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 OPUS4-20928 Forschungsbericht Joschko, M.; Reinhold, J.; Barkusky, D.; Wiemer, M.; Remus, R.; Busse, J.; Müller, H.-J.; Kiesel, J.; Gleixner, G.; Illerhaus, Bernhard; Kirchner, M.; Oehley, J.; Gerlach, F. Wirkung einer organischen Düngung mit Seeschlamm auf sandigem Boden im nordostdeutschen Trockengebiet Frankfurt/Main Landwirtschaftliche Rentenbank 2009 1 162 2016-02-19 OPUS4-38429 Zeitschriftenartikel Bungartz, M.; Maenz, S.; Kunisch, E.; Horbert, V.; Xin, L.; Gunella, F.; Mika, J.; Borowski, J.; Bischoff, S.; Schubert, H.; Sachse, A.; Günster, Jens; Illerhaus, Bernhard; Bossert, J.; Jandt, K. D.; Kinne, R. W.; Brinkmann, O. First-time systematic postoperative clinical assessment of a minimally invasive approach for lumbar ventrolateral vertebroplasty in the large animal model sheep Large animal models are highly recommended for meaningful preclinical studies, including the optimization of cement augmentation for vertebral body defects by vertebroplasty/kyphoplasty. The aim of this study was to perform a systematic characterization of a strictly minimally invasive in vivo large animal model for lumbar ventrolateral vertebroplasty. This is a prospective experimental animal study. Lumbar defects (diameter 5 mm; depth approximately 14 mm) were created by a ventrolateral percutaneous approach in aged, osteopenic, female sheep (40 Merino sheep; 6-9 years; 68-110 kg). L1 remained untouched, L2 was left with an empty defect, and L3 carried a defect injected with a brushite-forming calcium phosphate cement (CPC). Trauma/functional impairment, surgical techniques (including drill sleeve and working canula with stop), reproducibility, bone defects, cement filling, and functional cement augmentation were documented by intraoperative incision-to-suture time and X-ray, postoperative trauma/impairment scores, and ex vivo osteodensitometry, microcomputed tomography (CT), histology, static/fluorescence histomorphometry, and biomechanical testing. Minimally invasive vertebroplasty resulted in short operation times (28±2 minutes; mean±standard error of the mean) and X-ray exposure (1.59±0.12 minutes), very limited local trauma (score 0.00±0.00 at 24 hours), short postoperative recovery (2.95±0.29 hours), and rapid decrease of the postoperative impairment score to 0 (3.28±0.36 hours). Reproducible defect creation and cement filling were documented by intraoperative X-ray and ex vivo conventional/micro-CT. Vertebral cement augmentation and osteoconductivity of the CPC was verified by osteodensitometry (CPC>control), micro-CT (CPC>control and empty defect), histology/static histomorphometry (CPC>control and empty defect), fluorescence histomorphometry (CPC>control; all p<.05 for 3 and 9 months), and compressive strength measurements (CPC numerically higher than control; 102% for 3 months and 110% for 9 months). This first-time systematic clinical assessment of a minimally invasive, ventrolateral, lumbar vertebroplasty model in aged, osteopenic sheep resulted in short operation times, rapid postoperative recovery, and high experimental reproducibility. This model represents an optimal basis for standardized evaluation of future studies on vertebral augmentation with resorbable and osteoconductive CPC. Elsevier Inc. 2016 The Spine Journal 16 10 1263 1275 10.1016/j.spinee.2016.06.015 2016-11-24 OPUS4-44561 Beitrag zu einem Sammelband Gunella, F.; Kunisch, E.; Maenz, S.; Horbert, V.; Xin, L.; Mika, J.; Borowski, J.; Bischoff, S.; Schubert, H.; Sachse, A.; Illerhaus, Bernhard; Günster, Jens; Bossert, J.; Jandt, K. D.; Plöger, F.; Kinne, R. W.; Brinkmann, O.; Bungartz, M. Carragee, The GDF5 mutant BB-1 enhances the bone formation induced by an injectable, poly(l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming cement in a sheep defect model of lumbar osteopenia BACKGROUND CONTEXT: Targeted delivery of osteoinductive bone morphogenetic Proteins (eg, GDF5) in bioresorbable calcium phosphate cement (CPC), potentially suitable for vertebroplasty and kyphoplasty of osteoporotic vertebral fractures, may be required to counteract augmented local bone catabolism and to support complete bone regeneration. The biologically optimized GDF5 Mutant BB-1 may represent an attractive drug candidate for this purpose. PURPOSE: The aim of the current study was to test an injectable, poly (l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming CPC containing low-dose BB-1 in a sheep lumbar osteopenia model. STUDY DESIGN/ SETTING: This is a prospective experimental animal study. METHODS: Bone defects (diameter 5 mm) were generated in aged, osteopenic female sheep and were filled with fiber-reinforced CPC alone (L4; CPC+fibers) or with CPC containing different dosages. New York Elsevier 2018 The Spine Journal 18 2 357 369 10.1016/j.spinee.2017.10.002 2018-03-27 OPUS4-43237 Zeitschriftenartikel Gunella, F.; Kunisch, E.; Bungartz, M.; Maenz, S.; Horbert, V.; Xin, L.; Mika, J.; Borowski, J.; Bischoff, S.; Schubert, H.; Hortschansky, P.; Sachse, A.; Illerhaus, Bernhard; Günster, Jens; Bossert, J.; Jandt, K. D.; Plöger, F.; Kinne, R. W.; Brinkmann, O. Low-dose BMP-2 is sufficient to enhance the bone formation induced by an injectable, PLGA fiber-reinforced, brushite-forming cement in a sheep defect model of lumbar osteopenia BACKGROUND CONTEXT: Bioresorbable calcium phosphate cement (CPC) may be suitable for vertebroplasty/kyphoplasty of osteoporotic vertebral fractures. However, additional targeted de- livery of osteoinductive bone morphogenetic Proteins (BMPs) in the CPC may be required to counteract the augmented local bone catabolism and support complete bone regeneration. PURPOSE: This study aimed at testing an injectable, poly (l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming cement (CPC) containing low-dose bone morphogenetic Protein BMP-2 in a sheep lumbar osteopenia model. STUDY DESIGN/ SETTING: This is a prospective experimental animal study. METHODS: Bone defects (diameter 5 mm) were generated in aged, osteopenic female sheep and filled with fiber-reinforced CPC alone (L4; CPC+ fibers) or with CPC containing different dosages of BMP-2 (L5; CPC+ fibers + BMP-2; 1, 5, 100, and 500g BMP-2; n=5 or 6 each). The results were compared with those of untouched controls (L1). Three and 9 months after the operation, structural and functional effects of the CPC (±BMP-2) were analyzed ex vivo by measuring (1) bone Mineral density (BMD); (2) bone structure, that is, bone volume/total volume (assessed by micro-computed tomography [micro-CT] and histomorphometry), trabecular thickness, and trabecular number; (3) bone formation, that is, osteoid volume/bone volume, osteoid surface/bone surface, osteoid thickness, mineralizing surface/bone surface, mineral Apposition rate, and bone formation rate/bone surface; (4) bone resorption, that is, eroded surface/bone surface; and (5) compressive strength. RESULTS: Compared with untouched controls (L1), CPC+ fibers (L4) and/or CPC+ fibers + BMP-2(L5) significantly improved all parameters of bone formation, bone resorption, and bone structure. These effects were observed at 3 and 9 months, but were less pronounced for some parameters at 9 months. Compared with CPC without BMP-2, additional significant effects of BMP-2 were demonstrated for bone structure (bone volume/total volume, trabecular thickness, trabecular number) and formation (osteoid surface/bone surface and mineralizing surface/bone surface), as well as for the compressive strength. The BMP-2 effects on bone Formation at 3 and 9 months were dose-dependent, with 5-100g as the optimal dosage. CONCLUSIONS: BMP-2 significantly enhanced the bone formation induced by a PLGA fiber-reinforced CPC in sheep lumbar osteopenia. A single local dose as low as ≤100g BMP-2 was sufficient to augment middle to long-term bone formation. The novel CPC+ BMP-2 may thus represent an alternative to the bioinert, supraphysiologically stiff polymethylmethacrylate cement presently used to treat osteoporotic vertebral fractures by vertebroplasty/kyphoplasty. Elsevier Inc. 2017 The Spine Journal 17 11 1699 1711 10.1016/j.spinee.2017.06.005 2017-12-01 OPUS4-43239 Zeitschriftenartikel Bungartz, M.; Kunisch, E.; Maenz, S.; Horbert, V.; Xin, L.; Gunella, F.; Mika, J.; Borowski, J.; Bischoff, S.; Schubert, H.; Sachse, A.; Illerhaus, Bernhard; Günster, Jens; Bossert, J.; Jandt, K. D.; Plöger, F.; Kinne, R. W.; Brinkmann, O. GDF5 significantly augments the bone formation induced by an injectable, PLGA fiber-reinforced, brushite-forming cement in a sheep defect model of lumbar osteopenia BACKGROUND CONTEXT: Biodegradable calcium phosphate cement (CPC) represents a promising option for the surgical treatment of osteoporotic vertebral fractures. Because of augmented local bone catabolism, however, additional targeted delivery of bone morphogenetic proteins with the CPC may be needed to promote rapid and complete bone regeneration. PURPOSE: In the present study, an injectable, poly(l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming cement (CPC) containing the bone morphogenetic Protein GDF5 was tested in a sheep lumbar osteopenia model. STUDY DESIGN/SETTING: This is a prospective experimental animal study METHODS: Defined bone defects (diameter 5 mm) were placed in aged, osteopenic female sheep. Defects were treated with fiber-reinforced CPC alone (L4; CPC+ fibers) or with CPC containing different dosages of GDF5 (L5; CPC+ fibers + GDF5; 1, 5, 100, and 500g GDF5; n = 5 or 6 each). The results were compared with those of untouched controls (L1). Three and 9 months postoperation, structural and functional effects of the CPC (±GDF5) were assessed ex vivo by measuring (1) bone mineral density (BMD); (2) bone structure, that is, bone volume/total volume (assessed by micro-computed tomography and histomorphometry), trabecular thickness, and trabecular number; (3) bone formation, that is, osteoid volume/bone volume, osteoid surface/bone surface, osteoid thickness, mineralized surface/bone surface, mineral apposition rate, and bone formation rate/bone surface; (4) bone resorption, that is, eroded surface/bone surface; and (5) compressive strength. RESULTS: Compared with untouched controls (L1), both CPC+ fibers (L4) and CPC+ fibers + GDF5 (L5) numerically or significantly improved all parameters of bone formation, bone resorption, and bone structure. These significant effects were observed both at 3 and 9 months, but for some parameters they were less pronounced at 9 months. Compared with CPC without GDF5, additional significant effects of CPC with GDF5 were demonstrated for BMD and parameters of bone formation and structure (bone volume/total volume, trabecular thickness, and trabecular number, as well as mineralized surface/bone surface). The GDF5 effects were dose-dependent (predominantly in the 5-100g range) at 3 and 9 months. CONCLUSIONS: GDF5 significantly enhanced the bone formation induced by a PLGA fiber-reinforced CPC in sheep lumbar osteopenia. The results indicated that a local dose as low as ≤100g GDF5 may be sufficient to augment middle to long-term bone formation. The novel CPC+ GDF5 combination may thus qualify as an alternative to the bioinert, supraphysiologically stiff poly-(methyl methacrylate) cement currently applied for vertebroplasty/kyphoplasty of osteoporotic vertebral fractures. Elsevier Inc. 2017 The Spine Journal 17 11 1685 1698 10.1016/j.spinee.2017.06.007 2017-12-01 OPUS4-23548 Zeitschriftenartikel Perret, Birgit; Schartel, Bernhard; Stöß, K.; Ciesielski, M.; Diederichs, J.; Döring, M.; Krämer, J.; Altstädt, V. Novel DOPO-based flame retardants in high-performance carbon fibre epoxy composites for aviation Two novel, halogen-free, phosphorus-based oligomeric flame retardants are investigated in the commercial epoxy resin RTM6 and ~70 wt.