Thèses : « Piping analysi »

1

Robinson, Louise Anne. « Genetic analysis of the critically endangered Trinidad Piping guan (Pipile pipile) : implications for phylogenetic placement and conservation strategies ». Thesis, University of Chester, 2011. http://hdl.handle.net/10034/346901.

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Classified as critically endangered since 1994, the Trinidad Piping guan (Pipile pipile) is an endemic species estimated to number less than 200 individuals. Known to locals of Trinidad as the ‘Pawi’ this bird has been the subject of substantial hunting pressures and much of the species habitat has been destroyed through deforestation. Although officially protected since 1958, occasional recreational hunting of this elusive species still occurs. Due to difficulties locating and capturing the species, no genetic research has previously been performed using samples obtained from Trinidad. All previous research studies have been conducted using biological materials obtained from captive birds outside Trinidad and island data has never been obtained or compared. The genetic diversity of the remaining population was therefore examined through the investigation of mitochondrial haplotypes, pairwise comparison and SNP analysis. With the intention of assisting the protection of this endangered species by the location of remaining areas of habitation, methods of genetic identification were established for the Trinidad Piping guan utilising non-invasive feather samples. Species specific primers were created in the regions of the ND2 and cyt b genes of the mitochondrial genome to identify Pipile pipile. Species detection was further verified with the use of PCR-RFLP of the same gene regions digested with BsaXI, EcoRV and BsrDI. This combined approach allowed the separation of closely related taxa based on single inter-species SNPs. Confirmation of species identification was subsequently performed through the use of forensically informative nucleotide sequencing. The established methodologies were used in the current study to correct the classification of a UK breeding population of Piping guans thought to be Pipile pipile and to identify Trinidad field samples. These detection methods have implications for ecological studies through the location of populations from trace evidence collected in the field. In addition this method could be used to assist Trinidadian police forces in the identification of bushmeats or simply act as a deterrent to hunters. The sequence data obtained in the present study were also used to re-assess the phylogeny of Piping guans. As genetic sequence from a true island bird was previously unstudied, differences between phylogenies created using non-island and island bird data sets were examined. Combined analysis was performed on 1884bp of the ND2 and cyt b genes and placement of Trinidad Piping guan was found to differ from that which has been previously published.

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Borhani, Khomami Arghavan. « Separate analysis of Small Pipes in Piping Analysis ». Thesis, KTH, Hållfasthetslära (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177355.

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A piping system generally consists of primary system, large pipes, and secondary system, small pipes [1]. The primary system can be analysed separately without considering the secondary system. However, the opposite is not true because the primary system affects the movement of the secondary system. The aim of this study is to investigate the possibility of analysing the small pipes separately, which is called for sub-modelling, and then if the sub-modelling is possible, generate and validate a method which makes this sub-modelling possible. The response spectrum method [2] is used for analysing the structure. A ground acceleration spectra in three directions is applied at the primary structure, a new floor response spectra is then generated with the results from the analysis of the primary structure [3]. The calculated floor response spectra is applied at the secondary structure. The results from this analysis is compared to the results from applying the ground acceleration at the total structure. Two different ground accelerations are applied on two different models. A separation would be allowed if the results of the secondary structure are more than 90% of the results of the whole structure in all parts of the secondary structure in all studied cases. The results after separation reach more than 100% of the results from the analysis of the whole structure, called for conservative results, in three cases but not all the cases. The separation will be allowed in those three cases where the results reach 90% of the results taken from the whole structure, but not in that case where results does not reach 90%.
Vanligtvis består ett rörsystem av ett primärsystem, stora rör, och ett sekundärsystem, klena rör. Det primära systemet kan analyseras separat utan att ta hänsyn till det sekundära systemet. Men det är inte möjligt att analysera det sekundära systemet utan att ta hänsyn till det primära, eftersom det primära systemet påverkar rörelsen av det sekundära systemet. Syftet med denna studie är att undersöka möjligheten att analysera de små rören separat, och sedan om denna separation är möjligt, skapa och validera en metod som gör denna separation möjligt. Metoden responsspektrum används för att analysera strukturen. En grundacceleration spektra i tre riktningar tillämpas på den primära strukturen, sedan genereras ett nytt spektra med resultaten från analysen av den primära strukturen. Den beräknade responsspektra appliceras sedan på den sekundära strukturen. Resultaten från denna analys jämförs med resultaten från applicering av grundaccelerationen på den totala strukturen, när den primära och sekundära strukturen sitter ihop. Två olika grundaccelerationer appliceras på två olika modeller. Separationen kommer att tillåtas om resultaten av den sekundära strukturen är mer än 90% av resultaten från hela strukturen i alla delar av den sekundära strukturen i samtliga studerade fall. Resultaten efter separationen uppnår till mer än 100% av resultaten från analysen av hela strukturen, kallad för konservativa resultat, i tre fall men inte alla de studerade fallen. Separationen kommer att tillåtas i de tre fallen där resultaten når 90% av resultaten som tagits från hela strukturen, men inte i det fallet där resultaten inte når 90%.

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Mandela, Ravi Kumar. « Uncertainty analysis of piping systems and heat exchanger networks ». abstract and full text PDF (free order & ; download UNR users only), 2004. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1433382.

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4

Zhao, Yong. « Random vibration for seismic analysis of multiply supported nuclear piping ». Case Western Reserve University School of Graduate Studies / OhioLINK, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=case1061299266.

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Petrusek, Tomáš. « Analysis of the innovation management at Georg Fischer Piping Systems ». Master's thesis, Vysoká škola ekonomická v Praze, 2008. http://www.nusl.cz/ntk/nusl-3955.

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6

Moffat, Douglas G. « Stress analysis and design of some pressure vessel and piping components ». Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248755.

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7

Mantegh, Iraj. « Stochastic analysis of multiply-supported piping systems under correlated ground excitations ». Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6795.

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Piping systems are among the most important systems in modern industrial facilities, which are also highly affected by events like earthquakes, hurricanes, flood, etc. Like nerves in our body they nurture the industrial plants and hence require protection from these events. For dynamic and specially seismic loading there is no universally accepted design code, hence research is still underway in this area. The response of a system excited by ground motions has two components: (1) pseudo-static which is due to the ground displacement at support points and (2) dynamic which is due to the vibrational excitation. The current methods of estimating that response are typically based on the assumption of a uniform ground motion. Some authors have recently attempted to modify the methods for the spatial variations of ground motion. In this work a different method is presented which also considers the non-uniformity in support excitations. The treatment is based on the random vibration principles and can develop the pseudo-static time history of the system and also the maximum dynamic response at each degree of freedom. For a typical piping system, the correlated ground acceleration and displacement time series are developed at the excited support points. The time series are used to develop the pseudo-static component, and also for the dynamic component by means of a classical step-by-step integration method. Dynamic responses are also developed by the stochastic method and some current methods and are compared, in each case, with the results from the integration method. It is verified that the stochastic results are comparable with the current method results. Comparing the results in case of a uniform and a non-uniform ground motion, it is shown that the cross correlation of support inputs does affect the components of the response significantly and the effect is not predictable. It is also shown that neglecting the non-uniformity in ground motions can lead to an underestimation of results, in some cases, while in some other cases to an overestimation.

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See, P. S. « The analysis of piping systems on a microcomputer using pipe bend elements ». Thesis, University of Strathclyde, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371380.

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9

VALVERDE, MARCELO CERQUEIRA. « DEVELOPMENT OF RESPONSE SPECTRA FOR THE SEISMIC STRUCTURAL ANALYSIS OF PIPING SYSTEMS ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1998. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=1469@1.

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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
NUCLEN S.A.
Os resultados apresentados referem-se à investigação dos mecanismos de interação entre dois sistemas vitais às usinas nucleares, ou seja: os sistemas Principal (SP) e o Secundário (SS). Estes mecanismos são avaliados por meio de sua influência nos espectros de resposta, em pontos da estrutura passíveis da existência de suportes das linhas de tubulação - SS. São usados dois tipos diferentes de análises para a geração dos espectros de resposta: a primeira não considera a interação dos sistemas e a segunda avalia esta interação com a introdução, em cada ponto de suporte no SP, de um S1GL com suportes únicos ou com multi- suportes. As respostas estruturais são obtidas por integração direta da equação de movimento do sistema sujeito a dois acelerogramas simultâneos, nas direções horizontal e vertical. Os resultados são analisados e comparados para identificação das principais tendências das análises e esclarecimento dos efeitos envolvidos. Estuda-se, também, a importância de não- linearidades concentradas nos suportes da tubulação, tendo- se em vista o nível sísmico a que as centrais nucleares brasileiras estão sujeitas.
The results presented in this work refer to the investigation of the mechanics of the interaction between two important systems of nuclear power plants, i.e.: the Primary (PS) and Secondary (SS) systems. The influence of these effects on the response spectra is studied, in convenient points of the structure where could exist pipeline (SS) supports. Two different approaches are used to generate the response spectra: the first neglects the interaction between the two systems and the second considers this interaction by the addition, to every support point on the PS, of a single-supported or multi-supported SDOF system. The structural responses are obtained by the direct integration of the Primary System equations of motion subjected to two simultaneous design acceleration time-histories, in the horizontal and vertical directions. The results are analyzed and compared to identify the general trends of the solutions obtained by the two types of analysis, and to detect their effects on the SS response. The study is concerned, also, with the importance of nonlinearities concentrated in the pipeline supports; in the case of the Brazilian nuclear power plants.
Los resultados presentados se refieran a la investigación de los mecanismos de interacción entre de los los sistemas Principal (SP) y el Secundario (S) de las plantas nucleares. Estos mecanismos son evaluados por medio de su influencia en los espectros de respuesta, en puntos de la extructura donde es posible(pausibles) la existencia de soportes de las líneas de tuberías - S. Son usados dos tipos diferentes de análisis para la generación de los espectros de respuesta: la primera no considera la interacción de los sistemas y la segunda evalúa esta interacción con la introdución, en cada ponto de soporte en el SP, de un S1GL con soportes únicos o con multisoportes. Las respuestas extructurales son obtenidas por integración directa de la ecuación de movimento del sistema sujeto a dos acelerogramas simultáneos, en las direcciones horizontal y vertical. Se analizan los resultados y se comparan para identificar las principales tendencias del análisis y esclarecer los efectos involucrados. Se estudia además, la importancia de no linealidades concentradas en los soportes de la tubería, teniendo en vista el nível sísmico a que las centrales nucleares brasileras están sujetas.

