Industrial Arc Instrumentation

Hitherto the instrumentation of moving arcs has been neglected and photographic methods have mainly been used to determine arc velocities. Furthermore, previous arc research has been confined, in the main, to high-speed arcs (greater than 10 ft/s) in circuit breaking and similar applications. This paper considers, for the first time, the slowly moving arc (about 1 ft/min) associated with such industrial processes as welding, profile cutting, zone refining, etc. New arc instrumentation methods have been developed for these arc velocities. They use analog and digital techniques. These new methods are simple, yet sufficiently accurate for sophisticated industrial applications. Typical results are given.     

微机数字图象处理系统用于甲皱微循环流速的测量

微血管中血细胞流速是反映微循环状态与特征的一个十分重要的参数。国内外许多医学工作者都十分关心这个参数的测定工作。本文介绍用微机数字图象处理系统测量微血管中血细胞流速的装置和测量方法,并给出了校验测试和临床测试结果。校验测试结果表明,系统测量结果准确可靠;临床测试结果与目前国内外临床检测所给出的结论是一致的。     

散热器散热过程的场协同分析

大型计算机服务器CPU的散热问题始终是业内专家关注的焦点,为此推出了多种不同类型的CPU散热装置。为了提高散热器对流换热的性能除了采用强化换热措施外,流体速度场与温度梯度之间的协同程度也将影响其换热效果。本文对一种新型结构的芯片散热器进行了实验研究,通过PIV实验测试以及运用流固耦合进行数值计算,获取了实验风道中散热器周围的速度场和温度场。在此基础上利用场协同理论对其换热过程进行了分析,得出了颇有参考价值的研究结论。     

Automatic Self-Certification of a Computer-Controlled Calibration System

The theory, techniques, and apparatus that are used to perform an automatic self-certification of a computer-controlled calibration system are described. This process determines the linearity and bias deviations of the instrumentation of the system. These deviations are stored in the digital computer for subsequent use as corrections to the nominal instrument values when the system is applied to external devices. Dc measurements and stimuli, the uncertainties of which are of the order of 0.001 percent, have been achieved using this technique, exceeding the specifications normally associated with the uncorrected instrumentation. A similar reduction in uncertainty results from the self-certification process in ac voltage and resistance measurements. Using a 1-volt dc source, 1000-ohm resistor, and ac-dc thermal transfer as references, the scales of measure are automatically reestablished over a wide dynamic range in less than five minutes. Laboratory applications of this computer-controlled system have been made to classical metrology problems that include measurements of standard resistors, saturated standard cells, and resistance thermometers. Semi-automatic calibrations of test and measuring instruments have been performed to demonstrate potential productivity and accuracy.     

Instrumented and Computer Interfaced Single Punch Tablet Press for the Rapid Evaluation of Compression and Lubrication Behaviour

A low cost instrumented and computer interfaced single punch tablet press was developed for the rapid data aquisition of compression and lubrication properties of powders arid processed materials.

A Manesty type F3 tablet machine has been modified to enable the fitting of piezo electric load cells to both upper and lower punch assemblies. The paper describes how the modifications permit interchangability of a range of punch sizes and shapes and yet ensure good accuracy and reproducibility of compression end lubrication data.

The instrumentation is interfaced with a dedicated A. I. M. 65 microcomputer for the rapid conversion of the instrumentation outputs into compression force units and for statistical evaluation. The computer software also incorporates a novel method for the evaluation of lubrication properties from a single or a series of pre-determined compression events, using the some sensitivity for force measurement from the lower punch lord cell.

The compression data and the physical properties of the compacts can be stored and retreived as fingerprints using a P. E. T. microcomputer and a digital plotter. A date bank may then be developed for the evaluation of raw materials, product development, monitoring of production performance and trouble shooting.

The paper further describes the evaluation of new lubricants in comparison with magnesium stearate using the instrumentation described.     

Instrumented and Computer Interfaced Single Punch Tablet Press for the Rapid Evaluation of Compression and Lubrication Behaviour

A low cost instrumented and computer interfaced single punch tablet press was developed for the rapid data aquisition of compression and lubrication properties of powders arid processed materials.

