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Manufacturing of Metal Matrix Composites: Optimization of the Powder Metallurgy Process
No full textA poster submitted in ENG 207 taught by Dr. David Prescott for the Fall 2016 semester.Metal Matrix Composites (MMC) is a material made up of combination of metal and ceramics which combines both properties of parent materials. MMC have some significant advantages, such as providing better mechanical strength and resistance to corrosion [1]. They can be produced by different methods ways, but our focus will be on Powder Metallurgy (PM)
Power Characteristics of Selective Buried Oxide MOSFET
No full textA Master of Science thesis in Electrical Engineering by Dana Tariq Younis entitled, "Power Characteristics of Selective Buried Oxide MOSFET," submitted in January 2016. Thesis advisor is Dr. Hasan Al-Nashash. Soft and hard copy available.Power dissipation is an important factor in electronic circuit design due to the decreasing feature size of microelectronic devices, high clock frequencies, and large die size, as well as the growing number of mobile, battery-operated systems. The aim of low-power design for battery-powered devices is thus to increase battery service life while meeting performance requirements. Reducing power dissipation is a design goal for portable and non-portable devices since extreme power dissipation results in increased packaging and cooling costs as well as potential reliability problems. Recently, Silicon On Insulator (SOI) devices have been used that exhibit vertical and horizontal isolation of active devices from the substrate, which leads to higher speed operation and low leakage current. However, SOI devices have serious drawbacks such as the kink effect and self-heating. In this thesis, a new Metal-Oxide Semiconductor Field-Effect-Transistor (MOSFET) structure design is introduced to eliminate the kink effect and self-heating, and to reduce power dissipation while still keeping in consideration the advantages of others such as Bulk and SOI MOSFETs. The new structure is called SELective Buried OXide MOSFET (SELBOX). This transistor combines the advantages of the Bulk and SOI while eliminating the drawbacks. This thesis reviews the various power dissipation reduction methods available in the literature. Next it proposes the structures of Bulk, SOI, and SELBOX for NMOS, PMOS, and CMOS over the first stage followed by a simulation to obtain current-voltage characteristics and static power dissipation. The various MOSFET structures are evaluated in terms of power dissipation. Simulation results will show that the static power dissipation of the Bulk MOS as a single transistor is less than others due to the slow increase in the drain current. Also, SELBOX behavior is very close to Bulk with the advantages of SOI. Simulation results of the CMOS devices show that the static power dissipation of Bulk MOS is very high due to well leakage. SOI has the lowest power dissipation and SELBOX is very close to it. In all cases, SELBOX structure succeeded in reducing power dissipation with a high operating speed, elimination of self-heating, and without a kink effect.College of EngineeringDepartment of Electrical EngineeringMaster of Science in Electrical Engineering (MSEE
Finite Element-Based Parametric Analysis of Mat Foundations
No full textA Master of Science thesis in Civil Engineering by Pouya Partazian entitled, "Finite Element- Based Parametric Analysis of Mat Foundations," submitted in April 2016. Thesis advisor is Dr. Magdi El-Emam and thesis co-advisor is Dr. Sami Tabsh. Soft and hard copy available.Raft or mat foundation is a thick reinforced concrete slab covering the entire contact area of the structure and supporting heavy loads from superstructure to a large area of soil. This type of foundation is employed in scenarios where the column loads are not distributed evenly, level of the structure is lower than the ground water table, and soil is prone to differential settlement. A literature review showed that there is lack of parametric studies on the subject. This study is aimed at using finite element method to investigate the behaviour of mat foundations under gravity loads. The analysis considers mat foundations with different plan dimensions, thicknesses, soil modulus of subgrade reaction, concrete Poisson ratios, modulus of elasticity, panel aspect ratios, number of bays, and load eccentricities. Effect of these design parameters on the maximum and minimum soil bearing pressure below the mat foundation, as well as on the maximum positive and negative bending moment, and shear within the mat will be determined. Result of this study showed that the rigidity of the mat in comparison to the stiffness of the supporting soil is the main parameter that affects the soil bearing pressure and internal forces within the mat. Rigid mats have somewhat uniform soil bearing pressure underneath them, whereas flexible mats have more bearing pressure under the columns than elsewhere. For symmetrically loaded mats subjected to column loads in proportion to their tributary areas, the maximum soil bearing pressure was observed below the corner columns, while the minimum soil pressure occurred within the middle region of central panel. The maximum positive bending moment was found below the interior column closest to the edge, whereas the maximum negative moment was located mid-way between the edge and first interior columns. Location of the maximum shear always happened to be at the face of the edge column nearest to the corner column. Most important parameters that affects the soil bearing pressure, bending moments and shears are mat thickness, soil modulus of subgrade reaction and the distance between columns and eccentricity of the total load with respect to the centroid of the mat.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE
Electric Behavior Modeling and Evaluation of New Lightweight Conductive Concrete
