TY  - CHAP
A1  - Müller, Karsten
A1  - Fischer, B.
T1  - Objective condition assessment of sewer systems
T2  - Strategic asset management of water supply and wastewater infrastructures : invited papers from the 2nd IWA Leading Edge Conference on Strategic Asset Management (LESAM), Lisbon, October [17 - 19] 2007 / ed. by Helene Alegre and Maria do Céu Almeida
Y1  - 2009
SN  - 9781843391869
SP  - 521
EP  - 534
PB  - IWA Publ.
CY  - London
ER  - 
TY  - CHAP
A1  - Müller, Karsten
A1  - Hüben, Susanne
T1  - From rehabilitation strategy up to formation of lots : implementation of a computer-aided decision support system
T2  - 11th International Conference on Urban Drainage, Edinburgh, Scotland, UK, 31st August to 5th September 2008
Y1  - 2008
ER  - 
TY  - JOUR
A1  - Müller, Martin
A1  - Hirschfeld, Julian
A1  - Lambertz, Rita
A1  - Schulze Lohoff, Andreas
A1  - Lustfeld, Hans
A1  - Pfeifer, Heinz
A1  - Reißel, Martin
T1  - Validation of a novel method for detecting and stabilizing malfunctioning areas in fuel cell stacks
JF  - Journal of power sources
N2  - In this paper a setup for detecting malfunctioning areas of MEAs in fuel cell stacks is described. Malfunctioning areas generate electric cross currents inside bipolar plates. To exploit this we suggest bipolar plates consisting not of two but of three layers. The third one is a highly conducting layer and segmented such that the cross currents move along the segments to the surface of the stack where they can be measured by an inductive sensor. With this information a realistic model can be used to detect the malfunctioning area. Furthermore the third layer will prevent any current inhomogeneity of a malfunctioning cell to spread to neighbouring cells in the stack. In this work the results of measurements in a realistic cell setup will be compared with the results obtained in simulation studies with the same configuration. The basis for the comparison is the reliable characterisation of the electrical properties of the cell components and the implication of these results into the simulation model. The experimental studies will also show the limits in the maximum number of segments, which can be used for a reliable detection of cross currents.
Y1  - 2014
U6  - https://doi.org/10.1016/j.jpowsour.2014.08.045
SN  - 1873-2755 (E-Journal); 0378-7753 (Print)
VL  - 272
SP  - 225
EP  - 232
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Müller, Tim M.
A1  - Altherr, Lena
A1  - Ahola, Marja
A1  - Schabel, Samuel
A1  - Pelz, Peter F.
T1  - Optimizing pressure screen systems in paper recycling: optimal system layout, component selection and operation
N2  - Around 60% of the paper worldwide is made from recovered paper. Especially adhesive contaminants, so called stickies, reduce paper quality. To remove stickies but at the same time keep as many valuable fibers as possible, multi-stage screening systems with several interconnected pressure screens are used. When planning such systems, suitable screens have to be selected and their interconnection as well as operational parameters have to be defined considering multiple conflicting objectives. In this contribution, we present a Mixed-Integer Nonlinear Program to optimize system layout, component selection and operation to find a suitable trade-off between output quality and yield.
KW  - Mixed-integer nonlinear problem
KW  - MINLP
KW  - Process engineering
KW  - Paper recycling
KW  - Multi-criteria optimization
Y1  - 2018
SN  - 978-3-030-18499-5
U6  - https://doi.org/10.1007/978-3-030-18500-8_44
SP  - 355
EP  - 361
PB  - Springer
CY  - Cham
ER  - 
TY  - CHAP
A1  - Müller, Tim M.
A1  - Altherr, Lena
A1  - Ahola, Marja
A1  - Schabel, Samuel
A1  - Pelz, Peter F.
ED  - Rodrigues, H. C.
T1  - Multi-Criteria optimization of pressure screen systems in paper recycling – balancing quality, yield, energy consumption and system complexity
T2  - EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization
N2  - The paper industry is the industry with the third highest energy consumption in the European Union. Using recycled paper instead of fresh fibers for papermaking is less energy consuming and saves resources. However, adhesive contaminants in recycled paper are particularly problematic since they reduce the quality of the resulting paper-product. To remove as many contaminants and at the same time obtain as many valuable fibres as possible, fine screening systems, consisting of multiple interconnected pressure screens, are used. Choosing the best configuration is a non-trivial task: The screens can be interconnected in several ways, and suitable screen designs as well as operational parameters have to be selected. Additionally, one has to face conflicting objectives. In this paper, we present an approach for the multi-criteria optimization of pressure screen systems based on Mixed-Integer Nonlinear Programming. We specifically focus on a clear representation of the trade-off between different objectives.
