Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-49138 Vortrag Pötzsch, Sina Beständigkeit von Elastomeren bei Einsatz im Heizölgemisch mit 20 % Biodiesel (B20) bei unterschiedlichen Temperaturen unter statischen und verpressten Bedingungen Aus Rapsöl gewonnener Biodiesel ist eine umweltfreundliche Alternative zu fossilen Energiequellen. In der Europäischen Union, in der 80 % der ölhaltigen Brennstoffe importiert werden müssen, besteht zudem ein Interesse, die Abhängigkeit von exter-nen Ölversorgern zu reduzieren. Bei jeder Veränderung der Zusammensetzung eines Brennstoffs muss auch die Ma-terialverträglichkeit gewährleistet bleiben. Es stellt sich die Frage, ob Elastomere im Vergleich zu reinem Heizöl auch in Heizöl mit 20 % Biodiesel (B20) beständig sind. Die Polarität des Biodiesels erhöht die Quellung und fördert die Permeation und Ex-traktion. Sowohl Quellung als auch Extraktion bedingen Änderungen der physikali-schen Eigenschaften der Elastomere. Extraktion verändert die chemische des Heiz-öls. Diese chemischen Veränderungen können auch den Abbau (Hydrolyse und Oxi-dation) der Polymere durch das Herauslösen von Additiven und Stabilisatoren be-schleunigen. Ziel dieser Arbeit war die Bestimmung der Beständigkeit der Elastomere ACM (Poly-acrylatkautschuk), HNBR (Hydrierter Acrylnitrilbutadienkautschuk), FKM (Fluorkaut-schuk) und PUR (Polyurethan) in Heizöl und im Heizölgemisch B20. Prüfkörper der Elastomere wurden für 42 Tage (Härteprüfung) und 84 Tage (Zugprü-fung) bei 40 °C ausgelagert. Anschließend wurde die Änderung der Masse, Shore Härte A, Zugfestigkeit, und Reißdehnung bezogen auf die Werte vor der Aus-lagerung bestimmt. Die weniger zur Quellung neigenden Elastomere FKM und HNBR wurden zusätzlich bei 70 °C ausgelagert. Um die Elastomere im verpressten Zustand zu testen, wurde der Druckverformungs-rest nach DIN ISO 815 bestimmt. Hierzu wurden zylindrische Prüfkörper aus ACM, HNBR und FKM verpresst und in Heizöl und Heizöl mit 20 % FAME für 3, 7, 14, 28, 56 und 90 Tage bei 40 °C ausgelagert. Anschließend wurde über die Dickenmes-sung der Druckverformungsrest ermittelt. Zum Vergleich wurden Prüfkörper verpresst und ohne Medium bei 40 °C ausgelagert. In den internationalen Normen wurde kein Grenzwert für die Veränderung der Zugei-genschaften und der Härte für eine positive Bewertung der Beständigkeit festgelegt. Deshalb wurde in der BAM ein Grenzwert von 15 % für die Beständigkeitsbewertung herangezogen. Bei 40 °C lag die Änderung der Zugeigenschaften und der Shore Härte von ACM, HNBR und FKM in Heizöl und in B20 unter 15 %. Folglich sind ACM, HNBR und FKM bei 40 °C in Heizöl und in B20 beständig. PUR ist bei 40 °C in Heizöl beständig, je-doch nicht für eine Verwendung in B20 geeignet, da sich die Zugfestigkeit und Reiß-dehnung um 50 % vermindert haben. Bei 70 °C ist FKM in Heizöl und B20 beständig, wohingegen HNBR an seine Einsatz-grenzen gelangt und unbeständig ist, in B20 haben sich die Zugfestigkeit um 40 % und die Reißdehnung um 50 % reduziert. 2019 Merseburger Elastomertage - elastoMER 2019 Merseburg, Germany 25.09.2019 26.09.2019 2019-09-30 OPUS4-49139 Buchkapitel Leinitz, Sarah; Lu, Z.; Becker, S.; Stephan, D.; von Klitzing, R.; Schmidt, Wolfram Mechtcherine, V.; Khayat, K.; Secrieru, E. Influence of different accelerators on the rheology and early hydration of cement paste Special applications like pumping, spraying or printing of concrete require the precise adjustment of very specific rheological properties at different time steps during the casting process. Superplasticizers such as polycarboxylate ethers (PCE) can be used to obtain the required flowability, which, possibly in combination with additional rheology modifying admixtures, generate the required specified consistency. However, after the application, the concrete should change the rheological properties immediately in order to avoid deformations at rest. Therefore, the use of accelerators can be effective. Accelerators influence the hydration of cementitious materials, and thus the rheological properties over the course of time and the setting. In this paper, the influence of different accelerators on the rheology and early hydration of cement paste as well as the interaction of accelerator and PCE are presented. Methods like rheometry, needle penetration tests and practical Tests like spread flow were applied. The used accelerators showed accelerating behavior on the cement pastes without and in the presence of PCE. At the same time an influence on the rheology could be observed. This effect was less in the mixes with PCE, especially at the highest water/cement ratio (w/c). 