bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Al2O3 Thin Films Deposited by PLD
Authors: Badar Nurhanna , Kamarulzaman Norlida
Published: February 2014

Aluminium Oxide (Al2O3) thin films have been widely used in many kinds of applications due to their excellent properties such as good mechanical strength, high abrasive and insulating characteristics. In this work, Al2O3 thin films are deposited on silicon (100) substrates using pulsed laser deposition (PLD). The deposition is done using different chamber environments. The crystal structure of the thin films is investigated using Grazing Incidence Diffraction (GID). The surface morphology and thicknesses of the thin films are studied by Field Emission Scanning Electron Microscopy (FESEM). The electrical current-voltage (I-V) characteristics of the thin films are measured using Signaton H150 Probe Station with Keithly 302 source measurement. It was found that the different process parameters greatly influenced the characteristics of the thin films obtained. FESEM images show high quality, smooth and dense films obtained using the PLD method. Generally, all films show rectifying behaviour.
Luminescence Properties of Transition Metal and Rare Earth Doped Cadmium Lead Borophosphate Glass
Authors: Eeu Tien Yew , Pang Xie Guan , Leow Ting Qiao , Zuahiri Ibrahim , Hussin Rosli
Published: February 2014

Series of rare earth doped Cadmium Lead borophosphate glass were prepared using melt quenching technique and their luminescence properties were studied. Raw materials were mixed and preheat for 30 minutes, melted for 10 minutes without annealing process. With the composition of 30CdO:20PbO:10B2O3:40P2O5 host glass, 1 mol% of Neodymium Oxide, Ferum Oxide, Titanium Oxide and Yttrium Oxide were doped as activator to study the luminescence effect using Photoluminescence (PL) and Ultraviolet-Visible (UV-Vis) spectrophotometer. By exciting the samples at different wavelength (200-900 nm), the excitation and emission profile were obtained and analyzed to study the energy transfer process. Referring to the spectrum obtained, selected samples were co-doped among each other to obtain desired luminescence properties. Energy level diagram were plotted to discuss and explain the emission transition and mechanism. UV-Visible spectroscopy results reveal the absorption wavelength of samples for targeted application as band filter. Physical properties such as chemical stability and color of the samples were recorded to correlate with PL and UV-Vis result.
Structural and Luminescence Properties of Eu3+ and Dy3+-Doped Magnesium Boro-Tellurite Ceramics
Authors: Bohari Nur Zu Ira , Hussin Rosli , Ibrahim Zuhairi , Jumali M.H. Haji , Uning Royston , Rohaizad Aliff
Published: February 2014

Boro-tellurite ceramics with the composition of 60B2O3-10TeO2-30MgO-1Eu2O3-1Dy2O3 in mol % were prepared by solid-state reaction method. The samples were characterized by x-ray diffraction (XRD), photoluminescence (PL) and FTIR spectroscopy. The XRD studies have revealed the presence of MgTe2O5 and MgB6O10.7H2O crystalline as the major and minor phases in these samples. The FTIR spectra reveal the presence of B-O vibrations of B-O-B, BO3 and BO4 bridging oxygen and Te-O stretching modes of Te2O, TeO3 and TeO4 units in the prepared ceramics. The PL peaks were assigned to the Eu3+ transitions 5D07F0 at 580 nm, 5D07F1 at 591 nm and 596 nm, 5D07F2 at 612, 618 and 621 nm, 5D07F3 at 651 nm, and 5D07F4 at 692 nm and 702 nm when excited at 394 nm.
Structural and Luminescence Study of Rare Earth and Transition Metal Ions Doped Lead Zinc Borophosphate Glasses
Authors: Pang Xie Guan , Eeu Tien Yew , Leong Pau Ming , Wan Shamsuri Wan Nurulhuda , Hussin Rosli
Published: February 2014

A series of glasses with composition of xPbO-(50-x)ZnO-yB2O3-(50-y)P2O5 with 0 x 50 mol% and 10 y 20 mol% were prepared by melt quenching technique, with 30 minutes pre-heating and 10 minutes for melting. The structural properties of prepared samples were studied using Fourier Transform-Infrared spectroscopy. The glasses were mainly based on PO2, BOP and BO3 unit. In order to obtain luminescence properties, another series of sample at composition 20PbO-30ZnO-10B2O3-40P2O5 doped with Fe2+, Ti2+, Y2+ and Nd2+ were prepared. These samples were investigated using Photoluminescence Spectroscopy with different excitation wavelength to compare results. Results showed that with the presence of rare earth and transition metal ions as activator in lead zinc borophosphate glass system give rise to luminescence of visible light.
Characteristics of Cuprous Oxide Thin Films Deposited on Glass and Polyethylene Terephthalate Substrates
Authors: Ooi Poh Kok , Ching Chin Guan , Ng Sha Shiong , Abdullah Mat Johar , Haslan Abu Hassan , Zainuriah Hassan
Published: February 2014

In this work, cuprous oxide (Cu2O) thin films grown on glass and polyethylene terephthalate (PET) substrates using reactive radio frequency magnetron sputtering system were investigated. Copper target with purity of 99.99% were used while high purity argon-oxygen gases were utilized as sputtering gases. Structural, morphological, and optical properties of the films were investigated by X-ray diffraction (XRD), atomic force microscopy and ultra-violet visible spectrophotometer. From the XRD results, only one single diffraction peak corresponding to cubic Cu2O (111) crystal structure were observed for both substrates. The surface morphologies of the samples were in a form of pillar-like. Root mean square surface roughness for Cu2O on glass and PET substrates were 3.37 nm and 3.20 nm, respectively. The films were highly transparent for wavelength above 600 nm. The Cu2O films have direct band gap values of around 2.56 eV as determined by Taucs method.
Effect of Pressing Force on the Physical Properties of CaMgTiO3 Ceramic Prepared by HEBM
Authors: Hassim Nurhashimah , Wan Shamsuri Wan Nurulhuda , Rodin Nur Liyana Amiar , Hussin Rosli , Deraman Karim , Ismail Bakar
Published: February 2014

