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An investigation of the interventional role of perceived norms on greener choice
Full text linkEncouraging green consumption is a key goal of green marketing. However, the practice of green consumption often deviates from green attitudes. The approach of behavioural interventions can help reduce the deviation, i.e., the green attitude-behaviour gap, by influencing consumers’ decision-making. Nevertheless, this approach lacks a coherent theory underlying the promotion of green consumption behaviour, neglects the influence of self-consciousness on decision-making and intervention effectiveness, and has little recognition of its potential side effects on consumers’ well-being.To address this, this research, using a combined lens of decision-making and behavioural intervention, aims to investigate the impact of normative mechanisms as informational interventions on encouraging consumers to make greener choice and how selfconsciousness affects these interventional impacts.Three experimental studies in hotel towel reuse scenarios were conducted to achieve the aim. The findings reveal that both personal and social normative interventions are effective in promoting green consumption, and self-consciousness affects consumer responses to these interventions. The negative influence of private (public) selfconsciousness on the impact of personal (social) normative interventions provides insight into why some studies failed to produce intervention effects. In addition, the research suggests that the impact of intervention on self-concept clarity could reflect its effect on consumers’ well-being. By revealing the mediating role of green preference in normative interventions, this research bridges the causal process among personal norms, green preference, and greener choice. These findings have important implications for marketers and policymakers seeking to promote green consumption while ensuring the well-being of consumers. Focusing on personal norms can encourage sustained greener choice, as it relates strongly to green preference and further activates one’s private self-consciousness, providing well-being benefits due to increased self-concept clarity. Effective normative prompts for different marketing communication purposes can be crafted using the research's findings.Encouraging green consumption is a key goal of green marketing. However, the practice of green consumption often deviates from green attitudes. The approach of behavioural interventions can help reduce the deviation, i.e., the green attitude-behaviour gap, by influencing consumers’ decision-making. Nevertheless, this approach lacks a coherent theory underlying the promotion of green consumption behaviour, neglects the influence of self-consciousness on decision-making and intervention effectiveness, and has little recognition of its potential side effects on consumers’ well-being.To address this, this research, using a combined lens of decision-making and behavioural intervention, aims to investigate the impact of normative mechanisms as informational interventions on encouraging consumers to make greener choice and how selfconsciousness affects these interventional impacts.Three experimental studies in hotel towel reuse scenarios were conducted to achieve the aim. The findings reveal that both personal and social normative interventions are effective in promoting green consumption, and self-consciousness affects consumer responses to these interventions. The negative influence of private (public) selfconsciousness on the impact of personal (social) normative interventions provides insight into why some studies failed to produce intervention effects. In addition, the research suggests that the impact of intervention on self-concept clarity could reflect its effect on consumers’ well-being. By revealing the mediating role of green preference in normative interventions, this research bridges the causal process among personal norms, green preference, and greener choice. These findings have important implications for marketers and policymakers seeking to promote green consumption while ensuring the well-being of consumers. Focusing on personal norms can encourage sustained greener choice, as it relates strongly to green preference and further activates one’s private self-consciousness, providing well-being benefits due to increased self-concept clarity. Effective normative prompts for different marketing communication purposes can be crafted using the research's findings
The roles of Thailand Science Park in supporting the development of innovation clusters in Thailand : comparative case study - Thailand Science Park, Surrey Research Park, and Hong Kong Science and Technology Park
