Saudi Cultural Missions Theses & Dissertations
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Item Restricted Enhancements to ADBSat: Implementation and verification of dynamic accommodation coefficient models(The University of Manchester, 2024) Aldakheel, Mshary Riyad; Crisp, NicholasThis work was motivated by the need to have accurate accommodation coefficient models in the ADBSat (Aerodynamic Database for Satellites) software. The current state of ADBSat software relies on generating aerodynamic databases for objects using fixed accommodation coefficients as input from the user, which doesn't consider the change in accommodation coefficient with the environmental changes. In this work, two dynamic accommodation coefficient models were implemented in the ADBSat software. The added dynamic accommodation coefficient functions complement ADBSat software and work on the same input the software requires to compute the aerodynamic coefficients for objects. The newly implemented dynamic accommodation coefficient model functions were verified and compared against an existing tool, the Vehicle Environment Coupling and TrajectOry Response (VECTOR) tool. The accommodation coefficient values generated from ADBSat agreed with the results generated using the VECTOR tool with a maximum error of less than 0.7\%. Finally, the newly implemented SESAM function was used in the ADBSat software to generate drag coefficients and derived density estimates for three satellite missions: GOCE(Gravity field and steady-state Ocean Circulation Explorer), CHAMP(CHAllenging Minisatellite Payload) and GRACE(Gravity Recovery And Climate Experiment), these results were compared with the results from ADBSat with fixed accommodation coefficient. Finally, The derived density estimates from ADBSat were compared to the NRLMSISE-00 (Naval Research Laboratory Mass Spectrometer and Incoherent Scatter Radar Exosphere) atmospheric density model estimates. ADBSat results with the SESAM provided better agreement with the NRLMSISE-00 in the GOCE and the CHAMP datasets, while for the GRACE dataset, fixed accommodation results provided better agreement with the NRLMSISE-00. The newly added dynamic accommodation coefficient models give spacecraft designers and analysts more accurate tools to model spacecraft aerodynamics and make better-informed decisions in the early design stages.16 0Item Restricted UNDERSTANDING GROUNDWATER DEPLETION AND WATER SECURITY CHALLENGES IN THE TRANSBOUNDARY AQUIFER SYSTEMS OF THE MIDDLE EAST AND NORTH AFRICA REGION(UNIVERSITY OF RHODE ISLAND, 2024) Alotaibi, Mohammed Obaid Altayyar; Akanda, Ali S; Thiem, Leon; Boving, Thomas; Inomura, KeisukeThe Arabian Peninsula countries are characterized by arid and semi-arid climates, relying heavily on groundwater as their primary source of freshwater. However, human activities are rapidly depleting and contaminating this resource, making its sustainable management increasingly crucial. Groundwater in these countries is stored in transboundary aquifer systems, such as the Wajid, Umm Er Radhuma, and Wasia, which are shared with Saudi Arabia, Iraq, Syria, Yemen, and Oman. These shared resources require Groundwater-sharing agreements for effective management. Yet, the lack of such agreements has resulted in poor data sharing, uncoordinated and unsustainable development, rapid water depletion, declining water quality, and land subsidence. In addition, this region is experiencing rapid development in infrastructure and industries, a trend that is significantly increasing groundwater extraction. Previous research has mostly focused on groundwater quality in the Arabian Peninsula and has yet to give importance to groundwater quantity and treatment for the Arabian Peninsula countries. Depletion has increased, and rainfall has decreased throughout the last 20 years. However, monitoring these resources and encouraging groundwater-sharing agreements are significant in sustaining and developing the water resources. Therefore, in this dissertation the three Arabian Peninsula aquifers have been compared with two North African aquifers, the Nubian Sandstone Aquifer System (NSAS) and Northwestern Sahara Aquifer System (NWSAS), which have groundwater treatment to identify suitable scientific methods for continuous groundwater monitoring, which can provide a comprehensive overview in the present and future to deal with this issue. As a result, the primary objective of this dissertation was to develop suitable methods for an integrated monitoring system of groundwater quality and quantity. This involved utilizing geophysical and field data of the aquifers, satellite remote sensing, and Geographic Information System (GIS). To achieve this, I combined the dams and agriculture data in Saudi Arabia, which occupies the largest area of the three Arabian Aquifers, and validated the results with remote sensing and satellite data. In addition, we compared the results with the aquifers that have treaties to create a suitable framework for continuous groundwater monitoring and preserve water resources in this region.26 0