<p>Electricity accounts for much of the primary energy used in China, and more thanthree-quarter of the total electricity is generated by coal combustion. Coal burningcombined with flue gas cleaning system generates large quantity of coal combustionproducts (CCPs), which has caused significant environmental and economic burden tothe economy, ecology and society. Of great importance are thus different applicationswhich contribute to the increased use of CCPs. This thesis looks at an overview ofCCPs production and utilization all around the world and investigates current CCPsapplications as well as potential technically sound and economically justifiedtechnologies. Results of this thesis show that CCPs utilization rate in differentcountries varies widely from 13% to 97%. Worldwide, a significant proportion ofCCPs from the main producers, e.g. China, the United States and India, is still beingdisposed off, resulting in a low-level of overall utilization of these products. It isevident that the amount of CCPs produced substantially exceeds consumptionsbecause of various existing obstacles and limitations. In order to formulate effectiveapproaches, identifying challenges to increased use of CCPs is of great weight. The aimof this thesis is to analyze current and potential utilizations of CCPs and morespecifically address factors that inhibit or promote the use of CCPs from coal-firedpower plants in China.</p><p>Savings of natural resources, energy, emissions of pollutants, GHG emissions anduseful land were found as the major incentives for CCPs utilization. In China, a ban ofsolid clay bricks was also found to be a very powerful measure to stimulate thedevelopment of other by-product based wall materials while saving useful land andprotecting the environment. However, this strong support from the government hasnot been fully implemented, which seriously hampered CCPs uses. Results presentedin this thesis also show that high transportation cost of low unit-value CCPs,competition from available natural materials and spatial variation in supply-demandposes three of the most important barriers to the increased use of CCPs in China.Industrial organizations with assistances from the government have shown to be offundamental importance for formulating approaches to take in overcoming thebarriers.</p><p>This thesis emphasized that transforming laboratory- and pilot-scale technologies intocommercial productivity is of the highest priority for increased use of CCPs. Aconceptual model of CCPs Eco-Industry Park (EIP) as a potential effective solutionwas proposed. Mutual economic and environmental benefits can be achieved throughthe collaboration between different industries in the CCPs EIP. And other feasiblerecommendations of initiatives from both the government and industries were alsodiscussed.</p>

Electricity accounts for much of the primary energy used in China, and more thanthree-quarter of the total electricity is generated by coal combustion. Coal burningcombined with flue gas cleaning system generates large quantity of coal combustionproducts (CCPs), which has caused significant environmental and economic burden tothe economy, ecology and society. Of great importance are thus different applicationswhich contribute to the increased use of CCPs. This thesis looks at an overview ofCCPs production and utilization all around the world and investigates current CCPsapplications as well as potential technically sound and economically justifiedtechnologies. Results of this thesis show that CCPs utilization rate in differentcountries varies widely from 13% to 97%. Worldwide, a significant proportion ofCCPs from the main producers, e.g. China, the United States and India, is still beingdisposed off, resulting in a low-level of overall utilization of these products. It isevident that the amount of CCPs produced substantially exceeds consumptionsbecause of various existing obstacles and limitations. In order to formulate effectiveapproaches, identifying challenges to increased use of CCPs is of great weight. The aimof this thesis is to analyze current and potential utilizations of CCPs and morespecifically address factors that inhibit or promote the use of CCPs from coal-firedpower plants in China. Savings of natural resources, energy, emissions of pollutants, GHG emissions anduseful land were found as the major incentives for CCPs utilization. In China, a ban ofsolid clay bricks was also found to be a very powerful measure to stimulate thedevelopment of other by-product based wall materials while saving useful land andprotecting the environment. However, this strong support from the government hasnot been fully implemented, which seriously hampered CCPs uses. Results presentedin this thesis also show that high transportation cost of low unit-value CCPs,competition from available natural materials and spatial variation in supply-demandposes three of the most important barriers to the increased use of CCPs in China.Industrial organizations with assistances from the government have shown to be offundamental importance for formulating approaches to take in overcoming thebarriers. This thesis emphasized that transforming laboratory- and pilot-scale technologies intocommercial productivity is of the highest priority for increased use of CCPs. Aconceptual model of CCPs Eco-Industry Park (EIP) as a potential effective solutionwas proposed. Mutual economic and environmental benefits can be achieved throughthe collaboration between different industries in the CCPs EIP. And other feasiblerecommendations of initiatives from both the government and industries were alsodiscussed.

A framework for the quantitative analysis of performance, security and database management within a network system (e.g. a cloud computing platform) is presented within this research. Our study provides a methodology for modelling and quantitatively generating significant metrics needed in the evaluation of a network system. To narrow this research, a study is carried-out into the quantitative modelling and analysis of performance, security and database management trade-offs in cloud computing platforms, based on Stochastic Activity Networks (SANs) and combined metrics. Cloud computing is an innovative distributed computing archetypal based on the infrastructure of the internet providing computational power, application, storage and infrastructure services. Security mechanisms such as: batch rekeying, intrusion detection, encryption/decryption or security protocols come at the expense of performance and computing resources consumption. Furthermore, database management processing also has an adverse effect on performance especially in the presence of big data. Stochastic Activity Networks (SANs) that offer synchronisation, timeliness and parallelism are proposed for the modelling and quantitative evaluations of ‘optimal’ trade-offs involving performance, security and database management. Performance modelling and analysis of computer network systems has mostly been considered of utmost importance. Quantification of performance for a while has been assessed using stochastic models with a rising interest in the quantification of security stochastic modelling being applied to security problems. Quantitative techniques that includes analytical valuations founded on queuing theory, discrete-event simulations and correlated approximations have been utilised in the examination of performance. Security suffers from the point that no interpretations can be made in an optimal case. The most consequential security metrics are in analogy with reliability metrics. The express rate at which data grows increases the prominence for research into the design and development of cloud computing models that manages the workload intensity and are suitable for data exploration. Handling big data especially within cloud computing is a resource consuming, time-demanding and challenging task that necessitates titanic computational infrastructures to endorse successful data exploration. We present an improved Security State Transition Diagram (SSTD) by adding a new security state (Failed/Freeze state). The presence of this new security state signifies a security position of the computing network system were the implemented security countermeasures cannot handle the security attacks and the system fails completely. In a more sophisticated security system, when the security countermeasure(s) cannot in any form categorise the security attack, the network system is moved to the Failed/Freeze security state. At this security state, the network system can only resume operation when restored by the system administrator. In this study, we propose a cloud computing system model, defined security countermeasures and evaluated the optimisation problems for the trade-offs between performance, security and database management using SANs formalism. We designed, modelled and implemented dependency within our presented security system, developing interaction within the security countermeasures using our proposed Security Group Communication System (SGCS). The choice of Petri-Nets enables the understanding and capturing of specified metrics at different stages of the proposed cloud computing model. In this thesis, an overview of cloud computing including its classification and services is presented in conjunction with a review of existing works of literature. Subsequently, a methodology is proposed for the quantitative analysis of our proposed cloud computing model of performance-security-database trade-offs using Möbius simulator. Additionally, numerical experiments with relevant interpretations are presented and appropriate interpretations are made. We identified that there are system parameters that can be used to optimise the presented abstract combined metrics but they are optimal for neither performance or security or database management independently. Founded on the proposed quantitative simulation model framework, reliable numerical experiments were observed and indicated scope for further extensions of this work. For example, the use of Machine Learning (ML) or Artificial Intelligence (AI) in the predictive and prevention aspects of the security systems.