bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of γ-Alumina-Supported Cobalt and Iron Nanocatalysts
Authors: Ali Sardar , Mohd Zabidi Noor Asmawati , Subbarao Duvvuri
Published: July 2012

The present work deals with the synthesis of cobalt monometallic and bimetallic Co/Fe nanocatalysts supported on alumina. The nanocatalysts were prepared by a wet impregnation method. The samples were characterized in terms of reducibility, dispersion, metal particle size, textural characteristics and crystallinity. These characteristics were revealed using hydrogen temperature-programmed reduction (TPR), CO-chemisorption, transmission electron microscopy (TEM), X-ray diffraction (XRD) and nitrogen adsorption analysis. H2-TPR analysis of Co/Al2O3indicated three temperature regions at 507◦C (low temperature), 650◦C (medium temperature) and 731◦C (high temperature) while characteristic peaks of Fe/ Al2O3appeared at 454◦C, 635◦C and 716◦C, respectively. Bimetallic nanocatalysts exhibited different physicochemical properties than those of the monometallic nanocatalysts. The incorporation of iron into cobalt nanocatalysts up to 50% of the total metal loaded enhanced the reducibility, increased the CO and H2chemisorbed and degree of reduction (DRT) while surface area decreased, further increase in the iron content resulted in a decrease in the crystallinity, increase in the average metal particle size and shift in the reduction towards higher temperatures.
Sol-Gel Synthesis of Highly Stable Nano Sized MgO from Magnesium Oxalate Dihydrate
Authors: Mastuli Mohd Sufri , Roshidah Rusdi , Mahat Annie Maria , Saat Norazira , Kamarulzaman Norlida
Published: July 2012

A sol-gel method was used to synthesize a highly stable form of MgO from magnesium oxalate dihydrate. The sol-gel products were characterized using simultaneous thermogravimetric analysis (STA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-Visible light spectroscopy (UV-Vis). From the XRD analysis, all the MgO samples showed a single face-centered cubic phase. FESEM micrographs showed a crystallite size ranging from 10 nm to 59 nm. The size of the MgO crystallites increased with increasing temperatures. The crystallite size of the MgO is still relatively small, that is, below 100 nm even when the precursor was calcined at a higher temperature of 950 °C and a longer time of 36 h. Such results indicated that the growth of the crystallites is slow for this route of synthesis. The morphologies of the MgO samples are varied from the all spherical of the lower temperature to the more cubic shape with less agglomeration of the higher calcined samples. The band gap energy of the MgO samples also increased with temperature.
Conductivities of Titanium Dioxide Obtained via the Sol-Gel Method
Authors: Mahat Annie Maria , Elong Kelimah , Aziz Nor Diyana Abdul , Mastuli Mohd Sufri , Kamarulzaman Norlida
Published: July 2012

Titanium dioxide powders were synthesized via a sol-gel method using titanium nitride as the precursor. The structure and morphology of the synthesized powders were investigated and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results indicate that pure single phase titanium dioxide of rutile structure had been obtained. It was also revealed that annealing temperature plays an important role in the formation of single phase titanium dioxide powders. Increasing heat treatments also modified the shape and surface morphology from chunks and rock-like morphology to a mixture of flaky aggregates. Conductivity studies using a.c. impedance technique was used. The conductivity of the sample annealed at 400 °C is 89 % higher than that annealed at 800 °C and attributed to the phase and morphology of the samples.
Characterization of LiMn0.3Co0.3Ni0.3Cr0.1O2 and LiMn0.333Co0.333Ni0.333O2 Synthesized via Sol-Gel Method: XRD, SEM and XPS Studies
Authors: Mohd Hilmi Jaafar , Roshidah Rusdi , Nor Sabirin Mohamed , Yahya Rosiyah , Kamarulzaman Norlida
Published: July 2012

One of the aspects most intensively researched in the continuing improvisation of lithium battery is the search for high capacity, high energy density and high performance cathode materials. Substitution of the electroactive elements with heteroatoms is one of the promising methods. In this study, a potential cathode material with a layered structure was successfully synthesized via a sol-gel method. As a comparison, the well-known LiMn1/3Co1/3Ni1/3O2(LiMn0.333Co0.333Ni0.333O2) was also synthesized using exactly the same method and conditions. Both materials were characterized using simultaneous thermogravimetric analysis (STA), X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The stoichiometries of the compounds were also confirmed through energy-dispersive X-ray spectroscopy (EDX) measurement. XRD results show that both compounds are single phase and impurity-free with well-ordered hexagonal layered structure characteristics of R-3m space group. Both compounds also show similar morphologies with well-formed crystals and clean surfaces as depicted by the SEM images. XPS measurement reveals that the introduction of chromium into LiMn1/3Co1/3Ni1/3O2results in a considerable change in the chemical environment as observed by significant changes in the binding energies (BE) of manganese, cobalt and nickel respectively.
Effect of Synthesis Method on the Nanostructures of Magnesium Oxide (MgO) and their Band Gap Energies
Authors: Chayed Nor Fadilah , Badar Nurhanna , Roshidah Rusdi , Kamarudin Norashikin , Kamarulzaman Norlida
Published: July 2012

Magnesium oxide (MgO) is a metal oxide which has many applications in industry and can be synthesized by many different synthesis methods. In this study, MgO was synthesized by using two different methods which were sol-gel and solid-state reaction methods. Both samples were annealed at 800 oC for 24 hours and characterized by using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The band gap energies for both samples were determined by using UV-Vis NIR Spectroscopy. The band gap values of the samples are evaluated from the data. It was found that the band gap energies of the MgO using different synthesis route were not the same.
Band Gap Energies of Magnesium Oxide Nanomaterials Synthesized by the Sol-Gel Method
Authors: Badar Nurhanna , Chayed Nor Fadilah , Roshidah Rusdi , Kamarudin Norashikin , Kamarulzaman Norlida
Published: July 2012