A Manesty type F3 tablet machine has been modified to enable the fitting of piezo electric load cells to both upper and lower punch assemblies. The paper describes how the modifications permit interchangability of a range of punch sizes and shapes and yet ensure good accuracy and reproducibility of compression end lubrication data.

The instrumentation is interfaced with a dedicated A. I. M. 65 microcomputer for the rapid conversion of the instrumentation outputs into compression force units and for statistical evaluation. The computer software also incorporates a novel method for the evaluation of lubrication properties from a single or a series of pre-determined compression events, using the some sensitivity for force measurement from the lower punch lord cell.

The compression data and the physical properties of the compacts can be stored and retreived as fingerprints using a P. E. T. microcomputer and a digital plotter. A date bank may then be developed for the evaluation of raw materials, product development, monitoring of production performance and trouble shooting.

The paper further describes the evaluation of new lubricants in comparison with magnesium stearate using the instrumentation described.     

Accuracy limitations of FOG-based continuous measurement-while-drilling surveying instruments for horizontal wells

Horizontal drilling processes in the oil industry utilize directional measurement-while-drilling (MWD) instruments to provide real-time monitoring of the position and the orientation of the bottom hole assembly (BHA). It has been reported that a single fiber optic gyroscope (FOG) can be incorporated with three-axis accelerometers to provide real-time MWD surveying of horizontal wells. However, the long-term performance and the accuracy limitations of this FOG-based instrumentation system have not been discussed. This article aims at describing a methodology for quantitative long-term analysis of the various surveying errors while drilling the near-vertical sections of the well. It also offers some techniques to enhance the long-term surveying accuracy in an experimental model of the FOG-based downhole-surveying instrument. The surveying errors are optimally estimated by the Kalman filtering techniques, and their long-term analysis is based on studying the corresponding mean square estimation errors. In order to limit the long-term growth of the surveying errors, we suggest improving the velocity computation provided by the FOG-based system either by continuous velocity update or by zero velocity update at some predetermined surveying stations. These techniques have significantly limited the long-term growth of the position errors (less than 100 m over a more than 2-h experiment). Moreover, the errors associated with the BHA orientation components were kept at less than 1/spl deg/. Suggested methodology significantly improved the surveying accuracy in an experimental model of the FOG-based MWD surveying system.     

基于视觉生理反应指标的工业系统人机界面出错因子提取研究

为了降低用户在操作数字化仪控系统交互界面的认知负荷，降低用户在操作数字化仪控系统交互过程中的出错率，进行眼动追踪实验。实验以核电厂监控任务界面为样本，运用凝视与扫视生理反应指标，对数字化仪控系统交互界面的信息特征布局进行探究。基于对实验数据的结果分析得出，用户在数字化仪控系统交互界面视觉认知过程中，会产生信息疏漏、误读/误判等出错因子，并通过提取用户在操作过程中产生的出错因子，为数字化仪控界面的设计提供参考依据。基于设计认知过程中出错因子的交互界面设计对减少任务的出错率和提升交互界面的认知绩效具有一定的参考价值。     

10th Annual IEEE Instrumentation and Measurement TechnologyConference - IMTC '93

The following topics were dealt with: sensors and transducers; quantisation and A/D convertors; time measurement; frequency measurement; digital signal processing; data acquisition; integrated measurement structures; system identification; computer measurement and software; robotics; artificial intelligence and fuzzy logic; medical instrumentation; microwaves; optics and fibre optics; metrology; and miscellaneous measurements     

Energy Consumption Estimation in Embedded Systems

This paper presents an energy consumption modeling technique for embedded systems based on a microcontroller. The software tasks that run on the embedded system are profiled, and their characteristics are analyzed. The type of executed assembly instructions, as well as the number of accesses to the memory and the analog-to-digital converter, is the required information for the derivation of the proposed model. An appropriate instrumentation setup has been developed for measuring and modeling the energy consumption in the corresponding digital circuits.     

