bluuebunny/crossref_metadata_2025 huggingface dataset:
The Algorithm to Measure Crack Width with Incircle
Authors: Ge Bao Zhen , Luo Qi Jun , Ma Bin , Wei Yong Jie , Chen Bo , Jiang Sheng Zhao
Published: April 2013

Crack is a major defect of buildings. Digital image methods are often used to detect cracks. But incorrect or un-unique results may be inverted with an inappropriate algorithm. An image processing way is presented to obtain the sole width value. Meanwhile, the crack with several branches can be measured. In the processing, the crack skeleton is first calculated. Then each of the points on the skeleton is served as a center of a group of circles, one by one. The radius of the circles is increased step by step. The iterations will not stop until any point in the circle goes out of the crack. Thus the last circle in the iteration is served as an incircle of the crack. The diameter of the incircle is a crack width in a given skeleton point. The maximal and average width of the crack will be calculated after all the incircles with all the skeleton point are traversed. The experimental results show the proposed method can extract the width of cracks in a complex context.
Research on Monitoring of Moisture Content in Transformer Oil by Using Sensors
Authors: Fu Qiang , Wang Meng Jun , Su Wei , Qian Yi Hua , Lu Guo Hua
Published: April 2013

The moisture distribution in the transformer and variation mechanism of moisture in oil is analyzed in this paper, and using relative saturation and temperature as characteristic parameters, a detail scheme of on-line monitoring moisture content in transformer oil is put forward. The polyimide-based capacitive humidity sensor and temperature sensor are employed in on-line monitoring moisture content in oil. Computer is utilized to sample and analyze the data that sensors send out. The experiment on test transformer confirms that the sensors can work reliably, and reflect the moisture content in transformer oil accurately. The method that the paper proposes can realize the purpose of on-line monitoring.
A Detection Model of Customer Alive in Information Management Application
Authors: Huang Hui Hsin
Published: April 2013

In recent years, improvements in information technology have resulted in the increased availability of customer transaction data. This trend is closely linked to an ever-growing desire on the part of the marketing manager to use the firm's customer transaction databases to detect the customer is still alive or has been churn out. This research proposes a stochastic model for information managers to estimate the recency length of customers and predict the next purchase time length after the observation period end. This paper conducts exponetail distribution as interpurchase time and calculates its recency model. The results can provide managers to segment customer or make marketing strategy.
Preparation and Characterization of Folate-Decorated Chitosan Microspheres as a Sustained-Release Drugs Carrier
Authors: Xing Zhi Hua
Published: April 2013

Folic acid-chitosan (FA-CTS) and 10-hydroxycamptothecin (HCPT)-loaded folate-conjugated chitosan (FA-CTS/HCPT) microspheres were prepared by the ionic crosslinking method.The morphological characteristics of microspheres were examined using a scanning electron microscope (SEM). The average particle size and size distribution were determined by dynamic light scattering. The drug encapsulation efficiency (EE) , loading capacity (LC)and release characteristics in vitro were determined using ultraviolet spectrophotometer.The results shown that the microspheres are uniform spherical and regular with a size between 19.79 and81.40μm.Optimized preparation parameters lead to the successful preparation of hydroxycamptothecin-loaded folate-conjugated chitosan microspheres characterized with encapsulation efficiency and loading capacity up to (86.8±0.1)% and 20.6±0.3 % respectively. More then 90% of 10-hydroxycamptothecin was released from microspheres in 4 h at artificial gastric juice, 8h at artificial small intestinal fluid with a good delayed release effect.
Performance of Two Space-Time-Frequency the Coding Schemes in Frequency Selective Channel
Authors: Shao Chao , Zhang Cheng Cheng , Xu Cun Yao , Liu Yu Ming
Published: April 2013

Discussion of two classic space-time-frequency coding (STFC) scheme in frequency selective channel transmission problems is given. One utilized the data order inversion and conjugation transform, which makes the quadrature data encoder can no longer be interpreted as orthogonality of channel parameter matrix. Another has data orthogonal pre-processing, which makes each symbol spreading stream uniformly to all sub-channels. The computer simulation results illustrate the theoretical analysis of the paper.
Disjoint Network Reliability Index Algorithm in the Application of the Power Communication Network
Authors: Sun Shao Hua , Zhao Zhen Dong , Yang Lin Hui
Published: April 2013

In order to more fully and objective evaluate the reliability of the communications network, through two disjoint network reliability algorithm analysis, pointed out that the way to resolve the problem and achieve a certain degree of practical. Example to verify the correctness of algorithm, and the calculation process of the algorithm described in detail.
Research on the Technology of XML Faceted Search Based on User’s Cognitive
Authors: Yang Lin Hui , Li Xin Ye , Sun Shao Hua
Published: April 2013

In information retrieval, the user cognitive factors on the search process and results have the significant influence. First of all, the user cognitive factors are reasonably acquired and expressed, and then the technology of XML is applied to faceted recommend. Finally, according to the XML key technical characteristics that in the result shows, different cognitive styles and space ability have different display format. To effectively improve the XML retrieval efficiency and customer satisfaction, the methods not only have the certain reference value, and also have important practical significance.
Double Sideband Suppressed Carrier Performance with Optical Balanced Detection
Authors: Lang Kuo Chen , Teng Hui Kang
Published: April 2013

