Mechanical Engineering Commons^™

Identifying Challenges Faced By Small And Medium Enterprises (Smes) In The Middle East And North Africa (Mena) Region Through Total Quality Management, Mohamad Atef

Theses and Dissertations

Recently, Small and Medium Enterprises (SMEs) have become recognized as an important driver of global economic growth and innovation. This phenomenon is particularly evident in the MENA region, where small and medium-sized enterprises (SMEs) make a significant contribution to the businesses. SMEs offer significant benefits in terms of job creation, revenue generation, and fostering economic diversity. Although SMEs have a vital contribution in the economy of the MENA region, SMEs face many challenges that hinder their development and long-term viability. Focusing on these challenges is very important for fostering a vibrant and resilient economic environment. The objective of this thesis …

Shape Memory Alloy Capsule Micropump For Drug Delivery Applications, Youssef Mohamed Kotb

Theses and Dissertations

Implantable drug delivery devices have many benefits over traditional drug administration techniques and have attracted a lot of attention in recent years. By delivering the medication directly to the tissue, they enable the use of larger localized concentrations, enhancing the efficacy of the treatment. Passive-release drug delivery systems, one of the various ways to provide medication, are great inventions. However, they cannot dispense the medication on demand since they are nonprogrammable. Therefore, active actuators are more advantageous in delivery applications. Smart material actuators, however, have greatly increased in popularity for manufacturing wearable and implantable micropumps due to their high energy …

Development Of An Electromagnetic System For Wireless Magnetic Manipulation Of Soft Capsule Endoscope For Drug Delivery Applications, Nada Ashraf Hussein Mahmoud

Theses and Dissertations

Wireless capsule endoscopy (WCE) is a remarkable diagnostic device that examines the gastrointestinal (GI) tract. The WCE is a small capsule integrated with a camera that is used to visualize the inner mucosa of the GI tract. WCE has been proven to be the most effective method to diagnose GI diseases and GI cancers. The procedure reduces the discomfort and risk compared to conventional endoscopy methods. However, current WCEs lack the ability to take a biopsy or deliver a drug to a specific location. Those therapeutic functions can be introduced by wirelessly controlled WCEs. This thesis introduces an electromagnetic system …

Improving The Energy Efficiency Of Residential Buildings In Egypt Through Whole Building Simulations, Habiba Aly

Theses and Dissertations

Residential buildings consume around 40% of total electricity consumption in Egypt. This research investigates the energy saving potential of the Green Pyramid Rating system (GPRS) and Tarsheed rating system on the building envelopes of mid-rise middle income residential buildings in Cairo through energy modelling and simulation. The study evaluates the economic feasibility of the recommendations of the two rating systems through Life Cycle Cost (LCC), Simple Payback Period (SPP), Discounted Payback Period (DPP), Net Present Value (NPV), and Internal Rate of Return (IRR) Calculations. This research also aims to develop energy efficiency recommendations to achieve 30% energy savings above the …

Cardiac Active Tension Modeling Via Genetic Algorithm-Optimized Fractional Order Systems, Afnan Khaled Elhamshari

Theses and Dissertations

Developing a computational model to model cardiac activity has been increasingly important in recent decades. Accurate cell-level active tension modeling for cardiomyocytes is critical to understanding cardiac functionality on a patient-specific basis and developing an effective in-silico cardiac model. However, cell-level models in the literature fail to account for viscoelasticity and inter-patient variations in active tension. This research proposes a genetic algorithm-optimized, fractional order system to model cell-level active tension by extending Land’s state-of-the-art model of cardiac contraction. The model features the (left) Caputo derivative of six state variables that identify the mechanistic origins of viscoelasticity in a myocardial cell …

A 3d Imaging-Based Critique Of Wire Arc Additive Manufacturing (Waam) Simulations, Omar Oraby

