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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.
241

Factors related to cycling performance

Naukkarinen, Vesa 05 1900 (has links)
There were two primary goals in this investigation. The first goal was to determine if results from field tests (time-trials and a Conconi incremental test) are related to performance in mass-start long-distance bicycle races. The second goal was to investigate inter-relationships among field test variables. The testing variables measured were critical velocity (CV), Conconi anaerobic threshold (AT) velocity, 4mM AT velocity, fatigue index, peak blood lactate, and anaerobic work capacity. Participants were USCF 30 category 1 through 5 cyclists. Participants performed one 20.75 km and two 10.37 km all-out tests in the field. They also performed an incremental test. The tests were performed at one-week intervals. Results from the field tests were compared to recent mass-start racing performance. Results indicated that Conconi AT velocity was related to performance in a 161-km race. There was also a relationship between 4mM AT velocity and CV and between Conconi AT velocity and 4mM AT velocity. It was concluded that field tests might provide information about performance ability in mass-start long-distance bicycle races.
242

Solving the ‘first mile problem’: opportunities for bike-transit integration in Edmonton, Alberta

Yau, Derek 14 September 2016 (has links)
In an effort to shift reliance away from single-occupancy vehicles, many cities have been investing in active and public transportation, and promoting multi-modal travel. It has been recognized both academically and professionally that there is a need to address issues regarding access to transit stations and nodes – the ‘first mile problem.’ Many see bicycles as the answer to the first mile problem; however, scholarly literature has generally neglected exploring how to accommodate bicycles at different stations. This practicum investigates the first mile problem in Edmonton, Alberta, and identifies existing challenges with bicycle access to Edmonton’s Light Rail Transit (LRT) system. The findings suggest three distinct LRT ‘station types’, each requiring a nuanced suite of infrastructure improvements in order to encourage more bicycle access. Further, these improvements can only be realized through the development and execution of comprehensive policies and regulations that support cycling and bike-transit integration. / October 2016
243

Effects of Vegetation Structure and Canopy Exposure on Small-scale Variation in Atmospheric Deposition Inputs to a Mixed Conifer Forest in California

Griffith, Kereen 05 1900 (has links)
Data on rates of atmospheric deposition is limited in many montane ecosystems, where high spatial variability in meteorological, topographic, and vegetation factors contributes to elevated atmospheric inputs and to the creation of deposition hotspots. Addressing the ecological consequences of increasing deposition in these areas will require a better understanding of surface controls influencing atmospheric deposition rates at both large and small-scales. The overarching objective of this thesis research was to understand the influence of vegetation structure and canopy exposure on small-scale patterns of atmospheric sulfate, nitrate, and chloride deposition inputs to a conifer forest in the Santa Cruz Mountains, California. Throughfall ion fluxes (i.e., ions delivered in water that pass from the forest canopy to the forest floor), bulk deposition (i.e., primarily wet deposition), and rainfall data were collected during the rainy period from October 2012 to May 2013. Throughfall SO42-, Cl-, and NO3- fluxes were measured beneath eight clusters of Douglas fir (Pseudotsuga menziesii) trees (three trees per cluster) differing in tree size (i.e., diameter at breast height; DBH) and canopy exposure. In each cluster, a throughfall collector was placed 1-meter from the bole of an individual tree, for a total of 24 individual collectors. The position of each throughfall collector was recorded with a Trimble® GPS. In addition, tree height, tree diameter, and leaf area index, were measured for all trees. LiDAR data were obtained from GeoEarthScope’s Northern California Airborne LiDAR project and used to model the elevation (DEM), canopy surface height (DSM), tree height (CHM), slope, and curvature of the canopy surface across the entire study area. Over the rainy season, total throughfall flux of SO42--S, a conservative tracer of total deposition (wet + dry + fog), to Douglas fir clusters ranged from 1.44 - 3.84 kg S ha-1 wet season-1, while dry and fog deposition ranged from 0.13 -2.37 kg S ha-1 wet season-1. Total deposition to exposed mature tree clusters was 1.7-2.7 times higher than other clusters. Patterns of total Cl- fluxes (17.10 – 54.14 kg Cl- ha-1 wet season-1) resembled patterns of total SO42--S inputs. Overall, net throughfall fluxes (throughfall – bulk deposition) to Douglas fir trees clusters were more variable than total throughfall fluxes. Net SO42--S and Cl- fluxes to individual collectors increased with tree DBH and the convexity of the canopy surface. Compared to SO42--S and Cl- in throughfall, total NO3--N fluxes (0.17 - 4.03 kg N ha-1 wet season-1) were low and appeared to vary with small-scale changes in elevation. Geospatial technologies and remote sensing tools, such as LiDAR, are promising in the study of relationships between atmospheric deposition and topography (including vegetation), and in scaling-up estimates of atmospheric deposition to larger spatial scales. Understanding small-scale surface controls on atmospheric deposition has implications for different areas of research within geography, including modeling the spread of emerging infectious disease and assessing the effects of nitrogen cycling on native and invasive plant species composition.
244