A double sideband suppressed carrier (DSB-SC) achieved by optical balanced detection (OBD) approach with single photo-receiver instead of two is experimentally demonstrated. The OBD not only rejects common mode noises, it also enables the interferometer operating at dark fringe to achieve quantum noise limited (QNL) phase detection.
Time-Space Characteristics Distribution of Traffic Accidents Based on Clustering Analysis
Authors: Zheng Yi , Wang Ling
Published: April 2013

This paper uses clustering analysis method to explore time-space characteristics distribution of traffic accidents, losses converted into cash, number of deaths and injuries. We select hierarchical clustering method to analyze about 458 thousands road traffic accidents in china from 2009 to 2010. And the time-space characteristics distributions include month distribution, annual average daily distribution, annual average daily time of occurrence distribution, road type distribution, road alignment distribution. The results show that traffic accidents on expressway are bound up with these characteristics.
The Application and Research of Value Engineering for International EPC Project
Authors: Wang Li Shang , Yu Tao , Zhou Jing , Dong Hong Yu , Zhu Jian Chao
Published: April 2013

Design & Build contract is the main contracting model in the international construction market which has a high standard requirement for the main contractor which encompasses analysis of the project and cost control, critical Value Engineering in Design review stage are necessary part for the whole project. This article elaborates how to do the VE during the design stage and the practice of approval process of VE is a very effective method to create benefits for the whole project.
The Research of Test System of Notebook Use Reliability
Authors: Xu Yang , Li Ming , Li Chao
Published: April 2013

Reliability activities are throughout the life cycle of products. Based on the ideas of reliability engineering and analysis of reliability testing of notebook，a new plan of reliability testing of notebook is put forward. In the plan, the testing is designed from the field experiments, and the factor of testing is recorded by certain sensors. The test platform is built from the test items and the test requirements. The test platform has the flexible structure and intelligent control function. The test work requires the management of reliability which is aimed to form the test specification.
FIR Digital Filter Design Based on Virtual Instrument
Authors: Du Yu Jian , Chen Zu Bin , Yu Teng , Yang Yang
Published: April 2013

With the information era and the advent of the digital world, digital signal processing has become extremely important in today's one of the disciplines and technical fields.Digital signal processing in seismic signal ,communications, voice, image, automatic control radar, and other fields has been widely used.In this paper,I design several kind of FIR digital filters based on virtual instrument to solve the problem that signal noise reduction.
Effect of SiO2 Particle Size on Optical Properties of TiO2-SiO2 Nanocomposite Thin Films
Authors: Kim Je Hun , Choi Hyun Goo , Zhang Ting , Kwon Chul Han , Kim Young Ho , Kang Dong Heon
Published: April 2013

TiO2-SiO2thin film system is known to be very attractive to use for photocatalytic and display applications. In this study, TiO2-SiO2nano-composite solutions were prepared by adding colloidal solutions consisted of different SiO2nano-particle sizes (7-50 nm) into TiO2powder-dispersed solutions. TiO2-SiO2thin films on glass substrates were fabricated by the dip-coating technique and their crystal structure, surface morphology and photocatalytic properties were investigated as a function of SiO2particle size. While the SiO2particle size had little influence on the crystal structure of thin films, the photocatalytic activity and anti-reflectance (anti-glare) characteristics were found to be dependent on the SiO2particle size. This result could be explained in terms of surface characteristics and the order of degradation of methylene blue under UV light irradiation.
Probabilistic Reactive Power Optimization of Distribution Network Considering Stochastic Wind Speed and Load
Authors: Chen Shu Heng , Chen Luan , Chen Yong
Published: April 2013

Based on the probabilistic loss model of distribution network and the improved hybrid particle swarm algorithm, a reactive power optimization algorithm is presented, which encompasses the effects of stochastic wind speed and load. Firstly, with the control vector dimension’s length augmented and with the probabilistic loss method built, the reactive power optimization model is presented. Secondly, with the Niche operations embedded into the original PSO, an improved hybrid PSO algorithm is presented. Lastly, the corresponding software system program is developed in VC++ language and on basis of SQL SERVER platform. While this software system being supplied into a case, the experimental data have proved that this algorithm possesses more adaptability. At the same time, compared with the RTS algorithm, the calculating process is speeded.
Solvents-Induced Structure Transitions in Copolymer Films
Authors: Zhou Ling , Liu Yong , Sun Bing Hua
Published: April 2013

Structure transitions induced by selective solvents in diblock copolymer films are investigated by density functional theory. By changing the selectivity and the packing fraction of selective solvents, the disorder-lamellar transition, the position switched lamellar phase transitions and the reentrant transitions are observed. Phase diagrams are constructed to clarify these effects. The results provide an effective way to control the transitions between the different microstructures.
Using X-Ray Diffraction and Scanning Electron Microscope to Study Zinc Oxide Nanoparticles Prepared by Wet Chemical Method
Authors: Mubarak Tahseen H. , Hassan Karim H. , Abbas Zena Mohammed Ali
Published: April 2013

