Development and application of spectacles frame parameter measurement apparatus

The measurement of the spectacles frame parameters has substantial effects on both the production and export of spectacles products. In fact, this measurement is the measurement of related three-dimensional trajectory. The working principles of the measurement apparatus developed based on capacitive grating technology are introduced in this paper. Capacitive grating technology is a precision length measurement method. Its advantages are small volume, low price, low production cost, and easy to obtain apparatus is composed of one industrial control computer, tem stability is guaranteed during the design of the circuit into account. The software is divided into lower layer and precise readings of the measured data. The measurement two microcontrollers and corresponding circuits. The syswith the practical situation of upper layer. Each layer has its industry application taken different emphasis. The causes of system errors and the method of error elimination are also analyzed. The analysis of the data obtained from experiments and the operating results of prototype apparatus both indicate that the proposed measurement apparatus has achieved outstanding competitive technical level of same kind products in international market and thus has ideal implications for mass production.     

A self-heating 2ω method for Seebeck coefficient measurement of thermoelectric materials

A novel and reliable self-heating 2ω method has been developed to measure the Seebeck coefficient of the microscale/nanoscale thermoelectric materials. Based on the analytical solution of the transient heat-conduction equation of the specimen heated by a harmonic current, two measurement modes have been developed: (1) the Seebeck coefficient can be directly extracted from the ratio of experimentally measured 2ω Seebeck voltage to theoretically predicted 2ω temperature drop oscillation; and (2) the Seebeck coefficient can be steadily extracted from the measured 2ω and 3ω voltages. This approach has been applied to a 25.4 μm thick K-type thermocouple and the measured Seebeck coefficient corresponds well with the nominal value.     

Erratum to “Analysis of optical and wetting properties of a biomimetic antireflective surface for practical application”

Journal of Mechanical Science and Technology -     

Present Situation and Forecast for Development of Rubber Injection Press

The rubber injection moulding machinery is one of the three major moulding machines in the industrial moldedrubber articles. It is only inferior to the rubber curing press （hot molding machine） in quantity, but is far higher than the rubber transfer injection molding machine （injection moulding machine）, and occupies the 1/4 above share of the total amount. At present, the capacity of the rubber injection moulding machine all over the world estimates for 30,000-40,000 at least, the amount of rubber consumed is above 60% - 70% of the molded rubber articles, and became the main equipment of the rubber products for automobile, electronics and so on.     

A macro–micro compensation method for straightness motion error and positioning error of an improved linear stage

The International Journal of Advanced Manufacturing Technology - This research developed a linear stage with improved structures for reducing the error sources and proposed a macro–micro...     

Development of a Setup for the Discrimination of β+ and γ Rays

Abstract

A β⁺–γ discrimination set‐up was developed and applied to the ²²Na radioisotope. The radioisotope emits positrons (β⁺) and these positrons create γ rays by annihilating with electrons. These annihilation γ rays were used here, and the discrimination between these positrons and γ rays was investigated by the coincidence measurement between time signals and the energy signals. The detection system presented here uses a 3 inch (diameter) by 3 inch (length) NaI(Tl) inorganic scintillation detector for γ detection and 3 inch (diameter) by 3 inch (length) plastic scintillation detector for β⁺ detection.     

Accurate measurement method for tube’s endpoints based on machine vision

Tubes are used widely in aerospace vehicles, and their accurate assembly can directly affect the assembling reliability and the quality of products. It is important to measure the processed tube’s endpoints and then fix any geometric errors correspondingly. However, the traditional tube inspection method is time-consuming and complex operations. Therefore, a new measurement method for a tube’s endpoints based on machine vision is proposed. First, reflected light on tube’s surface can be removed by using photometric linearization. Then, based on the optimization model for the tube’s endpoint measurements and the principle of stereo matching, the global coordinates and the relative distance of the tube’s endpoint are obtained. To confirm the feasibility, 11 tubes are processed to remove the reflected light and then the endpoint’s positions of tubes are measured. The experiment results show that the measurement repeatability accuracy is 0.167 mm, and the absolute accuracy is 0.328 mm. The measurement takes less than 1 min. The proposed method based on machine vision can measure the tube’s endpoints without any surface treatment or any tools and can realize on line measurement.     

Development of free vibration analysis algorithm for beam structures by combining Sylvester’s inertia theorem and transfer stiffness coefficient method

A new free vibration analysis method, which is called the Sylvester-transfer stiffness coefficient method (S-TSCM), is developed by combining Sylvester’s inertia theorem and the transfer stiffness coefficient method. In this paper, the free vibration analysis algorithm of a straight-line beam structure is formulated by S-TSCM. From the computation results of the free vibration analysis for the three types of beam structures, we confirm that S-TSCM is a very effective method. In particular, S-TSCM is superior to both the transfer stiffness coefficient method and the transfer matrix method in terms of computational accuracy and time. In the free vibration analysis for the beam structure with a large number of degrees-of-freedom, S-TSCM is superior to the finite element method in terms of computational time and storage.     

Development and Evaluation of Greases for High Temperature—High Speed Applications

Greases capable of lubricating antifriction bearings in aircraft accessory components operating at temperatures up to 600 F and at speeds between 20,000 and 45,000 rpm under light loads are required by the military. Some of the phases of a development program on greases for this application are discussed. The phases covered include criteria and methods of evaluation for the fluid and thickener components for greases, test equipment, and methods of test for determining the performance life of greases, and the current status of the development program.     