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OJEDA, WALDO JIM GASTANAGA. « EVALUATION OF SOME DESIGN METHODS FOR MODAL SPECTRAL SEISMIC ANALYSIS OF PIPING SYSTEMS ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1998. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=1414@1.

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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
NUCLEN S.A.
Apresenta-se um estudo de avaliação dos critérios e métodos que são empregados atualmente na análise e projeto dos sistemas de tubulação nas usinas nucleares assim como a verificação da aplicação de alguns dos novos critérios apresentados pela comunidade técnico-científica internacional, dentro do método de análise modal-espectral. Estudam-se os tópicos da interação entre o sistema de tubulação e a estrutura que o suporta mediante o uso de espectros acoplados, a consideração do efeito do deslocamento relativo dos apoios da tubulação, usando-se espectros que o consideram ou uma excitação espectral múltipla, a introdução da combinação dos máximos modais dependendo da posição relativa das suas freqüências e a inclusão da resposta espectral correspondente aos modos de alta freqüência ou modos rígidos. A ferramenta básica de análise é constituída pelo programa computacional ANSYS. A avaliação é feita sobre parâmetros de esforços internos em trechos de um modelo de um sistema real de tubulações da usina nuclear brasileira, Angra 3. Os padrões são obtidos por análises no tempo de cada modelo sob o acelerograma de projeto. Conclusões são apresentadas sobre as atitudes mais convenientes para a atual conjuntura brasileira de projeto.
The main concern of this work is with the application of the modal spectral seismic analysis to secondary structural systems of nuclear power plants, with the large amount of conservatism which is included in them, and, of course, with the consequences to the particular case of the plants under construction in Brazil. One considers the design analysis methods which have been used so far in Brazil, as well as the most recent developments in the area, in USA and in Europe, to conclude about the adequacy of those procedures and recommend eventual changes to them. One then studies the subjects of the coupling effect between the primary and secondary system responses, the influence of the piping support relative displacements, the contribution of the cross-correlation among response modal components and the participation in the overall response of the so-called rigid modes. The main computer program aid is taken from an ANSYS-2 version and one uses a reduced model of a piping system as the secondary system and a 3-D beam element model of a reactor building as the primary system. The spectral analysis results are compared to time domain solutions using the same structural models excited by a design accelerogram. Conclusions and recommendations are oriented to the present design practice in Brazil.
En esta tesis se presenta un estudio de evaluación de los criterios y métodos que se emplean actualmente en el análisis y proyecto de los sistemas de tubulación en las plantas nucleares así como la verificación de la aplicación de algunos de los nuevos criterios presentados por la comunidad técnico-científica internacional, dentro del método de análisis modal-espectral. Se estudian los tópicos de la interacción entre el sistema de tubulación y la extructura que él soporta mediante el uso de espectros acoplados; la consideración del efecto de deslocamiento relativo de los apoyos de la tubulación, utilizando espectros que lo consideran o una excitación espectral múltipla; la introdución de la combinación de los máximos modales dependiendo de la posición relativa de las sus frecuencias y la inclusión de la respuesta espectral correspondiente a los modos de alta frecuencia o modos rígidos. La herramienta básica de análisis es el programa computacional ANSYS. La evaluación se realiza sobre parámetros de esfuerzos internos en trechos de un modelo de un sistema real de tuberías de la planta nuclear brasilera, Angra 3. Los padrones se obtienen por análisis en el tiempo de cada modelo bajo el acelerograma de proyecto. Se presentan conclusiones sobre las actitudes más convenientes para la actual conyuntura brasilera.

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Catlin, Daniel Herbert. « Population Dynamics of Piping Plovers (Charadrius melodus) on the Missouri River ». Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/27442.

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Habitat loss and predation are threatening many shorebird populations worldwide. While habitat preservation often is preferable, sometimes habitat needs to be restored or created in order to stave off immediate declines. The Great Plains population of piping plovers (Charadrius melodus) was listed as threatened in 1986, and habitat loss and predation appear to be limiting the growth of this population. On the Missouri River, piping plovers nest on sandbars, but the damming of the mainstem of the Missouri in the mid-twentieth century reduced the natural capacity of the Missouri River to create sandbar habitat. In 2004, the United States Army Corps of Engineers (USACE) implemented a habitat creation project on the Gavins Point Reach of the Missouri River (stretch of river immediately downriver from the Gavins Point Dam) in an effort to promote recovery of piping plovers and the endangered least tern (Sternula antillarum). The USACE built 3 sandbars in 2004 â 2005 and built another sandbar on Lewis and Clark Lake in 2007. We studied the population dynamics of piping plovers in relationship to this newly engineered habitat. We monitored 623 nests on 16 sandbar complexes, to evaluate habitat selection, determine the factors affecting nesting success, and compare nesting success between natural and engineered habitat. From these 623 nests, we banded 357 adults and 685 chicks to investigate the factors affecting adult and juvenile survival. We used a logistic-exposure model to calculate nest survival. Adult and juvenile survival was calculated using Cormack-Jolly-Seber based models in Program MARK. We used the estimates from these studies to create a matrix population model for piping plovers nesting on the Gavins Point Reach. We used this model to predict the effects of engineered habitat on the population growth rate. Piping plovers selected for engineered sandbars and against natural and natural/modified habitats. Daily survival rate (DSR) on engineered habitats was significantly higher than on natural or natural modified habitats (log odds: 2.71, 95% CI: 1.20 â 6.08). Predator exclosures around nests did not affect DSR after controlling for the effects of date, nest age, and clutch size. Piping plover juvenile survival to recruitment was negatively related to nesting density on the relatively densely populated engineered sandbars. On the less dense natural sandbars, survival to recruitment was positively correlated with density. Adult survival did not appear to be related to density within our study. Movement within the study area was related also to density. Juveniles from densely populated engineered sandbars were more likely to leave engineered habitat to nest on natural sandbars than were juveniles hatched on less densely populated engineered sandbars. Movements among sandbars by breeding adults suggested that adults preferred engineered habitat. It is possible that juveniles moved to natural habitats because they were unable to compete with adults for the more desirable engineered habitats. Adults and juveniles emigrated from the study area at a higher rate after the 2006 breeding season, a year when water discharge was higher, nesting densities were higher, and reproductive success was lower (as a result of predation) than in the other years. Deterministic modeling suggested that engineered habitat significantly increased population growth. Decreased productivity over time and associated predicted negative population growth suggest that the amount of engineered habitat created was inadequate to sustain population growth, and/or that relatively high water discharge and nesting densities coupled with low reproductive rates and high emigration rates could lead to rapid declines in the plover population. Continued research is needed to determine the effects of these factors on long-term population growth. Our results suggest that habitat creation could be a viable short-term solution to population declines in shorebird populations limited by habitat loss, but high densities and increased predation associated with habitat creation indicate that other, long-term solutions may be required.
Ph. D.

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12

Catlin, Daniel H. « Population Dynamics of Piping Plovers (Charadrius melodus) on the Missouri River ». Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/27442.

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Habitat loss and predation are threatening many shorebird populations worldwide. While habitat preservation often is preferable, sometimes habitat needs to be restored or created in order to stave off immediate declines. The Great Plains population of piping plovers (Charadrius melodus) was listed as threatened in 1986, and habitat loss and predation appear to be limiting the growth of this population. On the Missouri River, piping plovers nest on sandbars, but the damming of the mainstem of the Missouri in the mid-twentieth century reduced the natural capacity of the Missouri River to create sandbar habitat. In 2004, the United States Army Corps of Engineers (USACE) implemented a habitat creation project on the Gavins Point Reach of the Missouri River (stretch of river immediately downriver from the Gavins Point Dam) in an effort to promote recovery of piping plovers and the endangered least tern (Sternula antillarum). The USACE built 3 sandbars in 2004 â 2005 and built another sandbar on Lewis and Clark Lake in 2007. We studied the population dynamics of piping plovers in relationship to this newly engineered habitat. We monitored 623 nests on 16 sandbar complexes, to evaluate habitat selection, determine the factors affecting nesting success, and compare nesting success between natural and engineered habitat. From these 623 nests, we banded 357 adults and 685 chicks to investigate the factors affecting adult and juvenile survival. We used a logistic-exposure model to calculate nest survival. Adult and juvenile survival was calculated using Cormack-Jolly-Seber based models in Program MARK. We used the estimates from these studies to create a matrix population model for piping plovers nesting on the Gavins Point Reach. We used this model to predict the effects of engineered habitat on the population growth rate. Piping plovers selected for engineered sandbars and against natural and natural/modified habitats. Daily survival rate (DSR) on engineered habitats was significantly higher than on natural or natural modified habitats (log odds: 2.71, 95% CI: 1.20 â 6.08). Predator exclosures around nests did not affect DSR after controlling for the effects of date, nest age, and clutch size. Piping plover juvenile survival to recruitment was negatively related to nesting density on the relatively densely populated engineered sandbars. On the less dense natural sandbars, survival to recruitment was positively correlated with density. Adult survival did not appear to be related to density within our study. Movement within the study area was related also to density. Juveniles from densely populated engineered sandbars were more likely to leave engineered habitat to nest on natural sandbars than were juveniles hatched on less densely populated engineered sandbars. Movements among sandbars by breeding adults suggested that adults preferred engineered habitat. It is possible that juveniles moved to natural habitats because they were unable to compete with adults for the more desirable engineered habitats. Adults and juveniles emigrated from the study area at a higher rate after the 2006 breeding season, a year when water discharge was higher, nesting densities were higher, and reproductive success was lower (as a result of predation) than in the other years. Deterministic modeling suggested that engineered habitat significantly increased population growth. Decreased productivity over time and associated predicted negative population growth suggest that the amount of engineered habitat created was inadequate to sustain population growth, and/or that relatively high water discharge and nesting densities coupled with low reproductive rates and high emigration rates could lead to rapid declines in the plover population. Continued research is needed to determine the effects of these factors on long-term population growth. Our results suggest that habitat creation could be a viable short-term solution to population declines in shorebird populations limited by habitat loss, but high densities and increased predation associated with habitat creation indicate that other, long-term solutions may be required.
Ph. D.

