Advances in Mechanical Engineering http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Influence of Splitter Blades on the Cavitation Performance of a Double Suction Centrifugal Pump Thu, 17 Apr 2014 17:18:55 +0000 http://www.hindawi.com/journals/ame/2014/963197/ In order to study the influence of splitter blades on double suction centrifugal pumps two impellers with and without splitter blades were investigated numerically and experimentally. Three-dimensional turbulence simulations with and without full cavitation model were applied to simulate the flow in the two pumps with different impellers. The simulation results agreed with the experiment results and the internal flows were analyzed. Both the numerical and experimental results show that by adding splitter blades the hydraulic performance and the cavitation performance of the pump are improved. The pump efficiency is increased especially at high flow rate condition. The pump high efficiency area is extended dramatically. At the same time since the splitter blades share some part of the blade loading, the pump critical NPSH value is decreased. Obvious pressure increase and velocity decrease at blade suction surface near leading edge were observed in the pump impeller with splitter blades. And the pump cavitation performance was improved consequently. Wei Yang, Ruofu Xiao, Fujun Wang, and Yulin Wu Copyright © 2014 Wei Yang et al. All rights reserved. An Investigation on the Effect of Axial Pressures on the Mechanical Properties of Friction Welded Dissimilar Steels Thu, 17 Apr 2014 14:02:05 +0000 http://www.hindawi.com/journals/ame/2014/639378/ The aim of the present study was to investigate the effect of axial pressures on the mechanical properties of friction welded AISI 304 with AISI 1021 steels, produced by mechanical joining. In the present study, an experimental setup was designed in order to accomplish friction welded joints between austenitic stainless steel and low alloy steel. Samples were welded under different axial pressures, at a constant speed of 800 rpm. The tensile strength, impact strength, and microhardness values of the welded joints were determined and evaluated and on the basis of the results obtained from the experimentation, the graphs were plotted. Amit Handa and Vikas Chawla Copyright © 2014 Amit Handa and Vikas Chawla. All rights reserved. Viscoelastic Parameter Model of Magnetorheological Elastomers Based on Abel Dashpot Thu, 17 Apr 2014 13:40:49 +0000 http://www.hindawi.com/journals/ame/2014/629386/ In this paper, a parametric constitutive model based on Abel dashpot is established in a simple form and with clear physical meaning to deduce the expression of dynamic mechanical modulus of MREs. Meanwhile, in consideration for the pressure stress on MREs in the experiment of shear mechanical properties or the application to vibration damper, some improvements are made on the particle chain model based on the coupled field. In addition, in order to verify the accuracy of the overall model, five groups of MREs samples based on silicone rubber with different volume fractions are prepared and the MCR51 rheometer is used to conduct the experiment of dynamic mechanical properties based on frequency and magnetic field scanning. Finally, experimental results indicate that the established model fits well with laboratory data; namely, the relationship between the dynamic modulus of MREs and changes in frequency and magnetic field is well described by the model. Fei Guo, Cheng-bin Du, and Run-pu Li Copyright © 2014 Fei Guo et al. All rights reserved. Energy Harvesting Shock Absorber with Electromagnetic and Fluid Damping Thu, 17 Apr 2014 13:12:43 +0000 http://www.hindawi.com/journals/ame/2014/693592/ During the last two decades, attempts have been made by researchers to build integrated suspension/generation unit that can replace conventional fluid shock absorbers in vehicles. However, heavier weight is limiting commercial application of the present systems. This paper presents design and analysis of an efficient energy harvesting hydraulic electromagnetic shock absorber with least weight penalty on the vehicle. The conceived shock absorber uses mechanical amplification and linear generator along with displacement sensitive fluid damper. Prototype linear generator operating with velocity amplification improves harvested voltage to 660%. Full scale model of the presented system will harvest peak energy of 176–227 J for suspension velocities of 0.25–0.40 m/sec. Finite element analysis in ANSYS is used to derive optimum generator dimensions. Numerical model of the present system with fluid and electromagnetic damping has been constructed in Matlab Simscape. Inductive voltage drop and harvesting threshold voltage are found to contribute nonlinearity of the electromagnetic damping force. Quarter car model