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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

Ergonomisk och användarvänlig släplift anpassad för skidanläggningarnas och fjällturismens utveckling. : Rapport, examensarbete 2012

Olausson, Hanna January 2012 (has links)
Surface lift adapted for today’s user  Today’s T-bar lift looks almost the same as when it was launched in 1938, even though a lot has happened in the ski and mountain industries. New equipment has developed without any major adjustment to the lift. Snowboard, sit ski and downhill biking are just some examples of the evolution that demands new seating positions. It’s also very common for families to spend their holidays in the mountains nowadays. These are users whit a lot of different needs, for example how to ride with different heights, different gears and different skill level. My degree work has focused on developing a new surface lift that is adapted to the different needs of today’s users. A surface lift that makes the ride a nice experience that ends with a big smile and a lot of energy to spend on the way down. This report describes in detail how I through the design process and in close contact with users and experts came up with a realistic concept that will satisfy both the manufacturers, producers and the users. / Uphill
2

HUMAN BLOOD LACTATE AND AMMONIA LEVELS AFTER SUPRAMAXIMAL UPHILL AND DOWNHILL RUNNING

MIYAMURA, MIHARU, YAMAZAKI, YOSHIHIKO, OHKUWA, TETSUO, ITOH, HIROSHI 27 December 1996 (has links)
No description available.
3

A Polynomial Time Algorithm for Downhill and Uphill Domination

Deering, Jessie, Haynes, Teresa W., Hedetniemi, Stephen T., Jamieson, William 01 September 2017 (has links)
Degree constraints on the vertices of a path allow for the definitions of uphill and downhill paths. Specifically, we say that a path P = vi, v2,⋯ vk+1 is a downhill path if for every i, 1 ≤ i ≤ k, deg(vi) ≥ deg(v1+1). Conversely, a path π = u1, u2,⋯ uk+1 is an uphill path if for every i, 1 ≤ i ≤ k, deg(ui) ≤ deg(ui+1). The downhill domination number of a graph G is the minimum cardinality of a set S of vertices such that every vertex in V lies on a downhill path from some vertex in S. The uphill domination number is defined as expected. We give a polynomial time algorithm to find a minimum downhill dominating set and a minimum uphill dominating set for any graph.
4

Downhill and Uphill Domination in Graphs

Deering, Jessie, Haynes, Teresa W., Hedetniemi, Stephen T., Jamieson, William 01 February 2017 (has links)
Placing degree constraints on the vertices of a path yields the definitions of uphill and downhill paths. Specifically, we say that a path π = v1, v2, ⋯ vk+1 is a downhill path if for every i, 1 ≤ i ≤ k, deg(v1) ≥ deg(vi+1). Conversely, a path π = u1, u2, ⋯ uk+1 is an uphill path if for every i, 1 ≤ i ≤ k, deg(u1) ≤ deg(ui+1). The downhill domination number of a graph G is defined to be the minimum cardinality of a set S of vertices such that every vertex in V lies on a downhill path from some vertex in S. The uphill domination number is defined as expected. We explore the properties of these invariants and their relationships with other invariants. We also determine a Vizing-like result for the downhill (respectively, uphill) domination numbers of Cartesian products.
5

Análise de corrosão e comportamento mecânico de ligas de alumínio aeronáutico 7075-T6 após tratamento térmico usando a técnica uphill / Corrosion and mechanical behavior analysis of 7075-T6 aeronautical aluminum alloys after heat treatment using uphill technique