No full textA Master of Science thesis in Electrical Engineering by Bassam Emad Swaked entitled, "Electric Behavior Modeling and Evaluation of New Lightweight Conductive Concrete," submitted in November 2016. Thesis advisor is Dr. Nasser Qaddoumi and thesis co-advisor is Dr. Sherif Yehia. Soft and hard copy available.Concrete mixtures consist of several ingredients such as cement, fine and coarse aggregates, water, and if needed supplementary materials, such as fly ash, silica fume and ground-granulated blast-furnace slag. Such concrete mixtures, considered as conventional concrete, have high electrical resistivity. The addition of electrically conductive admixtures, such as carbon powder and steel fiber, produces conductive concrete mixtures that exhibit improved conductivity for specific applications. Moreover, different types of aggregates can be used to produce concrete mixtures for various applications. Lightweight Aggregate (LWA) has been studied in recent works and has promising applications in the field of civil engineering. It is essential; however, to have a complete analysis of the physical and mechanical properties of any concrete mixture in order to properly evaluate its performance in any intended application. The research efforts, previously conducted on concrete mixtures utilizing LWA, have been focused on the study of the mechanical properties of these mixtures with relation to proportions of other additives. This research focuses on the evaluation of the electrical properties of lightweight conductive concrete mixtures with different constituents. The main objective of the presented investigation is to study the behavior of concrete mixtures containing LWA and the development of an electrical model that can be used to simulate the performance of these mixtures in intended applications. Impedance spectroscopy is utilized to conduct a thorough analysis of the electrical impedance of selected mixtures. The effects of the supplementary and the conductive additives on the impedance of the produced concrete are also studied. These materials are found to change the shapes of the impedance spectra. This is related to their effects on the distributed pores in the mixture.College of EngineeringDepartment of Electrical EngineeringMaster of Science in Electrical Engineering (MSEE
Performance of CI Engine Operating with Hydrogen Supplement Cocombustion with Jojoba Methyl Ester
No full textThe present work experimentally investigates the performance of compression ignition (CI) engine which operates on hydrogen and Jojoba methyl ester (JME). The hydrogen is introduced by enriching air-intake manifold with hydrogen gaseous supplement at the atmospheric condition which is co-combusted in the presence of pilot flame that is initiated by jojoba methyl ester. The engine is supplied with a range of hydrogen-JME fuel mixture proportions to study the effect of hydrogen supplement on combustion and exhaust emissions. Under fixed flow rate of JME, the data shows that hydrogen supplement enhances diesel engine thermal efficiency while reducing specific fuel consumption. The gas emission results shows that as hydrogen supplement increases, NOx emission mildly increases while opacity majorly increases. Hydrogen supplement affects the internal combustion by causing an increase in internal pressure, pressure rise rate and maximum heat release rate. The experiment shows that hydrogen-JME duel fuel smoothly combust in compression ignition engine
Transient Modeling of a New Solar Distillation Unit for Remote Areas
No full textA Master of Science thesis in Mechanical Engineering by Muhammad Mustafa Muhammad Iqbal entitled, "Transient Modeling of a New Solar Distillation Unit for Remote Areas," submitted in December 2016. Thesis advisor is Dr. Mehmet Fatih Orhan and thesis co-advisor is Dr. Hasan Fath. Soft and hard copy available.The concept of lack of fresh water in our daily life is hard to imagine in recent times with its increasing demand. Lack of fresh water supplies has become one of the major current societal concerns, especially for people living in remote areas, where there is limited or no resources of fresh water. Large amount of fresh water is produced using the conventional desalination technologies like thermal and membrane process. The conventional desalination technologies for large water production are Multi Stage Flash (MSF), Multi Effect Desalination (MED), Vapor Compression (VC) and Reverse Osmosis (RO). Big shares of Thermo and/or electrical energies are utilized using these processes. These technologies require high quality operation and maintenance. They require the usage of fossil fuels, which causes negative environmental effects. In order to minimize these effects and especially for remote areas, where the demand of fresh water is less, renewable energy integrated with desalination is the optimum solution. This thesis presents the transient modeling of a novel solar desalination system for remote areas. The new system consists of Solar Still (SS) integrated with multi effect Humidification-Dehumidification (HDH) with built in solar absorber. As the conventional solar still distillation has drawbacks of low specific productivity due to the loss of condensation energy as well as the adverse effect in environment due to brine discharge, the aim is to model and design a solar driven integrated SS-HDH-Absorber desalination unit that can produce the fresh water capacity of 50 Liter with zero brine discharge (ZBD) for a single family use. The main objective is to enhance the unit's water production by utilizing the waste latent heat of condensation of the still and solar absorber thermal energy for additional water production in addition to recovering brine salts as by product. This will lead to produced water cost reduction while maintaining the simplicity of the system operation and maintenance. A numerical code is developed in MATLAB to simulate the integrated system and study the effect of various environmental, design and operational parameters on the unit's productivity.College of EngineeringDepartment of Mechanical EngineeringMaster of Science in Mechanical Engineering (MSME
Experimental Study of Punching Shear Resistance of Synthetic Fiber Reinforced Concrete Interior Slabs
