Fiber reinforced polymer (FRP) composites have been steadily replacing metals as choice engineering materials for various applications. Although FRPs can be manufactured to near-net shape, post processing operations such as machining are required to create some features (such as holes). As FRPs are multiphase materials with complex load-response behavior, there is a need to analytical and numerical approaches to fully understand the machining process. This paper objective focuses on the development of the optimum cutting conditions leading to damage free drilling of GFRP using response surface methodology (RSM)[1]. For this purpose, a number of machining experiments based on statistical four-level full factorial design of experiments method are carried out in order to collect comprehensive data and analyzed using commercial statistical software MINITAB14. Finally, optimum cutting condition produced from RSM is verified with the experimental measurement for observing accuracy of the developed response surface model.

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Polymer layered silicate nanocomposites can improve the flexural and compressive strength of continuous fibre reinforced composites by means of increasing the matrix modulus. The nanocomposite matrix has a modulus that is much higher than the neat matrix, even above T_g and after moisture conditioning. The results showed that the fibre composites with a nanocomposite matrix have a more than 40% increased flexural and compressive strength at elevated temperatures. Therefore, by using a nanocomposite matrix the high temperature performance of fibre composites can be improved without any change in processing conditions.

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Composite laminates of low density polyethylene (LDPE) and polypropylene (PP) with pineapple leaf fiber (PALF) were made by sandwiching one layer of fiber between two layers of polymer films with different fiber orientations and lengths (uni-direction and non-woven mat, long and short fibers), fiber contents (0-30%) and composite thickness (0.5 and 1 mm). The results show that PALF utilization as high-strength reinforcing fiber for LDPE and PP matrix provided an increased tensile strength with PALF contents while the elongation was sharply decreased. The fiber orientation in the uni-direction could be attributed to the greater adhesion in the polymer matrix, which resulted in individual and separated dispersions in the matrix. However, the fiber orientation in the non-woven mat could be controlled easier in process, and homogeneous arrangement showed that the tensile strength results were not significantly different for both polymers and sheet thicknesses.

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In this study, In situ-reinforcing elastomer composites based on Santoprene thermoplastic elastomer (a polymerized polyolefin compound of ethylene-propylene-diene monomer (EPDM) and polypropylene (PP)) and a thermotropic liquid crystalline polymer (TLCP), Rodrun LC3000, were prepared using a single screw extruder. The effect of TLCP contents on rheological behavior, morphology, mechanical and thermal properties of the blends were investigated. All neat sample and their blends exhibited shear thinning behavior. TLCP acted as a processing aid during processing; the viscosity of the blends gradually decreased with increasing TLCP contents. The thermal stability and mechanical properties of Santoprene were significantly improved by addition of TLCP.

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High strength/high modulus fibers were prepared from polyethylene (PE) by melt spinning/hot drawing process. The fibers displayed an improved mechanical properties with increasing draw ratio. Modulus and tensile strength up to 35.6 GPa and 1.13 GPa, respectively, were obtained. All fibers displayed very similar work of rupture although their % elongation at break decreased with increasing draw ratio. These PE fibers were pressed into cross-ply composite by film stacking process. The composite displayed much higher puncture impact strength than isotropic PE.

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High strength polypropylene (PP) fiber was prepared from PP/clay composite by melt spinning process. Mechanical properties and morphology of as-spun and drawn fibers from PP/Clay composite were compared with that of neat PP. The results showed that PP/Clay composite had a better drawability, and provided fibers with improved mechanical properties at a clay content of 10%.

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A thin-core flexible substrate made of a multi-layered composite of metal and polymer components was subjected to different temperature conditions and analyzed for its warpage behavior. The warpage behavior was carefully measured at different intervals up to the peak temperature. Two warpage mechanisms were observed and the mechanical properties of the individual layers of the substrate were found to contribute to these varying behaviors.

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Oxidation activity of titanium dioxide on alumina can be improved by incoproration of vanadium and silver. TiO_2 nanoparticle catalyst was prepared by sol-gel technique on alumina beads. Vanadium and silver were loaded into the catalyst by coprecipitation and impregnation, respectively. The prepared TiO_2 catalysts were tested for methanol oxidation. The reactions were carried in a fixed bed reactor at 350℃ with W/F of 24.5 g_<cat>.g_<MeOH>^<-1>.hr^<-1>. Liquid products were periodically collected and analyzed by FID-GC while gas products were detected by online-TCD-GC. Incorporation of silver showed a significant improvement for oxidation activity, as compared to vanadium. For Ag-TiO_2 catalyst, impregnation technique provided a better activity than the coprecipitation. It was found that, 3% TiO_2 catalyst incorporated with 0.6%Ag is the most effective catalyst in this study.

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A comparative study of titanium oxide powders prepared by precipitation and sol-gel methods was conducted. Titanium tetrachloride and ammonium hydroxide were used in the hydrolysis of Ti in the precipitation process. For the sol-gel method, titanium tetra-isopropoxide was used as the starting material. Hydrolysis followed by peptization were performed in an acidic alcohol solution. Powders obtained from the two preparation methods were calcined at 400℃ to obtain TiO_2 powders. XRD, TEM, SEM and BET results indicated differences in crystal structure, morphology and surface areas of the powder prepared by different techniques. This, hence, resulted in different photocatalytic activities of the powders tested using methylene blue excited with UV light at the wavelength of 661 nm.

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The present study shows that the aging time of sol-gel process used to prepare the TiO_2 powder had pronounced effect on anatase-rutile phase transformation and the crystalline size. The complete rutile phase transformation was observed within 40 days of aging. The results of XRD and TEM were presented to explain this phenomenon.

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TiO_2 nanoparticles have been synthesized using titanium (IV) isopropoxide. SEM imaging revealed that TiO_2 nanoparticles with an average diameter of 15 nm. The physicochemical properties of TiO_2 film papered by a spin coating on a glass slide were determined. A thickness of film was estimated by SEM. The reflective index of TiO_2 coating was determined by simulation method. The TiO_2 was applied to modify electrode and exhibited catalytic activity for chlorophenol, 2-chlorophenol, and 4-nitrophenol, as three test models.The detection limits was 1μM with linearity up to 10μM.

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In this work, nanocrystalline Pd/CeO_2 catalyst had been synthesized under room temperature using microemulsion method. Cerium nitrate and palladium chloride were used as starting materials. In this procedure, two microemulsion solutions containing surfactant, co-surfactant, oil phase and aqueous solution of different reactant were prepared. One of microemulsion systems contained the mixture of Pd^<2+>and Ce^<3+> solutions that were mixed at an appropriate ratio. Another system contained sodium hydroxide solution. Both solutions were then mixed at room temperature producing the Pd/CeO_2 nanoparticles. Structure and properties of the synthesized particles were investigated using XRD, TEM, and gas adsorption-desorption analysis. It was found that the crystal structure of synthesized particles was FCC with an average crystallite size of about 4 nm. The average size of particles investigated using TEM was found to be around 4.1 nm.

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The purpose of present research is to estimate the degradation mechanism of solid oxide fuel cell (SOFC) by using combining non-destructive test and electrochemical measurement during loading test Mechanical degradation and chemically degradation were investigated by acoustic emission (AE) measurement system and electrochemical measurement,respectively. In the investigation of fracture process with AE amplitude distributions, high amplitude signal, middle amplitude signal and low amplitude signal correspond to vertical craking, delamination in the cathode, and vertical cracking in the elctrolyte respectively. It was demonstrated that the AE method enabled us to detect the above-mentioned mechanical damage and to determine the condition for the onset of the damage in the single cell.

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Recent developments on intermediate temperature (550 to 750℃) ITSOFCs have been carried out using functional ceria-composite materials, which have demonstrated its potential for commercialisation. The work reported here involved a compressed cell fabrication technique to fabricate the cells and to developa technology in scaling-up of the ITSOFCs for practical applications. The single cells fabricated have reached hundreds of mAcm^<-2> with a maximum power density of >100 mW cm^<-2> at a temperature of 550-750℃. The active area of the tested cell was 0.785 cm^2. Initial results are promising.

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We developed a low cobalt composition Alnico-type magnet having the magnetic properties equivalent to Alnico-5 (MK-5) magnet. An energy product of (BH)_<max>=4.94 MGOe, coercive force of H_c=647 Oe, and remanence of B_r=12.45 kG were achieved in a 20%Co alloy adding 0.8% of Nb.

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The effect of different thickness of NiFe films on magnetic their properties have been investigated. NiFe films were electroplated on a copper substrate. The plating time was varied on a certain current density to achieve two different thicknesses i.e. 3 and 50 μm of the plated film. The NiFe films were characterized with X-ray diffraction, energy dispersive X-ray spectroscopy, and Alternating gradient magnetometer (AGM). The result indicates that magnetic properties were affected by thickness variation. Increase in thickness increased the saturation magnetization.

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In this study, TiO_2 nano-particles were synthesized using a sol route. Ag-doped TiO_2 particles were then prepared by impregnation by means of a dipping coating process. Strong porous α-alumina beads were prepared. SEM micro-structural investigations showed that the Ag-doped TiO_2 particles could attach onto the porous alumina beads. TEM observations also revealed that metallic Ag remained and had attached onto the TiO_2 grains after the synthesis process.

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In this work, an attempt was made to investigate influences from cross cutter of spherical cutter on boundary layer of finished surface in high-speed milling process. Experiments such as analysing of residual stress, characteristics of micro-hardness and microstructure have been conducted to analyse features of workpiece surface, which is created under condition of high-speed milling and different technology conditions. In addition, the experiment results have proved unexistence of new hard-zone at boundary layer of finished surface when cross cutter takes part into cutting process.

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The overall goal for this work is to develop a mechanics of cutting based procedure for selecting the appropriate cutting condition, specifically, the optimal feed value selection under the assumption that optimal values of cutting speed and depth of cut are known for multi-axis milling. With the availability of today's high speed machining technology and the need for reducing machining time and cost, there is potential for improvement in the current milling process which will be described and shown.

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In this work, an attempt was made to compare the performance of steel and rubber lined mill by vibration signature technique. Grinding emits strong vibration signals due to the collision between grinding media, ore particles and the mill body. Variations of the vibration signals reflect the changes of the grinding state. Steel lined mill shows always high amplitude of vibration as compared to rubber lined mill and gives fine grinding.

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GTAW process is used for welding of pressure vessels made of hypo-eutectic Al-Cu alloy AA2219 containing 6.3% Cu. As welded Yield strength of the alloy was found to be in the range of 140-150 MPa, using conventional single pass GTAW technique on both AC and DCSP modes. Multipass GTAW on DCSP mode was postulated to improve the weld strength of this alloy. YS of 200 MPa has been achieved in the as welded condition. This paper presents the conceptual understanding of welding metallurgy of AA2219 alloy and validation by experiments, which could lead to better weld properties using multipass GTAW on DCSP mode.

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The residual stresses, mechanical properties and microstructures of welded A516 GR 70 plate steels with shield metal arc welding processes were investigated for three welding techniques: 1) full bead, 2) full bead with post weld heat treatment and 3) half bead temper welding. From tensile tests, all specimens of the three welding techniques ruptured at base metal area. The tensile strength of full bead and half bead temper welded specimens are close and higher than that of the full bead with post weld heat treatment specimen. The impact property of Heat Affected Zone (HAZ) of half bead temper welding technique is much higher than those of the other two techniques. The half bead temper welding reduces the residual stress along the weld direction in the weld bead and in the base metal, while it does not reduce the residual stress in the HAZ. In the plane across of the weld, the half bead temper welding does not reduce the residual stress in any of the three areas.

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This research is to study and to analyze the effect of energy of laser beam to the characteristic of joint of laser welding. The investigation of this relation will be leaded to the optimum of laser welding condition. The characteristics of joint of laser welding are considered such as orderliness of bead profile and defect of welding (i.e., pin hole, incomplete, crack, and leak). The experimental results has been shown that the energy of laser beam lower than 4.8 joules/pulse gives the defect of joint of laser welding while the energy higher than 4.8 joules/pulse gives the good condition of joint of laser welding.

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The Metallurgical change of laser welding of high temperature Oxide Dispersion Strengthened (ODS) ferritic stainless steel has been studied. The PM2000 laser weld microstructure was examined using a combination of optical microscopy, scanning electron microscopy and energy dispersive X-ray analysis. The results indicated that the welds reveal an agglomeration of yttrium oxide particles which were founded at the top of the surface as well as inside the weld. Furthermore, laser welding also changed microstructure of the bulk to the form of dendrite structure.

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Joining of plastics finds applications in medical, aerospace, electronic and automotive areas. Present study emphasizes on joining of thermoplastics and thermoplastic composites by two recent techniques namely Friction Stir Welding (FSW) and resistant welding. The processed joints were analyzed by mechanically and metallurgically. This study also describes a new method of the selection of process parameters for obtaining optimal weld/joint strength by non conventional optimization techniques.

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The microstructure and growth of intermetallic compounds(IMCs) of Sn-3.0%Ag-0.5%Cu solder on substrate between Cu/NiAu and Cu were investigated after aging at 150 C for various times. In case Cu/NiAu substrate, the interface IMCs layer was (CuNi)_6Sn_5. For Cu substrate, the IMCs layer was Cu_6Sn_5. During aging at 150 C, the thickness of (CuNi)_6Sn_5 layer grew gradually but the thickness of Cu_6Sn_5 layer grew rapidly at beginning and both seem to reach a certain value. The mean thickness of IMCs at interface was quite lower for Cu/NiAu substrate.

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The microstructure and growth of intermetallic compounds (IMCs) at the interface between Sn-3.0 %Ag-0.5 % Cu, Sn 3.8 %Ag-1.0 %Cu solder and Cu substrate during aging were studied. The soldering were conducted at 250℃ by dipping method. Cu_6Sn_5 (IMC) phase was formed instantaneously at the interface of the liquid solder and Cu substrate. During aging at 150℃ , the thickness of Cu_6Sn_5 layer grew rapidly at the beginning. The mean thickness of the IMC layer at the interface was higher for Sn-3.0 %Ag-0.5 % Cu solder alloy. However, growth rate of IMC layer decreased sharply with prolong aging time.

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By processing triangle or square pyramid shaped indents on a flat sheet following regular plane tiling patterns, panels with periodical indents are manufactured. By setting this panel (as top panel) on reversed one (as bottom panel), and gluing them at the apexes of pyramids to nodal points of the tiling patterns of bottom panel, highly rigid core panels are newly developed. The basic model named "dia-core" corresponds to the space filling models by two tetrahedra and one octahedron. Besides, varying the geometric patterns which appear on their surfaces, various modified models are devised. This pattern variation is known as Archimedean plane tiling in geometry.

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This research was for compared studying of microstructure from as-cast receive and the condition after heat process by studied about the effect of Nb to γ-TiAl based which had the composition of Ti-46A1, Ti48Al, Ti-46Al-5Nb, Ti-48Al-5Nb, Ti-46Al-10Nb and Ti-48Al-10Nb. Six alloys were prepared by arc-melt under argon atmosphere. Then divided work level into 2 groups, the first group was as-cast receive and the second was brought to heat treatment at 1350℃ for 6 hours with was protected by argon atmosphere. After that brought both of work pieces to be analyzed with optical and scanning electron microscopy, X-ray Diffraction and mechanical properties test. The result of research found that when Nb increased more would make columnar dendrite structure as-cast receive was decreased and disintegrated to equiaxed dendrite, it also effected to the quantity of lamellar γ-TiAl single phase had be increased stable when passed heat treatment in alloys Ti-46Al+Nb and effected to be decreased of columnar dendrite size when the quantity of Nb was increased more and effected to the grain size with more exhaustive in case of Ti-48Al+Nb.

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Reduced pressure test has long been used widely as a hydrogen measurement technique in aluminum foundries. Result in terms of hydrogen content obtained from this technique is, however, neither conclusive nor reliable enough. There are implications underlying the measured hydrogen level. In this study, a series of the reduced pressure test was conducted and values of hydrogen level of AlSi7 samples were subsequently evaluated employing quantitative density analysis. It is shown that, without proper practices in terms of casting conditions during the test, there exist significant discrepancies in the hydrogen measurement.

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This work presents an effort regarding improvement of investment casting system. An alternative design of investment casting system, primarily aimed for jewelry casting, has been developed. Emphasis has been placed on reduction of porosity as well as filling-related defects inherent to typical investment casting practices. The effort is based on the fundamentals addressing science of melting, filling and solidification. Brass was used in this preliminary work to investigate effectiveness of the newly designed investment casting system.

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This research explores the possibility of using the Selective Laser Sintering (SLS) technique originally employed in the Rapid Prototype (RP) process to generate an insert mold, thus, covering an entire process of mold making. The results revealed that the insert mold created from this process can be assembled with a standard mold base and is compatible with an injection molding process without any further modifications required. Moreover, the operating test also showed no significant damage to the mold.

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This paper investigates the possibility of creating an insert mold using an epoxy resin composite (aluminum, resin and hardener). The properties of epoxy resin composite and rapid tooling techniques are studied and discussed. The results indicate that the insert mold made from this material can be assembled with a standard mold base and is compatible with an injection molding process without any further modifications required. The operating test also revealed no significant damage to the mold. One limitation of this composite, however, is its poor thermal conductivity.

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Wear is a cause of failure in many engineering components especially involving high speed movement. Wear normally related to the surface roughness of the material and it's rate is high when two rough surfaces are in relative motion. Surface roughness of the material is commonly be measured using stylus profilometer. However there is limitation using of this method due location of the surface is inside the machine. The experimental work done with 250 kHz as an input frequency propagates through various artificial surface roughnesses, and then all responses are recorded. Results show that frequency of 250 kHz give a high potential in surface roughness identification.

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Polystyrene microspheres were a selected material to examine for the two-dimensional (2D) aggregation. The 2D aggregated clusters were confined between the two fiber cantilevers which can slide and move the aggregates in the lateral direction. The compressive yield stress was directly measured during experiment by quantitative image analysis on the optical microscope. Particle positions of all particles were located by a Discrete Element Method (DEM). The 2D mechanical properties were examined for the particle size scaling behaviors as a function of particle area fraction and the average particle coordination number. These studies were conducted to apply the yield stress of 2D aggregates, and compared to the yield stress of concentrated flocculated suspensions of the three-dimensional (3D) mechanical network

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High-purity aluminum is soft and ductile and thus, it is unsuitable for most commercial and engineering applications which require greater strength and hardness. Alloying, modification, cooling rate as well as heat treatment can increase the strength and hardness of aluminium alloys. In this study, the effects of heat treatment and modification were investigated with eutectic base Al-Si alloy (also known as LM-6 alloy). Silicon is the main alloying element that imparts high fluidity and low shrinkage, which results in good castability and weldability. Silicon's low thermal expansion coefficient is exploited for pistons and the high hardness of the silicon particles improves its wear resistance property. Strontium has the effect of refining the microstructure in a similar manner as achieved by using sodium. The effects of full heat treatment of LM-6 type alloy produced in green sand mould were also evaluated. Mechanical properties of the alloy have improved with all these variables, have been elaborated in this paper.

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In this work, the result of calcination temperature on phase formation and microstructure of (Pb_<1-x>Ba_x)TiO_3 ; 0.025&le;x&le;0.010 (PBT) powders were investigated. The PBT powders were prepared via the mixed oxide method under various calcinations temperatures (400-900℃). The TGA-DTA and XRD were evaluated the optimum conditions for calcinations. The c/a ratio increased with increasing calcination temperature up to 800℃ and the high purity of perovskite powders were obtained with calcination temperature at 800℃. The SEM result indicated that the particle size of the powders increased with increasing calcinations temperature.

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Nanoindentation tests have been applied to quantitative characterization of interfaces of bonded materials. Distributions of indentation hardness and Young's modulus on the material surface are precisely determined. Two kinds of bonded materials, a diffusion bonding of aluminum alloy and stainless steel and a spot welding of carbon steels, are used for specimens. It has been found that the intermetallic compound layer of 4μm produced at the interface of the diffusion bonding has higher mechanical properties than those of the base materials. Two-dimensional mapping of mechanical properties on the cross section of the spot welding has also successfully been performed.

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In the present work temperature distributions and microstructure zones in single pass SMAW butt joints have been studied, using three-dimensional finite element analysis. Based on experiments on a semiautomatic machine, area of heat flux was calculated for moving heat source based modeling. Filler metal deposition was simulated using element birth and death method. The experimental results were compared with the modeled values. The model was further extended to pipe welded joints of 5 and 8 mm thicknesses for predicting the temperature distributions and microstructure zones.

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Rubber moulds used in the injection moulding process in Thai rubber product industry are usually manufactured by the mould makers who often use skilled and experienced workers with trial-and-error method including conventional tools/ machines in mould design and manufacturing processes. As a result, various defects of the rubber products such as excessive flash and air trap are occurred. This leads to several mould try-outs and loss of raw material used in the process. Therefore, this research aims to apply the Computer Aided Design/ Engineering (CAD/CAE) techniques for optimized injection conditions. The significant input variables include material properties of the natural rubber (NR40) like heat conductivity, viscosity and shear rate, curing time and operating conditions like mould temperature, injection pressure, injection time including the gating and runner positions. The numerical results are also correlated well with the empirical data using the rubber injection machine. This research provides rubber researchers the tools to seek the best operating conditions in rubber injection moulding.

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Development of Rubber Mould Inline and Offline Process Inspection reduce lead time and increase the quality of mould inspection in terms of accuracy. For this study with two available methods selected: CNC control (Touch probe on machining centers) and hand-control (Portable arm Coordinate measuring machine), these equipments are used along with specialized software which is capable of measuring the three-dimensional coordinate as well as analyzing the result. Online process inspection is done on the machine during production of which the adjustment is made. Offline process inspection is examined after production which involves rechecking the dimensions before sending to the customer. The experiment results show that there is no significant difference between the two measurement methods. Nevertheless from operation point of view, the Portable Arm Coordinate measuring machine has an advantage in its simplicity, and require less operation lead time.

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Finite element method is presented to predict temperature distribution in anterior chamber of the eye, in a certain conditions during performing phacoemulsification. In thermal analysis several phacoemulsification conditions are varied such as type of balanced salt solution, viscoelastic fluid, position of phaco needle, phaco power. Temperature distribution solutions of several phacoemulsification conditions are presented. These results are good information to set up an avoidance critical phacoemulsifying situations that may reduce several damages in anterior chamber during and after phacoemulsification. The finite element results demonstrate its capability to predict temperature distribution in anterior chamber of the eye during phacoemulsification.

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