP - 54 PB - Elsevier CY - San Diego, Calif. AN - OPUS4-690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Wittkamp, M. A1 - Ameskamp, J. A1 - Göhde, W. A1 - Resch-Genger, Ute T1 - Luminescence lifetime encoding in time-domain flow cytometry N2 - Time-resolved flow cytometry represents an alternative to commonly applied spectral or intensity multiplexing in bioanalytics. At present, the vast majority of the reports on this topic focuses on phase-domain techniques and specific applications. In this report, we present a flow cytometry platform with time-resolved detection based on a compact setup and straightforward time-Domain measurements utilizing lifetime-encoded beads with lifetimes in the nanosecond range. We provide general assessment of time-domain flow cytometry and discuss the concept of this platform to address achievable resolution limits, data analysis, and requirements on suitable encoding dyes. Experimental data are complemented by numerical calculations on photon count numbers and impact of noise and measurement time on the obtained lifetime values. KW - Flow cytometry KW - Fluorescence KW - Life sciences KW - Lifetime encoding KW - Polymer particles PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465765 DO - https://doi.org/10.1038/s41598-018-35137-5 SN - 2045-2322 VL - 8 IS - 1 SP - 16715, 1 EP - 11 PB - Nature CY - London AN - OPUS4-46576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, R. A1 - Teich, W. A1 - Frenzel, Florian A1 - Hoffmann, Katrin A1 - Radke, J. A1 - Rösler, J. A1 - Faust, K. A1 - Blank, A. A1 - Brandenburg, S. A1 - Misch, M. A1 - Vajkoczy, P. A1 - Onken, J. S. A1 - Resch-Genger, Ute T1 - Optical characterization of sodium fluorescein in vitro and ex vivo N2 - Objective: The utilization of fluorescein-guided biopsies and resection has been recently discussed as a suitable strategy to improve and expedite operative techniques for the resection of central nervous system (CNS) tumors. However, little is known about the optical properties of sodium fluorescein (NaFl) in human tumor tissue and their potential impact on ex vivo analyses involving fluorescence-based methods. Methods: Tumor tissue was obtained from a study cohort of an observational study on the utilization of fluorescein-guided biopsy and resection (n=5). The optical properties of fluorescein-stained tissue were compared to the optical features of the dye in vitro and in control samples consisting of tumor tissue of high-grade glioma patients (n=3) without intravenous (i.v.) application of NaFl. The dye-exposed tumor tissues were used for optical measurements to confirm the detectability of NaFl emission ex vivo. The tissue samples were fixed in 4%PFA, immersed in 30% sucrose, embedded in Tissue-Tek OCT compound, and cut to 10 mm cryosections. Spatially resolved emission spectra from tumor samples were recorded on representative slides with a Confocal Laser Scanning Microscope FV1000 (Olympus GmbH, Hamburg, Germany) upon excitation with lexc = 488 nm. Results: Optical measurements of fluorescein in 0.9% sodium chloride (NaCl) under in vitro conditions showed an absorption maximum of lmax abs = 479 nm as detected with spectrophotometer Specord 200 and an emission peak at lmax em = 538 nm recorded with the emCCD detection system of a custom-made microscope-based single particle setup using a 500 nm long-pass filter. Further measurements revealed pH- and concentration-dependent emission spectra of NaFl. Under ex vivo conditions, confocal laser scanning microscopy of fluorescein tumor samples revealed a slight bathochromic shift and a broadening of the emission band. Conclusion: Tumor uptake of NaFl leads to changes in the optical properties – a bathochromic shift and broadening of the emission band – possibly caused by the dye’s high pH sensitivity and concentration-dependent reabsorption acting as an innerfilter of the dye’s emission, particularly in the short wavelength region of the Emission spectrum where absorption and fluorescence overlap. Understanding the ex vivo optical properties of fluorescein is crucial for testing and validating its further applicability as an optical probe for intravital microscopy, immunofluorescence localization studies, and flow cytometry analysis. KW - Fluorescence KW - Optical probe KW - Sensor