SACM - United Kingdom
Permanent URI for this collectionhttps://drepo.sdl.edu.sa/handle/20.500.14154/9667
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Item Restricted Reliability Analysis of Monopile Offshore Wind Turbines: Addressing the foundation(University of Aberdeen, 2025) Alanazi, Abdulrahman Falah M; Sriramula, SrinivasOffshore wind turbines (OWTs) are essential for capturing renewable energy from wind in marine environments. However, the reliability of OWT systems, especially their monopile foundations, faces various environmental and operational challenges. This dissertation presents a comprehensive reliabiliity analysis of monopile offshore wind turbine systems, focusing on key failure modes such as scour, fatigue, and soil bearing capacity. Advanced probabilistic methods like First Order Reliability Method (FORM) , Second Order Reliability Method(SORM), and Monte Carlo Simulation(MCS) were used to quantify failure probabilities and assess system reliability. Detailed analyses for scour-related failures, fatigue damage, and soil bearing capacity were conducted using empirical data and modeling techniques. The scour analysis revealed a failure probability of 2.2800%, highlighting the importance of accurate scour depth predictions and effective mitigation strategies. The fatigue analysis showed a significant failure probability of 0.5037%, emphasizing the need for robust material selection and rigorous maintenance schedules. The soil bearing capacity analysis indicated a low failure probability of 0.0268%, underscoring the necessity for thorough geotechnical investigations. Fault Tree Analysis(FTA) and Reliability Block Diagram(RBD) were utilized to identify critical failure modes and evaluate overall system reliability. The FTAs for various components—including the foundation, rotor, blades, nacelle, and control system—provided insights into potential failure mechanisms and their probabilities. The RBD for the control system demonstrated an overall reliability of approximately 98%, indicating high system reliability under normal operating conditions. The overall system reliability was about 93%. The findings suggest several strategies to enhance the reliability of OWT systems, such as implementing advanced monitoring systems, optimizing design and material selection, and adopting proactive maintenance practices. Future research directions are proposed, focusing on advanced simulation techniques, material science innovations, and long-term performance data collection.16 0Item Restricted Enhancing Colorectal Cancer Screening Participation via Text Message Interventions(King's College London, 2024-09) Almoallem, Ghader; Round, Thomas; Hamad, WasimBackground: Colorectal cancer (CRC) ranks as the third most frequently diagnosed cancer globally and is a significant contributor to cancer-related deaths. Early detection through regular screening is crucial, as it greatly improves treatment outcomes and survival rates. However, screening participation for CRC remains insufficient, especially among minority groups. Text message interventions have been proposed as a cost-efficient and scalable solution to increase screening adherence. Objective: This systematic review and meta-analysis aimed to assess the effectiveness of text messaging interventions in enhancing CRC screening participation. Methods: A comprehensive search was conducted across four major databases Embase, PubMed, MEDLINE, and Cochrane up to August 2024. The review included randomized controlled trials (RCTs), observational studies, mixed-methods studies, and qualitative research that evaluated the impact of text message reminders on CRC screening rates. Data were extracted on study characteristics, intervention specifics, and screening outcomes. Meta-analyses were carried out to calculate pooled effect sizes of text message interventions compared to usual care. Results: Eighteen studies met the inclusion criteria, consisting of 12 RCTs, two observational studies, two mixed-methods studies, and two qualitative studies. The meta-analysis indicated that text message interventions significantly improved CRC screening uptake compared to usual care (pooled relative risk: 1.23, 95% CI: 1.12–1.36, p < 0.001). Sensitivity analyses validated the robustness of these results across different study designs and populations. Text message interventions were especially effective in low-income and underserved groups, where traditional outreach methods tend to be less successful. Furthermore, cost analysis from the reviewed studies highlighted that text messaging is a highly cost-effective method for promoting CRC screening. Conclusion: Text message interventions offer a scalable and effective approach to increasing participation in CRC screening programs. Their affordability, wide reach, and simplicity make them an ideal tool for public health systems, particularly those operating in resource-constrained settings. Despite these encouraging results, further research is needed to refine the content, timing, and cultural relevance of messages to ensure maximum impact across diverse populations. Incorporating text messaging into broader public health strategies could be crucial in alleviating the global burden of colorectal cancer.48 0Item Restricted The Swatch Group Valuation report (Dissertation)(Queen Mary University of london, 2023-12-16) Alhelali, Ahmed; Larcher, LucaThis is a comprehensive valuation report on the Swatch