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Design and Optimization of a Planar Cable Robot
No full textA Master of Science thesis in Mechatronics Engineering by Mohamad Hassan Kassem entitled, “Design and Optimization of a Planar Cable Robot”, submitted in July 2020. Thesis advisors is Lotfi Romdhane and Mohammad Jaradat. Soft copy is available (Thesis, Approval Signatures, Completion Certificate, and AUS Archives Consent Form).This thesis presents a new approach towards the design of Cable-Driven-Parallel Robots (CDPR). Typically, the design of such robots is not the main concern, whereas in this work, an optimization of the design is carried out to minimize the consumed energy during a given task. First, a simulation of a simple design, using a software called CASPR, is performed to serve as a validation of the developed model. This latter is then used in the optimization algorithm, where the objective function is the sum of the maximum tensions during the performance of the task. The primary goal is to determine the best design that requires the minimum resultant tensions in the cables while the end effector is following a random trajectory within the achievable workspace. The optimization algorithm aims at minimizing the objective function, based on the validated model, under constraints. The algorithm is implemented under Matlab. The positions of the centers of the different pulleys are the main variables of this problem. The optimum locations of the pulleys are the main results of the algorithm. To further validate the model, an experimental setup was built to test the CDDR to follow a simple trajectory. Preliminary experimental results were obtained showing the motion of the end-effector along the desired trajectory. Different tools were used to conduct the optimization and the results were compared. It is concluded that the obtained design is the best in minimizing the required tensions, for the selected tasks.College of EngineeringMultidisciplinary ProgramsMaster of Science in Mechatronics Engineering (MSMTR
Self-Powered Balun Low Noise Amplifier with Degeneration Balancing and Thermal Noise Analysis
No full textA Master of Science thesis in Electrical Engineering by Qusai Mohammad Abubaker entitled, “Self-Powered Balun Low Noise Amplifier with Degeneration Balancing and Thermal Noise Analysis”, submitted in May 2020. Thesis advisors is Lutfi Albasha. Soft copy is available (Thesis, Approval Signatures, Completion Certificate, and AUS Archives Consent Form). Embargo expires February 25, 2021.The Balun low noise amplifier (LNA) is an LNA that exploits a combination of a common-source (CS) and a common-gate (CG) transistor, which cancels the noise and distortion of the CG stage. And since the CG is known to be linear, only the CS needs to be carefully designed and optimized. In this thesis, the CS section will be fully analyzed, and shown how the condition set in the literature review still satisfies the balancing output and cancels the CS stage thermal noise as well as the CG thermal noise. Also, forward body biasing (FBB) is used to reduce the threshold voltage and in addition, CS degeneration resistor will be studied to balance the output and cancel the
thermal noise of the transistors. The circuit is tested using UMC180nm on Cadence. The LNA achieves a gain of 19-16dB, NF<3.6 dB over the bandwidth 0.2-1.9GHz without a CS degeneration. A 17.8-14.8dB gain, a NF<3.8 dB over the bandwidth 0.2- 2.1GHz and power consumption of 12mW in both cases. Although outside the bandwidth, at ISM 2.4GHz a gain of 14.5dB and a NF of 3.8 is achieved, making it suitable for wireless sensor node (WSN) applications. According to the authors’ knowledge, this is the first time the degeneration resistor noise analysis on a Balun LNA is derived and simulated. Also, an RF harvester will be studied and used to power the Balun LNA. A two stage Dickson charge pump using MOSFET connected diode is chosen for this application. Although the efficiency is around 40%, the harvester was successfully integrated to the LNA, and its noise figure added to the output of the LNA.College of EngineeringDepartment of Electrical EngineeringMaster of Science in Electrical Engineering (MSEE
Cryogenic Drilling of AZ31 Magnesium Syntactic Foams
No full textMachined surface quality and integrity affect the corrosion performance of AZ31 magnesium composites. These novel materials are preferred for temporary orthopedic and vascular implants. In this paper, the drilling performance of AZ31-magnesium reinforced with hollow alumina microsphere syntactic foam under LN2 cryogenic, dry, and Almag® Oil is presented. Cutting tests were conducted using TiAlN physical vapor deposition (PVD) coated multilayer carbide and K10 uncoated carbide twist drills. AZ31 magnesium matrices were reinforced with hollow alumina ceramic microspheres with varying volume fractions (5%, 10%, 15%) and average bubble sizes. Experimental results showed that the drilling thrust forces increased by 250% with increasing feed rate (0.05 to 0.6 mm/tooth) and 46% with the increasing volume fraction of alumina microspheres (5% to 15%). Cryogenic machining generated 45% higher thrust forces compared to dry and wet machining. The higher the volume fraction and the finer the average size of hollow microspheres, the higher were the thrust forces. Cryogenic machining (0.42 μm) produced a 75% improvement in surface roughness (Ra) values compared to wet machining (1.84 μm) with minimal subsurface machining-induced defects. Surface quality deteriorated by 129% with an increasing volume fraction of alumina microspheres (0.61 μm to 1.4 μm). Burr height reduction of 53% was achieved with cryogenic machining (60 μm) compared to dry machining (130 μm). Overall, compared to dry and wet machining methods, cryogenic drilling can be employed for the machining of AZ31 magnesium syntactic foams to achieve good surface quality and integrity.American University of Sharja
