Showing papers by "Government College published in 1983"

A melt mechanism for the thermal decomposition of ammonium dichromate

Abstract: Microscopic examination of (NH4)2Cr2O7 crystallites, previously decomposed to measured extents, has given strong evidence that reaction proceeds through the intervention of a melt. This reaction has previously been accepted as occurring in the solid phase and the use of higher magnifications than were applied previously revealed the progressive development of foam-like zones of active reaction. These structures are termed ‘fusion nuclei’. We conclude that an initial, and probably reversible, dissociation of the reactant (NH4)2Cr2O7⇌ 2NH3+ H2O + 2CrO3 is followed by a sequence of steps by which NH3 and/or NH+4 is oxidized in the CrO3 melt to N2 and N2O, possibly involving the intervention of NH4NO2 and NH4NO3 respectively. Since these various consecutive and concurrent reactions contribute to the overall chemical change we conclude that the quantitative characterization of their kinetics and stoichiometry requires the separate investigation of selected simpler reaction mixtures. Some observations on the reaction of ammonia with molten CrO3 are discussed.

A Design for Testability of Undetectable Crosspoint Faults in Programmable Logic Arrays

Abstract: In this paper, the validity of single fault assumption in deriving diagnostic test sets is examined with respect to crosspoint faults in programmable logic arrays (PLA's). The control input procedure developed here can be used to convert PLA's having undetectable crosspoint faults to crosspoint-irredundant PLA's for testing purposes. All crosspoints will be testable in crosspoint-irredundant PLA's. The control inputs are used as extra variables during testing. They are maintained at logic 1 during normal operation. A useful heuristic for obtaining a near-minimal number of control inputs is suggested. Expressions for calculating bounds on the number of control inputs have also been obtained.

Cooperative phenomena in ternary superconductors

Abstract: A microscopic theory of ferromagnetic superconductors is developed from first principles. Self-consistent equations for the superconducting order parameter Δ and spontaneous magnetizations 〈S z 〉 are derived using a Green's function technique and considering thef-d exchange effect up to the second order. The theory is applied to explain the experimental results in the reentrant superconducting ternary system ErRh4B4. The present model explains reentrant behavior, predicts the coexistence of superconductivity and ferromagnetism in a very small range of temperature, the suppression of superconductivity by ferromagnetism, and vice versa. These results are in excellent agreement with the experimental data and predictions of other models. The behavior of the spontaneous magnetization, the superconducting order parameter, the specific heat, and the density of states is also studied.

Surface Tension Behavior and Micellization of Cadmium(ll) Soap-Benzene and Methanol at 40°C

Abstract: The surface tension of cadmium caprate and laurate in benzene-methanol mixtures of varying composition has been measured at 40 ± 01°C The critical micelle concentration (CMC) values depend upon the composition of the solvent mixture and are found to decrease with increasing chain length of cadmium soaps Previous findings about the CMC of the soaps are in general confirmed The data have been discussed on the basis of Szyskowski's empirical equation, The parameters X, Y, and (-X In Y) are found to decrease up to ∼50% methanol concentration Above that, the trend vanishes This confirms that the nature of the micelles formed below and above 50% methanol concentration is quite different The area covered by 1 g-mole of the soap also shows that the change in the nature of micellization takes place at ∼50% methanol concentration

Iqbal's Concept of God: An appraisal

Abstract: I do not agree with Professor M. M. Sharif in his book About Iqbal and His Thought that Allama Iqbal's concept of God passed through three stages, and that at one stage he identified him with ‘Beauty’. This may be said on the basis of his few earlier poems (included in Baang-i-Darā), but they never purported to give any idea about God; they were at best ghazals on nature and offered only stray reflections. Iqbal properly developed his concept of God in his lecture entitled ‘The Conception of God and The Meaning of Prayer’ (included in The Reconstruction of Religious Thought in Islam). I may mention at the outset that I am going to base my appraisal on the said lecture of Iqbal.

Spectroscopic studies of undoped and doped polystyrene films

Abstract: Spectroscopic (i.r., u.v.) studies of undoped polystyrene and that doped with Acrylic Acid films (30μ thick), prepared by isothermal immersion technique, have been reported. It is found that in the case of i.r. spectra an additional absorption peak appears near 1420cm−1, whereas those present near 1300 and 980cm−1, as shoulders in the undoped sample, appear as sharp peaks in the doped samples. In the region 3300–2500cm−1 a broadening appears in the doped films which increases with the dopant concentration. In the case of u.v. spectra, out of four absorption regions present in the undoped films two bands merge and only three appear in the doped ones. The u.v. absoption increases with the dopant concentration. These results have been explained on the basis of a charge transfer complex formation due to the interaction between the dopant and the polymer matrix.

Excitation of magnetoacoustic waves by two microwave beams in InSb

Abstract: An investigation is made of the resonant excitation of magnetoacoustic wave at the difference frequency of two microwave beams propagating in a magnetoactive solid state plasma viz. n-InSb. Due to the interaction of the two waves in the semiconductor the ponderomotive force at the difference frequency becomes finite and generates a magnetoacoustic wave if the dispersion relation corresponding to magnetoacoustic wave is satisfied. The analysis shows that there is a finite probability of excitation of an acoustic wave alongwith the magnetoacoustic wave. The excited acoustic and magnetoacoustic waves couple at magnetic fields when the thermal pressure is equivalent to the magnetic pressure. The propagation characteristics of the coupled wave are also studied. The results show that microwave beams of power densities 1 MW cm−2 excite magnetoacoustic wave of power density 0.04 kW cm−2 when ωc/ω = 0.1. The increase in magnetic field increases the power density of the excited magnetoacoustic wave whereas it tends to reduce the refractive index and attenuation constant of the coupled wave. Die Resonanzanregung einer magnetoakustischen Welle mit der Differenzfrequenz zweier Mikrowellen, die sich in einem magnetoaktiven Festkorperplasma z. B. n-InSb ausbreiten, wird untersucht. Infolge der Wechselwirkung der beiden Wellen im Halbleiter wird die ponderomotorische Kraft bei der Differenzfrequenz endlich und erzeugt eine magnetoakustische Welle, wenn die der magnetoakustischen Welle entsprechende Dispersionsbeziehung erfullt ist. Die Analyse zeigt, das eine endliche Anregungswahrscheinlichkeit einer akustischen Welle zusammen mit der magnetoakutischen Welle existiert. Die angeregte akustische und die magnetoakustische Welle koppeln bei Magnetfeldern wo der thermische Druck gleich dem magnetischen Druck ist. Die Ausbreitungscharakteristiken der gekoppelten Welle werden ebenfalls untersucht. Die Ergebnisse zeigen, das Mikrowellenstrahlen mit Leistungsdichten von 1 MW cm−2 magnetoakustische Wellen mit einer Leistungsdichte von 0,04 kW cm−2 anregen, wenn ωc/ω = 0,1 ist. Ein Anwachsen des Magnetfeldes erhoht die Leistungsdichte der angeregten magnetoakustischen Welle, wobei der Brechungsindex und die Dampfungskonstante der gekoppelten Welle zur Reduzierung tendieren.

Dusty effects on pulsating viscous flow of two immiscible fluids between two parallel plates

Abstract: The flow of two immiscible incompressible dusty viscous fluids between two parallel plates generated by a pulsating pressure gradient is investigated. Velocity fields for the fluid-particle system along with the expressions for the skin friction drag at the plates are obtained and studied graphically. It is found that there is an immediate response to pressure fluctuations in the first stream at low frequency range 0<σ≤4 being maximum at σ=4. On the contrary, the second stream is more responsive to fluctuations at relatively higher frequencies. The maximum response in this case is shifted to σ=16.

Effect of annealing and oxygenation on the DC conductivity of amorphous germanium

Abstract: Thin films of amorphous germanium were deposited in an oxygen atmosphere.dc conductivity results are interpreted considering the possibility of the formation of Ge-O bonds. The density of states was determined. Results of conductivity are interpreted using the Davis-Mott model. Change in conductivity in annealed films of V-a-Ge and O-a-Ge is also reported.