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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.
1151

Spatial structure of physical properties of a typic torrifluvent

Gajem, Yousif Mohamed January 1980 (has links)
No description available.
1152

Developing infant technologies in mature industries : a case study on renewable energy

Odam, Neil January 2011 (has links)
The purpose of this thesis is to investigate the development of new technologies in the energy industry and to explore how it is possible for these technologies to compete with incumbent technologies in a mature market. The pursuit of renewable energy has been at the forefront of national government and international institutional policy in recent years due to the desire to improve the security of energy supply and to reduce CO2e emissions. This thesis aims to contribute to this policy debate, particularly by focussing on the issue of governmental support for infant energy technologies. In order to conduct this investigation, two main topics have been analysed. Firstly, learning curves have been studied to establish whether support for new technologies can be justified by the potential cost reductions which arise from learning-by-doing. This research evolved into the investigation of econometric issues which affect learning curves. Patent counts are used to demonstrate an alternative output-based measurement of industry wide knowledge stock, which is used as a proxy for innovation. This alternative specification of knowledge stock corroborates recent findings in the literature, that learning curves which model cost using only cumulative capacity leads to the over-estimation of cost reductions from learning-by-doing and the failure to capture cost reductions resulting from innovation. This suggests that government support for infant technologies should form a dual strategy of incentivising the deployment of generators as well as encouraging innovation, instead of using feed-in tariffs or renewable obligations which narrowly focus on increasing deployment. A great deal of progress has been made in identifying further econometric problems affecting learning curves in recent years. In the progress of this study, it was identified that cumulative capacity, the cost of wind power and knowledge stock are all non-stationary time series variables. The hypothesis that these variables are cointegrated was rejected by the Westerlund test, which implies that learning curves produce spurious results. This has major consequences for government policy as it suggests that learning curves should not be used to justify support for infant technologies. Secondly, a choice experiment was conducted to determine Scottish households’ willingness to pay for electricity generated from renewable sources compared to conventional sources such as coal, oil and gas. A labelled choice experiment was used to determine whether households have preferences between onshore wind power, offshore wind power and wave power. The results of a latent class model reveal that the majority of households (76.5%) are willing to pay an additional £89-£196 per year to obtain electricity from renewable resources instead of conventional sources. However, there is no statistically significant difference in the willingness to pay between the renewable technologies included in the choice experiment. The latent class model also illustrated that there is a sizeable minority (23.5%) who are opposed to renewable energy development. Older respondents and those less concerned about CO2 emissions are significantly more likely to form part of this group at the 5% level of significance. The study also included a unique addition by identifying households which purchased a house in the previous seven years. Interacting the actual transaction prices of these houses in a multinomial logit model suggested that households may be concerned about renewable energy developments devaluing their properties or the additional expense required to power larger houses. Due to the increasing difficulty of conducting choice experiments in the UK, a novel method of eliciting choice experiment responses from online advertising was tested and was found to be a cost-effective method of eliciting choice experiment responses. Overall, the research indicates that caution should be exercised when interpreting the results of a choice experiment which elicits responses using Internet advertising. It can be observed that the pseudo R2 of the Internet-based sample is lower than the mail-based sample and that the mean respondent to the Internet-based choice experiment is willing to pay significantly more for renewable electricity than the mean respondent to the mail-based choice experiment at the 5% level of significance. Furthermore, the mean willingness to pay estimate in the Internet-based choice experiment appears to be unrealistically high. Further research investigating the elasticity of survey responses to the prize fund on offer would be valuable in identifying the most cost-effective strategy to obtain responses and to generate a more representative sample.
1153

The effects of steer manure loading rate and cropping pattern upon soil fertility status

Hathorn, Scott, 1951- January 1978 (has links)
No description available.
1154

Effects of rising air and soil temperatures on the life cycle of important pathogens in oilseed rape (Brassica napus L.) in Lower Saxony

