bluuebunny/crossref_metadata_2025 huggingface dataset:
Analytical and Experimental Study on Balancing Using Influence Coefficient Method
Authors: Mohamad Wan Sulaiman Wan , Mat Isa A.A. , Ismail M.A.
Published: September 2013

Unbalance effect on rotating element happens as a result of an off centered mass concentration which will generate centrifugal forces with increasing running speeds. This unwanted situation requires correction to avoid failure due to excessive vibration. In this study, unbalance problem are studied by using theoretical influence coefficient method followed by the experimental verification. Experimental procedure is performed by using trial mass to calculate the influence coefficient and the corrected mass values as well as the phase angles. Finally, the vibration reduction of the rotor is compared theoretically and experimentally. Based on the results, the improved vibration reduction could be obtained reasonably for both single and two-plane balancing by using influence coefficient method.
Ankle Joint Stiffness and Damping Pattern under Different Frequency of Translation Perturbation
Authors: Azaman Aizreena , Yamamoto Shin Ichiroh
Published: September 2013

The change of effective stiffness and damping characteristic of ankle joint are able to indicate degeneration of balance ability due to ageing effect. This paper will discuss the ankle joint stiffness and damping pattern along repeated translation perturbation. Six young healthy subjects were exposed to five trials of five different frequencies of perturbation (quiet standing, 0.2 Hz, 0.4 Hz, 0.6 Hz and 0.8 Hz). The result showed that the mean of effective stiffness was reduced with the increase of frequency applied; meanwhile the mean of damping value increased with increasing frequency. Additionally, a cubic polynomial curve (u-shape) was estimated to represent stiffness pattern when using curve fitting method with correlation R2>0.5. These estimations also suggested that ankle joint does not oscillate like spring-damper system which is based on inverted pendulum model; however, it applied a different strategy to maintain balance, in particular during initiation, middle and termination of perturbation. These also indicate the influence of sensory processing and adaptation to maintain balance under a long period of disturbance. On the other hand, damping pattern seems to be similar over different frequencies and under repeated perturbation. Besides, the change of stiffness pattern at higher frequency of perturbation (0.8 Hz) recommends the change in posture strategy from ankle to hip strategy. These findings indicated that stiffness and damping are able to describe adaptation of human posture strategy to keep balance and motor learning under repeated perturbation.
The CFD Simulation of Tray Dryer Design for Kenaf Core Drying
Authors: Misha Suhaimi , Mat Sohif , Ruslan Mohd Hafidz , Sopian Kamaruzzaman , Salleh Elias
Published: September 2013

Tray dryer is the most extensively use for kenaf core drying because of its simple and economic design. The product is spread out on trays at an acceptable thickness so that the product can be dried uniformly. Most tray dryers use hot air stream where water is vaporized from the product and removed by air stream. In a tray dryer, more products can be loaded as the trays are arranged at different levels. The drawback of this dryer is non-uniformity in the desired moisture content of end product. The key to the successful operation of the tray dryer is uniform airflow distribution over the trays. Therefore, the good design of the drying chamber configuration in a tray dryer is necessary to obtain optimum performance. This research is to design the uniform airflow distribution throughout the drying chamber using CFD simulation for kenaf core drying. Several configurations of drying chamber and trays position was designed and simulated to determine the tray dryer which can produce better airflow distribution. It was found that the design B gives a more uniform airflow distribution compared to others design. The good design of kenaf core dryer should be able to produce uniform drying at high drying capacity and shorter drying time.
CFD Analysis of Temperature Distribution in Can-Type Combustor Firing Synthetic Gas
Authors: Hasini Hasril , Shuaib Norshah Hafeez , Wan Abdullah Wan Ahmad Fahmi
Published: September 2013

This paper presents CFD analysis of the effect of syngas combustion in a full scale gas turbine combustor with specific emphasis given to the flame and flue gas temperature distribution. A base case solution was first established using conventional natural gas combustion. Actual operating boundary conditions such as swirl, diffusion and fuel mass flow were imposed on the model. The simulation result is validated with the flame temperature of typical natural gas combustion. Result from flow and combustion calculation shows reasonable trend of the swirl mixing effect. The maximum flame temperature was found to be the highest for syngas with the highest H2/CO ratio. However, the flue gas temperature was found to be approximately identical for all cases. The prediction of temperature distribution in the combustor would enable further estimation of pollutant species such as CO2 and NOx in complex regions within the combustor.
Flow Characteristics of a Servco Fume Cupboard
Authors: Omar Mohd Amal Asrol , Wisnoe Wirachman , Bakri Azman
Published: September 2013

