Abstract: This research deals with natural convection heat transfer from vertical heated cladded plates, which are symmetrically placed in proposed chimneys of variable heights in the core of a typical MTR reactor. The heated plates serve as thermal pumps for pumping fluid of a symmetrical enclosure beneath the chimney. The suggested chimneys are used for increasing the length of the vertical heated channels of the reactor core to give the chimney effect. In the thermal analysis of natural convection in channel–chimney systems, the variables that play an important role are heat flux, maximum wall temperatures and geometrical parameters such as the height of the heated channel, the channel spacing and the height and spacing of unheated extensions. A simple numerical procedure to obtain the thermal design charts, a thermal optimization of the system and an uncertainty analysis due to the thermo- physical properties is presented. The present results are obtained from a real domain inside the reactor core data in the following dimensionless parameter ranges: 5≤ Lh/ b≤ 20; 1:5≤ L/Lh ≤ 4; 1≤ B/b≤ 4; 102 ≤ Ra≤ 105 . This study results in enhancing the reactor power in the free convection regime from a maximum of 400 kW up to 950 kW of thermal energy. This is quite significant increase in reactor power in the natural convection regime which adds to reactor safety. The results are of importance to reactor operation and safety in the natural convection mode of operation.

Abstract: The present study deals with natural convection flow coupled with surface radiation in a vertical open-ended channel with wall constant heat flux. The experimental and numerical investigations are both conducted using air as the working fluid. The numerical code is developed using finite differences scheme to solve the Navier-Stokes equations under the Boussinesq assumption in two dimension. Surface radiation heat transfer is taken into account by using the radiosity method. Concerning the experimental apparatus, it consists of a vertical channel heated uniformly on one wall while the other is isolated. Temperature and velocity measurement are provided for two modified Rayleigh numbers Ra=3.9 105, 9.1 105. The numerical code is first validated with previous numerical investigations. Then, comparison between experimental and numerical results is performed with and without surface radiation and discrepancies on temperature and velocity profiles are discussed. It was found that surface radiation play a significant role in the evolution of the dynamical and thermal behaviour of the natural convection flow inside the channel.

Abstract: Buckling behavior of composite plate taking into account the effect of natural sisal fiber reinforcement is presented in this work. Investigating the buckling load of composite plate was done using both experimental and theoretical (including analytical and numerical) techniques. The composite plate specimens examined was reinforced with various volume fractions of natural sisal fiber. Furthermore, the composite plate was supported with different boundary conditions. The experimental and analytical data obtained for the buckling load are further supported with numerical data evaluated using the finite element method by ANSYS 14.0 commercial code. In the experimental method, the samples of the tensile test composite as well as the buckling plate are firstly manufactured. Then, the modulus of elasticity for the samples of composite plate with tensile test was evaluated, while the buckling load of plate was evaluated by the buckling test of composite plate. The results of buckling plate reveal that the reinforcement of natural sisal fibers leads to increasing the plate stiffness, and hence, causes an increase in the buckling load of composite plate. Moreover, a comparison was conducted between the data obtained for the buckling load, where a good agreement was found. The maximum error found between the results obtained experimentally and those estimated theoretically was about (12.28%), while it was about (3.9%) between the analytical and numerical predictions.

Abstract: This study aims to examine the uniaxial and biaxial ratchetting responses of glass fibre reinforced epoxy (GRE) composite by experiment and finite element (FE) analysis. The uniaxial ratchetting of GRE composite laminate was tested under cyclic axial stress with a constant mean stress of 40 MPa and an amplitude stress between 26.67 MPa and 53.33 MPa. The biaxial ratchetting test was also performed on 50 mm diameter of GRE composite straight pipe. The GRE pipe was subjected to a constant internal pressure of 1.875 MPa and 1% of cyclic axial strain. The FE models were simulated using Abaqus in similar loading cases. The uniaxial ratchetting strain was found to increase with the number of cycles, but the ratchetting strain rate was decreased. The specimen showed no further ratchetting and exhibited shakedown after some strain accumulation. On the basis of the experiment and simulation in the biaxial test, it appears that ratchetting would occur in the hoop direction for a GRE pipe with no ratchetting observed in the axial direction. The results showed that the FE analysis over-predicts the ratchetting rate for uniaxial ratchetting test as compared to the experimental values, but under-predicts in the biaxial ratchetting test at initial cycles.