constructed in Matlab is used to evaluate motion transmissibility, acceleration transmissibility, and wheel motion. Satisfactory performance of the system is confidently validated with experimentations performed on a scaled-down prototype. Nitin V. Satpute, Shankar Singh, and S. M. Sawant Copyright © 2014 Nitin V. Satpute et al. All rights reserved. A Modified Method for Calculating Notch-Root Stresses and Strains under Multiaxial Loading Thu, 17 Apr 2014 13:08:07 +0000 http://www.hindawi.com/journals/ame/2014/513804/ Based on the analysis of notch-root stresses and strains in bodies subjected to multiaxial loading, a quantitative relationship between Neuber rule and the equivalent strain energy density method is found. In the case of elastic range, both Neuber rule and the equivalent strain energy density method get the same estimation of the local stresses and strains. Whereas in the case of elastic-plastic range, Neuber rule generally overestimates the notch-root stresses and strains and the equivalent strain energy density method tends to underestimate the notch-root stresses and strains. A modified method is presented considering the material constants of elastic-plastic Poisson's ratio, elastic modulus, shear elastic modulus, and yield stress. The essence of the modified model is to add a modified coefficient to Neuber rule, which makes the calculated results tend to be more precise and reveals its energy meaning. This approach considers the elastic-plastic properties of the material itself and avoids the blindness of selecting coefficient values. Finally the calculation results using the modified model are validated with the experimental data. Liu Jianhui, Wang Shengnan, Jin Wuyin, and Gao Wen Copyright © 2014 Liu Jianhui et al. All rights reserved. Numerical Study on Flow and Heat Transfer Performance of Rectangular Heat Sink with Compound Heat Transfer Enhancement Structures Thu, 17 Apr 2014 12:35:52 +0000 http://www.hindawi.com/journals/ame/2014/457650/ Modern gas turbine blade is operating at high temperature which requires abundant cooling. Considering both heat transfer rate and pumping power for internal passages, developing efficient cooling passages is of great importance. Ribbed channel has been proved as effective heat transfer enhancement technology for considerable heat transfer characteristics; however, the pressure loss is impressive. Dimple and protrusion are frequently considered as new heat transfer augmentation tools for their low friction loss in recent years. Numerical simulations are adopted to investigate the thermal performance of rectangular channel with compound heat transfer enhancement structures with ribs, dimples, and protrusions. Among all configurations, the nondimensional dimple/protrusion depths are 0.2. The results present the flow structures of all channel configurations. The distributions of channel section are discussed for each case. The pressure penalty and the thermal performance TP are also considered as important parameters for heat transfer enhancement. It can be concluded that the optimal structure of the compound heat transfer enhancement structure is rib + protrusion ( mm) + dimple ( mm). Di Zhang, Shuai Guo, Zhongyang Shen, and Yonghui Xie Copyright © 2014 Di Zhang et al. All rights reserved. Investigation into Transient Flow in a Centrifugal Pump with Wear Ring Clearance Variation Thu, 17 Apr 2014 10:07:10 +0000 http://www.hindawi.com/journals/ame/2014/693097/ The leakage flow paths in the sidewall gaps of centrifugal pumps are of significant importance for numbers of effects. The paper is concerned with the transient flow in the leakage flow paths with wear ring clearance variation. For this purpose, numerical simulations of the whole pump were carried out. The grid dependence and yplus check were performed first. Additionally, experimental data of performance characteristic and pressure fluctuation inside the sidewall gap was used to validate the numerical results. The transient velocity fields inside the sidewall gaps during one blade passage period were simulated. And the leakage through the wear ring gap was obtained for all operating points investigated. To have a better idea of attenuation and propagation of pressure inside the sidewall gap, the unsteady pressure distributions in the gap were calculated. Additionally, the surfaces of the impeller were divided into four parts. The fluid force on each part was expressed as a percentage of the total radial force. Through comparing the flow fields, the pressure distributions, and the radial force between the pumps with different wear ring clearances, the effects of the wear ring clearance were discussed in detail. The results can be used to guide the optimum design of the pump sidewall gaps. Houlin Liu, Jian Ding, Hanwei Dai, and Minggao Tan Copyright © 2014 Houlin Liu et al. All