Toward a new church in a new Africa : a biographical study of Bishop Ralph Edward Dodge 1907-2008

https://place.asburyseminary.edu/ecommonsatsdissertations/2152/thumbnail.jp

Risk-based interruption cost index based on customer and interruption parameters

Includes bibliographical references.Modern competitive electricity markets do not ask for power systems with the highest possible technical perfection, but for systems with the highest possible economic efficiency. Higher economic efficiency can only be achieved when accurate and flexible analysis tools are used. Thus, the modelling of reliability inputs, methodology applied in assessing supply reliability and the interpretation of the reliability outputs should be carefully considered in power system management. In order to relate investment costs to the resulting levels of supply reliability, it is required that supply reliability be quantified in a monetary way. This can be done by calculating the expected interruption costs. Interruption costs evaluation, however, cannot be done correctly in all cases by methods that are based on the commonly used average values. It is the objective of this thesis to find a new way of calculating interruption costs which would combine the precision of a probabilistic method with the flexibility and correctness of customer and interruption parameters. A new reliability worth index was found, based on customer and interruption parameters. This new index was called a Risk-based interruption cost (RBIC) index and is described in detail in this thesis. The technique applies a time-based probabilistic modelling approach to network reliability worth parameters. The approach uses probability distribution functions to model customer interruption costs (CICs) while taking into account seasonal, day-of-week and time-of-day infl uences. In addition, customer specific parameters - economic activity, energy consumption, turnover and power interruption mitigation measures are used to segment electricity customers into customer cluster segments of similar cost profiles. Unlike the conventional deterministic approach, the new technique thus considers variability in CICs. The new model and methods to calculate the new reliability worth index have been implemented in a computer program and the accuracy of the calculation method was tested in various case studies and by comparison with the traditional average process. This research shows that probability density functions are superior to deterministic average values when modelling reliability worth parameters. Probability distribution functions reflect the variability in reliability worth parameters through their dispersion and skewness. Disregarding the effects of probability distribution of the interruption cost leads to large errors, up to 40% and more, in the calculated expected interruption costs. The actual error in specific reliability worth calculations is hard to estimate. It is however clear that this error cannot be simply ignored. Furthermore, the risk-based approach applied to the interpretation of risk-based interruption cost (RBIC) index significantly influences the perception on the network's reliability performance. The risk-based approach allows the uncertainty allowed in a network planning or iv operation decision to be quantified. Use of the new reliability worth index offer more flexibility in reliability worth assessment and produce more accurate results. It can be used in all areas of power system reliability worth assessment which have always been exclusive domain of the average process

Reliability cost and worth assessment of industrial and commercial electricity consumers in Cape Town

Includes bibliographical references (leaves 104-107).A good understanding of the financial value that electricity customers place on power supply reliability and the underlying factors that give rise to higher and lower values is an essential tool in the designing, planning and operating standards of power system networks. This research study is a first step toward addressing the current absence of consistent data needed to support better estimates of the economic value of power supply reliability. The economic value of power supply reliability is usually measured through power interruption costs faced by electricity customers. The aim of this research study was to develop Customer Interruption Cost (CIC) models for both commercial and industrial customers

The multiple faces of cardiovascular disease:From lipoprotein a to epigenetics

Although major strives have been made in the cardiovascular field, there are still multiple roadblocks on the way, which are expected to become more prevalent due to the growing aging population. This thesis adopts a “bedside to bench and back” approach to shed light on three of these roadblocks and provides mechanistic insights in these underlying cardiovascular processes. In part I, we studied the atherogenicity of Lp(a), thereby providing mechanistic insight in how Lp(a) is a major driver for cardiovascular disease. Then, in part II, we described a novel 3D in vitro model, which could be used to validate molecule drug targets and thereby potentially exclude ineffective drug targets at an earlier stage in the drug development pipeline. Lastly, part III focused on an alternative approach for targeting residual inflammatory risk in atherosclerosis, specifically by targeting the epigenetic machinery that regulates the expression of pro-inflammatory genes

Optimal operation of smart multi-energy hub systems incorporating energy hub coordination and demand response strategy

