TY - GEN A1 - Lehmann, Mario A1 - Martin, Frank A1 - Mannigel, Kerstin A1 - Kaltschmidt, Kristin A1 - Sack, Ulrich A1 - Anderer, Ursula T1 - Three-dimensional scaffold-free fusion culture: the way to enhanced chondrogenesis of in vitro propagated human articular chondrocytes T2 - European Journal of Histochemistry KW - in vitro cartilage KW - 3-D cell culture KW - fusion culture technique KW - tissue engineering KW - cell differentiation KW - extracellular matrix KW - immunohistochemistry Y1 - 2013 U6 - https://doi.org/10.4081/ejh.2013.e31 SN - 2038-8306 SN - 1121-760X VL - 57 IS - 4 SP - 205 EP - 215 ER - TY - GEN A1 - Martin, Frank A1 - Lehmann, Mario A1 - Schläger, Peter A1 - Sack, Ulrich A1 - Anderer, Ursula T1 - Differentiation capacity of chondrocytes in microtissues depends on TGF-ß subtyp T2 - Journal of biochips & tissue chips : JBTC KW - microtissues KW - differentiation of chondrocytes KW - TGF-β subtypes KW - BMP-7 Y1 - 2012 U6 - https://doi.org/10.4172/2153-0777.S2-002 SN - 2153-0777 N1 - Special Issue Article VL - S2 IS - 002 ER - TY - GEN A1 - Martin, Frank A1 - Lehmann, Mario A1 - Sack, Ulrich A1 - Anderer, Ursula T1 - In vitro development of personalized cartilage microtissues uncovers an individualized differentiation capacity of human chondrocytes T2 - Experimental Biology and Medicine KW - Articular cartilage KW - 3D culture KW - microtissue KW - scaffold-free KW - personalized differentiation KW - responder/non-responder KW - personalized diagnostic platform Y1 - 2017 U6 - https://doi.org/10.1177/1535370217728498 SN - 1535-3702 VL - 242 IS - 18 SP - 1746 EP - 1756 ER - TY - CHAP A1 - Martin, Frank A1 - Lehmann, Mario A1 - Anderer, Ursula ED - Daskalaki, Adriani T1 - Generation of scaffold free 3-D cartilage-like microtissues from human chondrocytes T2 - Medical Advancements in Aging and Regenerative Technologies: Clinical Tools and Applications KW - Cartilage Repair Strategies KW - Engineering cartilage-like microtissues without scaffolds KW - Redifferentiation of chondrocytes in a three-dimensional environment KW - S100 protein as marker for chondrogenic development Y1 - 2013 SN - 978-1-4666-2506-8 SP - 169 EP - 194 PB - IGI Global CY - Hershey, PA, USA ER - TY - GEN A1 - Berg, Heinz Peter A1 - Himmelberg, Axel A1 - Lehmann, Mario A1 - Dückershoff, Roland A1 - Neumann, Mathias T1 - The Turbo-Fuel-Cell 1.0 – family concept - Compact Micro Gas Turbine (MGT) – Solid Oxide Fuel Cell (SOFC) energy converters in the 100 - 500 kW electrical power range for the future T2 - IOP conference series : Materials Science and Engineering N2 - The “Turbo-Fuel-Cell-Technology” has been described as a MGT-SOFC hybrid system consisting of a recuperated micro gas turbine (MGT) process with an embedded solid oxide fuel cell (SOFC) subsystem. SOFC stacks are connected to “SOFC stack grapes” and are equipped with the so called HEXAR-Module. This module is composed of a high-temperature heat exchanger (HEX), an afterburner (A) and a steam reformer (R). The MGT-concept is based on a generator driven directly by the turbomachine and a recuperator, which returns the exhaust heat to the pressurized compressor outlet air. This provides the necessary base for a highly effective, pure MGT process and the “MGT-SOFC-high-efficiency process”. This paper describes the concept and the thermodynamic background of a highly effective and compact design of the “Turbo-Fuel-Cell 1.0-Family” in the electrical performance class from 100 to 500kW. The technological state of the system is shown and a rating of the system with comparative parameters is discussed. It becomes visible that all necessary basic technologies should be available and that the technology (for stationary applications) can have the “entry into services (E.I.S.)” in the next 10 years. The MGT-SOFC performance map under different operation conditions is discussed. This article also provides an overview of the research on MGT-SOFC-Systems and the scenario of an