Scattering of Carriers by Charged Dislocations in Semiconductors

The scattering of carriers by charged dislocations in semiconductors is studied within the framework of the linearized Boltzmann transport theory with an emphasis on examining consequences of the extreme anisotropy of the scattering potential. A new closed-form approximate expression for the carrier mobility valid for all temperatures is proposed. The ratios of quantum and transport scattering times are evaluated after averaging over the anisotropy in the relaxation time. The value of the Hall scattering factor computed for charged dislocation scattering indicates that there may be a factor of two error in the experimental mobility estimates using the Hall data. An expression for the resistivity tensor when the dislocations are tilted with respect to the plane of transport is derived. Finally an expression for the isotropic relaxation time is derived when the dislocations are located within the sample with a uniform angular distribution.Comment: 3 figure

School Environment and Locus of Control in Relation to Job Satisfaction among School Teachers – A Study from Indian Perspective

AbstractThe purpose of this study is to explore different patterns of relationship of job satisfaction with school environment and locus of control in different groups of school teachers selected from different school of Kolkata, India. Another objective is to see whether there any demographic variable which play any role on the job satisfaction of the teachers. 160 data were collected from the school teachers of Kolkata, using Revised School-Level Environment Questionnaire, Rotter Locus of control scale and Teacher job satisfaction questionnaire. Results showed that job satisfaction is significantly correlated with different domains of school environment and locus of control. Stepwise regression analysis indicated that job satisfaction can be significantly predicted by locus of control and maximum domains of school environment. This study highlighted a vital impact of school environment and locus of control on job satisfaction

Some new observations for the Georgi-Machacek scenario with triplet Higgs

The Georgi-Machacek model, introducing a complex and a real scalar triplet as additional components of the electroweak symmetry breaking sector, enables substantial triplet contributions to the weak gauge boson masses, subject to the equality of the complex and the real triplet vacuum expectation values (vev) via a custodial SU(2) symmetry. We present an updated set of constraints on this scenario, from collider data (including those from 137/139~fb$^{-1}$ of luminosity at the Large Hadron Collider), available data on the 125-GeV scalar, indirect limits and also theoretical restrictions from vacuum stability and unitarity. It is found that some bounds get relaxed, and the phenomenological potential of the scenario is more diverse, if the doubly charged scalar in the spectrum can decay not only into two like-sign $W$'s but also into one or two singly charged scalars. Other interesting features are noticed in a general approach, such as substantial $\gamma\gamma$ and $Z\gamma$ branching ratios of the additional custodial singlet scalar, and appreciable strength of the trilinear interaction of a charged scalar, the $W$ and the $Z$. Finally,, we take into account the possibility of custodial SU(2) breaking, resulting in inequality of the real and the complex scalar vevs which too in principle may allow large triplet contribution to weak boson masses. Illustrative numerical results on the modified limits and predictions are presented, once more taking into account all the constraints mentioned above.Comment: 17 pages, 9 figure

Investigating the role of amides on the textural and optical properties of mesoporous-nanostructured theta-Al2O3

Mesoporous-nanostructured theta-Al2O3 was synthesized by an autoclaving technique using different amides i.e., formamide (F), dimethyl formamide (DMF) and diethyl formamide (DEF) at 150 degrees C/24 h followed by calcination at 1000 degrees C. Crystallization and structural behaviour of the as-synthesized materials were characterized by X-ray diffraction and Fourier transform infrared spectroscopy. The porosity study was carried out by N-2 adsorption-desorption (BET) technique. Microstructural features were measured by transmission electron microscopy (TEM). The amide-based solvents played a deliberate role in microstructural and textural features of theta-Al2O3. The DMF-based solvent showed an enhanced surface area of 158 m(2) g(-1). The as-prepared theta-Al2O3 rendered a nano-sheet, nano-rod and nano-flake like morphology for F, DMF and DEF derived products, respectively. From the UV-Vis spectroscopic measurement, the estimated band-gap of theta-Al2O3 was found to be 5.16-5.40eV. Photoluminescence investigation further revealed blue emission particularly for excitation at a wavelength of 252 nm. A DMF-derived sample rendered the lowest band gap due to its smaller crystallite size and higher surface area compared to that of F- and DEF-derived samples

Environmental change and migration from Indian Sundarban : the need for an adaptation policy

PowerPoint presentationThe presentation focuses on climate change and forced migration patterns in vulnerable areas of Bangladesh, factoring in changes in sea surface temperature (SST), sea level rise, monsoon rainfall and events such as cyclones. Thousands of island residents have been displaced due to disappearance of land and coastal erosion. Environmental degradation has led to population migrations of 60,000 people - with women, infirm people and children often left behind

Rapid template-free synthesis of an air-stable hierarchical copper nanoassembly and its use as a reusable catalyst for 4-nitrophenol reduction

A hierarchical copper nanoassembly was synthesized by one-pot solvothermal treatment at 150 degrees C for 2 h in the presence of copper nitrate, formamide and water. The product exhibited phase pure hierarchical Cu microspheroids (2-7 mu m) comprising a nanorod (50-100 nm) assembly. The Cu microspheroids showed excellent air-stability, antioxidative properties and catalytic reduction of p-nitrophenol

Nil-extensions of completely simple semirings

A semiring S is said to be a quasi completely regular semiring if for any a ∈ S there exists a positive integer n such that na is completely regular. The present paper is devoted to the study of completely Archimedean semirings. We show that a semiring S is a completely Archimedean semiring if and only if it is a nil-extension of a completely simple semiring. This result extends the crucial structure theorem of completely Archimedean semigroup

Agricultural productivity, household poverty and migration in the Indian Sundarban Delta

Deltas are highly sensitive to erosion, flooding, and salinization with consequential agricultural productivity losses and out-migration, which is a preferred adaptive measure for the inhabitants of deltaic islands. This study investigates the associations between agricultural productivity decrease, household poverty and the probability of out-migration in the Indian Sundarban Delta (ISD). Using newly collected survey data from randomly selected households within the ISD, we analysed these relationships by means of descriptive statistics and regression modeling. Results suggest the significant positive association between a decrease in agricultural productivity and out-migration. The results further show that ceteris paribus, out-migration is negatively associated with household poverty, which is likely to be explained by the effect of remittances. The results yield important policy implications at the local level and can contribute to the progress towards sustainable livelihoods in these deltaic islands