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Wind power integration on power system reliability and operating reserve capacity
Get PDFThis thesis proposes a WP-HPS cooperation method which utilizes Hydro Pumped Storage (HPS) to cooperate with wind power in order to reduce the impact of wind power characteristics on system reliability, smooth output fluctuation of conventional generation units and maintain system reliability at a required level. Based on the output characteristics of each power generation unit, two control strategies for wind power and pumped storage power stations are proposed.;In addition, the traditional reliability evaluation methods are not applicable to the proposed power system containing HPS and wind power. Therefore, the probability-based reliability assessment method and the reliability cost-benefit analysis method are improved based on the operating characteristics of the proposed power system. These two assessment methods are used to analyze and verify the validity of the two control strategies in improving the reliability of a wind-powered system.;The proposed strategy 2 is applied to three different test systems, and comprehensive analysis in terms of long-term planning and daily operation of the power system at different wind penetration levels is conducted. Simulation experimental results in Chapter 5 show that strategy 2 is more effective than strategy 1 in improving power system reliability. The results in Chapter 6 proved that the WP-HPS cooperation (strategy 2) method can improve the reliability of the power system with a wind penetration level not exceeding 40% to the original level.;The proposed method was finally applied to the actual power system to analyze the proposed method for improving the reliability of the existing system. The evaluation results show that the proposed method not only can meet the requirements of system reliability but also can reduce the wind curtailment rate to the level required by the system.This thesis proposes a WP-HPS cooperation method which utilizes Hydro Pumped Storage (HPS) to cooperate with wind power in order to reduce the impact of wind power characteristics on system reliability, smooth output fluctuation of conventional generation units and maintain system reliability at a required level. Based on the output characteristics of each power generation unit, two control strategies for wind power and pumped storage power stations are proposed.;In addition, the traditional reliability evaluation methods are not applicable to the proposed power system containing HPS and wind power. Therefore, the probability-based reliability assessment method and the reliability cost-benefit analysis method are improved based on the operating characteristics of the proposed power system. These two assessment methods are used to analyze and verify the validity of the two control strategies in improving the reliability of a wind-powered system.;The proposed strategy 2 is applied to three different test systems, and comprehensive analysis in terms of long-term planning and daily operation of the power system at different wind penetration levels is conducted. Simulation experimental results in Chapter 5 show that strategy 2 is more effective than strategy 1 in improving power system reliability. The results in Chapter 6 proved that the WP-HPS cooperation (strategy 2) method can improve the reliability of the power system with a wind penetration level not exceeding 40% to the original level.;The proposed method was finally applied to the actual power system to analyze the proposed method for improving the reliability of the existing system. The evaluation results show that the proposed method not only can meet the requirements of system reliability but also can reduce the wind curtailment rate to the level required by the system
Characterisation of torrefied carbon For carbon dioxide capture and cofiring application
Get PDFIncreased carbon dioxide (CO2) emissions across the globe, and the resulting atmospheric levels, have become the subject of many scientific studies in recent times. Managing and reducing CO2 emissions has remained a challenge for scientists and researchers in carbon capture science, despite technology advancements. Although recent technologies deployed suggest an improvement from the classical approaches, there is a need to explore other alternatives to optimise process performance and to reduce the cost of carbon capture and sequestration processes. In this study, torrefaction technology was employed to develop ‘torrefied carbon’ using renewable carbonaceous materials, such as Iroko (IR - hardwood) and Scottish Pine (SP - softwood), for CO2 capture from the combustion stacks of coal-powered plants. The study was divided into two parts: (a) developing the torrefied carbon using selected torrefaction conditions, at temperatures of (290 °C, 320 °C, 350 °C and 380 °C), a residence time of 60 min and heating rate (10 °C min-1), under CO2 atmosphere. The second is testing the torrefied carbons for CO2 adsorption potential and cofiring applications. The physicochemical characteristics of the torrefied carbons, such as hydrophobicity, calorific values and ultimate analysis, as well as the torrefaction performance indicators, such as energy gain, energy consumption, mass density and mass yield, amongst others, were assessed, allowing the fuel quality and potential use of the torrefied carbon once entirely spent for CO2 capture in same power plant to be evaluated. Given the results obtained, the torrefaction performance indicators showed there is energy gain for the selected torrefaction conditions. The highest energy gain values of 104 and 102 were found for the SP and IR, respectively, at the torrefaction condition of 320 °C, at a residence time of 60 min. The calorific values of the torrefied carbons developed at 320 °C and 350 °C, where - IR (26.49 MJ kg-1 and 26.75 MJ kg-1) and SP (26.13 MJ kg-1 and 29.12 MJ kg-1), respectively, which were higher than those of the low-ranked coal (23.20 MJ kg-1) investigated. For the adsorption studies, the torrefied carbons developed at 350 °C showed the highest CO2 adsorption capacity for both IR and SP carbons. The thermodynamic study of the CO2 adsorption using the Langmuir and isosteric heat of adsorption suggests the existence of heterogeneous surface sites on the torrefied carbon surfaces. The CO2 adsorption shows low heat of adsorption, given the values of the isosteric heat, for IR320 (-45 KJ mol-1), IR350 (-58 KJ mol-1), SP320 (-28 KJ mol-1) and SP350 (-41 KJ mol-1), an indication that the CO2 adsorption process is governed by physisorption. The kinetics of the CO2 adsorption of the torrefied carbons followed the Double Exponential Model, described by two distinct rate-determining steps. The rate of CO2 adsorption on the torrefied carbons appeared fast, given the equilibration time of an average of < 8 min for the