SUBSTITUTIONAL EFFECT OF Zn AND Pr IN YBa2Cu3O7-delta

The co-doping effect of Zn and Pr impurities in the compound of composition Y1-xPrxBa2[Cu1-yZny](3)O7-delta with x = 0.1, x = 0.2 and 0 <= y <= 0.1 has been investigated by analyzing the results of electrical resistivity measurements. It is found that for Pr substitution at x = 0.1, there is a minimal influence on in-plane processes, thereby slightly affecting T-c and residual resistivity rho(0), but with the resistivity slope d rho/dT becoming large for the range of y from 0.03 to 0.06, leading to a larger depinning effect. For x = 0.2 a drastic change is observed whereby rho(0) becomes abnormally large, and d rho/dT becomes negative, implying totally pinned charge stripes and no depinning. The second observation therefore suggests that Pr substitution converts the overdoped system to an optimally doped system, leading to the universal superconductor-insulator transition.

Sequence of reactions leading to cytochrome-p-450 synthesis-effect of drugs

The effect of phenobarbital on the rates of the synthesis of the protein and heme moieties of cytochrome P-450 has been studied. For this purpose, cytochrome P-450 has been partially purified as its P-420 derivative and the labeled amino acid incorporation into the protein has been studied after subjecting a partially purified preparation to sodium dodecyl sulfate gel electrophoresis. The incorporation studies into the protein species after sodium dodecyl sulfate gel electrophoresis reveal that the drug primarily accelerates the rate of apoprotein synthesis followed by an increase in the rate of heme synthesis. The messenger for apocytochrome P-450 appears to be fairly stable.

Effect of 2-allyl-2-isopropylacetamide on poly(adenylic acid)-containing ribonucleic acid.

A single administration of 2-allyl-2-isopropylacetamide, a porphyrinogenic drug, enhanced the 32P-labelling of nucleoplasmic as well as cytoplasmic poly(A)-containing RNA in rat liver. The synthesis of total microsomal RNA is only marginally increased under these conditions. The drug enhances the labelling of a variety of cytoplasmic poly(A)-containing RNA species, and this effect is counteracted by the simultaneous administration of haemin. 2-Allyl-2-isopropylacetamide also enhanced the release of RNA from the nucleus to the cytoplasm.

Effect Of Human Chorionic Gonadotrophin And Ovine Luteinizing Hormone On Rat Ovarian Macromolecular Metabolism

Administration of human chorionic gonadotrophin (HCG) or ovine LH to immature rats primed with pregnant mare serum gonadotrophin (PMSG) stimulated the rate of synthesis of polyadenylic acid (poly A)-rich RNA in the ovaries. The rate of total RNA synthesis was not affected significantly by hormone treatment, whereas protein synthesis was enhanced. The increase in the rate of synthesis of poly(A)-rich RNA in the ovaries could be inferred as induction of messenger RNA synthesis after the hormone treatment. The poly(A)-rich nature of the isolated RNA was established by oligo(dT)–cellulose chromatography, binding to Millipore filter disks and hydridization with [3H]polyuridylic acid. The level of cyclic AMP in the ovaries of such rats was also raised after administration of LH, the increase coincided with the increase in the rate of synthesis of poly(A)-rich RNA. The implications of these results are discussed in the light of the biochemical basis of luteinization and the action of LH.

Effect of depletion of vitamin A, followed by supplementation with retinyl acetate or retinoic acid, on regeneration of rat liver

After partial hepatectomy the net increase in tissue weight and in RNA, DNA and proteins in the regenerating liver was markedly less in vitamin A-deleted or retinoic acid-supplemented male rats, compared with the corresponding normal control or retinyl acetate-supplemented ones.

A Nonmoving-Part Fluidic Display Using Photoelastic Effect

Digital fluidic and pneumatic systems incorporate displays for the presentation of information to the operator. Displays reported so far for such systems use moving pistons, tapes, and other mechanisms leading to lower reliability. This paper describes a nonmoving part fluidic display employing the photoelastic effect. The display is pressure actuated and has a long life. When fabricated from compatible materials, this device can withstand hostile environments like nuclear radiation, vibrations, etc. The display is compact, economical and is virtually maintenance free. The display unit has been tested in the laboratory for reliability and speed of response.

Effect of creep deformations in mechanical systems under combined deterministic and random inputs

The effect of creep on the vibrations of a single degree of freedom system subjected to combined random and deterministic excitation has been studied in this paper. The deterministic part of the excitation is assumed to be a sinusoidal function while the random part of the excitation is considered as a narrow band process with a central frequency equal to the frequency of sinusoidal part of the excitation. Creep, an energy absorbing process, introduces an equivalent damping into the system. A measure of this damping and the statistical properties of the response of the mechanical system have been derived.

Zeeman effect of NQR in 4,6-dichloropyrimidine and 6-chloro 2,4-dimethoxypyrimidine

Zeeman (35Cl) NQR studies in polycrystalline samples of 4,6-dichloropyrimidine and 6 chloro 2,4 dimethoxypyrimidine show that the asymmetry at the four chemically inequivalent chlorine sites in the former is about 10%, while in the latter (one line) the asymmetry is almost zero. Using a valence-bond picture, C-Cl bonds in 4,6-dichloropyrimidine have been characterised, and the results are also compared with those in a corresponding benzene compound using a simple molecular orbital calculation. The axial symmetry of C-Cl bond in the second compound has been attributed to mesomeric effects.

Effect of membrane action on the plastic collapse load of circular orthotropic slabs with fixed edges

In the case of reinforced concrete slabs fixed at the boundaries, considerable enhancement in the load carrying capacity takes place due to compressive membrane action. In this paper a method is presented to analyse the effects of membrane action in fixed orthotropic circular slabs, carrying uniformly distributed loads. Depending on the radial moment capacity being greater or less than the circumferential moment capacity, two cases of orthotropy have been considered. Numerical results are worked out for certain assumed physical parameters and for different coefficients of orthotropy. Variations of load and bending moments with the central deflection are presented.

The effect of lecithin on the burning rate of AP-Al---polyester propellant

Abstract is not available.

Effect of manganese dioxide on the thermal decomposition of ammonium perchlorate

Thermal decomposition of powdered ammonium perchlorate, catalysed by manganese dioxide (MnO2), has been studied in the low concentration ranges of the catalyst. MnO2 sensitises the thermal decomposition of ammonium perchlorate. The activation energy estimations of catalysed ammonium perchlorate show that the value is about 30 kcal/mol throughout the low and the high temperature regions whereas uncatalysed ammonium perchlorate gives two activation energies, 20 kcal/mol in the low temperature region (280-320°C) and 60 kcal/mol in the higher temperature region (350-390°C). This behaviour has been explained on the basis of an electron transfer process. The effectiveness of MnO2 in the thermal decomposition further increases on pre-heating the sample at 50°C for two weeks; manganese ions enter the ammonium perchlorate lattice during the process of pre-heating.

Storage stability of solid rocket fuel. 1. Effect of temperature

Ageing behaviour of polystyrene (PS)/ammonium perchlorate (AP) propellent leading to ballistic changes has been studied. It follows a zero-order kinetic law. Ageing behaviour leading to change in burning rate ( ) in the temperature range of 60–200 ° C was found to remain the same. The dependence of the change of the average thermal decomposition (TD) rate at 230 and 260°C on the change in burning rate for the propellant aged at 100 ° C in air suggests that the slow TD of the propellant is the cause of ageing. The safe-life (for a pre-assigned burning-rate change limit) at 25 ° C in air has been calculated as a function of the rate of change.

Effect of pretreatment on the sublimation of ammonium perchlorate

The effects of pretreatments on the sublimation of pure ammonium perchlorate (AP) were studied by differential thermal analysis. The addition of inorganic salts (doping), or preheating, lead to desensitisation of the sublimation process, whereas it was sensitised by precompression. Sublimation increased with decrease in the particle size of the AP from 500 to 200 microns, but decreased with a further decrease in size from 200 to 100 microns. The results are interpreted in terms of gross imperfections and strain in the AP crystals.

The effect of suction on boundary layer for rotating flows with or without magnetic field

The effect of suction on the steady laminar incompressible boundarylayer flow for a stationary infinite disc with or without magnetic field, when the fluid at a large distance from the surface of the disc undergoes a solid body rotation, has been studied. The governing coupled nonlinear equations have been solved numerically using the shooting method with least square convergence criterion. It has been found that suction tends to reduce the velocity overshoot and damp the oscillation.

Effect of viscosity on internal waves from a source in a wall

The solution for a line source of oscillatory strength kept at the origin in a wall bounding a semi-infinite viscous imcompressible stratified fluid is presented in an integral form. The behaviour of the flow at far field and near field is studied by an asymptotic expansion procedure. The streamlines for different parameters are drawn and discussed. The real characteristic straight lines present in the inviscid problem are modified by the viscosity and the solutions obtained are valid even at the resonance frequency.