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Eficiência da braçada no nado crawl : atualização do estado da arte / The arm stroke efficiency in front crawl swimming : updating the state of the artSilveira, Ricardo Peterson January 2016 (has links)
O tópico principal desta tese de doutorado foi a efficiência da braçada no nado crawl. A tese foi composta e dividida em três artigos originais, com o objetivo de: (1) investigar as relações existentes entre a eficiência da braçada e a potência de membros superiores na determinação da velocidade máxima do nado crawl, (2) estimar os efeitos da pernada na velocidade de nado e no cálculo da eficiência da braçada no nado crawl, e (3) comparar os diferentes métodos utilizados para estimativa da eficiência da braçada e identificar os principais preditores biofísicos da velocidade máxima em 200 m crawl utilizando apenas os braços. Diferentes métodos foram utilizados para quantificar a eficiência da braçada, como o modelo da “roda de pás” (estudos 1, 2, e 3), a razão entre a velocidade de nado e a velocidade deslocamento da mão (estudo 3), e o método utilizando o MAD System (estudo 3). A contribuição da pernada foi estimada individualmente, considerando as diferenças de velocidade de nado para uma determinada frequência gestual, em diferentes intensidades. Os componentes úteis e não-úteis para a potência mecânica total exercida pela braçada foram obtidos por meio de protocolos fora d’água (utilizando um ergômetro de brações específico; estudo 1) e dentro d’água (utilizando o MAD System; estudo 3), combinados com medidas fisiológicas e biomecânicas, incluindo a eficiência da braçada. A velocidade máxima em 200 m teve como determinantes o equilíbrio entre variáveis biomecânicas (75% das variâncias pôde ser explicado pela potência mecânica externa e a eficiência da braçada; 98% das variâncias pôde ser explicado pela potência mecânica externa, eficiência propulsiva e o coeficiente de arrasto) e variáveis fisiológicas (98% das variâncias pôde ser explicado pela potência metabólica total e o custo energético). Ainda, a contribuição da pernada para a velocidade de nado aumentou com o aumento da frequência de braçadas (e da velocidade). Assim, ajustes individuais relativamente à contribuição da pernada devem ser considerados no cálculo da eficiência da braçada ao se nadar o nado crawl “completo” (usando braços e pernas). Por fim, os diferentes métodos fornecem valores de eficiência significativamente diferentes, embora haja concordância entre os mesmos. Portanto, valores de eficiência da braçada devem ser interpretados com cautela, considerando o método utilizado. / The main topic of this thesis was the arm stroke efficiency in front crawl swimming. Hence, it was developed in three original articles aiming to: (1) investigate the interplay between propelling efficiency and arm’s power output in determining the maximal speed in front crawl swimming, (2) estimate the effects of leg kick on the swimming speed and on arm stroke efficiency in front crawl, and (3) to compare different methods to assess the arm stroke efficiency and to identify the main biophysical predictors of maximal speed in 200 m swimming with the arms only. Different approaches were used to quantify the arm stroke efficiency. For instance, the paddle-wheel model (studies 1, 2, and 3), the ratio forward speed/hand speed (study 3), and the MAD System approach (study 3). The leg kick contribution was estimated individually, considering the differences in speed at paired stroke frequencies, in a range of speeds. Useful and non-useful components of the total mechanical power exerted by the arm stroke were obtained from dry land (using a customized arm-crank ergometer; study 1) and swimming protocols (using the MAD System; study 3), combined to the assessment of physiological and biomechanical parameters, including the arm stroke efficiency. The maximal speed in 200 m was determined by the balance between biomechanical (75% of the variances explained by the external mechanical power and the arm stroke efficiency; 98% of the variances explained by the external mechanical power, the arm stroke efficiency and the speed-specific drag) and physiological parameters (98% of the variances explained by the total metabolic power and the energy cost of swimming). Moreover, leg kick contribution to forward speed increased from low to maximal stroke frequencies (and speeds) and individual adjustments to the leg kick contribution should be considered when assessing the arm stroke efficiency in “full front crawl stroke” front crawl. Furthermore, the different methods provided significantly different values of arm stroke efficiency, although they agreed with each other. Therefore, arm stroke efficiency data should be interpreted carefully, considering the method used.
