Classification of electrical measuring equipment

Conclusions The above problems for classifying electrical measuring equipments with respect to various characteristics of transformation and of converters which form part of electrical measuring instruments, reveal the extent of diversity in the design of modern measuring instruments. It should also be noted that all the above reasoning refers only to so-called measuring transducers which affect directly the properties and characteristics of instruments. In addition to the measuring converters, modern instruments also comprise supplementary converters, for instance, in the supply circuit, which function as rectifiers, stabilizers of the supply voltage, etc., thus still further complicating the design of the instrument.Hence, it is simply impossible to classify the electrical measuring instruments by their design, or by any single characteristic which determines the design of the instrument and its properties.In designing electrical measuring instruments, it is necessary to examine (or compile) a technical specification by means of all five classification features.The problem of selecting the type of input (receiving) and output conversion follows directly from the intended use of the instrument.Sometimes the instrument's application also determines the type of the input and output transducers.Having determined the type of conversion at the input and output of the Instrument, it is necessary to select the system of the measuring input transducer. Sometimes this problem has only a single possible solution, in other instances it is necessary to choose a system for the input receiving transducer from several possible systems.Now it becomes possible to select the type of modulation and the method of conversion by weighing up such technical and economic considerations as accuracy, frequency range, speed of operation, complexity of the design, possible cost, etc.Deceased.     

Implementation of an ANCF beam finite element for dynamic response optimization of elastic manipulators

Theoretical and practical aspects of an absolute nodal coordinate formulation (ANCF) beam finite element implementation are considered in the context of dynamic transient response optimization of elastic manipulators. The proposed implementation is based on the introduction of new nodal degrees of freedom, which is achieved by an adequate nonlinear mapping between the original and new degrees of freedom. This approach preserves the mechanical properties of the ANCF beam, but converts it into a conventional finite element so that its nodal degrees of freedom are initially always equal to zero and never depend explicitly on the design variables. Consequently, the sensitivity analysis formulas can be derived in the usual manner, except that the introduced nonlinear mapping has to be taken into account. Moreover, the adjusted element can also be incorporated into general finite element analysis and optimization software in the conventional way. The introduced design variables are related to the cross-section of the beam, to the shape of the (possibly) skeletal structure of the manipulator and to the drive functions. The layered cross-section approach and the design element technique are utilized to parameterize the shape of individual elements and the whole structure. A family of implicit time integration methods is adopted for the response and sensitivity analysis. Based on this assumption, the corresponding sensitivity formulas are derived. Two numerical examples illustrate the performance of the proposed element implementation.     

Inverse relationships for reflection diagnostics of uniaxially anisotropic nanoscale films on isotropic materials

The possibilities of determining the parameters of uniaxially anisotropic ultrathin nonabsorbing dielectric films on absorbing or transparent isotropic substrates by surface differential reflectance measurements are analyzed. The analysis is based on analytical reflection formulas obtained in the framework of a long-wavelength approximation. It is shown that, in the case of transparent substrates, it is always possible to determine the thickness of a uniaxially ultrathin film and its four parameters of anisotropy (optical constants n(o) and n(e) and angles θ and φ) simultaneously. However, for such films on absorbing substrates, it is possible to decouple the thickness and optical constants by differential reflectance measurements only if θ≠0. The accuracy of the obtained analytic formulas for determining the parameters of ultrathin films is estimated by computer simulations where the reflection problem was solved numerically on the basis of the rigorous electromagnetic theory for anisotropic layered systems.     

Classification of digital measuring instruments

Summary A classification schematic of digital instruments (Fig. 2) based on the above article includes the classification of digitizers by their method of comparing the unknown and known quantities, by the method used in measuring by their equipment and their output devices, that is, their method of presenting the results.The examination of the design principles of digital instruments only with respect to these classifications shows a considerable variety of measuring methods for which these instruments can be used. It should be noted, however, that the above classification does not include many derived types of digital circuits. However, digital instruments based on intermediate types may be of great importance. Thus, for instance, the simultaneous utilization of digitizers and analogue instruments, which is characteristic for differential methods of measuring the difference between a discrete and an unknown analogue quantity, is employed in a considerable number of instruments [5,7]. In the category of intermediate types of digital instruments should also be included partly automatic instruments which comprise contact and contactless elements, digitizers based on the simultaneous utilization of different methods of comparing the unknown and known quantities, etc.The proposed classification of digital instruments is undoubtedly not the only possible one. However, in our opinion, it covers the basic principles for designing digital instruments and indicates certain possible tendencies in their development.In conclusion the author considers it his duty to express his gratitude to Corresponding Member of the Academy of Sciences, USSR K. B. Karandeev and to Prof. M. I. Levin for their valuable advice, as well as to candidate of technical sciences B. S. Sinitsyn and engineers B. V. Karpyuka and A. N. Kasperovich for the useful observations made by them in discussing the material dealt with in this article.     

