bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on Post-Yield Behavior of Cortical Bone
Authors: Sharma N.K. , Nayak J. , Sehgal D.K. , Pandey R.K.
Published: November 2012

Complex hierarchical assembly and presence of large amount of organics and water content are responsible for enough amount of plasticity in bone material. Plastic properties are not only important to assess the various changes and fracture risk in bone but also for the development of better bone implants and joint replacements. The present study is focused on the post-yield behavior of cortical bone. The plastic properties of goat femoral and tibiae cortical bone were assessed and compared in terms of plastic modulus (H), tangent modulus (Et), plastic work (Wp) and plastic strain (εp) using uniaxial tensile test. Both femoral and tibiae cortical bone were found to be having similar post-yield behavior and significant stiffness loss was observed in both the bones during plastic deformation. The value of plastic modulus for femoral cortical bone was found to be 1.2 times higher as compared to the corresponding value for tibiae cortical bone. This shows higher hardening rate for femoral cortical bone. It was also observed that femoral bone requires higher energy during plastic deformation until fracture as compared to tibiae cortical bone.
Research on Airplane BOM Management Based on Single Source of Product Data
Authors: He Li Na , Ming Xin Guo , Kong Fan Bing , Zuo Huai Liang , Yao Zhen Hua
Published: November 2012

The core of airplane lifecycle data management is BOM management in the product lifecycle. Aiming at the problem of nonunique data source existing in airplane lifecycle, the paper proposes the airplane BOM management hierarchical system framework based on Single Source of Product Data ( SSPD) and the corresponding technology. The logical unified SSPD is constructed to guarantee the uniqueness of lifecycle data. According to the diversity and complexity of airplane，customer options management and BOM management based on SSPD, are discussed emphatically in the context.
Application of Fuzzy Adaptive Fusion Algorithm in INS/BNS/GPS Integrated Navigation System
Authors: Ren Yan , Xu Duan , Yue Wei Feng
Published: November 2012

The problem of data fusion based on filter is studied for an integrated inertial navigation system / Beidou navigation system / global positioning system (INS/BNS/GPS) with uncertain noise and conditionality of using GPS. The integrated navigation system can be divided into two integrated navigation subsystems (INS/BNS and INS/GPS). The signals from GPS and BNS receivers are easy to be disturbed, so filter is used to estimate the subsystem errors which are transmitted to fusion center online. Then data fusion is carried out by using the fuzzy fusion algorithm. Simulation results show that the algorithm can improve the accuracy and stability of navigation system.
Studies on Aerodynamic Characteristics of Dump Diffusers for Modern Aircraft Engines
Authors: Sathyan P. , Srikanth S. , Dheepan I. , Arun M. , Aswin C. , Sanal Kumar V.R.
Published: November 2012

The geometrical optimization of dump diffusers are extremely demanding as the flow fields and stress fields are very complex and must be well understood to achieve the required design efficiencies. In this paper parametric analytical studies have been carried out for examining the aerodynamics characteristics of different dump diffusers for modern aircraft engines. Numerical studies have been carried out using SST K- ω turbulence model. This code solves SST k- ω turbulence equations using the coupled second order implicit unsteady formulation. In the numerical study, a fully implicit finite volume scheme of the compressible, Reynolds-Averaged, Navier-Stokes equations is employed. We concluded that in addition to the dump gap ratio, the aerodynamic shape of the flame tube case and the other geometric variables are also need to be optimized judiciously after considering the fluid dynamic constraints for controlling the pressure recovery and the losses.
Dynamic Impact Behavior of Water Droplet on a Superhydrophobic Surface in the Presence of Stagnation Flow
Authors: Mohammadi Morteza , Moghtadernejad Sara , Graham Percival J. , Dolatabadi Ali
Published: November 2012

The following study investigates splashing of impinging water droplets on superhydrophobic surfaces with and without the presence of a stagnation flow. Droplets were accelerated by either gravity or gravity and co-flow. By changing the height and the air flow velocity different combinations of stagnation flow and droplet velocity were created. The spreading diameter, spreading velocity and contact time were studied for different air and droplet speeds. It was clearly observed that for a fixed impact velocity (i.e. constant Weber number), the presence of the stagnation flow promotes splashing and formation of satellite droplets. Consequently, for the co-flow droplet impact experiments, the mass of the recoiled droplet is significantly smaller than that of the impinging droplet in still air.
Study of Numerical Evaluation about Kinestate of Mixed Particles in Rectilinear-Flow Pneumatic Conveyance
Authors: Li Yi , Chen Shui Sheng , Yang Guang You
Published: November 2012

The effect of rectilinear-flow upon kinestate of particles had been investigated by numerical calculation about mixed particle swarm in the process of pneumatic conveyance. The effect of kinestate upon pressure loss, particles position and velocity has been analyzed. The air velocity is 20m/s, and the length of the pipe is 4m. It was found that most particles are accumulated at the bottom of the pipe, and particles velocity tends to stabilize at the top. Stopping would probably be formed at the bottom if the energy of air stream is not enough. In addition, bottom of pipe exceeds top in the number of collision between particles because of the accumulation of particles, so pressure loss at the bottom is much more than that of the top.
Range Prediction and Trajectory Correction of Long Range Rocket with Attitude Stabilization
Authors: Li Ke Yong , Xiong Fen Fen , Zhang Cheng , Chen Shi Shi
Published: November 2012