Theses and Dissertations

Residual stresses play a critical role in the mechanical behavior and structural integrity of engineered components. Understanding and quantifying these stresses are essential for ensuring the reliable performance and durability of materials and structures. Traditionally destructive methods are used that involve sample sectioning and material removal. However, non-destructive methods have gained popularity due to their advantages in preserving the specimen's integrity for further testing and material waste reduction. Among these techniques, Digital Image Correlation (DIC) stands out as a powerful non-contact and full-field measurement approach. DIC captures displacements and strain distributions by analyzing the deformation of speckle patterns on the …

Study Of Vortices Formation In Lateral Intakes Of Pumping Stations, Muhammad Elgindi

Theses and Dissertations

The inefficient design of pumping stations leads to undesirable flow characteristics and the formation of vortices in the sump. These undesirable flow features adversely affect the pumping unit performance and increase the operation and maintenance cost. The aim of this thesis is to assess the ability of the Realizable turbulence model to predict the formation of free-surface and submerged vortices within lateral pumping stations’ intakes. Additionally, the study aims to investigate the effect of the flow ratio and bottom clearance on the flow characteristics and the vortices formation in the sump. Finally, the study introduces an assessment of curtain walls …

Borophene And Graphene For Non-Enzymatic Biosensor- Ab-Initio Study, Omar A. Ismail

Theses and Dissertations

Non-enzymatic glucose sensing holds promise to overcome limitations associated with glucose oxidase, such as oxygen dependence and short shelf life. This study explores the potential sensing capabilities of borophene and graphene through direct interaction with various compounds, including β-glucose, uric acid, ascorbic acid, fructose, and acetaminophen. Using Density Functional Theory (DFT), we calculated binding energies and the respective Density of States (DOS) for these adsorbates on both graphene and borophene surfaces. Preliminary results suggest that borophene might exhibit nearly twice the affinity for β-glucose compared to graphene. Moreover, the calculated Density of States reveals distinct distortions in the electronic states …

Fabrication & Characterization Of Hybrid Piezoelectric/Triboelectric Nanocomposite Nanogenerators Via Fusion Deposition Modeling, Khaled El Toukhy

Theses and Dissertations

This thesis aims to discuss the potential of using piezoelectric and triboelectric nanogenerators (PTENGs) for energy harvesting, particularly in the sportswear industry. PTENG's main advantage is that it offers good flexibility making it suitable for high-strain applications. The piezoelectric effect is induced by embedding piezoelectric nanofillers into one of the two triboelectric layers. PTENGs can generate both piezoelectric and triboelectric signals when strained resulting in an enhanced output compared to regular piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs). TPU was adopted as the matrix for PTENGs advantageous due to their flexibility, low electrical resistivity, and compatibility with additive manufacturing techniques. …

Additive Manufacturing Of Stretchable Strain Sensors: Fabrication, Optimization And Application, John Nady Shihat Bastawrous

Theses and Dissertations

In this project, a novel strain sensor design is fabricated employing different additive manufacturing techniques. The spring sensor's primary material is PLA-Like resin with a nanocomposite encapsulation layer as the functional material. The main principle of Straining the sensors results in a change in resistivity as the distances among the conductive carbon particles change according to the strain applied.

Sensor fabrication consists of two parts: spring manufacturing and development of nanocomposite encapsulation The nanocomposite matrix is developed through the dispersion of Graphene and Carbon nanotubes in Thermoplastic Polyurethane through sonication and magnetic hotplate stirring. While the spring itself is manufactured …

Computational Study On The Acoustic Footprint Of Stenosis In Larger Arteries, Ahmed Abdelnabi

