@article{ZhuangHuangRabczuketal., author = {Zhuang, Xiaoying and Huang, Runqiu and Rabczuk, Timon and Liang, C.}, title = {A coupled thermo-hydro-mechanical model of jointed hard rock for compressed air energy storage}, series = {Mathematical Problems in Engineering}, journal = {Mathematical Problems in Engineering}, abstract = {A coupled thermo-hydro-mechanical model of jointed hard rock for compressed air energy storage}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhuangHuangLiangetal., author = {Zhuang, Xiaoying and Huang, Runqiu and Liang, Chao and Rabczuk, Timon}, title = {A coupled thermo-hydro-mechanical model of jointed hard rock for compressed air energy storage}, series = {Mathematical Problems in Engineering}, journal = {Mathematical Problems in Engineering}, doi = {10.1155/2014/179169}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170428-31726}, abstract = {Renewable energy resources such as wind and solar are intermittent, which causes instability when being connected to utility grid of electricity. Compressed air energy storage (CAES) provides an economic and technical viable solution to this problem by utilizing subsurface rock cavern to store the electricity generated by renewable energy in the form of compressed air. Though CAES has been used for over three decades, it is only restricted to salt rock or aquifers for air tightness reason. In this paper, the technical feasibility of utilizing hard rock for CAES is investigated by using a coupled thermo-hydro-mechanical (THM) modelling of nonisothermal gas flow. Governing equations are derived from the rules of energy balance, mass balance, and static equilibrium. Cyclic volumetric mass source and heat source models are applied to simulate the gas injection and production. Evaluation is carried out for intact rock and rock with discrete crack, respectively. In both cases, the heat and pressure losses using air mass control and supplementary air injection are compared.}, subject = {Energiespeicherung}, language = {en} } @article{ZhaoLuRabczuk, author = {Zhao, Jun-Hua and Lu, Lixin and Rabczuk, Timon}, title = {Binding energy and mechanical stability of single- and multi-walled carbon nanotube serpentines}, series = {The Journal of Chemical Physics}, journal = {The Journal of Chemical Physics}, doi = {10.1063/1.4878115}, abstract = {Binding energy and mechanical stability of single- and multi-walled carbon nanotube serpentines}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhaoKouJiangetal., author = {Zhao, Jun-Hua and Kou, Liangzhi and Jiang, Jin-Wu and Rabczuk, Timon}, title = {Tension-induced phase transition of single-layer molybdenum disulphide (MoS2) at low temperatures}, series = {Nanotechnology}, journal = {Nanotechnology}, doi = {10.1088/0957-4484/25/29/295701}, abstract = {Tension-induced phase transition of single-layer molybdenum disulphide (MoS2) at low temperatures}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhaoJiangJiaetal., author = {Zhao, Jun-Hua and Jiang, Jin-Wu and Jia, Yue and Guo, Wanlin and Rabczuk, Timon}, title = {A theoretical analysis of cohesive energy between carbon nanotubes, graphene and substrates}, series = {Carbon}, journal = {Carbon}, doi = {10.1016/j.carbon.2013.01.041}, pages = {108 -- 119}, abstract = {Explicit solutions for the cohesive energy between carbon nanotubes, graphene and substrates are obtained through continuum modeling of the van der Waals interaction between them. The dependence of the cohesive energy on their size, spacing and crossing angles is analyzed. Checking against full atom molecular dynamics calculations and available experimental results shows that the continuum solution has high accuracy. The equilibrium distances between the nanotubes, graphene and substrates with minimum cohesive energy are also provided explicitly. The obtained analytical solution should be of great help for understanding the interaction between the nanostructures and substrates, and designing composites and nanoelectromechanical systems.