Full text linkThis thesis investigates the role of Science Parks (SPs) in supporting the development of Innovation Clusters (ICs), with a specific focus on Thailand Science Park (TSP). It adopts a comparative approach, examining the operational strategies of TSP alongside Surrey Research Park (SRP) in the UK and Hong Kong Science and Technology Park (HKSTP). The qualitative methodology is employed; questionnaires were emailed to 58 European and 13 Asian SPs, including SRP and HKSTP, to select two SPs for comparison with TSP. Subsequently, semi-structured interviews were conducted with 53 stakeholders from these three Parks.The study addresses three pivotal questions: Firstly, it explores how SPs in developing countries, like Thailand, differ in their approach to fostering long-lasting ICs compared to those in more developed economies. The research highlights unique challenges such as bureaucratic governance and cultural barriers, drawing lessons from HKSTP's flexible approach and collaborative culture. Secondly, the thesis delves into the management of R&D infrastructure, services, and networking in SPs. It reveals varied strategies across TSP, HKSTP, and SRP, underscoring the need for context-specific approaches in developing countries. Finally, the research examines the essential strategic elements for IC developmentin SPs, focusing on the necessity of support from policymakers and stakeholders in infrastructure, services, and financial backing. This research contributes significantly to the field by providing a comparative strategic analysis of SPs in various economic contexts, identifying strategies to address challenges, and emphasising the importance of public-private partnerships. Additionally, it offers insights into aligning performance indicators with SPs' goals, the criticality of rigorous tenant selection, and the evolving nature of infrastructure and innovation services in SPs.This thesis investigates the role of Science Parks (SPs) in supporting the development of Innovation Clusters (ICs), with a specific focus on Thailand Science Park (TSP). It adopts a comparative approach, examining the operational strategies of TSP alongside Surrey Research Park (SRP) in the UK and Hong Kong Science and Technology Park (HKSTP). The qualitative methodology is employed; questionnaires were emailed to 58 European and 13 Asian SPs, including SRP and HKSTP, to select two SPs for comparison with TSP. Subsequently, semi-structured interviews were conducted with 53 stakeholders from these three Parks.The study addresses three pivotal questions: Firstly, it explores how SPs in developing countries, like Thailand, differ in their approach to fostering long-lasting ICs compared to those in more developed economies. The research highlights unique challenges such as bureaucratic governance and cultural barriers, drawing lessons from HKSTP's flexible approach and collaborative culture. Secondly, the thesis delves into the management of R&D infrastructure, services, and networking in SPs. It reveals varied strategies across TSP, HKSTP, and SRP, underscoring the need for context-specific approaches in developing countries. Finally, the research examines the essential strategic elements for IC developmentin SPs, focusing on the necessity of support from policymakers and stakeholders in infrastructure, services, and financial backing. This research contributes significantly to the field by providing a comparative strategic analysis of SPs in various economic contexts, identifying strategies to address challenges, and emphasising the importance of public-private partnerships. Additionally, it offers insights into aligning performance indicators with SPs' goals, the criticality of rigorous tenant selection, and the evolving nature of infrastructure and innovation services in SPs
Beyond the lesbian vampire : representations of the violent lesbian in queer horror films of 2016–2019
No full textInvestigating streptomyces clavuligerus linear replicons for improved clavulanic acid production
Full text linkIncreasing antimicrobial resistance against ß-lactam antibiotics through bacterially produced ß-lactamases has prompted research into effective enzyme inhibitors, such as clavulanic acid. Streptomyces clavuligerus is the primary producer of clavulanic acid, which is used in various drugs such as Augmentin®. Streptomyces clavuligerus contains a dynamic genome and is composed of four giant linear plasmids (GLPs), pSCL1, pSCL2, pSCL3 and pSCL4 and its chromosome. Various genes essential for the maintenance of linear replicons, such as tap and tpg which encode telomeric terminal proteins (TPs), are found on three out of four GLPs (pSCL2, pSCL3, pSCL4). Previous work demonstrated a circularised chromosome and loss of plasmid after Cas9 mediated cleavage of the largest GLP, pSCL4, potentially due to the absence of tap-tpg. To determine the role of tap-tpg in chromosomal and plasmid linearity, we optimised and tested their inactivation using CRISPR-dCas9 multiplexing, targeting tap-tpg₄ on pSCL4, tap tpg₃ on pSCL3 and tap-tpg₂ on pSCL2. We used Illumina short-read sequencing to genotypically analyse our strains, which highlighted that the knockdown of multiple taptpg genes resulted in mutant strains with various combinations of lost plasmids and terminal ends. Noticeably, only the mutants with silenced tap-tpg4 demonstrated the loss of multiple plasmids, and pSCL2 loss was suggested to be a direct consequence of the CRISPR-dCas9 system, as all mutants and vector controls lost the plasmid. Additionally, we demonstrated chromosome circularisation and the loss of the 13-nucleotide binding site of Tap for our tap-tpg₄, tap-tpg₃ and tap-tpg₂ silenced mutant EM10, suggesting that overall tap-tpg expression levels in S. clavuligerus affect end-patching. The mutant strains were phenotypically characterised and mutants which had lost pSCL3, pSCL2 and/or pSCL1 had a significantly higher specific growth rate, therefore we confirmed that these replicons were essential for strain fitness. We also confirmed that S. clavuligerus does not require pSCL3, pSCL2 and pSCL1 for clavulanic acid production, as strains that had lost more replicons did not produce more clavulanic acid. Therefore, biotechnologically, the loss of replicons is of