bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis Influence of Trailing Edge Modification on Aerodynamic Performance of Airfoils for Wind Turbine
Authors: Yuan Shang Ke , Li Ren Nian
Published: November 2012

The airfoil NACA 4412 commonly employed in wind turbines is modified by attaching a Gurney flap with length of 2% chord at its trailing edge and its remodeled form as well. The SIMPLE algorithm of finite volume method and software FLUENT are respectively used to carry out numerical computation of aerodynamic performances of above-mentioned three airfoils (including the un-modified one), so that their aerodynamic characteristics, pressure distribution on their surface, and streamline around them are obtained for different angles of attack. It is shown by the computation result that the modified airfoils will result in such a strong downwash effect that the pressure distribution on airfoil surface is remarkably altered, the lift coefficient and as well as the slope of lift-drag characteristic curve are increased, and meantime the airfoil stalling is greatly postponed.
Design and Implementation of Positioning System Based on Smart Space for Intelligent Wheelchair
Authors: Cai Jun , Zhang Shuang Long , Zhang Yi
Published: November 2012

In this paper, a positioning system based on smart space wireless sensor network platform is designed and a positioning method of RSSI-based wireless sensor network is studied. The intelligent wheelchair as a blind node in the smart space positioning system is used to collects adjacent the reference node coordinates and RSSI value. The blind node coordinates can be calculated by CC2431 location engine to achieve a wireless location. The test results show that: positioning error of the node is about 1 meter, so it has the potential to satisfy the application of the intelligent wheelchair indoor positioning.
Vehicle-Mounted Satellite Receiver Positioning System Based on the MEMS Gyro
Authors: Long Da Feng , Liu Jun , Sun Jun Li , Zhang Xiao Ming
Published: November 2012

To ensure that the vehicular satellite receiver get enough of their own real-time, accurate attitude information, considering the requirements low-cost, MEMS (Micro- Electron Mechanical System) inertial device is applied to the design of attitude positioning system for satellite receiver. Because of the low accurate degree, inertial navigation can’t fully used to help receiver to produce parameter. This paper undertakes to make use of parameter of velocity and attitude produced by laser gyro navigation system that installed in the head of the vehicle as MEMS inertial positioning system external combination information resource. And to integrate the MEMS inertial positioning system in the model of combining velocity and attitude by using Sage-Hausa adaptive filtering algorithm to evaluate the error of inertial navigation system on line, and rectify its calculating result so as to improve its degree of accurate. Through numerous analogical grounds vehicle operation experiments, the MEMS attitude positioning could reach the degree of accurate requirements by satellite receiver, therefore the testing program is feasible.
Research on Intelligent Vehicle Steering System via Improved Fuzzy-PID Control Method Based on RSDA
Authors: Dong Hui Fen , Li Feng , Gao Qing Ji , Dong Bao Lei
Published: November 2012

In order to improve the control accuracy and response speed of the intelligent vehicle steering system, a DC-motor controlled steering system using an IPC (Industrial personal computer) is designed. The hardware of the system is developed by analyzing the dynamic steering model. A new control method of Fuzzy-PID controller with RSDA (Rough Set Data Analysis) is proposed. Experimental results using the proposed control strategy show better performance and robust properties than the ordinary Fuzzy-PID.
Structural Failure Analysis of Shaft of Wobbly and Attrited Testing Equipment
Authors: Liu Ying Chun , Zuo Yun
Published: November 2012

In order to research the fatigue strength of gasket which is with new composite material in one plane, we designed and manufactured special testing equipment. The material of shaft of testing equipment is 30CrMnSi. In the experiment, the 30CrMnSi shaft was broken into two parts by suddenly. By structural analysis, static analysis and heat treatment analysis for shaft, we get the reason of fracture for shaft finally. The problem solved make the test goes well and can help design and manufacture testing equipment in the future.
Based on Flexible Automation Fixture of Siding Components of Assembly Craft Planning and Simulation
Authors: Wu Da Wei , Yuan Jun Chao
Published: November 2012

The research of assembly process design based on flexible automatic assembly process plays a critical role in improving the efficiency of aircraft assembly. it use the characteristics of flexible fixture reconfignrability to simplify assembly unit partition and make a kind of craft ideas apply to different assembly unit. Through wing assembly process research that obtains flexible automatic assembly assembly process can be versatile.
Theoretical Analysis for Force Transmissibility and Jump Phenomena of Duffing Spring Type Vibration Isolator
Authors: Zhang Xiao Long , Dong Ya Bin , He Yu Min
Published: November 2012

In order to study the common nonlinear characteristics of the vibration isolator, a single degree of freedom system with cubic restoring force is introduced to describe the nonlinear vibration isolation system in the paper and the harmonic balance method was applied to investigate the primary resonance near the natural frequency of the system. Based on Routh–Hurwitz stability criterion, it was clarified theoretically that the region surrounded by the curve of the vertical tangential points in the curve cluster of the primary resonance amplitude frequency characteristics was instable. In addition, the equations of the jump frequency and force transmissibility were derived. The calculated results showed that the jump, hysteresis, stable and instable phenomena would take place for the force transmissibility of the isolator system and the effect of high frequency components of the transmitting force was limited; the damping, coefficient of nonlinear restoring force and the excitation amplitude had an influence on the force transmissibility whose frequencies were in the region of the resonance frequencies but not on those whose frequencies were lower than the resonance frequencies, and only the damping would affect the force transmissibility whose frequencies were higher than the resonance frequencies. Finally, the equation of the start frequency, on the condition that the force transmissibility was less than 1, was presented.
Analysis of Cutting Zone Machinability during the Drilling of XCr18Ni8 Stainless Steel
Authors: Jurko Jozef , Panda Anton , Behún Marcel
Published: November 2012