CaMgTiO3 ceramics were synthesized by using the high energy ball-milling method (HEBM) at different pressing forces. The raw materials were ball milled for 20 hours and sintered at 1000°C. Ceramics surfaces morphologies and particle sizes were measured using SEM analysis. Archimedes’ method was adapted to obtain their densities and porosities. It was found that pressing forces influenced both morphologies and particle sizes. As pressing forces increased, the particle sizes decreased as shown in SEM observation. However, the particle sizes increased at 200 kN due to agglomerated grain growth. The densities were almost constant with increasing of pressing forces while porosities were reduced.
Effect of Two Annealing Temperatures on the Phases of Novel σ-Al1.9Zn0.1O3 Nanopowders
Authors: Jasimin Mawar Hazwani , Kamarulzaman Norlida , Badar Nurhanna , Roshidah Rusdi , Kasim Muhd Firdaus
Published: February 2014

Phase formation of materials depends on annealing temperature of materials. In this research, the substitution of Al with Zn to produce novel Al1.9Zn0.1O3 nanomaterials was done viaa combustion method. The effect of temperature on the phase formation of this material was investigated. The structural and morphological changes of these materials were investigated using X-Ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). In this study, pure, single phase σ-Al1.9Zn0.1O3 was successfully obtained annealed at 850 °C for 24 hours. For samples annealed at 1000 °C for 24 hours, a multiphase material was obtained containing α-Al1.9Zn0.1O3 and Al2ZnO4 phases. The multiphases can be detected by XRD and confirmed by SEM low angle backscattered electron (LABE) imaging. The results showed that the purity and phases formed depended on the annealing temperature.
MgO Nanostructured Materials Obtained Via the Solid-State Reaction Method
Authors: Chayed Nor Fadilah , Kamarulzaman Norlida , Badar Nurhanna , Roshidah Rusdi , Kamarudin Norashikin , Mastuli Mohd Sufri
Published: February 2014

Recently, several synthesis methods have been reported for producing magnesium oxide (MgO) nanostructures such as sol-gel, combustion, thermal evaporation, chemical precipitation, etc. This work describes a simple method to synthesize MgO nanostructures via a conventional solid-state reaction method using magnesium acetate tetrahydrate as a starting material. Magnesium acetate tetrahydrate was directly annealed at a temperature of 600 °C and 800 °C for 24 h. The X-Ray Diffraction (XRD) revealed that the annealed samples were pure while Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) showed different morphologies of MgO. From the results, it is found that TEM may reveal information that cannot be observed in the SEM micrographs.
The Influence of Yb3+ Co-Doping on Optical Properties of Sm3+-Doped Sodium Tellurite Glasses
Authors: Nawaz Fakhra , Sahar M.R. , Ghoshal Sib Krishna
Published: February 2014

A series of Sm3+-doped sodium tellurite glasses co-doped with Yb3+ were synthesized by melt quenching technique. The amorphous nature of the glasses was confirmed by X-Rays diffraction technique. From UV-Vis-NIR spectroscopy, eight absorption peaks of Sm3+ ions are observed. The broad absorption band in the range of ~870-1100 nm corresponds to the superposition of Sm3+: 6H5/2 6F11/2 and Yb3+: 2F7/2 2F5/2 transitions. The experimental and theoretical oscillator strengths of these bands were calculated by Judd-Ofelt theory. The optical band gap energy (Eopt) values for direct allowed transition and Urbach energy were found to be in the range of 2.73-2.91 eV and 0.21-0.27 eV respectively. Four luminescence emission bands 4G5/26H5/2, 6H7/2, 6H9/2 and 6H11/2 were revealed under 406 nm excitation and intensity of all bands is found to be quenched with addition of Yb3+ ions. The role of Yb3+ co-doping in the optical properties is compared and understood.
Preparation and Characterization of Soft Glass Using Sarawak Silica Sand as Starting Material for Craftware
Authors: Daud Marlinda , Abu Hassan Mahadi
Published: February 2014

Soft glass is one of the soda-lime-silicate (SLS) glass which is well-known in the craftware industry by lamp working technique . It is produced by melting the glass batch of local silica sand and certain chemicals. The SiO2 content of the silica sand is determined by wet chemical method and XRF analysis. The sand which meets the standard will be ground to the size of 150 μm and below, dry mixed with chemicals in proportions according to the formulation. Three series of soft glass containing different amount of silica sand (70-75%) and two different melting temperature were produced. The melting temperatures varied from 1450°C to 1500°C. The thermal behavior of the glass produced was investigated by differential thermal analysis. The thermal properties of the glass such as glass transition temperature, melting temperature and linear thermal expansion coefficient were studied. From the results, it was found that the melting temperature is around 600°C 750°C and this is consistent with the value theoretically. Other characterizations such as density, refractive index and Vickers micro hardness were also been carried out.
Abstrak Kaca lembut termasuk di dalam kumpulan kaca soda-kapur-silika (SLS) yang terkenal dalam industri penghasilan kaca kraf yang menggunakan teknik lampworking. Ia dihasilkan dengan meleburkan kelompok kaca pasir silika dan bahan-bahan kimia tertentu. Kandungan SiO2 bagi pasir silika tempatan ini ditentukan oleh kaedah kimia secara basah dan analisis XRF. Pasir yang menepati piawai akan dikisar sehingga ke saiz di bawah 150 μm dan dicampur dengan bahan-bahan kimia berdasarkan formulasi yang telah ditetapkan. Tiga siri kaca lembut telah dihasilkan iaitu yang mengandungi jumlah pasir silika yang berbeza (70-75%) pada dua suhu lebur yang berbeza iaitu 1450°C ke 1500°C. Kelakuan terma kaca yang dihasilkan telah diselidiki oleh analisis pembezaan terma (DTA) . Daripada ujian ini, sifat-sifat terma kaca seperti suhu peralihan kaca, suhu pelembutan dan pekali pengembangan terma linear telah dikaji. Daripada hasil kajian, didapati bahawa suhu lebur bagi kaca ini ialah pada sekitar 600°C - 750°C dan ini adalah selari dengan nilai teori. Pencirian lain seperti ketumpatan, indeks biasan dan mikrokekerasan Vickers juga telah dilakukan.
The Thermoluminescence Response of Dy Doped Calcium Borate Glass Subjected to 6MV Photon Irradiation
Authors: Tajuddin Hamiza Ahmad , Wagiran Husin , Hussin Rosli
Published: February 2014

