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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.
131

Eficiência da braçada no nado crawl : atualização do estado da arte / The arm stroke efficiency in front crawl swimming : updating the state of the art

Silveira, 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.
132

Water-use efficiency and productivity in native Canadian populations of Populus trichocarpa and Populus balsamifera

Pointeau, Virginie M. 05 1900 (has links)
Afforestation and reforestation programs utilizing available fields for biofuel production, carbon sequestration, and other uses linked to climate change are looking to tree physiologists to identify species and genotypes best-suited to their purposes. The ideal poplar genotype for use in Canadian programs would be drought-resistant, cold-climate adapted, and fast-growing, thus requiring an understanding of links between a variety of physiological traits linked to growth and productivity. This study examined the basis for variations in water-use efficiency within four selected populations of Populus trichocarpa and Populus balsamifera (2 provenances each). Each species included both a northern and a southern provenance. Correlations between water-use efficiency, nitrogen-use efficiency, ¹³C/¹²C isotope ratio, stomatal conductance, and overall productivity were evaluated. Gas exchange variables measured included net photosynthesis, transpiration rate, stomatal conductance, and intercellular CO₂ content. Water-use efficiency and ¹³C content across all genotypes were highly correlated. Results suggested that variation in water-use efficiency was primarily related to variation in stomatal conductance across all genotypes. Whereas differences in net photosynthesis in this study were not significant between species, P. balsamifera did reveal a higher average stem volume overall. Although variation in stomatal conductance was the major determinant of differences in water-use efficiency, positive correlations were found between ¹³C isotope abundance and net photosynthesis in both P. balsamifera provenances. In this regard, results for the northern P. balsamifera provenance are the most consistent across all gas-exchange and growth trait correlations, in terms of meeting expectations for sink-driven water-use efficiency. The findings in this study suggest the possibility of identifying poplar genotypes with an absence of trade-off between water-use efficiency and nitrogen-use efficiency, notably among genotypes from the northern P. balsamifera provenance, near Gillam. / Forestry, Faculty of / Graduate
133

EVALUATION OF SPECTRAL Vs ENERGY EFFICIENCY TRADEOFF CONSIDERING TRANSMISSION RELIABILITY IN CELLULAR NETWORKS

Kassa, Hailu Belay, Engda, Tewelgn Kebede, Menta, Estifanos Yohannes 11 1900 (has links)
Spectral efficiency (SE), energy efficiency (EE), and transmission reliability are basic parameters to measure the performance of a cellular network. In this paper, spectral efficiency and energy efficiency tradeoff is considered keeping in mind the transmission reliability, where all the three are function of signal to noise ratio (SNR). SNR, in turn is a function of constellation size (or the number of bits per symbol) and data rate. Then, we propose a new power model which is as function of this SNR. Based on the power model, SE-EE trade-off function is evaluated taking transmission reliability in to consideration. Results confirmed that increasing constellation size results an increase in SNR and leads to a significant increase in energy efficiency without changing the transmit power. To demonstrate the validity of our analysis, channel gain and constellation size are varied keeping transmit power constant. The results also indicate that securing transmission reliability, the EE-SE trade-off is optimized by increasing the constellation size.
134

A comparison of the effects of carbohydrate and fat as energy sources in trout and chick diets on tissue glycogen concentration and on the rate of glycogen depletion from the tissues during a subsequent period of fast

