bluuebunny/crossref_metadata_2025 huggingface dataset:
Multivariate Analysis of Composition Features to Perform Linear Predictions of Rubber Blends Tensile Strength
Authors: Fernandez Martinez Roberto , Jimbert Pello , Okariz Ana , Guraya Teresa
Published: October 2017

The goal in this work is to build a multivariate linear model to predict tensile strength since is one of the most significant mechanical properties of carbon-black reinforced rubber blends. This model is based in the relationship between the final mechanical properties and the material composition, with the advantage of using this model to improve the design of the composition of the blend. In order to predict this relevant physical attribute of rubber blends a linear regression is performed, but previously a multivariate analysis of the data is done to get a better accuracy in the validation of the model. The number of used instances and the values are determined by a Taguchi design of experiments, and the output values are obtained from the tensile strength test following the corresponding standard. After the performance of the multivariate analysis where the input variables are under a detail study, a selection of the best features help to improve the accuracy of the model, passing from a 24.80% to a 20.60% of error.
Luminescence Emission in Borotellurite Glass Containing Manganese Nanoparticles Doped Eu3+ Ions
Authors: Aziz Siti Maisarah , Sahar Md Rahim
Published: October 2017

A series of europium doped magnesium borotellurite glasses embedded with manganese nanoparticles (Mn3O4 NPs) of composition (59-x)TeO2-30B2O3-10MgO-x1Eu2O3-1Mn3O4 with 0.5 ≤ x ≤ 1.5 mol % are prepared using melt quenching technique. The existence of broad hump in X-ray diffraction (XRD) pattern verifies the amorphous nature of glasses. The presence of Mn3O4 NPs with average diameter of ~11 nm and (1 0 3) lattice plane having 0.276 nm spacing in the glass matrix is confirmed by high resolution transmission electron microscope (HRTEM) image. The glass samples are excited under 390 nm excitation wavelength and the emission spectra are found to consist of four emission peaks centred at 587 nm, 610 nm, 651 nm and 700 nm assigned to the transition from 5D0 →7FJ (J = 1, 2, 3, 4) states. The schematic energy level diagram is proposed. All results will be discussed with respect to the composition of Eu3+ ion.
Influence of Eu3+ on Physical and Thermal Properties of Borotellurite Glass Containing Manganese Oxides Nanoparticles
Authors: Sahar Md Rahim , Aziz Siti Maisarah , Sulhadi K.
Published: October 2017

The influence of the europium concentration on the physical and thermal properties of manganese nanoparticles (Mn3O4 NPs) ) embedded borotellurite glass are studied. Glasses with composition (59-x)TeO2-30B2O3-10MgO-xEu2O3-1Mn3O4 (where x = 0.5, 1.0 and 1.5 mol%) are prepared by melt-quenching method and characterized using XRD and Differential Thermal Analysis (DTA). The XRD pattern confirms the amorphous nature of all samples.The physical properties such as density (ρ) and molar volume (Vm) are calculated. The thermal properties of borotellurite glasses show that the glass with 1.0 mol % of Eu2O3 possess the highest stability.
Synthesis and Characterization of Cullet-Clay-Titanium Nitride Ceramic
Authors: Sayadi S.H.M. , Sahar Md Rahim , Sazali E.S.
Published: October 2017

A series of ceramic based on (x) titanium nitride- (60-x) cullet-40 kaolin clay, (where 0≤x≤6 wt%) has successfully been made by dry pressing technique followed by sintering at 1000 o C. The actual composition of ceramic is analyzed using Energy Dispersive of X-Ray (EDAX) while the phase existence is determined using X-Ray Diffraction (XRD) technique. Their microstructural morphology is observed under Field Emission Scanning Electron Microscope (FESEM) and the physical properties are determine in term of their density and hardness. It is found that the ceramic contain mostly of Silica and the phase occurrence is dominated by two major phases namely, quartz and tridymite. The structural morphology is observed to be in the form of dendrite structure, with the size become larger as cullet content is decreased. The density is found in the range of 1.941-3.019gcm -3 while the hardness is in the range of 1.174-1.773GPa depending on composition level.
Effect of Dysprosium Nanoparticles on the Optical Properties of Zinc Borotellurite Glass Systems
Authors: Ami Hazlin M.N. , Halimah Mohamed Kamari , Mohammad Farah Diana , Faznny M.F. , Iskandar Shahrim Mustafa
Published: October 2017

The glass samples of zinc borotellurite glass doped with dysprosium nanoparticles with chemical formula TeO20.7B2O30.30.7ZnO0.31-xDy2O3x (where x= 0.01, 0.02, 0.03, 0.04 and 0.05 molar fraction) have been fabricated by using melt quenching technique. In this study, the structural and optical properties of the zinc borotellurite glass doped with dysprosium nanoparticles were characterized by using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and UV-Vis spectroscopy. From the XRD, the amorphous nature of the glass samples has been confirmed. The infrared spectra revealed four obvious bands which are assigned for BO3, BO4 and TeO4 vibrational groups. The direct and indirect optical band gap, as well as Urbach energy, was calculated through absorption spectra obtained from UV-Vis spectroscopy. From the spectra, it is observed that both direct and indirect optical band gap decreases as the concentration of dysprosium nanoparticles increase. Other than that, the Urbach energy is observed to have an inverse trend with the optical band gap. The Urbach energy is increases as the concentration of dysprosium nanoparticles increases.
Synthesis, Structural and Optical Properties of Cerium Oxide Nanoparticles Prepared by Thermal Treatment Method
Authors: Baqer Anwar Ali , Matori Khamirul Amin , Al-Hada Naif Mohammed , Shaari Abdul Halim , Saion Elias , Chyi Josephine Liew Ying
Published: October 2017