1 Springer RILEM Bookseries 2019 Rheology and Processing of Construction Materials 23 978-3-030-22565-0 106 115 10.1007/978-3-030-22566-7 2019-09-30 OPUS4-49141 Posterpräsentation Wilbig, Janka Quality Aspects of Additively Manufactured Medical Implants - Defect Detection in Lattice Parts Additive Manufacturing technologies are developing fast to enable a rapid and flexible production of parts. Tailoring products to individual needs is a big advantage of this technology, which makes it of special interest for the medical device industry and the direct manufacturing of final products. Due to the fast development, standards to assure reliability of the AM process and quality of the printed products are often lacking. The EU project Metrology for Additively Manufactured Medical Implants (MetAMMI) is aiming to fill this gap by investigating alternative and cost efficient non-destructive measurement methods. 2019 yCAM Forum Mons, Belgium 03.03.2019 05.03.2019 2019-09-30 OPUS4-49142 Zeitschriftenartikel Hlavacek, Petr; Gluth, Gregor; Lüchtenborg, Jörg; Sturm, Patrick; Mühler, T.; Kühne, Hans-Carsten; Günster, Jens A Novel Approach to Additive Manufacturing of Alkali-activated Materials: Laser-induced Slip Casting (LIS) of Lithium Aluminate/Silica Slurries Additive manufacturing of alkali-activated materials currently attracts a lot of attention, because of the possibility to produce customized high-performance elements for a range of applications, potentially being more resource-efficient than conventionally produced parts. Here, we describe a new additive manufacturing process for alkali-activated materials that is based on selective laser-heating of lithium aluminate/microsilica slurries. The new process-material combination allows to manufacture elements with complex geometries at high building rates and high accuracy. The process is versatile and transferrable to structures of sizes differing by orders of magnitude. The mechanical strength of the obtained materials was in the range of values reported for conventional metakaolin-based geopolymers, and superior to what has been hitherto reported for alkali-activated materials produced by additive manufacturing. This mechanical performance was obtained despite the fact that the degree of reaction of the lithium aluminate and the microsilica was low, suggesting that significant reactions took place only at the surface of the microsilica particles. Techna Group 2019 Ceramics in Modern Technologies 1 2 138 144 10.29272/cmt.2018.0011 2019-09-30 OPUS4-49145 Vortrag Spaltmann, Dirk Challenges for the design of a universal tribological database for materials Renowned institutions in the field of tribology combine their testing and analytical capabilities with experts in materials/process information management technology to provide the respective services in Europe (i-TRIBOMAT). This requires a centralized materials information management system or the standardised capture, consolidation and harmonization of tribological information. 2019 60. Tribologie-Fachtagung Göttingen, Germany 23.09.2019 25.09.2019 2019-09-30 OPUS4-49147 Beitrag zu einem Tagungsband Spaltmann, Dirk; Kogia, M.; Liedtke, S.; Dykeman, D.; Gradt, Thomas Challenges for the design of a universal tribological database for materials Renowned institutions in the field of tribology combine their testing and analytical capabilities with experts in materials/process information management technology to provide the respective Services in Europe (i-TRIBOMAT). This requires a centralized materials information management system or the standardised capture, consolidation and harmonization of tribological information. Jülich GfT (Gesellschaft für Tribologie) 2019 Reibung, Schmierung unf Verschleiß 978-3-9817451-4-6 60. Tribologe-Fachtagung Goettingen, Germany 23.09.2019 25.09.2019 37/1 37/5 2019-10-16 OPUS4-49210 Zeitschriftenartikel Kricheldorf, H.; Weidner, Steffen SnOct 2-Catalyzed Syntheses of Cyclic Poly (l-lactide) s with Catechol as Low-Toxic Co-catalyst Polymerizations of l-lactide in bulk at 160 or 180 °C were performed with 1/1 mixtures of catechol (CA) or 4-tert-butylcatechol (BuCA) and tin(II)-2-ethylhexanoate (SnOct2) as catalysts and a variation of the Lac/Cat ratio. Weight average molar masses (Mw) up to 170,000 g mol−1 