Materials Science and Engineering Commons^™

Material Selection And Optimization To Mitigate 316l Stainless Steel Corrosion In A Condensate Stabilizer, Afif Saif Nasser Harhara

Theses

The United Arab Emirates (UAE) is one of the key players of the oil and gas industry of the world; with oil reserves estimated at 9% of the total world reserves, the petroleum industry is considered to be the backbone of the economy.

In one of the gas processing facilities in Abu Dhabi, UAE; a case of material failure occurred in the fractionating column twice in a cycle of less than 2 years. The materials used for the internals of the column was stainless steel 316L. The different types of stainless steel corrosion were studied with emphasis on the suspected …

Effects Of Natural And Accelerated Weathering On The Performance Of Locally Manufactured Polymer-Modified Bituminous Waterproofing Membranes, Rauda Ali Saeed Al Saadi

Theses

As in most industrial sectors, today there is a growing preoccupation about product quality. Since waterproofing systems are intended to have the longest possible service life, one of the most critical quality features is their aging performance. As a result, the importance of aging tests is steadily growing, especially in the hot-dry climate zones.

Polymer-modified bituminous waterproofing membranes are normally exposed to solar radiation and various weathering conditions when used in residential and commercial buildings. They are attacked and deteriorated to some degree by environmental factors such as heat, radiation, especially ultraviolet, moisture and gases. The weathering (aging) consequences commonly …

Preparation And Characterization Of (Gesbte)) Semiconductors For Phase-Change Optical Storage, Hessa Ali Humeid Al-Shamisi

Theses

In the last decade, the phase change optical recording based upon chalcogenide glasses has advanced remarkably at full-scale commercial applications in the form of rewritable compact disks (CD-RWs). The principle of phase-change optical recording is based on a thermally induced reversible transformation between amorphous and crystalline phases. The search for recording materials possessing fast crystallization rate and long data retention has been pursued. Research results have revealed that Ge-Sb-Te compounds exhibit fast crystallization, which has been explained in terms of their single-phase structure.

In the present work, electrical properties of Ge-Sb-Te thin films using Impedance Spectroscopy, Current-Voltage, and Capacitance-Voltage techniques …

An Investigation On The Corrosion Resistance And Stress Corrosion Cracking Of Ductile Ni-Resist Cast Irons In Desalination Plants., Yahya Abdulla Alzafin

Theses

Two cases of stress corrosion cracking failures of brine pumps casings have been reported. These pumps are installed in two desalination plants located on the coast of Arabian Gulf in UAE. The materials of construction of failed parts are Ni-Resist Ductile Irons (NDI) and the environment is brine, which is concentrated seawater. Two brands of pumps had different lives to total failure; one lived 18 years while the other lasted only 5 years. The failed parts of former pumps were made out of NDI material as per American standard ASTM A439 D2 (designated D material) whereas those of latter pumps …

Experimental Investigation And Numerical Modeling Of Hybrid Glass/Carbon Frp Section Combined With Concrete Slab, Stephen Craig Raynor

Theses

No abstract provided.

The Effect Of The Size Of Pinning Centres On The Critical Current Density In High-Temperature Superconductors, Salama Bakhit Sowaidan Al-Neaimi

Theses

Superconductor materials that have no resistance to the flow of electricity are one of the last great frontiers of scientific discovery.

Superconductivity in these materials occurs particularly in the copper-oxide (CuO₂) planes. However, since these materials are type-II superconductors, magnetic fields can penetrate these materials in quantized amounts of flux called vortices without completely destroying superconductivity, but producing some resistance, due to vortex motion. In order to overcome the resistance problem, vortices must be pinned to prevent their motion and hence eliminate the resistance.