importance in terms of strain fitness rather than clavulanic acid production in S. clavuligerus. Moreover, to study the process of endpatching and determine the binding activity of TPs, overexpression of Tap4, Tap3 and Tap2 proteins was optimised and Tap4 was shown to potentially bind to the chromosomal ssDNA telomeres. With this study we have elucidated the importance of tap-tpg in the plasmid maintenance of S. clavuligerus and confirmed the essentiality of replicons, highlighting that whilst most replicons were dispensable, they are necessary for maintaining strain fitness and optimum growth.Increasing antimicrobial resistance against ß-lactam antibiotics through bacterially produced ß-lactamases has prompted research into effective enzyme inhibitors, such as clavulanic acid. Streptomyces clavuligerus is the primary producer of clavulanic acid, which is used in various drugs such as Augmentin®. Streptomyces clavuligerus contains a dynamic genome and is composed of four giant linear plasmids (GLPs), pSCL1, pSCL2, pSCL3 and pSCL4 and its chromosome. Various genes essential for the maintenance of linear replicons, such as tap and tpg which encode telomeric terminal proteins (TPs), are found on three out of four GLPs (pSCL2, pSCL3, pSCL4). Previous work demonstrated a circularised chromosome and loss of plasmid after Cas9 mediated cleavage of the largest GLP, pSCL4, potentially due to the absence of tap-tpg. To determine the role of tap-tpg in chromosomal and plasmid linearity, we optimised and tested their inactivation using CRISPR-dCas9 multiplexing, targeting tap-tpg₄ on pSCL4, tap tpg₃ on pSCL3 and tap-tpg₂ on pSCL2. We used Illumina short-read sequencing to genotypically analyse our strains, which highlighted that the knockdown of multiple taptpg genes resulted in mutant strains with various combinations of lost plasmids and terminal ends. Noticeably, only the mutants with silenced tap-tpg4 demonstrated the loss of multiple plasmids, and pSCL2 loss was suggested to be a direct consequence of the CRISPR-dCas9 system, as all mutants and vector controls lost the plasmid. Additionally, we demonstrated chromosome circularisation and the loss of the 13-nucleotide binding site of Tap for our tap-tpg₄, tap-tpg₃ and tap-tpg₂ silenced mutant EM10, suggesting that overall tap-tpg expression levels in S. clavuligerus affect end-patching. The mutant strains were phenotypically characterised and mutants which had lost pSCL3, pSCL2 and/or pSCL1 had a significantly higher specific growth rate, therefore we confirmed that these replicons were essential for strain fitness. We also confirmed that S. clavuligerus does not require pSCL3, pSCL2 and pSCL1 for clavulanic acid production, as strains that had lost more replicons did not produce more clavulanic acid. Therefore, biotechnologically, the loss of replicons is of importance in terms of strain fitness rather than clavulanic acid production in S. clavuligerus. Moreover, to study the process of endpatching and determine the binding activity of TPs, overexpression of Tap4, Tap3 and Tap2 proteins was optimised and Tap4 was shown to potentially bind to the chromosomal ssDNA telomeres. With this study we have elucidated the importance of tap-tpg in the plasmid maintenance of S. clavuligerus and confirmed the essentiality of replicons, highlighting that whilst most replicons were dispensable, they are necessary for maintaining strain fitness and optimum growth
Investigation and assessment of the benefits for power systems from wind farm control
Full text linkAs wind turbines are increasingly situated in large arrays offshore, connected to power grids by a single long cable, it is necessary to consider the operation of the whole wind farm as a single plant rather than as a series of individual units. To achieve this, the development of advanced wind farm modelling software is required to test and evaluate new control strategies for wind farm operation. This thesis considers the use of Strathfarm, The University of Strathclyde’s in-house wind farm modelling software, presenting novel wind farm control algorithms which significantly reduce the fatigue of wind turbine towers and wind turbine blades. The thesis also further develops Strathfarm in two key areas, presenting improvements to the modelled wakes and also details the development of a novel power system model. The power system model can be used to show the efficacy of previously developed dispatch algorithms for wind farms to support power grids.As wind turbines are increasingly situated in large arrays offshore, connected to power grids by a single long cable, it is necessary to consider the operation of the whole wind farm as a single plant rather than as a series of individual units. To achieve this, the development of advanced wind farm modelling software is required to test and evaluate new control strategies for wind farm operation. This thesis considers the use of Strathfarm, The University of Strathclyde’s in-house wind farm modelling software, presenting novel wind farm control algorithms which significantly reduce the fatigue of wind turbine towers and wind turbine blades. The thesis also further develops Strathfarm in two key areas, presenting improvements to the modelled wakes and also details the development of a novel power system model. The power system model can be used to show the efficacy of previously developed dispatch algorithms for wind farms to support power grids
Optimisation of energy and brightness transformer stages in a plasma Wakefield accelerator
