Advances in Mechanical Engineering The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Lateral Stability Control of 4WD Vehicle considering Ride Performance Wed, 20 Aug 2014 07:32:27 +0000 In order to improve the lateral stability of 4WD vehicle and guarantee its ride performance, this study designs target yaw control system based on sliding mode variable structure control, proposes driving torque distribution control algorithm based on the response of vehicle stable steering characteristic, and designs semiactive suspension control system based on double-fuzzy controller. The control performance is analyzed during the step steering and the split-μ road turning. The results indicate that the combined control system is able to improve the lateral stability of this 4WD vehicle during turning, reduce its body vibration acceleration and suspension dynamic deflection during travelling on bumpy and uneven road, guarantee its dynamic property, and improve its comprehensive performance. Jianjun Hu, Bin Huo, Zhenhui Yang, and Hui Liu Copyright © 2014 Jianjun Hu et al. All rights reserved. Forward and Reverse Movements of a Linear Positioning Stage Based on the Parasitic Motion Principle Wed, 20 Aug 2014 06:10:41 +0000 A compact linear positioning stage using one microgripper and one piezoelectric stack is presented based on the parasitic motion principle. Characteristics of the linear positioning stage along the positive y-axis and the negative y-axis are measured and compared with each other. Experimental results indicate that the linear positioning stage has features of the large motion range, various movement velocities and stepping displacement, and forward and reverse movements. Meanwhile, the positioning stage has good resolution and enough load capacity. Possible reasons leading to nonlinearity and velocity difference between forward and reverse movements are discussed. Research results in this paper will make applications of the parasitic motion principle more flexible. Hu Huang and Hongwei Zhao Copyright © 2014 Hu Huang and Hongwei Zhao. All rights reserved. Performance Assessment of Low-Temperature Thermal Storage with Electromagnetic Control Wed, 20 Aug 2014 05:20:55 +0000 This study presents electromagnetic-controlled thermal storage (ECTS) that can be directly implemented in strategies of low-temperature waste heat recovery for energy-consuming equipment. A magnetic nanofluid (MNF) prepared from fine iron ferrite ferromagnetic particles is recommended as a latent heat medium (LHM). During electromagnetic induction, local flow fluctuations are generated and thermal convection in the MNF can be enhanced. The achieved results demonstrated that ECTS has a wide operational range and an optimum storage efficiency of 84.46%. Thus, a self-perturbation mode used to enhance thermal energy transportation can be designed for numerous waste heat management applications. Ya-Wei Lee Copyright © 2014 Ya-Wei Lee. All rights reserved. Rapid Evaluation for Position-Dependent Dynamics of a 3-DOF PKM Module Wed, 20 Aug 2014 00:00:00 +0000 Based on the substructure synthesis and modal reduction technique, a computationally efficient elastodynamic model for a fully flexible 3-RPS parallel kinematic machine (PKM) tool is proposed, in which the frequency response function (FRF) at the end of the tool can be obtained at any given position throughout its workspace. In the proposed elastodynamic model, the whole system is divided into a moving platform subsystem and three identical RPS limb subsystems, in which all joint compliances are included. The spherical joint and the revolute joint are treated as lumped virtual springs with equal stiffness; the platform is treated as a rigid body and the RPS limbs are modelled with modal reduction techniques. With the compatibility conditions at interfaces between the limbs and the platform, an analytical system governing differential equation is derived. Based on the derived model, the position-dependent dynamic characteristics such as natural frequencies, mode shapes, and FRFs of the 3-RPS PKM are simulated. The simulation results indicate that the distributions of natural frequencies throughout the workspace are strongly dependant on mechanism’s configurations and demonstrate an axial-symmetric tendency. The following finite element analysis and modal tests both validate the analytical results of natural frequencies, mode shapes, and the FRFs. Hai-wei Luo, Hui Wang, Jun Zhang, and Qi Li Copyright © 2014 Hai-wei Luo et al. All rights reserved. Vibroacoustic Modeling and Path Control of Air-Borne Axle Whine Noise Wed, 20 Aug 2014 00:00:00 +0000 