A Study on Fast Geometric Form Measurement of High Precision Balls

2014 ◽  
Vol 1017 ◽  
pp. 669-674
Author(s):  
Hui Zong Lu ◽  
Zhi Wei Wang ◽  
Qian Fa Deng ◽  
Bing Hai Lv ◽  
Fen Fen Zhou ◽  
...  
Keyword(s):  
High Precision ◽  
Online Application ◽  
Diameter Variation ◽  
Measurement Results ◽  
Data Points ◽  
Ball Diameter ◽  
Multiple Measurements ◽  
Set Up ◽  
Dual Probe ◽  
Roundness Measurement

A dual probe non-contact ball roundness measurement method is presented in this paper. With two probes aligned in opposite directions, the direct measurement of diameter variation can be obtained. The relationships between diameter variation and out of roundness of a precision ball are discussed. Attempts of error separation using multiple measurements are carried out and the eccentricity of ball and spindle axis is measured. Measurement results indicated that other than the spindle radial run out, which is synchronous in nature, there also exists high frequency non-synchronous variations. Such non-synchronous errors can be effectively eliminated with the dual probe arrangement for diameter variation measurement. The measurement results showed that such set up is capable of measuring high precision balls for diameter variation and out of roundness with uncertainty of less than 10nm. Single measurement can be completed in 10 seconds with over 10,000 data points. Faster measurement is possible with improved air bearing spindle. The method is suitable for online application of precision ball diameter variation and out of roundness measurement.

Uncertainty Calculation of Roundness by Automatic Differentiation

2010 ◽  
Vol 437 ◽  
pp. 217-221
Author(s):  
Jia Chun Lin ◽  
Michael Paul Krystek ◽  
Zhao Yao Shi
Keyword(s):  
Measurement Uncertainty ◽  
Automatic Differentiation ◽  
Uncertainty In Measurement ◽  
Uncertainty Calculation ◽  
Measurement Results ◽  
Coordinate Metrology ◽  
Data Points ◽  
Roundness Deviation ◽  
Expression Of Uncertainty ◽  
Roundness Measurement

According to the Guide to the Expression of Uncertainty in Measurement (GUM), all measurement results must have a stated uncertainty associated to them. But in most cases of roundness measurement either no uncertainty value is given, or the calculation is not based on the model of the respective association criterion for the geometrical feature, because no suitable measurement uncertainty calculation procedure does exist. For the case of roundness measurement in coordinate metrology, this paper will suggest algorithms for the calculation of the measurement uncertainty of the roundness deviation based on the two mainly used association criteria LSC and MZC. The calculation of the sensitivity coefficients for the uncertainty calculation can be done by automatic differentiation, in order to avoid introducing additional errors by the traditional difference quotient approximations. The proposed methods are exact and need as input data only the measured co-ordinates of the data points and their associated uncertainties.

State special primary acceleration measurement standard for gravimetry GET 190-2019

2020 ◽  
pp. 3-8
Author(s):  
L.F. Vitushkin ◽  
F.F. Karpeshin ◽  
E.P. Krivtsov ◽  
P.P. Krolitsky ◽  
V.V. Nalivaev ◽  
...  
Keyword(s):  
High Precision ◽  
Free Fall ◽  
Measurement Range ◽  
Measurement Standard ◽  
Acceleration Measurement ◽  
Measurement Systems ◽  
Free Fall Acceleration ◽  
Investigation Methods ◽  
Measurement Results ◽  
Upper Level

The State special primary acceleration measurement standard for gravimetry (GET 190-2019), its composition, principle of operation and basic metrological characteristics are presented. This standard is on the upper level of reference for free-fall acceleration measurements. Its accuracy and reliability were improved as a result of optimisation of the adjustment procedures for measurement systems and its integration within the upgraded systems, units and modern hardware components. A special attention was given to adjusting the corrections applied to measurement results with respect to procedural, physical and technical limitations. The used investigation methods made it possibled to confirm the measurement range of GET 190-2019 and to determine the contributions of main sources of errors and the total value of these errors. The measurement characteristics and GET 90-2019 were confirmed by the results obtained from measurements of the absolute value of the free fall acceleration at the gravimetrical site “Lomonosov-1” and by their collation with the data of different dates obtained from measurements by high-precision foreign and domestic gravimeters. Topicality of such measurements ensues from the requirements to handle the applied problems that need data on parameters of the Earth gravitational field, to be adequately faced. Geophysics and navigation are the main fields of application for high-precision measurements in this field.

scholarly journals Influence of a Thermal Pad on Selected Parameters of Power LEDs

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3732
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak ◽  
Tomasz Torzewicz ◽  
Marcin Janicki
Keyword(s):  
Optical Properties ◽  
Thermal Resistance ◽  
Optical Power ◽  
Junction Temperature ◽  
Operating Parameters ◽  
Cold Plate ◽  
Optical Efficiency ◽  
Forward Current ◽  
Measurement Results ◽  
Set Up

