Showing papers by "Jadavpur University published in 1983"
TL;DR: In this paper, the incorporation of polyesteramide polyol (PEAP) resins as interfacila agents has been found to significantly improcve the mechanical properties of jute fiber composites.
Abstract: Polyesteramide polyols have been synthesized by melt condenstion using a mixture of alkanolamines, polyethylene glycols, and dicarboxylic acids/anhydrieds, and the behavior or resin samples as interfacrial agents in unidirectional as well as random composites of jute/epoxy and jute/polyester has been evaluated. Mechanical properties of these composties with or without interfacial agents have been determined along with the effect of water uptake on such properties. The incorporation of polyesteramide polyol (PEAP) resins as interfacila agents has been found to significantly improcve the mechanical properties of jute fiber composites. It has also been found that increasing the hydroxyl value of PEAP results in a better bonding of the composities up to a certain optimum limit of hydroxyl value beyond which the molecular weight of the interfacila agent as well as its bonding strenght decreases. Use of PEAP resin of optimum hydroxyl value and molecular weight also significantly improves the water resistance capacities of jute/epoxy composites.
51 citations
TL;DR: In this paper, the radial vertical electrical sounding (VES) method was used to understand the behavior of rock fracturing at shallow depths in an area of Purulia district, West Bengal, India.
44 citations
36 citations
TL;DR: Weight of the spleen and the splenic cell count decreased significantly in ochratoxin A and citrinin treated mice, and calcium concentration in the serum of toxin treated mice also was decreased significantly.
32 citations
TL;DR: In this paper, the Darboux-Baklund transformation for the differential-difference nonlinear Schrodinger equation is deduced and it is observed that it is also possible to derive the analogue of the usual Backlund transformation giving the direct connection between the two sets of the old and new nonlinear field variables.
Abstract: Darboux-Baklund transformation for the differential-difference nonlinear Schrodinger equation is deduced. It is observed that it is also possible to derive the analogue of the usual Backlund transformation giving the direct connection between the two sets of the old and new nonlinear field variables, from the Darboux-Backlund itself. Also, it is seen that the different polynomial dependence of the B matrix on the eigenvalue parameter gives rise to various kinds of Backlund transformations — a phenomena not encountered in the usual derivation of the Backlund transformation.
29 citations
TL;DR: In this paper, the results indicate that the di-n-butyltin(IV) bis(hydroxylaminates) have distored trans-octahedral structures, whereas the diphenyltin-IV bis (hydroxyaminates) and tripheny-ltin (IV) hydroxylaminates are cis-Octahedral and trigonal bipyramidal, respectively.
28 citations
TL;DR: In this article, an active current conveyor (CC II)-RC realisation of a floating admittance function corresponding to an ideal FDNR element is reported, which has the following advantages: (i) use of only two capacitors and a resistor; (ii) extremely low active sensitivities; (iii) single-resistor tunability of D; and (iv) no design constraint involving component matching.
Abstract: A novel active current conveyor (CC II)-RC realisation of a floating admittance function Y(s) = s2D corresponding to an ideal FDNR element is reported. The scheme has the following advantages: (i) use of only two capacitors and a resistor; (ii) extremely low active sensitivities; (iii) single-resistor tunability of D; (iv) no design constraint involving component matching; (v) realisability of ideal FDNR even with nonideal CC II devices.
26 citations
TL;DR: The photogalvanic effect in phenosafranine-EDTA aqueous system has been studied in deoxygenated solutions using platinum electrodes for both chambers, illuminated and dark, at different temperatures as mentioned in this paper.
24 citations
TL;DR: In this paper, the competence contrast between the boudin and the host material was analyzed and a set of criteria was formulated to identify structures formed by superposed deformations and to give an approximate idea of the competence difference between the Boudin between the host rock and the material during the second deformation.
23 citations
TL;DR: In this article, a theoretical analysis of circular microstrip antenna on a ferrimagnetic substrate predicts significantly reduced resonant radii and improved bandwidth as compared to those of similar antennas built on purely dielectric substrates, when operated in the lower range of UHF.
Abstract: A theoretical analysis of circular microstrip antenna on a ferrimagnetic substrate predicts significantly reduced resonant radii and improved bandwidth as compared to those of similar antennas built on purely dielectric substrates, when operated in the lower range of UHF. The impedance characteristics, return loss, and radiation pattern studied experimentally for antennas built upon a typical ferrite substrate are found to be in good agreement qualitatively with the theoretical results.