No full textA Master of Science thesis in Civil Engineering by Hazem Mohamed Shaif Jarallah entitled, "Experimental Study of Punching Shear Resistance of Synthetic Fiber Reinforced Concrete Interior Slabs," submitted in September 2016. Thesis advisor is Dr. Mohammad AlHamaydeh. Soft and hard copy available.This study experimentally explores the suitability of Synthetic Fiber-Reinforced Concrete (SNFRC) as a feasible method for improving the punching shear strength of two-way slabs. The investigation involved interior flat slab panels made with two synthetic fiber volumetric percentages, as well as three spacing configurations for the flexural reinforcement. Nine full-scale, 2m*2m*0.15m slabs, are utilized to quantify the SNFRC impact on punching shear strength, toughness and deformation capacity. The nine slabs are divided into three groups of fiber volumetric content: 1.25%, 0.75% and 0%. Each group consists of three flexural steel reinforcement spacing configurations: 16mm-diameter rebars at 60mm, 80mm and 110mm. For SNFRC material characterization, compressive strength and tensile rupture strength are captured via standard 150*150*150mm cubes and 150*150*500mm rectangular prisms, respectively. Material characterization revealed that the introduction of synthetic fibers had a negligible impact on the compressive strength. A reduction of merely 3.4% and 2.3% is associated with adding 1.25% and 0.75% fiber content, respectively. Conversely, the three-point loading test results in 14% and 4% higher rupture tensile strengths associated with 1.25% and 0.75% fiber contents. Moreover, the introduction of synthetic fiber dosages of 1.25% and 0.75% resulted in considerable improvement to the punching shear strength, 36% and 15%, respectively. The greatest effect of the synthetic fiber is found to be on the slab deformation capacity and toughness (quantified as the area under the load-deflection curve). For the 0.75% fibers group, the improvement ranged from 67% to 274% associated with the 60mm the 110mm spacing, respectively. Similarly, for the 1.25% group, the corresponding counterparts have an improvement range of 82% to 324%. For comparison purposes, several analytical predictions for the punching shear strength are made in accordance to the CEB-FIB 2010 Model Code, ACI-318, ACI-544 codes as well as models available in the literature. One particular model is found to best agree with SNFRC slabs when it is re-calibrated in this study. The re-calibration utilized the differences in the steel and synthetic fibers mechanical properties. Namely, Young's modulus, the tensile strength and fiber-concrete bond strength.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE
Ultrasound-induced doxorubicin release from folate-targeted and non-targeted P105 micelles: a modeling study
No full textThe aim of this work is to study the kinetics of ultrasound (70 kHz) – using a kinetic model that takes into account cavitation events and drug re-encapsulation upon the cessation of the acoustic field. The simulation allowed the determination of three parameters α, β and λ that define the release and re-encapsulation behavior of this drug delivery system (DDS). The results showed that the drug release increased with increasing power density, as evidenced by the correlation between α and power density. The micelle re-assembly, quantified by the parameter β, also increased with increasing power density. The parameter λ, which is associated with the initial phase of the release process, showed a constant value regardless of the power density. The significance of these results was discussed. Additionally, a comparison between these parameters in folate-targeted and non-targeted micelles showed statistically significant differences for several power densities examined. A better understanding of the kinetics involved in this DDS is very important for the determination of the optimum ultrasound parameters to be used in future in vitro and in vivo experiments
Access and Application: Addressing the Two Major Problems in Current Business and Peace Research
No full textThe Developing Field of business and peace has largely focused on three research streams: theory, quantitative analyses of perceptions, and qualitative analyses of company actions grounded in other fields such as political science. The theoretical literature has sought to craft theories of change related to private sector enhancement of peace and to properly categorize the types of activities that might, based on prevailing theories in fields such as economics, political science, management, and psychology, help to enhance peace (Forrer and Katsos, 2015; Westermann-Behaylo et al.,2015). This theoretical literature is the core of the business and peace “field”, in that scholars are engaging with and building upon one another’s work. The quantitative literature thus far has largely sought to ascertain the perceptions of managers—primarily at multinational enterprises (MNEs)—operating in conflict and buffer states (Darendeli and Hill, 2015; Oetzel and Getz, 2012). The qualitative literature is often expansive, focusing on unique cases of private sector actors in conflict zones (Katsos and Forrer, 2014; Guaqueta, 2008). It is rarely rooted in or even aware of business and peace theory. Rather, it often is derived from other disciplines with a tangential link to business and peace
Analysis of a hydrogen fuel cell-PV power system for small UAV
No full textThis paper investigates the integration of a hybrid power system for a small unmanned aerial vehicle (UAV). The proposed hybrid power system consists of hydrogen fuel cell, photovoltaic panels and battery. The UAV is modeled to have photovoltaic panels covering the wing area, proton exchange membrane fuel cell and a lithium-polymer battery. A small UAV is used for the study that has low takeoff weight and small dimensions to make the UAV man-portable. Analyses are conducted using data acquired through bench tests of the power systems and simulations. Using drag, lift and weight values, the power required by the UAV is determined. Best test measurements and simulations are conducted for the maximum required power. The flight performance of the UAV improved with the hybrid power system. The UAV endurance increased from 470 min to 970 min. The research study shows the usefulness of hybrid power system for a small UAV. Finally, the paper also establishes the effectiveness of using renewable energy sources for mobile applications