This paper presents the conclusions of machinability tests on a XCr18Ni8 stainless steel. The content of this article also focuses on the analysis of selected basic indicators of steel machinability: quality of the processed surface. The results of the article are conclusions for working theory and practice for drillng of austenitic stainless steels. Based on the cutting tests, cutting speeds of 40 to 60 m/min, feed rate of 0.04 to 1.2 mm and screw drill carbide monolite.
A Carbon Fiber Reinforced Nylon 6 (CFRPA6) Composite Specialized for Military Field Cooking Task
Authors: Zhang Xiang Hong , Yang Han , Zhang Hao , Wang Chun Yang
Published: November 2012

In this study, nylon PA6 resin was filled with carbon fibers by employing the technique of mechanical alloying and utilizing the special properties of carbon fiber. The effects of carbon fiber on the mechanical property of the nylon PA6 were also studied. From the results, filling nylon PA6 resin with carbon fiber could effectively enhance the tensile strength, the elastic modulus, the flexural strength and the flexural modulus for the material. In addition, the material shrinkage was also significantly reduced. The enhancing effects varied as CF content changed. Through comparative experiments, the optimal proportion of the addition was determined. Replacing the conventional irony back pad of military outdoor pot by this composite would not only largely reduce the load and improve the motility for the soldiers, but also ensure a better battlefield adaptability and comfort.
Stochastic Response Surface Method with Enhanced Weighting Strategy
Authors: Sun Gao Rong
Published: November 2012

The weighted stochastic response surface method (WSRSM) has been demonstrated to be effective in improving the accuracy of the estimation of statistical moments and probability of failure (PoF) upon the stochastic response surface method (SRSM). However, it has been noticed that the weighting method in WSRSM may have little and sometimes negative impact on PoF estimation especially in the cases of low PoF. To address this issue, an enhanced weighting strategy is proposed that the weights of sample points are determined based on their importance not only to regression but also to PoF estimation. Specifically, relatively larger weights are assigned to points closer to the failure surface, which significantly accounts for the accuracy of PoF estimation. Comparative studies show that SRSM with the proposed weighting method outperforms WSRSM producing more accurate PoF estimation without incurring additional function evaluations.
Comparison of Transient Response of a Skin Panel under Uniform and Non-Uniform Thermal Loading
Authors: Yu Ling , Shukla Amit
Published: November 2012

This paper presents transient response of a skin panel under combined mechanical loading and provides a comparison of uniform and non-uniform thermal loading. A finite element model of a representative structural panel is used to evaluate the performance of an aero-structure subjected to severe aerodynamic heating and fluctuating pressure. This structure exhibits complex nonlinear response including thermal buckling and snap-through. In this study, uniform and non-uniform temperature distribution are used to understand the influence of spatial thermal distribution on the nonlinear response of the skin panel. It is shown that the parametric space snap-through boundary is significantly different for the two cases.
Effect of Sunroofs and Side Windows on Aerodynamic Characteristics of Transit Bus
Authors: Hu Xing Jun , Ren Feng Tao , Yang Bo , Guo Peng
Published: November 2012

In this paper, k-Omega turbulence model is applied in the numerical simulation of the transit bus, several typical working conditions of the transit bus with windows open at a speed of 10m/s are investigated, and a custom function Q is introduced to characterize the amount of ventilation of each window. The results show that, when the transit bus travels with windows open, the air always flows into the carriage through the middle and rear side windows of the transit bus, and circulates in the carriage and then flows out of the carriage through the front side window. When the bus travels with sunroofs open in leeward mode and side windows open, the amount of ventilation is the maximum. This working condition is the best one when taking both drag coefficient and the amount of ventilation.
Internal Combustion Engine and Fuel Cell Vehicles
Authors: Li Meng , Yi Zhou
Published: November 2012

In recent years, because of the energy crisis and the global warmth, new energyvehicles such like fuel cell vehicles are more and more popular, while there are still several problems in this technology, it is obvious that the conventional internal combustion engine play an important role in near future and FCEVs are the development direction of the future vehicles.
Influence of Lateral Interval on Aerodynamics Characteristics of Crossing Vehicles
Authors: Guo Li Xin , Zhang Hao , Zheng Tao , Li Jin Li
Published: November 2012

The investigations about vehicle crossing process mainly use numerical simulation methods and, moreover, the relevant investigation is quite less. In this study, a three- dimensional fluid simulation model was established. By moving mesh technique, the three- dimensional transient simulation for vehicle crossing process was finished. The aerodynamics characteristics of vehicle crossing process with different lateral interval distances were analyzed. The analytical results show that the smaller the lateral interval distance, the more the transverse thrust between two vehicles during the crossing process. During the whole crossing process, the lateral force shows itself with repulsion in the beginning and attraction in the end. When the lateral interval distance of crossing is very small, the air disturbance due to crossing not only makes large affection to the lateral force but also influence obviously the positive pressure area of the front car bodywork.
Multi-Object Control of Active Suspension Subject to Parameter Uncertainties under Non-Stationary Running
Authors: Zhang Li Ping , Guo Li Xin
Published: November 2012

