Mechanical engineering

This paper presents an experimental investigation of a SMART scrubbing system in sugar processing plant. The objectives are to address the problem and develop new technique to increase the efficiency and eliminate sugar sludge production downstream of process line. The SMART scrubbing effect of water with the principal of dynamic precipitation was conducted on-site with calculated flow rate, which simulates the SMART scrubbing system. The on-site and scaled-down model experiments measure the upstream and downstream dust concentration and processes the flow rate of water required to counter the dust concentration based on the feedback flow. The investigation was conducted with a steady airflow of 6 m3/s with variation of water flow rates. The result of the on-site studies shows an excellent increase in average and maximum efficiencies of 98.77% and 99.3% respectively.

Amblyopia is the most commonly found monocular visual impairment in the world. This paper presents an initial investigation into developing a visual aid for monocular visual impaired patients. The investigations conducted in this paper include those from direct interviews from consultant ophthalmologist. Investigations include reviewing the principle required to be embedded into the visual aid such as the distance and depth perception. Stereoscopic cameras and algorithms are also further discussed to interlink with the concepts of depth perception. Monocular visual impairment can most of the time be caused by medical conditions like amblyopia or glaucoma, and rarely caused by accidents and external factors. Thus, existing treatments for amblyopia, the effectiveness and challenges of the treatment are also clearly investigated and scrutinized in this paper. Some of the existing treatments include refractive therapy, occlusion therapy, atropine injections, perceptual learning, pharmac...

Injection moulding is the most common technique of plastic forming. The industry is usually referred to as a MIMO (multi-input-multi-output) process that is basically involved with several input parameters (control factors) yielding almost inconsistent results on output variables (response factors). As a result of this, product quality is a major challenge in such unstable manufacturing environment. Taguchi methods (TMs) are commonly used in plastic injection molding industry (PIMI) as a robust optimization technique to serve for a wide range application from product design optimization to mould design and from optimal material selection to processing parameter optimization. This paper primarily aims at providing a comprehensive chronological review and classification on different applications of TMs in PIMI to serve for the following two purposes: first to present an evolutionary trend of TMs in PIMI and second for a comparative capability analysis of TMs in selected industrial-based case studies. Major pros and cons of TMs in will also be highlighted as compared to other optimization techniques rather than Taguchi Method.

Plastic injection molding is one of the most common methods of part manufacturing. Different optimization techniques are commonly used in this industry to satisfy for the multi-input multi-output (MIMO) characteristics of the injection process. The primary objective of this study is to provide a comparative Bibliometric analysis on injection molding process optimization during the previous decade based on the top seven methodologies found in the literature. Triple criteria of chronological trend, geographical dispersion and academic reputation are used for evaluating the overall performance of each method as well as each hybrid set. The survey will also include two complementary analyses for the Taguchi based methods. Firstly, a signal to noise ratio (SNR) analysis, followed by a secondary analysis of the average number of control and response factors as well as the orthogonal array levels used in the experimental design will be conducted. The results of the study reveal that Taguchi Method (TM), GA and RSM are the three most popular optimization techniques used in plastic injection molding worldwide. TM is also proved to be a better optimization tool when combined with other heuristic methods such as ANN and GA, especially in the field of product and mould design. For processing parameters, Taguchi still remains to be the core optimization technique.

For certain medical applications such as bone and teeth implant it is required to fabricate certain bio-composite materials that are compatible with natural human organs. This paper is primarily focused on the theoretical design and analysis of a set of two natural bio-composites made of Hydroxide Apatite (HA) as ceramic matrix. Two fillers of Titanium (TI) metallic powder and Polyamide 6 (PA 6)  will be used as reinforcements respectively. The analysis will be based on two mechanical and one physical property of the bio-composites including strength (σ) ,Young’s modulus (E) and composite density (ρ), at fibre volume fractions ranging from 0-50 % respectively, using two well-known comparative methodologies as Rules of Mixture (ROM) and Halpin-Tsai (HPTS) for each bio-composite independently.

All forecast-driven distribution channels are doomed to the intrinsic characteristic of an oscillating demand pattern leading to a progressively larger swing in inventory levels as moving upstream the supply chain. In supply chain management (SCM), this bullwhip effect is considered as one of the most critical factors that if not controlled appropriately can simply nullify all the efforts done by SCM experts to optimize the overall time and cost of delivering products and/or services.
As the number of intermediates between two extremes of the supply chain increases, monitoring and controlling of demand changes becomes even a more critical managerial issue. Based on Beer Game conceptual framework, in this paper, we will focus on a typical four-component supply chain including: factory, distributor, wholesaler, retailer to simulate and analyze the supply chain behavior during a 24 week period to monitor the system as well as components cost fluctuation trend due to bullwhip effect.

This paper is the second of a set describing the implementation and economic analysis of an improved solar photo voltaic (PV) system for Malaysian rural electrification. The work was carried out based on a case study in a rural community to replace their diesel-powered generators with the new renewable energy (RE) solutions, with buffer capacity for additional requirements. Based in the extensive tests done on the system, it is proven that the new improved design of solar power system can be implemented as it meets the technical requirements of the project.

This study is mainly to investigate the unsteady flows due to supercritical heat addition in high speed condensing steam in steam turbines. To achieve this, condensation flow characteristic is investigated on 2D converging-diverging nozzle. A Computational Fluid Dynamics (CFD) code (FLUENT package) that adopted the Eulerian-Eulerian approach for modeling wet steam flow, was used. The condensing flow is governed by the compressible Navier-Stokes equations in conjunction with a wet steam multiphase model. The turbulence model selected for this work is Spalart Allmaras model which is based on the Reynolds Averaged Navier Stoke (RANS) model available in FLUENT. Results are then compared with previous researchers that use different methods including user defined code and experiment. The importance of this research study is to determine the accuracy of the software and method used and to compare the results with other researchers.The current work shows good agreement with the experimental...

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This paper presents the design and development of a mini portable cooler that utilizes the Peltier effect to cool the human expressed breast milk (EBM) within 24 hours at the temperature range between 4°C-15°C to maintain the high quality of the EBM for use at a later date and the health of the baby who consume it. It is developed to overcome the tediousness of using cooler bag/box, which requires ice packs that need repetitive freezing. A few prototypes with different sizes and body materials, namely polystyrene, polypropylene and aluminium, were successfully developed and tested to get the minimum temperature using 5V power supply. In all graphs, the temperature is decreasing with time. The smallest size of the cooled space (18cm of width, 12cm of length and 14cm of height) has the lowest temperature compared to the other sizes for each body material. However, the lowest temperature of all body materials is obtained from aluminium with 11.2°C at 100 minutes. It also reaches below ...

This study is mainly to investigate the unsteady flows due to supercritical heat addition in high speed condensing steam in steam turbines. To achieve this, condensation flow characteristic is investigated on 2D converging-diverging nozzle. A Computational Fluid Dynamics (CFD) code (FLUENT package) that adopted the Eulerian-Eulerian approach for modeling wet steam flow, was used. The condensing flow is governed by the compressible Navier-Stokes equations in conjunction with a wet steam multiphase model. The turbulence model selected for this work is Spalart Allmaras model which is based on the Reynolds Averaged Navier Stoke (RANS) model available in FLUENT. Results are then compared with previous researchers that use different methods including user defined code and experiment. The importance of this research study is to determine the accuracy of the software and method used and to compare the results with other researchers.The current work shows good agreement with the experimental...

Computational Fluid Dynamics analysis on First Stage Nozzle in full scale multi-stage power station gas turbine has been carried out. The main aim is to investigate the turbine thermal performance when cooling rate decreases at certain level. All calculations were executed using commercial CFD code, ANSYS FLUENT which is able to accurately predict the flow and conjugate heat transfer problem as demonstrated in this investigation. The modelling of gas turbine nozzle is assisted by geometric cloud data obtained from 3D scan. Preliminary calculation shows that at the given worst case scenario for, the maximum thermal stress experienced by the component is within the maximum yield strength of the nozzle material. However, the safety margin between the predicted stress and maximum allowable stress is very small. 

The initial induced compressive residual stresses relax during component operating life and it is important to consider the relaxation phenomenon in the design of the component. In this study, 2024-T 351 aluminium alloy specimens were shot peened under three different shot-peening intensities. Cyclic tests for two load magnitudes were performed for 1, 2, 10, 1000 and 10,000 cycles. The initial and final residual stresses and the cold work after each loading cycle were measured for the three shot-peening intensities and for the two load magnitudes using X-ray diffraction. The initial and final microhardnesses after each loading cycle load were also measured for the three shot-peening intensities. The results showed that the reduction in the residual stress, microhardness and cold work are dependent on the applied load. An empirical model was proposed to estimate the residual stress relaxation. The presented model incorporates parameters including the degree of cold work, initial induced residual stress and the number of applied loading cycles.

This paper introduces the application of Taguchi optimization methodology in optimizing the cutting parameters of end-milling process for machining the halloysite nanotubes (HNTs) with aluminium reinforced epoxy hybrid composite material under dry condition. The machining parameters which are chosen to be evaluated in this study are the depth of cut (d), cutting speed (S) and feed rate (f). While, the response factors to be measured are the surface roughness of the machined composite surface and the cutting force. An orthogonal array of the Taguchi method was set-up and used to analyse the effect of the milling parameters on the surface roughness and cutting force. The result from this study shows that the application of the Taguchi method can determine the best combination of machining parameters that can provide the optimal machining response conditions which are the lowest surface roughness and lowest cutting force value. For the best surface finish, A1-B3-C3 (d = 0.4 mm, S = 1500 rpm, f = 60 mmpm) is found to be the optimized combination of levels for all the three control factors from the analysis. Meanwhile, the optimized combination of levels for all the three control factors from the analysis which provides the lowest cutting force was found to be A2-B2-C2 (d = 0.6 mm, S = 1000 rpm, f = 40 mmpm). ª 2013 Production and hosting by Elsevier B.V. on behalf Please cite this article in press as: J.S. Pang et al., Taguchi design optimization of machining parameters on the CNC end milling process of halloysite nanotube with aluminium reinforced epoxy matrix (HNT/Al/Ep) hybrid composite, HBRC Journal (2013), http://dx.

The initial induced compressive residual stresses relax during component operating life and it is important to consider the relaxation phenomenon in the design of the component. In this study, 2024-T 351 aluminium alloy specimens were shot peened under three different shot-peening intensities. Cyclic tests for two load magnitudes were performed for 1, 2, 10, 1000 and 10,000 cycles. The initial and final residual stresses and the cold work after each loading cycle were measured for the three shot-peening intensities and for the two load magnitudes using X-ray diffraction. The initial and final microhardnesses after each loading cycle load were also measured for the three shot-peening intensities. The results showed that the reduction in the residual stress, microhardness and cold work are dependent on the applied load. An empirical model was proposed to estimate the residual stress relaxation. The presented model incorporates parameters including the degree of cold work, initial induced residual stress and the number of applied loading cycles.