16th International Conference on Production Research (ICPR-16) Manufacturing-Service-People-Sustainable Systems

Robust design uses the ordinary least squares method to obtain adequate response functions for the process mean and variance by assuming that experimental data are normally distributed and that there is no major contamination in the data set. Under these assumptions, the sample mean and variance are often used to estimate the process mean and variance. In practice, the above assumptions are not always satisfied. When these assumptions are violated, one can alternatively use the sample median and median absolute deviation to estimate the process mean and variance. However, the median and median absolute deviation both suffer from a lack of efficiency under the normal distribution, although they are fairly outlier-resistant. To remedy this problem, we propose new robust design methods based on a highly efficient and outlier-resistant estimator. Numerical studies substantiate the new methods developed and compare the performance of the proposed methods with the ordinary dual-response robust design.     

Hardness testing in automatic and conveyor lines

Conclusions The above method seems to be the most promising at the present time, since it is free of the drawbacks characteristic of the Brinell and Rockwell methods (and hence, also, of instruments types TSh and TK), it lends itself to complete automation of hardness measurements, and to the provision for the hardness-measuring instruments of a recording chart in coordinates of load versus deformation.     

确定受压柱计算长度的通用图表

计算长度系数法仍是结构稳定验算的最常用的方法,用该法可避免复杂的整体结构的稳定计算,该法的核心是确定受压柱的计算长度,对此《钢结构设计规范》给出了一些相应的计算公式和表格,但这些公式和表格由于一些特定的假定有一定的适用范围,不适用于特殊情况下的柱的计算长度确定(不通用),对此该文对单根柱在各种不同约束情况下的计算长度系数进行了推导,并绘制成图表,这些图表不仅涵盖了规范公式和表格能求解的规则情况,而且还能确定非规则情况下柱的计算长度系数,图表使用方便、快速和直观。     

Multi-Objective Grey Wolf Optimization Algorithm for Solving Real-World BLDC Motor Design Problem

The first step in the design phase of the Brushless Direct Current (BLDC) motor is the formulation of the mathematical framework and is often used due to its analytical structure. Therefore, the BLDC motor design problem is considered to be an optimization problem. In this paper, the analytical model of the BLDC motor is presented, and it is considered to be a basis for emphasizing the optimization methods. The analytical model used for the experimentation has 78 non-linear equations, two objective functions, five design variables, and six non-linear constraints, so the BLDC motor design problem is considered as highly non-linear in electromagnetic optimization. Multi-objective optimization becomes the forefront of the current research to obtain the global best solution using metaheuristic techniques. The bio-inspired multi-objective grey wolf optimizer (MOGWO) is presented in this paper, and it is formulated based on Pareto optimality, dominance, and archiving external. The performance of the MOGWO is verified on standard multi-objective unconstraint benchmark functions and applied to the BLDC motor design problem. The results proved that the proposed MOGWO algorithm could handle nonlinear constraints in electromagnetic optimization problems. The performance comparison in terms of Generational Distance, inversion GD, Hypervolume-matrix, scattered-matrix, and coverage metrics proves that the MOGWO algorithm can provide the best solution compared to other selected algorithms. The source code of this paper is backed up with extra online support at and .     

岩体中爆炸破碎区半径计算方法讨论

岩体中爆炸破碎区半径是地下爆炸的重要参数之一。破碎区半径的常用计算方法有经验公式法、声学近似法和修正声学近似法等方法，这些方法计算结果的合理性有必要予以分析。选取辉长岩和大理岩2种岩体的典型参数值，用基于上述方法的4种计算公式，计算了集团装药耦合爆炸岩体的破碎区半径，但4种公式的计算结果存在较大差异。分析表明，基于声学近似法并采用波阻抗计算应力波衰减指数的计算公式，参数取值容易，计算结果合理，适合于实际工程应用。     

Shape functions and integration formulas for three-dimensional finite element analysis

Shape functions and numerical integration formulas for three-dimensional finite element analysis as found in most finite element reference books are incomplete. For example, shape functions and integration formulas for a pyramid with a quadrilateral base are missing. It is also difficult to find symmetric higher-order integration formulas for triangular and tetrahedral elements. In general, these shape functions and integration formulas cannot be satisfactorily derived as degenerate cases of shape functions and integration formulas for hexahedral (brick) elements. In this paper we present C°-continuous quadrilateral pyramid elements and integration formulas for two- and three-dimensional elements.     

