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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.
161

Förbättrar intensiv träning prestationen hos motionärer?

Markinhuhta, Annelie January 2008 (has links)
<p>Syftet med den här studien är att undersöka huruvida en stor andel av intensiva grenspecifika pass utvecklade den aeroba kapaciteten hos motionärer som tränar inför Vasaloppet. Två testmetoder användes; ett maximalt laktattest på rullskidor utomhus och ett maximalt cykeltest på en cykelergometer inomhus. En utav fp genomförde ett tidstest på rullskidor på en given sträcka istället för laktattestet. Båda testerna genomfördes före och efter en 11-veckors träningsperiod som bestod av 41 procent medel- och högintensiva pass som genomfördes grenspecifikt. Det betyder intervaller på rullskidor eller i skidgång samt snabbdistanspass på rullskidor. Övriga 59 procent av träningspassen genomfördes på en lågintensiv nivå, vilket är mindre än de 70-80 procent som normalt förespråkas för en uthållighetsidrottare. 4 försökspersoner (fp) på motionsnivå deltog (4 män och 1 kvinna). Fp 3 förbättrade prestationen markant med 20 procent genom en minskning av blodlaktatkoncentrationer vid givna hjärtfrekvenser (HR), sålunda en förbättring av dels den aeroba laktattröskeln (LT) som den anaeroba laktattröskeln (AT). Fp 4 förbättrade prestationen med 15 procent genom att åka den givna sträckan under tidstestet på en snabbare tid vid andra tillfället. Fp 2 avverkade en 500m längre sträcka under andra rullskidtestet och förbättrade på så sätt sin prestation med 10 procent, fp fick dock en försämring av AT och hade högre blodlaktatkoncentrationer vid andra testtillfället. Fp 1 förbättrade LT men försämrade AT. Sammanfattningsvis, visar studien att ett 11-veckors träningsprogram bestående av mycket grenspecifik träning på högre intensiteter ledde till en klar prestationsförbättring hos två av fp, gällande alla parametrar som testades. De övriga två fp uppvisade vissa förbättringar men högre laktatkoncentrationer vid några mättillfällen.</p>
162

Effects of Environmental Water Vapor on Tropical Cyclone Structure and Intensity

Ortt, Derek 01 January 2007 (has links)
The tropical cyclone (TC) and environmental interaction is not fully understood. Previous studies have demonstrated that this interaction affects intensity change. The studies found that intensification is favored in low shear, moist environments, with high sea surface temperatures (SST). However, little precise quantification was provided, especially in terms of the impact of environmental water vapor on TC intensity change. This work addresses the TC interaction with the environmental water vapor. Results from a comprehensive statistical study show that TC intensification is more likely to occur in an anomalously moist environment than a dry environment. However, only a small amount of the total variance is explained. When assessing the effect of vertical wind shear along with environmental water vapor, more of the variance is explained. Water vapor not only affects TC intensity. Prior modeling studies have demonstrated impacts from environmental water vapor on TC structure. These impacts can also affect intensity change. Specifically, enhanced water vapor content within the TC enhances the rainbands, which can lead to an eyewall replacement cycle, causing a temporary weakening, followed by re-intensification. This thesis evaluates observational and high resolution MM5 model output from Hurricanes Katrina and Rita from the Hurricane Rainband and Intensity Experiment (RAINEX) to evaluate the effects of varying water vapor distributions on TC structure. While the two hurricanes were of similar intensity, they had different water vapor distributions and structures. Rita underwent an eyewall replacement cycle while under RAINEX surveillance while Katrina did not. Rita was also located within a dry environment and had a strong horizontal moisture gradient, while Katrina was in a moist environment and had a weak moisture gradient. Results suggest that a strong horizontal water vapor gradient, with a moist TC and dry outer environment may confine the hurricanes into a pattern that causes them to have high circularity, promoting the formation of a secondary eyewall. The dry outer environment had strong atmospheric stability and was less favorable for deep convection far from the center in the Rita case. The moist environment in the Katrina case was more unstable. This may have allowed for the rainbands to be farther from the center in a less circular pattern than Rita. The results presented in this thesis suggest that this pattern is less favorable for an eyewall replacement cycle.
163

Impact of Assimilating Airborne Doppler Radar Winds on the Inner-Core Structure and Intensity of Hurricane Ike (2008)