In this work study we have performed extensive numerical simulations to study the effect …

Investigation Of The Band Structures And Optical Properties Of Super Lattices, Sheikha Ahmed Awad Alnaeme

Theses

Group III nitrides are highly attractive materials because of their great potential for the development of optoelectronic devices in short wavelength, semiconductor lasers and optical light-emitters and detectors. GaN, AlN and InN are considered as the most important compounds in this class of materials. In this work, we present a theoretical investigation of the electronic properties (band structure, density of state and contour maps of the charge density distribution) and optical properties (refractive index, absorption and dielectric constants). Also, we investigate the band structures and optical properties of AlN/GaN and InN/GaN super lattices. A full-potential linearized plane-wave (FPLAPW) method is …

Characterization Of Thermally Diffused Bordie Layers On Aisi 1018 Steel : Residual Stresses (By Synchrotron Radiation) And Microhardness, Joel A. Payne

Theses

Boronization is a thermal diffusion process in which needle like boride layers are formed at the surface of the metallic substrate. The boride coatings formed by the diffusion process have high hardness and strong ware and corrosion resistance. In order for coatings of this nature to be industrially successful, their service life should be long and characterization should be extensive. Measuring the residual stresses of the coatings caters to each of these aspects.

In this study, AISI 1018 steel samples were boronized by a powder-pack process for four hours at 850°C in an argon atmosphere. Characterization techniques included coating thickness, …

Submicron Patterning Using Laser Interference Lithography, Luigi Pollara Verdoni

Theses

In this thesis, the theory, fabrication protocol, and initial results of an alternative nanopatterning technique called Interferometric Lithography (IL) are presented. Comprised of the identical process attributes of traditional projection photolithography, IL mirrors the wafer preparation and development procedures of our existing clean room capabilities. The main departure is solely in means of pattern delineation. IL is a "mask less" technique that employs the interference fringe pattern of two coherent beams, and can therefore be generated with a commercial laser. Due to its simplicity, Interferometric Lithography provides an attractive supplement to existing methods of nano-patterning.

Utilizing a 325 nm HeCd …

The Effect Of Sample Size And Ground Granulated Blast-Furnace Slag On Hydration Temperature In Hot Climates, Mariam Eissa Saeed Al-Harrasi

Theses

Heat of hydration of Portland cement mixes is of great importance to civil engineers. While there is great deal of work being carried out on the hydration temperature of OPC-slag mixes, there is a lack in the literature of research work on the effect of such materials in real hot climates. The current research examines the influence of ground granulated blast-furnace slag (ggbs) as a partial cement replacement on temperature evolution during hydration in winter and summer in AI-Ain (interior region of the United Arab Emirates). Evolution of temperature inside the concrete was recorded by the aid of a Labview …

Electrochemical Corrosion Testing Of Boronized And Unboronized Steels, Kranthi K. Pallegar

Theses

Boronizing is a thermo-chemical surface coating technique with which surface properties of materials are enhanced substantially. One of these properties is corrosion resistance. Corrosion resistance testing has been performed in many ways right from the traditional weight loss methods to the latest electrochemical techniques. These electrochemical techniques are more reliable and less time consuming and hence are widely accepted for corrosion testing in the industry.

In the present work, direct current (D.C) corrosion testing studies of both boronized and unboronized steels have been discussed. Three types of steels, AISI 1018, AISI 4340 and AISI 304 stainless steel, were considered for …

Boron Induced Surface Modification Of Transition Metals, Raghasudha Vangaveti

Theses

Boronizing is a thermo-chemical surface treatment of metals in which boron atoms diffuse into the metal substrate and form hard metallic borides. As a result of boronizing, several properties such as hardness, wear resistance, corrosion resistance, and high temperature oxidation resistance improve which make the metal substrate more suitable for industrial applications. These boronized parts are used in many industrial applications like ingot moulds, crucibles, biomedical implants, die-casting moulds, magnetic head applications, drawing dies etc.