This paper presents the thermoluminescence (TL) response and sensitivity of various dopant concentration of Dy into borate glass. Borates glass present absorption coefficient that closely to human bone and teeth. This fact makes borate as an ideal material for TL material either for medical or environmental dosimeter. Therefore, a series of glasses based on xCaO-(100-x)B2O3 system (0 x 100) % weight has been prepared by using melt quenching method. In this research, Dy doped (0.01-0.4) mol% to 30CaO-70B2O3 glass sample were studied to investigate the TL properties in terms of dose-response relationship and sensitivity. Samples were irradiated to various doses range 0.5-4.0 Gy subjected to 6 MV photon irradiation by using LINAC Primus MLC 3339. The TL intensity of various dopant concentration were studied and it was founds that the 0.3 mol% Dy has the highest TL response and has linear dose response relationship. The highest sensitivity was calculated as 58 nC.mg-1.Gy-1 for 0.3 mol% Dy concentration.
Effect of High-Energy Ball Milling on the Charge-Discharge Behaviour of LiCo0.3Ni0.7O2
Authors: Elong Kelimah , Kamarulzaman Norlida
Published: February 2014

Li-ion cathode materials in the nanodimension should show improvement in capacity retention from the normal material. This is because the electrochemical performance of the cathode material in lithium secondary batteries depends on the electrochemical redox reaction which is affected by the surface area to volume ratio of the particles. In this work, LiCo0.3Ni0.7O2 powder will be prepared via a self-propagating combustion method and the high-energy ball milling method will be used to prepare LiCo0.3Ni0.7O2 nanopowders. X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) are used to characterize the materials. The materials are observed to be phase pure. Li-ion cells are then fabricated and tested. The cells are subjected to a series of charge-discharge cycling in the voltage range of 3.0 to 4.3 V. It was found that the nanomaterial exhibit specific capacities less than that of the normal material.
Selective Detection of Dopamine in the Presence of Uric Acid Using Polymerized Phthalo Blue Film Modified Carbon Paste Electrode
Authors: Manjunathaa Jamballi G. , Deraman Mohamad , Basri Nur Hamizah , Talib I.A.
Published: February 2014

A convenient and useful method for the voltammetric determination of dopamine (DA) and uric acid (UA) based on poly (Phthalo blue) modified carbon paste electrode (PTBMCPE) is reported in this paper. The PTBMCPE exhibits excellent electro-catalytic activities for the oxidationreduction of DA and UA, as well as eliminating the interference. Factors influencing the detection processes are optimized and the kinetic parameters are calculated. The effects of pH, scan rate and concentration of dopamine on the peak current were investigated, and the results indicated that the peak current of dopamine is the highest in 0.2 M pH 7.0 Phosphate buffer solution (PBS) and the electrode reaction corresponds to a rate-controlled process. The proposed method possesses the distinct advantages of simple, appropriate for operation, good reproducibility and highly selective and sensitive.
EMI Shielding Effectiveness of Polyvinyl Chloride and Carbon Fiber Composites in Building Construction
Authors: Ruslan Mohd Shafiq , Chew Sue Ping , Sharif Mahadi , Azid A.A. , Yusof A.
Published: February 2014

Electromagnetic Interference (EMI) shielding materials commonly refers to how effective the material in limiting the passage of electromagnetic radiation into the devices. This undesired interference may cause disturbances to the performance of the any electrical systems. Thus, with effective EMI shielding materials, electromagnetic radiations are blocked with barriers made of conductive materials. In military field, the operation of certain communication equipments such as radar system can be interfered by disturbances due to the electromagnetic radiation emitted by external sources. This paper presents the investigations on non-metal materials which are Polyvinyl Chloride (PVC) and carbon fiber composite as EMI shielding materials in building construction. These shielding materials are placed in the concrete block which casted based on the standard wall building of grade 30. These customized structures are proven to reduce signal penetration significantly in the high frequency range up to 2.4 GHz.
Growth and Structural Properties of ZnO-SWCNTs Produced by Chemical Bath Deposition and Sol-Gel Methods
Authors: Omar Azimah , Huda Abdullah , Razali M.R. , Shaari S. , Taha M.R.
Published: February 2014

