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Phytochemical, anti-cancer, anti-inflammatory and neuroprotective studies on compounds isolated from Malaysian plants, Aquilaria malaccensis and Hopea dryobalanoides
Get PDFNatural products have been used for medicinal purposes for centuries and remain the main source of new drugs to treat diseases due to their biological activities such as anticancer, anti-inflammatory and neuroprotective effects. This thesis aimed to : 1) isolate bioactive compounds from two Malaysian plants which are: Aquilaria malaccensis and Hopea dryobalanoides using column chromatography and characterised them by nuclear magnetic resonance (NMR); 2) assess the anti-cancer activity of the isolated compounds through various in vitro assays and metabolomics profiling; 3) investigate the anti-inflammatory properties of the compounds by inhibition of the pro-inflammatory cytokines (tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6)) levels in response to lipopolysaccharide (LPS) stimulation in macrophage cells and identify the effects of the compound treatments on the gene expression against the inflammatory response caused by LPS-stimulated macrophage cells; 4) examine the protective effects of the compounds against oxidative stress induced in neuron cells.1) Plants extracts, investigated phytochemically, resulted in the isolation of 7-methoxyacacetin (7-aca) from the hexane extract of A. malaccensis twigs for the first time, a mixture of two compounds quercitrin and afzelin (Q/A) from the methanol extract of A. malaccensis twigs and two compounds named balanocarpol (bala) and heimiol A from the ethyl acetate extract of H. dryobalanoides bark. There are limited reports on the biological activity of 7-aca, however a similar compound called acacetin (aca) has been reported to have a range of bioactivates including anti-cancer, anti-inflammatory and protective effects. Therefore, aca was purchased commercially for comparison purposes.;2) Cytotoxicity screening of 7-aca, aca, Q/A and bala resulted in decreased viability of A2780 (ovarian) and ZR-75-1 (breast) cells in a concentration dependant manner. 7-Aca exhibited a more potent cytotoxicity against A2780 and ZR-75-1 cells (IC50=7.9µM and 8.5µM, respectively) compared to aca (IC50= 19.5µM and 17.5µM,respectively). Heimiol A did not show toxic effects against both cancer cells even at the highest concentration (150µM). All compounds showed selective toxicity toward the cancers cells, as they did not cause toxicity against normal PNT2A (prostate) cells. Further investigation behind the cytotoxic effect of the compounds revealed that 7-aca,aca, Q/A and bala caused the production of ROS, depletion of mitochondria membrane potential (ΔΨM) and an increase in caspase-3/7 levels in A2780 and ZR-75-1 cells. Many studies have reported that an excessive increase in ROS in cancer cells disrupts the mitochondrial membrane thus causing the loss of ΔΨM that leads to activation of effectors such as caspase-3, which eventually result in apoptotic cell death. Moreover,7-aca showed the strongest anti-metastatic effects through the inhibition of adhesion of cancer cells to the ECM protein fibronectin as well as inhibiting the migration and invasion of A2780 and ZR-75-1 cells by approximately 50-70%. The overall results revealed that 7-aca showed a stronger anti-cancer effects towards both cancer cells compared to aca and bala. Due to the more potent activity shown by 7-aca, A2780 and ZR-75-1 cells treated with 7-aca was chosen for metabolite analysis of cell lysates and aca was used as comparison. Several biomarker metabolites were decreased significantly (P<0.05) by the compounds, including ATP and NAD+ in the oxidative phosphorylation (OXPHOS) pathway and glucose-6-phosphate dehydrogenase, glutathione disulphide and NADPH in the pentose phosphate pathway (PPP). 7-Acashowed to cause greater reduction in all these metabolites compared to aca. These findings showed promising results for the compounds to be used as anti-cancer agents.;3) Anti-inflammatory assessment of 7-aca, aca and bala demonstrated the ability of these compounds to inhibit production of the pro-inflammatory cytokines TNF-α, IL1β and IL-6 by LPS-stimulated THP-1 macrophage cells. Bala at 10µM showed the strongest inhibition of TNF-α, IL-1β and IL-6 by 75%, 68% and 67%, respectively. 7-aca and aca showed similar activity by causing approximately 40-50% inhibition of all the cytokines. Due to the potent activity shown by bala, this compound was selected to carry out a retrospective investigation into any gene changes. RNA-sequencing analysis on RNA isolated from THP-1 macrophage cells treated with LPS or combination treatment of LPS and bala (LPS/bala) revealed that 27 genes associated with the cytokine-cytokine interaction pathway including TNF-α and IL-6 were downregulated by LPS/Bala treatment compared to LPS treatment alone. Furthermore, another two significant (P<0.05) pathways were also affected; the TNF-α and JAKSTAT signalling pathways. The genes associated with these pathways were shown to be significantly (P<0.05) down-regulated by LPS/bala treatment compared to LPS treatment alone. 4) 7-aca, aca and bala significantly (P<0.01) protected SH-SY5Y cells(neuroblastoma) from ROS generated by tert-butyl hydroperoxide (TBPH). Furthermore, these compounds showed their protective effects from TBPH-induced toxicity/oxidative stress through an increase in ΔΨM and decrease in caspase 3/7 levels in SH-SY5Y cells. Glutathione (GSH) levels were significantly (P<0.01) increased by all compounds which confirmed their potential antioxidant activity.;Bala showed to be the most potent antioxidant by increasing GSH level by 66.1%, decrease ROS level by 69% and inhibiting DPPH radical (IC50 = 6.2 µM). 7-Aca and aca showed similar antioxidant activity and neuroprotective effect. These findings suggest that compounds from A. malaccensis and H. dryobalanoides can provide excellent sources of natural raw material to isolate bioactive agents. In addition, the data also showed that the compounds isolated could possibly be used as anti-cancer, anti-inflammatory and neuroprotective agents in the future, based on the positive results obtained from the in vitro assays in this study.Natural products have been used for medicinal purposes for centuries and remain the main source of new drugs to treat diseases due to their biological activities such as anticancer, anti-inflammatory and neuroprotective effects. This thesis aimed to : 1) isolate bioactive compounds from two Malaysian plants which are: Aquilaria malaccensis and Hopea dryobalanoides using column chromatography and characterised them by nuclear magnetic resonance (NMR); 2) assess the anti-cancer activity of the isolated compounds through various in vitro assays and metabolomics profiling; 3) investigate the anti-inflammatory properties of the compounds by inhibition of the pro-inflammatory cytokines (tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6)) levels in response to lipopolysaccharide (LPS) stimulation in macrophage cells and identify the effects of the compound treatments on the gene expression against the inflammatory response caused by LPS-stimulated macrophage cells; 4) examine the protective effects of the compounds against oxidative stress induced in neuron cells.1) Plants extracts, investigated phytochemically, resulted in the isolation of 7-methoxyacacetin (7-aca) from the hexane extract of A. malaccensis twigs for the first time, a mixture of two compounds quercitrin and afzelin (Q/A) from the methanol extract of A. malaccensis twigs and two compounds named balanocarpol (bala) and heimiol A from the ethyl acetate extract of H. dryobalanoides bark. There are limited reports on the biological activity of 7-aca, however a similar compound called acacetin (aca) has been reported to have a range of bioactivates including anti-cancer, anti-inflammatory and protective effects. Therefore, aca was purchased commercially for comparison purposes.;2) Cytotoxicity screening of 7-aca, aca, Q/A and bala resulted in decreased viability of A2780 (ovarian) and ZR-75-1 (breast) cells in a concentration dependant manner. 