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Lundskog, Måns. « Analysis of 3D design tools for tubing and piping design : Evaluating E3D and CATIA for on-machine tubing and piping design of paper machines using the analytic hierarchy process ». Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik (from 2013), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-72960.

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This thesis covers a degree project for a Bachelor of Science in mechanical engineering degree and is written on behalf of Valmet AB. The purpose of the project is to evaluate and analyse the differences between CATIA and E3D and conclude which of the software is most suitable for on-machine tubing and piping design at Valmet. The tubing and piping modules in CATIA are currently used but is considered somewhat ineffective. E3D is also used at Valmet but in another branch of engineering design, namely field pipe engineering. The analysis is done using the analytic hierarchy process (AHP) which is a multi-criteria decision making (MCDM) methodology developed to aid in complex decision-making problems. The methodology follows a six-step process which results in a prioritized ranking or relative weight of both alternatives with respect to the established criteria and sub-criteria for selection. A total of four main criteria and 12 sub-criteria for the selection of the most suitable CAD system were identified and analysed with the help of relevant personnel in various departments such as engineering, purchasing and management The results of the project conclude that E3D is the preferred CAD system for on-machine tubing and piping at Valmet with regards to the given criteria and sub-criteria. The criteria that favoured E3D most were the availability of the systems, meaning the possibility that Valmet can outsource projects to consultants, as well as the more effective 3D modelling process. However, the results are not heavily one-sided which suggest that more research should be done before a final decision can be taken. The suggested further research includes looking at the in-direct implications of using a new CAD system such as computer updates and the usage of a new PLM system. Moreover, the actual performance of 3D modelling using the two systems is beyond the scope of this thesis and would have to be further researched in another thesis or a pilot case.

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Tan, Hwei-Yang. « Statistical methods for the analysis of corrosion data for integrity assessments ». Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15275.

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In the oil and gas industry, statistical methods have been used for corrosion analysis for various asset systems such as pipelines, storage tanks, and so on. However, few industrial standards and guidelines provide comprehensive stepwise procedures for the usage of statistical approaches for corrosion analysis. For example, the UK HSE (2002) report "Guidelines for the use of statistics for analysis of sample inspection of corrosion" demonstrates how statistical methods can be used to evaluate corrosion samples, but the methods explained in the document are very basic and do not consider risk factors such as pressure, temperature, design, external factors and other factors for the analyses. Furthermore, often the industrial practice that uses linear approximation on localised corrosion such as pitting is considered inappropriate as pitting growth is not uniform. The aim of this research is to develop an approach that models the stochastic behaviour of localised corrosion and demonstrate how the influencing factors can be linked to the corrosion analyses, for predicting the remaining useful life of components in oil and gas plants. This research addresses a challenge in industry practice. Non-destructive testing (NDT) and inspection techniques have improved in recent years making more and more data available to asset operators. However, this means that these data need to be processed to extract meaningful information. Increasing computer power has enabled the use of statistics for such data processing. Statistical software such as R and OpenBUGS is available to users to explore new and pragmatic statistical methods (e.g. regression models and stochastic models) and fully use the available data in the field. In this thesis, we carry out extreme value analysis to determine maximum defect depth of an offshore conductor pipe and simulate the defect depth using geometric Brownian motion in Chapter 2. In Chapter 3, we introduce a Weibull density regression that is based on a gamma transformation proportional hazards model to analyse the corrosion data of piping deadlegs. The density regression model takes multiple influencing factors into account; this model can be used to extrapolate the corrosion density of inaccessible deadlegs with data available from other piping systems. In Chapter 4, we demonstrate how the corrosion prediction models in Chapters 2 and 3 could be used to predict the remaining useful life of these components. Chapter 1 sets the background to the techniques used, and Chapter 5 presents concluding remarks based on the application of the techniques.

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Hickner, Paul V. « Analysis of gene flow among three urban populations of Culex pipiens L. in Indiana ». Muncie, Ind. : Ball State University, 2009. http://cardinalscholar.bsu.edu/651.

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Dominguez, Francisco Ruiz. « Análise estrutural direcionada á redução de espessuras em tubulações industriais ». Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-06042009-172658/.

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Nas plantas industriais dos setores químico e petroquímico observa-se uma grande quantidade de complexas redes de tubulações instaladas, o que se deve basicamente à necessidade de transferir e processar fluídos em diversas condições de pressão e temperatura em suas operações produtivas. Uma indústria petroquímica de médio porte possui entre 3.000 e 15.000 toneladas de tubulações de aço-carbono instaladas, fazendo com que o adequado dimensionamento desse sistema de tubulações adquira grande importância. Este trabalho caracteriza os principais componentes, materiais, condições de projeto e critérios normativos existentes, em especial sob temperaturas elevadas. Realiza uma avaliação comparativa dos métodos de solução estrutural dessas tubulações e analisa criticamente algumas das premissas originais que ainda orientam o seu dimensionamento, visando uma melhor adequação destas. Por fim, juntamente com um estudo de caso, apresenta uma proposta de metodologia de dimensionamento, aplicando o Método dos Elementos Finitos, com o objetivo de aliar mais segurança, otimizar a construção e permitir um projeto mais econômico, diante das grandes quantidades de material envolvidas nessas instalações.
In the chemical and petrochemical plants we can notice a big amount and complexity of pipings installeds, it happens due to the need to transfer and process fluids with differents pressures and temperatures and to get the operational requirements of production. A middle size petrochemical plant has among 3,000 to 15,000 tons of carbon steel pipings assembled so an adjusted sizing of these piping systems is very important. This study presents the main components, materials, design features and existing code procedures, especially under higher temperatures. It makes a comparative valuation about methods of structural solution to pipings and discussing previous concepts applied in the codes to improve these applications. In also, together a case study, presents a proposal of a methodology to sizing of pipings using Finity Element Analyse, with the goal to get a solution more safety, optimized and an economic project, in front of the large quantity of material involved in these installations.

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Zani, Martina. « Analisi numerica della fase di riattivazione di fontanazzi storici lungo le arginature maestre del fiume Po ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.

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L’elaborato si concentra sull’analisi numerica del fenomeno dell’erosione retrogressiva (backward erosion piping) riguardante una sezione fluviale situata lungo la sponda destra del Fiume Po tra Pieve di Saliceto e Boretto in Provincia di Reggio Emilia. La zona circostante è storicamente interessata dal fenomeno dei fontanazzi che si sono riattivati in occasione della piena del Novembre 2000 e 2014, senza tuttavia causare il collasso del corpo arginale. Le analisi sono state effettuate tramite il codice agli elementi finiti PLAXIS. Sono state studiate le conseguenze della piena del Novembre 2018, che non ha portato alla riattivazione del fontanazzo storico. A tal fine si è utilizzato con successo un modello numerico tridimensionale della sezione, creato, calibrato e validato dai ricercatori del DICAM (Università di Bologna). In seguito ci si è proposti di apportare miglioramenti al modello stesso, eseguendo analisi mediante la creazione di modelli numerici bidimensionali di una sezione prossima e simile in stratigrafia e geometria a quella di studio. È stata condotta un’ulteriore procedura di calibrazione del coefficiente di permeabilità dello strato acquifero, confermando la bontà della stima iniziale, effettuata tramite formule empiriche. Inoltre, al fine di migliorare il metodo di stima delle condizioni al contorno da imporre al modello numerico tridimensionale della sezione, è stata studiata la dipendenza dei carichi piezometrici nell’acquifero al variare della lunghezza e dello spessore dello stesso. È stata quindi definita una lunghezza minima da assegnare alla geometria semplificata e bidimensionale, indipendente dallo spessore dell’acquifero, al fine di ricavare con sufficiente accuratezza le condizioni al contorno. Infine è stata effettuata un’ulteriore calibrazione dei coefficienti di permeabilità dei terreni interessati dal fenomeno erosivo riguardanti il modello numerico tridimensionale con lo scopo di renderlo maggiormente aderente alla realtà fisica.

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Bourga, Renaud. « The mechanism of leak-before-break fracture and its application in engineering critical assessment ». Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15289.