The dispersion of long range rocket is significantly suppressed by the attitude stabilization in the boost phase. However, the attitude stabilization system cannot govern the propellant impulse error and mass error, which induces large dispersion in the longitudinal direction. Therefore, it is necessary to conduct range correction in the post-boost phase of flight trajectory. A range prediction method based on the elliptic ballistic theory is proposed in this paper. Elliptic ballistic equations and range estimation equations are derived and the modified range prediction method with correction factor is presented. It is verified that the proposed method can predict the residual flight range accurately. After that, the lateral pulse jets control is presented and utilized to correct the trajectory and eliminate the range error. A unique control law is reported that combines elliptic ballistic theory and control mode for lateral pulse jets. The impact point is directly controlled and rocket dispersion in the longitudinal direction is efficiently reduced.
Air Breathing Rocket Engines and Sustainable Launch Systems
Authors: Amar S. , Gowtham Manikanta Reddy T.
Published: November 2012

An air-breathing rocket engine inhales oxygen from the air for about half the flight, so it doesn't have to store the gas onboard. So at take-off, an air-breathing rocket weighs much less than a conventional rocket, which carries all of its fuel and oxygen onboard. Air breathing rockets, combine the performance characteristics of both rocket and ramjet engines. An air-breathing engine gets its initial take-off power from specially designed rockets, called air-augmented rockets, that boost performance about 15 percent over conventional rockets. When the vehicle's velocity reaches twice the speed of sound, the rockets are turned off and the engine relies totally on oxygen in the atmosphere to burn the hydrogen fuel. Once the vehicle's speed increases to about 10 times the speed of sound, the engine converts to a conventional rocket-powered system to propel the vehicle into orbit. And therefore reducing a vehicle's weight decreases cost significantly. And since an air breathing engine cannot get required initial take off thrust, various launch types like air augmented rockets, horizontal launch mode courtesy hybrid engine, magnetic levitation launch systems are used for initial thrust requirements ,thus reducing fuel emissions and increases net efficiency of rockets. Hence air breathing engines can be implemented to address energy considerations and reduce costs.
Discharge Characteristics of a Laser-Electromagnetic Coupling Plasma Thruster for Spacecraft Propulsion
Authors: Zhang Dai Xian , Zhang Rui , He Zhen , Zhang Fan , Wu Jian Jun
Published: November 2012

The main aim of this work was to construct and investigate an optical and electromagnetic coupling thruster for spacecraft propulsion. This thruster, called as laser-electromagnetic coupling plasma thruster (LEMPT), ablates solid propellants, ionizing the gaseous matter and forming a plasma jet to export impulse bit for the spacecraft. Firstly, tests were performed analyzing the influence of physical variables (initial voltage bias of capacitors, i.e., storage energy of capacitors and laser output repetition frequency) on the discharge characteristics which represents the performance of the thruster. Secondly, the stability quality of the thruster is tested and evaluated in experiment. Ethylene-vinyl acetate copolymer (known as EVA) is used as a propellant for the thruster in the experiments herein. The results have shown that this LEMPT can be used for spacecraft in the future.
Influence of Electrode Flare Angle on the Performance of Pulsed Plasma Thruster
Authors: Zhang Rui , Zhang Dai Xian , He Zhen , Zhang Fan , Wu Jian Jun
Published: November 2012

In order to study the influence of electrode flare angle on the performance of Ablation Pulsed Plasma Thruster. Discharge character, plasma velocity and performance over different electrode flare angles of the Pulsed Plasma Thruster at 13.5J initial energy are measured experimentally, the effect of electrode flare angle on the electrode inductance gradient, equivalent circuit parameters and energy transfer efficiency are analyzed. It can be seen that the circuit parameters and inductance distribution are changed with electrode flare angle, the impulse bit, specific impulse, thruster efficiency and mean exhaust velocity increase non-linearly with flare angle increasing from 0 degree to 27 degree and the Pulsed Plasma Thruster gets the maximum thruster performance at 27 degree flare angle. It shows that with the increase of electrode flare angle the fraction of ablated mass accelerated magnetically and the impulse bit created by Lorentz force decrease are the reasons inducing the change in thruster performance.
Autonomous Laser Guided Vehicle for Book Deposition in a Library
Authors: Mehta Nimish , Limaye Pushkar , Talnikar Chaitanya , Joshi Prathamesh
Published: November 2012

This paper proposes a technology to automate the book deposition process in a generic Library layout. It includes usage of autonomous vehicle in the library that is guided by an assembly of lasers. To prove the practicability of this proposal a physical prototype of an autonomous robot has been developed. The robot acts as an external storage unit for books and is capable of delivering them from the initial pre-defined point to the desired final destination.
The Microstructure and Hardness of Al2O3 Particle Reinforced Composite
Authors: Şahin Y. , Öksüz K. Emre
Published: November 2012