7-Aca exhibited a more potent cytotoxicity against A2780 and ZR-75-1 cells (IC50=7.9µM and 8.5µM, respectively) compared to aca (IC50= 19.5µM and 17.5µM,respectively). Heimiol A did not show toxic effects against both cancer cells even at the highest concentration (150µM). All compounds showed selective toxicity toward the cancers cells, as they did not cause toxicity against normal PNT2A (prostate) cells. Further investigation behind the cytotoxic effect of the compounds revealed that 7-aca,aca, Q/A and bala caused the production of ROS, depletion of mitochondria membrane potential (ΔΨM) and an increase in caspase-3/7 levels in A2780 and ZR-75-1 cells. Many studies have reported that an excessive increase in ROS in cancer cells disrupts the mitochondrial membrane thus causing the loss of ΔΨM that leads to activation of effectors such as caspase-3, which eventually result in apoptotic cell death. Moreover,7-aca showed the strongest anti-metastatic effects through the inhibition of adhesion of cancer cells to the ECM protein fibronectin as well as inhibiting the migration and invasion of A2780 and ZR-75-1 cells by approximately 50-70%. The overall results revealed that 7-aca showed a stronger anti-cancer effects towards both cancer cells compared to aca and bala. Due to the more potent activity shown by 7-aca, A2780 and ZR-75-1 cells treated with 7-aca was chosen for metabolite analysis of cell lysates and aca was used as comparison. Several biomarker metabolites were decreased significantly (P<0.05) by the compounds, including ATP and NAD+ in the oxidative phosphorylation (OXPHOS) pathway and glucose-6-phosphate dehydrogenase, glutathione disulphide and NADPH in the pentose phosphate pathway (PPP). 7-Acashowed to cause greater reduction in all these metabolites compared to aca. These findings showed promising results for the compounds to be used as anti-cancer agents.;3) Anti-inflammatory assessment of 7-aca, aca and bala demonstrated the ability of these compounds to inhibit production of the pro-inflammatory cytokines TNF-α, IL1β and IL-6 by LPS-stimulated THP-1 macrophage cells. Bala at 10µM showed the strongest inhibition of TNF-α, IL-1β and IL-6 by 75%, 68% and 67%, respectively. 7-aca and aca showed similar activity by causing approximately 40-50% inhibition of all the cytokines. Due to the potent activity shown by bala, this compound was selected to carry out a retrospective investigation into any gene changes. RNA-sequencing analysis on RNA isolated from THP-1 macrophage cells treated with LPS or combination treatment of LPS and bala (LPS/bala) revealed that 27 genes associated with the cytokine-cytokine interaction pathway including TNF-α and IL-6 were downregulated by LPS/Bala treatment compared to LPS treatment alone. Furthermore, another two significant (P<0.05) pathways were also affected; the TNF-α and JAKSTAT signalling pathways. The genes associated with these pathways were shown to be significantly (P<0.05) down-regulated by LPS/bala treatment compared to LPS treatment alone. 4) 7-aca, aca and bala significantly (P<0.01) protected SH-SY5Y cells(neuroblastoma) from ROS generated by tert-butyl hydroperoxide (TBPH). Furthermore, these compounds showed their protective effects from TBPH-induced toxicity/oxidative stress through an increase in ΔΨM and decrease in caspase 3/7 levels in SH-SY5Y cells. Glutathione (GSH) levels were significantly (P<0.01) increased by all compounds which confirmed their potential antioxidant activity.;Bala showed to be the most potent antioxidant by increasing GSH level by 66.1%, decrease ROS level by 69% and inhibiting DPPH radical (IC50 = 6.2 µM). 7-Aca and aca showed similar antioxidant activity and neuroprotective effect. These findings suggest that compounds from A. malaccensis and H. dryobalanoides can provide excellent sources of natural raw material to isolate bioactive agents. In addition, the data also showed that the compounds isolated could possibly be used as anti-cancer, anti-inflammatory and neuroprotective agents in the future, based on the positive results obtained from the in vitro assays in this study
Social innovation systems for building resilient communities
Get PDFA global investigation into social innovation systems for building resilient communities, this doctoral thesis introduces a hypothesis that social innovation in the built environment occurs over phases of network, framework and architecture. The literature review links social innovation to sustainability and resilience science, and looks at the emergence of social innovation in response to social, economic and environmental challenges. Case studies and ethnographic methods are used to probe the barriers and enablers of social innovation in each of the above phases. The case studies were selected as examples of networked approaches to urban design. Tools that enable participation in planning are examined, alongside more bottom up tactics that promote community self-management of common resources.;The final phase of research looks at housing in particular as a way to promote inclusive growth and spatial equality for communities, facing the effects of neoliberal policy and planning. The study represents a new approach to research in architecture that takes an international perspective in the analysis of phenomena such as transdisciplinarity, insurgent activism and politics in space. Findings suggest that new narratives - platforms and spaces - in architecture are required to support open decision-making and the creation of public value in communities. Above all, this means leaning on new knowledge from diverse disciplines such as anthropology, system sciences and technology to further a deeper understanding of the dynamics that allow social innovation to thrive in an ecology for cities.A global investigation into social innovation systems for building resilient communities, this doctoral thesis introduces a hypothesis that social innovation in the built environment occurs over phases of network, framework and architecture. The literature review links social innovation to sustainability and resilience science, and looks at the emergence of social innovation in response to social, economic and environmental challenges. Case studies and ethnographic methods are used to probe the barriers and enablers of social innovation in each of the above phases. The case studies were selected as examples of networked approaches to urban design. Tools that enable participation in planning are examined, alongside more bottom up tactics that promote community self-management of common resources.;The final phase of research looks at housing in particular as a way to promote inclusive growth and spatial equality for communities, facing the effects of neoliberal policy and planning. The study represents a new approach to research in architecture that takes an international perspective in the analysis of phenomena such as transdisciplinarity, insurgent activism and politics in space. Findings suggest that new narratives - platforms and spaces - in architecture are required to support open decision-making and the creation of public value in communities. Above all, this means leaning on new knowledge from diverse disciplines such as anthropology, system sciences and technology to further a deeper understanding of the dynamics that allow social innovation to thrive in an ecology for cities