20 citations
TL;DR: In this paper, the intensity-induced frequency shift and precessional frequency of two strong circularly polarized waves are derived in a magnetized plasma, and an unexpected feature in the low-frequency limit of a magnetohydrodynamic Alfv\'en wave is that the ion velocity is comparable to the velocity of light in the presence of a static magnetic field.
Abstract: Intensity-induced frequency shift and precessional frequency of two strong circularly polarized waves are derived in a magnetized plasma. An unexpected feature in the low-frequency limit of a magnetohydrodynamic Alfv\'en wave is that the ion velocity is comparable to the velocity of light in the presence of a static magnetic field. This process may be useful in the astrophysical energy-transfer studies and in the experiment with ion---laser-induced plasma.
TL;DR: In this paper, the variation of voltage standing-wave ratio (VSWR) with frequency for microstrip antennas on stepped and wedge-shaped dielectric-substrates is measured for a band of frequencies, and is compared with those of an equivalent rectangular microstrip resonator.
Abstract: The variation of voltage standing-wave ratio (VSWR) with frequency for microstrip antennas on stepped and wedge-shaped dielectric-substrates is measured for a band of frequencies, and is compared with those of an equivalent rectangular microstrip resonator. The results indicate a considerable improvement in bandwidth.
TL;DR: In this paper, a novel RC-sinewave oscillator configuration using the differential voltage controlled current source (DVCCS) active element is proposed, which has only two resistors and two grounded capacitors.
Abstract: A novel RC-sinewave oscillator configuration using the differential voltage controlled current source (DVCCS) active element is proposed. It has only two resistors and two grounded capacitors. The oscillation frequency can be tuned independently by one resistor at low sensitivities. The circuit has an additional capability of realising active lossless grounded inductors at appropriate ports if any of the capacitors is open-circuited.
TL;DR: In this paper, the energy and entropy of activations were investigated in terms of the probable formation of intermediate Au(lI) in the UV region at different temperatures, and the results were interpreted in terms for the probability of the intermediate Au (lI).
TL;DR: In this article, an expression for temperature dependent packing density is obtained and it is shown that this temperature dependent density can account the temperature dependence of structure factor, self-diffusion coefficient, and shear viscosity with good accuracy.
Abstract: An expression for temperature dependent packing density is obtained and it is shown that this temperature dependent packing density can account the temperature dependence of structure factor, self-diffusion coefficient, and shear viscosity with good accuracy. Other observations at higher temperatures also confirm this procedure.
Ein Ausdruck fur die temperaturabhangige Packungsdichte wird erhalten, und es wird gezeigt, das diese temperatur abhangige Packungsdichte die Temperaturabhangigkeit des Strukturfaktors, des Selbstdiffusionskoeffizienten und der Scherviskositat mit groser Genauigkeit erklaren kann. Andere Beobachtungen bei hoheren Temperaturen bestatigen ebenfalls dieses Verfahren.
TL;DR: In this article, a statistical model for baryons was suggested leading to an analytical expression for the square modulus ∥ψ(r)∥2 of baryon wavefunctions, which is not only free of constituent quark masses but also devoid of the interaction parameters of the effective linear potential in which a quark moves.
TL;DR: In this paper, the binding ratio of SDS to BSA in the bulk phase and at the aluminawater interface respectively under identical situation have been compared at various values of the equilibrium bulk concentrations (C s t ) of the surfactant in solution.
Abstract: Mutual adsorption of bovine serum albumin (BSA) and sodium dodecyl sulphate (SDS) at the alumina-water interface has been determined as functions of protein and detergent concentrations, ionic strength, pH and temperature of the aqueous medium. The extgent of adsorption decreases with increase of temperature. The isotherm with respect to the adsorption of protein at a fixed total concentration (C s t ) of the surfactant is S-shaped in character. The limiting value of the protein adsorption decreases with increase of C s/t. The study of adsorption at serveral values of pH and ionic strength of the medium indicates that the mutual interactions of BSA and SDS with alumina interface are significantly controlled byt ehe electrostatic effect. At a given value of C s t , extent of adsorption (Γ S) at first decreases with increase of the adsorption (Γ p) of BSA due to the competitive interaction process whereas Γ S increases with increases of Γ p in the relatively higher range of the adsorption of protein as a result of the increase of the mutual interaction of BSA and SDS at the interface. The binding ratio of SDS to BSA in the bulk phase and at the aluminawater interface respectively under identical situation have been compared at various values of the equilibrium bulk concentrations (C s) of the surfactant in solution. At low values of C s, these ratios in the two phases are of comparable order in magnitude. However, at high values of C s, the binding ratio at the interface increases enormously due to the massive cooperative interaction even though the value of this ratio in the bulk remains low.