In this work, the band gap energies of magnesium oxide (MgO) were investigated to see if calcination time affects the band gap energies of the MgO. MgO nanomaterials have been prepared by a sol-gel method. MgO precursors produced were calcined at a temperature of 600 °C for 24 hours and 48 hours. The structural characterization of samples is achieved using X-Ray Diffraction (XRD) and the morphology as well as particle size of MgO were examined by Field Emission Scanning Electron Microscopy (FESEM). UV-Vis NIR spectroscopy was used to determine the band gap energies of the materials. From the results, the band gap energy of the MgO with a longer heating time exhibited a higher value.
TEM and SEM Analysis for Formation Mechanism of Tin Whiskers
Authors: Kuwano Noriyuki , Horikami Sadanori , Maeda Masanori , Sosiati Harini
Published: July 2012

Close observation with a transmission electron microscope (TEM) and a scanning electron microscope (SEM) was performed for the growth process of tin (Sn) whiskers on lead (Pb)-free Sn-plating. Whiskers were formed on a Sn layer plated on Cu/polyimide flexible substrate. The whisker was found to be of a single crystal and have a characteristic "Y"-shaped grain boundary structure at its root. The growth process of a curling whisker was successfully observed in a continuous way in SEM. TEM observation revealed that the curling whisker had a single crystallographic orientation irrespective with its external shape. these microstructures indicate that the rearrangement of dislocations plays an important role in the growth process of whiskers.
Effect of Detergent on the ZnO Nanorods Structures Synthesized via the Sol-Gel Method
Authors: Roshidah Rusdi , Azilah Abd Rahman , Kamarulzaman Norlida
Published: July 2012

ZnO is known as an inorganic material that has a variety of morphologies. The morphologies of the ZnO are much influenced by the synthesis route. In this work, two ZnO nanomaterials were prepared by the sol-gel route and the effect of detergent on the morphology and optical band gap of ZnO materials were investigated. The synthesized ZnO materials were characterized using Simultaneous Thermogravimetric Analyzer (STA), X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM). The UV-Vis spectrophotometer is used to determine the optical band gap. The results show that the presence of detergent affected the morphology of the ZnO from nanorods to nano-flakes. The band gap energy of the ZnO were also reduced from 3.14 ev to 2.98 eV from the nanorod to the nanoflakes.
Synthesis and Characterization of Al2O3 by Using a Combustion Synthesis Method
Authors: Jasimin Mawar Hazwani , Badar Nurhanna , Roshidah Rusdi , Kamarulzaman Norlida
Published: July 2012

Aluminium oxide is one of the metal oxides that can exist in many phases such as α, θ, η etc. All the phases obtained are affected by annealing temperature and synthesis route. In this research the Al2O3 powders were synthesized by the combustion method using triethanolamine as fuels. A pure η phase as well as a mixed α and η phases were obtained. The size and morphology of Al2O3 particles were studied using scanning electron microscopy (SEM).
Mesoporous Tin Phosphate as Anode Material for Lithium-Ion Cells
Authors: Bustam Mohammad Azmi , Hasanaly Siti Munirah , Man Zakaria
Published: July 2012

Mesoporous SnP2O7was synthesized via a surfactant templating method where an anionic surfactant, sodium dodecyl sulfate was used. X-ray diffraction (XRD) analysis indicates presence of mesostructure when the precursors were calcined at 200, 300 and 400 °C. Cyclic voltammetry tests carried out within 0-2.0 V (vs. Li/Li+) indicated that irreversible reduction of tin phosphate to form lithium phosphate phases and metallic tin occurred around 1.10 V and 0.69 V whereas the reversible alloying and de-alloying reaction involving lithium with tin occurred at 0.19 V and 0.52 V, respectively. Galvanostatic charge-discharge cycling tests carried out within 0-1.2V (vs. Li/Li+) showed that the mesoporous tin phosphate calcined at 400 °C exhibited a reversible discharge capacity of 738 mAh/g in the second cycle and upon reaching the tenth cycle, it retained a discharge capacity of 461 mAh/g. The relatively high capacity obtained for this anode was attributed to the mesoporous framework which provided larger surface area for reaction with lithium and minimized effect of volume changes experienced by the anode during repeated charging and discharging cycling.
Materials Characterization and Charge-Discharge Profile of LiNi1-XCoxO2 Cathodic Materials for Li-Ion Battery Application
Authors: Elong Kelimah , Roshidah Rusdi , Mohd Mokhtar Nurul Atikah , Azahidi Azira , Kamarulzaman Norlida
Published: July 2012

Mixed lithium nickel cobalt oxides are advantageous over LiCoO2due to decrease in cobalt content in the material. It is also better than LiNiO2which is known to be difficult to synthesize and has poor electrochemical properties. Partial substitution of nickel in lithium nickel oxide with cobalt significantly improves its electrochemical properties. In this work, a combustion method was used for synthesis of LiNi1-xCoxO2(x= 0.1 and 0.2). The starting materials used are nitrates of the metals or transition metals. The precursors obtained are used for thermal studies. The precursors of LiNi1-xCoxO2were annealed at a temperature of 700 °C for 24h. X-ray diffraction (XRD) showed that the materials are pure. A composite cathode comprising of the cathode active material, binder and graphite was fabricated. Charge-discharge profiles of the materials with a voltage range of 0.5 V - 4.5 V vs Li/Li+ were obtained in order to study their electrochemical characteristics. The materials exhibited several voltage plateaus attributed to different electrochemical reactions.
Characterisation of Lithium Aluminium Titanium Phosphate as Solid Electrolytes Synthesized by Mechanical Milling Method
Authors: Rusdi Hashlina , Azilah Abd Rahman , Subban Ri Hanum Yahaya , Mohamed N.S.
Published: July 2012