Improved Electric Arc Furnace Operation Via Implementation of a Geno-Fuzzy Control System

The U.S. steel industry is growingly increasingly interested in the process of slag foaming in their electric arc furnace plants. Although slag foaming has been shown to improve plant efficiency, this highly dynamic process can be very difficult to consistently control. This article describes a computer control system developed to effectively manipulate the slag foaming process, and the implementation of the controller in an electric arc furnace plant. The control system is a model-following controller based on fuzzy logic. It uses a neural network to simulate the slag foaming process. Furthermore, the control system uses an evolutionary algorithm to effectively tune its fuzzy rule base in response to the dynamic behavior of the slag foaming process. Results are presented, which demonstrate the effectiveness of the control system in this process characterized by relatively slow process dynamics.     

Erosion of a Copper Cathode in a Nonstationary Arc Spot. I. Experimental Investigation

A study has been made of the dependence of the erosion of a copper cathode of an electricarc heater on the basic operating parameters: the arc current, the velocity of movement of an arc spot, and the temperature of the electrode surface. The experiments were conducted in a coaxial electricarc heater with a magnetic movement of the arc in an air medium for an arc current of 95–480 A and a magnetic field of 0.005–0.417 T. The duration of the experiment, the axial velocity of a plasmaforming gas, and the flow rate of a cooling water were held constant. It has been shown that there are two different erosion regimes: the microerosion regime characterized by a weak dependence on the current and the macroerosion regime with a strong dependence on the current; the transition from one regime to the other is realized upon the attainment of the critical value of the current, dependent on the magnetic field and the thermal regime of the electrode. The existence of a velocity interval in which the specific erosion is minimum has been shown, which confirms the predictions of the earlier thermal model of erosion of cold electrodes.     

An instrumentation system using combined sensing strategies for online mass flow rate measurement and particle sizing

Online concurrent measurement of mass flow rate and size distribution of particles in a pneumatic suspension is desirable in many industries. This paper presents the basic principle of and initial results from a novel instrumentation system that uses a combination of electrostatic and digital imaging sensors in order to achieve these goals. An inferential approach is adopted for the mass flow measurement of particles where velocity and volumetric concentration of particles are measured independently. The velocity of particles is determined by cross-correlating two signals derived from a pair of electrostatic sensors, while the volumetric concentration of particles is obtained using a novel digital imaging sensor, which also provides particle size distribution data. The basic principles and limits of operation of the imaging sensor are discussed and explained. Results obtained from a pneumatic conveyor system are presented that show good performance of the system for both mass flow metering (accurate to about /spl plusmn/4%) and particle sizing (reliable to around /spl plusmn/0.5%). A particle size distribution result is also included, and the insensitivity of particle sizing to changes in velocity and concentration is assessed. In general, the results obtained are encouraging, and the system shows great promise.     

A 12-camera body scanning system based on close-range photogrammetry for precise applications

A precise 3D body scanning system, designed for applications in the medical and biomedical field, is described. The system consists of 12 digital cameras, mounted on a rigid frame which maintains the B/H ratio constant. An LED lighting system, integrated with the rigid frame, ensures a homogenous illumination of the subject. A modified firmware installed on each device enables the synchronised remote release driven by remote control. Data transmission to the computer is carried out wirelessly. A process for the estimation of the extrinsic camera parameters has been implemented with the aim of obtaining a 3D model in 1:1 scale. Analyses have been performed in order to state the repeatability of the process used to estimate the external camera calibration parameters as well as the precision of the 3D digital models of a body obtained for a mannequin and for a live human subject.     

Curvilinear Bicubic Spline Fit Interpolation Scheme

When the digital computer is used to design an optical system, the solution is obtained at a set of grid points over a given plane. A reliable interpolation technique is then required to find the values between the grid points, and the bicubic spline fit interpolation technique is often used for this purpose. When the system geometry is circular, a polar grid pattern is usually preferable to a rectangular or triangular grid pattern, especially when the behaviour of the computed function is strongly dependent on the boundary conditions along the circumference of the circular system. The currently available bicubic spline fit interpolation scheme for the rectangular coordinate system is not suitable for use with a polar grid pattern and must therefore be modified. In developing the modified interpolation scheme, a feature of physical significance has been added and is based on the fact that all physical laws are formulated with length as the basic unit. Because the functions to be interpolated are usually the physical quantities, the interpolation scheme presented in this paper uses the radial length (r ¥) and the arc length (r ¥ r ¥ /) as the bases of the interpolation and implicitly takes account of the shape of the patch, which is a wedge or truncated wedge. This approach of using the arc length represents a distinct departure from that which essentially substitutes r, / variables in the polar coordinate system for x y variables in the rectangular coordinate system.     