Analytical solutions in eddy current testing of layered metals withcontinuous conductivity profiles

In this paper exact analytical expressions for the impedance of a cylindrical air-core coil above a layered metal structure whose conductivity varies continuously with depth are presented. Although the model is general, attention is focused on three conductivity profiles: the linear, the quadratic and the exponential. The derived expressions for the impedance change for each profile could provide a useful tool for the solution of the inverse problem: that of determining the conductivity from variable frequency measurements of the impedance. Furthermore, the obtained final formulas contain elegant mathematical functions and show a substantially higher computational efficiency with respect to existing methods     

Application of the packless piston principle to precision measuring instruments

Conclusions It follows from the above review that work in improving reference and calibrating instruments should be further developed. At the same time it is necessary to develop high-precision dead-weight piston instruments in order to satisfy the growing requirements of our national economy for precision instruments used in direct measurements under varying operating conditions, especially since the potentialities inherent in the principle of a packless piston provide the possibility for the successful solution of problems in the above field of measurements.     

A k, k-ε optimality selection based multi objective genetic algorithm with applications to vehicle engineering

In the paper, a multi objective genetic algorithm based on the concept of k-optimality and k-ε-optimality (KEMOGA) is introduced and applied. Pareto optimality alone is not always adequate for selecting a final solution because the Pareto optimal set can be very large. The k-optimality approach and the more general k-ε-optimality method, can be used to rank the Pareto-optimal solutions. The two methods have been included into a genetic algorithm selection procedure. The k-optimality method searches for points which remain Pareto-optimal when all of the subsets of n-k objectives (n is the number of objective functions) are optimised. The k-ε approach considers not only if an objective is worse than the others but also the entity of this variation through the introduction of a vector of indifference thresholds. The KEMOGA has been applied for the solution of two engineering problems. The selection of the stiffness and damping of a passively suspended vehicle in order to get the best compromise between discomfort, road holding and working space and a complex problem related to the optimisation of the tyre/suspension system of a sport car. The final design solution, found by means of the KEMOGA seems consistent with the solution selected by skilled suspensions specialists. The proposed approach has been tested and validated on a complex optimization problem. The solved problem deals with the optimization of the tyre/suspension system of a sport car. The proposed approach (KEMOGA) has shown to be very effective in terms of computational efficiency and accuracy.     

Measurement of small friction moments

Conclusions The most widespread methods of those examined by us for measuring small friction moments consist at present of the pendulum and calibrated spring methods for laboratory research, and of the self-braking method for industrial use. This difference is due to the fact that the self-braking method is speedier, but it can only determine the mean value of the friction moment over a given time interval, which is often insufficient for research work.The pendulum method possesses a theoretically high sensitivity; however, the measurement of small moments entails several technical difficulties, the most important of which is the impossibility of evaluating the moment due to the system's residual unbalance and to the error in determining arml. For measuring friction moments of 10^–3–10^–4g·cm preference should be given to the calibrated spring method with the rotation axis of the system beingplaced in the vertical position.An essential defect of mechanical methods for determining the instantaneous values of the friction moment consists in the limited range of the measured moments.By means of electromechanical methods it is possible to measure arbitrarily small friction moments. However, they have to be calibrated by means of mechanical instruments. Induction instruments are considerably simpler in design than those of the moving-coil type, but they are less sensitive and have a large relative error. The use of electromechanical instruments is most suitable for comparison measurements and for production testing, due to their high productive capacity.     

Computation of a ferrodynamic phase-meter circuit

Conclusions The above design formulas simplify considerably the computation of three-phase phase-meter components. The same technique can be applied for calculating single-phase phase meters; however, in such a case, the required phase difference in the instrument's parallel circuits is obtained by means of reactances.In case the measuring mechanism of a ratiometer has to be designed, the above design formulas and conclusions serve to select mechanism parameters which produce the best results.An experimental verification of the above method has shown adequate agreement between the computed data and those obtained by selection. Certain discrepancies (in the range of 10–20%) are due to dispersion in the ratiometer parameters produced in the course of its assembly.     