This paper is devoted to the analysis of the influence of thermal pads on electric, optical, and thermal parameters of power LEDs. Measurements of parameters, such as thermal resistance, optical efficiency, and optical power, were performed for selected types of power LEDs operating with a thermal pad and without it at different values of the diode forward current and temperature of the cold plate. First, the measurement set-up used in the paper is described in detail. Then, the measurement results obtained for both considered manners of power LED assembly are compared. Some characteristics that illustrate the influence of forward current and temperature of the cold plate on electric, thermal, and optical properties of the tested devices are presented and discussed. It is shown that the use of the thermal pad makes it possible to achieve more advantageous values of operating parameters of the considered semiconductor devices at lower values of their junction temperature, which guarantees an increase in their lifetime.

Statistical Analysis of Avian Reproduction Studies

2021 ◽  
Author(s):  
John W Green ◽  
Manousos Foudoulakis ◽  
Timothy Fredricks ◽  
Tiffany Carro ◽  
Jonathan Maul ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Study Design ◽  
Model Averaging ◽  
Study Data ◽  
Design Elements ◽  
Avian Reproduction ◽  
Reproduction Study ◽  
Data Points ◽  
Set Up ◽  
Regulatory Risk Assessment

Abstract Avian reproduction studies for regulatory risk assessment are undergoing review by regulatory authorities, often leading to requests for statistical re-analysis of older studies using newer methods, sometimes with older study data that do not support these newer methods. We propose detailed statistical protocols with updated statistical methodology for use with both new and older studies and recommend improvements in experimental study design to set-up future studies for robust statistical analyses. There is increased regulatory and industry attention to the potential use of benchmark dose (BMD) methodology to derive the point of departure in avian reproduction studies, to be used as the endpoint in regulatory risk assessment. We present benefits and limitations of this BMD approach for older studies being re-evaluated and for new studies designed for with BMD analysis anticipated. Model averaging is recommended as preferable to model selection for BMD analysis. Even for a new study following the modified experimental design analyses with BMD methodology will only be possible for a restricted set of response variables. The judicious use of historical control data, identification of outlier data points, increased use of distributions more consistent with the nature of the data collected as opposed to forcing normality-based methods, and trend-based hypothesis tests are shown to be effective for many studies, but limitations on their applicability are also recognized and explained. Updated statistical methodologies are illustrated with case studies conducted under existing regulatory guidelines that have been submitted for product registrations. Through the adoption of improved avian reproduction study design elements combined with the suggested revised statistical methodologies the conduct, analyses, and utility of avian reproduction studies for avian risk assessments can be improved.

scholarly journals Exploring the relation between aerosol optical depth and PM<sub>2.5</sub> at Cabauw, the Netherlands

2008 ◽  
Vol 8 (5) ◽  
pp. 17939-17986 ◽  
Author(s):  
M. Schaap ◽  
A. Apituley ◽  
R. M. A. Timmermans ◽  
R. B. A. Koelemeijer ◽  
G. de Leeuw
Keyword(s):  
The Netherlands ◽  
Ground Level ◽  
Weather Conditions ◽  
Fair Weather ◽  
Modis Aod ◽  
Data Points ◽  
Set Up ◽  
The Relationship ◽  
Lidar Observations ◽  
Pm2.5 Concentration

Abstract. To acquire daily estimates of PM2.5 distributions based on satellite data one depends critically on an established relation between AOD and ground level PM2.5. In this study we aimed to experimentally establish the AOD-PM2.5 relationship for the Netherlands. For that purpose an experiment was set-up at the AERONET site Cabauw. The average PM2.5 concentration during this ten month study was 18 μg/m3, which confirms that the Netherlands are characterised by a high PM burden. A first inspection of the AERONET level 1.5 (L1.5) AOD and PM2.5 data at Cabauw showed a low correlation between the two properties. However, after screening for cloud contamination in the AERONET L1.5 data, the correlation improved substantially. When also constraining the dataset to data points acquired around noon, the correlation between AOD and PM2.5 amounted to R2=0.6 for situations with fair weather. This indicates that AOD data contain information about the temporal evolution of PM2.5. We had used LIDAR observations to detect residual cloud contamination in the AERONET L1.5 data. Comparison of our cloud-screed L1.5 with AERONET L2 data that became available near the end of the study showed favorable agreement. The final relation found for Cabauw is PM2.5=124.5*AOD–0.34 (with PM2.5 in μg/m3) and is valid for fair weather conditions. The relationship determined between MODIS AOD and ground level PM2.5 at Cabauw is very similar to that based on the much larger dataset from the sun photometer data, after correcting for a systematic overestimation of the MODIS data of 0.05. We applied the relationship to a MODIS composite map to assess the PM2.5 distribution over the Netherlands. Spatial dependent systematic errors in the MODIS AOD, probably related to variability in surface reflectance, hamper a meaningful analysis of the spatial distribution of PM2.5 using AOD data at the scale of the Netherlands.

