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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Measurement and verification of industrial DSM projects / Walter Booysen

Booysen, Walter January 2014 (has links)
Energy cost-reduction projects implemented on complex industrial systems present several challenges. The involvement of multiple project stakeholders associated with programmes such as demand side management (DSM) further increases potential risks. The process of determining project impacts is especially important due to the direct financial impact on stakeholders. A good understanding of the independent measurement and verification (M&V) process is therefore vital to ensure an unbiased process. A review of existing M&V frameworks and guidelines found that M&V protocols and templates are well developed and widely implemented. Unfortunately, the official literature provides little guidance on the practical M&V of industrial DSM projects. This prompted a detailed literature analysis of numerous publications to ascertain the industry norm. The diverse results obtained are categorised, normalised and graphically presented to highlight shortcomings in present M&V processes. This thesis develops several practical methodologies and guidelines to address the needs highlighted by the literature analysis. Three chapters are dedicated to the development and verification of these solutions. The first entails the evaluation of data quality with the aim of producing an accurate and error-free dataset. The second develops, evaluates and ultimately selects a baseline model representative of normal system operations. The final chapter presents project performance and uses existing methods to monitor system changes and project performance over the long term. The new methodologies are designed to simplify the practical implementation of different processes. Results are graphically presented thereby enabling quick and intuitive evaluation whilst adhering to present M&V requirements. This makes the M&V process accessible to all stakeholders and enables the transparent development and improvement of all processes. The practical application of the new methodologies is verified by using 25 industrial case studies. The results obtained are validated using data obtained from independent third parties. This proves the functionality of the methodologies and highlights trends that can be evaluated in future studies. The new methodologies improve the accuracy and efficiency of the evaluation process. The potential annual impacts amount to R27 million for DSM stakeholders and R19 million for M&V teams. The extrapolation of these results indicates a massive potential impact on international projects. These results, albeit estimates, confirm the significant contribution of the new methodologies. I would like to officially thank Prof. Eddie Mathews and Prof. Marius Kleingeld for granting me the opportunity to work under their guidance. Thanks to all the staff at the Centre for Research and Continued Engineering Development Pretoria, who created the ideal environment for working and learning. I would also like to thank TEMM International (Pty) Ltd for the bursary without which my studies would not be possible. Finally, I would like to thank my fellow students as well as all the industry professionals whom I had the privilege of working with. On a personal note, I would like to thank God for making all things possible. Thank you my dearest family, friends and all who had a profound impact on my life. For you I quote Paulo Coelho’s Alchemist: “And, when you want something, all the universe conspires in helping you to achieve it.”. Thank you for your love, sacrifice, support and being part of my universe. I dedicate this work to you. / PhD (Electrical Engineering), North-West University, Potchefstroom Campus, 2014
2

