Impact damage of composite plates

A simple model to study low velocity transverse impact of thin plates made of fiber-reinforced composite material, in particular T300/5208 graphite-epoxy was discussed. This model predicts the coefficient of restitution, which is a measure of the energy absorbed by the target during an impact event. The model is constructed on the assumption that the plate is inextensible in the fiber direction and that the material is incompressible in the z-direction. Such a plate essentially deforms by shear, hence this model neglects bending deformations of the plate. The coefficient of restitution is predicted to increase with large interlaminar shear strength and low transverse shear modulus of the laminate. Predictions are compared with the test results of impacted circular and rectangular clamped plates. Experimentally measured values of the coefficient of restitution are found to agree with the predicted values within a reasonable error

Standard Coupling Unification in SO(10), Hybrid Seesaw Neutrino Mass and Leptogenesis, Dark Matter, and Proton Lifetime Predictions

We discuss gauge coupling unification of the SM descending directly from SO(10) while providing solutions to the three outstanding problems: neutrino masses, dark matter, and the baryon asymmetry of the universe. Conservation of matter parity as gauged discrete symmetry in the model calls for high-scale spontaneous symmetry breaking through ${126}_H$ Higgs representation. This naturally leads to the hybrid seesaw formula for neutrino masses mediated by heavy scalar triplet and right-handed neutrinos. The seesaw formula predicts two distinct patterns of RH$\nu$ masses, one hierarchical and another not so hierarchical (or compact) when fitted with the neutrino oscillation data. Predictions of the baryon asymmetry via leptogenesis are investigated through the decays of both the patterns of RH$\nu$ masses. A complete flavor analysis has been carried out to compute CP-asymmetries and solutions to Boltzmann equations have been utilized to predict the baryon asymmetry. The additional contribution to vertex correction mediated by the heavy left-handed triplet scalar is noted to contribute as dominantly as other Feynman diagrams. We have found successful predictions of the baryon asymmetry for both the patterns of RH$\nu$ masses. The triplet fermionic dark matter at the TeV scale carrying even matter parity is naturally embedded into the non-standard fermionic representation ${45}_F$ of SO(10). In addition to the triplet scalar and the triplet fermion, the model needs a nonstandard color octet fermion of mass $\sim 10^7$ GeV to achieve precision gauge coupling unification. Threshold corrections due to superheavy components of ${126}_H$ and other representations are estimated and found to be substantial. It is noted that the proton life time predicted by the model is accessible to the ongoing and planned experiments over a wide range of parameter space.Comment: 58 pages PDFLATEX, 19 Figures, Revised as suggested by JHEP Revie

Effect of Composition on Optical and Thermoelectric Properties of Microstructured p-type (Bi2Te3)x(Sb2Te3)1 – x Alloys

Semiconducting (Bi2Te3)x(Sb2Te3)1 – x alloys are among the best thermoelectric materials available today near room temperature. This property is largely attributed to compositional variations, resulting in improved figure of merit. Considering this, present study aimed at characterizing the optical and thermoelectric properties of microstructured p-type (Bi2Te3)x(Sb2Te3)1 – x alloys for enhanced thermoelectric efficiency. High performance microstructured p-type (Bi2Te3)x(Sb2Te3)1 – x alloys were prepared by melting technique. The phase, optical band gap, microstructure, carrier type concentration and thermoelectric properties of the prepared alloys were systematically investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, hot probe p-n type tester, four-probe method, κ-probe method and Seebeck coefficient measurement system. The electrical conductivity and Seebeck coefficient were measured in the temperature range 298-473 K to elucidate the Sb content effect on the thermoelectric properties of the p-type (Bi2Te3)x(Sb2Te3)1 – x alloys. The optical band gap decreased with increasing Sb content. Also, with the increase of Sb content, the electrical conductivity increased substantially, the thermal conductivity increased significantly and the Seebeck coefficient decreased marginally, which lead to a great improvement in the thermoelectric figure of merit. The maximum power factor of 3.2 × 10 – 3 Wm – 1K – 2 and figure of merit of 0.72 were obtained at 300 K for the composition of 15 %Bi2Te3-85 %Sb2Te3. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3432

Derivation of water vapour absorption cross-sections in the red region

Absorption spectrum in 436 to 448 nm wavelength region gives NO2 and O3 column densities. This spectrum can also give H2O column density. The spectrum in the range of 655 to 667 nm contains absorption due to NO3 and H2O. Combining the absorption spectra in the wavelength ranges of 436 to 448 and 655 to 667 nm, water vapor absorption cross-sections in this range comes out to be of the order of 2.0 x 10(exp -24) cm(exp -2)

Proton decay and new contribution to neutrino-less double beta decay in SO(10) with low-mass Z-prime boson, observable n-nbar oscillation, lepton flavor violation, and rare kaon decay

Conventionally for observable $n-{\bar n}$ oscillation through Pati-Salam intermediate gauge symmetry in $SO(10)$, the canonical seesaw mechanism is also constrained by $M_R \sim M_C \le 10^6$ GeV which yields light neutrino masses much larger than the neutrino oscillation data. Recently, this difficulty has been evaded via inverse seesaw mechanism, but with proton lifetime far beyond the experimentally accessible limits. In the present work, adopting the view that we may have only a TeV scale $Z^{\prime}$ gauge boson, we show how a class of non-SUSY $SO(10)$ models allow experimentally verifiable proton lifetime and the new contributions to neutrinoless double beta decay in the $W_L-W_L$ channel, lepton flavor violating branching ratios, observable $n-{\bar n}$ oscillation, and lepto-quark gauge boson mediated rare kaon decays. The occurrence of Pati-Salam gauge symmetry with unbroken D-parity and two gauge couplings at the highest intermediate scale guarantees precision unification in such models. This symmetry also ensures vanishing GUT threshold uncertainy on $\sin^2\theta_W$ or on the highest intermediate scale. Although the proton lifetime prediction is brought closer to the ongoing search limits with GUT threshold effects in the minimal model, no such effects are needed in a non-minimal model. We derive a new analytic expression for the $0\nu\beta\beta$ decay half-life and show how the existing experimental limits impose the lower bound on the lightest of the three heavy sterile neutrino masses, $M_{S_1}\ge 14\pm 4$ GeV. We also derive a new lower bound on the lepto-quark gauge boson mass mediating rare kaon decay, $M_{\rm lepto} \ge (1.53{\pm 0.06})\times 10^6$ GeV. The $n-{\bar n}$ mixing times are predicted in the range$\tau_{n-{\bar n}}\simeq 10^8-10^{13}$ sec.Comment: 36 pages Latex, 9 figures and 5 table

Universal Electro-Optical Hybrid Logic Gates

An Electro-Optical Hybrid Logic Gate is defined as a circuit which accepts either electrical or optical signals and produces both electrical and optical signals. This paper explores the feasibility to develop universal hybrid NOR and NAND gates which can be used for implementing any basic gate like AND, OR, or any complex logic function. These hybrid logic gates are proposed and implemented using phototransistors and LEDs. The logic circuits are found to be working satisfactorily for the defined logic levels