Lithium aluminium titanium phosphate (LATP) with different stoichiometric ratios according to the formula Li1+xAlxTi2-x(PO4)3 with x = 0, 0.2, 0.4, 0.5 and 0.8 are prepared by mechanical milling method. The structural and electrical properties of the prepared samples are investigated by X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and A.C Impedance Spectroscopy (IS). The XRD results showed that the sample milled for 60 hours has very low crystallinity with conductivity value of ˜10-7 S cm-1. The conductivity is enhanced by one order of magnitude upon sintering of the samples at 900 °C for 6 hours. This enhancement may be attributed to formation of improved grain homogeneity and contacts.
Synthesis and Electrochemical Behaviour of Lithium Manganese Vanadates
Authors: Kamarulzaman Norlida , Kamarudin Norashikin , Roshidah Rusdi , Elong Kelimah , Mohd Hilmi Jaafar
Published: July 2012

Lithium manganese vanadates are synthesized using the sol-gel method. The sol-gel method is a better synthesis method compared to that of the solid state reaction method and usually yields purer and more uniform sized particles. It also uses lower sintering temperatures and shorter time. This will be a savings in terms of costs of the material as heating requires a lot of electrical energy. Precursor materials acquired are subjected to thermal studies and a suitable sintering temperature is chosen in order to achieve pure, single phase compounds. As is well known it is not easy to get pure single phase final products for materials containing vanadium and manganese. From X-Ray diffraction (XRD), the results showed multi phase spinel lithium manganese vanadates. Battery fabrication is done using a composite cathode and a half cell is assembled in an argon filled glove box. Cell testing is done using a constant current charge-discharge procedure. The results show reasonable charge-discharge behaviour but the capacity is a little less than that for LiMn2O4.
Investigation of the Overlithiation of Layered LiNi0.7Co0.2Fe0.1O2 Material
Authors: Mohd Mokhtar Nurul Atikah , Azahidi Azira , Elong Kelimah , Badar Nurhanna , Roshidah Rusdi , Kamarulzaman Norlida
Published: July 2012

The purpose of this research was to investigate and compare the electrochemical characterization of new cathode materials LiNi0.7Co0.2Fe0.1O2 and Li1.1Ni0.6Co0.2Fe0.1O2. The materials were prepared using a combustion synthesis method. Composite cathodes were fabricated and assembled in a coin-type cell. The discharge profile showed plateaus at 3.7 V and 1.6 V. The overlithiated sample exhibited a 10.4% increase of discharge capacity in the first cycle of and an increase of 43.7% in the 5th cycle compared to the non-overlithiated sample.
Functional Films of Polymer-Nanocomposites by Electrospinning for Advanced Electronics, Clean Energy Conversion, and Storage
Authors: Rajan Jose , Archana Panikar Sathyaseelan , Viet Anh Le , Bao Qiao Liang , Loh Kian Ping , Muhammad Yusoff Mashitah , Kumar Gopinathan Nair M. Anil , Ramakrishna Seeram
Published: July 2012

An approach for making functional films of polymer – nanocomposites under the framework of nanotechnology is presented. In this methodology, nanowires of an inorganic functional material are dispersed in a functional polymeric medium and the resultant solution is developed into solid films by electrospinning technique. The final structure is a nanofibrous film – each nanofiber contains a percolating network of inorganic nanowires. The nanowires reduce the percolation threshold compared to those nanoparticles and maintain the flexibility and/or light weight of the polymers and nanomaterials. This methodology has been tested for a number of material architectures for electronic and energy devices.
Titanium Dioxide (TiO2) Films by Anodic Oxidation in Phosphoric Acid
Authors: Abdullah Hasan Zuhudi , Sorrell Charles Christopher
Published: July 2012

Anodic oxidation is an electrochemical method for the production of an oxide film on a metallic substrate. It involves the application of an electrical bias at relatively low currents while the substrate is immersed in an acid bath. The films can be very dense and stable, with a variety of microstructural characteristics. In the present work, films of the anatase polymorph of TiO2were formed on high-purity Ti foil (50 μm thickness) using phosphoric acid (0.3 M H3PO4). The conditions of oxidation involved the application of potentials (5 to 350 V) and current densities (5 to 60 mA.cm-2) for 10 min at room temperature. The films were characterised using a digital photography, laser Raman microspectroscopy, and field emission scanning electron microscopy. The thicknesses of the oxide films on Ti were measured using a thin film analyser based on optical spectroscopy principles. The colours, thicknesses, and microstructures of the films depended strongly on the applied voltage and current density. At bias more than 15 V, single-phase anatase was observed to form on Ti at low (5 mA.cm-2) and higher (up to 60 mA.cm-2) current density.
Effects of Ramp Rates with Short Holding Time on the Sinterability of Hydroxyapatite
Authors: Samuel Lai Kuan Lee , Tan Chou Yong , Singh Ramesh , Yap Boon Kar , Tolouei Ranna , Amiriyan Mahdi
Published: July 2012

