bluuebunny/crossref_metadata_2025 huggingface dataset:
A Narrative Review of Morphology of Cancellous Bone at Different Human Anatomy - Methods and Parameters
Authors: Rabiatul A. Abdul Rahim , Fatihhi Szali Januddi , Harun Muhamad Noor , Kadir Mohammed Rafiq Abdul , Ardiyansyah Syahrom
Published: November 2014

Morphology of cancellous bone has been studied for years, with researchers always seeking accurate methods to assess the parameters. They also study the importance of cancellous morphology in itself. Despite the amount of previous research, there are currently no reviews on the morphology at different anatomy. This paper evaluate the methods and parameters of cancellous bone morphology at different human anatomy. From 1997 to February 2014 we found the articles published on cancellous bone morphology vary in parameters at different anatomy of human bone. Further, researchers are also interested in finding the precision methods for identifying the parameters of cancellous bone. Both in vitro and in vivo were used in finding the accurate result of cancellous bone parameters whilst also searching the importance of the morphology parameters. The morphology studies are vital due to the direct relation with the mechanical properties of cancellous bone. Based on the morphology data, it is found that the morphology parameters are dissimilar at different human anatomy sites. A variety of methods were used by researchers in identifying the morphology parameters, with each method having its own advantages and disadvantages. This review paper summarises the pros and cons of all methods available, in order to help researchers select the best methods for their future studies.
Calculation of Axial Loads on Columns by Tributary Area Method and Finite Element Method
Authors: Mohammad Zaki Mohd Faiz , Mohd Zahid Mohd Zulham Affandi , Ayob Afizah , Fang Tee Chin
Published: November 2014

Basic concept of structural design is to transmit the loading from superstructure to substructure. This idea normally required sound knowledge of structural design and rational engineering judgments. Recently, there have several techniques that can be utilized to determine the superstructure loading, such as finite element method and tributary area method. However, the compatibility of both methods in order to determine the loading from superstructure is prime important and has been investigated in this research framework. Axial loading, represented as products from dead load and service load, which are imposed on the top of slab is directly transmit to the column nearby and modelled through computer simulation. Models of slab were then varies and studies through comparison with broad dimensions of slab thickness, ranging in 100 mm to 600 mm. Results has shown the increasing of slab thickness will indirectly increases the rigidity characteristic of slab and potential to distribute the axial load equally for all column members. Axial load against slab thickness on corner, edge, center, outer and inner column demonstrated the incompatibility for both methods, finite element method and tributary area method in determining the axial loading from superstructure.
Variation of Stress Intensity Factor and Crack Distance Length for Double Edge Crack in Human Femur Bone
Authors: Md Zain Noor A. , Daud Ruslizam , Muhamad W.Z.A.W. , Basaruddin Khairul Salleh , Bajuri Yazid , Abdul Halim Siti Aisyah , Mansor Nurul Najwa
Published: November 2014

The theory of linear elastic fracture mechanic (LEFM) has proven that we can evaluate the amount of stress located at the crack tip by determining the stress intensity factor (). The stress at the tip of a sharp crack has the highest stress which can lead to failure on the material. Thus, the cracks within human bones are quite complicated because of the bone microstructure. There are a few factors that can minimize the effect of the cracks so that patients can heal much faster. Hence, this paper focuses on how several crack distances, between two parallel edge cracks can affect the value of stress intensity factor (). Using the LEFM theory, the interaction between two neighboring crack tips was investigated.
Numerical Simulation of Stress Shielding Induced by Crack Interaction in Human Phalanx Bone
Authors: Abdul Halim Siti Aisyah , Md Zain Noor A. , Mansor Nurul Najwa , Daud Ruslizam , Bajuri Y.
Published: November 2014

Bone fracture is an injury not uncommon to everyday life. Most of the time, it leaves permanent damage and a long period of recovery. This situation can be prevented if we understand the mechanics and the process of the bone fracture. This study aim is to evaluate stress shielding induced by crack interaction using a simple model based on Linear Elastic Fracture Mechanics (LEFM). This simulation based on the determination of the Stress Intensity Factor (SIF) and the changes of stress shielding in different crack interval towards the human phalanx bone. Numerical simulation had been carried out in this project to understand the stress shielding induced by crack interaction. The results revealed that the interaction of two cracks is directly proportional to the SIF magnitude and interaction factor at the crack tips. The parallel cracks have experienced increasing shielding effect as the crack interval increase. The crack interaction limit (CIL) and crack unification limit (CUL) also had been accomplished for every range of crack interval in this project. Several improvements will be conducted for future development of this study, including various stresses loading subjected to the model, porous element added in the model, different planes of the model and use various methods in calculating the stress intensity factor (SIF).
Experimental Investigation and FE Stress Analysis of Adhesive T-Joint with and without Crack in Fluidization Bed
Authors: Nor A. , Afendi Mohd , Abdul Majid Mohd Shukry , Izzawati B. , Nurhashima S. , Abdullah A.R.
Published: November 2014

In this study, investigation on adhesive T-joint with and without crack in urea granulator fluidization bed was carried out by experiment and finite element (FE) analysis. Specimens with and without crack were made from actual size of 1.25 mm perforated plate to duplicate actual structure of granulator fluidization bed and verified using commercial finite element. The existence of crack will affect the strength of adhesive T-joint. The objectives of this project were to examine a series of adhesively bonded T-joints with and without crack under mode I loading, to identify the effective bond thickness by tensile testing and FE analysis. It was found that result pattern from experiment was in agreement with FE analysis.
Analysis of Raft Foundation with EPS Geofoam for Earthquake Resistant
Authors: Mohammad Zaki Mohd Faiz , Ramli Mohammad Fadzli , Ayob Afizah , Ahmad Mohd Taftazani
Published: November 2014