Y1  - 2019
SN  - 978-3-319-97773-7
U6  - https://doi.org/10.1007/978-3-319-97773-7_105
N1  - EngOpt 2018 Proceedings of the 6th International Conference on Engineering Optimization. 17-19 September 2018. Lisboa, Portugal
PB  - Springer International Publishing
CY  - Basel
ER  - 
TY  - CHAP
A1  - Müller, Tim M.
A1  - Altherr, Lena
A1  - Leise, Philipp
A1  - Pelz, Peter F.
T1  - Optimization of pumping systems for buildings: Experimental validation of different degrees of model detail on a modular test rig
T2  - Operations Research Proceedings 2019
N2  - Successful optimization requires an appropriate model of the system under consideration. When selecting a suitable level of detail, one has to consider solution quality as well as the computational and implementation effort. In this paper, we present a MINLP for a pumping system for the drinking water supply of high-rise buildings. We investigate the influence of the granularity of the underlying physical models on the solution quality. Therefore, we model the system with a varying level of detail regarding the friction losses, and conduct an experimental validation of our model on a modular test rig. Furthermore, we investigate the computational effort and show that it can be reduced by the integration of domain-specific knowledge.
KW  - Experimental validation
KW  - MINLP
KW  - Engineering optimization
KW  - Water supply system
KW  - Network design
Y1  - 2020
SN  - 978-3-030-48438-5
U6  - https://doi.org/10.1007/978-3-030-48439-2_58
N1  - Annual International Conference of the German Operations Research Society (GOR), Dresden, Germany, September 4-6, 2019
SP  - 481
EP  - 488
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Müller, Tim M.
A1  - Leise, Philipp
A1  - Lorenz, Imke-Sophie
A1  - Altherr, Lena
A1  - Pelz, Peter F.
T1  - Optimization and validation of pumping system design and operation for water supply in high-rise buildings
JF  - Optimization and Engineering
N2  - The application of mathematical optimization methods for water supply system design and operation provides the capacity to increase the energy efficiency and to lower the investment costs considerably. We present a system approach for the optimal design and operation of pumping systems in real-world high-rise buildings that is based on the usage of mixed-integer nonlinear and mixed-integer linear modeling approaches. In addition, we consider different booster station topologies, i.e. parallel and series-parallel central booster stations as well as decentral booster stations. To confirm the validity of the underlying optimization models with real-world system behavior, we additionally present validation results based on experiments conducted on a modularly constructed pumping test rig. Within the models we consider layout and control decisions for different load scenarios, leading to a Deterministic Equivalent of a two-stage stochastic optimization program. We use a piecewise linearization as well as a piecewise relaxation of the pumps’ characteristics to derive mixed-integer linear models. Besides the solution with off-the-shelf solvers, we present a problem specific exact solving algorithm to improve the computation time. Focusing on the efficient exploration of the solution space, we divide the problem into smaller subproblems, which partly can be cut off in the solution process. Furthermore, we discuss the performance and applicability of the solution approaches for real buildings and analyze the technical aspects of the solutions from an engineer’s point of view, keeping in mind the economically important trade-off between investment and operation costs.
KW  - Technical Operations Research
KW  - MINLP
KW  - MILP
KW  - Experimental validation
KW  - Pumping systems
Y1  - 2020
U6  - https://doi.org/10.1007/s11081-020-09553-4
SN  - 1573-2924
VL  - 2021
IS  - 22
SP  - 643
EP  - 686
PB  - Springer
ER  - 
TY  - CHAP
A1  - Müller, Tim M.
A1  - Schmitt, Andreas
A1  - Leise, Philipp
A1  - Meck, Tobias
A1  - Altherr, Lena
A1  - Pelz, Peter F.
A1  - Pfetsch, Marc E.
T1  - Validation of an optimized resilient water supply system
T2  - Uncertainty in Mechanical Engineering
N2  - Component failures within water supply systems can lead to significant performance losses. One way to address these losses is the explicit anticipation of failures within the design process. We consider a water supply system for high-rise buildings, where pump failures are the most likely failure scenarios. We explicitly consider these failures within an early design stage which leads to a more resilient system, i.e., a system which is able to operate under a predefined number of arbitrary pump failures. We use a mathematical optimization approach to compute such a resilient design. This is based on a multi-stage model for topology optimization, which can be described by a system of nonlinear inequalities and integrality constraints. Such a model has to be both computationally tractable and to represent the real-world system accurately. We therefore validate the algorithmic solutions using experiments on a scaled test rig for high-rise buildings. The test rig allows for an arbitrary connection of pumps to reproduce scaled versions of booster station designs for high-rise buildings. We experimentally verify the applicability of the presented optimization model and that the proposed resilience properties are also fulfilled in real systems.
