The Temperature Dependant Efficiency of Photovoltaic Modules - a Long Term Evaluation of Experimental Measurements

Non

Seesaw and noncommutative geometry

The 1-loop corrections to the seesaw mechanism in the noncommutative standard model are computed. Other consequences of the Lorentzian signature in the inner space are summarised.Comment: Dedicated to Alain Connes on the occasion of his 60th birthda

Performance of different constitutive soil models: from element tests to the simulation of vibratory pile driving tests

The present study deals with the investigation of the applicability (by means of parameter calibration), robustness and prediction quality of advanced constitutive soil models for the numerical investigation of complex geotechnical problems. The range of available constitutive soil models extends from simple linear to time-dependent and hydromechanically coupled nonlinear modelling approaches. It is the user's task to select a constitutive model suitable for the problem at hand. This requires in-depth knowledge of the soil behaviour as well as the strengths and weaknesses of the available constitutive models, most of which have only been validated using element test simulations. The procedure from parameter calibration using laboratory tests under well-defined boundary conditions (element tests) to the simulation of boundary value problems is complex in many respects and is often not followed with advanced constitutive models due to the large number of parameters required and the necessary laboratory tests. In this paper, the prediction quality of three models, namely Hypoplasticity with Intergranular Strain, Sanisand and Hypoplasticity with Intergranular Strain Anisotropy is inspected. The investigation is carried out based on back-calculations of laboratory tests and a well-documented model test to evaluate their suitability in representing complex soil mechanical aspects, such as the material behaviour under cyclic loading, particularly pore pressure accumulation. The parameter calibration is performed both "manually" as well as with a specially developed automatic calibration software. Subsequently, model tests of vibratory pile driving in water-saturated sand are simulated using the previously calibrated parameters

Persistent and polarised global actin flow is essential for directionality during cell migration

Cell migration is hypothesized to involve a cycle of behaviours beginning with leading edge extension. However, recent evidence suggests that the leading edge may be dispensable for migration, raising the question of what actually controls cell directionality. Here, we exploit the embryonic migration of Drosophila macrophages to bridge the different temporal scales of the behaviours controlling motility. This approach reveals that edge fluctuations during random motility are not persistent and are weakly correlated with motion. In contrast, flow of the actin network behind the leading edge is highly persistent. Quantification of actin flow structure during migration reveals a stable organization and asymmetry in the cell-wide flowfield that strongly correlates with cell directionality. This organization is regulated by a gradient of actin network compression and destruction, which is controlled by myosin contraction and cofilin-mediated disassembly. It is this stable actin-flow polarity, which integrates rapid fluctuations of the leading edge, that controls inherent cellular persistence

Experimental behaviour of composite girders with steel undulating web and thinâ€walled shear connectors Hilti Stripcon

Two tests of realâ€size composite steel and concrete girders are described. The girders had spans 7,5 m, thinâ€walled undulating webs (WT girders) and concrete deck 120/1500 mm concreted into profile steel sheeting TR 60/235/0,75. Thinâ€walled shear connectors Hilti Stripcon were used and fastened via powder actuated fasteners. Setup of the tests, relevant instrumentation and measuring procedure are presented. The girder tests supplemented large series of push tests of connectors Stripcon performed at CTU in Prague. One of the composite girders was designed with fullâ€shear connection while the second one with extremely low partial shear connection (44 %). Simple preliminary linear calculations proved that experimental strength capacities of the girders are in good agreement with the calculated values, however, the deflection are due to flexibility of the connectors higher. Buckling shear capacity of the undulating webs in both tests was higher than shear at collapse of the girders. Another test dealing with interaction of web buckling in shear and Stripcon shear connection is under progress. Comparison of theoretical and experimental results is performed and recommendations for practical design are presented. First Published Online: 14 Oct 201