Two different methods were used to synthesize and fabricate zinc oxide-carbon nanotubes (ZnO-CNTs) thin films; chemical bath deposition (CBD) and sol-gel method. Single-walled carbon nanotubes (SWCNTs) were implemented in preparing the thin films. The obtained thin films were annealed in air at different temperatures levels of 200 °C, 250 °C, 300 °C and 350 °C for 30 min. Both methods successfully grew various nanostructures of ZnO-CNTs such as nanoparticles, nanobranches and nanoflakes. The synthesized nanostructures were characterized by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The crystallite sizes were calculated between 38.54 nm and 6.13 nm. FESEM cross sectional images indicated the thin film thicknesses varied from 164.9 μm to 5.84 μm. The TEM images estimated the diameters of the SWCNTs in the range of 3.38 nm to 16.14 nm. TEM images also proved the presence of ZnO entangled between SWCNTs. A combination of ZnO and SWCNTs in the thin film proposes a simple and low cost CBD method to produce various ZnO-CNTs nanostructures with appropriate thickness.
Keywords: zinc oxide; carbon nanotubes; nanostructures; thin film
ABSTRAK
Dua kaedah telah digunakan untuk mensintesiskan serta memfabrikasi filem nipis zink oksida-karbon nanotiub (ZnO-CNTs); kaedah pemendapan kubang kimia (CBD) dan sol-gel. Karbon-nanotiub berdinding satu (SWCNTs) telah digunakan dalam penyediaan filem nipis. Filem nipis yang diperolehi disepuh-lindap melalui udara pada tahap suhu yang berbeza dari 200 °C, 250 °C, 300 °C dan 350 °C selama 30 minit. Kedua-dua kaedah telah berjaya menumbuhkan pelbagai struktur nanoZnO-CNTs seperti nanozarah, nanodahan dan nanokepingan. Pencirian struktur nanoitu dilakukan menggunakan mikroskop elektron imbasan (FESEM), belauan sinar-X (XRD) dan mikroskop electron pancaran (TEM). Saiz kristal yang dikira adalah antara 38.54 nm dan 6.13 nm. Analisis bagi keratan rentas FESEM imej menunjukkan ketebalan filem yang pelbagai dari 164.9 μm sehingga 5.84 μm. Imej TEM menganggarkan diameter karbon nanotiub dalam julat 3.38 nm sehingga 16.14 nm. Imej TEM turut mengesahkan kewujudan ZnO yang melekat di antara CNTs. Kombinasi ZnO dan SWCNTs di dalam filem nipis mencadangkan penggunaan kaedah CBD yang ringkas dan berkos murah untuk menghasilkan pelbagai struktur ZnO-CNTs bersaiz nanodengan ketebalan yang sesuai. Kata-kata kunci: zink oksida; karbon nanotiub; struktur bersaiz nano; filem nipis
Implementations of PID Controller and its Transient Behaviour in Active Suspension System
Authors: Amer Noor Hafizah , Ramli Rahizar , Wan Mahadi Wan Nor Liza , Zainul Abidin Mohd Azman , Rasol Zainab
Published: February 2014

Advancement in computational technologies has accelerated the research effort in exploring the possibility of semi-active and active suspension. Computational simulations were used widely in the studies of the controller strategies. Among them are PID controllers. Studies from previous work suggested that PID controllers are capable of improving ride comfort and road holding capability. However, very little emphasis is given to examine the whole state of the vehicle suspension system resulted from this implementation. Therefore this study will examine the application of a basic PID controller to an active suspension system (ASS) to determine the requirement of active force that should be delivered in stabilizing the whole system. Two different configurations of electromagnetic suspension system (EMS) will be considered. One variable in the vehicle system will be selected to be the controlled output of PID controller and its effect to overall vehicle state will be observed. In the cases that the PID was able to stabilize the body responses, deterioration was noticed in the wheel responses. While it stabilizes the controlled output, the active force from controller was channelled into deteriorating other vehicle parameters.
Effects of Growth Temperature on the Structural Properties of Zinc Oxide Nanograins Deposited by RF Magnetron Sputtering
Authors: Ameera N. , Abu Bakar Ahmad Shuhaimi , Najwa S. , Hakim K.M. , Mazwan M. , Sobri M. , Mamat M.H. , Musa M.Z. , Rusop M.
Published: February 2014

Nanograins zinc oxide (ZnO) with c-axis preferred orientation was deposited on glass substrates by RF magnetron sputtering. It was performed with a ZnO target with 99.999% purity at RF power of 200 W. The deposition was carried out in argon and oxygen ambient at the ratio flow-rates of 10 and 5 sccm respectively, with total deposition time of 1 hour. The films were grown atgrowth temperatures were specified at RT, 100, 200, 300, 400 and 500°C. The effects of the growth temperature on the ZnO structural property was investigated by x-ray diffraction (XRD). The best ZnO crystalline quality obtained at growth temperature, TG of 300°C was further characterized by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM).
Electrical Properties of Azo-Ferrocene as Organic Diode
Authors: Jamali Siti Athirah Mohamad , Salleh Hasiah , Tagg Tei
Published: February 2014

Ferrocene is a well-known electron donor due to its chemical stability and redox behaviour. By introducing azo dye as an acceptor in the system, the characteristics of azo-ferrocene (AF) compound as a semiconductor material have been investigated. A single layer film of AF compound was deposited on an indium tin oxide (ITO) glass substrate by electrochemical method in the potential range of 0.4 V to 0.8 V. Electrical conductivity of the thin film was investigated using a four-point probe and I-V characteristic of the diode was determined via a two-point probe method. AF material showed an average electrical conductivity of 0.246 ± 0.003 Scm-1. The forward current-voltage measurement demonstrated a bias voltage in the range of 0.87 V to 10.0 V, and the backward current-voltage measurement indicated a bias voltage in the range of-0.87 V to-7.0 V. In both forward and backward voltages, the current showed a slow increase beyond the readings of 10.0 V to-7.0 V.
Effect of Time Conditions on the Growth of ZnO Nanorods via Hydrothermal Method
Authors: Nik Aziz N.A. , Isa M.I.N. , Salleh Hasiah
Published: February 2014

In this study, ZnO nanorod arrays were fabricated using a hydrothermal method on ITO glass substrate. We can find that the dimension of ZnO nanorod will changes with different growth temperature. X-ray diffraction (XRD) patterns show that the nanorods are high-quality crystals growing along [00 direction with a high consistent orientation perpendicular to the substrate and it is also revealed that nanorods have wurtzite crystal structure. The diameter of ZnO nanorods were 100300 nm depending on the time of growth process. The surface morphology of ZnO nanorods were analyse using Scanning Electron Microscope (SEM).
Study the Electrical Properties and the Efficiency of Polythiophene with Dye and Chlorophyll as Bulk Hetero-Junction Organic Solar Cell
Authors: Salleh Hasiah , Ghapur Engku Abd Engku Ali , Nik Aziz Nik Ali , Dhafina W.A. , Hamizah A. , Laily A.R.N. , Che Hassan Hazirah
Published: February 2014

