Bounds on the effective thermal conductivity of two-phase systems

The weighted geometric mean of resistors considered for determining the effective thermal conductivityK _E of two-phase systems has been optimised. Solutions of the equations lead to a useful set of bounds. When compared with other bounds the present bounds give the better results in estimating the upper and lower values of the effective thermal conductivity of a two-phase system.     

Determination of rare earths in low grade uranium ores and SRM-rock by instrumental neutron activation analysis

An instrumental neutron activation analysis technique has been developed for simultaneous determination of 10 REE in low grade U/Zr ores and other geological materials. The samples were irradiated with reactor neutrons for 2 min to 8 hrs followed by a cooling of 30 min to 3 weeks. The γ-ray activity was measured with a semi-planar Ge(Li) detector. A precision of 5% has been obtained by the repeated analysis of NBS-SRM. The technique is relatively simple and adaptable on the routine basis.     

Orientational order in liquid crystals exhibited by some binary mixtures of rod-like and bent-core molecules

We report measurements of the temperature variations of the optical birefringence in the nematic (N) and partial bilayer SmA (SmA_d) phases in 4-n-octyloxy 4^′ -cyanobiphenyl made of rod-like (R) molecules and five mixtures of this compound with 1,3-phenylene bis[4-(3-methylbenzoyloxy)] 4^′ -n- dodecylbiphenyl 4^′ -carboxylate, made of bent-core (BC) molecules. The birefringence decreases with the concentration x of the BC molecules but the macroscopic order parameter initially decreases upto 11mol% of BC molecules and subsequently increases with x . This is attributed to the possible formation of polar clusters of BC molecules. Orientation of BC molecules changes between the N and SmA_d phases and the birefringence data in the two phases imply that the kink angle of the BC molecules is ∼ 90^° rather than ∼ 110^° as obtained from calculations which minimize the energy of the molecule. IR spectroscopic measurements on the mixture with 11mol% of BC molecules have been used to estimate the molecular order parameter S of the R molecules, and to provide additional support for a relatively small kink angle of BC molecules.     

Charged Analogue of Whittaker’s Interior Solution

Charged analogue of Whittaker’s interior solution is derived which possess constant gravitational mass density (ρ+3p). The solution joins smoothly to Nordstörm solution at the pressure free interface. The solution has increasing energy density away from the center which is unphysical however such model can very well represent the situations when density undergoes abrupt changes during the tug of war between the gravitational attraction and electrostatic repulsion.     

Closed-Range Composition Operators on {\mathbb{A}^2} and the Bloch Space

For any analytic self-map j{\varphi} of {z : |z| <  1} we give four separate conditions, each of which is necessary and sufficient for the composition operator C_j{C_{\varphi}} to be closed-range on the Bloch space B{\mathcal{B}} . Among these conditions are some that appear in the literature, where we provide new proofs. We further show that if C_j{C_{\varphi}} is closed-range on the Bergman space \mathbbA²{\mathbb{A}^2} , then it is closed-range on B{\mathcal{B}} , but that the converse of this fails with a vengeance. Our analysis involves an extension of the Julia-Carathéodory Theorem.     

Optimal execution with weighted impact functions: a quadratic programming approach

In this paper, we develop optimal trading strategies for a risk averse investor by minimizing the expected cost and the risk of execution. Here we consider a law of motion for price which uses a convex combination of temporary and permanent market impact. In the special case of unconstrained problem for a risk neutral investor, we obtain a closed form solution for optimal trading strategies by using dynamic programming. For a general problem, we use a quadratic programming approach to get approximate dynamic optimal trading strategies. Further, numerical examples of optimal execution strategies are provided for illustration purposes.     

WEB‐spline based mesh‐free finite element analysis for the heat equation and the time‐dependent Navier–Stokes equation: A survey

In this article, we give some numerical techniques and error estimates using web‐spline based mesh‐free finite element method for the heat equation and the time‐dependent Navier–Stokes equations on bounded domains. The web‐spline method uses weighted extended B‐splines on a regular grid as basis functions and does not require any grid generation. We demonstrate the method by providing numerical results for the Poisson's and stationary Stokes equation. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013     

A New Class of Stabilized WEB-Spline-Based Mesh-Free Finite Elements for the Approximation of Maxwell Equations

The objective of this article is to discuss the existence and the uniqueness of a weighted extended B-spline-(WEB-spline) based discrete solution for the Maxwell equations in low frequency limit. The domain is composed of insulating and conducting regions. This problem has saddle point structure where the electric field in insulating region is the Lagrange multiplier that forces curl-free constraint on the magnetic field.     

Defect-Induced intrinsic magnetism in wide-gap III nitrides

Cation-vacancy induced intrinsic magnetism in GaN and BN is investigated by employing density-functional theory based electronic structure methods. The strong localization of defect states favors spontaneous spin polarization and local moment formation. A neutral cation vacancy in GaN or BN leads to the formation of a net moment of 3 muB with a spin-polarization energy of about 0.5 eV at the low density limit. The extended tails of defect wave functions, on the other hand, mediate surprisingly long-range magnetic interactions between the defect-induced moments. This duality of defect states suggests the existence of defect-induced or mediated collective magnetism in these otherwise nonmagnetic sp systems.     

1H-NMR-Based Metabolomics: An Integrated Approach for the Detection of the Adulteration in Chicken,Chevon, Beef and Donkey Meat

Meat is a rich source of energy that provides high-value animal protein, fats, vitamins, minerals and trace amounts of carbohydrates. Globally, different types of meats are consumed to fulfill nutritional requirements. However, the increasing burden on the livestock industry has triggered the mixing of high-price meat species with low-quality/-price meat. This work aimed to differentiate different meat samples on the basis of metabolites. The metabolic difference between various meat samples was investigated through Nuclear Magnetic Resonance spectroscopy coupled with multivariate data analysis approaches like principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA). In total, 37 metabolites were identified in the gluteal muscle tissues of cow, goat, donkey and chicken using ¹H-NMR spectroscopy. PCA was found unable to completely differentiate between meat types, whereas OPLS-DA showed an apparent separation and successfully differentiated samples from all four types of meat. Lactate, creatine, choline, acetate, leucine, isoleucine, valine, formate, carnitine, glutamate, 3-hydroxybutyrate and α-mannose were found as the major discriminating metabolites between white (chicken) and red meat (chevon, beef and donkey). However, inosine, lactate, uracil, carnosine, format, pyruvate, carnitine, creatine and acetate were found responsible for differentiating chevon, beef and donkey meat. The relative quantification of differentiating metabolites was performed using one-way ANOVA and Tukey test. Our results showed that NMR-based metabolomics is a powerful tool for the identification of novel signatures (potential biomarkers) to characterize meats from different sources and could potentially be used for quality control purposes in order to differentiate different meat types.