bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity Analysis of Material Constitutive Model Parameters in Numerical Simulation of the Orthogonal Turning Process
Authors: Sekar K.S. Vijay , Pradeep Kumar M.
Published: August 2015

Numerical simulations in machining processes are dependent on the flow stress input data. The flow stress is computed from empirical models which depend on number of material parameters, the values of which are derived from various mathematical optimization techniques. The derived flow stress parameters vary based on the nature of techniques used and the flow stress testing procedure utilized. This results in variations in the numerical simulation results when working with different models. In this work, the Johnson Cook flow stress model is tested for its sensitivity towards the finite element (FE) results. Orthogonal turning is conducted with AA 6082 (T6) aluminium alloy and the process is simulated in Deform 2D. The flow stress computed from the Johnson Cook model is input to the FE code and the cutting force and chip thickness recorded. The FE results are input to the Minitab statistical code and an optimization process conducted based on the orthogonal arrays concept. The comparative study reveals the sensitivity of the five parameters of the material model towards the cutting force and chip thickness.
Determination of Optimum Parameter Levels for Quality Characteristics in Conventional Drilling of Thick Polymeric Composites
Authors: Balasubramanian Ramesh , Elayaperumal A. , Satishkumar S.
Published: August 2015

Since literature on the machinability of non laminated composites is scarce, an investigation was extended away to study the machinability of thick non laminated Glass Fiber Reinforced Plastic (GFRP) composites and to compare the above with machinability of thick laminated composites. The composites with high fiber weight fraction were drilled with a special geometry coated carbide drill (Ratio drill). Taguchi’s orthogonal array and analysis of variance (ANOVA) were used to examine the influence of process parameters (feed and spindle speed) on quality characteristics (thrust force and torque). The optimum degree of process parameters towards aperture quality was obtained.
Laser Surface Melting of Ti6Al4V Alloy with Ti-BN-C Mixed Powders
Authors: Zeng Xian , Yamaguchi Tomiko , Nishio Kazumasa
Published: August 2015

Laser surface melting was carried out on the surface of Ti-6Al-4V alloy with Ti-BN-C mixed powders. In this paper, an influence of the mole ratio of BN/ C on microstructure, chemical composition, element distribution and hardness were separately analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe micro-analyzer (EPMA) and Vickers hardness test (HV). The results showed that the melting layer mainly consisted of TiCxN1-x (x=0, 0.3, 0.7), TiB and Ti. The hardness was increased with improving the mole ratio of BN/C ratio.
Processing of High Strength Magnesium Alloy with Enhanced Plasticity Using Squeeze Casting
Authors: Tun Khin Sandar , Sim Goh Chwee , Tan Xing He , Chan Kwok Weng Jimmy , Kwok Wai Onn Richard , Lee Teck Kheng , Gupta Manoj
Published: August 2015

Crystalline Mg-Cu-Y alloy system was fabricated using the squeeze casting technique. Microstructure showed the multiphase structure composed of primary Mg rich phase distributed among the lamellae patterns, alternative layers of LPSO Mg phase and intermetallic phases. High microhardness and tensile strength of 104 HV and 223 MPa respectively were observed in the squeeze cast alloy. A good combination of compressive strength (706 MPa) and ductility (19%) was also achieved in the crystalline alloy which is unlikely to be attainable in amorphous Mg-Cu-Y system. The formation of LPSO phase in the current Mg-Cu-Y alloy mainly contributed to the high mechanical properties.
Effect of Incremental Forming Process Parameters on Aluminum Alloy Using Experimental Studies
Authors: Majagi Sunil D. , Chandramohan G. , Senthil Kumar Mouleeswaran
Published: August 2015

Incremental Sheet Forming (ISF) process is Innovative and cost effective technology trend for forming products in manufacturing industries. The current research is to study and investigate the influence of incremental sheet forming process parameters on response surfaces of aluminium alloy sheet components. In this experiment, Aluminium alloy AA1050 sheet was selected to process forming by using CNC machining centre without expensive dies. Individual and interactive effect of different factors such as, thickness of sheet, tool diameter, vertical step, feed rate, and tool rotational speed at different levels were assessed to improve the processing time. For the design of experiment (DOE), Taguchi’s L27 orthogonal array was used to investigate and optimize the influencing ISF process parameters. From ANOVA results, it was found that for thickness reduction, the influencing factors were as following; feed rate (21.40 %); for roughness, tool rotation speed (20.43 %) and for hardness, thicknesses of sheet (39.49 %). Response Surface Methodology (RSM) showed that optimal values obtained were 0.46 mm, 10 mm, 0.6818 mm, 2232.32 mm/min., and 2626 rpm for thickness of sheet, tool diameter, vertical step, feed rate and tool rotational speed respectively. For percentage thickness reduction of 59.6%, minimum roughness 2.09μm, and maximum hardness 41.7 BHN, the confirmatory test showed values of 64.78 % thickness reduction, roughness of 2.14μm and hardness of 44.82 BHN that were in agreement with the predicted value.
Surface Morphology and Wear Analysis of Stellite 6 Deposited on 9Cr-1Mo Steel Substrate by Laser Cladding
Authors: Kusmoko Alain , Li Hui Jun
Published: August 2015