It is becoming a great challenge for civil engineers to design a foundation which able to minimize the effect of an earthquake. A major earthquake produces a strong ground motion in the subsoil and surface structures supported on the soil mass will be induced to move and absorb the dynamic forces. Seismic retrofit of existing foundations is an alternative. However, the modification of this existing foundation toward earthquake resistances raises issues which are far from being totally resolved. Innovative material such as EPS is widely accepted in structural engineering due to its characteristic to absorb the dynamic force effectively. This EPS material demonstrated the practicality and has been applied for geotechnical engineering for various reasons. Based on this, a research which is related to the application of EPS in mitigating the earthquake forces, particularly for raft foundations was conducted properly in this research. The various types and thickness of EPS located beneath the raft foundation and over the soft soil are studied. A finite element program is utilized to develop the computer simulation models. Based on the results, Expended Polystyrene (EPS) Geofoam, placed beneath the raft foundation is able to produces the minimum settlements when subjected to earthquake loading rather than raft foundation modeled without EPS and increasing the density of EPS will simultaneously decrease the settlement of a foundation.
Strength Classification of Aras as Fast-Growing Indigenous Species Timber in Sarawak
Authors: Ismaili Gaddafi , Abdul Rahim Khairul Khuzaimah , Duju Alik , Openg Iskanda , Ismaili Zurina
Published: November 2014

Strength properties’ tests are conducted in the form of small clear sample. This paper aimed to acquire the strength group of fast-growing indigenous species of Aras and exotic species of Acacia mangium. Thus, the information of strength properties of species is acquired from strength property's test at green and air-dry conditions. The required information namely, bending parallel to grain, compression stress parallel to grain, shear parallel to grain and modulus of elasticity. The ultimate stresses obtained from strength properties of the species is to be converted into basic and grade stresses to determine the strength group of the species based on MS 544: Part 2 (2001). The results from the study indicated that, Acacia mangium classified under strength group SG5, whilst Aras was classified under strength group SG7. The timber is classified as medium density of Light Hardwood ranging from 0.37-0.52 g/cm3 at air-dry condition.
Air Flow Analysis in Square Duct Bend
Authors: Musa Mohamad Nor , Mukhtar Mohd Nurul Hafiz
Published: November 2014

This paper present new result for experimental analysis of air flow velocity and pressure distributions between two ducts bend: (1) 90° duct bend with a single turning vane having 0.03m radius and (2) 90° duct bend with double turning vane, in 0.06 × 0.06 m duct cross section. The experiment used five different Reynolds numbers chosen between the ranges 1 ×104 and 6×104. Each experiment has four point measurements: (1) point 1 and point 2 at cross section A-A and (2) point 3 and point 4 at cross section B-B. The first experimental study used single turning vane radius 0.03m with inlet air velocity from 2.5m/s to 12.2m/s. And for the second experiment that used square turning vane with 0.03m radius. In experiment 2, the inlet air velocity also start from 2.5m/s to 12.2m/s. From analysis results, the pressure drop in experiment 1 is higher than experiment 2. As example the maximum pressure drop at 7.5m/s inlet air velocity between point 1 and 3 was found to be 71.6203 Pa in experiment 1 as compared to 61.8093 Pa in experiment 2. The velocity after duct bend is greater when using double turning vane compare used single turning vane as maximum velocity at point 3 in experiment 2 compare to velocity at point 3 in experiment 1 that is 55.677× 10-4 m/s and 54.221× 10-4 m/s. The velocity at duct wall is equal to zero. When increase the value of Reynolds number or inlet velocity, the maximum velocity and total pressure also increase. For example in experiment 1 at point 1, the velocity is 48.785 × 10-4 m/s at Reynolds number 1 ×104 and velocity 65.115×10-4 m/s at Reynolds number 12.2 ×104 . Velocity flow in duct section are lower than inlet velocity. In experiment 1, the inlet velocity is 2.5m/s meanwhile the maximum velocity in the duct section at point 2 is 73.075×10-4 m/s that is much more lower than inlet velocity.
FE Modeling and Analysis of Structural Adhesive T-Joint at Elevated Temperature
Authors: Izzawati Basirom , Afendi Mohd , Nurhashima S. , Nor A. , Abdullah A.R. , Daud R.
Published: November 2014

Adhesive bonding is a joining technique that offers great design flexibility as it can be effectively integrated into practically available industrial sequences of single-piece work. Adhesive is seldom used in high-temperature structural applications that exposed to extreme environment, particularly in the granulation application. Granulator fluidization bed is a main component of urea granulator system in fertilizer plant. Perforated plate and frame structure are normally joined together using plug welding techniques. However, this technique has been proven unreliable. Plug welding technique requires specific amount of heat and welding speed to avoid excessive metal melting (304L Stainless Steel) due to a thin perforated plate, i.e. 1.25 mm. Moreover, fluidization bed is exposed to operating temperature of 95°C. This research aims to examine adhesively-bonded T-joints in tension at temperatures between room temperature and 100°C. This is also to identify the effective bond thickness at different temperatures by testing specimens with various bond thicknesses. The experimental result obtained used for validation by FE model of adhesive T-joint.
High Pressure Cold Spray (HPCS) Process as Coating Treatment for Magnesium Chassis: An Overview
Authors: Nooririnah Omar , Muhamad Azwar Azhari , Mohamed Suhana , Sham Rohana , Raja Mohd Rasi Raja Zuraidah , Yusuf Yusliza , Azlan Umar Al Amani , Amir Burhanuddin Zubaidah
Published: November 2014

Magnesium,Mg and its alloys have excellent physical and mechanical properties for a number of applications. Mg approximately 35% lighter than aluminum and has exceptional stiffness and damping capacity. Disadvantage of this metal and its alloys are highly susceptible to corrosion, particularly in salt-spray conditions and very susceptible to surface damage due to impact. This paper is an outcome of project to address corrosion problem at Mg chasis part in walkie talkie radio using cold spray technique. Current practise of corrosion treatment for Mg chassis structure is using organic coating contains no heavy metals, fluorides with no effect on the alloy composition upon recycling. Disadvantage of this technique is galvanic corrosion at Mg chassis part after 48hrs of salt spray testing and dull finishing. There is keen interest to explore potential applications of high pressure cold spray (HPCS) process onto Mg structure for corrosion treatment. One of the characteristic of cold spray process is creates a negligible heat-affected zone in the as-deposited material and substrate, therefore generating layers that exhibit excellent fatigue characteristics and spray efficiency in HPCS reaching up to 90%. Due to this features, cold spray is potential solution for corrosion treatment to be applied on Mg chassis structure.
Influence of Mortar Incorporating Silica Based Waste Material on the Formation of C-S-H and Mechanical Strength Properties
Authors: Tamanna Nafisa , Sutan Norsuzailina Mohamed , Yakub Ibrahim , Lee Delsye Teo Ching , Ahmad Ezzaq Farhan
Published: November 2014

Recent studies have been carried out to utilize waste glass in construction as partial cement replacement. This paper investigates the formation of Calcium Silicate Hydrate (C-S-H) and strength characteristics of mortar in which cement is partially replaced with glass powder by replacement level of 10%, 20% and 30%. Mortar cubes containing varying particle sizes in the ranges of 150-75μm, 63-38 μm and lower than 38 μm and in a water to cement ratio of 0.45 and 0.40 have been prepared. Replacement by 10% cement with glass powder reveals high compressive strength and produces more C-S-H at 28 days than other levels of replacement.
Determine Aerodynamic Characteristics for FX63-137 Aerofoil by Using Subsonic Wind Tunnel
Authors: M. Saad Magedi Moh , Asmuin Norzelawati
Published: November 2014

This paper is primarily concentrated with determining aerodynamic characteristics and choosing the best angle of attack at a maximum lift and low drag for the FX 63-137 aerofoil at a low Reynolds number and a speed of 20m/s and 30m/s, by using subsonic wind tunnel through manufacturing the aerofoil by aluminum alloy using a CNC machine. The proposed methodology is divided into several stages. Firstly, manufacturing the aerofoil using an aluminum alloy. Secondly, the testing process is carried out using subsonic wind tunnel. Thirdly, the results are displayed and compared with results produced from related works, in order to find out the best angle of attack at a maximum lift.
Design Parameter to Develop Secondary Flow in Twin Screw Extruder
Authors: Salahudeen Shafaat Ahmed , Rahmat Abdul Razak
Published: November 2014

Possibility of generating strong secondary flow in mixing region of twin screw extruder was analyzed numerical FEM simulation using the commercial CFD package Polyflow. Adaptive remeshing - mesh superposition technique was used to generate high density polyethylene velocity profiles in simulation. Clearance between barrel wall and mixing element was increased gradually and observed the changes in flow pattern. Mixing element tip radius was varied by ratio to generate convergence flow in the clearance region and visualize the strength of secondary flow profile. Strong secondary flow at the clearance channel can generates elongation flow and improves the dispersive mixing; helps to decrease the screw length by minimizing kneading disc number in mixing section.
Specific Properties of Novel Two-Dimensional Square Honeycomb Composite Structures
Authors: Mat Rejab Mohd Ruzaimi , Hassan W.A.W. , Siregar Januar Parlaungan , Bachtiar Dandi
Published: November 2014

Hexagonal honeycomb cores have found extensive applications particularly in the aerospace and naval industries. In view of the recent interest in novel strong and lightweight core architectures, square honeycomb cores were manufactured and tested under uniform lateral compression. A slotting technique has been used to manufacture the square honeycomb cores based on three different materials; glass fibre-reinforced plastic (GFRP), carbon fibre-reinforced plastic (CFRP) and self-reinforced polypropylene (SRPP). As semi-rigid polyvinyl chloride (PVC) foam was placed in each of unit cells to further stiffen the core structure. The core then was bonded to two skins to form a sandwich structure. The compressive responses of the sandwich structures were measured as a function of relative density. In this paper, particular focus is placed on examining the compression strength and energy absorption characteristics of the square honeycombs with and without the additional foam core. Comparisons in terms of specific strength and specific energy absorption have shown that the CFRP core offers excellent properties. The presence of the foam core significantly increases the energy absorption capability of overall structure and the SRPP core could potentially be used as an alternative lightweight core material in recyclable sandwich structures.
Evaluation of Palm Stearin as Shaft Lubricant
Authors: Sapawe N. , Syahrullail Samion , Idris M.F.
Published: November 2014

The shaft is very important which have been used to transmit the power. Over a longer period, shaft may be worn. Hence to reduce the worn effect, the shaft must be lubricated. Nowadays, Malaysia is being one of the biggest producers and exporters of palm oil product. Thus, by using this advantage, Palm Stearin which is solid fraction obtained by the fractionation of palm oil after crystallization is being used as a shaft lubricant. This research has been conducted to determine the frictional force of rotational shaft and to observe the wear and surface roughness. The experiment is conducted within 20 mins for each speed which are variance from 200 rpm to 1200 rpm with increment by 200 rpm by using modified pin on disc machine. Based on the result, Palm Stearin show the good performance which is has the lower frictional force compare with two others industrial lubricants. Besides that, surface roughness and wear of shaft did show any significance difference for before and after the experiments. It can be conclude that the Palm Stearin has the lower frictional force which is in the range from 2 N to 4.1 N.
Aerodynamic Analysis on Proton Inspira by Simulation
Authors: Nor Musa Mohamad , Mohamad Zainol Mohammad Zul Zamanhuri
Published: November 2014

The purpose of this project is to study the airflow from across Proton Inspira car and evaluate the drag force and drag coefficient of the Proton Inspira car by simulation. All relevant data are collected through the literature review from book and journal. In methodology, model specification and simulation procedure is explained, together with consider assumption. Five selected speed were been input to the software to determine the CD Value. The calculation and graphical result has been generated by the software and discussed.
Mechanical Properties of Hybrid Thermosets from Vinyl Ester Resin and Acrylated Epoxidized Palm Oil (AEPO)
Authors: Fakhari Alireza , Rahmat Abdul Razak , Wahit Mat Uzir , Mustapha Siti Noor Hidayah , Wan Tajulruddin Wan Nurhayati
Published: November 2014

A series of green hybrid thermosetting resins composed of acrylated epoxidized palm oil (AEPO) and vinyl ester (VE) were prepared via free radical polymerization. The AEPO/VE ratio was varied between 5/95 and 20/80 wt.%. The mechanical properties of resulting hybrid systems were investigated by tensile and flexural tests. The results revealed that these hybrids exhibit mechanical properties comparable to those of commercial vinyl ester resins.
Design Optimization of Single-Phase Outer-Rotor 8S-8P Hybrid Excitation Flux Switching Motor for Electric Vehicle
Authors: Mazlan Mohamed Mubin Aizat , Sulaiman Erwan , Ahmad Md Zarafi , Husin Zhafir Aizat , Soomro Hassan Ali
Published: November 2014

Nowadays, in-wheel motors applied in pure electric vehicles (EVs) propulsion systems have attracted great attention in advance research and development. In-wheel direct drive provides quick torque response, higher efficiency, weight reduction, and increased vehicle space. As one of alternative, a new design of outer-rotor hybrid excitation flux switching motor (ORHEFSM) for in-wheel drive EV is proposed. In this paper, the optimization design of single-phase 8S-8P outer rotor HEFSM is analysed. Open and close circuit of initial and final design is compared based on 2-D finite element analysis (FEA). The design optimization has been made on the initial design machine shows that there is great enhancement on torque and power.
Optimization of 6S-14P E-Core Hybrid Excitation Flux Switching Motor for Hybrid Electric Vehicle
Authors: Zakaria Siti Nur Umira , Sulaiman Erwan
Published: November 2014

Research on hybrid electric vehicle (HEV) which combined battery based electric motor and conventional internal combustion engine (ICE) have been intensively increased since the last decade due to their promising solution that can reduce global warming. Some examples of electric motors designed for HEV propulsion system at present are dc motor, induction motor (IM), interior permanent magnet synchronous motor (IPMSM) and switched reluctance motor (SRM). Although IPMSMs are considered to be one of the successful electric motor used in HEVs, several limitations such as distributed armature windings, un-control permanent magnet (PM) flux and higher rotor mechanical stress should be resolved. In this paper, design improvement of E-Core hybrid excitation flux switching motor (HEFSM) for hybrid electric vehicles (HEVs) applications are presented. With concentrated armature and field excitation coil (FEC) windings, variable flux capability and robust rotor structure, performances of initial and improved 6S-14PE-Core HEFSM are analyzed. The improved topology has achieved highest torque and power of 246.557Nm and 187.302 kW, respectively.
Performance Comparison and Analysis of (HEFSM) and (FEFSM) Using Segmental Rotor Structure
Authors: Soomro Hassan Ali , Sulaiman Erwan , Omar Mohd Fairoz
Published: November 2014

This paper presents a new structure of hybrid excitation flux switching motor (HEFSM) using segmental rotor and the comparison of HEFSM and FEFSM using segmental rotor is performed to find the best candidate for hybrid electric vehicles (HEV). (HEFSM) using segmental rotor contains both the FEC and PM on the stator to produce maximum flux linkages. Initially, the coil arrangement tests are examined to validate the operating principle of the (HEFSM) using segmental rotor. Moreover the profile of flux linkage, cogging torque, and torque characteristics at various armature current densities of both the (HEFSM) and (FEFSM) using segmental rotor are observed based on 2D-finite element analysis (FEA). Initially performances show that HEFSM using segmental rotor produces torque of 18 Nm with low cogging torque and sinusoidal flux waveform. Thus by further design optimization the proposed motor will effectively achieve the target performances.
An Overview of Waste-to-Energy in Malaysia
Authors: Sadeghi Omidreza , Fazeli Alireza , Bakhtiarinejad Marjan , Che Sidik Nor Azwadi
Published: November 2014

Inevitably, energy plays a vital role on our social life and fossil fuel forms of energy meet the most part of our energy demand. Fossil fuels are exhaustible whereas global energy demand is increasing. Furthermore, they pose significant and principal adverse impacts on environment and public health. As a consequence, societies are seeking alternatives to substitute the fossil fuel consumption. The issue of utilizing agriculture waste to produce energy has always been the matter of debate for the societies.
Potential Surplus of Rice Straw as a Source of Energy for Rural Communities in Indonesia
Authors: Anshar Muhammad , Ani Farid Nasir , Kader Ab Saman
Published: November 2014

This study was conducted to identify the potential surplus of rice straw as a source of energy for rural communities in Indonesia. Rural communities need a source of energy for electrical energy and small industry. Determination of the potential surplus of rice straw performed by compared the total potential of rice straw produced and portion used for other usage such as animal feed and raw materials for industry. The remainder wasted was named as a potential surplus of rice straw in this study that can be used as fuel. The study shows the potential of rice straw in total, for animal feed, for industries raw materials, and for energy source. Each of which has increased average about 2% per year or increased about 10% over 5 years (2009-2013). The study is expected to be one of the alternative sources of energy to meet the electrical energy needs and energy requirements for small industries on rural communities in Indonesia.
Assessment of Subsurface Profile at SILC, Nusajaya by 2D Resistivity Method
Authors: Mohd Akip Tan Siti Norsalkini , Mohamad Edy Tonnizam , Saad Rosli , Nordiana Mustaza M.
Published: November 2014

An assessment of subsurface profile of a study area at Nusajaya. Johor was conducted using 2D resistivity method. The aims of the study are to determine the subsurface profile hence contouring the appearance of outcrop by 2D resistivity imaging. Subsurface structure can be delineated based on the physical and chemical parameter which is apparent resistivity of the medium. A survey line of 80m and minimum 2m electrode spacing was adopted using Pole-dipole array. Data acquisition on the survey line was completed and processed by using Res2Dinv software. The inversion model resistivity shows sandstone contains iron mineral (30-250 ohm-m) and weathered sandstone (500-1000 ohm-m). The lower part of the layer represents sandstone and siltstone exhibit high resistivity values of 1500-5000 ohm-m. The range from 30-1000 ohm-m correspond to the grade IV and V of sandstone in the actual profile. Meanwhile, the high range of the resistivity value matched the material with weathering grade II and III in ground mass. The deterioration of most physical properties was associated with the increase number of weathering grade.
Design and Implementation of Shift Frequency Measurement System for Metal Detector
Authors: Win Yin Thu , Moe Aung Lwin , Thet Aung Ko Ko
Published: November 2014

Metal detectors are widely used to find embedded metal within objects which are beyond eye site. This study concerns the design and implementation of frequency counter with 4 digits seven segment LED display for metal detection system using PIC microcontroller. New algorithm for frequency counting is developed. The software is also developed to detect the shift frequency measurement from the VCO output. The corresponding frequency at the VCO output of Induction Balance Metal detector is clarified. The experimental results of this research revealed that using PIC16F628A for frequency measurement system is able to provide very high accuracy for metal detection application. Additionally, the proposed system is the cost effective, less circuitry, high performance control system and feasible for many other metal detection applications.
Effect of Different CaF2 Powder on Micromechanism and Dissolution Rates of CaF2 Block
Authors: Wang Pan , Ma Xiang , Kang Le , Zhang Cheng , Nian Hong Qiang
Published: November 2014

CaF2could be used as inner protection liner material of the cavity which is chemical etched by H2O and HF. This is because CaF2is not easy deliquescence, corrosion resistance and self-lubricating properties. This paper mainly analysis and research the three kinds of powder form different manufacture factory. The powder is burned in the air at 1360°C for 0.5h, the result display that the density of block we get after a powder is burned is the biggest and the width of the peak gets narrow after were calcined, which indicates the crystallinity has improved. The powder did not react with water at 90°C,but the powder was burned react with water at 90°C。
Theoretical Studies on an Energetic Material: Di-s-Tetrazine Derivatives
Authors: Zhou Hua , Ma Zhong Liang , Guo Jia Hu , Wang Jian Long
Published: November 2014

Computations by density functional theory (DFT) method were performed on a series of di-s-tetrazine derivatives with different substituents and linkages. The heat of formation (HOF) was predicted by designed isodesmic reaction. The results illustrated that introductions group –N3or –N=N– could augment the HOF extremely. The crystal structures were obtained by molecular mechanics methods with dreiding force field. Detonation performance was evaluated by using the Kamlet-Jacobs based on the calculated density and HOF. It was found that –ONO2, –NF2, –NH–NH– and –N=N– groups were effective to enhance the detonation performance of these derivatives. Seven compounds were screened as the potential candidates for high energy density materials.
The Study of NO2 Gas Sensor Based on NASICON
Authors: Xie Bing Xing , Xu Yi Wei , Sun Jiang , Jiang Dan Yu , Feng Tao
Published: November 2014

NASICON materials can be used as the solid electrolyte component in the sensor system, because they have excellent Na+ conductivity. This study prepares NASICON materials by solid state reaction method, and their phase, microstructure and electrical property will be characterized by XRD, SEM and EIS. Then an amperometric NO2 sensor is fabricated to detect NO2 gas in the level of ppb. The sensor current signal will be studied by changing different NO2 concentrations, employing different materials on the counter electrode and using different applied voltages when the working temperature is 150°C.
Impact of Domain Wall Pinning on the Dielectric Loss of Relaxor Ferroelectrics
Authors: Li Li Ben , Li Guo Ling , Zhou Ya Peng , Zang Guo Zhong
Published: November 2014

Charge density wave theory is used to investigate the dependence of dielectric loss of relaxor ferroelectrics on temperature, frequency and concentration of impurities. The dielectric loss originates from the local pinning. The competition between the local and collective pinning leads to a peak in the curve of dielectric loss v.s. temperature as well as the curve of dielectric constant v.s. temperature. The peak temperature of dielectric constant TL, increases with increasing frequency and with decreasing concentration of impurities. The maximum dielectric loss is in proportion to TL and in inverse proportion to the barrier height. Our theoretical results agree qualitatively with the experimental results.
Optical Diagnosis of Atmospheric Pressure Gas-Liquid Diffuse Discharge Excited by Nanosecond Pulse Voltage
Authors: Wei Ya Bo , Zhang Li , Jiang Peng Chao , Zhang Shuai , Yang De Zheng
Published: November 2014

In this paper, A bipolar high voltage pulse with 20 ns rising time was employed to generate diffuse gas-liquid diffuse discharge in helium, and dielectric-free electrode configuration is used to generate room temperature plasma in small gas flow rate, which can be considered as a effective method to reduce the production cost. Discharge images, waveforms of pulse voltage and discharge current, and emission spectra of active species are measured.
Structure and Optical Properties of ZnO:N Films Doped with Nitrogen Atoms
Authors: Zhao Yue , Ding Yan Li , Liang Xiao Yan , Min Jia Hua , Wang Lin Jun , Shi Wei Min
Published: November 2014

s: In this study, nitrogen-doped ZnO thin films with different nitrogen content were produced by a wet chemical process. The optical properties and the structure of these ZnO films were investigated by LT-PL spectrum, Raman spectrum, SEM and XRD. XRD result showed that the cubic ZnO phase appeared in the 10% nitrogen-doped ZnO films, which might be attributed to the stress in these ZnO film. Moreover, results of SEM measurement proved that the nitrogen atoms were introduced into the lattice of nanoZnO crystal. In addition, LT-PL spectra also confirmed that this new appeared phase was a cubic ZnO phase, due to the lack of the new PL mission peak. Key words: ZnO, wet chemical method, luminescence, XRD
Electrical and Optical Stability of Two Kinds of Different Element Doped Tin Oxide Film Carrier Materials in an Acid Environment
Authors: Shi Xiao Li , Jiang Ye Hua , Zhang Yu Qin , Wu Hui Jun
Published: November 2014

The stability of the fluorine doped tin oxide (FTO) and the indium doped tin oxide (ITO) films, which are used as gene chip carrier, are detected in an acid solution. The change of relative resistivity (Δ R/R) with immersion time and average visible light transmittance of the films are contrasted before and after immersing in 1 mol/L (1M) H2SO4 solution. The results indicate that the Δ R/R of ITO film sample increases rapidly with increasing the immersion time, and Δ R/R is 111% after 12 h;However, the Δ R/R of FTO film sample increases smoothly and the Δ R/R is 2.9% after 100 h immersion. At the same time, the average visible light transmittance of FTO film decreased, but ITO film is completely corroded, and the average visible light transmittance is close to the glass transmittance. The potentiodynamic polarization curves show that the corrosion current of FTO film is 1.749 × 10−6A and less than ITO,so the corrosion resistance of FTO film is higher than ITO film in 1M H2SO4 solution. Moreover, the corrosion morphology validates this conclusion.
The Influence of Sputtering Power on the Structural, Morphological and Optical Properties of ZnSe Thin Films Deposited by R.F Magnetron Sputtering
Authors: Zheng Yan , Liang Qian , Li Bing , Zeng Guang Gen , Wang Wen Wu , Zhang Jing Quan , Li Wei , Feng Liang Huan
Published: November 2014

By creatively using R.F Magnetic sputtering technique , we have successfully prepared ZnSe polycrystalline thin films on glass substrates..The effect of different sputtering powers on the structural, morphological and optical properties of the as-deposited films were studied. The films were characterized by using X-ray diffraction, UV-VIS spectrometer ,scanning electrical microscope ,etc. The results indicate that :Under the pressure of o.8pa,with the diverse sputtering power varying from 60w to 100w,the intensities of XRD peaks of ZnSe thin films varied apparently ,while the morphological properties were almost the same. It should be noted here that the crystallinity of the ZnSe film, which was deposited with the power of 90W, showed a face-centered cubic phase. Besides, it showed relatively better performance: with strong [111] orientation ,smooth surface without obvious defects, comparatively large band gap and high transmission rate.
The Anti-Oxidation Coatings of Carbon/Carbon Composites
Authors: Li Han , Xu Hong Zhao , Sui Xue Ye , Zhou Chang Ling , Wang Chong Hai , Liu Rui Xiang , Wang Yan Yan
Published: November 2014

C/C composites have excellent properties, but it will be rapidly oxidized when temperature is above 500 °C, which limits its applications in high temperature environment. In order to improve Anti-oxidation, using CVD method, a SiC coating is prepared on the surface of C/C composites. We have studied the microstructure of the SiC coating, oxidation resistance and high temperature mechanical properties. The results show that SiC coating has excellent oxidation resistance. When coated sample is oxidized at 1500 °C after 50 hours, its oxidation weight loss rate is only 1.45%, and coated samples can still maintain high mechanical properties at 1200 °C.
Study on High Temperature Coating of Cf/SiC Composites
Authors: Wang Yan Yan , Zhou Chang Ling , Wang Chong Hai , Liu Rui Xiang , Jiang Kai
Published: November 2014

Cf/SiC composite are widely used in aerospace, chemical industry, traffic, and many other fields because of good mechanical properties, heat resistance, thermal shock resistance and abrasion resistance, corrosion resistance, etc. But its oxidation resistance is poor in the application of high temperature environment. In this paper, high-temperature ceramic coating was prepared on Cf/SiC composites surface through brush painting method and the oxidation resistance of the coating were studied. The coating was tested by XRD, SEM, etc. The results showed that the coating and composite matrix is good combination, at the same time the coating has good oxidation resistance.
Preparation of YAM Coating on the ZrB2 Composites Ceramics by Co-Precipitation Process
Authors: Li Shi Bin , Ru Hong Ying , Song Jie Guang , Bai Xiao Bo
Published: November 2014

. Zirconium diboride (ZrB2) acts as an ultra-high-temperature ceramics, and are applied in over 2000°C environment. With the characterization of strong covalent bonding structure and high melting point, it is difficult to realize sintering. For achieving composites system densification, the transition metals with good wettability and other matching properties, or the second phases ceramics were added as sintering aids, but the bulk materials' application temperature limit and ablating rate resistance were reduced by sintering aids. Among the A12O3-Y2O3 binary phase system, YAM(Y4A12O9) has the highest melting point, chemical and physical compatibility is matched with ZrB2 composites. The YAM coating was prepared on bulk materials surface by co-precipitation routine, the effects of precursor volume fractions and calcining process on coating phases were investigated, and the coating morphology and interface bonding were observed. The aim is to obtain the best protective coating constituents and technology parameters.
Plasma Sprayed 4-Phase Ceramic Abradable Seal Coatings and their Thermal Shock Resistance on Nickel-Based Superalloy
Authors: Gao Jun Guo , Lu Feng , Guo Meng Qiu
Published: November 2014

Novel 4-phase ceramic abradable seal coatings have been prepared by plasma spray. The as-prepared coatings were characterized by SEM, EDS and XRD. The results showed that the 4-phase ceramic abradable coating exhibited porous structures and had good adhesion with the bond coat. The ZrO2 and Al2O3 in the coating existed in the form of tetragonal-ZrO2 and α-Al2O3, respectively. The result of thermal shock test revealed that compared with the 3-phase abradable coating, the thermal shock life of the 4-phase abradable coating had increased tenfold to 1900~2000 cycles from 100~200 cycles. The reason is owing to the reduction of oxygen partial pressure and thermal stresses at the top/bond coat interface due to the addition of the fourth nanoAl2O3 phase.
Preparation and Properties of Organic Silicon Atomic-Oxygen-Protection Film
Authors: Li Cun Hui , Zheng Kuo Hai , Yang Sheng Sheng , Li Zhong Hua , Tang Dao Tan
Published: November 2014

Materials used on exterior spacecraft surfaces are subjected to many environmental threats which can cause degradation, atomic oxygen is one of the most threats. We prepared organic silicon atomic-oxygen-protection film using method of polymerization. This paper presented the effects on the film structure and its durability of the preparation processing, and analyzed the polymerization theory, the film structure and composition of the film. At last, we tested the film in our ground based atomic oxygen simulator, and indicated that the film worked well.
Effect of Solid Reaction Temperature on the Cation Mixing and Electrochemical Properties of LiNi0.4Co0.2Mn0.4O2 Catode Materials in High Energy Li-Ion Batteries
Authors: Zhang Lin , Luo Fei , Zhang Xing Shuai , Guo Yu Zhong
Published: November 2014

A LiNi0.4Co0.2Mn0.4O2material was prepared via the co-precipitation in solution and ensuing solid reaction of the prepared precursors with LiOH.H2O, investigating the influence of solid reaction temperature on the cation mixing and electrochemical performance of the materials as a cathode. The results show that Li+/Ni2+cation mixing decreases with the increase of calcination temperature in the range of 700-900°C, and the lower degree of cation mixing can improve 2D layered structure and make the material more stable. The discharge capacity and the capacity retention rate of the material is strongly impacted by the reaction temperature.The powders calcined at 900°C show the best electrochemical performance and the initial discharge capacity is 163.1mA·h/g, after 40 cycles, the capacity retention rate is 93.9%.
Inhibitive Effect of a New Dental Resin Composite on Enamel Artificial Caries
Authors: Zhao Xin Yi , Hou Shao Jie , Li Shi Bao
Published: November 2014