The axle whine noise will eventually affect the vehicle noise performance. In this study, a systematic modeling approach is developed to analyze the axle whine problem by considering the hypoid gear mesh from the tooth contact process as well as the system dynamics effect with gear design parameters and shaft-bearing-housing system taken into account. Moreover, the tuning of the dominant air-borne path is modeled analytically by using the sound transmission loss idea. First, gear tooth load distribution results are obtained in a 3-dimensional loaded tooth contact analysis program. Then mesh parameters are synthesized and applied to a linear multibody gear dynamic model to obtain dynamic mesh and bearing responses. The bearing responses are used as the excitation force to a housing finite element model. Finally, the vibroacoustic analysis of the axle is performed using the boundary element method; sound pressure responses in the axle surface are then simulated. Transmission losses of different panel partitions are included in the final stage to guide the tuning of air-borne paths to reduce the radiated axle whine noise. The proposed approach gives a more in-depth understanding of the axle whine generation and therefore can further facilitate the system design and trouble-shooting. Dong Guo and Guohua Sun Copyright © 2014 Dong Guo and Guohua Sun. All rights reserved. Determination of Coined-Bead Geometry in the V-Bending Process Wed, 20 Aug 2014 00:00:00 +0000 The coined-bead technique is commonly applied in the V-bending process to eliminate the spring-back feature and to achieve the required bending angle. In the present research, which is based on a stress distribution analysis, the effects of a coined-bead geometry in the V-bending process on the increased compressive stress in the bending allowance zone and on the increased reversed bending zone in the leg of the workpiece were observed and characterized. The research also illustrated the variations in spring-back and spring-go characteristics for different coined-bead widths and heights. As the bead width increased, the spring-go decreased, increased, and decreased again for different simulated bead heights and workpiece materials. The research was able to disprove previously suggested theories for coined-beaded V-bending, which suggested that a smaller bead width should be applied to cancel out the spring-back characteristic. In addition, the spring-back characteristic returned when an oversized bead width was applied. Therefore, to achieve the required bending angle, the size of the bead width was optimized both to provide a balance between a favorable stress distribution in the bending zone and reversed bending zone and to reduce the bending load. Wiriyakorn Phanitwong and Sutasn Thipprakmas Copyright © 2014 Wiriyakorn Phanitwong and Sutasn Thipprakmas. All rights reserved. Reliability Analysis of a Filtering Reducer under the Discrete Space Environmental Shocks Tue, 19 Aug 2014 12:07:12 +0000 Dynamic reliability analysis of a filtering reducer is performed by accounting for discrete shocks from the space environment. Gears are considered as the lumped mass and meanwhile the meshing between different gears is equivalent to a dynamic system consisting of springs and dampers during construction of the dynamic model. The Newmark method is employed to resolve differential equations, and then the additional acceleration could be obtained, caused by shocks to the filtering reducer. Dynamic reliability analysis is conducted with the help of the Simulink tool for the outputs. The results are hopefully useful for spacecraft mechanism design. Jing Lu, Zhonglai Wang, Wei Chen, Xuefei Zhang, and Hao Liu Copyright © 2014 Jing Lu et al. All rights reserved. The Impeller Improvement of the Centrifugal Pump Based on BVF Diagnostic Method Tue, 19 Aug 2014 07:29:55 +0000 Selecting one IS 150-125-250 centrifugal pump as reference model, impeller with 3D blades has been designed using two-dimensional theory. Numerical simulations using Reynolds averaged N-S equations with a RNG k-ε two-equation turbulence model and log-law wall function are used to estimate the hydraulic performance of pump and obtain BVF distributions on impeller blade pressure surfaces and suction surfaces. The results show that, compared with IS150-125-250 pump, the designed one shows better performance in a wide operation range with the maximal efficiency 2.8% increase. With the help of boundary vorticity flux diagnostic, further improvement is realized. Local defect areas on blade surfaces are identified and inlet blade angle distribution modification and