Saudi Cultural Missions Theses & Dissertations
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Item Restricted Perovskite Solar Cells Incorporated with Processing Additives(The University of Akron, 2024) Sawwan, Hussain; Gong, XiongThe increased use of solar energy for power is anticipated to lead to the shift from traditional power sources to renewable energy sources. Photovoltaic (PV) is a promising technology due to its ability to directly convert sunlight into electricity with no pollution. Solar cells, specifically those based on metal halide perovskites (MHPs) have gained popularity recently due to their power conversion efficiency (PCE) that have increased dramatically over the past 15 years, from 3.8% to more than 26 %. The rapid development in PCE is due to the advanced features that MHPs have such as cost-effective and easy processing, high absorption coefficient, large diffusion length, and low exciton binding energy. In particular, the purpose of this study is to develop solution-processed perovskite solar cells (PSCs) by tuning film morphology and optoelectronic properties of metal halide perovskites incorporated with processing additives, thereby optimizing the performance of PSCs. To maximize the potential of perovskite, controllable crystallization is crucial for producing high-quality perovskite thin films with fewer structural defects and additive engineering is a facile and effective method among other techniques. We mainly investigated the effects of various processing additives on the MHPs based on MAPbI3 perovskite (where MA is CH3NH3) and correlate PCE in term of film morphology, crystallinity, photocurrent hysteresis, optoelectronic properties, device performance and stability of PSCs.15 0Item Restricted PERFORMANCE OPTIMIZATION OF A PROTON EXCHANGE MEMBRANE WATER ELECTROLYZER(University of Delaware, 2024-07) Alkhaldi, Shabeeb; Ajay, PrasadGreen hydrogen can contribute significantly to combating climate change by helping to decarbonize the world's energy sector. Hydrogen can be produced in a carbon-free manner using renewable energy by electrolysis which is environmentally benign and produces hydrogen with high purity. Water is fed to the electrolytic cell as the reactant and it is dissociated into hydrogen and oxygen by the passage of electricity. Water electrolysis is typically accomplished today by one of three methods: (i) alkaline water electrolysis (AWE); (ii) solid oxide water electrolysis (SOWE); and (iii) proton exchange membrane water electrolysis (PEMWE). PEMWE offers certain advantages including high efficiency and high current density. Therefore, we focus on PEMWE in this study. First, we examine the effect of various operating parameters on PEMWE performance such as water flow rate, temperature, membrane thickness, flow field channel configuration, and porous transport layer properties. This work quantitatively compares the relative magnitude of anode water consumption against the concurrent water transport mechanisms of Fickian diffusion and electroosmotic drag as a function of the applied voltage. This study also gives insights on optimizing PEMWE performance by varying the operating parameters and provides a foundation for the design of a full-scale PEMWE system. Second, we evaluate multiple strategies for gas management in the PEMWE anode. In this study, we employ an electrolysis cell featuring a transparent anode to visualize oxygen bubble production and transport under a range of operating conditions. These strategies include changing the cell’s orientation with respect to gravity, increasing the water flowrate, and adding surfactant to the anode water supply. This study shows that optimally orientating the channels with respect to gravity can assist with oxygen bubble evacuation and improve performance. This study also captures the dynamic behavior of the two-phase flow phenomena in PEMWEs over a range of applied voltages. The results provide suggestions to enhance PEMWE performance by optimizing oxygen gas management within the PEMWE’s flooded anode. Third, we focus on the phenomenon of electroosmotic drag in an operating PEMWE with the goal of accurately measuring the electroosmotic drag coefficient. This study elucidates the effect of the cell temperature and membrane thickness on the relevant water transport phenomena. We also investigate the effect of supplying dry nitrogen to the cathode and provide an explanation for the improved current density based on the Nernst equation. Understanding these mechanisms is essential to improving PEMWE performance and efficiency. Finally, we compare the catalytic performance of nickel iron layered double hydroxide (NiFe LDH) against commercial iridium oxide (IrOx) in an anion exchange membrane water electrolyzer. In this study, we present the structural and performance analysis of NiFe LDH which was prepared in the form of nanosheets through a benzyl alcohol-mediated solvothermal process in one step. The NiFe LDH electrode demonstrated good stability over a 24-hour durability test. Although the electrochemical performance of NiFe LDH was somewhat lower compared to IrOx, it shows promise as a AEMWE catalyst due to its significantly lower cost and capacity for further activity enhancement.22 0Item Restricted Investigation of New Renewable Energy-based Multigeneration Systems for Saudi Arabia(Ontario Tech University, 2024-05-08) Altayib, Khalid; Dincer, IbrahimThis thesis explores three hybridized, large-scale solar thermal