IR and 11 min for the SP carbon, suggesting that the short time of equilibrium based on the Pressure Swing Adsorption process indicates a good potential from the materials on a kinetic basis. Within the study context, it was determined that the torrefied carbons could be employed for cofiring in coal-powered plants following a CO2 capture process. Although the structural features exhibited by the torrefied carbons were not fully explored in this work, due to the research limitations, the study opens up an opportunity into the potentials of torrefied carbon utilisation as a cost-intensive alternative in CCS applications.Increased carbon dioxide (CO2) emissions across the globe, and the resulting atmospheric levels, have become the subject of many scientific studies in recent times. Managing and reducing CO2 emissions has remained a challenge for scientists and researchers in carbon capture science, despite technology advancements. Although recent technologies deployed suggest an improvement from the classical approaches, there is a need to explore other alternatives to optimise process performance and to reduce the cost of carbon capture and sequestration processes. In this study, torrefaction technology was employed to develop ‘torrefied carbon’ using renewable carbonaceous materials, such as Iroko (IR - hardwood) and Scottish Pine (SP - softwood), for CO2 capture from the combustion stacks of coal-powered plants. The study was divided into two parts: (a) developing the torrefied carbon using selected torrefaction conditions, at temperatures of (290 °C, 320 °C, 350 °C and 380 °C), a residence time of 60 min and heating rate (10 °C min-1), under CO2 atmosphere. The second is testing the torrefied carbons for CO2 adsorption potential and cofiring applications. The physicochemical characteristics of the torrefied carbons, such as hydrophobicity, calorific values and ultimate analysis, as well as the torrefaction performance indicators, such as energy gain, energy consumption, mass density and mass yield, amongst others, were assessed, allowing the fuel quality and potential use of the torrefied carbon once entirely spent for CO2 capture in same power plant to be evaluated. Given the results obtained, the torrefaction performance indicators showed there is energy gain for the selected torrefaction conditions. The highest energy gain values of 104 and 102 were found for the SP and IR, respectively, at the torrefaction condition of 320 °C, at a residence time of 60 min. The calorific values of the torrefied carbons developed at 320 °C and 350 °C, where - IR (26.49 MJ kg-1 and 26.75 MJ kg-1) and SP (26.13 MJ kg-1 and 29.12 MJ kg-1), respectively, which were higher than those of the low-ranked coal (23.20 MJ kg-1) investigated. For the adsorption studies, the torrefied carbons developed at 350 °C showed the highest CO2 adsorption capacity for both IR and SP carbons. The thermodynamic study of the CO2 adsorption using the Langmuir and isosteric heat of adsorption suggests the existence of heterogeneous surface sites on the torrefied carbon surfaces. The CO2 adsorption shows low heat of adsorption, given the values of the isosteric heat, for IR320 (-45 KJ mol-1), IR350 (-58 KJ mol-1), SP320 (-28 KJ mol-1) and SP350 (-41 KJ mol-1), an indication that the CO2 adsorption process is governed by physisorption. The kinetics of the CO2 adsorption of the torrefied carbons followed the Double Exponential Model, described by two distinct rate-determining steps. The rate of CO2 adsorption on the torrefied carbons appeared fast, given the equilibration time of an average of < 8 min for the IR and 11 min for the SP carbon, suggesting that the short time of equilibrium based on the Pressure Swing Adsorption process indicates a good potential from the materials on a kinetic basis. Within the study context, it was determined that the torrefied carbons could be employed for cofiring in coal-powered plants following a CO2 capture process. Although the structural features exhibited by the torrefied carbons were not fully explored in this work, due to the research limitations, the study opens up an opportunity into the potentials of torrefied carbon utilisation as a cost-intensive alternative in CCS applications
A face to die for : acne, dermatology, and the quest for perfect skin in Britain and the United States, c.1800–present
Get PDFAcne is a blight on the social and emotional lives of many adolescents, often leaving both physical and psychological scars. Acne also carries a financial burden, with chronic unemployment being endemic amongst sufferers, costing over 3 billion dollars per year in direct and indirect health care costs in the US alone. But how far have adolescents, physicians and pharmaceutical companies been willing to go in order to treat it? This project addresses this question by providing the first history of acne. Drawing on unpublished archival material, medical literature, media sources, drug advertisements and oral history interviews, it charts how acne became the subject of medical concern from the nineteenth century onwards and explores how physicians and patients understood its causes and treatments. It examines the way physicians and pharmaceutical companies turned to the perceived health needs of adolescent patients and analyses how the risks and benefits of teratogenic drugs like Accutane were perceived by patients and physicians. It promises to add to the emergent historiography of skin and adolescent health, as well as to our understanding of the lived experience of those with acne. Finally, the project will engage with ongoing debates in the UK about whether Accutane (Roaccutane) should be sold in the UK and how drug policy should be informed more generally.Acne is a blight on the social and emotional lives of many adolescents, often leaving both physical and psychological scars. Acne also carries a financial burden, with chronic unemployment being endemic amongst sufferers, costing over 3 billion dollars per year in direct and indirect health care costs in the US alone. But how far have adolescents, physicians and pharmaceutical companies been willing to go in order to treat it? This project addresses this question by providing the first history of acne. Drawing on unpublished archival material, medical literature, media sources, drug advertisements and oral history interviews, it charts how acne became the subject of medical concern from the nineteenth century onwards and explores how physicians and patients understood its causes and treatments. It examines the way physicians and pharmaceutical companies turned to the perceived health needs of adolescent patients and analyses how the risks and benefits of teratogenic drugs like Accutane were perceived by patients and physicians. It promises to add to the emergent historiography of skin and adolescent health, as well as to our understanding of the lived experience of those with acne. Finally, the project will engage with ongoing debates in the UK about whether Accutane (Roaccutane) should be sold in the UK and how drug policy should be informed more generally