wrapping angle change of designed impeller are carried out on local defect areas. The vortices that exist in designed impeller disappear after modification and it flows more smoothly in the modified impeller with slight hydraulic performance improvement than in the original designed one. BVF diagnostic can be further embedded in optimal design method to perform an automatic optimal design without manual trial-and-error procedures. Xin Zhou, Yongxue Zhang, Zhongli Ji, and Long Chen Copyright © 2014 Xin Zhou et al. All rights reserved. QoS-Aware Multiobjective Optimization Algorithm for Web Services Selection with Deadline and Budget Constraints Tue, 19 Aug 2014 07:09:58 +0000 The problem of QoS-aware multiobjective optimization is an important issue for Web services selection in distributed computing environment. In this paper, a novel algorithm called MOASS (multiobjective optimization algorithm for web service selection) is proposed through analyzing the genetic operators such as constraint handling, the initial population generation, fitness assignment, and diversity preservation. Compared with MOEAWP (Yu et al., 2007), simulation results show that the feasible objective region can be filled uniformly with the optimal solutions obtained by MOASS under different test applications. In the case of higher constraints especially, MOASS can obtain more high-quality and evenly distributed nondominated solutions than MOEAWP. Xianzhong Han, Yingchun Yuan, Chen Chen, and Kejian Wang Copyright © 2014 Xianzhong Han et al. All rights reserved. Mesoscopic Numerical Simulation of Stratified Rock Failure Using Digital Image Processing Mon, 18 Aug 2014 12:12:17 +0000 This paper presents a digital image processing (DIP) based finite difference method (FDM) and makes the first attempt to apply the new method to the failure process of stratified rocks from Chinese Jinping underground carves. In the method, the two-dimensional (2D) inhomogeneity and mesostructures of rock materials are first identified with the DIP technique. And then the binarization image information is used to generate the finite difference grids. Finally, the failure process of stratified rock samples under uniaxial compression condition is simulated by using the FDM. In the DIP, an image segmentation algorithm based on seeded region growing (SRG) is proposed, instead of the traditional threshold value method. And with the new method, we can fully acquire the inhomogeneous distributions and mesostructures of stratified rocks. The simulated macroscopic mechanical behaviors are in good agreement with the laboratory experimental observation. Numerical results show that the proposed DIP based FDM is suitable for the failure analysis of stratified rocks because it can fully take into account the material heterogeneity, and the anisotropy of stratified rocks is also disposed to some extent. Ang Li, Guo-jian Shao, Tian-tang Yu, Jing-bo Su, and Sheng-yong Ding Copyright © 2014 Ang Li et al. All rights reserved. A New Method of Improving Low-Speed Performance of Variable Speed Hydraulic Systems: By Leaking Parallel Valve Control Mon, 18 Aug 2014 11:16:38 +0000 Aiming at improving low-speed performance of variable speed hydraulic systems, the leaking parallel valve control is applied to the system during low-speed period. This method increases system damping ratios by increasing leakage controlled by the valve. In addition, the increase of damping ratios just compensates the reduction of damping ratios due to the friction negative slop, which helps to improve low-speed stability and achieve lower critical speed. In the whole process of closed loop control, the system in leaking parallel valve control has good speed performance with more stable and suitable damping ratios and basically avoids pressure impact at start and stop stages and still keeps comparatively high efficiency because the pump provides total flow and the valve only leaks out few flows. Haigang Ding and Jiyun Zhao Copyright © 2014 Haigang Ding and Jiyun Zhao. All rights reserved. Optimal Design of Multistage Two-Dimensional Cellular-Cored Sandwich Panel Heat Exchanger Mon, 18 Aug 2014 09:33:03 +0000 For a two-dimensional (2D) cellular-cored sandwich panel heat exchanger, there exists an optimum cell size to achieve the maximum heat transfer with the prescribed pressure drop when the length is fixed and the two plates are isothermal. However, in engineering design, it is difficult to find 2D cellular materials with the ideal cell size because the cell size selected must be from those commercially available, which are discrete, not continuous. In order to obtain