• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 13
  • 8
  • 2
  • Tagged with
  • 29
  • 29
  • 11
  • 10
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 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

Dynamic Modelling and Optimisation of Carbon Management Strategies in Gold Processing

sawan.jonguwa@au.experian.com, Pornsawan Jongpaiboonkit January 2003 (has links)
This thesis presents the development and application of a dynamic model of gold adsorption onto activated carbon in gold processing. The primary aim of the model is to investigate different carbon management strategies of the Carbon in Pulp (CIP) process. This model is based on simple film-diffusion mass transfer and the Freundlich isotherm to describe the equilibrium between the gold in solution and gold adsorbed onto carbon. A major limitation in the development of a dynamic model is the availability of accurate plant data that tracks the dynamic behaviour of the plant. This limitation is overcome by using a pilot scale CIP gold processing plant to obtain such data. All operating parameters of this pilot plant can be manipulated and controlled to a greater degree than that of a full scale plant. This enables a greater amount of operating data to be obtained and utilised. Two independent experiments were performed to build the model. A series of equilibrium tests were performed to obtain parameter values for the Freundlich isotherm, and results from an experimental run of the CIP pilot plant were used to obtain other model parameter values. The model was then verified via another independent experiment. The results show that for a given set of operating conditions, the simulated predictions were in good agreement with the CIP pilot plant experimental data. The model was then used to optimise the operations of the pilot plant. The evaluation of the plant optimisation simulations was based on an objective function developed to quantitatively compare different simulated conditions. This objective function was derived from the revenue and costs of the CIP plant. The objective function costings developed for this work were compared with published data and were found to be within the published range. This objective function can be used to evaluate the performance of any CIP plant from a small scale laboratory plant to a full scale gold plant. The model, along with its objective function, was used to investigate different carbon management strategies and to determine the most cost effective approach. A total of 17 different carbon management strategies were investigated. An additional two experimental runs were performed on the CIP pilot plant to verify the simulation model and objective function developed. Finally an application of the simulation model is discussed. The model was used to generate plant data to develop an operational classification model of the CIP process using machine learning algorithms. This application can then be used as part of an online diagnosis tool.
2

The link between carbon management strategy, company characteristics and corporate financial performance

Matthews, Natalie Georgette 23 February 2013 (has links)
That companies need to respond to the issue of climate change is no longer in question and with multiple carbon management activity options to choose from, companies need to select the most appropriate carbon management strategy to meet the challenges of a carbon constrained future. Because of South Africa’s vulnerability to the impacts of climate change as a developing country and because of business’ pivotal role in addressing this urgent issue, it is important to characterise the corporate responses to climate change. The contextual factors that influence carbon management strategy decisions need to be understood so that appropriate policy decisions are taken to encourage innovation related to climate change opportunities.To this end, secondary data in the form of qualitative responses from 70 large South African listed companies to the Carbon Disclosure Project 2011 questionnaire were analysed for this study during September and October 2012. The detailed responses were first mined using a text-mining statistical program to identify the five carbon management activities currently practised by the companies. A cluster analysis of these activities revealed four general response strategies to climate change and carbon emission reduction pressures.The companies were found to have a strong focus on saving energy with less focus on higher-order sustainability activities. While market capitalisation, turnover, sector and carbon commitment were shown to correlate and indeed predict the carbon management strategy chosen by companies, no significant link was found between carbon management strategy and corporate financial performance. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted
3

Carbon management and scenario planning at the landscape scale with GIS in Tamar Valley catchment, England

Delfan Azari, Shabnam January 2012 (has links)
It is now widely believed that globally averaged temperatures will rise significantly over the next 100 years as a result of increasing atmospheric concentrations of greenhouse gases (GHG) such as carbon dioxide. Responses to the threat of future climate change are both adaptations to new climate conditions, and mitigation of the magnitude of change. Mitigation can be achieved both through reducing emissions of greenhouse gases and by increasing storage of carbon in the earth system. In particular it is thought that there is potential for increased storage of carbon on land in soils and growing vegetation. There is now a need for research on the potential impacts of changing land use on terrestrial carbon storage, in particular as rapid land use and land cover change has taken place in most of regions of world over the past few decades due to accelerated industrialization, urbanization and agricultural practice. This thesis has developed a novel methodology for estimating the impacts of land use and land cover change (LULCC) on terrestrial carbon storage using Geographic Information Systems and Optimization modelling, using a regional case study (the Tamar Valley Catchment, southwest England) and drawing entirely on secondary data sources (current distributions of soils and vegetation). A series of scenarios for future land cover change have been developed, for which carbon storage, GHG and energy emissions amount have been calculated over the short, medium and long term (2020, 2050 and 2080). Results show that in this region, improving permanent grassland and expanding forestry land are the best options for increasing carbon storage in soils and biomass. The model has been validated using sensitivity analysis, which demonstrates that although there is uncertainty within the input parameters, the results remain significant when this is modelled within the linear programme. The methodology proposed here has the potential to make an important contribution to assessing the impacts of policies relating to land use at the preparation and formulation stages, and is applicable in any geographic situation where the appropriate secondary data sources are available.
4