Full text linkCapable of sustaining giga-volt-per-metre accelerating gradients, plasma accelerators are a promising technology that offer a path to compact machines for high-energy applications. In the case of a beam-driven plasma Wakefield accelerator (PWFA), energy is transferred from a driver particle beam to an existing bunch trailing in its wake; in this way, the plasma accelerator can be seen as an energy transformer. Alternatively a beam can also be formed directly inside the wake—a so-called plasma cathode. The quality of this new bunch can furthermore be higher than that of the incoming drive beam, where the plasma stage now acts as a brightness transformer.In the case of an energy transformer, this work focuses on an important quantity in plasma acceleration—the energy-transfer efficiency. Here, a new diagnostic was developed based on the light emitted from a beam-interacted plasma that can—in contrast to conventional dipole spectrometers—non-invasively measure the energy-transfer efficiency with longitudinal resolution on a shot-to-shot basis. After benchmarking this method with the spectrometer-based technique, local energy-transfer efficiencies of up to (58 ± 3)% were measured. Furthermore, the potential of this method in diagnosing transverse instabilities was investigated, with this diagnostic seen as being key to the monitoring and optimisation of future plasma accelerators.A PWFA-based plasma cathode stage was then also established and optimised, with the goal of demonstrating the brightness transformation of an input drive beam. Based on optically generated density downramp injection, bunches were internally injected with high reproducibility and accelerated with ∼ GVm−1 accelerating gradients. Thorough characterisation of these bunches yielded O(10pCMeV−1) peak spectral densities, percent level energy spreads and normalised emittances around an order of magnitude less than the drive beam. As a result, the 3D brightness of the injected bunches (i.e. brightness in the horizontal and spectral directions) was shown to be 4.8 times higher than that of the drive beam.Ultimately, both of the themes explored in this thesis are important if plasma accelerators are to meet the demands of future FEL light sources and linear colliders.Capable of sustaining giga-volt-per-metre accelerating gradients, plasma accelerators are a promising technology that offer a path to compact machines for high-energy applications. In the case of a beam-driven plasma Wakefield accelerator (PWFA), energy is transferred from a driver particle beam to an existing bunch trailing in its wake; in this way, the plasma accelerator can be seen as an energy transformer. Alternatively a beam can also be formed directly inside the wake—a so-called plasma cathode. The quality of this new bunch can furthermore be higher than that of the incoming drive beam, where the plasma stage now acts as a brightness transformer.In the case of an energy transformer, this work focuses on an important quantity in plasma acceleration—the energy-transfer efficiency. Here, a new diagnostic was developed based on the light emitted from a beam-interacted plasma that can—in contrast to conventional dipole spectrometers—non-invasively measure the energy-transfer efficiency with longitudinal resolution on a shot-to-shot basis. After benchmarking this method with the spectrometer-based technique, local energy-transfer efficiencies of up to (58 ± 3)% were measured. Furthermore, the potential of this method in diagnosing transverse instabilities was investigated, with this diagnostic seen as being key to the monitoring and optimisation of future plasma accelerators.A PWFA-based plasma cathode stage was then also established and optimised, with the goal of demonstrating the brightness transformation of an input drive beam. Based on optically generated density downramp injection, bunches were internally injected with high reproducibility and accelerated with ∼ GVm−1 accelerating gradients. Thorough characterisation of these bunches yielded O(10pCMeV−1) peak spectral densities, percent level energy spreads and normalised emittances around an order of magnitude less than the drive beam. As a result, the 3D brightness of the injected bunches (i.e. brightness in the horizontal and spectral directions) was shown to be 4.8 times higher than that of the drive beam.Ultimately, both of the themes explored in this thesis are important if plasma accelerators are to meet the demands of future FEL light sources and linear colliders
An exploratory study of key stakeholders' perspectives on soft skills development for employability: A multiple case study of Sri Lankan public universities
No full text
PU elastomers and grafted GO/PU nanocomposite with self-healing and self-adapting capabilities for next-generation electrical insulation
Full text linkThe demand for next-generation dielectric materials with substantially improved
reliability is spurred by the development of global energy industry, where extremely
harsh operating environment for electrical and electronic materials and increasingly
complex insulation system are present. In order to solve the problem of local electric
field distortion and electrical damage of insulating materials in high-voltage electrical