Hydroxyapatite (HA) is by far the closest match to the human bone in terms of chemical composition. Furthermore, HA boasts excellent biocompatibility thus earning its reputation for human bone replacement. However, HA lacks desirable mechanical properties (i.e. hardness, fracture toughness, etc.). Due to the poor heat conductivity of ceramics, it is hypothesized that HA when sintered via conventional pressureless sintering, smaller ramp rates are advantageous as oppose to larger ramp rates. These advantages can be observed as improved densification along with improved mechanical properties. In the present work, the sintering profile for the HA green bodies were held at 1 minute in comparison to the usual 2 hours holding time. The applied ramp rates were 2 °C/min, 5 °C/min and 10 °C/min. Sintering temperatures were set to 1000, 1100, 1200, and 1300 °C. Sample characterization was then reviewed in the aspects of phase stability, % shrinkage, bulk and relative density, Young’s modulus, Vickers hardness, as well as fracture toughness. The results revealed that sintering with shorter holding time yielded an improvement in the mechanical properties of HA. It was observed that sintering HA with a 2 °C/min ramp rate does not result in the formation of extrageneous phases even when sintered to 1300 °C. Similarly at 2 °C/min and 1300 °C, densification was observed to be 99.05 %. In addition, Young’s modulus recorded its highest value (117.03 GPa) when sintered with a ramp rate of 2°C/min. It was also observed that sintering HA at a ramp rate of 2°C/min produced a hardness value of 5.88 GPa (improvement of 0.68 GPa when compared with 2 hours holding time).
Physicochemical Properties of Hydroxyapatite Extracted from Fish Scales
Authors: Zainon Ismail , Alwi N.M. , Abidin M.Z. , Haniza H.M.Z. , Ahmad M.S. , Ramli Anita
Published: July 2012

In this study, hydroxyapatite (HAp) was extracted from freshwater fish scales and saltwater fish scales using thermal decomposition method at various temperatures. The percentages of HAp in each species of raw fish scales were analysed using thermogravimetry analysis (TGA) whereas Fourier transform infrared (FTIR) was used to confirm the present of HA. The crystallinity of the HAp was studied using x-ray diffractometer (XRD). TGA and FTIR are found to be useful techniques to predict the composition of the HAp present in the fish scales. The results show that the composition of HAp in the fish scales was not significantly dependent on the species of the fish. The percentage of HAp in the fish scales ranged from 40 to 45 wt%. The heating temperature had an effect on the crystallinity and colour of the HAp produced. Results from FTIR and XRD confirmed that the HAp extracted from fish scales was similar to the HAp standard. However, the natural HAp produced from saltwater fish scales was more crystalline than that produced from freshwater fish scales. The HAp produced from this study is relatively cheap and more importantly they are HALAL for four billion Muslims population around the world.
Effect of Alloying Elements on the Microstructure and IMC Formation of SnAgCu Solder on Ni (P) Substrate
Authors: Shaik Osman Shazlin , Nurulakmal Mohd Sharif
Published: July 2012

When the use of lead was banned, the development of lead-free solders began to rise and was greatly explored. Presently, majority of the eutectic Pb-free solders are Sn-based and the most promising is ternary SnAgCu (SAC) solder. However, SnAgCu solder tends to become brittle in nature and excessive solder interfacial reactions. An attractive approach is by introducing alloying elements such as Ce, Fe and Zn into the SnAgCu solder, which allows for an increase of the mechanical properties and refine the solder microstructure as well as improve the wetting properties. The present work focuses on the effects of a series of elemental additions of 0.5% Ce, Fe and Zn into the basic Sn3.0Ag0.5Cu solder, in attempt to reduce the intermetallic compound (IMC) growth as well as joint reliability and reflow properties of the solder on Ni-P surface finish. The intermetallic compound Cu6Sn5, containing a small amount of dissolved Ni, was found to form preferentially on the Ni coating. This compound layer served as a barrier for direct reaction of Sn with the Ni-P coating. The P-rich Ni layer acts as a good diffusion barrier layer, which decreases the dissolution rate of the Ni-P layer hence decreases the growth of IMC thickness layer. It is also expected that with the addition of alloying elements, the wetting properties will be further enhanced.
Ionic Transport in PMMA-NaCF3SO3 Gel Polymer Electrolyte
Authors: Osman Zurina , Samin Siti Mariam , Othman Lisani , Isa Khairul Bahiyah Md.
Published: July 2012

In this work, the polymethylmethacrylate (PMMA) based gel polymer electrolyte samples have been prepared by the solution casting technique. The composition range of the salt was from 3 wt% to 35 wt%. The ionic conductivity of the samples was measured using a.c. impedance technique. The highest room temperature conductivity was obtained from the sample containing 30 wt% of NaCF3SO3 salt, i.e. 5.31 x 10-3 S cm-1. The increase in the ionic conductivity with increasing salt concentrations is due to the increase in both concentration and mobility of charge carriers. The decrease in ionic conductivity at higher salt concentrations can be explained by aggregation of the ions, leading to the formation of ion-pair, thus decreasing the number of charge carriers and hence the ionic mobility. The conductivity-temperature dependence obeys the Arrhenius rule from which the activation energy was evaluated. The ionic transference number estimated by dc polarization method revealed that the conducting species are predominantly ions.
Impedance Spectroscopy Study of LiTaO3 Powder Synthesized via Sol-Gel Method
Authors: Zainuddin Lili Widarti , Kamarulzaman Norlida
Published: July 2012

