• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 436
  • 142
  • 37
  • 34
  • 34
  • 28
  • 7
  • 6
  • 6
  • 5
  • 5
  • 5
  • 4
  • 3
  • 3
  • Tagged with
  • 883
  • 692
  • 264
  • 197
  • 160
  • 138
  • 124
  • 88
  • 88
  • 88
  • 86
  • 74
  • 69
  • 63
  • 62
  • 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.
301

An energy efficient mass transportation model for Gauteng / Kadri Middlekoop Nassiep

Nassiep, Kadri Middlekoop January 2011 (has links)
The demand for forensic social work as a specialist field is increasing rapidly, due to the increasing moral decline of the community and consequent higher demands set to generic social workers. Amendments to existing acts as well as the development of new legislation, lead to more opportunity for the prosecution of the perpetrator, and therefore a higher utilization of the forensic social worker. A need was experienced to do research regarding the gaps experienced by social workers or any other workers who are currently executing forensic assessments with the sexually traumatised child. The aim of the investigation was to determine which gaps social workers experience in the field when assessing a child forensically. A recording procedure was used to obtain qualitative as well as quantitative data. A purposive sampling was used were interviews were held with five participants to obtain the data. A selfdeveloped questionnaire was used as measuring instrument. It is clear from the findings that there are definite gaps within the field of forensic social work and the need of further research within the field of forensic social work in South Africa is highlighted. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.
302

Using lignin biomarkers and 14C, of both river DOC and POC, and permafrost soils, to characterize the impacts of climate warming and permafrost degradation on the organic carbon budget of the Hudson Bay, Canada

Godin, Pamela 08 January 2015 (has links)
This study looks at characterizing the terrigenous OC sources, like permafrost, of POC and DOC through 17 rivers and six soils of the Hudson Bay (HB) using lignin biomarkers, and Δ14C. Our findings show the dominance of the OC flux (89%) from the southwest Hudson Bay Rivers, especially from DOC (93%), shedding light on the sources and fate of OC in HB sediments. With warming, organic cryosols, with high OC content in the Cz horizon, have the potential to release as much as 1.5 gOC/m2 for every cm increase in active layer depth. The [Ad/Al] ratios, when combined with 14C ages of DOM, show that older SOC is being released in some rivers and is fresher than expected due to its preservation within permafrost. S/V and C/V ratios, are well correlated to latitude in DOM, reflecting the vegetation in their drainage basins and can be used to indicate OC sources.
303

Climate change detection over different land surface vegetation classes

Dang, Hongyan 29 September 2009 (has links)
Biosystem variations may occur as a consequence of climate change. Analysis of both modern and paleo-proxy climate data indicates several places on Earth that show biosytem variations possibly resulting from changes in climate. In this thesis, a global land cover classification data set is used to partition the globe into seven re¬gions to study surface temperature changes over different vegetation/surface classes. Statistically significant warming is found from the year 1900 over all regions (except for the ice sheets over Greenland and Antarctica). Outputs from three coupled cli¬mate models (CGCM2, HadCM2 and Parallel Climate Model) are then adopted to examine the detection and attribution of surface temperature trends over the vari¬ous vegetation classes for the past half century. An anthropogenic warming trend is detected in six of the seven regions, which means that anthropogenic activities may have caused detectable influences in the regional surface temperature changes of the past half century. Observed trends are consistent with those simulated in response to greenhouse gas and sulphate aerosol forcing except over tropical forest and water where the models overestimate the warming. The similarity between the resultant scaling factors for each region from the different models underscores the reliability of our detection results.
304

Phytoremediation of Nitrous Oxide: Expression of Nitrous Oxide Reductase from Pseudomonas Stutzeri in Transgenic Plants and Activity thereof