}, subject = {Angewandte Mathematik}, language = {en} } @phdthesis{Zhao, author = {Zhao, Jun-Hua}, title = {Multiscale modeling of nanodevices based on carbon nanotubes and polymers}, doi = {10.25643/bauhaus-universitaet.2107}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20140130-21078}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {175}, abstract = {This thesis concerns the physical and mechanical interactions on carbon nanotubes and polymers by multiscale modeling. CNTs have attracted considerable interests in view of their unique mechanical, electronic, thermal, optical and structural properties, which enable them to have many potential applications. Carbon nanotube exists in several structure forms, from individual single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) to carbon nanotube bundles and networks. The mechanical properties of SWCNTs and MWCNTs have been extensively studied by continuum modeling and molecular dynamics (MD) simulations in the past decade since the properties could be important in the CNT-based devices. CNT bundles and networks feature outstanding mechanical performance and hierarchical structures and network topologies, which have been taken as a potential saving-energy material. In the synthesis of nanocomposites, the formation of the CNT bundles and networks is a challenge to remain in understanding how to measure and predict the properties of such large systems. Therefore, a mesoscale method such as a coarse-grained (CG) method should be developed to study the nanomechanical characterization of CNT bundles and networks formation. In this thesis, the main contributions can be written as follows: (1) Explicit solutions for the cohesive energy between carbon nanotubes, graphene and substrates are obtained through continuum modeling of the van der Waals interaction between them. (2) The CG potentials of SWCNTs are established by a molecular mechanics model. (3) The binding energy between two parallel and crossing SWCNTs and MWCNTs is obtained by continuum modeling of the van der Waals interaction between them. Crystalline and amorphous polymers are increasingly used in modern industry as tructural materials due to its important mechanical and physical properties. For crystalline polyethylene (PE), despite its importance and the studies of available MD simulations and continuum models, the link between molecular and continuum descriptions of its mechanical properties is still not well established. For amorphous polymers, the chain length and temperature effect on their elastic and elastic-plastic properties has been reported based on the united-atom (UA) and CG MD imulations in our previous work. However, the effect of the CL and temperature on the failure behavior is not understood well yet. Especially, the failure behavior under shear has been scarcely reported in previous work. Therefore, understanding the molecular origins of macroscopic fracture behavior such as fracture energy is a fundamental scientific challenge. In this thesis, the main contributions can be written as follows: (1) An analytical molecular mechanics model is developed to obtain the size-dependent elastic properties of crystalline PE. (2) We show that the two molecular mechanics models, the stick-spiral and the beam models, predict considerably different mechanical properties of materials based on energy equivalence. The difference between the two models is independent of the materials. (3) The tensile and shear failure behavior dependence on chain length and temperature in amorphous polymers are scrutinized using molecular dynamics simulations. Finally, the influence of polymer wrapped two neighbouring SWNTs' dispersion on their load transfer is investigated by molecular dynamics (MD) simulations, in which the SWNTs' position, the polymer chain length and the temperature on the interaction force is systematically studied.}, subject = {Mehrskalenmodell}, language = {en} } @article{ZhaoJiangWangetal., author = {Zhao, Jiyun and Jiang, Jin-Wu and Wang, L. and Guo, Wanlin and Rabczuk, Timon}, title = {Coarse-grained potentials of single-walled carbon nanotubes}, series = {Journal of the Mechanics and Physics of Solids}, journal = {Journal of the Mechanics and Physics of Solids}, abstract = {Coarse-grained potentials of single-walled carbon nanotubes}, subject = {Angewandte Mathematik}, language = {en} } @article{ZhangZhuangMuthuetal., author = {Zhang, Yancheng and Zhuang, Xiaoying and Muthu, Jacob and Mabrouki, Tarek and Fontaine, Micha{\"e}l and Gong, Yadong and Rabczuk, Timon}, title = {Load transfer of graphene/carbon nanotube/polyethylene hybrid nanocomposite by molecular dynamics simulation}, series = {Composites Part B Engineering}, journal = {Composites Part B Engineering}, pages = {27 -- 33}, abstract = {Load transfer of graphene/carbon nanotube/polyethylene hybrid nanocomposite by molecular dynamics simulation}, subject = {Angewandte Mathematik}, language = {en} } @article{XuMourrainGalligoetal., author = {Xu, G. and Mourrain, B. and Galligo, A. and Rabczuk, Timon}, title = {High-quality construction of analysis-suitable trivariate NURBS solids by reparameterization methods}, series = {Computational Mechanics}, journal = {Computational Mechanics}, abstract = {High-quality construction of analysis-suitable trivariate NURBS solids by reparameterization methods}, subject = {Angewandte Mathematik}, language = {en} } @phdthesis{Wiedemeyer, author = {Wiedemeyer, Nina}, title = {Buchfalten: Material Technik Gef{\"u}ge der K{\"u}nstlerb{\"u}cher}, doi = {10.25643/bauhaus-universitaet.2333}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20141210-23337}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {215}, abstract = {B{\"u}cher werden nicht erst seit ihrer industriellen Produktion aus gefalzten Papierbogen zusammengesetzt - schon mittelalterliche Codices wurden aus gefalteten Pergamenth{\"a}uten konstruiert. Fokus dieser Studie {\"u}ber das Medium Buch ist daher die Kulturtechnik der Faltung. Anders als in der philosophischen Auseinandersetzung mit dem Begriff der Falte, ist die Buchfalte keine anti-lineare Figur, sondern ein operationales Falzscharnier, welches Anordnungen im Buchraum bestimmt und Ornamente hervorbringt. Mediengeschichtliche Fragestellungen sind auf Analysen von Buchmaterial und K{\"u}nstlerb{\"u}chern vom 19. Jahrhundert bis zur Gegenwart basiert. Mit den B{\"u}chern u.a. von Christian Boltanski, Hanne Darboven und Hans-Peter Feldmann werden Erkenntnisse {\"u}ber buchgeschichtliche Zusammenh{\"a}nge gewonnen und das K{\"u}nstlerbuch in eine Geschichte des Mediums Buch eingestellt.}, subject = {Buch; Buchkunst; Falte; Ornament; Papier}, language = {de} } @phdthesis{Wiedemeyer, author = {Wiedemeyer, Nina}, title = {Buchfalten: Material Technik Gef{\"u}ge der K{\"u}nstlerb{\"u}cher}, doi = {10.25643/bauhaus-universitaet.2252}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20140806-22527}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {215}, abstract = {B{\"u}cher werden nicht erst seit ihrer industriellen Produktion aus gefalzten Papierbogen zusammengesetzt - schon mittelalterliche Codices wurden aus gefalteten Pergamenth{\"a}uten konstruiert. Fokus dieser Studie {\"u}ber das Medium Buch ist daher die Kulturtechnik der Faltung. Anders als in der philosophischen Auseinandersetzung mit dem Begriff der Falte, ist die Buchfalte keine anti-lineare Figur, sondern ein operationales Falzscharnier, welches Anordnungen im Buchraum bestimmt und Ornamente hervorbringt. Mediengeschichtliche Fragestellungen sind auf Analysen von Buchmaterial und K{\"u}nstlerb{\"u}chern vom 19. Jahrhundert bis zur Gegenwart basiert. Mit den B{\"u}chern u.a. von Christian Boltanski, Hanne Darboven und Hans-Peter Feldmann werden Erkenntnisse {\"u}ber buchgeschichtliche Zusammenh{\"a}nge gewonnen und das K{\"u}nstlerbuch in eine Geschichte des Mediums Buch eingestellt.}, subject = {Papier}, language = {de} } @phdthesis{Wellnitz, author = {Wellnitz, Felix}, title = {BAUKLIMATISCHE ERT{\"U}CHTIGUNG UND NACHHALTIGE INSTANDSETZUNG DENKMALGESCH{\"U}TZTER VERWALTUNGSBAUTEN DER 1950er JAHRE AM BEISPIEL DER EHEMALIGEN BAYERISCHEN LANDESVERTRETUNG VON SEP RUF IN BONN}, doi = {10.25643/bauhaus-universitaet.2303}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20140919-23031}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {172}, abstract = {Viele Baudenkmale sind dem Konflikt aus baulichem Instandsetzungsbedarf f{\"u}r eine zeitgem{\"a}ße Nutzung und einer sich m{\"o}glicherweise daraus ergebenden Gef{\"a}hrdung der Denkmalsubstanz ausgesetzt. Gr{\"u}nde sind steigende Energiekosten f{\"u}r den Geb{\"a}udebetrieb, zeitgem{\"a}ße Anforderungen an Behaglichkeit und Arbeitsschutz, sowie die Vermeidung von Sch{\"a}den an der Substanz aufgrund baulicher M{\"a}ngel des konstruktiven W{\"a}rme- und Feuchteschutzes. Gleichzeitig gilt f{\"u}r viele Bauten aber auch die Notwendigkeit regelm{\"a}ßiger Nutzung und Bewirtschaftung, um den Erhalt {\"u}berhaupt zu sichern. Die energetische Ert{\"u}chtigung von Baudenkmalen scheitert in diesem Spannungsfeld oft am unl{\"o}sbaren Konflikt zwischen dem Erhalt der bauzeitlichen Substanz auf der einen und der notwendigen energetischen Optimierung der Geb{\"a}udeh{\"u}lle auf der anderen Seite. Zielsetzung dieser Fallstudie ist die beispielhafte Entwicklung einer bauklimatischen und denkmalgerechten Ert{\"u}chtigungsstrategie am Beispiel eines Verwaltungsgeb{\"a}udes der Nachkriegsmoderne als Beitrag zur L{\"o}sung dieses Konfliktes.