Variometric meters of rate of pressure variations (Review of US Patents)

Conclusions The simple design of a variometer as compared with other instruments and devices used for measuring the rate of pressure changes determines the promising possibilities of its application for measuring adequately large rates of change, that is, sufficiently high vertical velocities in ascent or descent. However, the considerable time constants of a variometer, which attain 4–8 sec, constitute its essential drawback.Variometers can also be used for measuring small rates of pressure changes. However, in that case it becomes necessary to measure small pressure differences and, therefore, it is essential to increase the size of the elastic element and the volume of the chamber, thus leading to a considerable rise in the instrument's time constant. Moreover, the designing of variometers for measuring small rates of pressure changes leads to a sharp rise in their dimensions and weight.The existing methods of compensating the retardation error of variometers as well as their temperature and height errors provide satisfactory results, although they do not completely eliminate these errors and, moreover, in the majority of cases they considerably complicate the design of variometers.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 31–34, April, 1969.     

Analysis of the results of checking gauges and instruments

Conclusions Rational values of the permissible errors can be established only by analyzing the probable checking scrap. The latter is determined by technical and economic considerations which include: a) the permissibility of a certain small percentage of unsatisfactory instruments remaining in circulation, b) the permissibility of condemning a certain percentage of serviceable instruments, c) the cost of a checking method which reduces to the required small dimensions or eliminates scrap.No general relation between the permissible errors in the tested and reference measures or instruments is possible.A rational and reliable selection of permissible errors and methods of checking is only possible when sufficient data is available on the error distribution laws in the manufactured measures and instruments. The provision of such data should be one of the primary objects in testing standard instruments.Everything stated above refers to large scale testing of mass produced measures and measuring instruments when the aggregate of both the tested and reference measures and measuring instruments is sufficiently large. Above methods of calculations, however, are applicable to small groups of reference measures and instruments. In that case, however, it is necessary to use the discrete distribution of probable error densities which corresponds to the given number of instruments and their errors. Such a case could occur in evaluating checking results in any laboratory with a small number of reference measures or instruments. Such an evaluation is, of course, only possible if the errors of the available measures are determined with sufficient accuracy by more accurate methods than those normally used in checking these measures.     

Methods,models, and budgets for estimation of measurement uncertainty during calibration

Basic models are given for the interaction of instruments to be calibrated and standard measuring instruments as a combination of two types of measuring instruments with three methods for transfer of the unit value. Model equations for additive correction, correction multipliers, and correction dividers (degrees of recovery) are written down. The uncertainty budgets are compared and formulas for the combined and expanded uncertainty for all these types of correction are derived.     

Photocompensated amplifiers with torsion-suspension galvanometers

Conclusions The above investigations have shown that in order to decrease drastically the galvanometer's sensitivity to shock it is necessary to suppress or prevent transverse oscillations of its moving part. This can be achieved by the use of transverse oscillation dampers.Magnetic induction dampers, for instance, can be used. Transverse oscillations occur almost exclusively in the direction of the least stiffness of suspensions, thus facilitating the design of magnetic induction dampers.However, liquid dampers seem to be more promising. Such damping can be achieved either by immersing the whole moving part in a liquid, or by means of concentrated drop dampers [7]. Preliminary experiments have shown the great efficiency of liquid dampers. It would appear that the use of such dampers in the control galvanometers of photocompensated systems will make it possible to use these instruments under the most difficult operating conditions.     

Measurements of Viscoelastic Functions of Polymers in the Frequency-Domain Using Nanoindentation

A method to measure the complex compliance (or modulus) of linearly viscoelastic materials is presented using nanoindentation with a spherical indenter. The Hertzian solution for an elastic indentation problem, in combination with a hereditary integral operator proposed by Lee and Radok (Journal of Applied Mechanics 27, 1960, 438–444) for the situation of non-decreasing indentation contact area, was used to derive formulas for the complex viscoelastic functions in the frequency-domain. The formulas are most suitable for frequencies lower than a frequency limit such that the condition of non-decreasing contact area holds; they are reasonably good approximation at higher frequencies under which decreasing contact area occurs and the Ting (Journal of Applied Mechanics 33, 1966, 845–854) approach for arbitrary contact area history is needed. Nanoindentation tests were conducted on both polycarbonate and polymethyl methacrylate under a harmonic indentation load superimposed on either step or ramp indentation load, while the resulting displacement under steady state was recorded. The load and displacement data at each frequency were processed using the derived formulas to determine the viscoelastic functions in the frequency-domain. The same materials were also tested using a dynamic mechanical analysis (DMA) apparatus to determine the complex viscoelastic functions. The DMA and nanoindentation results were compared and found in a good agreement, indicating the validity of the new method presented.