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The Effect of Auditor Characteristics on the Quality of Segment Disclosures of Diversified Firms
No full textA Master of Science thesis in Accounting by Sarah Ahmed Elkelani entitled, “The Effect of Auditor Characteristics on the Quality of Segment Disclosures of Diversified Firms”, submitted in June 2024. Thesis advisor is Dr. Feras Salama and thesis co-advisor is Dr. Abed Al-Nasser Abdallah. Soft copy is available (Thesis, Approval Signatures, Completion Certificate, and AUS Archives Consent Form).Notwithstanding the increased prevalence of segment disclosure in firms’ annual reports, there is a paucity of empirical evidence on whether auditors affect the quality of these disclosures. This study attempts to fill this void in the audit literature by examining the impact of auditor characteristics on the quality of financial reporting at the segment’s level. We find that segment disclosure quality increases with auditor size and auditor expertise. We only find significant impact of tenure when the sample is split at the 5-year mark, with tenure less than 5 years leading to higher segment disclosure quality and tenure greater than 5 years leading to lower segment disclosure quality. In additional tests, we find that the impact of auditor’s attributes in enhancing segment disclosure quality decreases earnings management attributable to diversification and increases the excess value of diversification.School of Business AdministrationDepartment of AccountingMaster of Science in Accounting (MSA
Quality Degradation And Pricing of Perishable Food Products
No full textA Master of Science thesis in Engineering Systems Management by Haya Alastal entitled, “Quality Degradation and Pricing of Perishable Food Products”, submitted in December 2024. Thesis advisor is Dr. Malick Ndiaye. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Under ideal conditions, the cold supply chain for food products operates seamlessly, ensuring the preservation of quality from production to the point of sale. This ideal scenario involves maintaining precise temperature controls and consistent monitoring at every stage of the supply chain to prevent deviations that could compromise the product's freshness, nutritional value, or safety at any stage. However, the perishable food products industry faces significant challenges in maintaining optimal quality throughout the supply chain. Existing methods for capturing quality degradation often fall short, leading to potential risks such as temperature violations, loss of nutritional value, and pricing strategies that fail to adapt to the varying conditions of the cold supply chain. These misalignments frequently result in discrepancies between perceived value and pricing structures. To address these challenges, this thesis proposes an advanced quality monitoring system specifically designed for the cold supply chain of perishable and frozen food products. This system leverages existing technological advancements, such as smart indicator labels, integrated with Internet of Things (IoT) principles, and suggests an adaptive pricing model to the proposed system to dynamically adjust prices based on the perceived quality. To achieve this Gaussian Process Regression (GPR) was utilized for temperature and shelf-life predictions, combined with an innovative pricing algorithm using RGB values and Euclidean distance. Using GPR, the predictive models achieved high accuracy, with R-squared values of approximately 0.982 for temperature prediction and 0.981 for time estimation, indicating a strong correlation that improves efficiency and ensures the delivery of high-quality products while optimizing pricing structures to address the industry's unique challenges.College of EngineeringDepartment of Industrial EngineeringMaster of Science in Engineering Systems Management (MSESM
In-situ grown ternary metal hydroxides@3D oriented crumpled V₂C MXene sheets for improved electrocatalytic oxygen evolution reaction
No full textHigh valence multi transition metal hydroxides are greatly enriched with OER redox active sites due to strong synergy of heteroatomic nuclei. The efficiency of these redox active sites could be efficiently improved by coupling with highly conductive substrate. The advanced three-dimensional (3D) architecture and hydrophilic terminal functionalities of MXene (MX) considerably enhance the maximum utilization rate of anchored redox active sites by triggering the direct growth of these at MX substrate. Here-in, the freeze-dried 3D network of crumpled Vanadium-Carbide (V₂C) MX sheets regulates the crystallization of in-situ grown NiFeCr multi transition metal hydroxides on MX scaffold through co-precipitation process. The XPS results suggest a synergistic chemical interaction of 3D MX scaffold with NiFeCr that modifies the electronic