Microfluidic manufacturing and development of a liposomal vaccine for Clostridium difficile
Get PDFOral vaccines offer significant social and economic advantages over vaccines delivered by parenteral routes including higher patient compliance and ease of administration, allowing vaccines to be given by health workers without medical training. Furthermore, oral immunisation can generate both systemic and localised immune responses, making it ideal for generating effective protection against many enteric pathogens such as the gram-positive spore forming bacterium Clostridium difficile (C. difficile). However, design of an effective vaccine for oral administration remains a significant challenge. In order to reach the relevant sites for the induction of immunological responses, the vaccine must first traverse the hostile environment of the gastrointestinal tract (GIT).;For subunit antigens, the acidic pH, degradative enzymes and bile salts present in the GIT can adversely impact their structural stability. This can limit the effectiveness of the immune response. In addition, the mucosal surface within the gut can impair the transport of the vaccine antigen and limit the accessibility to the underlying antigen presenting cells. In order to circumvent these barriers, delivery systems can be employed. Lipid-based delivery systems are commonly used to deliver therapeutics via the oral route of administration. Of the lipid based systems, liposomes have been widely investigated but tend to be used for parenteral delivery.;Therefore, the aim of the work in this thesis was to explore the use of liposomes for the oral delivery of a C.difficile vaccine. Liposomes generally exhibit low toxicity, enhance interactions with biological membranes and can be incredibly versatile in regards to what compounds they can incorporate (whether they are encapsulated within the aqueous core, within the lipid bilayer or surface associated). However, the manufacture of liposomes has been limited to batch scale production which has inherent risk associated. By employing microfluidics as a manufacturing platform, in conjunction with tangential flow filtration for purification, scalable production can be achieved.;Therefore, this method was employed for the formulation and manufacture of the liposomal vaccine systems. Key production parameters were identified and formulations were selected based upon their physicochemical characteristics and protein loading efficiency. Selected formulations were screened for immunological effectiveness on THP-1 macrophage-like cells regarding antigen processing ability and activation marker expression. Finally, a range of formulations were then administered orally to mice to determine in vivo efficacy.;Enhanced antibody responses (IgG) could be observed when antigen was administered encapsulated within liposomal formulation DSPC:Chol (alongside the potent adjuvant cholera toxin) when compared to free antigen alone; however, poor localised IgA responses were observed for all liposomal formulations tested. The work within this thesis presents a platform for the rapid and scalable manufacture, purification and at-line analysis of liposomal formulations incorporating protein, de-risking the translation of liposomal based protein products from bench to large scale production.Oral vaccines offer significant social and economic advantages over vaccines delivered by parenteral routes including higher patient compliance and ease of administration, allowing vaccines to be given by health workers without medical training. Furthermore, oral immunisation can generate both systemic and localised immune responses, making it ideal for generating effective protection against many enteric pathogens such as the gram-positive spore forming bacterium Clostridium difficile (C. difficile). However, design of an effective vaccine for oral administration remains a significant challenge. In order to reach the relevant sites for the induction of immunological responses, the vaccine must first traverse the hostile environment of the gastrointestinal tract (GIT).;For subunit antigens, the acidic pH, degradative enzymes and bile salts present in the GIT can adversely impact their structural stability. This can limit the effectiveness of the immune response. In addition, the mucosal surface within the gut can impair the transport of the vaccine antigen and limit the accessibility to the underlying antigen presenting cells. In order to circumvent these barriers, delivery systems can be employed. Lipid-based delivery systems are commonly used to deliver therapeutics via the oral route of administration. Of the lipid based systems, liposomes have been widely investigated but tend to be used for parenteral delivery.;Therefore, the aim of the work in this thesis was to explore the use of liposomes for the oral delivery of a C.difficile vaccine. Liposomes generally exhibit low toxicity, enhance interactions with biological membranes and can be incredibly versatile in regards to what compounds they can incorporate (whether they are encapsulated within the aqueous core, within the lipid bilayer or surface associated). However, the manufacture of liposomes has been limited to batch scale production which has inherent risk associated. By employing microfluidics as a manufacturing platform, in conjunction with tangential flow filtration for purification, scalable production can be achieved.;Therefore, this method was employed for the formulation and manufacture of the liposomal vaccine systems. Key production parameters were identified and formulations were selected based upon their physicochemical characteristics and protein loading efficiency. Selected formulations were screened for immunological effectiveness on THP-1 macrophage-like cells regarding antigen processing ability and activation marker expression. Finally, a range of formulations were then administered orally to mice to determine in vivo efficacy.;Enhanced antibody responses (IgG) could be observed when antigen was administered encapsulated within liposomal formulation DSPC:Chol (alongside the potent adjuvant cholera toxin) when compared to free antigen alone; however, poor localised IgA responses were observed for all liposomal formulations tested. The work within this thesis presents a platform for the rapid and scalable manufacture, purification and at-line analysis of liposomal formulations incorporating protein, de-risking the translation of liposomal based protein products from bench to large scale production
Safety culture, enhancing shipping safety through better near miss reporting
