Domestic power situation is changing rapidly, and effective energy-saving measures in offices and homes are required. In office buildings, lighting consumes about 20% of the power consumption, and air-conditioner cons...
详细信息
In this paper, a planar Rotman lens featured as beamforming and multiple beams is presented, aimed at the potential use for 5G communication. The feeding network and the radiating patches are made as a single layer Ta...
详细信息
ISBN:
(纸本)9781467372381
In this paper, a planar Rotman lens featured as beamforming and multiple beams is presented, aimed at the potential use for 5G communication. The feeding network and the radiating patches are made as a single layer Taconic-microstrip structure for a 24-GHz area operation for low cost and practicality. The beamforming characteristics are verified by the full-wave simulation which is validated by the fabrication and measurement.
This work investigates the friction reduction capability of dimple – textured steel surface created using a vertical milling machine. A suitable geometry for creation of dimples was chosen and cashew nut shell liquid...
This work investigates the friction reduction capability of dimple – textured steel surface created using a vertical milling machine. A suitable geometry for creation of dimples was chosen and cashew nut shell liquid (CNSL) was used as lubricant. A L9 orthogonal array was created using Taguchi design of experiment where load, speed of disc and duration of the test were chosen as the parameters. A pin – on – disc tribometer is used to find the coefficient of friction (COF) between an EN 24 steel pin and the dimple – textured steel disc made of low carbon steel. ASTM G99 standard was used for the test and the lubricant was supplied intermittently. Optimization was carried out using Taguchi method, where the optimized condition of the input parameters influenced a substantial change of 32.38% in COF as compared to the non – textured disc surface. The lubricant retention capacity of the dimple was the primary cause for the decrease in COF.
In recent years, a boom in the use of multi-purpose robots has been observed. This has increased the need for developing stable and optimized All-Terrain Robots. These robots have excellent off-roading capabilities th...
In recent years, a boom in the use of multi-purpose robots has been observed. This has increased the need for developing stable and optimized All-Terrain Robots. These robots have excellent off-roading capabilities that can be useful for disaster relief operations, extra-terrestrial applications, commercial mining activities and safe agricultural practices. The designs for All-Terrain Robots proposed in the literature reports that the eccentric loads used for suspension can deteriorate the elasticity of the spring, also these robots are prone to punctures. Moreover, there is a scope to improve the gripping capabilities, and longevity, to extend the applications and stability of these robots. These challenges motivated the authors to develop a novel design of an all-terrain multipurpose robot for maneuvering through rugged terrain. In this design, the authors investigated multiple suspension systems, such as Rocker-Bogie, CRAB and RCL-e and selected the appropriate suspension mechanism for smooth and stable rover traversal. They also focused on choosing the tires for providing the maximum gripping capabilities, longevity, and resistance to punctures. The authors implemented an electronic subsystem to pilot the robot for maneuvering through rough, slippery, and sloppy terrains by optimizing the motor’s torque and rotational speed. They also implemented a hardware-based architecture that includes embedded systems, sensors, circuits, motors, and power distribution for a six-wheeled ATR to visualize safe and efficient connections. Now, the authors evaluated the performance of the proposed robot in terms of vertical drop, stress-strain tests and stability in a simulated environment. Based on the simulation results, they demonstrate the supremacy of the proposed design over the existing designs of robots.
Electro-Hydraulic Servo (EHS) system is a well-known nonlinear system in various types of industries due to its outstanding characteristics over other actuators. Despite its wide applications in industries, this syste...
Electro-Hydraulic Servo (EHS) system is a well-known nonlinear system in various types of industries due to its outstanding characteristics over other actuators. Despite its wide applications in industries, this system also suffering from nonlinearities and parameter uncertainties. Sliding Mode Controller (SMC) has been proven by many researchers to be effective in positioning control of the nonlinear system. However, SMC controller parameters must be tuned in appropriate ways to control the EHS system. In this research, an SMC strategy which combines with an enhanced PSO called Multi-Objective Particle Swarm Optimization (MOPSO) is proposed in positioning control of the EHS system. The conventional PSO is design as well for comparison purpose. The output performance is analysed and verified using different performance indexes such as rise time, settling time, overshoot percentage, and root mean square error. The results show that the MOPSO is better in tuning the controller parameters.
Packaging process had been studied on capacitance accelerometer. The silicon-glass bonding process had been adopted on sensor chip and glass, and sensor chip and glass was adhered on ceramic substrate, the three-layer...
