Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Assessment of intakes of mixtures of radionuclides

Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides.     

一起空分设备主换热器过冷故障的分析

在KDON-6000/3500型空分设备调试过程中,由于经验不足、操作不当,造成主换热器发生过冷故障。停运一台膨胀机,采用液氧返充操作使空分设备恢复正常工况。介绍故障发生经过和原因分析过程,以及防止同类故障再次发生的预防措施。     

方波幅度的测量不确定度

介绍了用众数法评价方波幅度时的不确定度分析和评价过程;讨论了主要的不确定度来源,包括众数判别区间的影响、波形测量系统幅度测量误差的影响等等;给出了减小不确定度的主要措施,并结合一个实例,给出了方波幅度的不确定度评价结果。     

On the mechanism of action of inhibitors of hydrogenation in the process of electrodeposition of metals

We develop a new approach to the investigation of the effect of inhibitors of hydrogenation of the base in the process of electrodeposition of metals. We established the relationship between the structure of molecules of the inhibitor, their ability to interact with atomic hydrogen, their adsorption properties, the contents of various forms of hydrogen in steel, and physicomechanical parameters of the latter. On the basis of the results of quantum-chemical computations of electron parameters of molecules, we demonstrate the possibility of prediction of the efficiency of inhibitors of hydrogenation and regularities of changes in the strength and plastic properties of steel. Dnepropetrovsk State University, Dnepropetrovsk. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 32, No. 6, pp. 7–17, November–December, 1996.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

The variation of the parameters of front processes of thermal decomposition of condensed systems in the vicinity of the limit of thermodynamic stability

Analysis is made of the variation of the basic parameters of front processes of thermal decomposition of condensed systems, namely, the velocity of front motion, the surface temperature, and the thickness of zones of chemical reactions and heating, as the intensity of thermal impact increases and the temperatures in the front approach the limit of thermodynamic stability.     

Study of Flowability of Powders. Effect of the Addition of Lubricants

In early paper we have studied the flow parameters of powders using a ring shear. Also, we have evaluated an adequate method to estimating flowability according to powder characteristics. The goal of this article is the study of the action of three lubricants, magnesium stearate, PRUV® and PRECIROL®, on the flowability of an excipient for direct compression, Maltrin® M510. Flow characteristics are evaluated with flowrate, repose angle and compressibility. The influence of concentration and mixing time is also evaluated. Compressibility did not discriminate the lubricant effect. The maximum correlation coefficient flowrate and the repose angle showed the best flowability for magnesium stearate mixtures.     

Effect of heterogeneity of materials and heat cycles on diffusion of hydrogen as a factor of the risk of development of hydrogen degradation of metals

Conclusions The analysis results show that in the presence of hydrogen the nonstationary nature of the thermal effects (heat changes, thermal cycles) in the presence of heterogeneities may on its own be a factor causing a high risk of hydrogen degradation and may be of the implicit type (hidden). The degree of risk depends, in particular, on the kinetics of thermal processes. These defects must be taken into account by estimating the properties of materials after the effect of hydrogen and solving the problems of ensuring safety of structures both in the design stage and controlling efficiency and in determining the optimum (permissible) operating conditions, and also in determining the residual service life. In certain cases the conditions of transition of thermal processes may be of controlling importance for the efficiency of materials in structures.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, No. 6, pp. 7–20, November–December, 1992.     

Limit of error of measurements of a mass of oil and oil products

Recommendations for establishing measurement error limits are obtained on the basis of analysis of errors and diagnosis of indirect measurements of a mass of oil and oil products. Translated from Izmeritel'naya Tekhnika, No. 5, pp. 19–21, May, 1998.     

Assurance of the Uniformity of Measurements of the Power of Laser Radiation

On the basis of an analysis of the principle underlying the construction of standards and systems designed for reproduction of the unit of mean power and energy of laser radiation, it is shown that these standards consist of unified subsystems that carry the principal metrological load. By means of such a division, it is possible to realize a systems-engineering synthesis of standards with preassigned error. __________ Translated from Izmeritel'naya Tekhnika, No. 11, pp. 20–23, November, 2005.     

Justification of rheotechnological methods of control of colmatage

Theoretical and experimental investigations of localized structures appearing in filtration of nonlinear viscoplastic drilling fluids are reported. The depth of penetration of mud into a porous medium is shown to be dependent on the rate of change of the pressure on the boundary. This fact has been suggested for use in creation of colmatage barriers that prevent penetration of drilling mud into strata.Central Asia State Scientific-Research and Design Institute of the Gas Industry, Tashkent, Uzbekistan. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 5, pp. 573–579, May, 1994.     

Study of Flowability of Powders. Effect of the Addition of Lubricants

Abstract

In early paper we have studied the flow parameters of powders using a ring shear. Also, we have evaluated an adequate method to estimating flowability according to powder characteristics. The goal of this article is the study of the action of three lubricants, magnesium stearate, PRUV® and PRECIROL®, on the flowability of an excipient for direct compression, Maltrin® M510. Flow characteristics are evaluated with flowrate, repose angle and compressibility. The influence of concentration and mixing time is also evaluated. Compressibility did not discriminate the lubricant effect. The maximum correlation coefficient flowrate and the repose angle showed the best flowability for magnesium stearate mixtures.     

空调冷源的环境性能比较

根据国际标准化组织的生命周期评价标准,建立了空调冷源的能量生命周期清单模型,提出了环境影响评价方法.对常见的空调冷源(离心机组、螺杆机组、风冷热泵、天然气直燃机、柴油直燃机、蒸汽双效嗅化锂机组)进行了生命周期清单分析和环境影响评价,并利用权重三角形解释了权重对综合评价结果的影响.综合评价结果表明:电力结构对离心机组的环境性能影响较大,但对天然气直燃机影响较小.因此天然气直燃机和离心机组的环境性能比较应考虑电力结构的影响,在我国1999年的电力结构下,天然气直燃机的环境性能优于离心机组,在我国2010年的电力结构下,两者的环境性能相当,在美国1999年的电力结构下,天然气直燃机的环境性能比离心机组差.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

一起珠光砂堵塞过冷器的故障处理

在KDON-4500/4500-3型空分设备精馏塔大加温过程中发生管道断裂故障,珠光砂进入纯氮通道堵塞过冷器并造成空分设备停车。介绍为排除故障而对过冷器进行正、反向吹扫的管线流程。阐述了为避免同类故障再次发生,对冷箱内管道、支架所作的改进措施以及精馏塔加温吹扫的优化操作。     

Mutual determination of the solutions of problems of the description and analysis of special features of high-temperature creep of metallic materials

The article analyzes the problem of the necessity of systematizing the known data on the mechanical properties of heat-resistant steels and alloys with the object of improving the effectiveness of checking the possibilities of the constructed equations of state. It substantiates one of the variants of describing the regularities of instantaneous and short-term strain, creeps, stress relaxation, and creep limit from the same positions.