Get PDFThis thesis was previously held under moratorium from 24th November 2020 until 24th November 2024.The history of the maritime industry is full of catastrophic accidents. These accidents are attributed to human and organisational factors. The new trend for the enhancement of shipping safety is by increasing the Safety Culture of the shipping industry. Thus, implementing an effective Safety Culture mitigates the feasibility of the reoccurrence of the same unsafe acts. Such an implementation is a requirement by the International Safety Management (ISM) Code. The ISM code also requires shipping companies to develop a system for reporting ‘Near Misses’ as they are the root causes of any catastrophic accident. However, the ISM Code does not provide a standardised method for the Near Miss Reporting (NMR) system. This leads the shipping companies to create their own system without paying attention to the impact and without taking the maximum advantage of the lessons learned. Therefore, this thesis aims to develop a novel and standardised NMR System that helps to enhance the overall Safety Culture as the NMR is considered a tool to identify the human weaknesses in the socio-technical system and to manage them to mitigate the reoccurrence of the similar gaps. This aim was achieved via conducting NMR assessment through interviews of the key personnel in a shipping company and a reporting culture questionnaire, which was distributed among the seafarers at the same shipping company. Another method, which is utilised to measure the leading factors that influence the NMR, is the KPI assessment for the same shipping company. After gathering those data, a newly designed NMR form and framework were proposed and tested via a confidential link among the company crew to compare its outcome with the existing reporting form. When all the assessments were completed, and all the data was gathered, appropriate analyses were conducted to identify the gaps and to propose solutions for them. Those methods have resulted in existence of the blame culture at the shipping company and the existing NMR system at the shipping company requires significant improvement. The ineffective NMR system at the shipping company leadsto unexpected KPIs result.The history of the maritime industry is full of catastrophic accidents. These accidents are attributed to human and organisational factors. The new trend for the enhancement of shipping safety is by increasing the Safety Culture of the shipping industry. Thus, implementing an effective Safety Culture mitigates the feasibility of the reoccurrence of the same unsafe acts. Such an implementation is a requirement by the International Safety Management (ISM) Code. The ISM code also requires shipping companies to develop a system for reporting ‘Near Misses’ as they are the root causes of any catastrophic accident. However, the ISM Code does not provide a standardised method for the Near Miss Reporting (NMR) system. This leads the shipping companies to create their own system without paying attention to the impact and without taking the maximum advantage of the lessons learned. Therefore, this thesis aims to develop a novel and standardised NMR System that helps to enhance the overall Safety Culture as the NMR is considered a tool to identify the human weaknesses in the socio-technical system and to manage them to mitigate the reoccurrence of the similar gaps. This aim was achieved via conducting NMR assessment through interviews of the key personnel in a shipping company and a reporting culture questionnaire, which was distributed among the seafarers at the same shipping company. Another method, which is utilised to measure the leading factors that influence the NMR, is the KPI assessment for the same shipping company. After gathering those data, a newly designed NMR form and framework were proposed and tested via a confidential link among the company crew to compare its outcome with the existing reporting form. When all the assessments were completed, and all the data was gathered, appropriate analyses were conducted to identify the gaps and to propose solutions for them. Those methods have resulted in existence of the blame culture at the shipping company and the existing NMR system at the shipping company requires significant improvement. The ineffective NMR system at the shipping company leadsto unexpected KPIs result
Achieving quality medical equipment in developing countries through remanufacturing
Get PDFRemanufacturing restores a used product to at least, its original equipment manufacturers (OEM) performance specification from the customer’s perspective and gives the resultant product a warranty that is at least equal to that of newly manufactured equivalent product. It is a wise option as it offers high quality products at lower price since remanufactured products are substantially cheaper than new products of equivalent quality. Remanufacturing also has social, economic, and environmental benefits since it has the potential to become a source of revenue, create jobs and reduce environmental pollution. While remanufacturing is common in industries such as automobile and aviation, its application and benefits in the medical device industry have not been investigated.Medical devices are crucial in the diagnosis and treatment of diseases and injuries but are inequitably distributed globally, such that there is acute shortage in developing countries with consequent high mortality rates over disease and adverse health conditions that could be treated if the right equipment were available. Several strategies have been considered to eliminate or mitigate this issue. However, neither has remanufacturing been considered a potential solution to this issue nor key factors in implementing medical equipment remanufacturing for developing countries been identified. This study proposes remanufacturing as a potential sustainable solution to this issue.The research was conducted in 3 phases following a multiphase mixed methods design. Questionnaires and interviews were used to gather data while pre-figured thematic analysis, Decision-making trial and evaluation laboratory (DEMATEL) technique and confirmatory factor analysis techniques were used to analyse the data. Main findings of this research include the following: (1) medical equipment remanufacturing can address 5 out of 11 causes of poor medical equipment availability accounting for 43.5% of the overall prominence. (2) A definition and decision support frameworks for medical equipment remanufacturing that could help to improve availability of quality medical equipment in developing countries (3) Major concerns in implementing medical equipment remanufacturing. (4) Impact of perception on the purchase intention for remanufactured medical equipment.This research is the first to identify the potential impact of remanufacturing in addressing medical equipment availability issues in developing countries, to characterise medical equipment remanufacturing towards this end. It is unique in its application of