energy supply network and a mobile energy conversion of the future introduction. KW - MGT-SOFC KW - Brennstoffzellen KW - Mikrogasturbinen KW - Hybrid Y1 - 2018 UR - http://iopscience.iop.org/article/10.1088/1757-899X/297/1/012004 U6 - https://doi.org/doi:10.1088/1757-899X/297/1/012004 SN - 1757-899X VL - 297 ER - TY - GEN A1 - Berg, Heinz Peter A1 - Kleissl, Marko A1 - Himmelberg, Axel A1 - Lehmann, Mario A1 - Prechavut, Nontavut A1 - Vorpahl, Michael ED - Prukvilailert, Monchai T1 - Heat balancing of direct reforming fuel cells in MGT-SOFC hybrid systems T2 - 9th Thai Society of Mechanical Engineers, International Conference on Mechanical Engineering (TSME-ICoME 2018) 11–14 December 2018, Phuket, Thailand N2 - Solid oxide fuel cells convert chemical energy in electrical energy and are highly suitable for the conversion of hydrocarbon based fuels and products from PowerToGas conversions. Embedded in a micro gas turbine-cycle instead of the combustion chamber the heat energy of the injected fuel, released in the SOFC-Stack, can additionally converted into work and by a turbine-generator into electricity. In a compact system, SOFC stacks are designed to realize a direct steam-reforming process inside. In such direct-reforming fuel cell systems the SOFC operating temperature due to the heat demand for reforming, can be reduced to a value in the range of the outlet temperature of the downstream flow (650°C). If the cycle uses a recuperating system, the operating conditions of the SOFC can be realized without additional high-temperature heat exchanger systems. The system with an uncooled turbine, described in [1], just can reach the operating temperature with an additional high-temperature heat exchange. The system described in this publication does not require an additional high-temperature heat exchanger, because the X-value, as the ratio between the exchanged heat quantity and the required amount of heat to complete the MGT-cycle [2] due to the referring process, is nearly zero and can be realized via the inner container wall (of the MLC). The cycle is completed (between the SOFC and the turbine entry) by the heat input of an afterburner. Here the unreacted fuel of the SOFC fuel-stream is used to provide the necessary heat energy for the downstream turbo-generator-system. KW - MGT-SOFC KW - Heat balancing KW - simulation KW - thermodynamic cycle KW - effectivity Y1 - 2018 UR - https://iopscience.iop.org/article/10.1088/1757-899X/501/1/012007/meta U6 - https://doi.org/10.1088/1757-899X/501/1/012007 SN - 1757-899X SP - 50 EP - 60 PB - IOP Publishing/IOP Science CY - Bristol ET - 1. Auflage ER - TY - GEN A1 - Dückershoff, Roland A1 - Berg, Heinz Peter A1 - Himmelberg, Axel A1 - Lehmann, Mario A1 - Kleissl, Marko ED - Ashton, Anete T1 - Influence on the Electrical Efficiency of a Hybrid MGT-SOFC-System by μ-fogging in a-Two-Staged Compressor System T2 - IOP Conference Series: Materials Science and Engineering N2 - Hybrid combinations of solid oxide fuel cell and recuperated micro gas turbines can convert the chemical energy of hydrocarbon-based fuels in electrical energy with high electrical efficiency. With an integrated and improved cycle management, more than 70% of the energy content of the fuel could be converted. Therefore, the systems are highly suitable for the Power-To-Gas conversion. In particular, a pressure charging of the SOFC fuel cell leads to an increase in stack performance. By a downstream turbo set, after residual fuels are intentionally oxidized with an afterburner, additional electrical energy can be gained from the expansion of the hot exhaust gas stream and the overall efficiency can be increased. In order to increase the electrical efficiency of the system, it is proposed, to ensure the required compression of the process air in particular by a-two-staged turbo compressor with an intermediate cooling system. By thus achievable reduction of the dissipation of the compressor and by targeted