Making carbon count : the role of carbon accounting in carbon management and markets

Ascui, Francisco Fernando January 2014 (has links)
Society’s efforts to ‘manage’ the problem of human-induced climate change – for example through setting targets, tracking progress, imposing sanctions and incentives, and creating markets in emission rights and offsets – have given rise to numerous calculation, measurement, attribution, monitoring, reporting and verification challenges, which are being addressed by many different communities (including scientists, governments, businesses and accountants) in many different ways. Carbon accounting – this diverse and ever-expanding assemblage of calculative practices – is a rapidly evolving phenomenon, which has only recently become a subject of academic accountancy-related research. This thesis explores what carbon accounting means, who it involves, and how different communities define and lay claim to competence in the field. It also examines, through case studies on the emergence of the Climate Disclosure Standards Board and the controversies around generating tradable carbon offsets from forestry projects in the UK, the immense technical, cognitive, social and political work required to make carbon measurable, commensurable and thereby amenable to various forms of management. The thesis contributes to both conceptual and practical understanding of carbon accounting as an emerging field of study. Bringing together a wide range of empirical examples of different types of carbon accounting practices, it proposes a unique definition of carbon accounting which expands the horizons of the field. It provides a conceptual basis for making sense of carbon accounting by considering it not as a unitary phenomenon but rather as a set of overlapping frames, each associated with different communities of practice. It shows that competence in carbon accounting is contested, particularly where these frames overlap, and that boundary organisations are emerging that offer the opportunity to negotiate such tensions and lead to more productive policy-making. Finally, it makes the case that engagement with the detail of the ‘nuts and bolts’ of carbon accounting is essential, as these apparently technical details can have major implications for the effectiveness of society’s response to climate change, and it is only by opening them up to rigorous scrutiny that we can make progress, both conceptually and practically.
5

Relações causais em sistemas de produção agrícola e agropecuária / Causal relationships in agricultural and integrated crop-livestock systems

Ferreira, Tiago Lima January 2017 (has links)
O presente trabalho teve por objetivo compreender sistemas de produção agrícola e agropecuária a campo pela avaliação da diversidade, funcionalidade e dinâmica espaço-temporal de espécies, assim como pelo padrão de variação da qualidade do solo e dos fatores que a determinam. Para isso, foi avaliado na “Agropecuária Guajuvira” localizada no município de São Miguel das Missões – RS quatro sistemas conservacionistas de produção. Foram eles: 1- sistema agrícola tradicional, representando a sucessão soja/trigo e soja/aveia preta amplamente praticada na região; 2- Sistema agrícola irrigado, semelhante ao anterior, mas, com recente inserção de milho no verão; 3- Sistema integrado de produção agropecuária 1, representando a sucessão soja/pastejo de azevém e 4- Sistema integrado de produção agropecuária 2, representando um sistema misto por apresentar alterações na composição de espécies no inverno pela sucessão soja/aveia preta pastejada, soja/aveia preta não pastejada e soja/nabo forrageiro/trigo O estoque de carbono (EC), estabilidade de agregados do solo (EAS) e índice de manejo de carbono (IMC) foram escolhidos como indicadores da qualidade sistêmica do solo. Seus padrões de variação foram compreendidos pela integração de atributos químicos, físicos e biológicos do solo, assim como por variáveis de paisagem inerentes às unidades amostrais. Os fatores que caracterizaram os sistemas de produção e o uso da análise de caminhos permitiram um maior entendimento de sistemas complexos de produção agrícola e agropecuária a campo. / The aim of this research was to understand agricultural and integrated crop-livestock production systems by the species diversity, functionality and spatial-temporal dynamics evaluation, as well as of the variation pattern of soil quality and factors that determine then. For this, four no-tillage production systems were evaluated on the "Agropecuária Guajuvira" located in São Miguel das Missões county in southern Brazil. The production systems were: 1- Traditional agricultural system, representing the succession soybean/wheat and soybean/black oat widely practiced in the region; 2- Irrigated agricultural system, similar to the previous one, but, with recent insertion of corn in the summer; 3 - Integrated crop-livestock system 1, representing the succession of soybean /grazed ryegrass and 4 - Integrated crop-livestock system 2, representing a mixed system due changes in species composition during winter by succession of soybean/grazed black oat, soybean/no-grazed black oat and soybean/forage radish/wheat The carbon stock (CS), soil aggregate stability (SAS) and carbon management index (CMI) were chosen as systemic soil quality indicators. Their variation patterns were understood by the integration of chemical, physical and biological soil attributes, as well as by landscape variables inherent to the sampling units. The factors that characterized the production systems and the path analysis utilization allowed a greater understanding of complex agricultural and integrated crop-livestock production systems in the field.
6