DEMATEL to the study of root causes of poor availability of medical equipment in developing countries and in applying behavioural science in understanding its purchase intentions.Remanufacturing restores a used product to at least, its original equipment manufacturers (OEM) performance specification from the customer’s perspective and gives the resultant product a warranty that is at least equal to that of newly manufactured equivalent product. It is a wise option as it offers high quality products at lower price since remanufactured products are substantially cheaper than new products of equivalent quality. Remanufacturing also has social, economic, and environmental benefits since it has the potential to become a source of revenue, create jobs and reduce environmental pollution. While remanufacturing is common in industries such as automobile and aviation, its application and benefits in the medical device industry have not been investigated.Medical devices are crucial in the diagnosis and treatment of diseases and injuries but are inequitably distributed globally, such that there is acute shortage in developing countries with consequent high mortality rates over disease and adverse health conditions that could be treated if the right equipment were available. Several strategies have been considered to eliminate or mitigate this issue. However, neither has remanufacturing been considered a potential solution to this issue nor key factors in implementing medical equipment remanufacturing for developing countries been identified. This study proposes remanufacturing as a potential sustainable solution to this issue.The research was conducted in 3 phases following a multiphase mixed methods design. Questionnaires and interviews were used to gather data while pre-figured thematic analysis, Decision-making trial and evaluation laboratory (DEMATEL) technique and confirmatory factor analysis techniques were used to analyse the data. Main findings of this research include the following: (1) medical equipment remanufacturing can address 5 out of 11 causes of poor medical equipment availability accounting for 43.5% of the overall prominence. (2) A definition and decision support frameworks for medical equipment remanufacturing that could help to improve availability of quality medical equipment in developing countries (3) Major concerns in implementing medical equipment remanufacturing. (4) Impact of perception on the purchase intention for remanufactured medical equipment.This research is the first to identify the potential impact of remanufacturing in addressing medical equipment availability issues in developing countries, to characterise medical equipment remanufacturing towards this end. It is unique in its application of DEMATEL to the study of root causes of poor availability of medical equipment in developing countries and in applying behavioural science in understanding its purchase intentions
Mental health literacy and intended help-seeking in adolescence
Get PDFThis study investigates the extent to which personal stigma mediates the relationship between mental health literacy (MHL) and intended help-seeking in adolescence, and whether perceived stigma from specific groups (parents and friends) moderates these relationships. Additionally, the study examines whether age, gender, and socioeconomic status (SES) moderate associations between MHL, stigma and intended help-seeking. A theoretical framework is proposed and tested which draws on the Knowledge-Attitude Behaviour model (KAB) and incorporates subjective norms (Theory of Planned Behaviour, Ajzen, 1991; 1988), which are known to be particularly predictive of adolescent behaviour. The proposed framework of mental health literacy, stigma and help-seeking in adolescence was formulated to provide a possible explanation for known associations between MHL and help seeking despite a well evidenced gap between knowledge and behaviour. The framework proposes that MHL (knowledge), informs personal stigma (attitude) which informs intended helpseeking (behaviour).;It further proposes that perceived stigma from friends and parents (subjective norms) moderate associations between knowledge, attitude, and behaviour. A cross-sectional survey was administered to 12-17 year olds (n = 734) and data were analysed using Structural Equation Modelling (SEM). Results indicated that MHL reduced personal stigma, but different forms of MHL were associated with both increased and decreased help seeking intention, which represents a unique finding in the literature. Personal stigma did not mediate relationships in the model. Perceived stigmas acted as moderators, while demographic characteristics did not, indicating that the model holds well regardless of age, gender and SES. Based on findings it is suggested that to improve help-seeking, MHL interventions focus on effective treatments rather than on information and identification of mental health problems. Findings also demonstrated that MHL was most associated with help-seeking intention when perceived stigma was high. Therefore, it is further suggested that both peers and parents be incorporated into school-based interventions aiming to increase MHL, reduce perceived stigma and promote help-seeking.This study investigates the extent to which personal stigma mediates the relationship between mental health literacy (MHL) and intended help-seeking in adolescence, and whether perceived stigma from specific groups (parents and friends) moderates these relationships. Additionally, the study examines whether age, gender, and socioeconomic status (SES) moderate associations between MHL, stigma and intended help-seeking. A theoretical framework is proposed and tested which draws on the Knowledge-Attitude Behaviour model (KAB) and incorporates subjective norms (Theory of Planned Behaviour, Ajzen, 1991; 1988), which are known to be particularly predictive of adolescent behaviour. The proposed framework of mental health literacy, stigma and help-seeking in adolescence was formulated to provide a possible explanation for known associations between MHL and help seeking despite a well evidenced gap between knowledge and behaviour. The framework proposes that MHL (knowledge), informs personal stigma (attitude) which informs intended helpseeking (behaviour).;It further proposes that perceived stigma from friends and parents (subjective norms) moderate associations between knowledge, attitude, and behaviour. A cross-sectional survey was administered to 12-17 year olds (n = 734) and data were analysed using Structural Equation Modelling (SEM). Results indicated that MHL reduced personal stigma, but different forms of MHL were associated with both increased and decreased help seeking intention, which represents a unique finding in the literature. Personal stigma did not mediate relationships in the model. Perceived stigmas acted as moderators, while demographic characteristics did not, indicating that the model holds well regardless of age, gender and SES. Based on findings it is suggested that to improve help-seeking, MHL interventions focus on effective treatments rather than on information and identification of mental health problems. Findings also demonstrated that MHL was most associated with help-seeking intention when perceived stigma was high. Therefore, it is further suggested that both peers and parents be incorporated into school-based interventions aiming to increase MHL, reduce perceived stigma and promote help-seeking