Measurement and verification of industrial DSM projects / Walter Booysen

Booysen, Walter January 2014 (has links)
Energy cost-reduction projects implemented on complex industrial systems present several challenges. The involvement of multiple project stakeholders associated with programmes such as demand side management (DSM) further increases potential risks. The process of determining project impacts is especially important due to the direct financial impact on stakeholders. A good understanding of the independent measurement and verification (M&V) process is therefore vital to ensure an unbiased process. A review of existing M&V frameworks and guidelines found that M&V protocols and templates are well developed and widely implemented. Unfortunately, the official literature provides little guidance on the practical M&V of industrial DSM projects. This prompted a detailed literature analysis of numerous publications to ascertain the industry norm. The diverse results obtained are categorised, normalised and graphically presented to highlight shortcomings in present M&V processes. This thesis develops several practical methodologies and guidelines to address the needs highlighted by the literature analysis. Three chapters are dedicated to the development and verification of these solutions. The first entails the evaluation of data quality with the aim of producing an accurate and error-free dataset. The second develops, evaluates and ultimately selects a baseline model representative of normal system operations. The final chapter presents project performance and uses existing methods to monitor system changes and project performance over the long term. The new methodologies are designed to simplify the practical implementation of different processes. Results are graphically presented thereby enabling quick and intuitive evaluation whilst adhering to present M&V requirements. This makes the M&V process accessible to all stakeholders and enables the transparent development and improvement of all processes. The practical application of the new methodologies is verified by using 25 industrial case studies. The results obtained are validated using data obtained from independent third parties. This proves the functionality of the methodologies and highlights trends that can be evaluated in future studies. The new methodologies improve the accuracy and efficiency of the evaluation process. The potential annual impacts amount to R27 million for DSM stakeholders and R19 million for M&V teams. The extrapolation of these results indicates a massive potential impact on international projects. These results, albeit estimates, confirm the significant contribution of the new methodologies. I would like to officially thank Prof. Eddie Mathews and Prof. Marius Kleingeld for granting me the opportunity to work under their guidance. Thanks to all the staff at the Centre for Research and Continued Engineering Development Pretoria, who created the ideal environment for working and learning. I would also like to thank TEMM International (Pty) Ltd for the bursary without which my studies would not be possible. Finally, I would like to thank my fellow students as well as all the industry professionals whom I had the privilege of working with. On a personal note, I would like to thank God for making all things possible. Thank you my dearest family, friends and all who had a profound impact on my life. For you I quote Paulo Coelho’s Alchemist: “And, when you want something, all the universe conspires in helping you to achieve it.”. Thank you for your love, sacrifice, support and being part of my universe. I dedicate this work to you. / PhD (Electrical Engineering), North-West University, Potchefstroom Campus, 2014
3

Investigating the Relationship between Stride Interval Dynamics, the Energy Cost of Walking and Physical Activity Levels in a Pediatric Population

Ellis, Denine 31 December 2010 (has links)
The strength of time-dependent correlations known as stride interval (SI) dynamics have been proposed as an indicator of neurologically healthy gait. Most recently, it has been hypothesized that these dynamics may be necessary for gait efficiency although the supporting evidence to date is limited. To gain a better understanding of this relationship, this study investigated stride interval dynamics, the energy cost of walking, and physical activity in a pediatric population. The findings indicate that differences in energy cost are not reflected in the stride interval dynamics of able-bodied children. Interestingly, increasing physical activity levels were associated with decreasing variance in stride interval dynamics between subjects, though this finding only approached significance (p=0.054). Lastly, this study found that stride interval dynamics in children as young as nine years were comparable to stride interval dynamics found in healthy young adults.
4

Investigating the Relationship between Stride Interval Dynamics, the Energy Cost of Walking and Physical Activity Levels in a Pediatric Population

Ellis, Denine 31 December 2010 (has links)
The strength of time-dependent correlations known as stride interval (SI) dynamics have been proposed as an indicator of neurologically healthy gait. Most recently, it has been hypothesized that these dynamics may be necessary for gait efficiency although the supporting evidence to date is limited. To gain a better understanding of this relationship, this study investigated stride interval dynamics, the energy cost of walking, and physical activity in a pediatric population. The findings indicate that differences in energy cost are not reflected in the stride interval dynamics of able-bodied children. Interestingly, increasing physical activity levels were associated with decreasing variance in stride interval dynamics between subjects, though this finding only approached significance (p=0.054). Lastly, this study found that stride interval dynamics in children as young as nine years were comparable to stride interval dynamics found in healthy young adults.
5

Article: Reducing the electricity cost of a three-pipe water pumping system : a case study using software / White Rautenbach

Rautenbach, John White January 2004 (has links)
Efficient control is often the most cost-effective option to improve on the running cost of a Three-Pipe Water Pumping System. However, the effect of changing the control strategy (i.e. on energy consumption) is usually difficult to predict. To obtain this information more easily, a new simulation tool, QUICKcontrol, was developed. This new tool was used to investigate the energy cost savings potential in a Three-Pipe Water Pumping System. The influence of pump scheduling, dam level set points, control parameters and different combinations thereof was investigated. The simulation models were firstly verified with measurements obtained from the existing system to confirm their accuracy for realistic control retrofit simulations. With the aid of the integrated simulation tool it was possible to predict savings of R 195'000 per year with an average 3.8 MW of load shifted. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.
6

