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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

Intramolecular Isotope Effects for the Study of Reactions with MassTransfer Limitations

Wagner, Joshua G. 16 January 2010 (has links)
The research presented provides a method to use the comparison of intermolecular isotope effects vs. the intramolecular isotope effects for the study of reactions in which study of the rate limiting step is ambiguous due to interfering mass transfer effects. The oxidation of unfunctionalized hydrocarbons at mild conditions developed by Sir Derek Barton, the Gif reaction is the model used. The history is provided to demonstrate the relevance of using this model as one which could show the usefulness of this method. Evidence has been provided and used to theorize that the rate limiting step of the reaction may be diffusion of the reactants, not a chemical change. Starting materials were made which would allow for the measurement for both the intermolecular and intramolecular KIE and those values were compared. The results show that there is little difference between the intermolecular and intramolecular KIE, therefore the reaction is not diffusion controlled.
2

Intramolecular Isotope Effects for the Study of Reactions with MassTransfer Limitations

Wagner, Joshua G. 16 January 2010 (has links)
The research presented provides a method to use the comparison of intermolecular isotope effects vs. the intramolecular isotope effects for the study of reactions in which study of the rate limiting step is ambiguous due to interfering mass transfer effects. The oxidation of unfunctionalized hydrocarbons at mild conditions developed by Sir Derek Barton, the Gif reaction is the model used. The history is provided to demonstrate the relevance of using this model as one which could show the usefulness of this method. Evidence has been provided and used to theorize that the rate limiting step of the reaction may be diffusion of the reactants, not a chemical change. Starting materials were made which would allow for the measurement for both the intermolecular and intramolecular KIE and those values were compared. The results show that there is little difference between the intermolecular and intramolecular KIE, therefore the reaction is not diffusion controlled.
3

Photoelectromagnetic effect in semiconductors

Urli, Natko B. January 1900 (has links)
Thesis (M.S.)--University of Michigan, 1963. / Degree awarded Dec. 1963. Project completed May 1964.
4

Effects of Cadmium on Morphology, Photosynthesis and Protein Profile of Bean Plants

Pournia, Farnaz 14 March 2009 (has links)
Cadmium (Cd), a cancer-causing heavy metal ion, concentration in the environment has recently shown a rapid increase mainly as a result of human activity. Since many plants are used as medicine and food, it is crucial to investigate effects of Cd on plant growth and development. This study examines the time course and concentration-dependent effects of Cd on morphology, photosynthesis and protein profiles in hydroponically-grown bean plants (Phaseolus vulgaris). High concentrations of Cd (1000 and 100uM) induced leaf wilting and reduced both leaf growth and photosynthesis rate within 24 and 48 hours respectively. Lower concentration of 10 uM Cd showed the wilted morphology after 96 hours. In addition, the Cd-induced changes in protein profiles especially the photosynthesis and stress proteins will be discussed in relation to morphology, leaf growth and photosynthesis in bean plants.
5

The Effectiveness of Special Effects: Practical Effects vs. Digital Effects

Ciccone, Vanessa 27 October 2016 (has links)
For centuries films have given filmmakers the ability to affect their audiences visually and emotionally. Special effects and digital effects make a fictional scene appear more realistic. In the film An American Werewolf in London, make-up artist Rick Baker revolutionized the use of practical effects when transforming David Naughton’s character into a werewolf. In 1997 when An American Werewolf in Paris was released, director Anthony Waller utilized digital effects, instead of practical effects, when transforming various characters into werewolves. These transformation scenes were not met with as much praise as its predecessor. If we were to have a better understanding of how individuals perceive practical effects and digital effects it would allow us to determine which one better conveys an emotional reaction. This thesis will demonstrate which type of special effect, practical effects or digital effects, is more effective at relaying an emotional response in a viewer.
6

An investigation into the effect of maternal exposure to nicotine and copper on neonatal lung development.

