Barut-Girardello Coherent States for Nonlinear Oscillator with Position-Dependent Mass

Using ladder operators for the non-linear oscillator with position-dependent effective mass, realization of the dynamic group SU(1,1) is presented. Keeping in view the algebraic structure of the non-linear oscillator, coherent states are constructed using Barut-Girardello formalism and their basic properties are discussed. Furthermore, the statistical properties of these states are investigated by means of Mandel parameter and second order correlation function. Moreover, it is shown that in the harmonic limit, all the results obtained for the non-linear oscillator with spatially varying mass reduce to corresponding results of the linear oscillator with constant mass.     

First Principles Investigation of Fluorine Based Strontium Series of Perovskites

Density functional theory is used to explore structural, elastic, and mechanical properties of SrLiF₃, SrNaF₃, SrKF₃ and SrRbF₃ fluoroperovskite compounds by means of an ab-initio Full Potential-Linearized Augmented Plane Wave (FP-LAPW) method. Several lattice parameters are employed to obtain accurate equilibrium volume (V_o). The resultant quantities include ground state energy, elastic constants, shear modulus, bulk modulus, young's modulus, cauchy's pressure, poisson's ratio, shear constant, ratio of elastic anisotropy factor, kleinman's parameter, melting temperature, and lame's coefficient. The calculated structural parameters via DFT as well as analytical methods are found to be consistent with experimental findings. Chemical bonding is used to investigate corresponding chemical trends which authenticate combination of covalent-ionic behavior. Furthermore electron density plots as well as elastic and mechanical properties are reported for the first time which reveals that fluorine based strontium series of perovskites are mechanically stable and posses weak resistance towards shear deformation as compared to resistance towards unidirectional compression while brittleness and ionic behavior is dominated in them which decreases from SrLiF₃ to SrRbF₃. Calculated cauchy's pressure, poisson's ratio and B/G ratio also proves ionic nature in these compounds. The present methodology represents an effective and influential approach to calculate the whole set of elastic and mechanical parameters which would support to understand various physical phenomena and empower device engineers for implementing these materials in numerous applications.     

On the second fundamental problem of combined free and forced convection through vertical noncircular ducts

Analysis of combined free and forced convection through vertical noncircular ducts is carried out using a variational technique. Fully developed flow with uniform axial heat input and uniform peripheral heat flux is assumed. All fluid properties are considered invariant with temperature except the variation of density in the buoyancy term of the equation of motion. The condition of uniform peripheral heat flux is utilized in deriving the variational expression. This procedure releases the thermal boundary condition from satisfying exactly the condition at the wall. A finite-difference procedure is carried out. For pure forced convection case, a particularly simple variational expression is presented. Nusselt numbers for combined free and forced convection are computed for rectangular, rhombic and elliptical ducts. An exact solution is presented for laminar forced convection through elliptic ducts. Variational results are in agreement with this exact solution. The present results are compared with those in the published literature wherever possible, and good agreement is obtained.     

Novel sesterterpenes from Leucosceptrum canum of nepalese origin

Two novel sesterterpenoids, leucosesterterpenone (1) and leucosesterlactone (2), with novel skeleta were isolated from the hexane extract of the medicinal plant, Leucosceptrum canum. Their structures were established by the analysis of NMR data and the single-crystal X-ray diffraction of compound 1. Compounds 1 and 2 were found to exhibit activity against prolylendopeptidase (PEP).     