The objective of this work was to investigate the influence of boronizing on the properties of transition metals. Three transition metals, tantalum, niobium and tungsten …

Microwave Modeling And Characterization Of High-Tc Superconducting Thin Films, Thamer Mousa Badarneh

Theses

Because of the high critical temperature (Tc) that the new superconductors can reach, thin films can be used in a number of technological applications. One of the major applications of thin films is in the microwave devices, where superconducting strips are used as resonators, filters, delay lines, etc. The importance of the superconductors resides in the low losses incurred during the transmission along the strip. For example, the surface resistance of a high-Tc superconductor is at least one order of magnitude less than a similar one made of ordinary conductors. Because of this advantage, there is an increase in the …

Fabrication Of Array Microstructures By Localized Electro-Deposition, Nidal Khalaf Alshwawreh

Theses

Localized Electro-Deposition (LED) is now highly receiving scientists and researchers attention for its advantages over conventional fabrication techniques. These advantages include simplicity of the setup thus reducing the overall fabrication cost, capability of producing 2D and 3D high aspect ratio microstructures and its ability to fabricate microstructures from various raw materials. Efforts now are taking place in order to standardize the fabrication by LED to develop a commercial setup that is capable of producing complex microstructures which, in tum, can be integrated in different applications including microelectronics, microelectrochemical systems (MEMS) and sensors applications. The standardization process is performed by studying …

Synthesis And Solution Characterization Of Water-Soluble Polyacrylamide And Its Applications In Oil Industries, Ghuwaya Humaid Alnuaimi

Theses

No abstract provided.

Investigations Of The Kinetics Of Liquid Droplets On Soil Substrates Using A Novel Approach: Contact Ratio, Abdelhafiz “Moh’D Adnan” Herbawi

Theses

In view of young’s equation, in which the contact angle “ϑ” and the liquid surface tension γ_lv are the only measurable parameters, the contact angle has been widely conceived as a thermodynamic quantity. Accordingly “ϑ” has been the main focus of most theoretical and experimental investigations. The rate of change in the contact angle has been commonly used as the relevant parameter of spreading dynamics in spite of difficulties associated with contact angle measurements that are well recognized in the literature. Considering that the velocity of the contact line is the pertinent quantity for spreading, it is therefore reasonable …

Microwave Processing Of Fiber Reinforced Composites (Optimization Of Glass Reinforced Epoxy Curing Process), Mohamed Osama Ali

Theses

Microwave curing of polymer matrix composites has proven to be an attractive substitute for conventional thermal curing. Industrial applications are currently developed including telecommunications, aerospace, food industry, enhancement concrete setting, composites manufacturing, and many others. Many universities and research centers around the globe are endeavoring to make use of this technology to the most. Common research objectives include homogeneity of the cure, the acceleration of cure kinetics, cure reaction mechanism, and enhancement of mechanical properties. In order to efficiently utilize this form of energy, precise control over power, temperature, and time were applied to achieve set goals: reduce cure time …

Effect Of Bond Thickness On Lifetime Of Adhesive Joints, Ehab Mohammed El-Said El-Refaai Shehab

Theses

The aim of this research was to study the effect of bond thickness on the fracture energy and the lifetime of an adhesively bonded system and develop a model to predict the lifetime of adhesive joints. An approach based on fracture mechanics was employed to assess aluminum/epoxy bond lifetime. An experimental investigation was carried out using double cantilever beam (DCB) specimens with various bond thicknesses under mode 1.

This study describes an approach to predict the rate of crack propagation using Paris' power law. The approach used elevated temperatures to accelerate the crack propagation under constant loads. The elevated temperatures …

Ductile Crack Growth Emanating From Sharp Notes In A Low Alloy Steel, Aladdin I. Abu-Assi

Theses

Stable crack growth behavior emanating from a sharp notch is investigated. Material chosen for tests was EN 34 NiCrMo6 low alloy steel (akin to 4340/4330). Tests were carried out on CT specimens for various angles and ratios to obtain load vs, load-line displacement, Ρ-Δ_LL, curves. Experimental results were analyzed. A normalization approach of Ρ-Δ_{LL curves has been attempted and all experimental curves were represented as a single characteristic curve. Such approach has been also applied on experimental data available from other experimental investigations and results were encouraging, as it may address transferability issue. Fracture surfaces were …}