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This thesis investigated the different aspects and mechanisms of leak-before-break (LBB) assessment. The main objective was to improve the understanding of the transition between surface and through wall defects. While existing procedures generally idealise the through-wall crack into a rectangular shape, in reality a crack propagates with a shape depending on the loading. Comparison between the related solutions from established procedures have been undertaken. The apparent variation depending on the solutions used in the assessment has been highlighted. Two different methodologies have been employed to investigate the transition of flaw: (i) non-ideal through-wall and (ii) surface-breaking flaw propagation. The first approach consists of numerical models of non-idealised flaws in order to assess the effect on LBB parameters. For the second approach, experiments have been first carried out to visualise the shape of defect growths. To further study surface-breaking flaws, both experimental and numerical studies were performed. Fatigue tests on deeply notched plates with two crack aspect ratios were carried out. Strain evolutions on the back surface were recorded along the axes parallel and perpendicular to the crack. Numerical models have been prepared to investigate a larger scope. Behaviour of growing surface-breaking defects was examined. Based on the work conducted in this research, the major findings can be summarised as follows: - The existing solutions to carry out a LBB assessment using available procedures were reviewed and discussed. For axial flaws, SIF solutions were found similar and in good agreement with FEA values. Reference stress solutions showed significant difference between BS 7910 and API 579-1/ASME FFS-1. When compared to experimental data, API's solutions were able to distinguish between leak and break cases. - Flaw geometry assumption for through-wall crack yet to become idealised did not always reflect the actual behaviour, especially for COA calculation. In this case, FEA can be used as a good predictive tool for LBB to estimate margins when assessing leak rate. - The experiment using metallic specimens showed that high stress/strain on back surface would provide a good estimate of the crack propagation as it approached break-through. This offers a more accurate monitoring mechanism. Strain-mapping devices such as gauges could be used.

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Souza, Claudia Rosana de. « Relativa cortadora : movimento ou apagamento ? » reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/12509.

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Este trabalho é uma análise formal da construção das orações relativas em contextos de sintagmas preposicionais no português oral culto de Porto Alegre em que a preposição não está visível na forma fonética, apesar de a gramática normativa exigi-la. Antes da realização da análise propriamente dita, relembramos a estrutura e a classificação das orações relativas, os pronomes relativos empregados com ou sem preposições e algumas particularidades e inovações dessas estruturas que vêm surgindo no PB, além de apresentar o panorama da gramática gerativa até o modelo de Princípios e Parâmetros, destacando as abordagens gerativas mais relevantes sobre a construção Relativa Cortadora. A análise baseia-se em dados coletados em 24 (vinte e quatro) inquéritos, que correspondem a 24 (vinte e quatro) informantes, registrados no corpus do projeto NURC – Norma Urbana Culta – que totalizam 300 (trezentos) períodos de análise. Seguindo o modelo de pesquisa gerativa – Princípios e Parâmetros –, são levantadas as estratégias de construção das orações padrão e não-padrão, sendo estas classificadas em Relativas Cortadoras e Relativas Copiadoras. Os resultados atestam que a construção não-padrão é utilizada em 69,33% dos casos, sendo 67,00% de Relativa Cortadora e 2,33% de Relativa Copiadora, enquanto que a estratégia padrão é empregada em 30,67% (trinta e três por cento). No uso da estratégia padrão, o emprego do pronome relativo está garantido, sendo resultado de movimento do elemento QU, com fixação de parâmetro [+movQU]; e no emprego das estratégias não-padrão a tendência é o uso da partícula “que”, denominada de “juntor”, correlacionada com o fato de que as orações subordinadas são regidas à principal por meio da conjunção. Neste último caso, QU não resulta de movimento [-movQU], sendo gerado na posição de base e caracterizando que o Português Brasileiro (PB) é uma língua de parâmetro [±movQU].
This work is a formal analysis of the relative clauses’ construction in prepositional sintagms in oral cult Portuguese from Porto Alegre, in which the preposition is not visible in the phonetic form, in spite of the normative grammar requires it. Before accomplishing the analysis, we reminded the construction of the relative clauses, the relative pronouns with or without prepositions and some particularities and innovation of these constructions which are lighting up in BP, besides presenting the generative grammar view until the Principles and Parameters Model, singularizing the most relevant generative subjects about the construction of PP-Chopping. The analysis is based on data collected in 24 enquiries, corresponding to 24 informants registered in the corpus of the NURC project – Urban Cult Norma – which complete 300 periods of analysis. Following the model of generative research – Principles and Parameters –, the strategies standard – Pied-piping – and non-standard clauses´ construction are verified, and classificated in PP-Chopping and Resumptive Pronoun. The results show that the non-standard constructions are used in 69,33% of the cases, being 67,00% of PPChopping and 2,33% of Resumptive Pronouns, while the standard strategy is used in 30,67%. In the usage of the standard strategy, the use of the relative pronouns is assured, being a result of the element WH moviment, with the parameter fixing [+movWH]; while in the nonstandard strategies is tended the usage of “que”, called “juntor”, related to the fact that the subordinate clauses are governed to the main one by the conjuction. In this last case, WH does not result of movement [-movWH], being generated in the base position and characterizing that Brazilian Portuguese is a language of parameter [±movWH].

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Nizamiev, Kamil. « Simulation, Analysis and Design of Systems with Multiple Seismic Support Motion ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1462884476.

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Kim, Mijung. « Expression Analysis of Cytoskeletal and Ribosomal Genes during Adult Diapause in the Northern House Mosquito, Culex pipiens ». The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250174898.

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Pimmarat, Marut. « Finite element analysis of the assembly process for two pipes ». Ohio : Ohio University, 1999. http://www.ohiolink.edu/etd/view.cgi?ohiou1175792842.

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Nguyen, Thuong Anh. « Analyse systématique du concept de comportement linéaire équivalent en ingénierie sismique ». Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1032/document.

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En ingénierie sismique, il est admis que le comportement d’une structure soumise à de forts séismes soit caractérisé par des boucles d’hystérésis qui peuvent être amples ou étroites selon le type de structure impactée. La prise en compte de ce type de comportement non-linéaire dans un calcul temporel présente des difficultés liées à l’identification des paramètres, au coût numérique élevé, au risque de non-convergence. Dans ce contexte, la méthode de linéarisation équivalente, a été introduite en géotechnique dès les années 70. Elle reste peu utilisée dans le domaine des structures malgré les efforts de nombreux auteurs. Ce travail de thèse a pour objet l’étude du comportement linéaire équivalent dans le contexte des méthodes simplifiées d'évaluation de la réponse non-linéaire d'une structure en ingénierie sismique. Nous passons en revue les critères de linéarisation adoptés par les différentes méthodes qui recherchent l’équivalence (1) du déplacement maximum ou (2) de la quantité d’énergie dissipée ou (3) de la force de rappel. Nos analyses montrent que ces trois critères ne sont pas pertinents et/ou efficaces, conduisant à des méthodes peu robustes qui conduisent dans certains cas à des résultats inexplicables. Nous montrons le rôle important, négligé par toutes les méthodes disponibles, du contenu fréquentiel respectif des signaux et du système dans la détermination de la ductilité appelée. Sur cette constatation, nous introduisons une nouvelle méthode de linéarisation équivalente basée sur la fonction de transfert. Nous utilisons cette méthode pour explorer un plan d’expérience numérique dans lequel nous calculons les caractéristiques de fréquence et d’amortissement équivalents en fonction de la ductilité appelée pour différente configurations caractérisées par (a) le rapport entre fréquence de l’oscillateur et fréquence centrale du signal excitateur, (b) la pente d’écrouissage et (c) le modèle de comportement qui varie continument de élastoplastique à endommageant. Nous proposons deux nouvelles approches du comportement linéaire équivalent. La première, visant à améliorer la procédure statique non-linéaire de l’ATC40, utilise la rigidité sécante et le déplacement maximal. Elle fait intervenir une estimation de l’amortissement différente de celle de l’ATC40. Sa pertinence est établie par le fait qu’elle permet d’évaluer avec exactitude le déplacement maximal de systèmes canoniques non-linéaires. La seconde consiste à restituer la dynamique de la réponse d'un oscillateur non-linéaire au travers de la fonction de transfert. Sa pertinence est démontrée au travers des critères d’Anderson, avec notamment un critère relatif au spectre transféré. La détermination du comportement linéaire équivalent par fonction de transfert est validée sur des structures réelles au travers des essais sur voiles en béton armé (SAFE) et sur systèmes des tuyauteries (BARC et EPRI)
In earthquake engineering, it is common that the behaviour of a structure undergoing a strong motion is characterized by wise or narrow hysteresis loops depending on the type of behaviour of the structure. Considering this non-linear behaviour in a transient calculation requires a huge need of resources in terms of calculation time and memory. In this context, the method of equivalent linearization, consisting in the evaluation of the non-linear response of the structure has been introduced by geotechnical engineers In the 1970s. Despite efforts of many authors, this method is still not used in structural field. The goal of this research is to examine the linear equivalent behaviour in the context of the simplified method of evaluating the non-linear response of a structure in earthquake engineering. We review the criteria of equivalence adopted by many methods searching for the equivalence of (1) the maximum of displacement or (2) quantity of dissipated energy or (3) the restore force. Our argumentative analyses carry out that these three criteria are not pertinent and/or efficient. This leads, in some cases, to some unexplained results. We show the important role, which is mostly neglected in existing method, of frequency content while evaluating the ductile demand. Based on this recognition, we introduce a new method of equivalent linearization based on the transfer function. We use this method in order to explore a numerical experimental plan in which we calculate the equivalent characteristics (frequency and damping) versus the ductile demand for different configuration characterized by (a) the ratio between the frequency of the oscillator and the central frequency of the input signal, (b) the hardening and (c) the behaviour which covers the elastoplastic and damaged ones. We propose two new approaches of the linear equivalent behaviour. The first one, aiming to improve the non-linear static procedure of ATC40, use the secant stiffness and the maximal displacement. This approach consists in an estimation of damping which is different to ATC40. Its pertinence is established by evaluating with accuracy the maximal displacement of the canonical non-linear systems. The second approach consists in restitution of the dynamic of the response of a non-linear oscillator by using the transfer function. The pertinence of this proposition is shown through the criteria of Anderson, especially in terms of transferred motion. In this effect, the linear equivalent behaviour based on the transfer function allows to cope the transferred motion through the non-linear oscillator without performing the non-linear transient calculation. The validation of the linear equivalent behaviour based on the transfer function has been examined on real structures through some experimental tests such as the reinforced concrete wall (SAFE) or piping systems (BARC and EPRI)

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Wallace, Catherine. « DISTRIBUTION AND MOLECULAR ANALYSIS OF AVIAN MALARIA VECTORS ON FOUR CENTRAL VIRGINIA PROTHONOTARY WARBLER (PROTONOTARIA CITREA) BREEDING SITES ». VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/172.