The main focus in this work is to study the electrical properties and efficiency of the mixtureof organic materials that can absorb wide range of light spectrum. Polythiophene (PT) as the main active ingredient acts as a acceptor that absorb light in range 200 -350 nm, while the tris (8-hidroxyquinoline aluminum)(Alq3)and chlorophyll acts as a donor that can absorb light from 350 nm to 700 nm. The combination of PT:Alq3:Chlo is called as bulk heterojunction in organic solar cell.The thin film of the mixture was deposited by using spin coating technique. The energy gap and electrical conductivity of thin films were measured by UV-VIS and 4-point probe respectively. The efficiency of thin film solar cell was determined by 2-point probe. Result of energy band gap of PT:Alq3:Chlo thin film is about 3.72+ 0.02 eV. The electrical conductivity showed increase with the increasing of light intensity. The conductivity of PT:Alq3:Chlo thin film at ratio 3:1:2 under radiation of 100Wm-2 is about 0.250+ 0.001 Scm-1 andthe power conversion efficiency is ~7.16%.
Investigations on Fractal Nanostructure of Zinc Oxide by Small Angle Neutron Scattering (SANS)
Authors: Razali Rehana , Putra Edy. Giri  Rachman , Mohamed Abdul Aziz , Abd Majid Wan Haliza , Wan Abdullah W.A.T. , Ibrahim Z.A.
Published: February 2014

The zinc oxide nanoparticles were synthesized by solvothermal method for 18 h at150 ̊ C with presence of DEA. The molar ratio of Zn2+ solution and DEA was fixed at 1:1. The nanostructure was studied using Small Angle Neutron Scattering (SANS) in BATAN, Indonesia. From calculation, it shows that the material has surface fractal with primary particle size of 25 nm and agglomerate size of ̴ 200 nm. X-ray diffraction (XRD) was done and the the crystallite size was calculated using Scherrer equation. Field emission electron microscopy (FESEM) was done to observe the morphological structure. It shows that the sphere-like agglomerates construct of primary nanoparticles of ZnO.
The Photodegradation of Organic Compounds by ZnO Nanopowder
Authors: Tan T.K. , Khiew P.S. , Chiu W.S. , Radiman S. , Abd-Shukor Roslan , Huang N.M. , Lim Hong Ngee
Published: February 2014

The commercialized ZnO nanopowder has been employed in this study to investigate the photocatalytic degradation of two organic compounds, Methylene Blue (MB) and Phenol Red (PR) in an aqueous suspension of ZnO nanoparticles under UV light irradiation. This study has considered ZnO as the photocatalyst because it has been reported as a suitable substitute for TiO2 in certain application. For the characterization of the ZnO photocatalyst, X-ray diffraction (XRD), transmission electron microscopy (TEM), specific surface area analysis (BET), and UV-visible spectroscopy were exploited. X-ray diffractometry result for the ZnO nanoparticles exhibit normal crystalline phase features. All observed peaks can be indexed to the pure hexagonal wurtzite crystal structures, with the space group of P63mc. From the XRD pattern, no diffraction peaks from other impurities have been observed. In addition, TEM measurement shows that most of the nanoparticles are spherical and rod-like in shape and fairly monodispersed. A significant degradation of the organic compounds were observed in the presence of the catalyst without the irradiation of the UV light and the degradation increases significantly when irradiated with the UV light for a certain period of time. Besides, for the same period of irradiation, the photodegradation of the organic compounds was increased as the photocatalyst loading increases. The BET measurement for ZnO was 11.9 m2/g. The effect of some parameters such as initial concentration of organic compounds and photocatalyst loading were also determined.
Keywords: Nanostructures; Methylene blue; Phenol red; Zinc oxide; Heterogeneous photocatalyst
Effect of Heat Treatment on Ca Substitution in a Porous Y(Ba1-xCax)2Cu3O7-δ Superconductor
Authors: Norazidah Abd Wahab , Hashim Azhan , Kasim Azman , Hidayah Hassan Nurul , Hawa J.S.
Published: February 2014

The effect of heat treatment on the superconducting properties of porous Y(Ba1-xCax)2Cu3Oδ with Ca substitution x = 0.00, 0.10, 0.20, and 0.30 via a solid-state reaction method have been investigated. The superconducting parameters, zero critical temperature, Tc zero and critical current density, Jcwere measured by the standard four point probe method in the temperature range from 20 K to 300 K, while the morphology of the samples was investigated by field emission scanning electron microscopy (FESEM). In addition structural identification was also investigated. All the samples received a heat treatment at 900 °C for 5 hours, and the Jc improved from 1.410 A/cm2 to 7.013 A/cm2 for x = 0.30 at 60 K. The heat treatment process did not change the morphology, while the crystallographic structure remained orthorhombic structure. The lattice parameter cdecreased, and the volume of the unit-cell with increasing Ca substitution.The heat treatment also led to an improvement in oxygen content to nearly 7.
Effects of (La0.67Ca0.33MnO3)x (x= 0.0, 0.8, 1.0) Additions on the Structural and Superconducting Transition Temperature of YBa2Cu3O7-δ System
Authors: Fadilah B.N. , Halim Shaari Abdul , Hashim Mansor , Ain R.S.N. , Amalina H.A.N.N. , Kechik M.M. Awang
Published: February 2014