KW - Fluorescein KW - PH KW - Imaging KW - Tissue KW - Cancer KW - Medical diagnostics KW - Tumor KW - In vivo KW - Ex vivo KW - Quantum yield KW - Dye KW - Quality assurance KW - Microscopy PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527843 DO - https://doi.org/10.3389/fonc.2021.654300 SN - 2234-943X VL - 11 SP - 1 EP - 8 PB - Frontiers Media CY - Lausanne AN - OPUS4-52784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Hoffmann, Katrin A1 - Al-Soufi, W. A1 - Resch-Genger, Ute T1 - 2,2'-Bipyridyl-3,3'-diol Incorporated into AlPO4-5 Crystals and Its Spectroscopic Properties as Related to Aqueous Liquid Media N2 - A novel fluorescent host-guest material, molecular sieves of AlPO4-5-type doped with 2,2'-bipyridyl-3,3'-diol, was prepared and spectroscopically characterized. The composite crystals show a pronounced optical anisotropy, indicating a high degree of alignment of the guest molecules within the zeolitic pore system. A mean tilting angle of 22 was found for the orientation of the individual dye molecules in the straight channels. The corrected fluorescence emission spectra were determined, and time-resolved fluorescence studies revealed that the dye molecules are preferentially found in three different types of microenvironment. By invoking pH-dependent studies of the dye in aqueous solution, we could trace these spectroscopic features back to two main influences, coadsorbed water within AlPO4-5 pores and guest-host interactions with a few relatively weak Brnsted acid (defect) sites of the inorganic host network. PY - 2002 DO - https://doi.org/10.1021/jp0259622 SN - 1520-6106 SN - 1520-5207 SN - 1089-5647 VL - 106 IS - 38 SP - 9744 EP - 9752 PB - Soc. CY - Washington, DC AN - OPUS4-1546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Resch-Genger, Ute A1 - Hoffmann, Katrin A1 - Nietfeld, W. A1 - Engel, A. A1 - Neukammer, J. A1 - Nitschke, R. A1 - Ebert, B. A1 - Macdonald, R. T1 - How to Improve Quality Assurance in Fluorometry: Fluorescence-Inherent Sources of Error and Suited Fluorescence Standards N2 - The scope of this paper is to illustrate the need for an improved quality assurance in fluorometry. For this purpose, instrumental sources of error and their influences on the reliability and comparability of fluorescence data are highlighted for frequently used photoluminescence techniques ranging from conventional macro- and microfluorometry over fluorescence microscopy and flow cytometry to microarray technology as well as in vivo fluorescence imaging. Particularly, the need for and requirements on fluorescence standards for the characterization and performance validation of fluorescence instruments, to enhance the comparability of fluorescence data, and to enable quantitative fluorescence analysis are discussed. Special emphasis is dedicated to spectral fluorescence standards and fluorescence intensity standards. KW - Fluorescence KW - Standard KW - Calibration KW - Microarray KW - In vivo imaging KW - Flow cytometry PY - 2005 DO - https://doi.org/10.1007/s10895-005-2630-3 SN - 1053-0509 SN - 1573-4994 VL - 15 IS - 3 SP - 337 EP - 362 PB - Plenum Publ. Corp. CY - New York, NY AN - OPUS4-10823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tamschick, S. A1 - Rozenblut-Kościsty, B. A1 - Ogielska, M. A1 - Lehmann, Andreas A1 - Lymberakis, P. A1 - Hoffmann, F. A1 - Lutz, I. A1 - Kloas, W. A1 - Stöck, M. T1 - Sex reversal assessments reveal different vulnerability to endocrine disruption between deeply diverged anuran lineages N2 - Multiple anthropogenic stressors cause worldwide amphibian declines. Among several poorly investigated causes is global pollution of aquatic ecosystems with endocrine disrupting compounds (EDCs). These substances interfere with the endocrine system and can affect the sexual development of vertebrates including amphibians. We test the susceptibility to an environmentally relevant contraceptive, the artificial estrogen 17α-ethinylestradiol (EE2), simultaneously in three deeply divergent systematic anuran families, a model-species, Xenopus laevis (Pipidae), and two non-models, Hyla arborea (Hylidae) and Bufo viridis (Bufonidae). Our new approach combines synchronized tadpole exposure to three EE2-concentrations (50, 500, 5,000 ng/L) in a flow-through-system and pioneers genetic and