Aluminium alloys (Al2014 and Al2124 alloy) and their composites containing 10wt.% Al2O3 with 3 µm and 43 µm sizes of particles have been produced by powder metallurgy (PM) method and the microstructure and hardness were investigated. Scanning electron microscopy (SEM) investigation showed a nearly uniform distribution of the Al2O3 particles within the Al2124 alloy matrix although some porosities were found in the Al2014 alloy matrix. Furthermore, it was found that the macrohardness of Al2124 alloy composite improved highly in comparison to that of Al2014 alloy due to fine of microstructure and increased hardness. The hardnesses of both MMCs increased with increasing the particle sizes.
CBR Based Collision Avoidance Approach to Reactive Control for Multi-Robot System
Authors: Liu Qiang , Ma Jia Chen , Zhang Qi
Published: November 2012

In this paper we discuss a Case-Based Reasoning (CBR) method which is an on-line learning mechanism for dynamic selection and modification of behavior assemblages for collision avoidance of multi-robot system. The CBR module is designed as an additional reactive control system which provide flexible performance in novel environments without extensive high-level reasoning that would slow the system down. The results by robot simulation software MissionLab show that the CBR are effective for making decisions to avoid the collision with static obstacles as well as moving robots in multi-robot system.
Performance Optimisation of Mobile Robots for Search-and-Rescue
Authors: Choi S.H. , Zhu W.K.
Published: November 2012

This paper presents a team performance optimisation system for multiple mobile robots in search-and-rescue operations, in which refugees are first discovered and subsequently robots are dispatched to transport themto shelters. Coordination of mobile robots involves two fundamental issues, namely task allocation and motion planning. While task allocation assigns jobs to robots, motion planning generates routes for robots to execute the assigned jobs. Task allocation and motion planning together play a pivotal role in optimisation of the robot team performance. These two issues become more challenging in dynamic search-and-rescue environments, where the refugees are unpredictably discovered at different locations and the traffic conditions of rescue zones keep changing. Weaddress these two issues by proposing an auction-based closed-loop module for task allocation and a bio-inspired intelligent module for motion planning. The task allocation module is characterised with a closed-loop bid adjustment mechanism to improve the bid accuracy even in light of stochastic rescue requests. The motion planning module is bio-inspired intelligent in that it features detection of imminent neighbours and responsiveness of virtual force navigation in dynamic traffic conditions. Simulations show that the proposed system is a practical tool to optimise the dynamic operations of search-and-rescue by a team of mobilerobots.
Improved Hough Transform Applying in Mobile Robot Vision Navigation
Authors: Jiang Yin Ping , Zhang Xian Xian , Fu Xiao Peng
Published: November 2012

This paper mainly discusses that in mobile robot vision navigation system, by using the improved Hough transform, we can improve the accuracy of line extraction and therefore avoid the image quality reduction caused by noise points. Considering the limitations of the standard Hough transform, we come up with a method with which we will accumulates the H (ρ, θ) through distributing the increment value, set a global threshold to shun the pointless measurements, eliminate the false lines by comparing θ difference between tow arbitrary lines, find the peaks by using rectangle window, and set a local threshold to eliminate false peaks. In this way, we can gain a method superior to the standard Hough transform which works better in extracting lines in application. The experiments show that this method can not only extract line features of geometric figure effectively in brief background, but also eliminate the iterative lines efficiently.
A Method for Solving Dynamic Equations of a 3-PRR Parallel Robot
Authors: Nabavi S. Nader , Akbarzadeh Alireza , Abolghasemi Saeed
Published: November 2012

In this paper, kinematic relationships for a 3-PRR planar parallel robot are first presented. The robot dynamics equations are formulated using Lagrange equations of first kind. The derived equations are a mixed set of differential and algebraic constraint equations, DAE, which must be satisfied simultaneously. In order to solve the robot dynamic equations, a new method is presented in which the dynamics equation is first partitioned into two parts. The constraint equations and the dependent coordinates are next eliminated. This reduces the dynamic equations to a set of differential equations as a function of three independent coordinates. Finally, a trajectory for the robot end-effector is specified and PD controller which follows the desired trajectory is implemented. The proposed method significantly simplifies the solution of the dynamics equations.
Robustness Compensation Control of Simulation Loading System Based on Secondary Regulation
Authors: Wang Jie , Wang Hui , Xu Zhuo
Published: November 2012

This study investigated a mathematical model which was built for a simulation loading system based on secondary regulation. Because the loading system was complicated in structure and some other factors, the control performance was not ideal. Therefore, a dynamic robust compensating controller was designed for the system. The robust compensator could improve the control system by adding the return-to-zero factor and low pass filter on the basis of PID control. This study used MATLAB to simulate the general PID control and the robust compensation control. The results of simulation showed that when the equivalent rotary inertia and damping coefficient changed, the control performance decreased. When using the dynamic robust compensation control, the influences caused by parameter variations were reduced greatly, the system robustness and control accuracy are improved.
Micro-Vibration Analysis and Measurement on High Resolution Remote Sensing Satellites
Authors: Miao Hui , Song Guang Lei , Liu Qiang
Published: November 2012