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Eficiência da braçada no nado crawl : atualização do estado da arte / The arm stroke efficiency in front crawl swimming : updating the state of the artSilveira, Ricardo Peterson January 2016 (has links)
O tópico principal desta tese de doutorado foi a efficiência da braçada no nado crawl. A tese foi composta e dividida em três artigos originais, com o objetivo de: (1) investigar as relações existentes entre a eficiência da braçada e a potência de membros superiores na determinação da velocidade máxima do nado crawl, (2) estimar os efeitos da pernada na velocidade de nado e no cálculo da eficiência da braçada no nado crawl, e (3) comparar os diferentes métodos utilizados para estimativa da eficiência da braçada e identificar os principais preditores biofísicos da velocidade máxima em 200 m crawl utilizando apenas os braços. Diferentes métodos foram utilizados para quantificar a eficiência da braçada, como o modelo da “roda de pás” (estudos 1, 2, e 3), a razão entre a velocidade de nado e a velocidade deslocamento da mão (estudo 3), e o método utilizando o MAD System (estudo 3). A contribuição da pernada foi estimada individualmente, considerando as diferenças de velocidade de nado para uma determinada frequência gestual, em diferentes intensidades. Os componentes úteis e não-úteis para a potência mecânica total exercida pela braçada foram obtidos por meio de protocolos fora d’água (utilizando um ergômetro de brações específico; estudo 1) e dentro d’água (utilizando o MAD System; estudo 3), combinados com medidas fisiológicas e biomecânicas, incluindo a eficiência da braçada. A velocidade máxima em 200 m teve como determinantes o equilíbrio entre variáveis biomecânicas (75% das variâncias pôde ser explicado pela potência mecânica externa e a eficiência da braçada; 98% das variâncias pôde ser explicado pela potência mecânica externa, eficiência propulsiva e o coeficiente de arrasto) e variáveis fisiológicas (98% das variâncias pôde ser explicado pela potência metabólica total e o custo energético). Ainda, a contribuição da pernada para a velocidade de nado aumentou com o aumento da frequência de braçadas (e da velocidade). Assim, ajustes individuais relativamente à contribuição da pernada devem ser considerados no cálculo da eficiência da braçada ao se nadar o nado crawl “completo” (usando braços e pernas). Por fim, os diferentes métodos fornecem valores de eficiência significativamente diferentes, embora haja concordância entre os mesmos. Portanto, valores de eficiência da braçada devem ser interpretados com cautela, considerando o método utilizado. / The main topic of this thesis was the arm stroke efficiency in front crawl swimming. Hence, it was developed in three original articles aiming to: (1) investigate the interplay between propelling efficiency and arm’s power output in determining the maximal speed in front crawl swimming, (2) estimate the effects of leg kick on the swimming speed and on arm stroke efficiency in front crawl, and (3) to compare different methods to assess the arm stroke efficiency and to identify the main biophysical predictors of maximal speed in 200 m swimming with the arms only. Different approaches were used to quantify the arm stroke efficiency. For instance, the paddle-wheel model (studies 1, 2, and 3), the ratio forward speed/hand speed (study 3), and the MAD System approach (study 3). The leg kick contribution was estimated individually, considering the differences in speed at paired stroke frequencies, in a range of speeds. Useful and non-useful components of the total mechanical power exerted by the arm stroke were obtained from dry land (using a customized arm-crank ergometer; study 1) and swimming protocols (using the MAD System; study 3), combined to the assessment of physiological and biomechanical parameters, including the arm stroke efficiency. The maximal speed in 200 m was determined by the balance between biomechanical (75% of the variances explained by the external mechanical power and the arm stroke efficiency; 98% of the variances explained by the external mechanical power, the arm stroke efficiency and the speed-specific drag) and physiological parameters (98% of the variances explained by the total metabolic power and the energy cost of swimming). Moreover, leg kick contribution to forward speed increased from low to maximal stroke frequencies (and speeds) and individual adjustments to the leg kick contribution should be considered when assessing the arm stroke efficiency in “full front crawl stroke” front crawl. Furthermore, the different methods provided significantly different values of arm stroke efficiency, although they agreed with each other. Therefore, arm stroke efficiency data should be interpreted carefully, considering the method used.