Based on the building of non-stationary road surface excitation mode, a study on the active suspension control under non-stationary running condition was conducted using control, state feedback control strategy for linear systems with time-domain hard constraints was propose. The proposed approach was applied to design active suspension systems on the basis of a two-degree-of-freedom quarter car mode, Simulation results show that the proposed constrained controller can achieve a promising improvement on ride comfort, while keeping dynamic suspension deflections, dynamic tire loads and control forces within given bounds, even non-stationary running.
Study on Improved Method of Adding Stereotyping Board in the Automatic Pantyhose Packaging System
Authors: Li Pei Xing , Sun Yi Ze , Sun Zhi Jun , Wu Shi Qing , Huang Shuang
Published: November 2012

On the basis of analyzing folding method of the pantyhose available on market, this passage describes pantyhose automatic folding process in the automated packaging system, and focus on description of stereotyping board adding process. Then, it proposes a new adding stereotyping board method for the existing method, and describes the new method in detail. Finally, it compares the two methods, showing that the new method can solve the main problems in the former method, helping to improve the stability of automatic pantyhose packaging.
The Influence of Signal Acquiring Unit of Jacquard Control System on the Roughness of Carpet Surface in Textile Equipment
Authors: Sun Zhi Jun , Xu Yang , Sun Yi Ze , Li Pei Xing , Huang Shuang
Published: November 2012

Electronic jacquard control system is the core technology of tufted carpet equipment, whose dynamic characteristics determines the quality of tufted carpet surface(the roughness、the level of loop transition phenomenon).In this paper, the structure of jacquard control system is analyzed. And the concept of roughness of carpet surface is given. Its evaluation model is established. Through analysis of structure, we point out that the key factor affecting the quality of carpet surface is signal acquiring unit which is investigated in this paper. We analyze the characteristics of system and the quality of the carpet surface, also establish the model of relationship between the synchronous sampling frequency of stepper motor and the height of carpet loop. Using this simulation model, we get the optimal synchronous sampling frequency of stepper motor to ensure the quality of carpet surface, also provide a theoretical basis for the design of control system.
Study on Three-Motor Synchronous System of Fuzzy Active Disturbance Rejection Control
Authors: Tang Lin , Liu Xing Qiao , Zhu Li Ting
Published: November 2012

Fuzzy active disturbance rejection controller of three-motor synchronous system is proposed in this paper, which could adjust the parameters automatically by using the inferential capability of fuzzy control. Double channels compensation of extended state observer is used to estimate and compensate the total disturbance of the system and the coupling between speed and tensions, thus an approximate linearization and deterministic system is obtained. The results of experiments prove that the control system has better performances of dynamic and static characteristics, stronger anti-interference ability and better robustness than the traditional PID control system, realizing a better decoupling control of speed and tensions.
Experimental Study of Gravity Heat Pipe with ECT
Authors: Liu Qian , Zhou Lei , Cao Li Ping , Wang Ze Pu , Liu Shi
Published: November 2012

Gravity heat pipe’s interior phase change and heat transfer mechanisms are hardly to research, yet significant for strengthening heat transfer and enhancing energy utilization. This paper reports experimental study on the reconstructed images and concentration measurement of liquid (ethanol) at condensation section of gravity heat pipe with electrical capacitance tomography (ECT). Furthermore, signals’ noises collected by ECT have been reduced with Hilbert-Huang transform (HHT). Finally, reconstruction images have been compared with M. Shiraish’s model, and ECT has provided alternative experimental platform for the research of gravity heat pipe’s mechanisms.
Compression-after-Impact Testing of CFRP Laminates Subjected to Simulated Lightning Damage Monitored by Acoustic Emission
Authors: Kwon Oh Yang , Shin Jae Ha
Published: November 2012

CFRP laminates made of nano-particles-coated carbon fibers and damaged by a simulated lightning strike were tested under the compression-after-impact (CAI) mode, during which the damage progression was monitored by acoustic emission (AE). The effects of nano-particles coating on the degree of lightning-damage and the mechanical integrity of composite structures damaged by lightning strikes have been evaluated in terms of AE activities.
Multidisciplinary Design Optimization of Driving Axle Housing Using Sparse Grid Approach
Authors: Ma Shi Lei , Li Fang Yi , He Yang , Xu Qing Zhong
Published: November 2012