were obtained with CA and up to 120,000 g mol−1 with BuCA. The cyclic structure of the resulting poly(l-lactide)s was proven by MALDI-TOF mass spectrometry and by comparison of their hydrodynamic volumes with those of commercial linear poly(l-lactide)s. The predominance of even-numbered cycles increased with lower temperatures and shorter polymerization times. This fnding indicates that the cyclic architecture is the results of a ring-expansion polymerization mechanism. Addition of silylated BuCA as co-catalyst was less favorable than addition of free BuCA. Springer 2019 Journal of Polymers and the Environment 10924 10.1007/s10924-019-01545-5 2019-10-07 OPUS4-49211 Zeitschriftenartikel Kricheldorf, Hans; Weidner, Steffen About the influence of salicylic acid on tin(II)octanoate-catalyzed ring opening polymerizationof L-lactide L-Lactide was polymerized in bulk with tin(II)2-ethylhexanoate SnOct2) as catalyst and salicylic acid as cocatalyst. The Lac/Cat ratio, Cocat/Cat ratio, temperature and time were varied. Increasing Cocat/Cat ratios reduced both,polymerization rate and molecular weight. However,under optimized conditions high molar mass (Mw up to 178,000), colorless, cyclic polylactides were formed in a short time. A few polymerizations performed at 160 and 180°C with the combination of SnOct2 and silylated salicylic acid gave similar results. Neat tin II) salicylate was prepared from SnOct2 and used for REPs of L-lactide in bulk, but the results were not better than those obtained from combinations of SnOct2 and salicylic acid. Furthermore, dibutyltin salicylate was synthesized and used as catalyst for polymerizations of L-lactide in bulk at temperatures varying from 102 to 160°C. Cyclic polylactides with Mw's up to 40,000 were the main reaction products. At 100-102°C a predominance of odd-numbered cycles was found proving a REP mechanism. Elsevier Ltd. 2019 European Polymer Journal 119 37 44 10.1016/j.eurpolymj.2019.07.003 2019-10-07 OPUS4-49212 Posterpräsentation Falk, Florian Microstructural impact on high temperature oxidation behavior of Fe-Cr-C model alloys Chromia forming high alloyed ferritic-austenitic steels are being used as boiler tube materials in biomass and coal-biomass co-fired power plants. Despite thermodynamic and kinetic boundary conditions, microstructural features such as grain orientation, grain sizes or surface deformation contribute to the oxidation resistance and formation of protective chromium-rich oxide layers. This study elucidates the impact of microstructure such as the grain size and number of carbide precipitates on high temperature oxidation at 650°C in 0.5% SO2 atmosphere. Cold-rolled Fe-16Cr-0.2C material was heat-treated to obtain two additional microstructures. After exposure to hot and reactive gases for 10 h < t < 1000 h layer thicknesses and microstructure of oxide scales are observed by scanning electron microscopy and Energy-dispersive X-ray spectroscopy. The two heat treated alloys showed reasonable oxidation resistance after 1000 h of exposure. The oxidation rate was substantially higher for the alloy with a duplex matrix after heat treatment compared to the fine-grained material. 2019 Gordon Research Conference New London, New Hampshire, USA 21.07.2019 26.07.2019 2019-10-09 OPUS4-49213 Vortrag Falk, Florian The impact of water vapour on high-temperature surface degradation by sulfurous gases of ferritic alloys Sulfur and water have a fundamental impact on the corrosion rate and potential failure of materials. It is therefore necessary to understand the mechanisms, rates, and potential means of transport, as well as the reactions of these elements with an alloy. This work investigates the effect of water vapor in the initial stages of SO2 corrosion of an ferritic model alloy containing 9 wt% Cr and 0.5 wt% Mn. The exposure experiments were studied at 650°C in situ under laboratory conditions using energy-dispersive x-ray diffraction analysis. Two separate experiments were run, one with a 99.5% Ar + 0.5% SO2 atmosphere and one with a 69.5% Ar + 0.5% SO2 + 30% H2O atmosphere. With a wet atmosphere, the alloy formed a scale with decreasing oxygen content towards the scale-alloy interface. Sulfides were identified above and below a (Fe, Cr)3O4 layer in the inner corrosion zone. In contrast to this, the overall scale growth was slower in a dry SO2 atmosphere. 2019 EUROCORR Barceló Sevilla Renacimiento, Seville, Spain 09.09.2019 13.09.2019 2019-10-09