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Eficiência da braçada no nado crawl : atualização do estado da arte / The arm stroke efficiency in front crawl swimming : updating the state of the artSilveira, Ricardo Peterson January 2016 (has links)
O tópico principal desta tese de doutorado foi a efficiência da braçada no nado crawl. A tese foi composta e dividida em três artigos originais, com o objetivo de: (1) investigar as relações existentes entre a eficiência da braçada e a potência de membros superiores na determinação da velocidade máxima do nado crawl, (2) estimar os efeitos da pernada na velocidade de nado e no cálculo da eficiência da braçada no nado crawl, e (3) comparar os diferentes métodos utilizados para estimativa da eficiência da braçada e identificar os principais preditores biofísicos da velocidade máxima em 200 m crawl utilizando apenas os braços. Diferentes métodos foram utilizados para quantificar a eficiência da braçada, como o modelo da “roda de pás” (estudos 1, 2, e 3), a razão entre a velocidade de nado e a velocidade deslocamento da mão (estudo 3), e o método utilizando o MAD System (estudo 3). A contribuição da pernada foi estimada individualmente, considerando as diferenças de velocidade de nado para uma determinada frequência gestual, em diferentes intensidades. Os componentes úteis e não-úteis para a potência mecânica total exercida pela braçada foram obtidos por meio de protocolos fora d’água (utilizando um ergômetro de brações específico; estudo 1) e dentro d’água (utilizando o MAD System; estudo 3), combinados com medidas fisiológicas e biomecânicas, incluindo a eficiência da braçada. A velocidade máxima em 200 m teve como determinantes o equilíbrio entre variáveis biomecânicas (75% das variâncias pôde ser explicado pela potência mecânica externa e a eficiência da braçada; 98% das variâncias pôde ser explicado pela potência mecânica externa, eficiência propulsiva e o coeficiente de arrasto) e variáveis fisiológicas (98% das variâncias pôde ser explicado pela potência metabólica total e o custo energético). Ainda, a contribuição da pernada para a velocidade de nado aumentou com o aumento da frequência de braçadas (e da velocidade). Assim, ajustes individuais relativamente à contribuição da pernada devem ser considerados no cálculo da eficiência da braçada ao se nadar o nado crawl “completo” (usando braços e pernas). Por fim, os diferentes métodos fornecem valores de eficiência significativamente diferentes, embora haja concordância entre os mesmos. Portanto, valores de eficiência da braçada devem ser interpretados com cautela, considerando o método utilizado. / The main topic of this thesis was the arm stroke efficiency in front crawl swimming. Hence, it was developed in three original articles aiming to: (1) investigate the interplay between propelling efficiency and arm’s power output in determining the maximal speed in front crawl swimming, (2) estimate the effects of leg kick on the swimming speed and on arm stroke efficiency in front crawl, and (3) to compare different methods to assess the arm stroke efficiency and to identify the main biophysical predictors of maximal speed in 200 m swimming with the arms only. Different approaches were used to quantify the arm stroke efficiency. For instance, the paddle-wheel model (studies 1, 2, and 3), the ratio forward speed/hand speed (study 3), and the MAD System approach (study 3). The leg kick contribution was estimated individually, considering the differences in speed at paired stroke frequencies, in a range of speeds. Useful and non-useful components of the total mechanical power exerted by the arm stroke were obtained from dry land (using a customized arm-crank ergometer; study 1) and swimming protocols (using the MAD System; study 3), combined to the assessment of physiological and biomechanical parameters, including the arm stroke efficiency. The maximal speed in 200 m was determined by the balance between biomechanical (75% of the variances explained by the external mechanical power and the arm stroke efficiency; 98% of the variances explained by the external mechanical power, the arm stroke efficiency and the speed-specific drag) and physiological parameters (98% of the variances explained by the total metabolic power and the energy cost of swimming). Moreover, leg kick contribution to forward speed increased from low to maximal stroke frequencies (and speeds) and individual adjustments to the leg kick contribution should be considered when assessing the arm stroke efficiency in “full front crawl stroke” front crawl. Furthermore, the different methods provided significantly different values of arm stroke efficiency, although they agreed with each other. Therefore, arm stroke efficiency data should be interpreted carefully, considering the method used.