Wan, Shen 01 February 2012 (has links)
As the third most important greenhouse gas, nitrous oxide (N2O) is a stable greenhouse gas and also plays a significant role in stratospheric ozone destruction. The primary anthropogenic source of N2O stems from the use of nitrogen in agriculture, with soils being the major contributors. Currently, the annual N2O emissions from this “soil–microbe-plant” system is more than 2.6 Tg (one Tg equals a million metric tons) of N2O-N globally. My doctoral studies aimed to explore innovative strategies for N2O mitigation, in the context of environmental microbiology’s potential contribution to alleviating global warming. The bacterial enzyme nitrous oxide reductase (N2OR), naturally found in some soils, is the only known enzyme capable of catalyzing the final step of the denitrification pathway, conversion of N2O to N2. Therefore, to “scrub” or reduce N2O emissions, bacterial N2OR was heterologously expressed inside the leaves and roots of transgenic plants. Others had previously shown that the functional assembly of the catalytic centres (CuZ) of N2OR is lacking when only nosZ is expressed in other bacterial hosts. There, coexpression of nosZ with nosD, nosF and nosY was found to be necessary for production of the catalytically active holoenzyme. I have generated transgenic tobacco plants expressing the nosZ gene, as well as tobacco plants in which the other four nos genes were coexpressed. More than 100 transgenic tobacco lines, expressing nosZ and nosFLZDY under the control of rolD promoter and d35S promoter, have been analyzed by PCR, RT-PCR and Western blot. The activity of N2OR expressed in transgenic plants, analyzed with the methyl viologen-linked enzyme assay, showed detectable N2O reducing activity. The N2O-reducing patterns observed were similar to that of the positive control purified bacterial N2OR. The data indicated that expressing bacterial N2OR heterologously in plants, without the expression of the accessory Nos proteins, could convert N2O into inert N2. This suggests that atmospheric phytoremediation of N2O by plants harbouring N2OR could be invaluable in efforts to reduce emissions from crop production fields.
305

Sensitivity of permafrost terrain in a high Arctic polar desert : an evaluation of response to disturbance near Eureka, Ellesmere Island, Nunavut

Couture, Nicole J. January 2000 (has links)
A first approximation of ground ice volume for the area surrounding Eureka, Nunavut, indicates that it comprises 30.8% of the upper 5.9 m of permafrost. Volume depends on the type of ice examined, ranging from 1.8 to 69.0% in different regions of the study area. Excess ice makes up 17.7% of the total volume of frozen materials in the study area. Melt of ground ice in the past has produced thermokarst features which include ground subsidence of up to 3.2 m, formation of tundra ponds, degradation of ice wedges, thaw slumps greater than 50 m across, gullying, and numerous active layer detachment slides. With a doubling of atmospheric carbon dioxide, the rise in mean annual temperatures for the area is projected to be 4.9 to 6.6°C, which would lengthen the thaw season and increase thaw depths by up to 70 cm. The expected geomorphic changes to the landscape are discussed.
306

The implication of global warming on the energy performance and indoor thermal environment of air-conditioned office buildings in Australia

