MIA computer simulation test results report

Results of the first noise susceptibility computer simulation tests of the complete MIA receiver analytical model are presented. Computer simulation tests were conducted with both Gaussian and pulse noise inputs. The results of the Gaussian noise tests were compared to results predicted previously and were found to be in substantial agreement. The results of the pulse noise tests will be compared to the results of planned analogous tests in the Data Bus Evaluation Laboratory at a later time. The MIA computer model is considered to be fully operational at this time

Duralumin

The use of duralumin in the construction of aircraft makes an account of the properties of this material desirable especially with reference to its working qualities as developed by experience

Continuous Time Monte Carlo for Lattice QCD in the Strong Coupling Limit

We present results for lattice QCD in the limit of infinite gauge coupling, obtained from a worm-type Monte Carlo algorithm on a discrete spatial lattice but with continuous Euclidean time. This is obtained by sending both the anisotropy parameter gamma^2 \sim a/a_t and the number of time-slices N_\tau to infinity, keeping the ratio \gamma^2/N_\tau \sim aT fixed. The obvious gain is that no continuum extrapolation N_\tau -> \infty has to be carried out. Moreover, the algorithm is faster and the sign problem disappears. We compare our computations with those on discrete lattices. We determine the phase diagram as a function of temperature and baryon chemical potential.Comment: 4 pages, Proceedings for Quark Matter 2011 Conference, May 23-28, 2011, Annecy, Franc

Force indeterminacy in the jammed state of hard disks

Granular packings of hard discs are investigated by means of contact dynamics which is an appropriate technique to explore the allowed force-realizations in the space of contact forces. Configurations are generated for given values of the friction coefficient, and then an ensemble of equilibrium forces is found for fixed contacts. We study the force fluctuations within this ensemble. In the limit of zero friction the fluctuations vanish in accordance with the isostaticity of the packing. The magnitude of the fluctuations has a non-monotonous friction dependence. The increase for small friction can be attributed to the opening of the angle of the Coulomb cone, while the decrease as friction increases is due to the reduction of connectivity of the contact-network, leading to local, independent clusters of indeterminacy. We discuss the relevance of indeterminacy to packings of deformable particles and to the mechanical response properties.Comment: 4 pages, 3 figures. Minor changes, journal reference adde

Shear band formation in granular media as a variational problem

Strain in sheared dense granular material is often localized in a narrow region called shear band. Recent experiments in a modified Couette cell provided localized shear flow in the bulk away from the confining walls. The non-trivial shape of the shear band was measured as the function of the cell geometry. First we present a geometric argument for narrow shear bands which connects the function of their surface position with the shape in the bulk. Assuming a simple dissipation mechanism we show that the principle of minimum dissipation of energy provides a good description of the shape function. Furthermore, we discuss the possibility and behavior of shear bands which are detached from the free surface and are entirely covered in the bulk.Comment: 4 pages, 5 figures; minor changes, typos and journal-ref adde

The effect of contact torques on porosity of cohesive powders

The porosity of uniaxially compacted cohesive powders depends on the applied stress (including gravity). The case, where these stresses are weak, is considered. The compaction results in a porosity which is a function of sliding, rolling and torsion friction. By contact dynamics simulations it is shown that the influences of contact torques (static rolling and torsion friction) on the porosity are significant and approximately additive. The relevance for nano-powder pressure sintering is discussed.Comment: 5 pages, 5 figure

Unjamming of Granular Packings due to Local Perturbations: Stability and Decay of Displacements

We study the mechanical response generated by local deformations in jammed packings of rigid disks. Based on discrete element simulations we determine the critical force of the local perturbation that is needed to break the mechanical equilibrium and examine the generated displacement field. Displacements decay as a power law of the distance from the perturbation point. The decay exponent and the critical force exhibit nontrivial dependence on the friction: Both quantities are nonmonotonic and have a sharp maximum at the friction coefficient 0.1. We find that the mechanical response properties are closely related to the problem of force-indeterminacy where similar nonmonotonic behavior was observed previously. We establish direct connection between the critical force and the ensemble of static force networks.Comment: 4 pages, 4 figure

Treating Depression Mindfully in a Day Hospital:a Randomised Controlled Pilot Study

Objectives: Recent preliminary evidence suggests that mindfulness-based programmes may be beneficial in the treatment of patients suffering from current depression. Due to the heterogeneity of patients with this diagnosis, a specialisation in treatment concepts for subgroups of patients may be beneficial. Methods: This randomised controlled pilot study investigated the effectiveness of an eight-week mindfulness-based day hospital treatment for patients with current depression and work-related conflicts (MDT-DH) under naturalistic conditions. Eighty-one currently depressed patients with work-related conflicts were randomly assigned to either MDT-DH (including personalised psychopharmacological treatment if necessary) or a waitlist condition including a psychopharmacological consultation (PCC). Outcomes were assessed at post-treatment and at 8-month follow-up. The primary outcome was depression severity (Beck Depression Inventory) at post-treatment. Secondary outcomes were work ability (Work Ability Index) and mindfulness (Kentucky Inventory of Mindfulness Skills). Results: A multilevel analysis revealed that compared with patients in PCC, patients in the MDT-DH group showed a greater reduction in depression severity, higher work ability and heightened levels of mindfulness after 8 weeks than patients in the PCC group. These improvements were stable during the 8-month follow-up period. Conclusions: Findings of the present pilot study suggest that a treatment concept involving intensive training in mindfulness can be successfully established in a day hospital and leads to clinically meaningful reductions in depression severity and increases in work ability in patients suffering from current depression. The generalisability of the findings may be limited due to small sample size, selective patient group and study design