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Design, production and testing of RF resonators and spin active material
Full text linkRF resonators with a resonance in the GHz range were designed, produced, and tested in a dilution refrigerator, along with the design and simulation of spin active material from 4H-SiC material. The resonators were designed to have a resonance frequency of 2GHz and 3GHz and obtained a frequency of 1.93GHz , 3.03GHz and 3.13GHz. Experimental results show that these resonances were
produced. The resonators were optimised to couple with spins, and design features were put in place to reduce energy loss to the environment. The resonators and the spin active material are thought to create a pairing which in the future could lead to a quantum memory for superconducting qubits.RF resonators with a resonance in the GHz range were designed, produced, and tested in a dilution refrigerator, along with the design and simulation of spin active material from 4H-SiC material. The resonators were designed to have a resonance frequency of 2GHz and 3GHz and obtained a frequency of 1.93GHz , 3.03GHz and 3.13GHz. Experimental results show that these resonances were
produced. The resonators were optimised to couple with spins, and design features were put in place to reduce energy loss to the environment. The resonators and the spin active material are thought to create a pairing which in the future could lead to a quantum memory for superconducting qubits
Protection challenges in future converter-dominated power systems : investigation and quantification using a novel flexible modelling and hardware testing platform
Full text linkThe research work presented in this thesis addresses anticipated (and documented) protection challenges that will be introduced by the domination of power electronics interfaces in future power systems. A flexible and programmable voltage source converter (VSC) model with controllable fault response has been developed and this is tested using realistic network data (including transmission lines and the corresponding power flow/fault level data) from the GB transmission network, provided by National Grid ESO (the research project sponsor).The results of tests, where a range of variations to the converter controllers’ fault-responses have been implemented (e.g. to reflect different detection and initial converter response delays, output current ramp rates and magnitudes), are presented and analysed. The simulated voltage and current waveforms are injected into actual protection relays using secondary injection amplifiers. The responses of the relays are recorded and a number of issues are highlighted, particularly with respect to the response of distance protection.It is shown that, when the system is dominated by converter-interfaced sources (especially where the sources are modelled as being unable to provide “fast” and “high” fault currents, which is typically the case for actual converter systems), the responses of traditional distance protection systems (and other systems relying on measurement of current magnitude) could be delayed, lose discrimination, e.g. by tripping with a zone 2 delay for a zone 1 fault, or may be completely unable to detect faults at certain locations within the system.Based on the test results, potential solutions are then presented relating to changes to relay algorithms and/or the requirements for converters in terms of behaviour during faults. The outcomes of the work will be of interest to grid code developers (publications arising from this work have already been referred to by ENTSO-E guidance document for national implementation for network codes on grid connection [1]), transmission network operators, other researchers and protection/converter manufacturers.An overview of future work, relating to comprehensive studies (using injection and the developed system/converter models) of a range of faults/ infeeds/ converter mixes with a wide range of protection relays including distance and unit-type, and development of a standard commissioning testing method of protection relays under future power system scenarios that are dominated by converters, is included in the concluding section. This will assist in the investigation and resolution of issues associated with protection performance in future converter-dominated power systems.The research work presented in this thesis addresses anticipated (and documented) protection challenges that will be introduced by the domination of power electronics interfaces in future power systems. A flexible and programmable voltage source converter (VSC) model with controllable fault response has been developed and this is tested using realistic network data (including transmission lines and the corresponding power flow/fault level data) from the GB transmission network, provided by National Grid ESO (the research project sponsor).The results of tests, where a range of variations to the converter controllers’ fault-responses have been implemented (e.g. to reflect different detection and initial converter response delays, output current ramp rates and magnitudes), are presented and analysed. The simulated voltage and current waveforms are injected into actual protection relays using secondary injection amplifiers. The responses of the relays are recorded and a number of issues are highlighted, particularly with respect to the response of distance protection.It is shown that, when the system