Ultrasound-Mediated Drug Delivery in Cancer Therapy: A Review
No full textThe use of ultrasound as a medical diagnostic tool began in the 1940s. Ever since, the medical applications of ultrasound have included imaging, tumor ablation, and lithotripsy; however, an ever-increasing body of literature demonstrates that ultrasound has potential in other medical applications, including targeted drug delivery. Site-specific drug delivery involves delivering drugs to diseased areas with a high degree of precision, which is particularly advantageous in cancer treatment as it would minimize the adverse side effects experienced by patients. This review addresses the ability of ultrasound to induce localized and controlled drug release from nanocarriers, namely micelles and liposomes, utilizing thermal and/or mechanical effects. The interactions of ultrasound with micelles and liposomes, the effects of the lipid composition, and ultrasound parameters on the release of encapsulated drugs are discussed. In addition, a survey of the literature detailing some in vitro and in vivo ultrasound triggered drug delivery systems is presented
Effect of Aggregate Type and Specimen Configuration on Concrete Compressive Strength
No full textIn this paper, concrete mixes utilizing two sizes of natural aggregate and two sources of lightweight and recycled aggregates were used to investigate the effect of aggregate type and specimen size and shape on the compressive strength of concrete. In addition, samples from ready-mix concrete producers with different strengths were evaluated using standard size cylinders and cubes. Results were obtained on the 7th, 28th, and 90th day. In addition, flexural strength, split tension, and modulus of elasticity were evaluated on the 28th and 90th day. Statistical analyses were conducted to examine the significance of the difference between the compressive strength values for each two mixes using tests of hypotheses. Moreover, other mechanical properties as a function of compressive strength were discussed and compared to those predicated by the American Concrete Institute (ACI) specifications. Results indicate specimen shape has a noticeable effect on the compressive strength as the Cylinder/Cube ratio on the 90th day was ranging between 0.781 and 0.929. The concrete compressive strength and modulus of elasticity were significantly affected by the aggregate type. The flexural strength and split tensile strength were less affected by the aggregate type, which was also confirmed by the values predicted with the ACI equations
Development and Assessment of a Hybrid Solar-Based Multi-Generation System for UAE
No full textA Master of Science thesis in Mechanical Engineering by Mohamed Khaled Ahmed entitled, “Development and Assessment of a Hybrid Solar-Based Multi-Generation System for UAE”, submitted in July 2020. Thesis advisor is Mohamed Gadalla. Soft copy is available (Thesis, Approval Signatures, Completion Certificate, and AUS Archives Consent Form)Over the past few years, major developments were inducted in utilizing solar energy for power generation in rich solar areas, such as the UAE. However, these rich locations are usually arid, and the demand for freshwater is needed. Hence, this thesis aims to develop a solar-based multi-generation system of electrical energy and freshwater in the UAE. The system was designed for a 50 MW electrical load and 8 Million Gallons/day distilled water. The variation of energy consumption throughout the year based on the different weather seasons was studied, and the required power output was optimized to minimize the cost of the system. In this thesis, four different designs were proposed. These designs had different integration combination between the solar technology and the desalination plant. Parabolic trough solar collector and heliostat solar field were the solar sources used, while multi-effect distillation (MED) and reverse osmosis were the desalination plants. The power cycle used in all designs was a Rankine cycle. The mathematical model was performed using System Advisor Model (SAM) and MATLAB. SAM was used to model the solar systems, and then the results obtained were imported into MATLAB to model the remaining subsystems of the design, i.e. steam turbine cycle and the desalination plants. Furthermore, the effects of the operating conditions were investigated to provide guidelines for optimal operation for each system. The designs were compared in terms of their output, solar capacity factor, payback period and total land area. The results showed that the parabolic trough solar collector - steam turbine - MED was the most efficient and effective system. The system produced an average of 41 MW electric power, 13 million gallons/day average distilled water production and had a 94.5 % solar capacity factor, while the levelized payback period was found to be 9.04 years.College of EngineeringDepartment of Mechanical EngineeringMaster of Science in Mechanical Engineering (MSME
Workforce Localization in the Arab Gulf Countries: How Do Organizations Socialize the Members of a Powerful Minority?
