@masterthesis{Nguyen, type = {Bachelor Thesis}, author = {Nguyen, Thai Cuong}, title = {Fl{\"a}chen zweiter Ordnung - D{\"a}cher m{\"u}ssen nicht eben sein}, doi = {10.25643/bauhaus-universitaet.3749}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181024-37496}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {47}, abstract = {In dieser Arbeit geht es um die Quadriken in der Ebene und im Raum. Dabei werden die Transformation in die Normalform und die Klassifikation untersucht. Aus den geometrischen Eigenschaften werden einige Anwendungsbeispiele der Quadriken in der Technik und dem allt{\"a}glichen Leben vorgestellt.}, subject = {Quadrik}, language = {de} } @article{FaizollahzadehArdabiliNajafiAlizamiretal., author = {Faizollahzadeh Ardabili, Sina and Najafi, Bahman and Alizamir, Meysam and Mosavi, Amir and Shamshirband, Shahaboddin and Rabczuk, Timon}, title = {Using SVM-RSM and ELM-RSM Approaches for Optimizing the Production Process of Methyl and Ethyl Esters}, series = {Energies}, journal = {Energies}, number = {11, 2889}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/en11112889}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181025-38170}, pages = {1 -- 20}, abstract = {The production of a desired product needs an effective use of the experimental model. The present study proposes an extreme learning machine (ELM) and a support vector machine (SVM) integrated with the response surface methodology (RSM) to solve the complexity in optimization and prediction of the ethyl ester and methyl ester production process. The novel hybrid models of ELM-RSM and ELM-SVM are further used as a case study to estimate the yield of methyl and ethyl esters through a trans-esterification process from waste cooking oil (WCO) based on American Society for Testing and Materials (ASTM) standards. The results of the prediction phase were also compared with artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS), which were recently developed by the second author of this study. Based on the results, an ELM with a correlation coefficient of 0.9815 and 0.9863 for methyl and ethyl esters, respectively, had a high estimation capability compared with that for SVM, ANNs, and ANFIS. Accordingly, the maximum production yield was obtained in the case of using ELM-RSM of 96.86\% for ethyl ester at a temperature of 68.48 °C, a catalyst value of 1.15 wt. \%, mixing intensity of 650.07 rpm, and an alcohol to oil molar ratio (A/O) of 5.77; for methyl ester, the production yield was 98.46\% at a temperature of 67.62 °C, a catalyst value of 1.1 wt. \%, mixing intensity of 709.42 rpm, and an A/O of 6.09. Therefore, ELM-RSM increased the production yield by 3.6\% for ethyl ester and 3.1\% for methyl ester, compared with those for the experimental data.}, subject = {Biodiesel}, language = {en} } @article{SirtlHadlichKrausetal., author = {Sirtl, Christin and Hadlich, Christiane and Kraus, Matthias and Osburg, Andrea}, title = {Determination of Bonding Failures in Transparent Materials with Non-Destructive Methods - Evaluation of Climatically Stressed Glued and Laminated Glass Compounds}, series = {World Journal of Engineering and Technology}, volume = {2018}, journal = {World Journal of Engineering and Technology}, number = {Vol. 6, No 2}, doi = {10.4236/wjet.2018.62020}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20180606-37526}, pages = {315 -- 331}, abstract = {As part of an international research project - funded by the European Union - capillary glasses for facades are being developed exploiting storage energy by means of fluids flowing through the capillaries. To meet highest visual demands, acrylate adhesives and EVA films are tested as possible bonding materials for the glass setup. Especially non-destructive methods (visual analysis, analysis of birefringent properties and computed tomographic data) are applied to evaluate failure patterns as well as the long-term behavior considering climatic influences. The experimental investigations are presented after different loading periods, providing information of failure developments. In addition, detailed information and scientific findings on the application of computed tomographic analyses are presented.