rights reserved. Assembly Operation Optimization Based on Social Radiation Algorithm for Autobody Thu, 17 Apr 2014 08:37:04 +0000 http://www.hindawi.com/journals/ame/2014/854637/ Assembly dimensional quality affects wind noise and driving steady and whole external appearance. The quality can be improved by reducing part tolerance and fixture tolerance and optimizing key control characteristics (KCCs). However, reducing tolerance should largely increase manufacturing costs, and then the paper assembly tolerance is decreased by selecting optimal KCCs. In this work, a fitness function is presented to evaluate assembly operations based on the linear assembly variation analysis model. Afterwards, a new social radiation algorithm (SRA) is proposed to optimize KCCs, and some test functions are used to evaluate optimum performance between the genetic algorithm (GA) and SRA, and the results show that the performance of SRA is better than that of GA. Finally two cases are used to illustrate process of assembly operation optimization by SRA, and the results show that the SRA has higher precision and efficiency than that of GA. Yanfeng Xing and Yansong Wang Copyright © 2014 Yanfeng Xing and Yansong Wang. All rights reserved. A Design Outline for Floating Point Absorber Wave Energy Converters Thu, 17 Apr 2014 07:49:22 +0000 http://www.hindawi.com/journals/ame/2014/846097/ An overview of the most important development stages of floating point absorber wave energy converters is presented. At a given location, the wave energy resource has to be first assessed for varying seasons. The mechanisms used to convert wave energy to usable energy vary for different wave energy conversion systems. The power output of the generator will have variations due to varying incident waves. The wave structure-interaction leads to modifications in the incident waves; thus, the power output is also affected. The device has to be stable enough to prevent itself from capsizing. The point absorber will give optimum performance when the incident wave frequencies correspond to the natural frequency of the device. The methods for calculating natural frequencies for pitching and heaving systems are presented. Mooring systems maintain the point absorber at the desired location. Various mooring configurations as well as the most commonly used materials for mooring lines are discussed. An overview of scaled modelling is also presented. Mohammed Faizal, M. Rafiuddin Ahmed, and Young-Ho Lee Copyright © 2014 Mohammed Faizal et al. All rights reserved. Numerical Simulation of 3D Solid-Liquid Turbulent Flow in a Low Specific Speed Centrifugal Pump: Performance Comparison of Four Geometric Models Wed, 16 Apr 2014 16:28:59 +0000 http://www.hindawi.com/journals/ame/2014/678271/ For numerically simulating 3D solid-liquid turbulent flow in low specific speed centrifugal pumps, there exist several problems including how to design geometrical shape of the calculation model to represent the real pump and how to predict pump performance accurately to guide the design of pump. To solve these problems, four kinds of geometric models were designed. The performance of a low specific speed solid-liquid centrifugal pump was predicted, and the results showed that the improved prediction methods are more accurate than the traditional method. Moreover, the simulation results of the entire flow field of the geometric model including balance holes and the lateral clearances of impeller in which liquid rotates with half speed of impeller are closer to the real situation. Baocheng Shi and Jinjia Wei Copyright © 2014 Baocheng Shi and Jinjia Wei. All rights reserved. Improvement of Weldment Properties by Hot Forming Quenching of Friction Stir Welded TWB Sheet Wed, 16 Apr 2014 13:36:06 +0000 http://www.hindawi.com/journals/ame/2014/257510/ The purpose of this study is to improve the mechanical properties and formability of friction stir welded tailor-welded blanks (TWBs) of Al6061 alloy with a new forming method called hot forming quenching (HFQ) in which solid-solution heat-treated aluminum sheets are formed at elevated temperature. Forming and quenching during HFQ are simultaneously performed with the forming die for the solid-solution heat-treated sheet. In this study, specimens of aluminum TWBs were prepared by friction stir welding (FSW) with a butt joint. The effectiveness of FSW joining was evaluated by observation of the macrostructure for different sheet thicknesses. In order to evaluate the formability of TWBs by HFQ, a hemisphere dome stretching test of the limit dome height achieved without specimen failure was performed with various tool temperatures. A Vickers test was also performed to measure weldment hardness as a function of position. The formability and mechanical properties of products formed by HFQ are compared with those formed