the maximum heat dissipation, an innovative design scheme is proposed for the sandwich panel heat exchanger which is divided into multiple stages in the direction of fluid flow where the 2D cellular material in each stage has a specific cell size. An analytical model is presented to evaluate the thermal performance of the multistage sandwich panel heat exchanger when all 2D cellular materials have the same porosity. Also, a new parameter named equivalent cell size (ECS) is defined, which is dependent on the cell size and length of cellular material in all stages. Results show that the maximum heat dissipation design of the multistage sandwich panel heat exchanger can be converted to make the ECS equal to the optimal cell size of the single-stage exchanger. Yongcun Zhang and Shutian Liu Copyright © 2014 Yongcun Zhang and Shutian Liu. All rights reserved. Determination of the Thermal Insulation for the Model Building Approach and the Global Effects in Turkey Thu, 14 Aug 2014 15:39:39 +0000 One of the most important considerations to be considered in the design of energy efficient buildings is the thickness of the insulation to be applied to the building. In this study the existing building stock in Turkey has been investigated depending on parameters such as the height and the area. A model building has been created covering all of these buildings. Fuel emission reduction of combustion system was calculated in the case of insulation applied to this model building. Heat loss of the existing building stock and exhaust emissions and the contribution to the country's economy with the model building methodology are also determined. The results show that the optimum insulation thicknesses vary between 3.21 and 7.12 cm, the energy savings vary between 9.23 US$/m2 and 43.95 US$/m2, and the payback periods vary between 1 and 8.8 years depending on the regions. As a result of the study when the optimum insulation thickness is applied in the model building, the total energy savings for the country are calculated to be 41.7 billion US$. And also total CO2 emissions for the country are calculated to be 57.2 billion kg CO2 per year after insulation. Cenk Onan Copyright © 2014 Cenk Onan. All rights reserved. Design and Implementation of an AHRS Based on MEMS Sensors and Complementary Filtering Thu, 14 Aug 2014 11:53:41 +0000 This paper presents design and implementation of an attitude and heading reference system (AHRS) based on low-cost MEMS sensors and complementary filtering (CF). Different from traditional solutions, information fusion is performed with Euler angles directly, which is more straightforward for understanding; however it proposes many challenges for reaching a stable and accurate estimation as when these angles approach or traverse their range boundaries, estimation may get discontinuous. Thus an effective discontinuity avoiding strategy is suggested in this paper to refine the estimation. Besides, instead of extended Kalman filtering (EKF), CF is utilized for state estimation of AHRS as it features fusion of high-frequency and low-frequency signals. In order to make up for shortcomings of MEMS sensors such as multiple errors, drifts, and bad accuracy, some effective calibration and filtering algorithms are proposed to guarantee agreeable AHRS performance. Also, architecture of the MEMS IMU (inertial measurement unit) and mathematical principles for AHRS solution are explained and implemented in this paper. Meanwhile, experimental comparisons have proved feasibility and acceptable performance of this AHRS design. Yangzhu Wang, Ning Li, Xi Chen, and Miao Liu Copyright © 2014 Yangzhu Wang et al. All rights reserved. Characteristics of a Tire Friction and Performances of a Braking in a High Speed Driving Thu, 14 Aug 2014 11:35:52 +0000 The goal of pavement is to deliver the fine roughness and the safe road surface to traffic. It requires a secured and comfortable surface using the controlled speed of road. Through adjusting driving speed, skid resistance can be altered in one of the performances of the pavement surface. In high speed driving, there might be a certain level of risk, not in the same level as the proposed roads. Hence, this study first analyzes the speed equation under a consideration of a braking distance and then suggests the friction coefficient in high speed driving with the principle of conservation of energy. If we accept simply that the coefficient of friction is independent of speed, the difference between analysis and test value for braking distance is greatly generated. Therefore we have to analyze the coefficient of friction as an exponential function of braking speed of a vehicle. Yumrak Oh and Hoguen Lee Copyright © 2014 Yumrak Oh and Hoguen Lee. All rights reserved. Sound Quality Evaluation and Optimization for Interior Noise of Rail Vehicle Wed, 13 Aug 2014 13:18:05 +0000 A procedure for sound filed simulation, sound quality (SQ) evaluation, and optimization of interior noise of a rail vehicle is investigated in this paper. Firstly, some interior noises are measured on site when the subway is running in tunnel at a speed of 60 km/h. The sound pressure levels (SPLs), loudness, sharpness, and roughness of the measured noise are analyzed. A finite element model for acoustical simulation of the carriage is established by using the Actran software. The accuracy and feasibility of the finite model are verified by comparing the psychoacoustical parameters from the simulations and measurements. By using orthogonal experimental design, finally, the best optimization scheme is put forward, which obtained a sound quality improvement with a 4.81 dB decrease in SPL and a 1.07 sone reduction in loudness. The proposed optimization scheme may be extended to other vehicles for improving interior acoustic environment. Kai Hu, Yansong Wang, Hui Guo, and Hao Chen Copyright © 2014 Kai Hu et al. All rights reserved. Thin-Plate Forming by Thixo- and Rheoforging Wed, 13 Aug 2014 11:51:37 +0000 Thin plates with a thickness of 1.2 mm are fabricated using two processes, thixoforging and rheoforging, which are semisolid forming techniques. The die design, formability, microstructure, and mechanical properties of the fabricated thin plates are analysed. A fan-shaped gate is designed by analysing the filling behaviour using semisolid material, and uniform filling behaviour of material is obtained by arranging nine overflows in product area. semisolid metal is prepared through a semisolid process in which reheating, a thixoprocess, and cooling with stirring, a rheoprocess, are applied. The semisolid material is injected into a forging die and is formed into thin plate at a punch speed of 300 mm/s and under a pressure of 100 MPa. Since semisolid material with a solid fraction below 45% has mainly small primary α-Al particles, the formability of the thin plate is improved. The formed thin plate also has good mechanical properties since the small and globular grains are evenly distributed. The thin plate formed from semisolid material with a solid fraction above 50% has poor mechanical properties owing to the large quantity of coarse primary α-Al particles. A rheoforged thin plate exhibits poorer mechanical properties than a thixoforged thin plate, but rheoforging produces a more precise thin plate. Chul Kyu Jin, Amir Bolouri, Chung Gil Kang, and Gyu Wan Hwang Copyright © 2014 Chul Kyu Jin et al. All rights reserved. A Literature Review of Approaches for Stick-Slip Vibration Suppression in Oilwell Drillstring Tue, 12 Aug 2014 12:51:30 +0000 Stick-slip vibration presents one of the main problems in the quality of drilling performance limiting tool life and productivity. This type of vibration can be suppressed by means of many approaches, such as varying parameters and use of control tools. Although tremendous improvements have been made in overcoming this dysfunction, stick-slip vibration suppression remains a large problem in the drilling industry. This paper provides an up-to-date review of stick-slip vibration behavior in drillstrings. First, the phenomena and the modeling methods of stick-slip vibrations are reviewed. Then an overview of the approaches for stick-slip suppression in oilwell drillstrings is presented, grouping the references under the categories of passive vibration control and active vibration control. Literature related to passive control is grouped under the categories of optimization of bottom hole assembly (BHA) configurations, bit selection and bit redesign, and use of downhole tools. The contributions related to the active control approaches for stick-slip mitigation are grouped under the categories of drilling parameters optimization based on real-time measurement and use of active control systems. Finally, related discussions and recommendations are conducted. Xiaohua Zhu, Liping Tang, and Qiming Yang Copyright © 2014 Xiaohua Zhu et al. All rights reserved. Numerical Analysis of Pressure Pulsation for a Bidirectional Pump under Positive and Reverse Operation Tue, 12 Aug 2014 10:50:49 +0000 Bidirectional pump holds great promise in a wide range of applications since it could realize the function of drainage and irrigation simultaneously. A bidirectional pump with high specific speed was designed and 10 groups of performance tests, under different setting angles, including both positive and negative directions, were conducted. Numerical simulations were then performed to analyze the variation principle of internal pressure pulsation in flow passage and both the front and the back sides of the blade and guide vane. Results show that the optimum operation point was shifted and the performance declined under reverse operation. The maximum pressure pulsation amplitude occurred to the vicinity of the blade’s inlet edge under both positive and negative operations. The main pulsation frequency was the blade passing frequency while it was four times of shaft rotation frequency in the rotatory zone, which was equal to the number of guide vanes. The guide vane has a significant effect on the pressure pulsation variation. The pulsation amplitude had a higher value while the pump was in its negative operation rather than positive. These results could provide valuable insight for reducing the pressure amplitudes in the bidirectional pump. Pengfei Ma, Jun Wang, and Hui Li Copyright © 2014 Pengfei Ma et al. All rights reserved. The Effect of Nanofluid Concentration on the Cooling System of Vehicles Radiator Tue, 12 Aug 2014 09:20:01 +0000 Experimental investigation on forced convection heat transfer is applied to vehicles’ radiator filled with AL2O3 water nanofluid with different concentrations: 0.1%, 0.5%, 1%, 1.5%, and 2% by volume. The experiments are done for three cases, each case corresponds to different heat load, coolant flow rate, and air flow rate to simulate the vehicle engine cooling system at various loads relevant to the cooling system of Toyota Yaris 2007. The coolant and air heat transfer coefficients, Nusselt numbers, heat rate lost by the coolant and absorbed by the air, heat exchanger effectiveness, overall heat transfer coefficients, Reynolds number, and the pumping power are calculated. Log mean temperature difference (LMTD) and effectiveness-number of transfer units (-NTU) are used to determine the outside air heat transfer coefficient. Results show gradual enhancement in the heat transfer with concentrations 0.1%, 0.5%, and 1% by volume (optimum at 1%); however deterioration occurs at concentrations 1.5% and 2%. M. Ali, A. M. El-Leathy, and Z. Al-Sofyany Copyright © 2014 M. Ali et al. All rights reserved. Determination Method of the Structure Size Intervals of Dynamic Distorted Model of Elastic Cantilever Thin Plate Tue, 12 Aug 2014 09:14:31 +0000 This study investigates the applicability of using distorted models to predict the dynamic characteristics of cantilever thin plates. The study provides necessary scaling laws and applicable structure size intervals which guide the design of distorted models. Comparing with the size effects of different vibration orders, the method of using governing equations is employed to establish the scaling laws between the model and the prototype. Both complete and partial similarities are discussed. Then a titanium alloy plate, which is commonly used, is analyzed as a prototype. The establishment of applicable structure size intervals is discussed, with the same vibration mode in the same order. Applicable intervals of distorted model under different orders are also obtained by using a numerical method. The boundary functions of applicable structure size intervals are investigated and the applicability of the scaling laws and intervals are verified by using experimental data. The analytical results indicate that distorted models that satisfied the applicable structure size intervals can predict the characteristics of prototype with good accuracy. Zhong Luo, Yunpeng Zhu, Xiaobing Chen, and Xueyan Zhao Copyright © 2014 Zhong Luo et al. All rights reserved. Research on Characteristic of the Vibration Spectral Entropy for Centrifugal Pump Tue, 12 Aug 2014 09:13:51 +0000 Hydraulic instability caused by flow separation, vortex, second flow, and other unstable flow conditions leads to operational instability, consumption of additional energy, and pump damage. Evaluating the degree of hydraulic instability and addressing the problem at an early stage are highly important. This study focuses on developing a measurement and evaluation method for hydraulic instability by nonintrusive vibration techniques. At the onset of hydraulic instability, the spectral structure of the vibration signal significantly changes, especially for some broadband characteristics. Spectral entropy is regarded as an indicator of hydraulic instability and is capable of evaluating the spectral structure of the signal. The spectral entropy of vibration is efficient and