Behavior of biodegradable oil under impulse voltages

The properties of Palm Oil (PO) and Coconut Oil (CO) offer the potential for transformers with non-toxicity, high fire and flash points and better environmental compatibility while compared with those filled with Mineral Oil (MO). This potential has led to intensive studies of electrical performance of biodegradable oil especially in evaluating the electrical performance under lightning impulse voltage in recent years. This paper presents the investigation on the impulse breakdown voltage of PO and CO in such a uniform field. The PO used in this study is Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein type. Two testing methods, rising-voltage and up-and-down are considered for both oils with different gap distances (2.0 mm and 3.8 mm). Testing methods including rising-voltage method and up-and-down method have no notable influence on the breakdown voltages of RBDPOs and CO compared to MO.IntroductionThe majority of transformers in the power system network are oil filled type. The main functions of the oil used in a transformer are to act as electrical insulation, cooling medium and information carrier. Up to now, the main oil insulation used in a transformer is Mineral Oil (MO) since it is proven to be successfully applied in practice for many years. Natural and synthetic esters are considered as the alternative for conventional MO due to the high fire safety and environmental friendliness. Extensive studies were conducted looking into the chemical, physical and electrical properties of natural and synthetic esters [1-3]. Another possible alternative for ester based oils are Palm Oil (PO) and Coconut Oil (CO). PO is derived from palm kernel which can be further separated to produce Crude Palm Oil (CPO) and Crude Palm Kernel Oil (CPKO) [4-5]. Further processing of CPO can produced Refined, Bleaching and Deodorized Palm Oil (RBDPO). The most common PO considered for transformers application is RBDPO. On the other hand, CO is extracted from kernel of matured coconut palm. The CO can be further processed to produce a neutralized, bleached and deodorized CO and is currently the type of oil investigated for the transformers’ application [6]. Transformer in service shall be exposed to voltages in excess of the normal operating voltage, such as transient overvoltage due to lightning impulse or switching impulse. Therefore the increasing interests among researchers press for comprehensive investigations on electrical performance of these liquids especially under impulse voltage [7]. This paper presents breakdown strengths of biodegradable oils (RBDPOs and CO) and MO in a uniform sphere-sphere electrode under impulse voltages. The influences of voltage polarities (positive and negative) and testing methods (rising-voltage and up-and-down) on the breakdown behavior are investigated

Study of tensile properties for aluminum 6061 reinforced with AISI 1060 steel machining chips

The present study focuses on the tensile properties of Aluminum 6061 reinforced with AISI1060 Steel machining chips. Three different types of samples of aluminium 6061 reinforced with AISI 1060 steel machining chips were prepared using stir casting. The tensile test was conducted using universal test machine (UTM) for fabricated composites to study the tensile properties of aluminium 6061 reinforced with steel machining chips AISI 1060.The samples were prepared with different composition of AISI 1060 steel machining chip of 5%, 10% and 15% according to the weight fraction of parameter variable. Two casting processes were applied in this project namely stir casting and sand casting process. The stir casting was used to mix the two different metals to become a composite at temperature between 750℃ to 800℃ in a furnace while sand casting was used to fabricate the samples into ASTM-E8M standard for tensile testing. The results showed that the samples with higher reinforcement percentages of steel machining (15%) showed higher tensile stress and higher modulus value characteristic compared to other samples. The experiment proved that the reinforcement material has good mechanical properties compared to the pure material

Accuracy and quickness criterion-based driving skill metric for human adaptive mechatronics system

Previous studies on driving skill algorithm have combined tracking error and time related variables into algorithm formulation. This method however does not include a car orientation and lateral speed information as an integral part of the algorithm. Two new variables are introduced into the algorithm structure, namely, orientation angle and lateral speed. Nine participants were carefully recruited for a driving test to validate the algorithm. A simulated driving environment was specifically devised for this experiment. A driving track used in this experiment was segmented into five different severities for data analysis. Two fundamental goals have led to the collection and subsequent analysis of the data. The first is analysing the variables in relation to the driving task. The second involves data analysis being further extended into analysing the algorithm performance over estimating the driving skill index. The results reveal that the proposed variables are well correlated with the driving task, and improvement in algorithm performance is found to be almost double compared to the previous algorithm

Water Absorption And Tensile Properties Of Kenaf Bast Fiber- Plasticized Poly(Lactic Acid) Biocomposites.