Microfluidic Analysis for Carbon Management

Sell, Andrew 28 November 2012 (has links)
This thesis focuses on applying microfluidic techniques to analyze two carbon management methods; underground carbon sequestration and enhanced oil recovery. The small scale nature of microfluidic methods enables direct visualization of relevant pore-scale phenomena, enabling elucidation of parameters such as diffusion coefficients and critical compositions. In this work, a microfluidic platform was developed to control a two-phase carbon dioxide (CO2)-water interface for diffusive quantification with fluorescent techniques. It was found that the diffusion coefficient of CO2 in pure water was constant (1.86 [± 0.26] x10-9 m2/s) over a range of pressures. The effects of salinity on diffusivity were also measured in solutions, it was found that the diffusion coefficient varied up to 3 times. A microfluidic technique able to determine the critical composition of a model ternary mixture was also successfully implemented. Results indicate potential application of this approach to minimum miscibility pressure measurements used in enhanced oil recovery.
7

Organizational Involvement in Carbon Mitigation: The New Zealand Public Sector

Birchall, Stephen Jeffrey January 2013 (has links)
Introduction: New Zealand (NZ) ratified the Kyoto Protocol in 2002, committing to prudent greenhouse gas (GHG) emission reductions. In an effort to promote public sector carbon management, in 2004, Clark’s Labour-led Government funded local government membership in ICLEI’s Communities for Climate Protection - NZ (CCP-NZ) programme. In 2007, the same Government, in tandem with efforts to price carbon and develop an Emissions Trading Scheme, through the Carbon Neutral Public Service (CNPS) programme, sought to move the core public sector towards carbon neutrality (Clark, 2007c). In 2008, the NZ government changed from a Labour-led to a National-led Government, and this resulted in a shift in its carbon emission mitigation strategy, including the termination of the CNPS and the CCP-NZ programmes. Purpose: The research has two central objectives: First, to determine why NZ’s newly elected National -led Government cancelled the CNPS and the CCP-NZ programmes; and, second, to determine whether despite the discontinuation of these two programmes and in the absence of Government support, will NZ government organizations continue to strive for carbon emission reductions and neutrality. Approach: This empirical research is investigative and probing, and comprises a series of semi-structured interviews with senior managers responsible for the delivery of the CNPS and the CCP-NZ programmes within their respective organization. The architects of each programme (e.g. the NZ Prime Minister and CEO of ICLEI/ Director of ICLEI Oceania) are also investigated in order to glean insight into the rationale for the ultimate termination of these two programmes. Fieldwork is informed by publicly available information that provides insight into Government’s rationale for creating and discontinuing the CNPS and the CCP-NZ programmes. Narrative analysis and termination theory serve as the primary methodological tools for this study, providing insight into meaning, interpretation and individual experience as it relates to the dismantling of the CNPS and the CCP-NZ programmes. Findings: This study finds that though economic constraints and programmatic inefficiencies may have played a contributing role, political ideology is the primary rationale for the termination of the CNPS and the CCP-NZ programmes. With the ideological shift towards strong neoliberal market environmentalism, Government support for initiatives like the CNPS and the CCP-NZ programmes has declined markedly, with the desire to demonstrate leadership in this area in complete retreat. Ultimately, notwithstanding the desire of some government organizations to continue with programme objectives, albeit with less priority, NZ public sector organizational resolve towards these goals has weakened.
8

