tolerance limits
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ACTA IMEKO ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 54
Author(s):  
Oleksandr Vasilevskyi ◽  
Maryna Koval ◽  
Svetlana Kravets

<p>A technique is proposed for estimating the probability of the possible appearance of defective products or the inconsistency of the production service on the basis of indexes of suitability and reproducibility of the production process.</p><p>The index of reproduction is recommended to be calculated on the basis of the standard deviation, which can be established by the average span of the control map and the limits of the tolerance field. At the same time, the production process must necessarily be in a state of statistical controllability. The suitability index cannot be calculated on the basis of the control card characteristics, but it is evaluated solely on the basis of the total of the standard deviation, which is calculated by the Bessel formula and the tolerance limits. The production process does not need to be statistically controllable. Conclusions on the suitability or insufficiency of the products (production services) are based on the value of the indexes of reproduction and suitability, which can take values less than or greater than one. On the basis of these indexes of obtained values, the probability of production appearance or characteristics of the production process, that does not match the established requirements, is established.</p>


2021 ◽  
Vol 11 (24) ◽  
pp. 11657
Author(s):  
Laura Bernes Martinez ◽  
Daniele Garcovich ◽  
Alfonso Alvarado Lorenzo ◽  
Angel Zhou Wu ◽  
Riccardo Aiuto ◽  
...  

Background: The precision of bracket manufacturing is fundamental to ensure the correct expression of the inbuilt information. The objective of this study was to determine the actual tip and torque values of a pool of stainless steel brackets, pre-adjusted according to the MBT prescription values, and to compare these actual values with those stated by the manufacturers in order to test their compliance with the tolerance limits reported in the ISO 27020:2019 Methods: A sample of 360 stainless steel brackets, from 12 different providers, were evaluated. All brackets had a nominal slot size of 0.022 in., belonged to the upper right central incisor, and were manufactured with the metal injection molding technique (MIM). For each provider, three different batches of the same bracket series were tested. A single-blind design was used for bracket coding. Results: Only five systems displayed torque mean values that matched the declared values (p > 0.05). Only one system did not respect the tolerance limits established in the ISO 27020:2019 norm. The tip values were different from those declared in seven of the assessed systems; however, none exceeded the tolerance limits. The inter-batch variability in most cases was not statistically significant. Conclusions: In most of the assessed systems, there can be a difference between the actual and the declared torque values, while tip information is usually accurately incorporated into the bracket slot. Lack of precision in the manufacturing process can reduce the efficacy of the appliance and force the clinician to compensate for dimensional inaccuracy through wire bending.


2021 ◽  
pp. 017084062110586
Author(s):  
Karolina Mikołajewska-Zając ◽  
Attila Márton ◽  
Mike Zundel

Digital platforms radically alter socio-economic and organizational patterns. In an ecological sense, they enable the rapid extension of tolerance limits by digitally scaling variables such as the availability of accommodation or labour. However, such maximization of specific variables in a complex ecology bears the danger of pathological runaway patterns. In our paper we draw on the work of Gregory Bateson to outline an analytical approach for the study of digital platforms as ecological phenomena, focussing on the effects of digitalization on the context in which platforms operate. To study such meta-patterns, we elaborate three interrelated concepts: stress, adaptation and budgets of flexibility. We exemplify these ideas through a longitudinal study of the early digital platform Couchsurfing and develop implications for our understanding of technology and organization.


2021 ◽  
pp. 103151
Author(s):  
Madalena Missionário ◽  
Joana Filipa Fernandes ◽  
Margarida Travesso ◽  
Eduardo Freitas ◽  
Ricardo Calado ◽  
...  

2021 ◽  
Vol 869 (1) ◽  
pp. 012014
Author(s):  
C Octavina ◽  
M Ulfah ◽  
N Nurfadillah ◽  
S Agustina ◽  
J Niwatana ◽  
...  

Abstract This study aimed to determine the population structure of Lingula sp. in the Aceh northern shore. This research uses purposive sampling method where the sampling locations at Ujong Pancu beach, Kuala Cangkoi beach, Syiah Kuala beach and Alue Naga beach. Sampling was carried out using a quadratic transect (1x1 m) with three stations at each location. The results showed that there is one type of Brachiopods, namely the genus Lingula (Bruguière 1791), species Lingula anatina Lamarck, 1801 which are scattered on the north coast of Aceh. Overall, the abundance of L. anatina was quite high at each location, especially at Kuala Cangkoi beach (2.43 ind/m2), while the lowest abundance was found at Ujong Pancu beach (1,11 ind/m2). In addition, it was also found that L. anatina had a similarity distribution on the Aceh northern shore. The existence of L. anatina on the Aceh northern shore is very dependent on good environmental conditions, in general, the quality of the waters of Aceh northern shore is still within the tolerance limits of these biota. Therefore, population structure of L. anatina is stable, so that this biota resource must continue to be considered and managed properly.