A sample thermal treatment technique was utilised to synthesis cerium dioxide (CeO2) nanoparticles, using cerium (111) nitrate as a precursor, Polyvinylpyrrolidone as a capping agent, and deionized water as a solvent. The product underwent calcination treatment of 500, 550, 600, and 650 1C to crystallize the nanoparticles and to remove organic compounds. It was verified by XRD that by varying the calcination temperature, the cubic fluorite structure of CeO2 nanoparticles with pure products was achieved. Furthermore, the crystal sizes of the CeO2 nanoparticles were assessed to be 4 nm for the lowest calcination temperature and 23 nm for the highest calcination temperature. The FESEM micrographs of the CeO2 nanoparticles revealed a structure of CeO2 nanospherical that exhibited a tendency to amalgamate at higher calcination temperatures. The optical characteristics that were evaluated with the help of a UV-Vis spectrophotometer indicated a decrease in the band gap energy with an increase in calcination temperature as a result of the increase in the crystal sizes.
Properties of Silicon Carbide Polytypes under High Pressure Influence Calculated Using DFT
Authors: Emhemed Alham Mohamed M. , Zabidi Noriza Ahmad , Rosli Ahmad Nazrul
Published: October 2017

Theoretical molecular dynamic simulations based on plane-wave and pseudopotential density functional theory (DFT) calculations with CASTEP code were employed to explore the pressure influence on the properties of silicon carbide polytypes. The changes in lattice and electronic structures of 2H-, 4H-, and 6H-SiC polytypes at room temperature were investigated when pressures from 10 GPa to 200 GPa were applied. It’s found that the applied pressures didn’t cause a change in the hexagonal structure of the crystals, however the structural and electronic properties clearly affected by the compression. The dependences of volume reduction (V/Vo) and lattice parameters (a and c) on pressure were obtained successfully. The lattice parameters of the polytypes and c/a ratio showed a same trend under the compression with a clear similarity between 4H and 6H. The total energy-volume and enthalpy-pressure relations were estimated. The calculated energy gaps showed a reduction in the band gap width of 4H and 6H with the pressure increase while 2H band gap increased gradually with pressure. The tendency toward decreasing the density of state (DOS) at the conduction band edge was similar among the polytypes.
Luminescence from Erbium Doped Tellurite Glass: An Insight on Titania Nanoparticles Surface Plasmon Mediation
Authors: Ghoshal Sib Krishna , Yusof N.N. , Arifin Ramli , Awang Asmahani
Published: October 2017

Weak stimulated emission cross-section of rare earth ions (REIs) as dopants inside various glass hosts are disadvantageous for practical applications and needs improvement. We determine the mechanism of Titania (TiO2) nanoparticles (TNPs) mediated Surface Plasmon Resonance (SPR) assisted modification in the spectral properties of tellurite glass doped with Erbium (Er3+) ions. Transparent and thermally stable glass samples with varying TNPs contents are synthesized using melt-quenching technique. TEM images revealed the existence of TNPs with average size ranged from 16 to 26 nm. Glass containing 0.4 mol% of TNPs displayed an enhancement in the Raman signal by a factor of 2.25, 1.83, 1.98, 1.56 and 3.58 for the bands centered at 388, 495, 673, 758, and 845 cm-1, which is attributed to the SPR assisted effects. Absorption spectra of TNPs embedded glass (devoid of erbium ions) manifested two surface plasmon (SP) bands at 552 and 580 nm. Up-conversion (UC) PL spectra showed three prominent bands centered at 525, 545, and 660 nm due to the Er3+ ion transition from the excited states to the ground state. Furthermore, glass containing 0.4 mol% of TiNPs exhibited an intensity enhancement by a factor of 30, and 28.57 (green bands) and 19.60 (red band), which are ascribed to the generation of strong local electric field mediated by SPR effect of TNPs situated in the vicinity of Er3+ ion. The presence of TNPs surface plasmon is asserted to be responsible for the alteration of the Er3+ ions absorbance and modification of the UC emission intensity. A correlation between SPR and Surface Enhance Raman Scattering (SERS) is established.
Intrinsic Restructuring of Defects in Amorphous SiO2 in Manipulating Electron-Trapping Levels via First Principles Study
Authors: Halim S.N.M. , Nor R.M. , Taib Mohamad Fariz Mohamad , Razaki Nurul Iznie , Mohd Yusoff Mohd Hanapiah , Abd-Rahman M. Kamil
Published: October 2017

A model of undefected and defected amorphous SiO2 has been constructed from Rietveld Refinement to investigate the effect of defect structure to its properties. Atomic level study for both structure were carried out using plane-wave pseudo potential by density functional theory. A new electrons trapping energy level appears within the 5.853eV band gap of a-SiO2 for oxygen-excess defected structure. This defect energy level reduces as more number of excess oxygen atoms was added to the structure of a-SiO2. A spectral emission at 388nm from SiO2 glass excited with 350nm (200mW) laser demonstrates the existence of the defective states in the structure in trapping electron at 3.273eV energy level.
First Principles Study on Phonon Energy in SiO2 Glass with the Incorporation of Al2O3
Authors: Nor R.M. , Halim S.N.M. , Taib Mohamad Fariz Mohamad , Ibrahim Abdel Baset M.A. , Abd-Rahman M. Kamil
Published: October 2017

