bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Refinement and Modification on Dry Sliding Wear Behavior of Hypereutectic Al-Si Cast Alloys
Authors: Kumar K.G. Basava
Published: April 2013

The microstructures and dry sliding wear behavior of Al-17Si cast alloys were studied after various melt treatments such as refinement and modification. Results indicate that combined refined and modified Al-17Si cast alloys have microstructures consisting of uniformly distributed primary silicon and fine eutectic AlSilicon particles through out the matrix. These alloys exhibited better wear resistance in the cast condition compared with the same alloy subjected to only refinement or modification. The improvements in properties observed in the present studies are mainly due to the structural differences between the refined, modified or both refined and modified over just cast Al-Si alloys. This paper attempts to investigate the influence of the microstructural changes in the Al-17Si cast alloys by refinement, modification and combined action of both on the dry sliding wear behavior.
A Study on Oxygen Storage Capacity of Zirconium-Cerium-Oxide Nanoparticles
Authors: Sajeevan Ajin C. , Sajith V.
Published: April 2013

One of the methods for the reduction of harmful emissions from diesel engines such as hydrocarbon, soot and NOx is the use of fuel born catalyst Cerium oxide. The oxygen storage capacity of Cerium oxide can be improved by coating it with metal such as Zirconium. Zr – Ce-O nanoparticles were synthesized by Co-precipitation method in the present work. Dynamic Light scattering, XRD pattern and UV-Visible spectroscopy were used for characterization of the prepared samples. Thermo gravimetric studies were conducted to investigate the thermal decomposition of Zr-Ce-O nanoparticles. The oxygen storage capacity of Zr-Ce-O nanoparticles was analyzed using TPR analysis.
SnO2 Thin Films Prepared by APCVD for Organic Solar Cells Application
Authors: Hatem Djedjiga , Belkaid Mohammed Said
Published: April 2013

Abstract: The amelioration of the efficiency of photovoltaic conversion in organic solar cells can be obtained by minimizing losses in reflection and absorption in the transparent electrode/active layer interface involving increased absorption efficiency in the active layer which can be achieved by the use of TCOs with special optical and electrical properties. Tin oxide SnO2 thin films have been prepared by APCVD method using the SnCl2 as a starting material. The surface morphology of the films deposited on glass substrates were investigated by scanning electron microscopy (SEM).The ellipsometry was used to determinate the refractive index for the films deposited at 480°C and the -sheet resistance was measured using the Four-Point probe. Transmittance of SnO2 films deposited on ITO was measured by UV-visible spectroscopy. SnO2 films prepared during 11 minutes present a sheet resistance of 19.57 Ωcm-2, transmittance higher than 80% and refractive index of 1.75 can be used as interfacial layer in organic solar cells application to minimize the reflectivity. The total reflectivity of SnO2/P3HT: PCBM obtained by using these films is less than 3%. SnO2 films can also be used as interfacial layers in inverted solar cells application.
Modeling of Cascade Solar Cell Ga0.5In0.5P /GaAs Using AMPS-1D
Authors: Dennai B. , Slimane Hassane Ben , Helmaoui A.
Published: April 2013

The primary objective of this modeling investigation is to optimize a multijunction cascade device under the AM1.5G spectrum. Based on previous studies, GaInP and GaAs cells between them tunnel junction GaAs, because of their energy band gaps, can be combined together to achieve high-efficiency double-junction devices. In this study, the top cell is made of Ga0.5In0.5P (1.74 eV) while the bottom cell is made of GaAs (1.42 eV). In order to avoid the losses and design constraints observed in two-terminal and four-terminal devices, the tandem cell GaInP /GaAs is designed with tunnel junction. In order to determine the optimal structure of the device, the top and bottom junctions were investigated and optimized with regard to the thicknesses. The optimum configuration of the device shows an efficiency of 36.4% under the AM1.5G spectrum and one sun, which is higher than the efficiency of an optimized single-junction Si cell under the same illumination conditions
Quantum Effects on the Performance of SOI Double-Gate Mosfet
Authors: Samia Slimani , Bouaza Djellouli
Published: April 2013

In spite of progress in silicon technology, the end of Mosfet scaling can be anticipated for the year 2015 so the introduction of high permittivity gate dielectric is the envisaged solution to reduce the current leakage that drives up power consumption. In this paper we investigate the impact of different gate length on SOI double gate MOSFET when SiO2 is replaced by ZrO2 as the gate dielectric using Nextnano Simulator. The impact of the quantum effects also observed on performance parameters of the DG-MOSFET such as on current, off current, drain induced barrier lowering, and sub-threshold. It is observed that less EOT with high permittivity reduces the tunnel current and serves to maintain high drive current.
Improving Processes on ZnO-Based Ultraviolet Photodetector
Authors: Yao Jian Qiang , Deng Hong , Li Mi , Deng Xue Ran , Qiu Wen Wen , Wei Min , Wen Guang Jun
Published: April 2013

This paper summarized the improving processes, such as, microstructure and surface modiﬁcations, appropriate dopants and nanostructural forms, to obtain sensitive, fast, and enhanced ultraviolet (UV) photoresponse in ZnO thin films. Furthermore, recent research progress in this field and some development features in future are also briefly analyzed.
Linearity Analysis of GME-TRC MOSFET Using SiO2 as a Gate Insulator at High Temperature
Authors: Malik Priyanka , Gupta R.S. , Gupta Mridula
Published: April 2013

