Localized canting of spins structure in the spinel oxide system: ZnzTizFe2−x−zCrx−zCoO4

The spinel oxide system Zn_zTi_zFe_2−x−zCr_x−zCoO₄; z=x²; x=0.60, 0.65, 0.70 and 0.80, was studied using neutron diffraction technique, low field DC magnetization measurements (ZFC–FC measurements), magnetic hysterisis, Mössbauer spectroscopy and low field AC susceptibility measurements. All the compositions show significantly less B-site magnetic moments at 10 K temperature derived from neutron diffraction data than the free ions site moments deduced assuming collinear arrangement of spins. This combined with some other features seen in the low temperature neutron diffraction patterns suggest localized canting of spins (LCS) type of magnetic ordering in the present system where a long range order of longitudinal component of moments co-exists along with totally disordered transverse component of moments. The conclusion is also supported by the features seen in the other measurements. The magnetic moments derived from 10 K neutron diffraction data are explained using the LCS approach for different exchange integrals ratios.     

X-ray powder diffraction patterns for certain beta-lactam, tetracycline and macrolide antibiotic drugs.

X-ray powder diffraction (XRD) data for eight beta-lactam viz., ampicillin sodium, ampicillin trihydrate, penicillin G procaine, benzathine penicillin, benzyl penicillin sodium, cefalexin, cefotaxime sodium and ceftriaxone sodium; three tetracyclines viz., doxycycline hydrochloride, oxytetracycline dihydrate and tetracycline hydrochloride; and two macrolide viz., azithromycin and erythromycin estolate antibiotic drugs were obtained using a powder diffractometer. The drugs were scanned from Bragg angles (2theta) of 10 degrees to 70 degrees. The obtained data were tabulated in terms of the lattice spacing (A) and relative line intensities (I/I(I)). This new information may be useful for identifying these drugs from confiscated materials, which has been frequently encountered in forensic laboratories.     

Surface and subsurface stress evaluation in case-carburised steel using high and low frequency magnetic barkhausen emission measurements

The effect of near-surface and subsurface stresses on the magnetic Barkhausen emission (MBE) profile has been studied in case-carburised and tempered En36 steel. The high- and low-frequency MBE measurements were made, on both tensile and compressive sides of the rectangular bar specimens with case-depth of 0.95 mm loaded in cantilever beam, under different stress levels as well as after unloading from different higher stress levels. The high-frequency MBE profile showed a single peak while the low-frequency MBE profile showed two peaks. Under applied elastic stresses, both types of measurement showed increase in MBE under tension and decrease in MBE under compression. But, the MBE profiles measured after unloading from higher stresses showed different behaviour. On the tensile side, the high-frequency MBE profile did not change significantly due to pre-stress. But, in the low-frequency MBE profile, the first peak increases and the second peak decreases with increase in pre-stress. On the compressive side, the peak height of high-frequency MBE profile decreased gradually with increase in pre-stress. The first peak of the low-frequency MBE profile also decreased gradually with increase in pres-stress level. But, the second peak of the low-frequency MBE profile decreased by about 10% at a pre-stress level of −1094 MPa and remained more or less the same even after unloading from −1783 MPa. The MBE behaviour has been correlated to the residual stress (RS)-depth profile measured using X-ray diffraction method. This correlation clearly indicates that the high-frequency MBE reflects only the changes in surface RS level. It does not indicate RS changes occurring at depths >20 μm below the surface. The low-frequency MBE profile reflects the changes in the RS distribution occurring in the near-surface as well as deeper subsurface layers.     

Synthesis and conformation of diethyl 2,3‐diaryltetrahydro‐4,5‐isoxazoledicarboxylates

The microwave assisted synthesis of diethyl 2,3‐diaryltetrahydro‐4,5‐isoxazoledicarboxylates by the cycloaddition of diethyl maleate with appropriate nitrones was carried out. The conformational aspects of the title compounds were investigated by NMR and X‐ray studies and the features are compared with a set of related tetrahydroisoxazoles highlighting the effect of substituents on the conformation of central five mem‐bered ring.     