Kineziologická analýza horizontálního přeskoku v cyklotrialu / Kinesiology analysis of the horizontal jump in bike trial

Eibl, Tomáš January 2016 (has links)
Title: Kinesiology analysis of the horizontal jump in bike trial Cíle práce: The aim of this thesis is to verify the use of non-specific strength-training funds for the development of horizontal jump in bike trial. Methods: Content analysis of documents Method interview with assistant work Mgr. Marek Jelinek Ph.D. Method interview with the technician when recording data Case Study riders The method of data collection using surface electromyography Data Analysis Data processing software MS Excel - evaluation of differences of values sized muscle action potential in the different types of exercise Synthesis - making inferences and discussions Results: The list of exercises for developing strength abilities of the lower limbs, which are part of non-specific resources and influence the development of the horizontal jump in cyklotrial. Ranking exercises, which are in accordance with the measured values for effective development of horizontal jump in bike trial. The exercises are sorted from highest values aktivity of all muscles: 1st Squat with free weights 2nd Jump from second place 3rd Deadlift 4th Plyometrie 5th High Jump 6th Legpress Key words: Cycling trails, biking, surface electromyography.
245

Effects of Neuromuscular Fatigue Resulting from Repeat Sprint Exercise Among Trained Cyclists on Measures of Strength and Power Performance

Blaisdell, Robert B. 01 August 2019 (has links)
The purpose of this dissertation is to better understand the role of repeated-sprint ability (RSA) and resulting fatigue in cyclists; how it relates to measures of aerobic power and strength and power performance indices- due to the nature of cycling competitions and the necessity of RSA for success. The first part of this dissertation attempted to elucidate the relationship between RSA and aerobic power and strength/ power measures in competitive cyclists. The purpose was to potentially illustrate the importance of the inclusion of strength and power training in the training regimen of cyclists. The findings showed several statistically significant relationships between variables of RSA and aerobic power or the isometric squat test. The second part of the dissertation examined the effects of fatigue induced from the acute bout of repeat sprint exercise on strength and power measures in three different recovery periods. It is commonplace for cyclists to have several heats in one day of racing. Examining the effects of fatigue on strength measures such as peak force and rate of force development could begin to delineate how an individual experiences fatigue based on their own characteristics, enabling them to design a training program to address these strengths/ weaknesses to optimize performance and decrease fatigue. The results from a repeated measures analysis of variance found no statistically significant effect on PF or RFD. Additional comparisons showed moderate effects of fatigue on RFD throughout the three post-RSE trials. There was also a moderate correlation between the RSE fatigue % decrement score and the isometric RFD fatigue % decrement score. What we may conclude from this dissertation is that fatigue has various causes and can vary with an individuals’ unique physiology and how they respond to performance variables on any specific day can vary. Development of increased strength and subsequent power, or “explosive strength”, may have advantages in competitive cycling. Coupling proper strength and power training with an aerobic training regimen, may greatly benefit the athlete by increasing their peak power output, economy of movement, delaying fatigue, improving anaerobic capacity, and overall enhancing their maximal speed.
246

