流出杯式粘度计校正系数的测量不确定度评定

文章介绍了流出杯式粘度计校正系数的不确定度评定并给出结果.     

CNAS M0040工作毛细管粘度计(平氏)校准结果不确定度分析

通过分析工作毛细管粘度计(平氏)粘度计常数校准过程中各分量引入的测量不确定度来源,对工作毛细管粘度计(平氏)粘度计常数的各测量不确定度分量进行了量化,确定标准粘度液和流出时间是粘度计常数校准的主要影响因素。评定结果为粘度计常数的相对合成标准不确定度为0.1%,扩展不确定度为0.2%(k=2)。     

流出杯式黏度计不确定度评定及校准能力验证

正目前,全国有上百家校准实验室建立了黏度计检定装置,可对毛细管黏度计、旋转黏度计及流出杯式黏度计进行检定/校准。本次能力验证计划主要是对各实验室流出杯式黏度计的校准能力和水平进行验证,评价实验室对该类仪器的校准能力。本次计划依据JJG743-1991《流出杯式粘度计检定规     

正压进气法钟罩检定音速喷嘴的研究

以钟罩式气体流量标准装置基准,采用正压进气法,对三只不同小口径音速喷嘴进行了不同背压比下的实验,对实验数据进行了分析,并对流出系数进行了不确定度分析。其中重复性误差最大喷嘴的流出系数不确定度为0．13％,扩展不确定度为0．26％。     

粘度的动能校正和毛细管粘度计的选用

本文计算了不同型号毛细管粘度计的运动粘度测量范围,确定了不同动能相对校正值时的流出时间下限和不同流出时间时的流出时间改正值以及流体的层流流出时间,这对毛细管粘度计的标准设计和正确使用提供了可靠依据。     

流出杯式黏度计测量值的不确定度评定方法研究

本文针对流出杯式黏度计的计量特性,对其中的标准黏度液流出时间等重要参数的测量数据进行分析,并对其测量值的不确定度进行了评定。     

低雷诺数临界流喷嘴的校准不确定度评定

低雷诺数临界流喷嘴用于膜式燃气表示值误差的检定.文章首先阐述了检定临界流喷嘴流出系数的气体活塞式校准器结构、工作原理.然后根据检定方法和数学模型,对不确定度来源进行分析评定,通过实验举例给出典型临界流喷嘴流出系数及其扩展不确定度.采用气体活塞式校准器动态检定临界流喷嘴流出系数,其扩展不确定度可达0.15%,重复性优于0...     

临界流文丘里喷嘴测量不确定度分析

文章介绍了临界流文丘里喷嘴的工作原理,以及用pVTt法气体流量标准装置检定临界流文丘里喷嘴流出系数时的不确定度分析。对于检定过程的不确定度问题,列出了理想条件下的临界流量、实际条件下的临界流量以及喷嘴流出系数不确定度等的测量模型。并对检定过程中喷嘴流出系数的相对扩展不确定度进行了详细的评定,分析了各个因素的来源,便于在实际工作中分析影响测量不确定度的主要因素,从而提高我们校准工作的准确度和可靠性。     

差压式流量计测量不确定度的经验估计

本文在分析差压式流量计流出系数特性的基础上,提出了估计差压式流量计测量不确定度的衫方法,对差压式流量计的具体应用具有指导意义。     

毛细管粘度计法测量运动粘度的不确定度评定

利用毛细管粘度计法测定分析纯乙二醇的运动粘度,建立测量模型,分析和识别了影响测量不确定度的因素,并根据JJF 1059.1—2012《测量不确定度的评定与表示》对各不确定度分量进行了量化估计。结果表明,毛细管粘度计法测定运动粘度的不确定度主要来源于测量重复性和粘度计常数。     

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.     

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.     

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.     

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.     

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。     

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.     

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.