A fume cupboard is equipment used to carry out chemical reaction process in its working chamber. A suction fan takes air or gas from the working chamber and releases it outside. When the air or gas is flowing from the inlet to the outlet, some recirculation zones may be formed depending on the internal shape design of the fume cupboard. This recirculation zone may create back flow that can be the cause of leakage. Leakage happens when airborne contaminants escape through inlet of the fume cupboard to the user breathing zone and the surrounding air in the room. To have a good fume cupboard, the recirculation zone needs to be minimised. In this paper, the flow characteristic of a Servco fume cupboard will be presented as a result of computational fluid dynamics (CFD) simulation using κ-ω turbulence model. The results are presented in terms of velocity components at different cross sections of the fume cupboard.
Mean Wind Flow Field around Idealized Block Arrays with Various Aspect Ratios
Authors: Abd Razak Azli , Hagishima Aya , Ikegaya Naoki , Mohamad Mohd Faizal , Zaki Sheikh Ahmad
Published: September 2013

This study investigates the characteristic of spatially averaged mean velocity profile and the flow pattern within urban canopy layer especially in pedestrian level using CFD technique. Large eddies simulation (LES) was used to perform a series of simulation of the flow around block arrays with staggered arrangement under various conditions of aspect ratio, αp (roof-to-frontal area ratio) from 0.33 to 3.0. The spatially-average profiles of both mean wind speed and streamwise velocity over various block arrays were compared with each other. The analysis clarified the following two facts. 1) The vertical mean flow structure inside the canyon change due to change a plan area ratio and block aspect ratio. 2) The horizontal mean flow structure around the block change if pedestrian level change form z = 0.05h to z = 0.25h. This can be translated to the effect of high-rise building to the flow around the building.
Stack Cooling Profile of an Air-Cooled 3-Cell Polymer Electrolyte Membrane Fuel Cell Stack
Authors: Wan Mohamed Wan Ahmad Najmi , Atan R.
Published: September 2013

A locally designed, 3-cell closed cathode PEM fuel cell stack was developed as a platform for thermal engineering studies. Stack polarization behavior is combined with thermal behavior analysis to identify the cooling profiles of an air-cooled fuel cell stack under variable load and cooling settings. The objective of the study is to identify the bulk thermal effects of the stack under cooling for further consideration in fuel cell system control development. The stack is designed with 40 cooling channels and tests were conducted with airflows in the range between 200 and 400 Reynolds number. Different fan settings are applied to analyze the response of the design to negative and positive pressure airflows. The temperature measurements are translated into an averaged stack temperature and a subsequent second order thermal analysis showed that an exponential cooling trend is obtained. Analytical evaluation on the dynamic cooling rates relative to response time and cooling trend is also performed and reported.
Operating Condition Optimization of PEMFC via Visualization Technique
Authors: Sainan Khairul Imran , Wan Mohamed Wan Ahmad Najmi , Mohamad Firdaus , Jenal Norhisyam
Published: September 2013

Fuel cell water management has two conflicting requirements; too less water causing membrane dehydration and too much water causing liquid water flooding. Both phenomena resulting in significantly instability voltage performance because of imbalance water presence. Therefore, it is vital to analyze and understand the root cause of the problem hence a 96cm2 transparent fuel cell was analyzed experimentally. The fuel cell allows clear visualization of flow channels, thus making it practical to analyze the transportation of reactants and products behavior. The experimental analyses were conducted under different reactant flow rate and inlet humidification variations. Highest cell performance was obtained under both reactant inlets humidification with largest air flow rates. On the other hand, when fuel and air in dry conditions, relatively lower cell voltage was obtained. Meanwhile, stable voltage was obtained under anode humidified and cathode non-humidified conditions with correct air to fuel ratio. Images of liquid water and voltage behavior are presented graphically corresponding to the changes in performance.
Experimental Investigation of Power Generation from Salinity Gradient Solar Pond Using Thermoelectric Generators for Renewable Energy Application
Authors: Singh Baljit , Varthani Jaisatia , Remeli Muhammed Fairuz , Tan Lippong , Date Abhijit , Akbarzadeh Aliakbar
Published: September 2013

Low grade heat (<100°C) is currently converted into electricity by organic rankine cycle (ORC) engines. ORC engines require certain threshold to operate as the organic fluid generally boils at more than 50°C, and fails to operate at lower temperature. Thermoelectric generators (TEGs) can operate at very low temperature differences and can be good candidate to replace ORC for power generation at low temperatures. In this paper, the potential of power generation from TEG and salinity-gradient solar pond (SGSP) was investigated. SGSP is capable of storing heat at temperature up to 80°C. The temperature difference between the upper convective zone (UCZ) and lower convective zone (LCZ) of a SGSP can be in the range of 40°C 60°C. This temperature difference can be used to power thermoelectric generators (TEG) for electricity production. This paper present result of a TEG system designed to be powered by the hot and cold water from the SGSP. The system is capable of producing electricity even on cloudy days or at night as the SGSP acts as a thermal storage system. The results obtained have indicated significant prospects of such system to generate power from a low grade heat for remote area power supply.
A Sensitivity Study of some Parameters on the Efficiency of a Passive Ventilation System Based on Solar Chimney
Authors: Hamdad Hichem , Larbi Salah , Kessouri Abdelkader
Published: September 2013