Investigations of pond metabolism in temperate salt marshes of Massachusetts

Yoo, Gyujong January 2018 (has links)
Thesis advisor: Tara Pisani Gareau / Salt marshes provide important ecosystem services, including carbon sequestration. Permanently inundated ponds are prominent features in the marsh landscape, encompassing up to 60% of the total marsh area, but they are rarely considered in biogeochemical assessments. I investigated two ponds in Plum Island Estuary, MA to measure and analyze their metabolism. The ponds varied in size and vegetation cover. Oxygen concentrations and pH values were recorded in 15-minute intervals during the entire study period. The ponds regularly become hypoxic or anoxic during night. This is a problem for the estimation of respiration rates which are based on nighttime measurements. To investigate this potential underestimation, several approaches to estimate respiration were used. First, additional measurements of surface water concentrations of dissolved inorganic carbon were made. A comparison of respiration estimates based on oxygen and DIC changes during tidal isolation revealed a reasonable agreement for the most time but not during periods of high productivity during the day or late at night. At this point, oxygen concentrations are so depleted that a change in concentration – the indicator of respiration – is barely detectable. However, DIC based respiration rates indicate that respiration is occurring under these hypoxic/anoxic conditions. This saturation changes during periods of tidal inundation, when a nighttime peak in oxygen concentrations indicates that the flood water is relatively enriched in oxygen compared to the pond water. On three days, it was tested whether under these conditions the oxygen-based respiration rate was higher than under hypoxic conditions (i.e., during tidal isolation). The rates were indeed higher than those under tidal isolation but still not in the range of DIC-based rates. Overall, metabolic rates differed between the two ponds in magnitude, which is likely caused by different vegetation cover, but may be influenced by size, sampling period, and duration as well. / Thesis (BS) — Boston College, 2018. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Departmental Honors. / Discipline: Earth and Environmental Sciences.
247

An ethnography of global connections : the case of Critical Mass

Lopes, Katia Batista January 2016 (has links)
Submitted to the Department of Anthropology in partial fulfilment of the requirements for the degree Master of Arts (Anthropology) School of Social Science Faculty of Humanities, University of the Witwatersrand, 2016 / The primary purpose of this study is to identify the social characteristics of the Critical Mass event in Johannesburg, an event that forms part of an international movement. The international Critical Mass movement is made up of 350 participating cities around the world where cyclists ride as unregulated groups, on the last Friday of every month, to take back the streets from cars. My study investigates who rides in the Critical Mass event in Johannesburg, how they move through the inner city streets as a group and reasons given by the organisers and the participants for why the ride occurs. This study was conducted as a patchwork ethnography, where I participated in and observed the ride, but also collected secondary data (archives, maps, media sources, public reports and conferences/meetings) implicated at the ride. Using Anna Tsing’s (2005) conceptual frameworks ‘friction’ and ‘global connection’ I suggest that my findings point to the particularities, a number of contextual factors that reach beyond the ride itself, but are always already contingent on moments of friction during the ride. I explain that the moments of frictions make clear the multiple chains implicated during the ride, that is the everyday. I argue that these chains are dynamic connections to identity, spatial and discursive privilege during the ride. This account of the particularities of the Johannesburg event, as cycling in Africa, the global South, fill the gap in the research on Critical Mass that is focused on Western accounts of the ride. Furthermore, as an experimental approach in anthropology my use of the patchwork method and connections contribute to new and political ways of thinking about the global South. Lastly, my study provides a lens to look at cycling advocacy. / GR2017
248

Avaliação da interação solo-reforço por meio de ensaios de cisalhamento cíclico de interface / Evaluation of soil-reinforcement interaction by cyclic snear interface tests