KW  - Optimization
KW  - Mixed-integer nonlinear programming
KW  - Water distribution system
KW  - Resilience
KW  - Validation
Y1  - 2021
SN  - 978-3-030-77255-0
SN  - 978-3-030-77256-7
U6  - https://doi.org/10.1007/978-3-030-77256-7_7
N1  - Proceedings of the 4th International Conference on Uncertainty in Mechanical Engineering (ICUME 2021), June 7–8, 2021
SP  - 70
EP  - 80
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Müller, Ulrike
A1  - Bongaerts, Johannes
A1  - Bovenberg, Roel
A1  - Jossek, Ralf
A1  - Krämer, Marco
A1  - Linnemann, J.
A1  - Müschen, S.
A1  - Ritterbecks, S.
A1  - Sprenger, G.
A1  - Wubbolts, Marcel
T1  - Metabolic engineering to produce fine chemicals in Escherichia coli
JF  - Mededelingen van de Faculteit Landbouwwetenschappen, Rijksuniversiteit Gent
Y1  - 2001
SN  - 0035-533x
VL  - 66 (3a)
SP  - 215
EP  - 217
ER  - 
TY  - JOUR
A1  - Müller, Wolfram
A1  - Jung, Alexander
A1  - Ahammer, Helmut
T1  - Advantages and problems of nonlinear methods applied to analyze physiological time signals: human balance control as an example
JF  - Scientific Reports
Y1  - 2017
SN  - 2045-2322
U6  - https://doi.org/10.1038/s41598-017-02665-5
VL  - 7
IS  - Article number 2464
SP  - 1
EP  - 11
PB  - Springer Nature
CY  - Cham
ER  - 
TY  - CHAP
A1  - Müller-Abdelrazeq, Sarah Luisa
A1  - Brauner, Philipp
A1  - Calero Valdez, André
A1  - Jansen, Ulrich
A1  - Platte, Laura
A1  - Schaar, Anne-Kathrin
A1  - Steuer-Dankert, Linda
A1  - Zachow, Sebastian
A1  - Schönefeld, Kathrin
A1  - Haberstroh, Max
A1  - Leicht-Scholten, Carmen
A1  - Ziefle, Martina
ED  - Pather, Shaun
T1  - Interdisciplinary cooperation management in research clusters: a review of twelve years.
T2  - Proceedings of the 15th International Conference on Intellectual Capital, Knowledge Management & Organisational Learning
N2  - As an interdisciplinary research network, the Cluster of Excellence “Integrative Production Technology for High-Wage Countries” (CoE) comprises of around 150 researchers. Their scientific background ranges from mechanical engineering and computer science to social sciences such as sociology and psychology. In addition to content- and methodbased challenges, the CoE’s employees are faced with heterogenic organizational cultures, different hierarchical levels, an imbalanced gender distribution, and a high employee fluctuation. The sub-project Scientific Cooperation Engineering 1 (CSP1) addresses the challenge of interdisciplinary cooperation and organizational learning and aims at fostering interdisciplinarity and its synergies as a source of innovation. Therefore, the project examines means of reaching an organizational development, ranging from temporal structures to a sustainable network in production technology. To achieve this aim, a broad range of means has been developed during the last twelve years: In addition to physical measures such as regular network events and trainings, virtual measures such as the Terminology App were focused. The app is an algorithmic analysis method for uncovering latent topic structures of publications of the CoE to highlight thematic intersections and synergy potentials. The detection and promotion of has been a vital and long known element in knowledge management. Furthermore, CSP1 focusses on project management and thus developed evaluation tools to measure and control the success of interdisciplinary cooperation. In addition to the cooperation fostering measures, CSP1 conducted studies about interdisciplinarity and diversity and their relationship with innovation. The scientific background of these means and the research results of CSP1 are outlined in this paper to offer approaches for successful interdisciplinary cooperation management.
