Mariyam Jameelah Ghazali

Surface Modifications and Their Effects on Titanium Dental Implants

This review covers several basic methodologies of surface treatment and their effects on titanium (Ti) implants. The importance of each treatment and its effects will be discussed in detail in order to compare their effectiveness in promoting osseointegration. Published literature for the last 18 years was selected with the use of keywords like titanium dental implant, surface roughness, coating, and osseointegration. Significant surface roughness played an important role in providing effective surface for bone implant contact, cell proliferation, and removal torque, despite having good mechanical properties. Overall, published studies indicated that an acid etched surface-modified and a coating application on commercial pure titanium implant was most preferable in producing the good surface roughness. Thus, a combination of a good surface roughness and mechanical properties of titanium could lead to successful dental implants.

Physicochemical and thermal properties of lignocellulosic fiber from sugar palm fibers: effect of treatment

Sugar palm fiber (SPF) is one of the prospective fibers used to reinforce polymer composites. The aim of this study is to evaluate the physicochemical, thermal, and morphological properties of SPF after alkali and sea water treatments. The chemical constituents group and thermal stability of the SPF were determined using scanning electronic microscopy (SEM) along with energy dispersive X-ray spectroscopy and thermogravimetric analysis (TGA). Fourier transform infrared spectroscopy was carried out to detect the presence of functional groups in untreated and treated SPF. The SEM images after both treatments showed that the external surface of the fiber became clean as a result. However, the sea water treatment affected the fiber properties physically, while the alkali treatment affected it both physically and chemically by dissolving the hemicellulose in the fiber. The TGA results showed that untreated fiber is significantly more stable than treated fiber. In conclusion, the results show that the fiber surface treatment significantly affected the characterization of the fiber.

Laser surface texturing and its contribution to friction and wear reduction: a brief review

Purpose – The purpose of this paper is to make people aware of the increase usage of laser system in surface texturing process. Design/methodology/approach – As it is a brief review paper, no particular method was used. Findings – It has been found that most of the surface texturing methods used mas laser beam machining using Nd:YAG laser. It shows that the realization of the textured surface helps to reduce friction and wear which can increase the life span of a material. Research limitations/implications – Most of the texturing is done on the substrates directly, and few research were conducted on coated surface of the material, which coating is also known as an excellent method to improve tribological properties. Originality/value – The paper shows details on the recent development of surface texturing and its contribution to friction and wear reduction.

Correlation of filler loading and silane coupling agent on the physical characteristics of epoxidized natural rubber-alumina nanoparticles composites

Studies were conducted on the effects of filler loading and 3-aminopropyltriethoxysilane (SCA) on the physical characteristics of epoxidized natural rubber (ENR)-alumina nanoparticles composites (ENRAN). The filler loading varied from 10, 20, 30, 40, 50, and 60 phr in the absence and presence of 2 phr SCA in every formulation. The alumina nanoparticles have a positive interaction with the ENR matrix since they increase the glass transition temperature of the composites [Mohamad, N., Muchtar, A., Ghazali, M.J., Dahlan, H.M. and Azhari, C.H. (2008). The Effect of Filler on Epoxidized Natural Rubber-Alumina Nanoparticles Composites, Eur. J. Sci. Res., 24: 538—547]. The addition of SCA decreased the maximum torque (MH) and the torque difference (MH-ML) of ENRANs compound as well as causing the curing process to occur at a very fast rate. The spherical alumina particles were dispersed in ENR matrix and a uniform particle distribution was observed under scanning electron microscope enabling the increase of the torque values in the composites.

Online Cutting Tool Wear Monitoring Using I-Kaz Method and New Regression Model

This study presents a new method for detecting the cutting tool wear based on the measured cutting force signals using the regression model and I-kaz method. The detection of tool wear was done automatically using the in-house developed regression model and 3D graphic presentation of I-kaz 3D coefficient during machining process. The machining tests were carried out on a CNC turning machine Colchester Master Tornado T4 in dry cutting condition, and Kistler 9255B dynamometer was used to measure the cutting force signals, which then stored and displayed in the DasyLab software. The progression of the cutting tool flank wear land (VB) was indicated by the amount of the cutting force generated. Later, the I-kaz was used to analyze all the cutting force signals from beginning of the cut until the rejection stage of the cutting tool. Results of the I-Kaz analysis were represented by various characteristic of I-kaz 3D coefficient and 3D graphic presentation. The I-kaz 3D coefficient number decreases as the tool wear increases. This method can be used for real time tool wear monitoring.

Perspectives for Titanium-Derived Fillers Usage on Denture Base Composite Construction: A Review Article

Poly(methyl methacrylate) (PMMA) is an extensively used material in dentistry because of its aesthetics, processability, and reparability. However, PMMA is still far from being ideal in fulfilling the mechanical requirements of prosthesis. PMMA-based denture base polymers exhibit low fracture resistance and radiopacity behavior. Efforts to improve the mechanical and radiopacity properties of denture base materials through inclusion of silica-based fillers are ongoing. Although silane-treated siliceous fillers are commonly used, they are not sufficiently strong. They also exhibit cracks, which either cut through the glass fillers or propagate around the filler particles. This defect occurs when the dental composites are placed in aqueous oral environment because of the hydrolytic degradation of silica-based fillers and silane-coupling agents. The clinical problem of using silanes in adhesion promotion is bond degradation over time in oral environment. In addition, silanes do not bond effectively to nonsilica-based dental restorative materials. This review presents titanium-derived fillers as alternatives to siliceous fillers. Titanate-coupling agents are found to be effective couplers in treating Ti-based fillers because of their chemical compatibility and relatively high stability in aqueous environment.

Enhancing material performance through laser surface texturing: a review

Materials with well-defined surface structures are prepared using protective coatings through surface texturing, which is a novel method for modifying surface characteristics, particularly tribological and wettability, to improve the properties of material parts. The formation of a specific patterned surface can be achieved through abrasive blasting, reactive-ion etching, lithography and mechanical machining. This review focuses on laser technology because it generates the most controllable and precise geometries. This technique is environmentally friendly because it does not utilise any chemical reagent, nor does it produce significant waste.

Mode III Stress Intensity Factors of Surface Crack in Round Bars

This study presents a numerical investigation on the stress intensity factors (SIF), K of surface cracks in round bars that were obtained under pure torsion loadings or mode III. ANSYS finite element analysis (FEA) was used to determine the SIFs along the crack front of surface cracks embedded in the solid circular bars. 20-node isoparametric singular elements were used around the crack tip by shifting the mid-side node ¼-position close to a crack tip. Different crack aspect ratio, a/b were used ranging between 0.0 to 1.2 and relative crack depth, a/D were ranged between 0.1 to 0.6. Mode I SIF, KI obtained under bending moment was used to validate the proposed model and it was assumed this proposed model validated for analyzing mode III problems. It was found that, the mode II SIF, FII and mode III SIF, FIII were dependent on the crack geometries and the sites of crack growth were also dependent on a/b and a/D.

Wear behaviour of eutectic and hypoeutectic Al‐Si‐Mg‐Ce alloys

Purpose – The purpose of this paper is to study the wear behaviour of eutectic and hypoeutectic Al‐Si‐Mg‐Ce alloys.Design/methodology/approach – The eutectic and hypoeutectic alloys were prepared using permanent mould casting process by varied cerium (Ce) addition in the alloy from 1 to 3 wt%. Dry sliding wear tests were performed against a hardened carbon steel (Fe‐2.3%Cr‐0.9%C) using a pin‐on‐disc configuration with fixed sliding speed of 1 m/s and load 50 N at room temperature of ∼25 degree. Morphologies of both worn surfaces and collected debris were characterised by a scanning electron microscope (SEM) equipped with an energy dispersive X‐ray spectrometer (EDS).Findings – It was revealed that following the addition of cerium, intermetallic Al4Ce needle‐like structure was present in eutectic alloys whereas CeMg2Si2 blocky phase was present in the hypoeutectic alloys. The increasing of Ce addition up to 3.0 wt% in hypoeutectic alloy led to formation of AlCe3 intermetallic phase. The increase in cerium ...

Effects of Al2O3-13% TiO2 Coating Particle Size on Commercial Mild Steel via Plasma Spray Method

This paper discusses the effect of Al2O3-13% TiO2 agglomerated nanoparticle powders ranging from 20 to 60 m and microparticle powders ranging from 10 to 25 m on commercial marine grade mild steels using a plasma spray technique. Prior to coating, the nanoparticle powders were subjected to a 2 level factorial design of experiment to give a careful control and optimise the operational spray parameters as well as process by using the statistical methods. The method was focused on the primary gas pressure, carrier gas pressure and powder feed rate of the spray parameters. The optimum properties of wear rate, surface roughness and microhardness were identified by using the lowest primary and carrier gas pressure together with the highest powder feed rate. As for the microparticle powders, they were subjected to an optimum properties by using 35 kW plasma spray power. In this study, the plasma spray power for microparticle varied from 20 kW to 40 kW, while the other parameters such as primary gas pressure, carrier gas pressure, powder feed rate and spray distance were held constant. It was found that microparticle powders exhibited denser coating microstructure s and improved both surface roughness and microhardness. On the other hand, the nanoparticle powder coating gave a greater wear resistance than those of micro particle powders, which may likely due to the strengthening effect of both fully and partially melted region.