The application of nanoparticles in the processes of making commercial products has increased in recent years due to their unique physical and chemical properties. Materials whose crystallites, particle sizes are smaller than 100 nm are commonly named nanocrystalline, nanostructured, nanosized materials. There are many methods used for the preparation of nanomaterials. We use is a method which is easy if compared to other methods with the chemicals required for these methods are available and cheap. Nano zinc oxide has been prepared by wet chemical method from zinc nitrate and using sodium bicarbonate as precipitation agent. The resulting nanopowders were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM).The particle size measurement using XRD Scherer’s formula calculations confirms that the crystallite size of the ZnO nanoparticles range from 41 to 67 nm and depending on calcinations temperature. SEM micrographs reveals less number of pores with smaller lump size in addition to clearly showing the micro structural homogeneity and remarkably dense mode of packing of grains of ZnO nanoparticles with minimum porosity.
Stabilization Studies of Zirconium-Cerium Oxide Nanoparticle-Diesel Suspension
Authors: Balamurugan S. , Sajith V.
Published: April 2013

One of the methods for simultaneous improvement of combustion efficiency and reduction of hydrocarbon and nitrogen oxide emissions from diesel engines is the use of catalyst in nanosized form in diesel. Agglomeration of nanoparticles in the base fluid being a serious issue, stability of the nanofluid i.e. the catalytic nanoparticles in diesel is of much concern. In the present work Zr-CeO2 nanoparticles, which acts as storage buffer leading to the reduction of the emissions, were suspended in diesel. The nanofluids were synthesized by two step method and the dosing levels of Zr-CeO2 were varied from 5 to 25 ppm. The surfactant used to improve the stability of the nanofluid was Oleic acid. The optimum concentration of surfactant in diesel fuel was determined as 0.6 percentage by volume in diesel, by the estimation of CMC value of surfactant based on surface tension measurement. The stability of synthesized nanofluids was measured using turbidity meter which shows a good stability for a dosing level of 10 ppm, with minimal settling.
Water Treatment through Chemical Transformation and Elimination of Organic Toxin Based on Mesoporous Nickel Oxide Nanocrystals
Authors: Khairy Mohamed , El Safty Sherif A.
Published: April 2013

The development of sustainable catalyst could potentially provide a long-term solution for the industrial process that required production of a large quantity of raw materials for the chemical industry from renewable resources. Hence, achieving proper designs of highly efficient, sustainable and long-term reusable catalyst is one of the environmentally crucial issues facing humanity. Here, we report the fabrication of mesoporous NiO nanocatalyst in different morphology via a simple hydrothermal method. The mesoporous NiO nanocatalysts exhibit high catalytic activity and fast removal of toxic chemical agents from aquatic life.
Characterization of Ta-Doped Titanium Dioxide Nano Particles Produced by Sol-Gel Method
Authors: Ahmad Akhlaq , Ali Liaqat , Ramzan Naveed
Published: April 2013

Titanium dioxide also known as titania is a ceramic material. It is probably the most investigated inorganic oxide in recent years because of its non toxic nature, chemical stability and its potential effectiveness for destruction of toxic organic compounds in industrial effluents. In the present study pure and Ta doped TiO2 nanosize particles were prepared by sol-gel method. Samples with doping concentrations varying from 0.50 to 1.50 at % Ta and calcinations temperatures from 300 to 900 oC were synthesized. Changes taken place in phase transformation of the samples doped with Ta and undoped TiO2 were investigated. The effect of dopant concentration, calcinations temperature and particles size on anatase to rutile phase transformation was studied in detail. The samples were analyzed by various standard analytical tools.
Analysis of C-V Characteristics of InP(p)/InSb/Al2O3/Au MIS Structures in Wide Temperature Range
Authors: Benamara M.A. , Talbi A. , Benamara Z. , Akkal B. , Sari N. Chabane , Gruzza B. , Robert C.
Published: April 2013

Superscript textThe III-V semiconductors materials and in particularly Indium Phosphide are a promising candidates for the elaboration of high speed electronic compounds. The importance of the interface study is increasing considerably in the last years to understand, the mechanism of interface formations and to control perfectly the technology of the elaborated compounds. This study presents an electrical characterization of InP(p)/InSb/Al2O3/ Au structures in the range of temperature varying from the temperature of liquid nitrogen to the temperature of 400°K. In order to give the evolution of electrical parameters of these structures with temperature, we have realized Capacitance-Voltage measurements at high frequency for different temperatures. The found results show that there is dispersion in the accumulation region as function with temperature. The quantity of positive charges in the insulator is estimated to 1.37×1012 atm/cm2 at room temperature. This value decreases slightly with increasing temperature. It varies fromSuperscript text 1.57×1012 atm/cm2 at 77°K to 1.12×1012 atm/cm2 at 400°K. The interface insulator/semiconductor of our samples presents a good electronical quality, the state density is equal to 4.1011 eV-1.cm-2 at room temperature, this one increases from 4.7×1010 eV-1.cm-2 to 7.1011 eV-1.cm-2 when temperature increases from 77°K to 400°K.
Lattice Dynamics of Protonic Conductors AZrO3 (A = Ba, Sr & Pb): A Comparative Study
Authors: Sharma Anupam Deep , Sinha M.M.
Published: April 2013