Stellite 6 was deposited by laser cladding on a 9Cr-1Mo (P91) substrate with energy inputs of 1 kW (P91-1) and 1.8 kW (P91-1.8). The chemical compositions, microstructures and surface roughnesses of these coatings were characterized by atomic absorption spectroscopy, optical microscopy, scanning electron microscopy and atomic force microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was evaluated using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the 9Cr-1Mo (P91) steel substrate with the lower heat input (P91-1). Further, the Stellite coating for P91-1 was significantly harder than that obtained for P91-1.8. The wear test results indicated that the weight loss for P91-1 was much lower than for P91-1.8. The surface topography data indicated that the surface roughness for P91-1 was much lower than for P91-1.8. It is concluded that the lower hardness of the coating for P91-1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating.
Effect of Surface Stress on the Deformation of an Half-Plane Applied to Nanometer Materials
Authors: Ou Zhi Ying , Guo Jing
Published: August 2015

Based on the two distinct solutions, as classical solution for an elastic half space containing a circular hole at nanoscale, the complex variable and superposition method was proposed and employed to investigate the state of stress and displacement in an half space with surface tension for nanoelastic material.The results indicate some characteristics in half space which are different from those in classical elasticity theory .
Influence of Inner Steel Tube Diameter on Compressive Behavior of Square FRP-HSC-Steel Double-Skin Tubular Columns
Authors: Louk Fanggi Butje Alfonsius , Ozbakkloglu Togay
Published: August 2015

FRP-concrete-steel double-skin tubular columns (DSTCs) are a new form composite column system that effectively combines the advantages of the constituent materials. The performance of this column system has been experimentally investigated in a number of recent studies. However, apart from a single study reported on square DSTCs, all of the existing studies have been concerned with DSTCs with circular external tubes. This paper reports on part of an ongoing experimental program at the University of Adelaide on FRP-concrete-steel composite columns. The results from 12 square hollow and concrete-filled DSTCs and six companion hollow concrete-filled FRP tubes (H-CFFTs) that were tested under axial compression are presented. Results of the experimental study indicate that hollow DSTCs with larger inner steel tube diameters develop similar ultimate axial stresses to but significantly larger axial strains than companion DSTCs with smaller inner steel tubes. The results also show that, in concrete-filled DSTCs with similar Ds/ts ratios, an increase in the steel tube diameter leads to an increase in both axial stress and strain of concrete. It was observed that H-CFFTs perform significantly worse than both hollow and filled DSTCs under axial compression, and their behavior further degrades with an increase in the diameter of their inner voids.
Nano-Scale Friction of Multi-Phase Powder Metallurgy Tool Steels
Authors: Gåård Anders , Karlsson Patrik , Krakhmalev Pavel , Broitman Esteban
Published: August 2015

Friction is a fundamental phenomenon in tribology involving complex mechanisms between the contacting surfaces. Measurements of friction are often made using devices with substantially larger contact area than dimensions corresponding to microstructural features of the materials. Hence, for multi-phase materials, influence of particular microstructural constituents is not resolved. In the present work, a tribometer with a contact area in the nanoscale range was used to map friction for different types of tool steels with different chemical-and phase composition. Owing to the small tip radius, frictional characteristics of primary carbides and the steel matrix were measured and compared. Depending on chemical composition, a difference was observed where the coefficient of friction was approximately twice higher for the steel possessing highest coefficient of friction, including both carbides and the steel matrix.
First Evaluation of the Structural Performance of Traditional Brickwork after Standard Fire Exposure
Authors: Sciarretta Francesca
Published: August 2015

The paper addresses the issues of fire behavior of masonry walls made of traditional/historical component materials (bricks and mortar). There are reasons for coupling investigations on the residual mechanical properties to fire resistance data, aiming at a more complete knowledge of the behavior of a masonry member during and after fire exposure. The paper is part of a research that aims at investigating the relationship between fire and post-fire (i.e. residual) mechanical behavior of masonry walls, paying attention to scale-related problems and to the possible exploitation of numerical tools to establish simplified approaches. The goal is to establish relationships between fire resistance ratings under exposure and decay in mechanical properties after exposure; the parameter of wall thickness is especially investigated, by choosing four different values (i.e. 12, 25, 38 and 51 cm). This is performed by means of FEM analysis with DIANA 9.4.4 software, simulating a standard ISO 834 fire resistance test followed by a mechanical compressive failure test on each investigated type of wall. The approach, successfully tested against experimental data already available, features a preliminary transient heat flow analysis which gives a numerical prediction of fire resistance after violation of I (Insulation) criterion; then, a staggered heat flow - stress analysis repeats the heating of the wall up to insulation failure and calculates the thermal strain accounting for cracking; finally, a ‘cold’ structural analysis in compression is performed on the thermally-deformed model after cooling. The paper also addresses a way for the extended application of the research outcomes, relying on a simple approach based on the concept of equivalent fire severity.
Influences of Concentric and Eccentric Loads on Buckling of Fixed-End Supported Pultruded FRP Channel Beams
Authors: Thumrongvut Jaksada , Seangatith Sittichai
Published: August 2015