reflects the development of cavitation. Moreover, the positive slope area in the head-flow characteristic indicates the emergence of hydraulic instability. The spectral entropy is highly suited for online tests because of its dimensionless nature, and as compared with the root mean square value, a common dimensionless parameter, spectral entropy can highly coincide with energy characteristic. Yin Luo, Shouqi Yuan, Jianping Yuan, and Jiaxin Lu Copyright © 2014 Yin Luo et al. All rights reserved. Advances of Artificial Intelligence in Mechanical Engineering Tue, 12 Aug 2014 08:57:09 +0000 Siamak Talatahari, Shengyong Chen, Amir H. Gandomi, and Amir H. Alavi Copyright © 2014 Siamak Talatahari et al. All rights reserved. Design of a New 4-DOF Haptic Master Featuring Magnetorheological Fluid Thu, 07 Aug 2014 05:50:07 +0000 This work presents a novel 4-degree-of-freedom (4-DOF) haptic master using magnetorheological (MR) fluid which is applicable to a robot-assisted minimally invasive surgery (RMIS) system. By using MR fluid, the proposed haptic device can easily generate bidirectional repulsive torque along the directions of the required motions. The proposed master consists of two actuators: an MR bidirectional clutch associated with a planetary gear system and an MR clutch with a bevel gear system. After demonstrating the configuration, the torque models of MR actuators are mathematically derived based on the field-dependent Bingham model. An optimal design that accounts for spatial-limitation and the desired torque constraint is then undertaken. An optimization procedure based on finite element analysis is proposed to determine optimal geometric dimensions. Based on the design procedure, MR haptic master with the optimal parameters has been manufactured. In order to demonstrate the practical feasibility of the proposed haptic master, the field-dependent generating repulsive force is measured. In addition, a proportional-integral-derivative (PID) controller is empirically implemented to accomplish the desired torque trajectories. It has been shown that the proposed haptic master can track the desired torque trajectory without a significant error. Byung-Keun Song, Jong-Seok Oh, and Seung-Bok Choi Copyright © 2014 Byung-Keun Song et al. All rights reserved. Design and Motion Modeling of an Electromagnetic Hydraulic Power Hump Harvester Wed, 06 Aug 2014 11:22:34 +0000 This paper emphasises the idea that the kinetic energy getting wasted while vehicles move can be utilized to generate power by using a special arrangement called “hydraulic power hump.” Hydraulic technology is used to convert linear transient motion into rotational. Dynamic model for the new design has been derived and analyzed based on Lagrange differential equation. Governing differential equations are solved by numerical “Duhamel integral.” Theoretical simulations are carried out to study the features and estimation power. Guidelines are given for the design of this type of power speed humps. Hatem Hadi Obeid, Abdul Kareem Jaleel, and Nazar Aubays Hassan Copyright © 2014 Hatem Hadi Obeid et al. All rights reserved. Manufacturing of Porous Polycaprolactone Prepared with Different Particle Sizes and Infrared Laser Sintering Conditions: Microstructure and Mechanical Properties Wed, 06 Aug 2014 06:08:04 +0000 The techniques of Rapid Prototyping, also known as Additive Manufacturing, have prompted research into methods of manufacturing polymeric materials with controlled porosity. This paper presents the characterization of the structure and mechanical properties of porous polycaprolactone (PCL) fabricated by Selective Laser Sintering (SLS) using two different particle sizes and laser processing conditions. The results of this study indicated that it is possible to control the microstructure, that is, pore size and degree of porosity, of the polycaprolactone matrix using the SLS technique, by varying the particle size and laser energy density, obtaining materials suitable for different applications, scaffolds and drug delivery and fluid mechanical devices. The specimens manufactured with smaller particles and higher laser energy density showed a higher degree of sintering, flexural modulus, and fatigue resistance when compared with the other specimens. G. V. Salmoria, D. Hotza, P. Klauss, L. A. Kanis, and C. R. M. Roesler Copyright © 2014 G. V. Salmoria et al. All rights reserved. Research on Cavitation Regions of Upstream Pumping Mechanical Seal Based on Dynamic Mesh Technique Wed, 06 Aug 2014 00:00:00 +0000 In order to study the cavitation area of the Upstream Pumping Mechanical Seal, three-dimensional microgap inner flow field of the Upstream Pumping Mechanical Seal was simulated with multiphase flow cavitation model and dynamic mesh technique based on hydrodynamic lubrication theory. Furthermore, the simulated result was compared with the experimental data. The results show that the simulated result with the Zwart-Gerber-Belamri cavitation model was much closer to the experimental data. The area of cavitation inception mainly occurred at the concave side of the spiral groove and surrounding region without spiral grooves, which was nearly covered by the inner diameter to roots of grooves; in addition, the region near the surface of the stationary ring was primary cavitation location. The area of cavitation has little relationship with the medium pressure; however, it became larger following increasing rotating speed in the range of researched operating conditions. Moreover the boundary of cavitated area was transformed from smooth to rough, which occurred in similar film thickness. When cavitation number was decreasing, which was conducive to improving the lubrication performance of sealed auxiliary, it made the sealing stability decline. Huilong Chen, Qiangbo Wu, Cheng Xu, and Muzi Zuo Copyright © 2014 Huilong Chen et al. All rights reserved. Numerical Study on Improved Baffle in Compact Test Separator Tue, 05 Aug 2014 09:39:23 +0000 The aim of this paper is to design two improved baffles to solve the injection problem caused by traditional baffle in compact test separator and use FLUENT software to study their effects on separator pressure loss and separation efficiency. The result shows: that anti-injection baffle can make compact test separator with a high separation efficiency with a relatively low pressure loss. Also, the diameter of anti-injection plate which makes the compact test separator at its highest separation efficiency is slightly smaller than that which makes the lowest pressure loss. Yanhai Wei, Xinran Wang, Limin He, Shenghua Jiao, Guoqiang Zhang, Hao Cheng, Yujiang Li, and Tao Li Copyright © 2014 Yanhai Wei et al. All rights reserved. Calibration for Fuel Injection Parameters of the Diesel Engine Working at Plateau via Simulating Tue, 05 Aug 2014 08:48:51 +0000 In order to simulate the engine plateau characteristics, the 0-D Predictable Combustion Model Based on Neural Network was put forward firstly. Based on this combustion model, the integrated turbocharged diesel engine numerical model was established and then validated by experimental data. For the sake of improving engine performance at plateau, a measure is introduced in this study, which adapts the fuel injecting parameters at various altitude environments. And then the method to calibrate the injection parameters is proposed. Thus, three different simulating schemes at plateau environment had been put forward and the simulation results were compared later. Eventually, the outcome demonstrates that it is effective to advance injecting timing together with adjusting fuel mass; for instance, the rated power will recover to 89.7% of the plain value, once applying this adaption method at 4500 m altitude. Zhen-xia Zhu, Fu-jun Zhang, Chang-jiang Li, and Kai Han Copyright © 2014 Zhen-xia Zhu et al. All rights reserved. The Fabrication and Application of a PDMS Micro Through-Holes Mask in Electrochemical Micromanufacturing Tue, 05 Aug 2014 05:25:30 +0000 The electrochemical micromanufacturing process, as a key micromanufacturing technology, plays an important role in diverse industries. In this paper, polydimethylsiloxane (PDMS) is employed as a mask in the electrochemical micromanufacture of microstructures because of its chemical resistance, low cost, flexibility, and high molding capability. A new method for fabricating a PDMS micro through-holes mask is proposed. In this method, a thin resist film is employed to enhance the adhesion between the substrate and the SU-8 pillar array which is used as a mold. A vacuum-aided process is used to inject the PDMS gel into the SU-8 mold and the PDMS micro through-holes mask can be peeled off from the SU-8 mold when the gel is cured. Experiments were conducted to verify the feasibility of the proposed approach and PDMS microholes of various shapes were obtained. The PDMS mask can then be successfully applied in the electrochemical micromanufacturing process to generate microstructures and microdimple and embossment arrays have been successfully demonstrated. Furthermore, the PDMS mask can be reused, as it is not damaged during the manufacturing process. Xiaolei Chen, Ningsong Qu, Hansong Li, and Di Zhu Copyright © 2014 Xiaolei Chen et al. All rights reserved.