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Статті в журналах з теми "Tightness of Performance"
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Fletcher, James W. A., Lisa Wenzel, Verena Neumann, R. Geoff Richards, Boyko Gueorguiev, Harinderjit S. Gill, Ezio Preatoni, and Michael R. Whitehouse. "Surgical performance when inserting non-locking screws: a systematic review." EFORT Open Reviews 5, no. 1 (January 2020): 26–36. http://dx.doi.org/10.1302/2058-5241.5.180066.
Повний текст джерелаАнотація:
Billions of screws are inserted by surgeons each year, making them the most commonly inserted implant. When using non-locking screws, insertion technique is decided by the surgeon, including how much to tighten each screw. The aims of this study were to assess, through a systematic review, the screw tightness and rate of material stripping produced by surgeons and the effect of different variables related to screw insertion. Twelve studies were included, with 260 surgeons inserting a total of 2793 screws; an average of 11 screws each, although only 1510 screws have been inserted by 145 surgeons where tightness was measured – average tightness was 78±10% for cortical (n = 1079) and 80±6% for cancellous screw insertions (n = 431). An average of 26% of all inserted screws irreparably damaged and stripped screw holes, reducing the construct pullout strength. Furthermore, awareness of bone stripping is very poor, meaning that screws must be considerably overtightened before a surgeon will typically detect it. Variation between individual surgeons’ ability to optimally insert screws was seen, with some surgeons stripping more than 90% of samples and others hardly any. Contradictory findings were seen for the relationship between the tightness achieved and bone density. The optimum tightness for screws remains unknown, thus subjectively chosen screw tightness, which varies greatly, remains without an established target to generate the best possible construct for any given situation. Work is needed to establish these targets, and to develop methods to accurately and repeatably achieve them. Cite this article: EFORT Open Rev 2020;5:26-36. DOI: 10.1302/2058-5241.5.180066
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Curran, Hannah, and Stella Chapman. "Performance enhancing or unnecessary pressure?" Equine Health 2019, no. 47 (May 2, 2019): 26–31. http://dx.doi.org/10.12968/eqhe.2019.47.26.
Повний текст джерела
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Zheng, Xiao Tao, Jia Lin Zi Pan, and Jiu Yang Yu. "Effect of Gasket Compression Resilience on the Tightness of Bolted Flange System." Applied Mechanics and Materials 853 (September 2016): 328–34. http://dx.doi.org/10.4028/www.scientific.net/amm.853.328.
Повний текст джерелаАнотація:
Gasket is an important sealing element of bolted flange connection structure. The nonlinear performance of the gasket material will make the flange angle and gasket compression force change. Therefore, it plays an important role in the tightness of bolted flange connection system. Apart from acknowledgment of this effect, there exists no established design calculation procedure that accounts for tightness. In this paper, the mechanical properties of the gasket at room temperature were studied, it is known that the rebound performance of the gasket is related to the initial preload. And the effect of the compressive resilience of the gasket on the tightness of the bolt flange system was discussed. The tightness of the bolt flange system can be achieved by adjusting the initial preload and working pressure of the gasket, it provides the basis for design and evaluate the tightness of bolted flange connection system.
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Kim, Hyun-Bae, Joo-Saeng Park, Jung-Pyo Hong, Jung-Kwon Oh, and Jun-Jae Lee. "Air Tightness Performance of Residential Timber Frame Buildings." Journal of the Korean Wood Science and Technology 42, no. 2 (March 25, 2014): 89–100. http://dx.doi.org/10.5658/wood.2014.42.2.89.
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Zhang, Yan, Julien S. Baker, Xuejun Ren, Neng Feng, and Yaodong Gu. "Metatarsal strapping tightness effect to vertical jump performance." Human Movement Science 41 (June 2015): 255–64. http://dx.doi.org/10.1016/j.humov.2015.03.013.
Повний текст джерела
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Zhang, Zhixin, Qiang Guo, and Wei Liu. "Evaluation of Long-Term Tightness of the Coal Pillar Dam of Underground Reservoir and Protection Countermeasures." Energies 15, no. 19 (October 1, 2022): 7229. http://dx.doi.org/10.3390/en15197229.
Повний текст джерелаАнотація:
The coal mine underground reservoir is an effective facility for mine groundwater utilization in water-deficient and ecologically fragile areas. Usually, the artificial reserved coal pillar is used as the dam of underground reservoir, and little research has been done on its tightness performance. Comsol software is used to simulate the leakage of underground reservoirs in Shendong area, in the western part of China, and the long-term tightness of coal pillar dam under different operation conditions is evaluated. The results show that: (1) When the underground reservoir is not connected with the upper water system, the coal pillar dam has good tightness performance. When they are connected, the leakage of reservoir increased due to the raised water level, and the deeper the burial depth, the greater the leakage amount. (2) When reservoir is pumping and storing water, the leakage is only half of that under constant water pressure storage, indicating that this operation mode is beneficial to the long-term tightness of a coal pillar dam. (3) With the increase of the permeability of a coal pillar dam, the leakage will be aggravated. It is suggested that the permeability of a coal pillar dam should not exceed 1 × 10−15 m2. (4) The tightness of the coal pillar dam damaged by brine immersion is greatly reduced. With only 3 m of soaking damage distance, the total leakage is twice that of the undamaged one. For a coal pillar dam with poor tightness, some protection countermeasures are proposed to reduce the reservoir water level or improve the anti-seepage performance of a coal pillar dam, so as to ensure the long-term tightness of the dam. This research can provide theoretical support and technical guidance for evaluating the seepage stability of a coal pillar dam in an underground reservoir and strengthening its seepage control.
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Cao, Shuanghua, Zhiliang Lou, Leheng Wang, and Minsi Li. "The Research of Building Air Permeability Based on Building Structural Tightness." Advanced Materials Research 594-597 (November 2012): 2142–45. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.2142.
