System for measuring airflow parameters near the ocean surface

An acoustical method is described for measuring the characteristics of air-flows at the boundary between the ocean and the atmosphere. Experimental results are given from measurements of the vertical component of the airflow velocity.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 59, No. 6, pp. 1005–1011, December, 1990.     

Influence of magnetization variation near the surface on spin wave modes

It is shown that some information on the character of the pinning (surface anisotropy and/or magnetization variation near the surface of the film) may be obtained from the angular dependence of the spin wave resonance spectra. The two contributions to the pinning may be of the same order of magnitude. The differences between the angular dependences of the spectra, when each of the two mechanisms is assumed to act separately yet to produce the same pinning in perpendicular resonance, can be large for asymmetrical large negative pinnings when rich spin wave spectra with surface modes are predicted.     

Influence of roughness parameters on coefficient of friction under lubricated conditions

Surface texture and thus roughness parameters influence coefficient of friction during sliding. In the present investigation, four kinds of surface textures with varying roughness were attained on the steel plate surfaces. The surface textures of the steel plates were characterized in terms of roughness parameter using optical profilometer. Then the pins made of various materials, such as Al-4Mg alloy, Al-8Mg alloy, Cu, Pb, Al, Mg, Zn and Sn were slid against the prepared steel plates using an inclined pin-on-plate sliding tester under lubricated conditions. It was observed that the surface roughness parameter, namely, R _a , for different textured surfaces was comparable to one another although they were prepared by different machining techniques. It was also observed that for a given kind of surface texture the coefficient of friction did not vary with R _a . However, the coefficient of friction changes considerably with surface textures for similar R _a values for all the materials investigated. Thus, attempts were made to study other surface roughness parameters of the steel plates and correlate them with coefficient of friction. It was observed that among the surface roughness parameters, the mean slope of the profile, Del a(Δ _a ), was found to explain the variations best.     

混凝土表面开口裂缝对近表面声波影响

基于混凝土近表面不同波型的声速,分析开口裂缝对声波的影响。有限元仿真结果表明,激励源辐射的初始纵波P经裂缝端点衍射产生纵波P-P与横波P-T,P-T以一定的角度射向混凝土表面经模式转换产生纵波P-T-P;初始横波T在裂缝端点衍射产生纵波T-P与横波T-P;初始瑞利波R在裂缝端点衍射后除了产生纵波R-P与横波R-S外继续沿着固体表面传播(R-R)。在此基础上,基于变型波到达接收阵元的时刻定量检测裂缝的深度,检测结果较单面平测法具有更高的信噪比与检测精度,可辅助单面平测法更精确地定量检测混凝土开口裂缝的深度。     

Influence of charge flow along a semiconductor surface on the nature of the multiplication coefficient in a silicon-wide-gap layer structure

It has been shown that the flow of mobile minority carriers along the semiconductor-wide-gap layer interface substantially influences the uniformity of the multiplication coefficient in an avalanche photodetector. Around inhomogeneities in the semiconductor substrate, a “dead zone” of fairly large area is formed, where the multiplication coefficient is several orders of magnitude lower than that on the remaining area of the device. Specific methods are proposed to improve the uniformity of the avalanche process in a semiconductor-wide-gap layer structure. Pis’ma Zh. Tekh. Fiz. 23, 72–76 (April 26, 1997)     

Cross section for the interaction of slow neutrons with CO2 near the vaporization critical point

The results of studies of the temperature dependence of the total cross section for the interaction of slow neutrons with CO₂ in a wide temperature range, including the vaporization critical point, are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 50, No. 5, pp. 760–763, May, 1986.     

Effect of metakaolin on the near surface characteristics of concrete

Results on an investigation dealing with the effect of metakaolin (MK) on the near surface characteristics of concrete are presented in this paper. A control concrete having cement content 450 kg/m³ and w/c of 0.45 was designed. Cement was replaced with three percentages (5, 10, and 15%) of metakaolin weight. Tests were conducted for initial surface absorption, sorptivity, water absorption and compressive strength at the ages of 35, 56, and 84 days. Test results indicated that with the increase in MK content from 5 to 15%, there was a decrease in the initial surface absorption, decrease in the sorptivity till 10% metakaolin replacement. But at 15% MK replacement an increase in sorptivity was observed. All mixtures showed low water absorption characteristic i.e. less than 10%. Compressive strength shared an inverse relation with sorptivity. Higher MK replacements of 15% are not helpful in improving inner core durability, even though it helps in improving surface durability characteristics.     

Influence of surface conductivity on sensitivity of acoustic wave gas sensors based on multilayered structures

The influences of the surface conductivity on the velocity of an acoustic wave (AW) in a multilayered material are studied theoretically with the transfer matrix method and the conductivity sensitivity of the AW sensor is presented. It is found that the velocity of the AW increases with decreasing surface conductivity and vice versa. The result is used to explain the abnormal response of AW sensors, in which the central frequencies of AW sensors increase after they sorb the detected gases. Meanwhile, the conductivity sensitivity is found to be related to the dielectric constants of the multilayered material and the electromechanical coupling coefficient of the sensor. Finally, the sensitivities of AW sensors based on multilayered structures are optimized by considering the influences of the surface conductivities of the sensors with different initial conductivities and thicknesses of the sensitive layers.     

