Sensor material characterisation for magnetometer application

Pengukuran dan gangguan medan magnet arus terus dan arus ulang-alik memerlukan penderia medan magnet yang mempunyai kepekaan yang tinggi dan stabil. Untuk menghasilkan penderia tersebut, ciri-ciri bahan magnet yang baik telah dikenalpasti. Beberapa jenis bahan magnet yang berbeza telah digunakan untuk mengkaji ciri-ciri dan kesannya terhadap medan magnet. Teras gelang yang diperbuat daripada bahan-bahan magnet tersebut direkabentuk dengan dimensi yang sama bagi membolehkan perbandingan dibuat dengan mudah. Selain itu, rod tunggal dan berkembar juga telah digunakan sebagai teras penderia fluxgate, untuk melihat prestasi setiap jenis penderia tersebut. Kedua-dua penderia tersebut telah diuji dengan menggunakan dua sumber bahan magnet iaitu bar magnet tetap dan solenoid dengan diameter dawai yang berbeza. Isyarat keluaran bagi setiap penderia fluxgate seterusnya diproses bagi mengenalpasti hubungannya dengan ketumpatan medan magnet

Bow-Tie Microstrip Antenna Design

In this paper, the bow-tie microstrip antennas have been designed with two different angles of 40° and 80°. An investigaton on the effect of the angle to the return loss and radiation patterns had been carried out. The impedance matching network with the niicrostrip transmission line feeding was used in this study. Simulation and measurement results for the return loss and radiation patterns were presented

A supplier selection strategy within the Malaysian telecommunications industry

The telecommunication industry in Malaysia has grown rapidly over the last 15 years, with effective supply chain management becoming increasing important within the sector. A multitude of providers and part owned Malaysian government companies, vendors and suppliers are involved in generating and creating value-adding products and services within this sector (across wireless, wireline, broadband business and consumer lines of business). This paper describes key challenges facing a major telecoms service provider in Malaysia with regards to drivers involved in the overall procurement and supplier selection with regards to components of performance management, decision-making, selection techniques, quality and cost management, procurement policy and procurement ethics. This paper further focuses on defining and detailing research currently being undertaken to develop a framework for identifying supplier selection drivers that are inherent within the sector and suggests a research approach to investigate and develop strategies for supplier selection for the telecommunications industry in Malaysia

Inter-Code Comparison of Computational VERA Depletion Benchmark Using OpenMC, OpenMC-ONIX and DRAGON

This research focuses on the comparative analysis of the PWR fuel assembly based on VERA depletion benchmark problems using community-developed open source Monte Carlo code OpenMC, python based burnup code system ONIX (a coupling interface for Monte Carlo code OpenMC), and deterministic DRAGON code. The depletion analysis was performed using OpenMC and ONIX with ENDF/B-VII.1 nuclear data library, and DRAGON with SHEM-361 based DRAGLIB format library (ENDF/B-VII.1). The code-to-code analysis on the evolution of , atom number density, and power distribution as a function of burnup has been performed and the result shows a good agreement with the maximum difference within 200 pcm at EOC. However small discrepancy around 90 pcm has been observed in  calculated by DRAGON compared to OpenMC in the presence of integral fuel burnable absorbers (IFBA). The above-mentioned codes have been validated successfully for the first time against PWR fuel assembly based on VERA depletion benchmark problems. It can be concluded that initial implementation of these codes at the Department of Nuclear Science and Engineering under Military Institute of Science and Technology, Dhaka, was successful and that further research works are to be performed to utilize these codes for depletion/neutronics calculation of existing 3MW TRIGA Mark-II research reactor and VVER-type power reactor that is to be commissioned in Bangladesh

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

Foundations on Stone Columns Resting on Coralline Limestone

The subsoil conditions along the Red Sea coast in Saudi Arabia are complex due to existence of very thick beds of coralline limestone of recent geological origin. These coral beds are soft, porous and nonhomogeneous. They are often interspaced with large cavities and soft sandwiched layers of finer particles. Analysis of the subsoil conditions to a fifty meter depth based on data from deep boreholes, Standard Penetration Tests (SPT), Quasi Static Cone Tests (DCT) and large size Plate Load Tests is presented. The strength and compressibility characteristics of the strata and the correlation factors for the SPT and DCT in coralline limestone are evaluated. The results from the plate load tests conducted on natural soil and on soil compacted with stone columns are included. An evaluation of the performance of the foundation for the heavy turbines resting on soil compacted with vibro-compaction replacement method with stone columns was made

Optimization of Pulsed Nd:YAG Laser Melting of Gray Cast Iron At Different Spot Sizes for Enhanced Surface Properties

This paper presents a laser surface modification process of gray cast iron using different laser spot size with an aims to eliminate graphite phase and achieve minimum surface roughness and maximum depth of molten zone and microhardness properties. The laser processing was conducted using JK300HPS Nd:YAG twin lamp laser source pulse TEM 00 mode, 50 W average power, 1064 nm wavelength and different laser spot sizes of 1.0 mm, 1.2 mm, 1.4 mm and 1.7 mm. Three controlled parameter were peak power (Pp), pulse repetition frequency (PRF) and traverse speed (v). Increasing spot size the parameter setting where peak power is increased and pulse repetition frequency and traverse speed is decreased. The modified surface of laser surface melting was characterized for metallographic study, surface roughness and hardness. Metallographic study and surface morphology were conducted using optical microscope while hardness properties were measured using Vickers scale. Surface roughness was measured using a 2D stylus profilometer. From metallographic study, the graphite phase was totally eliminated from the molten zone and formed white zone. This phenomenon affected hardness properties of the modified surface where maximum hardness of 955.8 HV0.1 achieved. Optimization of laser surface modification was conducted for minimum surface roughness and maximum depth of modified layer and hardness properties. From the optimization, the higher desirability is 0.902. The highest depth of molten zone obtain from spot size 1.4 mm at 132 µm and the highest hardness is 989 HV0.1 at laser’s spot size 1.0 mm. The surface roughness increased when the spot size increased from 3.10 µm to 7.31 µm. These finding indicate potential application of enhanced gray cast iron in high wear resistance automotive components such as cylinder liner and break disc

Penghasilan modul pembelajaran lukisan kejuruteraan berbantukan komputer

Perkembangan teknologi maklumat dalam dunia pendidikan tidak lagi boleh dinafikan pada masa kini. Keperluan yang meningkat dalam sistem pembelajaran dan pengajaran memerlukan mereka yang terlibat memberi sepenuh tumpuan terhadap mata pelajaran bagi mencapai matlamat. Untuk tujuan ini Modul Pembelajaran Lukisan Kejuruteraan berbantukan Komputer dihasilkan bagi membantu memudahkan pelajar dalam mata pelajaran Lukisan kejuruteraan. Statistik deskriptif digunakan dalam mengumpul dan menganalisis data. Secara keseluruhannya dari hasil kajian, menunjukkan para pelajar memberikan maklum balas yang positif terhadap modul ini. Semua responden memberi tindak balas positif terhadap modul dari segi mesra pengguna, isi kandungan, motivasi dan daya kognitif. Hasil dari kajian ini, didapati bahawa kebanyakan pelajar berminat terhadap Modul Pembelajaran Lukisan Kejuruteraan Berbantukan Komputer. Walau bagaimanapun masih terdapat beberapa aspek yang perlu diperbaiki untuk memantapkan modul ini

Multiband monopole antenna for mobile applications

— In this paper, a multiband monopole antenna has been proposed for mobile applications. The monopole antenna has simple structure with a physical size of 15 cm × 7 cm. The antenna consists of monopole shape loaded by a set of folded arms with a varying length which lead to a better impedance matching result and multiband performance. The simulated results show that the proposed antenna provide multiband frequency operation of 0.8 GHz, 1.8 GHz 2.1 GHz, 2.6 GHz and 3.5 GHz which covers the range from 0 to 4 GHz. The antenna is designed to operate at sub-6 GHz which proposed as lower frequency band to deliver 5G in early stage. The designed antenna has been fabricated and measured to validate the simulated results. RF Coaxial U.FL Connector was used as the port connector. The measurement results agrees well with the simulated ones for all frequency bands

Optimum transmitter receiver ratio for maximum wireless energy transfer

Due to high demand of using cordless mobile device, the interest in wireless energy transfer (WET) has been growth intensively. This paper presented a method to obtained optimum transmitter receiver ratio for maximum performance of WET system using different initial antenna size at various distance. An optimized algorithm has been developed to determine the optimum ratios that yield the highest wireless transfer efficiency (WTE) at near field communication (NFC) frequency, 13.56MHz. 30mm × 30mm single square loop antenna is used as initial size of both transmitter and receiver using FR4 with operating distance = 50mm. Operating distance and initial size of the antenna will be varied and the effect to the WTE will be studied using Matlab, verified using Microsoft Studio CST. At distance = 50mm and initial size of the antenna = 30mm × 30mm, optimum transmitter to receiver ratio equal to 1:3 is obtained. The pattern of optimum transmitter receiver ratio between Matlab and CST has met an agreement. This research limited to integer transmitter receiver ratio used only and no decimal number being involved in magnify the transmitter size