The spontaneous symmetry breaking of light in passive Kerr ring resonators
Get PDFKerr ring resonators, where laser light circulates and interacts with a non linear medium, have a vast range of applications, especially in the field of metrology and telecommunications. An important feature that can occur in Kerr ring resonator set ups with two field components is a spontaneous symmetry breaking (SSB) of the intensities of the circulating fields. At low input powers, the two components circulate in the resonator with the same intensity, but this symmetry may spontaneously break upon a minute change of input conditions resulting in one component becoming dominant while the other is suppressed. This thesis concerns the study of this symmetry breaking phenomenon and the features that can be exploited in wide-reaching applications in photonics and quantum technologies. In early chapters we provide an introduction to passive Kerr ring resonators both in terms of the theoretical and experimental setups, and to the established model used to describe a single light beam circulating in a Kerr ring resonator, the Lugiato-Lefever equation (LLE). Systems of coupled LLEs are then used to model multiple modes circulating simultaneously in the resonator. We proceed to describe SSB in the intensities of these modes upon changes of experimentally controllable parameters. Through a linear stability analysis of the system of coupled equations we investigate the possible dynamical regimes starting from useful field oscillations and leading to the novel behaviour of periodic switching between the dominant and suppressed field components. Later to describe a wide range of experimental setups, this analysis is generalised to arbitrary self- and cross-phase modulation strengths. In subsequent chapters we describe our studies into how Temporal Cavity Solitons (TCS) evolve within the coupled LLE system. TCS have themselves a wide range of applications in the generation of, for example, optical frequency combs. It is shown for the first time and with external experimental verification, that TCS may also experience SSB in Kerr ring resonators with orthogonal polarization modes, a result which may lead to novel telecommunications applications. These symmetry broken TCS can, under certain conditions, begin to ‘breath’ in simple and complex manners and even show the periodic switching of the dominant and suppressed components previously mentioned only now in self-localised pulses instead of continuous waves. The final chapter of this thesis describes significant advances in two projects which lay the ground for further study. The first section builds on the balancing of asymmetric input conditions in a manner that restores a connected perturbed pitchfork bifurcation. This is important for applications looking to utilise interchangeable suppressed and dominant field roles in systems with physical imperfections. In the second we outline the derivation and early simulations of a new model which expands to four field components. It is shown how the enlarged degrees of freedom leads to ‘nested’ symmetry breaking bifurcations, opening new avenues for applications requiring more diversity and flexibility than just two coupled components.Kerr ring resonators, where laser light circulates and interacts with a non linear medium, have a vast range of applications, especially in the field of metrology and telecommunications. An important feature that can occur in Kerr ring resonator set ups with two field components is a spontaneous symmetry breaking (SSB) of the intensities of the circulating fields. At low input powers, the two components circulate in the resonator with the same intensity, but this symmetry may spontaneously break upon a minute change of input conditions resulting in one component becoming dominant while the other is suppressed. This thesis concerns the study of this symmetry breaking phenomenon and the features that can be exploited in wide-reaching applications in photonics and quantum technologies. In early chapters we provide an introduction to passive Kerr ring resonators both in terms of the theoretical and experimental setups, and to the established model used to describe a single light beam circulating in a Kerr ring resonator, the Lugiato-Lefever equation (LLE). Systems of coupled LLEs are then used to model multiple modes circulating simultaneously in the resonator. We proceed to describe SSB in the intensities of these modes upon changes of experimentally controllable parameters. Through a linear stability analysis of the system of coupled equations we investigate the possible dynamical regimes starting from useful field oscillations and leading to the novel behaviour of periodic switching between the dominant and suppressed field components. Later to describe a wide range of experimental setups, this analysis is generalised to arbitrary self- and cross-phase modulation strengths. In subsequent chapters we describe our studies into how Temporal Cavity Solitons (TCS) evolve within the coupled LLE system. TCS have themselves a wide range of applications in the generation of, for example, optical frequency combs. It is shown for the first time and with external experimental verification, that TCS may also experience SSB in Kerr ring resonators with orthogonal polarization modes, a result which may lead to novel telecommunications applications. These symmetry broken TCS can, under certain conditions, begin to ‘breath’ in simple and complex manners and even show the periodic switching of the dominant and suppressed components previously mentioned only now in self-localised pulses instead of continuous waves. The final chapter of this thesis describes significant advances in two projects which lay the ground for further study. The first section builds on the balancing of asymmetric input conditions in a manner that restores a connected perturbed pitchfork bifurcation. This is important for applications looking to utilise interchangeable suppressed and dominant field roles in systems with physical imperfections. In the second we outline the derivation and early simulations of a new model which expands to four field components. It is shown how the enlarged degrees of freedom leads to ‘nested’ symmetry breaking bifurcations, opening new avenues for applications requiring more diversity and flexibility than just two coupled components
Power and the historic abuse of children in care