Regulated generation allocation and operation optimization for networks with new variable independent power production and self-generation
Get PDFThe world is moving towards legally binding targets for decarbonisation, with considerable interest in cost effective energy pathways that will have positive socio-economic, environmental and health impacts. The electricity sector is progressing by adopting renewable energy as a replacement for fossil fuel-based electricity generation. As renewable energy sources (RES) in the form of independent power production (IPP) and on-site or self-generation (SG) proliferate on power networks, questions arise about their impact on the financial integrity of the traditional power distribution business. As distribution companies (DISCOs) act to protect their own financial interests, network access barriers will be presented to emerging RES. Network regulation is expected to drive DISCOs to pursue a more socially desirable outcome.;However, today's methods of network regulation are not adequate enough to remove the barriers and still ensure renewable energy goals are met. In fact there are no widely-accepted and clear mechanisms to encourage DISCOs to coordinate distributed generation, let alone SG and IPP, integration in a cost-effective manner. In terms of policy, companies can be obligated to meet a quota of RES in their energy supply. But this obligation is usually not guaranteed to align with the capabilities of power networks, which typically suffer from voltage and congestion constraints among others. To set achievable quotas there is a need for a more adaptable mechanism that takes into account capacity constraints.;The work of this thesis concerns the formulation and empirical analyses of optimisation models of structured RES allocation by a regulated DISCO, and the regulating authority's role in influencing the DISCO's planning approach and promoting socially desirable performance. The developed optimisation models uniquely: introduce combined SG and IPP allocation, which allows generation to be defined in association with on-site demand; provide generation capacity that simultaneously meets network, policy and regulatory requirements (i.e. there is no need to individually evaluate the same implications from the calculated capacity); take account of generation curtailment and its underlying restrictions for SG and IPP; demonstrate SG and IPP allocations for range of quota obligations; and benchmark the performance of the models against alternative approaches of generation allocation and regulation.;This results in a problem with a multilevel structure necessitating the computation of spatial capacity and a solution to the multi-period optimal power flow. The problem variables further depend on the perspective of stakeholders in the electricity market. From the viewpoint of the DISCO, the solution intends to provide suitably sited DG capacity and maximise profit. As for the regulating authority the results offer the most suitable reward or penalty to drive the DISCO towards a low carbon network.In response, the regulated DISCO should then carry out DG planning in line with broader goals of society. This joint SG and IPP integration problem lends itself specific and unique constraints including generation class-specific net generation and energy curtailment.;The results reported in this thesis highlight the value and performance of the DISCO and regulation optimisation models on several power networks of varying size and composition. Numerical experiments demonstrate the developed DISCO optimisation model outperforms standard models, concerned primarily with capacity maximisation, in satisfying the following binding constraints: minimum IPP capacity and SG net energy.It is further revealed that integrating SG and IPP in a benchmark system with the proposed model increases profit by up to 23.7%, adding an improvement of 8% over a feasible standard model. In a case study of a network with extremely limited capacity-insufficient for minimum IPP-it is shown using the regulation optimisation model that to maintain the required DISCO profit the incentives can range from 2% to 14% of revenue for quota obligations spanning 10% to 50% of network load. The regulation optimisation model is compared with decoupling, a familiar method for removing energy retail impacts on revenue. Results show that regulation optimisation model is able to maintain a steadier profit with increasing quota requirements.The world is moving towards legally binding targets for decarbonisation, with considerable interest in cost effective energy pathways that will have positive socio-economic, environmental and health impacts. The electricity sector is progressing by adopting renewable energy as a replacement for fossil fuel-based electricity generation. As renewable energy sources (RES) in the form of independent power production (IPP) and on-site or self-generation (SG) proliferate on power networks, questions arise about their impact on the financial integrity of the traditional power distribution business. As distribution companies (DISCOs) act to protect their own financial interests, network access barriers will be presented to emerging RES. Network regulation is expected to drive DISCOs to pursue a more socially desirable outcome.;However, today's methods of network regulation are not adequate enough to remove the barriers and still ensure renewable energy goals are met. In fact there are no widely-accepted and clear mechanisms to encourage DISCOs to coordinate distributed generation, let alone SG and IPP, integration in a cost-effective manner. In terms of policy, companies can be obligated to meet a quota of RES in their energy supply. But this obligation is usually not guaranteed to align with the capabilities of power networks, which typically suffer from voltage and congestion constraints among others. To set achievable quotas there is a need for a more adaptable mechanism that takes into account capacity constraints.;The work of this thesis concerns the formulation and empirical analyses of optimisation models of structured RES allocation by a regulated DISCO, and the regulating authority's role in influencing the DISCO's planning approach and promoting socially desirable performance. The developed optimisation models uniquely: introduce combined SG