Повний текст джерелаАнотація:
The building air permeability plays a major role in both building energy performance and indoor air quality. The performance of structural tightness is set as an evaluation index of building air permeability, which is employed to analyze the relationship among building air permeability, building construction and window/door air permeability. Based on some assumptions, the coefficient of building structural tightness is established to summarize the influential factors on building air permeability, and the theory method is provided to improve the building air permeability. A model of air permeability for a small room is taken as an example. The results indicate that the building structural tightness coefficient is available to analyze the building air permeability.
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Dai, Li, and Yi Zhang. "The Influences of Material and Structure on the UV Protection of Summer Fabrics." Advanced Materials Research 298 (July 2011): 73–77. http://dx.doi.org/10.4028/www.scientific.net/amr.298.73.
Повний текст джерелаАнотація:
Thin summer fabrics without anti-UV finishing were used as experimental samples and the influences of fabric thickness, tightness, structure and fiber on the anti-UV properties were observed carefully. The measured performance parameters were normalized, to make UV protection properties of different thickness, tightness, fabric structures and fiber materials are comparable. This investigation revealed that the dominant factors affecting fabric anti-ultraviolet property were fabric structure, thickness and fiber type. The anti-UV performance from strong to weak is satin, twill and plain weave in terms of fabric structure; and polyester, silk, hemp and cotton in terms of fiber material. In addition, the anti-UV performances of fabrics positively increase with their thickness, when the other parameters were kept the same.
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Cheatham, Scott W., Kyle R. Stull, Mike Fantigrassi, and Ian Montel. "Hip Musculoskeletal Conditions and Associated Factors That Influence Squat Performance: A Systematic Review." Journal of Sport Rehabilitation 27, no. 3 (May 1, 2018): 263–73. http://dx.doi.org/10.1123/jsr.2016-0246.
Повний текст джерелаАнотація:
Context: The squat is a fundamental movement for weightlifting and sports performance. Both unilateral and bilateral squats are also used to assess transitional and dynamic lower-extremity control. Common lower-extremity conditions can have an influence on squat performance. Of interest are the effects of hip musculoskeletal conditions and associated factors, such as hip muscle pain, fatigue, and tightness, on squat performance. Currently, there has been no appraisal of the evidence regarding the association of these conditions and associated factors on squat performance. Objective: This study evaluated the current evidence regarding common hip musculoskeletal conditions and associated factors, such as hip muscle pain, fatigue, and tightness, on squat performance. Evidence Acquisition: A systematic review was conducted according to preferred reporting items for systematic reviews and meta-analyses guidelines. A search of PubMed, CINAHL, SPORTDiscus, ProQuest, and Google Scholar® was conducted in October, 2016 using the following keywords alone and in combination: hip, joint, arthritis, pain, range of motion (ROM), fatigue, tightness, pathology, condition, muscle, intraarticular, extraarticular, femoroacetabular impingement, single leg, bilateral, squat, performance, and technique. The grading of studies was conducted using the Physiotherapy Evidence Database scale. Evidence Synthesis: The authors identified 35 citations, 15 of which met the inclusion criteria. The qualifying studies yielded a total of 542 subjects (160 men and 382 women; mean age = 29.3 (5.9) y) and measured performance with either the barbell squat, step down, bilateral, or single-leg squat. Femoroacetabular impingement and hip arthroscopy were the only hip conditions found that affected the squat. Associated factors, such as muscle pain, fatigue, and tightness, also influenced squat performance. Conclusion: This review found that common hip conditions and associated factors and their effects on squat performance to be underinvestigated. Future research should focus on the association between common hip conditions and squat performance.
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Liu, Long Bin, Pan Pan Mi, Shuai Cao, and Ming Yun Lv. "Ground Simulation Method for Envelope Performance of Airship in near Space." Advanced Materials Research 989-994 (July 2014): 3473–76. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.3473.
Повний текст джерелаАнотація:
Performing characteristics on envelope composite of near space airship (NSA) are quite different from that of the low altitude airship essentially. The NSA envelope material should meet excellent applicative characteristics including light weight, high strength, anti-aging, anti-ultraviolet radiation, gas-tightness, weather resistance. Ground simulation test is critical for the envelope design and development process of NSA, and the environmental features of near space is analyzed for NSA, then corresponding ground simulation test methods are proposed to involve mechanical strength of the ground test methods among the changing weather temperature and over pressure changes, materials weather resistance and air tightness test. Finally the coupling relationship between various mechanical test and environmental test methods is also investigated.
Дисертації з теми "Tightness of Performance"
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Zhao, Xueqian. "Network on Chip : Performance Bound and Tightness." Doctoral thesis, KTH, Elektronik och Inbyggda System, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-166412.