Abstract: There is heavy dependence on fossil fuels for energy production. These are not only depletable but also are the main cause of emissions and global warming. Renewable energy and biofuels can play significant role in this concern. This research is concerned with the efficient production of biodiesel from Jatropha seeds. We designed and operated an efficient screw press for continuous production of biodiesel. The effects of many parameters which affect the oil yield from the press were studied in order to determine the optimum operating conditions for maximum yield. The objective of this paper is to obtain the optimum speed and preheating temperature of our screw press to get improved properties of extraction oil, minimum extraction time and minimum motor power. The present screw press is specially designed on laboratory scale. The influence of different motors speeds of 20, 60, 100 and 140 rpm and preheating temperatures 50, 75, 100 and 125 °C on oil extraction yield were investigated. The results show that extraction Jatropha oil by screw press is more efficient in producing Jatropha yield than other methods. There is a limiting minimum extraction temperature for reducing free fatty acid percentage in the produced oil. An extraction temperature of 75 or 100 °C at motor speed of 20 or 60 rpm give the maximum Jatropha extraction yield. These conditions also are related to low motor power and torque.

Abstract: The goals of this paper are to recognition the butt welding joint for welding robot environments by using a new approach of background subtraction seam path process. Butt welding joint images were captured from CCD camera mounted on the top of the work bench then processed by the proposed approach method to extract and determine the weld seam path position in x-y coordinates. The image is segmented used Sobel filtering to determine amplitude images in access channel then subtract between the access channel and input images with different threshold values to find the region of edges joint. Next process is to apply morphological technique, fill up the hole to calculate the area, skeleton and generate the sub-pixels type of data (XLD) contour points. The position of the start, mid, end and auxiliary points of butt welding joint are selected according to contour points with the three case studies identification weld seams path process. The results, shows that the proposed method was capable to automatically detect and identify the butt welding joints in three case studies without any prior knowledge of the shapes. In terms of match error compared with the actual position, case study 2 had the lowest matching error which is less then ± 2 pixels either column or row. The highest match errors happened in case study 3 where the matching error is in the range of ± 11 pixels.

Abstract: In this paper the mathematical model of double flow flat plate and corrugated absorbers solar air heater having various configurations are presented. A computer program in C++ language has been developed to solve the mathematical model. The energy, effective and exergy performance of collectors are analyzed on the basis of effective parameters such as mass flow rate, insolation and flow channel depth. Comparison of present mathematical model results with the results of other researchers show a good agreement. The results of corrugated absorber have been compared with flat plate absorber solar air heater for similar operating conditions and its indicate that there is significant enhancement in efficiency of corrugated absorber to that of the flat plate absorber solar air heater with double flow configurations. It is observed that the exergy efficiency become negative at higher mass flow rate (i.e. m > 0.072 kg/s) for all types of solar air heater. The results also show that the optimum channel depth of AH-1 solar air heater is 0.02 m at which all efficiencies have the highest values for entire range of mass flow rate and insolation investigated.

Abstract: Running shoes have been continuously considered as a risk or solution to injury. Plantar fascia strain is always associated with common foot injury of runners. The aim of this study to evaluate the influence of barefoot and shod condition to temporal parameter and plantar fascia strain. This study analyzes temporal parameter, plantar fascia strain (PFS) and medial longitudinal arch (MLA) angle during the stance phase of 9 male subjects that running with barefoot (BF) or two shod conditions (cushioned heeled (HS) and minimally running shoes (MS)). Differences of the running conditions were analyzed using visual 3D software. The result showed there is no correlation between stance time and running condition. However, BF running revealed the highest PFS and peak medial longitudinal arch (MLA) angle during running on each surface. Thus, it seems that BF running has the highest possibility of injury compared to HS and MS with respect to plantar fascia.

Abstract: Ankle Foot Orthoses (AFO) are externally applied devices that control the foot and ankle joint complex. Comparing to traditional stand-alone medical devices, high-confidence medical cyber-physical systems have the great potential to transform the medical device industry through embedded software for local control and network connectivity for cloud computing and data mining techniques. The goal of this research is to implement cyber-physical systems approach to create wireless and web-based control for a prototype soft AFO powered by artificial pneumatic muscles to aid walking in patients with ankle and foot injuries. Ultimately, this research aims to apply the many sensor measurements of smartphone devices, such as accelerometers, gyroscopes, GPS and stream of Internet connection to connect wirelessly to the prototype AFO while giving the user control of the AFO's parameters. It will also be able to synchronize multiple streams of data over the Internet to the patient's physician. Furthermore, it could grant the physician remote access to reconfigure the AFO without being physically present with the patient, thus reducing healthcare cost.

Abstract: Global demand for natural fiber polymer composites has increased due to the increase of population and new applications primarily in Malaysia today. Natural fiber polymer composites have been explored as alternatives by replacing wood fiber in producing various types of furniture that provide comfort with a practical strength and stability to fulfill society demand. The objective of this study is to investigate the effects of untreated and treated kenaf fiber (PP/KF) reinforcement on the flexural strength of Polypropylene. Flexural strengths of pure PP, 10%, and 20% of untreated KF by weight to PP have been recorded. In addition, flexural strengths of treated KF soaked with 5%, 10% and 20% of Sodium Hydroxide (NaOH) have also been recorded. PP/KF untreated and treated composites were melt blended and then injection molded for characterization to observe their flexural strengths by measuring their threshold. Three point bending test was carried out to determine the flexural stresses of the materials. The result show that treated specimen yields better flexural performance at 20% PP/KF compared to 10% and pure PP. Scanning Electron Microscopy (SEM) is used to observe the morphological characteristics of PP/KF. The good interfacial bonding between KF and PP is 5% NaOH due to the optimum strength of the structure. Overall 5% NaOH with 20% PP/KF show the best result compared to others with flexural stress value 3.25MPa.

Abstract: In this present investigation, the effect and optimization of machining parameters on the kerf width and surface roughness in wire electrical discharge machining (WEDM) operations of Al 60661 hybrid composite was studied. The hybrid metal matrix composite was fabricated by stir casting process using particulates SiC and graphite each in Al6061 alloy. The experiments were designed with L27 orthogonal array. The experimental studies were conducted under varying pulse on time, pulse off time, peak current, gap set voltage, wire feed rate and wire tension. The effect of the machining parameters on the kerf width and surface roughness (SR) is determined by using analysis of variance (ANOVA). A multi-response optimization, Taguchi-based grey relational analysis was used to find the optimal process parameter setting for the best quality machined characteristics. Confirmation test was conducted at selected optimal parameter levels, which shows improvement in grey relational grade, thus confirming the strength of grey relational analysis.

Abstract: In order to evaluate the performance of Minimum Quantity Lubrication (MQL) in cutting, it is necessary to understand the tribological and thermal effects of MQL during cutting process. This paper proposes a Finite Element Method to analyze the influence of the Minimum Quantity Lubrication in turning process of mild steel in terms of cutting force and cutting temperature. In the meantime, orthogonal cutting tests of medium steel JIS S45C is executed with the TiCN-coated cermet tool in order to obtain suitable parameter to verify the simulation model. Minimum quantity lubrication friction coefficient and chip thickness are obtained from the cutting experiment. Heat convection coefficients based on the MQL types are utilized in the proposed model. It is proven that the FEM is capable of estimating the cutting process with a good degree of accuracy. The model applied in the study enables to evaluate MQL assisted cutting characteristics in which cutting force and cutting temperature can be estimated.

Abstract: As a kind of clean production method, the application of laser processing is more and more common in the process of heat coating and heat treating. However, the laser heating processing may result in reduced precision of workpiece due to the residual thermal deformation. In order to ensure the precision of the workpiece after laser heating process, accurate estimation should be given for the control of the thermal deformation. In this study, a three-dimensional model of plate deformation under the action of pulse laser was constructed, and the deformation of Q345 steel plates of different thickness were simulated in the SYSWELD software, and then the deformation field distribution, mathematical model of plates’ warping angle under different laser parameters were obtained. The thermal deformation of the plate wrapping angle was estimated with the mathematical model, which provided a reference for plate deformation control during laser heating process.

Abstract: The Cart-Inverted Pendulum System (CIPS) is a classical benchmark control problem. Its dynamics resembles with that of many real world systems of interest like missile launchers, pendubots, human walking and segways and many more. The control of this system is challenging as it is highly unstable, highly non-linear, non-minimum phase system and underactuated. Furthermore, the physical constraints on the track position also pose complexity in its control design. This paper presents a control method to stabilise the unstable CIPS within the different physical constraints such as in track length and control voltage. A novel cartinverted pendulum model is proposed where mechanical transmission and a dc motor mathematical model have been included which resembles the real inverted pendulum. Therefore problems emerged in realtime implementation can be minimised. A systematic the state feedback design method by choosing weighting matrices key to the Linear Quadratic Regulator (LQR) design is presented. Simulation experiments have been conducted to verify the controller’s performances. From the obtained simulation and experiments it is seen that the proposed method can perform well stabilising the pendulum at the upright angle position while maintaining the cart at the desired position.

Abstract: Tube hydroforming process (THFP) is one of new forming techniques having many applications in the area of automotive and aerospace industries due to its capability to produce very complex tubular parts in a single step. The other advantages of THFP are improved structural strength and stiffness, lighter products and less material wastage. The main failures of THFP are bursting, buckling and wrinkling. These failures are to be avoided by proper selection of loading paths. The success rate of Hydroforming technique depends strongly on the selection of process parameter and the selection of loading path. From literature survey and trial experiments, it is found that internal pressure, axial feed & Length of the tube has major effect on the accuracy of the process. Therefore, the internal pressure, axial feed and length of the tube are taken as the influencing variables and the range of these variables are found by conducting trail experiments on Inconel 600 tubes. In consideration of the cost of process and materials, DOE (Design of experiments) is applied to minimize the total number of experiments required to complete the analysis with same accuracy. In continuation to that, the RSM (Response Surface Methodology) is applied to predict the mathematical models to estimate bulge ratio and thinning. Later the predicted models are utilized to optimize the tube hydroforming process.

Abstract: Flow inside the combustion chamber plays the main role in the combustion process. This paper analyzed the behavior of the flow inside the L-type combustion chamber for in-cylinder engine with three different simulations. The first simulation is dealing with the static geometry of the domain. There are only combustion chambers and piston volume involved in the static simulation. The air inlet velocity is calculated using the standard engine formula for the piston at position of 9°, 18°, 27°, 36°, and 45° degrees after the top dead center. Engine speed ranges from 1500 rpm to 4500 rpm with increment of 500 rpm. The second simulation called port-flow simulation also deals with the static geometry domain but there is an addition at the intake port and intake valve. The piston volume is set to be at highest volume. There are three different valve lift used. The inplanum pressure is set to the environment pressure and the outplanum pressure is set according to the chosen values.

Abstract: The paper employs finite element analysis approach to examine the effect of local material discontinuities of a percentage of the hoop length of unstiffened cone subjected to axial compression or external pressure. It is assumed that the finite element models are made from mild steel with geometry given by r2/r1 = 2.02, r2/t = 34.3, h/r2 = 1.01, β = 26.56º and t = 2.89 mm. The material was modeled as elastic perfectly plastic. Numerical results were obtained for the case of axial compression only and external pressure only using ABAQUS finite element code for two different sets, and they are: (i) free edge support at one ends to the whole circumference (at top and/or bottom), and (ii) non-continuous edge support at the top and/or bottom edges which are applied to a fraction of the circumference. For cones with non-continuous edge support, results indicate that for both cases crack extending by 10% of the circumference of the cones will cause a drastic reduction in its buckling strength. For axially compressed cones, about 57% reduction in the load carrying capacity. Whilst, for externally pressurized cones, about 24% reduction in the collapse load. Also, it appears from both cases that crack extending by 20% of the circumference of the cone is enough to cause maximum reduction in its buckling strength. This is purely numerical study but references to accompanying experimental work are provided.