A ceramics sample of LiTaO3 was prepared using a sol-gel method. The sample is annealed at 750 °C for 48 hours. X-ray diffraction analysis indicate the formation of single phase, rhombohedral structure. An ac impedance study was used to analyse the conductivity of LiTaO3 at room temperature and at various temperatures.
Structural and Electrical Properties of Lanthanide Substituted-Bismuth Titanate Prepared by Low-Temperature Combustion Synthesis
Authors: Azlan Umar Al Amani , Sreekantan Srimala , Mohd Noor Ahmad Fauzi , Abd Razak Khairunisak , Tanaka Satoshi , Uematsu Keizo
Published: July 2012

This paper elucidates the structural and electrical properties of Bi4Ti3O12 (BIT), Bi3.25Nd0.75Ti3O12 (BNT075) and Bi3.25La0.75Ti3O12 (BLT075) compounds that were primarily prepared by a novel combustion route at temperature as low as 300°C. Single crystalline phase of bismuth-layered perovskite structure was obtained directly after combustion without calcination. X-ray diffraction and Raman spectra analysis showed the phase transition from orthorhombic to tetragonal symmetry with substituting compounds. Compared to BIT, the Curie temperature at maximum dielectric peak of BNT075 and BLT075 decreased to lower values of 434°C and 365°C, respectively. The loss tangen for corresponding substitution compounds were 5 times lower than that of BIT. Besides, BNT075 resulted in large remanent polarization (2Pr) and coercive field (Ec) values of 19µC/cm2 and 45kV/cm, respectively, while 17.6µC/cm2 and 42kV/cm for BLT075.
Structural and Electrical Characterization of Doped Zirconia Nanostructured Fibres
Authors: Lowe Adrian , Kho Siu Chu Deborah Eve , Lu Li
Published: July 2012

Pure and lithium-doped zirconia fibres have been produced using the electrospinning process. These fibres are seen to be mesoporous in nature and possess a dense outer skin that correlates with the existance of tetragonal structure. This tetragonal form exists in materials below a certain average grain size and also correlates well with capacitance retention, CV measurements and impedance response. During electrical performance, an initial irreversible solid electrolyte interface is believed to form and average grain size has a significant effect. This study suggests that in this mesoporous/skin form, electrospun zirconia fibres are promising energy storage materials.
Reactive Sputtering Growth and Characterizations of InN Thin Films on Si Substrates
Authors: Amirhoseiny Maryam , Zainuriah Hassan , Shashiong Ng , Ahmad Mohd Anas
Published: July 2012

We have studied the effects of deposition conditions on the crystal structure of InN films deposited on Si substrate. InN thin films have been deposited on Si(100) substrates by reactive radio frequency (RF) magnetron sputtering method with pure In target at room temperature. The nitrogen gas pressure, applied RF power and the distance between target and substrate were 2×10-2 Torr, 60 W and 8 cm, respectively. The effects of the Ar–N2 sputtering gas mixture on the structural properties of the films were investigated by using scanning electron microscope, energy-dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction techniques.
A Study of the Structural and Electrical Characteristics of Thermally Oxidized Al-Doped Zn3N2 Film on Glass
Authors: Low L.Y. , Abdullah Mat Johar , Al-Hardan N.H.
Published: July 2012

We report the deposition of aluminium doped zinc nitride film (Al-Zn3N2) on glass substrates by RF sputtering. Thermal oxidation of the film under different annealing temperature (500°C to 600°C) was carried out. Structural and electrical properties of the annealed films were investigated. XRD analysis showed that Al-Zn3N2film was successfully converted into Al-N zinc oxide (ANZO) at 500°C. I-V characteristics of the films were measured and the lowest estimated resistivity of the films of 4kΩ.cm can be achieved at 600°C.
Single Crystal X-Ray Structural Determination: A Powerful Technique for Natural Products Research and Drug Discovery
Authors: Fun Hoong Kun , Chantrapromma Suchada , Boonnak Nawong
Published: July 2012

Drug discovery from natural products resources have been extensively studied. The most important step in the discovery process is the identification of compounds with interesting biological activity. Single crystal X-ray structure determination is a powerful technique for natural products research and drug discovery in which the detailed three-dimensional structures that emerge can be co-related to the activities of these structures. This article shall present (i) co-crystal structures, (ii) determination of absolute configuration and (iii) the ability to distinguish between whether a natural product compound is a natural product or a natural product artifact. All these three properties are unique to the technique of single crystal X-ray structure determination.
Studies of MEH-PPV and MEH-PPV/MCMB Films and their Light Absorption in the Red Wavelength Region of the Visible Spectrum
Authors: Aziz Nor Diyana Abdul , Rusdi Roshidah , Kamarulzaman Norlida
Published: July 2012

Poly [2-methoxy, 5-(2-ethyl-hexyloxy)-p-phenylene-vinylene] (MEH-PPV) is a conjugated polymer that exhibit excellent luminescence properties in the visible spectrum. The fundamental absorption edge in the film is formed by the direct allowed transitions. In this work, free-standing films of MEH-PPV and MEH-PPV/MCMB were obtained by a solvent casting method. Mesocarbon Microbead (MCMB), a type of carbon, is added to the polymer producing composite films. The films were characterized by using the UV-Vis-NIR spectrophotometer. The film samples exhibited an absorption band in the red visible region. This is due to the electron transition between the non-localized bands. However, when MCMB is doped into the polymer matrix, the band absorption edge is red-shifted compared to that of the MEH-PPV pure film. Therefore, the optical band gaps of the composite films have decreased due to the presence of MCMB.
Effect of Anion Size on the Conductivity Behaviour of Hexanoyl Chitosan-Based Polymer Electrolytes
Authors: Winie Tan , Muhammad F.H. , Rosli N.H.A.
Published: July 2012