Foliar application of distillery-spent wash as a liquid fertilizer for betterment of growth ofSorghum vulgare andCajanus cajan

The distillery spent wash contained all necessary elements and biofertilizer microbes (Rhizobia, Azospirilla, Azotobacter, and phosphobacteria) to support the growth of plants. Application of the spent wash, as it is without dilution, did not cause deformities and derangement of plant metabolism. The successful use of distillery spent wash as a liquid fertilizer for augmenting crop productivity in C3 and C4 plants has been demonstrated.     

Stereoselective synthesis of chiral β-disubstituted-β-amino acid derivatives using Pd/In transmetallation cascade processes

A new, highly efficient synthesis of chiral β^2,3-disubstituted-β-amino acid derivatives has been developed, based on an allylation procedure employing allene and a catalytic Pd/In bimetallic process.     

Experimental Study of Thermal Contact Resistance in Hardened Bearing Surfaces

The significance of thermal contact resistance on a bearing steel surface and its application in the analysis of heat flow through layers has been discussed. In the present study, it is considered that the surface roughness and the interface temperature vary to estimate effective thermal conductivity of the bearing model under steady-state and insulated conditions. Surface roughness was considered in the range of 2.37–7.16 μm, and thermal contact properties of the hardened steels were studied under dry and lubricated conditions. These results help to predict temperature distributions of the bearing using SolidWorks2011 (Dassault Systèmes SolidWorks Concord, MA, USA).     

Transformation of Terminal Diols of Cyclic and Acyclic Saccharides to Epoxides and Alkenes by Reaction with Triphenylphosphine,Imidazole and Iodine

ABSTRACT

Reaction of various terminal diols 1,4,6,8-12, derived from cyclic and acyclic monosaccharides, with 2 mol equivalents each of TPP-imidazole-I₂ between -8 °C and 15 °C in THF afforded the corresponding epoxides 2,5,7,13-17, respectively, with 4 mol equivalents each of TPP-imidazole-I₂ in toluene at reflux temperature the starting diols afforded the corresponding alkenes 3,18-24, respectively.     

Exploring the Effect of Bioisosteric Replacement of Carboxamide by a Sulfonamide Moiety on N‐Glycosidic Torsions and Molecular Assembly: Synthesis and X‐ray Crystallographic Investigation of N‐(β‐D‐Glycosyl)sulfonamides as N‐Glycoprotein Linkage Region Analogues

N‐Glycoprotein linkage region constituents, 2‐acetamido‐2‐deoxy‐β‐D ‐glucopyranose (GlcNAc) and asparagine (Asn) are conserved among all the eukaryotes. To gain a better understanding for nature’s choice of GlcNAcβAsn as linkage region constituents and inter‐ and intramolecular carbohydrate–protein interactions, a detailed systemic structural study of the linkage region conformation is essential. Earlier crystallographic studies of several N‐(β‐glycopyranosyl)alkanamides showed that N‐glycosidic torsion, ?_N, is influenced to a larger extent by structural variation in the sugar part than that of the aglycon moiety. To explore the effect of the bioisosteric replacement of a carboxamide group by a sulfonamide moiety on the N‐glycosidic torsions as well as on molecular assembly, several glycosyl methanesulfonamides and glycosyl chloromethanesulfonamides were synthesized as analogues of the N‐glycoprotein linkage region, and crystal structures of seven of these compounds have been solved. A comparative analysis of this series of crystal structures as well as with those of the corresponding alkanamido derivatives revealed that N‐glycosidic torsion, ?_N, does not alter significantly. Methanesulfonamido and chloromethanesulfonamido derivatives of GlcNAc display a different aglycon conformation compared to other sulfonamido analogues. This may be due to the cumulative effect of the direct hydrogen bonding between N1 and O1′ and C? H???O interactions of the aglycon chain, revealing the uniqueness of the GlcNAc as the linkage sugar.