Mattos, Wellington da Silva 16 July 2018 (has links)
Este trabalho descreve o conceito do processo uphill aplicado no tratamento térmico de ligas de alumínio. Uma técnica pouco difundida na literatura e com aplicações limitadas na indústria aeroespacial. É um processo também conhecido em inglês por deep freezing ou tri-cycle stress relieving. A técnica uphill é interessante do ponto de vista de redução de tensão residual, podendo atingir reduções maiores do que 80% como tem sido reportado na literatura. Este processo basicamente consiste em imergir a peça, depois da têmpera, em um ambiente criogênico, com o objetivo de obtenção de uma homogeneização da temperatura, seguido da transferência para uma câmara de vapor quente para obter um gradiente de temperatura, mantendo-se ainda as propriedades mecânicas obtidas com o tratamento térmico. Este trabalho mostra o desenvolvimento de um sistema uphill e a avaliação de propriedades mecânicas (tração, dureza e fadiga) e de corrosão. Os resultados mostraram que o sistema desenvolvido produziu gradientes térmicos elevados, responsável pelas reduções, de tensão e distorções. Com relação às propriedades mecânicas e resultados de corrosão, verificou-se que a técnica uphill traz benefícios quando comparada aos métodos tradicionais de têmpera e envelhecimento, com destaque o aumento de tenacidade à fratura e vida em fadiga sem perda significativa de resistência à corrosão, mantendo a linha de desempenho das têmperas com alta taxa de resfriamento. Embora com efeitos mais significativos para maiores espessuras, a técnica foi empregada com sucesso para peças de até ¼ pol. [6,35 mm]. / This work describes the concept of uphill process applied to heat treatment of aluminum alloys. Uphill applied in aluminum aerospace industry, but it is not very widespread in the techno-scientific literature. It is also a process known as \"deep freezing\" or \"tri-cycle stress relieving\". Uphill technique is much interesting from the point of view of residual stress reduction that can be higher than 80% as has been reported. This process basically consists of immersing the part in cryogenic bath, after quenching, getting homogenization and stabilization temperature of the part, followed by transferring for a hot steam chamber to obtain a temperature gradient. Stress reduction is obtained without deleterious effect in mechanical properties gained with the heat treatment. This work shows the development from a uphill system and the mechanical properties evaluation (tensile, hardness and fatigue) and corrosion. Results shown that the developed system can produce high thermal gradients generating stresses and distortion reduction. Related to mechanical properties and corrosion results, it was verified that the uphill technique brings benefits when compared to the traditional quenching and aging methods, highlighting the increase in toughness and fatigue life without meaningful loss of corrosion resistance and maintaining the performance when highest cooling rate is used. Although with more significant effect for thicker parts, this process was successfully applied for components up to ¼ pol.
6

Some Aspects of Improving Initial Filling Conditions and Steel Cleanliness by Flow Pattern Control Using a Swirling Flow in the Uphill Teeming Process

Tan, Zhe January 2013 (has links)
The flow pattern has widely been recognized to have an impact on the exogenous non-metallic inclusion generation in the gating system and mold flux entrapment in the uphill teeming process. Thus, a well-controlled flow pattern during the teeming process can improve the quality of ingots and further increase the yield during steel production. The current study focused on investigating and optimizing the flow pattern of steel in the gating system and molds to improve steel cleanliness during the initial filling moment. A mathematical model considering a trumpet was initially compared to a reduced model only considering part of the runner channel. Thereafter, the influence of swirl blades implemented at the bottom of the vertical runner on the improvement of initial filling conditions in the molds was investigated in a model considering the entire mold system including a trumpet. The effects of a swirl blade orientation on a swirling flow were further discussed. The simulation results, when utilizing swirl blades, were also verified by plant trials performed at Scana Steel. In addition, a new novel swirling flow generation component, TurboSwirl, was studied in a model considering the entire mold system including a trumpet. The model was based on modifications of the refractory geometry at the elbow of the runners near the mold without the usage of an inserted flow control device in the gating system. Owing to its great potential for improving the flow pattern of steel during the initial filling moment, the effect of TurboSwirl on steel cleanliness was also studied. The results showed that the initial filling conditions during the uphill teeming process can be improved by using a swirl blade or a TurboSwirl in the gating system. This makes it possible to further decrease the initial position of mold powder bags. In addition, it reduces the possibilities of exogenous non-metallic inclusion generation in the gating system as well as mold flux entrapment in the mold during the uphill teeming process. However, the utilization of swirl blades created a considerable amount of droplets when steel entered the molds during the first couple of seconds, which also was verified by the plant trials. The introduction of TurboSwirl showed a greater potential than a swirl blade due to a more evenly distributed swirling flow. The DPM model adopted in the simulations revealed that the TurboSwirl can improve steel cleanliness by increasing the non-metallic inclusion collision rate both with respect to Stokes and turbulent collisions. / <p>QC 20130204</p>
7

