bluuebunny/crossref_metadata_2025 huggingface dataset:
Polycaprolactone(PCL)/Chitosan(Cs)-Based Scaffold by Freeze Drying Technique for Tissue Engineering and Drug Delivery Application
Authors: Zarith Nadira Zamal , Sultana Naznin
Published: November 2014

Tissue engineering is the promising technique to replace organ transplant in order to solve many problems regarding the shortage of organ donor and other problems related to organ or tissue transplantation such as bleeding, diseases, accidents and others. Polycaprolactone (PCL) and chitosan (Cs) are biodegradable polymers that have the properties to develop into scaffold. Both of the polymers were used in this research in order to produce scaffold by using freeze drying technique. Four samples of scaffolds were fabricated with the variety of concentration chitosan, PCL 10% (1g of PCL in 10ml glacial acetic acid), PCL/Cs 11% (1g of PCL and 0.1g of chitosan in 10ml glacial acetic acid), PCL/Cs 12% (1g of PCL and 0.2g of chitosan in 10ml glacial acetic acid) and also PCL/Cs 13% (1g of PCL and 0.3g of chitosan in 10ml glacial acetic acid). The produced scaffolds had good properties from both polymers such as faster degradation rate, hydrophilic, porous and others.
Modification of Montmorillonite with Diamine Surfactants
Authors: Zaini Mahirah , Majid Rohah A. , Nikbakht Hossein
Published: November 2014

Sodium montmorillonite (Na-MMT) was modified with various type of diamine surfactants. The modification imparts hydrophobic characters of MMT, thus enhancing its compatibility and dispersibility in polymer matrix. In this research, pristine MMT was modified with three types of diamine surfactants, namely, 1,3 diaminopropane (DAP), 1,8 diamino octane (DAO) and 1,5 diamino-2-Methyl pentane (DAMP). These diamines have different molecular structures where DAP has a short linear structure, DAO has eight carbons while DAMP has a methyl branch on its backbone. The modification was carried via cationic exchange process. X-ray diffraction (XRD) analysis showed the enhancement of d-spacing of MMT galleries and the formation of intercalated structure with the incorporation of diamines. Overall, type of diamines did not give significant effect on the d-spacing values with DAMP-MMT exhibited a slightly higher d-spacing at 13. 36 Å. The presence of methyl branch on the DAMP backbone was thought provide more spacing for the diamine to intercalate through the MMT gallery. Meanwhile, the detection of –NH bending amine group at 1470 cm-1 on the Fourier infrared (FTIR) spectra, corresponding to the free surfactant tail, had confirmed the successfulness of cationic exchange reaction between the diamines and MMT surface.
Evaluation of Palm Biodiesel - Diesel Blending Properties, Storage Stability and Corrosion Behavior
Authors: Mat Ramli , Wan Nor Yuhaidi Wan Nurul Aini , Kamaruddin Mohd Johari , Hassan Onn
Published: November 2014

Palm Biodiesel, which can be produced from transesterification palm oil with methanol, is an alternative fuel for diesel engines. It can be mixed with diesel fuels and used in diesel engines with no or slight modification. Therefore, in this study, commercially available diesel fuel was blended with biodiesel produced from transesterification of palm oil. The stability of the pure palm biodiesel (B100) was investigated over a storage time of 2, 4 and 6 months. The study assessed the corrosion rate of metals exposed to palm biodiesel. The kinematic viscosity, density and flash points of the blends increased with biodiesel amount in the fuel blend. However, pour point of the blends decreased as the amount of biodiesel in the blends is increased. Kinematic viscosity, pour point and flash point slightly increased with storage time. The average corrosion rate for copper is 0.5341 mpy, 0.2438 mpy for aluminium and 0.1802 mpy for mild steel.
Effect of Carbon Nanotube on the Mechanical Properties of Compatibilized Polylactic Acid/Natural Rubber Blend
Authors: Mohammad Nor Nisa Balqis , Arsad Agus , Rahmat Abdul Razak , Mat Des S.Z. , Abdullah Sani Nur Syazana
Published: November 2014

Polylactic acid (PLA)/ Natural rubber (NR) in the presence of PLA grafted Maleic Anhydride (PLAGMA) as compatibilizer was prepared by the melting blend method. In attempt to achieve high performance of the blend, nanocomposites were formed by incorporating different ratio of carbon nanotube (CNT) in PLA/NR/PLAGMA blend. The effect of CNT content on mechanical properties was investigated. With increasing CNT content, Young’s modulus and flexural modulus were increased firstly and then decreased as CNT was further added. In other hand, impact strength was dropped as expected as the CNT loading was increased.
Sustainable Removal of Heavy Metal Using Extracted Pandanus amaryllifolius Roxb.
Authors: Ngadi Norzita , Yahya Noor Yahida , Abd Rahman Roshanida
Published: November 2014

Discharge of heavy metals from metal processing industries is known to have adverse effects to the environment. Conventional treatment technologies for removal of heavy metals from aqueous solution are not economical and generate huge quantity of toxic chemical sludge. Biosorption of heavy metals by metabolically inactive non-living biomass of microbial or plant origin is an innovative and alternative technology for removal of these pollutants from aqueous solution. Therefore, in this study, it is aimed to investigate the potential of pandan leaves as a biosorbent to remove heavy metal, copper. The pandan leaves were extracted via solvent extraction method. The effect of dosage of biosorbent, pH aqueous solution, and the biosorption contact time towards removal of copper (Cu2+) ions were studied. The concentration of copper ions was analyzed by using atomic adsorption spectroscopy (AAS). The maximum biosorption of Cu2+ ions was obtained up to 70 % for 5ppm of initial copper ions loading by 1 hour.
Thermogravimetric Kinetic Behavior of Malaysian Poultry Processing Dewatered Sludge (PPDS) during Combustion
Authors: Aniza N. , Hassan Suhaimi , Nor M.F.M , Fadhil M.
Published: November 2014

