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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.
81

Development Of A Chemical Kinetic Model For A Fluidized-bed Sewage Sludge Gasifier

Champion, Wyatt 01 January 2013 (has links)
As the need for both sustainable energy production and waste minimization increases, the gasification of biomass becomes an increasingly important process. What would otherwise be considered waste can now be used as fuel, and the benefits of volume reduction through gasification are seen in the increased lifespan of landfills. Fluidized-bed gasification is a particularly robust technology, and allows for the conversion of most types of waste biomass. Within a fluidized-bed gasifier, thermal medium (sand) is heated to operating temperature (around 1350°F) and begins to fluidize due to the rapid expansion of air entering the bottom of the reactor. This fluidization allows for excellent heat transfer and contact between gases and solids, and prevents localized "hot spots" within the gasifier, thereby reducing the occurrence of ash agglomeration within the gasifier. Solids enter the middle of the gasifier and are rapidly dried and devolatilized, and the products of this step are subsequently oxidized and then reduced in the remainder of the gasifier. A syngas composed mainly of N2, H2O, CO2, CO, CH4, and H2 exits the top of the gasifier. A computer model was developed to predict the syngas composition and flow rate, as well as ash composition and mass flow rate from a fluidized-bed gasifier. A review of the literature was performed to determine the most appropriate modeling approach. A chemical kinetic model was chosen, and developed in MATLAB using the Newton-Raphson method to solve sets of 18 simultaneous equations. These equations account for mass and energy balances throughout the gasifier. The chemical kinetic rate expressions for these reactions were sourced from the literature, and some values modified to better fit the predicted gas composition to literature data.
82

The Political Economy of Environmental Justice: A Comparative Study of New Delhi and Los Angeles

Asokan, Ratik 01 January 2015 (has links)
Though mainstream environmentalism, both in the U.S. and India, was initially rooted in social justice, it has, over time, moved away from this focus. The Environmental Justice Movement consequently arose to reunite social and environmental activism. In this thesis, I trace the historical relationship between the mainstream environmentalism, the Environmental Justice Movement, and marginalized communities. After providing this general overview, I examine two case studies – in Los Angeles and New Delhi respectively – where marginalized communities have been involved in Environmental Justice activities. My analysis reveals that marginalized communities often act in an ‘environmentalist’ or ‘environmentally friendly’ manner, without defining their actions as such. That is, their socio-political activism often is or becomes environmental because of the contexts it operates within.
83

Efektivní provoz moderních jednotek EVO / Effective operation of up-to-date waste-to-energy units

Cafourková, Tereza January 2009 (has links)
The main content of this thesis is a suggestion of computing system for efficient energy manufacture. The introduction devotes to description of up-to-date waste-to-energy units (EVO), it concentrates on Incinerator of municipal wastes of TERMIZO a.s., specifically. In the main body of this work is the data analysis of factory journal that has been implemented, results have been used as mathematical model output value. These activities are necessary for computing system suggestion. Resulting optimization of batch wasting plan with maximum economic effect for entrepreneur is the main output of this work. Conclusion consists of environmental and economic evaluation of operation of up-to-date waste-to-energy units and offers another optimization posibility.
84

Implementation of waste management policy in the City of Tshwane

Mokebe, Thabo 06 1900 (has links)
The City of Tshwane is the capital city of South Africa and the administrative seat of government. The status of the city as a capital creates high expectations on the level of basic service delivery on municipal services like waste management, water, electricity and health. The city is currently facing challenges in relation to the delivery and implementation of waste management services. In an attempt to find solutions to the waste management challenges of the city a study on the implementation of waste management services is undertaken by the researcher. The study identifies and then analyses the underlying reasons for the challenges faced by the City of Tshwane in the implementation of waste management services. This aim of this study was to investigate and to analyse the implementation of waste management services in the City of Tshwane’s historically disadvantaged areas with particular focus on Region 01, 02, 05 and 07. In order to investigate these factors, a descriptive research design and qualitative methodology was used which related to convenient and purposive sampling of officials and data collected from fifteen (15) respondents using semi structured interviews and observations. The study also utilised document analysis to interpret the challenges and solutions related to the research topic. It emerged from the study that a lack of capacity and resources to perform efficient waste management services underpinned many of the challenges experience by the city. The failure of the city to ensure community participation and involvement is another reason for the challenges the city faces in waste management. Furthermore, the lack of policy implementation and enforcement is an element that the city needs to deeply consider. When policy is crafted with input of residents and when there is a social contract as to the roles and responsibilities of each party, it becomes easier to enforce. Some of the challenges that the city faces with regards to waste management can also be attributed to political interference and institutional deficiencies. Beyond issues like capacity, institutions and others, the city will continue to face challenges if it does not seriously invest in innovation and new technologies that address its generic and specific conditions in relation to the management of waste. The marginalisation and selective enforcement of by-laws on the informal recyclers and reclaimers are some of the findings of the study that demonstrate the inability of the city to find specific solutions to specifics regions on waste management .These challenges resulted in the peri urban regions like region 01, 02, 05 and 07 not receiving quality and consistent waste management services. The study recommends some interventions to address the waste management problems identified in the highlighted regions and entire City of Tshwane. Some of the recommended interventions include, assessing the unique characteristics of the communities and regions with a view of identifying waste management solutions that will be relevant for the circumstances and profile of such regions, ensure that proper and adequate resources, infrastructure and capacity is deployed to such areas to improve the waste services in those areas. Furthermore aggressive education and awareness campaigns conducted in partnership with communities will be critical to change people’s attitude towards waste management and a clean environment. This can be achieved through a consultative process led by the City of Tshwane in partnership with its communities and enforced through a progressive and incentive driven by-law system. / Public Administration and Management / M.P.A. (Master of Public Administration)

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