% carbon fibre RTM6 composites (RTM6-CF) with respect to pyrolysis and fire behaviour. The flame retardants are based on 9,10-dihydro-9-oxy-10-phosphaphenanthrene-10-oxide (DOPO) units linked to the star-shaped aliphatic ground body tetra-[(acryloyloxy)ethyl] pentarythrit (DOPP), or heterocyclic tris-[(acryloyloxy)ethyl] isocyanurate (DOPI), respectively. The glass transition temperature is reduced by adding DOPP and DOPI, but the mechanical properties of the composites (e.g. interlaminar shear strength (ILSS) and Gc in mode I and II) remain unchanged. Decomposition models are proposed based on mass loss, evolved gas analysis (TG–FTIR) and condensed product analysis (hot stage cell within FTIR). The fire behaviour is investigated comprehensively (UL 94, limiting oxygen index (LOI) and cone calorimeter). Both flame retardants act in the gas phase through flame inhibition and in the condensed phase through charring. The UL 94 of RTM6 is improved from HB to V-1 and V-0; the LOI from 25% to 34–38%. Peak heat release rate (PHRR) and total heat evolved (THE) are lowered by 31-49% and 40–44%, respectively. Adding CF increases the residue, reduces the THE, but suppresses the charring due to RTM6 and flame retardants. Thus the THE of RTM6-CF is reduced by about 25% when DOPI and DOPP are added. However, UL 94: V-0 and LOI of 45% and 48% are achieved with ~0.6 wt.% phosphorus. Oxford Elsevier Ltd. 2011 European polymer journal 47 5 1081 1089 10.1016/j.eurpolymj.2011.02.008 2016-02-19 OPUS4-22162 Beitrag zu einem Sammelband Perret, Birgit; Schartel, Bernhard; Stöß, K.; Diederichs, J.; Ciesielski, M.; Döring, M.; Krämer, J.; Altstädt, V. Lewin, M. Novel phosphorus-based flame retardants for epoxy resins and carbon fiber composites: Decomposition mechanisms and fire behavior BCC Research Polytechnic Institute of NYU 2010 21st Annual conference on recent advances on flame retardancy of polymeric materials 21 1-59623-619-1 21st Annual conference on recent advances on flame retardancy of polymeric materials Stamford, USA 2010-05-24 2010-05-26 134 145 2016-02-19 OPUS4-22957 Zeitschriftenartikel Perret, Birgit; Schartel, Bernhard; Stöß, K.; Ciesielski, M.; Diederichs, J.; Döring, M.; Krämer, J.; Altstädt, V. A new halogen-free flame retardant based on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide for epoxy resins and their carbon fiber composites for the automotive and aviation industries The pyrolysis and fire behavior of halogen-free flame-retarded DGEBA/DMC, RTM6 and their corresponding 60 vol.-% carbon fibers (CF) composites were investigated. A novel phosphorous compound (DOPI) was used. Its action is dependent on the epoxy matrix. DGEBA/DMC and DOPI decompose independently of each other. Only flame inhibition occurs in the gas phase. RTM6 shows flame inhibition and a condensed phase interaction increasing charring. Both mechanisms decrease with increasing irradiance, whereas in RTM6-CF charring is suppressed at low ones. RTM6+DOPI shows a higher LOI (34.2%) than DGEBA/DMC+DOPI and a V-0 classification in UL 94. Adding CF only enhances the LOI, DOPI+CF leads to a superposition in LOI for DGEBA/DMC-CF+DOPI (31.8%, V-0) and a synergism for RTM6-CF+DOPI (47.7%, V-0). Weinheim Wiley-VCH Verl. 2011 Macromolecular materials and engineering 296 1 14 30 10.1002/mame.201000242 2016-02-19 OPUS4-38058 Zeitschriftenartikel Xin, L.; Bungartz, M.; Maenz, S.; Horbert, V.; Hennig, M.; Illerhaus, Bernhard; Günster, Jens; Bossert, J.; Bischoff, S.; Borowski, J.; Schubert, H.; Jandt, K.; Kunisch, E.; Kinne, R.; Brinkmann, O. Decreased extrusion of calcium phosphate cement versus high viscosity PMMA cement into spongious bone marrow—an ex vivo and in vivo study in sheep vertebrae Vertebroplasty or kyphoplasty of osteoporotic vertebral fractures bears the risk of pulmonary cement embolism (3.5%-23%) caused by leakage of commonly applied acrylic polymethylmethacrylate (PMMA) cement to spongious bone marrow or outside of the vertebrae. Ultraviscous cement and specific augmentation systems have been developed to reduce such adverse effects. Rapidly setting, resorbable, physiological calcium phosphate cement (CPC) may also represent a suitable alternative. PURPOSE: This study aimed to compare the intravertebral extrusion of CPC and PMMA cement in an ex vivo and in vivo study in sheep. STUDY DESIGN/SETTING: A prospective experimental animal study was carried out. METHODS: Defects (diameter 5 mm; 15 mm depth) were created by a ventrolateral percutane-ous approach in lumbar vertebrae of female Merino sheep (2-4 years) either ex vivo (n = 17) or in vivo (n = 6), and injected with: (1) CPC (L3); (2) CPC reinforced with 10% poly(l-lactide-co-glycolide) (PLGA) fibers (L4); or (3) PMMA cement (L5; Kyphon HV-R). Controls were untouched (L1) or empty defects (L2). The effects of the cement injections were assessed in vivo by blood gas analysis and ex vivo by computed tomography (CT), micro-CT (voxel size: 67 µm), histology, and biomechanical testing. Elsevier Inc. 2016 The Spine Journal 16 12 1468 1477 10.1016/j.spinee.2016.07.529 2017-01-03 OPUS4-34797 Beitrag zu einem Tagungsband Bernhard, J.; Madia, Mauro; Schork, B.; Kucharczyk, P.; Ngoula, D.; Baumgartner, J.; Schöne, Dieter Integrale bruchmechanische Ermittlung der Schwingfestigkeit von Schweißverbindungen: Validierung an Stumpfstößen und Kreuzstößen In diesem Beitrag soll das Validierungskonzept der IBESS-Prozedur, sowie erste Ergebnisse und Erkenntnisse der noch gegenwärtig laufenden Validierung vorgestellt werden. Die Vorstellung erfolgt dabei am Beispiel der im Projekt eingesetzten geschweißten Stumpfstoß- sowie Kreuzstoßverbindung. Neben der Validierung des analytischen bruchmechanischen Modells zur Ermittlung der Schwingfestigkeit, steht auch die Validierung von Kriterien zur Interaktion und Koaleszenz von kurzen Mehrfachrissen im Fokus. Düsseldorf DVS Media GmbH Deutscher Verband für Schweißen und Verwandte Verfahren 2015 DVS Congress 2015 - Große Schweißtechnische Tagung 978-3-945023-46-4 DVS Congress 2015 - Große Schweißtechnische Tagung Nuremberg, Germany 14.09.2015 17.09.2015 315 306 310 2016-02-20 OPUS4-34800 Beitrag zu einem Tagungsband Schork, B.; Zerbst, Uwe; Kucharczyk, P.; Bernhard, J.; Kaffenberger, M.; Baumgartner, J.; Oechsner, M. Imperfektionen für die schwingbruchmechanische Bewertung von Schweißverbindungen Bruchmechanischen Bewertungsmethoden liegt stets eine tatsachlich vorhandene oder fiktive Anfangsrisslange zu Grunde. Schweißverbindungen sind mit strukturellen Imperfektionen wie beispielsweise lnhomogenitaten in der Mikrostruktur und den Werkstoffeigenschaften behaftet, welche auf der Werkstoffseite berücksichtigt werden können. Imperfektionen wie der Kantenversatz und der Nahtübergangsradius, die als außere geometrische Imperfektionen aufgefasst werden können, haben vor allem Auswirkungen auf den Spannungszustand und werden daher auf der Lastseite erfasst. Innere geometrische Imperfektionen wie Einschlüsse oder Poren, von welchen Risse initiieren und sich ausbreiten, können als Ausgangsrissgröße aufgefasst werden. Im Teilprojekt A1 des Forschungsclusters IBESS wurden außere geometrische Imperfektionen an Schweißverbindungen ermittelt und statistisch ausgewertet. Des Weiteren wurden Schweißverbindungen fraktografisch im Rasterelektronenmikroskop (REM) bezüglich innerer geometrischer Imperfektionen untersucht, jedoch konnten aufgrund der hohen Schweißgütekeine schadigungsrelevanten inneren Imperfektionen (Ausgangsdefekte) detektiert werden. Um dennoch eine Ausgangsrisskonfiguration zu bestimmen, wurden "Heat-Tinting" Versuche eingesetzt, mit denen auf der Bruchflache verschiedene Anrissstadien markiert werden können. Mit dem .Heat-Tinting" Verfahren können sehr kleine Anrisse detektiert und in Abhangigkeit von der Beanspruchung frühe Anrisskonfigurationen ermittelt werden. Des Weiteren haben Zerbst und Madia im Teilprojekt A3 ein Modell entwickelt, mit dem für den Grundwerkstoff mittels zyklischer R-Kurven eine Ausgangsrissgröße rechnerisch ermittelt werden kann. Unter Verwendung der Ergebnisse aus den Versuchen zur Ermittlung der Anrissstadien soll dieses Modell validiert werden, um auch für Schweißverbindungen Anwendung zu finden. Düsseldorf DVS Media GmbH Deutscher Verband für Schweißen und Verwandte Verfahren 2015 DVS Congress 2015 - Große Schweißtechnische Tagung 978-3-945023-46-4 DVS Congress 2015 - Große Schweißtechnische Tagung Nuremberg, Germany 14.09.2015 17.04.2015 315 271 277 2016-02-20 OPUS4-52018 Zeitschriftenartikel Xin, L.; Mika, J.; Horbert, V.; Bischoff, S.; Schubert, H.; Borowski, J.; Maenz, S.; Huber, R.; Sachse, A.; Illerhaus, Bernhard; Kinne, R. W. Systematic postoperative assessment of a minimally-invasive sheep model for the treatment of osteochondral defects To assess the clinical course of a sheep stifle joint model for osteochondral (OC) defects, medial femoral condyles (MFC) were exposed without patella luxation using medial parapatellar skin (3-4 cm) and deep incisions (2-3 cm). Two defects (7 mm diameter; 10 mm depth; OC punch) were left empty or refilled with osteochondral autologous transplantation cylinders (OATS) and explanted after six weeks. Incision-to-suture time, anesthesia time, and postoperative wound or impairment scores were compared to those in sham-operated animals. Implant performance was assessed by X-ray, micro-computed tomography, histology, and immunohistology (collagens 1, 2; aggrecan). There were no surgery-related infections or patellar luxations. Operation, anesthesia, and time to complete stand were short (0.5, 1.4, and 1.5 h, respectively). The wound trauma score was low (0.4 of maximally 4; day 7). Empty-defect and OATS animals reached an impairment score of 0 significantly later than sham animals (7.4 and 4.0 days, respectively, versus 1.5 days). Empty defects showed incomplete healing and dedifferentiation/heterotopic differentiation; OATS-filled defects displayed advanced bone healing with remaining cartilage gaps and orthotopic expression of bone and cartilage markers. Minimally-invasive, medial parapatellar surgery of OC defects on the sheep MFC allows rapid and low-trauma recovery and appears well-suited for implant