Effects of process parameters on surface morphology of metal powders produced by free fall gas atomization

There are a number of process parameters which affect the characteristics of metal powders produced by free fall gas atomization. In the following work effects of various process parameters like apex angle of atomizer, focal length of atomizer, number of nozzles, diameter of nozzles, diameter of liquid metal delivery tube, superheat of liquid metal and type of metal etc. were studied on their surface morphology. It was observed that shape of powder particles depends on apex angle, superheat of liquid metal, type of metal and particle size range within a powder collective. Other parameters like focal length of atomizer, number of nozzles, diameter of nozzles and diameter of liquid metal delivery tube were found to have no effect on the shape of powder particles. However, Surface porosity and solidification shrinkage were observed on almost all types of metal powders.     

Influence of friction stir processing parameters on surface modified 90Cu-10Ni composites

Friction Stir Processing (FSP) has emerged as a distinctive and pioneering solid state technique to produce surface composites. The objective of the present research is to produce reinforced 90/10 Copper–Nickel surface composites with different carbide-based ceramic particles through FSP and study the relationship of its dynamic parameters including tool rotational speed, tool traverse speed, and width of the groove over the surface behavior. Responses such as sliding wear, microhardness, and surface modified area in the friction stir processed region are modeled using polynomial, nonlinear, multiple regression based on the central composite design of experiment. Analysis of the developed models showed that the FSP parameters; traverse speed, rotational speed, and groove width have significant influence on both the sliding wear and microhardness of developed surface composite. And furthermore, tool rotational speed and tool traverse speed, simultaneously control dispersion of reinforcement in the surface. To validate the abovementioned noteworthy results and to study the microstructural aspects, selected specimens were carried over metallurgical analysis and the obtained results were put forward in detail in this paper.     

Dispersion relation of surface plasmons near photonic band gaps: Influence of the interaction with light

Abstract

We present an experimental and theoretical study of the photonic band gap in the propagation of surface plasmons (SPs) on periodically corrugated surfaces. Our main purpose is to investigate the case where the band gap width is larger than the energy distance between the SP dispersion curve for a flat surface and the light line. We introduce a physical model of the interaction of light waves with SPs and derive an analytical expression for the SP wave vector near band gaps based on the coupled-mode approach involving three interacting modes (two of them are SP modes and one is a light mode). By using the interferometric measurement we have studied, for the first time, the SP propagation parameters in the vicinity of the photonic band gap (10 μm wavelength region). The predictions of our theory are in good agreement with the experimental data.     

Influence of the blowoff of boundary gas from the discharge chamber of a plasmatron on the parameters of the jet

The results of an experimental investigation of the parameters of an argon jet heated in a plasmatron with an anode permitting the removal of part of the cool gas from the discharge chamber are presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol.52, No. 1, pp. 141–148, January, 1987.     

Thermal expansion coefficient of 3He near 1 mK

A measurement of the thermal expansion coefficient of ³He at 0 bar from 0.6 to 3 mK is presented. At the superfluid transition the expansion coefficient changes by 1.1 × 10^\s-6 mK^\s-1. This change is consistent with predictions based on thermodynamic arguments and existing heat capacity data.This work was supported by NSF grant DMR 79-25098.     

Determination of vaporization enthalpies of polychlorinated biphenyls by correlation gas chromatography

The vaporization enthalpies of 16 polychlorinated biphenyls have been determined by correlation gas chromatography. This study was prompted by the realization that the vaporization enthalpy of the standard compounds used in previous studies, octadecane and eicosane, were values measured at 340 and 362 K, respectively, rather than at 298 K. Adjustment to 298 K amounts to a 7-8 kJ/mol increment in the values. With the inclusion of this adjustment, vaporization enthalpies evaluated by correlation gas chromatography are in good agreement with the values determined previously in the literature. The present results are based on the vaporization enthalpies of several standards whose values are well established in the literature. The standards include a variety of n-alkanes and various chlorinated hydrocarbons. The vaporization enthalpies of PCBs increased with the number of chlorine atoms and were found to be larger for meta- and para-substituted polychlorinated biphenyls.     

Influence of the nitridation parameters on the stoichiometry, structure and specific surface area of zirconium phosphate oxynitride catalysts

Oxygen can be exchanged by nitrogen atom in high surface specific and amorphous zirconium phosphate solids thank to nitridation process. Various nitridation parameters influence the O/N substitution. A minimum temperature of 550°C is required for efficient nitridation whereas temperature higher than 850 and 1300°C induces reduction of phosphorus and zirconium atoms respectively. In intermediate temperature range, O/N exchange increases with temperature as well as with time of nitridation. In these conditions, the ZrPON solids obtained are X-ray amorphous and a slight decrease of precursor specific surface area is observed (110–210 m² g^-1).     

Dependence of the thermal coefficient of accommodation and the emissivity on surface roughness

Results are presented of a theoretical and experimental investigation of the dependence of the thermal coefficient of accommodation and emissivity on parameters characterizing surface roughness.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 20, No. 1, pp. 114–118, January, 1971.     

Monitoring the coefficient of variation using a variable parameters chart

This article is the first of its kind which proposes a Variable Parameters (VP) chart to monitor the coefficient of variation (CV). Formulae for various performance measures and the algorithms to optimize these performance measures are proposed. The VP CV chart consistently outperforms the five alternative CV charts in the literature, for all shift sizes. Compared to the Exponentially Weighted Moving Average (EWMA) CV² chart, the VP CV chart outperforms it for moderate and large shift sizes, while for small shift sizes, the EWMA CV² chart outperforms the VP CV chart. Subsequently, the VP CV chart is implemented on an industrial example.