Повний текст джерелаАнотація:
Featured with good scalability, modularity and large bandwidth, Network-on-Chip (NoC) has been widely applied in manycore Chip Multiprocessor (CMP) and Multiprocessor System-on-Chip (MPSoC) architectures. The provision of guaranteed service emerges as an important NoC design problem due to the application requirements in Quality-of-Service (QoS). Formal analysis of performance bounds plays a critical role in ensuring guaranteed service of NoC by giving insights into how the design parameters impact the network performance. The study in this thesis proposes analysis methods for delay and backlog bounds with Network Calculus (NC). Based on xMAS (eXecutable Micro-Architectural Specification), a formal framework to model communication fabrics, the delay bound analysis procedure is presented using NC. The micro-architectural xMAS representation of a canonical on-chip router is proposed with both the data flow and control flow well captured. Furthermore, a well-defined xMAS model for a specific application on an NoC can be created with network and flow knowledge and then be mapped to corresponding NC analysis model for end-to-end delay bound calculation. The xMAS model effectively bridges the gap between the informal NoC micro-architecture and the formal analysis model. Besides delay bound, the analysis of backlog bound is also crucial for predicting buffer dimensioning boundary in on-chip Virtual Channel (VC) routers. In this thesis, basic buffer use cases are identified with corresponding analysis models proposed so as to decompose the complex flow contention in a network. Then we develop a topology independent analysis technique to convey the backlog bound analysis step by step. Algorithms are developed to automate this analysis procedure. Accompanying the analysis of performance bounds, tightness evaluation is an essential step to ensure the validity of the analysis models. However, this evaluation process is often a tedious, time-consuming, and manual simulation process in which many simulation parameters may have to be configured before the simulations run. In this thesis, we develop a heuristics aided tightness evaluation method for the analytical delay and backlog bounds. The tightness evaluation is abstracted as constrained optimization problems with the objectives formulated as implicit functions with respect to the system parameters. Based on the well-defined problems, heuristics can be applied to guide a fully automated configuration searching process which incorporates cycle-accurate bit-accurate simulations. As an example of heuristics, Adaptive Simulated Annealing (ASA) is adopted to guide the search in the configuration space. Experiment results indicate that the performance analysis models based on NC give tight results which are effectively found by the heuristics aided evaluation process even the model has a multidimensional discrete search space and complex constraints. In order to facilitate xMAS modeling and corresponding validation of the performance analysis models, the thesis presents an xMAS tool developed in Simulink. It provides a friendly graphical interface for xMAS modeling and parameter configuring based on the powerful Simulink modeling environment. Hierarchical model build-up and Verilog-HDL code generation are essentially supported to manage complex models and conduct simulations. Attributed to the synthesizable xMAS library and the good extendibility, this xMAS tool has promising use in application specific NoC design based on the xMAS components.QC 20150520
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Allard, Ingrid. "Achieving building energy performance : requirements and evaluation methods for residential buildings in Sweden, Norway, and Finland." Licentiate thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-103749.
Повний текст джерелаАнотація:
Building energy performance has always been important in the cold climate of Sweden, Norway and Finland. To meet the goal that all new buildings should be nearly zero-energy buildings by 2020, set in the EU directive 2010/31/EU [1] on the energy performance of buildings (EPBD recast), the building sector in Europe now faces a transition towards buildings with improved energy performance. In such a transition, a discussion is needed about the objective of the improvement – why, or to what end, the building energy performance should be improved. The objective of improving building energy performance is often a political decision, but scientific research can contribute with knowledge on how the objectives can be achieved. This thesis addresses how the indicators used in the requirements used to achieve building energy performance in Sweden, Norway, and Finland, and the methods used to evaluate these requirements, reflect building energy performance. It also addresses difficulties in achieving comparable and verifiable indicators in evaluations of building energy performance. The research objective has two parts: to review, compare, and discuss (i) requirements and (ii) evaluation methods used to achieve energy performance of residential buildings in Sweden, Norway and Finland. The work in this thesis includes reviews of the requirements used in national building codes and passive house criteria to achieve building energy performance, of methods used to evaluate compliance with such requirements, and of methods used specifically to evaluate the indicator Envelope Air Tightness. The results show that different sets of indicators are used to achieve building energy performance in the studied building codes and passive house criteria. The methods used to evaluate compliance with requirements used to achieve building energy performance are also different, but calculation methods are generally more often used than measurement methods. The calculation- and measurement methods used are often simple. A methodology to analyze the deviation between predictions- and measurements of building energy performance (the performance gap) was developed, to investigate the effects of different evaluation methods on different indicators used to achieve building energy performance. The methodology was tested in a case-study. This study indicated that the choice of method affects which parts of the performance gap reflected in the indicators Supplied Energy (see Terminology), Net Energy (see Terminology), and Overall U-value. Among the reviewed methods to evaluate air tightness, the Fan/Blower Door Pressurization is well known and preferred by professionals in the field. The results in this thesis may be useful when choosing indicators and evaluation methods to achieve different objectives of improving building energy performance and in the quest towards comparable and verifiable indicators used to achieve building energy performance.Increasing Energy Efficiency in Buildings (IEEB)
Sustainable Buildings for the High North (SBHN)
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Giorgi, Priscila. "AVALIAÇÃO DE DESEMPENHO DE SISTEMA DE VEDAÇÃO VERTICAL DE BLOCO DE SOLO-CIMENTO CONFORME NBR 15575 REFERENTE À HABITABILIDADE E SUSTENTABILIDADE." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/7938.