testing. Basel MDPI 2020 Life 10 12 1 14 urn:nbn:de:kobv:b43-520180 10.3390/life10120332 https://creativecommons.org/licenses/by/4.0/deed.de 2021-01-20 OPUS4-46858 Zeitschriftenartikel Zerbst, Uwe; Madia, Mauro; Schork, B.; Kaffenberger, M.; Oechsner, M.; Kucharzcyk, P.; Hensel, J.; Bernhard, J.; Tchuindjang, D. The effect of the local and global weld geometry as well as material defects on crack initiation and fatigue strength The paper provides an application of the IBESS approach to the investigation of the influence of various parameters of the global and local weld geometry as well as material defects on the fatigue strength of weldments. For this purpose, the global weld parameters, such as the weld toe radius, the flank angle, the excess weld metal, local secondary notches (in the present study as a measure of surface imperfections) and inclusions sizes have been determined as statistical distributions for different joint types and geometries and two steels of different strengths. The results are in line with literature data and reveal the potential of the theoretical approach to predict the correct trends. The combination with an advanced weld quality system has been demonstrated to be possible. Elsevier 2018 Engineering Fracture Mechanics 198 103 122 10.1016/j.engfracmech.2017.07.001 2018-12-04 OPUS4-46885 Monographie Zerbst, Uwe; Madia, Mauro; Schork, B.; Hensel, J.; Kucharczyk, P.; Tchoffo Ngoula, D.; Tchuindjang, D.; Bernhard, J.; Beckmann, C. Fatigue and fracture of weldments - The IBESS approach for the determination of the fatigue life and strength of weldments by fracture mechanics analysis The acronym IBESS stands for "Integrale Bruchmechanische Ermittlung der Schwingfestigkeit von Schweißverbindungen" which, translated from German, means "integral fracture mechanics determination of the fatigue strength of welds". the method introduced in this study is the outcome of a German Research cluster in which eight partners were involved. A list of them is found at the end this study. The IBESS method is characterized by a number of partially novel aspects and elements of fracture mechanics applied to the evaluation of fatigue stength of welds. The most important ones are: (a) Determination of fatigue crack propagation for mechanically/physically short and long cracks. (b) Determination of an elastic-plastic crack driving force for the treatment of mechanically short cracks. To that purpose an analytical expression for the cyclic J-integral was developed and validated against finite element results. (c) The gradual build-up of the crack closure phenomenon is determined by using cyclic R-curves which describe the crack size dependency of the fatigue crack propagation threshold in the physically short crack growth regime. (d) A physically meaningful initial crack size is defined for total life consideration. It is based on a two-criteria approach. Based on a cyclic R-curve analysis, the crack size at crack arrest is determined as a lower bound. If, however, a pre-existing crack-like defect is larger than this, its dimensions define the initial crack size. (e) Multiple crack propagation at the weld toe is considered. (f) In conjunction with this, the variation of the weld toe geometry is considered in a stochastic model. (g) As a result, both the fatigue limit (defined for 107 loading cycles) and the finite life (high cycle) fatigue S-N curve are obtained statistically. (h) At various analysis steps, parametric equations have been developed which allow for analytical calculations instead of complete stochastic analyses based on finite elements which are unrealistic even at present. (i) The method has been validated with a large number of S-N curves including two materials, three weldment types with two geometries, each referring to differnt manufacturing technologies and the as-welded and stressrelieved state. (j) Althrough not finally solved, an extended discussion is provided on the issue of welding residual stresses including their redistribution under cyclic loading. (k) A number of simplifications is proposed at lower analyses levels which, however, partly lack complete validation by now. Berlin Springer-Verlag 2019 978-3-03004-072-7 1 189 urn:nbn:de:kobv:b43-468853 2018-12-12 OPUS4-47576 Monographie Zerbst, Uwe; Madia, Mauro; Schork, B.; Hensel, J.; Kucharczyk, P.; Ngoula, D.; Tchuindjang, D.; Bernhard, J.; Beckmann, C. The IBESS approach for the determination of the fatigue life and strength of weldments by fracture mechanics analysis This book provides a comprehensive and thorough guide to those readers who are lost in the often-confusing context of weld fatigue. It presents straightforward information on the fracture mechanics and material background of weld fatigue, starting with fatigue crack initiation and short cracks, before moving on to long cracks, crack closure, crack growth and threshold, residual stress, stress concentration, the stress intensity factor, J-integral, multiple cracks, weld geometries and defects, microstructural parameters including HAZ, and cyclic stress-strain behavior. The book treats all of these essential and mutually interacting parameters using a unique form of analysis. Cham Springer 2019 Fatigue and Fracture of Weldments 978-3-030-04072-7 1 130 10.1007/978-3-030-04073-4 2019-03-20 OPUS4-16708 Zeitschriftenartikel Schartel, Bernhard; Braun, Ulrike; Balabanovich, Aliaksandr; Artner, J.; Ciesielski, M.; Döring, M.; Perez, R.M.; Sandler, J.K.W.; Altstädt, V. Pyrolysis and fire behaviour of epoxy systems containing a novel 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-(DOPO)-based diamino hardener Highly soluble 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-(DOPO)-based diamino hardener (2), bearing its amino groups directly on the DOPO framework, is investigated with respect to its use as a reactive flame retardant in thermosets. A mechanism for decomposition of the corresponding phosphorus-modified epoxy resin system based on a diglycidylether of bisphenol A DGEBA and 2 (DGEBA/2) is proposed and compared to the systems using DGEBA and 4,4'-diaminodiphenylsulfon (DGEBA/DDS) and to a similar system based on the structurally comparable non-reactive DOPO-based compound (DGEBA/DDS/1). Additive 1 changed the decomposition characteristics of the epoxy resin only slightly and phosphorus was released. Incorporating 2 induces two-step decomposition and most of the phosphorus remains in the residue. Furthermore, the fire behaviour of neat epoxy resin systems and a representative carbon fibre-reinforced composite based on DGEBA, DDS and 2 (DGEBA/DDS/2) were examined and compared to that of the analogous composite systems based on DGEBA/DDS and DGEBA/DDS/1. Based on different flame retardancy mechanisms both the reactive compound 2 and the additive compound 1 improve flammability (increase in LOI >13% and achieving V-1 behaviour) of the epoxy resin and composites. Under forced flaming only the flame inhibition of the additive compound 1 acts sufficiently. Lastly, the superior key mechanical properties of the epoxy resin and composite based on 2 are sketched. Oxford Elsevier 2008 European polymer journal 44 3 704 715 10.1016/j.eurpolymj.2008.01.017 2016-02-19 OPUS4-12650 Zeitschriftenartikel Braun, Ulrike; Knoll, Uta; Schartel, Bernhard; Hoffmann, T.; Pospiech, D.; Artner, J.; Ciesielski, M.; Döring, M.; Perez-Graterol, R.; Sandler, J.K.W.; Altstädt, V. Novel Phosphorus-Containing Poly(ether sulfone)s and Their Blends with an Epoxy Resin: Thermal Decomposition and Fire Retardancy 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. Weinheim Wiley-VCH Verl. 2006 Macromolecular chemistry and physics 207 16 1501 1514 10.1002/macp.200600182 2016-02-19 OPUS4-15071 Zeitschriftenartikel Perez, R.M.; Sandler, J.K.W.; Altstädt, V.; Hoffmann, T.; Pospiech, D.; Artner, J.; Ciesielski, M.; Döring, M.; Balabanovich, Aliaksandr; Knoll, Uta; Braun, Ulrike; Schartel, Bernhard Novel Phosphorus-containing Hardeners with Tailored Chemical Structures for Epoxy Resins: Synthesis and Cured Resin Properties 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. Hoboken, NJ Wiley InterScience 2007 Journal of applied polymer science 105 5 2744 2759 2016-02-19 OPUS4-15705 Zeitschriftenartikel Artner, J.; Ciesielski, M.; Ahlmann, M.; Walter, O.; Döring, M.; Perez, R.M.; Altstädt, V.; Sandler, J.K.W.; Schartel, Bernhard A novel and effective synthetic approach to 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) Derivatives Starting from trivalent 10-alkoxy-10H-9-oxa-10-phosphaphenanthrenes, a broad range of DOPO derivatives was synthesized via transesterification with aliphatic alcohols and subsequent Michaelis-Arbuzov rearrangement using catalytic amounts of p-toluenesulfonic acid methylester. Due to the considerable differences in the nature of the alcohols employed, several procedures for processing them are presented. Philadelphia, USA Taylor & Francis 2007 Phosphorus, Sulfur and Silicion 182 9 2131 2148 10.1080/10426500701407417 2016-02-19 OPUS4-17624 Zeitschriftenartikel Artner, J.; Ciesielski, M.; Walter, O.; Döring, M.; Perez, R.M.; Sandler, J.K.W.; Altstädt, V.; Schartel, Bernhard A novel DOPO-based diamine as hardener and flame retardant for epoxy resin systems 10-Ethyl-9-oxa-10-phosphaphenanthrene-10-oxide (1) can be nitrated using acetic anhydride and fuming nitric acid. The nitro group is reduced using palladium on charcoal and hydrogen. These reaction conditions are used for the synthesis of an analogous DOPO-based diaminic hardener (7). An evaluation of the curing behavior, mechanical properties and flammability of a neat resin made of DGEBA and 7 (DGEBA + 7) and of a carbon fiber-reinforced resin made of DGEBA, 4,4-diaminodiphenylsulfon (DDS) and 7 (DGEBA + DDS + 7) shows the potential of this hardener to lead to flame-retardant systems while keeping relevant properties on a high level; especially when compared to a similar system (DGEBA + DDS + 1). Weinheim Wiley-VCH Verl. 2008 Macromolecular materials and engineering 293 6 503 514 10.1002/mame.200700287 2016-02-19 OPUS4-17627 Beitrag zu einem Sammelband Perez, R.M.; Sandler, J.K.W.; Altstädt, V.; Hoffmann, T.; Pospiech, D.; Artner, J.; Ciesielski, M.; Döring, M.; Braun, Ulrike; Schartel, Bernhard Schartel, Bernhard Flame retardant epoxy resin system for liquid composite moulding applications Norderstedt Books on Demand GmbH FRPM 2007 Advances in the flame retardancy of polymeric materials 978-3-8334-8873-3 69 84 2016-02-19 OPUS4-14112 Zeitschriftenartikel Perez, R.M.; Sandler, J.K.W.; Altstädt, V.; Hoffmann, T.; Pospiech, D.; Artner, J.; Ciesielski, M.; Döring, M.; Balabanovich, Aliaksandr; Schartel, Bernhard Effective halogen-free flame retardancy for a monocomponent polyfunctional epoxy using an oligomeric organophosphorus compound 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. New York, USA Springer Science + Business Media B.V. 2006 Journal of materials science 41 24 8347 8351 10.1007/s10853-006-1079-3 2016-02-19 OPUS4-14054 Zeitschriftenartikel Braun, Ulrike; Balabanovich, Aliaksandr; Schartel, Bernhard; Knoll, Uta; Artner, J.; Ciesielski, M.; Döring, M.; Perez, R.; Sandler, J.K.W.; Altstädt, V.; Hoffmann, T.; Pospiech, D. Influence of the oxidation state of phosphorus on the decomposition and fire behaviour of flame-retarded epoxy resin composites 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. Berlin Springer 2006 Polymer 47 26 8495 8508 10.1016/j.polymer.2006.10.022 2016-02-19 OPUS4-14573 Zeitschriftenartikel Schartel, Bernhard; Balabanovich, Aliaksandr; Braun, Ulrike; Knoll, Uta; Artner, J.; Ciesielski, M.; Döring, M.; Perez, R.; Sandler, J.K.W.; Altstädt, V.; Hoffmann, T.; Pospiech, D. Pyrolysis of Epoxy Resins and Fire Behavior of Epoxy Resin Composites Flame-Retarded with 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide Additives 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. Hoboken, NJ Wiley InterScience 2007 Journal of applied polymer science 104 4 2260 2269 2016-02-19 OPUS4-38144 Beitrag zu einem Tagungsband Bienge, J.