energy multigeneration systems: System 1 combines solar thermal energy with biomass, System 2 with geothermal, and System 3 with a petroleum coke and biomass blend. Each system provides power, heating, desalination, and other commodities. The thesis aims to develop energy system flowsheets integrating multiple technologies and assess their exergetic and economic benefits through case studies in KSA. Although the systems are of different kinds and scales, their economic parameters are found to be similar in terms of payback periods. System 1 achieves energy and exergy efficiencies of 50.4% and 45%, respectively. It generates annually 1040 GWh of electric power, 860 GWh of cogenerated heat, 80 GWh of refrigeration, 1100 tons of hydrogen, 26000 tons of chlorine gas, 11,600 tons of concentrated aqueous sodium hydroxide, 11,300 tons of ammonia, 1740 tons of aqueous urea, 905,000 m3 of fresh water. System 2 generates 700 GWh/year of power, 1200 GWh/year of heating, 27,100 tons/year of methanol, 130 million m3/year of fresh water, 42,500 tons/year of oxygen with efficiencies of 22% energy and 30% exergy. System 3 generates 1200 GWh/year of power, 690 GWh/year of heating, 12,700 tons/year of hydrogen, 19,300 tons/year of dried dates, 290,000 m3/year of fresh water and 80 GWh/year of cooling. The energy and exergy efficiencies of System 3 are 83.2% and 64%, respectively. For all systems, the chemical reactors are modelled using the Aspen Plus, which helps determine the best oxygen-to-biomass fraction in the gasifier as 15% at the turbine inlet temperature of 1500°C for System 1, the optimum methanol synthesis temperature in the range of 250°C-300°C for System 2, and results in 1.5 H2/C as the best molar ratio in hydro-gasifier to enhance the synthetic methane production rate for System 3. The thesis study underscores the potential of multigeneration and hybridization in improving the economics and ecology of renewable energy systems and offering insights applicable beyond the case studies explored.10 0Item Restricted Enhancing Efficiency in Cataract Surgery: A Lean Management Approach at Øjenlægernes Center(Saudi Digital Library, 2023-09-01) Altamimi, Saud; Expert, Paul; Hammett, Simon; Expert, PaulThe Øjenlægernes Center, specializing in cataract surgeries, efficiently conducts about 28 operations daily. However, there's potential to further improve patient flow, satisfaction, and efficiency. This research explores the surgery process, identifying areas for enhancement via lean management principles. Lean management, aimed at reducing waste without compromising productivity, has gained traction in healthcare. The study highlights opportunities in patient referral, appointment scheduling, waiting times, optometrist exams, consent form processes, and inventory management. Insights are drawn from success stories like the Wilmer Eye Institute and Hospital for Sick Children's eye clinic, which benefitted from lean's application. However, adopting lean in healthcare has its challenges, including resistance to change. A well-structured plan is crucial. The Aravind Eye Care System's success provides valuable lessons, emphasizing strategic operational changes. Recommendations for Øjenlægernes Center include a digital appointment system, optimizing optometrist exams, e-Consent forms, better inventory management, and reduced waiting times. Engaging all staff in the lean transformation process is crucial for success. In summary, though Øjenlægernes Center is operationally efficient, leveraging lean management can elevate its performance and patient satisfaction. Future studies should assess the long-term effects of these changes and their applicability in similar institutions. The research underscores lean management's potential in revolutionizing healthcare operations.18 0Item Restricted The Impact of Privatisation of state-owned enterprises in the United Kingdom and Saudi Arabia(2023-01-10) Alahmari, Abdulmajeed Awadh; Brook, OrThis paper reviews the motivation for the privatisation of public sector companies in both the UK and Saudi Arabia and their approach to the privatisation programme. This essay searched for the incentives and changes that contributed to changing the privatised company and its concept. In addition, there is consideration of the strategies for privatising companies and the work to achieve their goals in terms of improving efficiency to achieve growth and boost competition in the long- term, reduce government monopolies and save them from crises by altering their structure or addressing their lack of managerial experience. The British government privatised most public sector companies to address the lack of efficiency, reduce government spending and develop their structure. Meanwhile, the Saudi government’s approach to privatisation was motivated by the realisation of Vision 2030, one of the pillars of which was the privatisation programme and the achievement of national transformation in terms of achieving positive results from the efficient performance and structural development of companies subject to privatisation and legislative development by issuing a law to privatise companies. Therefore, privatisation succeeded in achieving most of its objectives. The paper concludes with the lessons learned by the two governments from the privatisation experience in terms of the importance of developing competition, the quality of company management, and the role of legislation in the effective regulation of companies.53 0