Theses and Dissertations

We identify a new (acoustic) frequency-stenosis relations whose frequencies fall within the recommended auscultation threshold for stethoscopy (< 120 Hz) in this study. We demonstrate that these relations can be used to extend the application of phonoangiography (the measurement of the degree of stenosis from bruits) to stethoscopes that are broadly available. The First relationship is successfully identified using an analysis limited to the acoustic signature of the von Karman vortex street, which we automatically isolate using a metric based on an area-weighted average of the Q-criteria for the post-stenotic region. Specifically, we conduct LES-CFD simulations on simplified 2D internal flow geometries that represent blood vessels with varying degrees of stenosis. Then, using the Ffowcs Williams-Hawkings (FW-H) equation, we extract their emitted acoustic signals, which we subtract from a pure signal (stenosis-free) at the same heart rate. Next, we transform this differential signal to the frequency domain and meticulously classify its acoustic signatures according to six stenosis-invariant flow phases of a cardiac cycle. Using our Q-criterion-based metric, we then automatically restrict our acoustic analysis to the noises emitted by the von Karman vortex street (phase 4). Our analysis of its acoustic signature demonstrates a strong linear relationship between the degree of steno- sis and its dominant frequency, which differs significantly from the break frequency and heart rate (previously identified dominant frequencies). For the Second relationship, we develop a frequency-stenosis scaling law for particularly supravalvular aortic stenosis that falls within the preferred frequency range (30-120 Hz) for echocardiography. We expand to 3D patient specific geometry using Simulia’s Living Heart Human Model (LHHM), which has an anatomically accurate aorta geometry. This LHHM geometry is modified with stenoses ranging from 30 to 80 percent (moderate to severe). For physiologically consistent hemodynamic boundary conditions, we expand the study to employ the Windkessel model, which has been implemented on Fluent using UDF. We demonstrate that physiological boundary conditions reduce simulation time significantly compared to static boundary conditions. The FW-H model extracted the flow-generated acoustic signal of the stenotic geometries and analysed it at clinically relevant receiver locations. A preferred receiver location consistent with clinical practise is determined, and a correlation between the degree of stenosis and the prevalent acoustic frequency (within the frequency range of 70-120 Hz) is established. The obtained second scaling law is shown to be clinically reliable in assessing stenotic severity. Future research will investigate incorporating the vibroacoustic role of adjacent organs and tissue to expand the clinical applicability of our findings. Expansion of clinical and numerical datasets will be pursued in future research to enhance the reliability of our scaling law, possibly by leveraging much-needed ML-based acceleration schemes.

Biogas Combustion Characteristics In A Concentric Flow Slot Burner: Effects Of Co2 Concentration On Stability And Flame Structure, Maged Kiriakos

Theses and Dissertations

Biogas combustion is affected by the concentration of carbon dioxide. The successful applications of Biogas as a sustainable renewable alternative fuel produced from waste depend on its combustion stability, heat release, and pollution level. The aim of the current study is to apply new combustion technology and study the stability and combustion characteristics of natural gas with different percentages of carbon dioxide from 0 to 40% simulating biogas fuel. The stability characteristics and the temperature profiles of turbulent planar flames at different levels mixture inhomogeneity are investigated and presented in this work. The flames are created in a newly developed …

Accurate Evaluation Of The Direction-Dependent Mechanical Properties Of Ideal Single Crystals: A Comparative Ab Initio Study, Jaylan Ali Elhalawani

Theses and Dissertations

The mechanical properties of a single crystal or a grain in a polycrystalline material are highly dependent on the direction of the applied load. Key properties of interest are the Young’s modulus and the Poisson ratio in the small strain limit, and the ideal tensile strength in the large strain regime. Prior atomistic computations of these properties interchangeably used two approaches. In one approach the stress-strain response is explicitly calculated via a numerical tensile test experiment. In the second approach the second order single crystal elastic constants are computed via small deformations and then used in analytical equations to derive …

Estimating Solar Energy Production In Urban Areas For Electric Vehicles, Shaimaa Ahmed

