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29 record(s) found

Hubungan di antara minat, sikap dan kemahiran penggunaan perisian pembaca skrin dengan pencapaian literasi komputer pelajar bermasalah penglihatan

Mohd Farid Abdul Azis

Abstract

Kajian ini menentukan hubungan antara faktor minat, sikap dan kemahiran penggunaan perisian pembaca skrin (JAWS) dengan pencapaian dalam pembelajaran literasi komputer dalam kalangan pelajar bermasalah penglihatan. Kajian kuantitatif ini melibatkan 104 orang pelajar di pusat latihan Gurney, Brickfields Kuala Lumpur. Statistik deskriptif, pekali korelasi Pearson dan analisis regresi berganda digunakan untuk menganalisis data. Dapatan kajian menunjukkan ketiga-tiga pembolehubah tak bersandar iaitu, minat (r=.65, p..

Thesis Published 2017 1222 hits Available

Optical and thermal properties of TeO2-B2O3-Gd2O3 glass systems

Muhammad Noorazlan Abd Azis

Abstract

New glass samples with composition (1 – x)[(TeO2)70(B2O3)30] – x(Gd2O3) with x = 0.2, 0.4, 0.6, 0.8 and 1.0 in mol% have been synthesized by conventional melt-quenching techniques. X-ray diffraction (XRD) studies were performed in order to confirm the amorphous nature of the samples. The density of the samples has been found to vary with the Gd2O3 content, whereas an opposite trend has been observed in the molar volume. The analysis of Fourier Transform Infrared (FT-IR) spectroscopy of the samples showed that the glass network is mainly built of TeO3, TeO4, BO3 and BO4 units. The addition of Gd2O3 changed the refractive index, optical band gap and Urbach energy of the glass samples. The thermal properties of the studied glasses were investigated by measuring the thermal diffusivity of the samples by using photoflash method at room temperature..

Article Published 2019 1520 hits Available

Optical and structural properties of rice husk silicate incorporated borotellurite glasses doped with erbium oxide nanoparticles

Muhammad Noorazlan Abd Azis

Abstract

A system of erbium oxide nanoparticles doped rice-husk-silicate borotellurite glasses with compositional formula, {[(TeO2)0.7 (B2O3)0.3]0.8 (SiO2)0.2}1−y (Er2O3 NPs)y with y = 0.01, 0.02, 0.03, 0.04 and 0.05 was fabricated using the method of melt-quenching. Various characterizations and measurement techniques such as density and molar volume, X-ray diffraction, Fourier transform infrared, transmission electron microscopy and UV–Vis spectroscopy were carried out to study the structural, morphological and optical properties of the fabricated glasses. The density values for the glasses increased from 4.1900 to 4.6003 g cm−3 with the addition of 1% to 5% of Er2O3 NPs in the glass structure. The increase can be ascribed to increase in the overall molar weight of the glass caused by the higher molecular weight of erbium. The microstructural nature revealed in the glass morphological evidence of nanoparticle agglomerations in the glasses. From the UV–Vis spectra both direct and i.....

Article Published 2019 1084 hits Available

Dielectric behavior in erbium-doped tellurite glass for potential high-energy capacitor

Muhammad Noorazlan Abd Azis

Abstract

The use of erbium ions, Er3+ to enhance the dielectric properties is investigated in tellurite glass system for the frst time, tothe best of our knowledge. A glass series of tellurite glass with chemical composition, {[(TeO2)70(B2O3)30]70(ZnO)30}100−y(Er2O3)y (y = 0, 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05) was fabricated via melt-quenched technique. The X-ray difraction and Fourier transform infrared spectroscopy analysis proved the amorphous structure and the formation of nonbridging oxygen in the glass system. The Er3+ ions afect greatly to the dielectric constant, ε′ in which the dielectric constant, ε′ show high value at a lower frequency and higher temperature (above 110 °C). The reduction of dielectric constant, ε′ is found with the increment value of frequency, which corresponds to the formation of the hindrance efect on heavy dipoles caused by the mixed transition-ion efect. Meanwhile, the dielectric constant, ε′ is enhanced with the increase of temperature. The .....

Article Published 2019 1397 hits Available

Incorporation of electrochemically exfoliated graphene oxide and TiO2 into polyvinylidene fluoride-based nanofiltration membrane for dye rejection

Muhammad Noorazlan Bin Abd Azis

Abstract

In this work, the novel direct synthesis method of dimethylacetamide-based graphene oxide (GO) was performed through electrochemical exfoliation assisted by commercially available single-tail sodium dodecyl sulphate (SDS) surfactant. Then, the synthesised GO (SDS–GO) was incorporated into polyvinylidene fluoride (PVDF) solution to produce a nanofiltration (NF) membrane through the phase immersion method. The addition of GO into the preparation of membrane solution alters the membrane morphology and improves the hydrophilicity. TiO2 was also used as an additive for the NF membrane fabrication to further increase the membrane hydrophilicity. The fabricated PVDF/SDS–GO/TiO2 and PVDF/SDS– GO NF membranes were compared with pure PVDF membrane. Then, the fabricated NF membranes were tested for methylene blue (MB) rejection with 10 ppm MB concentration. On the basis of the dead end cell measurement operated at the pressure of 2 bar, the PVDF/SDS–GO/TiO2 presents high MB rejection (92......