This paper analysis the impact of temperature variation on gate material engineered trapezoidal recessed channel (GME-TRC) MOSFET and trapezoidal recessed channel (TRC) MOSFET, using ATLAS: 3D device simulator [. The study focuses on the linearity and analog performance comparison of GME-TRC and TRC MOSFETs and the impact of temperature variations on some of the key parameters like drain current, transconductance and the optimum bias point in terms of gm3 (third order derivative of Ids-Vgs) and VIP3 has been analysed.
Investigations on Nonlinear Optical 2-Aminopyridine Derivative Single Crystals
Authors: Dhanaraj P.V. , Rajesh N.P.
Published: April 2013

Nonlinear optical materials 2-aminopyridinium trifluoroacetate and bis (2-aminopyridinium) sulfate, were synthesized and single crystals were grown from aqueous solution employing the technique of controlled evaporation. The solubility and metastable zone width were found. The crystal structure was analyzed to reveal the molecular arrangements and the formation of hydrogen bonds in the crystal. High-resolution X-ray diffraction rocking curve measurements were performed to analyze the structural perfection of the grown crystals. Functional groups were identified and thermal behaviour and stability were studied. Mechanical and dielectric properties of crystals were analyzed. Optical studies reveal that both crystals have good transparency window. The nonlinear optical parameters of crystals were derived.
Vulnerability Index of Algiers Reinforced Concrete Buildings
Authors: Lazzali Farah , Farsi Mohamed N.
Published: April 2013

Reinforced Concrete (R/C) buildings experienced major damage in past earthquakes. Structural damage including column cracking, shear failure and collapse, were due to particular conditions, such as: poor member sizing and detailing, soft stories, building irregularity, bounding, bad quality of construction materials and workmanship. Various approaches and methods to assess the seismic vulnerability of buildings were established through examining a damage indicator: “vulnerability index”. In this work, a simplified vulnerability index based on design parameters describing the deficiencies of the structural system is proposed. The global index of each R/C building in the surveyed area is evaluated and normalized.
Using the Asphalt Pavement Dynamic Stiffness Modulus in Assessing Falling Weight Deflectometer Test Results
Authors: Badr Atef , Karlaftis Aristides G.
Published: April 2013

Assessing pavement quality has attracted significant interest in the literature. Despite this interest, what has been commonly overlooked in pavement research are cost and time related constraints imposed by the various most frequently employed methods. This study develops an approach for the rapid assessment of pavement structural quality that can be readily implemented in the field and can lead to limiting testing budget. Assessment is based on the Dynamic Stiffness Modulus (DSM) that has been recognized as a fairly accurate indicator of pavement quality. Results indicate that a DSM value of less than 0.80 indicates poor pavement conditions and a value higher than 1.20 indicates good pavement structural conditions. Also, the DSM shows a relatively good correlation with the asphalt pavement modulus in flexible pavements and, since the DSM can be easily produced in the field during testing, it can also be used to ascertain the amount of FWD testing required at each testing section.
Creation Sustainable Building Shell Using Smart Materials
Authors: Mehrabian Sahereh , Younesi Golzar , Rasoulzadeh Farzan
Published: April 2013

It’s been almost a decade that the idea of smart materials has attracted man’s attention. These materials are capable of responding to their surrounding environment and of adapting to it. The development pace of construction materials has also been towards multi-purpose and smart materials, which would ultimately result in manufacturing phase matters. In fact, the existence of smart structural materials and systems has played a substantial role in developing the idea of the smart control of a construction. These materials can improve designing methods and the construction of buildings. In the sustainable buildings design approach (a new approach to designing buildings which should meet a high level of environmental standards with an emphasis on the costs of their useful lifespan), such highly efficient materials are used because they are more adaptable to the environment and increase a building’s useful lifespan. In this article, some of the smart materials used for the façade are introduced and their performances will be studied. It is concluded that using such technologies requires less energy and very little amounts of chemicals and detergents which could be a step taken towards achieving sustainable architectural and environmental goals.
The Type of Roofs in Environmental Conditions with Different Shape and Suggested Suitable Materials
Authors: Younesi Golzar , Mehrabian Sahereh , Rasoulzadeh Farzan
Published: April 2013

Roofs from the fifth skin of buildings and define the character of the architecture. Their main function is sometimes to provide protection against the sun and wind, and sometimes to channel, collect and store rain water. Each climate required a different type of roof to its specific need protection of human life. The choice of one type of roof another depends fundamentally on the client brief, on the implications of the environment, on the climatic conditions and on the resources available or current technology. For a roof with certain quality characteristics there may be different technological and budgetary solutions. The roof must be conceived constructively, rationalized and adapted to the variable conditions of its environment. In this paper, we review the different types of roof, the materials used and their auxiliary elements.
Using Green Façade Base on Sustainable Materials in Temporary Buildings
Authors: Rasoulzadeh Farzan , Younesi Golzar , Mehrabian Sahereh
Published: April 2013