Windvogel, Shantal Lynn January 2006 (has links)
<p>In the 20th century, where tobacco smoking continues to be the leading preventable cause of death, an alarming number of people continue to smoke, despite awareness of the implications of exposure for themselves and those around them. Campaigns for the promotion of effective tobacco legislation and awareness are continuously being confronted by the tobacco industry's reluctance to put the health of their consumers before company profits, leading to a ripple effect of misinformation, serious health risks and economic implications, at least for the consumers. Pregnant women are especially a concern, because exposure to tobacco smoke affects not only the smoking mother but has serious implications for the health of her unborn child. Therefore, the aim of this study was to investigate the effect of maternal exposure to nicotine during all the phases of lung development, or from the onset of the phase of rapid alveolarisation and, whether copper supplementation will prevent the adverse effects of maternal nicotine exposure, on lung development in the offspring.</p>
7

Alcohol and other drugs: prevalence, demographic characteristics and perceived effects on the academic performance of high school students within the Mogalakwena Municipality of Limpopo Province.

Owo, Owo Ikwa 04 March 2013 (has links)
INTRODUCTION: Smoking, alcohol and other drugs use among high school learners has become a major public health problem across the globe. Here in South Africa, it is estimated that a large proportion of learners indulge in smoking and the use of alcohol and illicit drugs. Data from treatment sites across the country indicate that the number of patients who are below 20 years seeking treatment is escalating. These indulgences have been blamed for escalating school violence, rapes, robbery and accidents, all of which contribute to increased morbidity, disability and premature deaths. It is expected that the result of this study may provide additional understanding about learners’ drug and alcohol use. Such additional understanding can be of benefit to those responsible for the planning and implementation of cessation programmes. AIM AND OBJECTIVES: To determine the extent of drug and alcohol use, the relationship between substance use and academic performance, and the factors that may influence cessation of alcohol and drug use among high school learners in Mogalakwena municipality. METHOD: The protocol involved purposeful selection of one school from each of the nine education circuits within the Mogalakwena Municipality, Limpopo Province. The questionnaire was anonymous, requiring no data that can identify any learners. The sample consisted of five hundred and fifty five students aged 15 to 23(53% females and 47% males). The data was coded and analysed with epi-info version 6(Dutch) and this involved descriptive statistics and cross tabulations with specific reference to chi square test and students t-test yielding p-values. RESULTS: The result of this study indicate that among high school learners in the Mogalakwena municipality 28% have smoked cigarette, 65% have drunk alcohol and 16% have used illicit drugs.In addition there was statistically significant difference between urban and rural learners in terms of smoking and alcohol consumption, with higher rates among urban students, but there was no difference in the use of drugs between the two groups. Also, there was statistically significant difference in drug usage and smoking with regard to age but no difference in alcohol consumption. Younger students tended to smoke more and also were more involved in the use of drugs. More males than females were involved in smoking, alcohol consumption and drugs use. The most reported factors that could influence cessation of alcohol and drugs use were bad effect 49%, cost 23% and parents’ influence 15%. Among the parameters examined as proxies for impact of alcohol and other drugs use on academic performance, indications point to negative impact. CONCLUSION: Alcohol and other drugs use is prevalent among high school learners in the Mogalakwena municipality and is reported to have a negative impact on academic performance. “Bad effects”, high costs and significant relationships are reported as the most important factors that could influence alcohol and other drugs use cessation and these may be important considerations in planning risk reduction.
8

Kinetic isotope effects, dynamic effects, and mechanistic studies of organic reactions