Investigation Of Epoxy Resin Spreading On Glass Surfaces, Haneen Nemer Al-Dahdooh

Theses

The spreading of a small epoxy resin droplet (l.5tL) on a glass surface was examined with the objective of developing a new type of hydrophobic polymer coated glass which has the ability to reduce heat gain inside a building. The study covered three main aspects; the spreading kinetics of epoxy resin on a glass surface, the hydophopicity of the developed polymer-coated glass surface, and the reduction of solar radiation of this surface, As wettability and spreading phenomena arc a fundamental prerequisite for coating, the spreading kinetics of different curing agent concentrations (15:200, 18:200, 21:200) of epoxy resin on the glass …

Thermal And Mechanical Properties Of Polyethylene-Polypropylene Blends, Rania Omar Akkad

Theses

The thermal and mechanical characteristics of thermally treated and untreated pure polyethylene (PE), pure polypropylene (PP) and their blends were investigated. Injection-moulded samples containing 100:00,75:25,50:50,25:75 and 00:100 weight percentage of PE:PP, were prepared and thermally treated at 100°C for 0, 2, 4, 7, 14 days. The treated samples were subjected to differential scanning calorimetry (DSC), thermogravimetry (TG & DTG), infrared spectral analysis (IR) and tensile tests in order to study the effect of thermal treatment and blending ratios on their thermal and mechanical properties. The results indicate that addition of PE causes the melting temperature (T_m) of PP …

Ab Initio Calculation Of Electronic And Optical Properties Of Beryllium Chalcogenides (Bes, Bese, And Bete) Under The Effect Of Pressure, Aisha Ali Saif Bannan Al-Kaabi

Theses

There are several methods for materials simulation. Ab initio or first principles methods are used to solve the quantum mechanical equation which govern the behavior of a system. Ab initio calculation of the optical and electronic properties of solids is fundamental in solid state physics. APW+lo is used to examine different properties of BeS, BeSe and BeTe. Beryllium compounds show different features in structure under different pressures, and they also show a phase transition from Zinc blende to Hexagonal transitions in II-VI semiconductors. Little is known about the ground state properties of Beryllium Chalcogenides. The aim of this work is …

Stabilization Of Desert Sand Using Water-Borne Polymers, Shihab Wagiealla Abdalla Mohamed

Theses

Soil stabilization is one of the various applications that have benefited from the advances in polymeric materials. In this research, three water-borne polymeric emulsions with different chemical and physical properties were tested as stabilizers for sandy soil.

This study is divided into three parts. In the first part, the performance of the three emulsions in reducing the hydraulic conductivity and improving the mechanical properties of the sand was investigated. Specimens with polymer contents of up to 2 wt. % were prepared using two preparation methods, mixing and spraying. Both types of specimens exhibited a significant improvement in the studied properties. …

Surface Treatment Of Ferrous Alloys With Boron, Naruemon Suwattananont

Theses

Boronizing is a thermo-chemical surface hardening treatment in which boron atoms diffused into the metal substrate form the metallic boride layer, providing high hardness, corrosion resistance, and 3-10 times increasing service life. This type of surface treatment is widely used in many applications.