Guan, Li-Shan January 2006 (has links)
Global warming induced by the emissions of greenhouse gases is one of the most important global environmental issues facing the world today. Using the building simulation techniques, this research investigates the interaction and relationship between global warming and built environment, particularly for the air-conditioned office buildings. The adaptation potential of various building designs is also evaluated. Based on the descriptive statistics method, the Pearson Product Moment Correlation and the regression analysis method, ten years of historical hourly climatic data for Australia are first analyzed. The distribution patterns of key weather parameters between a Test Reference Year (TRY) and multiple years (MYs), and between relatively cold and hot years are also compared. The possible cross-correlation between several different weather variables are then assessed and established. These findings form a useful basis and provide insights for the development of future weather models under "hot" global warming conditions and the explanation of building performance at different locations. Based on a review of the existing weather data generation models and findings from historic climatic data analysis, an effective method to generate approximate future hourly weather data suitable for the study of the impact of global warming is presented. This is achieved by imposing the future temperature projection from the global climate model on top of the historically observed weather data. Depending on the level of information available for the prediction of future weather conditions, this method allows either the method of retaining to current level, constant offset method or diurnal modelling method to be used. Therefore it represents a more comprehensive and holistic approach than previous one that have been used to convert the available weather data and climatic information to a format suitable for building simulation study. An example of the application of this method to the different global warming scenarios in Australia is also presented. The performance of a representative office building is then examined in details under the five weather scenarios (present, 2030 Low, 2030 High, 2070 Low and 2070 High) and over all eight capital cities in Australia. The sample building used for this study is an air conditioned, square shape, ten storey office tower with a basement carpark, which is recommended by the Australian Building Codes Board to represent the typical office building found in the central business district (CBD) of the capital cities or major regional centres in Australia. Through building computer simulations, the increased cooling loads imposed by potential global warming is quantified. The probable indoor temperature increases and overheating problems due to heat load exceeding the capacity of installed air-conditioning systems are also presented. It is shown that in terms of the whole building indoor thermal environment, existing buildings would generally be able to adapt to the increasing warming of the 2030 year Low and High scenarios projections and the 2070 year Low scenario projection. For the 2070 year High scenario, the study indicates that the existing office buildings in all capital cities will suffer from the overheating problem. To improve the building thermal comfort to an acceptable standard (ie, less than 5% of occupied hours having indoor temperature over 25°), a further increase of 4-10% of building cooling load is required. The sensitivity of different office building zoning (i.e. zone at different floors and/or with different window orientation) to the potential global warming is also investigated. It is shown that for most cities, the ground floor, and the South or Core zone would be most sensitive to the external temperature change and has the highest tendency to having the overheating problem. By linking building energy use to CO2 emissions, the possible increase of CO2 emissions due to increased building energy use is also estimated. The adaptation potential of different designs of building physical properties to global warming is then examined and compared. The parametric factors studied include the building insulation levels, window to wall ratio, window glass types, and internal load density. It is found that overall, an office building with a lower insulation level, smaller window to wall ratio and/or a glass type with lower shading coefficient, and lower internal load density will have the effect of lowering building cooling load and total energy use, and therefore have a better potential to adapt to the warming external climate. This phenomenon can be linked to the nature of internal-load dominated office-building characteristics. Based on these findings, a series of design and adaptation strategies have been proposed and evaluated.
307

Ship of Fools

Collins, Julie January 2008 (has links)
The Ship of Fools is an ancient allegory that has long been a part of Western culture in literature, art and song... It has been chosen by many to comment on contemporary issues throughout history, highlighting the foibles of that society. The ship of fools however is also about our world, as a vessel, full of passengers of humanity, full of those who have no care what they do or where they are going... It is the 21st Century and we are all sailing on a Ship of Fools. We consume beyond reason, we want, and get the latest, newest, biggest things. We complain about interest rates and petrol prices, but consume beyond reason often with purchases on credit we don't really need. / Master of Arts (Visual Arts)
308

Effect of temperature on the accumulation and repair of UV damage in Symbiodinium and corals