Wang, Zhihong 25 April 2007 (has links)
Several organic reactions that could potentially involve coarctate transition states were investigated by a combination of experimental and theoretical studies. In the thermal fragmentation of ∆-1,3,4-oxadiazolines, the mechanism supported by kinetic isotope effects and theoretical calculations is a three-step process that does not demonstrate any special stabilization in coarctate transition states. Rather than undergoing a direct coarctate conversion to product, the mechanism avoids coarctate steps. The last step is a concerted coarctate reaction, but being concerted may be viewed as being enforced by the necessity to avoid high-energy intermediates. In the deoxygenation of epoxides with dichlorocarbene, the stabilization from the transition state aromaticity is not great enough to compete with the preference for asynchronous bonding changes. KIEs and calculations suggested that the reaction occurs in a concerted manner but with a highly asynchronous early transition state with much more Cα-O bond breaking than Cβ-O bond breaking. In the Shi epoxidation, a large β-olefinic 13C isotope effect and small α-carbon isotope effect indicated an asynchronous transition state with more advanced formation of the C-O bond to the β-olefinic carbon. The calculated lowest-energy transition structures are generally those in which the differential formation of the incipient C-O bonds, the "asynchronicity," resembles that of an unhindered model, and the imposition of greater or less asynchronicity leads to higher barriers. In reactions of cis-disubstituted and terminal alkenes using Shi's oxazolidinone catalyst, the asynchronicity of the epoxidation transition state leads to increased steric interaction with the oxazolidinone when a π-conjugating substituent is distal to the oxazolidinone but decreased steric interaction when the π-conjugating substituent is proximal to the oxazolidinone. Dynamic effects were studied in Diels-Alder reaction between acrolein and methyl vinyl ketone. This reaction yields two products in a ratio of 3.0 ± 0.5. Theoretical studies shows that only one transition structure is involved in the formation of both. Quasiclassical trajectory calculations on an MP2 surface give a prediction of a product ratio of 45:14 (3.2:1), which is in good agreement with the experimental observation.
9

Social and Environmental effects of Bujagali Dam

Muwumuza, Linda January 2014 (has links)
Abstract There has been a steady increment in economic growth in Uganda and as the economy is on the rise, the demand for energy also increases. Hydro power energy production has been growing in Uganda as a result of the different types of dams created in Uganda along the River Nile. Uganda has been trying to reach the target of electricity capacity so as to ensure that her people get the energy required to improve on their livelihoods. Uganda as a whole has different energy sources but in this thesis, Bujagali dam will be at the center of the focus. Looking at the social and environmental impacts made upon its construction in Jinja. The main objective of this thesis was therefore to show how the livelihoods of the people dwelling in the neighborhood and the environment were affected by the construction of the dam. The livelihoods of the people before the construction of the dam were reviewed in regard to their social life as well as the environment from past literature provided. The different aspects in which the people and environment were affected after the construction of the dam were also reviewed through different interviews with the residents of Bujagali.   There were both positive and negative effects, socially, environmentally and economically due to the construction of the Bujagali. The positive social effects were: provision of land for farming, provision of employment opportunities for the residents, increase in tourism at the dam, the falls and the cultural centers, community development including education, health facilities, skill training, water supply and power supply while the negative effects were loss of land, cultural loss, and less access to different points of the river for fishing purposes for the residents. The positive environmental effects were increase in fish species, more health and safety awareness, and thermal plants closure hence less green house gases effects on the ozone layer, the noise levels effects due to the dam construction, were of no consequence as they were in the required standard.  The negative environmental effects were majorly water levels fluctuation that affects the head of water which in turn affects the capacity of power produced at the dam and air quality of the area during and after the construction of the dam especially air emissions. The positive economic effects were: increment of power to the national grid, lower electricity costs, closure of thermal plants as they were expensive to run and maintain and reduction of load shedding. The negative effect was the financial loan that the government of Uganda obtained to construct the dam that has to be paid back.
10

Applying Hand-Drawn Effects Design Principles to the Creation of 3D Effects

Eisinger, Sarah Beth 03 October 2013 (has links)
This thesis centers on the study of the design principles used in creating hand-drawn effects and how they can be applied to computer-generated 3D effects. By studying the rich history of hand-drawn effects animation, artists working on computer-generated films can enhance the emotional impact and visual appeal of their effects without devoting years to creating hand-drawn effects. From reference clips of animated effects and writings by artists, a list of aesthetic guidelines for the production of stylized effects is generated. A series of case study animations is created to demonstrate how these guidelines can be used to create effects in various styles and of various elements.

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