-E.; Illerhaus, Bernhard; Epperlein, J. Szallies, agrathaer GmbH, Isabell Blick in den Boden Computertomographische Untersuchungen in einer Studie zum vergleichenden Wurzelwachstum von Raps unter verschiedenen Bedingungen der Bodenbearbeitung. agrathaer GmbH, Eberswalder Straße 84, 15374 Müncheberg unter Mitarbeit des Leibniz-Zentrums für Agrarlandschaftsforschung (ZALF) e.V. Müncheberg und der Komturei Lietzen GmbH 2016 20 Jahre Praxisversuch Lietzen Ackerbau und Forschung auf dem Weg in die Zukunft Feldtag in der Komturei Lietzen 20 Jahre Praxisversuch Lietzen Ackerbau und Forschung auf dem Weg in die Zukunft Feldtag in der Komturei Lietzen Komturei Lietzen, Germany 19.5.2016 19.5.2016 28 29 2016-11-08 OPUS4-732 Zeitschriftenartikel Schartel, Bernhard; Kunze, Ralf; Hennecke, Manfred; Kettner, A.; Wendorff, J. H. On the thermal behaviour and thermo-oxidative stability of liquid crystalline triphenylene compounds Columnar discotic materials are considered for applications in the area of photoconductivity and light-emitting diodes. A major requirement is their stability at elevated temperatures and in the presence of oxygen. The thermal and thermo-oxidative behaviour of discotic triphenylene derivatives was investigated by us using various methods, in particular by chemiluminescence (CL), UV-vis absorption spectroscopy and in situ thermogravimetry-mass spectroscopy (TG-MS). Various degradation processes are described for increasing temperature, and their influences on functional properties are discussed. Chichester Wiley 1999 Advanced materials for optics and electronics 9 2 55 64 10.1002/(SICI)1099-0712(199903/04)9:2<55::AID-AMO366>3.3.CO;2-R 2016-02-19 OPUS4-731 Zeitschriftenartikel Schartel, Bernhard; Wendorff, J. H. Molecular composites for molecular reinforcement: A promising concept between success and failure The basic principles of molecular reinforcement and especially the specific approaches to obtain homogeneous composites with molecularly dispersed rigid rods are focused on and discussed. Brief overviews and successful examples of the available data covering the main characteristics are summarized. Hoboken, NY Wiley Society of Plastics Engineers 1999 Polymer engineering & science 39 1 128 151 2016-02-19 OPUS4-2780 Beitrag zu einem Sammelband Müller, Bernd R.; Lange, Axel; Harwardt, Michael; Hentschel, Manfred P.; Illerhaus, Bernhard; Goebbels, Jürgen; Bamberg, J.; Heutling, F. 3D Refraction Computed Tomography Applied to Metal Matrix Composites For the first time Metal Matrix Composites (MMC) have been investigated by 3D Computed Tomography combined with enhanced interface contrast due to X-ray refraction. X-ray refraction is a relatively new approach for the characterization of advanced materials. The related techniques of Refraction Topography and Refraction Computed Tomography have been developed and applied at our laboratory during the last decade to meet the actual demand for improved nondestructive characterization of high performance composites, ceramics and other low density materials and components. X-ray refraction occurs, when X-rays crosses interfaces of spherical or cylindrical shape (e.g. pores or fibres) in the same way as visible light is refracted by lenses. These X-ray optical effects can be observed at small scattering angles of few minutes of arc as the refractive index n of X-rays is nearly unity (n = 1 – 10-6). Due to the short X-ray wavelength of about 0.1 nm the technique determines the amount of inner surfaces and interfaces of nanometer dimensions. The technique is expected to solve many problems in understanding the meaning of micro and sub micro structures in materials science. With the results of the CT investigation, some questions could be clarified for a better understanding of fatigue failure mechanisms under cyclic loading conditions. The specimens for the test programme have been provided by MTU Aero Engines. They consist of a titanium matrix (Ti6242) reinforced by SiC fibres (SCS6). The investigations have been performed at the materials research station of BAM (BAMline) at the Synchrotron Facility BESSY in Berlin, Germany. Covina, Calif. SAMPE Society for the Advancement of Material and Process Engineering 2003 Materials and processing 0-938994-95-6 35th International SAMPE technical conference Dayton, OH, USA 2003-09-28 2003-10-02 2016-02-19 OPUS4-5486 Beitrag zu einem Sammelband Müller, Bernd R.; Lange, Axel; Harwardt, Michael; Hentschel, Manfred P.; Illerhaus, Bernhard; Goebbels, Jürgen; Bamberg, J.; Heutling, F. Micro Crack Characterization of Metal Matrix Composites by 3D-Refraction-Computed-Tomography Montreal International Committee for Non-Destructive Testing Canadian Institute for NDE 2004 16th World Conference on Nondestructive Testing 16th World Conference on Nondestructive Testing Montreal, Canada 2004-08-30 2004-09-03 9 pages 2016-02-19 OPUS4-7978 Zeitschriftenartikel Böttcher, Bernhard; Gollmer, W.; Odelga, J. Zur zerstörungsfreien Prüfung beheizbarer Beläge mit Infrarotverfahren Heidelberg Straßenbau, Chemie u. Technik Verl. 1974 Bitumen, Teere, Asphalte, Peche 25 9 364 367 2016-02-19 OPUS4-13703 Beitrag zu einem Tagungsband Müller, Bernd R.; Lange, Axel; Harwardt, Michael; Hentschel, Manfred P.; Illerhaus, Bernhard; Goebbels, Jürgen; Bamberg, J.; Heutling, F. X-Ray Refraction Topography and Computed Tomography for NDE of Lightweight Materials Berlin European Federation for Non-Destructive Testing Deutsche Gesellschaft für zerstörungsfreie Prüfung 2006 9th European Conference on NDT 3-931381-86-2 9th European Conference on NDT Berlin, Germany 2006-09-25 2006-09-29 1(?) 9(?) 2016-02-19 OPUS4-14376 Beitrag zu einem Tagungsband Müller, J.; Kiechle, H.; Ewert, Uwe; Rädel, Christoph; Redmer, Bernhard Mobile Computer Tomography for In-Service Inspection in Nuclear Power Plants Berlin European Federation for Non-Destructive Testing Deutsche Gesellschaft für zerstörungsfreie Prüfung 2006 9th European Conference on NDT 3-931381-86-2 9th European Conference on NDT Berlin, Germany 2006-09-25 2006-09-29 1(?) 6(?) 2016-02-19 OPUS4-5870 Zeitschriftenartikel Müller, Bernd R.; Lange, Axel; Harwardt, Michael; Hentschel, Manfred P.; Illerhaus, Bernhard; Goebbels, Jürgen; Bamberg, J.; Heutling, F. Refraction computed tomography - Application to metal matrix composites Erstmals wurden MMCs mit Hilfe der Interface-Kontrast verstärkenden Röntgen-Refraktions-Technik in Kombination mit der 3D-CT-Technik untersucht. Die Methode der Röntgen-Refraktions-Topography sowie der Röntgen-Refraktions-Tomography wurden in den letzten Jahren speziell für die zerstörungsfreie Charakterisierung von Leichtbau-Hochleistungs-Werkstoffen wie Verbund-Werkstoffen und Keramiken entwickelt. Die Technik basiert auf der Refraktion von Röntgenlicht an Grenzflächen zwischen Bereichen unterschiedlicher Elektronendichte wie z.B. Faser- und Matrix-Werkstoff. Auf Grund der kurzen Röntgen-Wellenlänge hat der Brechungsindex einen Wert dicht bei eins, sodass der Streuwinkel nur wenige Bogenminuten beträgt. Der Vorteil der kurzen Wellenlänge besteht jedoch darin, dass Poren und Risse detektiert werden können, deren Größe im Nanometerbereich liegen. Damit kann die Refraktions-Technik zum besseren Verständnis von Mikro- und Submikro-Strukturen in der Materialwissenschaft eingesetzt werden. Mit der hier vorgestellten Refraktions-CT wurden Ermüdungsmechanismen an MMCs, bestehend aus SiC-Faser verstärktem Titan (Ti6242) untersucht. Die Messungen wurden am Röntgen-Messplatz der BAM (BAMline) am Synchrotron-Speicherring-BESSY in Berlin Adlershof durchgeführt. München Carl Hanser Verlag Bundesanstalt für Materialforschung und -prüfung 2004 Materialprüfung = Materials testing 46 6 314 319 10.3139/120.100592 2016-02-19 OPUS4-21824 Beitrag zu einem Tagungsband Schulz-Forberg, Bernd; Zeisler, Peter; Droste, Bernhard; Kondratiev, A.; Kozlov, J.; Tichinov, N. Soviet-German cooperation in safety improvements of spent fuel transport casks The paper gives a survey of the Soviet (Russian) -German activities which started in 1988 with the objective of creating a long-term scientific-technical cooperation in the field of transport and storage casks for spent nuclear fuel. The first step, i.e., the step of informing each other about the state of development is done. The more complicated second phase with concerted common activities of both the Russian and German competent authorities and industrial enterprises is intended to start in the near future. International Atomic Energy Agency 1992 PATRAM ´92 - 10th International symposium on the packaging and transportation of radioactive materials (Proceedings) 1 PATRAM ´92 - 10th International symposium on the packaging and transportation of radioactive materials Yokohama, Japan 1992-09-13 1992-09-18 343 350 2016-02-19 OPUS4-30140 Beitrag zu einem Tagungsband Kumano, Y.; Droste, Bernhard; Hirose, M.; Harvey, J.; Reiche, I..; Wolff, Dietmar; McConnell, P.; Varley, K. Overview of the IAEA's joint working group on integrated safety case for dual purpose casks Omnipress Institute of Nuclear Materials Management (INMM) 2013 PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials (Proceedings) PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials San Francisco, CA, USA 2013-08-18 2013-08-23 1 9(?) 