and IPP allocation, which allows generation to be defined in association with on-site demand; provide generation capacity that simultaneously meets network, policy and regulatory requirements (i.e. there is no need to individually evaluate the same implications from the calculated capacity); take account of generation curtailment and its underlying restrictions for SG and IPP; demonstrate SG and IPP allocations for range of quota obligations; and benchmark the performance of the models against alternative approaches of generation allocation and regulation.;This results in a problem with a multilevel structure necessitating the computation of spatial capacity and a solution to the multi-period optimal power flow. The problem variables further depend on the perspective of stakeholders in the electricity market. From the viewpoint of the DISCO, the solution intends to provide suitably sited DG capacity and maximise profit. As for the regulating authority the results offer the most suitable reward or penalty to drive the DISCO towards a low carbon network.In response, the regulated DISCO should then carry out DG planning in line with broader goals of society. This joint SG and IPP integration problem lends itself specific and unique constraints including generation class-specific net generation and energy curtailment.;The results reported in this thesis highlight the value and performance of the DISCO and regulation optimisation models on several power networks of varying size and composition. Numerical experiments demonstrate the developed DISCO optimisation model outperforms standard models, concerned primarily with capacity maximisation, in satisfying the following binding constraints: minimum IPP capacity and SG net energy.It is further revealed that integrating SG and IPP in a benchmark system with the proposed model increases profit by up to 23.7%, adding an improvement of 8% over a feasible standard model. In a case study of a network with extremely limited capacity-insufficient for minimum IPP-it is shown using the regulation optimisation model that to maintain the required DISCO profit the incentives can range from 2% to 14% of revenue for quota obligations spanning 10% to 50% of network load. The regulation optimisation model is compared with decoupling, a familiar method for removing energy retail impacts on revenue. Results show that regulation optimisation model is able to maintain a steadier profit with increasing quota requirements
Putting (programme) theory into practice, the use of programme theory in programme evaluation practice in small third sector organisations. Current practice and future improvements
Get PDFThe theory-practice gaps in the field of evaluation demand evaluation. Research on evaluation aims to address these gaps. Specifically, this thesis focuses on the use of programme theory in the context of programme evaluation practice in small third sector organisations. In this context, social programming efforts and programme evaluation are critical to ensure the effective design, and implementation of programmes and services for the individuals, groups, and communities that small third sector organisations work with. Despite the importance of social programming and programme evaluation in this setting, there are numerous contextual challenges facing programme evaluation practice.;This thesis highlights that how we conceptualise evaluation practice has implications for how we might go about conducting research on evaluation practice: such implications relate to the focus of the research and the methodological framework used. I find that the literature on the use of programme theory in evaluation practice is not consistent with our understanding of programme evaluation practice in small third sector organisations.;As such, I use the empirical component of this thesis to explore the use of programme theory in the context of programme evaluation practice in small third sector organisations from a 'practitioner-oriented perspective'. I address two research questions about current practice in the use of programme theory in small third sector organisations, and about how the development of programme theory can improve future programme evaluation practice in this setting. I adopt a multi-methodological framework to address the research questions.;In terms of current practice, I find that much of the understanding and use of programme theory in small third sector organisations can be considered as tacit in nature. I also find that, whilst there may be challenges in making knowledge which is tacit in nature, explicit, that programme theory is not used explicitly in formal, or systematic, programme evaluation activities. This is also partly due to other factors including, practical constraints, and the fact that the use of programme theory is not explicitly asked for by funders. In terms of improving future practice, I find that the development of programme theory has two primary roles in helping evaluators think more purposefully and constructively about programme implementation and outcome evaluation: that is, in its role as a 'tool for evaluative thinking', through its confirmatory function and visual nature.;Overall, this thesis contributes to our understanding of the use of programme theory in small third sector organisations in terms of the better conceptualising current practice, as well as understanding how the development of programme theory can improve future programme evaluation practices in this setting.These contributions have implications for programme evaluation theory and practice in small third sector organisations, and for research on evaluation more generally.The theory-practice gaps in the field of evaluation demand evaluation. Research on evaluation aims to address these gaps. Specifically, this thesis focuses on the use of programme theory in the context of programme evaluation practice in small third sector organisations. In this context, social programming efforts and programme evaluation are critical to ensure the effective design, and implementation of programmes and services for the individuals, groups, and communities that small third sector organisations work with. Despite the importance of social programming and programme evaluation in this setting, there are numerous contextual challenges facing programme evaluation practice.;This thesis highlights that how we conceptualise evaluation practice has implications for how we might go about conducting research on evaluation practice: such implications relate to the focus of the research and the methodological framework used. I find that the literature on the use of programme theory in evaluation practice is not consistent with our understanding of programme evaluation practice in small third sector organisations.;As such, I use the empirical component of this thesis to explore the use of programme theory in the context of programme evaluation