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Konceptkonstruktion av främre stabilisatorer -För en tunnelborrningsmaskin / Front Jack Design - of a tunnel boring machineGrelsson, Petter January 2016 (has links)
Denna rapport är resultatet av ett examensarbete på KTHs master-program för maskinkonstruktion i samarbete med Atlas Copco och Svea Teknik. Atlas Copco utvecklar en tunnelborrningsmaskin som trycker sig framåt och glider på skidor under borrning. Detta har visats sig ge stora friktionsförluster mellan det ojämna gruvgolvet och skidan vilket gör att de behöver en alternativ lösning på detta problem som klarar lasterna från borrning och maskinens egenvikt samt reducerar friktionen i maskinens längdriktning. Konceptutvecklingen var indelad i fyra stora delsteg: konceptgenerering, val av koncept, vidareutveckling och analys och utvärdering. Projektet avser endast konceptutveckling, ingen fullständig konstruktion. Några komponenter kunde bli omkonstruerade av Atlas Copco vid behov, de främre stingrarna som håller den stabil mot taket fick inte ändras, inga ritningar ritades, ingen detaljerad FEM-modellering och inte alla externa komponenter blev valda. Två koncept togs till vidareutveckling genom Pughs beslutsmatris: The Slide Guide och The Rocker Bogie. CAD modeller ritades och blev analyserade med avseende på strukturella laster och friktionskoefficienter jämfört med den befintliga lösningen. The Slide Guide klarar alla krav som kunde jämföras och The Rocker Bogie klarade inte utrymmeskraven och skulle kräva omfattande omkonstruktion av main body för att fungera. Koncepten blev utvärderade med hjälp av olika beräkningar och FEM analys / This report is the result of a master thesis at KTH Machine Design in cooperation with Atlas Copco and Svea Teknik. Atlas Copco is developing a Tunnel Boring Machine that pushes itself forward on steel skids using a torque tube when boring. This has proven to suffer from large frictional forces between the rough mine floor and the skid and they need an alternative solution to hold the loads of the machine while boring and reducing the friction when propelling itself forward. The concept development was divided into four main stages, concept generation, concept selection, further development, analysis and evaluation. The project includes only concept development, no complete designs. Some parts could be redesigned by Atlas Copco if needed, the front stingers supporting against the roof was not to be redesigned, no drawings was made, no detailed FEA modeling was done and not all external components was chosen. Two concepts where chosen for further development using the PUGH’s decision matrix, The Slide Guide and The Rocker Bogie. CAD models was developed and analyzed regarding loads and friction compared to the existing solution. The Slide Guide clears all requirements that could be measured and the Rocker Bogie does not fit within the geometrical limits available without extensive redesign of the Main Body. This was verified using calculations and structural FEA.
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A tramming concept for a mechanical rock excavation machine / Ett trammningskoncept för en mekanisk bergavverkningsmaskinBlomqvist, Sara January 2015 (has links)
This report is the result of a thesis project at KTH in cooperation with Svea Teknik AB and Atlas Copco Mining and Rock Excavation. Atlas Copco is currently developing a family of machines for mechanical rock excavation. All machines in the family have two propulsion methods. The goal of this project has been to reduce the number of propulsion methods down to one, in one of these machines, the Mobile miner. The project has been divided into three main phases; background studies, concept development and documentation. The concept development phase has in turn been divided into four parts: generation, evaluation, development and validation. During the project no physical prototypes, drawings, component selections, software programming, calculations of friction losses or detailed FEM analysis were made. Nine concepts were developed. These were assessed with respect to a product specification using a weighted PUGH-matrix. The concept that received the highest ranking in the PUGH-matrix was six arms that are used to pull the machine forward. The concept was developed with respect to applicability, durability and fatigue. This resulted in a concept with four arms similar to scissor lift tables placed horizontally. The function has been verified using CAD-models, calculation of safety factors against fatigue and FEM-models. The only specification that was not achieved was the speed. / Denna rapport är resultatet av ett examensarbete på KTH i samarbete med Svea Teknik AB och Atlas Copco Mining and Rock Excavation. Atlas Copco utvecklar för närvarande en familj av maskiner för mekanisk bergsbrytning. Samtliga maskiner i familjen har två framdrivningsmetoder. Målet med detta projekt har varit att reducera antalet framdrivningsmetoder till en i en av dessa maskiner, Mobile minern. Projektet har varit uppdelat i tre huvudfaser: bakgrundsstudier, konceptutveckling och dokumentation. Konceptutvecklingen har i sin tur varit uppdelad i fyra delar: generering, bedömning, utveckling och validering. I projektet har inga fysiska prototyper, ritningar, komponentval, mjukvaruprogrammering, beräkningar av friktionsförluster eller detaljerade FEM-analyser gjorts. Nio koncept togs fram. Dessa bedömdes med avseende på en produktspecifikation med hjälp aven viktad PUGH-matris. Det koncept som fick högst rankning i PUGH-matrisen var sex armar som används för att dra maskinen framåt. Konceptet utvecklades med avseende på applicerbarhet, hållbarhet och utmattning och slutade som ett koncept med fyra armar liknande saxlyftbord som lagts horisontellt. Funktionen har verifierats genom CAD-modeller, beräkning av säkerhetsfaktorer mot utmattning och FEM-modeller. Den enda produktspecifikationen som inte uppnåddes var farten.