Abstract - Increasing awareness on the environmental safety coupled with new rules and regulations has forced manufacturers to consider biodegradable materials for their products.The aim of this work was to investigate tensile properties and water absorption behavior of biocomposites from kenaf bast fiber and poly(lactic acid).The composites were prepared by Haake internal mixer and compression molding

Aerodynamics characteristics around simplified high speed train model under the effect of crosswinds

The aerodynamics problems of train commonly come when the flow pass through train body. The increasing speed of train to achieve highly technology demands has led to increase the forces and moments and increase sensitivity of train stability and may cause the train to overturn. In this paper, two prisms arranged in tandem represent a simplified model of high speed train are performed at different yaw angle ranging from 0° to 90° by using the unsteady Reynolds- Averaged Navier Stokes (URANS) equation combined with k-ω SST turbulence model. The Reynolds number is 3.14x105based on height of the train and the free stream velocity. The aerodynamic quantities such as the side force, lift force and drag force coefficient show a similar trend where the forces increase with the yaw angle until a certain critical yaw angle before start to decrease till the yaw angle of 90°. The flow structure around the train under the effect of crosswind is visualized. The vorticiticy start to form from the nose and slowly drifts away further towards the trailing edge. The two-dimensional mean streamlines on the cross-section of train at different yaw angle show that the size of vortex increase as the yaw angle increase. Time averaged pressure contour plotted on the cross section along x-axis show the variation of region between high pressure and low pressure region on the leeward and windward side of the train model that may cause train to overturn. © 2006-2017 Asian Research Publishing Network (ARPN)

Aerodynamics characteristics around simplified high speed train model under the effect of crosswinds

The aerodynamics problems of train commonly come when the flow pass through train body. The increasing speed of train to achieve highly technology demands has led to increase the forces and moments and increase sensitivity of train stability and may cause the train to overturn. In this paper, two prisms arranged in tandem represent a simplified model of high speed train are performed at different yaw angle ranging from 0° to 90° by using the unsteady Reynolds- Averaged Navier Stokes (URANS) equation combined with k-ω SST turbulence model. The Reynolds number is 3.14x105based on height of the train and the free stream velocity. The aerodynamic quantities such as the side force, lift force and drag force coefficient show a similar trend where the forces increase with the yaw angle until a certain critical yaw angle before start to decrease till the yaw angle of 90°. The flow structure around the train under the effect of crosswind is visualized. The vorticiticy start to form from the nose and slowly drifts away further towards the trailing edge. The two-dimensional mean streamlines on the cross-section of train at different yaw angle show that the size of vortex increase as the yaw angle increase. Time averaged pressure contour plotted on the cross section along x-axis show the variation of region between high pressure and low pressure region on the leeward and windward side of the train model that may cause train to overturn. © 2006-2017 Asian Research Publishing Network (ARPN)

Aerodynamic characteristics of a cranked planform blended wing-body aircraft with 40° sweep angle

