SACM - United States of America
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Item Restricted Computational Study of Crossflow Patterned Hollow Fiber Vacuum Membrane Distillation(Saudi Digital Library, 2025) Asiri, Mohammed; Alparslan, OztekinLarge Eddy Simulations (LES) were conducted to investigate transport phenomena in hollow fiber Vacuum Membrane Distillation (VMD) modules. Most previous studies have investigated VMD, where the feed flow is in the same axial direction and the boundary layers remain attached to the membranes, resulting in a gradual decline in driving force and a decrease in flux toward the outlet. A crossflow-patterned hollow fiber module (HF-VMD), in which the feed enters across the bundle, moving orthogonal to the fibers from top to bottom, is considered in this research. Key performance indicators included permeate flux, temperature polarization coefficient (TPC), and concentration polarization coefficient (CPC). The results demonstrate that crossflow geometry outperforms parallel flow, enhancing flux by nearly 40% while suppressing polarization. Medium to high packing densities (50–75%) provide an effective balance between compact module design and stable flux, as indicated by the merit number. Increasing the Reynolds number improved mixing and mass transfer, peaking at Re = 1500 by 35%. A higher feed temperature was confirmed as the dominant driver of vapor transport, boosting flux by more than 55% at 353 K compared to 333 K. In contrast, extending the module length degraded performance by 14% due to accumulated polarization. Overall, this dissertation advances the understanding of heat and mass transfer in HF-VMD systems and provides practical guidelines for module optimization using high-resolution LES simulations. The findings identify crossflow HF-VMD modules as a promising pathway for next-generation desalination technology, particularly for large-scale applications.10 0Item Restricted ASPECTS OF COMBINATORIAL SPECTRAL THEORY AND COMMUTATIVE ALGEBRA(Saudi Digital Library, 2025) Suwayyid, Faisal; Wei, Guo-WeiThis dissertation advances algebraic and topological methods for data science through four lines of work. The first part introduces the path Dirac and hypergraph Dirac operators together with their persistent counterparts, and investigates their ability to capture harmonic and non-harmonic spectra while revealing informative subcomplex structure. Their sensitivity to filtration is analyzed, demonstrating how these operators adapt to topological changes, and their behavior is illustrated across diverse examples. A central application is to molecular science: strict preorders derived from molecular structure generate graphs and digraphs with rich path architecture, and the resulting path complexes encode information depth that varies with the underlying preorder classes. The second part develops Mayer Dirac operators on \(N\)-chain complexes. These operators link an alternating sequence of Mayer Laplacians and generalize the classical identity \(D^{2}=L\). An explicit Laplacian for \(N\)-chain complexes induced by vertex sequences on finite sets is derived, and weighted Mayer Laplacian and Dirac operators are introduced to capture physical attributes more effectively. A generalized factorization of Laplacians as an operator product with its adjoint is also established. Persistent Mayer Dirac operators and extensions are applied to biological and chemical data, where they demonstrate practical utility. The third part establishes a persistent Stanley–Reisner theory that connects commutative algebra with combinatorial algebraic topology, machine learning, and data science. The framework defines persistent \(h\)-vectors, persistent \(f\)-vectors, persistent graded Betti numbers, persistent facet ideals, and facet persistence modules. Stability analysis confirms that these algebraic invariants are robust under geometric perturbations, and their predictive value is demonstrated on molecular datasets. The final part proposes Commutative Algebra k-mer Learning (CAKL), a nonlinear algebraic framework for comparative genomics that builds upon persistent Stanley–Reisner theory. CAKL integrates commutative algebra, algebraic topology, combinatorics, and machine learning to address genetic variant identification, phylogenetic tree inference, and viral genome classification. Across eleven datasets, CAKL outperforms five state-of-the-art sequence analysis methods—particularly in viral classification—and maintains stable predictive accuracy as dataset size increases, highlighting scalability and robustness. Collectively, these contributions provide new operators, invariants, and learning paradigms that unify algebraic, topological, and combinatorial perspectives on discrete structures and real-world data, yielding great performance in molecular science and genomics.6 0Item Restricted Fintech, ESG Debate, Tax Ethics, Islamic vs Conventional Finance(Saudi Digital Library, 2025) Alshinkity, Hamed; K.Hassan, MohammadIn first chapter,Prevailing research on the interaction between board cultural diversity and Environmental, Social, and Governance (ESG) performance presents equivocal