scholarly journals Development of Double-Sided Multipoint Press CNC and Operational Technology for Producing Freeform Molds

Buildings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 426
Author(s):  
Jiyeong Yun ◽  
Jongyoung Youn ◽  
Donghoon Lee
Keyword(s):  
Maximum Error ◽  
Numerical Control ◽  
Manual Work ◽  
Rotational Angle ◽  
Concrete Panels ◽  
Significant Step ◽  
Allowable Error ◽  
Production Technologies ◽  
The Difference ◽  
3D Scans

Many studies concerning the precision manufacturing of freeform concrete panels have been conducted, however, this process remains labor intensive taking significant amounts of time and cost. In particular, the precision in the shape of the panels produced tends to be low because of the manual work involved in producing the curves of those panels. This study documents the development of mold production technologies that can be used to produce precise curved surfaces on the upper and lower parts of a mold for freeform concrete panels. A double-sided multipoint press CNC (computer numerical control) produces curved upper and lower surfaces of a mold without the need for manual work, while the operational technology we developed to control this tool enhances the precision of the curves created. The precision of these technologies was verified through experiments. The difference between the shapes designed and those produced were found using 3D scans and quality inspections. Unpredictable errors can occur due to the size of certain curvatures, the elasticity of the silicone plate, and the rotational angle of the joints of the rods supporting the surfaces. To minimize errors, shape compensation was carried out through reverse engineering, leading to a maximum error of 2.887 mm, which is within the allowable error. The results achieved in this study are a significant step toward technologies that will produce increasingly precise freeform concrete panels.

Measuring Surface Uniformity in Chemical Mechanical Polishing

2009 ◽  
Vol 76-78 ◽  
pp. 459-464
Author(s):  
Jae Won Baik ◽  
Chang Wook Kang
Keyword(s):  
Chemical Mechanical Polishing ◽  
Geometric Mean ◽  
Mechanical Polishing ◽  
Wafer Surface ◽  
Semiconductor Wafer ◽  
Statistical Process ◽  
Significant Step ◽  
The Difference ◽  
Thickness Variations ◽  
The Stability

Chemical mechanical polishing (CMP) is a technique used in semiconductor fabrication for planarizing the top surface of an in-process semiconductor wafer. Especially, Post-CMP thickness variations are known to have a severe impact on the stability of downstream processes and ultimately on device yield. Hence understanding how to quantify and characterize this non-uniformity is significant step towards statistical process control to achieve higher quality and enhanced productivity. The main reason is that the non-uniformed interface between the wafer and the machine-pad adversely affects the polishing performance and ultimate surface uniformity. The purpose of this paper is to suggest a new measure that estimates the uniformity of wafer surface considering the difference of the amount of abrasion between the center and the edge. This new measure which is called the Coefficient of Uniformity is defined as the following ratio: Geometric Mean (GM) / Arithmetic Mean (AM). This metric can be evaluated regionally to quantify the non-uniformity on the wafer surface from the center to the edge. Further simulations show that this new measure is insensitive to shift of the wafer center and sensitive to shift of the wafer edge. This trend indicates that this new measure is a very useful to test the non-uniformity of wafer after CMP polishing.

scholarly journals A NOVEL METHOD OF CLOUD AND SHADOW EXTRACTION WITH MULTI-TEMPORAL LANDSAT8 OLI IMAGES

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 1301-1305
Author(s):  
Y. Ni ◽  
G. He ◽  
W. Jiang
Keyword(s):  
Remote Sensing ◽  
Large Change ◽  
Remote Sensing Image ◽  
Image Process ◽  
Actual Application ◽  
Significant Step ◽  
Multi Temporal ◽  
Ground Object ◽  
Novel Method ◽  
The Difference

Cloud and Shadow removal is a significant step in remote sensing image process. As we all know, the ground object coverage type of the same area of the remote sensing image has little change in the short term. But for cloud and shadow coverage areas, the ground object coverage type has large change. Therefore, according to the difference between the two Landsat / OLI images caused by changes in the cover, this paper presents a method of extracting clouds and shadows based on differences in luminance values. This method selects two thresholds for the difference of brightness values, and extracts the clouds and shadows respectively, and validates them with random point method, which can obtain high precision of extracting cloud and shadow and satisfy the actual application needs.