The combustion characteristic and kinetic analysis of Malaysian poultry processing dewatered sludge (PPDS) from two different origins, namely as PPDS 1 and PPDS 2 using Thermogravimetric analysis (TGA) were examined. The non-isothermal step was practiced under oxidative atmosphere during the investigation. The temperature was ramped from 30oC to 1000oC at four different heating rates to allow the calculation of kinetic analysis parameter i.e. activation energy. Derivative thermogravimetric (DTG) curves for both samples resulted from TGA shows 3 different peaks. Calculation of apparent activation energy was adopted using iso-conventional model free method. The different of activation energy value embedded in each samples was due to the non-similarity of its fuel characteristic and combustion behavior.
Effect of Viscosity and Heating Temperature on an Intermittent Spray Jet of Starch Dispersion
Authors: Naz Muhammad Yasin , Sulaiman Shaharin Anwar , Ari-Wahjoedi Bambang
Published: November 2014

In this paper, an attempt was made to integrate the effect of jet injection time, load pressure and solution physical properties on jet breakup parameters. A starch-urea-borax complex solution was prepared and tested with an axi-symmetric full cone nozzle. The jet injection time was set to 100, 200, 300 and 400, the solution heating temperature was set to 20°C and 80°C ms, the load pressure was set to 1, 2, 3, 4, and 5 bar, and corresponding spray patterns were imaged by using a high speed camera. The imaging study of the developing spray patterns revealed that the unheated solution forms only spinning jets for all used load pressures. No jet breakup was seen in the near and far-nozzle imaged regions except at 5 bar load pressure, where minor spreading in the jet was seen after 80 mm downstream of the nozzle exit. At 80°C temperature and 5 bar load pressure, very dense spray patterns with an increased spray cone angle were emerging from the nozzle. After 300 ms of injection time, these developing spray jets were changed into fine spray patterns.
Carbonated Water Injection for Recovery of Oil and Wettability Analysis
Authors: Mat Ali Mohamad Faizul , Junin Radzuan , Md Aziz Nor Hidayah , Salleh Adibah
Published: November 2014

Malaysia oilfield especially in Malay basin has currently show sign of maturity phase which involving high water-cut and also pressure declining. In recent event, Malaysia through Petroliam Nasional Berhad (PETRONAS) will be first implemented an enhanced oil recovery (EOR) project at the Tapis oilfield and is scheduled to start operations in 2014. In this project, techniques utilizing water-alternating-gas (WAG) injection which is a type of gas flooding method in EOR are expected to improve oil recovery to the field. However, application of gas flooding in EOR process has a few flaws which including poor sweep efficiency due to high mobility ratio of oil and gas that promotes an early breakthrough. Therefore, a concept of carbonated water injection (CWI) in which utilizing CO2, has ability to dissolve in water prior to injection was applied. This study is carried out to assess the suitability of CWI to be implemented in improving oil recovery in simulated sandstone reservoir. A series of displacement test to investigate the range of recovery improvement at different CO2 concentrations was carried out with different recovery mode stages. Wettability alteration properties of CWI also become one of the focuses of the study. The outcome of this study has shown a promising result in recovered residual oil by alternating the wettability characteristic of porous media becomes more water-wet.
Computational Analysis of Nanofluids in Vehicle Radiator
Authors: Che Sidik Nor Azwadi , Yen Cheong N.G. , Fazeli Alireza
Published: November 2014

Nanofluids are basically nanoparticles in base fluids. Nanofluids have unique features different from conventional solid-liquid mixtures in which nanosized particles of metals and non-metals are dispersed. Due to enhancement of mechanical properties, nanofluids are widely used in heat transfer industries. Two type of base fluids which are water and 50-50 mixture of Ethylene Glycol with water (EGW) are tested. Copper (Cu) and Alumina (Al2O3) nanoparticles with volume fraction or concentration of 0.5 percent and 5 percent are examined in this study. In the recent decades, car manufacturers are exploring nanotechnology and applying onto mass production car such as Hybrid car that symbolize green products. Nanofluids in car radiator will increase heat transfer of the engine, reducing radiator size hence reducing fuel consumption and higher efficiency. On the other hand, water based nanofluids have better heat transfer compared to EGW based nanofluids. Results also show higher concentration will have better heat transfer. Thermal conductivity of nanoparticles will directly affect the thermal conductivity of the nanofluids and it is proportional related.
The Effects of Winding Angles and Elevated Temperatures on the Crushing Behaviour of Glass Fibre/Epoxy Composite Pipes
Authors: Fitriah S.N. , Abdul Majid M.S. , Daud R. , Afendi Mohd
Published: November 2014

The paper discusses the crushing behavior of various winding angles of glass fibre reinforced epoxy (GRE) pipes at elevated temperatures. Two different winding angles of composite pipes were chosen for the study; ± 55°, ± 63°. GRE pipes angled ± 55° and ± 63° are compressed using Universal Testing Machine (UTM) at room temperature and elevated temperatures of 45°C, 65°C, and 95°C according to ASTM D695-10 standard. The temperatures were chosen based on the glass transition temperature (Tg) that was measured earlier. The results show that as the temperature is increased, the compressive strength significantly degraded. This is due to the change in the properties of the GRE pipe from a rigid state to a more rubbery state as the composite pipe reached Tg. GRE pipe with winding angle ± 55° show a higher compressive strength compared to ± 63°.
Numerical Simulation of Stress Change during Wellbore Injection
Authors: Bataee Mahmood , Irawan Sonny
Published: November 2014

