Advances in Mechanical Engineering The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Experimental Evaluation of Hysteretic Behavior of Rhombic Steel Plate Dampers Thu, 30 Oct 2014 08:12:28 +0000 Rhombic mild-steel plate damper (also named rhombic added damping and Stiffness (RADAS)) is a newly proposed and developed bending energy dissipation damper in recent years, and its mechanical properties, seismic behavior, and engineering application still need further investigations. In order to determine the basic mechanical performance of RADAS, fundamental material properties tests of three types of mild-steel specimen including domestically developed mild-steel material with low yield strength were carried out. Then, a quasistatic loading test was performed to evaluate the mechanical performance and hysteretic energy dissipation capacity of these rhombic mild-steel dampers manufactured by aforementioned three types of steel materials. Test results show that yield strength of domestically developed low yield strength steel (LYS) is remarkably lower than that of regular mild steel and its ultimate strain is also 1/3 larger than that of regular mild steel, indicating that the low yield strength steel has a favorable plastic deformation capability. The rhombic mild-steel plate damper with low yield strength steel material possesses smaller yield force and superior hysteretic energy dissipation capacity; thus they can be used to reduce engineering structural vibration and damage during strong earthquakes. Qiang Han, Junfeng Jia, Zigang Xu, Yulei Bai, and Nianhua Song Copyright © 2014 Qiang Han et al. All rights reserved. Effect of Relative Thickness on Improving Airfoil Aerodynamic Performance by Blunt Trailing-Edge Modification Wed, 29 Oct 2014 14:20:08 +0000 A numerical study on the aerodynamic performance of wind turbine airfoils and their modifications has been carried out to understand the effects of maximum relative thickness and its position on the lift enhancement of blunt trailing-edge modification. First, the airfoils (NACA4409, NACA4412, NACA4415, and NACA4418) with different relative thickness are modified to be symmetrical blunt trailing-edge airfoils with the software of XFOIL. Then, the lift and drag coefficients of NACA4412 airfoil are calculated using S-A and SST turbulence models, respectively. By comparing the numerical results with the experimental data, it is proved that the accuracy of SST model is higher than that of S-A model. Finally, the aerodynamic performance of the original and modified airfoils, based on the SST turbulence model, is investigated to analyze the increments of lift coefficient, drag coefficient, and lift-drag ratio. Results indicate that the increments of lift coefficient and lift-drag ratio increase first and then decrease with the increasing of maximum relative thickness. Furthermore, as the relative thickness position is gradually close to the leading-edge, the lift coefficient increment decreases, and the lift-drag ratio increment becomes almost negative. The investigated results can provide a reference for designing blunt trailing-edge airfoil of a wind turbine blade. Xu Zhang, Wei Li, and Chengcheng Kong Copyright © 2014 Xu Zhang et al. All rights reserved. The Influence of Inner Component and Topographical Properties on Tribological Parameters of Injection-Moulded Microparts Tue, 28 Oct 2014 07:00:16 +0000 Tribological parameters are dependent upon inter alia, inner component properties which may vary with the temperature-time behaviour of the polymer melt used. This temperature-time behaviour can be influenced by dynamic mould temperature control. The present paper presents a new dynamic tempering concept, which enables a targeted temperature-time control via shifting a mould cavity within two different tempered mould areas at a defined point in time. By influencing the temperature-time development by means of a mould temperature and isothermal holding time variation, micro tensile bars with different inner component properties are produced. To show the influence of inner component properties on tribological parameters, pin-on-disc wear tests are performed. Furthermore, tribological tests with different surface topographies are performed to show the influence of topographical properties on tribological parameters. Results indicate that the tribological properties of microparts are mainly influenced by the nature of the skin near layers, which can be influenced by the application of different mould temperatures. Variations in the isothermal holding time show no significant impact on the material examined. A more distinct roughness of the disc surface topography not only shows higher values for the measured tribological parameters but also different wear behaviour in general. Christopher Fischer and Dietmar Drummer Copyright © 2014 Christopher Fischer and Dietmar Drummer. All rights reserved. Analytical Model of Rain-Wind Induced Vibration of High-Voltage Transmission