Accuracy of Satellite Land Surface Reflectance Determination

1991 ◽  
Vol 30 (7) ◽  
pp. 960-972 ◽  
Author(s):  
O. Arino ◽  
G. Dedieu ◽  
P. Y. Deschamps
Keyword(s):  
Land Surface ◽  
Surface Albedo ◽  
Maximum Error ◽  
Surface Reflectance ◽  
Relative Uncertainty ◽  
Calibration Uncertainty ◽  
Maximum Bias ◽  
Calibration Accuracy ◽  
The Difference

Abstract An accuracy budget of the surface reflectance determination from Meteosat geostationary satellite data is performed. Error analysis allows identification of three main problems: calibration uncertainty of the Meteosat instrument, atmospheric corrections, and surface effects (spectral and directional). Calibration accuracy is 10%, leading to a 10% relative uncertainty on reflectance. Spectral effects of the surface lead to a maximum bias of 0.01 for a vegetated surface as sensed by Meteosat, while directional effects can lead to a bias of 0.035 between two measurements taken at two different sun zenith and azimuth angles at the same view angle over savannas. The maximum error due to the atmosphere is estimated to be of the order of 0.03 in reflectance for a surface reflectance of 0.40 and 0.01 for, a surface reflectance of 0.10. Validation with in situ measurement is within the expected error over savanna. But the difference is still high over the southwest France site of HAPEX-MOBILHY, certainly due to the joint spectral and directional errors. Comparisons with surface albedo maps from literature show the same spatial and spatial evolutions with a better spatial and temporal determination in our results.

Performance Characteristics of Several Rules for Self-interpretation of Proficiency Testing Data

2005 ◽  
Vol 129 (8) ◽  
pp. 997-1003 ◽  
Author(s):  
R. Neill Carey ◽  
George S. Cembrowski ◽  
Carl C. Garber ◽  
Zohreh Zaki
Keyword(s):  
Proficiency Testing ◽  
Error Detection ◽  
Clinical Laboratory ◽  
Peer Group ◽  
Simulation Techniques ◽  
Allowable Error ◽  
Detection Capabilities ◽  
The Mean ◽  
The Difference

Abstract Context.—Proficiency testing (PT) participants can interpret their results to detect errors even when their performance is acceptable according to the limits set by the PT provider. Objective.—To determine which rules for interpreting PT data provide optimal performance for PT with 5 samples per event. Design.—We used Monte Carlo computer simulation techniques to study the performance of several rules, relating their error detection capabilities to (1) the analytic quality of the method, (2) the probability of failing PT, and (3) the ratio of the peer group SD to the mean intralaboratory SD. Analytic quality is indicated by the ratio of the PT allowable error to the intralaboratory SD. Failure of PT was defined (Clinical Laboratory Improvement Amendments of 1988) as an event when 2 or more results out of 5 exceeded acceptable limits. We investigated rules with limits based on the SD index, the mean SD index, and percentages of allowable error. Results.—No single rule performs optimally across the range of method quality. Conclusions.—We recommend further investigation when PT data cause rejection by any of the following 3 rules: any result exceeds 75% of allowable error, the difference between any 2 results exceeds 4 times the peer group SD, or the mean SD index of all 5 results exceeds 1.5. As method quality increases from marginal to high, false rejections range from 16% to nearly zero, and the probability of detecting a shift equal to 2 times the intralaboratory SD ranges from 94% to 69%.

scholarly journals On a new approach to assessing the energy characteristics of substances

2019 ◽  
Vol 124 ◽  
pp. 01017
Author(s):  
O. S. Sirotkin ◽  
A. M. Pavlova ◽  
R. O. Sirotkin ◽  
A. E. Buntin
Keyword(s):  
Energy Production ◽  
Chemical Interaction ◽  
Heat Of Formation ◽  
Redox Properties ◽  
Chemical Components ◽  
Reaction Products ◽  
Energy Characteristics ◽  
New Approach ◽  
Production Technologies ◽  
The Difference

Within the unified model of chemical bonding and methods of quantitative assessment of components of mixed chemical interaction between the elements in compounds, developed by the authors, a new approach was developed to assess the structural and energy characteristics of substances and fuels. It comprises establishing a correlation between the difference of bonds’ chemical components of reactants and end products. Changes in the chemical bond components affect such characteristics of chemical reactions as the heat of formation of the reaction products, their redox properties, whether reaction is endoor exothermic, as well as the heat of fuel combustion reactions. This approach is an additional reserve for improving the methods for assessing the energy characteristics of fuels and increasing the efficiency of energy production technologies.