Повний текст джерелаАнотація:
The Industrial Revolution generated two parallel phenomena during the twentieth century: increased distribution of wealth and reduced energy costs, causing a large increase in energy consumption. With the international oil crisis in the 1970s, materials used until that time such as concrete, steel and glass, began to be seen as energy-intensive materials. Society began to seek buildings with minimal environmental impact, using materials that generate a smaller amount of energy, waste and pollution and CO2 emissions in the atmosphere and provide greater potential for reincorporation into nature. In this scenario, raw soil as a building material has become an alternative for the development of sustainable buildings, but also to improve the livability of housing for the low-income population in the country. Among various construction materials, raw soil-cement, which is cured without burning, is raw soil pressed and stabilized with Portland cement, which is already regulated by the Brazilian Technical Standards Association (ABNT) and possesses many advantages related to its manufacturing and use. To increase its acceptance and verify its efficiency as a building material for social housing, it is necessary to investigate its properties and performance. Thus, the present study aimed to evaluate the performance of an external vertical sealing system composed of soil-cement blocks without structural function for social housing, following determinations of NBR 15575 (2013), focusing on the requirements of Habitability and Sustainability. The habitability require the heat action and thermal shock test. Firstly, using the particle size analysis and liquid limit and plastic limit test, to characterize the compostion of the ground on which the block was used. The bodies-of-proof were tested in The laboratory of Structural Models and Tests (Laboratório de Ensaios e Modelos Estruturais LEME), at the Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, and consisted of two full scale walls. The system met limits set by standards for tightness against rainwater and heat action and thermal shock, but not for permeability to water. The vertical sealing system composed of hollow blocks of soil-cement has great potential for application in the construction of social housing, but there is still a need for more studies on the system.A Revolução Industrial gerou, durante o século XX, dois fenômenos paralelos: a maior distribuição de riqueza e a diminuição do custo de energia, causando um grande aumento no consumo energético. Com a crise internacional do petróleo, na década de 1970, os materiais utilizados, até então, como concreto, aço e vidro, passam a ser vistos como materiais de grande consumo energético. A sociedade começa a buscar edificações com menor impacto ambiental possível, que utilizem materiais que envolvam baixo consumo energético, baixa geração de resíduos e poluentes, baixa emissão de CO2 na atmosfera e grande potencial de reincorporação na natureza. Diante desse cenário, a terra crua como material construtivo se torna uma alternativa para o desenvolvimento de edificações sustentáveis, como também, para a melhoria da habitabilidade das moradias da população de baixa renda existente no país. Das diversas técnicas de construção com a terra crua, o solo-cimento é um material curado sem queima, composto de terra crua prensada e estabilizada com cimento Portland, que já é normatizado pela Associação Brasileira de Normas Técnicas (ABNT), possuindo muitas vantagens que vão desde a fabricação até sua utilização no canteiro de obras. Para melhor aceitação e comprovação da sua eficiência como material construtivo para habitações de interesse social, é necessário que se conheça suas propriedades e seu desempenho. Dessa forma, a presente pesquisa consistiu em avaliar o desempenho de um sistema de vedação vertical externo composto por blocos de solo-cimento sem função estrutural para habitações de interesse social térreas, seguindo determinações da NBR 15575 (ABNT, 2013), focando nas exigências de Habitabilidade e Sustentabilidade. Como exigência de Habitabilidade analisou-se o fator Estanqueidade, com a realização dos ensaios de Estanqueidade à Água da Chuva e Permeabilidade à Água. E, como exigência de Sustentabilidade analisou-se os fatores Durabilidade e Manutenibilidade, com a realização do ensaio de Ação de Calor e Choque Térmico. Primeiramente, através de ensaio de análise granulométrica, limite de liquidez e limite de plasticidade, foi caracterizado o solo do qual o bloco utilizado é composto. Os corpos-de-prova foram ensaiados no Laboratório de Ensaios e Modelos Estruturais (LEME), da Universidade Federal do Rio Grande do Sul (UFRGS), em Porto Alegre, RS, e consistiram em duas paredes em escala real. O sistema atendeu aos limites estabelecidos pela norma nos ensaios de Estanqueidade à Água da Chuva e Ação de Calor e Choque Térmico, o que não ocorreu no ensaio de Permeabilidade à Água, no qual o sistema não atendeu às exigências. Através dos resultados dos ensaios verificou-se que o sistema de vedação vertical composto por blocos vazados de solo-cimento possui grande potencial para aplicação na construção, principalmente de habitações de interesse social, mas ainda há a necessidade de mais estudos sobre o sistema.
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Kuo, Po-Hung, and 郭柏宏. "The Effects of Standard Tightness and Compensation Scheme on Job Performance: The Moderating Effect of Risk-aversion and Task Complexity." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/55972333707413246648.
Повний текст джерелаАнотація:
碩士國立臺灣大學
會計學研究所
99
This study examines (1) the independent and joint effects of standard tightness and compensation scheme on job performance, (2) the role of risk-aversion in the above effects, and (3) whether the effect of risk-aversion on compensation scheme selection is moderated by task complexity. Recruiting 232 undergraduate students as the participants in an experiment in which some participants perform the decoding task (moderate complexity) while the others solve the arithmetic problem (high complexity), this study obtains the following findings. First, for the decoding task, only the interaction between standard tightness and risk-aversion has a significant effect on job performance. For the arithmetic problem, standard tightness, compensation scheme, and the interaction between compensation scheme and risk-aversion have significant effects on job performance. Further, after controlling for the effect of capability, risk-aversion affects compensation scheme selection in the arithmetic problem, but not the decoding task, suggesting that the effect of risk-aversion on compensation scheme selection varies with task complexity.
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Chao, Chia-Hung, and 趙家鴻. "The Study on the Relationships among the Degree of Tightness of Business Network, the Degree of Internationalization and Performance--from the Viewpoints of the Core Firms." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/73624891683339002660.
Повний текст джерелаАнотація:
碩士國立東華大學
國際企業研究所
90
Most researchers have been interested in exploring the content of the competitive advantage based on cooperative networks formed by small and medium enterprises（SMEs）in Taiwan. Firms obtain more benefits and advantages by using cooperative networks in competitive and dynamic environment. In addition, the activities of internationalization have become necessary requirements for SMEs to be survived under globalization pressure. Issues related internationalization have been received attention in international business management field. In this study, we attempted to propose hypotheses to explore the relationship among the relationship of the networks, the degree of internationalization and the performance of the enterprises. There are two main tasks of this study: first, to analyze the issue of the relationship among the networks, performance, and internationalization by empirical research of Taiwan’s manufacture from the view of the core firms; second, to offer suggestions to managers to set up strategies of network and internationalization to promote their performance. This empirical research was based on the survey and case studies methods. We collected 129 core firms enlisted in Taiwan’s Central Satellite manufacturers and the survey of the top 500 manufacturers in Taiwan by the Commonwealth Taiwan’s Learning Magazine, and analyzed the relationships among the degree of tightness of business network, the degree of internationalization and performance by using multiple regression method to test hypotheses. The analysis results showed that the degree of tightness of business network is significantly positively correlated with the adaptive performance, the financial performance and the degree of internationalization; the degree of internationalization is significantly positively correlated with the efficient performance, the adaptive performance and the financial performance. Moreover, we analyzed the marginal effects on the degree of tightness of business network and the degree of internationalization to performance, respectively. It showed that marginal effects decreased approximately but not significantly.