is dominated by converter-interfaced sources (especially where the sources are modelled as being unable to provide “fast” and “high” fault currents, which is typically the case for actual converter systems), the responses of traditional distance protection systems (and other systems relying on measurement of current magnitude) could be delayed, lose discrimination, e.g. by tripping with a zone 2 delay for a zone 1 fault, or may be completely unable to detect faults at certain locations within the system.Based on the test results, potential solutions are then presented relating to changes to relay algorithms and/or the requirements for converters in terms of behaviour during faults. The outcomes of the work will be of interest to grid code developers (publications arising from this work have already been referred to by ENTSO-E guidance document for national implementation for network codes on grid connection [1]), transmission network operators, other researchers and protection/converter manufacturers.An overview of future work, relating to comprehensive studies (using injection and the developed system/converter models) of a range of faults/ infeeds/ converter mixes with a wide range of protection relays including distance and unit-type, and development of a standard commissioning testing method of protection relays under future power system scenarios that are dominated by converters, is included in the concluding section. This will assist in the investigation and resolution of issues associated with protection performance in future converter-dominated power systems
Enhanced static voltage stability and short circuit monitoring performance and optimization of future onshore AC power systems
Full text linkThis thesis presents several techniques focussed on improving characterisation,estimation and optimization of various factors associated with future power system strength and stability, that are markedly changing as the transition to renewable energy-dominated power systems continues. Changing systems strength in transmission and distribution networks are presenting unique regional challenges limiting the integration of low carbon technologies due to various constraints imposed on the network. These include fault level headroom constraints in MV distribution networks and steady state stability limits in transmission networks during periods of high power transfer. Specifically, a perturbation-coefficient based recursive least square (RLS) passive fault current estimation method, impedance matching bus-based and line-based staticstability indices and voltage stability-constrained optimal power flow (VSCOPF)models are presented to facilitate enhanced system performance in future lowinertia/strength power systems. Alternative to model-based strategies for conducting short circuit studies, measurement based short circuit monitoring has presented effective means to facilitate active fault level management functions and support flexible distributed generation connections in MV distribution networks. The application of passive and active fault level estimation is presenting alternative means to support embedded generation connections in fault level constrained regions. This research therefore proposes a perturbation coefficient-based technique for passive short circuit estimation utilising RLS based methodologies. This improves existing OLS processes in fault current estimation as parameter estimates are continuously updated via gain vectors with the sum of square of errors recursively minimised with additional load perturbation events identified. Enhancements in the accuracy of the proposed estimation method are demonstrated utilizing extensive simulation-basedstudies relative to conventional estimation methods. Declining system strength presents several challenges in monitoring and managing future networks with increased risks of classical voltage instability in weak networks identified as an emerging challenge. Novel static line-based and bus-based voltage stability indices are developed based on the ratio of load current flowing in a line tothe expected fault current flowing in the line and are based on impedance matching concepts during maximum power transfer. The proposed approach models shunt branch parameters, which have been historically neglected in two-bus equivalents and hence illustrate enhanced performance during stressed system conditions. Simulation based studies on multiple test networks have demonstrated improved detection capability of the developed stability indicator against several bespoke static line stability assessment methods. Index characterization considering solid state transformer (SST), constant voltage and constant power factor DG models are also presented to illustrate stability performance in future system conditions. The developed line index is incorporated into existing optimisation procedures for optimal generation dispatch with the inclusion of voltage stability criteria via voltage stability-constrained optimal power flow (VSCOPF). The proposed VSCOPF modelsincorporate the novel line stability indicator as part of an objective function in a multi-objective OPF formulation and as an inequality constraint. The proposed VSCOPF solution procedures demonstrate enhanced capability in increasing critical loadability, improved voltage performance, enhanced active/reactive generation dispatch and reduction in system losses relative to existing methods via simplified and