structure of the composite ensuring reduced charge transfer resistance. Besides, as found in FESEM morphological investigation, the well-dispersed NiFeCr multi-transition metal hydroxides are immobilized on open pores like structure of V₂C-MX facilitate thoroughly accessible active sites. As a result, the NiFeCr@3D V₂C-MX composite has shown an excellent electrocatalytic activity with an overpotential of 410 mV at a current density of 200 mA cm⁻², Tafel slope of 100 mV dec in 1M KOH. Besides, the significant interaction between metallic centers and MXene support prevent detachment or agglomeration of active centers providing maximum interaction with the electrolytic ions, quick ionic OH⁻ transportation, speedy and stable electron transfer channels thus ensure the long-term stability of NV-5MX during 53 h continuous operation of OER. Furthermore, we have utilized a more accurate value of half-cell standard reduction potential of the Hg/HgO electrode in the Nernst equation to represent all test voltages and to determine the overpotential values. In essence, this study features a facile approach for the confined growth of multi transition metal hydroxides in the presence of morphologically unique 3D crumpled V₂C MXene architectures. Consequently, the increased OER reaction kinetics and improved stability of the synthesized composites are potentially due to synergistic interplay between well dispersed active sites and the conductive substrate.American University of Sharja
Numerical Evaluation of Shear Strength Enhancement in RC Beams Incorporating Various Web Opening Configurations and Pre-Stressed Fe-SMA Bar Sizes
No full textWeb openings in reinforced concrete (RC) beams are commonly required to accommodate utility ducts, pipes, and other service installations, optimizing space utilization and reducing construction costs. However, these openings can severely compromise the structural integrity of beams, mainly by lowering their shear strength, thus necessitating innovative reinforcement techniques to maintain their load-bearing capacity. This study presents a numerical investigation to enhance the shear strength of RC beams with various web opening shapes by integrating pre-stressed Fe-SMA (Iron-based Shape Memory Alloy) bars. The analysis focuses on two key parameters: the shape of the web openings and the diameter of the Fe-SMA bars. Finite element modeling was used to simulate RC beams with rectangular, circular, and diamond-shaped openings, and the impact of different Fe-SMA bar sizes on shear capacity was systematically evaluated. The results demonstrated that the incorporation of pre-stressed Fe-SMA bars significantly enhances the shear strength of RC beams, with the extent of improvement closely tied to both the geometry of the openings and the bar diameter. Under four-point loading, beams with diamond and circular openings exhibited fewer diagonal cracks and greater shear strength than those with square openings, especially when reinforced with larger Fe-SMA bars. Compared to the control beam (without opening), beams with diamond-shaped openings strengthened with 32 mm Fe-SMA bars showed the closest performance with only a 2% reduction in load capacity. In contrast, circular and square-shaped openings resulted in load reductions of 9.4% and 25.6%, respectively. These findings suggest that optimizing both the size of Fe-SMA bars and the shape of web openings is an effective strategy for enhancing the structural performance of RC beams with web openings
Study of the Impact of Land Use and Land Cover (LULC) Changes on local climate in Six Mega Global Cities in the 21st Century
No full textA Master of Science thesis in Civil Engineering by Lara Ali Sabobeh entitled, “Study of the Impact of Land Use and Land Cover (LULC) Changes on local climate in Six Mega Global Cities in the 21st Century”, submitted in July 2024. Thesis advisor is Dr. Tarig Ali and thesis co-advisor is Dr. Md. Mortula. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Urbanization, characterized by the rapid expansion of city areas and populations, is a significant trend of the 21st century, particularly in developing countries. This thesis investigates the impact of Land Use and Land Cover (LULC) changes on local climates in six major global cities—Beijing, Cairo, Delhi, Istanbul, Lagos, and London—from 2000 to 2023. Utilizing supervised machine learning algorithms, including Classification and Regression Trees (CART), Gradient Tree Boost (GTB), Random Forest (RF), and Support Vector Machine (SVM), Landsat imagery of these global cities was classified, integrating indices like NDVI, NDBI, and MNDWI to enhance LULC classification accuracy. The methodology involved obtaining and preprocessing satellite imagery, applying machine learning algorithms for LULC classification, and analyzing the relationship between LULC