Campos, Marcus Vinicius Weber de 04 October 2013 (has links)
O comportamento de solos reforçados depende amplamente da interação entre o solo e o reforço, baseado nas solicitações que o conjunto experimentará ao longo da sua vida útil. Tal interação é comumente caracterizada através de ensaios normatizados como o de arrancamento, que buscam simular as solicitações a que o conjunto estará sujeito. Porém, algumas estruturas reforçadas experimentam ações cíclicas de cargas móveis consideráveis, que dificilmente tem seu comportamento representado nestes ensaios comuns. Diante disso, esta pesquisa buscou aperfeiçoar o equipamento de ensaios cíclicos da Escola de Engenharia de São Carlos EESC-USP, a fim de realizar ensaios cíclicos em diferentes tipos de solos (uma areia, um silte argiloso e uma brita graduada simples), reforçados com uma geogrelha de poliéster comumente utilizada para reforço de base de pavimentos. Após esta etapa se iniciaram os ensaios de arrancamento nos solos, fornecendo parâmetros para a realização dos ensaios cíclicos. No arrancamento a areia apresentou ganho de resistência com o aumento da tensão confinante, e os maiores deslocamentos, já o silte e a brita não sofreram influência deste aumento. O comportamento cíclico causou desconfinamento da areia e degradação do reforço na brita, apresentando o comportamento mais estável no silte. Durante os ensaios o reforço apresentou grandes deformações conforme solicitado, o que contribuiu para os valores de módulos de resiliência abaixo dos descritos na literatura, que utiliza corpos de prova curtos e diferentes níveis de tensões. Nos ensaios cíclicos a areia variou seu módulo relativamente pouco com as variações de tensão confinante e cisalhante, o silte foi mais sensível à variação da cisalhante e a brita variou igualmente com as duas. / The behavior of reinforced soils depends largely on the interaction between soil and reinforcement, based on requests that the group will experience throughout its service life. Such interaction is commonly characterized by standardized tests such as the pullout, which seek to simulate the stresses to which the group is subject. However, some reinforced structures experience cyclic loads by considerable moving loads, that their behavior is hardly represented in these common tests. Thus, this research sought to improve the equipment of cyclic tests of the School of Engineering of São Carlos EESC-USP, in order to perform cyclic tests on different types of soil (one sand, clayey silt and a simple graded gravel), reinforced with one polyester geogrid commonly used for reinforcing pavements base. After this step began the pullout tests on soils, providing parameters for the realization of the cyclic tests. In the pullout tests, the sand had resistance gain with confining tension increasing and greater displacements, already silt and gravel not affected by this increase. The cyclical behavior caused deconfinement of sand, and the gravel causes degradation of reinforcement, with the more stable behavior on silt. During the test, the reinforce presented large deformations as requested, which contributed to the values of resilience modules below in the literature, which uses specimens shorter and different tension levels. In the cyclic tests the sand modulus varied relatively little with confining pressure and shear variations, the silt was more sensitive to the variation of shear and gravel also varied with both.
249

Análise da função de uma várzea na ciclagem de nitrogênio / Analysis of a floodplain\'s function in nitrogen cycling

Sidagis Galli, Corina Verónica 05 August 2003 (has links)
Para identificar a influência de uma área de várzea do ribeirão do Feijão (São Carlos-SP) sobre a ciclagem de nitrogênio e sobre a qualidade da água superficial e subsuperficial, foram analisadas as características físicas e químicas da água e determinadas as taxas de nitrificação e desnitrificação dos sedimentos da várzea. A maior concentração dos compostos nitrogenados foi observada na água de interface subsuperficial da várzea, região mais ativa em termos de fluxos de água e materiais. As taxas de nitrificação variaram de 0,145 a 0,068 &#956mol N-NO3-.g-1.dia-1 e a rota metabólica predominante foi a autotrófica, na qual as bactérias utilizaram amônio como substrato. As taxas de desnitrificação tiveram um valor médio de 0,0081 nmol N2O.g-1.dia-1. Mediante um modelo de estimativa foi calculado que 70% da água que circula no Ribeirão do Feijão provém do lençol que flui sob terras secas e o restante das áreas de várzea da bacia. Foi observado que existe uma considerável redução das concentrações dos compostos nitrogenados, principalmente do amônio, desde as zonas ripárias mais distantes do curso do rio até o canal, passando pela área de várzea. O funcionamento da várzea como sistema de filtro e depuração das águas subsuperficiais que alimentam o rio foi evidenciada pelas características físicas e químicas da água do rio em relação ao uso do solo na bacia. / In order to identify the influence of a floodplain area of the Feijão stream (São Carlos-SP) on surface and subsurface water quality, the physical and chemical characteristics of the water were analyzed and the floodplain sediment\'s nitrification and denitrification rates were determined. The highest concentration of nitrogen compounds was observed at the floodplain\'s subsurface water interface it being the most active region with respect to water and solute flow. Nitrification rates varied between 0.145 and 0.068 &#956mol N-NO3-.g-1.day-1 and the autotrophic metabolic route dominated, in which bacteria use ammonia as a substrate. Denitrification rate average was 0.0081 nmol N2O.g-1.day-1. Through a model it was estimated that 70% of the water flowing in the Feijão stream came from the water table flowing under dry land, the remainder coming from the floodplain of the area. A significant reduction of nitrogen compound concentration, mainly ammonium, was observed between the more distant riparian zones and the river\'s channel going through the floodplain. The floodplain\'s action as a filtering system for the water reaching the river was brought out through the physical and chemical characteristics of the river water relative to land use in the catchment area.
250

Desenvolvimento de um protótipo de sistema inteligente para análise da técnica de pedalada apresentada por ciclistas