Get PDFThis thesis advances understandings of the historic abuse of children in care through an exploration of power and also offers new insights in relation to conceptualising power within the field of social work. Drawing on interviews with victims/survivors of historic abuse from Scotland, this thesis will argue that understanding power within the context of historic abuse is central to advancing both social policy and social work practice in this area. Furthermore, despite the existence of a plethora of knowledge on the topic of power, an exploration of power specifically in relation to the historic abuse of children in care, allows for theoretical advancements in conceptualising and understanding power within the social work context.;Through an analysis of the data derived from interviews with victims/survivors of historic abuse, three key findings are presented. Firstly, it is evidenced that power in relation to the historic abuse of children in care is exercised on three interrelated yet distinct levels, namely that of the individual, professional and structural. Whilst secondly, it is shown that the exercise of such power may impact individuals in limiting, productive and simultaneously limiting/productive ways. And thirdly, it is argued that the prevailing dichotomy which features so centrally in theoretical conceptualisations of power within social work as something 'good or bad', 'positive or negative' and 'productive or limiting' is essentially false, and that power also needs to be recognised as something which may impact in a dualistic way; and therefore a new framework for "Power Informed Practice" is offered. As a result of these findings, it is imperative that those concerned with the historic abuse of children in care, are mindful of the workings of power in how practice and policy responses are shaped.This thesis advances understandings of the historic abuse of children in care through an exploration of power and also offers new insights in relation to conceptualising power within the field of social work. Drawing on interviews with victims/survivors of historic abuse from Scotland, this thesis will argue that understanding power within the context of historic abuse is central to advancing both social policy and social work practice in this area. Furthermore, despite the existence of a plethora of knowledge on the topic of power, an exploration of power specifically in relation to the historic abuse of children in care, allows for theoretical advancements in conceptualising and understanding power within the social work context.;Through an analysis of the data derived from interviews with victims/survivors of historic abuse, three key findings are presented. Firstly, it is evidenced that power in relation to the historic abuse of children in care is exercised on three interrelated yet distinct levels, namely that of the individual, professional and structural. Whilst secondly, it is shown that the exercise of such power may impact individuals in limiting, productive and simultaneously limiting/productive ways. And thirdly, it is argued that the prevailing dichotomy which features so centrally in theoretical conceptualisations of power within social work as something 'good or bad', 'positive or negative' and 'productive or limiting' is essentially false, and that power also needs to be recognised as something which may impact in a dualistic way; and therefore a new framework for "Power Informed Practice" is offered. As a result of these findings, it is imperative that those concerned with the historic abuse of children in care, are mindful of the workings of power in how practice and policy responses are shaped
Study on structural integrity of welded components using the LMM
Get PDFIndustries, which have structures, subjected to high temperatures, such as the nuclear power plant industry, give paramount importance to structural integrity assessments due to the obvious catastrophic effect an unfortunate failure might cause. The presence of welds increases the susceptibility of premature failure within the structures. Hence identifying the structural response of welded components under cyclic loading conditions and developing methods to predict their safe life is of significant importance. The work within this thesis focuses on the investigation of cyclic plasticity and creep-cyclic plasticity interaction of welded components, and the consequential damage assessment using the Linear Matching Method (LMM). Firstly, a numerical investigation and parametric study on the cyclic plasticity behaviour of a butt-welded pipe under cyclic thermal and constant pressure load is undertaken. The most critical results are used to create limit load envelopes that may be used to design welded pipes within the specified range.;Secondly, through a series of case studies, the effect of various complex loading conditions on the evolution and progress of fatigue damage, creep damage and creep-fatigue interaction of welded connectors, commonly found in power plants, are identified and discussed comprehensively using the Direct Steady Cycle Analysis (DSCA) and the extended Direct Steady Cycle Analysis(eDSCA) method within the Linear Matching Method Framework (LMMF). Finally, the subroutine is enhanced to account for any previous residual stress such as the welding residual stress (WRS) on the shakedown-ratchet limit interaction curves and the creep-fatigue endurance. With a welded flange case study, the effect of WRS on mean strain during the transient cycles and the fatigue damage at steady state is demonstrated.Industries, which have structures, subjected to high temperatures, such as the nuclear power plant industry, give paramount importance to structural integrity assessments due to the obvious catastrophic effect an unfortunate failure might cause. The presence of welds increases the susceptibility of premature failure within the structures. Hence identifying the structural response of welded components under cyclic loading conditions and developing methods to predict their safe life is of significant importance. The work within this thesis focuses on the investigation of cyclic plasticity and creep-cyclic plasticity interaction of welded components, and the consequential damage assessment using the Linear Matching Method (LMM). Firstly, a numerical investigation and parametric study on the cyclic plasticity behaviour of a butt-welded pipe under cyclic thermal and constant pressure load is undertaken. The most critical results are used to create limit load envelopes that may be used to design welded pipes within the specified range.;Secondly, through a series of case studies, the effect of various complex loading conditions on the evolution and progress of fatigue damage, creep damage and creep-fatigue interaction of welded connectors, commonly found in power plants, are identified and discussed comprehensively using the Direct Steady Cycle Analysis (DSCA) and the extended Direct Steady Cycle Analysis(eDSCA) method within the Linear Matching Method Framework (LMMF). Finally, the subroutine is enhanced to account for any previous residual stress such as the welding residual stress (WRS) on the shakedown-ratchet limit interaction curves and the creep-fatigue endurance. With a welded flange case study, the effect of WRS on mean strain during the transient cycles and the fatigue damage at steady state is demonstrated
Minimisation of energy costs considering electric vehicle for a smart home system
