TY - JOUR A1 - Meretz, S. A1 - Auersch, W. A1 - Marotzke, Christian A1 - Schulz, Eckhard A1 - Hampe, Andreas T1 - Investigation of Morphology-dependent Fracture Behaviour with the Single-fibre Pull-out Test PY - 1993 SN - 0266-3538 VL - 48 SP - 285 EP - 290 PB - Elsevier CY - Barking AN - OPUS4-6821 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Díez, I. A1 - Emmerling, Franziska A1 - Malz, Frank A1 - Jäger, Christian A1 - Schulz, B. A1 - Orgzall, I. T1 - Origin of templating processes in polypyrrole synthesis N2 - The supermolecular mechanism of the template-mediated oxidative polymerization of pyrrole is investigated in detail. It is shown for the first time that 2,5-bis(pyrrol-2-yl)pyrrolidyl complexes with aromatic sulfonic acids such as %#946;-naphtalenesulfonic acid or para-toluenesulfonic acid are formed in the early polymerization step. The crystalline acid–base complexes are isolated and their crystal structures are analyzed. A 2,5-bis(pyrrol-2-yl)pyrrolidyl cation is common to both complexes and forms an inner salt with the sulfonic acid anion. As concluded from NMR investigations the synthesis using sulfonic acids results in a high stereo selectivity with respect to the trans conformation of the pyrrolidyl ring compared with the classical synthesis routine of this compound using hydrochloric acid. The needle-like crystals of the complexes act as hard templates during the next step of the polymerization and result in tubular morphologies of the polypyrrole. KW - Polypyrrole KW - Pyrrole complex PY - 2008 DO - https://doi.org/10.1016/j.matchemphys.2008.05.057 SN - 0254-0584 VL - 112 IS - 1 SP - 154 EP - 161 PB - Elsevier CY - Amsterdam AN - OPUS4-17859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartoszek, M. A1 - Eckelt, R. A1 - Jäger, Christian A1 - Kosslick, H. A1 - Pawlik, Alf A1 - Schulz, A. T1 - Mesoporous silica-aluminas derived from precipitation: a study of the acidity, textural properties and catalytic performance KW - Silica-alumina KW - Solid state NMR KW - Acidity KW - Silicates KW - Tetrahedral aluminium PY - 2009 DO - https://doi.org/10.1007/s10853-009-3580-y SN - 0022-2461 SN - 1573-4803 VL - 44 IS - 24 SP - 6629 EP - 6636 PB - Springer Science + Business Media B.V. CY - Norwell, Mass. AN - OPUS4-20462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Weimann, Karin A1 - Matyschik, Jan A1 - Adam, Christian A1 - Schulz, T. A1 - Linß, E. A1 - Müller, A. T1 - Optimierung des Rückbaus/Abbruchs von Gebäuden zur Rückgewinnung und Aufbereitung von Baustoffen unter Schadstoffentfrachtung (insbes. Sulfat) des RCMaterials sowie ökobilanzieller Vergleich von Primär- und Sekundärrohstoffeinsatz inkl. Wiederverwertung N2 - Aufgrund der großen Massenströme ist das Recycling von Baurestmassen von besonderer Bedeutung für die Schonung von natürlichen Ressourcen. Eine wichtige Voraussetzung für ein hochwertiges Recycling, wie z.B. eine Wiederverwertung von aufbereitetem Bauschutt/Altbeton als rezyklierte Gesteinskörnung im Hochbau, ist die Einhaltung von Grenzwerten für Stör- und Schadstoffe. Dabei steht der Sulfatgehalt im Eluat von Bauschutt besonders im Fokus. In der vorliegenden Studie wird untersucht, wie durch die Optimierung von Abbrucharbeiten und Bauschuttaufbereitung hochwertige Gesteinskörnungen aus Altbeton gewonnen werden können. Anhand von Literatur- und Datenrecherchen werden zunächst Sulfatquellen in Gebäuden sowie verfügbare Abbruch- und Aufbereitungstechniken zusammengestellt. Am Beispiel von unterschiedlichen Gebäudetypen werden Szenarien für selektiven und nicht selektiven Abbruch (Schwerpunkt: Sulfatentfachtung) in Hinblick auf ihre Umweltwirkungen ökobilanziell bewertet. Ergänzt werden diese Bewertungen durch Untersuchungen an realen Bauschuttmaterialien und Abbruchprojekten. Auf dieser Basis werden Handlungsempfehlungen für die Gewinnung von hochwertigen RC-Gesteinskörnungen erarbeitet und diskutiert.----------------------------------------------------------------------------------------- Due to the large-scale mass flow of construction and demolition wastes, the recycling of those residues is of particular importance for the conservation of natural resources. An important requirement for recycling on a high level, like the reuse of crushed concrete as recycled concrete aggregate, is the observation of limits for hazardous substances and impurities. This study is focusing on the reduction of sulphates in the eluate of crushed concrete. An investigation of possibilities to optimize demolition and dismantling as well as treatment of crushed concrete with the objective of gaining recycled concrete aggregates of high quality. Based on a literature research and a data review the origins of sulfates in buildings and also the availability of techniques for demolition and treatment of crushed concrete are listed and evaluated. Using the examples of different building types scenarios for selective dismantling and non-selective demolition (focused on reducing suphates) are evaluated in terms of affecting the environment. In addition samples from real demolition construction sites and plants for treatment of construction rubble were investigated. Based on these results recommendations for the production of high quality recycled concrete aggregates are worked out. KW - Bauschuttaufbereitung KW - Abbruch KW - Ökobilanzielle Bewertung KW - RC-Beton KW - Gips KW - Abbruchverfahren KW - Hochwertiges Recycling KW - Ökobilanzielle Betrachtung KW - Sulfatentfachtung KW - Demolition/dismantling KW - Treatment of C&D wastes KW - High-grade recycling KW - Environmental LCA KW - Reduction of sulphates PY - 2012 UR - http://www.umweltbundesamt.de/publikationen/optimierung-des-rueckbausabbaus-von-gebaeuden-zur SN - 1862-4804 SP - 1 EP - 227 PB - Umweltbundesamt CY - Dessau-Roßlau AN - OPUS4-26999 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hieu, D.T. A1 - Kosslick, H. A1 - Riaz, M. A1 - Schulz, A. A1 - Springer, A. A1 - Frank, M. A1 - Jäger, Christian A1 - Minh Thu, N.T. A1 - Son, L.T. T1 - Acidity and Stability of Bronsted Acid Sites in Green Clinoptilolite Catalysts and Catalytic Performance in the Etherification of Glycerol N2 - Natural zeolite clinoptilolite CLIN with a framework ratio of Si/Al ≥ 4 containing mainly potassium and calcium ions in its internal channel system was used as a starting material. The acidic HCLIN catalysts were prepared under soft conditions avoiding the use of environmental less benign mineral acids. The starting material was ion exchanged using a 0.2 M aqueous ammonium nitrate solution at a temperature 80 ◦C for 2 h. The obtained NH4CLIN was converted into the acid HCLIN catalyst by calcination at 300–600 ◦C. The obtained samples were characterized by XRD, FTIR, SEM/TEM, AAS, and EDX element mapping. The state of aluminium and silicon was studied by 27Al- and 29SiMAS NMR spectroscopy. The textural properties of the catalysts were investigated by nitrogen adsorption and desorption measurements. The Brønsted acidity of the HCLIN catalysts was studied by temperature-programmed decomposition of the exchanged ammonium ions releasing ammonia as well as 1H MAS NMR, {1H–27Al} Trapdor, and {1H–27Al} Redor experiments. The strongly agglomerated samples were crystalline and thermally stable up to >500 ◦C. Although a part of the clinoptilolite framework is maintained up to 600 ◦C, a loss of crystallinity is already observed starting from 450 ◦C. The specific surface areas of the starting CLIN and ammonium exchanged NH4CLIN are low with ca. 26 m2/g. The pores are nearly blocked by the exchangeable cations located in the zeolite pores. The thermal decomposition of the ammonium ions by calcination at 400 ◦C causes an opening of the pore entrances and a markable increase in the specific micropore area and micropore volume to ca. 163 m2/g and 0.07 cm3/g, respectively. It decreases with further rising calcination temperature indicating some structural loss. The catalysts show a broad distribution of Brønsted acid sites (BS) ranging from weak to strong sites as indicated the thermal decomposition of exchanged ammonium ions (TPDA). The ammonium ion decomposition leaving BS, i.e., H+ located at Al–O–Si framework bridges, starts at ≥250 ◦C. A part of the Brønsted sites is lost after calcination specifically at 500 ◦C. It is related to the formation of penta-coordinated aluminium at the expense of tetrahedral framework aluminium. The Brønsted sites are partially recreated after repeated ammonium ion exchange. The catalytic performance of the acidic HCLIN catalysts was tested in the etherification of glycerol as a green renewable resource with different C1 -C4 alcohols. The catalysts are highly active in the etherification of glycerol, especially with alcohols containing the branched, tertiary alkyl groups. Highest activity is observed with the soft activated catalyst HCLIN300 (300 ◦C, temperature holding time: 1 min). A total of 78% conversion of glycerol to mono and di ether were achieved with tert-butanol at 140 ◦C after 4 h of reaction. The mono- and di-ether selectivity were 75% and 25%, respectively. The catalyst can be reused. KW - Etherification KW - Glycerol KW - Zeolite KW - Clinoptilolite KW - Bronsted acidity KW - Dehydroxylation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546982 DO - https://doi.org/10.3390/catal12030253 VL - 12 IS - 3 SP - 1 EP - 24 PB - MDPI AN - OPUS4-54698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulz-Forberg, Bernd A1 - Balke, Christian T1 - Ereignisauswertung bei der Störfallkommission (SFK) PY - 2005 VL - 6 SP - 53 EP - 55 PB - Vds Schadenverhütung Verl. CY - Köln AN - OPUS4-19434 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kosslick, H. A1 - Pitsch, I. A1 - Deutsch, J. A1 - Pohl, M.