Reflection and Refraction of Quasi-P Wave Due to a Sandwich Isotropic Layer Between Two Monoclinic Half-Spaces

The reflection and refraction of quasi-P(qP) wave below a transition isotropic layer sandwiched between two monoclinic media have studied. Due to incident of qP-wave at the interface of monoclinic lower half space and isotropic transition layer of thickness H, it will give rise to reflected qP, qSV, qSH-wave in the lower monoclinic half space and reflected P-wave and SV-wave at the isotropic transition layer of thickness H. As there is mother interface between transition layer and monoclinic upper-half space extended up to infinity, these two refracted P and SV-wave will incident at the interface with angle and 64 respectively. These two waves will produce reflected P and SV-wave in the transition layer and refracted qP, qSV and qSH-wave in the upper half-space of monoclinic medium in both the cases. This problem has been solved to obtain the reflection and refraction coefficients for all the waves generated using boundary conditions and the balance in energy flux normal to the boundary. Absolute numerical values of all the reflection and refraction coefficients have been obtained for a particular set up of material constants for isotropic and monoclinic media for different values of thickness of transition layer

Is toxicity a curse or blessing, or both?—Searching answer from a disease-induced consumer-resource system

Chemical toxins exposed in environments and disease outbreaks are global threats to ecosystems in the present era of the anthropocene. Toxin favors disease progression trivially. However, it is still unclear whether the toxin impacts disease elimination too. Toxin also has a significant role in amplifying the risk of disease-induced consumer extinction. Identification of the extinction vortex and its associated precursors are the two most important pillars for understanding the effect of the toxin on the sustainability of ecosystems. On the other hand, the contribution of toxin as a potential agent for stabilizing a disease-induced consumer-resource system is still unclear. Although disease stabilizes the system in absence of toxicity. In order to address this, we consider a mathematical model of disease transmission in the consumer population where both ecological and epidemiological traits are affected by environmental toxins. The proposed model integrates two compartments (susceptible and infected) for consumers and the resource, where the toxin is incorporated in the form of species body burdens. Apart from the formal stability analysis, we extensively use codim-1 and codim-2 bifurcation through MATCONT software for understanding the different dynamical regimes of disease progression and elimination. These derived regimes will be helpful to raise the alarm and take intervention policies

Effect of Trace Addition on the Microstructural Degradation of Cu-Zn-AI Shape Memory Alloy

The effect of trace addition of Zr, Ti and misch metal (MM) on the grain growth kinetics of Cu Zn Al shape memory alloy with reference to pinning caused by the precipitates at /ow temperature ageing and solute drag mechanisms. It been demonstrated that solute drag mechanism favoured nucleation of variants and grain refinement

Magnetoelastic plane waves in rotating media in thermoelasticity of type II (G-N model)

A study is made of the propagation of time-harmonic plane waves in an infinite, conducting, thermoelastic solid permeated by a uniform primary external magnetic field when the entire medium is rotating with a uniform angular velocity. The thermoelasticity theory of type II (G-N model) (1993) is used to study the propagation of waves. A more general dispersion equation is derived to determine the effects of rotation, thermal parameters, characteristic of the medium, and the external magnetic field. If the primary magnetic field has a transverse component, it is observed that the longitudinal and transverse motions are linked together. For low frequency (χ≪1, χ being the ratio of the wave frequency to some standard frequency ω∗), the rotation and the thermal field have no effect on the phase velocity to the first order of χ and then this corresponds to only one slow wave influenced by the electromagnetic field only. But to the second order of χ, the phase velocity, attenuation coefficient, and the specific energy loss are affected by rotation and depend on the thermal parameters cT, cT being the nondimensional thermal wave speed of G-N theory, and the thermoelastic coupling εT, the electromagnetic parameters εH, and the transverse magnetic field RH. Also for large frequency, rotation and thermal field have no effect on the phase velocity, which is independent of primary magnetic field to the first order of (1/χ) (χ≫1), and the specific energy loss is a constant, independent of any field parameter. However, to the second order of (1/χ), rotation does exert influence on both the phase velocity and the attenuation factor, and the specific energy loss is affected by rotation and depends on the thermal parameters cT and εT, electromagnetic parameter εH, and the transverse magnetic field RH, whereas the specific energy loss is independent of any field parameters to the first order of (1/χ)

Non-equilibrium VLS-grown stable ST12-Ge thin film on Si substrate: A study on strain-induced band-engineering

The current work describes a novel method of growing thin films of stable crystalline ST12-Ge, a high pressure polymorph of Ge, on Si substrate by a non-equilibrium VLS-technique. The study explores the scheme of band engineering of ST12-Ge by inducing process-stress into it as a function of the growth temperature and film thickness. In the present work, ST12-Ge films are grown at 180 C - 250 C to obtain thicknesses of ~4.5-7.5 nm, which possess extremely good thermal stability up to a temperature of ~350 C. Micro-Raman study shows the stress induced in such ST12-Ge films to be compressive in nature and vary in the range of ~0.5-7.5 GPa. The measured direct band gap is observed to vary within 0.688 eV to 0.711 eV for such stresses, and four indirect band gaps are obtained to be 0.583 eV, 0.614-0.628 eV, 0.622-0.63 eV and 0.623-0.632 eV, accordingly. The corresponding band structures for unstrained and strained ST12-Ge are calculated by performing DFT simulation, which shows that a compressive stress transforms the fundamental band gap at M-G valley from indirect to direct one. Henceforth, the possible route of strain induced band engineering in ST12-Ge is explored by analyzing all the transitions in strained and unstrained band structures along with substantiation of the experimental results and theoretical calculations. The investigation shows that unstrained ST12-Ge is a natural n-type semiconductor which transforms into p-type upon incorporation of a compressive stress of ~5 GPa, with the in-plane electron effective mass components at M-G band edge to be ~0.09 me. Therefore, such band engineered ST12-Ge exhibits superior mobility along with its thermal stability and compatibility with Si, which can have potential applications to develop high-speed MOS devices for advanced CMOS technology

Measurement of electrical properties of electrode materials for the bakelite Resistive Plate Chambers

Single gap (gas gap 2 mm) bakelite Resistive Plate Chamber (RPC) modules of various sizes from 10 cm \times 10 cm to 1 m \times 1 m have been fabricated, characterized and optimized for efficiency and time resolution. Thin layers of different grades of silicone compound are applied to the inner electrode surfaces to make them smooth and also to reduce the surface resistivity. In the silicone coated RPCs an efficiency > 90% and time resolution \sim 2 ns (FWHM) have been obtained for both the streamer and the avalanche mode of operation. Before fabrication of detectors the electrical properties such as bulk resistivity and surface resistivity of the electrode materials are measured carefully. Effectiveness of different silicone coating in modifying the surface resistivity was evaluated by an instrument developed for monitoring the I-V curve of a high resistive surface. The results indicate definite correlation of the detector efficiency for the atmospheric muons and the RPC noise rates with the surface resistivity and its variation with the applied bias voltage. It was also found that the surface resistivity varies for different grades of silicone material applied as coating, and the results are found to be consistent with the detector efficiency and noise rate measurements done with these RPCs.Comment: 9 Pages, 6 figure