Architecture is organizing environment wisely also the organizing is a process and one of the most important factors in this process is materials of building. By using new materials base on scientific progress contemporary architecture has been developed and with this development some various face of human thinks have been appeared. Usual architectures are base on brick and stone that are limited by heavy materials and limited conditions and .contemporary architecture is approached to a kind of transparency in the architecture. In this paper try to use library resources and investigate some case studies of temporary building. Using plants in facade of building be examined as a applied material, and using the sustainable materials to goal of spread green area also and influence of nature in some part of construction contain public constructions. And be derrived principles of it that can serve as an important incetive in creative of green facade and using of green materials. The method of data collection is library studies.
The Role of Tool Pin Profile and Temperature on Friction Stir Welding of High Zinc Brass
Authors: Emamikhah Afshin , Abbasi Alireza , Lirabi Iraj , Feghhi Amir , Atefat Ali
Published: April 2013

In this experimental study, high zinc brass was welded by friction stir welding (FSW). A threaded cylindrical tool was used for welding the brass plates in butt configuration. Mechanical tests i.e. hardness, tensile, bending, and erichsen tests were performed for evaluating the welding strength. In addition, optical microscopy (OM) and scanning electron microscopy (SEM) were used as microstructural tests for estimating the material morphology. Furthermore, temperature as a function of time was measured during the welding. The results indicated close correlation between temperature and microhardness distribution as well as the uniformity of microstructure. Moreover, the welded sample showed acceptable mechanical strength during the applied mechanical tests due to adequate primary welding parameters and tool which led to sufficient produced temperature and material bonding.
Study of Twin Wire Arc Sprayed Zinc/Aluminum Coating on Low Carbon Steel Substrate: Application to Corrosion Protection
Authors: Djerourou S. , Lahmar H. , Bouhellal N. , Mebdoua Y.
Published: April 2013

Experimental study of twin wire arc sprayed Zn/Al coating on low carbon steel substrate has been undertaken in the present paper. The spray distances have a pronounced effect on the coating microstructure and it’s resistance against corrosion. Structural and surface morphological analyses of the Zn/Al coatings were performed using XRD, SEM, microhardness, metallographic microscope and gravimetric measurement analysis. The XRD analysis shows an effect only on the critallinity of the phases. The results obtained from SEM analysis show that the coating prepared at 100 mm present higher hardness, low porosity fraction compared to other prepared coatings. Metallographic microscopy and gravimetric measurement result reveals that the coating prepared at 100 mm present a best corrosion resistance when exposed to seawater solution. These studies have been made for a spray distance ranging from 100 to 140 mm.
Developing of Polypyrrole Coating on Rotating Steel Cylinder for Improving its Corrosion Resistance
Authors: El-Shazly Ahmed H. , Al-Turaif H.A.
Published: April 2013

This work investigates the possibility of using polypyrrole (PPy) coating for improving the corrosion resistance of rotating cylinder subjected to saline solution. Galvanostatic technique was used for layer formation under different conditions of current density, pyrrole monomer concentration, sodium tartrate concentration and solution pH. The potentiodynamic technique was used for examination of PPy coated steel in corrosive medium composed of 3.5%NaCl under different rotating speed ranging from 200 to 1000 rpm. The formed PPy layer was investigated for its corrosion resistance using 3.5% NaCl solution under different rotational speed using the potentiodynamic technique. The preliminary results showed that coating steel with polypyrrole layer under different rotational speed can improve its corrosion resistance by a factor ranging from 1.2 to 1.88 depending on the operating conditions
Characteristic of CP Potential for Concrete Pile Specimen with Hybrid CP
Authors: Jeong Jin A , Jin Chung Kuk
Published: April 2013

This study represents the result of hybrid cathodic protection (Hybrid CP) system application. Hybrid CP, which is the combination between sacrificial anode cathodic protection (SACP) system and impressed current cathodic protection (ICCP) system, can be optimum way to protect corrosion, especially in concrete columns. In this study, sections below a water line, i.e. submerged and tidal zones, were cathodically protected by means of SACP. In addition, ICCP was applied to the upper areas of water line, i.e. splash and atmospheric zones. Water level was changed to verify the effectiveness of hybrid CP system. The test factors were natural, CP, and 4-hour depolarization potential.
Experimental and Numerical Investigations of Push Bending of Copper Thin Walled Tubes
Authors: Abbasi Alireza , Emamikhah Afshin , Lirabi Iraj , Feghhi Amir , Bayat Yashar
Published: April 2013

In order to realize the successful process of forming the thin walled tubes in different industries, numerous methods have been registered by researchers. The tube push bending technique is a new process which allows forming tubes with lower bending ratio. In this study, the effects of push bending process on thickness variation and stress distribution are investigated. In addition, experimental and analytical studies have been dealt with in order to evaluate different bending radii. Results show close congruity between experiment and simulation.
Characterization of LTCC Tapes in Water Presence
Authors: Miskovic Goran , Toškov Saša , Marić Andrea , Blaž Nelu , Radosavljević Goran
Published: April 2013

A large number of research have been realized related to investigation of properties of Low Temperature Co-Fired Ceramic (LTCC) materials, such as influence of geometrical parameters, mechanical, electrical, thermal properties, etc. It is well known that ceramic is considered for a material which is impenetrable for water and because of that LTCC is desired for applications in harsh operating environments, such as water. This paper is dealing with investigation regarding the behavior of the LTCC material in water presence. In order to investigate that, an interdigital capacitor (IDC) was embedded between four, six and eight LTCC tapes, positioning IDC always in the middle of the entire structure. Investigation was conducted on two types of LTCC tapes, Heraeus AHT 01-005 and Heraeus AHT 08-047. Influence of the number of substrate layers on overall capacitance of IDC has also been analyzed. Value of capacitance obtained from software was compared with measured capacitance value of fabricated IDC and good agreement was obtained. Appearance of the fabricated structures is shown and measurement results are given.
Preparation of Pd/γ-Al2O3 Nanocatalyst and Characterization by X-Ray Diffraction and Transmission Electron Microscope
Authors: Hassan Karim. H.
Published: April 2013