Article: Reducing the electricity cost of a three-pipe water pumping system : a case study using software / White Rautenbach

Rautenbach, John White January 2004 (has links)
Efficient control is often the most cost-effective option to improve on the running cost of a Three-Pipe Water Pumping System. However, the effect of changing the control strategy (i.e. on energy consumption) is usually difficult to predict. To obtain this information more easily, a new simulation tool, QUICKcontrol, was developed. This new tool was used to investigate the energy cost savings potential in a Three-Pipe Water Pumping System. The influence of pump scheduling, dam level set points, control parameters and different combinations thereof was investigated. The simulation models were firstly verified with measurements obtained from the existing system to confirm their accuracy for realistic control retrofit simulations. With the aid of the integrated simulation tool it was possible to predict savings of R 195'000 per year with an average 3.8 MW of load shifted. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.
7

Investigating energy expenditure in wheelchair athletes

Croft, Louise January 2012 (has links)
The increased participation in elite wheelchair sport has provided the need to investigate the physiological requirements of wheelchair sporting competition and daily wheelchair propulsion. However, from a nutritional perspective, guidelines that have been established from the able-bodied population tend to be used by the practitioners working in disability sport and it is not known whether this information is directly transferable to the wheelchair athlete. Wheelchair sport is complex and athletes differ with respect to their sports classification based on factors relating to disability and functional capacity. Therefore, if nutritional guidance is required to optimise performance then information regarding energy expenditure (EE) in the wheelchair sports population becomes important for specific feedback. The aim of this thesis was to investigate EE in wheelchair athletes. The results from Chapter 3 found resting energy expenditure (REE) in tetraplegic athletes to be lower than that calculated using predictive equations derived from an ablebodied cohort. However, paraplegic athletes showed comparable values to those which were predicted, suggesting these equations may be of use in paraplegic athletes. Chapter 4 extended this work and found similarities in the REE of the two aforementioned cohorts. This could have been due to the similarities that were found in their total-body fat free mass (FFM). The results from Chapter 5 showed EE reduced after both a short 36 minute exposure of wheelchair propulsion and after 3 weeks of wheelchair propulsion practice in novice wheelchair users. Temporal parameters improved after the practice period, suggesting there is an association between EE and propulsion technique. Chapter 6 extended these findings with results confirming that experienced wheelchair users expended significantly less energy during wheelchair propulsion than novice individuals who had up to 3 weeks practice. It is clear that EE of daily wheelchair ambulation should not be a generic value and different levels of experience must be considered so that the nutritional needs can be tailored accordingly. Chapters 7 and 8 examined the physiological demands of elite competitive wheelchair basketball players in relation to the International Wheelchair Basketball Federation (IWBF) classification categories and identified differences in the physiological demands and physiological fitness of wheelchair basketball and tennis players. These results found that IWBF Class 3 - 4.5 (high point) players expended more energy per hour during competition than those with a lower classification (IWBF Class 1 - 2.5). However, when actual playing time was considered the low classification group showed a similar EE to the higher classification group. Furthermore, wheelchair basketball players had a higher EE per hour than wheelchair tennis players during elite competition. However, the wheelchair tennis players spent a significantly longer duration on court resulting in similar EE during a typical competition within each sport. This suggests nutritional advice should be tailored both to the duration of competitive play (where EE may be similar between sports (basketball vs. tennis)); and to training (where athletes with a higher functional capacity may have higher EE). This thesis revealed several important physiological considerations to appreciate when investigating the EE of wheelchair sportsmen and women. Findings would suggest that type of disability, wheelchair propulsion experience and sport classification are all important considerations for the accurate assessment of EE in this cohort of athletes.
8