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Avian malaria is a devastating disease that has decimated numerous bird species. This study sought to identify the vectors of avian malaria at four central Virginia Prothonotary warbler breeding sites. Twenty one thousand mosquitoes were collected and Culex salinarius, Cx. erraticus, and Cx. pipiens/restuans were found to be the dominant species at these sites. Geographic factors, such as crop land and forest type, were determined to be potential indicators for species abundance variation between sites. Of the mosquitoes collected, ninety one (0.4%) were identified as blood fed. The blood fed mosquitoes were found to have fed on avian, mammalian, amphibian, and reptilian hosts and a 12.1% Plasmodium infection rate. Of the non-blood fed mosquito pools tested, Deep Bottom had the highest rate of infection (10.5%). Of the species tested, Cx. salinarius, Cx. erraticus, and Cx. pipiens/restuans were determined to be the most probable vectors of avian malaria the four sites.

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Alves, Rafael Fabricio. « Estudo experimental do escoamento bifásico líquido gás em golfadas com leve mudança de direção ». Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1708.

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CAPES
Escoamentos bifásicos gás-líquido são muito comuns em aplicações industriais, especialmente nas indústrias de petróleo e gás, química e nuclear. Conforme variam as condições operacionais tais como vazões das fases, dimensão das tubulações e propriedades físicas dos fluidos, ocorrem diferentes configurações geométricas conhecidas como padrões de escoamento. No caso da produção de petróleo, o padrão encontrado com maior frequência é o de golfadas, onde se alternam regiões contínuas de líquido (pistões) e regiões de preponderância gasosa (bolhas alongadas). Em operações de produção de petróleo em águas profundas é comum encontrar cenários onde a tubulação ajusta-se ao relevo do leito marinho, apresentando leves mudanças de direção. Nesse contexto, no presente trabalho é desenvolvido um estudo experimental do escoamento bifásico líquido-gás no padrão golfadas em um duto com leve mudança de direção, composto por um trecho horizontal seguido por um trecho inclinado descendente. São produzidos escoamentos em condições controladas, dos quais são extraídos alguns parâmetros característicos. Os fluidos usados são água e ar e os experimentos são realizados no circuito de testes presente no NUEM (Núcleo de Escoamentos Multifásicos da UTFPR). A extração dos parâmetros é feita através de sensores resistivos, instalados em quatro seções da tubulação. Adicionalmente, duas câmeras de alta taxa de aquisição de imagens são utilizadas. Com os resultados obtidos, avalia-se a influência de uma leve mudança de direção nos parâmetros característicos e na transição do escoamento em golfadas para estratificado na região descendente.
Gas-liquid two-phase flow is very common in industrial applications, especially in the oil and gas, chemical, and nuclear industries. As operating conditions change such as the flow rates of the phases, the pipe diameter and physical properties of the fluids, different configurations called flow patterns take place. In the case of oil production, the most frequent pattern found is slug flow, in which continuous liquid plugs (liquid slugs) and gas-dominated regions (elongated bubbles) alternate. Offshore scenarios where the pipe lies onto the seabed with slight changes of direction are extremely common. With those scenarios and issues in mind, this work presents an experimental study of two-phase gas-liquid slug flows in a duct with a slight change of direction, represented by a horizontal section followed by a downward sloping pipe stretch. The experiments were carried out at NUEM (Núcleo de Escoamentos Multifásicos UTFPR). The flow initiated and developed under controlled conditions and their characteristic parameters were measured with resistive sensors installed at four pipe sections. Two high-speed cameras were also used. With the measured results, it was evaluated the influence of a slight direction change on the slug flow structures and on the transition between slug flow and stratified flow in the downward section.

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Miller, Dominique. « Contribution à l'étude et à la réalisation d'une sonde multi-éléments à courants de Foucault et de l'instrumentation associée, destinée à la détection et la reconstruction tomographique de défauts dans les tubes de générateurs de vapeur ». Cachan, Ecole normale supérieure, 1998. http://www.theses.fr/1998DENS0039.

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Compte-tenu des progrès en matière de modélisation des dispositifs à courants de Foucault, et de résolution des problèmes inverses, on peut espérer pouvoir utiliser bientôt les outils de l'imagerie pour la reconstruction de défauts de pièce métalliques. Encore faut-il disposer d'un capteur approprie, qui échantillonne correctement le champ magnétique et qui soit modélisable. Dans cette thèse, nous présentons les pré déterminations nécessaires à la réalisation d'un capteur multiéléments, dans le cadre du contrôle à grande vitesse de tubes de générateurs de vapeurs. Cela conduit en la conception d'une sonde de type microsystème, avec détecteurs sur silicium et électronique de conditionnement embarquée. Par ailleurs, la reconstruction tomographique étant une opération coûteuse en temps de calcul, et elle ne doit être appliquée que sur des zones suspectes. Nous proposons un pré traitement rapide et efficace, base sur l'analyse en composantes principales pour détecter de telles zones, malgré un rapport signal à bruit souvent très mauvais. L'ensemble sonde/pré traitement donne des résultats très satisfaisant en termes de détection, et doit permettre par la suite une reconstruction tomographique des défauts.

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STIACCINI, ISACCO. « PhD Thesis - Stiaccini ». Doctoral thesis, 2015. http://hdl.handle.net/2158/994827.

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Modellazione ibrida tempo-frequenza per analisi di compressori alternativi e rispettivi impianti. L'approccio consente di valutare l'interazione tra la macchina e l'impianto. Al fine di modellare in dettaglio le cavità complesse della macchina, è stata definita ed applicata una procedura di caratterizzazione basata su risultati di simulazioni realizzate con FEM acustico. La metodologia di modellazione è stata applicata ad un compressore per cicli frigoriferi a CO2 e verificata attraverso il confronto con dati sperimentali. An accurate and effective numerical modelling of the reciprocating compressors in the preliminary phase of design can assure reliability in the operating conditions and avoid failures. In most cases, the geometric complexity of some elements interacting with the compressor, such as plena and mufflers, makes both the fluid-dynamic 1D and acoustic lumped parameters modelling of the system unable to assure the required detail level necessary for the design process. For this reason, an acoustic numerical characterization is the most suitable way for the analysis of the response of geometrically complex elements. In order to analyze the thermodynamic and acoustic performance of a compressor for refrigerating application, a hybrid numerical model is developed that allows to carry out simultaneously the time-domain analysis of the compressor thermodynamic cycle and the frequency-domain acoustic analysis of the pipelines system. An acoustic characterization method based on acoustic FEM simulation results was also defined to model in detail the compressor cavities with complex geometries (i.e. compressor plena). The results of the compressor hybrid model with both acoustic FEM characterization and acoustic lumped elements were compared with experimental measurements. Moreover, a comparison between the developed hybrid model and the stand-alone compressor model with constant pressure boundary conditions was carried out. The advantages in using the acoustic FEM characterization of the complex geometry elements were highlighted.

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Chung, Chao-Hsuan, et 鍾昭瑄. « Design and Analysis of Hydraulic Piping System Paint Circulation Piping System of Automotive Shop ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/55137339700605607340.

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碩士
中原大學
機械工程研究所
94
Abstract This paper is to design and analyze the pipe system for fluid transfer. By using paint circulation system in automotive paint shop as the example, we can analyze the pressure and flow volume of multi-outlet piping network. Base on the law of the conservation of mass, the law of the conservation of energy and Dracy Weisbach Formula. We calculate the friction and pressure loss caused by pipe material and accessory. In further, we develop software to design and analyze the pipe network of paint circulation system. We design and establish the software of piping system to check which are different between reality and simulation. After adjust influence factor, the software get modify numbers to match user requirement. According to the experience, we find dynamic loss from pipe accessory is the key factor to affect flow volume and pressure. The reason is construction quality varied. Therefore, the construction quality must be controlled properly to make sure fluid transfer uniformly.

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Chin-Hsien, Kao, et 高志先. « Design and analysis of hydrolic piping system ». Thesis, 2003. http://ndltd.ncl.edu.tw/handle/65032129580808640910.

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碩士
國防大學中正理工學院
兵器系統工程研究所
91
Piping system design mainly divides calculating head loss of conduits between choosing motive power. This study use hypothetical fuel supply system to proceed to the flow rate experiment, to estimate unknown flow rate of circuit by iteration, and to simulate the piping system by HyPneu. We compare to experimentation, estimation, and simulation each other, and we analysis the relationship of every conduit design methods to know the discrepancy piping design by software between real situation. We can understand to the result of piping system simulating by software is close to the one of circuit iteration and has just a little difference to the one of experiment, and we can get important reference basis of piping design. On the other hand, we use pump characteristic curve and system impendence curve to solve working point of the smallest pump efficiency. We discuss the efficiency of pump parallel connection to obtain the parameter of piping system design, too.

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Lin, Kung-Mo, et 林昆模. « Analysis of Complex Piping System Including Power Sources ». Thesis, 2002. http://ndltd.ncl.edu.tw/handle/88083369163548526234.

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Chung-Jen, Chang, et 張仲忍. « The Efficiency Analysis for Hot Water Piping in Building ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/75388503195744191191.