In petrochemical industry, and mainly in ethylene production plants, acetylene presents in trace amount in ethylene gas and causes a serous problems owing to it is higher activity and being explosive at certain concentration limits with air, so it has to be converted to ethylene in selective hydrogenation. Three selective hydrogenation nanocatalysts Pd/γ-Al2O3 that contain 0.03 %, 0.05% and 0.07 wt % of palladium loaded on activated alumina were prepared by impregnation method. They were characterized for physical and chemical properties and structurally by X-ray diffraction, metal dispersion, and transmission electron microscope.
Estimation of Elastic Modulus of Dielectric Elastomer Materials Using Mooney-Rivlin and Ogden Models
Authors: Sahu Raj Kumar , Patra Karali
Published: April 2013

Elastomers have low elastic modulus, high specific energy density, light weight, high dielectric constant and high electrical breakdown strength. Due to these properties, elastomers are currently recognized as the future materials for actuator technology and actuators based on these materials are known as dielectric elastomer actuators (DEA). Based on Maxwell stress principle, these actuators transform electric energy directly into mechanical work. Modeling large actuation of this material depends on accurate estimation of E-modulus which varies with strain. In this work, E-modulus values at different strain are estimated based Mooney-Rivlin & Ogden Models. The model predicted values of E-modulus are compared with experimentally estimated values of E-modulus and found to be in good agreement.
Impact of the Inhomogenous Structure of Polysilicon TFT's Active Layer on the Electrostatic Potential Distribution
Authors: Tayoub Hadjira , Bensmain Asmaa , Zebentout Baya , Benamara Zineb
Published: April 2013

Recently polycrystalline silicon (pc-Si) thin film transistors (TFT’s) have emerged as the devices of choice for many applications. The TFTs made of a thin un-doped polycrystalline silicon film deposited on a glass substrate by the Low Pressure Chemical Vapor Deposition technique LPCVD have limits in the technological process to the temperature < 600°C. The benefit of pc-Si is to make devices with large grain size. Unfortunately, according to the conditions during deposition, the pc-Si layers can consist of a random superposition of grains of different sizes, where grains boundaries parallels and perpendiculars appear. In this paper, the transfer characteristics IDS-VGS are simulated by solving a set of two-dimensional (2D) drift-diffusion equations together with the usual density of states (DOS: exponential band tails and Gaussian distribution of dangling bonds) localized at the grains boundaries. The impact of thickness of the active layer on the distribution of the electrostatic potential and the effect of density of intergranular traps states on the TFT’s transfer characteristics IDS-VGS have been also investigated.
Nuclear Power Plant Fuel’s Quality Classification Using Ensemble Back Propagation Neural Networks
Authors: Kusumoputro Benyamin , Sutarya Dede , Na Li
Published: April 2013

Nuclear power plants fuel production is very crucial and highly complex processes, involving numerous variables. For the safety used in the Light Water Nuclear Reactor, the cylindrical uranium dioxide pellets as the main fuel element should shows uniform shape, uniform quality and a high density profile. Therefore, the assesment of the quality classification of these pellets is important for improving the efficiency of the production process. The quality of green pellets is conventionally monitored through a laboratory measurement of the physical pellets characteristics followed by a graphical chart classification technique. This method, however, is difficult to use and shows low accuracy and time consuming, since its lack of the ability to adress the non-linearity and the complexity of the relationship between the pellet’s quality variables and the pellett’s quality. In this paper, an intelligent technique is develop to classify the pellets quality by using a computational intelligence methods. Instead of a Single Back Propagation neural networks that ussualy used, an Ensemble Back Propagation neural networks is proposed. It is proved in the experimental results that the Ensemble Back Propagation neural networks show higher classification rate compare with that of Single Back Propagation neural networks, showing that this system could be applied effectively for classification of pellet quality in its fabrication process.
The Recent Progress of Research on Resistive Random Access Memory
Authors: Qiu Wen Wen , Deng Hong , Li Mi , Wei Min , Deng Xue Ran , Yao Jian Qiang , Wen Guang Jun , Tang Rong , Yang Jian , Wen Guang Jun
Published: April 2013

Resistive random access memory (RRAM) has attracted comprehensive attention from academia and industry as a new-type of nonvolatile memory. This memory has many advantages, such as high-speed, low power consumption, simple structure, high-density integration, etc. Therefore, it has a strong potential to replace DRAM. This paper summarizes the recent progress of the studies on RRAM. Although the achievement obtained has been summarized, there is still a long way from the real application. We also discuss the principle and related properties of RRAM and forecast the preparation trends of RRAM
Correlation between Frictional Force, Interface Temperature and Specific Wear Rate of Fibre Polymer Composites
Authors: Arhaim Y.H. , Shalwan A. , Yousif B.F.
Published: April 2013