Hickling, David Robert January 1981 (has links)
Rainbow trout, about one-year-old, were fed diets containing either glucose (C) or herring oil (F) as the non-protein energy source for a period of two weeks. As well, they were fed each diet at satiation (C-2, F-2) and at levels half that (C-l, F-l). The trout were subsequently fasted and sampled for tissue glycogen, protein, dry matter and glucose-6-phosphatase activity at full feeding and at 2, 4, 8, 10, 13 and 16 days of fasting. The livers of the C-fed fish had 12% wet weight glycogen and the livers of the F-fed fish had 3% wet weight glycogen at full feeding. Upon fasting, glycogen concentrations in the F-fed fish livers fell to basal levels of 1% by 2 days while glycogen concentrations in the C-fed fish livers fell to basal levels only after 10 days. The protein concentration in the trout livers was inversely related to the glycogen concentration. The amount of liver protein in the trout carcass, however, was directly related to dietary carbohydrate levels. Trout liver glucose-6-phosphatase activity increased as fasting progressed but there were no treatment differences in enzyme activity. The muscle of the C-2 fed trout contained .4% glycogen at full feeding. The muscle of the other dietary treatments contained .1-.15% glycogen. It appears that trout muscle stored dietary carbohydrate that was not taken up by the liver or that was not oxidized. Upon fasting there was a depletion in muscle glycogen to basal levels of .05% after 4 days. Thereafter there occurred a rebound in muscle glycogen to levels at or greater than full-fed levels followed by a decline back to basal values. The rebound was greater and peaked earlier (8 days) in the C-fed trout than in the F-fed trout (10 days). Broiler (BR) and White Leghorn (WL) pullet chicks were fed diets, where 25% of the energy was supplied as corn starch (C) or corn oil (F), for a three-week period. The chicks were then fasted and sampled for tissue glycogen, protein and dry matter at full feeding and at 8, 16, 24, 32, 44, 56, 80, 104 and 128 hours of fasting. The BR livers contained more glycogen (3%) than the WL livers (2%) and the C-fed chicks had greater liver glycogen concentrations (3%) than the F-fed chicks (2%) at full feeding. Upon fasting, liver glycogen fell to basal levels of .03% after 8 hours. Thereafter there was a rebound increase in liver glycogen levels to a peak of 1% and a subsequent tapering off. The rebound occurred earlier in the C-fed chicks than in the F-fed chicks. The peak was attained earlier in the WL (32-44 hours) than in the BR (50 hours). The amount of liver protein in the C-fed chicks was higher than that in the F-fed chicks over the entire fasting period. Chick muscle glycogen concentrations were initially higher in the C-fed than in the F-fed chicks and higher in BR (1.2%) than in WL (.8%). Upon fasting, BR muscle glycogen concentrations were maintained while those of WL fell to .3%. There were erratic fluctuations in muscle glycogen levels. / Land and Food Systems, Faculty of / Graduate
135

Continued Development of a Chilled Water System Analysis Tool for Energy Conservation Measures Evaluation

Gaudani, Ghanshyam 01 January 2013 (has links) (PDF)
Chilled water systems constitute a major portion of energy consumption in air conditioning systems of commercial buildings and process cooling of manufacturing plants. These systems do not operate optimally in most of the cases because of the operating parameters set and/or the components used. A Chilled water system analysis tool software (CWSAT) is developed as a primary screening tool for energy evaluation. This tool quantifies the energy usage of the various chilled water systems and typical measures that can be applied to these systems to conserve energy. The tool requires minimum number of inputs to analyze the component-wise energy consumption and incurred overall cost. This thesis also examines various energy conservation measures that are available for chilled water systems. The components, arrangements, and the common energy conservation opportunities for chilled water systems are presented. The new version of the tool is developed in Object Oriented Programming Language Microsoft Visual Basic.Net© to maintain the tool latest with current technology, add and expand capabilities and avoid obsolescence. Many Improvements to the previous tool are made to improve quality and the types of the systems the tool can handle. The development of the new routines and interfaces is also accommodated in the new version to make the tool universal. In order to determine the accuracy of the new version of the tool, a comparison is made between the results from the previous and new version of the tool. The results of the comparisons are presented.
136

Rural road quality, farm efficiency and income in Ethiopia. Development working papers series 3. Working paper No. 01/15

Wondemu, Kifle Asfaw 06 1900 (has links)
yes / Small scale farmers in Ethiopia are already operating on their land frontier and the scope for an increase in production and rural income should come, among others, through improvement in technical and allocative efficiency. Although the stake of efficiency improvement is substantial, a number of empirical studies undertaken to identify the determinants of efficiency however are few. Moreover, although road infrastructure is among key public goods that significantly influences the farm level economic efficiency, empirical studies that have considered its role in farm efficiency analysis is scarce. This research investigated the link between the quality of rural road and farm level allocative and technical efficiency as well as the impact of inefficiency on farm income. The result showed that households that have all weather road access are 16% technically and two times allocatively more efficient. Both allocative and technical inefficiencies reduce income; the adverse impact of technical inefficiency on income however is stronger. Although household specific factors have contributed to the observed inefficiencyin most cases it is exogenously driven, namely, it is a rational response to market imperfection and risks. Interventions that reduce market and production risks will increase crop output and farm income.
137