Theses and Dissertations

Cities have a high potential for solar energy from PVs installed on buildings' rooftops. There is an increased demand for solar energy in cities to reduce the negative effect of climate change. The thesis investigates solar energy potential in urban areas. It tries to determine how to detect and identify available rooftop areas, how to calculate suitable ones after excluding the effects of the shade, and the estimated energy generated from PVs. Geographic Information Sciences (GIS) and Remote Sensing (RS) are used in solar city planning. The goal of this research is to assess available and suitable rooftops areas using …

Multi-Objective Optimization On Dimensional Accuracy, Edge And Surface Quality Of 3d-Printed Parts By Fused Deposition Modelling, Islam Hamdy Salem

Theses and Dissertations

Fused Deposition Modelling (FDM) is one of most common additive manufacturing (AM) techniques used in manufacturing field. It has been increasingly used because of its low cost and simplicity. Although FDM can save time through eliminating pre-processing tooling-up to produce the end-user product, still a better final product quality, like mechanical properties, dimensional accuracy and surface finish, is needed. This thesis addresses the maximization of involved printing parameters in one reliable model. Hence, a wider investigation is conducted in this research via experimental work in order to obtain a comprehensive model that involves and relates more parameters in a single …

Energy Planning Model Design For Forecasting The Final Energy Consumption Using Artificial Neural Networks, Haidy Eissa

Theses and Dissertations

“Energy Trilemma” has recently received an increasing concern among policy makers. The trilemma conceptual framework is based on three main dimensions: environmental sustainability, energy equity, and energy security. Energy security reflects a nation’s capability to meet current and future energy demand. Rational energy planning is thus a fundamental aspect to articulate energy policies. The energy system is huge and complex, accordingly in order to guarantee the availability of energy supply, it is necessary to implement strategies on the consumption side. Energy modeling is a tool that helps policy makers and researchers understand the fluctuations in the energy system. Over the …

Nylon6-Montmorillonite Nanocomposites: Synthesis, Structure And Properties, Ahmed Mahmoud Abdel Gawad

Archived Theses and Dissertations

Layered silicate clays have been used for decades as filler materials to enhance mechanical and thermal properties of polymers. Recently, efforts have focused on separating the layers of the clay with the purpose of forming clay-polymer nanocomposites. Investigations have been addressing the enhancement of mechanical and thermal properties of these materials. In this study, 5wt% of commercial montmorillonite clay (Cloisite Na+) and organically-modified montmorillonite (OMMT) clays (Cloisite 15A and Cloisite 30B) were compounded with nylon6. Nylon6/layered silicate nanocomposites were fabricated using melt compounding and solution compounding techniques. Nanoindentation, x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), melt flow index (MFI) and …

Life Cycle Climate Performance Assessment For R1234yf As A Low Gwp Drop-In Alternative For R134a In Domestic Refrigerators, Mohamed Ragab Senosey Khaled Zain

Theses and Dissertations

Aligning with the global movements towards mitigating CO2 emissions and regulations to phase out HFC refrigerants, many low GWP refrigerants are being tested and proposed as fourth-generation refrigerants. R1234yf is a refrigerant with a GWP of less than one and has a high potential to replace R134a, which has a GWP of 1300, and it is the most commonly used refrigerant in domestic refrigerators. In this study, an energy performance evaluation and a life cycle climate performance assessment for R1234yf were conducted and compared to those of R134a based on a baseline domestic defrost refrigerators. Four different charges of R1234yf …

Fluid-Structure Interaction Of Nrel 5-Mw Wind Turbine, Mohamed Sayed Elkady Abd-Elhay

Theses and Dissertations

Wind energy is considered one of the major sources of renewable energy. Nowadays, wind turbine blades could exceed 100 m to maximize the generated power and minimize produced energy cost. Due to the enormous size of the wind turbines, the blades are subjected to failure by aerodynamics loads or instability issues. Also, the gravitational and centrifugal loads affect the wind turbine design because of the huge mass of the blades. Accordingly, wind turbine simulation became efficient in blade design to reduce the cost of its manufacturing. The fluid-structure interaction (FSI) is considered an effective way to study the turbine's behavior …