robust calculation of proximity to collapse using static analysis techniques.This thesis presents several techniques focussed on improving characterisation,estimation and optimization of various factors associated with future power system strength and stability, that are markedly changing as the transition to renewable energy-dominated power systems continues. Changing systems strength in transmission and distribution networks are presenting unique regional challenges limiting the integration of low carbon technologies due to various constraints imposed on the network. These include fault level headroom constraints in MV distribution networks and steady state stability limits in transmission networks during periods of high power transfer. Specifically, a perturbation-coefficient based recursive least square (RLS) passive fault current estimation method, impedance matching bus-based and line-based staticstability indices and voltage stability-constrained optimal power flow (VSCOPF)models are presented to facilitate enhanced system performance in future lowinertia/strength power systems. Alternative to model-based strategies for conducting short circuit studies, measurement based short circuit monitoring has presented effective means to facilitate active fault level management functions and support flexible distributed generation connections in MV distribution networks. The application of passive and active fault level estimation is presenting alternative means to support embedded generation connections in fault level constrained regions. This research therefore proposes a perturbation coefficient-based technique for passive short circuit estimation utilising RLS based methodologies. This improves existing OLS processes in fault current estimation as parameter estimates are continuously updated via gain vectors with the sum of square of errors recursively minimised with additional load perturbation events identified. Enhancements in the accuracy of the proposed estimation method are demonstrated utilizing extensive simulation-basedstudies relative to conventional estimation methods. Declining system strength presents several challenges in monitoring and managing future networks with increased risks of classical voltage instability in weak networks identified as an emerging challenge. Novel static line-based and bus-based voltage stability indices are developed based on the ratio of load current flowing in a line tothe expected fault current flowing in the line and are based on impedance matching concepts during maximum power transfer. The proposed approach models shunt branch parameters, which have been historically neglected in two-bus equivalents and hence illustrate enhanced performance during stressed system conditions. Simulation based studies on multiple test networks have demonstrated improved detection capability of the developed stability indicator against several bespoke static line stability assessment methods. Index characterization considering solid state transformer (SST), constant voltage and constant power factor DG models are also presented to illustrate stability performance in future system conditions. The developed line index is incorporated into existing optimisation procedures for optimal generation dispatch with the inclusion of voltage stability criteria via voltage stability-constrained optimal power flow (VSCOPF). The proposed VSCOPF modelsincorporate the novel line stability indicator as part of an objective function in a multi-objective OPF formulation and as an inequality constraint. The proposed VSCOPF solution procedures demonstrate enhanced capability in increasing critical loadability, improved voltage performance, enhanced active/reactive generation dispatch and reduction in system losses relative to existing methods via simplified and robust calculation of proximity to collapse using static analysis techniques
Topics in Quantum Physics PH422 Exam Papers
No full textAccess restricted to staff and registered students of the University of Strathclyde.PAST EXAM PAPERS ARE NO LONGER BEING ADDED TO STAX. PLEASE VISIT SUPRIMO TO ACCESS AN UP-TO-DATE COLLECTION OF PAST EXAM PAPERS: https://suprimo.lib.strath.ac.uk
'Objectionable, mean and demeaning’ : the popularisation of vasectomy in Britain, c. 1920-1990
No full textProcess analytical technologies for particle characterisation and solid form analysis in continuous secondary pharmaceutical manufacturing
Full text linkA placebo formulation of granules produced during continuous twin screw granulation were studied on-line using a new dynamic image particle size analyser. A DoE approach was carried out in order to evaluate the image analysers ability to study granules produced in a way that represented a continuous manufacturing environment, something not yet reported in the literature. This study proved to be challenging due to fouling issues, however once these were addressed and eliminated, the process analysis technology (PAT) proved to be a useful tool for real time analysis of granules.A low frequency Raman spectrometer (LFRS), was introduced to in-line and off-line analysis of amorphous solid dispersions (ASD) produced by hot melt extrusion (HME).The study looked at the solubility of Affinisol and paracetamol in polymer matrices directly during HME. Structural phase transitions were observed during HME processes and were successful in determining crystalline and amorphous material in-lineand real time. Stability and