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Saha, Aadirupa. "Battle of Bandits: Online Learning from Subsetwise Preferences and Other Structured Feedback." Thesis, 2020. https://etd.iisc.ac.in/handle/2005/5184.
Повний текст джерелаАнотація:
The elicitation and aggregation of preferences is often the key to making better decisions. Be it a perfume company wanting to relaunch their 5 most popular fragrances, a movie recommender system trying to rank the most favoured movies, or a pharmaceutical company testing the relative efficacies of a set of drugs, learning from preference feedback is a widely applicable problem to solve. One can model the sequential version of this problem using the classical multiarmed-bandit (MAB) (e.g., Auer, 2002) by representing each decision choice as one bandit-arm, or more appropriately as a Dueling-Bandit (DB) problem (Yue \& Joachims, 2009). Although DB is similar to MAB in that it is an online decision making framework, DB is different in that it specifically models learning from pairwise preferences. In practice, it is often much easier to elicit information, especially when humans are in the loop, through relative preferences: `Item A is better than item B' is easier to elicit than its absolute counterpart: `Item A is worth 7 and B is worth 4'.
However, instead of pairwise preferences, a more general $k$-subset-wise preference model $(k \ge 2)$ is more relevant in various practical scenarios, e.g. recommender systems, search engines, crowd-sourcing, e-learning platforms, design of surveys, ranking in multiplayer games. Subset-wise preference elicitation is not only more budget friendly, but also flexible in conveying several types of feedback. For example, with subset-wise preferences, the learner could elicit the best item, a partial preference of the top 5 items, or even an entire rank ordering of a subset of items, whereas all these boil down to the same feedback over pairs (subsets of size 2). The problem of how to learn adaptively with subset-wise preferences, however, remains largely unexplored; this is primarily due to the computational burden of maintaining a combinatorially large, $O(n^k)$, size of preference information in general (for a decision problem with $n$ items and subsetsize $k$).
We take a step in the above direction by proposing ``Battling Bandits (BB)''---a new online learning framework to learn a set of optimal ('good') items by sequentially, and adaptively, querying subsets of items of size up to $k$ ($k\ge 2$). The preference feedback from a subset is assumed to arise from an underlying parametric discrete choice model, such as the well-known Plackett-Luce model, or more generally any random utility (RUM) based model. It is this structure that we leverage to design efficient algorithms for various problems of interest, e.g. identifying the best item, set of top-k items, full ranking etc., for both in PAC and regret minimization setting. We propose computationally efficient and (near-) optimal algorithms for above objectives along with matching lower bound guarantees. Interestingly this leads us to finding answers to some basic questions about the value of subset-wise preferences: Does playing a general $k$-set really help in faster information aggregation, i.e. is there a tradeoff between subsetsize-$k$ vs the learning rate? Under what type of feedback models? How do the performance limits (performance lower bounds) vary over different combinations of feedback and choice models? And above all, what more can we achieve through BB where DB fails?
We proceed to analyse the BB problem in the contextual scenario – this is relevant in settings where items have known attributes, and allows for potentially infinite decision spaces. This is more general and of practical interest than the finite-arm case, but, naturally, on the other hand more challenging. Moreover, none of the existing online learning algorithms extend straightforwardly to the continuous case, even for the most simple Dueling Bandit setup (i.e. when $k=2$). Towards this, we formulate the problem of ``Contextual Battling Bandits (C-BB)'' under utility based subsetwise-preference feedback, and design provably optimal algorithms for the regret minimization problem. Our regret bounds are also accompanied by matching lower bound guarantees showing optimality of our proposed methods. All our theoretical guarantees are corroborated with empirical evaluations.
Lastly, it goes without saying, that there are still many open threads to explore based on BB. These include studying different choice-feedback model combinations, performance objectives, or even extending BB to other useful frameworks like assortment selection, revenue maximization, budget-constrained bandits etc. Towards the end we will also discuss some interesting combinations of the BB framework with other, well-known, problems, e.g. Sleeping / Rotting Bandits, Preference based Reinforcement Learning, Learning on Graphs, Preferential Bandit-Convex-Optimization etc.
Книги з теми "Tightness of Performance"
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American, Society of Heating Refrigerating and Air-Conditioning Engineers. Air leakage performance for detached single-family residential buildings. Atlanta, GA: ASHRAE, 1988.
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American, Society of Heating Refrigerating and Air-Conditioning Engineers. Air leakage performance for detached single-family residential buildings. Atlanta, GA: ASHRAE, 1994.
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Ober, David G. Attic insulation performance: Full scale tests of conventional insulation and radiant barriers. Alexandria, VA: Mineral Insulation Manufacturers Association, 1990.
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Narila, Karfaid. Emphysema Symptoms: No Symptoms, Coughing, Chest Tightness, Shortness of Breath, Decreased Athletic Performance, Muscle Weakness, Wheezing, Excessive Mucus, Frequent Lung Infections, Blue-Tinged Lips and Fingernail Beds. Independently Published, 2021.
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Tarsia, Paolo. Dyspnoea in the critically ill. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0083.
Повний текст джерелаАнотація:
Dyspnoea may be defined as a subjective experience of discomfort associated with breathing. Breathing discomfort arises as a result of complex interactions between signals relayed from the upper airways, the chest wall, the lungs, and the central nervous system. Integration of this information with higher brain centres provides further processing. The final aspects of the sensation of dyspnoea are influenced by contextual, environmental, behavioural, and cognitive factors. At least three qualitatively distinct sensations have been employed to describe discomfort in breathing—air hunger, increased effort of breathing, and chest tightness. Air hunger has been shown to be associated with stimulation of chemoreceptors. Increased effort of breathing may arise in clinical conditions that impair respiratory muscle performance through abnormal mechanical loads or when respiratory muscles are weakened (neuromuscular diseases). Chest tightness is often experienced by asthmatic patients during episodes of acute bronchoconstriction. Measurement of dyspnoea is essential in order to assess it adequately and monitor response to treatment. Dyspnoea assessment may be carried out thorough a number of different scales, questionnaires, or exercise tests. Strategies in controlling dyspnoea should not focus uniquely on decreasing dyspnoea intensity. Patients may profit from interventions that decrease the unpleasantness associated with breathlessness without necessarily affecting the intensity component of the symptom.