Friction is classified as the main dominant element having an adverse influence on materials' lifespan and performance. Friction between any sliding contacts is continually accompanied by heat generation and shear force. The surface deterioration produces destruction in the component and reduced the life expectancy of the components. The shear force and/or the frictional heat areseen to be the main reasonscausing occurrence of the wear on surfaces and the wear removal during adhesion wear loading. In the current paper, a comprehensive experiments and observation were made to correlate the three main elements of tribology (friction, temperature, and weight loss) to epoxy and its composites based on glass and kenaf fibres. The tests were conducted in adhesive wear loading conditions against stainless steel counterface under dry contact conditions. SEM was performed to categorize the damage features of both composites. The results revealed that the interface temperature has more influence on the wear behaviour of both composites than the friction coefficient. Different destructive features were observed.
Performance Evaluation of TiAlN-PVD Coated Inserts for Machining Ti-6Al-4V under Different Cooling Strategies
Authors: Pervaiz Salman , Deiab Ibrahim , Darras Basil , Rashid Amir , Nicolescu Mihai
Published: April 2013

Titanium alloys are labeled as difficult to materials because of their low machinability rating. This paper presents an experimental study of machining Ti-6Al-4V under turning operation. All machining tests were conducted under dry, mist and flood cooling approaches by using a TiAlN coated carbide cutting inserts. All cutting experiments were conducted using high and low levels of cutting speeds and feed rates. The study compared surface finish of machined surface and flank wear at cutting edge under dry, mist and flood cooling approaches. Scanning electron microscopy was utilized to investigate the flank wear at cutting edge under various cooling approaches and cutting conditions. Investigation revealed that TiAlN coated carbides performed comparatively better at higher cutting speed.
Effect of Tempering on Mechanical Properties and Corrosion Rate of Medium and High Carbon Steel
Authors: Gebril Mohamed A. , Aldlemey M.S. , Kablan Abdessalam F.
Published: April 2013

The tempering process of medium and high carbon steel using quenching in water as quenching medium with different tempering temperatures has been investigated. The samples were quenched to room temperature in water. The mechanical properties and corrosion rate of the quench and tempering samples were measured. The result shows that hardness value of the medium and high carbon steel increased due to formation of martensite structure which is very strong phase but it is normally very brittle, so it is necessary to modify the mechanical properties and relieve internal stresses by heat treatment in the range 100-700°C. The experimental results revealed that mechanical properties of selective alloy were significantly changed by temper treatment. By increasing the tempering temperature, hardness and ultimate tensile strength are gradually decreased and ductility was improved. Moreover, the corrosion rate has been studied and shown within multiple phase structure corrosion rate increased more than martensite structure even its stressed structure.
Analysis of Delaminated Composite Plates
Authors: Mahieddine Ali , Ouali Mohammed
Published: April 2013

A mathematical model for plates with partially delaminated layers is presented to investigate their behavior. In this formulation account is taken of lateral strains. The principal advantage of the element is that it allows the modeling of delamination anywhere in the structure. The region without delamination is modeled to carry constant peel and shear stresses; while the region with delamination is modeled by assuming that there is no peel and shear stress transfer between the top and bottom layers. Numerical results of the present model are presented and its performance is evaluated for static problems. Laminated beams and plates are often used as primary load-carrying structures. However, the mechanical properties of composite materials may degrade severely in the presence of damage. One of the common types of damage modes in laminated composites is delamination. The presence of delamination is one of the most prevalent life-limiting failure modes in laminated composite structures. Many researchers had been studying the effect of delamination. Wee and Boay [1] developed an analytical model to predict the critical load of a delaminated composite laminated beam. Lee et al. [2] investigated the buckling behavior of the beam plate with multiple delaminations under compression. Kapania and Wolfe [3] examined the buckling behavior of a beam plate with two delaminations of equal length. Wang et al. [4] improved the analytical solution by including the coupling between the flexural and axial vibrations of the delaminated sub-laminates. Lee et al. [5] studied a composite beam with arbitrary lateral and longitudinal multiple delamination. Finite-element methods have been developed using the layerwise theory by Kim et al. [6]. Tan and Tong [7] developed a dynamic analytical model for the identification of delamination embedded in a laminated composite beam. To investigate the effects of delamination of a plate layers, a finite-element model is developed. Both displacement continuity and force equilibrium conditions are imposed between the regions with and without delamination. The accuracy of the approach is verified by comparing results with previously published data.
Morphology and Dimensions Controlled of Titania Nanotubes in Mixed Organic-Inorganic Electrolyte
Authors: Lim Yingchin , Zainal Zulkarnain , Hussein Mohd Zobir , Tan Weetee
Published: April 2013

The formation of self-organized and highly ordered Titania nanotubes was achieved by anodisation of Ti in a mixture of water-ethylene glycol electrolyte. Control over the dimensions and morphology of nanotubes was successfully established by changing the anodisation voltage, the ammonium fluoride (NH4F) concentration and the anodisation time. A threshold voltage of 5 V is required for nanotube formation. Collapsed tubes were formed by applying electrochemical etching at high fluoride concentration. This study also showed that the nanotube lengths ranging from 0.5 to 2.6 μm could be formed by controlling the voltage applied and fluoride concentration with preferred growth along the c-axis.
Effects of Different Types of Crosslinking of Epoxidized Natural Rubber in Semi-Metallic Friction Materials on Friction Performance
Authors: Almaslow A. , Ratnam Chantara Thevy , Ghazali M.J. , Talib R.J. , Azhari C.H.
Published: April 2013