Comparative study of electrostatic sensors with circular and probe electrodes for velocity measurement of pulverised coal

This paper presents recent progress on the velocity measurement of pulverised coal in pneumatic pipelines using electrostatic sensors in combination with correlation signal processing techniques.A comparative study of electrostatic sensors with circular and probe electrodes was conducted on a 94 mm bore horizontal pipeline in a 4 MW furnace.The advantages and limitations of both sensors are discussed.Experimental results demonstrate that both sensors are capable of providing pulverised coal velocity measurement with excellent repeatability and dynamic response.     

Ultrasonic method for determination of elastic moduli—Numerical simulation and experimental results

In this work, a numerical simulation and experimental results using a modified prism technique are presented. It is based on pulse-echo technique and involves the measurement of both longitudinal and transversal waves velocities in trapezoidal-prism shaped specimens with only one transducer. Both longitudinal and transversal waves are generated through mode conversion at the interface between water and the specimen under test. Based on numerical simulation with the 2-D Elastodynamic Finite Integration Technique (EFIT), several snapshots are generated to illustrate the functionality of this new technique, and the experiment was performed on cement paste with various water/cement ratios.     

A signal interpolation method for Fabry–Perot interferometer utilized in mechanical vibration measurement

In this investigation, a self-developed signal processing method for Fabry–Perot interferometer is proposed which can be utilized for high-speed dynamic displacement measurements, e.g. mechanical vibration measurements. The lookup table (LUT) integrated with the interference intensity equation has been employed for the interpolation processing of interference signals. With the aid of this method, the interpolation error has been reduced by 40% in comparison with that resulting from the commercial sinusoidal signal processing module. By operations of Fast Fourier Transform (FFT), the displacement measurement distribution can be converted into the frequency spectrum diagram. The interpolation resolution of the proposed interferometric displacement measurement system is about 0.1 nm. Experimental results demonstrate that this interferometer system is available for measuring frequencies till 2 kHz where its corresponding amplitude is 0.15 μm.     

Ludwik Finkelstein and measurement – A challenge for the future

A brief reflection on the contribution of Ludwik Finkelstein and, echoing his own words, the continually changing and developing response to the push of advancing technology and the pull of changing requirements, setting a challenge for education in the field of measurement and instrumentation for future generations.     

LED luminance measurement and development of low-cost computerized perimeter

An accurate method has been developed to calculate and measure the luminance of light-emitting diode （LED）. A novel, simple-structured and high-precision circuitry was designed, which has been applied to the development of a low-cost threshold static automated perimeter. Round LEDs of 2 mm in diameter were used as stimuli. A logarithmic scale is used to express the differential light sensitivity, where 0 dB represents the brightest stimulus that corresponds to 1 000 asb. The LED radiant power was measured and its equivalent luminance was calculated by the derived equations. The schematics of the system is given, together with a novel circuitry for selecting stimulus point and its luminance. Initial clinical trial results were promising,which led to a further development of a commercial product.     

Experimental validation of the calculation of phase holdup for an oil–water two-phase vertical flow based on the measurement of pressure drops

The performance of metering the phase holdup of an oil–water two-phase vertical flow has been investigated based on the measurement of the gravity and frictional pressure drops. A U-tube, in which the same flow patterns can be obtained in downward and upward vertical flows, is designed to measure both gravity and fractional pressure drops. During the experiments, the mixture velocities of the oil and water are in the range of 0.28–4.65 m/s and the oil volume fraction from 0 to 1.0. The results show that the oil holdups calculated are satisfactory with the absolute error of ±10%. The method presented in this work can be used to verify the results of tomography due to its simplicity and therefore is sufficient enough to be applied in industry.     

A practical control method for precision motion—Improvement of NCTF control method for continuous motion control

The present paper describes a practical control method for a precision motion system and the performance thereof. For practical use, high motion control performance and ease of design and controller adjustment are desired. A nominal characteristic trajectory following control (NCTF control) has been investigated to realize high performance and ease of application of point-to-point (PTP) positioning. The controller comprising a nominal characteristic trajectory (NCT) and a PI compensator is free from exact modeling and parameter identification. In the present paper, the NCTF control is modified in order to improve the control performance of continuous motions such as tracking and contouring motions. The NCTF controller for continuous motion (referred to as Continuous Motion NCTF controller) has a structure that is almost identical to the conventional NCTF controller and is designed using the same design procedure. The Continuous Motion NCTF controller is applied to ball screw mechanisms, and its motion control performance is evaluated from the experimental tracking, contouring, and positioning control results. The experimental results prove that the Continuous Motion NCTF controller achieves the same positioning performance as the conventional NCTF controller, and generally achieves better continuous motion control performances than PI-D or conventional NCTF controllers. In 0.25 Hz and 100-nm radius circular motion, the experimental tracking errors for Continuous Motion NCTF were smaller than 10 nm.     

Comments on “enhancement of an efficient liveness-enforcing supervisor for flexible manufacture systems”

Region theory can synthesize maximally permissive supervisors by solving a set of inequalities based on the marking/transition-separation instances (MTSIs). It is infeasible to solve these inequalities for either a sizable net or a small net with a sizable initial marking. Huang et al. [1] propose novel crucial MTSIs to reduce the number of MTSIs. Experimental results show that the proposed control policy is the most efficient algorithm among the closely related approaches. One example shows that it not only reaches all live states but also employs fewer control arcs than that by Li et al. Huang et al. offer no hints on why it employs fewer control arcs. This paper develops theory to explain the physics behind.