Plant Experiment Using a Swirl Blade in the Uphill Teeming Process

Svensson, Jennie January 2011 (has links)
The purpose of this thesis has been to evaluate the use of a swirl blade in the uphill teeming process through plant trials. Two series of trials were carried out at Scana Steel Stavanger AS. In the trials a divergent entrance nozzle with a 62° outlet angle were used when casting duplex stainless steel on a base plate with two 6.2 tons ingots. All molds were burned onto the ingots; leading to problems with emptying the ingots from the molds and severe damages on the molds. To get a better insight during the casting and understand why the molds were burned onto the ingots; during the second series of trials one mold on each base plate were filmed in the beginning of the casting process. Evaluation of the castings indicated that splashing on the mold wall at an initial stage was one reason for the mold burned onto the ingot. Further, material samples were collected to evaluate the non-metallic inclusion composition and distribution with SEM when casting with a swirl blade compared to when casting without. The area percentage of the inclusions in the samples was 1% and 2% for samples casted with and without swirl blade respectively with d=2.8 mm. The inclusion size also varied for samples casted with and without swirl blade; 98% of the inclusions were in the size range of 0-10 μm when casted with and in the size range 0-20 μm when casted without swirl blade. / Syftet med denna uppsats har varit att utvärdera användningen av swirlblad i götgjutningsprocessen. Två serier med försök har utförts på Scana Steel Stavanger AS. I försöken användes en inloppssten med 62°-vinklat utlopp, där duplexa rostfria stål göts på stigplan med två 6,2 tons kokiller. Alla kokiller brände fast på göten, vilket ledde till svårigheter vid urtag av göten samt skador på kokillerna. För att få en bättre förståelse av varför kokillerna brände fast, filmades ett göt på vardera stigplan under den andra försöksserien. Utvärdering av försöken indikerar att en anledning till att kokillerna brände fast på göten var att det stänkte upp stål på kokillväggen i ett tidigt stadium. Vidare har materialprover samlats in för att utvärdera sammansättningen samt utspridningen av icke-metalliska inneslutningar i SEM då göt gjutits med swirlblad jämfört med utan. Area procenten i proverna var 1% och 2% då proverna gjutits med respektive utan swirlblad, med d=2.8 mm. Även storleken på inneslutningarna i prover som gjutits med och utan swirlblad skiljde sig åt, 98% av inneslutningarna var i storleksintervallet 0-10 μm för prover gjutna med swirlblad medan de som gjutits utan var i storleksintervallet 0-20 μm. / JK24053
8

Anatomical and Biomechanical Factors Related to Running Economy in Uphill and Downhill Running

Taylor, McKenna 03 August 2022 (has links)
Much is known about running economy while running on level ground surfaces. However, with the dynamic of elevation changes during running, more research is needed to understand how various grades that will favor respective mechanics. PURPOSE: In this study, we focused on determining whether certain running mechanics and anatomy would predict a runner's oxygen uptake between downhill versus uphill running. METHODS: Twenty-one experienced runners completed six 5-min running trials (1 shoe x 3 grades x 2 visits) in a Saucony marathon racing shoe model (Type A) on level (3.83 m/s), uphill (+4% grade at 3.35 m/s), and downhill ( ˆ’4% grade at 4.46 m/s) conditions. These treadmill speeds at each grade were predicted as metabolic equivalents through all grades. We measured submaximal oxygen uptake and carbon dioxide production during the entire trial duration with the last 3 min of each trial being averaged. A best-fitting line was generated through oxygen uptake versus grade to classify whether runners were more economical in uphill or downhill conditions relative to other subjects. The slope of this line indicated whether runners were more economical at uphill or downhill running, where a positive slope represented a more economical uphill versus downhill runner. Various running mechanics were measured using Vicon Nexus and a Bertec treadmill. A linear regression determined any correlations between peak vertical force, stride rate, plantar velocity, and ground time against uphill/downhill running ability. RESULTS: Peak vertical force was the only factor associated with the slope of oxygen uptake versus grade (running grade ability; p < 0.01). The slope of oxygen uptake versus grade averaged 0.076 ± 0.278 ((ml/kg/min) / % grade). CONCLUSION: Runners that naturally prefer a higher peak vertical force when running on level ground led to a lower running grade ability (lower oxygen uptake during downhill versus uphill running).
9

The Effects of Footwear Longitudinal Bending Stiffness on the Energetics and Biomechanics of Uphill Running