scholarly journals Making roundness measurement applications and control systems on the Roundness Tester Machine

2019 ◽  
Vol 63 (3) ◽  
pp. 17-21
Author(s):  
Dodi Sofyan Arief ◽  
◽  
Eko Jadmiko ◽  
Adhy Prayitno ◽  
Muftil Badri ◽  
...  
Keyword(s):  
Control Systems ◽  
Measurement Data ◽  
Rotating Speed ◽  
Center Point ◽  
Global Quality ◽  
Measurement Results ◽  
Roundness Deviation ◽  
And Control ◽  
Dial Indicator ◽  
Roundness Measurement

Dial indicator is a comparison device usually used in industrial activities, especially in production. To make measurements at this time must be supported by technology that can facilitate operators when using it and when analyzing measurement results. Involving the programme and microcontroller are a solution to developing in roundness measurement, and then the results can be more accurate or thorough between the readable values read from the measuring instrument with the actual value of varying the amount of data. Roundness application is a program that can input measurement data automatically and can do calculations directly. Then, it can display a reference circle, a table that calculates the values of X, Y, R, X’, Y’, R’, Roundness Deviation, Run out Concentricity or a shift in the center point and also the center point shift or Theta. In measuring roundness, the test object is used the Standard Mandrel which has been certified by PT. Global Quality Indonesia, by determining three points or positions, namely in the first position the amount of data is 180, in the second position the amount of data is 90 and in the third position, the amount of data is 60 with a rotating speed of 15 mm/s. The results of the reference circle can be seen in each calculation in each position, in the second position the roundness deviation values are approaching of the Mandrel.

scholarly journals Simulation of High Precision Process Control for Set-up Dominant Processes

Procedia CIRP ◽  
2013 ◽  
Vol 11 ◽  
pp. 379-384 ◽  
Author(s):  
Steven Cox ◽  
John Garside ◽  
Apostolos Kotsialos
Keyword(s):  
Process Control ◽  
High Precision ◽  
Set Up

scholarly journals High-Precision Distance Measurement with an unmanned, Moving Target

1986 ◽  
Vol 8 ◽  
pp. 93-95
Author(s):  
H. Ito ◽  
K. Schroff ◽  
Hans-jörg Frei
Keyword(s):  
Sea Ice ◽  
High Precision ◽  
Distance Measurement ◽  
Moving Object ◽  
Measuring Instruments ◽  
Moving Target ◽  
Personnel Cost ◽  
Greenland Sea ◽  
Single Station ◽  
Set Up

A device was developed, which rotates a marker for the distance measurement in the desired direction, without an operator at the spot. This is also possible with a moving object, on which the marker is set up. The device, together with adequate distance-measuring instruments, yields a precise distance measurement by a single observer at a single station. Examples of measurements using it during sea-ice studies in the Greenland Sea are described. It is shown that the application of the instrument provides a satisfactory basis for precise glacier surveying with limited personnel, cost, and time.

scholarly journals High Precision Stellar Photometry by CCDs. II

1995 ◽  
Vol 167 ◽  
pp. 175-185
Author(s):  
Michael S. Bessell
Keyword(s):  
High Precision ◽  
Ccd Photometry ◽  
Stellar Photometry ◽  
Set Up ◽  
Good Range

CCD photometry is capable of high internal precision, however there are several important requirements necessary to attain high precision in standardized photometry. Firstly, the CCD passbands must match as closely as possible the standard passbands; secondly, new faint standards must be set up in several declination zones and thirdly, for convenience a sufficient number of standards covering a good range in color should be obtained on a single CCD frame so that several different frames should suffice for standardization. Landolt has taken the first steps in defining several such fields. The small systematic differences between different UBVRI systems have been examined and transformations can be applied to the photometry of Landolt and Bessell to place it on the Cape — SAAO system.

scholarly journals Modernization of Chinese Photoelectric Astrolabes and Improvement of Optical Reference System

1990 ◽  
Vol 141 ◽  
pp. 519-520
Author(s):  
Li Dong-Ming ◽  
Wang Hong-Qi ◽  
Zhao Gang ◽  
Wang Ze-Zhi ◽  
Wang Rui
Keyword(s):  
High Precision ◽  
Reference System ◽  
Optical Reference ◽  
Set Up

The features of the astrolabe are that:(1) a span of 6 hour of R.A. of star positions can be tied in a group of observation of 2 hours, all-night observation can cover more than half of the sky, and(2) the declination system can be set up with high precision without the need of a precise circle (Li 1987).

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