Article Published 2019 2156 hits Available

Enhanced optical performance of tellurite glass doped with samarium nanoparticles for fiber optics application

Muhammad Noorazlan Bin Abd Azis

Abstract

We report on the optical efficiency of samarium nanoparticles (NPs) doped tellurite glasses experimentally, for the first time to the best of our knowledge. A high optical efficiency of samarium NPs doped tellurite glasses stable against crystallization was fabricated via melt- quenched technique. In particular, this work underlines the enhancement of optical properties with increasing samarium NPs concentration and the change of polarizability of tellurite glass network with the presence of samarium NPs. Using X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) analysis and transmission electron spectra (TEM), the amorphous arrangement, structural assignments and particle size had been revealed. The optical performance of samarium NPs doped tellurite glass was characterized by EL X-02C high accuracy ellipsometer and UV-Vis spectrophotometer. Based on ellipsometer and UV-Vis spectrophotometer, the refractive index was found slightly increases meanwhile the optical band .....

Article Published 2019 1178 hits Available

Upconversion properties of erbium nanoparticles doped tellurite glasses for high efficient laser glass

Muhammad Noorazlan Bin Abd Azis

Abstract

Erbium nano particles (NPs) doped tellurite glasses were prepared via melt-quenched technique and their chemical composition are as follows; {[(TeO 2 ) 0.70 (B 2 O 3 ) 0.30 ] 0.7 (ZnO) 0.3 } y (Er 2 O 3 NPs) 1−y , y = 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05. The amorphous state of the glass system was revealed and the structural parameters indicating the formation of non-bridging oxygen was shown. The current work underlines the spectral parameters from Judd–Ofelt (JO) studies, and upconversion spectra. The existence of erbium NPs was found experimentally using transmission electron microscopy (TEM). The Judd–Ofelt analysis suggests that the radiative probability, A rad is strong at ² H 11?2 —> ? I 15?2 and a longer lifetime at ? I 11?2 —> ? I 15?2 . The Argon laser beam was used to determine the upconversion emission peaks. The upconversion radiation emission excited at 800 nm was found in the range 390 nm. ..

Article Published 2019 1089 hits Available

Voltammetric sensors of bisphenol A, uric acid, dopamine and acetaminophen using layered double hydroxide modified multiwalled carbon nanotubes paste

Nurashikin Abd Azis

Abstract

This study aimed to develop a voltammetric sensor for the determination of bisphenol A (BPA), uric acid (UA), dopamine (DA) and acetaminophen (ACT) using multiwalled carbon nanotubes incorporated with zinc/aluminium layered double hydroxidequinmerac (Sensor 1), zinc/aluminium layered double hydroxide-quinclorac (Sensor 2) and zinc/aluminium layered double hydroxide-clopyralid (Sensor 3). The surface morphological was determined using field emission scanning electron microscope. The electrochemical properties were characterized by cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy. Several experimental variables of voltammetric analysis such as composition ratios, type of supporting electrolyte, pH of the solution and square wave voltammetry parameters were optimized. The effective surface area of electrodes was determined by chronocoulometry. At the optimum conditions, Sensor 1 showed three linear ranges for the single determination of BP.....

Thesis Published 2021 2381 hits Available

Black shale ore of Big Karatau is a raw material source of rare and rare earth elements

Muhammad Noorazlan Abd Azis

Abstract

The ores of Big Karatau are a valuable, currently unused source of rare and rare earth elements (REEs). To develop an integrated technology for processing black shale ore, it was studied using chemical, X-ray phase, infrared, mineralogical, X-ray spectral, and electron microscopic analyses. Rare and particularly REEs in the ore are found in various minerals in the form of inclusions in the siliceouscarbonaceous matrix. This explains the failures of the previously proposed processing methods, which either resulted in the incomplete extraction of the valuable components or were not profitable. For more complete extraction, novel ore processing approaches are required. A method for the early development of the original black shale ore using sintering with (NH4)2SO4 in the presence of concentrated H2SO4, followed by leaching of the cake with a diluted H2SO4 solution, is proposed. The optimal conditions for each stage are determined. The kinetic dependencies of the extraction of rare and .....

Article Published 2021 1062 hits Available

Comprehensive comparison on optical properties of samarium oxide (micro/nano) particles doped tellurite glass for optoelectronics applications

Muhammad Noorazlan Abd Azis

Abstract

Rare-earth oxides microparticles doped tellurite-based glass have been studied extensively to improve the capability of optoelectronic devices. We report a detailed comparison between two sets of glass series containing samarium microparticles and nanoparticles denoted as ZBTSm-MPs and ZBTSm-NPs, respectively. The two sets of glass have been successfully fabricated via melt-quenching technique with chemical formula {[(TeO2)0.70 (B2O3)0.30]0.7 (ZnO)0.3}1?y (Sm2O3 (MPs/NPs))y with y = 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05 mol fraction. The TEM analysis confirmed the existence and formation of nanoparticles in ZBTSm-NPs glasses. The density of ZBTSm-NPs glasses was found higher than ZBTSm-MPs glasses due to the distributions of nano-scale particles in tellurite glass network. There was a linear trend of increment in the refractive index in both sets of glass series along with the concentrations of dopants. The refractive index of ZBTSm-NPs glasses was found higher than ZBTSm-MPs glasses .....

Article Published 2021 1558 hits Available

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