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Modelové řešení energetického zásobení místní dopravy a přepravy alternativními zdroji / Model Solutions to Energy Supply Local Transportation and Alternative Sources of TransportationKrtička, Miroslav January 2011 (has links)
The Thesis are focused on the area of strategic management using the strategies selection and decision making processes, based on the Game Theory apparatus. The analyses of local energy sources potential and possible use in local transportation are the basis of the Thesis. The problems of energy maintenance and efficient utilisation have not decreasing its importance even in the situation of technology & technical improvements; there are no universally-suitable processes found in this area. One of the approaches should be in the philosophy of maximising the utilisation of local resources to minimise the expenses of the transportation of the energies itself. The Thesis are focused on the increased efficiency of local energy-resources utilisation combined with continuously increasing energy demands in the area of transportation area. The Target is to construct model, having proportionally characterised the suitable strategies to the decision -- making in the areas of local energies production and/or their utilisation in the area of the local transportation demand saturation. The Game Theory approaches creating the basis for the different interested groups; it allows to compare the advantages of different options / strategies of the progress, having respected counter-strategies of the other parties of the conflict situation. The recommendation of the most advantageous strategies for the individual interested groups of the conflict (transport companies, potential producers of energies from local resources, society) is the result of the process. The construction of the model, having the ability to compare the merits of different options -- related to the energies-utilisation (strategies) is the contribution of the thesis. There is specific approach given to allow finding the results suitable for both interested parties of the conflict situation (producers of the organic matter for the energy production, potential energy producers, local transporting companies). All the results are based mainly on the verified statistic data sources. Resulting model allow good and transparent comparison of different strategies of the different interested groups related to the energy resources. The results could work not only in the area of theoretical calculations, but also companies and interested parties strategies recommendations to their own decision-making processes.
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MASCOT Follow-on Mission Concept Study with Enhanced GNC and Propulsion Capability of the Nano-lander for Small Solar System Bodies (SSSB) MissionsChand, Suditi January 2020 (has links)
This thesis describes the design, implementation and analysis for a preliminary study for DLR's MASCOT lander's next mission to Small Solar System Bodies (SSSB). MASCOT (Mobile Asteroid Surface Scout) is a nano-lander that flew aboard Hayabusa2 (JAXA) to an asteroid, Ryugu. It is a passive nano-spacecraft that can only be deployed ballistically from a hovering spacecraft. Current research focusses on optimizing similar close-approach missions for deploying landers or small cubesats into periodic orbits but does not provide solutions with semi-autonomous small landers deployed from farther distances. This study aims to overcome this short-coming by proposing novel yet simple Guidance, Navigation and Control (GNC) and Propulsion systems for MASCOT. Due to its independent functioning and customisable anatomy, MASCOT can be adapted for several mission scenarios. In this thesis, a particular case-study is modelled for the HERA (ESA) mission. The first phase of the study involves the design of a landing trajectory to the moon of the Didymos binary asteroid system. For a preliminary analysis, the system - Didymain (primary body), Didymoon (secondary body) and MASCOT (third body) - are modelled as a Planar Circular Restricted Three Body Problem (PCR3BP). The numerical integration methodology used for the trajectory is the variable-step Dormand–Prince (Runge Kutta) ODE-4,5 (Ordinary Differential Equation) solver. The model is built in MATLAB-Simulink (2019a) and refined iteratively by conducting a Monte Carlo analysis using the Sensitivity Analysis Tool. Two models - a thruster-controlled system and an alternative hybrid propulsion system of solar sails and thrusters - are simulated and proven to be feasible. The results show that the stable manifold near Lagrange 2 points proposed by Tardivel et. al. for ballistic landings can still be exploited for distant deployments if a single impulse retro-burn is done at an altitude of 65 m to 210 m above ground with error margins of 50 m in position, 5 cm/s in velocity and 0.1 rad in attitude. The next phase is the conceptual design of a MASCOT-variant with GNC abilities. Based on the constraints and requirements of the flown spacecraft, novel GNC and Propulsion systems are chosen. To identify the overriding factors in using commercial-off-the-shelf (COTS) for MASCOT, a market survey is conducted and the manufacturers of short-listed products are consulted. The final phase of the study is to analyse the proposed equipment in terms of parameter scope and capability-oriented trade-offs. Two traceability matrices, one for devised solutions and system and another for solutions versus capabilities, are constructed. The final proposed system is coherent with the given mass, volume and power constraints. A distant deployment of MASCOT-like landers for in-situ observation is suggested as an advantageous and risk-reducing addition to large spacecraft missions to unknown micro-gravity target bodies. Lastly, the implications of this study and the unique advantages of an enhanced MASCOT lander are explored for currently planned SSSB missions ranging from multiple rendezvous, fly-by or sample-return missions. Concluding, this study lays the foundation for future work on advanced GNC concepts for unconventional spacecraft topology for the highly integrated small landers. / <p>This thesis is submitted as per the requirements for the Spacemaster (Round 13) dual master's degree under the Erasmus Mundus Joint Master's Degree Programme. </p> / MASCOT team, DLR
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