Materials Science and Engineering Commons^™

Clinical And Mechanical Evaluation Of A New All-Ceramic Restorative Material Turkom-Cera., Bandar Mohammed Abdullah Al-Makramani

Student Works (2010-2019)

The mechanical properties and clinical performance of Turkom-Cera system were evaluated in this study. The mechanical properties evaluated were; flexural strength, microhardness, shear bond strength, fracture resistance and marginal integrity. The biaxial flexural strength and hardness of Turkom-Cera compared to two other allceramic systems (In-Ceram and Vitadur-N) were investigated. The Turkom-Cera exhibited significantly higher flexural strength (506.8 MPa) than In-Ceram (347.4 MPa) and Vitadur-N (128.7 MPa) ceramic materials. However, In-Ceram core has significantly higher hardness (1116.2 VHN) than Turkom-Cera (1002.1 VHN) and Vitadur-N (812.8 VHN) all-ceramic materials. In order to find the optimal choice of luting cement and surface treatment …

Structural And Magnetic Properties Of Neodymium–Iron–Boron Clusters, Jeremy J. Anderson

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Using inert gas condensation techniques the properties of sputtered neodymium-iron-born clusters were investigated. A D.C. magnetron sputtering source created vaporous Nd-Fe-B which was then condensed into clusters and deposited onto silicon substrates. A composite target of Nd-Fe-B discs on an iron plate and a composite target of Nd-(Fe-Co)-B were utilized to create clusters. The clusters were coated with a carbon layer through R.F. sputtering to prevent oxidation.

Samples were investigated in the TEM and showed a size distribution with an average particle diameter of 8.11 nm. The clusters, upon deposition, were amorphous as indicated by diffuse diffraction patterns obtained through …

Room-Temperature Protonic Conduction In Nanocrystalline Films Of Yttria-Stabilized Zirconia, Hugo J. Avila-Paredes, Enrique Barrera-Calva, Harlan U. Anderson, Roger A. De Souza, Manfred Martin, Zuhair A. Munir, Sangtae Kim

Materials Science and Engineering Faculty Research & Creative Works

We report the results of our investigation on protonic conduction in 1 µm-thick polycrystalline films of 8 mol% yttria-stabilized zirconia (YSZ) with an average grain size of 17 nm prepared on sapphire substrate using a spin-coating process. Protonic conductivity of the films is found to be higher by over an order of magnitude (at 30 °C) than earlier reported values for nanocrystalline YSZ bulk ceramics with a similar grain size. This value is comparable to the oxygen-ionic conductivity of this material presented at about 400 °C. These results suggest that, besides grain size, the structural characteristics of the grain boundaries …

Tribological Comparison Of Traditional And Advanced Firearm Coatings, Greg Boban

Master's Theses

The objective of this project is to find which type of coating has the best performance characteristics for finishing firearms. This is accomplished by measuring and comparing several performance characteristics, such as: adhesion, hardness, wear resistance, friction control, and corrosion resistance. Appearance is not a factor since any exterior coating that is flashy can be subdued or camouflaged with special purpose paints, which have proven durable enough for such purposes. Cost will not be a limiting factor for this experiment, but will be discussed in the conclusion as a secondary concern. This data will be used to identify the best …

Effect Of K2o/Sio2 Ratio On The Crystallization Of Leucite In Silicate-Based Glasses, P Sooksaen, J Boonmee, C Witpathomwong, S Likhitlert

Journal of Metals, Materials and Minerals

Leucite-based glass-ceramics were prepared by controlled crystallization of suitable glass compositions to give required crystalline phase/s. Three glass batches in the system SiO2 - K2O - NaO2 - Al2O3 - TiO2 - CaO were prepared by varying K2O/SiO2 ratio, then melted and quenched. Glasses were characterized for onset of crystallization temperatures by differential thermal analysis (DTA), and heat treatments were carried out from 850 - 1000°C for 4 hours for controlled crystallization of leucite phase. Physical, chemical and crystal structure characterizations were carried out using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). XRD found …

Effect Of Chitosan's Molecular Weights On Mangosteen Dye Fixation On Cotton Fabric, C Suitcharit, F Awae, W Sengmama, K Srikulkit

Journal of Metals, Materials and Minerals

The effect of chitosan's molecular weights (Mw) on mangosteen dye fixation on cotton was studied using chitosans with Mw of 226 kDa (CTS-Mw I; native chitosan), 10.8 kDa (CTS-Mw II), and 7.2 kDa (CTS-Mw III). The preparation of chitosan with different Mws was carried out using sodium nitrite in acid media (depolymerization process). The obtained chitosans were applied onto cotton fabric. The effect of chitosan concentrations on fixation and fastness properties of mangosteen dye extract was studied. The results showed that an increase in concentrations of depolymerized chitosans (CTS-Mw II and III) yielded an increase in N% contents. Nonetheless, the …

Utilization Of Fly Ash From Power Plant For Adsorption Of Hydrocarbon Contamination In Water, J Sasithorn, D Wiwattanadate, S Sangsuk

Journal of Metals, Materials and Minerals

Adsorption efficiency of polycyclic aromatic hydrocarbons (PAHs) contamination in water with rice husk fly ash from a power plant was investigated in comparison with coal fly ash and silica from rice husk fly ash, with and without surface treatment. Naphthalene was used as a representative for PAHs, and Cethyltrimethylammoniumbromide (CTAB) was used as surface treating agent for the present study. Various factors, such as shaking rate, shaking time, pH of naphthalene aqueous solution, and adsorbentnaphthalene weight ratio, were investigated to identify the optimum condition for each adsorbent. Upon using 0.3 g adsorbent in 100 ml of 10 mg/l naphthalene solution, …

An Investigation Of Microstructural Change Of Low Alloy Steel Aisi 4150 By Seebeck Coefficient, T Samran, P Termsuksawad

Journal of Metals, Materials and Minerals

Low alloyed steels, whose hardness can be modified by heat treatment, have been widely used in various applications. After heat treatment, they are normally destructively characterized and tested by many approaches via optical microscope and hardness testing. It is useful to develop a non-destructive method relating to its properties and microstructures. The proposed non-destructive approach in this study is the Seebeck coefficient measurement. The materials in this study were carbon steels AISI 4150 rod with a diameter of 1.3 cm and length of 3 cm. The specimens were heat-treated at 900ºC for 1 hour and were then cooled to room …

Adhesion Behavior In Sliding Test Of Austenitic Stainless Steel On Vc Coated By Trd Process, R Piewnim, P Sricharoenchai

Journal of Metals, Materials and Minerals

Austenitic stainless steel is prone to adhere to tool steels which are used as forming tools. This causes difficulties in the formation of stainless steels.(1) Hard coating on forming tools is a method to diminish adhesion problems. In this work, adhesive behavior of stainless steel was tested against VC coated by thermo-reactive deposition and diffusion (TRD) process. Sliding wear test was conducted under unlubricated condition at room temperature by a ring-on-disc tester. AISI 304 was used as a ring for sliding couple with VC coating layer. DC 53 steel was used as a disc on which VC with a thickness …

Pickling Kinetics Of Tertiary Oxide Scale Formed On Hot-Rolled Steel Strip, Y Jatuphaksamphan, N Phinichka, K Prapakorn, M Supradist

Journal of Metals, Materials and Minerals

During hot rolling process a steel strip covers with oxide scales. These scales have to be removed by acid pickling process. This work focuses on the study of the scale removing rate of a hot-rolled steel strip in order to find an expression explaining the rate of reaction in hydrochloric acid. The study of scale removal is accomplished by utilizing the pickling simulator with different acid concentrations and pickling temperatures. There are two approaches that can be used to find a scale removing rate; the measurement of weight change and the iron concentration change after the pickling process. In this …

Preparation Of Hydrophobic Chitosan Using Complexation Method For Pla/Chitosan Blend, P Chouwatat, P Polsana, P Noknoi, K Siralertmukul, K Srikulkit

Journal of Metals, Materials and Minerals

In this study, dioctyl sulfosuccinate-chitosan complex was prepared by a mechanical mixing of aqueous chitosan with sodium dioctyl sulfosuccinate. As a result, hydrophobic chitosan was achieved. Characterizations of the complex were carried out including XRD, TGA, and FT-IR in order to follow changes in the chitosan structure. Thus produced chitosan complex was hydrophobic and anticipated to be compatible with PLA. Solution blending of PLA and hydrophobic chitosan was then conducted. Characterization techniques including XRD and FT-IR were employed to investigate the structure of the polymer blend. FTIR spectra showed that changes in the fingerprint of the chitosan amide band in …

Thermal Analysis Of Fe-Carbide And Fe-C Mixtures, R Tongsri, B Vetayanugul

Journal of Metals, Materials and Minerals

Differential thermal analysis (DTA) was employed to monitor changes which occurred during heating of Fe-carbide and Fe-C mixtures. The DTA curves showed a relationship between endothermic peaks and phase transformations given in the Fe-C phase diagram. The transformations included (i) magnetic Fe to non-magnetic Fe, (ii) pure α-Fe to pure γ-Fe, (iii) γ + Fe3C → Liquid and (iv) pure γ-Fe to pure δ-Fe. Melting of the Fe-SiC powder compacts when sintered at temperatures higher than 1200°C was revealed and indicated by the endothermic peak of 1230°C. This peak corresponded to the transformation of γ + Fe3C → Liquid. That …

Study Of Process Parameters In Conventional Powder Metallurgy Of Silver, S Amaranan, A Manonukul

Journal of Metals, Materials and Minerals

Compaction, sintering and physical properties of silver powder were investigated. The silver powder was uniaxially compacted into a cylindrical specimen using compaction pressures of 13.79, 27.58, 41.37 and 55.16 MPa. Compacted parts were sintered at 700, 800 and 900°C in argon atmospheres. In addition, compacted parts were also sintered in vacuum at 900°C. For the sintering temperatures of 700 and 800°C, it was found that the sintered density increased as the compaction pressure increased below 40 MPa, while the sintered density decreased at a compaction pressure above 40 MPa. At the sintering temperature of 900°C, the sintered density decreased with …

Effects Of Replacing Binder With Powder Space Holder On Properties Of Metal Injection Moulded Foam, U Koikul, A Manonukul, S Suranuntchai

Journal of Metals, Materials and Minerals

Metal foam can be produced using metal injection moulding with powder space holder. In this study, the effects of volume fraction of spacer holder on the foam properties were studied. Spherical poly (methyl methacrylate) (PMMA) particles were used as a space holder material. The 30% volume fraction of stainless steel 316L powder was mixed with varied volume fractions of binder and PMMA. There were five volume fractions of PMMA, namely 30% to 50%, with an increment of 5%. The results showed that the volume fraction of PMMA affected the properties. As the volume fraction of PMMA increased, the number of …

Study Of Covering Conditions For Sintering Of Metal Injection Moulded Commercially Pure Titanium, N Muenya, A Manonukul

Journal of Metals, Materials and Minerals

In metal injection moulding process, sintering for some specific materials is different from general materials. Titanium is a material that is not easy to sinter because it is a very reactive metal at high temperature. The high quality of the titanium component is difficult to control, especially so in point of the levels of carbon and oxygen, which have large effects on the mechanical properties. Commercially pure titanium was injected, debinded and sintered at 1150°C and 1250°C in high vacuum without a cover, and with a quartz cover, a mullite cover and an alumina cover, respectively. From the physical and …

Boron Carbide Based Solid State Neutron Detectors: The Effects Of Bias And Time Constant On Detection Efficiency, Nina Hong, John Mullins, Keith Foreman, Shireen Adenwalla

Shireen Adenwalla Papers

Neutron detection in thick boron carbide(BC)/n-type Si heterojunction diodes shows a threefold increase in efficiency with applied bias and longer time constants. The improved efficiencies resulting from long time constants have been conclusively linked to the much longer charge collection times in the BC layer. Neutron detection signals from both the p-type BC layer and the n-type Si side of the heterojunction diode are observed, with comparable efficiencies. Collectively, these provide strong evidence that the semiconducting BC layer plays an active role in neutron detection, both in neutron capture and in charge generation and collection.

Feasibility Of Manipulating Correlated Color Temperatures With A Phosphor Converted High-Powered Light Emitting Diode White Light Source, Matthew Michael Little

Master's Theses

In this thesis we examine the feasibility of developing a white light source capable of producing colors between 2500 and 7500 Kelvin on the black-body radiator spectrum by simply adjusting amperage to a blue and ultraviolet (UV) light emitting diode (LED). The purpose of a lighting source of this nature is to better replicate daylight inside a building at a given time of day. This study analyzes the proposed light source using a 385 nm UV LED, a 457 nm blue LED, a 479 nm blue LED, a 562 nm peak cerium doped yttrium aluminum garnet (YAG:Ce) phosphor, and a …

The Effects Of Carbon, Boron And Vanadium On The Microstructural Evolution And Hardness Of Steel-Based Hardfacing Alloys, Kyle Rafa

Materials Engineering

Current hardfacing alloys provide insufficient wear resistance due to either cracking or significant material wear. To increase wear resistance of steel-based hardfacing alloys, the effects of composition on microstructure and hardness were investigated in a progression of alloys. Initially, seven new alloys were prepared varying the carbon-boron ratio with the total constant at 3 wt%. Small arc-melt cast circular ingots were produced roughly 1 x 0.5 inches. Metallography provided insufficient phase magnification, thus a SEM equipped with EDS was used, allowing for microstructure and phase composition analysis. Four distinct carbide phases were found and image analysis software allowed for carbide …

The Characterization And Analysis Of In-Vitro And Elevated Temperature Repassivation Of Ti-6al-4v Via Afm Techniques, Aaron J. Guerrero

Master's Theses

ABSTRACT

The Characterization and Analysis of In-vitro and Elevated Temperature Repassivation of

Ti-6Al-4V via AFM Techniques

Aaron J Guerrero

Research in the corrosion of orthopaedic implants is a growing research field where implants have been known to show adverse effects in patients who have encountered the unfortunate dissolution of their implants due to corrosion. Once corrosion begins within the body, many adverse biological reactions can occur such as late on-set infections resulting in severe health complications. The focus of this research is specifically related to the problem of late on-set infections caused by localized corrosion of orthopaedic implants. In medical …

Design, Fabrication, Structural Testing, And Numerical Analysis Of A Small Scale Composite Wing, Jacob David Gaunt, Juan Carlos Flores, Vincent Andrew Perry

Aerospace Engineering

A small scale composite wing based on a design found on an experimental aircraft was designed, constructed, and tested dynamically and statically. The wing was constructed similarly to an experimental aircraft wing. The performed static test was intended to produce pure bending. Strain gages were used to measure strains on the wing structure. The strains were converted to stresses to aid in analysis. The static test results suggested that the wing was actually under torsion. Four structural modes were found from the static test. A finite element analysis model was made to compare experimental results to numerical analytical results. The …