239 research outputs found
Virtual Collaborative R&D Teams in Malaysia Manufacturing SMEs
This paper presents the results of empirical research conducted during March to September 2009. The study focused on the influence of virtual research and development (R&D) teams within Malaysian manufacturing small and medium sized enterprises (SMEs). The specific objective of the study is better understanding of the application of collaborative technologies in business, to find the effective factors to assist SMEs to remain competitive in the future. The paper stresses to find an answer for a question “Is there any relationship between company size, Internet connection facility and virtuality?”. The survey data shows SMEs are now technologically capable of performing the virtual collaborative team, but the infrastructure usage is less. SMEs now have the necessary technology to begin the implementation process of collaboration tools to reduce research and development (R&D) time, costs and increase productivity. So, the manager of R&D should take the potentials of virtual teams into account
Brain Acceleration During Ball-To-Head Impact in Soccer
There has been a long debate whether purposeful heading could cause harm to the brain. Studies have shown that repetitive heading occasion could lead to degeneration of brain cells, which is similarly found in patients with mild traumatic brain injury. A two-degree of freedom linear mathematical model was developed to study the impact of soccer ball to the brain during ball-to-head impact in soccer. From the model, the acceleration of the brain upon impact can be obtained. The model is a mass-spring-damper system, in which the skull is modelled as a mass and the neck is modelled as a spring-damper system. The brain is a mass with suspension characteristics that are also defined by a spring and a damper. The model was validated by experiment, in which a ball was dropped from different heights onto an instrumented dummy skull. The validation shows that the results obtained from the model are in a good agreement with the brain acceleration measured from the experiment. This findings show that a simple linear mathematical model can be useful in giving a preliminary insight on what human brain endures during a ball-to-head impact
Air Quality Study at Different Elevation Levels Using Drone Payload Air Quality Measurement Device (D-PAQ)
Construction sites can be found in both urban and rural areas, often in close proximity to residences. They can thus cause home pollution due to the distance and the materials used. This study aims to visualize PM2.5, PM10, temperature and humidity by producing air quality mapping and correlating parameters at the stadium and construction site. An Arduino-based air quality measurement payload device was developed to measure the air quality by different levels. The drone was used to collect air quality data by mounting the device to the drone. Measurements were taken at three different elevations for each study area, and the application software generates the air quality map based on the location coordinates. The correlation evaluation of the concentration of PM2.5 and PM10 with temperature and humidity was then determined. The results showed that the concentrations of PM2.5 and PM10 at the construction site are much higher compared to the stadium due to the construction activities nearby.
Keywords: air quality, unmanned aerial vehicle, mappin
Application of genetic algorithm on model-based optimisation of supercritical carbon dioxide extraction: An overview
Green supercritical carbon dioxide extraction technology has gained enormous interest especially in the application of extraction of natural products. The use of carbon dioxide as solvent in the extraction process is very advantageous as carbon dioxide is cheap, non-Toxic, high selectivity, and can easily be separated. Supercritical carbon dioxide extraction is considered as a complex process as more factors affect the outcome of the process as compared to conventional extraction methods. This technology requires higher cost to setup and maintain the equipment. For these reasons, the whole process needs to be fully understood to ensure that the process is well optimised. Mathematical modelling is a way to explain the relationship between process variables and the outcome of the process. The optimisation of supercritical carbon dioxide extraction needs to be highly integrated to be feasible, which means that a complex mathematical model is involved. In overcoming this problem, genetic algorithm was applied in several studies. Genetic algorithm is one of the optimisation methods that is able to optimise a complex and large scale of problems, with high accuracy and practicality. This paper intends to give an overview on the application of genetic algorithm in the optimisation of mathematical modelling of supercritical carbon dioxide extraction process
Simulation of fuel economy for Malaysian urban driving
By understanding the implications of real-world driving conditions, improved fuel economy via a strategy of key technologies can be implemented to assist fuel economy validation during development programs. Vehicles in real-world driving conditions regularly travel at idle, low and medium speeds, particularly for urban driving, and this has a crucial weight in overall vehicle fuel economy, given the residencies at the lower engine speed and load region. This paper presents the validation of the derived engine conditions representing Malaysian actual urban driving in an attempt to formulate representative fuel economy data. The measurements were conducted through on-road urban driving within Kuala Lumpur to establish representative driving conditions. The effectiveness of the proposed conditions was then validated in terms of fuel economy using a simulation. The discrepancy between the fuel economy in the proposed conditions and the real-world measurements has improved, falling to 11.9% compared to 43.1% reported by the NEDC
Manual and Electronic Detection of Subgingival Calculus: Reliability and Accuracy