Y1  - 2018
SN  - 978-1-912764-09-9
N1  - hosted by University of the Western Cape, South Africa 29-30 November 2018
SP  - 216
EP  - 224
PB  - ACPIL
ER  - 
TY  - JOUR
A1  - Müller-Veggian, Mattea
T1  - Investigation of the preequilibrium reaction mechanism through the study of the isomer ratios ²¹¹,²¹² Po
JF  - Annual report 1979 / Kernforschungsanlage Jülich Institut für Kernphysik / Hrsg.: A. Fässler. - (Spezielle Berichte der Kernforschungsanlage Jülich ; 72)
Y1  - 1980
SP  - 32
PB  - Verlag des Forschungszentrums Jülich
CY  - Jülich
ER  - 
TY  - JOUR
A1  - Müller-Veggian, Mattea
T1  - High-spin level structure of ¹³³ La
JF  - Annual report 1981 / Kernforschungsanlage Jülich Institut für Kernphysik / Hrsg.: F. Grümmer. - (Spezielle Berichte der Kernforschungsanlage Jülich ; 146)
Y1  - 1982
SP  - 51
PB  - Kernforschungsanlage
CY  - Jülich
ER  - 
TY  - JOUR
A1  - Müller-Veggian, Mattea
A1  - Beuscher, H.
A1  - Bochev, B.
A1  - Haenni, D. R.
T1  - Study of reactions ²⁰⁹ Bi (a,charged particle Xn) At Ea= 45 Mev and 75 Mev
JF  - Frühjahrstagung ... des Fachausschusses Kernphysik und Hochenergiephysik der DPG (Sektion A: Kernphysik) / Deutsche Physikalische Gesellschaft (1980)
Y1  - 1980
N1  - Verhandlungen der Deutschen Physikalischen Gesellschaft ; 1980=6.R.15,8
SP  - 1088
ER  - 
TY  - JOUR
A1  - Müller-Veggian, Mattea
A1  - Beuscher, H.
A1  - Gono, Y.
T1  - High-spin states and isomers in light transitional nuclei around n=80
JF  - International Symposium on High-Spin States and Nuclear Structure : held at Dresden from 19-24. Sept. 1977 ; contributed papers / ed.: L. Funke ...
Y1  - 1977
N1  - International Symposium on High Spin States and Nuclear Structure <1977, Dresden> ; (ZfK / Zentralinstitut fuer Kernforschung  ; 336)
SP  - 19
PB  - Zentralinst. fuer Kernforschung
CY  - Rossendorf
ER  - 
TY  - JOUR
A1  - Müller-Veggian, Mattea
A1  - Beuscher, H.
A1  - Gono, Y.
T1  - Systematics of 10⁺ isomers in the N=78 nuclei
JF  - Annual report 1977 / Institut für Kernphysik Kernforschungsanlage Jülich
Y1  - 1978
N1  - Spezielle Berichte der Kernforschungsanlage Jülich ; 15
SP  - 33
EP  - 34
PB  - Verlag des Forschungszentrums Jülich
CY  - Jülich
ER  - 
TY  - JOUR
A1  - Müller-Veggian, Mattea
A1  - Beuscher, H.
A1  - Gono, Y.
T1  - High spin states and isomers in nuclei with neutron number N=80
JF  - Frühjahrstagung ... des Fachausschusses Kernphysik und Hochenergiephysik der DPG (Sektion A: Kernphysik) / Deutsche Physikalische Gesellschaft (1978)
Y1  - 1978
SP  - 841
EP  - 842
PB  - Physik-Verlag
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Müller-Veggian, Mattea
A1  - Beuscher, H.
A1  - Gono, Y.
T1  - Isomeric 10⁺ states in nuclei with N=78
JF  - Proceedings of the International Conference on Nuclear Structure : Tokyo, Sept. 5 - 10, 1977 / ed. by T. Marumori. - Journal of the Physical Society of Japan ; Vol. 44, 1978 : Suppl.
Y1  - 1978
N1  - International Conference on Nuclear Structure <1977, Tokyo>
SP  - 861
PB  - Physical Soc. of Japan
CY  - Tokyo
ER  - 
TY  - JOUR
A1  - Müller-Veggian, Mattea
A1  - Beuscher, H.
A1  - Gono, Y.
A1  - Lieder, R. M.
T1  - Side bands in ¹⁷² Hf
JF  - Frühjahrstagung ... des Fachausschusses Kernphysik und Hochenergiephysik der DPG (Sektion A: Kernphysik) / Deutsche Physikalische Gesellschaft (1977)
Y1  - 1977
SP  - 940
ER  - 
TY  - JOUR
A1  - Müller-Veggian, Mattea
A1  - Beuscher, H.
A1  - Gono, Y.
A1  - Lieder, R. M.
T1  - Systematic features of isomeric states in Ce, Sm, Nd nuclei
JF  - Frühjahrstagung ... des Fachausschusses Kernphysik und Hochenergiephysik der DPG (Sektion A: Kernphysik) / Deutsche Physikalische Gesellschaft (1977)
Y1  - 1977
SP  - 892
ER  -