The effect addition of manganites compound on the superconducting properties of YBCO was investigated through X-Ray diffraction (XRD), resistance-temperature (R-T) measurement, AC Susceptometer, and Scanning Electron Microscope (SEM). Samples with addition of (La0.67Ca0.33MnO3)x (LCMO) (x = 0.0, 0.8, 1.0) in YBa2Cu3O7-δ (YBCO) superconductor were prepared via solid state method. Addition of LCMO in YBCO superconductor changed the properties of samples. XRD analysis showed the addition of LCMO (0.8 wt% - 1.0 wt%) formed three new peaks of LCMO. The crystal structure is orthorhombic with space group Pmmm for pure Y123 but after addition 0.8 wt% and addition 1.0 wt% of LCMO the crystal structure was changed to tetragonal and space group P4/mmm. The temperature dependent of electrical resistance showed the samples were metallic above the transition temperature even though after addition. The Tc-on superconducting transition temperature decreased from 86 K to 84 K while the Tc-offdecreased from 76 K to 70 K. Diamagnetic onset transition temperature, Tc-on(dia)decreased from 90.2 K to 89.8 K. This suppression was due to the magnetic behaviour of the LCMO addition. Morphology observation showed that the grain size and grains boundary are decreased while the porosity was increased as the addition of LCMO increases.
Fabrication and Characterization of Porous and Non-Porous Y2CaBa4Cu7Oδ Superconductor
Authors: Senawi S.A. , Azhan H. , Yusof M.S.M. , Razali W.A.W. , Norazidah Abd Wahab , Hidayah Hassan Nurul , Hawa J.S. , Ridzwan H.J.M.
Published: February 2014

These study unveils the comparative properties of Y123 and YCa2Ba4Cu7Oy in terms of their porous and non-porous structure. The materials are optimized and improved by determining the balance factor between calcium doped substance and critical temperature (Tc). Solid state reaction method was used to fabricate the ceramic materials through a series of heating and grinding. The electrical properties of superconductor via to critical temperature, Tc and critical current density, Jc was determined using Resistivity Measurement System (RMS). The structural properties and morphology of particular material was analyzed by using X-Ray Diffraction (XRD) and Scanning Electron Microscopy respectively. The orthorhombicity parameters were reduced due to substitution of Y 3+ ion by Ca2+ ion. The critical temperature for porous structure was less than non porous structure for Ca doped Y247 system. The highest critical current density (Jc) was porous YBa2Cu3Oy which is 1.79A/cm2 instead 0.48 A/cm2 for porous Y2CaBa4Cu7Oy. SEM micrograph showed the Jc is induced significantly by continuity of grain formation via grain size. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}
AC Losses in Sn-Doped Bi1.6Pb0.4Sr2(Ca1-xSnx)2Cu3Oδ Superconductors
Authors: Hashim Azhan , Halim Shaari Abdul , Nazree A. , Kasim Azman , Senawi S.A.
Published: February 2014

Measurements of complex AC susceptibility χ = χ + χ as a function of temperature have been carried out on Sn-doped Bi1.6Pb0.4Sr2(Ca1-xSnx)2Cu3Oδ superconductor samples prepared via the conventional solid state reaction method. All the samples exhibit perfect diamagnetism below 109 K. The χ (T) curves display two-step features, indicating the presence of mixed phases and therefore weakening of the grains' coupling. The amount of shielded volume in Sn-free samples is greater than that in Sn-doped samples. The intrinsic peak due to the small AC losses within the grain was not observed in the χ (T) curves for all samples. However, the coupling peak, TP, for Sn-free samples at an applied field of 1.0 Oe was observed at 89 K and shifted to a lower temperature ranging from 59 K to 64.2 K in Sn-doped samples. The amounts of hysteresis losses above the TP in all doped samples were smaller than that of the Sn-free sample. Therefore, the effect of Sn doping suppressed the inter-granular critical current, Jcm, and the presence of weak links that coupled the superconducting grains.Keywords: BSCCO, AC Losses, Sn-doped, Superconductor
Synthesis of Fe2O3/C Nanocomposite Using Microwave Assisted Calcination Method
Authors: Swardhani Anggi Puspita , Iskandar Ferry , Mikrajuddin Abdullah , Khairurrijal Khairurrijal
Published: February 2014

Fe2O3/C nanocomposites were successfully synthesized using microwave assisted calcination method. Ferric (III) chloride hexahydrate (FeCl36H2O), sodium hydroxide (NaOH), and dextrose monohydrate (C6H12O6H2O) were used as precursors. A microwave oven of 2.445 GHz with a power of 600 W for 20 minutes was employed during the syntheses. Calcination was performed in a simple furnace at 350 °C for 30 min. The molar ratio of C:Fe is the only process parameter. From Scanning Electron Microscope images, the average particle size were 199 nm and 74 nm for the samples with molar ratio of C:Fe of 1:2 and 1:1, respectively. X-ray diffractometer spectra showed that the obtained samples have γ-Fe2O3 (maghemite) crystal structure. Using the Scherrer method, the crystallite size were 61.7, 58.8, 52.5, and 48.8 nm for the samples with the molar ratios of C:Fe of 1:3, 1:2, 1:1, and 2:1, respectively. It means that the crystallite size of the nanocomposite decreases with the increase of the molar ratio of carbon to iron (C:Fe). The Brunauer-Emmett-Teller characterization showed that the surface area as high as 255.6 m2/g is achieved by of the Fe2O3/C nanocomposite with the molar ratio of C:Fe of 1:1.
Magnetic CuFe2O4 Nanoparticles for Adsorpstion of Cr(VI) from Aqueous Solution
Authors: Hariani Poedji   Loekitowati , Riyanti Fahma
Published: February 2014

CuFe2O4 nanoparticles were synthesized by co-precipitation method from the solution of CuCl2 and FeCl3 in alkaline condition. The prepared magnetic CuFe2O4 can be used to adsorb Cr (VI) ions from aqueous solution and separated from medium by magnetic technique. The characterization of CuFe2O4 with X-Ray diffraction (XRD) showed cubic units shells with diameter in the range 15-20 nm which obtained by Transmission Electron Microscope (TEM). The saturation of magnetization is around 13 emu g-1 measured with Vibrating Sample Magnetometer (VSM). Batch adsorption studies were carried out to optimize adsorption condition. Effective conditions for adsorption of Cr (VI) were found at the weight of CuFe2O4 was 1.0 g with contact time of 60 minutes and pH 3 with adsorption capacity 9.20 mg g-1.
Chelating Agent Role in Synthesizing Cerate-Zirconate Powder by a Sol-Gel Method
Authors: Osman Nafisah , Abdullah Nur Athirah , Hasan Sharizal
Published: February 2014