L'influence allométrique dans les relations entre économie de course, rendement mécanique et performance chez des athlètes de longue distance : efficience métabolique et prédiction de la performance en course a pied de longue distance / Influence of the allometric scale on the relationships between running economy, mechanical efficiency and performance in long distance runners : running efficiency and long-distance performance prediction

Peikriszwili Tartaruga, Marcus 11 December 2013 (has links)
Le but de cette thèse était d'analyser la relation entre l’économie de course à pied (ECO) et l'efficiencemécanique (Eff) dans la performance des coureurs spécialistes en moyenne et longue distance, utilisantdes modèles allométriques. Basé dans les résultats de trois études originales, nous avons conclu quel’échelle allométrique peut améliorer la relation entre ECO et performance dans la course à pied demoyenne et longue distance, principalement en coureurs amateurs, pour raison morpho-fonctionnelles.Également, pour cette même population, des travaux mécaniques, principalement le externe, peut êtreconsidérées comme prédicteurs de la performance de la course à pied de sujets spécialistes en longuedistance, et un exposant allométrique peut améliorer cette prédiction. En ce qui concerne à l’Eff, lesrésultats ont montré que cette variable est, aussi, une important variable de prédiction de laperformance. Toutefois, quand appliqué des exposant allométriques, il n'y avait aucune améliorationdans cette prédiction, principalement en coureurs de haut niveau. Les résultats ont montré, aussi, quepour le calcul de l’Eff, la contribution de la dépense énergétique anaérobie est important, parce que,contrairement, les résultats peuvent être surestimés. En général, lorsque l’objectif est prédit laperformance des coureurs amateurs de moyenne ou de longue distance, à travers des puissancesmétaboliques ou mécaniques, est suggéré d'adopter un exposant allométrique spécifique du groupeétudié. Toutefois, lorsque cette prédiction est réalisée avec la utilisation de l’Eff en un groupe decoureurs de haut niveau, l’échelle allométrique n’est pas indiquée. / The aim of this thesis was to use allometric models to analyze the relationship that running economy(ECO) and mechanical efficiency (Ef) have on the performance of middle- and long-distance runners.Based on the results of three original studies, we concluded that allometric scaling can improve therelationship between ECO and performance in recreational middle- and long-distance runners, mainlydue to morphofunctional aspects. Similarly, the mechanical works, especially the external mechanicalwork, may be considered to be predictive of running performance and a specific allometric exponentcan improve these predictions. The results also showed that Ef is an important predictor of theperformance of long-distance runners. However, when the specific allometric exponents were applied,there was no improvement in the prediction of this performance. The results also showed that it isimportant to consider the contribution of anaerobic energy expenditure when calculating Ef, becauseotherwise the results may be overestimated, as already reported in other studies. In general, when theobjective is to predict the performance of middle- or long-distance runners through metabolic ormechanical powers, it is useful to adopt a specific allometric exponent of the group investigated.However, when this prediction is performed considering the Ef, particularly in high-performance longdistancerunners, the allometric application is not necessary.
9

A influência de diferentes sistemas de amortecimento do calçado esportivo na economia de corrida e no desempenho / The influence of different cushioning systems of sports shoes on running economy and performance