Semi-metallic friction composites (SMFC) consist of epoxidised natural rubber with 50 mol % epoxidation (ENR50), alumina nanoparticle, steel wool, graphite and benzoxazine were prepared by melt mixing using Haake internal mixer at 90°C and 60 rpm rotor speed. The composites were vulcanized using different crosslinking systems, namely, sulfur and electron beam (EB) crosslinking. The samples were subjected for friction test in order to determine friction and wear properties of SMFC. The friction–wear properties of the SMFC crosslinked by electron beam irradiation and sulfur vulcanization system were compared. The friction coefficient in normal and hot condition of irradiated SMFC were higher than those of sulphur vulcanized samples at all applied doses. On the other hand the specific wear rates of irradiated samples were lower than the sulfur vulcanized samples at all applied doses. The sample crosslinked by EB irradiation at 150 kGy dose found to exhibit the best tribological property, as evident from the higher friction coefficient (about 0.461) and lower wear achieved at 150 kGy irradiation as compared to sulphur vulcanization of the SMFC.
Transport and Morphological Properties of Gel Polymer Electrolytes Containing Mg(CF3SO3)2
Authors: Zainol N.H. , Osman Zurina , Othman Lisani , Md. Isa K.B.
Published: April 2013

Magnesium-ion conducting gel polymer electrolytes (GPEs) based on PMMA with ethylene carbonate (EC) and propylene carbonate (PC) as a plasticizing solvent were prepared via the solution casting technique. Mg(CF3SO3)2 salt was used as source of magnesium ions, Mg2+. The variation of conductivity with salt concentrations, from 5 wt.% to 30 wt.% was studied. The gel polymer electrolyte with composition 20 wt.% of Mg(CF3SO3)2 exhibited the highest conductivity of 1.27 x 10-3 S cm-1 at room temperature. The conductivity-temperature dependence of gel polymer electrolyte films obeys Arrhenius behaviour with activation energy in the range of 0.18 eV to 0.26 eV. Ionic transport number was evaluated using DC polarization technique and it reveals the conducting species are predominantly ions. It is found that the ionic conductivity and transport properties of the prepared GPEs are consistent with the X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) studies.
One-Dimensional TiO2 Nanothorn-Like Structures Assisted TiO2 Template for High Absorption Hydrophilic Self-Cleaning
Authors: Achoi Mohd Faizal , Asiah Mohd Nor , Jani Nur Aimi , Rusop Mohamad , Abdullah Saifollah
Published: April 2013

One-dimensional (1D) titanium dioxide (TiO2) was synthesized using heat sol-dispersion immersion technique which is combination of four methods at lower temperature processing. The method is versatile with adjustable temperature, multi-ratio solution compositional and ability to tailor the structure into nanometer scale and small dimension of nanostructures. 1D TiO2 nanothorn-like structures assisted TiO2 template has been increased the performance of self-cleaning property with height of TiO2 nanostructures grew 17.5 nm at temperature 100oC. Further enhancing current work of coating function ability to the high performance and efficiency self-cleaning compared to present coating. The results showed a surface area for hydrophilic self-cleaning is 13.50 nm2 while the efficiency of 1D TiO2 nanostructures for self-cleaning through contact angle (CA) measurement indicated that 0.35 degrees after 2.30 minutes exposed to the water molecules droplets. The average of absorption coefficient (α) in UV region attribute 5.45 compared to another three heat immersions temperature.
The Elaboration of an Iron Aluminium Alloy and the Study of Impact of the Addition Element on its Physical and Mechanical Properties
Authors: Metidji Nadia , Bacha Nacer Eddine , Saidi Djamal , Boutarfaia Slimane
Published: April 2013

This work has been undertaken in order to determine the effect of alloying with Ni, Mo and B additions on physical and mechanical properties of FeAl alloys. The structural evolutions and morphological changes alloys were characterized by X. ray diffractometry (XRD), Scanning Electron Microscope (SEM) and an Optical Microscope. Antiphase domain sizes and morphologies are reported and correlations between such ordening phenomena, phase precipitations and mechanical properties (micro hardness at low temperature) are discussed.
Effects of Cathodic Protection and Coating on the Corrosion Rate of Carbon Steel in Stagnant and Flowing Freshwater
Authors: Ahdash Abdelsalam , Hamzah Esah , Ourdjini Ali , Shamsuri Siti Rahmah
Published: April 2013

The protection of carbon steel in freshwater media has been examined via two techniques (Impressed current cathodic and coating). This paper shows the reduction of corrosion rates under different conditions. Experimental tests were carried out for two types of steel (bared, coated) and with ICCP/without ICCP in stagnant and flowing freshwater. The results showed there was a variation in the values of potential according to the formation of the protection layer on the surface of steel plates. Furthermore, this layer showed such an excellent protection for both steels with ICCP in stagnant and flowing freshwater, where the values of potential had decreased from -840mV to -875 mV. However, the values of potential had increased from -702 mV to -630 mV for the coated steel without ICCP. On the other hand, the values of potential slightly fluctuated up to -10 mV for the bare steel without ICCP. The reason behind this increase is attributed to the formation of an oxide layer on the surface of the steel plate.
Effect of Nanoparticle Addition in Hybrid Sol-Gel Silane Coating on Corrosion Resistance of Low Carbon Steel
Authors: Balan Poovarasi , Ng Aaron , Beng Siang Chee , Singh Raman R.K. , Chan Eng Seng
Published: April 2013

