Analysis of three-phase AC-DC converters under unbalanced supplyconditions

A three-phase AC-DC converter is analyzed, and the performance of the converter under balanced conditions is evaluated. It has been observed that the level of unbalance plays a significant part in the converter characteristics, especially at the lower output voltage range     

Amorphous binary alloys obtained by electrolytical and chemical methods

Amorphous alloys, generally obtained by splat cooling condensation on a cold support or sputtering, were prepared in our laboratory at ambient temperature by two other methods. The first one, the oxidoreduction in liquid phase, gives films, the thickness of which is 500 to 2000 A, deposited on an isolating support — glas, plastic or ceramic. The second one, electrolysis of adapted solutions, allows us to obtain some thick layers the thickness of which is in this case, 1 to 100 microns. The support is a conductor, for example, a copper leaf.Experiments reveal a local order characterized by the absence of diffraction peaks in the experimental interference function which is chiefly formed by diffuse rings. We can obtain amorphous materials at ambient temperature if the bath composition leads to an alloy which contains at least 15% of atoms of the metalloid in the case of phosphorous, and 20% of atoms with boron. The upper limits are, respectively, 25 and 35%. It does not seem possible to obtain a bigger quantity of metalloid with these two methods.The local order can be represented by an assembly of clusters in which chemical bonds exist between the metal and metalloid atoms. Every cluster is surrounded by a domain where atomic position is distributed following a Gaussian function. Beyond that the material is completely amorphous.     

A Statistical Signal Prediction Model for Communication Receivers

Many communication receivers receive the desired signal in presence of interference signal. A statistical antenna and propagation model is described which predicts the expected values of the desired and undesired signal levels ? and ?, respectively, the standard deviations of the desired and undesired signals ?s and ?I, respectively, and their correlation coefficients PSI. The expected values of the signal levels are expressed in terms of the random parameters of the radio frequency power fed into the transmitting antenna, its efficiency, gain, propagation path loss, receiving antenna gain, receiving antenna loss, and input impedance of the receiver.     

Relativistic Dirac-Fock-Slater orbital binding energies and one-electron transition energies Cu XVI–XIX,Zn XVII–Zn XX,Ag XI–Ag XIX,and Sn XVIII–Sn XXIII

Listed here are the electron orbital energies of the ions Cu XVI to Cu XIX, Zn XVII to Zn XX, Ag XI to Ag XIX, and Sn XVIII to Sn XXIII for different configurations defined by the outermost electron. These values have been computed by the relativistic self-consistent field method. From these configurations the one-electron transition energies in sudden approximation are obtained. Adiabatic transition energies can also be obtained but are not listed here. These tables may be helpful in the identification of transitions in the spectra which are currently being measured in laser-produced plasmas.     

A comparison of conductive and crystallographic effects of the phase transition in electrochemical nickel-boron layers

Experimental data related to the variations with temperature in the film resistivity of amorphous nickel-boron layers (electrochemically deposited) and its temperature coefficient are used for identifying the temperature for the phase transition. Suggestions are presented for interpreting the observed shifts in the resistivity and in the product of resistivity and its temperature coefficient.     

Robust analysis of two-way models with repeated measures on both factors

Summary A robust analysis of two-way models with repeated measures on both factors is developed using a dispersion function. This robust analysis gives users a complete inference: Estimation, tests for the general linear hypotheses, and multiple comparison procedures. Asymptotic relative efficiencies of the rank tests with respect to the least-squares counterpart are discussed. Analyses of two real life examples from medical and pharmaceutical studies are presented.     

Photoelectrochemical and impedance spectral studies on electrodeposited (CdGa)Se films

Polycrystalline thin films of (CdGa)Se of variable composition were synthesised by the electrochemical codeposition process. Characterization of these electrodeposits has been carried out on the basis of photoresponsiveness and photoaction spectral studies. Impedance measurements were carried out to have an estimate of the effect of progressive inclusion of Ga on the corrosion behaviour of the electrodeposits. X-ray diffraction and scanning electron microscopic studies have also been carried out.     

UKI-03 device for checking the generator water-cooled stator winding insulation

Conclusion A diagnostic microprocessor device for checking the generator water-cooled stator winding insulation, realizing semiautomatic measuring of the level of resistance and absorption coefficient of the stator winding insulation, in which case the shunting effect of the water hoses is eliminated, was developed and is operating successfully. Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 3, pp. 31–33, March, 1996.     

Strain-aging of vanadium,niobium or titanium-strengthened high-strength low-alloy steels

Four commercially available high-strength low-alloy (HSLA) steels were evaluated in this study. It was determined that all four steels were susceptible to strain-aging by interstitial solutes. The increase in strength due to strain-aging was similar to that observed in a low carbon steel studied for comparison. At high levels of prestrain, the percent loss in ductility in the HSLA steels was comparable to that observed in the low-carbon steel in specimens prestrained to the same fraction of the total elongation of the as-received metal. However, when considered on an absolute basis, the residual ductility in the HSLA steels was 25 to 50 pct of that observed in the low-carbon steel. The kinetics of strain-aging were briefly examined. Indications are that the kinetics are slower in the HSLA steels than they are in the low-carbon steel.