@inproceedings{TakenagaWernerSawadaetal.2012, author = {Takenaga, Shoko and Werner, Frederik and Sawada, Kazuaki and Sch{\"o}ning, Michael Josef}, title = {Comparison of label-free ACh image sensors based on CCD and LAPS}, isbn = {978-3-9813484-2-2}, doi = {10.5162/IMCS2012/4.2.6}, pages = {356 -- 359}, year = {2012}, language = {en} } @inproceedings{SuryoputriGhaderiLinderetal.2017, author = {Suryoputri, Nathania and Ghaderi, Aydin and Linder, Peter and Kotliar, Konstantin and G{\"o}ttler, Jens and Sorg, Christian and Grimmer, Timo}, title = {Does hemodynamic response function change in Alzheimer disease?}, series = {2nd YRA MedTech Symposium 2017 : June 8th - 9th / 2017 / Hochschule Ruhr-West}, booktitle = {2nd YRA MedTech Symposium 2017 : June 8th - 9th / 2017 / Hochschule Ruhr-West}, editor = {Erni, Daniel and Fischerauer, Alice and Himmel, J{\"o}rg and Seeger, Thomas and Thelen, Klaus}, publisher = {Universit{\"a}t Duisburg-Essen}, address = {Duisburg}, organization = {MedTech Symposium}, isbn = {978-3-9814801-9-1}, doi = {10.17185/duepublico/43984}, pages = {92}, year = {2017}, language = {en} } @inproceedings{StreunAlKaddoumParletal.2012, author = {Streun, M. and Al-Kaddoum, R. and Parl, C. and Pietrzyk, U. and Ziemons, Karl and Waasen, S. van}, title = {Simulation studies of optical photons in monolithic block scintillators}, series = {2011 IEEE Nuclear Science Symposium Conference Record (NSS/MIC)}, booktitle = {2011 IEEE Nuclear Science Symposium Conference Record (NSS/MIC)}, publisher = {IEEE}, address = {New York}, isbn = {978-1-4673-0120-6 (electronic ISBN)}, doi = {10.1109/NSSMIC.2011.6154621}, pages = {1380 -- 1382}, year = {2012}, abstract = {The interest in PET detectors with monolithic block scintillators is growing. In order to obtain high spatial resolutions dedicated positioning algorithms are required. But even an ideal algorithm can only deliver information which is provided by the detector. In this simulation study we investigated the light distribution on one surface of cuboid LSO scintillators of different size. Scintillators with a large aspect ratio (small footprint and large height) showed significant position information only for a minimum interaction depth of the gamma particle. The results allow a quantitative estimate for a useful aspect ratio.}, language = {en} } @inproceedings{StadlerEmbsZerlinetal.2007, author = {Stadler, Andreas M. and Embs, Jan P. and Zerlin, Kay and Digel, Ilya and Artmann, Gerhard and Zaccai, Joe and B{\"u}ldt, Georg}, title = {Temperature transitions of hemoglobin and cytosolic water diffusion in human red blood cells : [poster]}, year = {2007}, abstract = {Background Hemoglobin interactions in red blood cells Hemoglobin dynamics in human red blood cells Diffusion of H2O in red blood cells}, subject = {Erythrozyt}, language = {en} } @inproceedings{StaatTranPham2008, author = {Staat, Manfred and Tran, Thanh Ngoc and Pham, Phu Tinh}, title = {Limit and shakedown reliability analysis by nonlinear programming}, year = {2008}, abstract = {7th International Conference on Reliability of Materials and Structures (RELMAS 2008). June 17 - 20, 2008 ; Saint Petersburg, Russia. pp 354-358. Reprint with corrections in red Introduction Analysis of advanced structures working under extreme heavy loading such as nuclear power plants and piping system should take into account the randomness of loading, geometrical and material parameters. The existing reliability are restricted mostly to the elastic working regime, e.g. allowable local stresses. Development of the limit and shakedown reliability-based analysis and design methods, exploiting potential of the shakedown working regime, is highly needed. In this paper the application of a new algorithm of probabilistic limit and shakedown analysis for shell structures is presented, in which the loading and strength of the material as well as the thickness of the shell are considered as random variables. The reliability analysis problems may be efficiently solved by using a system combining the available FE codes, a deterministic limit and shakedown analysis, and the First and Second Order Reliability Methods (FORM/SORM). Non-linear sensitivity analyses are obtained directly from the solution of the deterministic problem without extra computational costs.}, subject = {Finite-Elemente-Methode}, language = {en} } @inproceedings{StaatTran2022, author = {Staat, Manfred and Tran, Ngoc Trinh}, title = {Strain based brittle failure criteria for rocks}, series = {Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training, Hanoi, December 2-3, 2022}, booktitle = {Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training, Hanoi, December 2-3, 2022}, publisher = {Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik)}, address = {Hanoi}, isbn = {978-604-357-084-7}, pages = {500 -- 509}, year = {2022}, abstract = {When confining pressure is low or absent, extensional fractures are typical, with fractures occurring on unloaded planes in rock. These "paradox" fractures can be explained by a phenomenological extension strain failure criterion. In the past, a simple empirical criterion for fracture initiation in brittle rock has been developed. But this criterion makes unrealistic strength predictions in biaxial compression and tension. A new extension strain criterion overcomes this limitation by adding a weighted principal shear component. The weight is chosen, such that the enriched extension strain criterion represents the same failure surface as the Mohr-Coulomb (MC) criterion. Thus, the MC criterion has been derived as an extension strain criterion predicting failure modes, which are unexpected in the understanding of the failure of cohesive-frictional materials. In progressive damage of rock, the most likely fracture direction is orthogonal to the maximum extension strain. The enriched extension strain criterion is proposed as a threshold surface for crack initiation CI and crack damage CD and as a failure surface at peak P. Examples show that the enriched extension strain criterion predicts much lower volumes of damaged rock mass compared to the simple extension strain criterion.