Association study of the angiotensin-converting enzyme (ACE) gene G2350A dimorphism with myocardial infarction

The angiotensin converting enzyme (ACE) is a strong candidate gene for myocardial infarction (MI). Insertion-deletion dimorphism in intron 16 of this gene has been inconclusively found to be associated with it. Several new polymorphisms in the ACE gene have been identified and among these, a dimorphism in exon 17, ACE G2350A, has a significant effect on plasma ACE concentrations. To assess the value of genotyping the ACE G2350A dimorphism in a genetically homogeneous population, we carried out a case-control study of dimorphism G2350A for a putative association with MI among Pakistani nationals. We investigated a sample population of 370 Pakistanis, comprising 163 controls, and 207 patients with clinical diagnosis of acute MI (AMI). ACE G2350A alleles were visualized by assays based on polymerase chain reaction and restriction endonuclease analysis. Frequencies of G alleles were 0.68 among controls and 0.72 among AMI patients. The ACE G2350A dimorphism showed no significant association with MI (chi2 = 0.90, 2 df, P = 0.64), plasma levels of homocysteine (P = 0.52) or with serum levels of folate (P = 0.299). The results indicate that ACE G2350A polymorphism is not associated with risk of myocardial infarction in the Pakistani population investigated here.     

Integrated production scheduling in large-scale flexible electronic parts manufacturing

This study reports the development of a production scheduling system for the integrated management of production in large-scale, high-volume electronic assembly lines. The development of the system incorporates control and planning considerations by addressing the interaction of various subsystems. Stochastic and deterministic aspects of the problem environment are appropriately handled via relevant simulation and analytic models. By effecting a hierarchical breakdown of the problem environment, the system produces information used in practical decision making for production planning and scheduling. Procedures used encompass and address considerations for management of work-in-process, optimization of the various subsystems' performance, minimization of setup time effect, and inventory carrying costs.     

4-(5-nonyl)pyridine extraction of platinum from different aqueous solutions

The partition of tracer-level (<10^?7 mole/l) platinum between various 4-(5-nonyl)-pyridine phases and aqueous nitric, hydrochloric, and sulphuric acid phases has been studied radiometrically as a function of the amine and acid concentrations. The effects of saltingout agents and some anions on the extraction of the metal are reported. The extraction data is compared with that of gold and conditions are established for the separation of daughter¹⁹⁹Au from neutron irradiated platinum. The distribution coefficients of various metal ions are given for the 4-(5-nonyl)pyridine-10M HCl system and their factors for separation from platinum estimated.     

Iron Carbonyls in Organic Synthesis,I. Iron Pentacarbonyl Induced Decomposition and Transfer Hydrogenation of Aryl Azides to Substituted Ureas

Iron pentacarbonyl catalyzes smooth decomposition of aryl azides in the presence of acetic acid to afford good (70–90°) yields of the corresponding disubstituted ureas. Possible and alternative reaction mechanism pathways are discussed.     

Raman scattering and optical absorption in S2N2 and partially polymerized S2N2 films

Raman scattering and optical absorption measurements between 0.5 and 5.0 eV on crystalline films of S₂N₂ and partly polymerized S₂N₂ have been made for the first time. The Raman active molecular and librational phonons have been observed and assigned. The Raman spectra of partly polymerized S₂N₂ show the appearance of weak scattering at 635 cm⁻¹ and appreciable broadening of the librational phonon peaks. Optical absorption maxima occur at 4.0 and 4.7 eV in pure S₂N₂ at 14 K, while absorptions at 0.86, 1.1 and 4 eV evolve with increasing polymerization.     

Studies on the sol-gel transformation of silicic acid sol in presence of dyes

The influence of dyes on the gelation of silicic acid sol has been studied with the help of viscometric and pH metric methods. The results indicate that the time of gelation decreases in presence of basic dyes and increases with acid dyes. It has also been found that methylene blue is adsorbed by replacement of H⁺ ions by the big cation of the dye followed by a possible combination between S of the dye and OH of the silanol group of silicic acid. The results on pH variations during gelation support this viewpoint. Similar results have been obtained with malachite green. The interaction of alizarin sulphonic acid with silicid acid is explained in terms of compound formation between the silanol and the phenolic groups while methyl orange undergoes orientation to quinonoid structure in presence of silicic acid. Positive adsorption is found to take place in all cases except methyl orange which is negatively adsorbed.