}, subject = {Denkmalpflege}, language = {de} } @phdthesis{Walsdorf, author = {Walsdorf, Joern}, title = {M-Learning: Lernen im mobilen Kontext an Hochschulen}, doi = {10.25643/bauhaus-universitaet.2136}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20140304-21361}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {A fundamental characteristic of human beings is the desire to start learning at the moment of birth. The rather formal learning process that learners have to deal with in school, on vocational training or in university, is currently subject to fundamental changes. The increasing technologization, overall existing mobile devices, the ubiquitous access to digital information, and students being early adaptors of all these technological innovations require reactions on the part of the educational system. This study examines such a reaction: The use of mobile learning in higher education. Examining the subject m-learning first requires an investigation of the educational model e-learning. Many universities already established e-learning as one of their educational segments, providing a wide range of methods to support this kind of teaching. This study includes an empirical acceptance analysis regarding the general learning behavior of students and their approval of e-learning methods. A survey on the approval of m-learning supplements the results. Mobile learning is characterized by both the mobility of the communication devices and the users. Both factors lead to new correlations, demonstrate the potential of today's mobile devices and the probability to increase the learning performance. The dissertation addresses these correlations and the use of mobile devices in the context of m-learning. M-learning and the usage of mobile devices not only require a reflection from a technological point of view. In addition to the technical features of such mobile devices, the usability of their applications plays an important role, especially with regard to the limited display size. For the purpose of evaluating mobile apps and browser-based applications, various analytical methods are suitable. The concluding heuristic evaluation points out the vulnerability of an established m-learning application, reveals the need for improvement, and shows an approach to rectify the shortcoming.}, subject = {Mobile Learning}, language = {de} } @article{VoelskeGollubHagenetal., author = {V{\"o}lske, Michael and Gollub, Tim and Hagen, Matthias and Stein, Benno}, title = {A keyquery-based classification system for CORE}, series = {D-Lib Magazine}, journal = {D-Lib Magazine}, doi = {10.1045/november14-voelske}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170426-31662}, abstract = {We apply keyquery-based taxonomy composition to compute a classification system for the CORE dataset, a shared crawl of about 850,000 scientific papers. Keyquery-based taxonomy composition can be understood as a two-phase hierarchical document clustering technique that utilizes search queries as cluster labels: In a first phase, the document collection is indexed by a reference search engine, and the documents are tagged with the search queries they are relevant—for their so-called keyqueries. In a second phase, a hierarchical clustering is formed from the keyqueries within an iterative process. We use the explicit topic model ESA as document retrieval model in order to index the CORE dataset in the reference search engine. Under the ESA retrieval model, documents are represented as vectors of similarities to Wikipedia articles; a methodology proven to be advantageous for text categorization tasks. Our paper presents the generated taxonomy and reports on quantitative properties such as document coverage and processing requirements.}, subject = {Massendaten}, language = {en} } @article{VoelkerMaempelKornadt, author = {V{\"o}lker, Conrad and M{\"a}mpel, Silvio and Kornadt, Oliver}, title = {Measuring the human body's micro-climate using a thermal manikin}, series = {Indoor Air}, journal = {Indoor Air}, number = {24, 6}, doi = {10.25643/bauhaus-universitaet.3815}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181025-38153}, pages = {567 -- 579}, abstract = {The human body is surrounded by a micro-climate which results from its convective release of heat. In this study, the air temperature and flow velocity of this micro-climate were measured in a climate chamber at various room temperatures, using a thermal manikin simulating the heat release of the human being. Different techniques (Particle Streak Tracking, thermography, anemometry, and thermistors) were used for measurement and visualization. The manikin surface temperature was adjusted to the particular indoor climate based on simulations with a thermoregulation model (UCBerkeley Thermal Comfort Model). We found that generally, the micro-climate is thinner at the lower part of the torso, but expands going up. At the head, there is a relatively thick thermal layer, which results in an ascending plume above the head. However, the micro-climate shape strongly depends not only on the body segment, but also on boundary conditions: the higher the temperature difference between the surface temperature of the manikin and the air temperature, the faster the air flow in the micro-climate. Finally, convective heat transfer coefficients strongly increase with falling room temperature, while radiative heat transfer coefficients decrease. The type of body segment strongly influences the convective heat transfer coefficient, while only minimally influencing the radiative heat transfer coefficient.