TL;DR: In this paper, the reduction and subsequent nitrosylation of ReOi using NH2OHHCI and NCS- in an alkaline medium was described, as well as the direct reductive nitro-sylation using NH 2OHHCl and N- 3 as evidenced by synthesizing the complex ion [Re(NO)(N3)3H2O]- and its 1,10-phenanthroline and 2,2′-bipyridine derivatives from an aqueous-aerobic medium.
Abstract: Reductive nitrosylation of ReO- 4 by any of the known nitrosylating agents1 and subsequent synthesis of rhenium nitrosyl derivatives have not yet been reported The known nitrosyl compounds of this metal are very few and were prepared from low valent rhenium compounds (cyano, chloro or carbonyl complexes) by the treatment with HNO3 23 or NO4,5 or NOX6 We have recently reported7 the reduction and subsequent nitrosylation of ReOi using NH2OHHCI and NCS- in alkaline medium Herein is described the direct reductive nitrosylation of ReO- 4 using NH2OHHCl and N- 3 as evidenced by synthesing the complex ion [Re(NO)(N3)3H2O]- and its 1,10-phenanthroline and 2,2′-bipyridine derivatives from an aqueous-aerobic medium It may be mentioned that azido nitrosyl complexes of any metal are extremely rare (only one is known)6
TL;DR: For GaAs channels having lengths of 0.1, 0.5, 1, and 20 μm, the maximum steady-state velocity increases with decrease in the length and may be as high as 5.4×107 cm/s as mentioned in this paper.
Abstract: Transient velocity-field characteristics have been computed for GaAs channels having lengths of 0.1, 0.2, 0.5, 1, and 20 μm for electric fields between 1 and 50 kV/cm at 300 K. The results are compared with earlier calculations and the significant features of the computed results are discussed. It is found that the electron motion for all channel lengths and for all fields is significantly affected by collisions. The threshold field for negative differential mobility increases, and the magnitude of the differential mobility decreases with decrease in the length of the sample. The maximum steady-state velocity increases with decrease in the length and may be as high as 5.4×107 cm/s for 0.1 μm samples.
TL;DR: In this paper, a light right-handed vector boson is found to require a strong departure from manifest left-right symmetry, and the effect on charmed particle decays and other nonleptonic processes are discussed.
TL;DR: In this paper, a unified study of the alkali metals with the Heine-Abarenkov model pseudopotential in conjunction with Taylor's dielectric function, and taking proper care of the consistency condition, yields satisfactory results for both the static and dynamic properties of these metals.
Abstract: From a careful analysis of the energy expression of the second-order pseudopotential theory, the reason for the breakdown of the consistency condition is pointed out. The problem is resolved by introducing the concept of local volume strain which introduces some modifications in the dynamical matrix and leads to the equality of static and dynamic elastic constants. A unified study of the alkali metals with the Heine-Abarenkov model pseudopotential in conjunction with Taylor's dielectric function, and taking proper care of the consistency condition, yields satisfactory results for both the static and dynamic properties of these metals. One interesting feature of the present investigation is that the theory satisfying the consistency condition reproduces the crossing of the longitudinal and transverse branches in the (100) direction for Li, while reproducing the normal behaviour for the dispersion curve of other metals.
Aus einer sorgfaltigen Analyse des Energieausdruckes der Pseudopotentialtheorie zweiter Ordnung wird der Grund fur das Versagen der Konsistenzbedingungen dargelegt. Das Problem wird durch Einuhrung des Konzepts der lokalen Volumenverzerrung gelost, das einige Modifikationen in die dynamische Matrix einbringt und zur Gleichheit der statischen und dynamischen elastischen Konstanten fuhrt. Eine zusammenfassende Untersuchung der Alkalimetalle mit dem Heine-Abarenkov-Modell-Pseudopotential in Verbindung mit der Dielektrizitatsfunktion vom Taylor unter sorgfaltiger Beachtung der Konsistenzbedingung liefert befriedigende Ergebnisse sowohl fur die statischen als auch dynamischen Eigenschaften dieser Metalle. Ein interessantes Merkmal der Untersuchung ist, das die die Konsistenzbedingung befriedigende Theorie das Uberschneiden des longitudinalen und transversalen Zweiges in der (100)-Richtung fur Li wiedergibt, wahrend es das normale Verhalten fur die Dispersionskurve der anderen Metalle reproduziert.