Recently, many investigations were devoted to the study of family of perovskite-type ABO3oxides. The material belongs to ABO3 perovskite oxides family like SrZrO3, BaZrO3, PbZrO3have many characteristics which are suitable for high-voltage and high-reliability capacitor applications. Many acceptor-doped perovskite-type oxides show high protonic conductivity at elevated temperatures. In addition to their reduced temperature operation relative to traditional oxide ion conductors such as Y-stabilized ZrO2, these perovskites, because of their proton transport properties, offer the possibility of application in a number of arenas including hydrogen sensors for molten metals and hydrogen pumps. In this work we are reporting the results of our theoretical investigation on the phonon properties of ABO3mainly BaZrO3, PbZrO3& SrZrO3in cubic phases. The phonon properties are calculated by using lattice dynamical simulation method based on de Launey angular force (DAF) constant model to understand the role of phonon in these systems. The phonon dispersion curves of these proton conductors in cubic phase are also drawn.
Water Splitting Reaction by Coupled Semiconductor Photocatalysts
Authors: Asl Shahab Khameneh , Unar Denis , Asl Sh. Kh.
Published: April 2013

Photocatalyst materials is a challenging topic because it can be used in an important solution to energy and environmental issues. Recently, Z schemes based catalysts have been developed for increaseing the efficiency of water splitting process. In this paper, Pt doped Zno@ TiO2photocatalyst with a 3.2 eV band gap showed high activity for water splitting into H2and O2with an apparent quantum yield of 6.8 % at near UV ranges. In this composite, two oxide couples as an electron relay system employing to increase the efficiency of hydrogen production. Moreover, highly efficient for solar hydrogen production in the presence of electron donors were developed by adding Platinum.
Compressive Strength Characteristics of Normal Strength Concrete Cured Using Colored Polythene Sheets
Authors: Kewalramani Manish A. , Gupta Rajiv
Published: April 2013

Concrete performance is severely influenced when placed in extreme environmental conditions and hence certain measures are required to control it. The present paper proposes covering the structural members with colored polythene sheets which serves dual purpose of curing. Polythene sheets do not allow appreciable loss of water by evaporation and thus they do not delay or prevent hydration besides providing optimum temperature and humidity conditions for strength development and being water conservative. In present study concrete cubes were wrapped using five different colored polythene sheets for a period of 7-days. The study incorporates prevailing environmental conditions by relating effect of curing, including conventional methods like sprinkling and ponding on compressive strength of concrete at varied atmospheric temperatures, relative humidity and influence of available solar radiation. Significant compressive strength characteristics like initial tangent modulus and strain at peak stress are also determined for cubes at a period of 7-, 28-, and 180-days. The quality assessment of concrete cubes cast was carried out using ultrasonic pulse velocity test results. The study aims at developing a knowledge base to design an extensive decision making algorithm that identifies appropriate curing method in prevailing environmental conditions.
Boundary Integral Equation Analysis of an Inhomogeneous Medium Made of Functionally Graded Materials
Authors: Ashrafi H. , Bahadori M.R. , Keshmiri H. , Shariyat M.
Published: April 2013

The present work develops direct graded boundary integral equation formulation for behavior investigation of the inhomogeneous media made of functionally graded materials. The isoparametric boundary elements, the elastostatic governing equations and a weighted residual technique are implemented with the material characteristics that vary continuously along a given dimension. The resulting algorithm is capable of solving the quasistatic problems for elastic functionally graded media with a variety of the boundary conditions and loadings. The inhomogeneous media is made of a ceramic–metal mixture, in which the material properties vary continuously according to a power law graded distribution in a given direction. Avoiding the use of internal elements in the graded boundary element formulation is one of the main objectives of this paper, which results only in numerical discretization of the boundaries of the considered media. Some examples with continuously inhomogeneous isotropic materials were provided under different boundary conditions to evaluate the proposed numerical formulation for the FGMs.
The Effect of B4C Additions on Mechanical Properties of Fe-Cu-Co Matrix Composites for Diamond Tools
Authors: Öksüz K. Emre , Şahin Yusuf , Yildirim Ebru Sahin , Kayir Yunus
Published: April 2013

The effects of boron carbide (B4C) additions on characteristic of diamond impregnated Fe-Co-Cu matrix composites have been investigated using powder metallurgy (PM) method. For this purpose, samples of Fe-(30-60)wt. % Cu–20 wt. %Co alloys and1wt. % B4C additions of its matrix were processed by cold pressing at 350 MPa, followed by sintering at 1100°C. Microstructural examination, hardness and wear tests were performed.The microstructure of Fe–Cu–Co alloys was very sensitive to the Cu content and pore closure took place with increasing the Cu content.In addition, the addition of B4C particles increased Fe–Cu-Co hardness about 44% compared to samples without B4C particles. The experimental results showed that alloy Fe–60 wt. % Cu–20 wt. %Co-1 wt. % B4C presented the best results for use in diamond cutting tools.
Infrared Spectroscopic Study of the Thermo-Oxidative Aging of Polyethylene Containing Pro-Oxidant
Authors: Kerouani Samira , Sadoun Tahar , Azzouz Noureddine
Published: April 2013