Chromium pre-treatments of metal have been replaced by silane pre-treatments as more environmental friendly option. Nanoparticles can be added in the silane sol-gel network have been reported to improve corrosion resistance. In this work, the electrochemical corrosion resistance of low carbon steel coated with hybrid organic-inorganic sol-gel film filled with nanoparticles was evaluated. The sol-gel films have been synthesized from 3-glycidoxy-propyl-trimethoxy-silane (3-GPTMS) and tetra-ethyl-ortho-silicate (TEOS) precursors. These films have been impregnated with 300 ppm of silica or alumina nanoparticles. The electrochemical behavior of the coated steel was evaluated by means of electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Equivalent circuit modeling, used for quantifying the EIS measurements showed that sol-gel films containing silica nanoparticles improved the barrier properties of the silane coating. The silica nanoparticle-containing films showed highest initial pore resistance over the five days of immersion in 0.05M NaCl.
XRD Studies on Residual Stress of the Diamond Films Grown Using Hot Filament Chemical Vapour Deposition Technique on Silicon Nitride and Tungsten Carbide Substrates
Authors: Hamzah Esah , Yong Tze Mi , Fai Kevin Chee Mun
Published: April 2013

This study analyses residual stress measurement using X-Ray diffraction method on ultrafine-polycrystalline diamonds and polycrystalline diamonds films grown using Hot Filament Chemical Vapour Deposition technique (HFCVD) on silicon nitride(Si3N4) and tungsten carbide (WC) substrates in the same chamber at the same time with varied pretreatments prior to HFCVD diamond deposition. Measurements were taken perpendicular to the surface and the measured residual stress states of the diamond films are in compression. Thus, assuming isotropic properties of the film, the diamond films grown have tension residual stress parallel to the surface of the substrate. Residual stress is estimated to have the lowest stress for substrate that has undergone 5g/liter silicon carbide seeding process. Effects of residual stress to adhesion are discussed for both substrates.
Synthesis of Nanoporous Carbonated Hydroxyapatite Using Non-Ionic Pluronics Surfactant
Authors: Mohammad Nur Farahiyah , Yeoh Fei Yee , Othman Radzali
Published: April 2013

Hydroxyapatite (HA) is a bioceramics that commonly used as bone substitute materials, coating materials and scaffolds in orthopedics. It is well known for its remarkable biocompatibility with natural human tissue. However, synthetic HA is different from biological apatite whereby apatites contain carbonate ion which is about 3-8wt% of the hard tissues of human body which described as carbonated hydroxyapatite (CHA). Hence, synthetic CHA may have a better bioactivity than HA and more widely used as biomaterials. This study described the synthesis and characterization of nanoporous carbonated hydroxyapatite (CHA) by co-precipitation method through self-organization mechanism with different type of non-ionic surfactants (P123 and F127). Diammonium hydrogen phosphate, (NH4)2HPO4 and calcium nitrate tetrahydrate, Ca (NO3)2.4H2O were used as starting materials for preparing the precursor for CHA powder. The ammonium carbonate, NH4HCO3 was used as the main source for carbonate ion. Synthesized powder was characterized using XRD, FESEM, EDS and FTIR. From the XRD result, pure HA phase was obtained for all samples. FTIR analysis results obviously showed the substitution of carbonate ion into the apatite and confirm the formation of CHA. The FTIR results also demonstrated that the surfactants had been removed completely through calcination process. SEM image revealed a sphere-like particle shape of CHA was produced after the calcinations. The mesoporous CHA with pore size 2-12 nm (F127) and 2-8 nm (P123) was synthesized.
Synthesis and Development of Polymers-Infiltrated Porous Iron for Temporary Medical Implants: A Preliminary Result
Authors: Yusop Abdul Hakim , Hermawan Hendra
Published: April 2013

Iron has been viewed as a promised biodegradable metal for temporary implants but its slow degradation is considered as the main limitation. Some works have been done to improve its degradation rate including by alloying and by processing through powder metallurgy. This work presents new approach to accelerate the degradation rate of iron by infiltrating biodegradable polymer into the pores of bulk iron foam. Solution of poly(L-lactic-co-glycolic acid) or PLGA was infiltrated into the iron foam by vacuum infiltration method to form PLGA-infiltrated porous iron (PIPI). It was found that the existence of PLGA in the iron foam maintained the mechanical property as that of iron foam. Degradation test has shown that the PLGA lead the degradation in PIPI samples. This preliminary work has shown the potentiality of the incorporation of biodegradable polymers into biodegradable metals for tailoring their degradation rate.
Preparation and Characterization of Amine-Functionalised SBA-15
Authors: Cheah Wee Keat , Thung Wei Lee , Othman Radzali , Yeoh Fei Yee
Published: April 2013

