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Many different numeric models have been created to address a variety of hydraulic and hydrologic engineering applications. Each utilizes formulations and numeric methods to represent processes such as contaminant transport, coastal circulation, and watershed runoff. Although one process may be adequately represented by a model, this does not guarantee that another process will be represented even if that process is similar. For example, a model that computes subcritical flow does not necessarily compute supercritical flow. Selecting an appropriate numeric model for a situation is a prerequisite to obtaining accurate results. Current policies and resources do not provide adequate guidance in the model selection process. Available resources range from approved lists to guidelines for performing calculations to technical documentation of candidate numeric models. Many of these resources are available only from the developers of the numeric models. They focus on strengths with little or no mention of weaknesses or limitations. For this reason, engineers must make a selection based on publicity and/or familiarity rather than capability, often resulting in inappropriate application, frustration, and/or incorrect results. A comprehensive selection tool to aid engineers needs to test model capabilities by comparing model output with analytical solutions, laboratory tests, and physical case studies. The first step in building such a tool involves gathering and categorizing robust data the can be used for such model comparisons. A repository has been designed for this purpose, created, and made available to the engineering community. This repository can be found at http://verification.aquaveo.com. This allows engineers and regulators to store studies with assigned characteristics, as well as search and access studies based on a desired set of characteristics. Studies with characteristics similar to a desired project can help identify appropriate numeric models.

Orientador: Jorge Roberto Pimentel / Banca: Marcos Antonio Sanches Vieira / Banca: Ricardo Egydio de Carvalho / Resumo: O resfriamento de produtos agrícolas, em ambientes com atmosfera controlada, é uma das técnicas que tem sido utilizada por produtores e indústrias do setor, sendo importante se ter informações sobre a influência de parâmetros que atuam durante o processo. Neste trabalho, foi desenvolvido um modelo numérico unidimensional usando-se um método explícito de aproximação das derivadas de equações diferenciais por diferenças finitas, para solucionar a equação da condução de calor em sólidos com alto teor de água e de formato cilíndrico, que estejam submetidos a um fluxo de ar resfriado. Utilizando o modelo, simulou-se a influência de variáveis físicas e geométricas na distribuição das temperaturas radiais em cilindros hipotéticos, obtendo-se resultados coerentes com o comportamento previsto para tal situação. Foram feitas medidas experimentais das temperaturas em diferentes localizações radiais em alguns vegetais com formato aproximadamente cilíndrico e, os resultados dessas medidas, comparados com as previsões numéricas, revelando boa concordância dentro da faixa do erro experimental. / Abstract: Cooling in atmosphere controlled environment is one of the methods used in the food preservation and processing industry. For best process improvement information, for example, concerning the influence of different parameters on the internal temperature values are of interest. The present work deals with a simple numeric model developed using a explicit finite-differences scheme for solve the one-dimensional cylindrical transient heat equation. The equation is solved with a field temperature inicial condition, simetry center boundary condition and a pure convection surface boundary condition after normalizing the equation system. A FORTRAN program was develop to solve the resulting matricial system to obtain the transient radial temperature distribution as a function of convective heat coefficient, Fourier number, thermal diffusivity and Biot number. The experimental setup consisted of a retangular duct througt witch cooled air circulated by a blower. Inside the duct fresh approximated cylindrical shapped samples of food products have they radial temperature measured in four different location using iron-constantan thermocouples. The results show that there is a good a agreement between the experimentally measured temperature values and that computed using numeric model. / Mestre

This work presents a new hybrid symbolic-numeric method for fast and accurate evaluation of multiple integrals, effective both in high dimensions and with high accuracy. In two dimensions, the thesis presents an adaptive two-phase algorithm for double integration of continuous functions over general regions using Frederick W. Chapman's recently developed Geddes series expansions to approximate the integrand. These results are extended to higher dimensions using a novel Deconstruction/Approximation/Reconstruction Technique (DART), which facilitates the dimensional reduction of families of integrands with special structure over hyperrectangular regions. The thesis describes a Maple implementation of these new methods and presents empirical results and conclusions from extensive testing. Various alternatives for implementation are discussed, and the new methods are compared with existing numerical and symbolic methods for multiple integration. The thesis concludes that for some frequently encountered families of integrands, DART breaks the curse of dimensionality that afflicts numerical integration.