findings, particularly in emerging economies. This study ventures into an exploratory examination of this association, situated in the socio-cultural milieu of Asian countries. In this region, the lower social status of gender diversity often leads to a bias towards short-term perspectives. Drawing on the role of agency and stakeholder theory of prejudice toward board gender diversity: top management and women on board, this study aims to investigate the moderating role of board gender diversity in the knowledge sharing indicators on ESG controversies issues. The sample of this study includes 296 banks (52 Islamic, 244 conventional) with 2970 observations from 22 Asian countries during the 2013–2022 period. We further explore how the Board Specific Skills and audit Committee Expertise towards ESG varies positively, illustrating a more substantial effect of females on the board and across Islamic and conventional banks. Notably, we found that the impact of knowledge-sharing indicators on ESG controversies is less pronounced in Islamic banks, where the choices of board gender are more aligned with the conventional banks of emerging economies. Policymakers and leaders should, therefore, establish regulations that encourage knowledge-sharing mechanisms that promote sustainable activities, minimizing ESG issues, as suggested by additional analysis of ESG performance along with individual pillars. Corporate governance reforms in the form of gender diversity that aim to improve the effectiveness and efficiency of boards are critical for Islamic and conventional banks to attain both the financial and sustainable development of Asian economies.6 0Item Restricted Acomprehensive study of amyloid-beta kinetics and mechanism influenced by metal ions, chelation therapy, and inhibitor drugs in the treatment of Alzheimer’s disease(Saudi Digital Library, 2025) Alzahrani, Yasser; Yarahmadian, ShantiaAlzheimer's disease (AD) is a progressively developing neurological condition leading to cognitive and behavioral decline. The cause of AD is still unknown. Pathologically, hypotheses such as impaired neurotransmission, oxidative stress, metal ions, and amyloid-beta (A$\beta$) aggregation are vital contributors to AD's pathophysiology. Recent research focuses on treatments targeting the brain's A$\beta$ polymer deposits, commonly seen as amyloid plaques. Chapter 1 introduces AD, dissertation goals, and its outline. Chapter 2 provides a detailed scientific background on the pathophysiology of AD and key hypotheses from the literature and reviews recent drug treatment research. Chapter 3 aims to develop intuitive mathematical models to elucidate AD treatment with inhibitory drugs. These models clarify the complex kinetics of A$\beta$ formation and drug interactions. We discuss two categories of drugs: first, anti-inflammatory drugs (NSAIDs), which act as monomer inhibitors of A$\beta$ aggregation, and second, drugs that directly interact with A$\beta$ aggregated polymers. We initially analyze each drug independently and then assess their combined effects. Our numerical simulations demonstrate that the first type of drug reduces the equilibrium state value of aggregated filaments, whereas the second model of drug exhibits even greater efficacy in reducing the equilibrium state value of aggregated filaments. Furthermore, we conduct simulations of the simultaneous application of both drugs. The results are compared with the experimental data. Chapter 4 presents a novel and rigorously validated mathematical model to investigate the kinetics of ($A\beta$) aggregation in the presence of biologically relevant metal ions, chelating agents and inhibitor drugs. The model captures the microscopic reaction mechanisms that exist in the dynamics of $A\beta$ and explicitly accounts for the catalytic roles of copper, zinc, and iron ions, key contributors to the formation of neurotoxic plaques in AD. Clearly, our framework integrates dual therapeutic strategies: (i) metal chelation therapy, which binds and neutralizes free metal ions, and (ii) direct inhibition of $A\beta$ aggregation. Simulations in a variety of kinetic regimes reveal how each intervention modulates aggregation pathways, independently or synergistically. These studies focus on developing and analyzing mathematical models that describe the aggregation of $A\beta$ with and without metal ions under different inhibitor drugs and chelation treatment.8 0Item Restricted Exploring Teachers’ Perspectives on Digital Storytelling as a Tool in Saudi Kindergarten Classrooms: A Qualitative Multicase Study(Saudi Digital Library, 2025) Alahmdi, Ouhuud; Berson, IleneSaudi Arabia’s Vision 2030 emphasizes the importance of integrating digital technologies into early childhood education, with the goal of developing children’s skills for the 21st century from an early age and preparing them for the future. Digital storytelling is an effective and interactive multimodal strategy to enhance young children’s skills in the classroom. However, there is limited research examining how kindergarten teachers design and utilize digital storytelling in their classrooms. This qualitative multicase study aimed to