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碩士
正修科技大學
電機工程研究所
102
Water supply pipeline was the most basic systems in buildings. Especially hot water supply piping of the building material, in the discussion and analysis on the energy saving is lacking. In Taiwan, along with the emphasis on green building and energy-saving idea promotion, making hot water supply pipeline in the green building materials and energy-saving efficiency analysis has become a very worthwhile discussion topics. In this paper, various types of pipeline construction and now commonly used in buildings of all kinds of hot water pipes, respectively, from the construction method and engineering analysis of the rate of benefit as a whole. Respectively for hospitals, hotels, business hotels, office buildings and residential buildings and other types of buildings, for pipes of different materials for statistical analysis method, economic benefit and its carbon footprint. Each material pipe was summarized by the results of superior, inferior; through case analysis and comparison of the results are applicable to all types of buildings with better overall efficiency of pipe, can provide developers with a design unit in the selection of references on the pipe.

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Shih, Kuan-Ju, et 施冠如. « Stress Analysis and Fatigue Inspection of Class 1 Piping System ». Thesis, 2011. http://ndltd.ncl.edu.tw/handle/20622455621899049447.

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Cassa, Amanda Marilu. « A numerical investigation into the behaviour of leak openings in pipes under pressure ». Thesis, 2008. http://hdl.handle.net/10210/464.

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South Africa is a water scarce country where a large number of people still are not provided with adequate water. This project will help to manage water resources in a sustainable manner that will benefit the country as a whole. This study concentrated on the behaviour of pipe materials with leak openings under different pressure conditions. The stress distribution throughout a pipe is known due to the pressures within the pipe i.e. the longitudinal and circumferential stresses as well as the working pressure of the pipe, however when a leak opening such as a hole or crack appears in the pipe the stress distribution around these openings change. It is the effect of this stress distribution that this study addressed. The effect of stresses around these leak openings may provide some knowledge as to how and when the pipes will fail completely as well as help in explaining the leakage exponents within pipes. Using the method of Finite Element Analysis (FEA) the project aimed to find the relationship between the pressure in the pipe and the behaviour of the leak openings for different leak types. The different leak openings investigated were: a circular hole, a longitudinal crack and a circumferential crack. This study used finite element analysis to understand what happens to a pipe when pressure is applied within the pipe and the pipe has a leak opening e.g. a small hole, a longitudinal crack or a circumferential crack in it. The materials studied were uPVC, steel, cast iron and fibre-cement. The main conclusions drawn from this study were that when a pipe has a circular hole in it the leakage exponent does not differ from the theoretical value of 0.5. With the longitudinal cracks it was found that regardless of whether there are longitudinal stresses in the pipe or not the leakage exponent is the same: and these exponents vary significantly from the theoretical value of 0.5 and can be in the order of 0.87, 0.82, 0.75, 0.55 for a 60 mm long crack in an uPVC, steel, cast iron and fibre-cement pipe respectively. With the circumferential cracks however, there were significant differences in exponents due to the longitudinal and lack of longitudinal stress. For the case when the pipe has the longitudinal stresses the exponents were significantly larger than 0.5. The exponents were in the order of 1.15, 1.02, 0.95, and 0.64 for a 150 mm long crack of uPVC, steel, cast iron and fibre-cement respectively. If there is no longitudinal stress then the exponents were smaller than 0.5 and tended to close the crack along the circumference. The exponents were 0.45, 0.47, 0.46, and 0.49 for a 150 mm crack of uPVC, steel, cast iron and fibre-cement respectively.
Prof. J.E. van Zyl

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34

Eichenberg, Thomas William. « Numerical analysis of condensation induced water-hammer in horizontal piping systems ». Thesis, 1990. http://hdl.handle.net/1957/38056.

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Condensation Induced Water-Hammer, CIWH, has been an historical problem for the nuclear power industry over the past 2 decades. It has caused damage to plant systems, and considerable anguish to plant operators. This thesis has embarked on an attempt to characterize the fluid motion, heat transfer, mixing, and stability of a horizontal, stratified flow of steam over subcooled water. A literature review was conducted to determine the state of numerical and analytical methods which have been applied to this problem. The result of the review has led to the implementation of new analytical interfacial stability models. Information from the review has also led to the development of correlations for wave frequency and amplitude on the phase interface. A numerical model has been developed to estimate the temperature profile on the phase interface. Also, the model will construct, by use of the above correlations, an estimate of the interface wave structure. This wave structure is then evaluated against a non-linear model for interface stability to determine the onset of slug formation. The numerical model has been used to evaluate two known CIWH events. The results indicate that the onset of slug formation is necessary, but not sufficient, to ensure a water-hammer event. The results imply that there is the possibility that once a slug has formed, it may break up before a trapped steam void can fully collapse. The model also indicates that CIWH in steam generator, feedwater nozzle sections is not due to the formation of slug on an unstable phase interface. Rather, CIWH may occur when the liquid level inside of the feedwater nozzle is above the top of the feedring, thus creating an isolated steam pocket. The rapid condensation of the trapped steam in the causes CIWH. This particular result implies that it may be possible to completely avoid CIWH in the feedwater nozzle altogether.
Graduation date: 1991

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35

Hu, Pei-Wen, et 胡佩文. « Seismic Fragility Analysis of Fire Protection Sprinkler Piping Systems in Hospital ». Thesis, 2015. http://ndltd.ncl.edu.tw/handle/89996154439471740524.

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碩士
國立臺灣大學
土木工程學研究所
103
According to the concept of the performance design, the damage caused by earthquake will not necessary result in the damage to the structure. However, the earthquake disaster will cause the non-structural instruments break. The break of the fire protection sprinkler system will result in death, the working error of the medical equipment and even the expense on repairing the equipment. Therefore, evaluating the seismic design of the fire protection sprinkler system to the performance design level is extraordinary. The common failures of the fire protection sprinkler system are from the damage of the threaded joint leading to the leakage of the pipe water, or the collapse of the ceiling. The research expecting to conduct the non-structural fragility curves in the hospital. And take NTU hospital Yunlin branch as an example to demonstrate a fragility analysis procedure. The abstract of each chapter in the research are: 1. The ambient vibration test in the case hospital: Use the velocimeters to conduct the ambient vibration test to clarify the characteristics of the structure. 2. The simplified numerical model of the fire protection sprinkler system in the case hospital: Use the numerical analysis software SAP2000 v.15 to build the piping system in the hospital. And suggest the parameter of the threaded joint, partition wall and the ceiling. 3. The fragility analysis of the fire protection sprinkler system in the case hospital: Conduct the seismic fragility curves of the fire sprinkler components in the hospital and predict the damage situation under Chia-Shen earthquake. Finally, suggest the fragility analysis procedure.

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Wen, Jih-Chuan, et 溫日川. « The Study of Technical Competency Analysis for Technicians in Piping Occupations ». Thesis, 2002. http://ndltd.ncl.edu.tw/handle/04011326716068177378.

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碩士
國立臺北科技大學
技術及職業教育研究所
90
Abstract The purpose of this study was to develop the contents of technical competency for technicians of piping occupations in Taiwan; furthermore, to examine the difficulty, importance level and the using frequency of the technical competency. The methods applied in this study were documental analysis, modified DACUM of competency analysis approaches. First, analyzed the technical competency of technicians and obtain “technical competency profile of piping”. Secondly, used questionnaire survey to obtain the various opinions from technicians and teachers of piping; and then, with the results utilized percents, mean, interval estimation, spearman rank correlation to analyze the difficulty, importance level and using frequency of the technical competency. The conclusion of this study is as follows: 1. “Technical competency profile of piping” contains three jobs: water supply piping; industrial piping and gas piping. Water supply piping includes 12 duties and 43 tasks; industrial piping includes eight duties and 36 tasks; gas piping includes 12 duties and 43 tasks. 2. With the results of the statistics of the importance level and using frequency, the three jobs’ tasks were categorized to “Must-prepared technical competency” and “Should-prepared technical competency”. That is 32 “Must-prepared technical competency” and 11 “Should-prepared technical competency” for water supply piping; 20 “Must-prepared technical competency” and 16 “Should-prepared technical competency” for industrial piping; 28 “Must prepared technical competency and 14 “Should-prepared technical competency for gas piping. 3. According to the difficulty of technique and “Must-prepared technical competency” and “Should-prepared technical competency”, set the reference tables of “Instruction Sequence” and “priority of required teaching facilities obtaining sequence” for the three jobs respectively. Apart from providing the revision of curriculum and instructional design for employee training in piping of occupations, vocational training and the section of piping in vocational high school, this study could also be referred to skill-testing specification, occupational classification system.

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37

Chang, Yung-Yu, et 張永昱. « Thermal hazard analysis for PAA catalyzed by various piping metal ions ». Thesis, 2017. http://ndltd.ncl.edu.tw/handle/4r9umc.

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38

« Development of response spectra for the seismic structural analysis of piping systems ». Tese, MAXWELL, 1998. http://www.maxwell.lambda.ele.puc-rio.br/cgi-bin/db2www/PRG_0991.D2W/SHOW?Cont=1469:pt&Mat=&Sys=&Nr=&Fun=&CdLinPrg=pt.

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39

« Evaluation of some design methods for modal spectral seismic analysis of piping systems ». Tese, MAXWELL, 1998. http://www.maxwell.lambda.ele.puc-rio.br/cgi-bin/db2www/PRG_0991.D2W/SHOW?Cont=1414:pt&Mat=&Sys=&Nr=&Fun=&CdLinPrg=pt.

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40

Parayitham, Sashidhar K. Lissenden Cliff Jesse. « Penetration power of ultrasonic guided waves for piping and well casing integrity analysis ». 2008. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-3634/index.html.

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41

Lee, Ping-Hung, et 李秉鴻. « Improvement on Guided Wave Inspection in Complex Piping Geometries by Wavelet Transform Analysis ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/72078533809969245758.