}, subject = {Klebtechnik}, language = {en} } @phdthesis{Achenbach, author = {Achenbach, Marcus}, title = {Weiterentwicklung der Zonenmethode f{\"u}r den Nachweis der Feuerwiderstandsdauer von rechteckigen Stahlbetondruckgliedern}, publisher = {Bauhaus-Universit{\"a}tsverlag}, address = {Weimar}, isbn = {978-3-95773-264-4}, doi = {10.25643/bauhaus-universitaet.3848}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20190119-38484}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {174}, abstract = {Die Zonenmethode nach Hertz ist ein vereinfachtes Verfahren zur Heißbemessung von Stahlbetonbauteilen. Um eine h{\"a}ndische Bemessung zu erm{\"o}glichen, werden daher verschiedene Annahmen und Vereinfachungen getroffen. Insbesondere werden die thermischen Dehnungen vernachl{\"a}ssigt und das mechanische Verhalten durch einen verkleinerten Querschnitt mit konstanten Stoffeigenschaften beschrieben. Ziel der vorliegenden Arbeit ist, dieses vereinfachte Verfahren in ein nichtlineares Verfahren zur Heißbemessung von Stahlbetondruckgliedern bei Brandbeanspruchung durch die Einheits-Temperaturzeitkurve zu {\"u}berf{\"u}hren. Dazu werden die wesentlichen Annahmen der Zonenmethode {\"u}berpr{\"u}ft und ein Vorschlag zur Weiterentwicklung vorgestellt. Dieser beruht im Wesentlichen auf der Modellierung der druckbeanspruchten Bewehrung. Diese weiterentwickelte Zonenmethode wird durch die Nachrechnung von Laborversuchen validiert und das Sicherheitsniveau durch eine vollprobabilistische Analyse und den Vergleich mit dem allgemeinen Verfahren bestimmt.}, subject = {Bautechnik}, language = {de} } @phdthesis{Shakir, author = {Shakir, Masooma Mohib}, title = {Reconstructing the Sufi Shrine as a Living Heritage: Case of the Shrine of Shah Abdul Latif Bhitai, Sindh, Pakistan}, doi = {10.25643/bauhaus-universitaet.3770}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20180719-37708}, school = {Bauhaus-Universit{\"a}t Weimar}, abstract = {Living heritage sites are strongly connected to their historical, geographical, socio-political and cultural context. A descriptive narrative of the evolutionary process of the living heritage site of a Sufi shrine is undertaken in this research. It focuses on the changing relationship between the spatial and socio-cultural aspects over time. The larger or macro regional context is interrelated to the micro architectural context. The tangible heritage is defined by and intimately tied to the intangible aspects of the heritage. It is these constituting macro and micro elements and their interrelationships particularly through space and architecture that the research thesis explores in its documentation and analysis. The Sufi shrine in the South Asian Pakistani context is representative of a larger culture in the precolonial era. It is an expression of an indigenous modernity, belonging to a certain time period, place and community. The Sufi shrine as a building type has evolved from the precolonial time period, particularly starting at the golden ages of the Muslim Empire in the world (9th - 12th century), through the colonial age when western modernity arrived until the current neoliberal paradigm within the post independence period. Continued and evolved use of space, ritualistic performances, multiple social groups using the site are various elements whose documentation and analysis can establish the essential co-relations that contribute to continuity of its historical living. Physical and social relation of the historic site to its immediate settlement context is also a significant element that preserves the socio-cultural context. The chosen case of the Shrine of Shah Abdul Latif Bhitai, situated in the small town of Bhitshah in the province of Sindh, Pakistan forms a unique example where the particular physical and socio-cultural environment forms the context within which the Sufi heritage lives and survives. It is well integrated within its context at multiple levels. What are these levels and how do the constituting elements integrate is a major subject of research? These form the background to defining some of the basic issues and questions addressed in this doctoral thesis. Given that living heritage sites are unique due to their particular association to the context, the case study method was used to gain deeper insight and understanding on the topic.}, subject = {Kulturerbe}, language = {en} } @unpublished{SteinerBourinetLahmer, author = {Steiner, Maria and Bourinet, Jean-Marc and Lahmer, Tom}, title = {An adaptive sampling method for global sensitivity analysis based on least-squares support vector regression}, doi = {10.25643/BAUHAUS-UNIVERSITAET.3832}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181218-38320}, pages = {1 -- 33}, abstract = {In the field of engineering, surrogate models are commonly used for approximating the behavior of a physical phenomenon in order to reduce the computational costs. Generally, a surrogate model is created based on a set of training data, where a typical method for the statistical design is the Latin hypercube sampling (LHS). Even though a space filling distribution of the training data is reached, the sampling process takes no information on the underlying behavior of the physical phenomenon into account and new data cannot be sampled in the same distribution if the approximation quality is not sufficient. Therefore, in this study we present a novel adaptive sampling method based on a specific surrogate model, the least-squares support vector regresson. The adaptive sampling