The aim of this study is to investigate the incorporation of Al2O3 in SiO2 glass with emphasis on reducing the phonon energy in the SiO2 matrix. Pure SiO2 glass has very high phonon energy of about 1100 cm-1, while Al2O3 has 780 cm-1. By incorporating Al2O3 into SiO2 glass structure, the relative phonon energy of the SiO2 matrix is expected to reduce. However, the composition of Al2O3 has been limited to a desired amount so as not to perturb other properties of SiO2, such as optical absorption. The Infrared (IR) spectra for a portion of SiO2 glass with the Al dopants were simulated at different molar ratio of the composition using Molecular Mechanic and Density Functional Theory (DFT). The Al2O3-SiO2 structures show a significant change in the simulated IR spectra compared to pure SiO2 glass. The Al2O3-SiO2 structures in the present work were constructed by replacing some Si atoms with Al atoms in the host lattice of SiO2 glass. In addition, some O atoms were removed from SiO2 host lattice to get the correct chemical balance. With increasing of Al2O3 content, the relative intensity of ~1100 cm-1 band associated with the asymmetrical O-Si-O/Si-O stretching vibrations is decreased. The decreasing in relative intensity of the IR spectra demonstrates that Al dopants are forming – [Al-O-Si] – linkages in the structure.
Structural, Thermal and Optical Studies of Bismuth Doped Multicomponent Tellurite Glass
Authors: Kaky Kawa M. , Lakshminarayana G. , Baki S.O. , Halimah Mohamed Kamari , Mahdi M.A.
Published: October 2017

In this communication, structural, thermal and optical absorption properties of bismuth doped multicomponent tellurite glass (69TeO2-10ZnO-10WO3-5Na2O-5TiO2-1.0Bi2O3 (mol %)) synthesized using melt quench method is reported. The X-ray diffraction confirms the amorphous structure of the synthesized glass. IR spectrum of bismuth doped glass show band at 601 cm-1. Raman analysis observed mainly in four spectral regions which are R1 (65-150) cm-1, R2 (280-550) cm-1, R3 (880-950) cm-1 and R4 (916-926) cm-1 and identified bands are assigned to respective molecular groups. Thermogravimetric analysis profile show stability regarding to weight loss. Differential scanning calorimetry indicates good thermal stability of the synthesized glass for its applications in optical fibers. The absorption spectrum identified the cutoff wavelength at 430 nm.
Synthesis of BaTiO3 Nanoparticles via Hydrothermal Method
Authors: Hasbullah Nurul Norfarina , Lee Oon Jew , Chyi Josephine Liew Ying , Chen Soo Kien , Talib Zainal Abidin
Published: October 2017

In this work, BaTiO3 nanoparticles were synthesized through hydrothermal method. The powder obtained from the hydrothermal process (as-synthesized powder) was calcined at 1000 °C. The phase formation and morphology of the as-synthesized and calcined powders were studied using X-ray diffraction (XRD), thermogravimetric (TGA) and differential scanning calorimetry (DSC) analyzer, and transmission electron microscope (TEM). The XRD data showed that the as-synthesized powder is partially amorphous. Upon calcining the powder at 1000 °C, highly crystalline BaTiO3 with tetragonal structure was obtained. As shown by TGA and DSC analysis, the precursor powder was completely transformed into BaTiO3 at 1000 °C. The presence of BaCO3 as an impurity phase in the powder is due to the lack of Ba2+ / Ti3+/4+. Transmission electron microscope images showed that the particle size of the as-synthesized powder increased after calcination due to crystal growth. In addition, nanocubes with the average size of around 11.66 nm were obtained as a result of the calcination compared to the ellipsoid like particles of the as-synthesized powder.
Optical Properties of Silica Borotellurite Glass Doped with Manganese Oxide
Authors: Zaitizila I. , Halimah Mohamed Kamari , Mohammad Farah Diana , Nurisya Mohd Shah
Published: October 2017

Silica borotellurite glasses doped with manganese oxide with chemical formula {[(TeO2)0.7(B2O3)0.3­]0.8[SiO2]0.2}1-x{MnO2}x (where x = 0.0, 0.01, 0.02, 0.03, 0.04 and 0.05 molar fraction) were fabricated. Silica were extracted from the burning process of rice husk. Glass samples were prepared by using the melt-quenching technique. The FTIR spectra showed that the addition of MnO₂ contributed to the transformation of TeO4 to TeO3. The diffraction pattern of XRD showed a broad hump which indicates the amorphous nature of the samples. The result for both optical band gap and Urbach energy showed decreasing trend as the concentration of manganese increased.
Microstructural and Nonlinear Properties of Zn-V-Mn-Nb-O Varistor Ceramics with Gd2O3 Substitution for Low Voltage Application
Authors: Isa Nor Hasanah , Azmi Zakaria , Azis Raba’ah Syahidah , Rizwan Zahid
Published: October 2017

The effect of Gd2O3 substitution on the microstructural and electrical properties of Zn-V-Mn-Nb-O varistor ceramics sintered at 900°C was investigated. XRD, SEM, and EDAX results show that the GdMnO3 and GdVO4 phases formed at the grain boundaries and triple point junctions. Gd2O3 substitution inhibited the grain growth from 3.85 to 3.06 μm and increased the sintered ceramics density from 5.12 to 5.19 g/cm3.The samples containing the amount of 0.03 mol% Gd2O3 exhibit an optimum nonlinear coefficient α value which is 9.91, highest breakdown electrical field which is 88.48 V/mm and lowest leakage current density which is 0.11 mA/cm2 in low voltage application.
DC and Thermal Conductivity of Lithium Zinc Phosphate Glasses
Authors: Hilman A.M. , Sazali E.S. , Sahar Md Rahim , Azman K. , Norihan Yahya
Published: October 2017

The phosphate glasses, with composition (60-x)P2O5-25ZnO-(15+x)Li2O where 0.0 ≤ x ≤ 5.0 mol% are prepared by conventional melt quenching method. The amorphous nature of the glass is determined by X-Ray Diffraction (XRD). The physical properties are measured in term of their density and molar volume. Glass density is found to increase from 2.700 to 2.785 g cm-3 whereas molar volume is found to decrease from 40.735 to 37.488 cm3 mol-1 with respect to Li2O content. The DC measurements are done by using four point probes and the activation energies are determined. Arrhenius plot shows straight line behavior as observed that confirmed the conductivity increased with Li2O content. The activation energy is found to decreases from 0.75 to 0.08 eV as Li2O content is increased in the temperature range from 310 to 420 K. Measurements of the thermal conductivity using Lee’s disc apparatus have been made. It is observed that the maximum and minimum thermal conductivity are 0.2679 and 0.2168 W m-1 K-1 respectively.
Influence of Sol-Gel pH and Soaking Time on the Morphology, Phases and Grain Size of TiO2 Coating
Authors: Johari Nur Dalilah , Mohd Rosli Zulkifli , Juoi Jariah Mohamad , Musa Muharniza Azinita
Published: October 2017

Titanium oxide, (TiO2), can exist in three distinct crystallographic phases known as anatase, rutile, and brookite. Brookite, however, is the least known TiO2 phases and usually exists as byproduct during synthesising rutile or anatase. Therefore, in this study, the influence of sol-gel pH and soaking time on surface morphology, phases and grain size of TiO2 coating were investigated in an attempt to develop brookite thin film. Titanium (IV) isopropoxide (TTiP) is used as precursor for preparing TiO2 sols. Prior to heating, TiO2 layers were deposited on a glass slide by dipping it five times into TiO2 sols. The TiO2 layers were then heated at 450°C and soaked for 1 and 3 hours to form TiO2 coating. Analysis on the phases and grain size were carried out using X-ray diffraction (XRD). The TiO2 surface morphology was investigated using Scanning Electron Microscope (SEM). Results showed that brookite phase with grain size of 27.40 nm successfully deposited on glass slide from sols with pH12. Conversely, the TiO2 coatings deposited from sols of pH1 and pH7 are amorphous. The effect of soaking time on phases and grain size is insignificant but enhances coatings uniformity as the soaking time increased. Thus, it can be concluded that sol-gel pH affect TiO2 crystallinity and phases. Brookite film is develop only when the TiO2 sols is in bases condition or at higher pH value.
Synthesis and Optical Characterization of Zinc Borotellurite Glass Doped with Lanthanum Nanoparticles
Authors: Faznny M.F. , Halimah Mohamed Kamari , Latif Amirah Abdul , Iskandar Shahrim Mustafa
Published: October 2017

A glass series with chemical composition of {[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}1-x (La NPs)x where x = 0.01, 0.02, 0.03, 0.04 and 0.05 molar fraction was synthesized through conventional melt-quenching method. The fabricated glasses were characterized by using UV-Vis and FTIR technique in the range of 220 to 800 nm and 280 to 2000 cm-1 respectively. Various absorption bands that were recorded in FTIR spectra indicates the presence of TeO4, BO3 and BO4 unit. In this research, indirect energy band gap showed an increasing trend while refractive index values decreases as amount of La NPs increases due to the decrement of high polarizability nonbridging oxygen number in the glass system. Other optical parameter that also take part in governing the value of refractive index such as electronic polarizability was also determined.
Growth of Copper Nanowires by Using Thermal Oxidation for Solid Oxide Fuel Cell
Authors: Rahman N.A.A. , Muhammad Rosnita , Ibrahim Zuhairi , Wahab Yussof
Published: October 2017

Tuning high density nanostructures by simple and economic method may contribute towards the development of solid oxide fuel cells. Copper oxide nanowires grown on Cu foil by thermal oxidation at relative low operating temperature from 400°C are characterized by using x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), atomic force morphology (AFM), conductive-AFM (C-AFM), and field emission scanning electron microscopy (FESEM). The role of oxidizing temperature and time on structural and electrical properties are studied. The formation of nanowires is confirmed by X-Ray diffraction pattern with the presence of copper oxide. The electrical conductivity of the nanowires was ranging from 0.2x105 S m-1 to 0.8x105 S m-1are determined from conductive atomic force microscopy. The oxidation time strongly influence the morphology and chemical composition of the nanowires. Field emission scanning electron microscopy reveals the growth mechanism of copper nanowires formation is based on vapour-solid (VS) mechanism. Herein, the successfully growth of CuO nanowire are directly from Cu foil to overcome the mismatching stress between the substrate and the oxide layer. Optimum parameters are studied to make better electrolyte performance in the applications of solid oxide fuel cell (SOFC).
Hydrogen Gas Sensing Characterizations Based on Nanocrystalline SnO2 Thin Films Grown on SiO2/Si and Al2O3 Substrates
Authors: Haslan Abu Hassan , Kadhim Imad Hussein
Published: October 2017

High-quality nanocrystalline (NC) SnO2 thin films were grown on SiO2/Si and Al2O3 substrates using sol–gel spin coating method. The structural properties, surface morphologies and gas sensing properties of the NC SnO2 were investigated. XRD measurements showed a tetragonal rutile structure and the diffraction peaks for NC SnO2 thin films grown on Al2O3 substrates outperformed those of NC SnO2 films grown on SiO2/Si substrates. The surface morphology of the annealed SnO2 thin films at 500 °C appeared as polycrystalline with uniform nanoparticle distribution. Hydrogen (H2) gas sensing performance of the NC SnO2 was examined for H2 concentrations ranging from 150 ppm to 1000 ppm at different temperatures (room temperature, 75 and 125 °C) for over 50 min. The room temperature sensitivities for H2 gas sensors based on NC SnO2 thin films grown on Al2O3 and SiO2/Si substrates was 2570% and 600%, respectively upon exposure to 1000 ppm of H2 gas. While the sensitivity values at 125 °C increased to 9200% and 1950%, respectively.
Synthesis of Blue-Luminescence Graphene Quantum Dots Using Hydrothermal Method
Authors: Far’ain Noor , Salleh Muhamad Mat , Ashraf Muhammad , Abd Rahman Mohd Yusri , Umar Akrajas Ali
Published: October 2017

This paper described the synthesis of graphene quantum dot (GQDs) by hydrothermal method using graphene (average thickness of 7 nm) as a precursor material. At first, graphene was diluted in n-butyl acetate to obtain uniform mixture through sonication. Then, graphene was transferred into Teflon-lined autoclave and to be heated at different period of times to obtain resultant GQDs.The synthesised GQDs was characterized by using FT-IR Spectrometer (FTIR), UV-VIS Spectroscopy, photoluminescence (PL) and transmission electron microscopy (TEM). Typically, the absorption peak of GQDs were observed around 260 nm and 330 nm in UV-VIS spectra due to π →π * transition of aromatic sp2 domain. This GQD has a broad peak and emit strong PL, light centred at 440 nm upon excitation at 260 nm. Thus, blue-luminescent GQDs are demonstrated, with a material performance that is competitive with GQDs produced by other methods.
The Influence of Growth Duration Process on Morphology and Electrical Properties of SnO2 Nanostructured Films
Authors: Mohamed Ruziana , Md Salleh Khairunisa , Malek Mohd Firdaus , Mamat Mohamad Hafiz , Norihan Yahya , Khusaimi Zuraida , Mahmood Mohamad Rusop
Published: October 2017

Tin oxide (SnO2) nanostructured thin film with different immersion times was prepared on zinc oxide (ZnO) seeded catalyst using immersion method. The immersion times were varied at 3.0, 3.5 and 4.0 hours. Field emission scanning electron microscopy (FESEM) and two point probes current-voltage (I-V) measurements were used to study the surface morphology and electrical properties of SnO2 nanostructured thin films. The diameter size of SnO2 nanostructures which immersed at 3.0, 3.5 and 4.0 h were in range 10-20 nm, 20-30 nm and 30-50 nm, respectively. The results shows the highest electrical properties was at 3.0 h of immersion time.
Nanostructure of Al-ZnO Thin Films on ITO/Glass Substrate Prepared via Sol-Gel Spin Coating Process
Authors: Noorikalkenari Hassan , bin Deraman Karim
Published: October 2017

Solar energy is probably the most important source of renewable energy available today. ZnO is a potential material for the fabrication solar cell. Zinc oxide (ZnO) nano-structure semiconductors have been recently gained much attention in the electronic and optical device applications. ZnO is a compound semiconductor, which has a high extention band gap (E= 3.37 eV) at room temperature (RT) with a Wurtzite crystal structure. In particular ZnO can be employed as the transparent conducting oxide (TCO) in solar cell applications due to its high productivity, non-toxic, low cost, and excellent electrical conductivity. In this study, aluminum doped ZnO (AZO) polycrystalline films have been fabricated on ITO/substrates via a sol-gel spin-coating method. The quantity of aluminum doping in the solution was 4.0 %. After synthesis, the films were pre-heated at 300°C for 25 min and after that the films were inserted in a Tub-furnace and post-annealing at 450°C to 750°C for 1 h. The microstructural and structural properties of AZO films were studied through X-ray diffraction (XRD), UV-Vis NIR and scanning electron microscope (SEM) analysis. The TCO applications of the transmittance of samples were also examined. The results showed that the annealing temperature does not seriously affect on the transmittance of AZO films over the visible range.
Effect of Neodymium Ions on Density and Elastic Properties of Zinc Tellurite Glass Systems
Authors: Abdulbaset A.A. , Halimah Mohamed Kamari , Azlan M.N.
Published: October 2017

The aim of this work is to determine the effect of Nd3+ ion concentration on the elastic properties of zinc-tellurite glass for the development of waveguide lasers. A series of Neodymium doped zinc-tellurite (NZT) glass system of composition [(TeO2) 0.70 (ZnO) 0.30] (1-x) Nd2O3 (x), x =0, 0.01, 0.02, 0.03, 0.04 and 0.05, were synthesized by using conventional melt-quenching method. XRD analysis confirmed the amorphous nature of the glass; the FTIR confirmed the presence of TeO3 and TeO4 in the glass network. The density of the glass system increases with increase in neodymium concentration. The longitudinal ultrasonic velocity decreases from 3737.01 to 3045.23 ± 10 ms−1, and the shear velocity decreases from 1959.31 to 1887.81 ± 10 ms−1. The experimental results have shown that the elastic properties depend on the composition of the glass systems and the effect of neodymium (Nd2O3) within the glass network.
Magnetic and Microwave Properties of Polycrystalline Gadolinium Iron Garnet
Authors: Shafiee Farah Nabilah , Azis Raba’ah Syahidah , Ismail Ismayadi , Nazlan Rodziah , Ibrahim Idza Riati , Rahim Azdiya Suhada Abdul
Published: October 2017

The microwave loss in nanosized GdIG particles synthesized using mechanical alloying technique was investigated. There were very few of research on the microwave properties of nanosized particle GdIG and there is no attempt investigating on the material at C-band frequency range and its correlation with the microstructure. Gadolinium (III) iron oxide and iron (III) oxide, α-Fe2O3 were used as the starting materials. The mixed powder was then milled in a high-energy ball mixer/mill SPEX8000D for 3 hours. The samples were sintered at temperature 1200°C for 10 hours in an ambient air environment. The phase formation of the sintered samples was analyzed using a Philips X’Pert Diffractometer with Cu-Kα radiation. Complex permeability constitutes of real permeability and magnetic loss factor were measured using an Agilent HP4291A Impedance Material Analyzer in the frequency range from 10 MHz to 1 GHz. A PNA-N5227 Vector Network Analyzer (VNA) was used to obtain the information on ferromagnetic linewidth broadening, ΔH that represents the microwave loss in the samples in in frequency range of 4 to 8 GHz (C-band). The ΔH value was calculated from the transmission (S21) data acquired from VNA. The single phase GdIG showed low initial permeability and low magnetic loss when applied with low-frequency range energy. From these data, it is validated that GdIG is a suitable material for microwave devices for the high-frequency range.
Effects of Sodium Iodide (NaI) on Electro-Conductivity with Polyurethane-Diol Organic Electrolyte for Dye-Sensitized Solar Cell (DSSC)
Authors: Selamat Mohd Hamizan , Zakaria Rosnah , Ahmad Azizah Hanom
Published: October 2017

Dye Sensitized Solar Cells (DSSC) technology using inorganic electrolytes post problem in solvent evaporation and iodine sublimation (corroding contacts) causing instability of cells. Application of low molecular oligomers is progressing recently for an improved performance. The electrolyte system was aimed for improving electrochemical stability using quasi-solid-state electrolytes from organic capped polymers. A photo-electrochemical cell was developed from bio-based polyurethane diol (PU) polymer electrolyte with Sodium iodide (NaI) as conducting electrolyte transport material. In this study, polyurethane-diol was modified with NaI cations in the hydrothermal chemical reaction to form modified polyurethane-diol electrolyte. The chemical structure of polyurethane-diol and NaI have achieved highest conductivity of 8.06x10-5 S.cm-1 where structural of polyurethane-diol with NaI shown redox Fermi vectorial energy transfer evaluated for performance of efficiency. Stable cell for DSSC system require material properties to be invidually optimized in views of various elemential performances and solar cell of FTO/TiO-Pc/PU-NaI-I2/Ac give a response under light intensity of 100 mW cm−2 and indicated efficiency of power generation of 4 mW where photovoltaic effect of current density, Jsc of 0.04 mA.cm−2 and open circuit voltage, Voc of 0.4 V respectively.
Role of Horseradish Peroxidase in Polypyrrole Conductivity
Authors: Othman Siti Amira , Radiman Shahidan
Published: October 2017

Immobilise enzymes can offer many advantages over their soluble forms making this is a topic of active research in enzyme technology for industrial applications. There are various methods for enzyme immobilization as well as support materials. The methods and supports used for immobilisation of certain enzyme are chosen to ensure the highest retention of activity and its stability. Enzyme Horseradish peroxidise (HRP) was used extensively in molecular biology applications primarily for its ability to amplify a weak signal and increase the detectability of a target molecules. Recently class of conducting polymers are used as a polymeric support. Among the family a conducting polymer, polypyrrole (PPY) has intensively been used for various reason because of its unique properties such as ease of synthesis by chemical or electrochemical oxidative polymerization of the monomers, role as a polymeric support and also have potential in various field . It has alternating single and double carbon-carbon bonds along the polymeric chains. The highly conjugated polymer chain can be assigned reversible chemical, electrochemical and physical properties controlled by a doping/ de-doping process, which makes this polymers very attractive as transducer materials in various sensing devices. This paper reports the process of immobilised enzymes on polymeric substrate and the role of enzymes in PPY conductivity. The characterization was done using UV-Visible, FTIR and four point probe.
Acoustic Characterisation of Konjac Glucomannan Gel as a Medical Phantom
Authors: Mat Daud Anis Nazihah , Rohani Md Supar , Jaafar Rosly
Published: October 2017

Acoustic properties are the main criteria to evaluate the compatibility of tested materials as a medical phantom. We determined the acoustic properties of konjac glucomannan (KGM) gel to verify its compatibility as a medical phantom. The acoustic properties measurement employed ultrasonic insertion technique and utilized two identical transducers of 5 MHz center frequencies. One KGM gel block with 5.62 mm thickness was used as sample to determine its longitudinal speed, acoustic impedance and attenuation coefficient at three different water temperatures; (21.5 ± 0.1), (22.5 ± 0.1) and (23.5 ± 0.1) °C. Findings indicated that its longitudinal speed and acoustic impedance increased from (1495 ± 1) to (1499 ± 1) m s-1 and (1.555 ± 0.001) to (1.559 ± 0.001) × 106 kg m-2 s-1 as the water temperature increased from (21.5 ± 0.1) to (23.5 ± 0.1) °C. It also indicated that its attenuation coefficient varied around (0.1303 ± 0.0107) to (0.1373 ± 0.0103) dB cm-1 with increasing water temperature. KGM gel is compatible to be a medical phantom since its acoustic properties are comparable to the acoustic properties of human soft tissue.
Luminescence Studies of Erbium Doped Sodium Magnesium Boro-Tellurite Glass
Authors: Amiar Rodin Nur Liyana , Sahar Md Rahim
Published: October 2017

The optical behaviour of Er3+ (1.0 – 2.0 mol %) doped B2O3-TeO2- Na2O-MgO glasses synthesized by conventional melt-quenching technique was studied through luminescence measurements. The X-ray diffraction (XRD) pattern confirms the amorphous nature of the glasses without the existence of any sharp peak. The emission spectra at 378 nm excitation displayed three emission peaks corresponding to 2H11/2-4I15/2, 4S3/2-4I15/2 and4I9/2-4I15/2 transitions. Hence, a schematic energy level diagram was proposed. The luminescence properties of the prepared glasses was found to be strongly affected by varying the concentration of Er3+ ions.
A Comparative Analysis of Physical and Chemical Properties of Biochars and Bio-Oils Obtained from Pyrolytic Process of Mesocarp Fibre and Empty Fruit Bunch
Authors: Abdullah Nurhayati , Safana Aminu Aliyu , Sulaiman Fauziah , Abdullahi Ibrahim Inuwa
Published: October 2017