Microfluidic Analysis for Carbon Management

Sell, Andrew 28 November 2012 (has links)
This thesis focuses on applying microfluidic techniques to analyze two carbon management methods; underground carbon sequestration and enhanced oil recovery. The small scale nature of microfluidic methods enables direct visualization of relevant pore-scale phenomena, enabling elucidation of parameters such as diffusion coefficients and critical compositions. In this work, a microfluidic platform was developed to control a two-phase carbon dioxide (CO2)-water interface for diffusive quantification with fluorescent techniques. It was found that the diffusion coefficient of CO2 in pure water was constant (1.86 [± 0.26] x10-9 m2/s) over a range of pressures. The effects of salinity on diffusivity were also measured in solutions, it was found that the diffusion coefficient varied up to 3 times. A microfluidic technique able to determine the critical composition of a model ternary mixture was also successfully implemented. Results indicate potential application of this approach to minimum miscibility pressure measurements used in enhanced oil recovery.
9

Has Carbon Disclosure Become More Transparent in the Global Logistics Industry? An Investigation of Corporate Carbon Disclosure Strategies between 2010 and 2015

Herold, David Martin January 2018 (has links) (PDF)
Global logistics companies are increasingly disclosing carbon related information due to institutional and stakeholder pressures. Existing research, however, is limited to categorizing these pressures and their influences on corporate carbon disclosure strategies. In particular, literature to date has not distinguished between different carbon disclosure strategies and how they may have changed over time. In response, this paper: (1) proposes a framework that depicts four different carbon disclosure responses and strategies based on internal and external pressures; and (2) subsequently analyzes and compares corporate carbon disclosure strategies between 2010 and 2015. Using a sample of 39 leading global logistics companies, carbon disclosure strategies are categorized based on the analysis of 25 applied carbon management practices from Bloomberg ESG to see if carbon management practices and the associated strategies have changed. The findings show overall shifts to more transparent corporate carbon disclosure strategies between 2010 and 2015 with an increase of applied carbon management practices in both internal and external actions.
10

Relações causais em sistemas de produção agrícola e agropecuária / Causal relationships in agricultural and integrated crop-livestock systems

Ferreira, Tiago Lima January 2017 (has links)
O presente trabalho teve por objetivo compreender sistemas de produção agrícola e agropecuária a campo pela avaliação da diversidade, funcionalidade e dinâmica espaço-temporal de espécies, assim como pelo padrão de variação da qualidade do solo e dos fatores que a determinam. Para isso, foi avaliado na “Agropecuária Guajuvira” localizada no município de São Miguel das Missões – RS quatro sistemas conservacionistas de produção. Foram eles: 1- sistema agrícola tradicional, representando a sucessão soja/trigo e soja/aveia preta amplamente praticada na região; 2- Sistema agrícola irrigado, semelhante ao anterior, mas, com recente inserção de milho no verão; 3- Sistema integrado de produção agropecuária 1, representando a sucessão soja/pastejo de azevém e 4- Sistema integrado de produção agropecuária 2, representando um sistema misto por apresentar alterações na composição de espécies no inverno pela sucessão soja/aveia preta pastejada, soja/aveia preta não pastejada e soja/nabo forrageiro/trigo O estoque de carbono (EC), estabilidade de agregados do solo (EAS) e índice de manejo de carbono (IMC) foram escolhidos como indicadores da qualidade sistêmica do solo. Seus padrões de variação foram compreendidos pela integração de atributos químicos, físicos e biológicos do solo, assim como por variáveis de paisagem inerentes às unidades amostrais. Os fatores que caracterizaram os sistemas de produção e o uso da análise de caminhos permitiram um maior entendimento de sistemas complexos de produção agrícola e agropecuária a campo. / The aim of this research was to understand agricultural and integrated crop-livestock production systems by the species diversity, functionality and spatial-temporal dynamics evaluation, as well as of the variation pattern of soil quality and factors that determine then. For this, four no-tillage production systems were evaluated on the "Agropecuária Guajuvira" located in São Miguel das Missões county in southern Brazil. The production systems were: 1- Traditional agricultural system, representing the succession soybean/wheat and soybean/black oat widely practiced in the region; 2- Irrigated agricultural system, similar to the previous one, but, with recent insertion of corn in the summer; 3 - Integrated crop-livestock system 1, representing the succession of soybean /grazed ryegrass and 4 - Integrated crop-livestock system 2, representing a mixed system due changes in species composition during winter by succession of soybean/grazed black oat, soybean/no-grazed black oat and soybean/forage radish/wheat The carbon stock (CS), soil aggregate stability (SAS) and carbon management index (CMI) were chosen as systemic soil quality indicators. Their variation patterns were understood by the integration of chemical, physical and biological soil attributes, as well as by landscape variables inherent to the sampling units. The factors that characterized the production systems and the path analysis utilization allowed a greater understanding of complex agricultural and integrated crop-livestock production systems in the field.

Page generated in 0.0731 seconds