No full textThis paper addresses a key social–cultural aspect of sustainability in the Gulf region: Workforce localization (WL). Our research objective is to empirically explore organizational socialization (OS) practices in the context of WL in the United Arab Emirates (UAE), where National Citizens (NCs) are a powerful minority in the workforce. This research adopts a qualitative methodology, using semi-structured interviews with managers in charge of the WL program in 14 organizations in the UAE, across different industrial sectors and ownership. We found five major OS practices: Establishing thorough orientation programs, providing formal training programs (skills, diversity/cultural awareness, supervisor, mentoring and coaching team building), redesigning NCs' jobs and work teams, engaging expatriates in NCs' OS processes, and organizing networking events. All organizations rigorously evaluated the effectiveness of their OS practices. This study contributes to the empirical literature on management OS, WL, and diversity management in a non-western, emerging Arab country. It contributes to theory development on the content of OS practices, showing how a minority can be a powerful group around whom socialization processes are tailored to integrate them fully into the organization. Practically, our findings inform managers of how to adapt their existing OS practices to the specific needs of minority members, and support Gulf Cooperation Council (GCC)-based organizations and policymakers with the design, monitoring, and implementation of WL programs, and with the development of a sustainable workforce
Design of A Theoretical Framework For A Real-Time Fire Evacuation Guidance System
No full textA Master of Science thesis in Engineering Systems Management by Arwa Moamen Abdelfattah Abougharib entitled, “Design of A Theoretical Framework for A Real-Time Fire Evacuation Guidance System”, submitted in July 2020. Thesis advisors is Malick Ndiaye. Soft copy is available (Thesis, Approval Signatures, Completion Certificate, and AUS Archives Consent Form).Despite modern-day advancements in fire protection technologies, stricter fire codes, and more sophisticated modeling of fire propagation and human behavior, fire alarm systems are notably losing the ability to induce evacuative behavior, as people have habituated and grown unresponsive to false alarms. Moreover, people still require active support and guidance during evacuation from a building under fire and are still at risk of using suboptimal routes that could open to untenable conditions. The risk is higher for residential buildings where the majority of all civilian deaths due to fire occur. Therefore, this thesis proposes a smart notification and guidance system with an IoT architecture that can significantly reduce pre-movement and movement times by supporting the decision-making process of evacuees during a fire disaster in a residential building. At the front-end, the system uses crowd, temperature, and smoke sensors to measure environmental conditions, and communicates with occupants through a mobile application. At the back-end, a rule-based optimization approach is used to optimally route evacuees while avoiding the dangers of the fire. The system must also test the recommended egress paths for future tenability by comparing estimated travel times against the Available Safe Egress Time computed by a thermal fire simulator. This thesis develops the theoretical framework and lays the cornerstones for such a system concept through six algorithms, three of which are for pre-optimization processing. The building network problem afterward is framed as an earliest arrival problem and solved using a strongly polynomial earliest arrival transshipment algorithm. As by-products of this work, extensions to the hydraulic model are proposed to account for the effects of smoke and crawling behavior during egress using empirical data.College of EngineeringMultidisciplinary ProgramsMaster of Science in Engineering Systems Management (MSESM
Evaluation of fiber reinforced polymer bars under compression: experiments and finite element simulations
No full textA Master of Science thesis in Civil Engineering by Laith Abdul-Qader Said Al Najmi entitled, “Evaluation of fiber reinforced polymer bars under compression: experiments and finite element simulations”, submitted in November 2020. Thesis advisor is Dr. Farid Abed. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).The behavior of Fiber-reinforced polymers (FRP) bars under compression is not fully understood yet due to the limited research in this area; therefore, American concrete institute (ACI) does not recommend using FRP bars in compression. However, the long-term durability, weathering resistance, and exceptional mechanical properties of FRP bars justify the need for their use in compression members. The main objectives of this study are to evaluate the mechanical properties of Glass FRP (GFRP) and Basalt FRP (BFRP) bars under compression and examine their performance as main longitudinal reinforcement in reinforced concrete columns. In the first part of this research, a series of static tests were conducted on GFRP and BFRP specimens of different diameters. Steel grips filled with epoxy were used at the top and bottom surfaces of the FRP bar to avoid premature failure at the ends and ensure pure compression. The second part of this research numerically investigated the behavior of FRP-RC columns under concentric and eccentric loading using the mechanical properties of FRP bars obtained experimentally. For this purpose, nonlinear finite element models were developed and verified using the experimental results conducted previously at the AUS construction lab. The verified FE models were then utilized to conduct a parametric analysis to simulate the compressive behavior of concrete columns reinforced with GFRP and BFRP bars. Interaction diagrams were also developed based on the FE analysis considering different design parameters such as the cross-section of the column, type and ratio of longitudinal and lateral reinforcement, and loading eccentricities.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE