Formulation of refined, bleached and deodorised palm stearin with zinc dialkyl-dithiophosphate additive and its tribological performance

Vegetable oils have recently received worldwide attention for their use as a lubricant base stock that has numerous advantages, including their environmental friendliness. In this study, a refined, bleached and deodorised palm stearin was selected as the base lubricant, and its friction and wear performance were investigated with a pin-on-disk tribotester. The effect of zinc dialkyl-dithiophosphate (ZDDP) additive in concentrations of 1wt%, 3wt% and 5wt% on friction and wear performance were evaluated. Commercial semi-synthetic oil SAE 15W50 was used for comparison purposes. The experiments were conducted at a sliding speed of 1.5 m/s under a normal force of 9.81 N for 60 min. Results show that an increase in ZDDP concentrations improved both friction reduction and wear performance of the lubricant. The coefficient of friction (COF) of RBD palm stearin was reduced approximately at 71% when 5wt% of ZDDP was added and it shows that the friction reduction performance of PS+5wt% (COF=0.039) was comparable to SAE 15W50 (COF=0.035). While, wear coefficient of RBD palm stearin was reduced significantly from 2.08 × 10−3 to 8.89 × 10−5 when 5wt% ZDDP additive was added and it shows that the wear performance of PS+5wt% was better than that of SAE 15W50, 1.94 × 10−4. Further analysis of the wear worn surface with a high-resolution optical microscope was also conducted with a surface profilometer to examine the metallurgy of the pin surface and the roughness of the pin

Mountain-Shaped Coupler for Ultra Wideband Applications

This paper demonstrates a novel mountain-shaped design for a compact 3-dB coupler operating at ultra-wideband (UWB) frequencies from 3.1GHz to 10.6 GHz. The proposed design was accomplished using multilayer technology in which the structure is formed by three layers of conductors interleaved by a layer of substrate between each conductor layer. Simulation was carried out using CST Microwave Studio; the result was then compared with results from rectangular and star-shaped couplers that implemented the same technique. The results obtained show that the proposed new coupler has better performance compared to both rectangular and star-shaped coupler designs in terms of return loss, isolation, and phase difference. The coupler was fabricated and measured; the measurement results satisfactorily agree with the simulation results

Textile Diamond Dipole and Artificial Magnetic Conductor Performance under Bending, Wetness and Specific Absorption Rate Measurements

Textile diamond dipole and Artificial Magnetic Conductor (AMC) have been proposed and tested under wearable and body centric measurements. The proposed antenna and AMC sheet are entirely made of textiles for both the substrate and conducting parts, thus making it suitable for wearable communications. Directive radiation patterns with high gain are obtained with the proposed AMC sheet, hence minimizing the radiation towards the human body. In this study, wearable and body centric measurements are investigated which include bending, wetness and Specific Absorption Rate (SAR). Bending is found not to give significant effect to the antenna and AMC performance, as opposed to wetness that yields severe performance distortion. However, the original performance is retrieved once the antenna and AMC dried. Moreover, notable SAR reduction is achieved with the introduction of the AMC sheet, which is appropriate to reduce the radiation that penetrates into human flesh

An Electronically Reconfigurable Patch Antenna Design for Polarization Diversity with Fixed Resonant Frequency

In this paper, an electronically polarization reconfigurable circular patch antenna with fixed resonant frequency operating at Wireless Local Area Network (WLAN) frequency band (2.4-2.48 GHz) is presented. The structure of the proposed design consists of a circular patch as a radiating element fed by coaxial probe, cooperated with four equal-length slits etched on the edge along x-axis and y-axis. A total of four switches was used and embedded across the slits at specific locations, thus controlled the length of the slits. By activating and deactivating the switches (ON and OFF) across the slits, the current on the patch is changed, thus modifying the electric field and polarization of the antenna. Consequently, the polarization excited by the proposed antenna can be switched into three types, either linear polarization, left-hand circular polarization or right-hand circular polarization. This paper proposes a simple approach that able to switch the polarizations and excited at the same operating frequency. Simulated and measured results of ideal case (using copper strip switches) and real case (using PIN diode switches) are compared and presented to demonstrate the performance of the antenna

Single channel magnetic induction spectroscopy technique for fetal acidosis detection

Current fetal acidosis diagnosis needs an invasive measurement which required a doctor to puncture fetal scalp to acquire blood pH. This method introduced risk to the fetal which fetal scalp may bruise and infected. This paper discusses a noninvasive method employing a single channel magnetic induction spectroscopy technique as an alternative method to diagnose acidosis in fetal without puncturing the fetal scalp. The studies are based on numerical simulation models to investigate the most feasible sensor coil that is sensitive and effective to be implemented in hardware setup as the shape of coil influences directly the sensing performance of the magnetic induction spectroscopy system. The study has found that the circular coil is more sensitive than linear coil. The system tested with different pH samples to mimic the blood pH value. The result is very promising with good correlation approaching 1 has been achieved. Therefore, magnetic induction spectroscopy technique has good opportunity to be applied as an alternative method to detect acidosis in the fetal with circular coil is performed as the best sensing coils for MIS hardware

A novel green antenna phase-shift system with data acquisition boards

A novel green phase shifter system is proposed in this research. The system is developed by a combination of reconfigurable beam steering antennas and data acquisition (DAQ) boards. A combination of two reconfigurable beam steering antennas, located side-by-side, forms a spatial configuration structure with a fabricated ‘green’ element plank of rice husk placed in between. The concept of a spatial configuration technique has been ‘mutated’ by shifting the structure of spiral feed line and aperture slots of first beam steering antenna by as much as 45 ◦ . The PIN diode switches connected to the DAQ boards enable the intelligent capability of the spatial antennas. The activation of certain degree radiation patterns of either the first beam steering antenna or the second beam steering antenna depends on the memory of the DAQ boards — Beam Manager. When an intruder comes from the cardinal angles of 0◦/ 360◦, 90◦, 180◦, or 270◦, its range and angles’ location will be automatically detected by the first antenna through the output ports of the 1st DAQ: P1.0, P1.1, P1.2, and P1.3. The second antenna is then activated by the output ports of the 2nd DAQ: P2.0 up to P2.3, to adaptively maneuver the beam towards four different ordinal directions of 45◦, 135◦, 225◦, and 315◦

Video monitoring application using wireless sensor node with various external antenna

Surveillance and monitoring has become very important for security reasons these days. The use of wireless sensor node device offers a variety of platform depends on the attached sensor. When an image sensor is attached, the wireless sensor node is capable of monitoring an area wirelessly. Since wireless environment uses antenna to transmit and receive data, antenna is an important component that affects the video monitoring performance. This paper describes a surveillance system using Raspberry Pi with various external antenna. The Raspberry Pi with Pi Camera module and various types of antennas was used for testing and experimentation in line-of-sight (LOS) and non-line-of-sight (NLOS) condition. The results revealed that the Yagi Uda antenna gives the best output in terms of its signal strength and average Receive (Rx) rate

Design and Analysis of Optimum Performance Pacemaker Telemetry Antenna

The demand for health technology is increasing especially in the telemetry applications. These applications generally use implanted antennas to be utilized for data transfer from patients to other reader devices. This procedure can make the health care more efficient since it provides fast diagnosis and treatment to the patient. Therefore, in order to effectively implement an implanted antenna inside the human body, thorough numerical analysis and simulations are required prior to the fabrication of antenna. In this work, an implanted antenna has been proposed to be designed at 402.5MHz within the biomedical frequency band of 402- 405MHz. By introducing a compact loop antenna for telemetry applications in a Pacemaker, a number of advantages can be achieved for health care such as efficient data information and quick diagnosis. Moreover, in this work an investigation of compact loop antenna with casing in Pacemaker has been carried out by placing the antenna inside the phantom of human body model

Automated attendance management and alert system

“Automated Attendance Management and Alert System (AAMAS)” was developed to help UiTM lecturers and Academic Affairs Department in monitoring students’ absenteeism and improving the absenteeism record management. AAMAS provides various functions, from managing and recording students’ attendance record, to sending automatic alerts to students with high absenteeism via short messaging system (SMS) and email. The system is also able to track the number of alerts sent. Through AAMAS, a significant amount of time and money can be saved, for instance time needed to fill out forms and issue notification letters manually can be minimized significantly. Besides, message interception, human resources and human errors can also be reduced. AAMAS which was tailored to UiTM could be also enhanced and custom-made to cater other learning institutions’ requirements throughout Malaysia.Keywords: automated system; attendance management; system development