Synthetic polymers are not normally biodegradable until they are degraded into low molecular mass species that can be assimilated by microorganisms. This means that biodegradation must be preceded by an abiotic degradation that produces monomeric and oligomeric products. It has been shown that carboxylic acids, alcohols, ketones, etc... can be utilized by microorganisms as nutrients to produce cell biomass. Polyethylene is resistant to oxidation and biodegradation because of the presence of antioxidants and stabilizers. However, it can be made oxo-biodegradable by the use of prooxidant additives. The most active prooxidants are those based on transition metal particulary Fe, Co and Mn. This study is an attempt to investigate the effect of prooxidant additives on the thermo-oxidation of polyethylene. Three differentes mulch films of polyethylene, two films with prooxidant additives consisting of salt based on cobalt and iron and the third film whitout prooxidant, were subjected to thermo-oxidative degradation which was conducted in an air oven at 70°C that normally occur during composting conditions, for extended time periods. Based on Fourier transform infrared spectroscopy the chemical and structural changes induced by this exposure were followed by monitoring the changes in carbonyl index and cristallinity. The results reveal an increase in the carbonyl groups with aging time more important for the polyehylene films containing a combination of Fe and Co additives than these obtained by the films with only one transition metal additive (Co) while the LDPE without additives represents no increase in carbonyl groups. The results show also a small variation of cristallinity for the two differents polyethylene films with pro-oxidant. This indicates that the transition metal prooxidant plays an important role in the degradation of PE films and accelerates the degradation of PE.
Performance Enhancement of CNTFETs with High-Κ Dielectric
Authors: Djamil Rechem , Salima Benkara , Kheireddine Lamamra
Published: April 2013

The potential impact of high permittivity gate dielectrics on the performance of a ballistic nanoscale CNTFET is studied over a wide range of dielectric permittivities with low temperatures ranging from room temperature down to 100 K. Using the non-equilibrium Greens function (NEGF) formalism. Device characteristics such as ION/IOFF current ratio, threshold voltage, the drain induced barrier lowering (DIBL). The effects of temperature varying are also examined.
Mixture D-Optimal Desing of Electrolyte Composition in ECH of Bevel Gears
Authors: Misra Joy Prakash , Jain Pramod Kumar , Dwivedi Dheerendra Kumar , Mehta Narinder Kumar
Published: April 2013

In Electrochemical Honing (ECH), most of the metal is removed by electrolytic dissolution and therefore, the electrolyte composition plays a crucial role in the study. This paper presents the experimental investigation to find out the optimal electrolyte composition in improving surface quality of gear teeth profile during surfacing finishing of bevel gears by ECH process. In this study, mixture of sodium chloride and sodium nitrate in different ratios were used as input parameter and the percentage improvement in bearing ratio of gear teeth profile was used as response parameters while the experimental runs were designed and planned according to the Mixture D-Optimal design. Analysis of variance was carried out and optimal electrolyte composition was investigated to conduct the confirmation experiment.
Introduction of LTCC Technology in Fabrication of the Planar Microcoils for NMR Spectroscopy
Authors: Krivic Pero
Published: April 2013

Usage of planar microcoils in nuclear magnetic resonance (NMR) analysis of volume-limited chemical and biological samples has been widespread over the decades, since these microcoils obtain high sensitivity and resolution in localized units of volume. On the other hand, low-temperature co-fired ceramic (LTCC) materials exhibit highly reliable and advantageous properties in the radio frequency (RF) working area. In this work, author tries to incorporate this prosperous material technology in to design of high quality NMR microcoils, which were so far fabricated on the glass or polymer substrates. Set of few ceramic substrate microcoils is fabricated and characterized with detailed description of fabrication process in this paper.
Selective Transport of Aromatic Molecules across Ultrathin Separation Membranes of p-Sulfonato-calix[n]arenas and Cationic Polyelectrolytes
Authors: El-Hashani Ashraf , Tieke Bernd
Published: April 2013

Ultrathin separation membranes were prepared upon alternate electro-static layer-by-layer (lbl) adsorption of anionic p-sulfonatocalix-[arenes (calix8 and calix6) and cationic Polyvinylamine (PVA) polyelectrolytes on porous polyacrylonitrile/polyethylene terephthalate (PAN/PET) substrates. The permeation rates (PR) of a variety of neutral and charged aromatic compounds across calix8/PVA and calix6/PVA membranes are investigated. The solutes were aniline (An), phenol (Ph), naphthalene (Np), alkali metal salts of benzene sulfonate (BS), naphthalene 2-sulfonate (NS) and benzene disulfonate (1, 3-BDS). For the neutral compounds, a size-selective transport was found. For charged aromatic compounds, the transport was both size-and charge-selective. Size and charge-selectivity lead to a separation factor α (Ph/1, 3-BDS) of 333.
Wear Behavior of Al-20Vol. %SiCp Composites Manufactured by Dynamic Consolidation
Authors: Eskandari H. , Ghasemi H.M.
Published: April 2013

Dynamic consolidation is the route that can be used as a processing method to produce aluminum-matrix composite. This process offers several unique advantages over the static compaction methods in conventional powder metallurgy. Al-20vol.% SiCp composites were manufactured by direct explosive compaction with various explosive pad thicknesses that resulted in densities of compacts from 92% to 98.5% TD. The wear behavior of the various compacts was evaluated using a pin-on-disc wear tester. The microstructure characterization was performed using light microscopy. The dominant wear mechanisms were evaluated using scanning electron microscopy. The results showed that the sliding wear resistance increased with the increase in the density of the compact composites.
Physical and Mechanical Properties of Visible Light Cure Composites Based on Novel Organically Modified Ceramic Resins
Authors: Lizymol P.P.
Published: April 2013

Replacement of damaged tooth is necessary for proper functioning and better aesthetics. Polymeric composites based on organic resins are the most popular materials used for restoration of damaged tooth though they have many problems like polymerization shrinkage. The post gel polymerization shrinkage causes significant stresses in the surrounding tooth structure and composite tooth bonding leading to premature restoration failure. Other problems such as uncured organic monomers leaching from the dental composites into the surrounding gum tissue have been reported to cause cytotoxic effects, pulpal necrosis, requiring tooth extraction. The present paper describes the studies on visible light cure composites based on organically modified ceramic resins. Effect of different inorganic materials incorporated during resin synthesis on mechanical properties of photo cured composite was evaluated in terms of diametral tensile strength (DTS), compressive strength (CS) and surface hardness (VHN). The better properties of photocured composites based on the novel organically modified ceramic resin which are hybrid inorganic organic resins may be due to the effective bonding between the organic and inorganic parts within the resin.
Optimization of Cutting Parameters for Turning Operation of Titanium Alloy Ti-6Al-4V Material Workpiece Using the Taguchi Method
Authors: Shahebrahimi Seyyed Pedram , Dadvand Abdolrahman
Published: April 2013

One of the most important issues in turning operations is to choose suitable parameters in order to achieve a desired surface finish. The surface finish in machining operation depends on many parameters such as workpiece material, tool material, tool coating, machining parameters, etc. The purpose of this research is to focus on the analysis of optimum cutting parameters to get the lowest surface roughness in turning Titanium alloy Ti-6Al-4V with the insert with the standard code DNMG 110404 under dry cutting condition, by the Taguchi method. The turning parameters are evaluated as cutting speed of 14, 20 and 28 m/min, feed rate of 0.12, 0.14 and 0.16 mm/rev, depth of cut of 0.3, 0.6 and 1 mm, each at three levels. The Experiment was designed using the Taguchi method and 9 experiments were conducted by this process. The results are analyzed using analysis of variance method (ANOVA). The results of analysis show that the depth of cut has a significant role to play in producing lower surface roughness that is about 63.33% followed by feed rate about 30.25%, and cutting speed has less contribution on the surface roughness. Also it was realized that with the use of the confirmation test, the surface roughness improved by 227% from its initial state.
Preparation of SnO2 Powders by Modified Polyol Synthesis Using 1,2-Propanediol and Calcination
Authors: Chee Sang Soo , Lee Jong Hyun
Published: April 2013

SnO2 powders were prepared using a modified polyol synthesis method and subsequent calcinations. Well-dispersed spherical 2SnO∙(H2O) particles could be synthesized at room temperature through the modified polyol method using tin (II) 2-ethylhexanoate as the precusor, 1,2-propanediol as the solvent, PVP as the capping agent, and sodium borohydride as the reducing agent. The 2SnO∙(H2O) nanoparticles agglomerated to form larger particles during the drying step, and most of these larger nanoparticles coalesced with one another. Finally, these 2SnO∙(H2O) nanoparticles were successfully transformed into the SnO2 phase by calcination for 1 h at 500 °C.
Machinability Studies of Peripheral Milling on Pearlitic Cast Iron
Authors: Babu R. Praveen , Praveen K.
Published: April 2013

Cast Iron with high carbon content is the most commonly used material for machine tool components such as slide guide ways, tables and columns etc, due to its excellent vibration damping characteristics and easy to cast part features. Although it is very easy to cast, cast iron with high carbon content is extremely hard thus making it very difficult to machine. Normally Poly Crystalline Boron Nitride (PCBN) or diamond tipped tools are used for machining these types of Cast Iron to get good surface finish with less tool wear. Unfortunately, cost of these cutting tools is high. Hence it leads to high production cost. In this direction, an attempt has been made to explore the feasibility of machining cast iron with K20 carbide milling cutter with peripheral milling on two different work pieces, one is with heat treated and another one is without heat treated. Tempering process was carried out for heat treatment. Result shows that heat-treated work piece performs well in all aspects compared to non-treated work piece.
Surface of Cast Iron after Laser Hardening
Authors: Němeček Stanislav
Published: April 2013

Laser surface hardening of cast iron is not trivial due to the material’s heterogeneity and coarse-grained microstructure, particularly in massive castings. Despite that, hardening of heavy moulds for automotive industry is in high demand. The present paper summarises the findings collected over several years of study of materials structure and surface properties. Phase transformations in the vicinity of graphite are described using examples from production of body parts in automotive industry. The description relates to formation of martensite and carbide-based phases, which leads to hardness values above 65 HRC and to excellent abrasion resistance.
Effect of Coupling Agent on Mechanical and Thermal Behaviour of Oil Palm/Jute Hybrid Composites
Authors: Jawaid Mohammad , Hassan Azman , Khalil H.P.S. Abdul
Published: April 2013

Hybrid composites prepared by using oil palm empty fruit bunch (EFB) and jute fibres as reinforcement in epoxy matrix by keeping the EFB/jute fibre weight ratio constant at 1:1. In this study, effect of coupling agent on tensile and flexural properties of oil palm empty EFB/jute fibres reinforced epoxy hybrid composites evaluated. Hybrid composites are prepared by using hand lay-up technique. Particular interest is the effect of coupling agent (CA), 2-Hyroxy ethyl acrylate (HEA) on the tensile and flexural properties of hybrid composites. The laminates coupled with HEA showed better tensile and flexural properties than the one without coupling agent. The highest tensile and flexural strength value has been obtained for hybrid composite of jute/EFB/jute (CA). Tensile fracture composite specimens were analyzed by using scanning electron microscopy (SEM) to know the morphological behaviour of composites. Thermal properties of the hybrid composites were investigate to observe the effect of 2-Hyroxy ethyl acrylate (HEA) on thermal stability of hybrid composites.
Mechanical Properties of Chitosan Modified Montmorillonite Filled Tapioca Starch Nanocomposite Films
Authors: Abdul Ghani Siti Waqina , Abu Bakar Aznizam , Samsudin Sani Amril
Published: April 2013

This study was carried out to develop renewable and degradable plastics film with good mechanical properties. The mechanical properties between compatibilized montmorillonite (MMT)/chitosan filled tapioca starch (TPS), uncompatibilized MMT/TPS, and chitosan/TPS nanocomposite films were investigated. Experimental works were started with the extraction of local chitosan from chitin derived from prawn shells which involving deprotenization, demineralization and deacetylation treatments. Degree of deacetylation of chitosan was determined using infrared spectroscopy method. Chitosan was acted as compatibilizer between MMT and starch in order to improve the dispersion of MMT in nanocomposite systems. Nanocomposite films were prepared using a solution casting method with addition of glycerol as the plasticizer. The starch solution was cast onto PTFE mold with cavity thickness of 0.5mm. Characterizations of the nanocomposite films were done using Fourier Transform Infrared Analysis (FTIR). Tensile properties of nanocomposites were investigated. The compatibilized nanocomposite films, chitosan/MMT/TPS give significant effects to tensile properties. Chitosan has played its role as the compatibilizer and also as flexibility improvers to nanocomposite films because elongation at break improved after addition of chitosan.
Study on Fly Ash Based Geopolymer for Coating Applications
Authors: Mohd Mustafa Al Bakri Abdullah , Jamaludin Liyana , Hussin Kamarudin , Binhussain Mohammed , Ghazali Che Mohd Ruzaidi , Izzat Ahmad Mohd
Published: April 2013

Geopolymer is cementitious binders that do not require the presence of ordinary Portland cement (OPC). Fly ash with geopolymer formulations prepared with mixing alumino-silicate with the alkaline activator solution has been applied as protective coating material that suitable for high temperature applications such as fire resistant panel. Geopolymer coating samples were cured at 70 °C for 24 hours before sintered using temperatures range from 600 °C to 1500 °C in order to increase strength and improve thermal properties. Curing conditions also have a significant effect on the development of mechanical strength in most cementitious systems. The chemical compositions, microstructure and FTIR were studied. Geopolymer coating samples cures to a glassy texture and effectively used to create a resistant surface. Fly ash geopolymer coating was improved the compressive strength of the coatings materials as high as 40 MPa. This technology develop a geopolymeric mix design that superior use as cementitious coatings with high thermal application.
Corrosion Behavior of X52 Steel in High Pressure CO2 Environment
Authors: Mustafa Abdel Hafiz , Ariwahjoedi Bamban , Ismail M.C.
Published: April 2013

Research in high pressure CO2 environment is important in oil and gas industry due to potential development of high pressure CO2 gas fields. Current understanding limits the use of carbon steel pipeline material in this high pressure CO2 environment due to excessive corrosion rates predicted by corrosion prediction software. The aim of this work is to elucidate the corrosion behavior of X52 steel in high pressure CO2 environment. Electrochemical methods of linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques were employed to study the CO2 corrosion mechanism at high pressures of 10-60 bar at ambient temperature. Surface morphology and chemical composition of corrosion film was studied by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results obtained showed that the corrosion rates at high pressures were significantly influenced by CO2 pressure. However FeCO3 and F3C were the main component of the corrosion product film.
Corrosion Behaviour of Lead-Free and Sn-Pb Solders in 3.5wt% NaCl
Authors: Kamarul Asri Asma , Hamzah Esah
Published: April 2013

The current need to produce lead-free solders in the electronic industries makes it necessary for the replacing solders to have properties which are comparable if not better than the conventional Sn-Pb solders. Thus this research was conducted to compare the corrosion behaviour of lead-free solders with composition Sn-4.0Ag-0.5Cu (SAC405), and Sn-3.0Ag-0.5Cu (SAC305) with conventional Sn-37Pb solders. Corrosion tests were conducted using salt spray tests with 3.5% sodium chloride (NaCl) solutions. The samples were characterized after corrosion tests by using SEM, EDS and XRD. The results showed that the elements present in the solders contributed to galvanic corrosion mechanism that affected the overall corrosion behaviour of the solders.
Fabrication and Characterization of Ceramic Membrane by Gel Cast Technique for Water Filtration
Authors: Ahmad Norhayati , Binti Mohd Zaidan Nurhanna , Mohd Bazin Maisarah
Published: April 2013

Sayong ball clay membrane can be fabricated without the assistance of high-tech sophisticated machineries and complicated production methods make the filters particularly attractive as a point-of-use treatment. This work was concerned with the study of Sayong ball clay membrane as a water filtration by Gel Cast technique. Gel cast involves mixing process of Sayong ball clay with the solvent, monomer, dispersant, initiator and catalyst in a certain composition Tubular membrane was designed and fabricated by controlling the Gel Cast monomer (5, 10, 15, 20 MAM percentage) at sintering temperature of 1300°C. The physical measurements (shrinkage, apparent porosity, bulk density), microstructure analysis, filtration process (flow rate) and water quality assessments (pH, color, COD, SS) were carried out at different percentage of MAM. The porosity and density of membranes were measured by using Archimedes method. The effect of monomer percentage on microstructure of the membranes has been investigated using FESEM. The experimental results showed that the apparent porosity and bulk density of Sayong Ball Clay Gel Cast with 5% MAM and sintered at temperature of 1300°C for 20 minutes were 15.39% and 1.87 g/cm3, respectively. It gives improvement in water quality with the lowest suspended solid (192 mg/L), lowest COD (4 mg/L) and most colorless (1.1 Gardner units) filtered wastewater as compared to others.
Study on Fabrication of Ceramic Membrane from Shirasu Balloon for Waste Water Filtration
Authors: Ahmad Norhayati , Yuzo Nakamura , Kamibayasi Hiroki , Mohamed Bazin Maisarah
Published: April 2013

The fabrication of low cost ceramic membranes for microfiltration were studied by using a natural materials (shirasu balloon) which are produced from glassy volcanic materials. The shirasu powder was formed into cylindrical shaped membranes and sintered at five different temperatures from 600 °C to 800 °C using spark plasma sintering (SPS). The porosity and density of membranes were measured according to Archimedes method. The effect of sintering temperatures on microstructure and phase of the membranes has been investigated using FESEM and XRD. A filtration experiment was carried out to study the membrane performance for waste water filtration. The quality of the filtered water was determined by analyse the pH, turbidity, suspended solid, chemical oxygen demand (COD) and biochemical oxygen demand (BOD5). The porosity reduced from 48.9% to 40.32% while the membrane density increased from 1.15 g/cm3 to 1.33 g/cm3 with increasing sintering temperatures from 600 °C to 800 °C. A little shrinkage occur during spark plasma sintering process. From the FESEM microstrcture, the maximum pore size of the membrane that has been observed at 600 °C is about 4.7 µm. Shirasu membrane are able to produce clean and clear treated water during the microfiltration test with membrane sintered at 800 °C and there is an improvement in quality of water that has been filtered. The ceramic water filter was successfully produced without the involvement of the high-tech, sophisticated machines and methods as well as complex materials
Effect of Electrolyte Volume Ratio on Electroluminescence of Porous Silicon Nanostructures (PSiNs) Intensity
Authors: Ain Zubaidah M. , Asli N.A. , Rusop Mohamad , Abdullah Saifollah
Published: April 2013

For this experiment, the main purpose of this experiment is to determine the electroluminescence of PSiNs samples with optimum electrolyte volume ratio of photo-electrochemical anodisation. PSiNs samples were prepared by photo-electrochemical anodisation by using p-type silicon substrate. For the formation of PSiNs on the silicon surface, a fixed current density (J=20 mA/cm2) and 30 minutes etching time were applied for the various electrolyte volume ratio. Volume ratio of hydrofluoric acid 48% (HF48%) and absolute ethanol (C2H5OH), HF48%:C2H5OH was used for sample A (3:1), sample B (2:1), sample C (1:1), sample D (1:2) and sample E (1:3). The light emission can be observed at visible range. The effective electroluminescence was observed for sample C. Porous silicon nanostructures light–emitting diode (PSiNs-LED) has high-potential device for future flat screen display and can be high in demand.
Transparent Ultraviolet Sensors Based on Magnetron Sputtered ZnO Thin Films
Authors: Hoon Jian Wei , Chan Kah Yoong , Ng Zi Neng , Tou Teck Yong
Published: April 2013

Ultraviolet (UV) sensors have variety of applications. In this work, a new transparent UV sensor is developed based on zinc oxide (ZnO) films. The ZnO films with 350 nm thicknesses were fabricated on glass substrates by using direct current (DC) plasma magnetron sputtering technique. The ZnO UV sensors are characterised by using current-voltage (I-V) measurements at room temperature. The current is measured by applying small bias voltage under the white light, UV light (325 nm), and dark condition and the photocurrent responses extracted from the I-V measurements are compared. The transparent UV sensors based on ZnO films deposited at high substrate temperature of 450 °C exhibit most significant photocurrent response under UV irradiation.