Get PDFSmart residential home systems have good potential for more efficient use of energy, reduced cost and less effects to environment. In order to adapt to new technologies such as electric vehicles (EVs), photovoltaic (PV) system, photovoltaic-thermal (PV-T) system, and solar water heater (SWH) system, novel demand side management (DSM) methods are required to effectively control EV and renewable technologies for residential energy systems. More importantly, customers play a key role in DSM as they have the energy usage choices according to their preferences. To understand the benefits for residential EV end users, their usage behaviours, such as driving behaviour, charging and discharging periods, willingness to participate to vehicle to grid (V2G), need to be considered in the DSM.;In this thesis work, a novel DSM model framework is developed for a residential home system, considering EV, energy storage system (ESS), renewable technologies, and human behaviours. Survey data are collected and analysed to support the model development. Based on model, minimisation of the energy costs of residential home systems is explored by controlling the charging/discharging status of EV and a separate ESS under practical constraints. Key factors such as the degradation cost of EV and ESS batteries, user's driving behaviour, and different types of electricity tariffs are included in the optimisation. Extensive case studies have been undertaken to investigate the operation strategies under various scenarios. The options and potential benefits of V2G are discussed.;To further investigate the DSM for residential homes with the use of renewable energy, two solar water heating systems, the hybrid PV-T and the PV-SWH, are considered into the energy cost evaluation. Models for both PV-T and PV-SWH are formulated and added into the modelling framework for residential home systems. Built on the work of optimal charging/discharging of EV and ESS, the optimal switch operations of the PV-SWH system have been calculated, through which further cost reduction can be achieved. For the option of PV-SWH with limited solar panel space, the split of areas between PV and SWH is determined through a pseudo-optimisation route. Numerical studies have been conducted to examine the economic benefits of solar thermal collectors, the comparisons between PV-T and PV-SWH, and the effective use of the limited solar panel area for PV-SWH.;Finally, different appraisal methods are applied to analyse the investment worth of the residential energy household systems with optimal DSM. The most beneficial investment solutions are obtained from the relevant case studies.;Through the above systematic investigation of DSM for smart home energy systems, improved understanding on how to reduce energy cost for end users are obtained, including new insights on the benefits and conditions of V2G for EV users. The established modelling framework can easily include sub energy systems, e.g. EV, ESS, and renewable energy systems. Complex variation factors such as EV driving behaviour, external environment temperature, solar radiation, electricity tariffs are considered to achieve optimal operation strategies to reduce energy cost at residential home level. Financial analysis is applied to analyse the investment worth of these residential energy household systems. The optimal system choices for the end user are discussed through case studies.Smart residential home systems have good potential for more efficient use of energy, reduced cost and less effects to environment. In order to adapt to new technologies such as electric vehicles (EVs), photovoltaic (PV) system, photovoltaic-thermal (PV-T) system, and solar water heater (SWH) system, novel demand side management (DSM) methods are required to effectively control EV and renewable technologies for residential energy systems. More importantly, customers play a key role in DSM as they have the energy usage choices according to their preferences. To understand the benefits for residential EV end users, their usage behaviours, such as driving behaviour, charging and discharging periods, willingness to participate to vehicle to grid (V2G), need to be considered in the DSM.;In this thesis work, a novel DSM model framework is developed for a residential home system, considering EV, energy storage system (ESS), renewable technologies, and human behaviours. Survey data are collected and analysed to support the model development. Based on model, minimisation of the energy costs of residential home systems is explored by controlling the charging/discharging status of EV and a separate ESS under practical constraints. Key factors such as the degradation cost of EV and ESS batteries, user's driving behaviour, and different types of electricity tariffs are included in the optimisation. Extensive case studies have been undertaken to investigate the operation strategies under various scenarios. The options and potential benefits of V2G are discussed.;To further investigate the DSM for residential homes with the use of renewable energy, two solar water heating systems, the hybrid PV-T and the PV-SWH, are considered into the energy cost evaluation. Models for both PV-T and PV-SWH are formulated and added into the modelling framework for residential home systems. Built on the work of optimal charging/discharging of EV and ESS, the optimal switch operations of the PV-SWH system have been calculated, through which further cost reduction can be achieved. For the option of PV-SWH with limited solar panel space, the split of areas between PV and SWH is determined through a pseudo-optimisation route. Numerical studies have been conducted to examine the economic benefits of solar thermal collectors, the comparisons between PV-T and PV-SWH, and the effective use of the limited solar panel area for PV-SWH.;Finally, different appraisal methods are applied to analyse the investment worth of the residential energy household systems with optimal DSM. The most beneficial investment solutions are obtained from the relevant case studies.;Through the above systematic investigation of DSM for smart home energy systems, improved understanding on how to reduce energy cost for end users are obtained, including new insights on the benefits and conditions of V2G for EV users. The established modelling framework can easily include sub energy systems, e.g. EV, ESS, and renewable energy systems. Complex variation factors such as EV driving behaviour, external environment temperature, solar radiation, electricity tariffs are considered to achieve optimal operation strategies to reduce energy cost at residential home level. Financial analysis is applied to analyse the investment worth of these residential energy household systems. The optimal system choices for the end user are discussed through case studies
Freezing in kinetic ferromagnets