practice in small third sector organisations from a 'practitioner-oriented perspective'. I address two research questions about current practice in the use of programme theory in small third sector organisations, and about how the development of programme theory can improve future programme evaluation practice in this setting. I adopt a multi-methodological framework to address the research questions.;In terms of current practice, I find that much of the understanding and use of programme theory in small third sector organisations can be considered as tacit in nature. I also find that, whilst there may be challenges in making knowledge which is tacit in nature, explicit, that programme theory is not used explicitly in formal, or systematic, programme evaluation activities. This is also partly due to other factors including, practical constraints, and the fact that the use of programme theory is not explicitly asked for by funders. In terms of improving future practice, I find that the development of programme theory has two primary roles in helping evaluators think more purposefully and constructively about programme implementation and outcome evaluation: that is, in its role as a 'tool for evaluative thinking', through its confirmatory function and visual nature.;Overall, this thesis contributes to our understanding of the use of programme theory in small third sector organisations in terms of the better conceptualising current practice, as well as understanding how the development of programme theory can improve future programme evaluation practices in this setting.These contributions have implications for programme evaluation theory and practice in small third sector organisations, and for research on evaluation more generally
Design of 2D sparse array transducers for anomaly detection associated with a transcranial ultrasound system
Get PDFUltrasound imaging is a low cost and non-invasive technique, with many biomedical and industrial applications. In many applications, operator dependency can significantly influence the quality of the acquired information. Transcranial ultrasound is one such application, and this Thesis will investigate both transducer design and image processing techniques inspired by the desire to improve the ability of an ultrasonic system to detect and size anomalies in the blood flow. Aperiodic sparse 2D ultrasonic array configurations, including random array, log spiral array, and sunflower spiral array, have been considered for their potential as a conformable transducer able to image within a focal range of 30-80 mm, at an operating frequency of 2 MHz. Optimisation of the imaging performance of potential array patterns has been undertaken based on their simulated far field directivity functions.;Subsequently, two log spiral array patterns have been selected: one is the overall optimal design; the other is a compromise design to accommodate in-house manufacturing limitations. Both conventional 1-3 (C13) piezocomposite and piezoceramic fibre Composite Element Composite Array Transducer (CECAT) structures have been fabricated and characterised. The CECAT device provides a conformable piezocomposite material and demonstrated reduced mechanical cross-talk between neighbouring array elements and improved the operational bandwidth, while the mechanically stiff C13 devices perform better in terms of sensitivity. Moreover, the C13 device incorporating the overall optimal array pattern performs best in terms of the image background noise level, while for transducers based on the compromise design, the CECAT device offers better axial resolution when imaging multiple reflectors.;Image processing algorithms, such as Hough transform and Morphological Opening, have been implemented to automatically detect and dimension particles located within a fluid-filled tube structure, in a variety of experimental scenarios. This includes bespoke phantoms using tissue mimicking material to simulate a basic transcranial ultrasound arrangement. The image processing algorithms were initially developed using data collected from a commercial 1D linear array transducer. Subsequent experiments using the fabricated CECAT log spiral 2D array transducer demonstrated that this algorithmic approach was able to detect the walls of the tube structure and stationary anomalies within the tube with a precision of ~0.1 mm.Ultrasound imaging is a low cost and non-invasive technique, with many biomedical and industrial applications. In many applications, operator dependency can significantly influence the quality of the acquired information. Transcranial ultrasound is one such application, and this Thesis will investigate both transducer design and image processing techniques inspired by the desire to improve the ability of an ultrasonic system to detect and size anomalies in the blood flow. Aperiodic sparse 2D ultrasonic array configurations, including random array, log spiral array, and sunflower spiral array, have been considered for their potential as a conformable transducer able to image within a focal range of 30-80 mm, at an operating frequency of 2 MHz. Optimisation of the imaging performance of potential array patterns has been undertaken based on their simulated far field directivity functions.;Subsequently, two log spiral array patterns have been selected: one is the overall optimal design; the other is a compromise design to accommodate in-house manufacturing limitations. Both conventional 1-3 (C13) piezocomposite and piezoceramic fibre Composite Element Composite Array Transducer (CECAT) structures have been fabricated and characterised. The CECAT device provides a conformable piezocomposite material and demonstrated reduced mechanical cross-talk between neighbouring array elements and improved the operational bandwidth, while the mechanically stiff C13 devices perform better in terms of sensitivity. Moreover, the C13 device incorporating the overall optimal array pattern performs best in terms of the image background noise level, while for transducers based on the compromise design, the CECAT device offers better axial resolution when imaging multiple reflectors.;Image processing algorithms, such as Hough transform and Morphological Opening, have been implemented to automatically detect and dimension particles located within a fluid-filled tube structure, in a variety of experimental scenarios. This includes bespoke phantoms using tissue mimicking material to simulate a basic transcranial ultrasound arrangement. The image processing algorithms were initially developed using data collected from a commercial 1D linear array transducer. Subsequent experiments using the fabricated CECAT log spiral 2D array transducer demonstrated that this algorithmic approach was able to detect the walls of the tube structure and stationary anomalies within the tube with a precision of ~0.1 mm
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