In order to improve the engineering performance of lightweight design on the driving axle housing, lightweight, structural mechanics, fatigue strength and dynamics are applied in the multidisciplinary design optimization. Firstly, finite element model of driving axle housing was established and its accuracy was verified through bench tests. Secondly, driving axle housing system was divided into multiple sub-discipline systems and design variables of multidisciplinary lightweight design were determined, in order to solve the problems of large amount of data transmission and complex calculation, sparse grid approach was used to establish high accuracy approximate model of each discipline. Lastly, mass of driving axle housing and difference values of first six order modal frequencies before and after lightweight design were optimized through Non-dominated Sorted Genetic Algorithm-Ⅱ, the Pareto optimal solution set was obtained. In optimization results, masses of driving axle housing are all decreased compared to the initial design, meanwhile, the dynamic performance, structural static intensity and fatigue life are all ensured.
Effect of Mineralizer (KNO3) on the Structural and Optical Properties of h-MoO3 Nanocrystals
Authors: Chithambararaj A. , Bose Arumugam Chandra
Published: November 2012

Single phase hexagonal molybdenum oxide (h-MoO3) nanocrystals were successfully synthesized by solution based chemical precipitation method. The effect of mineralizer (KNO3 salt) on hexagonal phase, crystallite size, and surface morphologies of MoO3 was investigated by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) analysis. The XRD result indicates that the diffractograms exhibit characteristic hexagonal phase of MoO3. From the line broadening analysis, the average crystallite size was calculated and estimated. A less crystallite size of 34 nm was obtained in the presence of mineralizing agent KNO3 in comparison to without mineralizer (46 nm). The particle exhibits rod like morphology with perfect hexagonal cross-section and well faceted top and side surfaces. Further, the thermal and optical properties were studied by thermo gravimetric analysis (TGA) and diffuse reflectance spectroscopy (DRS) measurements. The weight loss due to decomposition of intercalated water and ammonia were observed. By TGA analysis, the mineralizer assisted sample shows higher phase stability with the phase transition temperature of 520 °C due to the incorporation of K+ in MoO3 structure. The optical band gap energy was calculated using Kubelka-Muck function and the values were found to be 3.11 eV and 2.97 eV for KNO3 assisted and non-assisted MoO3 samples respectively. The observed increase in optical band gap (Eg) for h-MoO3 synthesized in the presence of KNO3 was attributed to the size dependent optical properties.
Refractive Index Tailoring of Poly(methylmethacrylate) Thin Films by Embedding Silver Nanoparticles
Authors: Goyal Alisha , Rozra Jyoti , Saini Isha , Sharma Pawan K. , Sharma Annu
Published: November 2012

Nanocomposite films of Poly (methylmethacrylate) with different concentration of silver nanoparticles were prepared by ex-situ method. Firstly, silver nanoparticles were obtained by reducing the aqueous solution of silver nitrate with sodium borohydride then Ag-PMMA films were prepared by mixing colloidal solution of silver nanoparticles with solution of polymer. Thin solid films were structurally characterized using UV-VIS spectroscopy and TEM. The appearance of surface plasmon resonance peak, characteristic of silver nanoparticles at 420 nm in UV-VIS absorption spectra of Ag-PMMA films confirms the formation of Ag-PMMA nanocomposite. TEM showed Ag nanoparticles of average size 8 nm embedded in PMMA matrix. Analysis of absorption and reflection data indicates towards the reduction in optical band gap and increase in refractive index of the resulting nanocomposite. The synthesized Ag-PMMA nanocomposite has been found to be more conducting than PMMA as ascertained using I-V studies. The decrease in band gap and increase in conductivity can be correlated due to the formation of localized electronic states in PMMA matrix due to insertion of Ag nanoparticles. The PMMA thin films with dispersed silver nanoparticles may be useful for nanophotonic devices.
Rietveld Refinement and DC Conductivity of Na0.5K0.5NbO3 Ceramics
Authors: Sindhu Monica , Ahlawat N. , Sanghi Sujata , Agarwal Ashish , Ashima A. , Kumari Rekha , Ahlawat Navneet N.
Published: November 2012

Potassium Sodium Niobate, Na0.5K0.5NbO3 is a promising base material for lead free piezoceramics. The polycrystalline sample Na0.5K0.5NbO3 was synthesized using solid state reaction method. The crystal structure and phase purity was studied by XRD and analysed using Rietveld refinement method. Good agreement was observed between the observed and calculated patterns in Rietveld refinement. The refinement inferred orthorhombic crystal structure with Amm2 space group. The impedance spectroscopy of the sample was performed in frequency range 10 Hz to 7 MHz in temperature range 573K to 703K. The activation energy was obtained to be 0.67eV from the reciprocal temperature variation of dc conductivity which follows the Arrhenius law.
Synthesis of TiO2 Film for Dye-Sensitized Solar Cells
Authors: Singh Harjeet , Prakash Shejale Kiran , Panjiar Himanshu , Daniel Brainerd S.S.
Published: November 2012

Mesoporous solid TiO2 film (2-50nm) offering large specific surface area and well connected cavities have been researched extensively in the last decade, aiming to enhance photo-conversion efficiency in the dye-sensitised solar cells (DSSCs). The efficiency of DSSCs is highly sensitive to surface morphology, crystallinity and porosity of the TiO2 film which are in turn dependent upon processing temperature. Multilayered porous TiO2 films were synthesised under different temperature regimes using sol-gel method in combination with spin coating. The influence of temperature variation on the films morphology, crystallinity, and its interfacial adhesiveness to the substrate was studied. A modified method of pre-curing temperature was employed, in order to attain firm adhesiveness of the film to the Fluorine-doped Tin Oxide (FTO) glass substrate. The films prepared by different pre-curing temperature protocols were incorporated into DSSCs for evaluating the affect of varying temperature on photo-conversion efficiency of the cells.
Fe-P Soft Magnetic Properties of Iron for A.C. Applications
Authors: Chaurasia S.K. , Prakash Ujjwal , Misra P.S. , Chandra K.
Published: November 2012