explore how Saudi kindergarten teachers perceived and implemented digital storytelling as a tool to promote engagement and comprehension among young children. The study focused on how teachers designed and integrated multimodal elements—including visual, auditory, textual, and interactive media—into their digital stories, analyzing their approaches through the lens of the technological pedagogical content knowledge (TPACK) framework to understand how technological, pedagogical, and content knowledge informed their practice. This study aimed to contribute to the field of educational technology by providing practical evidence on the effectiveness of different modes of digital storytelling to promote young children’s engagement and comprehension skills, particularly within the Saudi educational system. The findings of this study provide insights that can help improve educational practices and guide future research efforts about digital learning in early childhood education in Saudi Arabia and similar environments.19 0Item Restricted Teachers’ and Administrators’ Perceptions of Digital Citizenship in K3 Private Schools in Saudi Arabia: A Case Study(Saudi Digital Library, 2025) Alnomei, Lamia Saad; Berson, IleneIt is crucial to integrate technologies into childhood education and teaching digital citizenship, but there are certain barriers to this integration in Saudi Arabia. Elicitation interviews were conducted in the context of this study with six participants, including kindergarten teachers and school leaders. They showed different levels of understanding the concept of digital literacy and citizenship and various levels of valuing technologies as tools for education. For instance, some expressed the need for more awareness and training, and other exhibited a deep understanding of digital citizenship. The study used Rogoff’s sociocultural theory, explored the influence of culture and parents on integrating technologies, and connected these goals with Saudi’s 2030 vision. To foster digital citizenship in early childhood education, a holistic approach is needed, and the integration of collaborative practices, cultural sensitivity, and technological is required.20 0Item Restricted Centering Decolonial and Environmental Counternarratives in Selected British, American, and African Literary Works(Saudi Digital Library, 2025) Alatawi, Majed; Wisnicki, AdrianThis study engages with a selection of African, British, and American literary works that represent various spaces, histories, and positionalities. Some of these works are Mary Shelley’s Frankenstein (1818), E. M. Forster’s A Passage to India (1924), María Ruiz de Burton’s Who Would Have Thought It? (1872), Pauline Hopkins’s Of One Blood (1902), Sophia Alice Callahan’s Wynema: A Child of the Forest (1891), Mohamed Al-Fayturi’s Diwan Al-Fayturi (1979), and Yvonne Vera’s Nehanda (1994). In reading such texts, the study explores the representations of the different manifestations of othering as a normalized sociopolitical phenomenon and the otherers’ dominant narratives in the diverse contexts of these texts and how minoritized voices respond to and take to task such narratives. Drawing on the frameworks of decoloniality, postcolonial ecocriticism, and environmental justice, the study argues that the works it examines present decolonial/environmental counternarratives. These counternarratives question, critique, and challenge the dominant narratives and the imbalanced power structures built on them by centering othered voices and worldviews and underscoring the suppressive strategies and oppressive structures that result from such dominant narratives. The study’s utilization of such critical lenses to read a diverse group of literary texts can help illuminate how silencing the voices of marginalized communities is central to building and maintaining oppressive power structures, especially in colonial and settler-colonial contexts where normalized othering impacts not only the othered human, but also the nonhuman world. Moreover, the human other in such contexts is often considered a part of the environment that the colonizers aim to commodify and dominate. In this light, the study examines the texts’ representations of the ways in which centering dominant worldviews and imposing their narratives reinforce oppressive power structures rooted in ideologies such as Eurocentrism and anthropocentricism. This has also entailed decentering indigenous worldviews, which tend to give more space to the nonhuman and consider humans a part of the ecological system instead of believing in their superiority to the natural world. As such, centering decolonial and environmental counternarratives makes possible a multivocality that resists the silencing and oppression of both the human and nonhuman others.37 0Item Restricted EXPLORING VIRTUAL REALITY IN PREOPERATIVE CLINICAL CARE: IMPACTS ON PATIENT ANXIETY, PARENTAL ANXIETY, AND NURSE SATISFACTION(Saudi Digital Library, 2025) Abu Rukbah, Walaa S; Wijesinghe, Dayanjan SAbstract EXPLORING VIRTUAL REALITY IN PREOPERATIVE CLINICAL CARE: IMPACTS ON PATIENT ANXIETY, PARENTAL ANXIETY, AND NURSE SATISFACTION By Walaa Abu Rukbah, Ph.D. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University. Virginia Commonwealth University, 2025 Major Director: Dayanjan S Wijesinghe, Ph.D. Associate Professor, Department of Pharmacotherapy and Outcomes Sciences Director, Laboratory of Pharmacometabolomic and Companion Diagnostics Introduction: Preoperative anxiety affects up to 65% of pediatric surgical patients, leading to increased stress responses, difficult anesthesia induction, and adverse postoperative outcomes. While pharmacological premedication remains standard practice, non-pharmacological alternatives like virtual reality (VR) show promise for anxiety reduction. This study evaluated the effectiveness and implementation feasibility of a custom-designed VR intervention for managing preoperative anxiety in pediatric patients, while assessing impacts on parental anxiety and healthcare provider satisfaction. Methods: A retrospective analysis was conducted using data from a nine-month quality improvement initiative (October 2023-June 2024) at VCU Children's Hospital. Eighty pediatric patients (ages 6-15 years) undergoing elective surgery received a custom VR intervention during preoperative waiting. Primary outcomes included changes in patient-reported distress (0-10 numerical rating scale) and fear (Children's Fear Scale 0-4) measured pre- and post-VR intervention. Secondary outcomes included physiological measures (heart rate, systolic blood pressure), parental anxiety (STAI-6), and stakeholder satisfaction ratings from patients, parents (n=65), and nurses (n=29). Logistic regression models identified predictors of clinically significant anxiety reduction (≥30% and ≥50% thresholds). Thematic analysis examined qualitative parent feedback to understand intervention mechanisms and stakeholder perspectives. Results: VR intervention demonstrated significant reductions in both patient distress (median change: -2.0 points, 95% CI [-2.00, -1.00], p<0.001) and fear (median change: -1.0 point, 95% CI [-1.00, 0.00], p<0.001). A majority of patients achieved a clinically significant reduction (≥30%) in both distress (66.2%) and fear (52.5%). Physiological measures showed significant decreases in heart rate (-5.8 bpm, p<0.001) and systolic blood pressure (-4.1 mmHg, p<0.0001). Baseline anxiety severity emerged as the strongest predictor of clinical response, with higher initial fear scores associated with increased odds of achieving ≥50% reduction (OR=1.80, 95% CI [1.11, 2.92], p<0.017). Stakeholder satisfaction was exceptionally high: 95.4% of parents would recommend VR to other families, 91.2% of children expressed willingness to use VR again, and 100% of nurses recommended VR for pediatric procedures. Parental anxiety significantly decreased following their child's VR intervention (P<0.0015), with 53.8% of parents experiencing improved anxiety levels. Qualitative analysis revealed predominant themes of engagement/distraction (52.4% of responses), emotional impact (34.9%), and clinical utility recognition (31.7%). Implementation was feasible with minimal workflow disruption (6.9% of nurses reported interference). Conclusion: Custom-designed VR interventions can be successfully integrated into pediatric preoperative care with significant clinical benefits and stakeholder acceptance. The intervention achieved meaningful anxiety reduction across multiple measures while demonstrating implementation feasibility in a busy clinical environment. Children with higher baseline anxiety levels experienced the greatest benefits, providing data-informed recommendations for targeted implementation strategies. The consistent of positive outcomes across patients, families, and healthcare providers, combined with minimal adverse effects (3.8%), supports VR integration as a valuable non-pharmacological approach to pediatric preoperative anxiety management. These findings add to the growing support for digital therapeutics in pediatric care and provide real-world guidance for healthcare systems considering VR implementation. Keywords: Virtual reality, pediatric anxiety, preoperative care, implementation science, non-pharmacological intervention, digital therapeutics13 0Item Restricted Effect of Artificial Aging and Cyclic Loading on Reverse Torque Values and Survival of Zirconia Implants with Carbon Fiber-Reinforced PEEK Polymer Screw(Saudi Digital Library, 2024) Alamri, Hassan Bilal A; Shereen, AzerStatement of problem: The introduction of carbon fiber-reinforced PEEK polymer screw in two-piece zirconia implants, facilitated the development of “metal-free" implant solutions. However, the literature lacks studies on the performance of such a screw joint assembly, particularly regarding reverse torque values. Purpose: To evaluate the effect of artificial aging and cyclic loading on reverse torque values and survival rates of carbon fiber-reinforced PEEK polymer screws in two-piece zirconia. Materials and Methods: A total of 20 implants were divided into two main groups. The testing group utilized 10 zirconia implants (NobelPearl Tapered RP 4.2 x 10 mm, Nobel BioCare, Kloten, Switzerland) with carbon fiber-reinforced polymer screws (VICARBO®, NobelPearl, Nobel