Line Mon, 27 Oct 2014 12:14:51 +0000 Under rainfall conditions, rain-wind induced vibration occurs on high-voltage transmission line occasionally. This phenomenon is caused by raindrops hitting the high-voltage conductor with a certain velocity and suspends to the bottom surface of the high-voltage conductor. By action of wind velocity and high-voltage conductor’s motion, some suspended raindrops will be blown away or shaken off. The remaining water may be reformed as upper rivulet and lower rivulet. Like the effect of icing galloping, this type of vibration can cause metal fatigue on fittings and towers, while its mechanism remains unknown. The objective of this paper is to validate an analytical model of rain-wind induced vibration of the high-voltage transmission line and to investigate the effect of wind velocity, rivulet motion, raindrop velocity, and time varying mass on the vibration amplitude. Taking Tuo-chang transmission line as an example, the analytical model is solved by Galerkin weighted residual method and central difference method. The numerical results are in agreement with the experimental data available in the literature. The analytical model enables more comprehensive understanding of the rain-wind induced vibration mechanism. Chao Zhou and Yibing Liu Copyright © 2014 Chao Zhou and Yibing Liu. All rights reserved. Modelling an EDM Process Using Multilayer Perceptron Network, RSM, and High-Order Polynomial Mon, 27 Oct 2014 09:46:54 +0000 Owing to the inadequacy of modelling electrical discharge machining (EDM) processes based on physical laws, three empirical modelling methods have been adopted in this study, namely, multilayer perceptron (MLP), response surface models (RSM), and high-order polynomials (HOP). To date, no publications regarding the use of the latter approach were found in the literature for modelling EDM processes; there were however some related to the approximation quality of RSM versus that of MLP networks but no investigations assessing the performance of the latter method against HOP. This study attempts to fill this gap by comparing the performance of the three methods mentioned above when modelling an EDM process with a WC-Co workpiece material. Three models were developed to correlate the material removal rate (MRR) with current, on-time, off-time, and capacitance. The half-normal plot and analysis of variance were used to test the significance of the investigated parameters. Due to the complex interdependence pattern that current and pulse on-time exhibited, the approximation of RSM was poor while that of the HOP and MLP models was adequate. A confirmation run based on new factor levels was performed to test the models’ generalization. The performance of the HOP model was marginally inferior to that of the MLP, but based on the paired -test, both models performed equally well. Khalid A. Al-Ghamdi and Elaine Aspinwall Copyright © 2014 Khalid A. Al-Ghamdi and Elaine Aspinwall. All rights reserved. Robotic System Development for Cooperative Orthopedic Drilling Assistance Thu, 23 Oct 2014 11:56:41 +0000 This paper describes a robotic bone drilling and screwing system for applications in orthopedic surgery. The goal is to realize two robot manipulators performing cooperative bone drilling. The proposed cooperative bone drilling system can be divided into hardware and software development. The hardware development section consists of two robot manipulator arms, which perform drilling and gripping of the bone, and operates using two joysticks. The software section assists the surgeon in visual and navigation control of those robot manipulators. Controller used in this system can be included in the hardware and software sections. Disturbance observer based position control was used in the robot manipulator maneuver and reposition controller (cooperative control) was used in cooperative drilling operation to maintain the alignment of the drill bit during drilling. A mathematical model for the control system was designed and a real environment mimicking simulation for bone drilling was designed. The result of the simulation shows that the cooperative robot system managed to perform cooperative drilling when misalignment occurs during bone drilling. The bone gripping robot managed to restore the drill bit to its ideal alignment in every event of misalignment in the drilling axis. Therefore this cooperative system has potential application in experimental orthopedic surgery. Vijayabaskar Kasi, Saad Mekhilef, R. A. R. Ghazilla, and Norhafizan Ahmad Copyright © 2014 Vijayabaskar Kasi et al. All rights reserved. A Two-DOF Fast Tool Servo for Optical Freeform Surfaces Diamond Turning Wed, 22 Oct 2014 07:38:42 +0000 Fast tool servo (FTS) technology is considered as the most popular technology to fabricate freeform optical lenses and micro- and nano-structured surfaces. Aiming at the disadvantages of existing single DOF FTS systems, this paper described a two-DOF FTS. Cross shape