A Self-Tunable Piezoelectric Energy Harvester, Ashraf Hussein

Theses and Dissertations

In this study, a new technique to harvest energy using inertial vibration energy harvesters is introduced. A triple-layer piezoelectric beam with a self-tunable frequency was developed in order to respond to variable-frequency excitations, thereby maintaining the beam in a state of resonance for maximum power output. The tuning mechanism managed to change the natural frequency of the beam in the range of 2.27 ���� to 6.25 ����. In this case, the output voltage could be raised from 12�� to 23��.

A mathematical model was developed to investigate the natural frequency, the output voltage, and the output power of the beam …

An Exact Algorithm For Solving The Set Partitioning Problem, Ahmed Mohamed Badr

Archived Theses and Dissertations

No abstract provided.

Analysis Of Folded Core Sandwich Structures, Waleed Ahmed Ibrahim Mahmoud

Archived Theses and Dissertations

No abstract provided.

Production And Characterization Of Foam Glass From Container Glass Waste, Dina Mohamed Abdel Alim

Archived Theses and Dissertations

No abstract provided.

Analysis Of The Flow Through A Francis' Turbine Runner Using Computational Fluid Dynamics, William Anthony

Archived Theses and Dissertations

This study investigates the fluid flow through the runner of an exceptionally low specific speed Francis’ turbine using computational fluid dynamics (CFD) to predict some performance characteristic of the runner, and to determine the effect of cavitation on the flow features within the turbine. It employs FLUENT CFD codes for the analysis. The study was carried out under steady conditions in two- dimensional analysis, primarily using the RNG k-ε turbulence model. It is mainly on single phase analysis; however a single case of two-phase cavitation modeling was performed in order to evaluate cavitation effects. The hydraulic losses were much dependent …

Applications Of Data Mining For Educational Decision Support, Mohamed Nabil Essam El-Din Ahmed El-Refai Khamis

Archived Theses and Dissertations

No abstract provided.

Controlling The Processing Parameters For Consolidation Of A1-2124 Micro And Nanopowders Into Bulk Nanostructured Material By Combined Hot Compaction - Intense Plastic Straining, Ahmad Mar Wagih Sadek

Archived Theses and Dissertations

No abstract provided.

Design And Optimization Of Input Shapers For Liquid Slosh Suppression, Ameen Aboel Hassan

Archived Theses and Dissertations

The need for fast maneuvering and accurate positioning of flexible structures poses a control challenge. The flexibility inherent in these lightly damped systems creates large residual vibrations in response to fast disturbances. Several control approaches have been proposed to tackle this class of problems, of which the input shaping technique seems quite appealing. While input shaping has been widely investigated to attenuate residual vibrations in flexible structures, less attention was granted to expand its viability in further applications. It is therefore the aim of this work to develop a methodology for applying input shaping techniques to suppress sloshing effects in …

The Effect Of Cold Work On The Mechanical Behavior Of Niti Shape Memory Alloys, Mohamed Elwi Mitwally

Archived Theses and Dissertations

No abstract provided.

Vibration- Based Damage Detection Using Damage Location Vectors, Khaled Faizallah Mostafa

Archived Theses and Dissertations

No abstract provided.

Effect Of Different Additives On Properties Of Virgin Pp/Recycled Pp To Substitute Pc, Myriam Nabil Raouf Demian

Archived Theses and Dissertations

The use of polymers in many products have increased tremendously in the past few years leading to an increase in the amount of plastic waste generated, which in return became a huge problem. There are several ways to handle these wastes including; landfilling, chemical recycling, mechanical recycling and incineration. In Egypt mechanical recycling takes place in order to re-use these polymers in new products. The concern of this thesis is to try to find solution for some of the unused wastes by mechanically recycling them. The research aims to modify the properties of one of the most available polymers which …