by conventional forming methods, demonstrating the suitability of HFQ for sheet metal forming of friction stir welded TWBs. Dae-Hoon Ko, Jae-Hong Kim, Dae-Cheol Ko, and Byung-Min Kim Copyright © 2014 Dae-Hoon Ko et al. All rights reserved. A New Measurement Method of Relative Volume Wear Ratio Based on Discharge Debris Composition Analysis in Micro-EDM Wed, 16 Apr 2014 12:37:58 +0000 http://www.hindawi.com/journals/ame/2014/479609/ In microelectrical discharge machining (micro-EDM) milling process, due to the unavoidability of electrode wear, selection of electrode with high electrical erosion resistance and accurate electrode compensation is entitled to be conducted to ensure high precision and high quality. The RVWR is used as criterion for electrode wear characteristics and is fundamental to achieve accurate electrode compensation; however, it is hardly measured accurately with conventional methods. In this paper, firstly, the error of RVWR measured by conventional measurement method is analyzed. Thereafter, for accurately measuring RVWR, a new measurement method is proposed based on electrical debris composition analysis. The RVWR of widely used tungsten, molybdenum, and copper electrode in machining different materials is measured, respectively, and the optimum electrode is selected based on the measuring results. Finally, microgrooves on different materials are machined with tungsten electrode, and the experiment results show that the microstructures have good bottom surface profiles, which indicates that the proposed method is effective to precisely measure the RVWR and guarantee accurate electrode compensation in micro-EDM process. Wei Liu, Zhenyuan Jia, Shangbo Zou, and Xinyi Zheng Copyright © 2014 Wei Liu et al. All rights reserved. New Regression Models for Predicting Noise Exposure in the Driver’s Compartment of Malaysian Army Three-Tonne Trucks Wed, 16 Apr 2014 10:28:40 +0000 http://www.hindawi.com/journals/ame/2014/616093/ The objective of this study is to present a new method for determination of noise exposure in the driver’s compartment of Malaysian Army (MA) three-tonne trucks based on changing vehicle speed using regression models and the statistical analysis method known as Integrated Kurtosis-based Algorithm for -notch filter (I-kaz). The test was conducted on two different road conditions: tarmac and dirt roads. Noise exposure was measured using a sound level meter which is capable of recording raw sound pressure in Pa, and comparisons were made between the two types of roads. The prediction of noise exposure was done using the developed regression models and 3D graphic representations of the I-kaz coefficient . The results of the regression models show that increases when vehicle speed and noise exposure increase. For model validation, predicted and measured noise exposures were compared, and a relatively good agreement has been obtained between them. It was found that the predictions had high accuracies and low average relative errors. By using the regression models, we can easily predict noise exposure inside the truck driver’s compartment. The proposed models are efficient and can be extended to the automotive industry for noise exposure monitoring. Shamsul Akmar Ab Aziz, Mohd Zaki Nuawi, Mohd Jailani Mohd Nor, and Dian Darina Indah Daruis Copyright © 2014 Shamsul Akmar Ab Aziz et al. All rights reserved. Study on Telescope Gain Affected by a Multilevel Hybrid Mechanism in FAST Wed, 16 Apr 2014 10:11:24 +0000 http://www.hindawi.com/journals/ame/2014/841526/ This paper focuses on the telescope gain affected by a multilevel hybrid mechanism for the feed positioning in the five-hundred-meter aperture spherical radio telescope (FAST) project, which is based on the positioning accuracy analysis of the mechanism. First, error model for the whole mechanism is established and its physical meaning is clearly explained. Then two kinds of error sources are mainly considered: geometric errors and structural deformations. The positioning error over the mechanism’s workspace is described by an efficient and intuitive approach. As the feed position error will lower the telescope gain, this influence is analyzed in detail. In the end, it is concluded that the design of the mechanism can meet the requirement of the telescope performance. Xiaoming Chai, Jin Fan, Lanchuan Zhou, and Bo Peng Copyright © 2014 Xiaoming Chai et al. All rights reserved. Optimization of a Centrifugal Boiler Circulating Pump’s Casing Based on CFD and FEM Analyses Wed, 16 Apr 2014 09:35:07 +0000 http://www.hindawi.com/journals/ame/2014/532892/ It is important to evaluate the economic efficiency of boiler circulating pumps in manufacturing process from the manufacturers’ point of view. The possibility of optimizing the pump casing with respect to structural pressure integrity and hydraulic performance