Research on Measurement Method of Rotational Angle of Plane Rudder Based on ADXL345 Sensor

2014 ◽  
Vol 556-562 ◽  
pp. 3124-3128
Author(s):  
Quan Fa Yang ◽  
Gui Rong Ye ◽  
Chang You Li
Keyword(s):  
Measurement Method ◽  
Maximum Error ◽  
Angle Measurement ◽  
Coordinate Space ◽  
Acceleration Sensor ◽  
Transformation Theory ◽  
Rotational Angle ◽  
Space Transformation ◽  
Mathematical Expressions ◽  
Inclination Angles

A measurement method based on digital MEMS’ acceleration sensor is proposed. The paper analyzes the working principle of capacitive acceleration sensor. According to the coordinate space transformation theory, a mathematical model of the measurement method was built, and the mathematical expressions of the angle displacement of aircraft rudder was deduced; A measurement system of aircraft tail wing inclined was established using MEMS’ acceleration ADXL345, and taken STM32 as controller. Setting different angles in 3D turntable and aiming at a typical inclination angles, the aircraft tail rotation angle experiment was simulated, and experiment achieved angle measurement arranging from-90°-90°. Experiment results demonstrate that when the inclination is close to the real inclination of aircraft tail wing, the maximum error is 0.277°, less than 0.3°, which meets the requirement of measurement. For aircraft currently being used, the measurement method can achieve the angle measurement of aircraft tail wing rotating effectively.

scholarly journals Accuracy and Repeatability Tests on HoloLens 2 and HTC Vive

2021 ◽  
Author(s):  
Inês Soares ◽  
Ricardo Sousa ◽  
Marcelo Petry ◽  
António Moreira
Keyword(s):  
Virtual Reality ◽  
Augmented Reality ◽  
Industrial Robot ◽  
Ground Truth ◽  
Hand Tracking ◽  
Deep Knowledge ◽  
Significant Step ◽  
Huge Impact ◽  
The Difference ◽  
Accuracy And Repeatability

Augmented and Virtual Reality have been experiencing a rapidly growth in recent years, but there is not still a deep knowledge on their capabilities and where they could be explored. In that sense, this paper presents a study on the accuracy and repeatability of the Microsoft's HoloLens 2 (Augmented Reality device) and HTC Vive (Virtual Reality device) using an OptiTrack system as ground truth. For the HoloLens 2, the method used was hand tracking, while in HTC Vive, the object tracked was the system's hand controller. A series of tests in different scenarios and situations were performed to explore what could influence the measures. The HTC Vive obtained results in the millimetre scale, while the HoloLens 2 revealed not so accurate measures (around 2 centimetres). Although the difference can seem to be considerable, the fact that HoloLens 2 was tracking the user's hand and not an inherit controller made a huge impact. The results were considered a significant step for the on going project of developing a human-robot interface to program by demonstration an industrial robot using Extended Reality, which shows great potential to succeed based on this data.

scholarly journals Evaluation of Analytical Performance of Variant II Turbo HbA1c Analyzer According to Sigma Metrics

2019 ◽  
Vol 38 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Giray Bozkaya ◽  
Nuriye Uzuncan ◽  
Sibel Bilgili ◽  
Ozlem Demirezen
Keyword(s):  
Quality Control ◽  
Control Measures ◽  
Analytical Performance ◽  
Major Constituent ◽  
General Evaluation ◽  
Quality Control Materials ◽  
Allowable Error ◽  
The Difference ◽  
Analytical Variation

Summary Background: Hemoglobin A1c, (HbA1c) which is the major constituent of glycated hemoglobin, has been used in the follow-up of retrospective glycemia for years and in the diagnosis of diabetes mellitus nowadays. Since the analytical performance of HbA1c should be high likewise all laboratory tests, various quality control measures are used. Sigma metrics is one of these measures and it is the combination of bias, precision and total allowable error that ensures a general evaluation of analytical quality. The aim of our study was to evaluate the analytical performance of Bio-Rad’s Variant Turbo II HbA1c analyzer according to sigma metrics. Methods: Sigma levels were calculated using the data obtained from two levels of internal and 12 external quality control materials (Bio-Rad) of Variant II Turbo HbA1c analyzer according to s= (TEa% - Bias%) / CV% formula. Results: The mean sigma levels for low and high quality control materials were found to be 3.0 and 4.1, respectively. Conclusions: The annual mean analytical performance of Variant II Turbo HbA1c analyzer was found to be acceptable according to sigma metrics. In order to be sure of the difference in HbA1c results indicating the success or failure in treatment but not arise from analytical variation, it is thought that more stringent quality control measures should be applied to reach higher sigma levels.