Get PDFIn this thesis I present studies of the non-equilibrium dynamics of Ising and Potts ferromagnets in two spatial dimensions. While the conception of these models was originally motivated by a desire to understand the phenomena surrounding equilibrium phase transitions, they have found considerable use in non-equilibrium Statistical Physics. Despite being well studied, even from a non-equilibrium viewpoint, a number of surprisingly basic and fundamental gaps in our understanding of Ising and Potts models have come to light in recent decades. For example, the tacit assumption that Ising ferromagnets should always reach their ground state at zero-temperature has been found incorrect, and unexpected features of the associated relaxation process have come to light. With the Potts model the situation is stranger still: the late time final states that persist in two dimensions are considerably richer than those of the Ising model, and the relaxation times are complex and not yet well understood. In this thesis I examine basic aspects of zero-temperature coarsening in two dimensional Ising and Potts ferromagnets. I explore the timescales associated with zero-temperature freezing in the Ising model, and uncover the existence of an overlooked relaxation timescale. I then investigate the final states of the zero-temperature Potts model on the triangular lattice, which prior to this work had not been examined. I continue my studies of the Potts model to situations of increased ground state degeneracy and extended local interaction rules.In this thesis I present studies of the non-equilibrium dynamics of Ising and Potts ferromagnets in two spatial dimensions. While the conception of these models was originally motivated by a desire to understand the phenomena surrounding equilibrium phase transitions, they have found considerable use in non-equilibrium Statistical Physics. Despite being well studied, even from a non-equilibrium viewpoint, a number of surprisingly basic and fundamental gaps in our understanding of Ising and Potts models have come to light in recent decades. For example, the tacit assumption that Ising ferromagnets should always reach their ground state at zero-temperature has been found incorrect, and unexpected features of the associated relaxation process have come to light. With the Potts model the situation is stranger still: the late time final states that persist in two dimensions are considerably richer than those of the Ising model, and the relaxation times are complex and not yet well understood. In this thesis I examine basic aspects of zero-temperature coarsening in two dimensional Ising and Potts ferromagnets. I explore the timescales associated with zero-temperature freezing in the Ising model, and uncover the existence of an overlooked relaxation timescale. I then investigate the final states of the zero-temperature Potts model on the triangular lattice, which prior to this work had not been examined. I continue my studies of the Potts model to situations of increased ground state degeneracy and extended local interaction rules
Keeping the car clean, on the electrification of private transport
No full textThe electrification of private road vehicles - and the provision of a low carbon generation mix that supplies the energy for their motion - is likely to be a key contributor to meeting net zero targets and limiting the disastrous effects of anthropogenic climate change.The work presented in this thesis surrounds two aspects of this transition. Firstly,as EVs are fundamentally different to internal combustion vehicles (ICVs), in that their energy storage capacity is far smaller and the rate at which it can be replenished is much slower, there has been consumer resistance to their adoption due to the perception that their charging carries inconvenience compared to ICV fuelling. Secondly, as the energy demand of private road vehicles is shifted from the petrochemical supply chain to the electricity grid, there are potential i) issues surrounding the resilience of the grid and ii) opportunities resulting from the flexibility and 'schedulability' of EV charging in enabling the further decarbonisation of the power sector.With regards to the first aspect, this thesis presents an investigation of the inconvenience of EV charging versus ICV fuelling and how this is likely to change depending on vehicle parameters - battery capacity and charger power - and the set of locations at which it can be charged. It was found that if the EV can be charged while parked at home, the majority (80-95%) of individuals could make the transition to EVs without suffering any increase in time penalty associated with charging compared to ICV fuelling with modest battery capacities at the lower end of the market. However, for drivers who cannot charge at home this convenience parity is harder to achieve.This can be made easier by increasing battery capacity and charger power and ensuring the provision of public destination and en route charging infrastructure. This thesis presents characterisation of the likely demand at such infrastructure based on the analysis of smartphone app users' locational data. It was found that this kind of EV charging demand is likely to vary significantly in time and by location, depending on what kind of public amenity it is installed at; such an approach could be invaluable to transport and power system planners given the projected rapid uptake of EVs. This thesis presents analysis into the likely impact of EV charging on residential distribution networks, taking into account the effect of i) the way in which drivers schedule charge events, ii) the social demographics (and hence travel habits) of the individuals served by a network and iii) the effect of the rapidly evolving EV sector and the resulting changes in technical parameters and level of charging infrastructure. By means of case studies on real distribution networks in Glasgow's South side, it was found that all three of the above factors have a significant effect on the impact seen from EV charging and that, if their charging is uncontrolled, residential distribution networks in better-off areas with high rates of car ownership are unlikely to be able to cope with charging load when over 40% of vehicles are replaced with EVs. Based on the above finding, this thesis presents an investigation of the potential of EVs to interact positively with the grid, by charging selectively to i) avoid network peaks and thus enable a higher penetration of EVs before the network must be reinforced and ii) enable the further decarbonisation of the power system by charging when grid carbon emissions are low and local renewable energy is in surplus. Techniques to schedule charge events are presented: a 'valley filling' optimisation approach based on the controller having perfect foresight of the arrival of vehicles to represent the best case; and a set of low-information heuristics that could operate using data from 'smart' EV chargers.Though some of the heuristics could perform similarly to the formal optimisation, both methods resulted in the network being operated outwith statutory GB voltage limits for 100% penetration of EVs. Finally, it was found that there is significant potential for EVs to complement the decarbonisation of the power system. If 'smart charged',their resulting carbon intensity (gCO2/km) can be reduced to around a fifth of that of a new petrol or diesel car if charged from the current GB grid. Furthermore, a penetration of 20% EVs in Scotland could be smart-charged to absorb up to 75% of curtailed generation at Scotland's largest onshore wind farm.The electrification of private road vehicles - and the provision of a low carbon generation mix that supplies the energy for their motion - is likely to be a key contributor to meeting net zero targets and limiting the disastrous effects of anthropogenic climate change.The work presented in this thesis surrounds two aspects of this transition. Firstly,as EVs are fundamentally different to internal combustion vehicles (ICVs), in that their energy storage capacity is far smaller and the rate at which it can be replenished is much slower, there has been consumer resistance to their adoption due to the perception that their charging carries inconvenience