Gordon, Ronald Walter 26 July 2011 (has links)
Accurate prediction of Tropical Cyclones (TC) is vital for the protection of life and property in areas that are prone to their destructive forces. While significant improvements have been made in forecasting TC track, intensity remains a challenge. It is hypothesized that accurate TC intensity forecast requires, among other things, an adequate initial description of their inner-core region. Therefore, there must be reliable observations of the inner-core area of the TC and effective data assimilation (DA) methods to ingest these data into the Numerical Weather Prediction (NWP) models. However, these requirements are seldom met at the relatively low resolution of operational global prediction models and the lack of routine observations assimilated in the TC inner-core. This study tests the impacts of assimilating inner-core Airborne Doppler Radar (ADR) winds on the initial structure and subsequent intensity forecast of Hurricane Ike (2008). The 4-dimensional variational (4DVar) and the 3-dimensional variational (3DVar) methods are used to perform DA while the Weather Research and Forecasting (WRF) model is used to perform forecasts. It is found that assimilating data helps to initialize a more realistic inner-core structure using both DA methods. Additionally, the resulting short-term and long-term intensity forecasts are more accurate when data is assimilated versus cases when there is no DA. Additionally, it is found that in some cases the impact of DA lasts up to 12 hours longer with 4DVar versus 3DVar. It is shown that this is because the flow-dependent 4DVar method produces more dynamically and balanced analysis increments compared to the static and isotropic increments of 3DVar. However, the impact of using both methods is minimal in the long-range. The analyses show that at longer forecast range the dynamics of hurricane Ike was influenced more by outer environment features than the inner-core winds.
164

Förbättrar intensiv träning prestationen hos motionärer?

Markinhuhta, Annelie January 2008 (has links)
Syftet med den här studien är att undersöka huruvida en stor andel av intensiva grenspecifika pass utvecklade den aeroba kapaciteten hos motionärer som tränar inför Vasaloppet. Två testmetoder användes; ett maximalt laktattest på rullskidor utomhus och ett maximalt cykeltest på en cykelergometer inomhus. En utav fp genomförde ett tidstest på rullskidor på en given sträcka istället för laktattestet. Båda testerna genomfördes före och efter en 11-veckors träningsperiod som bestod av 41 procent medel- och högintensiva pass som genomfördes grenspecifikt. Det betyder intervaller på rullskidor eller i skidgång samt snabbdistanspass på rullskidor. Övriga 59 procent av träningspassen genomfördes på en lågintensiv nivå, vilket är mindre än de 70-80 procent som normalt förespråkas för en uthållighetsidrottare. 4 försökspersoner (fp) på motionsnivå deltog (4 män och 1 kvinna). Fp 3 förbättrade prestationen markant med 20 procent genom en minskning av blodlaktatkoncentrationer vid givna hjärtfrekvenser (HR), sålunda en förbättring av dels den aeroba laktattröskeln (LT) som den anaeroba laktattröskeln (AT). Fp 4 förbättrade prestationen med 15 procent genom att åka den givna sträckan under tidstestet på en snabbare tid vid andra tillfället. Fp 2 avverkade en 500m längre sträcka under andra rullskidtestet och förbättrade på så sätt sin prestation med 10 procent, fp fick dock en försämring av AT och hade högre blodlaktatkoncentrationer vid andra testtillfället. Fp 1 förbättrade LT men försämrade AT. Sammanfattningsvis, visar studien att ett 11-veckors träningsprogram bestående av mycket grenspecifik träning på högre intensiteter ledde till en klar prestationsförbättring hos två av fp, gällande alla parametrar som testades. De övriga två fp uppvisade vissa förbättringar men högre laktatkoncentrationer vid några mättillfällen.
165

THE EFFICACY OF LENTILS AS A PRE-EXERCISE MEAL FOR ATHLETES OF HIGH INTENSITY SOCCER-SPECIFIC INTERMITTENT EXERCISE

2013 March 1900 (has links)
This work examined lentils as an optimal and acceptable pre-exercise meal for athletes of high intensity intermittent exercise. Thirteen male athletes participated in 4 simulated soccer trials with a repeated-measures crossover design. Along with a fasted control condition, isocaloric lentil, potato & egg white, or potato meals providing 1.5 g total carbohydrate/kg were consumed 2-h before the trials. Pre-exercise meal sensory acceptability and digestive tolerability were measured throughout testing with fixed-point scales: A sensory test meal analysis and gastrointestinal digestive symptom rating scale. Participant demographics, nutrition knowledge, and psychosocial perceptions towards lentils were assessed with a questionnaire. Distance covered on a 5 x 1 min repeated sprint test (2.5 min rest) at the end of the soccer trial assessed exercise performance. The Borg Scale (0-20) determined ratings of perceived exertion during exercise testing. Barriers toward pulse-based meal consumption negatively correlated with weekly pulse consumption (r=-0.902, p <0.05), while a positive correlation existed between beneficial beliefs of pulse-based meal consumption and weekly pulse consumption (r=0.620, p <0.05). Participants consumed an average of 79.5 ± 1.8% of each meal. The meals were perceived large in size and cumbersome to ingest by the participants, and no between meal differences were observed (p>0.05). The lentil meal was not as appealing in aroma, appearance, or flavour compared to the potato meal, but no different than the potato & egg meal (p>0.05). Lentil consumption resulted in a minimal increase in nausea compared to the other conditions (1.0, 0.54, 0.31 and 0.08, for lentil, potato & egg, potato, and control, respectively, p<0.05). Initially after consumption, all meals resulted in more bloating and fullness, and less hunger than control (p<0.05). Improved overall exercise performance was proportional with greater pre-exercise meal energy (r = 0.68, p <0.05) and carbohydrate intake (r = 0.67, p<0.05). Pre–exercise consumption of the low glycemic index lentil meal, as well as the two high glycemic pre-exercise meals, resulted in improved total sprint distances compared to the fasted control condition (p<0.05). The comparative sensory acceptability, digestive tolerability and similar performance outcomes of the lentil meal to the other pre-exercise meals indicates lentils may be a suitable pre-exercise meal for athletes of high intensity intermittent exercise.
166