Dinato, Roberto Casanova 20 April 2018 (has links)
O objetivo geral do estudo foi investigar o impacto do calçado minimalista e dos calçados esportivos com entressola de termoplástico Poliuretano expandido (TPE) sobre os parâmetros fisiológicos e o desempenho durante a corrida. O estudo 1 comparou o calçado minimalista e o calçado com TPE na economia de corrida (EC) e o desempenho. Doze corredores homens foram submetidos aos seguintes testes: a) teste progressivo até a exaustão para caracterização da amostra; b) duas corridas contrarrelógio de 3 km em uma pista de atletismo de 400 m e ao final dos testes responderam uma avaliação de conforto. c) quatro testes de corrida submáxima de 6 minutos em uma esteira para determinar a EC, o custo de oxigênio (CTO2) e a componente vertical da força reação do solo. Houve uma maior EC (~2,4%) (P = 0,01), aumento do primeiro pico (~15,8%) (P = 0,01) e diminuição da taxa de propulsão (~15,9%) (P = 0,01) no TPE em comparação ao calçado minimalista. No entanto, não houve diferenças significativas entre TPE e minimalistas para CTO2 (P = 0,61) e desempenho total de corrida (P = 0,61). Essas descobertas revelaram que o calçado TPE produz uma EC maior e uma taxa de propulsão mais baixa em comparação com calçados minimalistas, mas essas melhorias não foram acompanhadas por mudanças no CTO2 e, consequentemente, no desempenho na corrida. O estudo 2 comparou 3 calçados com diferenças percentuais de TPE inserido na entressola. As principais diferenças metodológicas foram a análise da EMG e o teste de corrida de 10 km. Não houve diferença estatística entre os calçados para as variáveis EC, componente vertical da força reação do solo (FRS), EMG e desempenho. A análise de regressão revelou que 96% do desempenho em uma prova de 10 km podem ser explicados pelas variáveis altura do arco e controle médio-lateral para o modelo de calçado TPE 55%. Nenhuma variável biomecânica analisada neste estudo foi capaz de identificar alguma diferença que pudesse estabelecer uma diferença entre os calçados que repercutisse em desempenho ou EC. Os resultados práticos dos estudos revelaram que correr com calçado TPE melhora a EC em comparação ao calçado minimalista. No entanto, a melhora na EC não se refletiu em desempenho no teste de corrida de 3 km. Diferentes porcentagens de TPE inseridos na entressola do calçado não produziram diferenças na EC e desempenho em uma prova de 10km. Desta forma, ainda não é possível dizer qual calçado é capaz de reduzir o tempo gasto em uma prova de corrida de curta ou longa duração / The overall objective of the study was to investigate the impact of minimalist footwear and sports shoes with midsole thermoplastic expanded polyurethane (TPE) on physiological parameters and performance during running. Study 1 compared minimalist shoes and TPE shoes in running economy and performance. Twelve male distance runners performed the following tests: a) a maximal incremental test to characterize the sample; b) two 3-km time-trials on an outdoor 400 m track and at the end of tests answered an evaluation of comfort. c) four 6-min submaximal running tests on a treadmill to determine the RE, energetic cost (CTO2) of 3 km running time-trial and ground reaction force parameters. The athletes performed the sub-maximal running tests and 3-km time trials using the TPE and minimalist shoes. There was a higher RE (~2.4%) (P = 0.01), increased first peak (~15.8%) (P = 0.01), and decrease push-off rate (~15.9%) (P = 0.01) in TPU compared with minimalist shoes. However, there were not significant differences TPU and minimalist shoes for CTO2 (P = 0.61) and overall running performance (P = 0.61). These findings revealed that TPU produces a higher RE and a lower push-off rate when compared to minimalist shoes, but these improvements were not accompanied by changes in CTO2 and, consequently in running performance. Study 2 compared 3 shoes with differences percentage TPE inserted in the midsole. The main methodological differences were the EMG analysis and the 10 km running time-trial. There was no statistical difference between shoes for the EC, vertical component of ground reaction force and EMG. Regression analysis revealed that 96% of the performance in a 10 km running time-trial can be explained by the variable height of the arch and medial-lateral control to the shoe model TPE 55%. No biomechanical variable analyzed in this study was able to identify any differences that could establish a difference between the shoes that had repercussions on RE or performance. The practical results of the studies have shown that running with TPE improves the RE compared to minimalist shoes. However, the improvement in RE was not reflected in performance in the 3-km running time-trial. Different percentages of TPE inserted in the shoe midsole did not produce differences in RE and performance in a 10km running time-trial. Thus, it is not possible to tell which shoes is able to reduce the time spent on a short or long running race
10

Contribution à la robustification des techniques de contrôle MPC appliquées aux systèmes électriques / Contribution to the Robusti cation of Model Predictive Control Techniques for Electrical System Applications