Films of hexanoyl chitosan containing lithium perchlorate (LiClO4) or lithium triflouromethanesulfonate (LiCF3SO3) were prepared by solution casting technique. The effect of anion size on the conductivity behaviour of hexanoyl chitosan has been investigated. The conductivity of 4.15 × 10-7S/cm and 4.07 × 10-6S/cm were achieved for the hexanoyl chitosan-LiClO4and hexanoyl chitosan-LiCF3SO3electrolyte system at 50wt.% of salt concentration, respectively. The Rice and Roth model was used to analysis quantitatively the obtained conductivity trends for the prepared electrolyte systems. The diffusion coefficients of cations and anions were calculated from the conductivity and transference number measurements. This is followed by the discussion on the diffusion coefficients of ClO4-and CF3SO3-anion.
Influence of Frequency and Temperature on the Dielectric Properties of Ni0.4Zn0.6Fe2O4-Polypropylene Composites
Authors: Tan Foo Khoon , Hassan Jumiah , Chong Yin Hong , Mokhtar Nurhidayaty , Hashim Mansor , Ibrahim Nor Azowa
Published: July 2012

Ni0.4Zn0.6Fe2O4-polypropylene (PP) composites were investigated for their dielectric property which constitutes the dielectric constant , and dielectric loss factor . Nickel zinc ferrites (NZF) were prepared via the conventional solid state method and sintered at 1250 °C for 10 hours. Ni0.4Zn0.6Fe2O4acts as filler while PP is the matrix. 5% and 25% NZF were added into the PP and blended to form NZF-PP composites. Dielectric measurements were made from room temperature to 120 °C at 20 °C intervals using the HP 4284A Precision LCR Meter at frequencies 240 Hz to 1 MHz. is almost constant and independent of frequency and temperature below 100 KHz before decreasing showing dispersion probably due to space charge or interfacial polarization. Distinct relaxation loss peaks can be seen emerging at about 100 KHz shifting towards the higher frequency with increasing temperature. Generally, increasing the content of filler improve the dielectric strength of the composite. Thus, addition of NZF enhances the dielectric properties of NZF-PP composite.
Effect of Compatibilizer on Impact Strength and Morphology of Polystyrene/Zinc Oxide Nanocomposites
Authors: Wacharawichanant Sirirat , Saetun Pranee , Lekkong Thunwawon , Supakanok Thongyai
Published: July 2012

This article investigated the effects of particle size of zinc oxide (ZnO) and polystyrene-co-maleic anhydride (SMA) compatibilizer on impact strength and morphology of polystyrene (PS)/ZnO71 (71 nm) and PS/ZnO250 (250 nm) nanocomposites. PS/ZnO nanocomposites with varying concentration of ZnO and SMA were prepared by a melt mixing technique in a twin screw extruder. It was found that the impact strength of PS nanocomposites increased up to a ZnO content of 1.0 wt%. Moreover, PS/ZnO250 nanocomposites had higher impact strength than PS/ZnO71 nanocomposites. The addition of SMA increased the impact strength of PS/ZnO nanocomposites with increasing SMA content. The result showed that SMA could improve impact strength of nanocomposites. The dispersion of ZnO particles on PS/ZnO nanocomposites was studied by scanning electron microscope (SEM). It was observed that the dispersion of ZnO particles of PS/ZnO nanocomposites without SMA was non-uniform and the agglomeration of ZnO particles in the polymer matrix increased with increasing ZnO content. The dispersion of ZnO particles of PS/ZnO nanocomposites after adding SMA was relatively good and only few aggregations exist. These observations support the results of the impact test where the PS/ZnO nanocomposites with SMA displayed higher impact strength than the PS/ZnO nanocomposites without SMA. The study showed that SMA was used as a compatibilizer to improve the dispersability and compatibility of ZnO particles in PS matrix.
Spinning and Characterization of Silica/Polypropylene Nanocomposite Fibers
Authors: Srisawat Natee , Nithitanakul Manit , Srikulkit Kawee
Published: July 2012

The preparation of nanocomposite resins by solution (toluene) mixing was conducted, aiming at disaggregating silica agglomerates down into primary nanoparticles. The obtained nanocomposite resin was spun into monofilament fibers using ThermoHaake® single screw extruder. The characterizations including morphological analyses (SEM and AFM) and crystallization profile (DSC). AFM images revealed that silica particles having nanoscale sizes were evenly distributed on the surface. The presence of silica nanoparticles resulted at higher crystallization temperature (Tc) of the nanocomposite fiber when compared to those of neat fiber. As a result, the shrinkage resistance of the nanocomposite fibers was significantly improved due to an effective reinforcement. The surface hydrophobicity of the nanocomposite fibers was found higher than neat fiber due to an increase in surface roughness arising from the presence of nanoparticles on the surface.
Preparation and Characterizations of Cassava Starch Nanocomposite Reinforced Kenaf
Authors: Zainuddin Siti Yasmine Zanariah , Ahmad Ishak , Kargarzadeh Hanieh
Published: July 2012

The aim of this research is to prepare biodegradable plastics which are made from the natural materials. In this study, solution casting technique is used to prepare the cassava starch nanocomposite reinforced kenaf. Prior to that, kenaf fibers undergo alkali and bleaching treatments in order to prepare the cellulose. Nanocellulose which used as reinforcing nanoparticle in the composites was then prepared by acid hydrolysis of obtained cellulose with 65% sulphuric acid. The preparation of cassava starch biocomposites was done using the mixture of sorbitol/glycerol (1:1) with various cellulose loading (0%, 2%, 4%, 6%, 8% and 10%). Finer size of cellulose is examined from the transmissions electron microscopy (TEM) analysis with diameter of 12±3.04 nm and length of 70-190 nm recorded. As for field emission scanning electron microscope (FESEM) analysis, good dispersion and strong interaction between starch and cellulose had been observed for the nanocomposite films. These contribute for enhancement in the mechanical performance which demonstrated improvement of all nanocomposite films compared to the neat matrix with 6 % cellulose composition showed the highest tensile stress value of 6.3 MPa.
Free Carrier Absorption Loss of Optical Phase Modulator
Authors: Abdul Razak Hanim , Haroon Hazura , Bidin Mardiana , Menon P. Susthitha , Shaari Sahbudin
Published: July 2012