Variation among grain sorghum genotypes in response to nitrogen fertilizer

Mahama, George Yakubu January 1900 (has links)
Master of Science / Department of Agronomy / P.V. Vara Prasad / Grain sorghum [Sorghum bicolor (L.) Moench] is an important crop in the semi-arid regions of Africa, Asia and United States. Productivity of grain sorghum is limited by soil fertility, especially nitrogen (N). Sorghum genotypes are known to vary in their response to nitrogen, however, the information on nitrogen use efficiency (NUE) is limited. The objectives of this research were to (a) determine the response of sorghum genotypes (hybrids and inbred lines) to nitrogen fertilizer (b) quantify genotypic differences in NUE; and (c) determine physiological and morphological basis of NUE. Field experiments were conducted at three locations in Kansas (Hays, Ottawa and Manhattan) during 2010 and 2011. Six hybrids and six inbred lines of grain sorghum were grown with 0, 45 and 90 kg N ha-1.The experimental design was a split-plot design with N regimes as main plots and genotypes as sub-plot, with four replications. Planting was done in May and June across all the locations, and nitrogen fertilizer (Urea, 46% N) was applied at emergence. Data on N concentration in the leaves, stems and grain were determined. NUE and components of N use were computed for Ottawa and Manhattan as follows: Nitrogen use efficiency (NUE): Grain weight / N supplied; Nitrogen utilization efficiency: Grain weight / N total in plant; Nitrogen uptake efficiency: N total in plant / N supplied; Percent fertilizer recovery = [uptake (fertilized plot) – N uptake (un- fertilized plot)] / [ N applied ] x 100; and Nitrogen harvest index (NHI) = Grain N / N total in plant. Where N supplied = Rate of N fertilizer applied + soil N supplied. Growth and yield data were collected at all locations. There were significant effects of genotypes (P < 0.05) and nitrogen (P < 0.05) on biomass and grain yield across all locations. Performance of hybrids was generally superior to the inbred lines of all traits. Sorghum hybrids 26506 and 99480 produced maximum grain yield across all locations. While inbred lines B35 and SC35 had the lowest grain yield. Maximum biomass and grain yield was obtained at 90 kg N ha-1, followed 45 kg N ha-1, and lowest in 0 N kg ha-1. There were significant differences among genotypes for all NUE traits at Ottawa and Manhattan. Across genotypes, total NUE ranged from 17.2 to 42.6 kg kg-1, utilization efficiency from 24.3 to 60.2 kg kg-1, N uptake efficiency ranged from 56.1 to 82.5%, recovery from 2 to 52%, and NHI from 43.6 to 81.3%. Among the genotypes, 99480 and 26506 both known to be post–flowering drought tolerance were high in NUE and component of N use. While genotypes B35 and SC35 were the lowest in NUE and components of N use. Overall, our data suggest that there were significant differences for NUE traits in sorghum hybrids and inbred lines. There are opportunities to breed for higher NUE in grain sorghum.
138

OPTIMAL LINEAR DETECTION OF SOQPSK

Geoghegan, Mark 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / Shaped Offset QPSK (SOQPSK), as proposed and analyzed by Terrance Hill, is a family of constant envelope waveforms that is non-proprietary and exhibits excellent spectral containment and detection efficiency. Detection results using the filtering found in conventional OQPSK demodulators have been published for two variants of SOQPSK, namely SOQPSK-A and –B. This paper describes a method of synthesizing an optimal linear detection filter, with regard to bit error probability (BEP), and presents the resulting performance.
139

An analysis of ways to maximize the efficiency of the NEPA environmental process at the Texas Department of Housing and Community Affairs

Ramphul, Ryan Christian 15 November 2010 (has links)
In light of the substantial sums of money that the Texas Department of Housing and Community Affairs (TDHCA) was awarded through the American Recovery and Reinvestment Act of 2009, ways to maximize the efficiency of the agency’s various processes are highly sought after. The TDHCA environmental review process, which is required by the National Environmental Policy Act (NEPA), is one of the longest processes that people applying for federal funding through TDHCA must face. It is, therefore, a process that would substantially benefit the agency by being made more efficient. In this report, areas where applicants find the TDHCA environmental process to be difficult are illustrated by a systematic tabulation of the deficiency reviews sent to a sample of applicants from 2009. Additionally, survey data collected from people who submit environmental applications, and also people who review environmental applications, provides quantitative data about specific areas of the process where applicants meet with difficulty; and also qualitative data about where survey-takers feel the process could be made easier and more efficient. The data seems to indicate that applicants have significant difficulty knowing how to start the environmental process, the documents necessary, and how to fill out the necessary documents. In terms of suggestions, the results indicate that a more elaborate, user-friendly environmental webpage, complete with examples of required documents, and examples of how to fill them out, would make the environmental process exponentially easier for applicants. With the process being easier for applicants, TDHCA Environmental Specialists will hopefully not need to send out as many deficiency reviews to applicants, and will instead be able to review applications faster and issue environmental clearance quicker; thus making the process more efficient. / text
140

The properties of revision of earnings forecasts by financial analysts : Canadian evidence

Hennessey, Sean Michael January 1993 (has links)
No description available.

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