The purpose of this work is related to passive ventilation system analysis based on solar chimney. It consists in the determination of the temperature distributions of the wall, the glazing, and along the airflow in the chimney. The air mass flow rate and the instantaneous efficiency of the solar chimney were also determined. The energy performance of the solar chimney has been studied versus some geometrical and environmental parameters. The sensitivity study of the influence of some parameters on the efficiency of the system is also analysed. It is shown that the incident solar radiation has an important role on the energy performance of the solar chimney. Obtained results are compared to those of the literature. Good agreement is observed between the different results.
Study on Indoor Air Quality of a Small Office in a Tropical Country
Authors: Majid Suhana Ab. , Azmarini Ahmad Nazri , Sulaiman Shaharin Anwar
Published: September 2013

Recently, the importance of appropriate Indoor Air Quality (IAQ) attracts interests in health research area. The study of IAQ is important in office. Long term period exposure to poor IAQ level, can lead to discomfort and uneasy feeling and thus may affect productivity and quality of life. The objective of this work is to study the IAQ level in a small lecturer office of an educational building in Malaysia. Throughout this research, the IAQ of a selected lecturer office room was studied. The study involved measurements of indoor air temperature, relative humidity, and CO2 level. From the study, it was found that the level of CO2 temperature and humidity were always within the range of recommended by ASHRAE.
Effects of Different Granular Viscosity Models on the Bubbling Fluidized Bed - A Numerical Approach
Authors: Hilmee M.I. , Chandra Mohan Sinnathambi , Karuppanan Saravanan , Fadhil M. , Lias Mohd Rizal
Published: September 2013

Kinetic Theory of Granular Flow (KTGF) has been successfully incorporated and widely implemented in the Eulerian simulation models in many multiphase cases. The KTGF theory involves many parameters and is applied in the multiphase simulation for the purpose of hydrodynamic properties modeling of the granular phase. This paper is focused on granular viscosity which is a parameter in the KTGF that incorporates three different viscosities arising from the inter-phase and intra phases interaction in a bubbling fluidized bed (BFB). The 2D BFB model of 0.2 m width and 0.8 m length having a 13-hole orifice plate has been modeled for this purpose. The model was constructed using Gambit software version 2.4.6 and then simulated using ANSYS Fluent version 14. Two models of granular viscosity, namely Syamlal-Obrien model and Gidaspow model, were compared based on its effect to the pressure drop and bed expansion of the BFB. The results depicted that the simulation based on Syamlal-Obrien model tends to produce larger bubbles and contributing to a higher pressure drop across the distributor plate as compared to the Gidaspow model.
Fill Removal in Wellbore Using Coiled Tubing
Authors: Yong Lawrence H.P. , Pao William K.S. , Hashim Fakhruldin M.
Published: September 2013

Coiled Tubing (CT) services are widely applied in oil field to remove fill from wellbore. Its function is to restore the productivity of oil and gas well since fill such as sand will regularly block the production line especially at the well bottom. Predicting the behaviors of cleaning fluid and particle transports during the CT cleanout is a major challenge because there are many variables which affect the cleaning operation resulting in loss of cleaning efficiency, waste of cleaning fluid and increase in cost of well services. The objective of this study is to perform detailed analyses of both flow pattern of cleaning fluids and particle transports in wellbore during cleaning process at different cleaning operating conditions and well geometries. In order to achieve the objective, the problem is broken down into two parts; namely the well string and the well bottom/annulus. The well string, which is the coiled tubing itself, is first solved semi-analytically to obtain the exit velocity of the flow nozzle and the accompanying surface pump operating conditions. Once the exit velocity in the coil tubing is known, the value is used as an inlet velocity boundary condition for the bottomhole and the well annulus for the subsequent CFD analysis. Simulating the cleaning process along the entire well span is impractical due to limitation in computational resources. Hence, only a limited section in the bottomhole and annulus were considered, where the calculated transport properties there is sufficient to inform the likelihood of fill being circulated to the surface. The present study identified that diameter ratio of CT and annulus, properties of the cleaning fluid, design of downhole nozzle are the three most important factors influencing the cleanout. The result of this study is a linearized CT parameters design chart that allows user to plan for cleaning operation.
Application of Total Variation Diminishing for 1D Nozzle Problem
Authors: Yusop Fatimah , Basuno Bambang , Omar Zamri
Published: September 2013

Computational fluid dynamics (CFD) is very widespread use every day as a tool in fluid flow analyses. In order to solve the Partial Differential Equation (PDE), there are few approach been introduced. The total variation diminishing (TVD) is a most popular scheme which is usually used in combination with other scheme. Therefore, this study develops CFD code by using Runge-Kutta which based on combination of central scheme and TVD scheme. Comparison was done through purely Runge-Kutta and after implemented TVD. The result shows that combination of Runge-Kutta and TVD approach are more stable as compared to purely Runge-Kutta approach.
A Modified Micro-Scale Abrasion for Large Hard Phase Cermet
Authors: Zakiah Kamdi , Shipway P.H. , Voisey K.T.
Published: September 2013