Silicon steels and ferrites dominate soft magnetic materials. However, Soft magnetic materials using powder metallurgical techniques are gaining wide spread use in motor, compressors and other rotating devices. High-density Fe-P soft magnetic materials have been developed using hot powder forging route. It was observed that phosphorous addition (ranging from 0.30P-0.80P) enhances the soft magnetic properties of iron for AC applications. This new soft magnetic material offers many manufacturing advantages. Because of its low eddy current loss, it has good high frequency magnetic properties comparable to other soft magnetic materials. Also, it has been observed that phosphorous addition improves the final density of the resulting product.
Thermodynamic Rationalization of the Microstructures of CrFeNi & CuCrFeNi Alloys
Authors: Singh Anil Kumar , Subramaniam Anandh
Published: November 2012

In high entropy alloys (HEA) a disordered solid solution is entropically stabilized, in competition with possible intermediate compounds or phase segregation. It has been reported that disordered solid solutions are stabilized by the presence of five or more elements in the alloys; typically in an equimolar ratio. In the current investigation, the effect of Cu addition on the microstructure of CrFeNi alloy is rationalized by Gibbs free energy calculations. Two phase (both are FCC) solid solution are seen to form in CuCrFeNi alloy. The alloys are prepared by induction melting and are characterized by x-ray diffraction and scanning electron microscopy (in as-cast and annealed state). Enthalpies of mixing were calculated using Miedema's model and the regular solution model. Entropy of mixing is determined by using the Boltzmann's hypothesis.
Fabrication and Characterization of Aluminium Matrix Composites by High Velocity Oxy-Fuel Thermal Spraying
Authors: Singh Gagndeep , Vohra Hitesh , Kaur Manpreet
Published: November 2012

The High Velocity Oxy-fuel (HVOF) spray technique has been used by many researchers to deposit composite coatings, but there is less available literature discussing the fabrication of bulk metal matrix composites by this technique. In the current study, aluminum matrix composites with dispersions of alumina (Al2O3) and silicon carbide (SiC) particulates are fabricated by HVOF spray technique. The study comprises the steps of providing the substrate, preparing a mixed powder comprising a first metal powder as a matrix and a second metal powder comprising a ceramic and selected as reinforcement. The detailed procedures to prepare the bulk by using the same are reported. An in-depth characterization of the composite formed has been performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Hardness of the composite formed is measured on Vickers microhardness tester. This study showed the possibility of fabricating bulk metal matrix composites of larger size by HVOF spray technique.
Mechanical Properties and Tensile Fracture Mechanism of Rheocast A356 Al Alloy Using Cooling Slope
Authors: Das Prosenjit , Samanta Sudip K. , Ray Tapan , Venkatpathi B.R.K.
Published: November 2012

A356 aluminium alloy has a wide applicability in the manufacturing of automotive parts. Cooling slope (CS) rheocasting process has been used in the present work to produce A356 billets having near spherical morphology of primary Al phase. Absence of dendritic primary phase, observed in case conventionally cast A356 alloy, and finer distribution of secondary eutectic Si phase within the matrix establishes the usefulness of the CS casting route. Near spherical primary phase in the rheocast alloy ensures better strength, elongation properties and structural integrity in the produced billets. The liquid melt is allowed to flow through the cooling slope after pouring at 6500C. Rapid heat exchange between the flowing melt and slope wall and the atmosphere facilitates heterogeneous nucleation of α-Al phase on the cooling slope wall. Shear driven flow of the solidifying melt is found responsible for separation of α-Al phase from the slope wall and generation of nearly spherical morphology of the primary phase in the microstructure. Grain refiner addition in the melt leads to enhance the primary α-Al percentage in the microstructure and also aids to the improvement of degree of sphericity and reduction of spheroid size. So, grain refining helps to improve the strength, elongation and fracture properties of rheocast billets further.
RETRACTED: Grain Growth Kinetics of Accumulative Roll Bonded AZ61 Alloy
Authors: Nayaka H. Shivananda , Chaudhari Gajanan P. , Daniel B.S. Sunder
Published: November 2012

Retracted article: A detailed study was performed on the grain growth kinetics of ultrafine-grained AZ61 magnesium alloy produced by accumulative roll bonding by carrying out isothermal annealing treatments on the roll bonded samples. Annealing treatments were carried out in the temperature range 423 to 573K for 2 to 120 minutes. As the annealing time and temperature increased, the grain size increased. The effect of annealing temperature and time, on the grain growth can be well explained by the kinetic equation and Arrhenius equation. Based on the experimental results of grain growth during annealing treatments, the grain growth exponent and the activation energy for grain growth were determined. The grain growth kinetic parameters were compared with other magnesium alloys processed by various methods.
Mechanical Properties of Al6061 Processed by Equal Channel Angular Pressing
Authors: Sahai Ankit , Sharma Rahul Swarup , Raj K. Hans , Gupta Narinder Kumar
Published: November 2012