Siebold, Magdalena 15 November 2012 (has links)
No description available.
1155

Studies on the performance structure and relevant parameters determining individual performance in the Paralympic port Alpine Skiing - Case Study

Campos Vinagre, Nelson Alexandre 29 May 2013 (has links)
No description available.
1156

Competition mechanisms of native and exotic tree species

Kawaletz, Heike 02 August 2013 (has links)
Der Anteil an nicht-einheimischen Pflanzenarten (Neophyten), die durch menschlichen Einfluss in neue Gebiete eingebracht worden sind, hat in den letzten zwei Jahrhunderten deutlich zugenommen. Weltweit gefährdet die Invasion von Neophyten beträchtlich die einheimische Biodiversität und Ökosystemfunktionen. Verschiedene biologische Eigenschaften (z.B. hohe Zuwachsrate und schnelle Vermehrung) führen zu einer besseren Konkurrenzfähigkeit von invasiven Arten und verursachen Veränderungen in der natürlichen Artzusammensetzung. Eine genauere Erfassung der Eigenschaften, die Neophyten zu starken Konkurrenten machen, könnte dabei helfen pflanzliche Invasionen besser zu verstehen und zukünftig effektiver zu steuern. Topfversuche ermöglichen die Untersuchung von Pflanzeninteraktionen unter kontrollierten Bedingungen ohne den schwer kalkulierbaren Einfluss heterogener Umweltfaktoren. Allerdings führen die Langlebigkeit und die größeren Dimensionen von Baumindividuen zu mehr Problemen in Topfversuchen im Vergleich zur Untersuchung krautiger Pflanzen. Aus diesem Grund wurde im Rahmen eines Reviews Literatur ausgewertet, um einen Überblick über die praktische Durchführung von Topfversuchen, die sich ausschließlich mit Baumarten beschäftigen, zu geben. Es ist offensichtlich, dass der Vorteil von Topfversuchen zugleich auch einen Nachteil darstellt: Aufgrund der kontrollierten Bedingungen sind Topfversuche in ihrer Eignung natürliche Gegebenheiten zu imitieren immer eingeschränkt. Die Zuverlässigkeit von Topfversuchen bei der Vorhersage des Baumwachstums unter natürlichen Bedingungen ist daher problematisch. Eine Möglichkeit um die Übertragbarkeit von Topfversuchen zu verbessern, könnte die Durchführung zusätzlicher Felduntersuchungen sein. In einem Topfversuch wurden die, durch Unterschiede in der Wuchsrate, Biomasseproduktion und Biomasseverteilung bedingten, Konkurrenzmechanismen von zwei einheimischen (Quercus robur L., Carpinus betulus L.) und zwei nicht-einheimischen Baumarten untersucht (Prunus serotina Ehrh., Robinia pseudoacacia L.). Einjährige Jungpflanzen wurden verschiedenen intra- und interspezifischen Konkurrenzbedingungen ausgesetzt, mit oder ohne den Einfluss von Wurzelkonkurrenz. Um die Konkurrenzmechanismen genauer zu bestimmen, wurde zwischen Wurzel- und Sprosskonkurrenz unterschieden, indem entweder ober- oder unterirdische