Calculus consists of mineralised dental biofilm on the surfaces of teeth and dental prosthesis, the location of which can be detected by using a periodontal or an electronic probe. Detection of subgingival calculus is critical for successful treatment outcome in the management of periodontal patients. The aim of this study was to detect subgingival calculus using manual and electronic probe and to compare the reliability and the accuracy of both methods. The study was carried out in vitro on thirty-two extracted teeth with calculus mounted in frasaco model. A total of 192 sites on six surfaces of the teeth bucally and lingually were recorded for the presence of subgingival calculus. Manual probing of calculus depended on tactile sensation and experience; where as electronic probing gave sound and light signal. The results showed that at the depth of 1-3mm, manual probing could detect 62.7% of calculus and electronic probing could detect more at 77.1%. At the deeper sites of 4-6mm, the ability for detection using electronic probing reduced to 14.1% with failure for detection at ≥ 7mm depth. However manual probing recorded more at 25% for 4-6mm calculus and 4.7% at ≥7mm. Manual and electronic probing has different sensitivity in detecting subgingival calculus with electronic probing being more sensitive at shallow sites and failed to detect calculus at deeper sites. It also has difficulty to differentiate between calculus and other roughness on tooth surfaces. These findings highlighted the accuracy and reliability of manual detection for deeper calculus. Redesigning calibration and length of electronic probe can improve its usage. Further study on clinical application to assess the impact of both probing may benefit clinical teaching of subgingival calculus detection and the outcome of periodontal patient’s management
AC breakdown behavior of SF6/N2 gas mixtures under non-uniform field electrode configurations
Sulphur hexafluoride (SF6) gas owns remarkable properties as insulation medium and current interrupter, which make it being widely used in gas-insulated equipment up to now. However, SF6 gas has a drawback that gives adverse effect to the environment since it is a strong greenhouse gas. As the effort to minimize the SF6 usage, this study was conducted to investigate the AC breakdown behavior of SF6/N2 gas mixtures with 10/90 ratio at low pressure levels (i.e. 0.11 MPa to 0.15 MPa) under non uniform field (i.e. R0.5-plane and R6-plane electrodes configurations). The results of the study indicate that the breakdown voltage of SF6/N2 gas mixtures in non-uniform field increases linearly with the increase of gas pressure and electrodes gap distance. As a function of gap distance, a higher increasing rate of breakdown voltage values were achieved at lowest pressure of 0.11 MPa compared to other pressure levels. In addition, it is also found that a higher breakdown voltage values was obtained under R6-plane configuration. But, the difference in breakdown voltage values between R0.5-plane and R6-plane configuration is less significant as the gap distance is increased. It is also observed that the field efficiency factor of R6-plane is higher than R0.5-plane which indicates a more uniform field exists between the electrodes
The effects of physiological biomechanical loading on intradiscal pressure and annulus Stress in lumbar spine: a finite element analysis
The present study was conducted to examine the effects of body weight on intradiscal pressure (IDP) and annulus stress of intervertebral discs at lumbar spine. Three-dimensional finite element model of osseoligamentous lumbar spine was developed subjected to follower load of 500 N, 800 N, and 1200 N which represent the loads for individuals who are normal and overweight with the pure moments at 7.5 Nm in flexion and extension motions. It was observed that the maximum IDP was 1.26 MPa at L1-L2 vertebral segment. However, the highest increment of IDP was found at L4-L5 segment where the IDP was increased to 30% in flexion and it was more severe at extension motion reaching to 80%. Furthermore, the maximum annulus stress also occurred at the L1-L2 segment with 3.9 MPa in extension motion. However, the highest increment was also found at L4-L5 where the annulus stress increased to 17% in extension motion. Based on these results, the increase of physiological loading could be an important factor to the increment of intradiscal pressure and annulus fibrosis stress at all intervertebral discs at the lumbar spine which may lead to early intervertebral disc damage
The effects of spring stiffness on vortex-induced vibration for energy generation
Vortex-induced vibration (VIV) is the turbulent motion induced on bluff body that generates alternating lift forces and results in irregular movement of the body. VIV-powered system seems a good idea in greening the energy sector and most importantly is its ability to take advantages of low current speed of water to generate electricity. This paper aims to investigate the effects of spring stiffness on the characteristic of VIV. The study is important in order to maximize these potentially destructive vibrations into a valuable resource of energy. Five cylinders with the range of 0.25 to 2.00 inch diameter are tested to study the behavior of VIV. Results from this experiment indicates that, the 2.0 inch cylinder gave the lowest error in frequency ratio which is 1.1% and have a high potential of lock-in condition to occur. In term of maximum amplitude, this cylinder gave the highest amplitude of oscillation motion that is equal to 0.0065 m
Simulation Analysis on the Potential Application of Matched Bandstop to Bandpass Filter in Filter Integrated SPDT Switch Design
This paper presents the simulation analysis on the potential application of matched bandstop to bandpass filter in filter integrated switch (FIS) design. The FIS consists of matched band-stop to bandpass filter integrated with single-pole-double-throw (SPDT) switch. The proposed design was demonstrated for 2.45 GHz applications in wireless data communication systems such as Bluetooth and Zigbee. The filter was based on L-shape lossy resonator, which can provide an absorptive feature. PIN diodes were used as switching elements for the SPDT switch and to reconfigure between band-stop and bandpass responses. Therefore, the key advantages of the proposed design are high isolation and good return loss at both ON- and OFF-state ports. As a result, the simulation showed the followings: higher than 10 dB of return loss and greater than 25 dB of isolation at the operation frequency
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