Thermal stresses in a solid weakened by an external circular crack

Linear thermoelastic problems solved for thermal stress and displacement fields in elastic solids weakened by external circular cracks or plane of discontinuit

A new Q-matrix in the Eight-Vertex Model

We construct a $Q$-matrix for the eight-vertex model at roots of unity for crossing parameter $\eta=2mK/L$ with odd $L$, a case for which the existing constructions do not work. The new $Q$-matrix \Q depends as usual on the spectral parameter and also on a free parameter $t$. For $t=0$ \Q has the standard properties. For $t\neq 0$, however, it does not commute with the operator $S$ and not with itself for different values of the spectral parameter. We show that the six-vertex limit of \Q(v,t=iK'/2) exists.Comment: 10 pages section on quasiperiodicity added, typo corrected, published versio

Dynamic nuclear polarization from current-induced electron spin polarization

Current-induced electron spin polarization is shown to produce nuclear hyperpolarization through dynamic nuclear polarization. Saturated fields of several millitesla are generated upon the application of electric field over a timescale of a hundred seconds in InGaAs epilayers and measured using optical Larmor magnetometry. The dependence on temperature, external magnetic field, and applied voltage is investigated. We find an asymmetry in which the saturation nuclear field depends on the relative alignment of the electrically generated spin polarization and the external magnetic field, which we attribute to an interplay between various electron spin dynamical processes.Comment: 5 pages, 4 figure

External elliptical crack in elastic solid

Potential functions for three dimensional problems of infinite elastic solid containing elliptical crac

Mechanical control of spin-orbit splitting in GaAs and InGaAs epilayers

Time-resolved Kerr rotation spectroscopy as a function of pump-probe distance, voltage and magnetic field is used to measure the momentum-dependent spin splitting energies in GaAs and InGaAs epilayers. The strain of the samples can be reproducibly controlled in the cryostat using three- and four-point bending applied with a mechanical vise. We find that the magnitude of the spin splitting increases linearly with applied tension and voltage. A strain-drift diffusion model is used to relate the magnitude of the measured spin-orbit splitting to the amount of strain in the sample.Comment: 4 pages, 5 figure

A proposal for the measurement of Rashba and Dresselhaus spin-orbit interaction strengths in a single sample

We establish an exact analytical treatment for the determination of the strengths of the Rashba and Dresselhaus spin-orbit interactions in a single sample by measuring persistent spin current. A hidden symmetry is exploited in the Hamiltonian to show that the spin current vanishes when the strength of the Dresselhaus interaction becomes equal to the strength of the Rashba term. The results are sustained even in the presence of disorder and thus an experiment in this regard will be challenging.Comment: 5 pages, 5 figure

Simulation of impulsive loading on column using inflatable airbag technique

The purpose of this study was to simulate impulsive loading on columns by an innovative lab-based experimental technique that utilises inflatable airbags. Mild and stainless steel hollow sectioin columns with effective lengths of 955mm and under simply supported condition were used in this study

Pengembangan Produk Jamur Kuping (Auricularia Auricula): Acar dan Keripik

Wood ear mushroom (Auricularia auricula) with its high fiber, springy texture and unique flavor is potential to be developed for high economical value processed food. This research aims to develop wood ear mushroom processed food, which are pickled mushroom and chips. The product development includes optimization of formulation and processing. The pickle was made in two brine concentrations (7,5% and 10%) and packed in Poly Ethylene (PE) plastic cups. During three weeks refrigeration, visual observation, the acidity level, color (using Chromameter CR 400 Konica Minolta) and total counts were measured weekly. For mushroom chips, there were five formulations of coating mixed flour (A: 100% wheat flour; B: 75% wheat flour : 25% rice flour; C: 75% wheat flour : 25% sagoo flour ; D: 50% wheat flour: 25% rice flour: 25% sagoo flour and E: 50% wheat flour : 50% sagoo flour). The chips were measured for the break strength (using Texture Profile Analysis by Loyyd Texture Analyzer), sensory evaluation (using hedonic ranking test) and proximate analysis. The result revealed that the recommended pickled mushroom was P10, which pretreated by soaking in 0.1% citric acid + 0.1% sodium metabisulfite and soaked in 10% brine solution since it has the longest shelf-life (two weeks in the refrigerator). Wood ear mushroom chips D which was coated with wheat flour: rice flour: sagoo flour 50%: 25%: 25% was the most preferred by the panelist

Spatial imaging of the spin Hall effect and current-induced polarization in two-dimensional electron gases

Spin-orbit coupling in semiconductors relates the spin of an electron to its momentum and provides a pathway for electrically initializing and manipulating electron spins for applications in spintronics and spin-based quantum information processing. This coupling can be regulated with quantum confinement in semiconductor heterostructures through band structure engineering. Here we investigate the spin Hall effect and current-induced spin polarization in a two-dimensional electron gas confined in (110) AlGaAs quantum wells using Kerr rotation microscopy. In contrast to previous measurements, the spin Hall profile exhibits complex structure, and the current-induced spin polarization is out-of-plane. The experiments map the strong dependence of the current-induced spin polarization to the crystal axis along which the electric field is applied, reflecting the anisotropy of the spin-orbit interaction. These results reveal opportunities for tuning a spin source using quantum confinement and device engineering in non-magnetic materials.Comment: Accepted for publication (2005