This work presents a new hybrid symbolic-numeric method for fast and accurate evaluation of multiple integrals, effective both in high dimensions and with high accuracy. In two dimensions, the thesis presents an adaptive two-phase algorithm for double integration of continuous functions over general regions using Frederick W. Chapman's recently developed Geddes series expansions to approximate the integrand. These results are extended to higher dimensions using a novel Deconstruction/Approximation/Reconstruction Technique (DART), which facilitates the dimensional reduction of families of integrands with special structure over hyperrectangular regions. The thesis describes a Maple implementation of these new methods and presents empirical results and conclusions from extensive testing. Various alternatives for implementation are discussed, and the new methods are compared with existing numerical and symbolic methods for multiple integration. The thesis concludes that for some frequently encountered families of integrands, DART breaks the curse of dimensionality that afflicts numerical integration.

Water hammer represents a complex hydraulic phenomenon with significant consequences on the proper functioning and safety of operation for pipe and conduit systems. The complexity and intricate physics of water hammer translated into significant difficulties associated firstly, with finding a proper solution for understanding the mechanism of its occurrence and, secondly, relating to proposing technically and economically viable design methods and devices that would help reduce and mitigate water hammer effects. In this context, the present thesis deals with the numerical modeling of the transient behaviour of water pipe segments. Following an extensive literature review of the state-of-the-art on the water hammer mechanisms and past work on experimental, analytical and numerical analysis of this phenomenon, a three dimensional numerical model of the water hammer in a pipe which considers the fluid-structure interaction (FSI) is developed using a Finite Element Method – Finite Volume Method (FEM-FVM) technique. Structural and fluid computational results based on rapid and slow gate closure scenarios are compared with existing closed-form solutions of the water hammer. A parametric study is also performed on a simply supported pipe segment to determine the influence of various design parameter. A systematic sensitivity analysis was conducted and a ranking mechanism was established for the importance of each parameter on the fluid fields and structural response. A first comparative analysis is conducted on horizontally and vertically bent elevated pipe segments to quantify the influence of the bend angle on the results. A second comparative analysis is performed on a horizontally bent segment buried in soil to determine the influence of the pipe interaction with the soil on the response. It is observed that the thickness, span, initial velocity and bend angle had a significant impact on the pressure and structural response. The presence of soil was observed to have a significant benefit in decreasing the von-Mises stresses.

Made available in DSpace on 2014-06-11T19:25:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-07-30Bitstream added on 2014-06-13T20:53:33Z : No. of bitstreams: 1 massoni_pr_me_rcla.pdf: 268207 bytes, checksum: 6e94a8d273c83e316e9da0bdfcaea8a1 (MD5) / O resfriamento de produtos agrícolas, em ambientes com atmosfera controlada, é uma das técnicas que tem sido utilizada por produtores e indústrias do setor, sendo importante se ter informações sobre a influência de parâmetros que atuam durante o processo. Neste trabalho, foi desenvolvido um modelo numérico unidimensional usando-se um método explícito de aproximação das derivadas de equações diferenciais por diferenças finitas, para solucionar a equação da condução de calor em sólidos com alto teor de água e de formato cilíndrico, que estejam submetidos a um fluxo de ar resfriado. Utilizando o modelo, simulou-se a influência de variáveis físicas e geométricas na distribuição das temperaturas radiais em cilindros hipotéticos, obtendo-se resultados coerentes com o comportamento previsto para tal situação. Foram feitas medidas experimentais das temperaturas em diferentes localizações radiais em alguns vegetais com formato aproximadamente cilíndrico e, os resultados dessas medidas, comparados com as previsões numéricas, revelando boa concordância dentro da faixa do erro experimental. / Cooling in atmosphere controlled environment is one of the methods used in the food preservation and processing industry. For best process improvement information, for example, concerning the influence of different parameters on the internal temperature values are of interest. The present work deals with a simple numeric model developed using a explicit finite-differences scheme for solve the one-dimensional cylindrical transient heat equation. The equation is solved with a field temperature inicial condition, simetry center boundary condition and a pure convection surface boundary condition after normalizing the equation system. A FORTRAN program was develop to solve the resulting matricial system to obtain the transient radial temperature distribution as a function of convective heat coefficient, Fourier number, thermal diffusivity and Biot number. The experimental setup consisted of a retangular duct througt witch cooled air circulated by a blower. Inside the duct fresh approximated cylindrical shapped samples of food products have they radial temperature measured in four different location using iron-constantan thermocouples. The results show that there is a good a agreement between the experimentally measured temperature values and that computed using numeric model.