histological sexing of metamorphs in non-model anurans for EDC-studies. This novel methodology reveals striking quantitative differences in genetic-male-to-phenotypic-female sex reversal in non-model vs. model species. Our findings qualify molecular sexing in EDC-analyses as requirement to identify sex reversals and state-of-the-art approaches as mandatory to detect speciesspecific vulnerabilities to EDCs in amphibians. KW - Endocrine disruption KW - 17α-ethinylestradiol (EE2) KW - Mass spectrometry KW - Sex reversal PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357797 DO - https://doi.org/10.1038/srep23825 SN - 2045-2322 VL - 6 SP - Article No. 23825, 1 EP - 8 PB - Nature publishing group AN - OPUS4-35779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg W. A1 - Hoffmann, Martin A1 - Saul, Herbert A1 - Spode, Manfred T1 - Betrachtung von Grenzwerten der Restfestigkeit von Composite-Druckgefäßen - Teil 2: Extrapolation der Lastwechsel-Degradation N2 - Die aktuelle Praxis, auch die wiederkehrende Prüfung von Druckgefäßen aus Verbundwerkstoffen primär auf die hydraulische Innendruckprüfung abzustellen, ist sowohl im Hinblick auf die Schädigung der Prüfmuster als auch ihrer Aussagekraft kritisch zu bewerten. Daher bringt die BAM Bundesanstalt für Materialforschung und -prüfung zur Absicherung bei der Zulassung von Prüffristen für Composite-Druckgefäße, die älter als fünf Jahre sind, einen neuen Ansatz zur Anwendung. Er ermöglicht eine Zustandsbeschreibung der Population eines Baumusters auf der Basis wiederholt betriebsbegleitend zerstörender Prüfungen. Ein wesentlicher Aspekt dieses Ansatzes ist die Prognose der sicheren Restlebensdauer. Hierbei stellt der Effekt des übermäßigen Verlusts an hydraulischer Lastwechselfestigkeit im Sinne einer Degradation der Festigkeit einen kritischen Punkt in der Prognose der Sicherheit bis zum Lebensdauerende dar. KW - Faserverbundwerkstoffe KW - Druckgefäße KW - Restfestigkeit KW - Degradation KW - Stichprobenprüfung KW - Hydraulische Lastwechselprüfung KW - Lebensdauer KW - Überlebenswahrscheinlichkeit KW - Lastwechselempfindlichkeit PY - 2012 SN - 2191-0073 VL - 2 IS - 10 SP - 38 EP - 43 PB - Springer-VDI-Verl. CY - Düsseldorf AN - OPUS4-26672 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg W. A1 - Pöschko, Pascal A1 - Hoffmann, Martin A1 - Schoppa, André A1 - Spode, Manfred T1 - Betrachtung von Grenzwerten der Restfestigkeit von Composite-Druckgefäßen - Teil 1: Kriterien der hydraulischen Lastwechselprüfung N2 - Die aktuelle Praxis, auch die wiederkehrende Prüfung von Druckgefäßen aus Verbundwerkstoffen primär auf die hydraulische Innendruckprüfung abzustellen, ist sowohl bezüglich der Schädigung der Prüfmuster als auch ihrer Aussagekraft als kritisch zu bewerten. Die Bundesanstalt für Materialforschung und -prüfung BAM bringt daher bei der Zulassung von Prüffristen für Composite-Druckgefäße von mehr als fünf Jahren zur Absicherung einen neuen Ansatz zur Anwendung. Er ermöglicht eine Zustandsbeschreibung der Population eines Baumusters auf der Basis wiederholt betriebsbegleitend zerstörender Prüfungen. Nachfolgend wird erläutert, wie die statistische Auswertung von Stichproben und deren perspektivische Extrapolation erfolgen und wie Zuverlässigkeitsgrenzwerte von der Größe von Druckgefäßen abhängig gemacht werden können, sowie welchen Einfluss der reale Gasdruck auf die Sicherheitsbewertung im Rahmen des Ansatzes der BAM hat. Insbesondere wird in das zentrale Arbeitsdiagramm des Ansatzes eingeführt und erläutert, wie dieses verwendet werden kann. Hierzu wird auch ausgeführt, wie die Füllzyklenzahl und die Lastwechselfestigkeit über die neu eingeführte Größe der spezifischen Füllempfindlichkeit zusammenhängen. KW - Restfestigkeiten KW - Degradation KW - Betriebssicherheit KW - Hydraulische Lastwechselprüfung KW - Streuung KW - Ausfallwahrscheinlichkeit KW - Lastwechselempfindlichkeit PY - 2012 SN - 2191-0073 VL - 2 IS - 7/8 SP - 30 EP - 38 PB - Springer-VDI-Verl. CY - Düsseldorf AN - OPUS4-26199 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vogel, Christian A1 - Hoffmann, Marie A1 - Krüger, O. A1 - Murzin, V. A1 - Caliebe, W. A1 - Adam, Christian T1 - Chromium (VI) in phosphorus fertilizers determined with the diffusive gradients in thin-films (DGT) technique N2 - Phosphorus (P) fertilizers from secondary resources became increasingly important in the last years. However, these novel P-fertilizers can also contain toxic pollutants such as chromium in its hexavalent state (Cr(VI)). This hazardous form of chromium is therefore regulated with low limit values for agricultural products even though the correct determination of Cr(VI) in these fertilizers may be hampered by redox processes, leading to false results. Thus, we applied the novel diffusive gradients in thin-films (DGT) technique for Cr(VI) in fertilizers and compared the results with the standard wet chemical extraction method (German norm DIN EN 15192) and Cr K-edge X-ray Absorption near-edge structure (XANES) spectroscopy. We determined an overall good correlation between the wet chemical extraction and the DGT method. DGT was very sensitive and for most tested materials selective for the analysis of Cr(VI) in P-fertilizers. However, hardly soluble Cr(VI) compounds cannot be detected with the DGT method since only mobile Cr(VI) is analyzed. Furthermore, Cr K-edge XANES spectroscopy showed that the DGT binding layer also adsorbs small amounts of mobile Cr(III) so that Cr(VI) values are overestimated. Since certain types of the P fertilizers contain mobile Cr(III) or partly immobile Cr(VI), it is necessary to optimize the DGT binding layers to avoid aforementioned over- or underestimation. Furthermore, our investigations showed that the Cr K-edge XANES spectroscopy technique is unsuitable to determine small amounts of Cr(VI) in fertilizers (below approx. 1% of Cr(VI) in relation to total Cr). KW - Phosphorus fertilizer KW - Sewage sludge ash KW - Diffusive Gradients in thin films (DGT) KW - Chemical extraction KW - XANES spectroscopy PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509578 DO - https://doi.org/10.1007/s11356-020-08761-w SN - 0944-1344 VL - 27 SP - 24320 EP - 24328 PB - Springer AN - OPUS4-50957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gonzales-Gago, C. A1 - Smid, P. A1 - Hofmann, T. A1 - Venzago, C. A1 - Hoffmann, V. A1 - Gruner, W. A1 - Pfeifer, Jens A1 - Richter, Silke A1 - Kipphardt, Heinrich T1 - Investigations of matrix independent calibration approaches in fast flow glow discharge mass spectrometry N2 - The performance of glow discharge mass spectrometry (GD-MS) is investigated for the accurate quantification of metallic impurities and oxygen in solid samples using the fast flow source GD-MS instrument ELEMENT GD. Different quantification approaches based on relative and absolute sensitivity factors are evaluated for the determination of metallic impurities using three sample matrixes (Al, Cu and Zn). The effect of the discharge conditions (voltage, current, discharge gas pressure/flow) on the sensitivity is investigated and the parameters are optimized to favour matrix independent calibrations. Improved standard relative sensitivity factors (StdRSFs) are calculated under optimal conditions based on multi-matrix calibrations. The sputtering rate corrected calibration is also presented as a multi-matrix calibration approach. The capabilities of GD-MS for oxygen determination are also investigated using a set of new conductive samples containing oxygen with mass fractions in the percent range in three different matrices (Al, Mg and Cu) produced by a sintering process. Poor limits of detection (in the order of g/kg) were obtained as consequence of the reduced sensitivity of oxygen in GD-MS and high oxygen background signal intensity as well as its variations. The absolute sensitivity procedure is shown as a matrix-independent approach, which provides quantitative values consistent with those obtained by carrier gas hot extraction (CGHE). KW - Fast flow GD KW - GDMS KW - Calibration KW - Matrix independent calibration PY - 2019 DO - https://doi.org/10.1039/c9ja00023b SN - 1364-5544 SN - 0267-9477 VL - 34 IS - 6 SP - 1109 EP - 1125 PB - Royal Society of Chemistry CY - London AN - OPUS4-47842 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Klemm, D. A1 - Reinholz, Uwe A1 - Strub, E. A1 - Röhrich, J. A1 - Bohne, W. A1 - Hoffmann, V. A1 - Wetzig, K. T1 - Potential candidates of certified reference material for determination of hydrogen concentration with glow discharge optical emission spectrometry (GD-OES) - a