Частини книг з теми "Tightness of Performance"
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Ammar, Hanen Ben, Omar Ayadi, and Faouzi Masmoudi. "Effect of Capacity Tightness on Performance of MOPSO Algorithm: Case of Multi-item Capacitated Lot-Sizing Problem." In Lecture Notes in Mechanical Engineering, 194–203. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-24247-3_22.
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Liu, Heng, Weiwen Xu, Hongtao Xu, and Xuemiao Xiang. "Numerical Analysis of Bearing Capacity of Basic Stress Unit Frame of Socket-Type Wheel Buckle Formwork Support Frame Body." In Lecture Notes in Civil Engineering, 151–60. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1748-8_12.
Повний текст джерелаАнотація:
AbstractSocket-and-socket wheel-buckle steel pipe formwork support frame is a new formwork support system, with fixed component specifications and fast erection speed, which can significantly improve the construction efficiency. Its application performance is different from that of fastener-type, bowl-buckle-type and plate-buckle-type, and there are not enough experimental and numerical analysis results to consult. Therefore, based on the bearing capacity test of the basic bearing units of socket-type wheel-buckle steel pipe formwork support, the finite element software ANSYS is used to conduct numerical analysis of 12 groups of basic bearing units, and the influence degree of vertical bearing capacity of different specifications of unit supports is studied by stud spacing and wedge tightness of cross bar plug. It is pointed out that the stiffness of formwork support in the vertical and horizontal directions should not be too different in the construction process.
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Holck, O., and S. Svendsen. "Rain Tightness." In Performance and Durability Assessment, 273–78. Elsevier, 2004. http://dx.doi.org/10.1016/b978-008044401-7/50020-1.
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Svendsen, S. "TESTING OF RAIN TIGHTNESS AND MECHANICAL PERFORMANCE OF SOLAR COLLECTORS." In Clean and Safe Energy Forever, 746–50. Elsevier, 1990. http://dx.doi.org/10.1016/b978-0-08-037193-1.50152-x.
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Devkota, P., J. Park, and E. Choi. "Effect of cracks on air-tightness of vacuum tube bridge structures." In Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges, 2799–804. CRC Press, 2018. http://dx.doi.org/10.1201/9781315189390-380.
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Ma, Ruizhe, Azim Ahmadzadeh, Soukaina Filali Boubrahimi, and Rafal A. Angryk. "Segmented Dynamic Time Warping." In Advances in Data Mining and Database Management, 1–19. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8446-9.ch001.
Повний текст джерелаАнотація:
Initially used in speech recognition, the dynamic time warping algorithm (DTW) has regained popularity with the widespread use of time series data. While demonstrating good performance, this elastic measure has two significant drawbacks: high computational costs and the possibility of pathological warping paths. Due to the balance between performance and the tightness of restrictions, the effects of many improvement techniques are either limited in effect or use accuracy as a trade-off. In this chapter, the authors discuss segmented-DTW (segDTW) and its applications. The intuition behind significant features is first established. Then considering the variability of different datasets, the relationship between specific global feature selection parameters, feature numbers, and performance are demonstrated. Other than the improvement in computational speed and scalability, another advantage of segDTW is that while it can be a stand-alone heuristic, it can also be easily combined with other DTW improvement methods.
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Guo, Yixiang, Lifang Chen, and Yuhang Zhou. "A Review of the Development of Sealing Materials and Measurement and Control Simulation Technology for Typical Hypersonic Vehicle Positions." In Proceedings of the 2022 International Conference on Smart Manufacturing and Material Processing (SMMP2022). IOS Press, 2022. http://dx.doi.org/10.3233/atde220826.
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Hypersonic vehicles are an important development direction in aerospace, and their development will have a significant impact on world security, the development of cosmic space resources and related disciplines. Along with the rapid development of modern aircraft, landing gear is commonly used with retractable technology, which brings a series of problems, such as the design of landing gear hatch retraction heat sealing mechanism and the evaluation of air tightness. This paper takes the thermal sealing structure of the front main landing gear hatch of a vehicle as an example, reviews the progress of the analysis techniques of sealing material properties and sealing structure design for hypersonic vehicles at home and abroad, discusses the current status of the development and limitations of hatch thermal sealing technology, outlines and discusses the key technologies for design and analysis of hatch thermal sealing structure and the future development trend, and summarizes the test equipment and methods for identifying the performance of seals and sealing systems.
Тези доповідей конференцій з теми "Tightness of Performance"
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Li, Xiang, Cheng Yao, and Jiepu Li. "Research on Tightness Performance of Corrugated Gasket Bolted Flanged Connections System." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63794.
Повний текст джерелаАнотація:
A finite element calculation and a leakage rate test were carried out in order to investigate the tightness performance of a corrugated gasket bolted flanged connections system. Based on a detailed finite element model of the bolted flange connection, gasket stresses and deformations were determined for room temperature operating conditions. Leakage testes were then performed to acquire leakage data at different gasket compression stresses and different internal pressures. The data was fit to a leakage rate formula. Additional analysis was performed to investigate the influence of temperature.
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Finegan-Dollak, Catherine, Reed Coke, Rui Zhang, Xiangyi Ye, and Dragomir Radev. "Effects of Creativity and Cluster Tightness on Short Text Clustering Performance." In Proceedings of the 54th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). Stroudsburg, PA, USA: Association for Computational Linguistics, 2016. http://dx.doi.org/10.18653/v1/p16-1062.
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Zheng, Xing, Koji Sato, Takahiro Fujihara, Yoshiko Akamatsu, and Toshiyuki Sawa. "Effect of Tightening Procedure on the Sealing Performance of Bolted Gasketed Pipe Flange Connections." In ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-93497.