Studies on Sterility and Prenatal Mortality in Wild Rabbits

1947 ◽  
Vol 23 (3-4) ◽  
pp. 312-331
Author(s):  
PATRICIA ALLEN ◽  
F. W. ROGERS BRAMBELL ◽  
IVOR H. MILLS
Keyword(s):  
Experimental Error ◽  
Total Error ◽  
Maximum Error ◽  
Corpora Lutea ◽  
Significant Relation ◽  
Technical Problems ◽  
Before And After ◽  
Implantation Sites ◽  
The Mean ◽  
The Difference

1. The technical problems underlying the estimation and analysis of the total prenatal mortality in a mammal are reviewed, with particular reference to the rabbit. 2. The material consisted of 7137 wild rabbits, of which 5089 were females. These comprise eleven series, according to the year, locality and treatment, particulars of which are given. 3. The experimental error in counts of corpora lutea was investigated and the technique critically examined. The changes in size of the corpus luteum during pregnancy were measured and a growth curve constructed. The mean number of corpora lutea in a litter, as determined from macroscopic counts, was found to be significantly lower at the beginning and end of pregnancy than in the middle. If this is due to omissions in the counts it represents a maximum error of 6.8% of corpora lutea. Microscopic counts of the corpora lutea in freehand sections of 180 pairs of ovaries of pregnant animals were made as a control. These revealed a total error in the original counts of 6.4% of the corpora lutea, affecting 25.6% of the litters, but this was distributed evenly throughout gestation. 4. Corpora lutea atretica formed from unruptured follicles are present in 16% of the pairs of ovaries, and comprise less than 2% of all corpora lutea. They are formed at the same time as the normal corpora lutea, and there is no evidence that any are formed subsequently during pregnancy in the rabbit. 5. It is estimated that 0.23% of the follicles which ovulate produce two embryos through the liberation of two ova. 6. Transperitoneal migration of 0.37% of ova, affecting 2% of the litters, was found to occur. The probability of migration either from left to right or from right to left appeared to be equal. 7. Significant changes in the mean number of implantation sites in the uteri counted at successive stages of pregnancy were observed, and particularly a decline at the end of gestation. They are of the same order as those in the mean number of corpora lutea, which they will tend to compensate so far as estimates of loss of ova before implantation are concerned. It is by no means clear that these are due to experimental error in the counts. 8. Estimates of the loss of embryos before implantation are based on the difference between the number of corpora lutea in the ovaries and of implantation sites in the uteri, and estimates of the loss after implantation on the difference between the number of implantation sites and of developing embryos. No significant relation has been found between the loss before and after implantation respectively, and it is concluded that the loss suffered after implantation is distributed independently of that which occurs before implantation.

How to certify reference materials: by voting or by exact weights

2021 ◽  
Vol 04 (1) ◽  
pp. 20-26
Author(s):  
A. B. Kopiltsova ◽  
◽  
B. P. Tarasov ◽  
U. A. Kopiltsov ◽  
◽  
...  
Keyword(s):  
Reference Materials ◽  
Petroleum Products ◽  
Heavy Oils ◽  
Accuracy Control ◽  
Standard Methods ◽  
Main Application ◽  
True Value ◽  
Interlaboratory Studies ◽  
Production Technologies ◽  
The Difference

The problems of using reference materials (RM) of oil and petroleum products humidity is discussed for different programs of certification: according to accuracy of the preparation procedure (RM-PP), according to the results of the interlaboratory studies (RM-INTERLAB) and using reference methods (RM-RM). Similar NIST samples (SRM 2271 and 272) were used for comparison. The problem of using CO-INTERLAB for control the accuracy of standard methods is the absence of the true value, this task is not even raised. "Accuracy control" has a different emphasis in this situation: RM-INTERLAB allow to select, "voting by majority" among the general population of the laboratory and cut the others. Therefore, their main application is qualification tasks. This approach is basically incorrect for analyzers. In the case of RM-PP and RM-RM, the main problem is the difference in the composition of real samples and ideal matrices of RM’s. Their main application is the control the accuracy of the analyzers in the absence of interfering influences. The "cheap" RM’s production technologies do not allow the omprehensive control of the real oil samples. The complication of oil technologies and the use of heavy oils in refining could provide the progress in RM’s.

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