feasibility study N2 - Three different coatings/layers have been found in a feasibility study as potential candidates for certified reference materials for the determination of hydrogen concentration by GD-OES: (i) electroplated zinc, (ii) carbon-rich coatings and (iii) amorphous silicon layers. KW - CRM KW - Hydrogen KW - GDS PY - 2008 DO - https://doi.org/10.1039/b717924c SN - 0267-9477 SN - 1364-5544 VL - 23 SP - 460 EP - 462 PB - Royal Society of Chemistry CY - London AN - OPUS4-17335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wolf, S. E. A1 - Müller, L. A1 - Barrea, R. A1 - Kampf, C.J. A1 - Leiterer, Jork A1 - Panne, Ulrich A1 - Hoffmann, T. A1 - Emmerling, Franziska A1 - Tremel, W. T1 - Carbonate-coordinated metal complexes precede the formation of liquid amorphous mineral emulsions of divalent metal carbonates N2 - During the mineralisation of metal carbonates MCO3 (M = Ca, Sr, Ba, Mn, Cd, Pb) liquid-like amorphous intermediates emerge. These intermediates that form via a liquid/liquid phase separation behave like a classical emulsion and are stabilized electrostatically. The occurrence of these intermediates is attributed to the formation of highly hydrated networks whose stability is mainly based on weak interactions and the variability of the metal-containing pre-critical clusters. Their existence and compositional freedom are evidenced by electrospray ionization mass spectrometry (ESI-MS). Liquid intermediates in non-classical crystallisation pathways seem to be more common than assumed. PY - 2011 DO - https://doi.org/10.1039/c0nr00761g SN - 2040-3364 SN - 2040-3372 IS - 3 SP - 1158 EP - 1165 PB - RSC Publ. CY - Cambridge AN - OPUS4-23355 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Martin A1 - Gregor, Christian A1 - Schulz, Michael A1 - Szczepaniak, Mariusz A1 - Mair, Georg W. T1 - Entwickelt und validiert - Probengeometrie zur Untersuchung von gewickelten Faserverbundproben N2 - Durch die beschriebene, auf eine Umfangsbelastung ausgelegte Probengeometrie werden Fertigung und Einsatz von Druckbehältern nachempfunden. Dafür wurden bereits bestehende Probenformen überarbeitet, um im Probenkörper eine unidirektionale Zugbelastung zu erzeugen. Da die endgültigen Eigenschaften von faserverstärktem Kunststoff erst in der Fertigung entstehen, sind gleiche Fertigungsbedingungen von Proben und Bauteilen wichtig. Die hier vorgestellte Probe verspricht dadurch eine gute Eignung für den Einsatz bei Untersuchungen zum Zeitstandsverhalten. KW - Faserverstärkte Kunststoffe (FVK) KW - Druckbehälter KW - Zeitstand KW - Zugprobe PY - 2012 SN - 1865-4819 VL - 5 SP - 44 EP - 49 PB - Springer Vieweg, Springer Fachmedien Wiesbaden GmbH CY - Wiesbaden AN - OPUS4-26893 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Grotheer, E. A1 - Vogel, Christian A1 - Kolomiets, O. A1 - Hoffmann, U. A1 - Unger, M. A1 - Siesler, H.W. ED - Salzer, R. ED - Siesler, H.W. T1 - FT-IR and NIR spectroscopic imaging: principles, practical aspects, and applications in material and pharmaceutical science PY - 2014 SN - 978-3-527-33652-4 SN - 978-3-527-67816-7 SN - 978-3-527-67815-0 SN - 978-3-527-67814-3 SN - 978-3-527-67813-6 SP - Chapter 8, 341 EP - 396 PB - Wiley-VCH Verlag GmbH & Co. KGaA ET - 2nd Edition AN - OPUS4-31432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Braun, Ulrike A1 - Schartel, Bernhard ED - Schartel, Bernhard T1 - Flame retardant epoxy resin system for liquid composite moulding applications KW - Epoxy resin KW - Fire retardancy PY - 2007 SN - 978-3-8334-8873-3 SP - 69 EP - 84 PB - Books on Demand GmbH CY - Norderstedt AN - OPUS4-17627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Ciesielski, M. A1 - Döring, M. A1 - Braun, Ulrike A1 - Knoll, Uta A1 - Schartel, Bernhard T1 - Effective halogen-free flame retardants for carbon fibre-reinforced epoxy composites N2 - DOPO-based flame retardants with tailored chemical structures are proposed for carbon fibre reinforced epoxy composites. Critical properties related to the fracture toughness are maintained, effectively allowing the use of such compounds in composites for demanding applications. KW - Fire retardancy KW - DOPO KW - Epoxy resin KW - LOI KW - UL94 PY - 2006 DO - https://doi.org/10.1007/s10853-006-0134-4 SN - 0022-2461 SN - 1573-4803 VL - 41 IS - 15 SP - 4981 EP - 