compared to ICV fuelling. Secondly, as the energy demand of private road vehicles is shifted from the petrochemical supply chain to the electricity grid, there are potential i) issues surrounding the resilience of the grid and ii) opportunities resulting from the flexibility and 'schedulability' of EV charging in enabling the further decarbonisation of the power sector.With regards to the first aspect, this thesis presents an investigation of the inconvenience of EV charging versus ICV fuelling and how this is likely to change depending on vehicle parameters - battery capacity and charger power - and the set of locations at which it can be charged. It was found that if the EV can be charged while parked at home, the majority (80-95%) of individuals could make the transition to EVs without suffering any increase in time penalty associated with charging compared to ICV fuelling with modest battery capacities at the lower end of the market. However, for drivers who cannot charge at home this convenience parity is harder to achieve.This can be made easier by increasing battery capacity and charger power and ensuring the provision of public destination and en route charging infrastructure. This thesis presents characterisation of the likely demand at such infrastructure based on the analysis of smartphone app users' locational data. It was found that this kind of EV charging demand is likely to vary significantly in time and by location, depending on what kind of public amenity it is installed at; such an approach could be invaluable to transport and power system planners given the projected rapid uptake of EVs. This thesis presents analysis into the likely impact of EV charging on residential distribution networks, taking into account the effect of i) the way in which drivers schedule charge events, ii) the social demographics (and hence travel habits) of the individuals served by a network and iii) the effect of the rapidly evolving EV sector and the resulting changes in technical parameters and level of charging infrastructure. By means of case studies on real distribution networks in Glasgow's South side, it was found that all three of the above factors have a significant effect on the impact seen from EV charging and that, if their charging is uncontrolled, residential distribution networks in better-off areas with high rates of car ownership are unlikely to be able to cope with charging load when over 40% of vehicles are replaced with EVs. Based on the above finding, this thesis presents an investigation of the potential of EVs to interact positively with the grid, by charging selectively to i) avoid network peaks and thus enable a higher penetration of EVs before the network must be reinforced and ii) enable the further decarbonisation of the power system by charging when grid carbon emissions are low and local renewable energy is in surplus. Techniques to schedule charge events are presented: a 'valley filling' optimisation approach based on the controller having perfect foresight of the arrival of vehicles to represent the best case; and a set of low-information heuristics that could operate using data from 'smart' EV chargers.Though some of the heuristics could perform similarly to the formal optimisation, both methods resulted in the network being operated outwith statutory GB voltage limits for 100% penetration of EVs. Finally, it was found that there is significant potential for EVs to complement the decarbonisation of the power system. If 'smart charged',their resulting carbon intensity (gCO2/km) can be reduced to around a fifth of that of a new petrol or diesel car if charged from the current GB grid. Furthermore, a penetration of 20% EVs in Scotland could be smart-charged to absorb up to 75% of curtailed generation at Scotland's largest onshore wind farm
Machine learning approaches to support life extension of nuclear power reaction
Get PDFCondition monitoring is the process of observing a parameter, or multiple parameters, extracted from industrial assets which provide an indication of their overall health or presence of faults. In many instances the data produced is numerous, difficult to understand and time consuming to analyse. In the nuclear power industry large volumes of data are captured through inspections and monitoring but only a relatively small amount of the data has associated health information. Machine learning has been identified as a solution to these issues allowing data to be analysed quicker and in greater volumes, alleviating some of the demands on the relevant engineers. Within this thesis two key contributions are made. The first is the development of a model of fuel channel bore estimation and subsequent deployment to make estimations of operational data. Fuel Grab Load Trace (FGLT) data is operational data which was never intended to be used in condition monitoring. Greater understanding of FGLT data was obtained by targeted analysis of specific regions of the data based on physical understanding of nuclear assets. The model was produced by combining techniques from machine learning supplemented with formalised engineering knowledge to provide decision support in a safety-related environment. The model was found to produce estimations of fuel bore within 1mm root mean square error on real historical FGLT data. The second is the exploration and implementation of semi-supervised machine learning techniques applied to the detection of cracks within nuclear reactor monitoring data. Semi-supervised machine learning is attractive as it provides comparable results to supervised machine learning techniques without the costly burden of labelling large volumes of data, a commonly occurring challenge in nuclear reactor core condition monitoring. Three different semi-supervised machine learning approaches have been evaluated and for the detection of cracks using FGLT data it has been found that Transductive Support Vector Machines have the best performance. In this thesis I demonstrate the benefits of machine learning and semi-supervised machine learning to decision support of nuclear reactors through two health monitoring related problems of nuclear reactor cores. Challenges still remain with the application of machine learning in the nuclear condition monitoring domain including the high cost of obtaining labelled data, lack of historical operate to failure data and incorporating future data in the training of algorithms as it is made available.Condition monitoring is the process of observing a parameter, or multiple parameters, extracted from industrial assets which provide an indication of their overall health or presence of faults. In many instances the data produced is numerous, difficult to understand and time consuming to analyse. In the nuclear power industry large volumes of data are captured through inspections and monitoring but only a relatively small amount of the data has associated health information. Machine learning has been identified as a solution to these issues allowing data to be analysed quicker and in greater volumes, alleviating some of the demands on the relevant engineers. Within this thesis two key contributions are made. The first is the development of a model of fuel channel bore estimation and subsequent deployment to make estimations of operational data. Fuel Grab Load Trace (FGLT) data is operational data which was never intended to be used in condition monitoring. Greater understanding of