2021 ◽  
Vol 9 (6) ◽  
pp. 103-108
Author(s):  
Mohammad Ashaf-Ud-Doulah ◽  
Md. Shariful Islam ◽  
Nafia Binte Ryhan ◽  
Shaheed Nasrullah Al Mamun ◽  
Kazi Atiah Taiyebi ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7092
Author(s):  
Hany Abdel-Khalik ◽  
Dongli Huang ◽  
Ugur Mertyurek ◽  
William Marshall ◽  
William Wieselquist

To establish confidence in the results of computerized physics models, a key regulatory requirement is to develop a scientifically defendable process. The methods employed for confidence, characterization, and consolidation, or C3, are statistically involved and are often accessible only to avid statisticians. This manuscript serves as a pedagogical presentation of the C3 process to all stakeholders—including researchers, industrial practitioners, and regulators—to impart an intuitive understanding of the key concepts and mathematical methods entailed by C3. The primary focus is on calculation of tolerance limits, which is the overall goal of the C3 process. Tolerance limits encode the confidence in the calculation results as communicated to the regulator. Understanding the C3 process is especially critical today, as the nuclear industry is considering more innovative ways to assess new technologies, including new reactor and fuel concepts, via an integrated approach that optimally combines modeling and simulation and minimal targeted validation experiments. This manuscript employs intuitive, analytical, numerical, and visual representations to explain how tolerance limits may be calculated for a wide range of configurations, and it also describes how their values may be interpreted. Various verification tests have been developed to test the calculated tolerance limits and to help delineate their values. The manuscript demonstrates the calculation of tolerance limits for TSURFER, a computer code developed by the Oak Ridge National Laboratory for criticality safety applications. The goal is to evaluate the tolerance limit for TSURFER-determined criticality biases to support the determination of upper, subcritical limits for regulatory purposes.


2021 ◽  
Vol 4 (2) ◽  
pp. 119-126
Author(s):  
Made Agung Raharja ◽  
I Dewa Made Bayu Atmaja Darmawan

Cultural traditions from the life of the Balinese people have given birth to various types of things, ranging from dances, traditional clothing, music and traditional musical instruments. One of the gamelan instruments in Bali is Gerantang. Everyone does not have the ability to adjust the tone of the greantang blades, so that the process of making the bushes cannot be done by just anyone. In the field of sound / audio processing, there is a method called speech synthesis. One method that can be used in implementing music or tone synthesis is the Double Frequency Modulation (DFM) method. Tests that have been carried out in the synthesis process of gamelan grantang sound using the DFM method have been successfully carried out with a total of 55 test tone data and from 11 basic tones and frequencies of several synthetic sound experiments in the output column and in the results column show 10 output results are within tolerance limits frequency and 1 (one) tone out of tolerance. It was found that 10 tones that have been synthesized produce tones that have frequencies within the frequency tolerance limit with an accuracy of 90.9%


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6318
Author(s):  
Dan Gabriel Cacuci

This work aims at underscoring the need for the accurate quantification of the sensitivities (i.e., functional derivatives) of the results (a.k.a. “responses”) produced by large-scale computational models with respect to the models’ parameters, which are seldom known perfectly in practice. The large impact that can arise from sensitivities of order higher than first has been highlighted by the results of a third-order sensitivity and uncertainty analysis of an OECD/NEA reactor physics benchmark, which will be briefly reviewed in this work to underscore that neglecting the higher-order sensitivities causes substantial errors in predicting the expectation and variance of model responses. The importance of accurately computing the higher-order sensitivities is further highlighted in this work by presenting a text-book analytical example from the field of neutron transport, which impresses the need for the accurate quantification of higher-order response sensitivities by demonstrating that their neglect would lead to substantial errors in predicting the moments (expectation, variance, skewness, kurtosis) of the model response’s distribution in the phase space of model parameters. The incorporation of response sensitivities in methodologies for uncertainty quantification, data adjustment and predictive modeling currently available for nuclear engineering systems is also reviewed. The fundamental conclusion highlighted by this work is that confidence intervals and tolerance limits on results predicted by models that only employ first-order sensitivities are likely to provide a false sense of confidence, unless such models also demonstrate quantitatively that the second- and higher-order sensitivities provide negligibly small contributions to the respective tolerance limits and confidence intervals. The high-order response sensitivities to parameters underlying large-scale models can be computed most accurately and most efficiently by employing the high-order comprehensive adjoint sensitivity analysis methodology, which overcomes the curse of dimensionality that hampers other methods when applied to large-scale models involving many parameters.


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