The important matter during any process in the well is wellbore integrity. Regarding to the geomechanics of the well, high bottom-hole pressure and low temperature could lead to the fracturing. The stress near the wellbore is a function of the flow and temperature, and it precisely determined to avoid the wellbore failure. The objective of this paper is to simulate stress change in the well for the injection. In order to analyze the stress in the wellbore a finite volume analysis has done for the wellbore. The stress equation relates to flow equation with the equation of principle stress. It means that the pressure is a key parameter for determination of the stress. The procedure which has to be followed is transforming the equations to weak form, meshing the defined shape and programing to obtain the values for each node. The result for the stress is obtained for some meshed bodies. The accuracy enhanced by choosing smaller mesh sizing.
The Effect of Binder on Mechanical Properties of Kenaf Fibre/Polypropylene Composites Using Full Factorial Method
Authors: Amran Mohd , Izamshah Raja , Hadzley Mohd , Shahir Mohd , Amri Mohd , Sanusi Mohd , Hilmi Hazwani
Published: November 2014

The effect of maleated polypropylene (MAPP) as binder on the mechanical properties of kenaf fibre/polypropylene (KF/PP) composites is studied. Ratios between kenaf fibre and PP having 10:90, 30:70 and 50:50 in weight ratio were selected. Further, MAPP having 1, 3 and 5 percent in percentage of weight ratio was mixed in KF/PP composites. Hot press machine was used to produce tensile test samples of KF/PP composites. The mechanical properties that are tensile strength, tensile modulus and elongation at break of KF-PP composites were obtained from tensile test result. It is found that the tensile strength and tensile modulus increase with increasing the kenaf fibre loading and higher percentage of MAPP. Further, the elongation at break for KF/PP composites shows lower result when increasing of kenaf fibre loading. However, when percentage of MAPP added in KF/PP composites increases, the elongation at break increased slightly. Thus, result shows that kenaf fibre/PP composites with binder were better in tensile strength, tensile modulus however the elongation at break shows weak result unless the binder was added.
New Approach for Fabrication of Auxetic Foam and Determination of Poisson's Ratio
Authors: Mozafar Shokri Rad , Zaini Ahmad
Published: November 2014

Conventional foam could be converted to auxetic foam under auxeticity process. A new and simple technique to fabricate auxetic foam and to further determine its Poisson’s ratio is described in this paper. It is evident that the present modified technique in fabricating auxetic foam could be adopted to produce desirable auxeticity characteristics. Moreover, the approach used for determination of Poisson’s ratio has considerably merit with great cost effectiveness. This method is, however, specific to auxetic foam sample under compression loading.
Vibration Response Behaviour of Glass Fibre/Epoxy Laminates at Various Volume Fractions
Authors: Farhana N.I.E. , Abdul Majid M.S. , Paulraj M.P. , Helmi E.A.
Published: November 2014

The paper presents the vibration response investigation of glass fibre/epoxy composite plates of different volume fractions. The different in composition of glass fibre is expected to yield different response hence can be used to determine the properties of the material. The laminate samples were prepared by compressed moulding process at volume fractions of 35%, 40%, 45% and 50% with 5mm thickness. Vibration signals at different volume fractions were then measured and the natural frequencies and damping factor were obtained. Feature extraction algorithms with respect to time and frequency domain were developed by means of signal processing methods to classify the signals according to the property of the materials. That indicates the vibration signals obtained shows potential to be used as non-destructive means for detecting the laminates composition.
Analysis of Lightweight Concrete “Cakar Ayam” Foundation for Road Construction using Plaxis 3D Foundation Software
Authors: Mat Nor Ahmad Hakimi , Yahuda Aklil Hamdee , Pakir Faizal
Published: November 2014

Road settlement often occurs because that soil cannot accommodate the load capacity. Therefore, the study to analysis of lightweight concrete “cakar ayam” foundation was conducted. The idea of “cakar Ayam” concept was introduced by Prof. Dr. Ir. Sediyatmo. Objective of these studies was achieved which is to determine the settlement value of lightweight concrete “Cakar Ayam” foundation design on soft clay, sand, clayey silt under the different loads. Hence, the effectiveness of lightweight concrete “cakar ayam” foundation on that soil, have been able to determined according the settlement value was obtained. Implementation of research was doing using Plaxis 3D foundation software. The foundation design was various according to the several of the column length. The slab thickness, spacing between column, foundation and column size was fixed. Soil parameters to analyse lightweight concrete “cakar ayam” foundation, was obtained from previous studies and Research Center of Soft Soil, Universiti Tun Hussien Onn Malaysia, (RECESS, UTHM). Each design was tested by different loads to get the settlement value. From the results show, the settlements value was obtained show concept of “cakar ayam” foundation, not effective to be implement on soft clay. The settlement value was over 25 mm, when the load 20 kN/m2 was applied on the foundation, to all length of column on soft clay. However, the settlement value was lower than 25 mm, when the load 40 kN/m2 was applied on the foundation, to all length of column on sand and clayey silt. From all the settlement value, it could be seen that clayey silt result was more effective than sand. The settlement value also was decrease when the length of pile was increase. In conclusion, the objective of the study was achieved.
A Study of Soil Stabilization by Hydrated Lime at Kampung Kedaik Asal, Rompin, Pahang, Malaysia
Authors: Zukri Azhani , Ghani Nadiatul Adilah Ahmad Abdul
Published: November 2014