}, subject = {Raumklima}, language = {en} } @article{VuBacLahmerZhangetal., author = {Vu-Bac, N. and Lahmer, Tom and Zhang, Yancheng and Zhuang, Xiaoying and Rabczuk, Timon}, title = {Stochastic predictions of interfacial characteristic of polymeric nanocomposites (PNCs)}, series = {Composites Part B Engineering}, journal = {Composites Part B Engineering}, pages = {80 -- 95}, abstract = {Stochastic predictions of interfacial characteristic of polymeric nanocomposites (PNCs)}, subject = {Angewandte Mathematik}, language = {en} } @article{VuBacLahmerKeiteletal., author = {Vu-Bac, N. and Lahmer, Tom and Keitel, Holger and Zhao, Jun-Hua and Zhuang, Xiaoying and Rabczuk, Timon}, title = {Stochastic predictions of bulk properties of amorphous polyethylene based on molecular dynamics simulations}, series = {Mechanics of Materials}, journal = {Mechanics of Materials}, pages = {70 -- 84}, abstract = {Stochastic predictions of bulk properties of amorphous polyethylene based on molecular dynamics simulations}, subject = {Angewandte Mathematik}, language = {en} } @misc{Udrea, type = {Master Thesis}, author = {Udrea, Mihai-Andrei}, title = {Assessment of Data from Dynamic Bridge Monitoring}, doi = {10.25643/bauhaus-universitaet.2174}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20140429-21742}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {The focus of the thesis is to process measurements acquired from a continuous monitoring system at a railway bridge. Temperature, strain and ambient vibration records are analysed and two main directions of investigation are pursued. The first and the most demanding task is to develop processing routines able to extract modal parameters from ambient vibration measurements. For this purpose, reliable experimental models are achieved on the basis of a stochastic system identification(SSI) procedure. A fully automated algorithm based on a three-stage clustering is implemented to perform a modal parameter estimation for every single measurement. After selecting a baseline of modal parameters, the evolution of eigenfrequencies is studied and correlated to environmental and operational factors. The second aspect deals with the structural response to passing trains. Corresponding triggered records of strain and temperature are processed and their assessment is accomplished using the average strains induced by each train as the reference parameter. Three influences due to speed, temperature and loads are distinguished and treated individually. An attempt to estimate the maximum response variation due to each factor is also carried out.}, subject = {Messtechnik}, language = {en} } @phdthesis{Torrado, author = {Torrado, Valentina}, title = {Die Pr{\"a}senz des Abjekten in der zeitgen{\"o}ssischen Kunstproduktion}, doi = {10.25643/bauhaus-universitaet.2129}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20140225-21297}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {115}, abstract = {Die Arbeit fokussiert die Rolle des Abjekten in der zeitgen{\"o}ssischen Kunst und hier insbesondere die Rolle der K{\"u}nstler aus den wohlhabenden - sogenannten postindustriellen - L{\"a}ndern. Die Arbeit mit abjekten Themen in der Kunstproduktion ist sehr pr{\"a}sent, jedoch aus einer anderen, eher individualistischen Perspektive. Die wichtigsten Orte der Kunst (Galerien, Museen, Kulturzentren) sind R{\"a}ume der Legitimation dieser Art von Produktion, dabei wird das Potential der Provokation hinterfragt. Die klassische Avantgarde, besonders der Dadaismus, hat das Abjekte zu Beginn des 20. Jahrhunderts als k{\"u}nstlerisches Material genutzt. Das Spiel mit Grenz{\"u}berschreitungen durch die Darstellung des Verbotenen und Ekelerregenden machte das Abjekte zur produktiven Kraft auch auf sozialer Ebene, weil es als Mittel dem gesellschaftlichen Protest und der sozialen Kritik diente.}, subject = {Abjekt}, language = {de} } @article{ThaiFerreiraBordasetal., author = {Thai, Chien H. and Ferreira, A.J.M. and Bordas, St{\´e}phane Pierre Alain and Rabczuk, Timon and Nguyen-Xuan, Hung}, title = {Isogeometric analysis of laminated composite and sandwich plates using a new inverse trigonometric shear deformation theory}, series = {European Journal of Mechanics}, journal = {European Journal of Mechanics}, pages = {89 -- 108}, abstract = {Isogeometric analysis of laminated composite and sandwich plates using a new inverse trigonometric shear deformation theory}, subject = {Angewandte Mathematik}, language = {en} }