bluuebunny/crossref_metadata_2025 huggingface dataset:
Qualitative Study on Mechanical Environment Affecting the Degradation of the Magnesium Alloys
Authors: Dong Li Min , Li Xuan , Han Shi Hang , Ye Jin Duo , Ma Yu Chun , Gao Ya Lei , Zhang Chun Qiu
Published: February 2014

Objective Explore the degradation rule of the magnesium alloys in simple mechanical environment. Methods Select a kind of magnesium alloy of better degradation by experiment and prepare screws. The experiment totally contains five groups, they are control group one with no specific conditions, experimental group two with 0.1Mpa external pressure, experimental group three with 0.2Mpa external pressure, pig femoral experimental group four with 0.2N shear force, pig femoral experimental group five with 0.3N shear force. Record the volume of hydrogen every certain time interval and observe the surface morphology of magnesium alloy screws through Object Deformation Image Capture System when the experiment is over to reflect the degradation rate of magnesium alloys. And the experiment would be repeated once to ensure the test results. Results Compared to group one, when external pressure exists, the volume of hydrogen significantly increases. Group two and group three have no significant difference in results, but group three has a greater degree of degradation than group two by observing the surface morphology. The volume of hydrogen of group four and group five is smaller than that of the first group in that smaller volume of screws exposes in SBF. The volume of hydrogen of the fifth group is greater than that of group four. Group five has a greater degree of degradation than the fourth group by observing the surface morphology. The repeated experiment basically keeps the same conditions, but the volume of hydrogen of group three is greater than that of group two.Conclusion Mechanical environment has an impact on the degradation rate of magnesium alloys. The pressure of the environment affects the degradation rate of magnesium alloys. The greater the pressure, the faster the degradation rate. The external force affects degradation rate of magnesium alloys. The greater the shear force, the faster the degradation rate.
Influences of Heat Treatment on A95 Polycrystalline Alumina Fibers Preparation
Authors: Zhang Yong Zhi , Li Hong Xia , Geng Ke Ming , Wu Ai Jun
Published: February 2014

In order to discuss chemical and physical reaction of A95 polycrystalline alumina fibers (PAF) during heat treatment and improve the properties, the influences of the protective atmosphere and heat treatment temperature on properties of PAF were researched. DT-TG, IR, XRD and SEM were adopted to characterize the fibers. The results show that in N2 atmosphere, the carbonization and oxidation rates of the gel fibers decrease, the thermal decomposition process of the organics is extended and the crystal transformation temperature of alumina is enhanced. When the heat treatment temperature is lower than 1200 °C, the major phases of A95 PAF are mainly δ-Al2O3 and θ-Al2O3, but no α-Al2O3 appears.
The Research of SVPWM Control of Shunt Active Power Filter Based on the Inner Relationship between Current and Voltage
Authors: Zhang Meng Hua , Cheng Xin Gong , Zong Xi Ju
Published: February 2014

To achieve the goal of decreasing the harmonic level in the power grid, traditional shunt active power filter uses the methods such as triangular wave comparison and hysteresis comparator which overall exist some problems, for instance, poor ability of current tracking and low efficiency of DC voltage utilization that lead to bad compensation result. Therefore, we put forward another SVPWM based control strategy in which a relationship between the current reference instruction of active power filter and the voltage reference instruction of SVPWM is found via the topological structure of shunt active power filter. Then we can use SVPWM method to accurately track and compensate the harmonic current. Simulation and experimental results show that the control strategy can solve the above proposed problems and bring about very good harmonic compensation effect.
Study on Control System and Precision Positioning Table Identification Technology of Universal Joint Performance Testing Table
Authors: Chen Jia Bao , Shi Lun , Qin Xu Qi
Published: February 2014

A comprehensive performance testing table of the constant velocity joint drive shaft assembly is discussed in this paper. This testing table is able to operate 9 testing items. The mechanical structure, the working principle, and the software system of the testing table is introduced respectively. Intelligent measuring method and LCOD technique is used in the system. System identification method is applied while designing the control system. An example of slip curve testing program is also given at this paper.
High-Speed CNC Grinding Process Optimization of Non-Circular Rotary Parts Based on Particle Swarm Optimization
Authors: Huang Yu , Ming Wu Yi , Guo Jian Wen , Li Ming Zhen , Li Jian
Published: February 2014

As for the high-speed CNC grinding process for non-circular rotary parts with a large rate of lift change (such as camshaft of automotive engine), the acceleration of grinding wheel often has a direct impact on the contour grinding precision of the workpiece due to the large acceleration of movement between of the workpiece and the grinding wheel produced from CNC grinding interpolation. Researches show that solving this problem is an important way to improve the precision of high-speed CNC grinding for non-circular rotary parts. In this paper, a high-speed CNC grinding process control and optimization method is presented for non-circular rotary parts based on acceleration interpolation movement. The negative inﬂuence of the problem about high acceleration can be reduced eﬀectively and the precision of high-speed CNC grinding for non-circular rotary parts can be improved greatly by the proposed method. Additionally, the simulation shows that the optimization of grinding parameters forgrinding process has a good performance.
Preparation and the PL Properties of Er3+ - Ce3+ Co-Doped TiO2 Powders
Authors: Bai Ling Yun , Jiang Long Fa , Xiang Jun Huai
Published: February 2014

The 0.5-3.0 mol% Er3+-Ce3+ co-doped TiO2 powders have been prepared by sintering the hybrid materials Er0.5Ce0.5(AA)3phen-doped TiO2/PMMA, which were prepared by sol-gel method, using the modified titanium (IV) n-butoxide [Ti(O-Bu)4-x(AAPhen)x] as precursors which were given by the chelate reaction between Ti(O-Bu)4, AA and Phen at 70°C. The hybrid matrix TiO2/PMMA improved the dispersion of Er3+, which caused an enhancement in the photoluminescence (PL) peak intensity at 1.53 mm of the 1 mol% Er (AA)3phen-doped TiO2/PMMA powders sintered at 700 °C of about 23 times higher than that only had TiO2 as its matrix. When co-doped with Ce3+, the above ratio of the PL peak intensity was raised to 75 times, which illustrated the obvious sensitization and dispersion effects of Ce3+ on Er3+.
Force Analysis for Working Unit of Mini Tracked Truck
Authors: Wang Zhi Qiang , Bian Xue Liang , Bian Chun Yan , Du Feng Bo
Published: February 2014

Mini tracked truck’s working unit is a device constrained by the dual parallelogram. This unit can make the goods remain translational during the process of loading and unloading so as to ensure the work process safe and reliable. Because the device is consisting of two parallelograms in series and using the rail to constrain its trajectory, the institutional force is very complicated. Therefore, this article uses statics method to analyze the force that acts on the working unit, establish the mechanical equations of the main arm cylinder and the lifting arm cylinder. The article respectively gives the simulation of the mechanical properties of the main arm cylinder during the loading process and the lifting arm cylinder during the lifting process basing on MATLAB. Research result provides a theoretical basis for the design of this type of working unit.
Optimization Design on Covering-Soil Machine for Grape Vines
Authors: Huo Shi Wu , Zhao Feng Qin
Published: February 2014

Aiming at the problem of the fracture and damage of key parts of covering-soil machine for grape vines, on the basis of structure design and test study of the existing small covering-soil machine for grape vines，its key components were analyzed and optimized by using computer-aided software ANSYS，and the problems of structure design existing covering-soil machine for grape vines were found，in the end, the structure of the machine with high-performance was attained through optimizing. This study can provide theoretical basis for this kinds of machine production.
Influence of High Temperature Processing on the Substructure of Laser Shock Processed Titanium Alloy
Authors: Hua Yin Qun , Bai Yu Chuan , Ye Yun Xia , Xue Qing , Liu Hai Xia , Chen Rui Fang , Chen Kang Min
Published: February 2014

The paper aims to study the influence of high temperature processing on the substructure of laser shock processed titanium alloy. The titanium alloy specimens were first treated by laser shock processing (LSP), then treated at 700°C for three hours and air cooled to the room temperature to investigate the influence of the high temperature processing. To evaluate such influence, the hardness and substructure on the surface were investigated by micro hardness tester and transmission electron microscope (TEM), respectively. Results show that after three times LSP, the hardness of TC11 alloy was improved by 30.9%. The cause of such an improvement in hardness is that the crystal grains in the surface layer under the shock wave stress were strongly deformed, causing a dynamic recrystallization. The substructure is mainly twin crystals, highly tangled and dense dislocations. After high temperature processing in vacuum, the average hardness is decreased by 12% compared to that of the specimens after LSP. And the substructures are mainly small dislocation, nanocrystalline.
Application of New Photonic Materials in Development of Psychological Disease Intervention Perspective & Diagnosis
Authors: Zhang Gui Lin
Published: February 2014

According to the principle of accurate imaging systems, the accurate new photonic materials equipment is designed. On the basis of establishing the model of Kidney disease to be processed, the new photonic materials equipment is assembled in a virtual manner by using the application software Pro/ Engineer provided by three-dimensional CAD. The virtual image of the components of accurate video equipment is implemented either from top to bottom or reversely, providing a basis for simulation and development of this equipment.
Disc-Electrospun Nano/Macro-Scale PCL Fibers with Nanoporous Structure
Authors: Li Da Wei , Wu Tong , Huang Chen , Ke Qin Fei , Mo Xiu Mei
Published: February 2014

In this study, we fabricated fibers with nanoporous structure via needleless electrospinning with a rotating disc from a ternary system of solvent/nonsolvent/poly (caprolactone) (PCL). PCL was dissolved in a mixture solution of dichloromethane (DCM) and N,N-dimethylformamide (DMF) with a certain ratio. During disc-electrospinning, the volatile DCM would evaporate speedily, cooling down the surface of polymer jets, which condensed the water around. After the evaporation of nonsolvent DMF and water, irregular pores were observed both on the surface and the internal part of the fibers.
Effect of NaOH Concentration and the Addition of NiCl2 on the Preparation of Ni/NiO/C Composite Nanofibers
Authors: Wei Wei , Qian Qing Rong , Xiao Li Ren , Huang Bao Quan , Liu Xin Ping , Xu Jing , Chen Qing Hua
Published: February 2014

Ni/NiO/C composite nanofiber with 60 nm in diameter was prepared by electrospinning and subsequent carbonization. The composition and morphology were characterized by X-ray diffraction and scanning electron microscopy. The electrochemical properties were preliminarily evaluated. It is found that both NaOH concentration and the addition of NiCl2 are key factors for the morphology of composite nanofibers. An electrochemical study reveals that the obtained Ni/NiO/C composite nanofiber exhibits excellent rate capability which makes it promising anode material for Li ion batteries. In addition, our simple and inexpensive stragegy can be further extended to create various functional hybrid nanomaterials.
Composite Nanofibers Containing Microparticles Produced via a Stepped Pyramid-Shaped Spinneret
Authors: Jiang Guo Jun , Zhao Wen Min , Qin Xiao Hong
Published: February 2014

A novel free surface electrospining via a stepped pyramid-shaped spinneret was used to prepare composite nanofibers containing microparticles. We investigate the spinnability of Polyacrylonitrile (PAN) solution containing graphite powder microparticles. The influence of microparticle on fiber diameter has been studied. This method can be used to produce composite nanofibers containing microparticles structures by electrospinning in mass scale.
Theoretical Study on Adsorption and Doping of Pd Atom on Graphene
Authors: Qiao Liang , Hu Xiao Ying , Bi Dong Mei , Zhao Li Jun
Published: February 2014

The adsorption and doping of Pd atom on graphene have been investigated using density-functional theory. The structure, binding energy, Mulliken population, and density of states of Pd-graphene systems are calculated. For the adsorbed graphene, the bridge site is the most favorable adsorption site. The adsorbed and doped Pd atom can stay stably on graphene by donating their charges to graphene, resulting in the charge redistribution of graphene. After the Pd functionalization, the hybridization of states of Pd and C atoms can be observed, indicating strong interaction between them.
Evaluation of the Flexural Properties of Pineapple Reinforced Polymer Composite for Automotive and Electrical Applications
Authors: Ramnath B. Vijaya , Krishna C. Vinodh , Karthik S. , Saravanan K. , Manickavasagam V.M. , Elanchezhian C.
Published: February 2014

The interest in natural fibers has been rising in the past decade due to low cost and abundant availability. Though the composites made from artificial fibers possess superior properties when compared to natural fiber reinforced composites, their high cost makes it unviable in day-to-day applications. This paper is an evaluation of a pineapple fiber reinforced composite using epoxy resin as matrix. Glass fibers are provided as the outer layers to improve the surface finish and strength. Using hand lay-up method, fibers of pineapple are assembled in alternate layers of vertical and horizontal orientation. The flexural properties of the composite are determined. Three samples are tested and it is seen that there is no appreciable variation in the properties. The average break load is 1.29 KN and the deflection is 5.533 mm. The flexural strength is calculated as 78.63MPa.
Simulation Studying on Viscoelasticity and Orthotropic of Composite Materials
Authors: Li Hong , Wang Qing Feng
Published: February 2014

The viscoelasticity and orthotropic of composite materials has been investigated. Based on the essence of dynamic wave equation, a numerical modeling of guided waves propagating in anisotropic viscoelastic plates is developed by employing the spectral finite element method (SFEM). The phase velocity, energy velocity and attenuation curves can be obtained and analyzed by simulating carbon-epoxy film and carbon-epoxy film on the different substrates. The results illustrate that the mode coupling phenomenon will occur due to consider viscoelastic of composite materials which can use for choice of frequency. In the viscoelastic film/substrate system, the more modes and the lower attenuation amplitude appear which explains the better for monitoring long distance. Knowledge of these properties is important for evaluating material damage and designing material structure .
Effects of Milling Techniques and Calcinations Temperature on the Composite Cathode Powder LSCF-SDC Carbonate
Authors: Bakar M.S.A. , Ahmad Sufizar , Rahman Hamimah Abdul , Tasrim M.A.F.M. , Basri H. , Muchtar A.
Published: February 2014

Composite cathode La0.6Sr0.4Co0.2Fe0.8O3-δ-SDC carbonates (LSCF-SDCC) for applications of low temperature solid oxide fuel cell (LTSOFC) were developed. LSCF-SDCC were mixed using high energy ball milling technique via dry and wet milling method followed by calcinations at 700, 750 and 800 °C. The findings reveal that different calcinations temperature and milling techniques gives effects to the composite cathodes powder. Clear peak intensity demonstrate from wet milling technique as confirm via XRD analysis indicates that crystalline structure has been improved. FESEM investigation demonstrate the presence of large particles in the resultant powder resulting from the increased calcination temperature. LSCF-SDCC composite cathodes powder produced via wet milling technique have good fine fraction and demonstrates good crystallite structure to be served as cathode of LTSOFC compared to dry milling technique.
First Principle Study of Hydrazine and OH- Co-Adsorption on Ni(111) in High Coverage System
Authors: Refino Andam Deatama , Agusta Mohammad Kemal , Dipojono Hermawan Kresno , Nugraha Nugraha
Published: February 2014

Theoretical investigation of co-adsorption process between hydrazine (N2H4) and OH- on Ni(111) is performed using density functional theory. OH- adsorption mechanisms at various adsorption sites as well as its interaction with hydrazine in various conformations (anti, cis, and gauche) are studied. The stability of OH- adsorption on nickel surface is significantly influenced by the presence of hydrazine molecule. Among the three conformations of hydrazine, OH- adsorption on nickel surface doesn't occur in cis conformation. Otherwise, co-adsorption occurs in system with gauche and anti conformation. In anti system, hydrazine conformation is transformed during relaxation process and forms gauche conformation as the most stable configuration of the system.
Effect of Strain to the Microstructure and Texture of AZ31 Magnesium Alloy during Compression Deformation at Room Temperature
Authors: Jiang Shan , Zeng Bin , Douadji Lyes
Published: February 2014

AZ31 magnesium alloy samples were compressed to different strains at room temperature and examined through the optical microscope, X-ray diffraction (XRD) and scanning electronic microscope. The results show that the produced twins were mainly the {102} type, and then the {101} type and {102}-{101} type. The size and amount of the twins increased with the strains growth, and after the saturation of twins in the grains the samples fractured. The compressed texture with the basal planes perpendicular to the compression direction also become stronger with strain increase. The {102} twinning deformation played an important role in changing the microstructure and properties of the magnesium alloy at room temperature.
Study on Electrochemical Noise of N80 Steel in NaCl Solution by Wavelet Analysis and Equivalent Circuit Theory
Authors: Zhao Lin , Zhang Yu , Li Bo Wen , Tai Chuang , Li Ji
Published: February 2014

The electrochemical noise (EN) of N80 steel in NaCl solution has been studied by the wavelet and the equivalent circuit theory. Spectrum analysis showed that the corrosion data is no transient peaks, the variations of potential and current showed typical characteristics of uniform corrosion. Wavelet analysis results show that the different time energy fluctuations of different size ranges, low-level occur fluctuations repeatedly and high-level appear concave curve. Analysis shows that it is mainly due to uniform corrosion process, and the control step is diffusion process of corrosive ion. The applications of equivalent circuit analyze electrochemical noise data in theory, and describe the corrosion process by the components of potential noise and current noise power spectral density
Influences of H2SO4 and NaCl Concentrations on Stress Corrosion Cracking of AISI 304 Stainless Steel
Authors: Abd Razak Nur Azhani , Asmara Yuli Panca , Kamaruzaman Mohamad Khairuazlan
Published: February 2014

This paper presents the influence of H2SO4 and NaCl concentrations on the corrosion mode of AISI 304 stainless steel in H2SO4-NaCl aqueous solutions. Immersion test was conducted at room temperature using U-bend specimens. The specimens in annealed and sensitized conditions were immersed in aqueous solutions containing H2SO4 concentration in the range of 0 to 3.0 kmol/m3 with 1.5 kmol/m3 interval, and NaCl concentration in the range of 0.5 to 2.0 kmol/m3 with 0.5 kmol/m3 interval. Results showed that, specimens in sensitized condition have a higher mass loss and higher corrosion rate. In addition, the experimental result also indicates that the two solutes have synergistic effect on corrosion mode of the material that is stress corrosion cracking (SCC) and general corrosion, which occur within a specific range of concentration. SCC region became smaller as the H2SO4 and NaCl concentration increased. However, the occurrence of SCC was high when sensitization treatment was subjected to the specimens. The appearance of surface damage and crack morphology were revealed by using scanning electron microscopy (SEM).
The Static Recrystallization Behavior of Fe-Mn-Si-Al Series TWIP Steel
Authors: Wu Yan Xin , Tang Di , Mi Zhen Li , Jiang Hai Tao
Published: February 2014

he softening and static recrystallization behavior of typical Fe-Mn-Si-Al series TWIP steel between high temperature deformation passes was investigated by two-pass hot compress deformation experiments on Gleeble-3500 thermal simulated test machine. The dynamic model of static recrystallization was built according to the experimental results. The investigation of the effects of deformation temperature, deformation rate and pre-deformation shows that deformation rate is the most effective parameter, and the increase of deformation and pre-deformation can also promote the static recrystallization. The calculated static recrystallization activation energy of TWIP steel is about 147kJ/mol through the dynamic equation built. The results of model predict conform to the experimental results.
Microstructure and Plastic Deformation Behavior of Modified AA7075-T6 Aluminum Alloy
Authors: Kim Kyu Sik , Kim Gwan Yeung , Sung Si Young , Han Beom Suck , Kwon Yong Nam , Lee Kee Ahn
Published: February 2014

This study investigated the plastic deformation behavior and microstructure evolution of the modified AA7075 alloy (using Eco-Mg in lieu of Mg element). Before the compression tests, the microstructure was observed and phase analysis was performed. As the conditions for the compression tests, temperature range was from 523K to 723K and strain rates were controlled from 10-2 s-1 to 10 s-1 using Gleeble equipment. The flow stress of the modified AA7075 alloy with their small grain size and second phases were slightly higher than that of conventional AA7075 alloy. The activation energy for the plastic deformation of this alloy was about 135.9kJ/mol, a relatively lower value compared with the conventional AA7075 alloy (more than 140kJ/mol). The processing map of the modified AA7075-T6 alloy was plotted and compared with that of conventional alloys. This alloy showed similar formability with the conventional AA7075 alloy, i.e., similar area of stable deformation region. We also attempted to discuss plastic deformation behavior related to its microstructure.
An Evaluation of the Fire Performance of H-Section Made of Ordinary Strength Structural Steels by Differences of Length
Authors: Kwon In Kyu
Published: February 2014

Fire resistance performance in steel building is very important for sustaining structural stability during a fire. However, the fire performance has been evaluated by fire test with only one length of the H-section made of an ordinary strength structural steel, such as SS 400 or SM 400. These have the same yield strength, but SM 400 has a better weldability. Therefore, the determination of fire protective materials can be difficult when the H-section made of SS 400 and SM 400 is applied into columns having different lengths are changed. In this paper, an evaluation was conducted to suggest a new guideline for the fire resistance of H-section built with an ordinary strength steels such as SS 400 and SM 400 and having variance of lengths. The results revealed the H-section made of SM 400 showed a little better fire resistance performance. Also, the longer the length of column, the less the fire resistance. Therefore, a new guideline is required to compensate the fire resistance of longer column than that from fire tested.
Corrosion Resistance of High-Alloyed Material UNS N08028 in Sodium Chloride Solution
Authors: Zhang Li Na , Szpunar Jerzy A. , Dong Jian Xin , Zhang Mai Cang
Published: February 2014

The influence of ions chloride concentration and pH value on the corrosion resistance of high-alloyed material UNS N08028 in the sodium chloride solution is investigated. Results show that the corrosion potential is active cathodically with the increase of chloride concentration. The current density and corrosion rate both increase with increasing chloride concentration and decreasing pH value.
Influences of Different Surface Treatments on Titanium Substrate to HA/TiO2 Bioactive Coatings
Authors: Wu Sheng Jiang , Shao Hui Ping , Wei Ran
Published: February 2014

The porous titanium alloy containing 17.5 wt% molybdenum elements prepared by gel-casting methods was used as precursor. The composite coatings with hydroxyapatite and TiO2 prepared on the precursor was treated respectively by NaOH solution, 30% H2O2+NH3 solution, HF+HNO3 and PdCl2 solution to improve the characterization of coatings. The microstructure was examined by SEM, and part of the coatings was examined by EDS to indicate the linear distribution of HA and TiO2. The corrosion behavior of the coatings in the simulated body fluids (SBF) was evaluated by potentiodynamic polarization test and impedance plots. The results showed that the corrosion resistance of the coatings treated with PdCl2 solution was better than the others. The passivation layer which played a key role in corrosion resistance was generated by PdCl2 solution treatment; their surface morphologies was more uniform than the others and had no crack; the thickness of the coatings was 60~70μm.
Comparison of DLC and N-Doped DLC Synthesized by RF-PECVD
Authors: Janchocktawee Witit , Rachpech Vishnu , Wannasin Jessada
Published: February 2014

Diamond-like carbon (DLC) films and nitrogen doped DLC (NDLC) were deposited on glass slide and H13 steel by plasma-enhanced chemical vapor deposition using a commercial RF 13.56 MHz (RF-PECVD). The films have been prepared from CH4 for DLC and CH4+N2 mixtures for NDLC. The deposition process was at 300°C under argon atmosphere for 120 min. Bonding energy and diamond like carbon characteristic of DLC and NDLC films have been characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy. Thermalgravimetric Analyzer (TGA) was used to evaluate the thermal stability of the films which were scrapped off from a glass slide substrate. The mechanical properties was characterized, such as hardness by nanoindentation technique, scratch test by Rockwell diamond tip in progressive mode and friction coefficient have been measured in ambient air using a ball-on-disk tribometer.
Numerical Simulation of Influence of Aggregate-Mortar Interface on Fracture Toughness of Concrete
Authors: Zhu Xiao Bin
Published: February 2014

To explore the feasibility of the approach of "interfacial toughening in concrete", the 2D concrete model which possesses the characteristic of random distribution of spherical aggregates was used to simulate the relations between interface material and toughness of concrete containing flexible interfacial material. The influence of interfacial material on the toughness of concrete was calculated with elastic modulus, thickness and the displacement at peak load for variables. And the results show that: The peak width of the concrete's load-displacement curve is increased evidently with the ultimate displacement also improved evidently upon replacing the normal ITZ with flexible interface phase material; the concrete's peak load, the displacement at peak load and the fracture energy increase gradually with the increase of the elastic modulus of interface phase material. When the elastic modulus exceeds 50MPa, the concrete's peak load will exceed that of normal concrete promptly with the displacement at peak load and the fracture energy all reaching the maximal value; With the gradual increase of the thickness of interface phase material, the concrete's peak load declines gradually while the displacement at peak load increases gradually; The concrete's fracture energy and ductility coefficient approximately increase first and then decline with the change of thickness. When the thickness is 0.2mm, the concrete's fracture energy and ductility coefficient reach the optimal value in setting scope. With the gradual increase of the interface phase material's displacement at peak load, the concretes peak load increases gradually while its fracture energy and ductility coefficient increase first and then decline. When the displacement at peak load is 0.05, the two reach the optimal value; when the displacement at peak load exceeds 0.05, the cracks will extend from the aggregates-mortar base debonding to the mortar matrix. The results have certain exploration value for developing concrete toughening technology.
Compressive and Tensile Strength of Two-Stage Concrete
Authors: Saud Abdullah F. , Abdelgader Hakim S. , El-Baden Ali S.
Published: February 2014

An experimental investigation was conducted to evaluate the compressive, tensile strength and modulus of elasticity of two-stage concrete (TSC) at different water-to-cement ratios. The primary objectives were to measure the elastic modulus, compressive strength and splitting tensile strength of TSC and to determine if there is a quantifiable relationship between compressive and tensile strength. Behavior of TSC in compression has been well documented, but there are little published data on its behavior in tension and modulus of elasticity. This paper presents the experimental results of preplaced, crushed granite aggregate concreted with five different mortar mixture proportions. A total of 48 concrete cylinders were tested in unconfined compression modulus of elasticity and splitting tension at 28 and 90 days. It was found that the modulus of elasticity and splitting tensile strength of two-stage concrete is equivalent or higher than that of conventional concrete at the same compressive strength. Splitting tensile strength can be conservatively estimated using the ACI equation for conventional concrete.
Fiber Reinforced Concrete Frame Shaking Table Test
Authors: Meng Guo Wang , Zhou Jia Mei , Sui Chuan Yi , Yan Qi
Published: February 2014

Two full scale frames were tested on a shaking table to investigate seismic performance and fracture mechanism of fiber reinforced concrete in contrast to the plain concrete. The information about acceleration response, the maximum strain value as well as the time to reach it, the typical strain - time curves and the crack development of two test frames were presented. Test results indicate that reinforced concrete did not crack during the test; the fiber reinforced concrete could better absorb or consume energy in the process of stress redistribution after peak acceleration; maximum strain and maximum acceleration did not occur at the same time; structure came into being deformation even failure when the seismic energy in the structure gone up to certain extent, and the dynamic failure would be their main failure modes.
Hysteretic Behavior of Damaged Walls Strengthened by Aramid Fiber Sheet and Additional Reinforcement
Authors: Lee Hyun Ho , Chun Young Soo
Published: February 2014

To improve the seismic performance of existing residential buildings, strengthening methods for T-shaped walls are evaluated through the performance tests. Almost damaged three specimens are strengthened by aramid fiber sheet and additional reinforcement. Cyclic lateral loads are applied to the top of the specimen with constant axial load. From these, strengthened wall by aramid fiber sheet and additional reinforcement shows the almost 100% strength and deformation capacity recovery comparing the undamaged wall. For the convenience of wall strengthening method in a residential state, using of aramid fiber sheet is recommended from this performance test results.
Influence of the Intermediate Annealing on Deformation Ability of the Cold Rolled Ring
Authors: Wei Wen Ting , Qin Xun Peng , Deng Song
Published: February 2014

This paper studies the influence of the intermediate annealing on deformation ability of the cold rolled ring. The results show that: intermediate annealing can improve the ability of plastic deformation of the cold rolled ring, ring rupture occurred after 62.5% thickness reduction, on the other side the ring suffering intermediate annealing still be intact by rolling to upon 64.8% thickness reduction. The mechanism of the intermediate annealing improving deformation ability of cold rolled ring is explored by using optical microscopy, scanning electron microscopy, micro hardness tester and other materials characterization methods. It is found that after intermediate annealing, the amount of carbide particles significantly reduce and the hardness decrease. Meanwhile, dissolution of partial carbides occur during the cold ring rolling process, and with the increasing of the cold rolling deformation, the quantity of the dissolution of cementite in pearlite will increase, which resulting in the improvement of the deformability of the cold rolled ring.
Calculation Method for Interference Value in Metal Joining Structure
Authors: Liu Ping , Zhang Kai Fu , Li Wan Li
Published: February 2014

Interference-fit joining is one of the important jointing methods to permanently fasten two thin-walled sheet metal parts. In joining process the interference amount is an important factor, which affects ultimate strength and fatigue life of the mechanical structure. In this article, analytical solution for interference value is studied, and the elastic and plastic deformation area near the hole is discussed. The calculation formula for the hole walls displacement and the boundary between elastic and plastic deformation is obtained.
Numerical Study on Normal Stress Distributions in a Single-Lap Adhesive Joint
Authors: He Xiao Cong , Wang Yu Qi
Published: February 2014

Adhesively bonding is becoming a widespread candidate technique for joining light-weight structural components. This paper investigates normal stress distribution in a single-lap adhesive joint using finite element method. Five layers of solid elements were used across the adhesive for obtaining an accurate indication of the variation of normal stress. All the numerical results obtained from the finite element analysis show that the spatial distribution of normal stress are similar for different interfaces. It can also be seen from the results that the left hand region is subjected to very high stress.
The Mode and Nature Frequency of Pipes Conveying Fluid with Distributed Follower Force on Two-Parameter Foundation
Authors: Huang Jian Hong , Guo Chang Qing
Published: February 2014

The vibration differential equation of pipes conveying fluid with distributed follower force on two-parameter foundation is derived, the mode and nature frequency of clamped-clamped pipes with distributed follower force are calculated by complex modal. The relations between the nature frequency and the velocity of foundation liner stiffness and shear stiffness and mass ratio are studied. The numerical calculation shows that these parameters have a great influence to the nature frequency of the system and have certain effects to the characters vibrations of pipes.
Study on EMI Reduction of DC-DC Buck Converter
Authors: Huang Long , Yu Fang Ping , Liu Tai Long , Li Peng , Wu Qi Dou , Jin Hua Biao
Published: February 2014

DC-DC buck converter has been more widely used in automotive electronics because of its advantage of high efficiency and small size. However, it is one of the main causes of the conducted emission and radiation noise. The working principle and the mechanism of DC-DC buck converter which generate conducted emission and radiation noise in different frequency were analyzed. Then, two methods were proposed to reduce the low frequency radiated emission. One is weakening the AC current value of the inductor current through increasing the value of the output inductor, the other is reducing the loop area by adding the output filter, and both of the methods were verified by comparative test. Finally, the two schemes were used in designing the On-board controller, and it passed the radiated emissions (ALSE method) according to the international standard CISPR 25-2008.
Synthesis and Characterization of a Novel Diphenylamine-Thiophene Compound for Blue Organic Light-Emitting Diodes
Authors: Li Jing Tong , Liu Ran Sheng , Zhao Zeng Dian , Yu Ru Jun
Published: February 2014

Diphenylamine and thiophene compounds are promising materials for organic light-emitting diodes (OLEDs). We report here, the synthesis and optical property of a novel small molecular weight derivative, N4.N4,N4'.N4'-tetrakis (4- (thiophen-2-yl) phenyl)-[1,1'-bipheny-4,4'-diamine (TPPA). The target molecule was synthesized using 4,4'-dibromobiphenyl as the starting material, and the proceeding reactions included bromination, Buchwald and Suzuki coupling reactions. According to the optical characterization of it, the absorption peak and excitation peak is at 351nm and 412 nm, respectively. The luminescence quantum yields (LQY) of TPPA is measured at 61.3%.
Density Functional Theory Study: Interactions of Lithium-Montmorillonite with Poly(Ethylene Oxide) as Preliminary Investigation of Lithium Polymer Conductivity
Authors: Lintangpradipto Muhammad Naufal , Wungu Triati Dewi Kencana , Lubis Ahmad H. , Dipojono Hermawan Kresno , Nugraha Nugraha
Published: February 2014

In this study, the interactions between poly (ethylene oxide) (PEO) and lithium-montmorillonite (LiMMT) have been investigated using density functional theory (DFT) calculation. The results of calculations show that the adsorption process of PEO on the LiMMT surface is physisorption with adsorption energy of -0.063 eV. This observation is consistent with the results of our calculations on PES (Potential Energy Surface) and PEC (Potential Energy Curve). The formation of space between PEO and LiMMT are found in range of 3.4 - 4.2 Å which are in good agreement with experimental results.
High Power LED Heat Dissipation Comparison Analysis via Aluminum and Copper Slug
Authors: Vairavan Rajendaran , Sauli Zaliman , Retnasamy Vithyacharan
Published: February 2014

The vast development of the LED industry has created contemporary set of thermal issues with limits the reliability of the high power LEDs. Thus, this paper reports a simulation analysis done on single chip high power LED package to evalute the effects of heat slug material on the heat dissipation of the LED package. The heat dissipation of two types of heat slug material, aluminum (Al) and copper (Cu) were compared in terms of junction temperature, von Mises stress and thermal resistance of the LED chip at varied input power of 0.1 W and 1W. Results of the analysis showed that the copper heat slug exhibits a better heat dissipation due to its superior thermal conductivity.
Study on the Properties of W-Al2O3 Solar Energy Selective Absorbing Coating Prepared by Magnetron Sputtering
Authors: Han Qiu Ling , Ye Wen Yu , Chen Qiao Ling , Gong Jian Hong
Published: February 2014

In this paper, the W-Al2O3 solar energy selective absorbing coating was prepared by magnetron sputtering. The selective absorption coating layers were obtained by setting different tungsten target sputtering power and sputtering time. The process parameters of magnetron sputtering were presented by comparing the selective absorption coating layers absorptivity and reflectivity.
Algae Biofilm on Indium Tin Oxide Electrode for Use in Biophotovoltaic Platforms
Authors: Ng Fong Lee , Phang Siew Moi , Periasamy Vengadesh , Yunus Kamran , Fisher Adrian C.
Published: February 2014

Algae are amongst the most photosynthetically efficient organisms harnessing solar energy for all its metabolic life-supporting activities. The solar energy is transformed into chemical energy in a normally wasteful process. In this study, this excess wasted energy may be directed towards electricity generation in a biophotovoltaic platform. This is a new approach in renewable energy production from algae. As an initial step, algal biofilms are established on indium tin oxide (ITO) anodes. Two microalgae, the unicellular Chlorella UMACC 313 and the filamentous Spirulina UMACC 159 were used to form biofilm on ITO anodes under three different treatments (T1: unmodified smooth surface , T2: modified surface etched with interval of 2.5 mm between lines and T3: modified surface etched with interval of 1 mm between lines). Results show significantly higher biofilm coverage on the etched anodes compared to the smooth ones. Anodes of T3 registered the highest biofilm coverage of 99.46% for Chlorella. For Spirulina, highest biofilm coverage (80.70%) was observed on T2 anodes. The increase in biofilm coverage successfully resulted in increase of photosynthetic efficiency for both strains. Spirulina registered the highest maximum relative electron transport rate at 153.507 μmol electrons m-2s-1 compared to Chlorella (140.796 μmol electrons m-2s-1). This was correlated to pigment content. Biofilms established on the ITO anodes and the resulting high rate of photosynthetic efficiency achieved in these experiments are expected to enable electrical energy production from biophotovoltaic platforms.
Effect of Exposure Time on Plasma Modified Polyvinylidenefluoride-Trifluoroethylene (PVDF-TrFE) Film Surfaces
Authors: Sarip Muhamad Naiman , Mohd Dahan Rozana , Yap Seong Ling , Wahid Mohamad Hafiz Mohd , Arshad Adillah Nurashikin , Kamarun Dzaraini
Published: February 2014