2016-02-20 OPUS4-56292 Zeitschriftenartikel Xu, C.; Battig, Alexander; Schartel, Bernhard; Siegel, R.; Senker, J.; von der Forst, I.; Unverzagt, C.; Agarwal, S.; Möglich, A.; Greiner, A. Investigation of the Thermal Stability of Proteinase K for the Melt Processing of Poly(L‑lactide) The enzymatic degradation of aliphatic polyesters offers unique opportunities for various use cases in materials science. Although evidently desirable, the implementation of enzymes in technical applications of polyesters is generally challenging due to the thermal lability of enzymes. To prospectively overcome this intrinsic limitation, we here explored the thermal stability of proteinase K at conditions applicable for polymer melt processing, given that this hydrolytic enzyme is well established for its ability to degrade poly(L-lactide) (PLLA). Using assorted spectroscopic methods and enzymatic assays, we investigated the effects of high temperatures on the structure and specific activity of proteinase K. Whereas in solution, irreversible unfolding occurred at temperatures above 75−80 °C, in the dry, bulk state, proteinase K withstood prolonged incubation at elevated temperatures. Unexpectedly little activity loss occurred during incubation at up to 130 °C, and intermediate levels of catalytic activity were preserved at up to 150 °C. The resistance of bulk proteinase K to thermal treatment was slightly enhanced by absorption into polyacrylamide (PAM) particles. Under these conditions, after 5 min at a temperature of 200 °C, which is required for the melt processing of PLLA, proteinase K was not completely denatured but retained around 2% enzymatic activity. Our findings reveal that the thermal processing of proteinase K in the dry state is principally feasible, but equally, they also identify needs and prospects for improvement. The experimental pipeline we establish for proteinase K analysis stands to benefit efforts directed to this end. More broadly, our work sheds light on enzymatically degradable polymers and the thermal processing of enzymes, which are of increasing economical and societal relevance. ACS Publications 2022 Biomacromolecules 23 11 4841 4850 10.1021/acs.biomac.2c01008 2022-11-16 OPUS4-54185 Zeitschriftenartikel Marti, J.; Schartel, Bernhard; Oñate, E. Simulation of the burning and dripping cables in fire using the particle finite element method The behavior of the cable jacket in fire characterized by the tendency to melt and drip constitutes a major source of fire hazard. The reason is that the melted material may convey the flame from one point to another, expanding fire and contributing to the fire load. In this article, the capability of a new computational strategy based on the particle finite element method for simulating a bench-scale cables burning test is analyzed. The use bench-scale test has been previously used to simulate the full-scale test described in EN 50399. As the air effect is neglected, a simple combustion model is included. The samples selected are two cables consisting of a copper core and differently flame retarded thermoplastic polyurethane sheets. The key modeling parameters were determined from different literature sources as well as experimentally. During the experiment, the specimen was burned under the test set-up condition recording the process and measuring the temperature evolution by means of three thermocouples. Next, the test was reproduced numerically and compared with a real fire test. The numerical results show that the particle finite element method can accurately predict the evolution of the temperature and the melting of the jacket. Sage 2022 Journal of Fire Sciences 40 1 3 25 10.1177/07349041211039752 2022-01-05 OPUS4-37270 Zeitschriftenartikel Färber, C.; Titschack, J.; Schönberg, Chr. H. L.; Ehrig, Karsten; Boos, K.; Illerhaus, Bernhard; Asgaard, U.; Bromley, R. G.; Freiwald, A.; Wisshak, M. Bahn, M.; Fennel, K.; Kesselmeier, J.; Naqvi, S. W. A. Long-term macrobioerosion in the Mediterranean Sea assessed by micro-computed tomography Biological erosion is a key process for the recycling of carbonate and the formation of calcareous sediments in the oceans. Experimental studies showed that bioerosion is subject to distinct temporal variability, but previous long-term studies were restricted to tropical waters. Here, we present results from a 14-year bioerosion experiment that was carried out along the rocky limestone coast of the island of Rhodes, Greece, in the Eastern Mediterranean Sea, in order to monitor the pace at which bioerosion affects carbonate substrate and the sequence of colonisation by bioeroding organisms. Internal macrobioerosion was visualised and quantified by micro-computed tomography and computer-algorithm-based segmentation procedures. Analysis of internal macrobioerosion traces revealed a dominance of bioeroding sponges producing eight types of characteristic Entobia cavity networks, which were matched to five different clionaid sponges by spicule identification in extracted tissue. The morphology of the entobians strongly varied depending on the species of the producing sponge, its ontogenetic stage, available space, and competition by other bioeroders. An early community developed during the first 5 years of exposure with initially very low macrobioerosion rates and was followed by an intermediate stage when sponges formed large and more diverse entobians and bioerosion rates in-creased. After 14 years, 30 % of the block volumes were occupied by boring sponges, yielding maximum bioerosion rates of 900 g m. Göttingen Copernicus Publications European Geoscience Union 2016 Biogeosciences Journal of European Geosciences Union 13 11 3461 3474 urn:nbn:de:kobv:b43-372709 10.5194/bg-13-3461-2016 http://creativecommons.org/licenses/by/3.0/de/deed.de 2016-09-05 OPUS4-18680 Beitrag zu einem Sammelband Müller, Bernd R.; Lange, Axel; Harwardt, Marco; Hentschel, Manfred P.; Illerhaus, Bernhard; Goebbels, Jürgen; Bamberg, J.; Heutling, F. Danny Van Hemelrijck, ; Igor Solodov, ; Anastasopoulos, Athanasios; Gerhard Busse, Synchrotron-Refraction-Computed-Tomography for NDT and characterisation of lightweight composite materials London, UK Taylor & Francis 2008 Emerging Technologies in Non-Destructive Testing 978-0-415-46476-5 4th International Conference of Emerging Technologies in Non-Destructive Testing (ETNDT 4) Stuttgart, Germany 2007-04-02 2007-04-04 217 221 2016-02-19 OPUS4-19897 Beitrag zu einem Sammelband Matthies, Klaus; Erhard, Anton; Ernst, h.; Hübschen, G.; Just, Tilman; Völz, Uwe; Wessels, J.; Boehm, Rainer; Gebhardt, W.; Mrasek, Heinz; Neumann, Eberhard; Redmer, Bernhard; Schmitz, V.; Thomas, Hans-Martin; Walte, F. Ultraschallprüfung von austenitischen Werkstoffen Berlin DVS-Verl. Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.v. (DGZfP) 2009 Ultraschallprüfung von austenitischen Werkstoffen 978-3-87155-988-4 1. Aufl. 1 464 2016-02-19 OPUS4-38622 Zeitschriftenartikel Hörold, Andreas; Schartel, Bernhard; Trappe, Volker; Korzen, Manfred; Bünker, J. Fire stability of glass-fibre sandwich panels: The influence of core materials and flame retardants Fire resistance has become a key property for structural lightweight sandwich components in aviation, shipping, railway vehicles, and construction. The development of future composite materials and components demands adequate test procedures for simultaneous application of compression and fully developed fire. Therefore an intermediate-scale approach (specimen size = 500 mm x 500 mm) is applied with compressive loads (up to 1 MN) and direct application of a burner to one side of the specimens, as established in aviation for severe burn-through tests. The influence of different core structures (polyvinylchloride foam, polyisocyanorate foam reinforced by stitched glass bridges, and balsa wood) was investigated for glass-fibre-reinforced sandwich specimens with and without flame retardants applied on the fabrics, in the matrix, and on surface for each specimen at the same time. Times to failure were increased up to a factor of 4. The intumescent coating prolongs the time to failure significantly. What is more, using the intrinsic potential of the front skin together with the core to protect a load bearing back skin in sandwich panels, the design of the core - here using the wood core - is the most promising approach. Elsevier 2017 Composite Structures 160 1310 1318 10.1016/j.compstruct.2016.11.027 2016-12-08 OPUS4-36641 Beitrag zu einem Tagungsband Illerhaus, Bernhard; Maenz, S.; Bischoff, S.; Bungartz, M.; Bossert, J.; Kunisch, E.; Kinne, R. Maenz, S. Micro computer tomography (μCT) set-up for long-term serial measurements, image evaluation, and subsequent compressive strength tests on frozen sheep vertebrae for osteoporosis research Injection of poly(methyl methacrylate) cements, one standard Treatment for osteoporotic vertebral body fractures, may lead to critical loads and subsequent fractures in adjacent vertebral bodies. Biodegradable calcium phosphate cements (CPC) with bioinductive growth factors may be an alternative, since they have a Young's modulus comparable to that of cancellous bone. Non-destructive tests with μCT and quantitative Image evaluation are used to assess new bone growth and material resorption following intravertebral injection of CPC. Immediate deep-freezing of excised bone prevents shrinkage or tissue disintegration and the samples have to be kept frozen for all following steps, including transport, μCT measurements, and subsequent biomechanical tests. Here we will report on a set-up to preserve the frozen state of the material and allow stable long-term serial μCT measurements. In addition, the image processing technique for the evaluation of bone growth and selected results on subsequently carried out compressive strength tests will be presented. Berlin DGZfP 2016 Proceedings of the WCNDT2016 BB 158 WCNDT2016 München, Germany 13.6.2016 17.6.2016 1 7 urn:nbn:de:kobv:b43-366410 http://creativecommons.org/licenses/by-nd/3.0/de/ 2016-06-24 OPUS4-43859 Zeitschriftenartikel Madia, Mauro; Schork, B.; Bernhard, J.; Kaffenberger, M. Multiple crack initiation and propagation in weldments under fatigue loading The work aims at addressing the modelling and implementation of criteria for multiple crack propagation, including interaction and coalescence, for a more reliable fracture mechanics-based prediction of stress-life curves for weldments. A large experimental work is presented in which micro-cracks have been made visible by heat-tinting at successive stages of fatigue life of the welded specimens. Here the correlation between the number of initiation sites and the applied stress level has been also investigated. The criteria have been implemented in in-house software, which allows multiple fatigue crack propagation, and validated against selected experimental tests. The results have shown that the modelling of multiple crack propagation and interaction is crucial for the prediction of the fatigue strength of weldments, both in finite and infinite life regime. Elsevier B.V. 2017 3rd International symposium on fatigue design and material defects (FDMD 2017) 7 FDMD 2017 Lecco, Italy 19.09.2017 22.09.2017 423 430 urn:nbn:de:kobv:b43-438593 10.1016/j.prostr.2017.11.108 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2018-01-22 OPUS4-51088 Zeitschriftenartikel Markwart, J. C.; Battig, Alexander; Urbaniak, T.; Haag, K.; Koschek, K.; Schartel, Bernhard; Wurm, F. R. Intrinsic flame retardant phosphonate-based vitrimers as a recyclable alternative for commodity polymers in composite materials Recycling of crosslinked fiber-reinforced polymers is difficult. Moreover, as they are often based on flammable resins, additional additives are needed. So-called "vitrimers" open the possibility of Recycling and reprocessing and repairing with dynamically crosslinked chemistries. To date, vitrimer-based composites still need flame retardant additives, such as organophosphates. An additive-free vitrimer composite has not been reported. Herein, we synthesized an intrinsic flame-retardant vitrimer, relying on vinylogous polyurethanes containing covalently installed phosphonates as flame-retardant units and prepared glassfiber-reinforced composites. We studied recycling and flame retardant properties and compared the data to phosphorus-free vitrimers and conventional epoxy resins (with and without additive flame retardant). Our phosphonate-based vitrimer proved in first tests, a flame retardant effect comparable to commercial flame retardant resins. The bending strength and bending modulus for the phosphorus-vitrimer glass fiber composites were comparable to glass fiber composites with permanently cross-linked epoxies. In summary, we were able to prove that the covalent installation of phosphonates into vitrimers allows the preparation of recyclable and intrinsic flame retardant composites that do not need flame retardant additives. We believe this concept can be expanded to other polymer networks and additives to generate recyclable and sustainable high-performance materials. 