This paper presents the results of the experimental research performed on the pultruded FRP (PFRP) channel beams subjected to transversely concentric and eccentric loads. The objectives of the research work are to investigate their structural behaviors and to determine the critical buckling moments and modes of failure of the beams with various span-to-depth ratios and eccentricities. Pultruded beams are fixed-end supported at both ends for major and minor-axis flexure. The beam specimens have the cross-sectional dimension of 102×29×6 mm with span-to-depth ratios, ranging from 20 to 40. A total of 40 mono-symmetric section tests were performed. The effects of vertical load position through the cross-section were studied. Also, shear center position with concentric load and three different eccentricities were investigated ranging from 0 to-3e. The specimens were tested to final buckling. Based upon the results of this study, it is found that the load versus mid-span vertical deflection relationships of the beams are linear up to the failure. On the contrary, the load versus mid-span lateral deflection relationships are geometrically nonlinear. The general mode of failure is the flexural-torsional buckling. The eccentrically loaded specimens are failed at buckling loads lower than their concentric counterparts. Overall, the critical buckling moment decreases as the magnitude of eccentricity increases. Additionally, it is noticed that L/d ratio increases, the critical buckling moment is decreased.
Response of Circular Footing on New Key Engineering Material - Granulated Blast Furnace Slag as Structural Fill
Authors: Yadu Laxmikant , Tripathi R.K.
Published: August 2015

Granulated Blast furnace Slag (GBS) has good potential to be use as granular material in place of conventional granular materials i.e. sand and aggregate. It can be use as structural fill in low laying areas. In such cases, it is required to evaluate the bearing capacity of the fill and reinforced it with some suitable reinforcing materials to enhance the bearing capacity. In this study, Response of circular footing was studied by using GBS as fill material and geogrid as reinforcing material. Only one geometric parameter i.e. number of geogrid layers was considered to get the response of circular footing. Two numbers of geogrid layers were obtained as optimum parameters and it increases the ultimate bearing capacity 94% and decreases the settlement by 45% as compared to unreinforced GBS bed.
Effect of Minimum Quantity Lubricant of Al203 Nanoparticle with SDBS on Surface Roughness during Turning of Mild Steel
Authors: Ali M.A.M. , Khalil A.N.M. , Azmi Azwan Iskandar
Published: August 2015

This work presents a study on the effect of Minimum Quantity Lubricant of Al203 nanoparticle with Sodium Dodecylbenzene Sulfonate, SDBS on surface roughness during turning of Mild Steel under constant machining parameters. Surfactant, SDBS in the nanolubricant creates stability of the particles in the base fluid. The experiments were conducted under dry, MQL with pure nanolubricant, and MQL with nanolubricant and additional SDBS. The experimental results showed that MQL nanolubricant with additional SDBS improves the surface roughness compared to dry cutting.
The Investigation of the Factors of the Fracture Toughness Based on the Compact Tension Specimen
Authors: Wang Yan Wei , Du Xuan , Zou Guang Ping , Ma Cong Bo
Published: August 2015

This article studies the fracture behavior of compact tension specimens under tensile loading. The test - numerical hybrid method is used to explore the effect of the location of the loading hole. And the size effect is also considered to analysis the reason of fracture behavior .The initial load for numerical simulation is based on the experimental data. In that case, the numerical simulation results can be used to study the effect of the location of the loading hole and also the size effect to the specimens.
Research on Damage Mechanism of Aluminum Foam Sandwich Plate Subjected to Blast Loading
Authors: Wang Zheng , Yu Wen Li , Wang Tao , Wang Jin Tao
Published: August 2015

This paper investigated the damage degree and damage mechanism of aluminum sandwich plate subjected to blast loading by using numerical simulation method. Finite elements models of aluminum foam sandwich plates were established. The distortion and damage pattern of the sandwich plate under different masses of detonator were got by using LS-DYNA to simulate the destructive effect of shock wave and detonation product against sandwich plate. The results showed that the maximal deflection and overloading of the sandwich plates were different because of the changing of mass of detonator. This paper could provide some reference for the designing of sandwich structures.
Impact of Nanoparticles on Structure and Functional Properties of PBTG Biofilms
Authors: Park Young Shin , Joo Chang Whan
Published: August 2015

Biopolymer composites are required to enhance their mechanical properties and heat resistance for the industrial applications. Especially, the addition of nanoparticles in biopolymers can give various functionalities such as electrical, thermal and mechanical properties. In this study, the nanoparticles having functional characteristics were used to enhance heat resistance, tensile properties, and electrical conductivity of PBTG biofilms. Changes in tensile, crystalline and thermal properties of PBTG films with different additives (carbon black, sepiolite, zinc oxide, MWCNT) were investigated by the tensile tester and the instrument of XRD, DSC and TGA. As the results, Electrical conductivity of the biofilms was improved up to 10-5S/cm by adding MWCNT. And tensile modulus of PBTG biofilms with MWCNT was 1.37 times higher than the pure PBTG film. But their heat-resistance characteristics were not significantly affected by adding nanoparticles.
Sintered SiO2 Modulus of Rupture Optimization by Means of Artificial Neural Networks
Authors: Kvíčala Miroslav , Štamborská Michaela
Published: August 2015

This article discusses the use of artificial neural networks for solving industrial non-trivial problem, which is undoubtedly modulus of rupture optimization in case of sintered ceramics based on amorphous SiO2. Melting crucibles made from high purity silica are commonly used for production of high purity silicon ingots that are used in photovoltaic industry. Optimal modulus of rupture is very important variable that is related to the reliability and crucible usage value.
Silver-Mediated Perylene–3, 4, 9, 10–Tetracarboxylate Tetrapotassium Salt Aggregation for Highly Sensitive Detection of Iodide in Water
Authors: Ma Jia Jun , Yin Lei Cheng , Zou Gang , Zhang Qi Jin
Published: August 2015