equipment, the development of a dielectric material with simultaneous self-healing and self-adaptive electrical properties is an enabling material to achieve this goal but has not yet been realised. In this study, the structure-activity relationship between the microphase-separated structure and the electrical properties of polyurethane elastomers (PUs) is clarified by investigating the morphology, chemical, and electronic structure of PUs with respect to their macroscopic insulating properties. Self-healing capability of electrical damage in PUs with high dielectric strength was achieved using reversible hydrogen bonding network and shape memory effect. By further grafting two dimensional graphene oxide (GO) nanosheets as the conductive backbone and regulating the concentration of nanoparticles and their interfacial states, it was shown that the GO/PU composites have excellent nonlinear response while retaining the self-healing capability, which has an excellent potential to be developed into a new generation of smart insulating materials. Firstly, the structure-activity relationship of PU elastomers is investigated comprehensively utilising quantum chemical simulation, chemical-physical structure characterisation and molecular relaxation behaviour to instruct the preparation of the desire PU materials. As a result of the inconsistency in the energy levels of the molecular orbitals between the internal soft segments (SS) and hard segments (HS), the microphase-separated PU possesses a deeper energy barrier between the SS and HS interfaces, which significantly enhances the insulating performance of the material.
Subsequently, the reversible hydrogen bonding network and shape memory effect of the screened PU with robust dielectric strength are verified by variable temperature infrared spectrum and calculated conformation entropy, respectively, which are the main driving forces to achieve the self-healing function. 2D optical micrographs, 3D computed micro-X-ray tomography, and cross-sectional SEM images all confirmed that the micro dendritic defects in the designed PU are completely healed under moderate thermal stimulation, while restoring its insulating strength evaluated by the maximum discharge amplitude (Qm) of the partial discharge. Additionally, isocyanate grafted GO nanosheets are introduced into the self-healing PU matrix with the purpose of enabling the nanocomposite to acquire self-adaptive capabilities. The nanocomposite with a 5% volume fraction of GO exhibits superior nonlinear electrical behaviour with a switching field strength of 0.7 kV/mm, a nonlinear
coefficient of 4.7, which are much better than those of traditional GO blended composites with a switching field strength of 8.5 kV/mm, a nonlinear coefficient of 2.3. The significantly improved nonlinear characteristic including the switching field strength and the nonlinear coefficient of the grafted nanocomposite is mainly attributed to the tailored interface between GO and PU matrix with considerably lowered interfacial energy barrier, as confirmed by quantum chemical calculations, nanoscale Kelvin probe force microscopy (KPFM) and macroscopic thermally stimulated current. The application of this grafted GO/PU nanocomposite exhibited excellent self-adaptive field grading capability at typical triple junction with field distortion. The grafted GO/PU nanocomposites reveal repeatable self-healing capabilities under the stimulation both of light irradiation and heating, involving the recovery of its novel nonlinear electrical properties and structural restoration. This versatile grafted GO/PU nanocomposite is expected to be promising for next-generation electrical insulation.The demand for next-generation dielectric materials with substantially improved
reliability is spurred by the development of global energy industry, where extremely
harsh operating environment for electrical and electronic materials and increasingly
complex insulation system are present. In order to solve the problem of local electric
field distortion and electrical damage of insulating materials in high-voltage electrical
equipment, the development of a dielectric material with simultaneous self-healing and self-adaptive electrical properties is an enabling material to achieve this goal but has not yet been realised. In this study, the structure-activity relationship between the microphase-separated structure and the electrical properties of polyurethane elastomers (PUs) is clarified by investigating the morphology, chemical, and electronic structure of PUs with respect to their macroscopic insulating properties. Self-healing capability of electrical damage in PUs with high dielectric strength was achieved using reversible hydrogen bonding network and shape memory effect. By further grafting two dimensional graphene oxide (GO) nanosheets as the conductive backbone and regulating the concentration of nanoparticles and their interfacial states, it was shown that the GO/PU composites have excellent nonlinear response while retaining the self-healing capability, which has an excellent potential to be developed into a new generation of smart insulating materials. Firstly, the structure-activity relationship of PU elastomers is investigated comprehensively utilising quantum chemical simulation, chemical-physical structure characterisation and molecular relaxation behaviour to instruct the preparation of the desire PU materials. As a result of the inconsistency in the energy levels of the molecular orbitals between the internal soft segments (SS) and hard segments (HS), the microphase-separated PU possesses a deeper energy barrier between the SS and HS interfaces, which significantly enhances the insulating performance of the material.