Because micro-vibration environment of the high resolution remote sensing satellite makes great influence on image quality, it is necessary to design micro-vibration measurement equipment to accurately measure the micro-vibration parameters which impact the CCD imaging quality. The paper proposes a set of template to design the parameters of the micro-vibration on board. Starting from the change of CCD modulation transfer function (MTF) due to the micro-vibration, we can build the model, analyze the relationship of the CCD MTF and the frequency and the amplitude, and then we can determine the minimum of the angular displacement and the angular velocity. Finally design and conclude a set of logical, realizable and optimal template, which can afford facilities for the design on the parameters of measuring micro-vibration on the other high resolution remote sensing satellites.
Vibrations of a Non Jeffcott Rotor with One Non Linear Bearing
Authors: Vardhan Akash
Published: November 2012

Magnetic bearings support a body by mechanical pulling forces without any mechanical contact. They consist of an electromagnetic actuator, position sensors, power amplifiers and feedback controller. All of these components are characterized by nonlinear behavior and hence the entire system is inherently nonlinear. This paper presents a mathematical model for the vibrations of a non-Jeffcott type rotor supported on a non-linear bearing. The model can be used as a reference for systems supported on nonlinear bearings like magnetic bearings.
Dynamics of Cantilever Beams due to Time-Dependent Excitations and their Suppression
Authors: Rebei Adnan , Al-Saif Khalid
Published: November 2012

A Fourier Transform method is applied to determine the displacements of a cantilever beam subjected to a multi-frequency excitations at the base. To dampen the displacements of the beam, a point mass is attached to the beam. The position of the mass on the beam is determined such that the overall deflections of the beam are minimal. It is shown that these attachments to the beam are effective in reducing the vibrations of the beam but their position is frequency dependent. It is shown that the low frequency component of the external excitation is most important in finding the optimal position of the mass.
Direct Computational Method for Life Prediction of UD Fibre Reinforced Polymers Based-on Plasticity-Damage Simulation
Authors: Vasiukov Dmytro , Panier Stephane , Hachemi Abdelkader
Published: November 2012

New direct method was developed for fibre reinforced polymers subjected to fatigue loading. Constitutive model is based-on coupled plasticity-damage framework. Microstructure of material is satisfying the periodic conditions. Influence of microstructure has been involved through stress concentration tensor. Plasticity yield surface is described by modified Raghava criterion. Damage of matrix and transverse cracking are governed by quadratic damage surface. Method was examined on the standard example of unidirectional composite plate with carbon-fibre reinforced. Significant reduction of calculation time has been achieved using the direct computational algorithm.
Dynamic Simulation on Shock Excitation Hydraulic System with Rotary Valve Based on AMEsim
Authors: Wang Hui , Deng Zong Yue
Published: November 2012

Introduce structure and working principle of shock excitation hydraulic system in VSR equipments, establish its simulation model with advanced modeling software .Through dynamic simulation get simulation curves under different conditions, and analyses some important parameters’ influents on the system, and provide the basis for testing and improving the system.
Helicopter Maneuver Flight Simulation and Control Law Design
Authors: Wang Jing Ying
Published: November 2012

This paper presents a solution to helicopter maneuver flight simulation according to ADS33 flying qualities requirement standard. Associated with aerodynamics and control law design methodology, the proposed scheme achieved satisfactory control performance by analyzing helicopter attitude and control parameter variation law at certain operating condition. To level flight acceleration, method based on force and moment balance is analyzed. To pirouette maneuver, a segment linear approximated trajectory is developed for attitude and velocity stability. All objective function is based on minimizing position error and attitude error. For a single rotor four bladed model helicopter in pirouette maneuver, experimental results certified its efficiency.
An APIm Algorithm to Solve the Scheduling Problem in an FMS with Presence of Breakdowns
Authors: Yamina Houbad , Mehdi Souier , Ahmed Hassam , Zaki Sari , Fayçal Belkaid
Published: November 2012

Ant colony algorithms are computational methods inspired from the behavior of real ant colonies. In this paper our interest is focused on the adaptation of an optimization algorithm called API based on the foraging behavior model of primitive ants’ population called Pachycondyla apicalis to solve real time alternative routings selection problem in a Flexible Manufacturing System (FMS) with and without presence of breakdowns. The FMS consists of seven machining centers, a loading and an unloading stations, and six different part types. Owing to the presence of identical machining centers, the parts have alternative routings. The scheduling decisions has been established in terms of how the parts are routed through various machines in the system.
Modeling of Layering Ceramic Shell Mould
Authors: Harun Zawati , Nawi Nazri Mohd , Batcha Mohd Faizal , Gethin David
Published: November 2012