was discussed. CFD analyses of pump models with different pump casing sizes were firstly carried out for the hydraulic performance evaluation. The effects of the working temperature and the sealing ring on the hydraulic efficiency were discussed. A model with casing diameter of 0.875 was selected for further analyses. FEM analyses were then carried out on different combinations of casing sizes, casing wall thickness, and materials, to evaluate its safety related to pressure integrity, with respect to both static and fatigue strength analyses. Two models with forging and cast materials were selected as final results. Zhigang Zuo, Shuhong Liu, Yizhang Fan, and Yulin Wu Copyright © 2014 Zhigang Zuo et al. All rights reserved. Prediction and Experimental Validation of Cutting Force for Bull-Nose End Mills with Lead Angle Wed, 16 Apr 2014 07:20:09 +0000 http://www.hindawi.com/journals/ame/2014/650215/ This study focuses on cutting force predictions with the tool-workpiece inclination angle in bull-nose milling based on the semimechanistic force model. By analyzing kinematics and mechanics of the bull-nose end mills during cutting, force expressions including lead angle are stated and the model is exerted on each discrete element as oblique cutting with coordinate transformation and numerical integration to obtain the dynamic cutting force components. An improved identification method considering speed variations along the tool axis is applied to calibrate coefficients. Coefficients are regarded as the function of each elemental elevation. Then, a geometry-based method to acquire cutter workpiece engagement (CWE) is proposed. Also acquisition of accurate start and exit angles on each slice is deliberated elaborately for cutters with lead or tilt angle in milling processes. Thereby, to verify the validity of the force prediction model and start-exit angle acquisition method, experiments with variable lead angles are conducted under different axial immersions. The results reveal that the presented model and approaches can predict cutting forces with high accuracy. Finally, the cutting force components under different cutter postures and conditions are analyzed to provide instructions for parameter selections. Baohai Wu, Ge Gao, Ming Luo, and Gongnan Xie Copyright © 2014 Baohai Wu et al. All rights reserved. Design and Experiment of a Differential-Based Power Split Device Wed, 16 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/981396/ Hybrid electric vehicles have excellent energy efficiency and emission performance. Power split device (PSD) is a key component that directly affects the control strategy of power systems, the economic consumption of fuel, and the dynamic performance of vehicles. A differential-based PSD was proposed in this paper. A traditional differential was taken as the prototype and a new design method is proposed to retrofit the differential into a PSD. First, a comprehensive approach that includes theoretical analysis and software simulation was used to analyze the possibility as well as the necessity of retrofitting the differential into PSD. Then the differential was retrofitted. Finally, finite element analysis and bench test were conducted. Results showed that applying the retrofitted differential as PSD is practicable. Xiaohua Zeng, Yujun Peng, Dafeng Song, Shuai Zheng, Zhongda Wang, and Nannan Yang Copyright © 2014 Xiaohua Zeng et al. All rights reserved. Application Study of Edge Detection for Droplet in Laser Enhanced GMAW Welding Tue, 15 Apr 2014 16:38:46 +0000 http://www.hindawi.com/journals/ame/2014/952605/ Ambient pressure has a certain inhibiting effect on underwater welding droplet transfer and the stability of welding process. Good droplet transfer of underwater welding plays an important role in improving repairing quality of underwater structures. As an additional droplet separating force, laser provides effective means in improving the welding quality. For quantitative analysis and comparison of laser enhanced effect on droplet transfer, a high-speed camera system to shoot the process of welding droplet transfer was designed and by adopting the frequency domain operation, a filter aiming at image processing of welding droplet was also designed to filter the ambient noise and diffraction fringe. Through edge detection algorithm, edges of droplet images were detected, and the size of droplet was computed accurately with welding wire as the reference. At last, droplets’ statues under different welding parameters were compared. The results show that the clear images of GMAW droplet separated from the noise background can be acquired, which makes the high-precision quantitative analysis of laser enhanced effect possible. All of the results lay a foundation for further test of laser enhanced hyperbaric underwater welding. Zhu Jialei, Jiao Xiangdong, and