Повний текст джерелаАнотація:
Abstract The objective of the present paper is to examine the effect of tightening procedure on scatter in axial bolt forces and the bolt forces distribution in bolted gasketed pipe flange connections where spiral-wound gaskets and PTFE blended gaskets are used. The scatter in the axial bolt forces was examined by several tightening procedures which are JIS B 2251, ASME PCC-1 legacy, ASME alternative #1, #2, #3 and 3 rounds method procedures in ASME 24“ bolted gasketed pipe flanged connection. The leak rate of the tightened bolted flanged connections was also measured. Furthermore, the assembly efficiency based on both axial bolt forces and the tightness parameters of the bolted pipe flange connections was calculated and compared. The obtained results are as following. First, the leak rate of the connection tightened by JIS procedure is the lowest of all the tightening procedures. Second, the assembly efficiency based on axial bolt forces tightened by JIS procedure is the highest, and the assembly efficiency based on tightness parameters according to JIS procedure is also the highest. Third, the assembly efficiency based on tightness parameters is smaller than that based on the axial bolt forces. As a conclusion, the JIS B 2251 procedure is the most efficient tightening procedure of all the tightening procedures tested in the present study and the assembly efficiency based on the tightness parameters is suggested to design bolted connections for more safety.
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Cheta, Ayman M., and Gonghyun Jung. "Comparative Study of Leak-Tightness Performance of Wafer Type and Lug-Wafer Type Valves During a Fire." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78177.
Повний текст джерелаАнотація:
Many companies do not allow the use of wafer type valves in flammable and/or toxic services. During a fire, the long bolts expand faster than the valve body, causing the joint to lose tightness and making the fire bigger. However, there is no consensus with regard to wafer-lug type valves. Some companies believe that since the bolts are protected inside the lugs the problem is solved. Others believe than the long bolts will always be a problem. In this paper, the authors used finite element analysis to compare the leak-tightness performance of both types during a fire.
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Kobayashi, Takashi, Koji Sato, Akira Muramatsu, and Toshiyuki Sawa. "Reduction of Fugitive Emissions From Bolted Flanged Connections by Using PTFE Blended Gasket." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63547.
Повний текст джерелаАнотація:
Gasket is the key element which determines the tightness of bolted flanged connection. PTFE blended gaskets which have recently been developed and come onto the market have a superior sealing performance as well as the chemical and temperature resistances and can contribute to reduce fugitive emissions. This paper deals with the sealing behaviors of the PTFE blended gasket and the tightness of a bolted flanged connection in which the gasket is used. The gasket is mainly composed of PTFE and graphite and has a high tightness and heat resistance up to 300 degree C. The creep characteristic is improved by the graphite filler. In this paper, the estimation method of the tightness of bolted flanged connections based on the sealing behavior of gasket is demonstrated. The estimated results are validated by experiments using a flange connection. It is shown that the leak rate below the tightness class 4 defined in the Room Temperature Tightness Test (ROTT, Pressure Vessel Research Council) can be obtained using the PTFE blended gasket.
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Lee, Walter, Abdel-Hakim Bouzid, and James Huang. "Qualification of Gasket Performance for Vacuum Applications." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-26056.
Повний текст джерелаАнотація:
Gasket performance for vacuum applications has not been well studied. Although a wealth of sealability data has been generated for pressurized systems, little is done with vacuum conditions. A new test method has been developed to study the sealing performance of gaskets for vacuum services. The tests were conducted on a standard ROTT test rig, where a vacuum chamber surrounding the gasket was created by an air pump and monitored by a pressure gauge capable of measuring pressures down to 0.1 Torr. Two levels of vacuum were used: 50 Torr and 3 Torr. Each tested gasket was compressed to various assembly stresses corresponding to the levels defined in the ROTT procedure. After the gasket was compressed to a desired stress and a target vacuum level was reached, the pumping stopped, and the leak rate was measured, using the pressure rise method. The similar leakage results with two very different vacuum levels confirm that sealing a vacuum system is simply to seal ∼1 bar of air. The air leakage was further compared with the helium leak rates obtained from the standard ROTT test with a pressure of 21 bar to determine the correlation between the two data sets. To better understand the effects of pressure and molecular size of a gas, two additional tests at 2 bar, with helium and with nitrogen, were performed. The comparison among all test data suggests that the gases at relatively low pressures follow a molecular flow behavior up to about 55 MPa of gasket stress on the tested material. As a result, a tightness curve that can be used to estimate the vacuum leakage has been established. For applications involving elevated temperatures, thermal behaviors of gaskets determined by other PVRC tests, such as the HOBT and ARLA, can be used to understand the impact of temperature on vacuum performance. A stress-tightness-temperature framework is proposed that can be used to estimate the tightness and leakage of the gasket at high temperatures. Knowing the air leak rates under different operating conditions, a gasket user will be able to determine the suitability of the gasket for a specific vacuum requirement as well as the optimal assembly stress to maintain the desired vacuum level.
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Strebkov, S. V., A. P. Slobodyuk, and A. V. Bondarev. "RESTORING THE PERFORMANCE OF ALUMINUM RADIATORS OF THE COOLING SYSTEM." In Innovative technologies in road transport. Voronezh State University of Forestry and Technologies named after G.F. Morozov, Voronezh, Russia, 2021. http://dx.doi.org/10.34220/itrt2021_92-97.
Повний текст джерелаАнотація:
The article is devoted to the development of a technology for repairing an aluminum radiator of a KAMAZ vehicle. A distinctive feature of the proposed technology is the use of cold gas-dynamic spraying, which ensures the restoration of the tightness of a radiator made of thin-walled aluminum parts and having a complex shape that makes it difficult to perform technological operations.
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Dupre, Ross. "Effects of Stud Galling on Bolted Flange Joint Assembly Performance." In ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21248.