4984 PB - Springer Science + Business Media B.V. CY - New York, USA AN - OPUS4-12641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braun, Ulrike A1 - Knoll, Uta A1 - Schartel, Bernhard A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Perez-Graterol, R. A1 - Sandler, J.K.W. A1 - Altstädt, V. T1 - Novel Phosphorus-Containing Poly(ether sulfone)s and Their Blends with an Epoxy Resin: Thermal Decomposition and Fire Retardancy N2 - Summary: The decomposition of novel phosphorus-containing poly(oxyphenylene-sulfonyl-phenylene-oxy-diphenyl phenylene phosphine oxide) (PSU_I), 2,5-dihydroxy-1-biphenylene-phosphine oxide based polysulfone (PSU_II), poly(sulfonyl-diphenylphenylene phosphonate) (PSU_P) and bisphenol A-based polysulfone (PSU) is studied. The influence of the chemical structure, charring and phosphorus release is discussed based on the mass loss, kinetics and products. The pyrolysis and fire behaviour of blends with epoxy resin (EP) are studied. For EP-PSU_II, phosphorus initiates water elimination and changes the decomposition pathway of EP. The fire behaviour of EP-PSU shows some improvements, whereas the heat release rate is crucially reduced for EP-PSU_II due to simultaneous char formation and flame inhibition. KW - Epoxy KW - Flame retardance KW - High performance polymers KW - Polysulfones KW - Thermogravimetric analysis (TGA) PY - 2006 DO - https://doi.org/10.1002/macp.200600182 SN - 1022-1352 SN - 1521-3935 VL - 207 IS - 16 SP - 1501 EP - 1514 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-12650 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braun, Ulrike A1 - Balabanovich, Aliaksandr A1 - Schartel, Bernhard A1 - Knoll, Uta A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Perez, R. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. T1 - Influence of the oxidation state of phosphorus on the decomposition and fire behaviour of flame-retarded epoxy resin composites N2 - A systematic and comparative evaluation of the pyrolysis of halogen-free flame-retarded epoxy resins containing phosphine oxide, phosphinate, phosphonate, and phosphate (phosphorus contents around 2.6 wt.%) and the fire behaviour of their carbon fibre composites is presented. Decomposition pathways are proposed based on the thermal analysis (TG), TG coupled with evolved gas analysis (TG-FTIR), kinetics and analysis of the residue with FTIR and XPS. All organophosphorus-modified hardeners containing phenoxy groups lead to a reduced decomposition temperature and mass loss step for the main decomposition of the cured epoxy resin. With increasing oxidation state of the phosphorus the thermally stable residue increases, whereas the release of phosphorus-containing volatiles decreases. The flammability of the composites was investigated with LOI and UL 94 and the fire behaviour for forced-flaming conditions with cone calorimeter tests performed using different irradiations. The flame retardancy mechanisms are discussed. With increasing oxidation state of the phosphorus additional charring is observed, whereas the flame inhibition, which plays the more important role for the performance of the composites, decreases. The processing and the mechanical performance (delamination resistance, flexural properties and interlaminar bonding strength) of the fibre-reinforced composites containing phosphorus were maintained at a high level and, in some cases, even improved. The potential for optimising flame retardancy while maintaining mechanical properties is highlighted in this study. KW - Fire retardant KW - Composites KW - Organophosphorus-containing epoxy resin PY - 2006 DO - https://doi.org/10.1016/j.polymer.2006.10.022 SN - 0032-3861 SN - 1873-2291 VL - 47 IS - 26 SP - 8495 EP - 8508 PB - Springer CY - Berlin AN - OPUS4-14054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Balabanovich, Aliaksandr A1 - Schartel, Bernhard T1 - Effective halogen-free flame retardancy for a monocomponent polyfunctional epoxy using an oligomeric organophosphorus compound N2 - Oligomeric organo-phosphorus flame retardants are proposed for a monocomponent polyfunctional epoxy resin system (RTM6) without significantly deteriorating the overall performance of the resulting material. KW - DOPO KW - Epoxy resin KW - Fire retardancy KW - LOI PY - 2006 DO - https://doi.org/10.1007/s10853-006-1079-3 SN - 0022-2461 SN - 1573-4803 VL - 41 IS - 24 SP - 8347 EP - 8351 PB - Springer Science + Business Media B.V. CY - New York, USA AN - OPUS4-14112 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Ciesielski, M. A1 - Döring, M. A1 - Braun, Ulrike A1 - Balabanovich, Aliaksandr A1 - Schartel, Bernhard T1 - Novel phosphorus-modified polysulfone as a combined flame retardant and toughness modifier for epoxy resins N2 - A novel phosphorus-modified polysulfone (P-PSu) was employed as a combined toughness modifier and a source of flame retardancy for a DGEBA/DDS thermosetting system. In comparison to the results of a commercially available polysulfone (PSu), commonly used as a toughness modifier, the chemorheological changes during curing measured by means of temperature-modulated DSC revealed an earlier occurrence of mobility restrictions in the P-PSu-modified epoxy. A higher viscosity and secondary epoxy-modifier reactions induced a sooner vitrification of the reacting mixture; effects that effectively prevented any phase separation and morphology development in the resulting material during cure. Thus, only about a 20% increase in fracture toughness was observed in the epoxy modified with 20 wt.% of P-PSu, cured under standard conditions at 180 °C for 2 h. Blends of the phosphorus-modified and the standard polysulfone (PSu) were also prepared in various mixing ratios and were used to modify the same thermosetting system. Again, no evidence for phase separation of the P-PSu was found in the epoxy modified with the P-PSu/PSu blends cured under the selected experimental conditions. The particular microstructures formed upon curing these novel materials are attributed to a separation of PSu from a miscible P-PSu–epoxy mixture. Nevertheless, the blends of P-PSu/PSu were found to be effective toughness/flame retardancy enhancers owing to the simultaneous microstructure development and polymer interpenetration. KW - Flame retardants KW - Phosphorus-modified polysulfone KW - Fracture toughness PY - 2007 SN - 0032-3861 SN - 1873-2291 VL - 48 IS - 3 SP - 778 EP - 790 PB - Springer CY - Berlin AN - OPUS4-14515 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Balabanovich, Aliaksandr A1 - Braun, Ulrike A1 - Knoll, Uta A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Perez, R. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. T1 - Pyrolysis of Epoxy Resins and Fire Behavior of Epoxy Resin Composites Flame-Retarded with 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide Additives N2 - The pyrolysis of an epoxy resin and the fire behavior of corresponding carbon fiber-reinforced composites, both flame-retarded with either 10-ethyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide or 1,3,5-tris[2-(9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide-10-)ethyl]1, 3,5-triazine-2,4,6(1H,3H,5H)-trione, are investigated. The different fire retardancy mechanisms are discussed, and their influence on the fire properties assessed, in particular for flammability (limiting oxygen index, UL 94) and developing fires (cone calorimeter with different external heat fluxes of 35, 50, and 70 kW m-2). Adding the flame retardants containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide affects the fire behavior by both condensed phase and gas phase mechanisms. Interactions between the additives and the epoxy resin result in a change in the decomposition pathways and an increased char formation. The release of phosphorous products results in significant flame inhibition. The fire properties achieved are thus interesting with respect to industrial exploration. KW - Flame retardance KW - Thermosets KW - Composites KW - Thermogravimetric analysis (TGA) KW - Pyrolysis KW - High performance polymers KW - Epoxy resin PY - 2007 SN - 0021-8995 SN - 1097-4628 VL - 104 IS - 4 SP - 2260 EP - 2269 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-14573 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Balabanovich, Aliaksandr A1 - Knoll, Uta A1 - Braun, Ulrike A1 - Schartel, Bernhard T1 - Novel Phosphorus-containing Hardeners with Tailored Chemical Structures for Epoxy Resins: Synthesis and Cured Resin Properties N2 - A comparative evaluation of systematically tailored chemical structures of various phosphorus-containing