flexure hinges are designed as the guide mechanism, and two voice coil motors (VCMs) are selected to drive the tool motion. The FTS offline performance is tested, and the following error is about less than 0.1 μm; the motion resolution is 0.05 μm. A sinusoidal surface is machined to verify the cutting performance of the novel FTS, and the surface roughness is Ra 27 nm. The test results show that the two-DOF FTS system works well on the fabrication of optical freeform surfaces. Qiang Liu, Xiaoqin Zhou, Pengzi Xu, and Xu Zhang Copyright © 2014 Qiang Liu et al. All rights reserved. A Model to Determine Mesh Characteristics in a Gear Pair with Tooth Profile Error Tue, 21 Oct 2014 08:44:40 +0000 A method to determine the gear mesh stiffness, loaded transmission error, and tooth contact stress is presented with tooth profile error. The single tooth stiffness is calculated by the potential energy method. Contact stress is studied by the classic Hertzian elastic contact theory. Then two cases are presented for validation of the gear mesh stiffness model. It is demonstrated that the gear mesh stiffness model is effective for the gear pair with or without lead crown relief and tip and root relief. Finally, the effects of tooth lead crown relief and applied torque on the gear mesh stiffness are analyzed. The results show that mesh stiffness decreases and loaded transmission error and the maximum tooth contact stress grow with increasing the tooth lead crown relief. And mesh stiffness, loaded transmission error, and the maximum contact stress increase in a certain range as the applied torque increases for the tooth with lead crown relief. Qibin Wang, Peng Hu, Yimin Zhang, Yi Wang, Xu Pang, and Cao Tong Copyright © 2014 Qibin Wang et al. All rights reserved. Thermomechanical Fatigue Life Prediction for a Marine Diesel Engine Piston considering Ring Dynamics Sun, 19 Oct 2014 11:20:37 +0000 A newly designed marine diesel engine piston was modeled using a precise finite element analysis (FEA). The high cycle fatigue (HCF) safety factor prediction procedure designed in this study incorporated lubrication, thermal, and structure analysis. The piston ring dynamics calculation determined the predicted thickness of lubrication oil film. The film thickness influenced the calculated magnitude of the heat transfer coefficient (HTC) used in the thermal loads analysis. Moreover, the gas pressure of ring lands and ring grooves used in mechanical analysis is predicted based on the piston ring dynamics model. Tao He, Xiqun Lu, Dequan Zou, Yibin Guo, Wanyou Li, and Minli Huang Copyright © 2014 Tao He et al. All rights reserved. Experimental Investigation on Characteristics of Flow Instabilities in Centrifugal Pump Impeller under Part-Load Conditions Sun, 19 Oct 2014 08:21:33 +0000 This paper presents an experimental investigation of large-scale flow-field instabilities in a centrifugal pump impeller of low specific speed. Measurements of pump hydraulic performance and flow-field in the impeller passages were made with a hydraulic test rig and a Particle Image Velocimetry (PIV) system separately. Analyses of data and flow structures in the impeller passages were performed. Results showed that an unstable area existed in the range from 0.1 to 0.6 and had a close relationship with vortices in the impeller passages. With decreasing of flow rates, vortices experienced onset to expansion from 0.6 to 0.1 in visualization. was directly influenced by vortices between 0.1 and 0.6; and were significantly influenced by vortices from pressure side to the middle; however the slight impact was observed from the middle to suction side. Thus the experimental results could provide important evidence for the influence of flow instabilities on pump hydraulic performance. Denghao Wu, Yun Ren, Houlin Liu, Jiegang Mu, and Lanfang Jiang Copyright © 2014 Denghao Wu et al. All rights reserved. Improvement of Swirl Chamber Structure of Swirl-Chamber Diesel Engine Based on Flow Field Characteristics Thu, 16 Oct 2014 05:50:28 +0000 In order to improve combustion characteristic of swirl chamber diesel engine, a simulation model about a traditional cylindrical flat-bottom swirl chamber turbulent combustion diesel engine was established within the timeframe of the piston motion from the bottom dead centre (BDC) to the top dead centre (TDC) with the fluent dynamic mesh technique and flow field vector of gas in swirl chamber and cylinder; the pressure variation and temperature variation were obtained and a new type of swirl chamber structure was proposed. The results reveal that the piston will move from BDC; air in the cylinder is compressed into the swirl chamber by the piston to develop a swirl inside the chamber, with the ongoing of compression; the pressure and temperature are also rising gradually. Under this condition, the demand of diesel oil mixing and combusting will be better satisfied. Moreover, the new structure will no longer forma small fluid retention zone