A simple fluorescent iodide ion sensor was fabricated. Ag+ was found to specifically induce the aggregation of perylene–3, 4, 9, 10–tetracarboxylate tetrapotassium salt (PTK) in water, simultaneously, fluorescence of PTK was quenched. The resultant PTK–Ag+ aggregates showed a "turn–on" fluorescence response for halide ion, especially I-, and excellent selectivity toward possible interfering anions, contain sulfide.
A Phenomenological Predictive Model for Thermo-Mechanical Fatigue of Notched Type 304 Stainless Steel
Authors: Karl Justin O. , Copeland Andrew T. , Besio Amy K.
Published: August 2015

The behavior of parts subjected to simultaneous thermal and mechanical fatigue loads is an area of research that carries great significance in the power generation, petrochemical, and aerospace industries. Machinery with expensive components undergo varying applications of force while exposed to variable temperature working fluids. An example case is found in steam turbines, which subject stainless steel blades to cyclic loads from rotation as well as the passing of heated gases. Accurate service life prediction is especially challenging due to the thermo-mechanical loading being present on the complex geometric profile of the blades. This research puts forth a method for determining crack initiation lifetimes in variably-notched type 304 austenitic stainless steel specimens subjected to differing fatigue and thermo-mechanical fatigue conditions. A base analytical model and genetic algorithm were used to develop phenomenology-informed predictions that fall within a factor of two of the actual crack initiation times.
Study of Sodium Chloride’s Effect on Warm Fog Dissipation and its Mechanism Research
Authors: Xing Xiao Hui , Song Ting Lu , Li Xiao Dong , Zhang Qiang , Yang Rong Jie
Published: August 2015

Sodium chloride (NaCl) is often used for warm mist elimination because of its easy deliquescence performance. In this paper, how dosages of NaCl with two sizes affect warm fog was investigated. The changes of light transmittance (T) and fog drops inside the fog chamber were monitored. Results indicate that NaCl particles smaller than 40μm work better than that of 40-100μm, shortening time of the light transmittance recovering to 60%(t60%) by 83.3% with 25g. Reasons for this are they can decrease the percentages of small droplets, increase that of large droplets and the average sizes of fog drops, which are results from the condensation growth and coalescence growth.
The Dynamic Mechanical Analysis of a Clamped-Free Timoshenko Nano-Beam Subjected to the Moving Force the Nonlocal Effects
Authors: Lei Dong Xia , Huo Zhan Lei , Ou Zhi Ying
Published: August 2015

Based on nonlocal beam theories, the dynamic mechanical behavior of a clamped-free Timoshenko nano-beam subjected to a variable speed moving force are studied in this paper. The analytical solution of differential equation is obtained using state-space method. The effects of the nonlocal stress and the magnitude of the moving force acceleration on the dynamic responses of the nano-beam are discussed in detail. The results indicate that nonlocal effects and moving force acceleration play a significant role on the dynamic mechanical response of nano-beam.
Study of Nanocrystalline ZnAl2O4 and ZnFe2O4 with SiO2 on Structural and Optical Properties Synthesized by Sol-Gel Method
Authors: Zulfakar Mohd Syafiq , Abdullah Huda , Wan Jalal Wan Nasarudin , Zainuddin Zalita , Shaari Sahbudin
Published: August 2015

Zinc aluminate (ZnAl2O4) and zinc ferrite (ZnFe2O4) nanocrystalline structures dispersed into SiO2 matrix were prepared by sol-gel method. Phase formation of ZnAl2O4 and ZnFe2O4 was confirmed by X-ray diffraction (XRD) analysis. The crystallite sizes was determine using Scherer’s equation from the broadening of dominant peak at (311) plane. It was found the crystallite size of both compound decreased due to the decrement compositions of Zn2+ ion and Al3+ / Fe3+ ions. The crystallite sizes for ZnAl2O4 and ZnFe2O4 was calculated to be around ~ 14.16 – 11.27 nm and ~ 11.27 – 4.72 nm, respectively. FTIR analysis was done to determine the formation of spinel structures. FTIR results analysis confirmed that the formation of spinel structure where it has been observed that the bands around 800 cm-1 was associated to the vibrations of aluminum-oxygen and metal-oxygen-aluminum bonds. This characteristic was identified to the formation of zinc aluminate spinel structure. The optical properties have been done to determine the energy bandgap of ZnAl2O4 and ZnFe2O4 samples. The Uv-Visible absorption spectra have been done within wavelength 300 – 800 nm and the graph was plotted into the Tauc plot. This new dielectric material was purposed to improve the value of dielectric permittivity with addition of SiO2 where it can be applied as microwave dielectric material without changing the original spinel structures.
Effect of Cold Deformation on Precipitation of 7050 Aluminum Alloy during Aging Process
Authors: Yan Hong Wei , Zhen Liang , Jiang Jian Tang
Published: August 2015