Ms Ruth Reef Unknown Date (has links)
No description available.
309

Organizational Adaptation and Resilience to Extreme Weather Events

Martina Linnenluecke Unknown Date (has links)
Impacts from climate change already pose major challenges for organizations and industrial systems, and vulnerabilities are expected to increase in the future, particularly in vulnerable sectors and locations. Findings by the Intergovernmental Panel on Climate Change (IPCC) suggest that climate change related vulnerabilities of organizations and industries, but also of settlement and society as a whole, are mainly related to changes in the intensity and/or frequency of extreme weather, rather than to gradual climate change impacts. Organization researchers and managers, however, have not yet systematically considered the organizational implications of changes in trends of weather extremes, such as changes to the intensity and/or frequency of storms, floods, and droughts. While companies in the reinsurance industry (e.g., Munich Re, Swiss Re) have begun to undertake research into changes in trends of extremes, most current debates on climate change and corporate response are mainly focused on adaptation – that is, longer-term adjustments that organizations can take in response to policy and legislative changes and the observed gradual warming trend. The question of how organizations can cope with more frequent and/or intense weather extremes has largely remained outside of these debates. The thesis advances the notion that the resilience concept which originated in disciplines such as ecology and engineering may provide insights into dealing with new types of environmental change arising from changes in patterns of weather extremes. It emphasizes that organizational adaptation and resilience potentials are context-specific and related to the characteristics of particular climate change impacts. While organizations may be able to undergo steady adaptations to gradual climate change (such as gradual increases in mean temperatures), they might not be able to handle disruptions that go beyond this gradual trend and are related to changes in extremes. Included in this thesis are five papers that seek to provide a foundation for understanding, assessing and evaluating organizational responses to more frequent and/or intense weather extremes. The first paper serves as an introduction to the thesis, assesses the literatures on organizational adaptation and resilience, and proposes an initial model that draws together the different streams of literature on climate change, adaptation and resilience. The second paper extends on the themes of the first paper and provides a discussion of the concepts of adaptation and resilience, as well as their applicability to different types of climate change impacts. The third paper serves as a method paper and discusses assessment methods and pathway to study organizational resilience. The key difficulties identified in this paper are the uncertainties about future climate change outcomes across temporal and spatial scales and a lack of insight into what leads to organizational resilience, or which variables should be measured in a given study. The fourth paper is an empirical study about the 2009 Victorian Bushfires. While individual extreme events cannot be directly linked to climate change impacts, this study highlights that part of the problem in drawing out the resilience of organizations to an unprecedented and ‘more-severe-than-expected’ extreme event is that a range of contingent variables across organizational and societal and ecological levels are potentially relevant. The last paper discusses the potential inability of organization to adjust to changes in climate and weather, and implications in terms of a necessity of a geographical shift of organizational and industrial activities. The thesis highlights gaps in our understanding of organizational challenges and suggests avenues for future research.
310

Putting the spin on wind energy: risk management issues associated with wind energy project development in Australia

Finlay-Jones, Richard Unknown Date (has links)
The debate on global warming is over (Stix, 2006 p24). The global community must now find ways to reduce greenhouse emissions, particularly from energy generation. Wind energy provides one of the potential solutions to generate renewable energy without creating harmful greenhouse gases. Wind energy is the fastest growing energy generation industry globally (‘Operating wind power capacity' 2006a). This rapid growth is being driven by increasing global energy demand, commitment from governments globally to international agreements including the Kyoto Protocol (UNFCCC 1997) to reduce the emission of greenhouse gases, as well as individual country commitments to mandatory renewable energy targets. Australia, whilst being a signatory to the United Nations Framework Convention on Climate Change (UNFCCC) commitment to reduce greenhouse gas emissions, has so far failed to ratify the Kyoto Protocol. In Australia, wind energy development to date has been driven primarily by the development of the Mandatory Renewable Energy Target (MRET) under the Renewable Energy (Electricity) Act 2000. This requires a commitment to 2% of total electricity generation (9,500GW) to be derived from renewable energy sources by the year 2010 (Warwryk, undated). It is now understood, that the current federal obligation to renewable energy is now oversubscribed, and consequently the likelihood of further wind energy projects being developed is highly limited (Brazzale 2005). External to the government commitment to renewable energy, the development of wind energy projects requires a range of inputs including, but not limited to; an understanding of the wind resource, security of land, access to suitable electricity transmission grid, a market for the electricity, access to suitable technology and a level of community support. Whilst the literature related to project management and risk management is extensive, the literature related to the risks associated with wind energy development in Australia is limited. This research then seeks to fill a void that asks the question; How can project managers minimise the risk associated with wind energy developments in Australia? To investigate this research problem, comparative case study analysis was adopted as a methodology utilising a structured interview process of project managers responsible for the development of 8 Australian wind energy projects. This research shows that the greatest risk to Australian projects is the lack of security associated with the current federal legislation and the consequent loss of market value of the power from wind energy projects. A number of additional primary and secondary risks are identified by the interview participants, and the research is able to draw out three common themes of risk management strategies. These three themes were categorised as conservatism, due diligence and proactivism. This study contributes to the research associated with project management, risk management and wind energy development. This insight into the Australian wind energy industry provides policy makers, educators and stakeholders with information to assist in improving the political, economic and social environment for further wind energy development, in order to mitigate against further greenhouse gas emission and combat global warming.

Page generated in 0.0589 seconds