Photon flux monitor for a mono-energetic gamma ray source

Mavrichi, Octavian 25 March 2010
A novel photon flux monitor has been designed and tested for use at the Duke University High Intensity Gamma Source, where the photon beam produced is essentially mono-energetic but it is not tagged. Direct counting of the number of photons using a high-efficiency detector is not possible because of the high photon fluxes expected. Therefore, a direct counting detector with a low, accurately known efficiency was required.<p> The photon flux monitor based on a five scintillator paddle system detects recoil electrons and positrons from photoelectric, Compton and pair-production processes. It has been designed to be insensitive to gain and detector threshold changes and to be usable for photon energies above 5 MeV. It has been calibrated using direct counting with a NaI detector and its efficiency has been shown to be well predicted by a GEANT4 simulation.<p> Results of measurements, calibration and calculations required to characterize the 5-paddle photon flux monitor are presented. The photon flux monitor has met its design specifications of being able to determine the number of photons incident on it during the live time of a measurement to within a systematic error of 2%.<p> A paper based on the work for this thesis has been published in the Nuclear Instruments and Methods in Physics Research Journal.
167

Model study of the hydraulics related to fish passage through embedded culverts

Garner, Megan 21 April 2011
Corrugated steel pipe (CSP) culverts are widely used as an economical alternative for conveying streams and small rivers through road embankments. While passage of the design flow is generally the primary goal for culvert design, consideration must also be given to maintaining connectivity within the aquatic environment for fish and other aquatic organisms. In Canada, the design criteria for fish passage through culverts are generally specified in terms of a maximum mean flow velocity corresponding to the weakest swimming fish expected to be found at a specific location. Studies have shown, however, that the velocity distribution within a CSP culvert may provide sufficient areas of lower velocity flow near the culvert boundary to allow for fish passage, even when the mean flow velocity may exceed a fishs swimming ability. Improved knowledge of the hydraulic conditions within CSP culverts, combined with research into fish swimming capabilities and preferences, may make it possible to better tailor culvert designs for fish passage while at the same time decreasing construction costs. To meet the requirements of regulators, various measures may be taken to reduce culvert flow velocities. Embedding, or setting the invert of a culvert below the normal stream bed elevation, is a simple and inexpensive method of increasing the flow area in a culvert flowing partially full, thereby decreasing flow velocity. Fish traversing through an embedded culvert benefit not only in terms of lower mean flow velocities, but also even lower flow velocities in the near boundary region. In the province of Saskatchewan culvert embedment is regularly used as a means to improve fish passage conditions. In this study, a laboratory scale model was used to study the velocity distribution within a non-embedded and embedded CSP culvert. An acoustic Doppler velocimeter was used to measure point velocities throughout the flow cross section at several longitudinal locations along the culvert. The hydraulic conditions were varied by changing the discharge, culvert slope and depth of embedment. The point velocity data were analyzed to determine patterns of velocity and turbulence intensity at each cross section, as well as along the length of the culvert. The results from the embedded culvert tests were compared with the results from the equivalent non-embedded tests, so that initial conclusions could be made regarding the use of embedment to improve conditions for fish passage. Analysis of the cross section velocity distributions showed that, even the non-embedded culvert had a significant portion of the flow area with flow velocity less than the mean velocity. The results from the embedded tests confirmed that embedding the culvert reduced the flow velocity throughout each cross section, although the effect was most significant for the cross sections located greater than one culvert diameter downstream from the inlet. This variation in effectiveness of embedment at reducing flow velocities is attributed to the length of the M1 backwater profile relative to the culvert length, and thus the differential increase in flow depth that occurred at each measurement location along the culvert. For both the non-embedded and embedded culvert the peak point magnitudes of turbulence intensity were found to be located near the culvert inlet where the flow was contracting. In terms of the cross section average turbulence intensity, in the non-embedded culvert turbulence increased with distance downstream from the inlet and was highest at the cross sections located near the culvert outlet. Embedding the culvert was found to either have no impact, or to slightly increase, the cross section average turbulence intensity near the inlet. Again, a result that is attributed to the tapering out of the M1 backwater profile at locations near the inlet under the flow conditions tested. However, beyond eight culvert diameters downstream from the inlet, embedment did result in lower cross section average turbulence intensity when compared to the non-embedded culvert. The measured velocity profiles for the non-embedded tests were found to compare well to the theoretical log-law velocity distribution using a ks value of between 0.012 m and 0.022 m, or approximately one to two times the corrugation amplitude, when the datum for analysis was considered to be located at the crest of the pipe corrugation. The cross section velocity distributions for the non-embedded tests compared very well to the model proposed by Ead et al. (2000). Based on this assessment, it appears that the Ead et al. model is potentially suitable for use in predicting the amount of the cross sectional area in a non-embedded culvert with flow velocity less than the design target for culvert fish passage design purposes. Overall, the results of the study confirm that, embedding a CSP culvert may be an effective way to improve fish passage conditions in terms of both flow velocity and turbulence intensity.
168