The fundamental objectives of this study is to analyzed and compare the physical and chemical properties of pyrolysis products (biochar and bio-oil) derived from two oil palm wastes. Empty fruit bunch (EFB) and mesocarp fibre (MF) were subjected to pyrolysis at a temperature of 400 °C for 2 hours holding time at 10 °C/min heating rate and with nitrogen flow rate of 2 L/min. The result obtained from raw material showed that MF contains a high quantity of hemicellulose and lignin which led to a high yield of bio-oil and biochar respectively, whereby, EFB contained a high content of cellulose. The high content of cellulose in EFB resulted in a high yield of gas compared to fibre. The higher heating value (HHV) of biochar and bio-oil were found to be 28.76 and 19.45 MJkg-1 for MF and, 24.33 and 19.98 MJkg-1 for EFB, respectively. Comparatively, the biochar obtained from MF material has high HHV than EFB material. However, all the biochars derived can be used for briquettes production as coal replacement in the future due to significantly high calorific value as compared to Malaysian sub-bituminous coal which has 24.6 MJkg-1. Furthermore, pyrolysis of any wastes encourages proper sanitation and lead to a healthy environment. It can also serve as a potential solution to the energy crisis in developing countries, Nigeria in particular if bio-oil can be improved to power electricity generation facilities in replacement to diesel.
Evanescent Field Study on a U-Shaped Silica Fiber Absorption Sensor Using Non-Sequential Ray Tracing
Authors: Rashid A.R.A. , Mokhtar Wan Maisarah , Dasuki Karsono A. , Ehsan Abang Annuar , Shaari Sahbudin
Published: October 2017

The ray tracing of unclad U-shape multimode fiber optic is examined by using Zemax simulation have been proposed. The influence of the geometry of sensing region such as absorbing medium refractive index, n2, shape of fiber and the bending radius is analyzed. Number of analysis ray is determined and the value of n2 is varied at 1, 1.3314, 1.359, 1.36, 1.37 and 1.4. The intensity of light propagate inside the fiber is reducing at high n2 and this graph pattern is supported by experimental result. A U-shaped sensor is used for the analysis because of the sensitivity is higher than straight fiber design due to their higher penetration depth. Zemax simulation shows that the fiber with bending radius 1.5 mm has higher response compared to fiber with radius 2.5 mm.
Hardness and Structure of Er3+:Sm3+ Co-Doped Oxychloride Zinc Tellurite Glass
Authors: Nazhirah Mazlan S.N. , Arifin Ramli , Ghoshal Sib Krishna
Published: October 2017

Glass samples with composition of (64-x)TeO2 + (x)ZnO + 15 ZnCl2 + 0.5 Sm2O3 + 0.5 Er2O3 (x = 20, 25 and 30 mol%) are prepared by melt quenching method. The season for co-doping with rare earth ions such as samarium (Sm3+) and erbium (Er3+) is to explore the feasibility of their simultaneous exploitation as high performing up-converted lasing materials. The role of varying modifier of ZnO concentration in improving the hardness and structural properties are evaluated. The density is observed to reduce and ionic packing density is augmented with increasing concentration of ZnO. Glass with 25 mol% of ZnO revealed the optimum hardness of 2830 N/mm2. Incorporation of Zn2+ into the tellurite host matrix is found to shift the IR bands position slightly without altering their intensity. Bonding vibrations corresponding to bending of TeO3 unit (784-762 cm-1), stretching of TeO4 units (678-676 cm-1) and Zn-O bonds (462-452 cm-1) are evidenced. Incorporation of ZnO as modifier is established to enhance the hardness and improved the structural properties. The proposed glass composition may be useful for industrial purposes.
Silver Nanoparticles Included Er3+/Sm3+ Co-Doped Phosphate Glass: Evaluation of Thermal Stability and Infrared Absorption
Authors: Misron S. Rashidah , Arifin Ramli , Ghoshal Sib Krishna
Published: October 2017

Three lithium-sodium-phosphate glass samples with molar composition of (48.5–x)P2O5-20Na2O-30Li2O-0.5Sm2O3-1.0Er2O3-xAgNPs (where x = 0.01 g, 0.03 g and 0.05 g) are prepared using melt quenching method. The thermal stability and infrared absorption of synthesized samples are evaluated as a function of Ag NPs contents. Thermal and structural characterizations are made using differential thermal analysis (DTA) and Fourier transformed infrared (FTIR) spectroscopy, respectively. Thermal stability is found to vary in the range of 171 °C to 197 °C. FTIR spectra revealed various characteristic bonding vibrations related to the glass network structures. The IR absorption band around 570 cm-1 is assigned to the P-O-P bending vibrations while the occurrence of bands around 759 cm-1 and 913 cm-1 are allocated to the P-O-P symmetric stretching vibrations. The asymmetric stretching vibrations of (PO3)2- and (PO2)- units are observed around 1045 cm-1 and 1254 cm-1 , respectively. The appearance of a band around 1735 cm-1 is allocated to the free H2O molecules because of moisture attack to the sample. Influences of Ag NPs in the host matrix are analyzed and explained.
Structures and Ligand Field Parameters of Sm3+ Doped Tellurite Glass: Gold Nanoparticles Mediation
Authors: Tanko Y.A. , Sahar Md Rahim , Ghoshal Sib Krishna
Published: October 2017

Controllable modifications of overall properties of rare-earth doped glasses via gold nanoparticles (Au NPs) mediation prompted gamut research interests. Such glass systems are interesting due to their technological prospects and well as fundamental understanding of surface plasmon resonance effects at metal glass interface responsible for diverse emerging attributes. This motivate us to determine the effects of varying concentration of Au NPs on the structure and ligand field parameters of samarium (Sm3+) doped zinc tellurite glass. Glass samples with composition (79-x)TeO2-20ZnO-1Sm2O3-xAuCl3, where 0 ≤ x ≤ 0.10 mol% are prepared using melt quenching method. X-ray diffraction pattern of all glasses confirmed their amorphous nature. Transmission electron microscopic images verified the existence of Au NPs in a glass matrix matrix with an average size of 10.52 nm. Two surface plasmons resonance band of gold are probed at 652 and 715 nm. Using the UV-Vis absorption spectral data, quantities such as nephelauxetic ratio, bonding parameter and Racah parameters are evaluated. Both bonding parameter and nephelauxetic ratio revealed a reduction with increasing concentration of Au NPs, where decrease in the ionic bonding between Sm3+ and surrounding ligand have clearly indicated an enhancement in the covalency. The values of Racah parameters are decreased as the concentration of Au NPs are increased. The observed reduction in the nephelauxetic function is attributed to the weakening of the localized d-electrons aroused from overlapping d-orbital and ligand orbital. Furthermore, the Raman spectra displayed the structural modification in terms of TeO4 trigonal bipyramidal (tbp) unit, where many TeO4 tbp units are converted into their TeO3 trigonal pyramid (tp) counterparts. Raman bands are found to be located around 102-105 cm-1, 420-424 cm-1, 657-661 cm-1 and 729-736 cm-1. Results are analyzed and compared. Present glass composition is asserted to be useful for the development of photonic devices.
Luminescence Properties of Cerium Doped Iron Calcium Boroaluminate Glass
Authors: Roslan S. Akmar , Arifin Ramli , Ghoshal Sib Krishna
Published: October 2017