Plastiktrennwände in die Töpfe integriert wurden. Es wurde angenommen, dass die Gesamtbiomasseproduktion der Neophyten im Vergleich zur Biomasseproduktion der einheimischen Baumarten signifikant höher ist und dies zu einer Verringerung der Biomasse von Q. robur und C. betulus führt. Des Weiteren wurde der Einfluss der unterirdischen Konkurrenz auf das Wachstum und die Biomasseverteilung der einheimischen Arten gemäß der ‚balanced-growth hypothesis‘ untersucht. Unsere Ergebnisse bestätigen die Annahmen, dass die Biomasseproduktion der beiden Neophyten P. serotina und R. pseudoacacia signifikant höher ist und dies zu einem großen Konkurrenzvorteil und zu einer Biomassereduktion der beigemischten konkurrenzschwächeren einheimischen Arten führt. Der Konkurrenzdruck auf Q. robur und C. betulus wurde vor allem durch die Wurzelkonkurrenz der nicht-einheimischen Arten verursacht. Die Ausschaltung von unterirdischen Pflanzeninteraktionen durch Trennwände führte somit zu einem Anstieg der Biomasseproduktion der beiden einheimischen Arten. Demzufolge scheint sogar ein begrenztes Wurzelvolumen bessere Wachstumsbedingungen zu bieten als direkter Wurzelkontakt mit invasiven Konkurrenten. In Übereinstimmung mit der ‚balanced-growth hypothesis‘ reagieren Q. robur und C. betulus auf die starke unterirdische Konkurrenz durch die Neophyten, indem sie mehr Biomasse in Richtung der Wurzeln transportieren. Die verstärkte Investition der Pflanzen in die Wurzeln geht vor allem zu Lasten von Blatt- und Astbiomasse. Außerdem hat sich gezeigt, dass Artenmischungen aus einheimischen und nicht-einheimischen Bäumen mehr Biomasse produzieren, als man anhand des Wachstums dieser Arten in Monokulturen erwartet hätte. Im Vergleich zu Monokulturen oder Mischungen beider Neophyten war der Konkurrenzdruck für P. serotina und R. pseudoacacia in Mischungen mit den weniger produktiven einheimischen Baumarten geringer. Bei Betrachtung der beiden nicht-einheimischen Arten wird deutlich, dass P. serotina signifikant mehr Biomasse produziert. Trotzdem hat R. pseudoacacia aufgrund der starken Wurzelkonkurrenz einen negativen Einfluss auf die Biomasseproduktion von P. serotina. Wachsen die beiden konkurrenzstarken Neophyten zusammen in einem Topf, produzieren sie weniger Biomasse als in den entsprechenden Monokulturen. Es gibt Anzeichen dafür, dass die starke Konkurrenzfähigkeit der invasiven Neophyten oftmals zu Lasten ihrer Stresstoleranz geht. Damit einhergehend zeigten die beiden nicht-einheimischen Arten im Topfversuch eine höhere Mortalitätsrate: Vor allem P. serotina scheint zudem empfindlich gegenüber Schatten, Trockenheit und Überflutung zu sein. Möglicherweise könnte diese Schwachstelle der Neophyten genutzt werden, um eine weitere Ausbreitung einzudämmen.
1157