In this study, powders of BaCe0.54Zr0.36Y0.1O2.95 (BCZY) were synthesized by a sol-gel method assisted with three different groups of chelating agents. The chelating agents used were citric acid, tartaric acid, glycolic acid from carboxylic group, tryelthylenetetraamine (TETA) from polyamino group, nitriloaacetic acid (NTA) and ethylenediaaminetetraacetic acid (EDTA) from polyamino carboxylic group. The samples were dried at 325 °C and calcined at a series of temperatures. The solution and resulting powder properties were studied using Fourier transform Infrared (FTIR) spectroscopy. FTIR spectra showed all the samples exhibit different characteristics of absorption bands after being treated at various temperatures. Such behavior indicates that the chelation process took place before the formation of metal oxide. The chelating agent from polyamino group that consists of N-donor atoms, which is TETA showed no characteristics peak of carbonates was detected after the sample was calcined at 1100 °C. Therefore, TETA gave a significant role in reducing calcination temperature for synthesizing cerate-zirconate powder.
Magnetic Properties and Microstructures of Polyethylene Glycol (PEG)-Coated Cobalt Ferrite (CoFe2O4) Nanoparticles Synthesized by Coprecipitation Method
Authors: Suharyadi Edi , Setiadi Eko Arief , Shabrina Nanda , Kato Takeshi , Iwata Satoshi
Published: February 2014

Magnetic nanoparticles of cobalt ferrite (CoFe2O4) have been synthesized by co-precipitation method with various synthesis temperatures, concentration of NaOH and stirring duration. The results showed that nanoparticles have well crystallized structure with various grain sizes which depend on synthesis parameters. The grain size increased with increasing synthesis temperature, decreasing concentration of NaOH and decreasing stirring duration. Magnetic characterization of CoFe2O4 nanoparticles measured by Vibrating Sample Magnetometer (VSM) showed that coercive field was decrease with the decreasing of particle size. The saturation and remnant magnetization showed increasing when crystallinity increased. However, it also depends on presence of α-Fe2O3 phases and their grain size. Based on magnetic characterization analysis, sample with parameter of synthesis temperature 80°C, concentration of NaOH 5 M and stirring duration 120 minutes have been selected to be modified using polyethylene glycol (PEG)-4000. XRD and TEM analysis showed that surface modification with PEG-4000 could increase the crystallinity of nanoparticles, decrease agglomeration and control the shape to more spherical. VSM analysis showed that modification PEG-4000 could decrease the saturation magnetization which is due to the existence of α-FeO(OH) and γ-FeO(OH) phases from bonds at interface of CoFe2O4 as confirmed by XRD and Furrier Transform Infra Red (FTIR) analysis. Keywords: magnetic nanoparticles, CoFe2O4, copresipitation, PEG-4000
The Highly Active Photocatalyst of Silver Orthophosphate under Visible Light Irradiation for Phenol Oxidation
Authors: Sulaeman Uyi , Nisa Ima Rachmah , Riapanitra Anung , Iswanto Ponco , Yin Shu , Sato Tsugio
Published: February 2014

Silver orthophosphate semiconductor was synthesized by the ion-exchange method using AgNO3 and Na2HPO4.12H2O as starting materials. The molar ratio of AgNO3 and Na2HPO4.12H2O was designed as 3:1. The product was characterized using XRD, SEM and DRS. The photocatalytic activity was determined using phenol oxidation under LED lamps with various wavelengths of visible lights such as 627nm (red), 530 nm (green) and 445 nm (blue). The body-centered cubic structure of silver orthophosphate with 1-10 μm in diameter was successfully synthesized. The band gap energy of the material could be found as 2.42 eV. The excellent photocatalytic activities of silver orthophosphate for phenol oxidation could be obtained under blue light (λ= 445nm) irradiation. The photocatalytic ability of Ag3PO4 under blue light irradiation was not lost even after heat treatment at 700°C.
Preparation of Sulfated Zirconia Using Modified Sol Gel Method
Authors: Kristiani Anis , Sembiring Kiky C. , Aulia Fauzan , Laksmono Joddy Arya , Tursiloadi Silvester , Abimanyu Haznan
Published: February 2014

A series of sulfated zirconia was prepared through sol gel method in alcohol medium. Porosity of the catalyst was developed in two different methods, which were immersion of cetyltrimethyl ammonium chloride (CTAC) surfactant as templating agent and Supercritical Fluid Extraction (SFE). The physico-chemical properties of the catalysts were characterized by Thermal Gravimetric-Differential Thermal Analysis (TG-DTA), X-ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) and Barret-Joyner-Halenda (BJH) and gravimetry method for acidity measurement following by the adsorption of organic bases. The characterization results show that different method of immersing CTAC surfactant and SFE affecting physical and chemical properties, i.e. crystalinity, surface area, pore size, pore volume and acidity.
Contact Formation at Interface of LSCO|BCZY|LSCO Symmetrical Cell: Effect of LSCO to PVP Ratio
Authors: Samat Abdullah Abdul , Safri Safira Anida , Samsudin Dalina , Jaafar Wan Salwani , Osman Nafisah
Published: February 2014