Повний текст джерелаАнотація:
Abstract This study will focus on the galling of studs and what impact that has on the overall performance of a Bolted Flange Joint Assembly. Galling or “cold welding” occurs more so with softer metals. While tightening the nut on to the stud the contact metal will “pull” away from itself and the two surfaces will essentially become one. Once this happens the nut cannot be tightened or loosened and often cutting the stud is the only form of removal. We’ll be studying how this affects the performance (tightness) of a bolted flange joint assembly. Does the assembly loosen over time or does it remain at the proper tightness? Data will be captured using load cells to accurately represent the amount of force being generated by test studs. There will be a standard test ran with no galling. All other tests with galled studs will be measured and compared against the standard test. One test with only one stud galled, the next with two studs galled, the next with three studs galled, and so on. It may be expected to see some load loss on the load cells with the galled studs. The integrity of the studs, once galled, becomes less than ideal.
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Rice, Dale A., and A. Fitzgerald Waterland. "Review of Mechanical and Sealing Performance Aspects of Commercially Available PTFE Based Gasket Materials." In ASME 2018 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/pvp2018-84082.
Повний текст джерелаАнотація:
Gaskets incorporating polytetrafluoroethylene (PTFE) are one of the most common in use today where soft sealing material is needed in bolted joints. Over the years, various types of gaskets have been developed including those using skived, expanded, filled, or molded PTFE sheet. Still other PTFE gaskets have been fabricated, incorporating some type of metal insert. Although many of the key benefits (e.g., chemical resistance, application in a broad range of flange types, higher maximum temperature and stress levels than most elastomers, indefinite shelf life, etc.) remain, the performance of the gasket will vary significantly according to the type of PTFE gasket employed. These variations in accordance with PTFE gasket styles are presented and discussed with an emphasis on such criteria as relaxation, gasket tightness / leak rate, and safe reserve operating temperature. For estimating tightness and predicted leak rates, the previously reported “Fugitive Emissions Calculator” (FEC) model has been used which employs Room Temperature Testing (ROTT) data and an ASME / PVRC draft empirical equations set. Published test data have also been compiled to support conclusions concerning relative capabilities for selected PTFE gasket categories. The differences in analytical and leak rate performance criteria have been used to suggest appropriate applications for various subtypes of PTFE gaskets.
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Bausman, Anita, Jerry Waterland, and Dan Reid. "New Leakage Requirements for ASME B16.20 and Current Generation Spiral Wound Gaskets." In ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-93928.
Повний текст джерелаАнотація:
Abstract The ASME B16.20 Metallic Gaskets for Pipe Flanges standard was extensively revised in 2017 [1]. One of the significant changes is the introduction of maximum permissible leakage rate. This marks a landmark introduction of an actual leakage performance criterion into ASME B16.20, a most welcome advance. A common maximum permissible leakage rate of 0.0137 mg/s-m (7.67E−10 lb/s-in) is specified for all sizes and pressure classes of finished spiral wound gaskets, that is, including the windings and any or no gauge rings for that particular gasket. Test conditions are defined — ambient temperature and calibration gas with a known methane concentration and flow rate of 1 L/min. The test pressure is defined by the pressure class: 20 bar (290 psi) for Class 150 and 40 bar (580 psi) for Class 300 and above. The qualification parameters listed in B16.20-2017 include prescribed gasket seating stress targets which also vary by pressure class. These gasket seating stress requirements are defined as 35 MPa (5,000 psi) for Class 150, 56 MPa (8,000 psi) for Class 300 and Class 400, and 70 MPa (10,000 psi) for Class 600 and above. Three questions will be explored in this paper. First, to what tightness does the new B16.20 spiral wound gasket leakage rate criterion correspond? Second, do current generation spiral wound gaskets meet this criterion? Several commercially available spiral wound gaskets will be analyzed and compared to the new B16.20 requirements. Leak rates and tightness at the new B16.20 performance qualification test conditions can be determined using publicly available, published Room Temperature Tightness (ROTT) test constants for these gaskets. Finally, an exploration of Assembly Tightness compared to Operating Tightness for a selection of spiral wound gaskets will be presented and compared to the new B16.20 Performance Testing requirements. This exploration of the new maximum leakage performance criterion in ASME B16.20-2017 will help to familiarize the end user with a valuable new aspect of this gasket standard as well as how the current generation of spiral wound gaskets meets that criterion using publicly available ROTT performance data.
Звіти організацій з теми "Tightness of Performance"
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Sekki, Pauli, Eero Saleva, and Pekka Laamanen. Study of ventilated low-slope and large span wooden element roofs in the current and future climate. Department of the Built Environment, 2023. http://dx.doi.org/10.54337/aau541620957.
Повний текст джерелаАнотація:
Finland's building regulations and guidelines rely on ventilation to ensure the hygrothermal performance of structures. For wooden roofs, height of ventilation cavity and area of ventilation openings have been determined depending on roof slope and roof area in guideline. This causes difficulties in practical implementation in low-slope roofs with large span, because the guideline leads to large ventilation openings that can be challenging to be implemented. In practice, roof element suppliers have produced roofs with slightly smaller height of ventilation cavities and areas of ventilation openings. This study examined the hygrothermal behavior of the ventilated wooden roof, where the role of airtightness of vapor barrier and ventilation rate were investigated. The ventilation rates of the simulation model were set based on the results of longterm continuous measurement. First, to ensure the applicability of used model, the mold index calculated from measurements was compared to simulated with the design weather data. Next, hygrothermal behavior was evaluated based on mold index using the design climate data (current and future) for airtight and 'loose' structure with various ventilation rates. Results shows that focusing on airtightness is important. However, the larger ventilation rate has an unfavorable effect on mold index which is emphasized in future climate. Thus, revision of the design guidelines is proposed to restrict the ventilation openings and unnecessarily effective ventilation. In addition, air tightness guidelines should be set more precisely from the perspective of moisture safety.