This paper presents the modeling the drying process of shell mould layering process for the ceramic shell mould fabrication process. As this process involves the repeated drying of the different wetted/saturated layers, therefore modeling of this phenomena involve a sequent approach to tackle the whole development of shell mould layering process. In this work an Ab-Initia approach was selected as the best simulation technique to map the drying mechanism. Saturation or moisture content was selected as the best parameter that will represent the drying of layering process. Using FEM with quadrilateral shape mapping of several interested points were selected to predict the moisture/saturation movement during the drying of shell layering stages. Standard drying time with 2 hours and early drying time were chosen to measure the moisture movement as layer added to the previous dried coated shell or layers. This complex mechanism of drying and penetration layering shell were then numerically solve with fully implicit backward time stepping scheme. Hopefully, this model and can be used to measure the complex movement of the main parameter i.e saturation/temperature in the drying process of multilayer system which is sometimes impossible directly measured under experimental technique
Modeling Approach of a Near-Space Airship Using Newton-Euler and Lagrangian Formulation
Authors: Yang Yue Neng , Wu Jie , Zheng Wei
Published: November 2012

This paper presents dynamics modeling approach of the near-space airship. First, reference frames and motion variables of the airship are defined, and dynamics model of an airship is derived from the Newton-Euler formulation. Second, the Lagrangian modeling approach in terms of quasi-coordinates is presented, and dynamics model is derived form the Lagrangian formulation, considering the airship and its ambient air as a “rigid body-fluid” system from an energy point of view. The added inertial, gravity, aerostatics, and dissipative forces are incorporated into the dynamics model, and are expressed as parameterized matrices in a common framework. Third, the validity of the proposed dynamics model is verified by comparing simulations with the dynamics model derived from Newton-Euler formulation.
Modeling of Planar Embedded Cracks of Arbitrary Shape under Non Uniform Mode I Loadings
Authors: Hachi Brahim Elkhalil , Guesmi Mohamed , Haboussi Mohamed
Published: November 2012

A numerical method using the weight function technique is proposed in order to evaluate the stress intensity factors for planar cracks of an arbitrary shape under non uniform mode I loadings. In accordance with the crack front perturbation theory of Rice, the SIFs are calculated in an incremental way, from a known initial crack shape (circle) which we make evolve until the final form is reached. Due to the non uniform character of the loading a surface integral term reappears during the calculation of the SIF which disappeared in the uniform case. This surface integral contribution to the calculation of the SIF depends on a kernel function which we propose to approximate by an empirical weight function that was developed by Oore and Burns (OB) for embedded cracks of any shape. The OB weight function introduces new singularities in the SIF evaluation that we propose to treat numerically. Several tests of validation are proposed to appreciate the predictive capacity of the proposed model.
Dynamic Fault Trees Analysis for Importance Measures Based on Cut Sequence Set Model
Authors: Liu Dong , Chen Xiao Juan , Li Yi , Zhao Zhong Wen , Li Xin Ming
Published: November 2012

Importance Measures (IMs) for dynamic fault tree (DFT) remains widely open, for that Markov-based methodology is limited to exponential distributions as well as the state space explosion. Cut sequence describes the dynamic behaviors among components, and Cut sequence set (CSS) model provides ways to generate and calculate the probabilities of cut sequences, but it does not show how to analysis IMs using CSS model. This paper proposed a novel methodology of IMs in CSS model, including Birnbaum measure (BI), Risk Achievement Worth (RAW) and Structure Importance (SI) and an example demonstrates the superiority of the methodology. In contrast to the Markov-based methodology, the proposed methodology is combinatorial and can handle with any type of time-to-failure distributions for the system components.
Modeling of Urea-Water Solution Injection Spray in SCR System
Authors: Nagaraj Nayak S. , Kapilan N. , Sadashiva Prabhu S.
Published: November 2012

To control the emissions from the diesel engines of modern automobiles, it requires the development of adequate and advanced exhaust gas aftertreatment devices. Selective Catalytic Reduction (SCR) is a method that can be used in mobile diesel engine aftertreatment systems to reduce harmful NOx emissions. Due to the toxicity and handling problems of ammonia, currently injection of a liquid Urea-Water Solution (UWS) into the exhaust stream approach is used. The water evaporates and the urea undergoes thermal decomposition producing ammonia that reacts with the NOx in the exhaust gas inside a SCR catalyst to produce nitrogen and water vapor. This work presents the study of UWS injection spray using commercial available CFD code, Fire v8.3. The evaporation of water from a single droplet of UWS is investigated theoretically and droplets are treated with Lagrangian particle tracking. Simulation study at different exhaust gas temperatures and injector locations is carried out and compared with experimental values. Thus, the present study results predict the local distribution and the conversion of the reducing agent.
Area Symbol Model for GIS Based on AutoCAD
Authors: Yang Ping , Li Guo Juan , Zhang Xiao Zhi
Published: November 2012

Area symbol is an import part for GIS area objects, and area symbol model is essential to GIS. The traditional area symbol model widely used in domestic is elaborated in detail, and abnormal status came from the defective model are analyzed. In order to solve the questions, the common ground between AutoCAD hatch model and the existing GIS area model is pursued. And on this basis, an area symbol model for GIS based on array structure is proposed, that could avoid the basic problem of area display by area symbol. Accordingly, some suggestions are put forward for the change of area symbol model.
Influence of Optimization Algorithm on Airfoil Shape Optimization of Aircraft Wings
Authors: Mukesh R. , Lingadurai K. , Elamvaluthi K.
Published: November 2012