Sawma, Jean 30 November 2016 (has links)
La commande prédictive de type Model Predictive Control (MPC) s’est imposée au fil du temps dans de nombreux domaines industriels. Elle permet en effet d’optimiser avec succès les performances du système contrôlé tout en respectant de nombreuses contraintes propres à l’application visée. Cependant, l’utilisation de la commande MPC dans les domaines de la commande de moteurs et de générateurs demeure problématique. En effet, ces applications à forte dynamique imposent de choisir de faibles périodes d’échantillonnage, or, ce type d’algorithme demande de résoudre pour chaque période d’échantillonnage un problème d’optimisation complexe. Cette difficulté est renforcée car le champ applicatif visé portant sur les applications embarquées aéronautiques où la vitesse de base des machines électriques est très élevée, de même que leur fréquence d’alimentation. De plus, du fait que les systèmes étudiés sont embarqués, il est également très important de minimiser les pertes énergétiques de l’ensemble convertisseur-machine. Dans ce contexte la commande prédictive par approche MPC peut être d’un grand intérêt. De plus, ce type d’application intègre des contraintes supplémentaires liées à l’environnement sévère dans lequel évoluent ces systèmes, contraintes additionnelles de fiabilité qu’il faut bien sûr ajouter dans l’algorithme de commande prédictif. La conséquence immédiate sera de renforcer la complexité des algorithmes et donc rendre plus difficile l’implantation en temps réel. Cependant, les gains attendus en termes de performance et de fiabilité sont importants. Le sujet proposé demande ainsi dans une première partie, de synthétiser une loi de commande prédictive d’un actionneur synchrone aéronautique. Une mission type sera choisie et l’optimisation portera à la fois sur le niveau des performances du contrôle que la minimisation de la dépense énergétique. Par ailleurs, une étude de robustesse sera menée qui prendra en compte l’impact de l’environnement de l’actionneur. L’aspect robustesse sera ainsi intégré à l’étude de la commande. La seconde partie du travail portera sur le portage de l’algorithme sur cible FPGA. Une attention toute particulière sera apportée à la minimisation du temps de calcul sans détérioration des performances, le tout sous contrainte de place. Il faudra privilégier une architecture de type Système-sur-Puce qui allie la flexibilité d’un ou plusieurs cœurs processeurs et de modules matériels dédiés à l’accélération de certaines parties critiques du traitement. / Nowadays, Model Predictive Control (MPC) has emerged in many industrial fields. It allows the optimization of the controlled drive performances while respecting a number of constraints specific to the application. However, the use of MPC in the fields of motors and generators control remains problematic. Indeed, these highly dynamic applications require small sampling periods. However, these types of algorithms necessitate the resolution of complex optimization problems at each sampling period. These difficulties are reinforced in our case as the chosen field is the aeronautical embedded applications where the drive speed, as well as the frequency, is important. In addition, as the systems are embedded ones, it is important to minimize the overall energy losses of the inverter-drive system. In this context, the Model Predictive Control can be of great interest. Moreover, this type of applications integrates additional constraints related to the harsh environment in which the systems evolve, such as the reliability, which must be added in the predictive control algorithm. The immediate consequence of these constraints results in an increase of the complexity of the algorithms and therefore it becomes more difficult to implement in real time. However, the expected gains in performance and reliability are important. The proposed subject requires in the first part, to synthesize a predictive control law of an aeronautical synchronous drive. A typical mission will be selected and the optimization will be performed on both the performance level of the control and the minimization of the energy cost. Furthermore, a robustness study is to be conducted that takes into account the environmental impact of the motor drive. The second part will be on the implementation of the algorithm on FPGA target. Particular attention will be paid to minimizing the computational time without any degradation in the performances. Focus will be upon architectures of the type System-on-chip (SoC) that combines the flexibility of one or more processor cores and dedicated hardware modules for accelerating critical parts of the treatment.

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