Applied Mechanics and Materials Vol. 315

Abstract: Surface roughness is an important output in different manufacturing processes. Its characteristic affects directly the performance of mechanical components and the fabrication cost. In this current work, an experimental investigation was conducted to determine the effects of various cutting speeds and feed rates on surface roughness in turning the untreated and Sb-treated Al-11%Si alloys. Experimental trials carried out using PVD TIN coated inserts. Experiments accomplished under oblique dry cutting when three different cutting speeds have been used at 70, 130 and 250 m/min with feed rates of 0.05, 0.1 and 0.15 mm/rev, whereas depth of cut kept constant at 0.05 mm. The results showed that Sb-treated Al-11%Si alloys have poor surface roughness in comparison to untreated Al-11%Si alloy. The surface roughness values reduce with cutting speed increment from 70 m/min to 250 m/min. Also, the surface finish deteriorated with increase in feed rate from 0.5 mm/rev to 0.15 mm/rev.

Abstract: Rapid prototyping (RP) process offers a promising economical way as a sacrificial pattern in investment casting (IC) at high speed and low cost for low volume part manufacturing. However direct sacrificial RP pattern have encountered shell cracking during burnout process due to polymer based materials. Shell mould thickness was need to be concerned to have strong enough to withstand RP part expansion for employing direct method. The aim of present research was to compare the efficacy of different shell thickness for aluminum casting part fabricated from acrylonitrile butadiene styrene (ABS) and acrylate based material made from FDM and MJM respectively. The hollow RP pattern has been used directly to produce ceramic moulds. The feasibility of ceramic mould has been assessed in term of burnout ability and crack defect. Dimensional accuracies and surface roughness of the castings part have been observed in this investigation. Result shows thicker mould with proposed stuco procedure resulted without any crack defect for botRP part and no residual ash remained when firing higher than 870°C of temperature.In addition, FDM produced better accuracy for overall mould thickness, but MJM have better surface roughness. Therefore both direct RP pattern were suitable to be used in IC process with proposed shell thickness.

Abstract: Estimation of the life cycle cost (LCC) for a hydrogen internal combustion engine (H₂ICE) that uses hydrogen as an alternative fuel by forecasting a financial investment plan for a period of five years (n = 5). This is influenced by the interest rate of 10% (i = 10). The effect of Annual Operating Cost and salvage value in the LCC for H₂ICE would give impact on the cost of investment and economic growth in the long term. The result shows the brake specific fuel consumption to achieve 14% savings for grams per kilowatt hour for the engine (G + H₂) compared to the engine (G). The operation of H₂ICE in the first year would be increased by 22%, the reason is due to the cost of equipment, maintenance and purchase of new components. However, the percentage of operation cost for the following five to ten year of Present worth (PW) is reduced to 0.36% in the fourth year (n = 4) within the interest rate of 10%. The return of initial investment in the capital-first cost (FC) is to occur at the beginning of the fifth year (n = 5) of H₂ICE operations. The cost of savings for the next five years would become more profitable reaching 37% reduction in cost compared to conventional fuel consumption

Abstract: Polymer membranes from renewable material with controlled pore size and structure were produce using phase inversion technique. The optimal conditions for the preparation of polymer membranes was polymer concentrations in N,N-dimethylformamide (DMF) solution 12 % (w/v), 15 % (w/v), 18 % (w/v) and 21 % (w/v). This is due to the types of structure; pinhole-like structure and interconnected network structure. The structure of the membranes consisted of thick fibrill elements. The polymer membrane cross-section is composed of stacks of separate layers. Permeability of the polymer membranes obtained at lower concentrations, gives highest value of 0.161, 0.015, 0.001 and 0.00051 L/s.m³ for 12 %, 15 %, 18 % and 21 % (w/v) respectively. Evidently, as the concentration of the polymer in DMF increases, the tear strength decreases. Meanwhile, for lower concentration in N,N-dimethylformamide (DMF), gave highest strength due to low membranes wall thicker. Thus, the membranes are easily break compared to the membranes that have high porosity as shown by tear test of 12 % with 21.8495 N/mm tear strength.

Abstract: This paper presents numerical investigations of the thermal and fluid flow behavior in an L-shaped of cavity filled with nanofluid. The left and bottom walls are heated to higher temperature than the horizontal upper and right vertical walls. The results show that the characteristic of flow and heat transfer are critically dependent on the dimensionless Rayleigh number. We also found that the presence of nanoparticle enhances the heat transfer rate in the enclosure.

Abstract: The flow around surface-mounted cube under neutral atmospheric boundary layer was simulated using two-equation turbulence models. The accuracy of two-equation turbulence models to model the flow fields were compared against fully documented experimental data. To build low computational cost, mesh refinements were investigated through mesh independence study by means of standard wall functions for the near wall treatment. All the two-equations turbulence models are shown to be underpredict the separation length and overpredict the reattachment length near the cube wall. In particular, the standard k-ε turbulent scheme shows good agreement with experimental data of streamwise velocity flow along the symmetry plane behind the cube.

Abstract: As demand for clean and healthy environment, people make many alternate solutions to save the environment. To save trees and overcome landfill of waste material and waste disposal by burning activities issues (cause to losing energy and increase pollution), people nowadays take recycling as a recovery. Recycling waste paper into new product increased over the years. Shortage of wood supply required new sources of natural fiber for papermaking industry. Many researchers have studied new sources of natural fibers from non wood materials, such as oil palm residues, kenaf (Hibiscus Cannabinus), pineapple leaf, banana, and coconut fiber. Kenaf is choose as reinforcement agent for recycled waste paper to maximize the use of kenaf in industry application due its wide range of advantages where pineapple leaf are choose as reinforcement agent because abundantly of these material in Malaysia. Reinforcement of natural fiber into waste paper during recycling process expected to increased strength properties of final product. To understand the right and suitable processing method for kenaf fiber and pineapple leaf leaves previous work from other researchers are studied to investigate pulping procedure of natural fiber and its effect on mechanical strength.

Abstract: Bio-monomer based on original cooking oil was mixed with the hardeners with different percentages of Waste granulate Biopolymer (WB) fillers which is 30, 40, and 50 % equivalent to weight of monomer to produce Biopolymer filled Waste granulate Biopolymer (BWB) by using hot compress moulding. The tensile strength of BWB is 0.33, 0.45 and 0.43 MPa, meanwhile value of Youngs Modulus is 11.00, 8.18 and 5.06 MPa for loading 30, 40 and 50 % respectively. From the Scanning Electron Microscopy (SEM) micrograph, BWB has two characteristic and classified as a brittle and ductile fracture of granular (shiny) texture or cleavage character with little yielding before the sample breaks. Furthermore brittle fracture is characteristic by rapid crack propagation and then ductile fracture with stress whitening zone, appears fibrous appearance is dull and it have very rough surface. This fracture has glassy smooth surface, flat, bright, shiny and minimum deformation.

Abstract: This paper presents outcomes of the usage of a developed prototype of PFI retrofit-kit for small 4-stroke gasoline engine. The developed PFI retrofit-kit produced good and high brake power and brake mean effective pressure compared to the carburetor system with over 50% improvement. Exhaust-out emissions such as carbon monoxide, carbon dioxide and hydrocarbon have been reduced in the range of 39%, 185%, and 57% respectively. However, brake specific fuel consumption was found to be higher (125%) as compared to carburetor system.

Abstract: Line profile is an important consideration in printing functional devices particularly in printing very fine line for electronic applications. Since laser machining provides the opportunity to apply extreme fine lines with different profiles where unachievable mechanically. Laser ablated printing plate are costly to produce, hence it is appropriate to investigate this within a computational framework beforehand. Therefore several designs will be investigated with different geometry as the variables using both linear elastic and non linear hyperelastic models. The results exhibits that finite element analysis serves appropriately as an exploration tool where it worked well with experimental results.