Group Ltd. A predominant company in the watchmaking and jewelry industry that specializes in luxury and mid-range watches, the Swiss company has been in business since 1983 and has a presence worldwide. In this report the company will be evaluated for an investment decision on whether to buy or sell depending on the value of the stock in the next five years, through the forecasted value of the company, this value will be calculated using valuation techniques that use financial reporting available to investors. For evaluating the swatch group and after researching the company and exploring its historical financial data, the use of the discounted cash flow (DCF) model is chosen to evaluate the present value of the company which gives us an insight into weather the company can generate profits for an investment or not, the investment decision on whether to buy or sell the company will be supported by the DCF model, a sensitivity analysis which gives us more alternate scenarios on the present value of the company based on the cost of capital and the growth rate, the relative valuation of the company which compares certain ratios with other similar companies of similar financial metrics and work in the same industry. Right now, the group is publicly traded on the Swiss stock exchange at a share price of 235.40 Swiss francs (CHF) as of September 29, 2023, and evaluating the company gives us a share price of 259.62 CHF with a 10% premium to the current share price, with that the recommendation is to buy the shares or add more shares to an existing portfolio.15 0Item Restricted Modelling and Sustainability Assessment of Industrial Ionic Liquid Production and Applications using Life Cycle Thinking(Saudi Digital Library, 2023-02-02) Baaqel, Husain; Hallett, Jason; Chachuat, Benoit; Guillen-Gosalbez, GonzaloThe main goal of this dissertation is to build on the current state-of-the-art research regarding ionic liquid (IL) sustainability assessment to help answer the research question, "how sustainable are ILs as alternatives to conventional technologies?" This is accomplished by developing a systematic computer-aided framework that integrates life cycle assessment (LCA) and life cycle costing (LCC) with process modelling and simulation for the consistent and complete economic and environmental assessment of ILs. The work further explores the use of monetization and an advanced framework that couples uncertainty analysis and global sensitivity analysis to enhance decision-making. The main novelties of the thesis are the methodological components and the case studies, in which the production of different ILs are evaluated in the context of relevant applications including their use. This thesis has contributed to the existing body of research by developing the following aspects. First, an integrated framework that combines LCA, LCC with process modelling and simulation was applied to evaluate the production of 1-butyl-3-methylimidazolium tetrafluoroborate using two synthesis routes and compare them with two conventional solvents in terms of their application in fuel desulfurization. Second, the developed framework was enhanced by incorporating factors of monetization, and this was applied to a case study involving hydrogen sulfate-based ILs to quantify their externalities and compare the true cost of these ILs with that of conventional solvents in biomass pretreatment applications. Finally, LCA uncertainty and global sensitivity analysis (GSA) was included in the framework to improve uncertainty analysis by accounting for process model uncertainties and identifying key parameters in non-linear systems, which was demonstrated in a case study involving the production of dialkylimidazolium ILs. The results show that the use of data from detailed process models, as highlighted in the holistic framework, makes a big difference compared to the use of simplified methods. Unlike short-cut methods, the framework accounts for process efficiency, emissions, and waste and covers a wide range of environmental impact categories for a more consistent and complete assessment. Additionally, coupling monetization with LCA can improve the assessment by turning a multiobjective problem into a single-objective problem, and hence, facilitating decision-making. The environmental externalities quantified through monetization reveal hidden costs that are usually overlooked when conducting a conventional economic assessment. Moreover, the importance of including foreground uncertainties in the uncertainty analysis was demonstrated by the results obtained from applying uncertainty-GSA analysis. In particular, foreground uncertainties can significantly overlap with the background uncertainties because of the multiplicative effect, which impacts decision-making. Furthermore, using GSA can help correctly identify uncertain parameters by accounting for collaborative effects in non-linear systems. Finally, case studies were used to test the efficiency of the developed framework and its methodological components. The contributions of this thesis build on the state-of-the-art economic assessment and LCA for ILs and support research on evaluating the sustainability of ILs and similar novel chemicals. This in turn will help us better understand the potential of such chemicals in terms of their sustainability performance as decision-making in most industries today is driven by policies pursuing sustainable development.26 0