The purpose of this work was to investigate the structures and properties of boronized ferrous alloys. Three types of steels, AISI 1018 (plain low carbon steel), AISI 4340 (high strength alloy steel), and AISI 304 (austenitic stainless steel), were used for this study. The boronized AISI 1018 and AISI 4340 demonstrated the saw-tooth structure with average 75-76 …

Crystallization Kinetics Study Of The Glasses In Se–Te System, Fareed Abdul Raheem Al-Gheyath

Theses

The aim of the present work is to study the crystallization kinetics of some chalcogenide glassy alloys in the Selenium-Tellurium system. Four glassy systems have been prepared: Se₈₀Te_20-xSb_x (x= 0, 4, 6, 8, and 10); Se₇₀Te_30-xSb_x (x= 2, 6, 8, and 10); Se₈₀Te_20-xCd_x (x= 2, 4, and 10); and Se₈₀Te_20-xSn_x (x= 2, 4, and 10). The starting materials of (99.999%) purity were weighted according to their atomic percentages and sealed in evacuated silica tubes, under a pressure of about 10 …

Rehabilitation Of Concrete Structure Using Composite Materials, Ibtesam J.Saeed Al-Saifi

Theses

In the United Arab Emirates, most of the concrete structures including road, infrastructure and different types of buildings have been reported to be in need of rehabilitation. It is universally acknowledged that the environment of the countries in the Arabian Gulf is extremely severe and very aggressive to construction materials and operations. It is anticipated that the cost of rehabilitation of civil infrastructure will gradually increase over the next decade as a direct consequence of the increase in the number of structures reaching their expected service life.

Accordingly demand on rehabilitation methods will increase. In addition the severe climatic conditions …

Processing And Optimization Of Natural Fiber Reinforced Composites Using Date Palm Fibers, Khalifa Musabbeh Suwaidan Hamad Al-Kaabi

Theses

During the last twenty years, ecological concerns have resulted in a renewed interest in natural materials. Composite materials usually depend on using man-made fibers as the reinforcing element. The possibility of using natural fibers instead of synthetic fibers is gaining acceptance among users. This work aims to investigate the possibility of extracting natural fibers from date palm trees to be used as reinforcement with polymeric materials. The objective was achieved by characterizing fibers through different chemical, physical and mechanical tests and using different treatment methods in order to modify the fiber properties. Date Palm Fibers (DPF) exhibit a cylindrical shape …

Synthesis And Characterization Of Polyaniline And Poly (3-Methylthiophene) As Conducting Polymers, Fatma Khalifa Obaid Dalmouk

Theses

The performance of materials in general depends on their properties. There is a continuous need of new materials to meet the technological revolution that was witnessed by the end of last century. In this work, a new class of materials was synthesized. The host matrix is an Organic Conducting Polymer (OCP) of either poly(3-methylthiophene) (PMT) or poly(aniline) (PAN). The synthesis of OCP is achieved using electrochemical methods of applying constant potential or cyclic voltammetry at a platinum or graphite substrate in an acetonitrile containing tetra-alkyl-ammonium salt. The set up is three-electrode system of a platinum counter electrode and a silver/silver …

Bulk Polymerization And Structure-Property Relationship Of Medical Grade Polyurethane, Mariam Nasser Al-Saedi

Theses

Polyurethanes as biomaterials have been used in the augmentation and repair of the human body with great success. The choice of material for a particular application often hinges on the body's response to the polymer, the mechanical and thermal properties of the polymer and the stoichiometric ratio of active ingredients used in the synthesis.

A large number of polyurethanes used in medical applications are polyester-based and cannot be used in long-term implant applications because they are very susceptible to hydrolysis. Other medical-grade polyurethanes, which are suitable for implants are polyether-based which might to some extent, suffer from environmental stress cracking …

Chemical Vapor Deposition Of Polymeric Films, Chi Yu

Theses

Poly-peri-naphthalene (PPN) is a one-dimensional (1 -D) graphite polymer with unique planar ladder-like conjugated molecular structure. PPN was predicted to be a good intrinsic conductor and have high thermal stability and high environmental stability.

In this project, chemical vapor deposition (CVD) and plasma enhanced chemical vapor deposition (PECVD) of carbon films with PPN structure using PTCDA as precursor were carried out under different conditions. There is only limited information in literature on the synthesis of PPN films by PECVD process, which may allow deposition at a higher rate with lower substrate temperature. In this work the influence of deposition parameters, …