Electrical and magnetic techniques for monitoring arc behaviour during VAR of INCONEL1 718: Results from different operating conditions

Novel instrumentation and computer modelling are described which have been developed to detect and interpret current flows and magnetic fields during VAR. Results from different operating conditions during VAR of 20″ diameter ingots of INCONEL 718 at Special Metals Wiggin Ltd., Hereford are presented and discussed with reference to macrostructural findings. It is shown that the results support the viability of the measurement techniques, and that the techniques are capable of detecting subtle changes in arc behaviour. Freckles were formed under one set of experimental conditions, and it is shown that the distribution of the radial location of the arc centre (obtained from the magnetic field analysis) may help to explain this.     

Simultaneous measurements of dynamic values using the transit timemethod

The problem of simultaneous and accurate measurements of two dynamic values, time dependencies of flow velocity and ultrasound velocity in the flow, is analyzed. In order to measure two dynamic values simultaneously a theory of the transit time method has developed, and the theoretical model of a microprocessor-based measuring system has been derived. The ways to improve the accuracy and information of such dual-channel measurement systems have been examined. It is shown that invariance between two channels of a measurement system can be achieved when dynamic, nonlinear, parametric models of these channels are identified in real time during the process of measurement, and when the multipulse irradiation of flow is used. The results of computer simulation of transit time method dynamic errors are represented. A method of minimizing these errors has been proposed     

Ultralow-noise PC-Based measurement system for the characterizationof the metallizations of integrated circuits

The design, realization, and test of a multichannel ultralow-noise data acquisition system are described in this paper. The instrument, controlled by a personal computer (PC), has been specifically designed for performing low-frequency noise measurements on interconnect lines of an integrated circuits. A specifically designed ultralow-noise preamplifier has been realized and an optical link has been used for connecting the front-end of the instrument with the PC in order to minimize the effects of electromagnetic interferences. An overall background noise some orders of magnitude below that of preexisting instrumentation has been obtained. In particular, the power spectral density of the equivalent input voltage noise was 1.5, 3, 10 nV/(Hz)^1/2 at 1, 0.1, and 0.01 Hz, respectively     

An analytical approach to quantitative effect estimation of operation advisory system based on human cognitive process using the Bayesian belief network

The design of instrumentation and control (I&C) systems for nuclear power plants (NPPs) is rapidly moving towards fully digital I&C systems and is trending towards the introduction of modern computer techniques into the design of advanced main control rooms (MCRs) of NPPs. In the design of advanced MCRs, human–machine interfaces have improved and various types of decision support systems have been developed. It is important to design highly reliable decision support systems in order to adapt them in actual NPPs. In addition, to evaluate decision support systems in order to validate their efficiency is as important as to design highly reliable decision support systems. In this paper, an operation advisory system based on the human cognitive process is evaluated in order to estimate its effect. The Bayesian belief network model is used in the evaluation of the target system, and a model is constructed based on human reliability analysis event trees. In the evaluation results, a target system based on the operator's cognitive process showed better performance compared to independent decision support systems.     

Calculation of the properties of digital mammograms using a computer simulation

A Monte Carlo computer model of mammography has been developed to study and optimise the performance of digital mammographic systems. The program uses high-resolution voxel phantoms to model the breast, which simulate the adipose and fibroglandular tissues, Cooper's ligaments, ducts and skin in three dimensions. The model calculates the dose to each tissue, and also the quantities such as energy imparted to image pixels, noise per image pixel and scatter-to-primary (S/P) ratios. It allows studies of the dependence of image properties on breast structure and on position within the image. The program has been calibrated by calculating and measuring the pixel values and noise for a digital mammographic system. The thicknesses of two components of this system were unknown, and were adjusted to obtain a good agreement between measurement and calculation. The utility of the program is demonstrated with the calculations of the variation of the S/P ratio with and without a grid, and of the image contrast across the image of a 50-mm-thick breast phantom.