This study involves the clay sample which is taken from Kampung Kedaik Asal, Rompin site and evaluation of its properties in natural state and after stabilization. The main objectives of this paper is to estimate the optimum lime content (OLC) needed to stabilize the soil by using Eades-Grim pH Test, to determine the optimum moisture content (OMC) and maximum dry density (MDD) of the treated soil by Standard Proctor Test and also the strength value of the soil specimens with different percentages of lime content corresponding with different curing period by Unconfined Compressive Strength (UCS) Test. From this study, the optimum amount to stabilize the clay soil and minimum amount of lime required to stabilize the soil pH level to 12 is 5%. The results showed that addition of lime decreased the maximum dry density (MDD) and increased the optimum moisture content (OMC). Unconfined compressive test on 48 sets of samples has been carried out for 7, 14 and 28 days of curing with different lime contents such as 5%, 7% and 9%. The highest unconfined compressive strength (UCS) achieved is 321 kN/m2 for clay stabilized with 9% lime content cured at 28 days. From the test results, it was found that the longer the immersion of curing period with higher lime content, the greater the compressive strength of the specimen.
Simulation of a Double-Effect Solar Absorption System for Traditional House in Yemen
Authors: Zaid Ahmed Osamah , Ani Farid Nasir
Published: November 2014

During the last few years, the awareness of the pollution and the global warming has dramatically increased which encourage the researchers around the world to find an alternative source of energy. One of the most efficient sources of energy is the solar energy especially for cooling and heating applications. This paper, described the simulation of a double-effect solar absorption system in Yemen using water lithium bromide solution as a working fluid. The system will be applied to a typical traditional house in Yemen. The performance of the system will be analyzed based on different high pressure generator temperature for the yearly solar radiation data. At higher pressure generator temperature, the results show a higher coefficient of performance of the system. This simulation also estimate high pressure generator heat transfer required to operate the system. As a result, the size of solar collector area and the cost of such system will be calculated.
Combustion Characteristics Modeling of Rice Husk as Fuel for Power Plant in Indonesia
Authors: Anshar Muhammad , Ani Farid Nasir , Kader Ab Saman
Published: November 2014

This study was conducted to obtain a model combustion characteristic of rice husk as fuel at power plants in Indonesia. It is expected to be one of the solutions to meet the needs of electrical energy in Indonesia. Modeling characteristics performed using Ansys Fluent software. Modeling results obtained maximum gas temperature at bed about 1600 K. Temperature and CO2, CO, H2O occurs fluctuation in the combustion zone to at distance of 4.66 m from the fuel inlet. Maximum combustion temperature at the base of the furnace about 1600 K and the furnace exit around 967 K. Temperature distributions in the bed and the furnace is uneven due to incomplete combustion of gas in the bed and the fuel air mixture ratio is not appropriate (stoicheometric). Combustion gases in the furnace, ie CO2, CO, H2O fluctuations at the basic furnace, the furnace chamber, and the furnace exit. It was concluded that the model of combustion characteristics of rice husk can be used as a basis for assessing the feasibility of utilization as fuel for power plants.
Feature Extraction of Knee Joint Vibroarthrographic (VAG) Signal Using Statistical Means
Authors: Tan Hui Ling , Bin Salleh Ahmad Faizal , Norasmadi Abdul Rahim , Wan Mohd Zuki
Published: November 2014

The purpose of the present preliminary investigation is to characterize the vibration signal between normal and symptomatic knee joint. Accelerometers were attached to the medial and lateral retinaculum of dominant knee to acquire the vibration signal induced during flexion and extension of leg. Signals were compared in time and frequency domain and statistical analysis were performed using mean, variance, standard deviation, skewness and kurtosis. The results show that the frequency range for the symptomatic VAG signal is higher than the normal. The results confirm that the proposed approach is indeed feasible for the non-invasive diagnosis of knee pathology disorders.
Investigation of Lightning Distribution Using LIS Data from TRMM Satellite
Authors: Yusop Norbayah , Zainal Siti Hawa , Mohd Aris Nor Azlan , Chachuli S.A.M. , Yunus Mawarni Mohamed
Published: November 2014

This paper presents an investigation on lightning distribution using Lightning Imaging Sensor (LIS) data from Tropical Rainfall Measuring Mission (TRMM) satellite. The investigation is carried out on distribution and variability of total lightning occurred in the area of Washington DC (38.54°N, 77.2°W) during January to April 2011. LIS captures emissions that occurred in the atmosphere which emitted by lightning discharge by covering the most between ±35o in latitude. The lightning distributions are characterized based on monthly, daily, hourly and seasonal basis. The maps of global distribution of lightning flashes have been used as initial data. This analysis shows that a total number of 3.5 million flashes were detected during four months observation. The highest number of flashes recorded in April is about 3.4 million flashes compared to the 3,993 flashes in January. In terms of seasonal, this observation show that the spring season during March and April has highest occurrence of lightning which is 53.2% compared to the winter season in January and February which only 46.8%. This study can provides expected variations of the lightning distribution on the diurnal and seasonal basis, thus make it useful in describing the Earth’s climate.
Effect of Fibre Loading on the Flexural Properties of Natural Fibre Reinforced Polymer Composites
Authors: Davindrabrabu Mathivanan , Januar Parlaungan Siregar , Dandi Bachtiar , Mohd Ruzaimi Mat Rejab , Cionita Tezara
Published: November 2014

The use of pineapple leaf fibres as reinforcement in plastics had increased rapidly in past few years. Thus this project was conducted to determine and compare the flexural strength of pure epoxy and pineapple leaf fibres reinforced epoxy. The natural fibres were mixed with epoxy and hardener by weight percentage fibre content. The process employed to fabricate the specimens was hand lay-up and the natural fibres was oriented randomly. The dimensions of the specimens for flexure test were based on ASTM D790 respectively. The results obtained shows that 15% PALF reinforced epoxy composite achieved the highest flexural strength among the natural fibers reinforced epoxy composites.
Anticorrosion Epoxy Coating Enriched with Nanozinc and Montmorillonite (MMT)
Authors: Nima Moazeni , Mohamad Zurina , Siti Najihah Abdul Manan , Ngadi Norzita
Published: November 2014

The main objective for this research is to compare the performance of hybridization and evaluating best content of nanozinc powder/MMT enriched epoxy coating towards corrosion resistance with nanozinc dust epoxy and plain epoxy coating. The nanozinc contain is fixed at 1 wt% while MMT content was varied from 0.5, 1.0 and 1.5 wt%. The corrosion resistance of epoxy/MMT/nanozinc coated substrate was evaluated by analysis of salt spray test (ASTM B117 and D-1654).
Electrochemical Behaviour of High Stress Steel (AISI 4340) in CO2 Environments with the Presence of H2 Gas
Authors: Asmara Yuli Panca , Siregar Januar Parlaungan , Cionita Tezara , Alias Juliawati
Published: November 2014

This research studied the effect of CO2 and H2 gas on electrochemical behaviour of high stress steel (HSS) by using scan polarization graph to measure corrosion rate, corrosion potential and pitting potential. The tensile test samples with and without notches were tested under constant stress of 20% and immersed in 3% NaCl solutions. During experiments, CO2 gas was injected into the samples. To generate H2 gas, the samples were employed cathodically over potential at - 1700 mV (Ag/AgCl) for three days. The results indicated that both CO2 and H2 gases have increased the corrosion rate. Potentiodynamic graph showed that there were changes in pitting potential where the effect of CO2 gas would decrease the pitting potential. However, the presence of the notch did not show any significant difference in corrosion rate.
First-Principles Calculation of Tetragonal Phase Properties of ZnO under High-Pressure
Authors: Yang Cheng , Li De Cong , Li Xiao Pan , Ren De Hua
Published: November 2014

First-principles plane wave pseudopotential method based on the density functional theory is used to study of the evolution rule of the optical properties and electronic structure for ZnO tetragonal phase under different pressure. The results show that the chemical bond between zinc and oxygen is shortened with the increase of the external pressure, while the increase of orbital hybridization between the zinc atom and the oxygen atom. The calculations also show that the band structure of ZnO tetragonal phase changes with the increase of the pressure, and the band gap is broadened, which causes that the optical absorption margin and the optical absorption peak move to the direction of high energy.
Structural and Magnetic Properties of New Type CaxSr1-x-yLayO•nFe(2n-z)/nCoz/nO3 Magnets
Authors: Liu Xian Song , Yang Ji Liang , Yang Hui
Published: November 2014

Considering that Ca2+has the similar ion radius and the substituted ability as Sr2+and Ba2+but the same family, CaxSr1-x-yLayO•nFe(2n-z)/nCoz/nO3ferrites have been synthesized by the conventional ceramic process. Structure and magnetic properties of CaxSr1-x-yLayO•nFe(2n-z)/nCoz/nO3compounds have systematically been investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscope (SEM) andB-Hhysteresis curve measurements. Several compositions are selected to investigate the formation of M phase with the joint replacement of Ca-La-Co. It is found that the formation mechanism is based on the replacement of Sr2+by La3+plus Ca2+and the charge compensation by Co2+. In futher results, the unexpectedly intrinsic coercivity of 436 kA/m and residual flux density of 0.445 T were obtained. In terms of material preparation, we believe that CaxSr1-x-yLayO•nFe(2n-z)/nCoz/nO3is effective in the production of future high energy permanent magnets.
Preparation of Aluminum Nitride Whiskers by Precursor Method
Authors: Xu Hong Zhao , Li Han , Sui Xue Ye , Wang Chong Hai , Zhou Chang Ling , Zhou Chang Ling , Liu Rui Xiang
Published: November 2014

Using melamine and aluminum nitrate as raw material, we prepared aluminum nitride whiskers by precursor method and studied the effect of reactants and concentration to AlN precursor. The results showed that when the Molar ratio is 1:3, and the concentration is 0.2mol/l, whisker precursor produced is relatively uniform and have large length diameter ratio.
Heat Resistance Properties of an Cured ATPU/Epoxy Resin
Authors: Chen Wen Yi , Guan Jian Guo
Published: November 2014

Thermogravimetry (TG-DTA) method was used to study the heat resistance properties and the thermal decomposition kinetics of the aromatic amine-terminated polyurethane (ATPU)/Epoxy Resin System (E-44) which includes both flexible chains and rigid structural units. The results indicate that the decomposition temperature of the cured ATPU-2/E-44 is higher than that of the cured ATPU-1.5/E-44, and thermal decomposition residual of cured ATPU-2/E-44 is higher than that of cured ATPU-1.5/E-44 system. These results denote that the cured ATPU-2/E-44 has better heat resistance. The results of decomposition kinetics showed that the decomposition reaction activity of the ATPU-2/E-44 system is higher than that of ATPU-1.5/E-44.
Sensing Characteristics of Sulfur Dioxide Gas Sensor Utilizing YSZ and Sulfate Salts
Authors: Shi Wang Yan , Li Li Hua , Xu Lu Quan , Li Qiang , Feng Tao
Published: November 2014

A new sensor with Pt and Ag mixture paste on the surface to act as the sensing electrode (Ag) and catalyst (Pt) to oxidized SO2to SO3for sulfur dioxide was fabricated. The effect of auxiliary phase on the sensing properties has been investigated and the device with auxiliary phase showed better performance and the effect of operating temperature has also been studied. It shown that 500°C would be more suitable than 600°C for the device gas test.
Preparation and Characterization of SiC/SiC Micro Ceramic Matrix Composites
Authors: Chen Ming Wei , Qiu Hai Peng , Jiao Jian , Li Xiu Qian , Wang Yu , Zou Hao
Published: November 2014

SiC continuous fiber reinforced SiC ceramic matrix composites (SiCf/SiC CMCs) and SiC fiber reinforced SiC micro ceramic matrix composites (SiCf/SiC micro-CMCs) were prepared through polymer impregnation pyrolysis (PIP) progress, then the structures, mechanical properties and forming mechanisms of SiCf/SiC CMCs were investigated. Results showed that volume shrinkage of SiC matrix occurred, and pyrolysates with bamboo-like layered structure were attached to the surface of SiC multifilament gradually. Furthermore, the mechanical properties of SiCf/SiC micro-CMCs were consistent with SiCf/SiC CMCs, so the PIP process parameters for the preparation of SiCf/SiC CMC might be optimized primarily through SiCf/SiC micro-CMCs, which could enhance the design and preparation efficiency of SiCf/SiC CMCs obviously.Key word: polymer impregnation pyrolysis progress, micro ceramic matrix composites, forming mechanism
Effect of MgO-Y2O3 Additions on Microstructure and Mechanical Properties of Al2O3-TiCN Composites
Authors: Zhang Zhi Lin , Guo Wei Ming , Wu Shang Hua , You Yang
Published: November 2014

The effect of MgO-Y2O3 additives on densification, microstructure and mechanical properties of hot-pressed Al2O3-TiCN composites was studied. The MgO-Y2O3 additions had little influence on densification of Al2O3-TiCN composites. The Al2O3-TiCN composites without additives had coarsening microstructure, whereas that containing 0.25wt%MgO-0.5wt%Y2O3 had a noticeable finer microstructure and good mechanical properties. The increase of fracture toughness were attributed to the addition of MgO and Y2O3 together with the TiCN particles to inhibit the abnormal grain growth of Al2O3.
Densification Mechanism of Antimony-Doped Tin Oxide Ceramics by Spark Plasma Sintering
Authors: Li Qi Zhong , Li Qi Chang
Published: November 2014

SnO2 ceramics were synthesized by SPS. Phase compositions and microstructures are examined by XRD, SEM and EDS, respectively. Sb2O3 used in our research were beneficial to lower the sintering temperature and promote the densification of SnO2 ceramics. The SEM results show a homogeneous microstructure is approached consistent with the density measurement at 850-1000 °C. The XRD show all antimony ions came into the lattice of SnO2 to substitute for tin ions when the content of Sb2O3 are 0.1-2.5 mol%. The grain boundary are no SnO and Sb2O3, only SnO2. The mechanism of SPS sintering process is the local high temperature to produce the abnormal growth of the grain, and evaporation-condensation; and solid solution of Sb3+ go into the SnO2 lattice produce oxygen vacancy to promote densification
Adsorption-Desorption Performances of Humidity Controlling Diatomite-Based Ceramics
Authors: Cheng Xiao Su , Li Zhi , Wang Hui , Liu Ping An , Shui An Ze , Zeng Ling Ke
Published: November 2014

The humidity controlling materials using diatomite as the major raw material were prepared by dry pressing molding process. Effects of various diatomite contents and sintering temperatures on the final products were investigated. The samples were also characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), and then tested adsorption-desorption performances by temperature and humidity chamber. The results indicate that the equilibrium moisture adsorption reaches to 338 g/m2 when diatomite content is fixed at ~70% and sintering temperature is holding at 1050°C, respectively.
Preparation and Properties of Si3N4-SiC-C Refractory Materials Composited with Sucrose and Phenolic Resin
Authors: Yin Zhao Yu , Huang Zhao Hui , Fang Ming Hao , Liu Yan Gai , Wu Xiao Wen
Published: November 2014

Si3N4-SiC-C refractory composites were prepared under the condition of 1100 °C × 1 h with Si3N4and SiC as the raw material and the sucrose and phenolic resin as the binder. The effects of the amount of the sucrose in the binder on the properties of Si3N4-SiC-C refractory composites were studied. The results indicated that increasing the ratio of sucrose in the binder can improve the properties of the materials.
A Comparative Study on Radio-Frequency Thermal Plasma Spheroidization for Two Types of Alumina Ceramic Powder
Authors: Zhu Hai Long , Tong Hong Hui , Yang Fa Zhan , Wang Qin , Cheng Chang Ming
Published: November 2014

To obtain high-performance alumina powder for high-tech application, a comparative study was carried out for the spheroidization of two types of alumina powder using radio-frequency argon-oxygen thermal plasma. The morphology, crystallography, and particle size distribution of spheroidized alumina powder were analyzed. The effect of feed rate on the spheroidization efficiency was investigated. The results show that when the powder flow rate was 35 g/min, the spheroidization efficiency reached up to 100%, and the alumina powder had perfect sphericity, while the spheroidization efficiency decreased with increasing powder flow rate. The X-ray diffraction analysis reveals that the spheroidized alumina powder had mixed crystal structures with a stable α phase and a part of metastable phase. The particle size distribution analysis shows that the particle size of the spheroidized alumina powder did not change obviously. These results will help us to better understand the process engineering of the spheroidization of ceramic powder using radio-frequency argon-oxygen thermal plasma, and provide simultaneously technical assistance for industrialization.
Synthesis and Characterization of Flower-Like Co–La Oxide Micro/Nano Materials
Authors: Lin Shi Jing , Du Wu Tong , Ding Ting Ting , Zhao Yu , Zhao You , Rong Hua , Tong La Ga
Published: November 2014

Flower-like Co–La oxide micro/nanomaterials have been synthesized via an ethylene-glycol-mediated process, under the condition of that the mole ratio of lanthanum nitrate (La (NO3)3·6H2O) and cobalt nitrate (Co (NO3)2·6H2O) was 1:1 (based on the amount of Co (NO3)2·6H2O 0.002 mol), the dosage of urea was 2.2 g, the dosage of tetra-butyl ammonium bromide (TBAB) was 6.0 g, with magnetic stirring heating under 170 °C for 60 minutes in the 150mL ethylene glycol, the prepared precursors of Co–La oxides have regular flower-like morphology, in addition, the amount of TBAB and urea plays a significant role on the synthesis of the precursors. The flower-like Co–La oxides micro/nanomaterials were prepared after the precursors were calcinated in the muffle furnace at 800 °C for 2 h, the morphology, crystal properties and element distribution of the products were investigated by the analysis of SEM-EDX, XRD and BET, etc. The structures of these products with regular flower-like morphology are on the micrometer scale, which are hierarchically composed of nanosized building blocks, with highly polycrystalline nature, and the Brunauer–Emmett–Teller (BET) surface area of 68.5 m2/g. Therefore, those micro/nanomaterials have been developed as promising catalytic materials for their not only keeping the high surface area of nanomaterials, but effectively inhibiting aggregation.
Application of Phosphate Process in Ceramic Insulated Magnet Wire
Authors: Zhang Wen Yuan , Liu Rui Xiang , Yang Jie , Zhou Chang Ling , Sui Xue Ye , Wang Chong Hai
Published: November 2014

In this paper we take advantage of the phosphate film which has a porous structure, by phosphate process on the surface of nickel plated copper conductor so as to improve the bonding force of wire and ceramic layer; Through the study of resistance voltage breakdown after phosphate , phosphate liquid was determined Manganese dihydrogen phosphate for 3g100-1ml, Zinc Nitrate was 8g100-1ml, Sodium Fluoride was 0.45g100-1ml; Optimum temperature was 60°C and the appropriate time was 15min at the temperature of 60°C.
Evaluation of PAN Based Composite Sheet Films with Modified Carbon Nanotubes
Authors: Liu Ren , Yuan Yan , Huang Yu Xia , Liu Yu Lan , Zhang Xiang , Wang Yan Xiang
Published: November 2014

An aqueous deposited polymerization method to fabricate PAN based composite sheet films after multiwall carbon nanotubes (CNTs) modified with concentrated nitric acid was presented. This paper disscussed the effect of CNTs modified with concentrated nitric acid on the thermal and the crystal properties of PAN based composite sheet films. The results indicated that the normal process of multiwall CNTs treated with concentrated nitric acid can change the crystallization properties of polymers but not change the basic structure of polymers. The crystallinity of pure PAN at 2θ≈17° was strengthened after preoxidation. With the addition of CNTs, the crystallization peak of composite sheet films at 2θ≈17° became weaker, and a sharp crystallization peak appeared at 2θ≈25°, as showed that the composite sheet films could carry out the cyclization at low preoxidation temperature. During their process of preoxidation and carbonization, modified CNTs could promote the formation of cyclization and cause the formation of aromatic ring structure, and the cyclization efficiency increased from 20.24% to 70.41%. TEM analysis indicated that the modified CNTs existed in the composite sheet films in two forms: the dispersion and reunite of the single state. The test results of the surface resistivity of the composite sheet films showed that when the CNT content was lower, the surface resistivity of film was very large. When the CNT content was 5% and 10%, the surface resistivity of the film was 5.74 MΩ and 0.15 MΩ, respectively. It was obvious that once the continuous conductive network of CNTs was formed, the surface resistivity of composite sheet films hardly changed.
Preparation of Silver Nanoparticles/Graphene Composite Films by Dip-Coating Method and their Surface-Enhanced Raman Scattering Property
Authors: Zhao Nan , Ma Shuang Biao , Yan Qian Qian , Zhou Ya Zhou , Fu Xiao Qi , Cheng Xiao Nong , Yang Juan
Published: November 2014

Recently, noble metal nanoparticles (Au or Ag NPs) decorated graphene (GE) sheets are used as good surface-enhanced Raman scattering (SERS) substrates for detection of molecules. Ultrathin GE film covered by Ag NPs has been designed for the SERS substrate in this paper. The films were prepared firstly by dip-coating method with graphene oxide (GO) and AgNO3 or Ag NPs colloid as raw materials and secondly reduced by thermal annealing at 600 °C in H2/Ar atmosphere. The structure and SERS activity of the obtained films have been investigated in detail. Results indicated that Ag NPs can be decorated on graphene sheets through the electrostatic adsorption between the GO sheets and positively charged Ag+ or Ag NPs. Compared with the film obtained with AgNO3, Ag NPs/GE film prepared with Ag NPs colloid showed the higher SERS sensitivity with rhodamine 6G (R6G) as the probing molecules, the enhanced factor for 1×10-5 M of R6G adsorbed on the surface of Ag NPs/GE substrate is about 9.1×107.
ZrB2 Nano-Powders Prepared by Sol-Gel Carbothermal Reduction
Authors: Wang Bai Na , Duan Yun Biao , Hu Jin , Wang Yu Tian , Wang Kai Jun , Tao Ying Mei
Published: November 2014

Zirconium diboride (ZrB2) powders were synthesized by sol-gel carbonthermal reduction method using zirconium oxychloride (ZrOCl2·8H2O), boric acid (H3BO3), source (C12H22O11) and citrate (as chelation agent). The Zirconium diboride precursors were calcined at 1600¡æ for 2h, 3h and 4h under argon atmosphere. The precursors and sintered samples were characterized by TG-DSC, XRD and SEM. Results revealed that the ZrB2powders prepared at 1600°C for 4h exhibited quasi-tabular morphology with a small average crystalline size about 20μ. With respect to the conventional solid state method, the Sol-gel method route guaranteed a faster, easier and energy-saving process for obtaining nanopowders.
Impacts of Cr Substitution on Ion Distributions and Electrochemical Performance of LiNi0.5-xCr2xMn1.5-xO4 Cathode Materials
Authors: Shi Xiao Hong , Luo Fei , Zhang Lin , Guo Yu Zhong
Published: November 2014

A spinel-structured LiNi0.5-xCr2xMn1.5-xO4(x=0, 0.05) were prepared via co-precipitation routes. The experiment results from XRD, SEM and electrochemical analyses show that the substitutions of Ni and Cr for Mn in LiMn2O4can not prevent Mn2+from being oxidized into Mn3+in solution process, however,Mn2+oxidation does not change their final crystal structures of spinel phase, but do influence the Li/Ni2+cation mixing and Mn3+occurrence in lattice. After substitution the first charge and discharge capacities decrease but its cycleability is improved significantly, especially for the Ni and Cr co-substitution
Surface Coating and Electrochemical Properties of LiNi0.8Co0.15Al0.05O2 Cathode in Lithium-Ion Cells
Authors: Zhang Lin , Luo Fei , Wang Jian Hua , Guo Yu Zhong
Published: November 2014

LiNi0.8Co0.15Al0.05O2, as the cathode materials for lithium ion battery, were prepared from the precursors, Ni0.8Co0.15Al0.05(OH)2 which were synthesized by chemical co-precipitation method. LiNi0.8Co0.15Al0.05O2 particles are modified with AlF3 and AlPO4. Even though the initial discharge capacity of the coated LiNi0.8Co0.15Al0.05O2 was decreased that of the pristine material, the capacity retention and the thermal stability, in a highly oxidized state are both significantly improved. This effect is attributed to the thin coating layer protecting the oxidized cathode particles from being attacked by hydrogen fluoride in the electrolyte. The cycling behavior of the AlF3-coated LiNi0.8Co0.15Al0.05O2 is quite stable showing good capacity retention (96.3% of its initial capacity after 30 cycles).
Planar Morphology of Silver Leakage at Resin-Dentin Adhesion Interface
Authors: Zhao Xin Yi , Li Shi Bao , Gong Xu
Published: November 2014

The objectives of this in vitro study is to display the overall planar morphology of leakage at resin-dentin interface using ammoniacal silver nitrate as tracer. Twelve human extracted third molars were used and the occlusal enamel of each tooth was removed. All teeth were divided into four groups of three teeth each and bonded with one of four adhesives (Prime&Bond NT, Adper Prompt, Xeno III, Clearfil S3 Bond) and then a composite resin crown was built up. After storage in water (37°C) for 24 h, all teeth were vertically serially sectioned into stick-shaped specimens the bond interfaces. All specimens were immersed in ammoniacal silver nitrate solution, followed by developing solution and subjected to tensile test and the fracture surface were observed with a SEM. The overall planar morphology of leakage at resin-dentin interface appeared to be various tree-like figures, with character of stem-like portion in the periphery and extending from the periphery to the center of the fractured surface and stretching out a lot of branches. Prim&bond NT presented a couple of big tree-like silver deposition extending to center besides many short tree-like figures located along the periphery. Adper Prompt showed short tree-like figures with many branches. Xeno III displayed tree-like figures with thinner stem portion and more branches. Clearfil S3 Bond presented many short shrub-like figures with fewer branches.
Sol-Gel Synthesis of Na2Ta4O11 Nanocrystals Showing High Efficient Photocatalytic Performance
Authors: Su Yi Guo , Yang Xu , Wang Ting Ting , Zhu Bao Ling , Wang Xiao Jing
Published: November 2014

Semiconductors showing high efficient photocatalytic activity have attracted great interest, because they provide a potential solution to many environmental pollution problems that humankind is currently facing. This work reports on the sol-gel synthesis of Na2Ta4O11 nanocrystals and its photocatalytic performance toward Red G. The samples were carefully characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, and the Barrett–Emmett–Teller technique. By modulating the synthetic condition, the sol-gel reaction yielded pure Na2Ta4O11 nanocrystals with diameter of ~32 nm from the peak broadening of (006) plane using Scherrer formula. It is found that the as-prepared Na2Ta4O11 nanocrystals showed a band gap energy of 3.63 eV, which is much smaller than that of Na2Ta4O11 prepared by flux approach. The relative narrowed band gap energy of Na2Ta4O11 nanocrystals may predict superior photocatalytic activity. By careful photocatalytic test, it is found that Na2Ta4O11 nanocrystals showed excellent photocatalytic activity toward Red G. The photocatalytic degradation efficiency was estimated to be 94.0% within a time intervals of 40 minutes. Controlled experiment by adding active species scavengers gave evidence that the degradation of Red G is dominated by the oxidation reaction of the generated O2-∙ active species taking place on the surface of the photocatalyst.