Subsequently, the reversible hydrogen bonding network and shape memory effect of the screened PU with robust dielectric strength are verified by variable temperature infrared spectrum and calculated conformation entropy, respectively, which are the main driving forces to achieve the self-healing function. 2D optical micrographs, 3D computed micro-X-ray tomography, and cross-sectional SEM images all confirmed that the micro dendritic defects in the designed PU are completely healed under moderate thermal stimulation, while restoring its insulating strength evaluated by the maximum discharge amplitude (Qm) of the partial discharge. Additionally, isocyanate grafted GO nanosheets are introduced into the self-healing PU matrix with the purpose of enabling the nanocomposite to acquire self-adaptive capabilities. The nanocomposite with a 5% volume fraction of GO exhibits superior nonlinear electrical behaviour with a switching field strength of 0.7 kV/mm, a nonlinear
coefficient of 4.7, which are much better than those of traditional GO blended composites with a switching field strength of 8.5 kV/mm, a nonlinear coefficient of 2.3. The significantly improved nonlinear characteristic including the switching field strength and the nonlinear coefficient of the grafted nanocomposite is mainly attributed to the tailored interface between GO and PU matrix with considerably lowered interfacial energy barrier, as confirmed by quantum chemical calculations, nanoscale Kelvin probe force microscopy (KPFM) and macroscopic thermally stimulated current. The application of this grafted GO/PU nanocomposite exhibited excellent self-adaptive field grading capability at typical triple junction with field distortion. The grafted GO/PU nanocomposites reveal repeatable self-healing capabilities under the stimulation both of light irradiation and heating, involving the recovery of its novel nonlinear electrical properties and structural restoration. This versatile grafted GO/PU nanocomposite is expected to be promising for next-generation electrical insulation
Unsteady hydrodynamics of ships moving in confined waterways
Full text linkWhen a ship is navigating on water surface, its resistance can be divided into three components: frictional resistance, eddy resistance, and wave-making resistance (Havelock, 1909). While in many cases, the steady component dominates the wave-making resistance, there are still certain instances where unsteady effects cannot be ignored. For example: • Sudden changes of boundaries, such as the width and depth of the waterway. This may occur when ships navigate in port, harbor or lock environments. It will potentially increase the risk of collisions or grounding incidents.• When a ship is overtaking (or being overtaken) or passing other vessels in busy waterways, the unsteady effects of the free surface can generate horizontal unsteady forces between the two ships. This can result in collisions between the vessels and lead to the blockage of the waterway.• Another typical scenario is when a ship keeps accelerating in open area,particularly in extremely shallow depths. In this case, the unsteady effects willsignificantly increase after the ship’s velocity exceeds the critical speed. At this point, the unsteady effects alter the flow field around the ship, resulting inchanges in wave-making resistance. This thesis posits that the aforementioned unsteady effects are closely correlated with unsteady waves on the free surface. Hence, the primary objectives of this research are two-fold:1) To develop a linear unsteady numerical program which is capable of simulating the unsteady free surface effects. This program will accurately capture the formation and evolution of unsteady waves.2) To devise a real-time updating mesh method that handles changes in waterway boundaries and depths encountered during the simulation process. Additionally, it ensures temporal continuity for all cells on the free surface.In this thesis, Chapter 1 will be an introduction and literature review of the research topic. Chapter 2 introduces the methodology used in this research. Chapters 3 to 5 constitute the main body of this thesis. Specifically, Chapter 3 presents the simulation of unsteady waves generated by a single object, with particular focus on the simulation of the previously mentioned scenario of a ship accelerating in shallow water. Chapter 4 aims to simulate multiple objects. In this chapter, the ship-to-ship problem and the unsteady bank effect within a confined waterway will be investigated. Due to the presence of interacting objects, the grid is required to be updated in real-time to accommodate changes in the boundary conditions. The simulation resultswill be compared with