Borate glass system of composition (100-x)B2O3-15Al2O3-20CaO-0.4Fe2O3-xCeO2 with x = 0, 0.25, 0.50, 0.75, and 1.0 mol% were prepared using conventional melt-quenching method. Optical measurements were carried out at room temperature to determine the Cerium (Ce3+) ions concentration dependent absorption and luminescence emission properties of such glass system. Optical energy band gap of the glass system were evaluated as a function of Ce3+ ions content. Indirect band gap energy was found to be lower than the direct band gap energy. Urbach energy was ranged between 0.12-0.17 eV. An increased broad absorption is observed in the UV region with increasing Ce3+ ions concentration. The emission spectra of the glass system recorded with 380 nm excitation wavelength revealed prominent cyan-green emission.
Reduction of Hygroscopicity in Zinc-Calcium-Phosphate Glass via Iron-Oxide Incorporation
Authors: Hamzah H. , Arifin Ramli , Ghoshal Sib Krishna
Published: October 2017

Despite several advantages of phosphate glass systems, their hygroscopic tendency (absorbing or attracting moisture from the atmosphere) remain a major limiting factor for widespread industrial applications. Dedicated efforts are made to improve the hygroscopic nature of such glasses for making them chemically durable and greatly resistant towards moisture attack. Guided by this requirement, we prepared five phosphate glass samples of composition (70-x) P2O5–xFe2O3–25ZnO–5CaO with controlled manipulation of iron-oxide contents (Fe2O3: x = 0 to 20 mol %) using melt-quenching method. The influence of Fe2O3 (as modifier) contents variation on the improvement of structural and chemical strength is determined. As-synthesized glass samples are immersed in acidic solutions for corrosion test. In this test, glass samples are engrossed in the aqueous hydrochloric acid (HCl) media at 90 °C and soaked for a period of 4 h. The corrosion rate (CR) was calculated from the weight loss obtained after the test. The least number of CR indicates that the inclusion of Fe2O3 in the glass network improved the network rigidity and made the glass much stronger as well as more water resistant. However, it is also established that there is an optimum limit of Fe2O3 content beyond which the durability cannot be further improved. The AFM analysis of pre- and post- chemically treated glass samples informed the surface roughness and 3D topography. Present observation must be validated with other supporting experiments and model calculation which is underway. In this study, it revealed that the lowest corrosion rate was sample S3 (10% of Fe2O3) which have CR value of 1.02±0.12 ´ 10-3gcm-2h-1 .
First Principles Investigation on the Structural, Electronic and Optical Properties of Amorphous Silica Glass
Authors: Nor R.M. , Halim S.N.M. , Taib Mohamad Fariz Mohamad , Abd-Rahman M. Kamil
Published: October 2017

The structural, electronic, and optical properties of an amorphous SiO2 (a-SiO2) model is investigated by using first-principles calculation. Most research works used beta-cristobalite glass structure as a reference to amorphous silica structure. However, only the electronic properties were been presented without any link towards the optical properties. Here, we demonstrate simultaneous electronic and optical properties, which closely matched to a-SiO2 properties by generating small sample of amorphous quartz glass. Using the Rietveld refinement, amorphous silica structure was generated and optimized using density functional theory in CASTEP computer code. A thorough analysis of the amorphous quartz structure obtained from different thermal treatment was carried out. The structure of amorphous silica was validated with previous theoretical and experimental works. It is shown that small sample of amorphous silica have similar structural, electronic and optical properties with a larger sample. The calculated optical and electronic properties from the a-SiO2 glass match closely to previous theoretical and experimental data from others. The a-SiO2 band gap of 5.853 eV is found to be smaller than the experimental value of ~9 eV. This is due to the underestimation and assumption made in DFT. However, the band gap value is in good agreement with the other theoretical works. Apart from the absorption edge at around 6.5 eV, the refractive index is 1.5 at 0eV. Therefore, this atomic structure can served as a reference model for future research works on amorphous structures.
Gold Nanoparticles Embedded Erbium-Lead-Tellurite Glass: Bonding Parameters Evaluation
Authors: Sazali E.S. , Sahar Md Rahim , Ghoshal Sib Krishna
Published: October 2017

Au NPs contents dependent modifications in the absorption and bonding parameters are inspected. Glass systems with composition (79-y)TeO2 – 15PbO – 5PbCl2 – 1Er2O3 – (y)AuCl3 where 0.0 ≤ y ≤ 0.1 mol% are prepared and characterized using X-ray Diffraction (XRD). The absorption characteristics of the glass are observed using UV-Visible-NIR (UV-VIS-NIR) spectrophotometer. XRD spectra confirm the amorphous nature of all samples. UV-VIS-NIR spectra reveal seven absorption bands centered at about 490, 526, 551, 652, 800, 982 and 1520 nm originating from 4I15/2 to 4F7/2, 2H11/2, 4S3/2,4F9/2, 4I9/2, 4I11/2 and 4I13/2 transitions, respectively. The low value of indicated an increase in the covalency and the positive sign of for all glass systems indicates the bonding between the RE ions and the surrounding ligand is covalent in nature.