Various research programmes have been conducted examining cermet coatings in relation to wear, corrosion and the combination of both (erosion-corrosion and abrasion-corrosion). Several methods have been employed to deposit cermet coatings, the most common being thermal spraying or hard facing (weld overlaying).The cermet coatings are carbide-sized ranging from 50 150 μm which is larger than abrasive particles which range between 2 to 10 μm. This allows the abrasive particles to interact with the carbide and matrix separately. Understanding the mechanism of this situation is necessary as abrasion maybe caused by a small abrasive. However, carbide sinking caused by this large carbide leads to diverse local carbide distributions and wear rates with a larger standard deviation. Modified micro-scale abrasion tests were performed with a silica abrasive of 2-10 μm particle size distribution and suspended in water. Due to the sinking of carbide particles during the coating process, the ground samples with more carbide on the surface displayed better wear resistance than those with a lower local carbide content. By using a modified micro-scale abrasion wear test, the correlation between local carbide content and wear rate may be determined with a smaller standard deviation. Rolling wear mode was observed due to the lower degree of hardness of the abrasive compared to the hard phase. The wear behaviour is related to the microstructure.
Thermo Oxidative Degradation Behavior of Jatropha Curcass L. Oil in the Presence of Antioxidant
Authors: Lubis Abdul Munir Hidayat Syah , Ari-Wahjoedi Bambang , Sudin Mustafar , Setyamartana Parman
Published: September 2013

Seed oils were used as base oil since long time ago. However their usage is limited due to its thermo oxidative and cold flow properties. Chemical modification and addition of proper additives are known to be able to improve these limitations. In this work, the effect of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate as potential hindered phenol antioxidant (HPAO) on thermo-oxidative degradation of jatropha oil was investigated. 1, 3, 5 wt% of antioxidant was dissolved into jatropha oil and their thermo-oxidative behavior was studied by using thermo-gravimetric analysis method under oxidative environment. The addition of the HPAO was found to accelerate the occurrence of thermal degradation first onset of jatropha oil. This factor corresponds to reaction of the compound during heating that reduces the peroxides formation to a less-reactive alcohol which is more volatile, thus making the first onset temperature occurred at a lower temperature.
Implementation of Continuous Flow System in Manufacturing Operation
Authors: Naufal Ahmad Adnan , Jaffar Ahmed , Noriah Yusoff , Halim Nurul Hayati Abdul
Published: September 2013

The Continuous Flow System (CFS) is a production system that focuses on one piece flow product at every process in the assembly line. The implementation of this CFS could lead to operational excellence in terms of productivity, space utilization and the number of workers. CFS can be considered as a lean manufacturing foundation and its effective implementation promises significant savings in operation. CFS is achieved through a series of associated kaizen activities at the identified working place. The kaizen activities include establishment of Standardized Work (SW), implementation of U-shaped line and establishment of Material Handling System (MHS). All these activities are carried with one ultimate goal; to eliminate identified waste at the work place. This is essential to any CFS implementation. This paper presents a series of kaizen activities that have been engaged in creating the continuous flow system at the identified assembly line. This is a case-based study which was conducted at a local auto-component company in Malaysia. Findings from the results show that the company has achieved high productivity, minimal space utilization as well as reduction in number of direct manpower. The outcome of this CFS implementation confirms that it has met the supposedly lean principles also known as the one piece flow. Therefore, the objective of this study is to highlight the implemented kaizen activities and its benefit in achieving the CFS of the case study.
Slurry Wear Test of Long Kenaf Polyester Composite (LKPC) and Long Kenaf Polyester with Fiberglass Composite
Authors: Ghani Muhd Azimin Ab , Kamal A.F. Ahmad , Ahmad Mohamad Ali , Taib Y.M.D. , Salleh Z. , Alias S.K.
Published: September 2013

This paper presents an experimental study on the influence of fiberglass woven in Long Kenaf Polyester Composite (LKPC). Wear and friction characteristics were examined using sea water and sand as a slurry. Wear test were carried out using Slurry Erosion Test Rig (TR-40). These tests were performed at room temperature with speed of 200 rpm for every 2 km interval. The results from the tests show that mass loss were depends on the matrix composition of the composite. Surface Roughness, Ra, was consistently reduced after each test in all cases.
Analysis of Transmission Fluid in Manual Diesel Engine by Ferrographic Technique
Authors: Abdul Rahman Norhanifah , Kasolang Salmiah , Ahmad Mohamad Ali , Bakar Mimi Azlina Abu
Published: September 2013

Condition monitoring techniques have been developed in the past two decades in order to predict and overcome the wear related damage progression in gear transmission systems. Ferrographic Technique (FT) is a microscopic analysis to identify the presence of material composition by characterizing particles concentration, type, size, distribution, and morphology. This technique is part of a Predictive Maintenance (PdM) program to avoid a major failure in machine systems. In the present study, analysis of wear characterization in diesel engine by Ferrographic Technique was conducted. Transmission fluid samples were collected from intercity bus and analyzed using Ferrogram Maker (FM-III). Optical microscopy and Predict Chart were used to characterize and identify sample in where groups. It was observed that the corrosive and black oxide wear type were major findings in all samples tested.
Application of Response Surface Methodology to Predict Oil-Film Friction in Journal Bearing
Authors: Ahmed Diyar I. , Kasolang Salmiah , Khidhir Basim A. , Abdullah Nik Rosli
Published: September 2013