The severe plastic deformation (SPD) is an effective approach for producing bulk nanostructured materials. The Equal Channel Angular Pressing (ECAP) is the most efficient SPD solution for achieving ultra-fined grained (UFG) material as billet undergoes severe and large deformation. The process parameters of ECAP (Channel Angle, angle of curvature, friction, number of passes, etc) influences major impact on the properties. In present work, the ECAP process is performed by pressing a specimen through a die consisting of two intersecting channels meeting at an angle φ and outer corner meeting at an angle ψ. Experiments with a circular specimen of Al6061 were conducted to investigate the changes in mechanical properties upto 2 passes. 3-D finite element simulations were also performed using metal forming software FORGE to study the evolution of strain in the specimen during the ECAP process. Simulation results were investigated by comparing them with experimental measured data in terms of load variations. The present work clearly shows that ECAP caused accentuated increase in Al6061 hardness and tensile strength during multi-pass processing. This study is beneficial in developing high quality, high strength products in manufacturing industry on account of its ability to change microstructure of materials.
Effect of Distance between Passes in Friction Stir Processing of Magnesium Alloy
Authors: Govindaraju M. , Prasad K. Rao , Chakkingal Uday , Balasubramanian K.
Published: November 2012

Friction stir processing is applied for property improvement of cast alloys for last two decades and many developmental studies were carried out in this topic on various alloys. In the current work, friction stir processing was carried out on rare earth containing magnesium alloy AE42. This alloy was specially developed for automobile application as it has better creep resistance than commercial magnesium alloys. Multi-pass Friction Stir Processing was carried out with varying the distance between passes from 0.5 mm to 2.5 mm using 12 mm shoulder diameter tool. Pin was with conical (tapered) and flat configurations with 3 mm height. After processing, the resultant mechanical and metallurgical properties were evaluated. Microstructure was refined to 5 micron and the secondary phases were made in to tiny pieces of 0.5-1 micron and evenly distributed in the matrix. Continuous network of grain boundary which is reason for poor mechanical properties was eliminated. Mechanical properties were improved by 30%. The variation of mechanical properties of processed material with respect to variation of distance between passes was negligible from 1 mm to 1.5 mm for flat pin tool.
Effect of Deposition Parameters & Molybdenum Percentage on Nickel-Molybdenum Alloy Coatings
Authors: Kamlesh Joshi , Amarendra Hassan Jayaraj , Chaudhari Gajanan Prabhakar , Nath Sameer Kumar
Published: November 2012

The use of Potassium-phosphate baths for the alloy deposition of Nickel–Molybdenum is recently proved equally good as Sodium-citrate baths. The coatings so obtained from Potassium-phosphate baths were examined for atomic weight percentage of Molybdenum. The variation in weight percentage of Molybdenum was obtained by varying different plating parameters like - molar ratio, current density range, and potential range. The observed co-deposited Molybdenum Atomic percentage variation in alloy was investigated for grain size, porosity in structure and surface roughness. The results revel that Molybdenum Atomic percentage in the Nickel–Molybdenum alloy has effect on porosity and surface roughness. It was also found that root mean square value of surface roughness was not only affected by the Molybdenum Atomic percentage but also by potential at relaxation time (TOFF) potential.
Preparation and Characterization of Thermal Spray Coating of Glass Microspheres on Metal Substrate
Authors: Gupta Gaurav , Mishra Srimant Kumar , Mantry Sisir , Satapathy Alok
Published: November 2012

Plasma spray technology utilizes the exotic properties of the plasma medium to effect physical, chemical or metallurgical reactions to produce new materials or impart new functional properties to conventional materials. It is in fact a process that includes melting, rapid solidification and quenching taking place simultaneously. As for the coating materials, it is well understood that for a number of unique application, spherical particles are preferred over irregular ones due to low surface area to volume ratio, high density, free flowing ability and close sizing etc. In view of this, the present paper reports on the preparation of glass microspheres coatings on mild steel substrate using plasma spray technology. An 80 kW atmospheric plasma spray set up is used for spraying purpose. Solid glass micro-spheres of average sized 100 micron are used as the coating materials which are deposited at four different power levels on mild steel substrate. The coatings are characterized in terms of their thickness, hardness, density and porosity. The coatability of glass micro-spheres on mild steel is assessed by evaluating the coating deposition efficiency. Different phases present in the coating are ascertained using X-ray diffractography.
A Study on Ni-P and Ni-P-ZnO Composite Coatings Developed by Electroless Technique
Authors: Sharma Sarika , Sharma Sulaxna , Agarwala Pooja , Garg Rajnish , Gopinath P.
Published: November 2012

A new processing concept has been developed to produce nano structured metal matrix composite coatings. Electroless coatings of Ni-P and composite Ni-P-ZnO were developed by co-deposition process on mild steel substrates. Ni-P-ZnO coatings were prepared using conventional route i.e., ZnO particles of ~ 20 μm with average diameter were added to the bath (900C, pH ~9.0) and kept in suspension by stirring. Uniform and grayish bright coatings were observed. The coatings were heat treated at 400°C for 1h in argon atmosphere to attain crystalline nature of coating. The as-synthesized and heat treated Ni-P and composite Ni-P-ZnO coatings were characterized by XRD, FESEM and AFM.
A Comparative Study of Cavitation Erosive Behaviour of 23/8N Nitronic Steel and 13/4 Martensitic Stainless Steel
Authors: Selokar Ashish , Goel D.B. , Prakash Ujjwal
Published: November 2012

Abstract: Hydroturbine blades in hydroelectric power plants are subjected to erosion. Currently these blades are made of 13/4 martensitic stainless steel (ASTM grade A743). This steel suffers from several maintenance and welding related problems. Nitronic steels are being considered as an alternative to martensitic stainless steels since they have good weldability. In present work, erosive behaviour of 13/4 Martensitic and Nitrogen alloyed austenitic stainless steel (23/8N steel) has been studied. Cavitation erosion tests were carried out in distilled water at 20 KHz frequency at constant amplitude. Microstructure of eroded surface, mechanical properties and erosion rate were characterized. It was observed that 23/8N steel possesses excellent resistance to erosion in comparison to 13/4 martensitic steels. 23/8N steel showed good hardness coupled with high tensile toughness and work hardening ability, leading to improved erosion resistance.
Effect of Mg Substitution on Microwave Absorption of BaFe12O19
Authors: Kumar Abhishek , Agarwala Vijaya , Singh Dharmendra
Published: November 2012

The Magnesium substituted barium hexaferrites were prepared by sol-gel auto-combustion method according to the molecular formula BaMgxFe(12−x)O19 (x=0, 0.5 and 1). The crystalline structure, morphology, complex permittivity, and complex permeability were measured with X-ray Diffraction (XRD), Field Emission-Scanning Electron Microscopy (FE-SEM) and Vector Network Analyzer (VNA) respectively. From XRD study, the formations of single phase ultrafine particles have been confirmed. The XRD analysis showed that variation in lattice parameter with change in x value. The FE-SEM study shows that synthesized particles have hexagonal morphology. The minimum reflection loss of -24.86 dB at 9.04 GHz was found with the increase in band width at x=1, which suits its application as RADAR absorbing materials.
New Metallic Detergents for Lubricating Oils
Authors: Shi Yong Gang , Wang Shuai , Li Zi Cun , Mei Lin , Sun Ping
Published: November 2012

To improve anti-oxidation, anti-wear and extreme-pressure performances of metallic detergents, the over-based substrates of two detergents were modified by partial neutralization with sulfur and phosphor containing carboxylic acids. In this way, two modified detergents were prepared. The non-modified and modified detergents were evaluated by four-ball tester and thermogravimetric analyzer. The results have shown that the modification enhances anti-oxidation and extreme-pressure performance of the detergents without affecting their dispersing ability and anti-wear behavior obviously.
Modeling and Calculation of Electron Transmission Coefficient from Printed CNT Film to Vacuum
Authors: Zhang You Lin , Yang Wan Quan , Ma Hua Li , Zeng Fan Guang
Published: November 2012

The conducting chains in printed CNT film were considered as (MI)iV or (MI)i-1MV configuration. The transport and field emission of electrons in printed CNT film can be considered as tunneling conduction. The transmission coefficient of an insulator barrier surrounding a CNT was calculated via quantum mechanical principle. When an electric field is applied to CNTs, the barrier of residual was considered as a group of rectangular potential barriers. The total transmission coefficient for a residual-covered emitter during emitting was solved numerically from the product of the two transmission coefficient for the potential barriers of residual and the vacuum level.
Preparation and Research of Iatric Fiber with Far Infrared Ray Radiation Function
Authors: Yao Xiao Feng , Wang Jian Ping , Li Dong Ping , He Tin Ting
Published: November 2012

Many kinds of jewelries and ceramic could emit far-infrared rays (FIR) when subjected to the body temperature. Reported works show that FIR have some effects on human body, especially on skin, blood circulation, and skin cell vitalizing. In this study, we tried to use pearl and Panax Notoginseng powder in nanoscale as ingredients to add in viscose fiber and investigate whether this new fiber has benign regulative action on human microcirculation. SEM scanner was used to study the distribution and mean diameter of the particles in fiber. 30 graduates were chosen as subjects and divided into two groups. They used the arm sleeves either impregnated or not impregnated with pearl and Panax Notoginseng powder for 30min/an hour, and were tested the nail-fold microcirculation change. Experimental data showed a much larger improvement of nail-fold microcirculation while using arm sleeves impregnated with pearl and Panax Notoginseng powder than pure cotton arm sleeves. Experimental results are provided to demonstrate the new type iatric fiber with pearl and Panax Notoginseng powder has the capability of biological modulation.
A Case Retrieval Method in Case-Based Fixture Design
Authors: He Yun , Zhang Fa Ping , Sun Zhan Chun , Gao Bo , Han Juan
Published: November 2012

Most fixture design process are based on the reuse of the previous design knowledge and experience, in this paper, we use a case-based design (CBD) method to design fixture. Based on the analysis of various CBD methods, we found that most methods used to calculate the similarity between new part and cases are too single, so we put forward a method combining the semantic attribute similarity and the shape similarity together, use a weighted algorithm to calculate the similarity. Using this method, we designed a Fixture Design System on CATIA V5 R19, and use this system to retrieve and design fixture, the retrieved results are more close to the new part and reusable, the design process is more efficient.
Research of System Identification for Ni/MH Battery State of Charge Based on a Short Sequence and Multi-Sample Process
Authors: Long Jian Xiong , Yu Lin Ming , Chen Shi
Published: November 2012

In the battery state of charge of a systematic analysis, the observed data has a property that is the direction of time t (referred to as vertical) for a limited length, and number of samples obtained by N (called horizontal) for the infinite data set , it is called as a short sequence and multi-sample time series. By studying the characteristic of this time series, a new system identification method has been proposed, and the system identifiability for this process has been demonstrated. Through practice simulations, a satisfactory application results have been obtained. This feature of the time series identification problem is the same in other areas have a certain reference value.
A Low Frequency Permanent Magnet Passive Vibration Isolator
Authors: Li Qiang , Xu Deng Feng , Hu Jin Chun , Hao Liu
Published: November 2012

Magnetic suspension vibration isolators have attracted significant attention in the field of semiconductor industry and high precision equipments. However, it is impossible to levitate an object by only permanent magnet due to instability of permanent magnets. It needs a guide device or active control to hold the magnetic suspension passive vibration isolator (MSPVI) at equilibrium position. In order to overcome the instability of the permanent magnets, the linear bearing, rubber O-ring and rubber membrane are applied in the MSPVI. The transmissibility of the MSPVI was calculated and subsequently measured. The experimental results show that the MSPVI can achieve low natural frequency with the help of the rubber membrane which is superior to the linear bearing and o-ring. Beside, the vibration isolating performance of the MSPVI is measured. The experimental results reveal that the MSPVI achieves the lowest resonant frequency when the load capacity of the MSPVI reaches maximum value.
Different Activities of Osteoblast and Bacteria on a Nanostructured Titanium Surface for Dental Implant
Authors: Zheng Yan Hua , Li Jin Bo , Liu Xuan Yong , Sun Jiao
Published: November 2012

Insufficience of osteogenesis and antimicrobial effect have been still impacted the long term clinical success rate of dental implants. A nanostructured titanium surface prepared by hydrothermal treatment with H2O2 was evaluated on its osteoblastic viability and antibacterial effect. Samples were divided into 2 groups: untreated pure titanium surface (Ti) and a nanostructured titanium surface (NT). The antibacterial activities against S.mutans and C.albicans were measured by film applicator coating assay, as well as the live/dead bacteria stain. The osteoblastic viability was investigated by SEM and MTT assay. Results showed that the active microbia on NT was reduced at 24h (P<0.05) significantly according to the live/dead bacteria stain and film applicator coating assay, which could also enhance the osteoblast viability. Therefore, a nanostructured titanium surface exhibits good antibacterial activity on S.mutans and C.albicans, and promoting osteoblast viability, which will be a potential kind of dental implant material.
Evaluation of the Geo-Mechanical Parameters of the Interface between Asphalt Concrete and Sand with Applying Direct Shear Test and Numerical Modeling
Authors: Tajdini Milad , Rostami Ali , Karimi Mohammad M. , Taherkhani Hasan
Published: November 2012

Asphaltic concrete has been used as waterproofing core in embankment dams, since 1948. In this application, the asphaltic core is surrounded by granular filter materials. The interaction of the asphaltic concrete and the granular materials has not been sufficiently investigated. In this paper the mechanical behavior of the interface between a natural smooth sand filter and asphaltic concrete at different levels of normal stresses and a constant shear strain rate has been studied. Small scale direct shear test has been conducted in this study, in which the shear surface is considered as the interface. Asphalt concrete specimens used in the shear test were cut in square shape (10×10×2.5 cm) from cylindrical specimen compacted by modified marshal compaction method. According to the direct shear test the interface constitutive parameters (cohesion, friction angle and shear stiffness) have been obtained. Using the parameters obtained from the direct shear tests, the numerical model of the test by applying FLAC3D Finite Difference software has been made, for which the Mohr-Coulomb constitutive parameters of the asphalt concrete have been obtained from back analysis using ABAQUS Finite Element software according to the conducted Marshal Test results on the asphalt. Utilizing the obtained parameters for both asphalt and interface, the normal stiffness of the interface has been extracted by back analysis with applying FLAC3D. It is shown that the shear stiffness and shear yield strength of the interface between sand and asphalt concrete, and the normal stiffness of the interface increase with increasing the normal stress level since driving direct shear test. The results of this study can help solving numerical problems of the interaction of asphaltic core and surrounding soil with considering more precise interface constitutive value, especially in the embankment dams with asphaltic core, which normal stress distribution on the asphaltic core varies through the different depths in the dam due to the hydrostatic pressure.
Shear Resistance of Non-Reinforced Oil Palm Shell Concrete Beams
Authors: Chin Mei Yun , Leong Lau Teck
Published: November 2012

The test results of reinforced concrete beams cast with Oil Palm Shell (OPS) in shear mechanism are presented. It was found that the shear mechanism in Oil Palm Shell Concrete (OPSC) beams is similar in nature to those found in normal weight concrete (NWC) beams. Comparative studies carried out on variables affecting the shear mechanism indicate OPSC beamsproduce similar shear strength to NWC beams.