This study investigates the plasma surface modified spin coated PVDF-TrFE (70/30) film of 200nm thick using Atomic Force Microscopy (AFM), Water Contact Angle (WCA) and Fourier Transform Infrared Spectroscopy (FTIR). The surface of the spin coated PVDF-TrFE film were modified using 13.56 MHz rf Argon plasma. The exposure time of the charged particle on PVDF-TrFE films were varied for 1, 3, 5, 7 and 9mins. Prior to modification, the average surface roughness observed was 3.5nm. However upon modification, the surface roughness was increased to 9.5nm. The contact angle of the surface modified film was reduced from 89° to 58°. The increase in surface roughness and wettability of the modified film provided good biocompatibility. This finding created great interest in developing functional polymer suitable for applications in areas such are biomedical, bio-analytical assays, textile and even food industry.
Characterization on Optical and Mechanical Properties of Low-Density Polyethylene Films Doped with Eu(III) Complex
Authors: Nordin Mohd Nasha’ain , Mohd Azmi Nik , Hashim Hasrina , Abdullah Ahmad Makarimi , Shualdi Wedianti , Ezwan Mohamed Izat , Mohd Isha Khairuldin , Ismail Farehah
Published: February 2014

Low-Density Polyethylene films of 100 μm thickness doped with Eu (TTA)3phen complex was hot-blown by a lab scale extrusion process. The ratio of the complex was varied from 0%, 0.025%, 0.5%, 0.1%, to 0.2% with respect to the total weight of LDPE. The mechanical properties of the films were measured according to ASTM D882, and ASTM D1938 standards. The optical and chemical properties were characterized by spectrofluorometer and FTIR respectively. FTIR characterization shows that Eu (TTA)3phen in LDPE films does not exhibit spectrum due to the dominant nature of amorphous LDPE. All emission transition lines of Eu3+ ion for doped films were observed when excited at 394 nm, and the highest peak was detected at 608 nm. The peak intensity reached a saturation level at 0.1% doping ratio, while mechanical test showed that the tensile strength (TS) and elongation at break (EB) of machine direction (MD) oriented films decreased with increasing ratio of the complex, in which at doping ratio of 0.2%, both values dropped by 17.8% and 11.6% respectively.. These results indicate that different doped ratio of Eu (TTA)3phen affect significantly the film properties which offer possibility for an improved photoselective greenhouse plastic films. Keywords; LDPE, Eu (TTA)3phen, Photoluminescence.
Effect of Thickness and Annealing Temperature on the Properties of PZT Films at Morphotropic Phase Boundary Composition Prepared by Sol-Gel Spin-On Technique
Authors: Periyannan Jegatheesan , Muniyandi Muneewaran , Venkatesan Giridharan Nambi
Published: February 2014

Pb (ZrxTi1-x)O3 films at morphotropic phase boundary composition (x=0.52) were deposited on Pt/Ti/SiO2/Si substrates by sol-gel spin on technique. Thickness of the films were varied up to 1μm by step-by-step crystallization process and annealed at 500, 600 and 700 °C. Films annealed at 500 °C had poor degree of crystallization for all the thicknesses while 600 and 700 °C annealed films were found to be well crystallized with a (111) preferential orientation. Also an enhanced degree of preferential orientation was observed on the films annealed at 600 °C compared to films annealed at 700 °C. Room temperature dielectric measurements showed higher dielectric constant values for the films annealed at 600 °C compared to films annealed at 700 °C. The remnant polarization (Pr) and coercive field (Ec) at an applied field of 160 kV/cm depicted that 600 °C annealed films had a higher Pr and lower Ec values compared with the 700 °C annealed films attributed to the higher degree of preferential orientation.
Substrate-Free Thick-Film Lead Zirconate Titanate (PZT) Performance Measurement Using Berlincourt Method
Authors: Kok Swee Leong , Lau Kok Tee , Ahsan Qumrul
Published: February 2014

Lead Zirconate Titanate or PZT is a high performance piezoelectric material which is able to generate charges when a proportional amount of stress is applied on the material. It has the potential to be used to fabricate micro-power generator for powering low power electronic devices, on top of already existence sensors and actuators. One of the indicators for comparing the performance of the smart materials is the piezoelectric charge coefficient, d33. In this paper, the actual d33 of PZT fabricated in the form of substrate-free thick-films were measured using Berlincourt Method whereby a standard dynamic force is applied to the materials and the resultant value of charges is recorded and compared over a period of time after the thick-films were polarized. The d33 values are compared between substrate-based and substrate-free specimens show a difference of about 45 % as a result of clamping effect contributed by d31. The experiment results also show that the thick-film PZT processed at 950 °C and polarized at 220 V with a thickness of about 120 μm has a piezoelectric charge coefficient of 82 pC/N.
Optical Properties of Zinc Oxide (ZnO) Thin Films Prepared by Spray Pyrolysis Method
Authors: Rajendra B.V. , Bhat Vinayak , Kekuda Dhananjaya
Published: February 2014

Zinc oxide (ZnO) thin films were deposited on the glass substrates using Zinc acetate dehydrate solution through spray pyrolysis method. The films were obtained by spraying 0.05M concentrated solution at a rate of 0.5ml for 10 min and were deposited at different substrate temperatures ranging from 473K to 673K. A comprehensive study was carried out to realize the effect of substrate temperatures and subsequent annealing on optical properties of the ZnO thin films. It was observed that the band gap energy decreases with increases the substrate temperature and annealing. Optical constants such as the refractive index n and extinction coefficient k were determined from transmittance spectrum in the ultravioletvisible (UVVIS) regions by Swanepoel envelope method and crystallinity was confirmed by Urbach tail and atomic force microscope images.