Oil-film friction response is one of the key parameters that describe the operating conditions in hydrodynamic lubrication regimes. In the present paper, response surface methodology (RSM) with Box-Behnken experiment Design technique (BBD) has been utilized to predict and evaluate the effects of the three-level-three-independent variables on the oil-film friction. The design independent variables including rotational speed, load and oil-feed pressure were used to develop an empirical model for the oil-film friction in hydrodynamic plain journal bearing. A salient feature of this study is to investigate the interaction between the main three factors and provide a profound understanding on the significance of each factor. The analysis of variance (ANOVA) of the regression model and comparison of predicted and observed response values have showed good correspondence, implying that empirical model derived from response surface approach can predict the response adequately.
Study of Creep Strength for P91 Steels after Short Term Overheating above Ac3 Temperature
Authors: Guat Peng Ng , Ahmad Badrol , Muhamad Mohd Razali , Ahadlin M.
Published: September 2013

Advanced ferritic steels containing 9 wt% Cr are widely used in the construction of supercritical and ultra supercritical boiler components. The microstructure of the as supplied 91 materials consists of a tempered martensite matrix, a fine dispersion of intergranular chromium rich M23C6 precipitates and intragranular carbonitrides MX particles rich in V and Nb. This steel requires post weld heat treatment (PWHT) to produce a tempered microstructure after welding to develop excellent creep strength for high temperature service. Based on past experience, situations may arise whereby the components are subjected to an accidental overshoot in temperature during PWHT. The short excursion to high temperature beyond Ac3 would have resulted in the formation of deleterious phases, for example, soft α-ferrite which has poor creep strength and hard martensite which has a low toughness. In this study, the degraded specimens with soft α ferrite as a result of cooling transformation from 900°C are proven to have a limited creep rupture life where the creep rupture strength dropped remarkably after 1000 hours. As the peak temperature increased to 950°C and 1000°C, hard and brittle martensite was formed on cooling. The creep specimens were found to exhibit better creep strength; most probably the creep behavior was improved by the tempering effect at 600°C during creep tests. Nevertheless, despite the tempering which might have improved the toughness slightly, the high temperature creep rupture stress still had dropped approximately 40%, as compared to the virgin alloys in the range of rupture time from 1,000 hours to 10,000 hours.
A Study on IAQ in a Welding Laboratory
Authors: Azmarini Ahmad Nazri , Majid Suhana Ab. , Zakaria Supa’at Hj , Sulaiman Shaharin Anwar
Published: September 2013

ndoor Air Quality (IAQ) has become an important occupational health and safety concern in educational environment at institutions of higher learning. In a survey conducted on a polytechnic in Malaysia, many of the students and lecturers expressed feeling of discomfort and uneasy due to resulting smoke from the welding activities while attending the workshop session. They felt that the room temperature and humidity also contributed to discomfort. Consequently, students had difficulties to concentrate and focus on their learning. The objective of this study was to determine the indoor air quality of a selected welding laboratory in the polytechnic comprising arc and gas welding stations. The important IAQ parameters considered in this study were the dry bulb air temperature, relative humidity, CO2 level and dust particles. Measurements were conducted using commercial IAQ instruments. From the study it was found that the levels of dust particles was higher than the recommended limit at times in the arc welding station. The CO2 level was observed acceptable in both welding stations. On relative humidity, a mixed result was found. Overall, the results implied that the welding laboratory require attention in meeting acceptable Indoor Air Quality.
Camera Calibration Technique Improvement for 3D Optical Gait Analyzer System
Authors: Ferryanto Fulgentius , Mihradi Sandro , Dirgantara Tatacipta , Mahyuddin Andi Isra
Published: September 2013

In the present work, improvement in camera calibration technique to increase the accuracy of 3D optical gait analyzer system is presented. The improvement was based on correction and modification of the work that has been reported by Zhengyou Zhang. Lens distortions: radial, decentering, and thin-prism distortion were also considered into camera calibration process to minimize the systems error. In the calibration, the projection matrix of Zhangs model was corrected. In addition to that, non-linear constraint in lens distortion calculation was also avoided in order to make the calculation process more efficient. To evaluate the accuracy and efficiency of the proposed method, comparison between present calibration techniques with other camera calibration techniques is conducted. The results show that the proposed technique gives the most accurate result and most efficient calculation process compared to the Direct Linear Transformation (DLT) and Modified Direct Linear Transformation (MDLT) techniques. By using the proposed technique, the root mean square error of the results, if all the lens distortions are considered in calculation, is 0.627 cm with the processing time of 0.1152 s.
Influence of Acoustical Absorbing Material on the Obstacle Detection Angle of an Ultrasonic Sensor
Authors: Kamarulbaharin Z.A. , Rahmat N.
Published: September 2013