changes and local climate represented by land surface temperature (LST) utilizing the GEE platform. Additional data layers like elevation and slope were incorporated to improve model performance, and accuracy was assessed using the following metrics: overall accuracy, kappa statistics, and F-1 scores. The SVM proved to be superior to other algorithms. The findings revealed significant patterns of urban expansion and vegetation loss, highlighting the impact of urbanization on local climates. Urban areas experienced the highest expansions in Istanbul (137.8%) and Lagos (over 100%), while vegetation cover declined in all cities, with Lagos experiencing the highest reduction at 59%. These changes exacerbate urban heat island effects and increase climate-related vulnerabilities. Urbanization raises LSTs, while areas with more vegetation have lower LSTs. The study compared LULC change patterns and socioeconomic indices between developed, developing, and upper-middle-income countries, represented by the selected global cities. London showed a modest increase in developed areas (58.45%) compared to rapid urbanization in Cairo, Lagos, and Delhi. The findings highlight the need for customized urban planning and climate adaptation strategies, with enhanced international cooperation and support for sustainable urbanization initiatives in developing regions being crucial to mitigate the adverse effects of LULC changes on local climate, promoting sustainable urban areas.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE
Thermal Performance of Kresling Origami Structures as Deployable Heat Fins
No full textThis paper investigates the thermal performance of Kresling origami structures as deployable heat fins for enhanced thermal management. Origami-inspired designs offer unique advantages in heat dissipation due to their shape-transforming capabilities, enabling adaptive heat transfer solutions. The study focuses on both numerical and experimental analysis of Kresling origami fins, with the objective of understanding their conductive and convective heat transfer characteristics. Experimental measurements are conducted in a controlled wind tunnel environment enclosing a heated body with deployable origami fins. Further, a transient three-dimensional numerical model is developed based on the conservation principles of mass, momentum, and energy to simulate the heat transfer behavior. The results demonstrate that the use of Kresling origami fins significantly improves cooling performance, reducing the temperature of the heated body by up to 35.1% and 14.1% compared to a finless systems and traditionally finned system, respectively. Overall, the study demonstrates that Kresling origami offers promising potential as a deployable and efficient thermal management solution, especially in systems requiring adaptability and compactness
Motivational Factors Affecting Emirati English Learners
No full textA Master of Arts thesis in Teaching English to Speakers of Other Languages (TESOL) by Rachael Watt entitled, “Motivational Factors Affecting Emirati English Learners”, submitted in November 2024. Thesis advisor is Dr. Maria Eleftheriou and thesis co-advisor is Dr. Ozgur Parlak. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Emiratization has increased the number of UAE nationals in the private sector workforce, and these roles demand a higher level of English proficiency. Considering the increased demand for English proficiency, this study aims to understand the motivations of Emirati students toward learning English at the American University of Sharjah. By using a mixed-methods approach, it also compares the motivational factors between male and female students. The 23-item surveys adapted from Gardener’s AMTB included two open-ended questions about motivational and demotivational factors. The survey included Likert-scale questions to measure integrative and instrumental motivation, anxiety related to English classes, parental encouragement, and attitudes toward learning English. Through convenience sampling, the participants consisted of 38 Emirati students, 22 females and 16 males. The reliability of the survey was confirmed using Cronbach’s alpha, and data were analyzed using Mann-Whitney tests on SPSS to identify motivational factors. The findings reveal that both male and female Emirati students exhibit strong integrative and instrumental motivations for learning English, with female students generally exhibiting higher mean scores in both. Key motivational factors included career advancement and university goals, while significant demotivational factors comprised academic challenges and concerns about language identity. Although this study was limited to a single institution with a small sample size, it highlights the key motivational and demotivational factors of Emirati students learning English.