The effect of the free carrier absorption loss on the split-ridge waveguide based phase modulator is analyzed at 1.3 and 1.55 µm. The electrical device performance is predicted using the 2-D semiconductor package SILVACO software under DC operation. Based on the simulation results, it is shown that there is a penalty of increased free carrier absorption as the injected electrons and holes are getting higher. Meanwhile, the loss of the device at 1.3 µm is smaller than that of 1.55 µm at an equal applied voltage.
Esterification Reaction Using Ionic Liquids (ILs) as Homogeneous Catalyst
Authors: Yaacob Zalita , Nordin Nor Asikin Mohamad , Yarmo Mohd Ambar
Published: July 2012

Ionic Liquids (ILs) based on 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI.NTf2) and ILs based on choline chloride (ChCl) under acidic condition was used as catalysts for esterification reaction between alcohol with fatty acid. Combination various acid namely sulphuric acid, perchloric acid, p-toulene sulphonic and various chloride salts such as ZnCl2, SnCl2and FeCl3with ionic liquids BM.NTf2and choline chloride gave acidic ILs. These acidic ILs were tested as catalysts for esterification reaction. Esterification of alcohol (methanol) with fatty acid (lauric acid) using BMI.NTf2ILs combination with H2SO4gave high activity (100 %) and selectivity (100 %) was observed over a period of 2 hours reaction with reaction temperature 70 °C. The ester was easily separated due to ILs form as biphasic with product after reaction where is ester accumulates as the upper phase and ILs with water that produce after reaction at below phase. These ILs were characterized using FTIR and NMR. From FTIR result no significant difference between ILs with combination ILs in acidic condition. The advantages of ILs as catalyst are “clean process” and “green chemistry” due to its behaviour such as non-volatile, no loss of solvent through evaporation and reduced environmentally impact. This ILs-catalyst system can be recycle for futher reaction.
Selective Synthesis of Glycerol Monoester with Heteropoly Acid as a New Catalyst
Authors: Wan Isahak Wan Nor Roslam , Ismail Manal , Nordin Norasikin Mohd , Adnan Nadia Farhana , Mohd Jahim Jamaliah , Salimon Jumat , Yarmo Mohd Ambar
Published: July 2012

In this work, we were study the selective synthesis of GME from oleic acid and glycerol using two types of solid heteropoly acid catalysts, namely silicotungstic acid bulk (STAB) and STA-silica sol gel (STA-SG). The performance and selectivity of STAB and STA-SG in the esterification reaction have been investigated and compared to the sulphuric acid (H2SO4) as conventional homogeneous catalyst. The catalysts were then characterized their physical and chemical properties using BET, XRD, TEM and XPS. XPS analyses were shown a significant formation of W-O-Si, W-O-W and Si-O-Si bonding in STA-SG compared to that in STAB. The main spectra of O1s (90.74 %, 531.5 eV) followed by other O1s peak (9.26 %, 532.8 eV) were due to the presence of W-O-W and W-O-Si bonds, respectively. The STA-SG catalyst was found to be the more environmentally benign solid acid catalyst for the esterification reaction between oleic acid and glycerol due to its lower toxicity in terms of the relatively lower pH value (pH 3.7) than the STAB (pH 2.8). In addition, the ease of separation for STA-SG catalyst was attributed to its insoluble state in the product phase. The esterification products were then analysed by FTIR and HPLC. Both the H2SO4 and the STAB gave high conversion of 100 % and 98 %, but at a lower selectivity of GME with 81.6% and 89.9%, respectively. On the contrary, the STA-SG enabled a conversion of 94 %, but with a significantly higher GME selectivity of 95 % rendering it the more efficient solid acid catalyst.
Bimetallic Basic Catalyst Comprising Niobium and Cesium Supported on MCM-48 for the Claisen-Schmidt Condensation
Authors: Endud Salasiah Binti , Mohd Nesfu Nadirah Zawani Binti
Published: July 2012

The Claisen–Schmidt condensations stand out to be important reaction in carbon–carbon bond formation as well as in the preparation of fine chemicals and intermediates with the presence of base catalyst such as NaOH. However, only few studies concern the synthesis and catalytic activity of mesoporous silica containing bimetallic compound as catalyst for aldol condensation of bulky aldehydes. The advantages of mesoporous systems with respect to zeolites are the improved reactant accessibility to the active sites and enhanced catalyst stability. Mesoporous silica with exceedingly high surface area (> 800 m2/g) and very high concentration of surface silanol groups fulfill most of the criteria for catalyst support. In this contribution, we report on the incorporation of Nb and Cs, alone or together, into the mesoporous silica with cubic mesostructure and the investigation of their catalytic properties in the Claisen-Schmidt condensation of acetophenone with benzaldehyde to produce chalcone, an aromatic ketone that forms the active sites for important biological compounds with antibacterial activities.
Pulsed LASER Deposition of MgO Thin Films
Authors: Kamarulzaman Norlida , Badar Nurhanna
Published: July 2012