Navigation aid is important for the visually impaired person to travel safely. A white cane is normally used to detect obstacles in the persons path but it is limited in its detecting ability as it can only detect obstacles around the length of the cane and is unable to detect moving or overhanging objects. Many types of navigational aids are being developed using ultrasonic sensors to assist the visually impaired to detect obstacles and they are known as Electronic Travel Aids. This paper is focused on studying the influence of acoustical absorbing material on the obstacle detection angle of an ultrasonic sensor. Results showed that a tube lined with acoustical absorbing material attached to the sensor is able to narrow the detection angle for more precise obstacle detection.
New Mouth Spacer Design for Dental Application
Authors: Othman Nurnida Elmira , Abdullah Shahrul Azam , Wahab Hazmyr Abd , Rashid Helmi
Published: September 2013

Mouth spacer is designed to keep the mouth open wide enough for the dentist during dental procedures. Designing and developing a mouth spacer that able to open mouth wide enough and limit the tongue movement is the main objectives for this paper. The new mouth spacer design is expected to reduce gums and jaws pain. This paper incorporates problem identification, idea generation and conceptualization stage in order to generate two design concepts for new mouth spacer designed. The mouth spacer conceptual design with dual function that complied with these project objectives was selected. This design was modeled by using of CATIA software and the suggested material is polyvinylacetate polyethylene (EVA) copolymer and application of silicone sponge gel on the side for patient comfort and satisfaction. The mock up design was prepared using RP machine to visualize the conceptual design. Above all, this paper gives detailed description function of the mouth spacer that may improve the dental surgery application towards a better procedure.
Emulation of Spasticity Symptoms in Upper Limb Part-Task Trainer for Physiotherapist Education
Authors: Zakaria Noor Ayuni Che , Komeda Takashi , Low Cheng Yee , Inoue Kaoru , Raczak Stephan
Published: September 2013

The aim of this study is to develop an adequate part-task trainer occupied with varying levels of severity in spasticity symptoms focusing on the upper limb disorder for occupational therapists. Using the developed part-task trainer, the occupational therapists will have opportunities to repetitively engage in training without patient involvement. The part-task trainer is developed following the structure of human arm articulations with the ability to reproduce the spasticity stiffness. The structured interface programming is built providing three levels of spasticity: mild, moderate and severe. The programming was based on the clinical assessment of spasticity, measuring elbow joint angles and forces exerted by the patients. The recreated spasticity stiffness was evaluated by experienced occupational therapists. Therapists provided positive feedback regarding the mild and moderate level of spasticity leaving further improvement needed in order to reproduce the spasticity at the severe level.
Using URANS to Predict Turbulent Flow Features in a Channel with Lateral Slot
Authors: de Melo Tiago , Goulart Jhon , Souza Sandi
Published: September 2013

Employing a commercial code an unsteady Reynolds Average Navier-Stokes (URANS) with Spalart-Allmaras as turbulence model numerical calculations were performed in order to predict the mean and velocity fluctuations fields in a rectangular channel with a lateral slot. The slot is attached to a lateral wall channel, being characterized by its deepness p and the gap width d. Simulations were performed keeping constant the slot deepness p and the length L while the gap width d was increased from 2 up to 6 mm. Three test sections involving p/d ratios12.50, 6.25 and 4.17were studied. Main results revealed that turbulence production increases with gap dimension decreasing. Large scale structures appearance were also the target of this paper. The study showed gap width plays an important role on this issue. As the gap width was increased large scales structures could be observed farther from channels entrance. Moreover, a kind of viscous effect in the gap was observed. As gap become very tight the frequency of coherent motions is reduced.
Analysis of the Stress and Strain Field of a Thin-Walled Pipeline with Penetrated Crack Using Numerical Simulation
Authors: Cao Yu Guang , Zhao Shuai , Zhang Shi Hua , Han Wei
Published: September 2013

The model of a thin-walled pipeline with penetration crack was built using the software of ANSYS; the model was meshed with shell elements and the singular point was set. As per the results of stress analysis, using the general post processor of ANSYS, the stress intensity factor was calculated based on the plane displacement extrapolation method and the result was compared with that calculated according to the theoretical formula. The characteristic dimension of the crack-tip plastic zone was calculated according to the numerical simulation and theoretical formula respectively. Results showed that the method for building the thin-walled pipeline model with penetration crack and analysis provided in this paper could accurately describe the crack-tip stress and strain field and thus widely be used for the failure analysis of pressure pipelines.
A Numerical Study of the Turbulent Flow over a Cylinder close to Moving Plane
Authors: Gonçalves Noleto Luciano , Goulart Jhon Nero Vaz , Barcelos Júnior Manuel Nascimento Dias , Brasil Junior Antonio C.P.
Published: September 2013

Two-dimensional numerical simulations are performed to analyze the turbulent flow over a circular cylinder close to a moving plane. This flow receives interference from the plane boundary layer, being this effect identified by recirculation zones close to the wall and slight difference in pressure distribution around cylinder. URANS equations and SST modeling are employed to calculate velocity and pressure field. The simulation was performed by a finite element projection scheme. Four distances between the cylinder and the plane are analyzed by the SST model. The SST results showed the generation and development of vortex shedding. Lift and drag coefficients show the flow oscillatory pattern. All results are similar with other numerical results at the literature.
Identification of Parameter Matrices Using Residual Force Vector
Authors: Eun Hee Chang , Kim Rae Jung , Ahn Young Jun
Published: September 2013