experimental data to validate their accuracy. Chapter 5 will build upon the foundation established in Chapter 3 by extending the grid handling techniques to account for unsteady banks. Additionally, the unsteady hydrodynamic model developed in Chapter 2 will also be incorporated. This integration will enable the simulation of the intricate wave phenomena that occurs during the process of a vessel entering a lock. The simulation results will be compared against experimental data as well as computational fluid dynamics (CFD) results to validate their accuracy. This comparative analysis serves to ensure the reliability and fidelity of the simulation outcomes. By undertaking these efforts, Chapter 4 aims to provide a comprehensiveunderstanding of the wave behaviour within the lock chamber during vessel entry, contributing to the advancement of knowledge in the field of unsteady water dynamics. Finally, Chapter 6 serves as the conclusion which summarizing all the achievements of this thesis and also proposing future directions for research.When a ship is navigating on water surface, its resistance can be divided into three components: frictional resistance, eddy resistance, and wave-making resistance (Havelock, 1909). While in many cases, the steady component dominates the wave-making resistance, there are still certain instances where unsteady effects cannot be ignored. For example: • Sudden changes of boundaries, such as the width and depth of the waterway. This may occur when ships navigate in port, harbor or lock environments. It will potentially increase the risk of collisions or grounding incidents.• When a ship is overtaking (or being overtaken) or passing other vessels in busy waterways, the unsteady effects of the free surface can generate horizontal unsteady forces between the two ships. This can result in collisions between the vessels and lead to the blockage of the waterway.• Another typical scenario is when a ship keeps accelerating in open area,particularly in extremely shallow depths. In this case, the unsteady effects willsignificantly increase after the ship’s velocity exceeds the critical speed. At this point, the unsteady effects alter the flow field around the ship, resulting inchanges in wave-making resistance. This thesis posits that the aforementioned unsteady effects are closely correlated with unsteady waves on the free surface. Hence, the primary objectives of this research are two-fold:1) To develop a linear unsteady numerical program which is capable of simulating the unsteady free surface effects. This program will accurately capture the formation and evolution of unsteady waves.2) To devise a real-time updating mesh method that handles changes in waterway boundaries and depths encountered during the simulation process. Additionally, it ensures temporal continuity for all cells on the free surface.In this thesis, Chapter 1 will be an introduction and literature review of the research topic. Chapter 2 introduces the methodology used in this research. Chapters 3 to 5 constitute the main body of this thesis. Specifically, Chapter 3 presents the simulation of unsteady waves generated by a single object, with particular focus on the simulation of the previously mentioned scenario of a ship accelerating in shallow water. Chapter 4 aims to simulate multiple objects. In this chapter, the ship-to-ship problem and the unsteady bank effect within a confined waterway will be investigated. Due to the presence of interacting objects, the grid is required to be updated in real-time to accommodate changes in the boundary conditions. The simulation resultswill be compared with experimental data to validate their accuracy. Chapter 5 will build upon the foundation established in Chapter 3 by extending the grid handling techniques to account for unsteady banks. Additionally, the unsteady hydrodynamic model developed in Chapter 2 will also be incorporated. This integration will enable the simulation of the intricate wave phenomena that occurs during the process of a vessel entering a lock. The simulation results will be compared against experimental data as well as computational fluid dynamics (CFD) results to validate their accuracy. This comparative analysis serves to ensure the reliability and fidelity of the simulation outcomes. By undertaking these efforts, Chapter 4 aims to provide a comprehensiveunderstanding of the wave behaviour within the lock chamber during vessel entry, contributing to the advancement of knowledge in the field of unsteady water dynamics. Finally, Chapter 6 serves as the conclusion which summarizing all the achievements of this thesis and also proposing future directions for research
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