2020 Polymer Chemistry 11 30 4933 4941 urn:nbn:de:kobv:b43-510889 10.1039/d0py00275e https://creativecommons.org/licenses/by/4.0/deed.de 2020-08-10 OPUS4-35273 Zeitschriftenartikel Schartel, Bernhard; Perret, Birgit; Dittrich, Bettina; Ciesielski, M.; Krämer, J.; Müller, P.; Altstädt, V.; Zang, L.; Döring, M. Flame retardancy of polymers: the role of specific reactions in the condensed phase Condensed-phase mechanisms play a major role in fire-retardant polymers. Generations of development have followed the concept of charring to improve fire properties. Whereas the principal reactions are believed to be known, the specific description for multicomponent systems is lacking, as is the picture across different systems. A two-step approach is proposed in general, and also presented in greater detail. The second step covers the specific reactions controlling charring, whereas the actual reactants are provided in the preceding step. This model consistently incorporates the variety of structure–property relationships reported. A comprehensive case study is presented on seven phosphorus flame retardants in two epoxy resins to breathe life into the two-step approach. Weinheim Wiley-VCH Verl. 2016 Macromolecular materials and engineering 301 1 9 35 10.1002/mame.201500250 2016-02-20 OPUS4-48658 Zeitschriftenartikel Battig, Alexander; Markwart, J. C.; Wurm, F. R.; Schartel, Bernhard Hyperbranched phosphorus flame retardants: multifunctional additives for epoxy resins We successfully synthesized multifunctional P-based hyperbranched polymeric flame retardants (hb-FRs) with varying oxygen-to-nitrogen (O : N) content and characterized them via 1H and 31P NMR and GPC. Their miscibility in epoxy resins (EP) and impact on glass-transition temperatures (Tg) were determined via differential scanning calorimetry (DSC). Using thermogravimetric and evolved gas Analysis (TGA, TG-FTIR), pyrolysis gas chromatography/mass spectrometry (Py-GC-MS), hot stage FTIR, flammability tests UL-94 and LOI, fire testing via cone calorimetry, residue analysis via scanning electron microscopy (SEM) and elemental analysis, detailed decomposition mechanisms and modes of action are proposed. hb-polymeric FRs have improved miscibility and thermal stability, leading to high FR performance even at low loadings. Polymeric, complex FRs increase flame retardancy, mitigate negative effects of low molecular weight variants, and can compete with commercial aromatic FRs. The results illustrate the role played by the chemical structure in flame retardancy and highlight the potential of hb-FRs as multifunctional additives. RSC 2019 Polymer Chemistry 10 31 4346 4358 urn:nbn:de:kobv:b43-486589 10.1039/c9py00737g https://creativecommons.org/licenses/by/4.0/deed.de 2019-08-09 OPUS4-48559 Zeitschriftenartikel Lenz, J.; Pospiech, D.; Paven, M.; Albach, R. W.; Günther, Martin; Schartel, Bernhard; Voit, B. Improving the Flame Retardance of Polyisocyanurate Foams by Dibenzo[d,f][1,3,2]dioxaphosphepine 6-Oxide-Containing Additives A series of new flame retardants (FR) based on dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO) incorporating acrylates and benzoquinone were developed previously. In this study, we examine the fire behavior of the new flame retardants in polyisocyanurate (PIR) foams. The foam characteristics, thermal decomposition, and fire behavior are investigated. The fire properties of the foams containing BPPO-based derivatives were found to depend on the chemical structure of the substituents. We also compare our results to state-of-the-art non-halogenated FR such as triphenylphosphate and chemically similar phosphinate, i.e. 9,10-dihydro-9-oxa-10- phosphaphenanthrene-10-oxide (DOPO), based derivatives to discuss the role of the phosphorus oxidation state. MDPI 2019 Polymers 11 8 Article 1242 urn:nbn:de:kobv:b43-485590 10.3390/polym11081242 https://creativecommons.org/licenses/by/4.0/deed.de 2019-07-29 OPUS4-49453 Zeitschriftenartikel Markwart, J. C.; Battig, Alexander; Velencoso, M. M.; Pollok, D.; Schartel, Bernhard; Wurm, F. R. Aromatic vs. Aliphatic Hyperbranched Polyphosphoesters as Flame Retardants in Epoxy Resins The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, we present novel halogen-free aromatic and aliphatic hyperbranched polyphosphoesters (hbPPEs), which were synthesized by olefin Metathesis polymerization and investigated them as a FR in epoxy resins. We compare their efficiency (aliphatic vs. aromatic) and further assess the differences between the monomeric compounds and the hbPPEs. The decomposition and vaporizing behavior of a compound is an important factor in its flame-retardant behavior, but also the interaction with the pyrolyzing matrix has a significant influence on the performance. Therefore, the challenge in designing a FR is to optimize the chemical structure and its decomposition pathway to the matrix, with regards to time and temperature. This behavior becomes obvious in this study, and explains the superior gas phase activity of the aliphatic FRs. MDPI 2019 Molecules 24 21 3901 urn:nbn:de:kobv:b43-494535 10.3390/molecules24213901 https://creativecommons.org/licenses/by/4.0/deed.de 2019-10-31 OPUS4-49456 Zeitschriftenartikel Battig, Alexander; Markwart, J. C.; Wurm, F. R.; Schartel, Bernhard Matrix matters: Hyperbranched flame retardants in aliphatic and aromatic epoxy resins We synthesized a library of phosphorus-based flame retardants (phosphates and phosphoramides of low and high molar mass) and investigated their behavior in two epoxy resins (one aliphatic and one aromatic). The pyrolytic and burning behavior of the two resins (via TGA, TG-FTIR, Hot stage FTIR, Py-GC/MS, PCFC, DSC, LOI, UL-94, Cone calorimeter) are analyzed and compared to the results of flame retardant (FR)-containing composites. A decomposition pathway incorporating the identified modes of action and known chemical mechanisms is proposed. The overlap of decomposition temperature (Tdec) ranges of matrix and FR determines the efficacy of the system. Low molar mass FRs strongly impact material properties like Tg but are very reactive, and high molar mass variants are more thermally stable. Varying PeO and PeN content of the FR affects decomposition, but the chemical structure of the matrix also guides FR behavior. Thus, phosphates afford lower fire load and heat release in aliphatic epoxy resins, and phosphoramides can act as additives in an aromatic matrix or a reactive FRs in aliphatic ones. The chemical structure and the structure-property relationship of both FR and matrix are central to FR performance and must be viewed not as two separate but as one codependent system. Elsevier Ltd. 2019 Polymer Degradation and Stability 170 108986 10.1016/j.polymdegradstab.2019.108986 2019-10-31 OPUS4-49757 Zeitschriftenartikel Markwart, J. C.; Battig, Alexander; Kuckhoff, T.; Schartel, Bernhard; Wurm, F. R. First phosphorus AB2 monomer for flame-retardant hyperbranched polyphosphoesters: AB2vs. A2 + B3 Branched polymers are an important class of polymers with a high number of terminal groups, lower viscosity compared to their linear analogs and higher miscibility, which makes them especially interesting for flame retardant applications, where the flame retardants (FR) are blended with another polymer matrix. Hyperbranched polyphosphoesters (hbPPEs) are gaining more and more interest in the field of flame retardancy, as low molar mass FRs often have the disadvantage of blooming out or leaching, which is not desired in consumer products. Here, we present the first phosphorus-based AB2 monomer for the synthesis of hbPPEs and assess its flame-retardant performance in an epoxy resin compared to a hbPPE synthesized by an A2 + B3 approach. The hbPPE synthesized from an AB2 monomer exhibited a slightly higher performance compared to a similar hbPPE, which was prepared by A2 + B3 polyaddition, probably due to its higher phosphorus content. RSC 2019 Polymer Chemistry 10 43 5920 5930 urn:nbn:de:kobv:b43-497570 10.1039/c9py01156k https://creativecommons.org/licenses/by/4.0/deed.de 2019-11-27 OPUS4-50237 Zeitschriftenartikel Tan, Yi; Wachtendorf, Volker; Klack, Patrick; Kukofka, Tobias; Ruder, J.; Schartel, Bernhard Durability of the flame retardance of ethylene-vinyl acetate copolymer cables: Comparing different flame retardants exposed to different weathering conditions Scientific publications addressing the durability of the flame retardance of cables during their long-term application are rare and our understanding lacks. Three commercial flame retardants, aluminum hydroxide, aluminum diethyl phosphinate (AlPi-Et), and intumescent flame retardant based on ammonium polyphosphate, applied in ethylene-vinyl acetate copolymer (EVA) model cables, are investigated. Different artificial aging scenarios were applied: accelerated weathering (UV-irradiation/temperature/rain phases), humidity exposure (elevated temperature/humidity), and salt spray exposure. The deterioration of cables' surface and flame retardancy were monitored through imaging, color measurements, attenuated total reflectance Fourier transform infrared spectroscopy, and cone calorimeter investigations. Significant degradation of the materials' surface occurred. The flame retardant EVA cables are most sensitive to humidity exposure; the cable with AlPi-Et is the most sensitive to the artificial aging scenarios. Nevertheless, substantial flame retardance persisted after being subjected for 2000 h, which indicates that the equivalent influence of natural exposure is limited for several years, but less so for long-term use. Wiley 2020 Journal of