Dependence of dielectric constant and loss tangent on electric field in antiferroelectric squaric acid crystal

The double-time thermal Green function method with the symmetric and antisymmetric decoupling scheme and modified pseudospin model proposed by Li and Qin for squaric acid have been used in present study to discuss the effect of electric field on some dielectric properties. Expressions for shift, width, soft mode frequency, dielectric constant, loss and transition temperature have been evaluated. By fitting model values of physical quantities in the theoretical expressions thermal dependence of antiferroelectric mode frequency, dielectric constant and loss have been calculated in presence of electric field in the vicinity of transition temperature. Theoretical results are similar to other antiferroelectric crystals

A Case Study on Improving Accessibility of Healthcare Care Facility in Low-resource Settings

Accessibility in a hospital is challenging for people in low-income countries due to a lack of accessible mediums to communicate wayfinding, accessibility, and healthcare information. This results in delays and stress but can also result in sub-optimal treatment or sometimes a complete lack of treatment for the visitors. Sensible physical and digital interventions can greatly ease the experience of visitors and reduce the work-related stress of healthcare providers. We present a case study on wayfinding and service design for a mega ophthalmic care facility that has a daily footfall of 2500 patients. From our mixed-methods study we identified: (i) there are very few accessible mediums available to communicate wayfinding, accessibility, and healthcare information; (ii) there is a lack of inclusively designed interventions to accommodate the diversity of visitors; (iii) spatial ambiguity and situational impairment due to crowd density exasperate the situation and (iv) there exist missing as well as misleading information. We developed a spectrum of solutions on the environmental and digital infrastructures available within this context to deliver wayfinding and procedural information. We completed a progressive intervention across digital and physical mediums over a duration of 18 months. This has shown the impact of each medium on visitors' experience. We found the choice of interface to access information depends on the ease of access, and ease of access depends on visitors' abilities. Therefore, both the environment and digital mediums are found to be useful for visitors. Based on these empirical findings, we draw recommendations for an inclusive service design that incorporates using elements of the environment, human and digital infrastructure to support a more positive healthcare visitors experience

Analysis of cybersecurity threats in Industry 4.0: the case of intrusion detection

Nowadays, industrial control systems are experiencing a new revolution with the interconnection of the operational equipment with the Internet, and the introduction of cutting-edge technologies such as Cloud Computing or Big data within the organization. These and other technologies are paving the way to the Industry 4.0. However, the advent of these technologies, and the innovative services that are enabled by them, will also bring novel threats whose impact needs to be understood. As a result, this paper provides an analysis of the evolution of these cyber-security issues and the requirements that must be satis ed by intrusion detection defense mechanisms in this context.Springer ; Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Theoretical investigation of structural phase transition and microwave dielectric properties in triglycine sulphate (TGS) crystal

208-212By using the extended two sublattice pseudospin coupled mode (PLCM) model by summing third-order and fourth-order anharmonic interactions as well as extra spin lattice interactions, direct spin-spin interaction and electric field terms is considered for triglycine sulphate crystal (TGS) crystal. With the help of double-time thermal dependent Green’s function method and Dyson’s equation, expressions for soft mode frequency dielectric constant and loss tangent for triglycine sulphate crystal. By fitting the model values in the theoretical expressions, thermal variations of soft mode frequency, dielectric constant and loss tangent are calculated and compare well with the experimental data of Bye et al

Exoplanet properties from Lick, Keck and AAT

Doppler-shift measurements with a remarkable precision of Δλ/λ=3×10-9, corresponding to velocities of 1 m s-1, have been made repeatedly of 2500 stars located within 300 light years. The observed gravitational perturbations of the stars have revealed 250 orbiting planets, with 27 that cross in front of the host star, blocking a fraction of the starlight to allow measurement of the planet's mass, radius and density. Two new discoveries are the first good analog of Jupiter (HD 154345b) and the first system of five planets (55 Cancri). The predominantly eccentric orbits of exoplanets probably result from planet planet gravitational interactions or angular momentum exchange by mean-motion resonances. The planet mass distribution ranges from ~15 MJUP to as low as ~5 MEarth and rises toward lower masses as dN/dM~M-1.1. The distribution with orbital distance, a, rises (in logarithmic intervals) as dN/d log a~a+0.4. Extrapolation and integration suggests that 19% of all Sun-like stars harbor a gas-giant planet within 20 AU, but there remains considerable incompleteness for large orbits. Beyond 20 AU, the occurrence of gas-giant planets may be less than a few per cent as protoplanetary disk material there has lower densities and is vulnerable to destruction. Jupiter-mass planets occur more commonly around more massive stars than low mass stars. The transit of the Neptune-mass planet, Gliese 436b, yields a density of 1.55 g cm-3 suggesting that its interior has an iron silicate core surrounded by an envelope of water ice and an outer H He shell. Planets with masses as low as five Earth-masses may be commonly composed of iron nickel, rock and water along with significant amounts of H and He, making the term 'super-Earth' misleading. The transiting planet HD147506b has high orbital eccentricity but no significant orbital inclination to the line of sight, presenting a puzzle about its history. Its orbit together with the mean motion resonances of 4 of the 22 multi-planet systems provides further evidence for the role of planet planet interactions in shaping planetary architectures

Spin accumulation induced resistance in mesoscopic ferromagnet/ superconductor junctions

We present a description of spin-polarized transport in mesoscopic ferromagnet-superconductor (F/S) systems, where the transport is diffusive, and the interfaces are transparent. It is shown that the spin reversal associated with Andreev reflection generates an excess spin density close to the F/S interface, which leads to a spin contact resistance. Expressions for the contact resistance are given for two terminal and four terminal geometries. In the latter the sign depends on the relative magnetization of the ferromagnetic electrodes.Comment: RevTeX 10 pages, 4 figures, submitted to Phys.Rev. Let