FGLT data was obtained by targeted analysis of specific regions of the data based on physical understanding of nuclear assets. The model was produced by combining techniques from machine learning supplemented with formalised engineering knowledge to provide decision support in a safety-related environment. The model was found to produce estimations of fuel bore within 1mm root mean square error on real historical FGLT data. The second is the exploration and implementation of semi-supervised machine learning techniques applied to the detection of cracks within nuclear reactor monitoring data. Semi-supervised machine learning is attractive as it provides comparable results to supervised machine learning techniques without the costly burden of labelling large volumes of data, a commonly occurring challenge in nuclear reactor core condition monitoring. Three different semi-supervised machine learning approaches have been evaluated and for the detection of cracks using FGLT data it has been found that Transductive Support Vector Machines have the best performance. In this thesis I demonstrate the benefits of machine learning and semi-supervised machine learning to decision support of nuclear reactors through two health monitoring related problems of nuclear reactor cores. Challenges still remain with the application of machine learning in the nuclear condition monitoring domain including the high cost of obtaining labelled data, lack of historical operate to failure data and incorporating future data in the training of algorithms as it is made available
The perceptions and experiences of midcareer professionals (aged 45 years and over) who are masters level part-time students participating in health and nursing programmes at a higher education institution in Scotland
Get PDFThis thesis explores the perceptions and experiences of midcareer (aged 45 years and over) nurses and midwives attending a particular Higher Educational Institute (HEI) in Scotland to participate in part-time Health and Nursing programmes at master's level. Midcareer nurses are the largest group of currently registered nurses (NMC, 2019) and the number of midcareer nurses and midwives participating in master's level study is increasing. Despite this, very few research studies have been conducted looking at their views.;The aim of this descriptive phenomenological study was to bring to the fore the perceptions that midcareer nurses have about participating in master's programmes as older students in order to identify actions that can be taken forward to add to debates about the participation of midcareer professionals in higher education. Twelve midcareer nurses were interviewed, in depth, about their experiences.;Utilising Braun and Clarke's (2006, 2013b) framework for thematic analysis an overarching theme, 'Becoming a Confident Contributor' emerged. Participants revealed that they aspired to be 'confident contributors', valued for the knowledge and skills they brought to their teams, making efforts to improve themselves, others and their workplaces. Confident contributors also work towards creating a positive legacy as their careers advanced. Two subthemes 'Seeking recognition as a skilled practitioner' and 'The price of recognition' revealed the personal, social and cultural factors that impacted upon participants experiences. They discussed the factors that contributed to their recognition and boosted their self-esteem. This was not however without personal cost both inside and outside their workplaces. Participants also discussed their supports, the contribution of the HEI and the particular character required to succeed.;Viewing participants' experiences as a struggle for recognition (Honneth, 1994, 1995) provided the richest insight. However, it was not the only theoretical lens that helped to provide an understanding of the participants' involvement with the process of gaining a master's. Incentive theories suggest that midcareer nurses may have more altruistic goals that their younger peers, while Maslow's (1954) and Vaillant's (2002) work on psychosocial development indicate that they also have a desire to be generative both inside and outside their workplace. There was also evidence that participating in M-Level study improved both the social and identity capitals of participants (Bourdieu, 1986; Schuller, 2002).;The study findings indicate how both employers and HEI's could improve the support mechanisms available for such students. It also recommends that more effort be expended on making midcareer part-time students feel part of the University community.This thesis explores the perceptions and experiences of midcareer (aged 45 years and over) nurses and midwives attending a particular Higher Educational Institute (HEI) in Scotland to participate in part-time Health and Nursing programmes at master's level. Midcareer nurses are the largest group of currently registered nurses (NMC, 2019) and the number of midcareer nurses and midwives participating in master's level study is increasing. Despite this, very few research studies have been conducted looking at their views.;The aim of this descriptive phenomenological study was to bring to the fore the perceptions that midcareer nurses have about participating in master's programmes as older students in order to identify actions that can be taken forward to add to debates about the participation of midcareer professionals in higher education. Twelve midcareer nurses were interviewed, in depth, about their experiences.;Utilising Braun and Clarke's (2006, 2013b) framework for thematic analysis an overarching theme, 'Becoming a Confident Contributor' emerged. Participants revealed that they aspired to be 'confident contributors', valued for the knowledge and skills they brought to their teams, making efforts to improve themselves, others and their workplaces. Confident contributors also work towards creating a positive legacy as their careers advanced. Two subthemes 'Seeking recognition as a skilled practitioner' and 'The price of recognition' revealed the personal, social and cultural factors that impacted upon participants experiences. They discussed the factors that contributed to their recognition and boosted their self-esteem. This was not however without personal cost both inside and outside their workplaces. Participants also discussed their supports, the contribution of the HEI and the particular character required to succeed.;Viewing participants' experiences as a struggle for recognition (Honneth, 1994, 1995) provided the richest insight. However, it was not the only theoretical lens that helped to provide an understanding of the participants' involvement with the process of gaining a master's. Incentive theories suggest that midcareer nurses may have more altruistic goals that their younger peers, while Maslow's (1954) and Vaillant's (2002) work on psychosocial development indicate that they also have a desire to be generative both inside and outside their workplace. There was also evidence that participating in M-Level study improved both the social and identity capitals of participants (Bourdieu, 1986; Schuller, 2002).;The study findings indicate how both employers and HEI's could improve the support mechanisms available for such students. It also recommends that more effort be expended on making midcareer part-time students feel part of the University community
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