Qiao Xi Copyright © 2014 Zhu Jialei et al. All rights reserved. Optimal Design of a 3-DOF Cable-Driven Upper Arm Exoskeleton Tue, 15 Apr 2014 11:28:38 +0000 http://www.hindawi.com/journals/ame/2014/157096/ With outstanding advantages, such as large workspace, flexibility, and lightweight and low inertia, cable-driven parallel manipulator shows great potential for application as the exoskeleton rehabilitation robot. However, the optimal design is still a challenging problem to be solved. In this paper, the optimal design of a 3-DOF (3-degree-of-freedom) cable-driven upper arm exoskeleton is accomplished considering the force exerted on the arm. After analysis of the working conditions, two promising configurations of the cable-driven upper arm exoskeleton are put forward and design parameters are simplified. Then, candidate ranges of two angle parameters are determined with the proposed main workspace requirement. Further, global force indices are defined to evaluate the force applied to the arm by the exoskeleton, in order to enhance the system safety and comfort. Finally, the optimal design of each configuration is obtained with proposed force indices. In addition, atlases and charts given in this paper well illustrate trends of workspace and force with different values of design parameters. Zhu-Feng Shao, Xiaoqiang Tang, and Wangmin Yi Copyright © 2014 Zhu-Feng Shao et al. All rights reserved. Single-Sided Electromagnetic Induction Heating Based on IGBT Tue, 15 Apr 2014 11:28:29 +0000 http://www.hindawi.com/journals/ame/2014/503849/ A single-sided induction heating system based on IGBT is proposed. The system includes the series resonant circuit, control circuit, and auxiliary circuit. The main circuit includes rectifier, filter, inverter, and resonant circuit. A drive circuit is designed for IGBT combing some protection circuits. We have a simulation of the single-sided induction heating system in ANSYS. The simulation results are compared with the experimental results. The performance of the system is promising. And also we estimate the temperature distribution model by the least squares theory. Song Wang, Guangda Li, and Xiaokun Li Copyright © 2014 Song Wang et al. All rights reserved. High Temperature Gas-to-Gas Heat Exchanger Based on a Solid Intermediate Medium Tue, 15 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/353586/ This paper proposes the design of an innovative high temperature gas-to-gas heat exchanger based on solid particles as intermediate medium, with application in medium and large scale externally fired combined power plants fed by alternative and dirty fuels, such as biomass and coal. An optimization procedure, performed by means of a genetic algorithm combined with computational fluid dynamics (CFD) analysis, is employed for the design of the heat exchanger: the goal is the minimization of its size for an assigned heat exchanger efficiency. Two cases, corresponding to efficiencies equal to 80% and 90%, are considered. The scientific and technical difficulties for the realization of the heat exchanger are also faced up; in particular, this work focuses on the development both of a pressurization device, which is needed to move the solid particles within the heat exchanger, and of a pneumatic conveyor, which is required to deliver back the particles from the bottom to the top of the plant in order to realize a continuous operation mode. An analytical approach and a thorough experimental campaign are proposed to analyze the proposed systems and to evaluate the associated energy losses. R. Amirante and P. Tamburrano Copyright © 2014 R. Amirante and P. Tamburrano. All rights reserved. The Effect of Atom Vacancy Defect on the Vibrational Behavior of Single-Walled Carbon Nanotubes: A Structural Mechanics Approach Mon, 14 Apr 2014 11:37:13 +0000 http://www.hindawi.com/journals/ame/2014/291645/ An atomistic structural mechanics method, which is based on the exclusive use of spring elements, is developed in order to study the effect of imperfections due to atom vacancy on the vibrational characteristics of single-walled carbon nanotubes (SWCNTs). The developed elements simulate the relative translations and rotations between atoms as well as the mass of the atoms. In this way, molecular mechanics theory can be applied directly because the atomic bonds are modeled by using exclusively physical variables such as bond stretching. The method is validated for its predictability comparing with vibration results found in the open literature for pristine nanotubes. Then, it is used for the vibration analysis of defective nanotubes. Imperfections such as one-atom vacancy, two-atom vacancy, and one carbon hexagonal cell vacancy are investigated. Their effect on vibrational behavior is explored for different defect positions, nanotube diameters, and support conditions. According to the obtained results, the fundamental frequency is decreased as the size of imperfection increases, and the percentage reduction in fundamental frequency due to the atomic vacancy defect is more affected for a single-clamped SWCNT than for a double-clamped one. S. K. Georgantzinos, G. I. Giannopoulos, and N. K. Anifantis Copyright © 2014 S. K. Georgantzinos et al. All rights reserved. Multiphase Flow System with Suspended Particles Mon, 14 Apr 2014 08:19:57 +0000 http://www.hindawi.com/journals/ame/2014/792050/ Guan Heng Yeoh, Dirk Lucas, Sherman Chi Pok Cheung, and Jiyuan Tu Copyright © 2014 Guan Heng Yeoh et al. All rights reserved. A Novel Approach of Low-Light Image Denoising for Face Recognition Mon, 14 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/256790/ Illumination variation makes automatic face recognition a challenging task, especially in low light environments. A very simple and efficient novel low-light image denoising of low frequency noise (DeLFN) is proposed. The noise frequency distribution of low-light images is presented based on massive experimental results. The low and very low frequency noise are dominant in low light conditions. DeLFN is a three-level image denoising method. The first level denoises mixed noises by histogram equalization (HE) to improve overall contrast. The second level denoises low frequency noise by logarithmic transformation (LOG) to enhance the image detail. The third level denoises residual very low frequency noise by high-pass filtering to recover more features of the true images. The PCA (Principal Component Analysis) recognition method is applied to test recognition rate of the preprocessed face images with DeLFN. DeLFN are compared with several representative illumination preprocessing methods on the Yale Face Database B, the Extended Yale face database B, and the CMU PIE face database, respectively. DeLFN not only outperformed other algorithms in improving visual quality and face recognition rate, but also is simpler and computationally efficient for real time applications. Yimei Kang and Wang Pan Copyright © 2014 Yimei Kang and Wang Pan. All rights reserved. Research on High Speed Cutting Parameter Optimization and Fault Diagnosis Technology Thu, 10 Apr 2014 17:27:03 +0000 http://www.hindawi.com/journals/ame/2014/281216/ High speed cutting process is a very complicated process; cutting parameters have a significant effect on cutting process and play a key role in the process of product manufacturing. The overall scheme of high speed cutting parameter optimization and its fault diagnosis have been introduced. The mathematical model of the selected cutting parameters was established and the optimized parameters were obtained by combining the experimental design with the technology of data processing. The statistical description of high speed cutting process control was introduced and the fault diagnosis model of cutting parameter optimization by using the neural network was proposed. Finally, the mathematical model in the present study is validated with a numerical example. The results show that the present method solved the problem of poor universality of high speed cutting data effectively and avoided the inaccuracy of physical and chemical mechanism research. Meanwhile, the present study prevents the passive checks of the cutting and gets better diagnosis of the complicated cutting fault type. Honggen Zhou, Xuwen Jing, Lei Wang, Kaiyun Dai, and Jia Yongpeng Copyright © 2014 Honggen Zhou et al. All rights reserved. Application of Nondimensional Dynamic Influence Function Method for Eigenmode Analysis of Two-Dimensional Acoustic Cavities Thu, 10 Apr 2014 08:12:14 +0000 http://www.hindawi.com/journals/ame/2014/363570/ This paper establishes an improved NDIF method for the eigenvalue extraction of two-dimensional acoustic cavities with arbitrary shapes. The NDIF method, which was introduced by the authors in 1999, gives highly accurate eigenvalues despite employing a small number of nodes. However, it needs the inefficient procedure of calculating the singularity of a system matrix in the frequency range of interest for extracting eigenvalues and mode shapes. The paper proposes a practical approach for overcoming the inefficient procedure by making the final system matrix equation of the NDIF method into a form of algebraic eigenvalue problem. The solution quality of the proposed method is investigated by obtaining the eigenvalues and mode shapes of a circular, a rectangular, and an arbitrarily shaped cavity. S. W. Kang and S. N. Atluri Copyright © 2014 S. W. Kang and S. N. Atluri. All rights reserved. Soft Robotic Manipulation of Onions and Artichokes in the Food Industry Thu, 10 Apr 2014 06:45:31 +0000 http://www.hindawi.com/journals/ame/2014/345291/ This paper presents the development of a robotic solution for a problem of fast manipulation and handling of onions or artichokes in the food industry. The complete solution consists of a parallel robotic manipulatior, a specially designed end-effector based on a customized vacuum suction cup, and a computer vision software developed for pick and place operations. First, the selection and design process of the proposed robotic solution to fit with the initial requeriments is presented, including the customized vacuum suction cup. Then, the kinematic analysis of the parallel manipulator needed to develop the robot control system is reviewed. Moreover, computer vision application is presented in the paper. Hardware details of the implementation of the building prototype are also shown. Finally, conclusions and future work show the current status of the project. R. Morales, F. J. Badesa, N. Garcia-Aracil, J. M. Sabater, and L. Zollo Copyright © 2014 R. Morales et al. All rights reserved. Study on Energy Efficiency Improvement of a Heat Pump Dryer during the Early Stage of Drying Frozen Hot Peppers Thu, 10 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/745918/ During an early stage of drying frozen peppers, an electric heater is often used for elevating the temperature of a drying chamber to a certain temperature due to liquid back of the compressor or frosting at the evaporator. Therefore, it is necessary to devise an energy-efficient method to replace or less use electric heaters since they have very low energy efficiency. Also, to shorten drying time, it is essential to rapidly elevate the chamber temperature. In this study, a set of performance tests using hot bypass gas, air dampers, external evaporators, and radiators has been tried to lower the operating temperature of the heat pump dryer as well as to decrease the temperature-elevating time. According to the test results, hot bypass gas is beneficial in increasing the energy efficiency by lowering the initial operating temperature of the heat pump to 3°C. Furthermore, air dampers, external evaporators, and radiators can greatly improve the rate of temperature elevation. When compared with the temperature elevation rate of the standard dryer, 4.1°C/h, an external evaporator can improve elevation rate by 78%, air dampers by 93%, and radiators by 45%. Y. L. Lee, S. J. Park, and I. S. Hwang Copyright © 2014 Y. L. Lee et al. All rights reserved. Tool Wear and Formation Mechanism of White Layer When Hard Milling H13 Steel under Different Cooling/Lubrication Conditions Thu, 10 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/949308/ The present work aims at revealing the formation mechanism of white layer and understanding the effects of tool wear and cooling/lubrication condition on white layer when hard milling H13 steel with coated cutting tools. Hard milling experiments were carried out, and tool wear and its effect on formation of white layer were investigated. Compared to dry cutting condition, CMQL (cryogenic minimum quantity lubrication) technique can obviously reduce tool wear and prolong tool life owing to its good cooling and lubrication properties. The optical images of the subsurface materials indicate that the formation of white layer is related to tool wear; moreover, the thickness of white layer increases with the increase of tool wear. SEM (scanning electron microscope) images and XRD (X-ray diffraction) analysis confirm that the formation of white layer is mainly due to the mechanical effect rather than the thermal effect. It also proves that white layer is partly decreased or can be totally eliminated by optimizing process parameters under CMQL cutting condition. CMQL technique has the potential to be used for achieving prolonged tool life and enhanced surface integrity. Song Zhang, Jianfeng Li, and Honggang Lv Copyright © 2014 Song Zhang et al. All rights reserved. Smooth and Accurate Trajectory Planning for Industrial Robots Thu, 10 Apr 2014 00:00:00 +0000 http://www.hindawi.com/journals/ame/2014/342137/ This paper proposes a smooth and accurate trajectory planning for industrial robots using geodesics. The workspace of a robot is split into positional and orientational parts. A Riemannian metric is given on each space such that the desired motion is a geodesic for the given metric. By regarding joint variables as local coordinates of the position space and the orientation space, Cartesian trajectories are represented by joint trajectories. A smooth and accurate motion of the robot end-effector and smooth joint trajectories corresponding to the motion can be obtained by calculating geodesics on the position space and the orientation space. To demonstrate the effectiveness of the proposed method, simulation experiments are conducted using the PUMA 560 robot. Youdong Chen, Ling Li, and Xudong Ji Copyright © 2014 Youdong Chen et al. All rights reserved.