Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

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.     

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.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

水线震荡对斜拉桥拉索风雨激振稳定性的作用

从理论和试验两个方面研究了水线震荡对斜拉桥拉索风雨激振稳定性的作用。建立了拉索和水线的运动方程，应用李雅普诺夫函数给出了水线不平衡角的判别公式。设计了一种新型的带有可运动人工水线的拉索模型，并进行了风洞试验。理论和试验结果表明，水线震荡是导致拉索风雨激振具有较大不稳定范围的主要原因。试验结果证明了理论模型和分析的结果是正确的。     

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。     

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.     

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.     

Analysis of anisotropy of properties on the basis of studies of texture of coarse-grained ingots of thermoelectric materials

An analysis of anisotropy of the properties of a Bi₂Se_0.3Te_2.7 solid solution was carried out using construction of demonstrative surfaces for thermoelectric effectiveness and thermal expansion coefficients. It is shown that the texture is an important factor forming anisotropy of properties and technological fitness of ingots for manufacturing modules. Anisotropy of properties based on the studies of the ingot textures obtained using the float-zone method and Bridgman method (growing thermoelectric plates in a flat cavity) was studied.     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

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.     

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.     

射面交叉分析及武器控制方法研究

通过对影响多武器同时射击安全的重要因素——射面交叉的研究，分析了产生射面交叉的原因，建立了射面交叉的判断模型，研究了控制武器的方法，建立了禁止射击信号的产生模型。研究结果对舰艇的总体设计、武器控制以及作战使用有一定的指导意义。     

微生物降解苯酚的研究进展及其工程菌的应用前景

概述了苯酚的生物降解途径和几株降解菌的基因组成及其作用机制，提出了生物降解的调控模式，并讨论了工程降解菌的构 建及应用前景。     

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.     

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.     

Mechanism of Inhibition of Corrosion of Steel in the Presence of Sulfate-Reducing Bacteria

We consider the electrochemical and microbiological aspects of microbe-induced corrosion of low-carbon steels caused by sulfate-reducing bacteria and its inhibition by organic surfactants. We propose relations that take into account the influence of the main products of the vital activity of sulfate-reducing bacteria (H₂S and HS^–) on the cathodic and anodic reactions of the corrosion process. The evaluation of the adsorption properties of organic surfactants and analysis of their influence on the kinetics of oxidation-reduction reactions enable one to develop high-performance inhibitors of microbe-induced corrosion of steels in aqueous aggressive media containing sulfate-reducing bacteria.     

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.     

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。     

空分设备冷箱的钢结构设计浅析

空分设备冷箱需要为内部设备提供一个超低温环境,对空分设备的安全运行有直接影响。介绍空分设备冷箱的工作特点以及冷箱钢结构设计的基本要点,详细说明了冷箱钢结构设计流程,并提出空分设备冷箱应该作为一个特殊的建筑物来进行设计和监管。