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Mechanical Properties of Sustainable High Strength High Ductility PE-ECC at Elevated Temperatures
No full textA Master of Science thesis in Civil Engineering by Fardin Mahmoudi entitled, “Mechanical Properties of Sustainable High Strength High Ductility PE-ECC at Elevated Temperatures”, submitted in August 2022. Thesis advisor is Dr. Jamal Abdalla and thesis co-advisor is Dr. Rami Haweeleh. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE
Numerical and sensitivity analyses of various design parameters to maximize performance of a Vortex Tube
No full textIn this study, a series of numerical simulations are performed to investigate the performance of a vortex tube (VT) with various design parameters. The study focuses on six design parameters, mainly, inlet pressure, VT length, VT diameter, number of inlet nozzles, nozzle diameters, and hot outlet pressure. The results indicate that VT performance has a non-monotonic relation with all design parameters and, hence optimum performance can be achieved by conducting response surface methodology (RSM) study. The optimum VT performance is achieved with specific design parameters; for instance, the maximum cooling is achieved with VT length of 194 mm, VT diameter of 14.6 mm, 4 inlet nozzles, nozzle diameter of 1.8 mm, and hot outlet pressure of 60,303 Pa. The results show that energy separation increases at higher inlet pressures until inlet nozzles reach choking condition. Beyond that, the improvement in energy separation is small and VT performance starts deteriorating once shock waves start formulating outside the nozzle.American University of Sharja
Battery Energy Management Techniques for an Electric Vehicle Traction System
No full textThis paper presents two battery energy management (BEM) techniques for an electric vehicle (EV) traction system which incorporates an indirect field-oriented (IFO) induction motor (IM) drive system. The main objective of the proposed BEM techniques is to regulate the IM's speed while minimizing the lithium-ion (Li-ion) battery bank state of charge (SOC) reduction and state of health (SOH) degradation. In contrast to most of the existing work, the proposed BEM techniques operate without any prior knowledge of driving profiles or road information. The first BEM technique incorporates two cascaded fuzzy logic controllers (CSFLC). In CSFLC, the first fuzzy logic controller (FLC) generates the reference current signal for regulating the motor speed, while the second FLC generates a variable gain that limits the current signal variation based on the battery SOC. The second BEM technique is based on model predictive control (MPC) which generates the current signal for the speed regulation. However, this work introduces a new way of tuning the MPC input weight using battery information. It features a fuzzy tuned model predictive controller (FMPC), where an FLC adjusts the input weight in the MPC objective function such that the battery SOC is considered while generating the command current signal. Furthermore, this work utilizes a model-in-loop strategy comprising a Chen and Mora (CM) battery model and the experimentally obtained battery bank power consumption to estimate the increase in battery bank runtime and lifetime. A real-time implementation is carried out on a prototype EV traction system using the New European Drive Cycle (NEDC) and the Supplemental Federal Test Procedure (US06) drive cycles. The experimental results validate that the proposed CSFLC and FMPC BEM techniques exhibit a lower reduction in the battery SOC and SOH degradation, thus prolonging the battery bank runtime and lifetime as compared to the conventional FLC and MPC speed regulators. Further experimentation demonstrates the superiority of the FMPC technique over the CSFLC technique due to the lesser computational burden and higher average energy saving.American University of Sharja
Tethering Natural Capital and Cultural Capital for a More Sustainable Post-COVID-19 World
No full textThe world faced stark challenges during the global pandemic caused by COVID-19. Large forces such as climate change, cultural ethnocentrism and racism, and increasing wealth inequality continue to ripple through communities harming community well-being. While the global pandemic caused by COVID-19 exacerbated these forces, lessons across the globe have been captured that inform the field of community well-being long-after the end of the pandemic. While many scholars have looked to political capital, financial capital, and social capital to tackle these challenges, natural capital and cultural capital have extreme relevance. However, scholarship tends to overlook the inextricable and important links between natural capital and cultural capital in community development and well-being work. These capital forms also inform contemporary understandings of sustainability and environmental justice, especially in the fields of community development and well-being. This perspective article showcases the deep connections between natural capital and social capital through literature review and community cases across the globe. Questions are posed for future research and practice tethering together cultural capital and natural capital when looking to bolster community well-being
Photo-Induced Drug Release from Polymeric Micelles and Liposomes: Phototriggering Mechanisms in Drug-Delivery Systems
No full textChemotherapeutic drugs are highly effective in treating cancer. However, the side effects associated with this treatment lower the quality of life of cancer patients. Smart nanocarriers are able to encapsulate these drugs to deliver them to tumors while reducing their contact with the healthy cells and the subsequent side effects. Upon reaching their target, the release of the encapsulated drugs should be carefully controlled to achieve therapeutic levels at the required time. Light is one of the promising triggering mechanisms used as external stimuli to trigger drug release from the light-responsive nanocarriers. Photo-induced drug release can be achieved at a wide range of wavelengths: UV, visible, and NIR depending on many factors. In this review, photo-induced release mechanisms were summarized, focusing on liposomes and micelles. In general, light-triggering mechanisms are based on one of the following: changing the hydrophobicity of a nanocarrier constituent(s) to make it more soluble, introducing local defects within a nanocarrier (by conformational transformation or photo-cleavage of its lipids/polymers chains) to make it more porous or concentrating heat for thermo-sensitive nanocarriers to release their payload. Several research studies were also presented to explore the potentials and limitations of this promising drug release triggering mechanism.Dana Gas Endowed Chair for Chemical EngineeringAmerican University of SharjahSheikh Hamdan Award for Medical Science
Harmful, Helpful, or Both? A Commentary on Postmodernism and Critical Theories in Community Development Education
No full textIn this relatively informal commentary, I discuss both the potentially helpful and harmful roles that postmodernism and critical theories (e.g., critical race theory, critical sexuality theory) have in academia in general and particularly in community development scholarship and pedagogy. After introducing postmodernism and critical theories as well as some of the common criticisms of these frameworks, I discuss the importance of cultural capital in community development and the ways that postmodernism and critical theories can both protect and maintain cultural capital as well as damage and diminish it. I also discuss the importance of ensuring that students in community development courses understand these frameworks and understand that they are but some of the theories and skills students will need to know to be effective and ethical community development scholars and practitioners. The duty of educators is to ensure that students have the abilities and support to do the hard work of critically evaluating and analyzing all viable approaches to community development work
pH-Responsive Nanocarriers in Cancer Therapy
No full textA number of promising nano-sized particles (nanoparticles) have been developed to conquer the limitations of conventional chemotherapy. One of the most promising methods is stimuli-responsive nanoparticles because they enable the safe delivery of the drugs while controlling their release at the tumor sites. Different intrinsic and extrinsic stimuli can be used to trigger drug release such as temperature, redox, ultrasound, magnetic field, and pH. The intracellular pH of solid tumors is maintained below the extracellular pH. Thus, pH-sensitive nanoparticles are highly efficient in delivering drugs to tumors compared to conventional nanoparticles. This review provides a survey of the different strategies used to develop pH-sensitive nanoparticles used in cancer therapy.Dana Gas Endowed Chair for Chemical EngineeringAmerican University of SharjahSheikh Hamdan Award for Medical SciencesFriends of Cancer Patien
Effect of Frequency on The Dynamic Properties in Resonant Column Testing
No full textA Master of Science thesis in Civil Engineering by Ismail Tarek Ali entitled, “Effect of Frequency on The Dynamic Properties in Resonant Column Testing”, submitted in August 2022. Thesis advisor is Dr. Zahid Khan and thesis co-advisor is Dr. Rana Ahmed. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Dynamic properties of soils are needed to conduct seismic analysis according to building code of UAE. Research on the effect of loading frequency on dynamic properties such as shear wave velocity of geomaterials remains inconclusive mainly due to unquantified biases in available test methods. Resonant column (RC) is a laboratory device that is considered superior to other laboratory and field methods for evaluation of dynamic properties in-spite of testing biases. Effect of frequency on dynamic properties can be masked or unrealistically imposed if known testing biases are not quantified. Contribution from the base of RC device during testing can affect the results either directly or indirectly by affecting the mass polar moment of inertia (MPMI) of the drive plate of RC device. The MPMI of the drive plate is evaluated for every RC using conventional technique in which calibration probes of known dynamic properties are tested. The calculated value of MPMI strongly depend on the stiffness of calibration probes. A new method based on suspension of drive plate instead of mounting on probes is used in this study for evaluation of MPMI. The suspension of drive plate removes connection to base, and contribution of base is minimal. The results of new method are compared with the results of conventional method by testing seven calibration probes and also with selected studies from the literature. The findings of this study agree with previous studies that MPMI from the conventional method has a large scatter with in tested frequencies. Consequently, the variation in the calculated shear wave velocity is also large. The degree of contribution from the base of RC device is found to be comparable with one of the previous study. The effect of base contribution increases with increase in stiffness of calibration probe. The new method on the other hand shows insignificant variation in MPMI of the drive plate within the tested frequencies. The small variations can be attributed to device resolution and measurement errors. The new method is expected to increase the reliability of shear wave velocity by improving the estimate of the MPMI of drive plate.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE
Stabilization of Sandy Soil Against Internal Erosion Using Fly Ash Mixed with Alkali-Activated Binder
No full textA Master of Science thesis in Civil Engineering by Mohammad Suliman Almasaeid entitled, “Stabilization of Sandy Soil Against Internal Erosion Using Fly Ash Mixed with Alkali-Activated Binder”, submitted in November 2022. Thesis advisor is Dr. Mousa Attom. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).Failure due internal erosion is one of the most common crucial failures in hydraulic structures, especially in embankment dams. It is defined as the movement of soil particles due to seepage force. This movement results in defects and a reduction in soil strength causing failure of hydraulic structures. Stabilization of soil is the best approach to avoid such catastrophic failure and prevent a huge loss of lives and properties. Many materials such as cement, lime, and bitumen have been used to stabilize the soil. These materials help in increasing the cohesion, and angle of internal friction and improve other properties of the soil. The main objective of this research is to stabilize sandy soil against internal erosion using fly ash (FA) alone and fly ash mixed with alkali-activated binder. To achieve the objective of this research, well-graded sandy soil was selected and mixed with fly ash alone and fly ash mixed with sodium hydroxide at different percentages. Compaction curves were determined for each percentage, and then specimens from the mix were remolded at 98% relative compaction and optimum moisture content corresponding to the compaction curve value. Hole Erosion Test (HET) was employed to evaluate the rate of erosion of sandy soil mixed with fly ash and fly ash with sodium hydroxide at different curing times (2 days, 7 days, and 28 days). Parameters such as friction factor, coefficient of soil erosion, and critical shear stress were obtained and used to determine the erosion rate index (IHET). It was found that using FA-NaOH significantly reduced internal erosion and increased the erosion rate index and the critical shear of the soil. The addition of 10% fly ash mixed with activated-alkali binder at 7 days curing time stabilized the soil against erosion. At this percentage, the soil was categorized as: “very slow erosion”. However, mixing the sand with fly ash alone has a small or insignificant effect on the internal erosion of the soil, especially at higher percentages of fly ash. The optimum percentage of fly ash alone was found to be 5% at 28 days of curing time.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE
A System For Rating Arterial Facilities With Respect To Pedestrian Health Promoting Features
No full textA Master of Science thesis in Civil Engineering by Haitham Aldahri Abdulatif Badrawi entitled, “A System For Rating Arterial Facilities With Respect To Pedestrian Health Promoting Features”, submitted in May 2022. Thesis advisor is Dr. Ghassan Abu-Lebdeh. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).The built environment, of which transportation systems are an integral component, is a major determinant of public health. Urban arterials, by virtue of their motorized and more sustainable nonmotorized modal functionalities and influences, act as major pathways to socio-economic vibrance and environmental and public health—but only if such targets are incorporated in the various stages of their development and operation. This research presents a system that rates arterial facilities with respect to their inclusion of pedestrian health promoting features (PHPFs). Existing literature shows that pedestrian health may be fostered through 45 physical and operational features of arterial facilities, categorized into seven pathways: air pollution, transport crashes and injuries, noise exposure, physical activity, green and blue spaces, access, and mobility independence. The relative importance of the respective features to pedestrian health was established using the Relative Importance Index (RII) based on direct input from a panel of international transport-public health experts. Based on the relative importance of the different PHPFs, a rating system is developed to assess the level to which the PHPFs are incorporated in the design and/or functionalities of the arterial facilities. The system provides a new perspective on pedestrian facilities along arterials which can guide decisions on creating new facilities or in the process of modifying existing ones. The system was applied to ten arterial facilities selected from various, mixed-use, urban areas in Dubai, United Arab Emirates (UAE), to demonstrate its applicability and use for rating arterial facilities with respect to the level of inclusion of the PHPFs. Facilities are assigned a level of inclusion of PHPFs based on the scores earned. Inclusion levels vary from “A” to “F,” with “A” assigned to facilities with very high inclusion of PHPFs, and “F,” assigned to facilities that do not include PHPFs. Levels between “A” and “F” are assigned, respectively, in proportion to the level of inclusion of PHPFs. The application of the rating system and the results demonstrate its utility to systematically rate arterial facilities with respect to public health and thus the potential to guide their development and operations towards achieving public health goals.College of EngineeringDepartment of Civil EngineeringMaster of Science in Civil Engineering (MSCE