Water hammer represents a complex hydraulic phenomenon with significant consequences on the proper functioning and safety of operation for pipe and conduit systems. The complexity and intricate physics of water hammer translated into significant difficulties associated firstly, with finding a proper solution for understanding the mechanism of its occurrence and, secondly, relating to proposing technically and economically viable design methods and devices that would help reduce and mitigate water hammer effects. In this context, the present thesis deals with the numerical modeling of the transient behaviour of water pipe segments. Following an extensive literature review of the state-of-the-art on the water hammer mechanisms and past work on experimental, analytical and numerical analysis of this phenomenon, a three dimensional numerical model of the water hammer in a pipe which considers the fluid-structure interaction (FSI) is developed using a Finite Element Method – Finite Volume Method (FEM-FVM) technique. Structural and fluid computational results based on rapid and slow gate closure scenarios are compared with existing closed-form solutions of the water hammer. A parametric study is also performed on a simply supported pipe segment to determine the influence of various design parameter. A systematic sensitivity analysis was conducted and a ranking mechanism was established for the importance of each parameter on the fluid fields and structural response. A first comparative analysis is conducted on horizontally and vertically bent elevated pipe segments to quantify the influence of the bend angle on the results. A second comparative analysis is performed on a horizontally bent segment buried in soil to determine the influence of the pipe interaction with the soil on the response. It is observed that the thickness, span, initial velocity and bend angle had a significant impact on the pressure and structural response. The presence of soil was observed to have a significant benefit in decreasing the von-Mises stresses.

Bakgrund: Smärtintensitet är en viktig del i smärtbedömningen som utförs av hälso- och sjukvårdspersonal. Om smärtintensitet inte bedöms på ett bra sätt riskerar det att leda till en otillräcklig smärtbehandling. Ett av de mest validerade instrumenten för att ta reda på patientens självskattade smärtintensitet är Numeric Rating Scale (NRS). Dagens forskning visar att det finns brister i arbetet med smärtskattningsskalor och behandlingen av smärta inom vården. Syfte: Att beskriva betydelsen av ett värde på Numeric Rating Scale och hur en förändring av värdet ska tolkas, ur ett patientperspektiv. Metod: En litteraturstudie baserad på 8 studier med kvantitativ ansats. Resultat: Resultatet presenterades under tre huvudkategorier och två underkategorier, dessa tre huvudkategorierna var: Vad det numeriska värdet har för innebörd i patientens NRS-skattning, Vad en förändring i patientens NRS skattning innebär samt vad NRS-värdet säger om patientens önskan av smärtlindring. Konklusion: Ett värde på NRS ger inte hela bilden av hur en patient upplever sin smärta. Ett värde på NRS kan vara en god indikator på smärtnärvaro hos patienten. När ett värde på NRS förändras säger det mest om patientens upplevelse när förändringen tolkas procentuellt. Det kan vara problematiskt för sjuksköterskan att bedöma en patients behov av åtgärd på endast ett NRS värde då dess betydelse kan variera stort mellan patienter. Utifrån detta bör hälso-och sjukvårdspersonal alltid föra en dialog om vad ett värde och en förändring på NRS betyder för patienten.

While fatigue is a common daily phenomenon, the exact relationship between perception of effort and fatigue is still unknown. Existing tools for assessing perception of effort are effectively limited to whole body exercise, while current methods for assessing voluntary activation are painful and not feasible for clinical application. The main aims of this thesis were to evaluate existing methodologies for their appropriateness in assessing perception of effort and voluntary activation following isolated muscle function testing, and to examine the relationship between subjective perception of effort and objective changes in the healthy motor control system. The implementation of reliable and valid assessment tools in clinical practice may enable clarification of the pathogenesis of many neurological conditions that have chronic fatigue as a key feature. Four studies of within-subjects repeated measures design have been conducted. Sixtynine healthy volunteers were recruited among staff and students of Brunel University. Magnetic stimulation was tested as a valid alternative to electrical stimulation in the conventional single-pulse Twitch Interpolation Technique. The 0–10 Numeric Rating Scale (NRS) was also tested for its reliability and validity in assessing the perception of effort during isometric exercise of elbow flexors. The changes of perception of effort following a submaximal elbow flexion fatiguing task, as well as following transcranial direct current stimulation (tDCS) over the motor cortex were also tested. The main findings showed significant differences between peripheral and magnetic stimulation in conventional single-pulse Twitch Interpolation Technique. The 0–10 NRS demonstrated linear properties and reported excellent test-retest reliability and good concurrent criterion validity in recording perception of effort under repeated isometric contractions of elbow flexors. Ten minutes of a submaximal intermittent isometric fatiguing exercise produced a significant elevation in rating of perceived effort, which was associated with central and peripheral neurophysiological changes of the motor control system. In contrast, perception of effort did not change significantly following 10 minutes of tDCS. The major findings of this thesis suggest the 0–10 NRS is a valid and reliable scale for rating perception of effort in healthy individuals. Further testing of the scale on patients is needed to establish its validity in clinical settings. Additionally, the findings indicate a substantial role of perception of effort in the voluntary motor control system. However, further research towards revealing the underlying mechanisms of perceived effort regulation in both health and disease is required.