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博士
國立中山大學
機械與機電工程學系研究所
98
The safety of pipelines distributed in the infrastructure of many industries has become very important since the industrial revolution. The guided ultrasonic wave technique can provide the possibility for rapid screening in long pipelines with corrosion. Especially the torsional mode T(0,1) of guided waves has been used in the cases of the pipe in the hidden region substantially. The ability of evaluating the inaccessible areas of the pipe makes the guided ultrasonic wave technique sit high on the roster of non-destructive testing tool for pipe inspection. However, the problem arises when attempting to detect the corrosions at the welded support bracket or under the bitumen coating on the pipe. The signal reflected from the corrosion will be covered by a large signal induced by the welded support or attenuated by the bitumen coating seriously. Therefore, the effects of welded support and bitumen coating on the T(0,1) mode are investigated by the experimental and the simulative methods. The continuous wavelet transform analysis is the signal processing method to extract the hidden signal of corrosion in this dissertation. There are five test pipes in the experiments. The response of the normal welded support is studied on the #1 test pipe. The #2 test pipe is used for attenuation investigation. The reflected signals of the features on the #3, #4, and #5 test pipes are measured and processed by continuous wavelet transform during defect detection process. In addition, the linear hexahedron elements are used to build the finite element models of the 6-inch steel pipe with support bracket and the pipe with bitumen coating. It is found that the effects of support bracket on the reflection comprise mode conversion, delayed appearance, trailing echoes, and frequency dependent behavior. When the T(0,1) mode impinges on to the support bracket, it will convert into the A0 mode inside the support due to the circumferential disturbance on the pipe surface. The reflection of the support bracket is identified as three parts formed by the direct echo, delayed echo and the trailing echo. The constructive interference of the A0 mode reflecting from the boundaries inside the support causes that the reflection spectrum shows two maxima peak at around 20-22 kHz (frequency regime of 0.0) and 32-34 kHz (frequency regime of 4.0) from both the experimental and simulated results. For the bitumen coating, the data collected from the welds and defects under the bitumen coating on the #2 test pipe show the attenuation effect on guided wave propagation and the difficulty of minor corrosion detection. In the finite element model of coated pipe, the results of predicted attenuation curves of T(0,1) mode indicate that the attenuation effect on guided wave propagation is aggravated with the increased value of the thickness, density or damping factor of the coated layer. Especially, in the case of 5-mm, the predicted attenuation curve shows a maximum point. Before this point, the attenuation increases with the operating frequency. For long range pipe inspection, it is the best way to avoid choosing the operating frequency around the corresponding frequency of the point. The measured data of corrosion affected by the welded support or the coated bitumen layer was processed by continuous wavelet transform to form a time-frequency analysis. The corrosion signals were identified in the contour map of the wavelet coefficient successfully. The understanding of the guided wave propagation on the pipe welded with support or pipe coated with bitumen is helpful to interpret the reflected signals. The use of continuous wavelet transform on signal processing techniques can improve the ability of defect detection on pipe with complex geometries.

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42

Post, van der Burg Max. « Pseudorandom walks in ecological analysis capturing uncertainty for better estimation and decision making / ». 2008. http://proquest.umi.com/pqdweb?did=1633768271&sid=1&Fmt=2&clientId=14215&RQT=309&VName=PQD.

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Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008.
Title from title screen (site viewed Feb. 17, 2009). PDF text: x, 145 p. : ill. (some col.) ; 2 Mb. UMI publication number: AAT 3331439. Includes bibliographical references. Also available in microfilm and microfiche formats.

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43

Liu, Yan-Fang, et 劉嚴方. « Numerical Analysis and Experimental Verification of Residual Heat Removal Piping System in Power Plants ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/08674539255886723627.

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碩士
國立臺灣大學
機械工程學研究所
102
The Residual Heat Removal (RHR) piping system is one of the most important systems in a nuclear power plant. It is used to provide emergency cooling water to protect the reactor core from high temperature damage during severe accidents. Its strength has therefore to be guaranteed. In order to reduce the accidental risk of power plants, especially owing to strong earthquakes, it is essential to investigate the mechanics behavior of the RHR piping system. This study is divided into two parts. In the first part, both the component test and system test are carried out to investigate the failure modes and mechanics behavior of the RHR piping system. In addition, to confirm the piping system meets the requirements of ASME design code when it is subjected to large earthquakes. In the second part, finite element method is employed for numerical analysis. The numerical models for both the flange joints and the piping system were established and verified according to the experimental results. Furthermore, a simplified model of the flange joints is proposed in this study. By comparing numerical results with the experimental results, it is concluded that all models proposed in this study predict the experimental results reasonably well. In particular, comparing to the original model of the flange joint, the simplified model effectively reduces 70% of the calculation time.

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44

Lyu, Yo-Xuen, et 呂宥勳. « Mechanics Analysis and Experimental Verification of Flange Joints in Piping Systems of Power Plant ». Thesis, 2016. http://ndltd.ncl.edu.tw/handle/65869676765453510932.

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碩士
國立臺灣大學
機械工程學研究所
104
Piping systems are used to carry gas and liquid medium, the pipes are often connected to each other by welding or flange joints in the same or different directions with fittings and valves, building up the piping systems. To make sure the piping system working properly, we should avoid the failure modes such as damage、leakage and so on happened, especially for those in the connected joints. Piping systems are usually used to transport the steam driving the turbine or the water in the cooling units. The Residual Heat Removal (RHR) piping system is one of the most important systems in a power plant, composed of heat exchangers 、valves and primary the piping systems. When the power plant is under emergency condition, the systems mentioned will supply the emergency cooling water to make sure the core components won’t be damaged due to high temperature. In order to avoid the failure modes such as damage、leakage, and so on happened, we should make sure the pipelines especially for those within the joint are strong enough to function normally under seismic condition. In this thesis, we study the loosening mechanism in the case of RHR-C loop in power plant, and focus on how the plastic deformation on the gasket will lead to loosening of the clamping force of the bolts. By setting the zero clamping force as the index of failure, discuss if the allowable moment of flange joints defined by ASME B&PV Code is applicable for this case. This study is divided into two parts. In the first part, we found that the leakage phenomenon happened in the quasi static test of RHR pipeline. Then, a simplified component test is going to examine all the components in the flange joint. After finding that the gasket is the most critical component by a comparison test, we study the mechanism between the deformation and loading on it. After then, by taking the experimental data into the FEM input and creating the numerical model of those pipeline in experiments. By comparing the FEM results and the experiment data measured, we can make sure that the deformation behavior of the gasket accounts for the loosening in clamping force of the bolts. We build the piping system taking the gasket behavior into account, and setting both static and dynamic analysis. By comparing the results of the analysis and experiment data, it is concluded that the analysis is fitting reasonably well. By the end of the study, we’ll make an analysis to predict if the ASME piping PV code is suitable for this case.

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45

Cassa, Amanda Marilu. « A numerical investigation into the behaviour of cracks in uPVC pipes under pressure ». Thesis, 2012. http://hdl.handle.net/10210/5255.

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D.Ing.
This study is a numerical investigation into the behaviour of cracks in uPVC pipes under pressure. This study is a continuation of a Masters dissertation which showed that leakage exponents vary significantly from the theoretical orifice exponent of 0.5 for cracks in pipes for different materials. This study looks at the behaviour of cracks in more detail and specifically with regard to the parameters of the pipe and crack. Using Finite Element Analysis the relationship between the pressure head and the leak area in pipes with longitudinal, spiral and circumferential cracks was investigated. It was found that the longitudinal, spiral and circumferential crack areas increase linearly with pressure. The slope of this linear relationship depends on various parameters, including loading state, pipe dimensions and pipe material properties. The effect that the individual pipe parameters had on the pressure-area slope was investigated. These parameters included the material properties of the pipe (Young’s modulus, Poisson’s ratio and longitudinal stress), the geometry of the pipe (internal diameter and wall thickness) as well as the geometry of the crack (length of the crack and the width of the crack). Once the effect of the pressure-area slope m is known, the link between the conventional leakage exponent N1 and the pressure-area slope m was further investigated and the effect of each parameter on the leakage exponent N1 was found. Using various data techniques the above data was combined and processed to find mathematical relationships that give reasonable descriptions of the pressure-area slopes of longitudinal, spiral and circumferential cracks. Once these equations for the pressure-area slopes were determined it was possible to obtain three new relationships for leakage from longitudinal, spiral and circumferential cracks.

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46

You, Jang-Shyong, et 游章雄. « Study on reliability analysis and preventive maintenance policies for piping system of nuclear power plant ». Thesis, 2002. http://ndltd.ncl.edu.tw/handle/07832721407466638338.

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博士
國立臺灣大學
機械工程學研究所
90
A probabilistic failure analysis model for the prediction of life and failure probability of a piping system or its components is proposed in the present study. The model incorporates probability and statistical theories into material failure criteria by considering parameters that can affect the propagation of the crack as random and evaluate the failure probability of the pipe. By comparing the results of some numerical examples with those from running the well-known PRAISE Code, it indicates that the proposed model possess a rather good prediction capacity, and in the degree of analysis and calculation time. Based on similar theories, this simpler model can be extended to make a more realistic analysis of a nuclear pipe weld having known initial crack size. The result of the above probabilistic failure analysis model can also be used in combination with that of the probabilistic risk assessment model. Risk-based preventive maintenance policies for piping systems of either boiling water reactors or pressurized water reactors can therefore be developed. The major concept is to quantify the likely risks existing in the piping systems in order to distinguish their individual importance according to the risk significances of the systems. Based on the degree of importance, the extent and period of plant maintenance can be adjusted rationally. The results of the numerical analysis suggest that the risk-based preventive maintenance policy developed in the present study does have the dual advantages of reducing maintenance cost and still preserving the required plant safety.

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47

Po-HaoLin et 林柏豪. « Seismic Response and Fragility Analysis of Residual Heat Removal Piping System for Nuclear Power Plant ». Thesis, 2019. http://ndltd.ncl.edu.tw/handle/6c5t43.