aminic hardeners for epoxy resins was carried out. In particular, the effect of the oxidation state of the phosphorus in the hardener molecule on the curing behavior, the mechanical, thermomechanical, and hot-wet properties of a cured bifunctional bisphenol-A based thermoset is discussed. Particular attention is paid to the comparative pyrolysis of neat cured epoxy resins containing phosphine oxide, phosphinate, phosphonate, and phosphate (with a phosphorus content of about 2.6 wt %) and of the fire behavior of their corresponding carbon fiber-reinforced composites. Comparatively faster curing thermosetting system with an enhanced flame retardancy and adequate processing behavior can be formulated by taking advantage of the higher reactivity of the phosphorus-modified hardeners. For example, a combination of the high reactivity and of induced secondary crosslinking reactions leads to a comparatively high Tg when curing the epoxy using a substoichiometric amount of the phosphinate-based hardener. The overall mechanical performance of the materials cured with the phosphorus-containing hardeners is comparable to that of a 4,4-DDS-cured reference system. While the various phosphorus-containing hardeners in general provide the epoxy-based matrix with enhanced flame retardancy properties, it is the flame inhibition in the gas phase especially that determines the improvement in fire retardancy of carbon fiber-reinforced composites. In summary, the present study provides an important contribution towards developing a better understanding of the potential use of such phosphorus-containing compounds to provide the composite matrix with sufficient flame retardancy while simultaneously maintaining its overall mechanical performance on a suitable level. KW - Flame retardance KW - Organo-phosphorus compounds KW - Fracture toughness PY - 2007 SN - 0021-8995 SN - 1097-4628 VL - 105 IS - 5 SP - 2744 EP - 2759 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-15071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abou-Ras, D. A1 - Caballero, R. A1 - Fischer, C.-H. A1 - Kaufmann, C.A. A1 - Lauermann, I. A1 - Mainz, R. A1 - Mönig, H. A1 - Schöpke, A. A1 - Stephan, C. A1 - Streeck, C. A1 - Schorr, S. A1 - Eicke, A. A1 - Döbeli, M. A1 - Gade, B. A1 - Hinrichs, J. A1 - Nunney, T. A1 - Dijkstra, H. A1 - Hoffmann, V. A1 - Klemm, D. A1 - Efimova, V. A1 - Bergmaier, A. A1 - Dollinger, G. A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Rockett, A.A. A1 - Perez-Rodriguez, A. A1 - Alvarez-Garcia, J. A1 - Izquierdo-Roca, V. A1 - Schmid, T. A1 - Choi, P.-P. A1 - Müller, M. A1 - Bertram, F. A1 - Christen, J. A1 - Khatri, H. A1 - Collins, R.W. A1 - Marsillac, S. A1 - Kötschau, I. T1 - Comprehensive comparison of various techniques for the analysis of elemental distributions in thin films N2 - The present work shows results on elemental distribution analyses in Cu(In,Ga)Se2 thin films for solar cells performed by use of wavelength-dispersive and energy-dispersive X-ray spectrometry (EDX) in a scanning electron microscope, EDX in a transmission electron microscope, X-ray photoelectron, angle-dependent soft X-ray emission, secondary ion-mass (SIMS), time-of-flight SIMS, sputtered neutral mass, glow-discharge optical emission and glow-discharge mass, Auger electron, and Rutherford backscattering spectrometry, by use of scanning Auger electron microscopy, Raman depth profiling, and Raman mapping, as well as by use of elastic recoil detection analysis, grazing-incidence X-ray and electron backscatter diffraction, and grazing-incidence X-ray fluorescence analysis. The Cu(In,Ga)Se2 thin films used for the present comparison were produced during the same identical deposition run and exhibit thicknesses of about 2 µm. The analysis techniques were compared with respect to their spatial and depth resolutions, measuring speeds, availabilities, and detection limits. KW - Elemental distributions KW - Comparison KW - Depth profiling KW - Chemical mapping KW - Thin films KW - Solar cells KW - Chalcopyrite-type KW - Cu(In,Ga)Se2 PY - 2011 DO - https://doi.org/10.1017/S1431927611000523 SN - 1431-9276 SN - 1435-8115 VL - 17 IS - 5 SP - 728 EP - 751 PB - Cambridge University Press CY - New York, NY AN - OPUS4-24506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -