Engineering Commons^™

A Computational Investigation Into Thermo-Kinetic Parameters Governing The Decomposition Of Bio-Oil Model Compounds, Ali Huseein Aljefri

Thesis/ Dissertation Defenses

Among notable products from thermal degradation of biomass are simple oxygen-containing aromatics. These compounds typically appear in high loads in collected bio-oil derived from biomass. As such, it is important to comprehend the decomposition chemistry of this category of compounds. This thesis takes on board a general approach to report thermo-kinetic parameters that govern decomposition of a selected set of bio-oil model compounds in two distinct systems: firstly radical-derived pathways in the gas phase and secondly thermal degradation in their condensed media. The first is attained through accurate density functional calculations while the second is accomplished through the use of …

Presence Of Atheromatous Plaques And Theirs Effects On The Blood Flow, Belhocine Mostefa Bm, Amrani Hichem Ah, Fedaoui Kamel Dr, Mazouz Hammoudi Mh

Emirates Journal for Engineering Research

The paper utilizes a finite element method to study both the blood flow and atheromatous plaques. Specifically, the COMSOL finite element package is employed to achieve a fluid model. COMSOL is a powerful finite element tool commonly used in various research and industrial domains to study multiphysics problems. The focus of the investigation is on the geometric aspects of the atheromatous plaques. The study considers different forms and arrangements of stenosis, taking into account the irregularities formed by various shapes of the plaques and the resulting flow patterns. The key findings of the research suggest that the pressure and velocity …

A 4-Node Shell Finite Element Based On Assumed Bending And Membrane Strains For Static Analysis Of Plates And Shells, Sifeddine Abderrahmani

Emirates Journal for Engineering Research

In this paper the development of a new rectangular flat shell element is proposed. This element is called SBRPK-SBRIE. This element is used in the numerical analysis of thin structures based on the strain approach with linear elastic behavior. Combining bending and membrane elements yields the proposed element.The strain-based rectangular finite element for the thin plate bending element denoted SBRPK, and the strain-based membrane element denoted SBRIE. Several numerical examples have been conducted to assess the accuracy and reliability of the developed element compared with the theoretical results and other finite elements. Obtained results show its good performance compared to …

Modeling At The Nanometric Scale Of Interfacial Defects Of A Semiconductor Heterostructure In The Isotropic And Anisotropic Cases For The Study Of The Influence Of Stresses, Ahmed Boussaha, Rafik Makhloufi, Rachid Benbouta, Mourad Brioua

Emirates Journal for Engineering Research

This work aims to determine the effect of stresses caused by dislocation networks placed at the interface of a semiconductor heterostructure of the thin GaAs/Si system. In this case, we use a mathematical modeling by Fourier series expansion to numerically simulate the stresses for the two cases of isotropic and anisotropic elasticity in order to predict the mechanical behavior of the heterostructure in the presence of interfacial dislocations while respecting well-defined stress boundary conditions. The elastic stress relaxation is reached for a layer thickness threshold of the GaAs deposit on the Si substrate not exceeding 5 nm.

Resonance Damping Of Lcl Filters Using Capacitor-Current Proportional-Integral Positive Feedback Method For Grid-Integrated Fuel Cell System, Majid Hosseinpour, Amin Kholousi

Emirates Journal for Engineering Research

Nowadays, the use of grid-integrated inverter proton exchange membrane fuel cell (PEMFC) systems is becoming more prevalent due to their efficiency and favorable environmental effects. Switching the grid-connected inverters causes high-frequency harmonics, which are eliminated using LCL filters. These filters are susceptible to instability when their resonant frequency is affected by changes in network impedance. Active damping methods are used to weaken the resonance of LCL filters. However, the grid-connected inverter is prone to be unstable under grid impedance variations due to the negative equivalent resistance resulting by digital control delays. As a solution to this problem, the capacitor-current proportional-integral …

Steady And Transient Study Of Conjugate Heat Transfer In Regenerative Cooled Nozzle, Khaled Bensayah, Khadidja Kamri

Emirates Journal for Engineering Research

The Heat transfer is one of the most serious challenges that exist in a supersonic nozzle flow. The combustion chamber wall and the nozzle are exposed to high-temperature gases during combustion and gas expansion, which can eventually lead to structural failure. This paper reports a computational study of steady and transient conjugate heat transfer in regenerative water cooled nozzle. Numerical computation solved Reynolds-averaged equations based on RSM-Omega turbulence model coupling with solid-phase heat conduction equation and with coolant-phase. The effect of four inlet cooled approach length 0 inch, 6 inch, 12 inch and 18 inch are studied and validated against …

Characterization And Structural Shear Behavior Of Recycled Aggregate Concrete Beams Reinforced With Basalt Fibers And Basalt Bars, Shahrukh Shoaib Ul Haq

Dissertations

Recycling construction waste material offers a sustainable solution to the problem of disposing of concrete construction and demolition waste. The use of basalt fibers (BF) and basalt fiber-reinforced polymer (BFRP) reinforcing bars in concrete structures made of recycled concrete aggregate (RCA) would prolong their service life and reduce the maintenance cost. This research aims to investigate the potential use of BF, RCA, and BFRP reinforcing bars to produce sustainable and steel-free structural concrete. The study consisted of material characterization testing, numerical simulation, and large-scale beam testing.
Material characterization tests were performed on normal-strength concrete (NSC) and high-strength concrete (HSC). The …

Biological Seawater Desalination Using Green Algae And Cyanobacteria, Abdul Mannan Zafar

Dissertations

Water shortage in many coastal parts of the world is reaching alarming situation, including the United Arab Emirates. Urbanization and rapid population growth are generating critical water demands with an increase in per capita consumption. Seawater is usually treated by membrane processes such as Reverse Osmosis (RO). However, this technology is energy intensive and generates excessive brine as a waste. The solution to this problem can be found in natural remediation techniques that can reduce salt concentration from seawater, such as halophytes. A salt-tolerant species can consume Na⁺ and Cl^- ions and increase cellular growth which is termed …

Aerodynamic & Aeroacoustic Performance Of Wind Turbine Blades Featuring Enhanced Flow-Control, Md Zishan Akhter

Dissertations

Wind energy, being one of the cleanest and most sustainable sources, has undergone remarkable growth in recent years due to advancements in aerodynamics and increased power output. The research community is actively pursuing the development of cutting-edge solutions to further optimize wind turbine technology, ensuring its maximum efficiency and revolutionizing the landscape of wind power.
This research aims to design and develop flow-control devices for wind turbine blades, employing both active and passive control mechanisms, namely morphing trailing-edge and slot-profile, respectively. The objective is to enhance wind turbine performance across a wide range of wind speeds. The morphing trailing-edge mechanism …

Experimental Study Of Central And Side Jet With And Without Chevron Nozzle Exit On Gas Turbine Leading Edge Jet Impingement Cooling, Ahmad Yousef Alqasrawi

Theses

This thesis presents a comprehensive investigation into the application of jet impingement cooling on turbines blade leading edge. Gas turbines are extensively utilized in power generation and aerospace industries, where efficient cooling techniques are crucial to enhance the performance and lifespan of turbine blades. The leading edge of a turbine blade is particularly vulnerable to high-temperature exposure and thermal stresses, making it an essential area for effective cooling strategies. Jet impingement cooling is one of the most effective cooling techniques mostly used in the leading edge of rotating and stationary blades. This study aims to explore the performance of jet …

Development Of Guidance, Navigation, And Control Systems For Multi-Spacecraft Assembly In Proximity Operations, Mohammed Ayman Atallah

Theses

This thesis presents the development of Guidance, Navigation, and Control (GNC) algorithms for multi-spacecraft assembly in proximity operations. A 3-DOF mathematical model of spacecraft relative translational motion is derived using the Euler-Lagrange method. Additionally, a 6-DOF mathematical model of spacecraft relative translational and rotational motion is derived using the twistor method, with consideration for the kinematic coupling effect. A new Linear Time-Invariant (LTI) model is developed based on the twistor model, which is utilized in the design of the GNC systems. Both LTI Model Predictive Control (MPC) and Linear Time-Varying (LTV) MPC algorithms are employed to develop Guidance and Control …

Design And Fem Modelling Of Mems Capacitive Accelerometer And Gyroscope For Quadcopter/Uav Applications, Shaikha Rashid Alnaqbi

Theses

This study presents the design, simulation, and analysis of Micro Electromechanical Systems (MEMS) sensors, constituting the principal components of MEMS-based Inertial Measurement Units (IMUs). The main objective of the study is to design, simulate and analyze 3-axis capacitive accelerometer and 3-axis gyroscope. The MEMS-based capacitive accelerometers and gyroscope are analyzed using Ansys Workbench. Modal, Static Structural and harmonic analysis are used to obtain resonant frequencies, deformation/stress and profile of amplitude over a wide range of frequencies. Mechanical sensitivity analysis of the designed accelerometer and gyroscope is performed using the Finite Element Method (FEM). Analytical Equations are developed to calculate mechanical …

Towards Reliable Multi-Path Routing : An Integrated Cooperation Model For Drones, Ibtihel Baddari, Abdelhak Mesbah, Maohamed Amine Riahla

Emirates Journal for Engineering Research

Ad-hoc networks have evolved into a vital wireless communication component by offering an adaptable infrastructure suitable for various scenarios in our increasingly interconnected and mobile world. However, this adaptability also exposes these networks to security challenges, given their dynamic nature, where nodes frequently join and leave. This dynamism is advantageous but presents resource constraints and vulnerability to malicious nodes, impacting data transmission reliability and security.

In this context, this article explores the development of a secure routing protocol for Ad-hoc networks based on a cooperation reinforcement model to reduce the degradation of routing performance. We leverage the reputation of nodes …

Study Of Improved Sorting Weighting Cfar Detectors For Gaussian Environment, Souad Chabbi, Khadidja Belhi, M'Hamed Hamadouche

Emirates Journal for Engineering Research

The goal of this paper is to improve the detection performance and the false alarm regulation of the conventional order statistics Constant False Alarm Rate (OS-CFAR) detectors in a non-homogeneous Gaussian environment. To this end, we design and study the New Sorting Weighting (NSW-) and the Modified Sorting Weighting (MSW-) CFAR detectors. We find closed forms of the detection ( ) and the false alarm ( ) probabilities for both detectors. Moreover, we identify the optimum pairs of weights that maximize the and ensure a constant . Finally, we prove through Monte Carlo simulations that these detectors provide better detection …

Analysis Of Thin Plates In Bending By New Rectangular Strain Based Element., Samira Chichoune, Cherif Rebiai

Emirates Journal for Engineering Research

Abstract

This paper deals with the development of a new simple four node rectangular finite element for bending analysis of thin plates. The displacement s field of this element is based on the assumed functions for the various strains satisfying the compatibility equations. This developed element has three degrees of freedom at each node (two rotations and one translation), and it passed successfully benchmark tests in the case of thin plates without shear locking phenomena. The obtained numerical results using the developed element converge toward both analytical and reference solutions.

Awareness Of Cybersecurity And Its Relationship To Digital Transformation Among Supervisors Of The Education Department In Jazan Region, Maryam Y. Otaif

International Journal for Research in Education

The study aimed to identify the degree of awareness of cybersecurity, and to reveal the reality of digital transformation and the relationship between them from the point of view of the supervisors of the Education Department in the Jazan region. The study followed the descriptive correlative approach, by stratified random sampling (257). a questionnaire was built , The study found that the degree of cybersecurity awareness is high with an arithmetic mean of (3.48), and also degree of awareness of cybersecurity concepts is high, (3,52), and awareness of cybersecurity risks and violations (3.45), and it was found that the total …

Design And Application Of Circular Edge-Fed Linearly Polarized Patch Antenna With Enhanced Bandwidth And Gain For Respiratory Monitoring Systems, Mo’Ath Akram Al Hayek

Theses

This Master’s thesis explores the design and application of a circular edge-fed patch antenna for respiratory monitoring systems. The antenna, fabricated from a thin copper adhesive sheet, demonstrates compatibility with textile materials of low thickness and a relative permittivity of 1.3. Using CST Studio Suite 3D EM simulation software, the antenna’s design was optimized through extensive trials, achieving improved bandwidth and gain. Our findings indicate that the antenna successfully differentiates between various breathing patterns, including slow, normal, and fast breathing rates. The study’s managerial and research implications extend to healthcare, wearable technology sectors, and the broader scientific community. The research …

A Novel Approach For Enhancing Routing In Wireless Sensor Networks Using Aco Algorithm, Sihem Goumiri, Maohamed Amine Riahla, M'Hamed Hamadouche

Emirates Journal for Engineering Research

Wireless Sensors Network (WSN) is an emergent technology that aims to offer innovative capacities. In the last decade, the use of these networks increased in various fields like military, science, and health due to their fast and inexpressive deployment and installation. However, the limited sensor battery lifetime poses many technical challenges and affects essential services like routing. This issue is a hot topic of search, many researchers have proposed various routing protocols aimed at reducing the energy consumption in WSNs. The focus of this work is to investigate the effectiveness of integrating ACO algorithm with routing protocols in WSNs. Moreover, …

Dual-Site Photoplethysmography Sensing For Noninvasive Continuous-Time Blood Pressure Monitoring Using Artificial Neural Network, Anas Mohmmad Rabab’Ah

Theses

Millions of people worldwide struggle from high blood pressure, often known as hypertension, and it is a major health concern that can lead to serious cardiovascular diseases, including heart attacks and many other consequences. Blood pressure monitoring that is reliable and accurate is crucial to the detection and management of hypertension. Although invasive techniques, such as arterial catheterization, are considered to be the most accurate means of evaluating blood pressure, they can be painful, time-consuming and carry a risk of complications.
This thesis presents the development of a real time non-invasive blood pressure monitoring system based on commercially available microcontroller …

A Numerical Investigation Realizing The Flow Structure And Heat Transfer Performance Of The Potential Impinging Jets, Mohammed Sami Uddin Khan

Theses

The demand for improvement in the performance of gas turbines has led to the consideration of flows at increasingly high temperatures, but this introduces challenges in terms of maintaining their structural integrity and preventing overheating. To respond to these challenges, gas turbine manufacturers have turned to internal cooling, and jet impingement provides an effective solution for cooling the leading edge of the blades of gas turbines. In this study, the author numerically simulated the cooling performance of the leading edge of the blades of a gas turbine under constant heat flux by using five configurations of jet impingement: a steady …

Upgrading Biomass To Bio-Oil: Catalytic Hydrodeoxygenation And Pyrolysis Of Vanillin And Anisole Biomass Model Compounds, Ahmad J. Yaghi

Theses

The purpose of this project is to investigate capacity of selected formulations of catalysts toward the hydrodeoxygenation (HDO) of biomass model compounds in the gas phase with the underlying aim to produce hydrocarbon cuts that can be directly used as transportation fuels. The first part of this project is to devoted to illustrate procedures for the synthesis of potent (HDO) catalysts. Synthesized catalysts encompass nickel (Ni), cobalt (Co) and palladium (Pd) supported on zeolite, cerium oxide (CeO₂) or alumina (Al₂O₃). Various characterization techniques such as X-ray Diffraction (XRD), Temperature Programmed Reduction (TPR) were deployed …

Evaluation Of Reliability Indices For Gas Turbines Based On The Johnson Sb Distribution: Towards Practical Development, Elbar Mohamed, Djeddi Ahmed Zohair, Ahmed Hafaifa, Charrak Naas, Abdelhamid Iratni, Ilhami Colak

Emirates Journal for Engineering Research

Recent advancements in computer engineering have provided effective solutions for processing and analyzing complex systems and big data. Consequently, the adjustment and standardization of this data play a crucial role in addressing issues related to the monitoring of industrial systems. In this study, we propose a reliability approach for gas turbines to identify and characterize their degradation using operational data. We introduce a method for adjusting turbine reliability data, which resolves the challenges associated with the nature of these operating data. This enables us to determine a mathematical function that models the relationships between turbine reliability parameters and evaluate the …

A Comprehensive Review Of Dc-Dc Converters For Ev Applications, Shayan Hosseinzad, Amin Mirzaei

Emirates Journal for Engineering Research

DC-DC converters in Electric vehicles (EVs) have the role of interfacing power sources to the DC-link and the DC-link to the required voltage levels for usage of different systems in EVs like DC drive, electric traction, entertainment, safety and etc. Improvement of gain and performance in these converters has a huge impact on the overall performance and future of EVs. So, different configurations have been suggested by many researches. In this paper, bidirectional DC-DC converters (BDCs) are divided into four categories as isolated-soft, isolated-hard, non-isolated-soft and non-isolated-hard depending on the isolation and type of switching. Moreover, the control strategies, comparative …

Numerical Simulation Of Concrete Beams With Discontinuity Regions Reinforced With Nonmetallic Reinforcing Bars, Amena Mohammad Ousama

Theses

Nonmetallic Glass Fiber-Reinforced Polymer (GFRP) reinforcing bars are considered a viable alternative to the conventional steel reinforcement because of their high strength-to-weight ratio and noncorrosive nature. This research aimed to investigate the nonlinear structural behavior of GFRP-reinforced concrete beams with discontinuity regions (D-regions) through numerical analysis. Three-dimensional (3D) numerical models were developed to simulate the nonlinear structural behavior of GFRP-reinforced deep beams with and without web openings. The models adopted realistic constitutive laws that accounted for the nonlinear behavior of the materials used. Predictions of the numerical models were validated against published experimental data. A parametric study was conducted to …

Novel Investigation Of Catalytic Hydrogenation And Oxidation Of 1,3-Butadiene, Ali M. Alabedkhalil

Theses

The hydrogenation of 1,3 Butadiene (BD) is an important industrial process that is generally used to generate butene, which is a key feedstock to produce a variety of chemicals such as polymers, plastic, and synthetic rubber. This process involves reacting BD with hydrogen using different metallic Ni-based catalysts. In this study, Ni/Al₂O₃ and Ni/Nb₂O5 catalysts were used and investigated to perform the hydrogenation reaction because of their commercial availability, effective hydrogenation activity, and affordability compared to Platinum Group Metal (PGM) catalysts.

The catalytic reactions were conducted using a quartz tube reactor between a temperature range …

Thermohydraulic Performance Of 3d Printed Metal Heat Exchanger With Zig-Zag Minichannels, Aysha Rashed Alshamsi

Theses

This work proposes using zig-zag minichannels in heat exchangers for enhancing its performance while operating under balanced (heat capacity ratio of unity) and unbalanced flow (heat capacity ratio of 0.5) conditions for counter flow and parallel flow configurations. The performance of the heat exchangers is quantified in terms of effectiveness and pressure drops and studies are done for hot fluid Reynolds number ranging from 50 to 1500. This work employs a numerical study to investigate the performance of the heat exchanger with zig-zag minichannels.
Simulation is carried out using Fluent module of Ansys Workbench. The model used for simulation consists …

Electrochemical Investigation Of Copperzirconium Based Metallic Glass Cu₅₁Zr₃₀Hf₁₄Ag₅, Tamim Mohammad Ahmad

Theses

This thesis is concerned with the electrochemical investigation of the copper-zirconium

based metallic glass Cu₅₁Zr₃₀Hf₁₄Ag₅. Studying the corrosion behavior of the novel melt-spun metallic glass ribbons contributes to further research on the possibility of building future bio-implants. The objectives of this thesis are to synthesize the metallic glass ribbons which are free from cytotoxic elements using melt spinning technique, verify their amorphous nature using X-ray diffraction method, study the corrosion behavior using Potentiodynamic polarization and Electrochemical Impedance Spectroscopy in different acidic, neutral and basic solutions, and finally examine the surface morphology of …

Intelligent And Explainable Solution To Predict Infant Birthweight And Preterm Birth In The United Arab Emirates, Wasif Khan

Dissertations

Adverse pregnancy outcomes such as Low Birth Weight (LBW) and Preterm birth (PTB) are complex pregnancy challenges that can lead to high perinatal mortality and long-term morbidity for infants. Early prediction of such adverse outcomes can be useful for averting catastrophic outcomes for the mother and her baby. With advances in machine learning (ML)-based algorithms, several models have been proposed for both PTB and LBW predictions. However, the risk factors associated with these outcomes are still unknown, particularly in the United Arab Emirates (UAE). Furthermore, existing ML-based prediction models work in a black-box manner and lack proper interpretations for clinicians, …

Evaluation Of E-Government Information Systems Agility: A Method And Case Study, Soumia Aggoune, Maohamed Amine Riahla

Emirates Journal for Engineering Research

Development of e-government evaluation frameworks began around 2000s. Most of the developed approaches are technologically driven in which they focus on the “E” rather than the “Government”. Moreover, they tend to evaluate tangible measures (such as costs, benefits, etc.) and neglects important intangible measures (such as agility, sustainability, etc.). The state of the art tells that the evaluation of agility within e-government has been proved to be important but complex. However, the importance is due to the increasing need for governments to justify investments, assess impacts and monitor progress in the ever-changing environment. On the other side, the complexity comes …

Integrated Experimental And Dft Study Of Palladium And Nickel Metals Supported On Reducible Metallic Oxides For Selective Hydrogenation Of Alkynes And Dienes Bonds, Toyin Daniel Shittu

Dissertations

This dissertation investigates the capacity of ceria (CeO₂) to serve as a stand-alone reactive catalyst, and to act as catalyst support for different catalyst configurations. Experimental and density functional theory (DFT) approach were used to critically predict and to design ceria-containing catalysts. Ceria owes the catalytic propensity to the ability to undergo switch in the oxidation state from the +4 to +3 states. Motivated by experimental studies involving CeO₂ catalysts, defects CeO₂ surface with an oxygen vacancy (CeO2(111)_Vo) was used to explore the decomposition chemistry of methanethiol based on DFT. The potential formation pathways revealed that …