The physical parameters obtained from modal tests do not satisfy the eigenvalue function due to modeling and measurement errors, and unexpected damage. The desired dynamic response can be obtained by identifying the most appropriate changes required to obtain the desired dynamic behaviour. The purpose of this study is to present the analytical equations on the updated stiffness and mass matrices in the satisfaction of eigenfunction including residual force vector term. Minimizing the cost functions of the difference between analytical and desired physical parameter matrices, the variations in parameter matrices are straightforwardly derived without using any multipliers. The validity of the proposed methods is evaluated in an application.
Improvement Technology and Research Contents of Machining Accuracy for CNC Machine Tools
Authors: Li Xiao Peng , Yang Hao Tian , Liang Ya Min , Zhao Guang Hui , Ju Xing
Published: September 2013

To bring a new technological revolution, CNC technology and machines give the birth of a new era of control and production. The rapid development of CNC has considerably advanced the precision and ultra-precision machining technology to improve a new level and great attention. From error prevention and compensation, researches of the CNC machines precision at home and abroad were introduced. Key reasons for error compensation hardly use in the domestic widely were pointed out. Finally, the necessity and main contents of error compensation technology were presented according to the actual situation of enterprises.
Development of Mathematical Model for Chip Serration Frequency in Turning of Stainless Steel with Magnetic Damping from Tool Side
Authors: Nurul Amin A.K.M. , Arif Muammer Din , Ahamad Mohrodi Muhd Amir Hafiz B. , Jaafar Israd H.
Published: September 2013

Chatter, the self-excited and violent oscillatory motion between the tool and the work-piece, is detrimental to all machining operations, especially turning. It can lead to poor surface topography, reduced productivity, excessive tool wear, and damaged machine-tool components. Several theories have been introduced to explain chatter, but their predictions have not always been reliable. Therefore, chatter avoidance has relied on inefficient techniques like limiting material removal rates or expensive setups such as actuators and ultrasonic vibration damping systems. However, a deeper investigation into chatter formation reveals that chip morphology and segmentation play a significant role during incidence of machining chatter. The novel Resonance theory of chatter combines the concept of mode coupling of the machining setup and serrated chip formation, to explain the incidence of chatter. To validate the postulates of this theory, models for chip serration frequency are essential. At the same time, a reliable and economical chatter control method is required. To this end, the current research work developed an empirical mathematical model of chip serration frequency in turning of stainless steel AISI 304 using Response Surface Methodology (RSM). Also, it investigated the influence of damping provided by magnetic field from a permanent magnet. The developed chip serration model shows good agreement with experimental data.
On-Machine Measurement of Tooth Profile Errors of Spiral Bevel Gears and its Simulation
Authors: Wang Zhi Yong , Zhai Hua Ming , Chen Hui
Published: September 2013

Precise measurement of tooth profile errors is the key technology for realizing close-loop manufacturing of spiral bevel gears. The measuring principle of tooth profile errors and the processing method of measuring datum is the key technology for realizing precise measuring. Based on the generating principle of spiral bevel gears and the model of CNC machine tool, the on-machine measuring principle and the measuring datum processing method were established. In order to verify the correctness of on-machine measuring principle, the on-machine measuring simulation system was established based on AutoCAD development platform. According to the spatial coordinates and normal vector of the discrete points of theoretical tooth profile, the on-machine measurement of tooth profile errors was simulated by intersection Boolean operation and the values of errors were calculated. The correctness of simulation algorithm is validated by comparing simulation result with the practical measuring result.
Hydrogen Production from Coke Oven Gas by CO2 Reforming over Mesoporous La2O3-ZrO2 Supported Ni Catalyst
Authors: Tao Wei , Cheng Hong Wei , Zhu Qiu Hua , Lu Xiong Gang , Ding Wei Zhong
Published: September 2013

The CO2 reforming of coke oven gas (COG) for hydrogen production was investigated over mesoporous NiO/La2O3-ZrO2 catalysts. At optimized reaction conditions, the conversions of CH4 and CO2 more than 93%, while a H2 selectivity of 94.7% and a CO selectivity of 98.6% have been achieved at 800 °C. The effect of reaction temperature on the catalytic performance was investigated in detail. The catalysts with appropriate La2O3 content showed better catalytic activity and resistance to coking, which will be promising catalysts in the catalytic dry reforming of COG.
Test Point Switch in Low Voltage Electrical Transient Performances Detection Technical Improvement Methods
Authors: Du Xiang Yang , Jia Cong , Xu Chao
Published: September 2013

This article introduces, in low voltage circuit breaker on the switch instantaneous performance detecting station, in order to adapt to the requirement of modern high-speed automated production test, the main factors affecting the detection speed - switch measurement point method is studied, the improvement, the existing method of "contact switch" to replace "non-contact switch method, through theoretical derivation and experimental proof, proved that the new method is feasible and economical.
Design of Dual-Power Supply Automatic Switching Device without Disturbance
Authors: Du Zhi Qiang , Zhang Xiao Fei , Ma Tong Fang , Feng Li Juan
Published: September 2013