Computational fluid dynamics (CFD) is one of the computer-based solution methods which are more widely employed in aerospace engineering. The computational power and time required to carry out the analysis increases as the fidelity of the analysis increases. Aerodynamic shape optimization has become a vital part of aircraft design in the recent years. The Method of search algorithms or optimization algorithms is one of the most important parameters which will strongly influence the fidelity of the solution during an aerodynamic shape optimization problem. Nowadays various optimization methods such as Genetic Algorithm (GA), Particle Swarm Optimization (PSO) etc., are more widely employed to solve the aerodynamic shape optimization problems. In addition to the optimization method, the geometry parameterisation becomes an important factor to be considered during the aerodynamic shape optimization process. Generally if we want to optimize an airfoil we have to describe the airfoil and for that, we need to have at least hundred points of x and y co-ordinates. It is really difficult to optimize airfoils with this large number of co-ordinates. Nowadays many different schemes of parameter sets are used to describe general airfoil such as B-spline, Hicks- Henne Bump function, PARSEC etc. The main goal of these parameterization schemes is to reduce the number of needed parameters as few as possible while controlling the important aerodynamic features effectively. Here the work has been done on the PARSEC geometry representation method. The objective of this work is to introduce the knowledge of describing general airfoil using twelve parameters by representing its shape as a polynomial function. And also we have introduced the concept of Particle Swarm optimization Algorithm which is one kind of Non-Traditional Optimization technique to optimize the aerodynamic characteristics of a general airfoil for specific conditions. An aerodynamic shape optimization problem is formulated for NACA 2411 airfoil and solved using the method of Particle Swarm Optimization for 5.0 deg angle of attack. A MATLAB program has been developed to implement PARSEC, Panel Technique, and PSO Algorithm. This program has been tested for a standard NACA 2411 airfoil and optimized to improve its coefficient of lift. Pressure distribution and co-efficient of lift for airfoil geometries has been calculated using panel method. NACA 2411 airfoil has been generated using PARSEC and optimized for 5.0 deg angle of attack using PSO Algorithm. The results show that the particle swarm optimization scheme is more effective in finding the optimum solution among the various possible solutions.
On the Optimization of Vent Arrangement in a Subway Station
Authors: Sojoudi Atta , Vakilimoghaddam Farbod , Neishapouri Reihaneh
Published: November 2012

Toxic gases resulted from fire events in subways stations are more dangerous than high temperature radiation from it. So, a well designed smoke exhaust system must be installed in subway station to control the smoke’s propagation and discharging. Smoke extraction in subway station depends on the duct laid above the ceiling, so vents are situated in the same level of platform layer’s ceiling. If subway station catches fire, smoke will cumulate in smoke reservoirs at the beginning and mechanical fan cannot exhaust any smoke in this process. In This paper, FDS 5.0 is used to simulate smoke’s movement in a side platform of an actual subway station in case of a fire. Simulations are carried out at the same volume flux of mechanical fan to investigate the effects of height of vents and depth of smoke reservoirs.
3-D Path Planning for UAV Based on Chaos Particle Swarm Optimization
Authors: Cheng Ze , Tang Yi Xin , Liu Yan Li
Published: November 2012

An improved chaos particle swarm optimization (CPSO) algorithm is proposed on path planning for unmanned aerial vehicle (UAV) to overcome the inadequacy of particle swarm optimization (PSO) algorithm, which falls into local optimum easily and converges slowly in process with poor precision. Through the in-depth analysis of PSO algorithm, the chaos optimization (CO) algorithm principle is introduced into it based on the traditional update operations on the particles’ velocity and position; as a result, the diversity of particles is increased, the suboptimal search on path planning is avoided and the quickness accompanied with accuracy of convergence is improved. Combined with digital map for modeling the UAV’s flight environment, the 3-D path planning is achieved. As the simulation results demonstrated, this hybrid algorithm is superior to the traditional PSO algorithm on path searching, especially in the 3-D environment.
The Design and Optimization of Fuzzy Controller Based on Vibrating Mill Granularity
Authors: Zhang Jin Hua
Published: November 2012

Granularity is the main parameter of evaluating materials, from the analysis of powder producing system that made of vibration mill, the material’s size can be controlled through controlling the speed of motor. Focus on the complex nonlinear in the processing of ground breaking, the two dimensional controller is designed. Due to the subjectivity and randomness in the designing method of classic fuzzy controller, so genetic algorithm is used to put fuzzy controller some learning function in order to obtain better control effect of the system.
A Comprehensive Approach for Thermal Error Model Optimization for ANN-Based Real-Time Error Compensation in CNC Machine Tools
Authors: El Ouafi Abderrazak , Guillot Michel
Published: November 2012

Thermally induced errors play a critical role in the control of machining accuracy. They can account for as much as 70% of dimensional errors in produced parts. Since thermal errors cannot totally be eliminated at the design phase, errors compensation appears to be the most economical solution. Accurate and efficient modeling of the thermally induced errors is an essential part of the error compensation process. This paper presents a comprehensive approach for thermal error modeling optimization. The proposed optimization method is based on multiple temperature measurements, Taguchi’s orthogonal arrays, various statistical tools and artificial neural networks to provide cost effective selection of appropriate temperature variables and modeling conditions as well as to achieve robust and accurate thermal error models. The proposed approach can be effectively and advantageously used for real-time thermal error compensation since it presents the benefit of straightforward application, reduced modeling time and uncertainty. The experimental results on a CNC turning center confirm the feasibility and efficiency of the proposed optimization method and show that the resultant model can accurately predict the time-variant thermal error components under various operating conditions.
Optimal Trajectory of Flexible Manipulators Using Genetic Algorithms
Authors: Ata Atef A. , Haraz Eman H. , Rizk A. Elfattah A. , Hanna Sarwat N.
Published: November 2012

The applications of flexible manipulators are increasing and due to the high demand on fuel consumption there is a need to optimize the energy consumption for stable and durable operation of the flexible manipulators. In the present work the Genetic Algorithm (GA) is employed to optimize the total torque and the torque of the first link of a two-link flexible manipulator with a fourth order polynomial trajectory. The mathematical model of the manipulator is obtained using the extended Hamilton's Principle where the flexible links are treated as Euler- Bernoulli's beam theory. A fifth order polynomial trajectory undergoes a rest-to rest maneuvering is proposed as a bench mark for validation.
Optimize the Satellite Orientation by Using the Inertial Pulse Method, Intelligent Damper, Dynamics, Kinematics and Proper Neural Network
Authors: Olaru Adrian
Published: November 2012

In the paper are shown one assisted method of the control orientation inertial mechanism of the small satellite. It is presented some of the general components of the small satellite and the possibility to orientation them between three axes using the inertial pulse of the electrical motors. The angular space position was determines by command of the final point and using the proper neural network to solve the inverse kinematics problem with the minimum of the errors. The precision of the space orientation position was increased by using in the proper controlling schema a direct kinematics module, direct and inverse dynamics, intelligent damper and one multiple inertial pulse method what was described in the paper. Finally was obtained one very good precision, before 2%.The neural network, the inertial pulse method, the results and the virtual LabVIEW instrumentation could be used in many other researches on the field.
Global Stability Properties for Neutral-Type Hopfield Neural Networks
Authors: Hao Dao He , Wu Liang
Published: November 2012

The global stability properties was discussed for the neutral-type Hopfield neural networks with discrete and distributed time-varying delays .Based on the Lyapunov functional stability analysis and the linear matrix inequality approach, a new sufficient condition was derived to assure the global stability properties of the equilibrium. The criterion improved and extended the results of literature, and has less conservative.
Research on Authentication-Based Security Technology for Complex Networks
Authors: Li Yi , Liu Dong , Wang Bo , Li Xin Ming
Published: November 2012

The concept of authentication network is proposed to solve the security problems of complex network. The basic idea of authentication network is to ensure that everything of network must be authenticated. The technologies about authentication node, including the trusted root and trusted chain are studied. The security technologies about authentication networks, including trusted transmission, distributed and tree authentication management, multistage and multilayer access control strategy are also researched. At last, the security abilities of authentication network are analyzed.
Integrated Thermal Management System Design for Advanced Propulsion System
Authors: Lou De Cang , Guo Wen , Wang Zhi Guo , Wang Yong Hong
Published: November 2012

Thermal management system (TMS) design is considered to be a key technology for advanced aero engines and supersonic or hypersonic propulsion systems. In this paper, the concepts of coupling flow and thermodynamic networks are proposed for TMS design. In this method, the propulsion system is considered to be a zero-dimensional flow system. Components, subsystems and hence the entire engine system can be modelled using some basic flow and thermodynamics networks. The platform for TMS design, ThermalM, is developed based on this model. As an example, modelling for a Turbine Based Combined Cycle (TBCC) thermal management system is described. Performance of the fuel heat exchanger in the network is discussed in detail. With the TMS design technology, performance of the advanced propulsion system can be analysed.
Numerical Simulation of Phase Change Thermal Storage in Finned Double-Pipe Heat Exchanger
Authors: Shokouhmand H. , Kamkari B.
Published: November 2012

This paper presents numerical investigations on melting of phase change material using paraffin wax inside a double pipe heat exchanger. Numerical simulations are performed for melting of phase change material (PCM) in annulus while the inner pipe has two or four longitudinal fins and the results compared with inner bare tube. The aim of this study is to understand the PCM melting behaviors by observing the natural convection currents movement and melting fronts formation. It is concluded that melting performance of PCM can be significantly improved by applying longitudinal fins on the inner tube.
A Numerical Study on Heat Transfer and Lubricant Depletion on an Anisotropic Multilayer Hard Disk
Authors: Zeng Yan , Huang Xiao Yang , Zhou Wei Dong , Yu Sheng Kai
Published: November 2012

This paper presents a numerical investigation on the effect of thermal anisotropy of the top layer alloy on heat transfer and lubricant depletion on the disk surface in a heat-assisted magnetic recording (HAMR) system. The disk consists of multilayer structures and a thin layer of lubricant on the top surface. Cases under different laser powers and initial lubricant film thicknesses are examined. The top-layer alloy thermal anisotropy does show non-negligible effect on the heat transfer and lubricant depletion. With the top-layer alloy being more anisotropic, higher temperature increase and lager lubricant depletion can be observed on the disk surface. The results also show that the thermal anisotropy effect is more significant under a lower laser power but nearly keeps no much difference under different initial lubricant film thicknesses. Thus it is of importance to include the thermal anisotropy effect of the top-layer Co-alloy when simulating the heat transfer and lubricant depletion in practical multilayer HMAR systems, especially for the cases under the condition of lower laser power, as the effect cannot be neglected under such conditions.
Multiple Nonlinear Regression Analysis for the Prediction of Macroscopic Elastic Properties on Composite Containing Interphase
Authors: Liu Yu Jia , Yan Ying , She Hai Qiang
Published: November 2012

A convenient method to predict the macroscopic elastic performance of composite containing interphase was proposed in this paper. Firstly, a 3-D three-phase micromechanical model with randomly distributed fibers was established with the Moving Window Method (MWM), and the macroscopic elastic properties of T300/914C were predicted using energy method. Secondly, the multiple nonlinear regression correlation between the macroscopic elastic properties and micromechanical characteristic parameters of the interphase was established based on numerical data. Finally, the macroscopic elastic properties of T300/914C containing interphase were predicted using the regression model. Results indicate that the relative error for the longitudinal modulus is within ±1% while it is within ±3.5% for the transverse modulus, and shear modulus.
Augmentation of Convective Heat Transfer of Highly Viscous Fluid within Three-Dimensional Internally Finned Tube
Authors: Zhang Chuan , Gao Sheng Jian , Song Xiao Yong , Chen Fei , Liao Guang Ya
Published: November 2012

Investigation on the heat transfer and friction characters for fresh oil flowing inside three-dimensional internally finned tube (3-DIFT) was carried out with orthogonal experimental design method. Reynolds numbers varied from 30 to 800，Prandtl numbers 550 to 1000. The experimental results showed that low critical Reynolds numbers at the range of 100 to 200 were attained within all the experimental tubes, which indicated that 3-DIFT could obvious accelerate the transformation of high viscous fluid from laminar flow to turbulent flow. It offered a particular advantage to enhance the convective heat transfer of highly viscous fluid. Empirical equations on flow resistance and heat transfer were obtained using a least-squares regression. Compared with empty smooth tube, the maximal thermal performance factor for the turbulent flow within 3-DIFT could be enhanced up to 3.61. The optimization on shape of 3-DIFT for further augmentation heat transfer was also obtained.
The Features of Microwave Thermal Conversion of Oil Sludge
Authors: Wang Wan Fu , Li Guo , Yong Xing Yue , Liu Peng , Zhang Xiao Fei
Published: November 2012

The microwave thermal conversion process of oil sludge was studied. It was found that the microwave thermal conversion process of oil sludge consisted of 5 stages: rapid heating, microwave drying, microwave hydrocarbons evaporation, microwave pyrolysis and microwave calcining. Using the residue produced from the microwave thermal treatment of oil sludge as a microwave absorbent can significantly accelerate the conversion. However, it does not show significant effect on the features of microwave thermal conversion. Meanwhile, the addition of residue at appropriate percentages increased oil recovery rate. The non-condensable gases consist of H2 and C1~C5 hydrocarbons. The recovered oil was mainly produced at microwave evaporation and microwave pyrolysis stages, consisting of 89% light oil and 11% heavy oil.
A Micro Gas Turbine Fuelled by Methane-Hydrogen Blends
Authors: Reale Fabrizio , Calabria Raffaela , Chiariello Fabio , Pagliara Rocco , Massoli Patrizio
Published: November 2012

The combustion efficiency and the gaseous emission of a 100 kWe MGT, designed for working with natural gas but fuelled with blends containing up to 10% of hydrogen is investigated. A critical comparison between experimental data and results of the CFD analysis of the combustor is discussed. The k-epsilon RANS turbulence model and the Finite Rate – Eddy Dissipation combustion model were used in the numerical computations. The chemical kinetic mechanisms embedded were the 2-step Westbrook and Dryer for methane oxidation, 1-step Westbrook and Dryer for hydrogen oxidation and the Zeldovich mechanism for NO formation. The experimental data and numerical computations are in agreement within the experimental accuracy for NO emissions. Regarding CO, there is a significant deviation between experimental and computational data due to the scarce predictive capability of the simple two steps kinetic mechanism was adopted. From a practical point of view, the possibility of using fuels with a similar Wobbe index was confirmed. In particular the addiction of 10 % of hydrogen to pure methane doesn’t affect the behavior of the micro gas turbine either in terms of NO or CO emissions.