TY - CONF A1 - Wehmann, N. A1 - Lenting, C. A1 - Stawski, T. M. A1 - Agudo Jácome, Leonardo T1 - Anhydrite formation in planetary surface environments - The case of the Atacama Desert N2 - Gypsum (CaSO4∙2H2O), bassanite (CaSO4∙0.5H2O), and anhydrite (CaSO4) are essential evaporite minerals for the evolution of hyper-arid surface environments on Earth and Mars (Voigt et al. 2019; Vaniman et al. 2018). The formation mechanism of especially anhydrite has been a matter of scientific debate for more than a century (van’t Hoff et al. 1903). To date, there exists no model that can reliably predict anhydrite formation at earth’s surface conditions. While thermodynamics favor its formation, it is hardly achieved on laboratory time scales at conditions fitting either the Atacama Desert on Earth, or the surface of Mars (Wehmann et al. 2023). In light of most recent developments (e.g. Stawski et al. 2016), that advocate for a complex, non-classical nucleation mechanism for all calcium sulphates, we present an analysis of natural samples from the Atacama Desert to identify key features that promote the nucleation and growth of anhydrite under planetary surface conditions. Our analyses reveal at least three distinct anhydrite facies, with differing mineralogy and micro- to nano-structures. The facies are (1) aeolian deposits with sub-μm grain sizes, (2) (sub-)surface nodules that formed from aeolian deposits and (3) selenites with secondary anhydrite rims. Possible mechanisms of their formation will be discussed. T2 - 10th Granada-Münster Discussion Meeting CY - Münster, Germany DA - 29.11.2023 KW - Calcium sulfates KW - Nucleation KW - Planetary surface KW - Hyper-arid PY - 2023 AN - OPUS4-59111 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrhan, Anne T1 - Transport of sulfadiazine in soil columns - Experiments an model simulations T2 - International Conference on Pharmaceuticals in the Environment CY - York, England DA - 2007-09-19 PY - 2007 AN - OPUS4-15687 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrhan, Anne T1 - Analysis of organic sulfur compounds in biogas T2 - European Meeting on environmental Chemistry CY - Girona, Spain DA - 2008-12-03 PY - 2008 AN - OPUS4-18120 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrstedt, Klaus-Dieter T1 - Update German accident prevention regulation BGV B4 (DGUV 13) - (Organic Peroxides, OP) N2 - Transposition of regulations of the (German) employer’s liability insurance association (BGV’n) into Federal responsibility. Fundamentals are regulated in the German Hazardous Substances Ordinance (GefStoffV). Prospectively, some definitions and more details are specified in a Technical Rule (TRGS 741 „Organic Peroxides“). A second project outline was discussed in 2014; because of some formal objections concerning the process and, particularly, the membership in a project group, no progress et al. since 2014. Nevertheless, the BGV B4 is still valid. Because of some new findings and new test results a revision and Supplementation of the table of assignments of OP to risk (storage) groups was required. T2 - IGUS EOS Meeting CY - Shangahi, China DA - 09.04.2018 KW - Substances KW - GefStoffV KW - Risk groups KW - BGV PY - 2018 AN - OPUS4-45275 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrstedt, Klaus-Dieter A1 - Blankenhagel, Paul T1 - Organic peroxide fireballs - Report of progress N2 - Summary of recent research activities at BAM concerning large scale fireballs of organic peroxides (OP). Videos of the tests performed in Nanjing, China, are presented. A new model for OP fireball diameter, duration, height and SEP is proposed based on all experiments. In addition, small scale test results using DTBP and heptane are presented. Finally, CFD simulation is used to predict the fireball parameters: diameter, duration and height. T2 - IGUS EOS Meeting CY - Shanghai, China DA - 09.04.2018 KW - Fireball KW - Organic peroxide KW - Thermal radiation KW - Safety distances PY - 2018 AN - OPUS4-45276 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrstedt, Klaus-Dieter A1 - XU, S. A1 - Liu, Dingxin A1 - Krebs, Holger T1 - 2015 Tianjin Explosions N2 - In 2015 a series of explosions occurred at a container storage station at the Port of Tianjin, China, on Wednesday, 12 August 2015, that killed over one hundred people and injured hundreds of firemen and others. The first two explosions happened within 30 seconds of each other at the facility. The second explosion was larger and involved the detonation of about 800 tons of ammonium nitrate. The cause of the explosions was not known at first, but an investigation of the Chinese authorities concluded in February 2016 that an overheated container of dry nitrocellulose was the cause of the initial explosion. Colleagues of the Nanjing University of Science and Technology and BAM worked together to analyze the reasons and the process of that incident based on knowledge about the properties of the involved substances, particularly ammonium nitrate and nitrocellulose, and potential mechanism of initiation and propagation. T2 - IGUS EOS Meeting CY - Basel, Switzerland DA - 11.04.2016 KW - Tianjin KW - Nitrocellulose KW - Ammonium nitrate PY - 2016 AN - OPUS4-35861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrstedt, Klaus-Dieter T1 - Identifizierung gefährlicher exotherm zersetzlicher Stoffe T2 - DECHEMA-Weiterbildungskurs "Sicherheit chemischer Reaktionen" CY - Berlin, Deutschland DA - 2015-03-23 PY - 2015 AN - OPUS4-33003 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrstedt, Klaus-Dieter A1 - Krebs, Holger A1 - Mishra, Kirti Bhushan T1 - Boiling Liquid Expanding Vapor Explosion (BLEVE) of peroxy-fuels: Experiments and Computational Fluid Dynamics (CFD) simulation T2 - IGUS Energetic and Oxidising Substances (EOS) Working Group Meeting CY - Ottawa, Canada DA - 2015-05-06 PY - 2015 AN - OPUS4-33377 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrstedt, Klaus-Dieter A1 - Krebs, Holger A1 - Berger, Anka A1 - Heitkamp, D. T1 - MNB, DNT and MNT - Relevant safety aspects T2 - Mononitrobenzene and Dinitrotoluene Safety Conference CY - Lyon, France DA - 2015-04-14 PY - 2015 AN - OPUS4-33383 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrstedt, Klaus-Dieter A1 - Schälike, Stefan A1 - Vela-Wallenschus, Iris A1 - Schönbucher, A. T1 - Wechselwirkende KW- und Peroxid-Poolfeuer T2 - Sitzung ProcessNet Arbeitsausschuss "Reaktionstechnik sicherheitstechnisch schwieriger Prozesse" CY - Darmstadt, Germany DA - 2014-03-11 PY - 2014 N1 - Geburtsname von Vela-Wallenschus, Iris: Vela, I. - Birth name of Vela-Wallenschus, Iris: Vela, I. AN - OPUS4-30447 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -