International Journal of Integrated Engineering
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Effect of Titanium Dioxide on Material Properties for Renewable Rapeseed and Sunflower Polyurethane
Full text linkPolyurethanes (PUs) have been synthesised successfully from renewable resources namely as rapeseed and sunflower oil using 4,4’-methylen-bis-(phenylisocyanate) (MDI) as the cross-linking agent. The mechanical property of these materials was observed in the Dynamic Mechanical Thermal Analysis (DMTA) test. A high tan delta peak is essential for a good damping material. These PUs can be strongly influenced on the addition of small (2.5-10) percentages of titanium dioxide, TiO2, e.g. the damping was improved on adding TiO2. Upon UV-induced aging, two important changes occur as observed in mechanical damping, such as a decrease in the height of the tan delta peak and a shift of the temperature of the tan delta peak to higher values with increased irradiation time. The loss tan delta peaks for the rapeseed-based PU loaded with 2.5, 5, 7.5, 10% of TiO2 were 0.58, 0.6, 0.68, and 0.71 respectively as compared with neat RSPU at only 0.43. These data show that the damping ability is enhanced through the introduction of TiO2 into the polymer. By doping with TiO2, the mechanical or physical properties of these PUs can be altered systematically, such as to get progressive increases in its stiffness and damping property
Modelling Thermal Environmental Performance In Top-lit Malaysian Atrium Using Computational Fluid Dynamics (CFD)
Full text linkComputational Fluid Dynamics (CFD) programs are powerful design tools that can predict detailed flow movement, temperature distribution, and contaminant dispersion. This paper reports the steady-state 3-D CFD modelling of air movement and temperature distribution due to thermal buoyancy within top-lit three-storey representative Malaysian atrium forms using the computer code PHOENICS. Details of temperature distribution, airflow patterns and other comfort parameters would provide a better picture of the resultant thermal performance within the atrium in response to the changes of design variables. The CFD modelling studies were to investigate quantitatively the effects of varying inlet to outlet opening area ratios and also the outlet’s arrangement on the atrium’s thermal environmental performance in relation to occupants’ thermal comfort. The simulation results have revealed that sufficiently higher inlet to outlet opening area ratio (i.e. n>1) can improve the thermal performance on the occupied levels; while with an equal inlet to outlet opening area ratio (i.e. n=1), changing the outlet’s arrangement (i.e. location and configuration) has not significantly affected the atrium’s thermal performance
Investigation of Surface Roughness and Material Removal Rate (MRR) on Tool Steel Using Brass and Copper Electrode for Electrical Discharge Grinding (EDG) Process
Full text linkThis paper presents the investigation on surface roughness and material removal rate (MRR) of tool steel machined with brass and copper electrode for Electrical Discharge Grinding (EDG) process. The machining parameter include pulse ON time, pulse OFF time, peak current and capacitance. Analysis of variance (ANOVA) with Taguchi method is used to investigate the significant effect on the performance characteristic and the optimal cutting parameters of EDG. The result shows that, the surface roughness value when using of both tool materials are mostly influenced by pulse ON time and peak current. The capacitance parameter in both experiments was not giving any significant effect. The significant factors for the material removal rate due to the machining parameter are peak current parameter and ON time parameter but it also can increase the machining tim
Evaluation of Hybrid Membrane Bioreactor (MBR) For Palm Oil Mill Effluent (POME) Treatment
Full text linkThe pollution load of palm oil mill effluent (POME) is in the range of 50,000 mg COD/L. With more than 500 palm oil mills, Malaysia produces some 13.9 million tonnes of crude palm oil annually and generates around 35 x 106 m3 POME. Typically, raw POME is difficult to degrade because it contains significant amounts of oil (tryacylglycerols) and degradative products such as di-and monoacylglycerols and fatty acids. The fatty acids composition (C12 – C20) of each of this fraction are different from one another and contribute to the high value of pollution load in POME. Thus POME has to be treated, usually in a series of anaerobic and aerobic treatment steps, for the organic matter to be degraded before the effluent is allowed to be discharged into public waterways. The objective of this study was to observe the performance of a hybrid membrane bioreactor (MBR) for POME. The raw POME was introduced into sequencing processes of anaerobic, anoxic and aerobic in order to achieve biological nutrient removal and the membrane modules were submerged into the aerobic zone. The critical flux of MBR using the flux-step method based on transmembrane pressure (TMP) was conducted as well as flux and permeability studies for assessing fouling in a membrane bioreactor operating at constant flux. The reactor was operated at a mixed liquor suspended solid (MLSS) concentration of 4000 to 8000 mg/l. The removal efficiency of COD, SS, TN and TP achieved were 94%, 98%, 83% and 64% respectively. The hybrid MBR was found to be able to degrade POME significantly and high quality effluent could be reused for various other applications.Keywords
Design of FPGA- Based SPWM Single Phase Full-Bridge Inverter
Full text linkNowadays power inverters serve as an important emergency power supply system in events of main power supply failure. The AC output voltage of a power electronic inverter is usually non-sinusoidal and hence has a high harmonic content. Sinusoidal Pulse Width Modulation (SPWM) scheme is normally used to convert the DC power supply into AC power supply by comparing the reference voltage waveform with the triangular waveform known as carrier. SPWM provides a way to reduce the total harmonic distortion of load current. The objective of this paper is to demonstrate a SPWM switching scheme by using Altera DE2-70 board. In this SPWM technique, a sinusoidal reference voltage waveform is compared with the triangular carrier voltage to generate the on and off switching states. This switching scheme will trigger the gate of the power switch. In this paper, the SPWM switching strategies implemented using Altera DE2-70 (Cyclone II EP2C35F672C6) with 16 bit serial configuration devices. The switching between reference and carrier waveforms of SPWM is obtained by using Matlab software. Simulation on the design waveform is conducted using Quartus II software tools provided by Altera. The output frequency of SPWM is 50 Hz and the design is limited to two values of modulation indices which are 0.5 and 0.75
Finite Element Simulation on Damage and Fracture Properties of a Ring Cut from Filament-Wound Pipes with and without Delamination
Full text linkThe technological advances in various industries have increased the demands on new engineered material tremendously since conventional materials such as steel, failed to perform in severe conditions. Nowadays, composite materials especially fibre-reinforced plastic composites (FRP) are broadly being used in many engineering fields to manufacture critical components with high stress concentration, exposure to extreme surrounding or weight constraint. However, they often suffer from a characteristic weakness, i.e. they are prone to interlaminar damage, often in a form delamination. In order to assess the development and the consequences of such damage, interlaminar fracture properties are essential. In this study, the ring cut specimen from filament-wound pipes with and without delamination was modelled and simulated based on experimental work using finite element modelling to further assist the identification and determination of the fracture properties. Investigation also involves the effect of the delamination length to the Energy Release Rate, G. Comparison between 23mm delamination of simulation and experimental results from [7] is presented
Analysis of Concentric Split Ring Square Element for Broadband Reflectarray Antenna
Full text linkAn investigation of phase variation and phase range of concentric split ring square element for broadband reflectarray antenna is presented in this paper. This is realized by exploiting the physical geometry of three element shapes namely square element, concentric ring square element and concentric split ring square element. Modifying the current distribution of basic concentric ring square element, leads to a less steep phase variation and also the bandwidth performance. An analysis of frequency response is described and analysed. The physical interpretation of the elements is also discussed. The proposed antenna element effectively covers two frequency operations (13.44 GHz and 18.36 GHz) in Ku-band range. Bandwidth broadening is achieved by introducing the ring square combination of element and the practical phase range is achieved through the use of RF 35 (thickness = 1.524 mm) as the substrate. The new concept of split initiates to a wider bandwidth (up to 67.6 %) for the antenna and can applied to any two frequency operations of Ku-band applications
Finite Element Simulation on Crack Analysis of a Thick-Tube
Full text linkMost engineering failure began with cracks. Crack may caused by material defect, discontinuities in geometry or damage in service. Thus, Fracture Mechanics is introduced as a method for predicting failure of a surface containing a crack. This project is focusing on pre-existing crack with assumption that no microscopic defects are presents. Linear Elastic Fracture Mechanics (LEFM) is used to evaluate the Stress Intensity Factor (SIF) of the specimen. Further analysis is done by incorporating Elastic Plastic Fracture Mechanics (EPFM) to understand the crack growth over period of time. In this study, the important parameters in fracture mechanics such as Stress Intensity Factor (SIF), Crack Mouth Opening Displacement (CMOD), J Integral and stable crack growth are been investigated. A complex loading simulation of NKS-3 specimen is done using finite element modeling. The NKS-3 is a thick-tube used in Pressurized Water Reactor (PWR) which has a circumferential flaw on its inner surface. The cylinder is loaded with axial tensile load and internal pressure combined with thermal shock. A 2-Dimensional Axysimmetric-4 nodes element with focused mesh at the crack tip is employed in the simulation. Several analyses have been done using hardening data at different temperature. A comparison of solution is made for simulation with and without thermal load history. Further analysis showed that the stable crack growth is estimated to be around 3.0mm
Modelling Thermal Stratification in Atrium Using TAS Program and Verification of Prediction Results
Full text linkThis paper reports the TAS computer simulation of the three-storey atrium in Southern China. It was an attempt to correctly model thermal stratification of a large multi-level space within the atrium using TAS program. The prediction results of modelling with blinds and without water spray, particularly indoor air and mean radiant temperatures, and roof blind surface temperature, were compared and verified with the results from the site measurement to evaluate the capability and accuracy of the developed TAS model in simulating atrium’s indoor thermal environmental performance. The simulation results have shown that TAS program tends to overestimate its prediction results. For hot and overcast day simulation, the difference in air temperature over the 24 hours between measured and predicted is in the range of 0.1 K to 1.8 K on the first floor and 0.2 K to 4.3 K on the second floor respectively. Whereas for hot and clear day simulation, the difference is in the range of 0.1 K to 1.5 K on the first floor and 0.1 K to 2.7 K on the second floor respectively. Despite moderate discrepancies between the measured and predicted results, it is evident from the study that the created TAS model is capable to model thermal stratification within multi-level atrium, with reasonably accurate results