BioCare, Kloten, Switzerland) to retain the zirconia crown cemented on zirconia abutments (NobelPearl abutment straight IX RP 1). The control group used 10 titanium implants (NobelReplaceTM Conical Connection, RP 4.3 x 10 mm, Nobel BioCare, Kloten, Switzerland) with titanium alloy screws (Clinical Screw Conical Connection, Nobel BioCare, Kloten, Switzerland) to retain zirconia crowns cemented on titanium abutments (Snappy abutment 5.5 CC RP 1.5, Nobel BioCare, Kloten, Switzerland). Implants were cemented into twenty glass cloth reinforced epoxy resin cylinders (G10, National Electrical Manufacturers Association, Rosslyn, Virginia, USA) using a dual-cured resin (Rock Core, Zest dental solutions, California, USA). All zirconia crowns were digitally designed to an identical shape maxillary central incisors, milled from zirconia blanks (IPS e.max ZirCAD Prime 25 x 98.5mm, Ivoclar, Vivadent USA), sintered, and then cemented with resin cement (Panavia V5, Kuraray Noritake, Okayama, Japan). A total of 60 screws were used in 6 groups. In the first two groups (T24 and Z24) a torque limiting wrench (NobelPearl Manual Torque Wrench, Nobel BioCare, Kloten, Switzerland) was used to deliver the manufacture's recommended torque values to all the samples, followed by another torque after 20 minutes. After 24 hours, a digital torque gauge (Chatillon Model DFS2-R-ND, Ametek, Largo, FL) was used to record the reverse torque values for all the samples. A new set of screws was then used for the next two groups (Tth and Zth). The same torque protocol was followed, and samples were subjected to thermocycling in 5 C, 55C distilled water baths for 10,000 cycles, and a dwelling time of 2 minutes. The reverse torque values were recorded again using the same digital torque gauge. The last two groups (Tcl and Zcl) received another new set of screws, and the same torque protocol was followed. After that, the samples were mounted at a 30° to the cyclic loading machine to be subjected to one million cycles of 200N load at a rate of (2 cycles/second (Hz)). When a failure was detected, the number of cycles at the time of discovery and failure mode were recorded. Preload efficiency values were calculated to standardize the reverse torque values of groups (T24,Z24,Tth and Zth). To compare the means of preload efficiency, a two-way analysis of variance was done followed by Tukey-Kramer post hoc analysis. The difference in number of cycles to failure between groups (Zcl and Tcl) was evaluated using the LIFEREG procedure of SAS. Results: Preload efficiency was 74.96% for T24, 72.17% for Z24, 76.4% for Tth and 63.96% for Zth. Results of the 2-way analysis of preload efficiency showed that the interaction was statistically significant (P = 0.0010), therefore, the pairwise comparisons between the 4 subgroups (T24, Z24, Tth and Zth) were adjusted by Tukey testing, which indicated that the preload efficiency of the zirconia group after thermocycling (Zth) was statistically significantly different from all other groups. The LIFEREG procedure of SAS did not detect a statistically significant difference in the number of cycles to failure between the groups (Tcl and Zcl). Furthermore, three zirconia implants, eight zirconia abutments, and two PEEK screws fractured during cyclic loading. One titanium implant exhibited minor deformation, while four titanium abutments and five titanium screws fractured. Conclusion. The preload efficiency of zirconia implants with PEEK screws was comparable to the titanium group after 24-hours of initial torque. However, after artificial aging, zirconia implants with PEEK screws exhibited a statistically significant decrease in preload efficiency compared to all other groups. No statistically significant difference was found in the number of cycles to failure between the zirconia and titanium systems.15 0Item Restricted Assessment of Wind Power Integration into the Synthetic Electric Grid of Saudi Arabia(Saudi Digital Library, 2025) Alonize, Mishal; Li, FangxingSaudi Arabia is working to reduce its dependence on oil and diversify its economy by incorporating renewable energy into its plans, as part of the initiative Vision 2030. A significant challenge in this change is the integration of renewable energy, particularly wind energy, into the existing Saudi Arabian electricity grid. Wind energy offers significant economic and environmental benefits, including reducing carbon emissions and providing a cost-effective energy source. However, integrating wind power presents challenges, particularly in maintaining grid frequency stability during different disturbances and ensuring that wind farms comply with grid codes to operate efficiently within the system. To perform tests for the effectiveness of wind integration, an adaptive synthetic Saudi electric grid model was built based on data of the Saudi power grid collected from open source data, designed to simulate the transient dynamics of a Saudi power grid, in order to enable simulation and assessment of wind energy integration into the electricity system of Saudi Arabia. For higher accuracy and details, the model created by CURENT Large-scale Testbed (LTB) and its ANDES package.12 0