Pigatto, André Vieira January 2018 (has links)
Este trabalho apresenta o desenvolvimento de um sistema inteligente para análise da técnica de pedalada aplicada por ciclistas. Para isso, desenvolveu-se um par de pedais de encaixe instrumentados, a partir dos quais é possível medir a componente de força normal aplicada nas partes frontal e posterior dos pedais. O modelo virtual da célula de carga experimental foi desenvolvido através da digitalização dos pedais de encaixe comerciais, utilizando-se um sistema comercial de escaneamento 3D com precisão declarada de 0,1mm. Cada pedal foi instrumentado com oito extensômetros de resistência elétrica (HBM 1-LY-13-1.5/350). Posteriormente os carregamentos máximos em cada eixo de medida de força foram estabelecidos utilizando-se uma plataforma de aquisição comercial específica para medida de deformação mecânica. Considerando-se os valores determinados, desenvolveu-se o circuito de condicionamento e realizaram-se os ensaios de deformação estática, obtendo-se as funções de transferência de saída de tensão elétrica em função do carregamento mecânico. O erro de linearidade máximo, considerando todos os canais, ficou abaixo de 0,75% e a máxima incerteza expandida (k=2) por canal, obtida através da aplicação do método clássico, foi de 1,55%. Em sequência, integrouse o sistema de pedais desenvolvido a dois outros sistemas, são eles: um par pedivelas experimentais instrumentados, capazes de medir as três componentes da força aplicada aos pedais e transmitidas aos pedivelas com um erro de linearidade abaixo de 0,6% e uma incerteza combinada inferior a 3,22%, e um sistema de cinemetria comercial, cuja precisão declarada pelo fabricante é de 1mm. Para possibilitar uma comparação quantitativa entre treinos ou ciclistas, implementou-se um sistema inteligente, baseado em redes Neuro-Fuzzy (ANFIS). A partir dos valores da potência média, do desvio padrão da potência e da assimetria bilateral média, obtidos ao longo de ensaios realizados sob protocolo desenvolvido especificamente para este trabalho, um score que representa o nível da técnica de pedalada apresentado pelo ciclista é determinado. Com intuito de testar o sistema, desenvolveu-se um projeto de experimentos com 2 fatores controláveis (sujeito e nível de frenagem de um rolo de treinamento), e realizou-se ensaios com oito ciclistas de características fisiológicas e níveis de preparos distintos. Através da análise estatística, constatou-se que das 23 variáveis de resposta consideradas ao longo do experimento, 23 são influenciadas significativamente pelo fator controlado sujeito e oito são influenciadas significativamente pelo fator controlado nível de frenagem magnética. / This report describes the development of an intelligent pedaling technique analysis system. To accomplish that, a pair of road bicycle pedals (SHIMANO R540) were instrumented to measure the forces that are applied to the front and back regions of the pedals. The virtual models of the pedals were developed based on a 3D scanned mesh developed with aid of a commercial 3D scanning system with a precision of 0.1mm. Each pedal was instrumented with eight electrical resistance strain-gages (HBM 1-LY-13-1.5/350). After that, the range of the mechanical deformation of each measurement channel was determined with aid of an industrial deformation acquisition system. The conditioning circuit was developed based on the mechanical deformation ranges previously determined and the static calibration experiment was performed to determine the voltage output transfer functions. The maximum linearity error determined per channel was 0,75% and the maximum expanded uncertainty (k=2), determined applying the classical methodology, was 1,55%. After that, the instrumented pedals developed were integrated with two complementary systems, which are: a pair of instrumented crank arm load cells which measure the components of the force applied to the bicycle pedal with a linearity error under 0.6% and an uncertainty of 3,22% and an Optitrack motion track system with a declared accuracy of 1mm. An intelligent pedaling technique analysis system was implemented through an Adaptive Neuro Fuzzy Inference System (ANFIS) to determine the cyclist pedaling technique score based on three inputs: the average power applied to bicycle pedal, the average power standard deviation and the bilateral asymmetry index, all of them collected under an experimental protocol specifically designed for this application. To evaluate the behavior of the system developed a randomized block experiment design with two controlled factors was performed indoor with aid of an ergometer roll; 160 sprints were conducted with eight subjects of different training levels. From the data collected an ANOVA test was performed, which confirmed that all the 23 response variables vary significantly in function of the subject’s controlled factor and eight of them vary significantly in function of the magnetic braking level.

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