Strengthening of aluminum alloy has always been an interesting research topic. There might be interactions between different strengthening mechanisms. In this paper, the effect of large cold deformation on the precipitation of as-quenched 7050 aluminum alloy was studied. Differential scanning calorimetry was used as the main research technique, accompanied by tensile test and transmission electron microscopy. It was found that clusters and precipitation had formed in the cold deformation, and dislocations accelerated the precipitation dynamics.
Failure Analysis of a 304 Stainless Steel Flange
Authors: Lu Jian Shu , Xuan Hui Fen , Xue Jin
Published: August 2015

An investigation for the cracking mechanism of a 304 stainless steel flange was carried out. The flange was installed in a (NH4)2SO4 tank . Optical microscopy examination shows that the cracking is intergrainular. SEM examination shows that the brittle nature of the cracked surface morphology. EDS analysis shows that chloride exists on the cracked surface. Electrolytic etching of the stainless steel in oxalic acid solution reveals that it has intergrainular corrosion sensitivity. The results show that poor welding operation caused to form defects in the weld. Corrosion occurred preferentially in the defect area and cracks propagated circumferentially in the weld seam. The crack propagation direction changed at a point where there was a large circumferential stress.
Study of Micro-Abrasive Wear Resistance of Heat Treated NiTi Alloys
Authors: Muterlle Palloma Vieira , de Barros Casto Ítalo , Herrera Paulo
Published: August 2015

The Nickel Titanium (NiTi) alloy is a shape memory alloy. It presents two distinct properties: shape memory effect (martensite phase at room temperature) and the pseudoelasticity (austenite phase at room temperature). These materials are frequently used in industries like engineering, dentistry, medicine and aeronautics, and for certain applications it is important to know the wear behavior of these alloys.Thus, this study aims to evaluate the micro-abrasive wear behavior of pseudoelastic NiTi alloys at the as received and aged conditions, and compare with results obtained for NiTi alloy with shape memory effect. The aging heat treatment was performed at temperatures of 350, 450, 500 and 600 °C with an isotherm of 30 minutes and subsequent quenching in water. The wear tests were carried out in a free ball machine. After wear testing was observed that the wear coefficient obtained were lower for all treatment temperatures when compared to pseudoelastic NiTi alloy as received, reducing wear by 30 % in case of treatment at 350 °C. The alloy with shape memory effect showed good wear behavior, with a wear coefficient about 14 % less than the untreated pseudoelastic NiTi alloy.
Research on Mechanical Properties of Micro-Electroforming Ni
Authors: Zhang Jing , Sui Li , Wang Zi , Shi Geng Chen
Published: August 2015

As one of the key techniques for manufacturing three-dimensional metal microstructure, micro-electroforming processing technology plays an important role in MEMS. Mechanical properties of micro-electroforming Ni have become a new research hotspot. This paper gives a brief overview of micro-electroforming Ni material’s mechanical properties. Due to the complexity and lack of standardization during micro-electroforming process, mechanical properties are found to be dependent on micro-electroforming process parameters and conditions. It is essential to reveal the essence of mechanical properties from microcosmic aspect. This paper briefly summarizes observation tools of microstructure and reviews the relationship of mechanical properties and microstructure. This work lays theoretical foundation for dynamic analysis and calculation of micro-electroforming Ni devices.
Study on the Microstructure and Storage Heat Performance of Mg-25Al-15Zn-xCu Alloys
Authors: Wen Hong Yan , Fan Xiao Ming , Cheng Xiao Min
Published: August 2015

With the help of optical microstructure(OM), X-ray diffraction(XRD) and differential scanning calorimetry(DSC), the microstructure and storage heat performance of Mg-based phase change thermal storage alloys were investigated.The results show that the microstructure of Mg-25Al-15Zn-xCu (x=0, 2%, 8% and 14%, respectivly) alloys are mainly composed of primary crystal α (Mg) solid solution matrix, β-Mg17Al12, CuZn, MgAl2Cu and Mg32(Al,Zn)49 phases. The phase transition temperature of Mg-25Al-15Zn and Mg-25Al-15Zn-8Cu alloys ​​are 412.1 °C and 405.9 °C respectively; and phase change latent heat values of that were 175.4 J/g and 209.3 J/g. The addition of Cu led to the formation of new phase, reducing the phase transition temperature and increasing the value of phase change latent heat.
Relationship of Microstructure and Mechanical Properties in Er-Containing Aluminum Alloy
Authors: Lei Xin , Huang Hui , Wen S.P.
Published: August 2015

This study investigated the mechanical properties and microstructures of Er-containing Al–Mg alloys. The research found that the H114-T sheet of Er-containing Al–Mg alloys showed a relative good comprehensive performance in mechanical properties. With the special rolling and heat treatment process, this H114-T sheet showed different morphology of microstructures with the other sheets in Er-containing Al–Mg alloys. Grains in H114-T sheet performed irregular shape polygon, a number of subgrains appeared in grains, the amount of dislocations in grains decreased. H114-T sheet possessed a lot of Copper texture, this may be one of important factors influenced the mechanical properties.
In Situ X-Ray Diffraction during Casting: Study of Hot Tearing in Al-Zn Alloys
Authors: Drezet Jean Marie , Mireux Bastien , Kurtuldu Guven
Published: August 2015