Ortega, Justin Angelo 28 October 2022 (has links)
There has been a prevalence of long-distance running footwear incorporating carbon-fiber plates within their midsoles, effectively increasing their longitudinal bending stiffness (LBS). This modification of modern racing footwear has occurred concurrently with large improvements in running times (Bermon et al., 2021), putting into question how these footwear components affect performance (Muniz-Pardos et al., 2021). The current literature has investigated this at level running, but with the increasing popularity of trail running, it is of interest to investigate whether the benefits found during level running translate to graded running. Therefore, the overall aim of this study was to investigate the effects of increased footwear midsole longitudinal bending stiffness (i.e. carbon-fiber plates) on running energetics and biomechanics at various inclines. The effects of high LBS (Nike Vaporfly 4% with midsole intact) and low LBS (Nike Vaporfly 4% with mediolateral cuts made at the forefoot of the midsole through the carbon-fiber plate) footwear conditions were compared for running at 0°, 6°, and 12° inclines. Running energetics and biomechanics data were quantified by measuring metabolic rate and lower leg joint mechanics (from motion capture and ground reaction force measurements). Results from this study suggest that increasing longitudinal bending stiffness within the footwear midsoles has limited influence on running energetics (small non-significant improvements of metabolic power at all inclines), but has considerable effects on the biomechanics of the ankle and MTP joints. However, the most important between shoe differences were independent of grade, suggesting that the benefits of modern racing shoe observed for level running can be expected to translate to steep uphill running. Nevertheless, it should be noted that this study was only able to collect and use data for analysis from a limited number of participants (n=7), and therefore is underpowered, so there may be significant differences that go undetected
10

Estudo do comportamento veicular em manobras de saídas de aclives através de um programa computacional em Matlab-Simulink / Behavior study of vehicle startability on grade maneuver through a computer program in Matlab-Simulink

Ferezini Junior, Jacob 17 December 2010 (has links)
O desempenho de um veículo de passeio em manobras de arrancada em aclives elevados é um fator muito importante a ser considerado no desenvolvimento de um novo projeto ou modificação de um projeto já existente. Este desempenho é influenciado por várias características do veículo, tais como: perfil e forma da curva de torque do motor, massa do veículo, relações de transmissão, tamanho do pneu entre outros. Este trabalho propõe uma metodologia de simulação para prever o desempenho de um veículo com tração dianteira em aclives elevados, através da utilização de um modelo de simulação desenvolvido na plataforma Matlab Simulink. Essa metodologia consiste na validação de um modelo de simulação capaz de representar todo o procedimento que envolve a saída de um veículo em um aclive elevado, levando em consideração a variação da rotação do motor, do pedal do acelerador, acoplamento da embreagem e o acionamento do freio de estacionamento. Uma medição real em veículo foi feita onde se registrou este comportamento e estes dados foram utilizados como valores de entrada no modelo de simulação. Para a correlação do modelo de simulação, foram utilizados os gráficos que representam a variação do espaço percorrido, velocidade e aceleração longitudinal, onde os resultados práticos e teóricos mostraram-se próximos mostrando que o modelo de simulação desenvolvido em MatLab/Simulink é uma opção a ser utilizada, principalmente nas fases inicias de projeto e para otimização de projetos já existentes. / The performance of a passenger vehicle maneuvering uphill sprint high is a very important factor to be considered in developing a new project or modifying an existing project. This performance is influenced by various characteristics of the vehicle, such as profile and shape of engine torque curve, vehicle weight, gear ratios, tire size and others. This paper proposes an analysis methodology to simulate the performance of a vehicle with front wheel drive in high slopes, through the use of a simulation model developed on the Matlab Simulink. This methodology consists in validating a simulation model capable of representing the entire procedure involving the removal of a vehicle in a high slope, taking into account the variation of engine speed, accelerator pedal, the clutch engaging and brake actuation parking. An actual measurement of vehicle was registered where this behavior and these data were used as input values in the simulation model. For the simulation model correlation, It was used the graphs represent the change in the space covered, vehicle speed and vehicle longitudinal acceleration, where the practical and theoretical results proved to be the next showing that the simulation model developed in Matlab/Simulink is an option be used, especially in the early stages of design and optimization of existing designs.

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