Applied Polymer Science 137 1 47548 10.1002/APP.47548 2020-01-22 OPUS4-50238 Zeitschriftenartikel Battig, Alexander; Markwart, J. C.; Wurm, F. R.; Schartel, Bernhard Sulfur's role in the flame retardancy of thio-ether-linked hyperbranched polyphosphoesters in epoxy resins Hyperbranched polyphosphoesters are promising multifunctional flame retardants for epoxy resins. These polymers were prepared via thiol-ene polyaddition reactions. While key chemical transformations and modes of actions were elucidated, the role of sulfur in the chemical composition remains an open question. In this study, the FR-performance of a series of phosphorus-based flame retardant additives with and without sulfur (thioethers or sulfones) in their structure are compared. The successful synthesis of thio-ether or sulfone-containing variants is described and verified by 1H and 31P NMR, also FTIR and MALDI-TOF. A decomposition process is proposed from pyrolytic evolved gas analysis (TG-FTIR, Py-GC/MS), and flame retardancy effect on epoxy resins is investigated under pyrolytic conditions and via fire testing in the cone calorimeter. The presence of sulfur increased thermal stability of the flame retardants and introduced added condensed phase action. Likely, Sulfur radical generation plays a key role in the flame-retardant mode of action, and sulfones released incombustible SO2. The results highlight the multifunctionality of the hyperbranched polymer, which displays better fire performance than its low molar mass thio-ether analogue due to the presence of vinyl groups and higher stability than its monomer due to the presence of thio-ether groups. Elsevier Ltd. 2020 European Polymer Journal 122 109390 10.1016/j.eurpolymj.2019.109390 2020-01-22 OPUS4-51957 Zeitschriftenartikel Tan, Yi; Wachtendorf, Volker; Kukofka, Tobias; Klack, Patrick; Ruder, J.; Lin, Xuebao; Schartel, Bernhard Degradation of flame retardance: A comparison of ethylene-vinyl acetate and low-density polyethylene cables with two different metal hydroxides The durability of flame retardancy is a challenge for cables over long lifetimes. The degradation of flame retardance is investigated in two kinds of exposures, artificial weathering and humidity. In this basic study, typical mineral flame retardants in two polymers frequently used in cable jackets are investigated to get the fundamental picture. Aluminum hydroxide (ATH) and magnesium hydroxide (MDH) are compared in ethylene-vinyl acetate (EVA), and further in EVA and linear low-density polyethylene (LLDPE) cables containing the same ATH. The changes in chemical structure at the surface are studied through attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), the formation of cracks, and changes in color are investigated. The cone calorimeter and a bench scale fire testing cable module are utilized to evaluate the fire behavior of the cables. Although the flame retardancy deteriorated slightly, it survived harsh exposure conditions for 2000 h. Compared to EVA/MDH and LLDPE/ATH, the fire behavior of EVA/ATH is the least sensitive. Taken together, all of the results converge to estimate that there will be no problem with flame retardancy performance, for materials subjected to natural exposure for several years; the durability of fire retardancy is questionable for longer periods, and thus requires further investigation. Wiley 2021 Journal of Applied Polymer Science 138 14 50149 urn:nbn:de:kobv:b43-519573 10.1002/app.50149 https://creativecommons.org/licenses/by/4.0/deed.de 2021-01-06 OPUS4-51962 Buchkapitel Droste, Bernhard; Wolff, Dietmar; Bevilacqua, A.; Reiche, I.; Harvey, J.; Hirose, M.; Kumano, Y.; McConnell, P.; Saegusa, T.; Einziger, R. González-Espartero, A. Methodology for a Safety Case of a Dual Purpose Cask for Storage and Transport of Spent Fuel Spent nuclear fuel which is generated in the operation of nuclear reactors needs to be safely managed following its removal from the reactor core. On-site power reactor storage pools were designed on the assumption that after a short period of time spent nuclear fuel would be removed for reprocessing and disposal or further storage elsewhere. The amount of highly radioactive spent fuel that needs to be stored over longer periods of time is growing and additional storage capacity is required. One of the widely used options for additional storage capacity is the use of casks for dry storage of spent fuel. Among various existing dry storage concepts, several Member States are utilizing a concept of dual purpose casks (DPCs). This publication provides practical advice on the structure and contents of a DPC integrated safety case with reference to existing IAEA requirements relevant to the licensing and use of transport and storage casks for spent fuel. Vienna, Austria IAEA Publishing Section 2020 IAEA TECDOC SERIES 978-92-0-131620-2 1 109 2021-01-06 OPUS4-39443 Beitrag zu einem Tagungsband Matzen, Melissa; Marti, J. M.; Onate, E.; Idelsohn, S.; Schartel, Bernhard Particle finite element modelling and advanced experiments on dripping V-0 polypropylene Melt flow and dripping of polymeric materials can be both beneficial and detrimental during fire. It reduces flame spread and result in extinction, as mass and heat are removed from the actual pyrolysis zone. In contrast, melt flow and dripping can provide an additional ignition source, additional process of flame spread and has the potential to start a pool fire. In the vertical UL 94 test, a well adjusted dripping behaviour of flame retarded polypropylene (PP-FR) resulted in a non-flaming dripping V-0 classification. For the polymer samples and their drops collected in UL 94, the decomposition and viscosity was investigated. Particle finite element method (PFEM) was successfully used to simulate the material behaviour in the UL 94 test and increased the understanding of the complex behaviour of polymeric materials during fire. Bromley, UK Interscience Communication 2017 Conference Proccedings Fire and Materials 2017 Fire and Materials, 15th International Conference San Francisco, CA, USA 06.02.2017 08.02.2017 57 62 2017-03-22 OPUS4-40462 Zeitschriftenartikel Maenz, S.; Brinkmann, O.; Kunisch, E.; Horbert, V.; Gunella, F.; Bischoff, S.; Schubert, H.; Sachse, A.; Xin, L.; Günster, Jens; Illerhaus, Bernhard; Jandt, K. D.; Bossert, J.; Kinne, R. W.; Bungartz, M. Enhanced bone formation in sheep vertebral bodies after minimally invasive treatment with a novel, PLGA fiber-reinforced brushite cement. Injectable, brushite-forming calcium phosphate cements (CPC) show potential for bone replacement, but they exhibit low mechanical strength. This study tested a CPC reinforced with poly(l-lactide-co-glycolide) acid (PLGA) fibers in a minimally invasive, sheep lumbar vertebroplasty model. The study aimed to test the in vivo biocompatibility and osteogenic potential of a PLGA fiber-reinforced, brushite-forming CPC in a sheep large animal model. Elsevier Science direct Elsevier Inc 2017 The Spine Journal 17 5 709 719 10.1016/j.spinee.2016.11.006 2017-06-02 OPUS4-45700 Zeitschriftenartikel Velencoso, M. M.; Battig, Alexander; Markwart, J. C.; Schartel, Bernhard; Wurm, F. R. Molecular firefighting - How modern phosphorus chemistry can help solve the challenge of flame retardancy The ubiquity of polymeric materials in daily life Comes with an increased fire risk, and sustained research into efficient flame retardants is key to ensuring the safety of the populace and material goods from accidental fires. Phosphorus, a versatile and effective element for use in flame retardants, has the potential to supersede the halogenated variants that are still widely used today: current formulations employ a variety of modes of action and methods of implementation, as additives or as reactants, to solve the task of developing flameretarding polymeric materials. Phosphorus-based flame retardants can act in both the gas and condensed phase during a fire. This Review investigates how current phosphorus chemistry helps in reducing the flammability of polymers, and addresses the future of sustainable, efficient, and safe phosphorus-based flame-retardants from renewable sources. Wiley VHC 2018 Angewandte Chemie Int. Ed. 57 33 10450 10467 urn:nbn:de:kobv:b43-457009 10.1002/anie.201711735 https://creativecommons.org/licenses/by-nc/4.0/deed.de 2018-08-13 OPUS4-56771 Zeitschriftenartikel Lenz, J. U.; Pospiech, D.; Komber, H.; Korwitz, A.; Kobsch, O.; Paven, M.; Albach, R. W.; Günther, Martin; Schartel, Bernhard Effective halogen-free flame-retardant additives for crosslinked rigid polyisocyanurate foams: Comparison of chemical structures The impact of phosphorus-containing flame retardants (FR) on rigid polyisocyanurate (PIR) foams is studied by systematic variation of the chemical structure of the FR, including non-NCO-reactive and NCO-reactive dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO)- and 9,10 dihydro-9-oxa-10 phosphaphenanthrene-10-oxide (DOPO)-containing compounds, among them a number of compounds not reported so far. These PIR foams are compared with PIR foams without FR and with standard FRs with respect to foam properties, thermal decomposition, and fire behavior. Although BPPO and DOPO differ by just one oxygen atom, the impact on the FR properties is very significant: when the FR is a filler or a dangling (dead) end in the PIR polymer network, DOPO is more effective than BPPO. When the FR is a subunit of a diol and it is fully incorporated in the PIR network, BPPO delivers superior results. Basel MDPI 2023 Materials 16 1 1 22 urn:nbn:de:kobv:b43-567712 10.3390/ma16010172 https://creativecommons.org/licenses/by/4.0/deed.de 2023-01-04 OPUS4-56907 Zeitschriftenartikel Kinne, R. W.; Gunnella, F.; Kunisch, E.; Heinemann, S.; Nies, B.; Maenz, S.; Horbert, V.; Illerhaus, Bernhard; Huber, R.; Firkowska-Boden, I.; Bossert, J.; Jandt, K. D.; Sachse, A.; Bungartz, M.; Brinkmann, O. Performance of calcium phosphate cements in the augmentation of sheep vertebrae - An ex vivo study Oil-based calcium phosphate cement (Paste-CPC) shows not only prolonged shelf life and injection times, but also improved cohesion and reproducibility during application, while retaining the advantages of fast setting, mechanical strength, and biocompatibility. In addition, poly(L-lactideco-glycolide) (PLGA) fiber reinforcement may decrease the risk for local extrusion. Bone defects (diameter 5 mm; depth 15 mm) generated ex vivo in lumbar (L) spines of female Merino sheep (2-4 years) were augmented using: (i) water-based CPC with 10% PLGA fiber reinforcement (L3); (ii) Paste-CPC (L4); or (iii) clinically established polymethylmethacrylate (PMMA) bone cement (L5). Untouched (L1) and empty vertebrae (L2) served as controls. Cement performance was analyzed using micro-computed tomography, histology, and biomechanical testing. Extrusion was comparable for Paste-CPC(-PLGA) and PMMA, but significantly lower for CPC + PLGA. Compressive strength and Young's modulus were similar for Paste-CPC and PMMA, but