homogeneity studies of varying concentrations of PCMAFF ASDs were studied. PCA was used to compare and validate LFRS to XRPD analysis.LFR results were also compared to DSC and Raman Spectroscopy. ASD’s with high concentrations of ASD were more unstable showing crystallisation over time.LFRS proved to be a good alternative to DSC and XRPD for solid state analysis. LFR was then applied to resolve a HME industrial issue. Different solid forms of Slaframine (SMZ) were produced using milling, cryo-milling, bulk material of Form II SMZ was then produced by crystallisation of FI to FII. The different solid states were then analysed using LFR. Classical least squares regressionanalysis was applied to mixtures of Form I, Form II and the Amorphous form of Sulfamerazine to look at the phase changes with time. LFRS studies determine the presence of unstable amorphous material produced during cryo-milling, somethingthat XRPD was unable to do due to long analysis times and the amorphous SMZ instability.A placebo formulation of granules produced during continuous twin screw granulation were studied on-line using a new dynamic image particle size analyser. A DoE approach was carried out in order to evaluate the image analysers ability to study granules produced in a way that represented a continuous manufacturing environment, something not yet reported in the literature. This study proved to be challenging due to fouling issues, however once these were addressed and eliminated, the process analysis technology (PAT) proved to be a useful tool for real time analysis of granules.A low frequency Raman spectrometer (LFRS), was introduced to in-line and off-line analysis of amorphous solid dispersions (ASD) produced by hot melt extrusion (HME).The study looked at the solubility of Affinisol and paracetamol in polymer matrices directly during HME. Structural phase transitions were observed during HME processes and were successful in determining crystalline and amorphous material in-lineand real time. Stability and homogeneity studies of varying concentrations of PCMAFF ASDs were studied. PCA was used to compare and validate LFRS to XRPD analysis.LFR results were also compared to DSC and Raman Spectroscopy. ASD’s with high concentrations of ASD were more unstable showing crystallisation over time.LFRS proved to be a good alternative to DSC and XRPD for solid state analysis. LFR was then applied to resolve a HME industrial issue. Different solid forms of Slaframine (SMZ) were produced using milling, cryo-milling, bulk material of Form II SMZ was then produced by crystallisation of FI to FII. The different solid states were then analysed using LFR. Classical least squares regressionanalysis was applied to mixtures of Form I, Form II and the Amorphous form of Sulfamerazine to look at the phase changes with time. LFRS studies determine the presence of unstable amorphous material produced during cryo-milling, somethingthat XRPD was unable to do due to long analysis times and the amorphous SMZ instability
Investigating the host defence peptide, LL-37, as an antimicrobial : a Raman microscopic approach
No full textSociety greatly relies on antibiotics which enable surgeries and treatments such as organ transplants and dialysis. However, The World Health Organisation (WHO) predicted antibiotic resistance could cause 10 million cases by 2050 if nothing is done. Bacteria can overcome the typically highly specific, slow-acting mechanisms of antibiotics by point mutation of target genes and horizontal gene transfer of genetic material between bacteria, for example. Alternatively, bacteria can increase antibiotic tolerance 10- to 1000-fold by growing biofilms: a community of bacterial colonies encased in a matrix of polymeric substances. The increased resistance is poorly understood, making biofilms difficult to treat. Thus, preventative antibiofilms are attractive therapeutics. Host defence peptides (HDP) are conserved within the immune system of all organisms. Resistance against them is thought to be low, due to their rapid, non-specific antimicrobial properties, and further immunomodulatory properties in vertebrates, making them attractive antibiotic alternatives. Moreover, they can reduce biofilm growth at sub-inhibitory concentrations. LL-37, known for modulating the human immune system and as an antimicrobial, is an excellent antibiofilm, but how this is achieved is unclear. Researching these properties, and biofilm growth in general, is challenging, often relying on destructive techniques or multiplexing chemical dyes to capture the full properties of the biofilm. Furthermore, HDPs are limited by their instability in serum. The overall aim of this research was to explore the non-destructive, label-free Raman microscopy in anti-biofilm research and the use of gold nanoparticles (AuNP) as a drug delivery mechanism to improve HDP stability. Both Raman spectroscopy coupled with chemometric analysis and stimulated Raman scattering (SRS) microscopy were good at capturing the subtle changes daily of an Escherichia coli (E. coli) biofilm. Furthermore, SRS showed that initial treatment of sub-inhibitory LL-37 delayed biofilm development. AuNPs were functionalise with LL-37 using several different methods. However, determining their efficacy against planktonic E. coli proved challenging. Growth inhibition was observed after 24 h treatment s This work showed Raman microscopy as an excellent technique for guiding antibiofilm