MgO thin films were deposited by Pulsed Laser deposition using different process parameter. The characteristics were investigated via X-Ray diffraction (XRD), Scanning Electron Microscope (SEM) and Digital Holographic Microscope (DHM). It is found that the thin film surface morphology and thickness are different. It was found that the different process parameters such as chamber gas pressure, substrate temperature, LASER energy and number of pulses greatly influence the characteristics of the thin films obtained. The thin films have very low thicknesses of 97, 187 and 193 nm.
Effect of Nanosize MgO Addition on the Texture and Mechanical Strength of Bi-2212 Superconductor Compound
Authors: Hamid Nasri A. , Shamsudin Noor Fairuz
Published: July 2012

The Bi2Sr2CaCu2O8 (Bi-2212) high-temperature ceramic superconductor has the potential to be applied in power system applications due to its low thermal conductivity. However due to the material’s brittle nature and low strength, reinforcement of the Bi-2212 superconductor is necessary for such applications. Due to its high melting point and lower heat capacity, magnesium oxide (MgO) is an excellent candidate as the reinforcement material. In this study, 3% to 8% weight percentage of nanosize MgO powder was added to Bi-2212 superconductor. The Bi-2212/MgO compounds were palletized and heat treated, followed by partial melting and slow-cooling. X-ray diffraction (XRD) was used to study the phases present in the samples. Scanning electron microscopy (SEM) with energy dispersive X-ray (EDAX) analysis was performed to investigate the microstructure, and for identifying the elemental composition of the samples. Electrical resistance and critical current density (Jc) measurements were carried out using the standard four-probe dc method. The degree of texturing of the microstructure was determined using the texture coefficient calculations. In addition, the mechanical strength of the samples was studied by conducting compression test. The results show that the addition of small amount of MgO particles has improved the texture of the Bi-2212/MgO compound. The compound with 5% MgO addition shows significantly higher strength. Addition of higher than 8% of MgO has resulted in highly porous microstructure and subsequently decreasing the strength of the Bi-2212/MgO compound.
Production of Layered Hydrotalcite Using Tapai as Fuel
Authors: Othman Mohd Roslee , Anuar M.R. , Fernando W.J.N.
Published: July 2012

Lamellar hydrotalcite (HT) was synthesized in the laboratory following combustion method. Tapai fueled HT was found to exhibit more orderly packed microstructure and was more crystalline in nature than its urea fueled counterpart, particularly at higher combustion temperature. The pore structure of tapai fueled HT resembled that of bottle neck with possibility of tapered with open-end that might also be present. The crystal size of tapai fueled HT was larger than urea fueled HT but greater size reduction was experienced by the former material, suggesting that more energy might have been supplied to the sample to disintegrate the particles, since tapai has higher and cleaner carbohydrate source than urea.
Fabrication of Dye Sensitized Solar Cell Based on TiO2 Nanoparticles and Chlorophyll from Pandan Leaf as Active Layer
Authors: Yusoff Nurul Huda , Rosle Mohamad Firdaus , Buniran Surani
Published: July 2012

Dye sensitized solar cell (DSSC) is a new class of low-cost solar cell, that belongs to third generation solar cells in thin film based. It is based on a semiconductor formed between a photo-sensitized anode and an electrolyte, known as photoelectrochemical system. A lot of research has been conducted due to their interesting potential for low-cost, lightweight, disposable and having cell efficiency up to 10%. This paper reports the fabrication of dye sensitized solar cells using TiO2 nanoparticles and chlorophyll as active layer. TiO2 nanoparticles were prepared by sol-gel method while the chlorophyll was extracted from Pandanus amaryllifolius (Pandan leaf). TiO2 film was prepared on ITO coated glass using dip coating technique and then immersed overnight in the chlorophyll solution. An electrolyte solution composed of PC-LiClO4 was injected into the cell before sealed using glass that was coated with Pt as top electrode. An active area of 4.48 cm2 was fabricated by black masking the front side. The performance of the device was studied by observing the current-voltage characteristics of the device in dark at ambient temperature and under illumination of 100 mW/cm2 light. It was found that the device showed rectifier property in the dark and able to generate electrical current under light.
Quasicrystal Surfaces: Structure, Adsorption and Epitaxy
Authors: McGrath Ronan
Published: July 2012

A brief review is presented of quasicrystal surfaces and their use as templates for exotic epitaxial structures. The review is illustrated with several examples from the work of the Liverpool quasicrystal group.
Synthesis and Characterization of ZnO, CuO and CuO/ZnO Nanostructures by a Novel Sol-Gel Route under Ultrasonic Conditions
Authors: Abdul Rahman I.B. , Ayob M.T.M. , Mohamed Faizal , Othman Norinsan Kamil , Mohd Lawi R.L. , Shahidan Radiman
Published: July 2012

Great interests in metallic oxides have emerged because of the possibility to modify the properties of these materials for different applications such as catalysis or sensors. In this work, CuO, ZnO and CuO-ZnO nanoparticles were prepared by a novel sol-gel route under ultrasonic condition using triethanolamine as an emulsifying surfactant. Fine powders were obtained when the pH of the sols were increased to 13 using NaOH. Particle sizes of the produced oxide materials were in the range of 3-4 nm, 40-50 x 100-150 nm (diameter x length) and 100-200 nm for CuO, ZnO and CuO-ZnO, respectively. The molar ratio of triethanolamine to metal nitrate precursors was set at 2:3. TEM micrographs of these particles were obtained to elucidate the morphology of the nanoparticles. Experimental results show that the band gap energies (Eg) for CuO, ZnO and CuO-ZnO were found to be 2.71, 3.35 and 2.82 eV, respectively.