Purpose To investigate the cariostatic effect of six restorative materials in vitro. Method Enamel blocks of bovine incisors were restored with six restorative materials (a conventional GIC, FujiIILC, Compoglass F, BeautifilII,Charisma and an experimental fluoride releasing resin composite) respectively with a gap of 270μm in width between each filling material and enamel. Then all restorations were immersed in a partially saturated acidic buffer solution at 37C for 3days. The surface enamel microhardness of the enamel blocks were measured before and after demineralization and the depth of enamel demineralization was measured using polarization microscope for each restoration.Results Enamel surface hardness of all restorations demonstrated significant reduced after demineralization ( p<0.05), and the order of hardness reduction is as follows: Charisma >BeautifilII≈Compoglass F≈Experimental Resin>FujiIILC>GIC ( p> 0.05). The order of the depth of enamel demineralization along the surface and the interface near the gap for the 5 materials is as follows: Charisma >BeautifilII≈Compoglass F ≈Experimental Resin>FujiIILC>GIC (P > 0.05). Conclusion The new fluoride releasing and recharging composite resin has the ability to prevent recurrent caries around the restoration and its ability is comparable to compomer materials.
Synthesis and Characterization of GdO+ Nanosheets Doped with Tm
Authors: Zhang Yan Yan , Sun Shi Liang , Zhou Guo Liang , Jiang Dan Yu , Feng Tao , Shi Wang Yan , Li Qiang
Published: November 2014

Tm doped GdOBr compounds were successfully synthesized through solid-state method. Then bromide ion in the as-synthesized compounds Gd0.97Tm0.03OBr was exchanged by P-toluene sulfonate ion in P-toluene sulfonate sodium solution. A sol-solution was obtained after the ultrasound treatment of intercalating sample in formamide solution. In addition, many rare-earth metal elements can launch visible light when excited. The emissions of Tm3+ at 478nm originated from the transition of Tm3+(1G4→3H6) was observed.
Preparing Superfine Quartz Sand Powder by Ball Milling Method
Authors: Ma Bo Feng , Tan Bin , Zhao Wen Bo , Liang Xin , Hu Fa Mei , Yang Guo Sheng , You Liang Liang , Wang Ruo Lan , Liu Hong Ying , Song Jie Guang , Wang Fang , Liu Rong Jin
Published: November 2014

To save land resources by the use of low-grade natural resources to realize a high cost performance product, the technology of prepared superfine quartz sand powder via the ball milling methods were investigated. The results are shown the mean particle size of quartz sand powder is gradually become small varied with prolonging the ball milling time. Before 60 minutes, the mean particle size is slashed, however, the range of varying mean particle size is less after 60 minutes under the ball milling rotate speed for 200r/min and the charge amount for 200g/L, so the ball milling time for 60 minutes is decided.The mean grain size of quartz powders are decreased vary with an increasing the ball milling rotate speed, and the rotate speed is lower, the distribution is wider, however, the rotate speed is higher, the distribution is narrower.The mean grain size of quartz powders are 11.25μm via a roller ball milling, the mean grain size of quartz powders are 7.37μm via a planetary ball milling, and the particle size distribution of quartz powders milled via a roller ball milling is wider than that of quartz powders milled via a planetary ball milling, which shows the of quartz powders milled via a roller ball milling is not more uniform than that of quartz powders milled via a planetary ball milling, the asymmetry powder is advantage for forming the high performance building materials body.
Solvothermal Synthesis of Carbon-Coated Nickel Nanoparticles in Ionic Liquid
Authors: Li Fu Yu , Xu Cun Ying , Yang Ying Ya , Hua Yi Xin , Li Jian
Published: November 2014

Carbon-coated nickel nanoparticles were synthesized by solvothermal method in 1-buty-3-methylimidazolium tetrafluoraborate ionic liquid. The obtained products are characterized by X-ray powder diffraction (XRD), Raman spectroscopy, infrared spectroscopy and transmission electron microscopy (TEM). The magnetic properties of carbon-coated nickel nanoparticles have been investigated by vibrating sample magnetometry (VSM). It was found that the carbon-coated nickel nanoparticles showed excellent magnetic properties. The present route may give researchers more choices for preparing other carbon-coated transition metal nanoparticles.
Low-Temperature Synthesis and Photoluminescence Properties of Wurtzite Three-Dimensional ZnS Nanostructures
Authors: Qi Hong Fang , Li Jun Lang , Shi Ying , Xie Jian Jun , Lei Fang
Published: November 2014

Wurtzite three-dimensional ZnS nanostructure has been synthesised under low temperature (180°C) via solvothermal method in mixed solvents of ethylenediamine and ethylene glycol. The phase structure, morphology and optical properties have been characterized by X-ray (XRD), scanning electron microscope (SEM) and photoluminescence spectra (PL). Through the change of reaction time and the mixed solvent ratio, the properties of three-dimensional ZnS have been discussed in this paper.
Study on the Factors Affecting the Hydrophobic Property of Silica Membranes
Authors: Liu Ya Jun , Wei Qi , Chen Wei Ying , Li Qun Yan
Published: November 2014

Various hydrophobic groups were used to modify the silica membranes by the co-hydrolysis and condensation of 1,2-bis(triethoxysilyl)ethane and alkylsilanes. The hydrophobic property and surface roughness of silica membranes were characterized by water contact angle measurement and atomic force microscope, respectively. The results show that the hydrophobic property of modified silica membranes increases with increasing concentration of alkylsilane in the mixture, increasing surface roughness and increasing length of carbon chain in the alkyl groups.