TL;DR: In this article, a model of a mechanism of degradation in thin-film Cu 2 S/CdS solar cells, arising out of the growth of a recombination layer in the skin region near the junction due to the two-way diffusion of copper and cadmium atoms, was proposed by Deb and Saha to explain the time variation in the performance of such cells using ceramic tablets.
TL;DR: In this paper, the authors investigated the nonlinear evolution of the amplitude evolution of a magnetized plasma with a CO/sub 2/ pulsed laser and showed that the non-linear increment of FR is opposite in sign to the value found more generally in the linearized approximation of the field equations.
Abstract: Faraday rotation (FR) has a nonlinear part which can be excited by a strong elliptically polarized electromagnetic wave in a plasma, even in the absence of a static magnetic field. It is due to the different dispersion rates of the strong left- and right-circular polarization components of the wave (the corresponding refractive indices are denoted by n/sub L/ and n/sub R/) and induces weak nonuniformities in a magnetized plasma. As a result the study of the nonlinear characteristics requires the WKB type of nonlinearly correct first-harmonic field solutions. This nonlinear evolution problem has been investigated in this paper. The new results, depending on both the field intensity and the nonlinearly induced spatial inhomogeneity, are (1) the nonlinearly correct expressions for n/sub L/ and n/sub R/, (2) the amplitude evolution equations in which the coefficients are slowly varying with respect to x (the Cartesian coordinate parallel to the direction of propagation) and their WKB solution, (3) the expression for the nonlinearly correct FR angle, and (4) a numerical estimation on the interaction of a plasma with a CO/sub 2/ pulsed laser in which it has been shown that the nonlinear increment of FR is opposite in sign to the value foundmore » in the linearized approximation of the field equations. The new results have been discussed in some special cases and some comments are given on enlarging the scope of further work on the FR of strong waves.« less
TL;DR: The electrical conductivity of bilayer lipid membranes of oxidized cholesterol has been measured separately in bathing solutions of sodium sulphate, sodium chloride, sodium bromide, sodium iodide and also in bathing solution of iodine and iodine containing these salts.
TL;DR: In this paper, the applicability of Gibbs equation has been tested experimentally from direct adsorption and interfacial tension measurement at nonpolar heptane/water and polar peanut oil/water interfaces.
TL;DR: In this article, a new speed measurement method using a microcomputer is presented, in which a definite small fraction of time for one revolution is counted using a software technique, and a definite bit size of the count is maintained by continuing counting over an optimum multiple of the initially measured time interval in case the bit-size of the initial count is less than a preset value.
Abstract: A new speed measurement method using a microcomputer is presented. In the initial part of the measurement, a definite small fraction of time for one revolution is counted using a software technique. A definite bit-size of the count is maintained by continuing counting over an optimum multiple of the initially measured time interval in case the bit-size of the initial count is less than a preset value. The multiple of the initial time period is measured with the help of an external counter, without any break in the continuity of counting. The speed is computed from the time count and displayed. For this measurement, only a standard digital speed transducer, a counter, and a microcomputer kit are required. The method has a small data acquisition and processing time, and gives a high accuracy that is programmable over a wide range of speed. The method is also quite economical.
TL;DR: In this article, the first-order reaction of hydrazinium ion to gold(III) was studied spectrophotometrically in a hydrochloric acid medium.
Abstract: Kinetics of the oxidation of hydrazinium ion by gold(III) have been studied spectrophotometrically in hydrochloric acid medium. The reaction is first-order with respect to both gold(III) and hydrazinium ion. Hydrogen ion inhibits the oxidation. The mechanism of the reaction is discussed.
TL;DR: Cyanonitrosyl complexes and their derivatives of the types [Cr(NO)(CN)4]2−, [Cr[ NO)(CN]3H2O]− and [Cr((CN)2 LL] [LL = 2,2′ bipyridine (bipy) or 1, 10-Phenanthroline (phen)] are synthesised directly from CrO42− using NH2OH as discussed by the authors.