}, language = {en} } @inproceedings{StaatHeitzer1997, author = {Staat, Manfred and Heitzer, Michael}, title = {Limit and shakedown analysis for plastic design}, year = {1997}, abstract = {Limit and shakedown theorems are exact theories of classical plasticity for the direct computation of safety factors or of the load carrying capacity under constant and varying loads. Simple versions of limit and shakedown analysis are the basis of all design codes for pressure vessels and pipings. Using Finite Element Methods more realistic modeling can be used for a more rational design. The methods can be extended to yield optimum plastic design. In this paper we present a first implementation in FE of limit and shakedown analyses for perfectly plastic material. Limit and shakedown analyses are done of a pipe-junction and a interaction diagram is calculated. The results are in good correspondence with the analytic solution we give in the appendix.}, subject = {Einspielen }, language = {en} } @inproceedings{StaatHeitzer2002, author = {Staat, Manfred and Heitzer, Michael}, title = {The restricted influence of kinematic hardening on shakedown loads}, year = {2002}, abstract = {Structural design analyses are conducted with the aim of verifying the exclusion of ratcheting. To this end it is important to make a clear distinction between the shakedown range and the ratcheting range. In cyclic plasticity more sophisticated hardening models have been suggested in order to model the strain evolution observed in ratcheting experiments. The hardening models used in shakedown analysis are comparatively simple. It is shown that shakedown analysis can make quite stable predictions of admissible load ranges despite the simplicity of the underlying hardening models. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis. Both give identical or similar shakedown ranges. Structural shakedown analyses show that the loading may have a more pronounced effect than the hardening model.}, subject = {Biomedizinische Technik}, language = {en} } @inproceedings{StaatHeitzer2000, author = {Staat, Manfred and Heitzer, Michael}, title = {Direct static FEM approach to limit and shakedown analysis}, year = {2000}, abstract = {Safety and reliability of structures may be assessed indirectly by stress distributions. Limit and shakedown theorems are simplified but exact methods of plasticity that provide safety factors directly in the loading space. These theorems may be used for a direct definition of the limit state function for failure by plastic collapse or by inadaptation. In a FEM formulation the limit state function is obtained from a nonlinear optimization problem. This direct approach reduces considerably the necessary knowledge of uncertain technological input data, the computing time, and the numerical error. Moreover, the direct way leads to highly effective and precise reliability analyses. The theorems are implemented into a general purpose FEM program in a way capable of large-scale analysis.}, subject = {Einspielen }, language = {en} } @inproceedings{StaatDuong2016, author = {Staat, Manfred and Duong, Minh Tuan}, title = {Smoothed Finite Element Methods for Nonlinear Solid Mechanics Problems: 2D and 3D Case Studies}, series = {Proceedings of the National Science and Technology Conference on Mechanical - Transportation Engineering (NSCMET 2016), 13th October 2016, Hanoi, Vietnam, Vol.2}, booktitle = {Proceedings of the National Science and Technology Conference on Mechanical - Transportation Engineering (NSCMET 2016), 13th October 2016, Hanoi, Vietnam, Vol.2}, pages = {440 -- 445}, year = {2016}, abstract = {The Smoothed Finite Element Method (SFEM) is presented as an edge-based and a facebased techniques for 2D and 3D boundary value problems, respectively. SFEMs avoid shortcomings of the standard Finite Element Method (FEM) with lower order elements such as overly stiff behavior, poor stress solution, and locking effects. Based on the idea of averaging spatially the standard strain field of the FEM over so-called smoothing domains SFEM calculates the stiffness matrix for the same number of degrees of freedom (DOFs) as those of the FEM. However, the SFEMs significantly improve accuracy and convergence even for distorted meshes and/or nearly incompressible materials. Numerical results of the SFEMs for a cardiac tissue membrane (thin plate inflation) and an artery (tension of 3D tube) show clearly their advantageous properties in improving accuracy particularly for the distorted meshes and avoiding shear locking effects.}, language = {en} }