LOW RADON PERMEABLE GLOVES AND LASERBALL SIMULATIONS FOR SNO+

Carranza-Barnard, Zachariah 19 March 2014 (has links)
The SNO+ experiment is a multipurpose liquid scintillator detector whose rst goal is to measure neutrinoless double beta decay. This thesis describes two important components: simulations to optimize the time window for the prompt peak of an optical calibration source, the \laserball" and the search for gloves to handle calibration sources while maintaining stringent background conditions. Non-direct light found in laserball runs creates challenges for optical calibration. By changing the time pro le from the standard 4ns to an asymmetric pro le of +2 4 ns this contribution of non-direct light can be reduced up to 45%. Gloves provide an access point to manipulate calibration sources during deployment inside the detector and as barrier to 222Rn, a known background to the experiment. However, typical glove materials are found to permeate large amounts radon. Through a careful selection process the material Silver Shield was chosen for use in SNO+ with a permeation rate of 1:1 10 6 radon atoms/hour.
1158

Ett undervisningsförsök att skapa meningsfullt lärande i frisörens grundläggande tekniker / Meaningful learning of basic hairdressing techniques: Testing a method

Erlandsson, Helena January 2014 (has links)
This Independent work is about testing a method to create meaningful learning and a deeper comprehension in matter of basic hairdressing techniques. I got the idea for this method by reading literature related to my education to become a teacher for hairdressers, the new schoolreform and from my own experience of a teaching method that I saw an opportunity to develope. My teaching method was based on first teaching the pupils the basic techniques, and then give them an assignment were they were to find out their own final result by using a picture for inspiration. They were given an assignment description with certain frames but with freedom of choice how to get to their own final result. By making a job description and a headdrawing to show how the work should be done, and during the process try different ways to achieve the best result, my idea was that a deeper understanding and a feeling of meaningfulness would appear. The result shows that the pupils by freedom within frames experienced meaningful learning and thereby deeper understanding when it comes to basic hairdressing techniques. They also developed skills to write, evaluate their own work and to try new paths for further learning. The conclusion is that this teaching method can be used to achieve the goals according to the be changed and added on to develop the method further, but it is a good foundation as a starting point. / Utvecklingsarbetet i form av ett undervisningsförsök handlade om att försöka skapa meningsfulla lärsituationer och ge djupare förståelse för frisörens grundläggande tekniker. Idén till undervisningsförsöket fick jag genom den valda litteraturen från lärarutbildningen, styrdokumenten samt egna erfarenheten av ett undervisningssätt som jag såg möjligheter att utveckla. Undervisningsförsöket gick ut på att ge eleverna grundteknikerna och utifrån dem ge dem i uppgift att själva hitta ett mål, med en inspirationsbild till hjälp. De fick en uppgiftsbeskrivning, men med frihet att själv hitta vägar att nå sitt mål. Genom att göra en arbetsbeskrivning och en huvudskiss på hur arbetet skulle gå till väga, och under processen prova sig fram till det bästa sättet att nå sitt mål, var tanken att djupare förståelse och en känsla av meningsfullhet skulle uppnås. Resultatet visar att eleverna upplevde att genom frihet inom ramar gav ett meningsfullt lärande och därmed större förståelse för frisörens grundläggande tekniker. De utvecklade även förmågan att skriva, utvärdera sitt eget arbete och pröva nya vägar för fortsatt lärande. Slutsatsen är att detta undervisningssätt kan användas för att uppnå målen i styrdokumenten för Hantverk och Hantverk-Frisör 1 (GY 11 Skolverket). Det finns saker som kan ändras och läggas till för att utveckla undervisningsförsöket ytterligare, men är en god grund att utgå ifrån.
1159

Prediction of Hydrate Plugs in Gas Wells in Permafrost

Bondarev, Edward, Argunova, Kira, Rozhin, Igor 07 1900 (has links)
An approach to predictions of position and size of hydrate plugs inside gas wells has been proposed. It is based on the mathematical model of steady non-isothermal flow of real gas in tubes and an algorithm of calculation of equilibrium conditions of hydrate formation. The proposed approach includes the following steps. 1) Numerically solve the system of ordinary differential equations to find the distributions of pressure and temperature along a particular well. 2) Represent the results of calculations as connection between pressure and temperature. 3) Find the intersection of this function with the calculated or experimental equilibrium curve for a particular natural gas. 4) Find the depth of well from the results of numerical solution.
1160

The UBC south campus farm : the elaboration of an alternative

Masselink, Derek James 05 1900 (has links)
This thesis examines the possibility of retaining, redesigning, and integrating existing farm and forestlands within the proposed South Campus community development at the University of British Columbia (UBC). The central tenant of my thesis is, given the importance of agriculture in the development of human culture and the UBC Point Grey Campus, and the vital role it will play in the 21st Century, agricultural lands and facilities should be conserved and given a place of importance within the UBC landscape. An explanation is provided on how such an integrative proposal for these lands, collectively known as the UBC South Campus Farm, would support the economic, ecological, and social interests and expectations of the University, and the Greater Vancouver Regional District (GVRD), while providing an exciting learning and living environment for students, faculty staff and community members. An alternative proposal for the South Campus Farm and the South Campus community is provided that supports the stated interests of the University and the GVRD. This is accomplished through a careful assessment of the cultural and biophysical features of the South Campus lands and the subsequent development and application of a regenerative design process applied within a fourfold framework based on the concepts of ecology, economy, integrity and beauty. The final design proposal is compared and evaluated against the current situation and the University development plans.

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