Ever since the first report of ordered mesoporous silica by the Mobil group, various preparation techniques for mesoporous were extensively studied. In addition to the desirable large surface area, surface of mesoporous silica could be modified for specific catalytic and sensor applications. In this present study, SBA-15 mesoporous silica was prepared and further surface modification was done using organoalkoxysilane (aminopropyl and ethylendiaminopropyl). The resulting bare mesoporous silica, anime-functionalised and diamine-functionalised mesoporous silica were characterized using FTIR, XRD, SEM and EDS for the analysis of incorporation of amine functional groups, phase analysis, powder morphology and elemental analysis.
Effect of Sintering Temperature on the Mechanical Properties of Nanostructured Zirconia Fabricated via Colloidal Processing
Authors: Amat Noor Faeizah , Muchtar Andanastuti , Yahaya Norziha , Ghazali Mariyam Jameelah
Published: April 2013

This study aims to evaluate the effects of sintering temperature on the density and hardness of tetragonal zirconia polycrystals stabilized with 3 mol% 3Y-TZP dental ceramic type. Five cylindrical specimens were fabricated from zirconia powder of particle size 50 nm via colloidal processing. The specimens were sintered densely at the final sintering temperatures of 1000, 1100, 1200, and 1300 °C, respectively. The sintered density and hardness of the sintered specimen were then examined. The results showed that the sintered densities and hardness of the specimen increased as the temperature increased from 1000 °C to 1300 °C. Zirconia 3Y-TZP could gain near full density and reach hardness of as high as 11.30 GPa at the final sintering temperature of 1300 °C. The density and hardness of zirconia structured from 3Y-TZP can be improved by controlling the final sintering temperature.
Anodisation Time-Related Nanocrystallite Size of Porous Silicon Template Studied by Raman Spectroscopy, Photoluminescence and Fourier Transforms Infrared Spectroscopy
Authors: Asli N.A. , Rusop Mohamad , Abdullah Saifollah
Published: April 2013

Nanostructured Porous Silicon templates (NPSiT) were prepared by photo-electrochemical anodization of p-type crystalline silicon in HF electrolyte at different etching time. Five samples were prepared with etching time varied from 10 to 50 minutes at 20 mA/cm2 of current density. The effects of etching time on NPSiT were observed based on nanocrystallite size, photon energy and surface distribution. These studied was demonstrated by Raman spectroscopy, photoluminescence (PL) and Fourier transforms infrared spectroscopy (FTIR). It was found that NPSiT sample with large pore diameter, which is smaller nanocrystallites size of Si between pore. The optical properties of NPSiT were investigated by photoluminescence (PL) and PL peak broadening and shifting towards higher energy can be observed with increasing etching time. The optimum etching time with respect to PL intensity was obtained at 30 minutes, for which uniform pores and a shift of the PL maximum to a higher energy of 1.9 eV is observed.
Surface and Structural Properties of TiO2 Nanotubes Formation via Electrochemical Anodization
Authors: Jani Nur Aimi , Achoi Mohd Faizal , Mahat Mohd Muzamir , Abdullah Saifollah , Lockman Zainovia , Mohd Noor Ahmad Fauzi
Published: April 2013

An electrochemical anodization is a simple and low cost technique, to electrochemically synthesize self-organized titanium dioxide (TiO2) nanotubes (NTs) from 1M Na2SO4 electrolyte with anodization of Ti foil. The FESEM results showed that the average diameter size and length of TiO2 NTs was found between 50 to 60 nm and 2.5 μm, respectively. The surface morphology of arrays TiO2 NTs is uniformly deposited on Ti substrate. While, the cross-sectional of TiO2 NTs revealed that, the TiO2 NTs is arrays alignment and close each other deposited. From current-anodisation time analysis (I-t) indicates that TiO2 nanotubes were start formed at anodisation time 429.03 sec with current flows is 51.69 mA in electrochemical system.
Facile Synthesis of Polyaniline-Silver Composites through Interfacial Polymerization
Authors: Abdolahi Ahmad , Hamzah Esah , Ibrahim Zaharah , Hashim Shahrir
Published: April 2013

In this paper, the simple synthesis of polyaniline/silver composites through interfacial polymer method was studied. Polyaniline-silver composites were produced at room temperature by using ammonium persulphate as an oxidant agent in presence of silver nitrate (AgNO3). Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques were used to characterize the synthesized product. FESEM results showed the core shell shape of composites that the layer of polyaniline covered the silver particles. XRD results showed the high crystalline behaviour of the polyaniline/silver composites due to presence of silver. FTIR results also showed the successfully synthesis of the composite. This paper aims to study on synthesis and characterization of polyaniline-silver composites.
Influence of Temperature on the Hydration Heat of Polymer Modified Mortars
Authors: Liu Si Feng , Guo Si Jun , Wang Pei Ming
Published: April 2013

The hydration heat of polymer modified mortar were measured at 5°C、10°C、20°C and 40°C using Multi-channel Isothermal calorimeter. The effects of temperature on hydration heat of polymer modified mortars with 0.1% methyl hydroxylpropyl cellulose (MHPC), 3% ethylene vinyl acetate (EVA) and 0.1%MHPC+3%EVA were investigated. The curves of hydration heat show that the polymer reduces the hydration heat of mortars and it is related to the temperature. The effects will be more and more remarkable with the increasing of temperature; Temperature also affects the exothermic rate peak of polymer modified mortars. The exothermic rate peak of polymer modified mortar at low temperature is almost equal to that of the ordinary cement mortar. However, it is obviously lower than that of ordinary cement mortar at high temperature ; The time to the exothermic rate peak of polymer modified mortar is also related to the temperature.