research. However, further work is required to develop AuNP as a drug delivery mechanism for LL-37.Society greatly relies on antibiotics which enable surgeries and treatments such as organ transplants and dialysis. However, The World Health Organisation (WHO) predicted antibiotic resistance could cause 10 million cases by 2050 if nothing is done. Bacteria can overcome the typically highly specific, slow-acting mechanisms of antibiotics by point mutation of target genes and horizontal gene transfer of genetic material between bacteria, for example. Alternatively, bacteria can increase antibiotic tolerance 10- to 1000-fold by growing biofilms: a community of bacterial colonies encased in a matrix of polymeric substances. The increased resistance is poorly understood, making biofilms difficult to treat. Thus, preventative antibiofilms are attractive therapeutics. Host defence peptides (HDP) are conserved within the immune system of all organisms. Resistance against them is thought to be low, due to their rapid, non-specific antimicrobial properties, and further immunomodulatory properties in vertebrates, making them attractive antibiotic alternatives. Moreover, they can reduce biofilm growth at sub-inhibitory concentrations. LL-37, known for modulating the human immune system and as an antimicrobial, is an excellent antibiofilm, but how this is achieved is unclear. Researching these properties, and biofilm growth in general, is challenging, often relying on destructive techniques or multiplexing chemical dyes to capture the full properties of the biofilm. Furthermore, HDPs are limited by their instability in serum. The overall aim of this research was to explore the non-destructive, label-free Raman microscopy in anti-biofilm research and the use of gold nanoparticles (AuNP) as a drug delivery mechanism to improve HDP stability. Both Raman spectroscopy coupled with chemometric analysis and stimulated Raman scattering (SRS) microscopy were good at capturing the subtle changes daily of an Escherichia coli (E. coli) biofilm. Furthermore, SRS showed that initial treatment of sub-inhibitory LL-37 delayed biofilm development. AuNPs were functionalise with LL-37 using several different methods. However, determining their efficacy against planktonic E. coli proved challenging. Growth inhibition was observed after 24 h treatment s This work showed Raman microscopy as an excellent technique for guiding antibiofilm research. However, further work is required to develop AuNP as a drug delivery mechanism for LL-37
The formulation of public policy framework : encouraging effective collaboration within the electric bus research and manufacturing cluster to accelerate the adoption of electric buses in Thailand
Full text linkThe automotive industry is considered one of the largest sources of revenue for Thailand. However, with the recent acceleration of electric vehicle’s technological development around the world, the Thai government was concerned that the domestic automotive sector might be at risk of losing its competitive edge since the whole supply chain in the automotive industry is centred around products based on the research and manufacturing of internal combustion engine vehicles. Therefore, the Electric Vehicles Committee of Thailand was formed by the government to support and promote the transition of the automotive industry towards an electric vehicles economy. However, the complexity and sheer size of the Thai automotive industry; both in terms of the supply chain of physical products and the amount of information being exchanged among public and private stakeholders have made the adoption process of public policies extremely strenuous. This research aims to facilitate and quicken the process by designing a policy framework for the adoption of public policies within a smaller segment of the electric bus industry and use it as a possible model for the development of the Thai electric vehicles industry in the future. This framework consisted of integrated tools and concepts from engineering management perspective, combined with the data which was collected from the researchers, manufacturers, and stakeholders in Thailand. The main objective of the framework is to assist the initial stage of public policies initiation in electric bus research, manufacturing, and requisition, which will ultimately cultivate the development of the electric bus manufacturing industry in Thailand. Moreover, this policy framework could also be applied to other segments of public policy, or even in the formulation of operational strategy in both public and private organisations.The automotive industry is considered one of the largest sources of revenue for Thailand. However, with the recent acceleration of electric vehicle’s technological development around the world, the Thai government was concerned that the domestic automotive sector might be at risk of losing its competitive edge since the whole supply chain in the automotive industry is centred around products based on the research and manufacturing of internal combustion engine vehicles. Therefore, the Electric Vehicles Committee of Thailand was formed by the government to support and promote the transition of the automotive industry towards an electric vehicles economy. However, the complexity and sheer size of the Thai automotive industry; both in terms of the supply chain of physical products and the amount of information being exchanged among public and private stakeholders have made the adoption process of public policies extremely strenuous. This research aims to facilitate and quicken the process by designing a policy framework for the adoption of public policies within a smaller segment of the electric bus industry and use it as a possible model for the development of the Thai electric vehicles industry in the future. This framework consisted of integrated tools and concepts from engineering management perspective, combined with the data which was collected from the researchers, manufacturers, and stakeholders in Thailand. The main objective of the framework is to assist the initial stage of public policies initiation in electric bus research, manufacturing, and requisition, which will ultimately cultivate the development of the electric bus manufacturing industry in Thailand. Moreover, this policy framework could also be applied to other segments of public policy, or even in the formulation of operational strategy in both public and private organisations
The underrepresentation of women at senior leadership positions : investigating the impact of career management systems on women's career progression in the banking sector at the Sultanate of Oman
Full text linkPreviously held under moratorium from 22 May 2023 until 30 July 2025.The scarcity of women holding senior leadership positions is a well-documented
phenomenon in the literature that exists globally to date. The opportunities for
women’s career progression still lag significantly compared to those for men, despite
the equality legislations that were established to ensure that equal opportunities are
offered to men and women. The underrepresentation of women at senior leadership
positions implies that women are treated differently, and they continue to face
challenges that hinder their career progression. This research aims to investigate the
reasons behind the scarcity of women in leadership positions focusing on three main
areas. First, through the lens of career management systems. Second, through
examining the different barriers women face throughout their career journey, and also
explains the role of organisations in either perpetuating or challenging gender
inequalities that affect the career progression of women. Finally, it provides insights
on the interventions offered to women to help them climb the leadership ladder and
assesses the efficacy of these interventional strategies in the context of the continuing
scarcity of women in senior leadership positions.
This thesis adopted a qualitative dual case study design to explore, in depth, how
different organisational processes and practices play a major role in affecting women’s
career progression. To show different perspectives on the subject, a comparative study
between an international bank and a local bank in the Sultanate of Oman was carried
out. The data were collected through semi-structured interviews with employees from
different occupational levels including HR managers, senior managers, and other
occupational levels. The data collected were analysed by applying a thematic analysis
on the career trajectories of participants. These career trajectories revealed the different
career experiences that have been shaped by different decisions and factors, which
shows various steps towards progression or challenges that are encountered throughout
the career journey of the Participants. Investigating the career trajectory of both genders also highlighted the inequality issues between them, and the role played by the
organisations in addressing and overcoming these issues.
This research contributes to the discourse on gender inequality in career management
systems applied to women and proposes a conceptual framework to facilitate an indepth understanding of the different factors and barriers that impact the career
progression of women in the banking sector through career management practices. The
framework presents an overview of the contributors that will support women’s
progression in the banking sector, in addition to the barriers that could hinder their
career progression. Moreover, it provides insights for various sectors beyond banking
in forming policies that will improve the position of women and help them progress to
senior leadership positions.The scarcity of women holding senior leadership positions is a well-documented
phenomenon in the literature that exists globally to date. The opportunities for
women’s career progression still lag significantly compared to those for men, despite
the equality legislations that were established to ensure that equal opportunities are
offered to men and women. The underrepresentation of women at senior leadership
positions implies that women are treated differently, and they continue to face
challenges that hinder their career progression. This research aims to investigate the
reasons behind the scarcity of women in leadership positions focusing on three main
areas. First, through the lens of career management systems. Second, through
examining the different barriers women face throughout their career journey, and also
explains the role of organisations in either perpetuating or challenging gender
inequalities that affect the career progression of women. Finally, it provides insights
on the interventions offered to women to help them climb the leadership ladder and
assesses the efficacy of these interventional strategies in the context of the continuing
scarcity of women in senior leadership positions.