The dual power supply system is widely used in our daily life. When power instantaneously switched between the main power and the stand-by power supply, the voltage fluctuations had the varying degree influence on machines. Based on the principle of correlation coefficient of two waveforms and instantaneous reactive power theory, the dual-power supply automatic and instantaneous switching device without disturbance is provided in this paper. The equipment could identify and isolate the broken-down power source in 5ms. At the same time, power supply keeps continuous meeting the requirements of power quality without voltage drop.
On the Spending Structure and Potential of Living Energy: Evidence from a Chinese Rural Village
Authors: Xie Xing Long
Published: September 2013

West China is a typical model of less developed economy, where peasantries depend on fuel woods and straws as one of major living energy resources but energy utilization whereof is low-efficient, triggering a severe squandering. Particularly, at its loess hill areas, a scarcity of living energy resources has relentlessly gripped ecological environment improvement. The study is conducted to estimate the potential and real consumptions in connection with living energy resources for a rural community and further investigating the structure thereof. The results register that an annual average of energy use is 489.5 kgs in standard coal per capita and 2.1 tons in standard coal per 4.2 population household. The study also finds that self-sufficient sources of energy account for 55.0% and developing the use of commercial energy plays a positive role in the transforming of energy composition but adds to economic expenditures on each farming family. A startling discovery is that half of living energy arises from biomass, with coal being in a substantial share, having a negative effect on local ecology. Moreover, those energy resources for cooking and heating purposes, maintaining the basic demand of survival, are highly proportional. Thus, the sampling village is both at a low level in energy utilization and of unsound in its structure. Furthermore, the study finds an alarming waste of power resources, relative to their huge potentials. The study suggests that the village should develop noveltyped energy resources and promote the transformation of its mix for preserving local ecology and building it into a well-being community. Particularly, from the systematology, the study recommends a typical energy engineering of methane production, termed the four-dimension-inone-geometry model, to rural households. These strategies can be applicable to energy engineering construction for other rustic regions.
Application of Differential Evolution Algorithm in Transmission Expansion Planning
Authors: Al Hamrouni Ibrahim , Khairuddin Azhar , Salem M.
Published: September 2013

Transmission expansion planning has become a complicated procedure more than it was. The rapid growth of the transmission networks and the deregulation has introduced more objectives and uncertainties to the transmission network planners. As a result of that, new approach and criteria that can replace the old ones are needed for TEP problem. The main goal of this process is to locate the additional transmission lines that must be added to meet the forecasted load in the system adequately with minimum cost. There have been several methods applied for this purpose; mathematical optimization methods, heuristic and Meta heuristic methods. This paper reviews the use of Meta heuristic method by the means of differential evolution algorithm (DEA) to solve this multi objective optimization problem. In addition, some suggestions have been made by the author that can make the DEA more efficient and applicable in the real world networks.
Structure Force Analysis of Kongzou River Trench-Buried Inverted Siphon
Authors: Tan Min
Published: September 2013

nverted siphon structure is a common water conveyance buildings, computer as a efficient computational tool is used, this paper adopts finite element method to carry out three-dimensional finite element simulation analysis for Kongzou river trench-buried inverted siphon structure. Deducing variation law of the inverted siphons stress and displacement in construction process and operational process. Analysis results further verified that design scheme is reasonable and safe, it has certain reference value.
Simulation Analysis Reinforced Concrete U-Shaped Aqueduct
Authors: Tan Min
Published: September 2013

This paper adopts finite element method to carry out simulation analysis for Enzitan reinforced concrete U-shaped aqueduct. Deducing variation law of the aqueducts stress and displacement in construction process and operational process, researching the rationality of aqueduct structure design scheme. Analysis results show that, Enzitan reinforced concrete aqueduct structure is reasonable, force of aqueduct structure is explicit, it meets the requirements for design.
Study on the Roadway Deformation Based on the Grey Prediction Theory
Authors: Luo Fang Liang , An Li Qian , Chen Xiang Hai , Mao Ling Tao
Published: September 2013

Applying grey theory into the monitoring prediction of surrounding strata deformation in underground roadway either can overcome the problems that various uncertain factors affect the prediction of strata deformation rule, or can provide the theory base for rational roadway supporting.
Structural Behaviors of Advanced Truss Platform for Effective Road Tunnel Maintenance
Authors: Lee Dong Kyu , Lee Jae Hong , Kim Doh Wan , Shin Soomi , Park Hyun Jung
Published: September 2013

This study shows structural behaviors of an innovative space truss typed temporary structure which is effectively used to maintenance and repairs of road tunnels. This evaluated structure has merits to carry out maintenance works of tunnels without blocking cars and transportations. Numerical modeling and analytical testing of the space truss system are investigated by using a commercial engineering program, i.e., ABAQUS 6.5-1, and then it are verified that the truss system takes both structural safety and effective function for maintenances and repairs of road tunnels.