Understanding these factors is critical for educators and policymakers to develop effective English language learning environments in the UAE to support broader educational goals.College of Arts and SciencesDepartment of EnglishMaster of Arts in Teaching English to Speakers of Other Languages (MA TESOL
Exploiting the internal resonance in shunted circuit-based vibration suppression
No full textA Master of Science thesis in Mechanical Engineering by Khaled Al-Souqi entitled, “Exploiting the internal resonance in shunted circuit-based vibration suppression”, submitted in September 2024. Thesis advisor is Dr. Samir Emam. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Vibration reduction is an essential component of structural engineering that guarantees the functionality and endurance of numerous mechanical and architectural systems during design and maintenance. The field has been significantly improved in recent years with the introduction of piezoelectric materials, which provide novel solutions for regulating and mitigating vibrations. This thesis presents an approach to enhance vibration attenuation in cantilever structures by integrating piezoelectric patches and a shunt circuit, thereby advancing the field of vibration control in cantilever structures. The thesis begins with an introduction that provides a thorough overview of the classifications of vibration control and the importance attributed to vibration attenuation techniques. A comprehensive literature review aims to analyze previous studies and their methodologies in piezoelectric material vibration control is provided. A mathematical model that governs the dynamics of a cantilever beam combined with a piezoelectric transducer and a shunted circuit is developed. The model's initial emphasis is on the single-mode vibration occurring within a linear structure. The major innovation of this study is the systemic integration of a nonlinear electrical component that is introduced to activate the two-to-one internal resonance. The internal resonance is a nonlinear phenomenon that has demonstrated the potential to enhance the suppression of vibrations significantly. In order to attain optimal attenuation efficiency, the mathematical model is numerically simulated using MATLAB. This process includes modifying the shunt circuit's electrical parameters and tuning the absorber's frequencies with the structure’s natural frequency. Moreover, the model is extended to account for the nonlinearity of the host structure to examine the robustness of the proposed model. The main outcome of this study is a development in the domain of vibration control, providing a solution for engineering applications that require vibration attenuation that is both more effective and adaptable.College of EngineeringDepartment of Mechanical EngineeringMaster of Science in Mechanical Engineering (MSME
EEG-based brain source localization of mental stress using the SAFFIRE method
No full textA Master of Science thesis in Electrical Engineering by Nada Zahour entitled, “EEG-based brain source localization of mental stress using the SAFFIRE method”, submitted in April 2024. Thesis advisor is Dr. Hasan Al-Nashash and thesis co-advisor is Dr. Hasan Mir. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).College of EngineeringDepartment of Electrical EngineeringMaster of Science in Electrical Engineering (MSEE
Novel Sandwich Panel Design Integrating Structural Reinforcements with Polymeric Foam
No full textA Doctor of Philosophy Dissertation in Materials Science and Engineering by Assil Charkaoui entitled, “Novel Sandwich Panel Design Integrating Structural Reinforcements with Polymeric Foam”, submitted in June 2024. Dissertation advisor is Dr. Noha M Hassan and dissertation co-advisor is Dr. Zied Bahroun. Soft copy is available (Dissertation, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Sandwich panels, with their exceptional strength-to-weight ratio and energy absorption capabilities, are indispensable in many engineering applications. However, enhancing their impact protection and crashworthiness is becoming more pronounced. This research investigates the synergistic effects of various core topologies and fillings to enhance energy absorption capacities. This involved exploring variations in the core structure by comparing different unit cell shapes (X-frame, octet strut, H-frame, I-frame, and rhombus) and topological features (core volume fraction, core height, number of core layers, and unit cell direction), analysing functionally graded sandwich panels, and studying different core fillers. The study examined different materials for core filling, such as resin, silicon, and foam. The resin core filler was also strengthened with CNT to improve performance. A comprehensive Design of Experiments (DOE) approach was employed to explore the synergistic effects of the different variables. Numerical experiments were conducted using ABAQUS/CAE based on the experimental setup of a drop tower test. Regression analysis was used to investigate the numerical model responses and develop regression equations. Optimization techniques were then used to determine the optimum design parameters that maximize energy absorption using GAMS software. The optimization results showed that the X- frame core in the transverse direction with a volume fraction of 20% and a total core height of 30 mm provides the best combination for increasing energy dissipated in damage and recoverable strain energy while minimizing the overall mass of the structure. Moreover, results demonstrated the foam’s ability to enhance energy absorption capabilities in X-frame sandwich panels. The optimal X-frame design was integrated with a foam filler, enhancing the energy absorption capabilities further. Additionally, the functionally graded core of the X-frame sandwich panels, graded in the x-axis from the most to the least number of unit cells across three layers, showed a significant increase in energy absorption. Although resin-filled sandwich panels exhibited a brittle nature, the addition of CNT prevented perforation and significantly decreased the damage area on the sandwich panel. This research contributes valuable insights into the design and optimization of sandwich panels for enhanced impact resistance.College of Arts and SciencesMultidisciplinary ProgramsPhD in Materials Science and Engineering (PhD-MSE