method generates training data based on the uncertainty in local prognosis capabilities of the surrogate model - areas of higher uncertainty require more sample data. The approach offers a cost efficient calculation due to the properties of the least-squares support vector regression. The opportunities of the adaptive sampling method are proven in comparison with the LHS on different analytical examples. Furthermore, the adaptive sampling method is applied to the calculation of global sensitivity values according to Sobol, where it shows faster convergence than the LHS method. With the applications in this paper it is shown that the presented adaptive sampling method improves the estimation of global sensitivity values, hence reducing the overall computational costs visibly.}, subject = {Approximation}, language = {en} } @unpublished{RezakazemiMosaviShirazian, author = {Rezakazemi, Mashallah and Mosavi, Amir and Shirazian, Saeed}, title = {ANFIS pattern for molecular membranes separation optimization}, volume = {2018}, doi = {10.25643/BAUHAUS-UNIVERSITAET.3821}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181122-38212}, pages = {1 -- 20}, abstract = {In this work, molecular separation of aqueous-organic was simulated by using combined soft computing-mechanistic approaches. The considered separation system was a microporous membrane contactor for separation of benzoic acid from water by contacting with an organic phase containing extractor molecules. Indeed, extractive separation is carried out using membrane technology where complex of solute-organic is formed at the interface. The main focus was to develop a simulation methodology for prediction of concentration distribution of solute (benzoic acid) in the feed side of the membrane system, as the removal efficiency of the system is determined by concentration distribution of the solute in the feed channel. The pattern of Adaptive Neuro-Fuzzy Inference System (ANFIS) was optimized by finding the optimum membership function, learning percentage, and a number of rules. The ANFIS was trained using the extracted data from the CFD simulation of the membrane system. The comparisons between the predicted concentration distribution by ANFIS and CFD data revealed that the optimized ANFIS pattern can be used as a predictive tool for simulation of the process. The R2 of higher than 0.99 was obtained for the optimized ANFIS model. The main privilege of the developed methodology is its very low computational time for simulation of the system and can be used as a rigorous simulation tool for understanding and design of membrane-based systems. Highlights are, Molecular separation using microporous membranes. Developing hybrid model based on ANFIS-CFD for the separation process, Optimization of ANFIS structure for prediction of separation process}, subject = {Fluid}, language = {en} } @unpublished{KavrakovMorgenthal, author = {Kavrakov, Igor and Morgenthal, Guido}, title = {Aeroelastic analyses of bridges using a Pseudo-3D vortex method and velocity-based synthetic turbulence generation}, doi = {10.25643/bauhaus-universitaet.4086}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20200206-40864}, abstract = {The accurate representation of aerodynamic forces is essential for a safe, yet reasonable design of long-span bridges subjected to wind effects. In this paper, a novel extension of the Pseudo-three-dimensional Vortex Particle Method (Pseudo-3D VPM) is presented for Computational Fluid Dynamics (CFD) buffeting analysis of line-like structures. This extension entails an introduction of free-stream turbulent fluctuations, based on the velocity-based turbulence generation. The aerodynamic response of a long-span bridge is obtained by subjecting the 3D dynamic representation of the structure to correlated free-stream turbulence in two-dimensional (2D) fluid planes, which are positioned along the bridge deck. The span-wise correlation of the free-stream turbulence between the 2D fluid planes is established based on Taylor's hypothesis of frozen turbulence. Moreover, the application of the laminar Pseudo-3D VPM is extended to a multimode flutter analysis. Finally, the structural response from the Pseudo-3D flutter and buffeting analyses is verified with the response, computed using the semi-analytical linear unsteady model in the time-domain. Meaningful merits of the turbulent Pseudo-3D VPM with respect to the linear unsteady model are the consideration of the 2D aerodynamic nonlinearity, nonlinear fluid memory, vortex shedding and local non-stationary turbulence effects in the aerodynamic forces. The good agreement of the responses for the two models in the 3D analyses demonstrates the applicability of the Pseudo-3D VPM for aeroelastic analyses of line-like structures under turbulent and laminar free-stream conditions.}, subject = {Bridge}, language = {en} }