https://repository.sustech.edu/handle/123456789/28467 Sat, 08 Aug 2026 05:52:53 GMT 2026-08-08T05:52:53Z https://repository.sustech.edu/handle/123456789/28475 The Stability Analysis of a Modified Cascade Control Strategy for Khartoum Refinery Delayed Coking Unit's Drums Ahmed, Lina Amer Alsharif; Hamed, Tomadir Awad Ibraheem The delayed coking unit is a process that converts heavy oil residues into more valuable products. The pressure control of the coking drums is important for process safety, yield, and stability. However, it has received limited study compared to temperature control. Cascade control is suitable for many industrial processes, especially when enhanced by combining proportional (P), integral (I), and derivative (D) actions in the control loops. This study focused on modifying a previous cascade control strategy developed to control the pressure inside the coking drums at Khartoum Refinery by controlling the heating fuel flow rate. The modification included replacing the Proportional (P) controller in the secondary loop with Proportional-Integral (PI) and Proportional-Integral-Derivative (PID) controllers to evaluate their impact on the overall control system stability. MATLAB simulations were used to calculate system transfer functions and test stability through direct substitution, root locus, Bode plots, and step response analysis. The results showed instability with both controllers due to reduced phase margins and increased high-frequency noise. Several control strategies were recommended to enhance the system performance, such as Lead/Lag compensators, Model Predictive Control (MPC), and State Feedback control. Sat, 23 May 2026 00:00:00 GMT https://repository.sustech.edu/handle/123456789/28475 2026-05-23T00:00:00Z https://repository.sustech.edu/handle/123456789/28474 التصور القرآني للبناء والعمران: قراءة هندسية آدم, فتح الرحمن محمد; حبيب, الطيب عبد اللطيف تُعنى الهندسة المدنية بتطوير البنية التحتية، بما في ذلك المباني والطرق وشبكات المياه والصرف الصحي، بما يسهم في خدمة المجتمعات البشرية. وعلى مر العصور، أسهم الباحثون في إرساء القواعد العلمية والمعرفية لهذا المجال. يهدف هذا البحث إلى استكشاف أوجه التقاطع المعرفي بين مفاهيم الهندسة المدنية والدلالات المتعلقة بالبناء والعمران الواردة في القرآن الكريم.، بهدف تأصيل المعرفة الهندسية وربطها بالوحي. ولتحقيق ذلك، اعتمدت الدراسة منهجاً تحليلياً لاستخراج الآيات القرآنية المتعلقة بالتشييد وتفسيرها باستخدام برنامج "الباحث القرآني" وأدوات الذكاء الاصطناعي. ركزت الدراسة على تحليل المكونات الإنشائية الأساسية، كالقواعد (الأساسات)، الأعمدة، والأسقف، بالإضافة إلى تقييم مواد البناء المذكورة في النص القرآني. وتوصلت النتائج إلى وجود توافق دقيق بين الإشارات القرآنية والمبادئ الحديثة للهندسة المدنية، مما يعكس إعجازاً علمياً مبكراً في هذا المجال. وتوصي الدراسة ب ضرورة توظيف هذا التأصيل المعرفي لتطوير حلول هندسية مستدامة ومبتكرة لمواجهة التحديات العمرانية المعاصرة. Sat, 23 May 2026 00:00:00 GMT https://repository.sustech.edu/handle/123456789/28474 2026-05-23T00:00:00Z https://repository.sustech.edu/handle/123456789/28472 Hydrogeological Investigation and Well Inventory Study in Lar Agricultural Scheme – Sudan Babiker, Elgaily M.; Osman, Khalid Abdelfattah M.; Elmamoun, Mohamed E. Irrigated agricultural LAR scheme in Merowe locality commenced in 2007. Since 2016, the surrounding area has been subjected to a rise in the groundwater table to the land surface, i.e., waterlogging. As a consequence, a lot of houses in the Elregaila region, just adjacent to the main canal, have fallen down. The paper aimed to study this phenomenon in order to propose ample solutions and further mitigation actions. Geophysical and hydrogeological investigations were conducted, and irrigation practice was studied to understand different aspects of the problem. The investigations showed that the main aquifer consists of Nubian Sandstone layers including pebbly sandstone and coarse to medium sandstone intercalated with mudstone. The aquifer area has an annual accumulation (water depth) of 1 to 1.8 m as a result of continual irrigation with approximate storage of 8 million cu m/year and annual abstraction about 1.5 million cu m/year. In accordance with the situations mentioned, it implies that the design of the irrigation conveyance system should be reviewed and weaknesses must be repaired and rehabilitated. Irrigation practice must be changed, as overwatering is a noticed tradition. Integrated irrigation policy using groundwater should be implemented Fri, 29 May 2026 00:00:00 GMT https://repository.sustech.edu/handle/123456789/28472 2026-05-29T00:00:00Z https://repository.sustech.edu/handle/123456789/28471 Classical Vector Space-based Semantic Representation and Dimensionality Reduction for Arabic Text Clustering: a survey Nooreldeen, Ebtihal; Zanaboni, Anna M. The Arabic language poses many challenges for automatic text processing due to its linguistic complexity, including rich morphology, the use of diacritics, and the frequent omission of vowels in written text. In general, two key factors significantly influence performance in text processing: the incorporation of semantic information in document representation and the control of dimensionality. This paper presents a survey of Arabic document clustering employing classical vector space models for text representation (as opposed to dense embedding models), with a particular focus on semantic representation and dimensionality reduction. The survey explores several applications of clustering, such as text summarization and information extraction, and reviews existing comparisons between clustering algorithms. Although classical vector space methods provide a somewhat limited perspective, the body of work found, covering the period from 2001 to 2025, is quite diverse. Key challenges, major findings, and the Arabic document corpora used in the reviewed literature are concisely presented in comprehensive synoptic tables. Tue, 03 Feb 2026 00:00:00 GMT https://repository.sustech.edu/handle/123456789/28471 2026-02-03T00:00:00Z