Adaptive and Robust Radiation Therapy Optimization for Lung Cancer

Misic, Velibor 23 July 2012 (has links)
A previous approach to robust intensity-modulated radiation therapy (IMRT) treatment planning for moving tumours in the lung involves solving a single planning problem before treatment and using the resulting solution in all of the subsequent treatment sessions. In this thesis, we develop two adaptive robust IMRT optimization approaches for lung cancer, which involve using information gathered in prior treatment sessions to guide the reoptimization of the treatment for the next session. The first method is based on updating an estimate of the uncertain effect, while the second is based on additionally updating the dose requirements to account for prior errors in dose. We present computational results using real patient data for both methods and an asymptotic analysis for the first method. Through these results, we show that both methods lead to improvements in the final dose distribution over the traditional robust approach, but differ greatly in their daily dose performance.
169

Adaptive and Robust Radiation Therapy Optimization for Lung Cancer

Misic, Velibor 23 July 2012 (has links)
A previous approach to robust intensity-modulated radiation therapy (IMRT) treatment planning for moving tumours in the lung involves solving a single planning problem before treatment and using the resulting solution in all of the subsequent treatment sessions. In this thesis, we develop two adaptive robust IMRT optimization approaches for lung cancer, which involve using information gathered in prior treatment sessions to guide the reoptimization of the treatment for the next session. The first method is based on updating an estimate of the uncertain effect, while the second is based on additionally updating the dose requirements to account for prior errors in dose. We present computational results using real patient data for both methods and an asymptotic analysis for the first method. Through these results, we show that both methods lead to improvements in the final dose distribution over the traditional robust approach, but differ greatly in their daily dose performance.
170

Biokinetic behaviour of <i>Chlorella vulgaris</i> in a continuous stirred bioreactor and a novel circulating loop photobioreactor

Sasi, Divya 21 September 2009
Capture of CO2 by algae is an important mechanism for removal of this greenhouse gas from the atmosphere. For this reason, <i>Chlorella vulgaris</i> has beeen studied extensively over the years. A high growth rate of the microalgae is essential in order to increase the fixation rate of CO2 through photosynthesis. Though a number of studies have been carried out to optimize growth of <i>C. vulgaris</i>, high growth rates have not been achieved (Kleinheinz & Keffer, 2002).<p> In this study, a novel circulating loop photobioreactor with enhanced light distribution, gas mass transfer rate and mixing properties was used for the biokinetic study of <i>C. vulgaris</i>. The objective was to study individual effects of light intensity and CO2 concentration on the specific growth rate of <i>C. vulgaris</i>. Studies in this photobioreactor could generate high growth rates of 0.043 h-1. The effect of light intensity on the growth of the <i>C. vulgaris</i> was determined by varying intensity of light to the photobioreactor within a range of 26.945 mW to 431.128 mW, while the flow of air and CO2 were held constant. An increase in light intensity to the photobioreactor resulted in an increase in cell density and variation in the chlorophyll content of the <i>C. vulgaris</i> cells. Enhanced growth rates of <i>C. vulgaris</i> cells in this novel circulating loop photobioreactor could be attributed to the combined effect of the CO2 concentration and the uniform distribution of light throughout the reactor volume.<p> Interacting effects of dilution rate, light intensity and concentration of carbon dioxide on specific growth rate was studied in an externally illuminated, continuous flow stirred bioreactor. Steady flow of nutrient medium and air flow was maintained in the bioreactor. This study proved that the dilution rate has major significance at high concentrations of CO2 and high intensities of light. At high concentrations of CO2 at 10% (v/v) and 15% (v/v), increasing dilution rate from 0.005 h-1 to 0.01 h-1 could result in increasing growth rate by a factor of 1.45 and 2.16 respectively.

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