Baseline 7 Blended Wing-Body design is introduced to study the behaviour of the control surfaces, given four elevons without vertical stabilizer and wingtip. The objective of the paper is to obtain an aerodynamic characteristic of a cranked planform blended wing-body aircraft. The airfoil used for the entire body is NACA 2412, which is selected for ease of fabrication process. The wingspan of the model is 1.4 m with 0.2 m thickness. The sweep angle of the model is fixed to 40°. The wingspan area is calculated at 0.405 m2. The experiment is conducted at UTM-LST Wind Tunnel, AEROLAB, Skudai, Johor with test wind speed of 15 m/s. The maximum lift-to-drag ratio for the model is found to be around 21.9, which is better than many conventional aircraft. Nonetheless, the parabolic regression made to the drag versus lift plot only yields maximum lift-to-drag ratio of 10.0. The value of drag coefficient at zero lift is 0.012 while the maximum lift coefficient found is at 0.65 at 15° angle of attack. The lift-to-drag ratio improves 38.3% from 15.9 in the previously-published design. The neutral point is found to be located at 30.6% of the mean geometric chord in front of the wind tunnel model reference center or about 0.398 m from the nose of the 0.63 m long aircraft model or at 63.1% of aircraft length from the nose

The mechanical performance of sugar palm fibres (Ijuk) reinforced phenolic composites

Sugar palm fibres are one of the natural fibres which have many features and need further study to understand their properties. The aim of this work is to investigate the flexural, compressive and impact properties of sugar palm fibres reinforced phenolic composites. Sugar palm fibres were used as a filler (particle size 150 μm) and with loading of 0, 10, 20, 30, and 40 vol.%. The fibres were treated by sea water and then fabricated into composites by hot press technique. Flexural, compressive, and impact tests were carried out as per ASTM D790, ASTM D695-08a, and ASTM D256 standards, respectively. Scanning electron microscopy (SEM) was used to investigate the morphology and the interfacial bonding of the fibres-matrix in composites. The results show that the mechanical properties of the composites improve with the incorporation of fibres. The composite of 30 vol.% particle loading exhibit optimum values which are 32.23 MPa, 61.66 MPa, and 4.12 kJ/m2 for flexural, compressive, and impact strength, respectively. This was because good compatibility of fibre-matrix bonding. Consequently, sugar palm fibre is one of the prospective fibres and could be used as a potential resource to reinforcement polymer composite

Preparation and Properties of Clay-Reinforced Epoxy Nanocomposites

The clay-reinforced epoxy nanocomposite was prepared by the polymerization method. The effect of clay addition on the mechanical properties of epoxy/clay nanocomposites was studied through tensile, flexural, impact strength, and fracture toughness tests. The morphology and tribology behavior of epoxy/clay nanocomposites were determined by X-ray diffraction (XRD) and wear test, respectively. The wear test was performed to determine the specific abrasion of the nanocomposites. In addition, the water absorption characteristic of the nanocomposites was also investigated in this study. XRD analysis indicated that the exfoliation structure was observed in the epoxy nanocomposites with 3 wt% of clay, while the intercalated structure was shown at 6 wt% of clay. It was found that the addition of clay up to 3 wt% increased the tensile strength, flexural strength, impact strength, and the fracture toughness. On the contrary, the presence of above 3 wt% of clay produced a reverse effect. It could be concluded that the best properties in mechanical, wear resistance, and water resistance were obtained for the epoxy nanocomposites containing 3 wt% of clay

LIFE EXTENSION TECHNIQUE FOR WELDED STRUCTURE USING HFMI/PIT: A REVIEW ON PAST AND CURRENT RESEARCHES WITH APPLICATIONS

In this paper, High Frequency Mechanical Impact (HFMI) using Pneumatic Impact Treatment (PIT) which can be applied for new or aging welded structure towards asset integrity will be discussed. The technology HFMI/PIT which falls under post weld treatment process is primarily aimed to enhance fatigue life and to strengthen welded joint. At first, the basic principle on fatigue of welded structure based on the IIW Recommendation will be briefly described. Further, various investigations conducted by prominent research universities or institutions and various industrial applications in European countries will be reviewed and discussed. Lastly, the current research on application of HFMI/PIT carried out under Advanced Manufacturing Technology Excellence Centre (AMTEx) at Faculty of Mechanical Engineering UiTM Shah Alam will be presented. As conclusion, it is stated that HFMI/PIT can be applied for extending the structural life and also for design optimization