Packaging process had been studied on capacitance accelerometer. The silicon-glass bonding process had been adopted on sensor chip and glass, and sensor chip and glass was adhered on ceramic substrate, the three-layer structure was curved due to the thermal mismatch, the slice error of glass lead to asymmetrical curve of sensor chip. Thus, the sensitive mass of accelerometer deviated along the sensitive direction, which was caused in zero offset drift. It was meaningful to confirm the influence of slice error of glass, the simulation results showed that the zero output drift was 12.3×10-3 m/s2 when the deviation was 40μm.
Recently, several bus accidents happened because of bus driver’s behavior. In fact, there is no dedicated tool for assisting them to drive safely. This project gives solutions to this by assisting the driver, accordi...
Recently, several bus accidents happened because of bus driver’s behavior. In fact, there is no dedicated tool for assisting them to drive safely. This project gives solutions to this by assisting the driver, according to the speed and acceleration of the bus. These data are collected by using a motion processing unit (MPU-6050) and a global positioning system (GPS) and then indicate the driving mode status on the LEDs. All data and status are recorded in a secure digital (SD) card for the authority or the bus company to analyze the driving behavior of a bus driver. This system has been successfully developed and tested in two different areas which includes the UTHM main campus and the road from Parit Raja to Batu Pahat.
The sealing of the high-pressure pump is carried out by means of a seal between the pump drive shaft and the front plate to keep the fuel inside them. The literature presents numerous studies carried out on how these ...
The sealing of the high-pressure pump is carried out by means of a seal between the pump drive shaft and the front plate to keep the fuel inside them. The literature presents numerous studies carried out on how these seals last in time and on their composition. Due to the fact that during assembly or during the mounting of the pump on the engine may occur accidental defects on the sealing area, our interest in this paper is to investigate their impact on pump operation. The damages were explored on a test bench a certain number of kilometres and later analysed their impact on the pump using an ultraviolet chamber in a dark room. The experimental analyses were carried out using the EvoCam optical microscope, but also with the help of computer tomography procedure.
Nowadays, 3D printing (3DP) has become a popular personal approach as it being able to produce a product more quickly and increased accessibility. 3DP was also known as Rapid Prototyping (RP) where it builds three-dim...
Nowadays, 3D printing (3DP) has become a popular personal approach as it being able to produce a product more quickly and increased accessibility. 3DP was also known as Rapid Prototyping (RP) where it builds three-dimensional (3D) products using layer by layer method from a Computer Aided Design (CAD) files. However, dimensional accuracy (DA) was one of the major problems of these technologies. Thus, it is important to evaluate the best parameter in order to find out the best adjustment to avoid the dimensional error. The objectives of this study were to find the best parameter setting and to evaluate the influence of the changing parameter in 3D part shrinkage error. This study only focused on desktop 3D printer machines, which was the Odyssex Designex X2 and the material used was Acrylonitrile Butadiene Stryrene (ABS). In investigate which factors that most significant to shrinkage, DOE approach was used with parameters such as layer thickness (LT), nozzle temperature (NT), print speed (PS), infill density (ID) and bed temperature (BT). Minitab software has been used for analysis purposes. The significant process parameter effect and the best setting of parameter were determined from ANOVA, Main Effect Plot (MEP) and regression method. Finally, from the results of this study, BT was the most significant effect to shrinkage (SK) and the best setting for achieving less value in SK in ABS materials was LT = 0.25mm, NT = 235°C, PS = 55mm/s, ID = 25% and BT = 100°C. The validation runs was conducted based on the best setting value and it shows that the different between predicted value and actual value was 2.56%. This means that the model was reasonably accurate and the best parameter setting was highly recommended. The results also proved the quality of products was improved by using the DOE approach.
Nowadays, most engines which equip agricultural machines, ships and cars are diesel ones with a common-rail high-pressure direct injection system. They are providing the advantages of fuel economy, low emission level,...
Nowadays, most engines which equip agricultural machines, ships and cars are diesel ones with a common-rail high-pressure direct injection system. They are providing the advantages of fuel economy, low emission level, and reduced noise in comparison to conventional direct or indirect injection systems. The heart and the most stressed part of the common-rail system is the high-pressure fuel pump which is driven by the engine camshaft, and its role key is to compress the fuel at pressures over 2000 bar. The high-pressure fuel is delivered from pump to the engine combustion chamber via high rail pipes, high-pressure accumulator (rail) and injectors. Compressing the fuel and sending it towards high-pressure accumulator (rail), in some specific cases the pump generates an audible disturbing noise that gets louder than the engine combustion noise. The paper first offers an overview of our experiments performed on common-rail high-pressure fuel pumps in order to find the noise contributor and to develop measures to reduce the disturbing noise. The experimental investigations have proved that the noise occurs when the fuel is compressed and the outlet valve is opening. Then, our experimental study focuses on outlet valve behaviour from design and noise emissions point of view at idle engine speed.
暂无评论