Abstract: This paper considers the operation and optimization of a smart multi-energy hub system network using the energy hub concept. The case study system network includes integrated solar photovoltaic, thermal power generation units and natural gas CHP unit systems. A demand response - dynamic economic emission optimisation model is applied in the case study and allows for a comparison of energy hub control strategies, including the evaluation of economic, environmental criteria and power import between energy hubs. Results show a significant reduction of more than 50% in both total generation cost and amount of emission when different energy hub control strategies are employed. The results also show that load shifting capabilities of different energy hub loads cannot be ignored as it reduces the electricity bill of energy hub customers

Optimal reactive power dispatch of power system networks with distributed generation using particle swarm optimisation

Abstract: This paper presents a particle swarm optimisation (PSO) based approach for solving optimal reactive power dispatch in order to minimise transmission power losses of a system network with distributed generation. The control variables of the system network are bus voltage magnitudes, transformer tap settings and reactive power generation capability of the distributed generation unit. The PSO algorithm is tested on a standard IEEE 14 bus system network and is validated using Newton Raphson method. Results show that the PSO algorithm performs better than the Newton Raphson method. The results also show that distributed generation unit sizing and placement has a great effect on the transmission power losses of the system network

The multiple faces of cardiovascular disease:From lipoprotein a to epigenetics

Although major strives have been made in the cardiovascular field, there are still multiple roadblocks on the way, which are expected to become more prevalent due to the growing aging population. This thesis adopts a “bedside to bench and back” approach to shed light on three of these roadblocks and provides mechanistic insights in these underlying cardiovascular processes. In part I, we studied the atherogenicity of Lp(a), thereby providing mechanistic insight in how Lp(a) is a major driver for cardiovascular disease. Then, in part II, we described a novel 3D in vitro model, which could be used to validate molecule drug targets and thereby potentially exclude ineffective drug targets at an earlier stage in the drug development pipeline. Lastly, part III focused on an alternative approach for targeting residual inflammatory risk in atherosclerosis, specifically by targeting the epigenetic machinery that regulates the expression of pro-inflammatory genes

Optimal power control strategy of a distributed energy system incorporating demand response

Abstract: This paper presents an optimal power control scheduling of a distributed energy system in presence of demand response. The distributed energy system comprises of a solar photovoltaic (PV) module and a battery bank storage system. A non-convex mixed binary integer programming technique is used to model flexible and inflexible smart home appliances. Two scenarios are considered in the case study. The results show that efficient scheduling of smart home appliances combined with optimal control of distributed energy system can significantly reduce the total daily electricity cost by more than 50%. The optimal control of distributed energy system was also shown to have an effect on the scheduling of smart home appliances

Towards sustainable energy system options for improving energy access in Southern Africa

Access to modern energy services is one of the pre-requisites to improved livelihood, yet the poor, particularly in developing countries, remain tied to unhealthy and inefficient traditional fuels. Renewable energy technologies are increasingly popular energy supply alternatives to fossil-based fuels in many countries. This study presents sustainable energy system implementation options for increasing energy access in developing countries, with special emphasis on Sub-Saharan Africa. A feasibility case study and various implementation options are presented for possible deployment of these systems. Hybrid optimization of multiple energy resources software was used to simulate and validate the proposed hybrid system design and performance. The simulation results indicate that hybrid systems would be feasible options for distributed generation of electric power for remote locations and areas not connected to the electricity grid. Such a hybrid energy system, through providing modern energy services, gives promise to free-up rural communities to engage in productive activities. The opportunity to power or facilitate productive activities such as agro-processing, fabrication and services can potentially reduce poverty

Matrix-mediated regulation of type 1 collagen synthesis and degradation in cultured fibroblasts

Includes abstract.Includes bibliographical references (leaves 122-157).Stromal cells and the extracellular matrix (ECM) components provide the microenvironment that is pivotal for cell growth, motility, attachment and differentiation. Fibroblasts are some of the cells responsible for the synthesis of most of the extracellular matrix proteins. Type I collagen is the most abundant extracellular matrix protein in the human body and is found in tissues requiring high tensile strength. In this study we investigated the effect of a pre-formed fibroblast-derived extracellular matrix on the expression of type I collagen and associated matrix metalloproteinases in fibroblasts