scholarly journals New proposed method for traceability dissemination of capacitance measurements

2021 ◽  
Vol 11 (3) ◽  
pp. 1969
Author(s):  
Heba A. M. Hamed ◽  
A. Eliwa Gad ◽  
M. Helmy A. Raouf
Keyword(s):  
Measurement Method ◽  
New Method ◽  
Substitution Method ◽  
Capacitance Measurements ◽  
Acceptable Accuracy ◽  
Capacitance Bridge ◽  
Ultra Precision ◽  
Relative Differences

Capacitance measurements at the National Institute of Standards (NIS), Egypt, are traceable to the Bureau International des Poids et Mesures (BIPM). It calibrates the main NIS standard capacitors, AH11A. In this paper, traceability of the BIPM capacitance measurements could be used to evaluate a new accurate measurement method through an Ultra-Precision Capacitance Bridge. The new method is carefully described by introducing some necessary equations and a demonstrating chart. Verification of this new method has been realized by comparing its results for the 10 pF and 100 pF capacitance standards with the results obtained by the conventional substitution method at 1 kHz and 1.592 kHz. The relative differences between the two methods are about 0.3 µF/F, which reflect the accuracy of the new measurement method. For higher capacitance ranges, the new measurement method has been applied for the capacitance measurements up to 1 μF at 1 kHz. The relative differences between the two methods are in the range of 5.5 µF/F on the average which proves the acceptable accuracy and the reliability of the new method to be used.

Model and Measurement Method of Optical Nonlinearities Caused by the Heterodyne and Homodyne Interference Terms in the Heterodyne Interferometer

2014 ◽  
Vol 613 ◽  
pp. 58-63
Author(s):  
Hai Jin Fu ◽  
Jiu Bin Tan ◽  
Peng Cheng Hu ◽  
Zhi Gang Fan
Keyword(s):  
Measurement Method ◽  
Laser Interferometer ◽  
Optical Nonlinearity ◽  
Laser Source ◽  
Optical Nonlinearities ◽  
Laser Polarization ◽  
Heterodyne Interferometer ◽  
Optical Mixing ◽  
Ultra Precision ◽  
Heterodyne Laser Interferometer

The heterodyne laser interferometer is widely applied in ultra-precision displacement measurement, but its accuracy is seriously restricted by the optical nonlinearity which arises from the optical mixing in the reference and measurement arms. In an ideal heterodyne laser interferometer, the beam from the laser source consists of two orthogonally linear-polarized components with slightly different optical frequencies and the two components can be completely separated by the polarizing optics, one traverses in the reference arm, the other traverses in the measurement arm, both of them are in the form of a pure optical frequency. However, in a real heterodyne laser interferometer, due to the imperfect laser polarization, the optics defect and the misalignment, the two components of the laser beam cant be perfectly separated, therefore both of the reference arm and the measurement arm contain a portion of the two laser components, which leads to an optical mixing in the two arms of the heterodyne interferometer and causes the cyclic nonlinearity of several to tens of nanometers.

Cross Calibration by FFT Equalization

1997 ◽  
Vol 119 (2) ◽  
pp. 236-242 ◽  
Author(s):  
K. Peleg
Keyword(s):  
Measurement Method ◽  
Functional Relationship ◽  
Measurement Methods ◽  
New Method ◽  
Measurement Systems ◽  
True Value ◽  
Calibration Problem ◽  
Regression Techniques ◽  
The Cross ◽  
Cross Calibration

The classical calibration problem is primarily concerned with comparing an approximate measurement method with a very precise one. Frequently, both measurement methods are very noisy, so we cannot regard either method as giving the true value of the quantity being measured. Sometimes, it is desired to replace a destructive or slow measurement method, by a noninvasive, faster or less expensive one. The simplest solution is to cross calibrate one measurement method in terms of the other. The common practice is to use regression models, as cross calibration formulas. However, such models do not attempt to discriminate between the clutter and the true functional relationship between the cross calibrated measurement methods. A new approach is proposed, based on minimizing the sum of squares of the differences between the absolute values of the Fast Fourier Transform (FFT) series, derived from the readings of the cross calibrated measurement methods. The line taken is illustrated by cross calibration examples of simulated linear and nonlinear measurement systems, with various levels of additive noise, wherein the new method is compared to the classical regression techniques. It is shown, that the new method can discover better the true functional relationship between two measurement systems, which is occluded by the noise.

An Ultra-Precision on-Machine Measurement Method of Aspheric Surface

2012 ◽  
Vol 49 (7) ◽  
pp. 071203
Author(s):  
陈逢军 Chen Fengjun ◽  
尹韶辉 Yin Shaohui ◽  
余剑武 Yu Jianwu ◽  
王宇 Wang Yu ◽  
朱勇建 Zhu Yongjian
Keyword(s):  
Measurement Method ◽  
Aspheric Surface ◽  
Ultra Precision

Odour emission capacity of wastewaters - standardization of measurement method and application

1998 ◽  
Vol 38 (3) ◽  
pp. 61-69 ◽  
Author(s):  
Franz-Bernd Frechen ◽  
Wulf Köster
Keyword(s):  
Wastewater Treatment ◽  
Liquid Phase ◽  
Case Studies ◽  
Mass Flow ◽  
Measurement Method ◽  
Wastewater Treatment Plants ◽  
Ambient Air ◽  
New Method ◽  
Sewer Systems ◽  
Emission Capacity

Odorous emissions from sewer systems and wastewater treatment plants can cause serious annoyance in the vicinity. Odorants which are present in a liquid phase are emitted into ambient air at the liquid-gaseous interface. The amount and the variation of emitted mass flow of odorants is significantly influenced by the amount of odorants which are present in the liquid. Up to now, however, no measurement method was available to describe this parameter, which can be called “Odorants Emission Capacity”. The paper describes a standardized method of determining the “Odorants Emission Capacity” and shows results and consequences from several case studies where this new method was applied.