-M. A1 - Schulz, A. A1 - Vu, A.T. A1 - Nguyen, D.T. A1 - Frunza, L. A1 - Jäger, Christian T1 - Improved large mesoporous ordered molecular sieves - Stabilization and acid/base functionalization N2 - The preparation of nanoporous materials with enhanced stability using an improved synthesis route using reactive inorganic silica and alumina species is reported. This way improved mesoporous molecular sieves were obtained. The synthesized aluminum substituted mesoporous molecular materials (Al-MMS) contain very large pores of 50–200 Å size combined with an improved pore wall thickness. Increased wall thickness and Al substitution lead to an improved chemical stability against alkaline solution. The textural, structural and acid properties are investigated by physico-chemical methods. The catalytic performance acidic materials was tested in the benzoylation reaction; amino functionalized materials were studied in the base catalyzed Michael addition. KW - Nanoporous molecular sieve KW - Al substitution KW - Stability KW - Synthesis KW - Acidity KW - Catalysis PY - 2010 DO - https://doi.org/10.1016/j.cattod.2010.03.005 SN - 0920-5861 VL - 152 IS - 1-4 SP - 54 EP - 60 PB - Elsevier CY - Amsterdam AN - OPUS4-23960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Michael A1 - Gregor, Christian T1 - Assessment of state of residual stress of hybrid pressure vessels N2 - For fully carbon fibre wrapped pressure vessels with load sharing metallic liner (Type III), it was recognized that the state of residual stress given after the autofrettage process can change even if the vessel is stored without pressure. This change is influenced by temperature and time and has a direct effect on the residual lifetime of the vessel. To study the influence of the temperature on the state of residual stress an analytical model was applied which is based on the Classical Laminate Theory (CLT). According to the model, the critical conditions leading to a decrease in lifetime were identified. To confirm the results of the model temperature cycle tests were carried out. The results of the tests are compared with the analytical model and a finite element model. To investigate the influence of time on the state of residual stress, tests on vessels were performed. The tested vessels were aged without any pressure for a longer period of time after the autofrettage process. During these tests, the strain of the vessels was monitored. T2 - ASME 2009 Pressure vessels and piping conference CY - Prague, Czech Republic DA - 2009-07-26 KW - Pressure vessel KW - Residual stress KW - Composite material PY - 2009 SP - PVP2009-77993, 1-9 PB - American Society of Mechanical Engineers CY - New York AN - OPUS4-20052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weimann, Karin A1 - Adam, Christian A1 - Schulz, T. A1 - Linsz, E. T1 - Environmental evaluation of different ways to produce recycled concrete aggregates N2 - Due to the great quantities of construction and demolition waste in Europe, the reuse of building material waste as secondary raw materials is of particular importance. A recycling of building materials can meet the requirements of sustainability in several aspects: the extended time availability of primary raw materials and the related protection of natural resources as well as the saving of landfill sites. In recent years sulphates originating from gypsum in secondary building materials, made of construction and demolition waste, received growing attention. Sulphates are unwanted in secondary building materials for concrete production as well as for other use e.g. in unbounded layers. The content of gypsum resp. sulphates in secondary aggregates can be reduced by different methods. Depending on the type of material different steps for selective dismantling can be used to separate gypsum containing residues from concrete rubble. Furthermore some steps for the processing of building rubble are suitable for the reduction of sulphates in the produced aggregates. An environmental evaluation of different ways for the production of recycled concrete aggregates was performed with regard to a reduction of sulphates in the secondary building material. The use of techniques for selective dismantling was environmentally advantegous for the deconstruction of three investigated model houses. T2 - SUM2014 - 2nd Symposium on urban mining CY - Bergamo, Italy DA - 19.05.2014 KW - Recycling KW - Concrete aggregates KW - Building waste KW - Construction PY - 2014 SN - 9788862650311 SP - Session C 6, 1 EP - 8 AN - OPUS4-30825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wilke, Olaf A1 - Schulz, Christian A1 - Richter, Matthias T1 - Test chamber measurements for the robustness validation of the test method for the determination of VOC-emissions from construction products into indoor air T2 - Healthy Buildings 2012 - 10th International conference CY - Brisbane, Australia DA - 2012-07-08 KW - VOC KW - Emission studies KW - Product safety KW - Emission test chamber PY - 2012 SN - 978-1-921897-40-5 SP - 1 EP - 2 (1D.2) AN - OPUS4-27560 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -