Muscle Fatigue in Musculoskeletal Numerical Models

The investigation of the musculoskeletal system is a challenging task, since comprehensive knowledge of muscle and joint forces within the human body is required. Therefore, in recent years numerical models have been developed for a better understanding of the musculoskeletal system. Especially for the investigation of long-term effects, the issue of muscle fatigue needs to be taken into consideration in these models. The objectives of this thesis was to develop a novel EMG based muscle fatigue algorithm and the implementation into a state-of-the-art musculoskeletal modelling system. This included the investigation of the progress of muscle fatigue of single muscles, as well as the behaviour of muscle recruitment pattern when experiencing fatigue. Therefore, two experimental studies were conducted in the course of this thesis, in order to analyse the progress of muscle fatigue of single muscles in correlation with relative muscle loadings and to study the behaviour of muscle recruitment pattern of thorax muscles when experiencing fatigue. Based on the results of the first study a fatigue algorithm was developed and implemented to the AnyBody Modeling SystemTM (AMS). Both experimental studies were simulated in the altered AMS to validate the fatigue algorithm and to analyse the behaviour of the muscle recruitment solver of the modified system. The results show a good correlation between the simulated muscle fatigue and the experimental data. Furthermore, it revealed a reduction of maximum force capacity of the muscles of about 10-15% compared to the non-fatigued condition. The analysis of the muscle recruitment pattern indicated an additional activation of muscles in the upper back as well as the abdomen. The numerical simulation of these exercises in the AMS revealed a shift of muscle activity to the upper back

EmoCyclingConcept – Smart and safe mobility – Workshop

Safety is one of the most important goods we have these days. When it comes to traffic in our cities and the interactions between the different traffic participants it is especially the everyday cyclist whose need for safety is crucial. How can you measure a good feeling or perceived safety? One possibility is to do a survey for some specific routes through the cities. To get more detailed results you invert the idea of safety. You measure unsafety by collecting negative emotional experiences while cycling. But how is this done? The Department of Computer Aided Design in Urban Planning and Architecture (CPE) from the University of Kaiserslautern has dealt with this method for more than 5 years. Meanwhile we collected data in the context of accessibility of pedestrians (Bergner, et al. 2011) as well as cyclists (Buschlinger, et al. 2013) in different countries and with a variety of cooperations. Within the latest DFG-project “Urban Emotions”, over 75 cyclists have been measured. For this method, three different instruments are used: The main instrument is the “Smartband” (www.bodymonitor.de). It measures the galvanic skin response as well as the skin temperature to analyse the body signals. There is a special relation between psychological arousal and physiological reactions like the skin conductance and the temperature (Kreibig 2010). If you recognize this unique pattern, in which the level of skin conductance rises and the skin temperature decreases 3 seconds later, it can be interpreted as a “negative arousal” (Bergner et al. 2011). The body data is located with a GPS-tracker. For further analysis a GoPro records the trip. With the help of this setup, it is possible to identify severe problems (Rittel 1973), on which urban planners should react by trying to eliminate them. The project should be understood as a work for progressing research, dealing with the optimization of the method by testing in use cases

Time-resolved observation of spin-charge deconfinement in fermionic Hubbard chains

Elementary particles such as the electron carry several quantum numbers, for example, charge and spin. However, in an ensemble of strongly interacting particles, the emerging degrees of freedom can fundamentally differ from those of the individual constituents. Paradigmatic examples of this phenomenon are one-dimensional systems described by independent quasiparticles carrying either spin (spinon) or charge (holon). Here we report on the dynamical deconfinement of spin and charge excitations in real space following the removal of a particle in Fermi-Hubbard chains of ultracold atoms. Using space- and time-resolved quantum gas microscopy, we track the evolution of the excitations through their signatures in spin and charge correlations. By evaluating multi-point correlators, we quantify the spatial separation of the excitations in the context of fractionalization into single spinons and holons at finite temperatures

A subradiant optical mirror formed by a single structured atomic layer

Efficient and versatile interfaces for the interaction of light with matter are an essential cornerstone for quantum science. A fundamentally new avenue of controlling light-matter interactions has been recently proposed based on the rich interplay of photon-mediated dipole-dipole interactions in structured subwavelength arrays of quantum emitters. Here we report on the direct observation of the cooperative subradiant response of a two-dimensional (2d) square array of atoms in an optical lattice. We observe a spectral narrowing of the collective atomic response well below the quantum-limited decay of individual atoms into free space. Through spatially resolved spectroscopic measurements, we show that the array acts as an efficient mirror formed by only a single monolayer of a few hundred atoms. By tuning the atom density in the array and by changing the ordering of the particles, we are able to control the cooperative response of the array and elucidate the interplay of spatial order and dipolar interactions for the collective properties of the ensemble. Bloch oscillations of the atoms out of the array enable us to dynamically control the reflectivity of the atomic mirror. Our work demonstrates efficient optical metamaterial engineering based on structured ensembles of atoms and paves the way towards the controlled many-body physics with light and novel light-matter interfaces at the single quantum level.Comment: 8 pages, 5 figures + 12 pages Supplementary Infomatio

Das Beweismaß der "überwiegenden Wahrscheinlichkeit" im Rahmen der Glaubhaftmachung einer Fortbestehensprognose - zugleich Replik auf die Entgegnung von Drukarczyk/Schüler, WPg 2003, S. 56 bis 67

going concern assumption, insolvency, probability

The competitive strength of European, Japanese and US suppliers on ASEAN markets.

Internationaler Wettbewerb; Multinationales Unternehmen; Direktinvestition; Internationales Marketing; Firmeninterner Handel; Industriegüteraußenhandel; EU-Staaten; Japan; USA;

Thermo-mechanical coupling in fiber-reinforced continua: mixed finite element formulations and energy-momentum time integration

Our research activity is motivated by accurate dynamic simulations of fiber- reinforced materials in light-weight structures. In order to accomplish this, we have to take various steps. The material behavior is formulated with an anisotropic, polyconvex strain energy function. We combine different mixed element formulations (e.g. see Ref- erence [2] or [3]) with a Galerkin time integrator as shown in Reference [5]. This reduces the volumetric locking effect of an incompressible matrix material as well as the locking effect due to stiff fibers. In addition, we increase the accuracy by using Galerkin-based higher-order time integrators. Since in long-term simulations a hugh energy error is a strong problem, we apply the mixed finite element formulations to an energy-momentum time integration scheme (see Reference [6]). In the next step, we extend the material formulation by adding a thermo-mechanical coupling as shown in Reference [7]. Here we also describe the directional heat conduction of the fiber. As numerical examples with multiple material domains and families of fibers serve cooks cantilever beam as in Ref- erence [5]. The Dirichlet boundary conditions are modelled by the Lagrange-multiplier method (see Reference [7]) and as Neumann boundary condition a pressure distribution is used