condensation of finest drops in front of the second compressor stage affected by intermediate cooling, an increase in efficiency of the system is possible. This is achieved by targeted cooling of the process air behind a low pressure compression, so that it is saturated over 100% relative air humidity. As a result, a slightly supersaturated airflow is available for the second compressor stage, which enters the compressor after heat removal via an intermediate cooling having a small number of microdroplets. Therefore, the condensed water evaporates again by the heat of compression in the second stage and the compressed flow ultimately enters the recuperation at a lower temperature than during normal compression. Thus, more heat can be recovered within the recuperation system. Therefore, the electrical energy of the system can be produced having higher efficiency, because the heat dissipation of the overall system decreases. In this article it is presented, how such a process is thermodynamically modelled and how a technical realization can be built after optimization by simulations. Finally, in this study, the process-influencing factors are analyzed to show the highest possible electrical yield of such a system. KW - Micro Gasturbine, Hybrid, SOFC Fuel Cell, Fogging, Efficiency Y1 - 2020 UR - https://iopscience.iop.org/article/10.1088/1757-899X/886/1/012041 U6 - https://doi.org/10.1088/1757-899X/886/1/012041 SN - 1757-899X SP - 1 EP - 8 PB - IOP Science CY - Bristol ET - 1. Auflage ER - TY - CHAP A1 - Berg, Heinz Peter A1 - Dückershoff, Roland A1 - Lehmann, Mario A1 - Prechavut, Nontavut T1 - Micro Turbo-Fuel-Cell-Technology : Hybrid compact turbo machinery technology and thermodynamic aspects regarding design parameters of a high efficient MGT-SOFC-system T2 - 12th European Conference on Turbomachinery Fluid dynamics & Thermodynamics N2 - The improvement of decentralised energy supply systems has received an important role in the recent years. One option is the combination of SOFC with recuperated MGT. Here, a new strategy for selecting the system parameters, such as the operating temperature of the SOFC, turbine inlet temperature and the pressure ratio of the hybrid system, is presented. By introducing the heat ratio between the heat required to increase the process gas to the SOFC operating temperature and the heat required to raise the SOCF exhaust gas to the TIT, it was found that high efficiency (approx. 68%) is realisable in a compact hybrid system today. Analysis also shows that the HEX-technology is needed to improve the system effectiveness. Also, high recirculation rates with lower TIT can be considered as the future development direction. In addition, a sample configuration of an oil-free MGT rotor unit with high speed foil bearings is presented. KW - MGT-SOFC KW - Brennstoffzellen KW - Mikrogasturbinen KW - Hybrid Y1 - 2017 UR - http://www.euroturbo.eu/paper/ETC2017-266.pdf U6 - https://doi.org/10.29008/ETC2017-266 SP - 1 EP - 12 ER - TY - CHAP A1 - Lehmann, Mario A1 - Martin, Frank A1 - Scholka, Jenny A1 - Petto, Carola A1 - Wittenburg, Gretel A1 - Sack, Ulrich A1 - Anderer, Ursula T1 - Human chondrocytes and dental pulp stem cells enhance their chondrogenic differentiation potential via a two-step fusion culture technique T2 - Tissue Engineering, Part A, Vol. 21, Suppl. 1 KW - in vitro chondrogenesis KW - dental pulp stem cells KW - scaffold-free 3D culture KW - two-step fusion technique Y1 - 2015 U6 - https://doi.org/10.1089/ten.tea.2015.5000.abstracts SP - S-268 EP - S-269 ER - TY - CHAP A1 - Lehmann, Mario A1 - Voß, Fränzi A1 - Martin, Frank A1 - Schläger, Peter A1 - Anderer, Ursula T1 - Chondrogenic microtissues in the lab & for the clinic T2 - 3D cell culture 2016, book of abstracts, DECHEMA Biotechnologie KW - in vitro cartilage defect KW - in vitro therapy model KW - chondrocyte-derived cell line Y1 - 2016 SN - 978-3-89746-182-6 SP - 52 EP - 53 PB - DECHEMA e.V. CY - Frankfurt am Main ER -