During solidification of metallic alloys, coalescence corresponds to the formation of solid bridges between grains when both solid and liquid phases are percolated. As such, it represents a key transition with respect to the mechanical behaviour of solidifying alloys and to the prediction of solidification cracking. Coalescence starts at the coherency point when the grains begin to touch each other, but are unable to sustain any tensile loads. It ends up at the rigidity temperature when the solid phase is sufficiently coalesced to transmit macroscopic tensile strains and stresses. This temperature, also called mechanical or tensile coherency temperature, is a major input parameter in numerical modelling of solidification processes as it defines the point at which thermally induced deformations start to generate internal stresses in a casting. The rigidity temperature has been determined in Al Zn alloys using in situ X-ray diffraction (XRD) during casting in a dog bone shaped mould. This set-up allows the sample to build up internal stress naturally as its contraction is prevented. The cooling on both extremities of the mould induces a hot spot at the middle of the sample which is irradiated by X-rays. Diffraction patterns were recorded every 0.5 s using a detector covering a 426 x 426 mm2area. The change of diffraction angles allowed us to observe agglomeration/decohesion of growing grain clusters and to determine a solid volume fraction at rigidity around 98 % depending on solidification time for grain refined Al 6.2 wt% Zn alloys.
Electrochemical Properties of Chemically Etched-NbO2 as a Negative Electrode Material for Lithium Ion Batteries
Authors: Cho Yong Hoon , Jeong Soon Ki , Kim Yang Soo
Published: August 2015

The electrochemical properties niobium dioxide (NbO2) was investigated as a negative electrode material for lithium ion batteries. The NbO2electrode showed a large irreversible capacity and small discharge capacity. The results of X-ray photoelectron spectroscopy indicate that the poor electrode performance of NbO2may be caused by niobium pentoxide (Nb2O5) formed on the surface of active material. The Nb2O5could be removed by chemical etching to some extent, thus improving the electrode performance.
Numerical Simulation Analysis for Padding Assisted Roll-Bending Process
Authors: Chen Bao Guo , Huang Zhi Bin , He Xue Ting , Liu Lei , Zhao Zhi Bo
Published: August 2015

Padding assisted roll-bending process is an advanced method to manufacture cylindrical thin-walled structure with variable thickness. A finite element model was established to study the deformation behavior of the padding assisted roll-bending process. In the numerical simulation model, aluminum sheet was selected as an elasto-plastic model, and nylon material was as an elastic model. The research results show that the radius of roll-bent thin-walled aluminum cylinder decreases with increasing of padding material’s stiffness, decreasing of the thickness ratio of nylon-to-metal and increasing of the roller stroke, and that an appropriate thickness compensation of padding material can improve the curvature consistency of cylindrical thin-walled structure with variable thickness.
A Preliminary Study on Li4Ti5O12 as a Novel Electrode Material for Calcium Ion Batteries
Authors: Kim Chang Su , Jeong Yun Taek , Jeong Soon Ki
Published: August 2015

The electrochemical behaviors of a spinel lithium titanate oxide (Li4Ti5O12, LTO) electrode during as a novel electrode for calcium ion batteries were investigated during the charging and discharging to understand its electrochemical properties. The electrochemical performance of the LTO electrode was improved by the addition of dimethyl carbonate to the PC-based electrolyte. The initial charge and discharge capacities were ~262 and ~85 mAh g–1, respectively. The results of the X-ray diffraction analysis showed that the lattice constant of LTO increased after charging, indicating that calcium ions were inserted into Li4Ti5O12during the charging.
Study on the High Shear Degassing Process with Water Simulation
Authors: Kang Yi Yao , Lin Yue , Liu Xu Dong , Sun Chao , Yuan Sen Sen , Zuo Yu Bo , Cui Jian Zhong
Published: August 2015

Hydrogen as the main cause of the gas porosity in aluminium alloys should be removed before casting. The degassing process with intensive melt shearing shows a high efficiency. In the present work, the water simulation was used to study the high shear degassing process and the effect of rotation speed on the size and distribution of inert gas bubbles. The results show that with the increase of rotation speed, the bubble size decreases and the affected region becomes larger. The proper rotation speed of the rotor for the rotor-stator high shear degassing process is 5000-6000 RPM.
Research on the Elimination of Banded Structure in SAE8620H Gear Steel
Authors: Li Jing , Lin Zhen Ming , Zhang Heng Hua , Jin Man
Published: August 2015

In order to eliminating the banded structure in SAE8620H gear steel,an isothermal annealing process and its mechanism has been studied in this paper. Results showed that isothermal annealing process can effectively eliminate banded structure in SAE8620H gear steel.With isothermal temperature 640°C-a certain low temperature indeed high undercooling,and for high nucleation at this temperature resulting in the decrease of nucleation rate difference in all areas,banded structure level decreased to 1 level.When isothermal temperature decreased to 610°C and 590°C,although the undercooling is so high that various regions began to nucleate at the same time,the transition temperature is so low that alloy elements in the regions previously occupied by pearlite bands diffuse faster than other regions,thus proeutectoid ferrite grains in these regions grow faster,regenerating the banded structure .
Study on Optimization Design of VSR Parameter for Large Welded Components
Authors: Zhang Xi , Dong Xue Wu , Ren Dai , Wang Yan Ting , Han Jian Hui , Yang Yan Yan
Published: August 2015

This article studies optimization design of Vibratory stress relief (VSR) technology parameter for large welded components. The test is carried through a large welded truss. It first analysis key factor of the influence on VSR technology effect. And then by modal analysis, we’ve got the natural frequency and natural modes of the specimen , The optimization design is based on residual stress distribution and natural modes of component for VSR process parameters. Test pieces are treated by vibration. before and after vibration, residual stress of the specimens is measured by the method of blind hole.The results showed that vibration mode is a key factor in determining the effect of VSR. Stress distribution is more complex for large welded components.As accordance by selecting a few of vibration modes, for VSR main technical parameters design, it can get enough vibration displacement in the areas and directions of component with residual stress. Thus we can have a good effects to relief welding residual stress.Three major parameters (Excitation frequency, excitation point, support points) are related with vibration mode. They are decided by selecting vibration mode. Excitation force is decided based excitation frequency as well as the size of the exciter eccentric , to get the right excitation force by adjusting the size of the exciter eccentric under the condition of the selected excitation frequency.
Prediction of Microstructure and Mechanical Properties of Weld Metal in Hybrid Laser-Arc Welding
Authors: Karkhin Victor A. , Homich Pavel N. , Ivanov Sergei Yu. , Michailov Vesselin , Panchenko Oleg V.
Published: August 2015

Calculation technique in order to reconstruct the 3D temperature field and predict the microstructure and mechanical properties of the weld metal in hybrid laser-arc welding is developed. The technique is based on the solution of the direct 3D temperature problem by a function-analytical method, the numerical solution of the inverse problem for the unknown parameters of a volume heat source, the employment of the known models for prediction of the microstructure and mechanical properties. The proposed calculation technique makes it possible to reduce considerably the total time for data input and solution. It is demonstrated with an example of butt hybrid laser-arc welding.
The Analysis and Improvement of the Influence Factors for the Fabrication of SMT Template and Laser Cutting Technique
Authors: Tang Yong
Published: August 2015

This paper briefly introduces the fabrication of SMT template and laser cutting technique,analyzes the factors that influence the SMT template fabrication and the laser cutting quality. Then it studies the improvement measures and methods through practical applications.
The Effect of External Voltage on Pulsed Electrohydrodynamic Printing
Authors: Yuan Xin , Ba Zheng Yu , Xiong Zhen Hua
Published: August 2015

Picoliter or femtoliter droplets generated with high frequency is very useful for many applications in different valuable fields, such as microarray generation, drug delivery or biochips. Pulsed electrohydrodynamic inkjet printing (Pulsed EHDP) is an advanced technology which is used for generating fine droplets in recent years. Apparently, the deposition frequency of droplets is a key parameter, and it is influenced by various factors. In this paper, the effect of duty cycle and voltage frequency on deposition frequency is investigated in the pulsation mode. A simple scaling law is proposed to demonstrate relationships between these two parameters and deposition frequency. Results show that volume of the liquid accumulated at the apex of the nozzle changes during the non-electric field period, which affects taylor cone deformation time and deposition frequency. High deposition frequency can be achieved by increasing the duty cycle up to 0.7, and choosing voltage frequency between 10Hz to 40Hz. These analysis is valuable for understanding Pulsed EHDP deeply and fabricating the micro/nanoapplications.
Study on Using Chenghe Fly Ash to Prepare 4A Molecular Sieve
Authors: Yang Jian Li , Du Mei Li , Zang Tian Qin
Published: August 2015

In recent years, with the rapid development of coal industry, a large number of coal fly ash has been produced, while the recycling rate of the ash is rather low. It is not only a waste of the precious land resources, but also makes environment suffering severe pollution. As an important kind of new material in the national economy, the demand for molecular sieve is growing. It is possible to synthesis molecular sieve using fly ash. The way is not only energy conservation and environmental protection, but also waste reclamation, according with the theme of the sustainable development.This study is to synthesize the molecular sieve with guide agent by the method of hydrothermal synthesis using Cheng He mining area in Shanxi province, which is on the basis of the analysis of chemical composition of fly ash. It is also to find a approach for the use of fly ash with subtly. Through XRD expert zing phase, SEM observing appearance, the characterizing results show that excellent performance molecular sieve of 4A can be synthesized at conditions: Calcined at 850°C and for 2 hours, then hydrothermal reacted with composition of reaction mixture 3Na2O:1Al2O3:2SiO2: 185H2O at temperature 90°C, crystallization time 6h with 5% guide agent.
Size Effect Mechanism on Foil Rolling Analyzed by Crystal Plasticity Finite Element Method
Authors: Chen Shou Dong , Liu Xiang Hua , Liu Li Zhong
Published: August 2015

A novel computational model is presented for the representation of polycrystalline grain structures and crystal plasticity finite element model are used to investigate size effect due to grain orientation and number of grains through the thickness, in term of activity of slip system, roll force and the scatter involved. It is predicted that increasing the number of grains through the thickness has detrimental effects on mechanical performance. It is clear from the current study that foil thickness significantly influences the deformation heterogeneity which leads to non-uniform distributions of strain and the inhomogeneous slip systems active in the cold rolled samples. It is found that the decrease of roll force and slip systems activities in surface grains are caused by the increasing of free surface grain effect when the thickness is decreased.
Method of Lines to Solve the Linear Temperature Field of LENS
Authors: Xue Chun Fang
Published: August 2015

This article introduces a semi-analytical numerical method ——method of lines(MOLs) to solve steady temperature field of Laser Engineered Net shaping (LENS). The main idea of MOLs is to semi-discretized the governing equation of thermal transfer problem into a system of ordinary differential equations (ODEs) defined on discrete lines by means of the finite difference method. The steady linear temperature fields of functionally graded materials were obtained using MOLs and the regularities of different temperature functions were also found. The effects of thermal conductivity coefficient under different formal functions on thermal temperature fields were analys. Numerical results showed that different material thermal conductivity function had obvious different effect on the temperature field.
Lightweight Foams with Open-Cell Structure Prepared by Pickering High Internal Phase Emulsions
Authors: Chu Ye Qian , Hua Ye , Zhu Yun , Zhang Sheng Miao , Chen Jian Ding
Published: August 2015

Lightweight foams with open-cell structure are prepared through water-in-oil Pickering high internal phase emulsions (HIPEs), whose density could be low down to 32.5 mg/cm3. The Pickering HIPEs are stabilized by copolymer particles, which also act as the building block for the resultant polymeric foams. The presence of toluene in the organic phase played a key role for the formation of well-defined interconnected pores in the resulting foams. The interconnectivity and the density of the foams could be tailored by varying the particle and electrolyte concentration in aqueous phase as well as the amount of toluene in the organic phase.
Performance of Ultra-High Strength Concrete Containing Different Types of Fibers
Authors: Li Wei Qin , Peng Yuan , He Xue Yun , Wu Xiong , Huo Liang
Published: August 2015

Influence of fiber on workability and mechanical property of ultra-high strength concrete (UHSC) were studied. Results show that, when amount of steel fiber (Equivalent diameter is 0.2mm; nominal length is 13mm; Tensile strength is 2850MPa )substituting fine aggregate is 120kg/m3, UHSC could have the best mechanical properties of 139.0MPa compressive strength, 18.0MPa flexural strength, and 10.0MPa Splitting strength; steel fiber cannot improve volume stability of UHSC.
Load Transfer Behavior of Cracking for Cement Concrete Pavement
Authors: Hu Chun Hua , Ma Xiao Zhou
Published: August 2015

In order to reduce the temperature and drying shrinkage cracking in cement concrete pavement, setting up cracks which becomes the weakest part of the cement concrete pavement. Load transfer behavior of cracking has a great influence on road performance and used lifetime in cement concrete pavement. The improvement of load transfer behavior of cracking is conducive to maintain effective load transfer between the pavement and to enhanced bearing capacity of pavement structure, also to reduce the damage of the structure, which is an important technical approach to extend the used lifetime of pavement. This paper describes the mechanism of load transfer and research status of crack, and points out the problems existing in the crack load transfer ability of research and development trend.
Mechanical Properties of Semi-Rigid Steel Frame-Braced Steel Plate Shear Wall
Authors: Shao Yong Song , Shao Feng Ru
Published: August 2015

Due to mechanical performances of brace and steel plate, mechanical properties of semi-rigid joints and its construction and installation, semi-rigid steel frame-braced steel plate shear wall system is proposed. Nonlinear static analysis with parameters (thickness of plate, type of brace, size of brace and the ratio of span to height) changed of a single-span and single-floor semi-rigid steel frame-braced steel plate shear wall system illustrates that braced steel plate shear walls contributes obviously to bearing capacity and lateral rigidity of semi-rigid steel frame. Also, the finite element analysis (by ANSYS) show that semi-rigid steel frame-braced steel plate shear wall system has excellent ductility.
Tuning the Pore Size of Monodisperse SBA-15 Spheres
Authors: Guo Cong , Liu Mou Zheng , Li Wen Zhi
Published: August 2015

A flexible, controllable and facile synthesis route was presented in the synthesis of spherical particles of mesoporous SBA-15 with diameter up to 28 nm, and particle diameter of 3-5 µm. The structures and morphology of these materials were characterized by powder X-ray diffraction (XRD), nitrogen adsorption analysis and scanning electron micrographs (SEM). The relationship between the porous property of silica and the weight ratio of starch to TMB were discussed. It indicates that the weight ratio of starch to TMB have a significant effect on the pore size, the surface area and also contribute to a narrow pore size distribution.
Waste Solid Byproducts of Microalgae Oil Made into Green Energy
Authors: Tsai Shu Yao , Hwang Bing Fang , Wu Tsung Chih , Lu Guan Yi , Lin Chun Ping
Published: August 2015

Microalgae have rich oil production under full photosynthesis, which reaches over 50 mass%. In addition, microalgae oil contains the prolific cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) that is usually refined for making health food or food additives. This study investigated Aurantiochytrium sp., which is a kind of microalgae, the oil of which is also refined for use in health food or food additives. The solid byproducts of Aurantiochytrium sp. oil are more than 20 mass%, discarded as rubbish. Fortunately, the solid byproducts have been found to contain a large amount of palmitic acid that exceeds more than 67 mass%, but it is difficult to transesterify from the solid byproducts of Aurantiochytrium sp. oil, such as the waste cooking oil or waste engine oil, which contain many impurities. Therefore, the sequences of saponification, reduction reaction, and acid-catalyzed reactions were conducted for the full process of transesterification in this study. Overall, we have successfully obtained more than 92 mass% transesterification rate from the solid byproducts of Aurantiochytrium sp. oil. The solid byproducts are waste turned into gold.