Observation of transverse polarization asymmetries of charged pion pairs in e+e- annihilation near √s = 10.58 GeV

The interference fragmentation function translates the fragmentation of a quark with a transverse projection of the spin into an azimuthal asymmetry of two final-state hadrons. In e(+)e(-) annihilation the product of two interference fragmentation functions is measured. We report nonzero asymmetries for pairs of charge-ordered π(+)π(-) pairs, which indicate a significant interference fragmentation function in this channel. The results are obtained from a 672 fb(-1) data sample that contains 711 × 10(6) π(+)π(-) pairs and was collected at and near the Υ(4S) resonance, with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider.     

Two-dimensional cell parameters measurement of nematic liquid crystal using optical interferometry and Fourier transform fringe analysis technique

We report a method for the measurement of nematic liquid crystal (NLC) cell parameters i.e., switching voltage, birefringence, retardation, dielectric anisotropy, average tilt angle and change in refractive index with applied DC voltage to LC material. The proposed method is based on optical interferometry and Fourier transform fringe analysis technique, in which we obtain 2-dimensional (2D) phase map of the interferograms as a function of applied voltage. Mach-Zehnder interferometer (MZI) was used for the study of cell parameters and interferograms were recorded at different applied DC voltages to NLC cell using CCD camera. From the phase map, 2D-refractive index distribution of the LC cell with applied voltage was reconstructed. Analytical equations are derived based on optical interferometry and then solved to obtain cell parameters. The present method is fast and can give 2D-cell parameters from only two quick interferograms.     

Systematic evaluation of a few proline derivatives as catalysts for a direct aldol reaction

A series of pyrrolidine derivatives were prepared and examined as catalysts for an aldol reaction. Structural variations in these molecules involved altering the sterics at the α-position, the position of the carbonyl group, and the acidities of the hydrogen bonding sites. The effect of these factors on catalytic activity and enantioselectivity was studied. The experimental results revealed that additional sterics at the α-position were detrimental. However, no correlation was found between the catalytic activity and N–H acidity.     

Synthesis of Some New Dihydropyrimidines by Iodine as a Catalyst at Ambient Temperature and Evaluation of Their Biological Activity

An improved method for the synthesis of some new dihydropyrimidines from aromatic aldehydes, 1,3‐dicarbonyl compounds, and thiourea with significant enhancement in reaction rates, short reaction time (4–6 h), good to excellent yields (70–93%), and ambient temperature using molecular iodine as catalyst is described. The biological evaluation revealed that the newly synthesized compounds 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j and 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i , 7j exhibited good antimicrobial activity and moderate antimycobacterial activity against Mycobacterium tuberculosis H₃₇RV.     

A hybrid FVM–LBM method for single and multi‐fluid compressible flow problems

The lattice Boltzmann method (LBM) has established itself as an alternative approach to solve the fluid flow equations. In this work we combine LBM with the conventional finite volume method (FVM), and propose a non‐iterative hybrid method for the simulation of compressible flows. LBM is used to calculate the inter‐cell face fluxes and FVM is used to calculate the node parameters. The hybrid method is benchmarked for several one‐dimensional and two‐dimensional test cases. The results obtained by the hybrid method show a steeper and more accurate shock profile as compared with the results obtained by the widely used Godunov scheme or by a representative flux vector splitting scheme. Additional features of the proposed scheme are that it can be implemented on a non‐uniform grid, study of multi‐fluid problems is possible, and it is easily extendable to multi‐dimensions. These features have been demonstrated in this work. The proposed method is therefore robust and can possibly be applied to a variety of compressible flow situations. Copyright © 2009 John Wiley & Sons, Ltd.     

Investigation of the effect of drying and refining on the fiber–fiber shear bond strength measured using tensile fracture line analysis of sheets weakened by acid gas exposure

No reliable method exists for measuring the cellulose fiber–fiber shear bond strength in paper. This paper reports a simple method for measuring the fiber–fiber shear bond strength by weakening the fibers independently of the bonds in a sheet of paper, using acid vapor, until all the fibers break across the fracture line. The bond strength is then calculated from the fiber strength, as measured by the zero span test, at the point where the fibers first are weakened such that they all break. The method was used to calculate the average bond strength of handsheets made out of two different pulps. The first pulp was a never dried, 60% yield, unbleached radiata pine. The bond strength was 25.0 ± 3.3 MPa. Drying the fibers before reslushing and making sheets reduced the bond strength by up to 33%, with the reduction depending on the severity of the drying treatment. The second pulp was a bleached dried softwood kraft and was used to investigate the effect of low consistency refining on bond strength. The bond strength increased from 13.7 ± 1.0 MPa for the sheets made from the unrefined pulp to 37.0 ± 1.0 MPa, for the sheets made from the most heavily refined pulp. The bond strength measurements are considerably higher than previous literature estimates for the shear bond strength. The causes for the discrepancy include stress concentrations in tests of single fiber–fiber bonds.     

Temperature dependent small-angle neutron scattering of CTABr—magnetic fluid emulsion

Small-angle neutron scattering studies have been carried out to check the structural integrity of citryltrimethylammonium bromide (CTABr) micelles in a magnetic fluid for different magnetic fluid concentrations at two different temperatures 303 and 333 K. It is found that the CTABr micelles grow with increasing magnetic fluid concentration and there is a decrease in the micellar size with increase in temperature.     

Microwave‐assisted synthesis,characterization, biotoxicity and antispermatogenic activity of some antimony(III) complexes with N∩O and N∩S donor ligands

New series of phenylantimony chloride and antimony chloride with Schiff base ligands, L¹H and L²H having N^∩S and N^∩O donor systems were synthesized under microwave irradiation using a domestic microwave oven. The reaction time was brought down from hours to a few seconds with improved yield as compared with conventional heating. All the ligands and their antimony(III) derivatives were characterized on the basis of microanalysis, elemental analyses, molecular weight determinations and spectral studies including IR, NMR (¹H and ¹³C) and electronic spectral studies. A distorted trigonal bipyramidal and pseudo‐octahedral geometry around the antimony atom was tentatively proposed for these derivatives. The compounds were screened in vitro against bacteria and fungi to test their antimicrobial property and in vivo in male albino rats to test their antifertility properties. The treatment with the ligands and their phenylantimony derivatives at dose levels of 20 mg per rat per day did not cause any significant change in body weight, but a significant reduction in the weights of reproductive organs was observed. Arrest of spermatogenesis was noted at various stages with production of primary spermatocytes (preleptotene and pachytene), secondary spermatocytes and step‐19 spermatids found to be decreased. Biochemical parameters of tissues, i.e. protein, sialic acid, cholesterol content of testes and seminal vesicular fructose also showed significant reduction. Further, the serum testosterone concentrations were also decreased after treatment with ligands and their antimony(III) derivatives. Copyright © 2008 John Wiley & Sons, Ltd.     

On the occurrence of naked singularity in spherically symmetric gravitational collapse

Generalizing earlier results of [1], we analyze here the spherically symmetric gravitational collapse of a matter cloud with a general form of matter for the formation of a naked singularity. It is shown that this is related basically to the choice of initial data to the Einstein field equations, and would therefore occur in generic situations from regular initial data within the general context considered here, subject to the matter satisfying the weak energy condition. The condition on initial data which leads to the formation of black hole is also characterized.