Symmetrical cells of La0.6Sr0.4CoO3-δ (LSCO) cathode and BaCe0.54Zr0.36Y0.1O2.95 (BCZY) electrolyte (LSCO|BCZY|LSCO) were fabricated by manually painting the respective LSCO cathode slurries onto pellet surfaces of BCZY. The slurries were prepared with different ratios of LSCO to polyvinyl pyrrolidone, PVP as electrode binder (LSCO:PVP). The fabricated cells were denoted as S#1 (5:1/2), S#2 (5:1), S#3 (5:3/2), S#4 (5:2) and S#5 (5:5/2). The contact formation at LSCO|BCZY interface at different ratios of LSCO:PVP was examined by a scanning electron microscope (SEM). SEM images revealed that the LSCO cathode was well adhered onto BCZY electrolyte in all samples without formation of air gap/hole at the interface, except for S#4 and S#5. The elemental composition percentage and formation of air gap/hole at the interface were confirmed by electron dispersive spectroscopy (EDS). The optimum ratio in obtaining a good adhesion between LSCO cathode and BCZY electrolyte is PVP:LSCO = 1/2 – 2 : 5. The polarization resistance (Rp) for the S#1 measured by an electrochemical impedance spectroscopy (EIS) is 0.29 Ωcm2 at 700 °C.
The Effect of Paste Preparation and Annealing Temperature of ZnO Photoelectrode to Dye-Sensitized Solar Cells (DSSC) Performance
Authors: Syukron Ahmad , Wahyuono Ruri Agung , Sawitri Dyah , Risanti Doty Dewi
Published: February 2014

Dye-sensitized Solar Cells (DSSCs) have been successfully fabricated by using ZnO nanoparticles (NPs). The ZnO photoelectrode was prepared by using pastes solved in water-based and ethanol-based solvent. The ZnO NPs was synthesized by copresipitation method, prepared by reaction from Zinc Acetate with diethylene glycol (DEG). The obtained ZnO NPs has 13.93 nm particle diameter. Scanning Electron Microscopy (SEM) showed that ZnO NPs from monodisperse spherical aggregate with particle diameter of approximately 300nm. The band gap was found of 3.29eV. Variations of annealing temperature were carried out in photo-electrode fabrication. This work employs extracts from mangosteen pericarp as natural dye for fabrication of DSSCs. DSSCs were fabricated in sandwich structure with redox couple electrolyte I3-/I- and Pt-catalyst counter electrode. The best efficiency of 0.11% (Voc = 232.4 mV, Jsc = 111.6 µA/cm2, FF = 61.41 %) was obtained for DSSCs using ZnO photo-electrode prepared by ethanol-based paste and 200°C of annealing temperature.
Utilization of Natural Porphyrin Thin Films as a Photosensitizer for Photodetectors
Authors: Utari Utari , Heru Wibowo Atmanto , Purnama Budi , Abraha Kamsul
Published: February 2014

In this study, photodetectors were assembled using natural porphyrin as a sensitizer, and their energy gap properties were investigated. The natural porphyrin thin film layered devices used in the experiments were deposited by spin coating on a patterned electrode of Cu printed circuit board substrates. The photo sensitive characteristics were measured both with and without illumination by white light. The photo sensitive effect increased with the number of layers. A maximum current of 2.6 nA was obtained when the films consisted of three layers and the current increased to 7.9 nA for seven layers. To clarify the results, the dependence of the number of layers on the energy gap was evaluated. The experiment results showed that the energy gap decreased linearly with increasing number of layers. The mutual combination of the photo sensitive effect and energy gap indicated that it is possible to apply natural porphyrin as a sensitizer for photodetector applications.
Fabrication of Aluminum Doped Silica Preform Using MCVD and Solution Doping Technique: Soot Analyses and Solution Concentration Effect
Authors: Aljamimi Salah Mohammed , Yusoff Z. , Abdul-Rashid H.A. , Anuar Khairul M.S. , Muhamad Yassin S.Z. , Zulkifli M.I. , Hanif S. , Tamchek N.
Published: February 2014

This work is part of a study of solution doping in Modified Chemical Vapor Deposition (MCVD) used for silica optical fiber fabrication. This paper will concentrate on soot characterstics and the effect of different aluminum solution concentration. The effect of three different concentration of aluminum (0.3M,0.7M and 1.2M) with heat treatment are studied while the other parameters of MCVD and solution doping are fixed such as deposition temperature, SiCl4 flow, and soaking time. The porous core layer is deposited at 1800°C and the porosity of the deposited porous layer is analyzed using gas adsorption method. Refractive index profile of the doped preform is measured using preform analyzer. The aluminum distribution across the sintered glass layer is also examined by EDX.
The Influence of Mn/Ga Solution Mole Fraction on the Solid Composition and Microstructure of GaN:Mn Thin Film Deposited on Silicon Substrate by Spin Coating Technique
Authors: Sutanto Heri , Nurhasanah Iis , Istadi Istadi , Priyono Priyono
Published: February 2014

The influence of Mn/Ga solution on the characteristics of solid composition and microstructure of GaN:Mn thin film was studied. GaN:Mn thin films were deposited on Si (111) substrate by the Chemical Solution Deposition (CSD) method using the spin coating technique. Variations of the Mn/Ga mole fraction were 4%, 6%, 8%, and 10% respectively. The GaN:Mn thin films were then heated at a temperature of 900°C for 2 hours in an N2 environment with a constant flow rate of 120 sccm. Atomic composition, crystal structure, and surface morphology of GaN:Mn thin films were characterized using X-Ray Diffraction (XRD), Energy Dispersive of X-ray (EDX), and Scanning Electron Microscope (SEM). EDX results showed that the larger the Mn/Ga mole fraction solution, the higher the Mn At percentage is. The correlation of At Mn percentage and Mn/Ga solution mole fraction is represented by the formula y = 0.023x3 - 0.352x2 - 1.742x -2.81. All of the GaN:Mn thin films still have nitrogen vacancy, carbon impurity and maintain the wurtzite polycrystalline structure. Lattice parameter a, which is in the range of 3.2077Å – 3.2621Å, and lattice parameter c, which is in the range of 5.1094Å – 5.3038Å, depend on Mn atomic percentage of the film. The Root Mean Square (RMS) of GaN:Mn thin film surface roughness is in the range of 15.3nm – 29.90nm. The grain size for the 6% Mn/Ga mole fraction thin film is homogeneous.