significantly higher compared to those for empty defects and/or CPC + PLGA. Expectedly, all experimental groups showed significantly or numerically lower compressive strength and Young's modulus than those of untouched controls. Ready-to-use Paste-CPC demonstrates a performance similar to that of PMMA, but improved biomechanics compared to those of water-based CPC + PLGA, expanding the therapeutic arsenal for bone defects. O, significantly lower extrusion of CPC + PLGA fibers into adjacent lumbar spongiosa may help to reduce the risk of local extrusion in spinal surgery. Basel MDPI 2021 Materials 14 14 1 12 urn:nbn:de:kobv:b43-569072 10.3390/ma14143873 https://creativecommons.org/licenses/by/4.0/deed.de 2023-01-26 OPUS4-58601 Zeitschriftenartikel Turski Silva Diniz, Analice; Marti, J. M.; Schartel, Bernhard High Heat Resistance Can Be Deceiving: Dripping Behavior of Polyamide 4.6 in Fire Polyamide 4.6 (PA46) is a high-heat-resistant polymer, but it has no dripping resistance under fire. Three commercial grades of PA46 are investigated under UL 94 vertical fire test conditions. Their performances are discussed based on the materials' structural, thermal, and rheological properties. PA46 presents flaming drops, whereas dripping is prevented in the flame-retarded PA46. Friction-modified PA46 has increased flaming dripping. Temperature profiles of the specimens under fire and the temperature of the drops are measured by thermocouples. A UL 94 vertical test configuration consisting of two flame applications is designed to assess the quantitative dripping behavior of the set of materials by the particle finite element method (PFEM). Polymer properties (activation energy and Arrhenius coefficient of decomposition, char yield, density, effective heat of combustion, heat of decomposition, specific heat capacity, and thermal conductivity) in addition to rheological responses in high temperatures are estimated and measured as input parameters for the simulations. The dripping behavior obtained by simulated materials corresponds with the experimental results in terms of time and drop size. A consistent picture of the interplay of the different phenomena controlling dripping under fire appears to deliver a better understanding of the role of different materials' properties Wiley-VCH 2023 Macromolecular Mater and Engineering 308 10 1 11 urn:nbn:de:kobv:b43-586015 10.1002/mame.202300091 https://creativecommons.org/licenses/by/4.0/deed.de 2023-10-18 OPUS4-59076 Zeitschriftenartikel Fornacon-Wood, C.; Stühler, M. R.; Gallizioli, C.; Manjunatha, B. R.; Wachtendorf, Volker; Schartel, Bernhard; Plajer, A. J. Precise construction of weather-sensitive poly(ester-alt-thioesters) from phthalic thioanhydride and oxetane We report the selective ring opening copolymerisation (ROCOP) of oxetane and phthalic thioanhydride by a heterobimetallic Cr(III)K catalyst precisely yielding semi-crystalline alternating poly(esteralt- thioesters) which show improved degradability due to the thioester links in the polymer backbone. RSC 2023 Chemical Communications 59 76 11353 11356 urn:nbn:de:kobv:b43-590762 10.1039/d3cc03315e https://creativecommons.org/licenses/by/4.0/deed.de 2023-12-07 OPUS4-7039 Zeitschriftenartikel Mironov, Y.V.; Shestopalov, M.A.; Brylev, K.A.; Yarovoi, S. S.; Romanenko, G.V.; Fedorov, V.E.; Spies, H.; Pietzsch, H.-J.; Stephan, H.; Geipel, G.; Bernhard, G.; Kraus, Werner [Re6Q7O(3,5-Me2PzH)6]Br2.3,5-Me2PzH (Q = S, Se) - New Octahedral Rhenium Cluster Complexes with Organic Ligands: Original Synthetic Approach and Unexpected Ligand Exchange in the Cluster Core Weinheim Wiley-VCH Verl. 2005 European journal of inorganic chemistry 657 661 2016-02-19 OPUS4-17922 Zeitschriftenartikel Krause, Martin; Milmann, Boris; Mielentz, Frank; Streicher, Doreen; Redmer, Bernhard; Mayer, K.; Langenberg, K.-J.; Schickert, M. Ultrasonic Imaging Methods for Investigation of Post-tensioned Concrete Structures: A Study of Interfaces at Artificial Grouting Faults and Its Verification This paper presents the progress of successful location of grouting faults in tendon ducts with ultrasonic imaging. The examples were obtained in the research group FOR 384 funded by DFG (German Research Foundation). The co-operation of experimental research and modeling allowed imaging and identification of grouted and ungrouted areas of tendon ducts (including strands) in a large test specimen (40 m²). In addition to the criteria for indicating grouting faults in post-tensioned ducts known until now the phase evaluation of reflected ultrasonic pulses is described. Experiments and modeling of wave propagation are presented for reflections at metal plates in concrete (thickness range 0.5 mm to 40 mm) and for tendon ducts including strands. The main part of the progress was achieved by automated measurements using dry contact transducers, 3D-SAFT reconstruction including phase evaluation and modeling considering wave propagation for typical elastic parameters and exact experimental site conditions. The results for shear waves as well as for pressure waves are compared in the frequency range from 50 kHz to 120 kHz. New York, NY Plenum Press 2008 Journal of nondestructive evaluation 27 1-3 67 82 10.1007/s10921-008-0033-5 2016-02-19 OPUS4-12641 Zeitschriftenartikel Perez, R.M.; Sandler, J.K.W.; Altstädt, V.; Hoffmann, T.; Pospiech, D.; Ciesielski, M.; Döring, M.; Braun, Ulrike; Knoll, Uta; Schartel, Bernhard Effective halogen-free flame retardants for carbon fibre-reinforced epoxy composites 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. New York, USA Springer Science + Business Media B.V. 2006 Journal of materials science 41 15 4981 4984 10.1007/s10853-006-0134-4 2016-02-19 OPUS4-14515 Zeitschriftenartikel Perez, R.M.; Sandler, J.K.W.; Altstädt, V.; Hoffmann, T.; Pospiech, D.; Ciesielski, M.; Döring, M.; Braun, Ulrike; Balabanovich, Aliaksandr; Schartel, Bernhard Novel phosphorus-modified polysulfone as a combined flame retardant and toughness modifier for epoxy resins 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. Berlin Springer 2007 Polymer 48 3 778 790 2016-02-19 OPUS4-14489 Zeitschriftenartikel Mironov, Y.V.; Brylev, K.A.; Shestopalov, M.A.; Yarovoi, S. S.; Fedorov, V.E.; Spies, H.; Pietzsch, H.-J.; Stephan, H.; Geipel, G.; Bernhard, G.; Kraus, Werner Octahedral rhenium cluster complexes with organic ligands: Synthesis, structure and properties of [Re6Q8(3,5-Me2PzH)6]Br2 . 2(3,5-Me2PzH) (Q = S, Se) Two new octahedral cluster complexes – [Re6S8(3,5-Me2PzH)6]Br2 · 2(3,5-Me2PzH) (1) and [Re6Se8(3,5-Me2PzH)6]Br2 · 2(3,5-Me2PzH) (2), where 3,5-Me2PzH is 3,5-dimethylpyrazole, have been synthesized using reaction of rhenium chalcobromide complexes Cs4[Re6S8Br6] · 2H2O and Cs3[Re6Se8Br6] · H2O, respectively, with molten 3,5-dimethylpyrazole. Both compounds synthesized were characterized by X-ray single-crystal diffraction and chemical analysis, IR and luminescent spectra. Lausanne Elsevier Sequoia 2006 Inorganica Chimica Acta 359 4 1129 1134 10.1016/j.ica.2005.08.012 2016-02-19 OPUS4-21670 Beitrag zu einem Sammelband Kempel, Florian; Schartel, Bernhard; Hofmann-Böllinghaus, Anja; Butler, K.M.; Onate, E.; Idelsohn, S.R.; Rossi, R.; Marti, J.M. Numerical simulation of polymeric materials in UL 94 test: Competition between gasification and melt flow/dripping London, UK Interscience Communications 2010 Interflam 2010 (Proceedings) 1 978-0-9541216-5-5 Interflam 2010 - 12th International conference Nottingham, UK 2010-07-05 2010-07-07 721 730 2016-02-19 OPUS4-34285 Zeitschriftenartikel Kempel, Florian; Schartel, Bernhard; Marti, J.M.; Butler, K.M.; Rossi, R.; Idelsohn, S.R.; Onate, E.; Hofmann-Böllinghaus, Anja Modelling the vertical UL 94 test: competition and collaboration between melt dripping, gasification and combustion An experimental and numerical investigation of the effect of bisphenol A bis(diphenyl phosphate) (BDP) and polytetrafluoroethylene (PTFE) on the fire behaviour of bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) in the vertical UL 94 scenario is presented. Four PC/ABS blends were discussed, which satisfy different UL 94 classifications due to the competing effects of gasification, charring, flame inhibition and melt flow/dripping. For numerical investigation, the particle finite element method (PFEM) is used. Its capability to model the complex fire behaviour of polymers in the UL 94 is analysed. The materials' properties are characterised, in particular the additives impact on the dripping behaviour during thermal exposure. BDP is an efficient plasticiser; adding PTFE prevents dripping by causing a flow limit. PFEM simulations reproduce the dripping and burning behaviour, in particular the competition between gasification and dripping. The thermal impact of both the burner and the flame is approximated taking into account flame inhibition, charring and effective heat of combustion. PFEM is a promising numerical tool for the investigation of the fire behaviour of polymers, particularly when large deformations are involved. Not only the principal phenomena but also the different UL 94 classifications and the extinction times are well predicted. London Heyden 2015 Fire and materials 39 6 570 584 10.1002/fam.2257 2016-02-20 OPUS4-46908 Zeitschriftenartikel Schartel, Bernhard; Humphrey, J.K.; Gibson, A.G.; Hörold, Andreas; Trappe, Volker; Gettwert, V. Assessing the structural integrity of carbon-fibre sandwich panels in fire: Bench-scale approach The fire resistance of lightweight sandwich panels (SW) with carbon fibre/epoxy skins and a poly(methacryl imide) (PMI) foam core is investigated in compression under direct application of a severe flame (heat flux=200 kW m−2). A bench-scale test procedure was used, with the sample held vertically. The epoxy decomposition temperature was quickly exceeded, with rapid flash-over and progressive core softening and decomposition. There is a change in failure mode depending on whether the load is greater or less than 50% of the unexposed failure load, or in other words if one or two skins carry the load. At high loads, failure involved both skins with a single clear linear separation across each face. There is an inflection in the failure time relationship in the ∼50% load region, corresponding to the time taken for heat to be transmitted to the rear face, along with a change in the rear skin failure mode from separation to the formation of a plastic hinge. The integrity of the carbon front face, even with the resin burnt out, and the low thermal diffusivity of the core, both play key roles in prolonging rear face integrity, something to be borne in mind for future panel design. Intumescent coatings prolong the period before failure occurs. The ratio of times to failure with and without protection is proposed as a measure of their effectiveness. Apart from insulation properties, their adhesion and stability under severe fire impact play a key role. Elsevier 2019 Composites Part B 164 82 89 10.1016/j.compositesb.2018.11.077 2018-12-06