Research on Tooth Profile Deviations Measurement Method Based on the Optical Image Measuring Instrument

2013 ◽  
Vol 712-715 ◽  
pp. 1979-1982 ◽  
Author(s):  
Qing Hai Wang ◽  
Feng Xia Zhao
Keyword(s):  
Mathematical Models ◽  
Measurement Method ◽  
Tooth Profile ◽  
Optical Image ◽  
New Method ◽  
Profile Measurement ◽  
Measuring Instrument ◽  
Profile Deviation ◽  
Form Deviation ◽  
Fitting Error

To resolve the problems of small module gear measurement with traditional methods, a new method for measuring the tooth profile deviations of small module gear using the optical image measuring instrument is put forward. According to the ISO 1328-1, the mathematical models of total profile deviation, profile form deviation and profile slope deviation are proposed. The involute profile measurement schemes are given. The results show that tooth profile coordinate values of small module gear can be measured automatically and effectively with the optical image measuring instrument, and the provided method has higher precision of getting measuring points and less fitting error of tooth profile.

scholarly journals New Measurement Method and Uncertainty Estimation for Plate Dimensions and Surface Quality

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Salah H. R. Ali ◽  
Jariya Buajarern
Keyword(s):  
Surface Quality ◽  
Mass Production ◽  
Traditional Method ◽  
Edge Crack ◽  
Measurement Method ◽  
Large Scale ◽  
Production Control ◽  
Uncertainty Estimation ◽  
New Method

Dimensional and surface quality for plate production control is facing difficult engineering challenges. One of these challenges is that plates in large-scale mass production contain geometric uneven surfaces. There is a traditional measurement method used to assess the tile plate dimensions and surface quality based on standard specifications: ISO-10545-2: 1995, EOS-3168-2: 2007, and TIS 2398-2: 2008. A proposed measurement method of the dimensions and surface quality for ceramic oblong large-scale tile plate has been developed compared to the traditional method. The strategy of new method is based on CMM straightness measurement strategy instead of the centre point in the traditional method. Expanded uncertainties budgets in the measurements of each method have been estimated in detail. The capability of accurate estimations of real actual results for centre of curvature (CC), centre of edge (CE), warpage (W), and edge crack defects parameters has been achieved according to standards. Moreover, the obtained results not only showed better accurate new method but also improved the quality of plate products significantly.

scholarly journals A Digital Heterodyne 2-150 kHz Measurement Method

2021 ◽  
Author(s):  
Paul Wright ◽  
Deborah Ritzmann
Keyword(s):  
Measurement Method ◽  
Power Grid ◽  
New Method ◽  
Digital Method ◽  
Frequency Range ◽  
Multi Resolution Analysis ◽  
Resolution Analysis ◽  
Conducted Emissions

This paper describes a new method for measurements of signals in the 2–150 kHz frequency range, as required to support the regulation of conducted emissions on the power grid. The digital method is based on heterodyning, decimation and multi resolution analysis.<div><br></div>

scholarly journals On-machine Measurement and Uncertainty Analysis for Semicircular Narrow Neck Thickness based on Ultra-precision Machine Tool

2021 ◽  
Author(s):  
Xin Jin ◽  
Ruilin Gao ◽  
Chaojiang Li ◽  
Zhong peng Zheng ◽  
zhen Zuo
Keyword(s):  
Measurement Method ◽  
Dimensional Accuracy ◽  
Position Measurement ◽  
Measuring Device ◽  
Flexible Joint ◽  
Accuracy Requirement ◽  
Narrow Neck ◽  
Precision Machine ◽  
Measuring Accuracy ◽  
Ultra Precision

Abstract As flexible joint is a typical low-rigidity micro part, which have four narrow neck structures evenly distributed around its central axis, it is necessary to strictly control the dimensional accuracy of the narrow necks to improve the consistency of stiffness. However, the radius of the arc of the narrow necks is less than 2mm, and the thickness of thinnest part of the necks formed by two adjacent arcs is only tens of microns, which also has sub-micron accuracy requirement. These cross-scale dimensional characteristics and accuracy requirements give rise to extremely difficulty on the measuring process. In this paper, an on-machine measurement method for the semicircular narrow necks was presented and a measuring device was developed based on the comparative principle by making full use of the high linearity characteristic in the small measuring range of the sensor probes. Meanwhile, the on-machine measurement process based on ultra-precision machine tools was also introduced in details. The experiments results show that the uncertainty of the measurement method proposed is less than 0.2µm, and the repeatability is less than 0.1μm, which meet the measuring requirement of flexible joint. Furthermore, the effect of probe position, measurement force, environmental factor and the accuracy of the sensor on total measuring accuracy was analyzed, which could provide further evidences to improve the measuring accuracy. of micro-scale hybrid surface texture.

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