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碩士
國立成功大學
土木工程學系
107
The residual heat removal (RHR) is one of the systems of the emergency core cooling system (ECCS). When the loss of coolant accident (LOCA) happens, the high pressure water injection system cannot maintain the water level in reactor and will activate low pressure water injection system - residual heat removal system (RHR) in order to supply the cooling water for reactor to maintain the water level. The purpose is to remove the residual heat generated by the reactor core and avoid the hazard induced due to high core temperature. According to the final safety analysis report of the sample nuclear power plant (NPP), in the accident sequence that has the greatest contribution to inducing reactor core meltdown, the ac-independent water addition system (ACIWA) is the main cause. In addition, in the ACIWA system, risk achievement worth (RAW) of rupture of the RHR piping is the highest among all components in NPP. Therefore, this dissertation takes the RHR piping in the ACIWA system of the sample NPP as the research object. Firstly, the finite element software ABAQUS is used to analyze the flange joints in the RHR piping, which are more complicated in analysis procedure and may cause liquid leakage in the piping. Then the results of 4-point bending test are used to verify the correctness of the flange joint model. This joint is further used in the RHR piping system shaking table model, and the correctness of the model is verified by shaking table test. The ultimate goal of this dissertation is to establish the fragility curve of the RHR system and discuss the variables supposed to be considered and how to select them in the fragility analysis method proposed by Reed and Kennedy. Combined with the numerical model analysis results, the fragility curve is finally drawn, which serves as the reference for seismic probabilistic risk assessment (SPRA).. The analysis results show that the RHR piping system in the sample NPP has good seismic performance, and the probability of damage caused by earthquakes is very low, which is not a key equipment affecting the safety of sample NPP.

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48

Yeh, Chang-Chen, et 葉昶辰. « Seismic Evaluation and Simplified Methodology of Fragility Analysis for Fire Protection Sprinkler Piping Systems in Hospitals ». Thesis, 2016. http://ndltd.ncl.edu.tw/handle/31350506785875833237.

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碩士
國立臺灣大學
土木工程學研究所
104
Based on the popularization of performance design concepts for structures of critical building (e.g. hospitals and schools) in recent years, non-structural seismic damages (e.g. sprinkler piping systems) are more common than structural ones. Fire protection sprinkler systems plays important roles to prevent fire disasters and ensure occupant safety.However, failure of fire protection sprinkler system will result in not only threat to occupant safety but also the shut down of medical function and relating expense on repairing. Therefore, an accurate assessment method to evaluate the seismic ability of fire protection system is necessary. The common seismic failures resulted from fire protection sprinkler systems are impact damages of ceiling boards, leakages of 1″threaded joints and breaks of hangers. In order to understand the seismic ability of components mentioned above, this research propose several assessment methods and take NTU Hospital Yunlin branch as an example to conduct the fragility analysis of the component in fire protection sprinkler system. The main results are briefly described below: 1. Performance design method for piping systems: Referring to FEMA P58[1], only when building structures are judged as reparable will assessment of sprinkler piping be meaningful. Therefore, in this study, seismic performance of sprinkler piping will be evaluated only when the structure is reparable. 2. In order to investigate the effects of characteristics of input motion on the fragility analysis of piping systems, a nonlinear numerical model was established using MIDAS software for the RC structure of the example hospital building. 3. A detailed numerical model of the horizontal sprinkler piping system was established using SAP2000 software to simulate nonlinear behaviors of hangers and the nonlinear relationship between piping and ceiling systems or partition walls (Method A). The fragility parameters of three seismic performance of piping system were than obtained through incremental dynamic analyses. 4. According to the dynamic characteristics of the sprinkler piping system, a partial detailed analysis method (Method B) and a simplified assessment method (Method C) are proposed in this study. Comparing to the result of Method A, the one of Method B is more conservative but through a more efficient process. Method C is provided to be engineers an additional choice that a rapid but rough judgment in the seismic performances of sprinkler piping systems can be made based on in-situ observations and the floor response spectrum. The fragility results of Method C are very close to those of Method B in terms of median values but are with quite low divergence.

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49

Veeramany, Arun. « Multi-State Reliability Analysis of Nuclear Power Plant Systems ». Thesis, 2012. http://hdl.handle.net/10012/6862.

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The probabilistic safety assessment of engineering systems involving high-consequence low-probability events is stochastic in nature due to uncertainties inherent in time to an event. The event could be a failure, repair, maintenance or degradation associated with system ageing. Accurate reliability prediction accounting for these uncertainties is a precursor to considerably good risk assessment model. Stochastic Markov reliability models have been constructed to quantify basic events in a static fault tree analysis as part of the safety assessment process. The models assume that a system transits through various states and that the time spent in a state is statistically random. The system failure probability estimates of these models assuming constant transition rate are extensively utilized in the industry to obtain failure frequency of catastrophic events. An example is core damage frequency in a nuclear power plant where the initiating event is loss of cooling system. However, the assumption of constant state transition rates for analysis of safety critical systems is debatable due to the fact that these rates do not properly account for variability in the time to an event. An ill-consequence of such an assumption is conservative reliability prediction leading to addition of unnecessary redundancies in modified versions of prototype designs, excess spare inventory and an expensive maintenance policy with shorter maintenance intervals. The reason for this discrepancy is that a constant transition rate is always associated with an exponential distribution for the time spent in a state. The subject matter of this thesis is to develop sophisticated mathematical models to improve predictive capabilities that accurately represent reliability of an engineering system. The generalization of the Markov process called the semi-Markov process is a well known stochastic process, yet it is not well explored in the reliability analysis of nuclear power plant systems. The continuous-time, discrete-state semi-Markov process model is a stochastic process model that describes the state transitions through a system of integral equations which can be solved using the trapezoidal rule. The primary objective is to determine the probability of being in each state. This process model ensures that time spent in the states can be represented by a suitable non-exponential distribution thus capturing the variability in the time to event. When exponential distribution is assumed for all the state transitions, the model reduces to the standard Markov model. This thesis illustrates the proposed concepts using basic examples and then develops advanced case studies for nuclear cooling systems, piping systems, digital instrumentation and control (I&C) systems, fire modelling and system maintenance. The first case study on nuclear component cooling water system (NCCW) shows that the proposed technique can be used to solve a fault tree involving redundant repairable components to yield initiating event probability quantifying the loss of cooling system. The time-to-failure of the pump train is assumed to be a Weibull distribution and the resulting system failure probability is validated using a Monte Carlo simulation of the corresponding reliability block diagram. Nuclear piping systems develop flaws, leaks and ruptures due to various underlying damage mechanisms. This thesis presents a general model for evaluating rupture frequencies of such repairable piping systems. The proposed model is able to incorporate the effect of aging related degradation of piping systems. Time dependent rupture frequencies are computed and the influence of inspection intervals on the piping rupture probability is investigated. There is an increasing interest worldwide in the installation of digital instrumentation and control systems in nuclear power plants. The main feedwater valve (MFV) controller system is used for regulating the water level in a steam generator. An existing Markov model in the literature is extended to a semi-Markov model to accurately predict the controller system reliability. The proposed model considers variability in the time to output from the computer to the controller with intrinsic software and mechanical failures. State-of-the-art time-to-flashover fire models used in the nuclear industry are either based on conservative analytical equations or computationally intensive simulation models. The proposed semi-Markov based case study describes an innovative fire growth model that allows prediction of fire development and containment including time to flashover. The model considers variability in time when transiting from one stage of the fire to the other. The proposed model is a reusable framework that can be of importance to product design engineers and fire safety regulators. Operational unavailability is at risk of being over-estimated because of assuming a constant degradation rate in a slowly ageing system. In the last case study, it is justified that variability in time to degradation has a remarkable effect on the choice of an effective maintenance policy. The proposed model is able to accurately predict the optimal maintenance interval assuming a non-exponential time to degradation. Further, the model reduces to a binary state Markov model equivalent to a classic probabilistic risk assessment model if the degradation and maintenance states are eliminated. In summary, variability in time to an event is not properly captured in existing Markov type reliability models though they are stochastic and account for uncertainties. The proposed semi-Markov process models are easy to implement, faster than intensive simulations and accurately model the reliability of engineering systems.

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Wu, Shu-Ling, et 吳淑玲. « The Defect Factor Analysis by Using FMEA and QFD – A Study of the Straight Pipe Prefabrication of the Piping Construction for the Case Companyconstruction for the Case Company ». Thesis, 2013. http://ndltd.ncl.edu.tw/handle/58cpg6.

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碩士
國立虎尾科技大學
工業工程與管理研究所
101
This research integrates FMEA and QFD and applies them into the straight pipe prefabrication of the piping construction for the case company. This is to investigate the possible failure modes and customer’s requirements for the pipe prefabrication process. The outcome from the appropriately designed questionnaire will be summarized, calculated for the RPN of FMEA and quality weighted index of QFD and adjusted to the process appraisal weights. The importance of these failure modes then can be prioritizing by the value of the process appraisal weights and resolve accordingly. The result can help the pipe prefabrication personnel discover and resolve the defect factors in the pipe prefabrication process in advance, reduce the loss, and improve the construction quality. Case company should actively adopt FMEA and QFD to ensure the quality of piping construction and meet the requirements of customers. After the adoption, case company should have the results of reducing the costs of equipment, materials, and manpower costs, reducing the complaints from the customers, increasing the passing rate of the straight pipe prefabrication X ray inspection, shortening the duration of the construction, increasing satisfaction with the quality of construction, and increasing the opportunity to obtain future construction contract. Other than the use of FMEA and QFD, future research may use other multi-attribute decision making method. Through different calculation methods, the outcome may be different form the one obtained from the FMEA and QFD and thus make it more objective and reliable.

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