This thesis adopted a qualitative dual case study design to explore, in depth, how
different organisational processes and practices play a major role in affecting women’s
career progression. To show different perspectives on the subject, a comparative study
between an international bank and a local bank in the Sultanate of Oman was carried
out. The data were collected through semi-structured interviews with employees from
different occupational levels including HR managers, senior managers, and other
occupational levels. The data collected were analysed by applying a thematic analysis
on the career trajectories of participants. These career trajectories revealed the different
career experiences that have been shaped by different decisions and factors, which
shows various steps towards progression or challenges that are encountered throughout
the career journey of the Participants. Investigating the career trajectory of both genders also highlighted the inequality issues between them, and the role played by the
organisations in addressing and overcoming these issues.
This research contributes to the discourse on gender inequality in career management
systems applied to women and proposes a conceptual framework to facilitate an indepth understanding of the different factors and barriers that impact the career
progression of women in the banking sector through career management practices. The
framework presents an overview of the contributors that will support women’s
progression in the banking sector, in addition to the barriers that could hinder their
career progression. Moreover, it provides insights for various sectors beyond banking
in forming policies that will improve the position of women and help them progress to
senior leadership positions
Plasma-closing switch with corona electrodes: development and operational characteristics when filled with different gases
Full text linkHigh voltage gas-filled plasma closing switches are critical components of pulsed power systems due to their capability to operate in wide voltage and current ranges (from tens of amperes to hundreds of kiloamperes). They can handle high rates of change in currents and voltages, dI/dt, and dV/dt, and provide a short switching time with low jitter when operating in a triggered mode. The aims of this thesis are (i) to develop a novel, two-stage gas-filled plasma closing switch with corona electrodes and (ii) to investigate its operational performance in the self-breakdown and triggered operation regimes when filled with different environmentally friendly gases. The corona discharge electrodes used in the developed switch help to improve the switch’s operational stability providing minimal standard deviation in the self-breakdown voltage and minimal jitter in the case of the triggered operational mode. The operational performance of this plasma closing switch in both self-breakdown and triggered operation modes were investigated when the switch was filled with the selected gases (“Zero grade” air, N2, CO2, and a 90%/10% Ar/O2 mixture) withpressures up to 12 bar (gauge). The obtained experimental data and their statistical analysis allowed for a comprehensive analysis of different operational parameters of the developed switch depending on the gas type, gas pressure and polarity of the applied voltage. Experimental results have been used in the development of computational models. These analytical results contribute to a further understanding the dynamic characteristics of gas-filled spark-gap switches. The developed models can be used to optimise the parameters of a plasma closing switch filled with environmentally friendly gases to improve its operational performance.High voltage gas-filled plasma closing switches are critical components of pulsed power systems due to their capability to operate in wide voltage and current ranges (from tens of amperes to hundreds of kiloamperes). They can handle high rates of change in currents and voltages, dI/dt, and dV/dt, and provide a short switching time with low jitter when operating in a triggered mode. The aims of this thesis are (i) to develop a novel, two-stage gas-filled plasma closing switch with corona electrodes and (ii) to investigate its operational performance in the self-breakdown and triggered operation regimes when filled with different environmentally friendly gases. The corona discharge electrodes used in the developed switch help to improve the switch’s operational stability providing minimal standard deviation in the self-breakdown voltage and minimal jitter in the case of the triggered operational mode. The operational performance of this plasma closing switch in both self-breakdown and triggered operation modes were investigated when the switch was filled with the selected gases (“Zero grade” air, N2, CO2, and a 90%/10% Ar/O2 mixture) withpressures up to 12 bar (gauge). The obtained experimental data and their statistical analysis allowed for a comprehensive analysis of different operational parameters of the developed switch depending on the gas type, gas pressure and polarity of the applied voltage. Experimental results have been used in the development of computational models. These analytical results contribute to a further understanding the dynamic characteristics of gas-filled spark-gap switches. The developed models can be used to optimise the parameters of a plasma closing switch filled with environmentally friendly gases to improve its operational performance
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