at the lower end outside the chamber and will be more beneficial to the mixing of fuel oil and air, which has presented a new idea and theoretical foundation for the design and optimization of swirl chamber structure and is thus of good significance of guiding in this regard. Wenhua Yuan, Yi Ma, Jun Fu, and Wei Chen Copyright © 2014 Wenhua Yuan et al. All rights reserved. Study on Optimizing Operation of Preheating Commissioning for Waxy Crude Oil Pipelines Wed, 15 Oct 2014 14:22:01 +0000 A mathematical model is established for the preheating commissioning process of waxy crude oil pipelines. The governing equations are solved by the finite volume method and the finite difference method. Accordingly, numerical computations are made for the Niger crude oil pipeline and the Daqing-Tieling 3rd pipeline. The computational results agree well with the field test data. On this basis, fluid temperature in the process of the preheating commissioning is studied for single station-to-station pipeline. By comparing different preheating modes, it is found that the effect of forward preheating is the best. Under different preheating commissioning conditions, the optimal combination of outlet temperature and flow rate is given. Jian Zhang, Yi Wang, Xinran Wang, Handu Dong, Jinping Huang, and Bo Yu Copyright © 2014 Jian Zhang et al. All rights reserved. Structure Design and Numerical Simulation of a High Performance Slit in Soft X-Ray Interference Lithography Beamline at SSRF Wed, 15 Oct 2014 06:43:58 +0000 A high precision slit in ultra-high vacuum is designed to develop a good performance soft X-ray interference lithography (XIL) beamline at Shanghai Synchrotron Radiation Facility (SSRF). In order to define the secondary source and enhance the performance of the beamline, many technical difficulties need resolving to design the precision slit. Therefore, to obtain reasonable design scheme, it is necessary to analyze the structural characteristics, the movement situation, the force state, the thermal load state, and the cooling state of the precision slit deeply by numerical simulation. The simulation results and the testing results demonstrate that the mechanical precision of the slit is at a high level and satisfies the requirements of the beamline. Xuepeng Gong, Qipeng Lu, and Zhongqi Peng Copyright © 2014 Xuepeng Gong et al. All rights reserved. Optimization of Process Parameters with Minimum Thrust Force and Torque in Drilling Operation Using Taguchi Method Tue, 14 Oct 2014 10:04:58 +0000 This research outlines the Taguchi optimization methodology, which is applied to optimize cutting parameters in drilling of AISI 1040 steel. The drilling parameters evaluated are cutting speed, feed rate, and helix angle. Series of experiments are conducted to relate the cutting parameters on the thrust force and torque. orthogonal array, signal-to-noise ratio is employed to analyze the influence of these parameters on thrust force and torque during drilling. Analysis of variance (ANOVA) is used to study the effect of process parameters on machining process. The study shows that the Taguchi method is suitable to solve the stated problem with the minimum number of trials. The main objective is to find the important factors and combination of factors that influence the machining process to achieve low thrust force and torque. The analysis of the Taguchi method indicates that the feed rate is the most significant factor affecting the thrust force, while the cutting speed contributes the most to the torque. Suleyman Neseli Copyright © 2014 Suleyman Neseli. All rights reserved. A Numerical Study of the Spring-Back Phenomenon in Bending with a Rebar Bending Machine Mon, 13 Oct 2014 09:04:16 +0000 Recently, the rebar bending methodology started to change from field processing to utilizing rebar bending machines at plant sites prior to transport to the construction locations. Computerized control of rebar plant bending machines provides more accurate and faster bending of rebars than the low quality inefficient field processing alternative. The bending process involves plastic deformation of rebars, where bending stress beyond the yield point of the material is applied. When the bending stress is removed, spring back is caused by the elastic restoring stress. Therefore, an accurate numerical analysis of the spring-back process is required to reduce the bending process errors. The most sensitive factors affecting the spring-back process are the bending radius, the bending angle, the diameter of the rebar, the friction coefficient, and the yielding strength of material. In this paper, we suggest a numerical modeling method using these factors. The finite element modeling of the dynamic mechanical behavior of the material during bending is performed using a commercial dynamic analysis program “DAFUL.” We use the least squares approach to derive the spring-back deflection as a function of the rebar bending parameters. Chang Hwan Choi, Lawrence Kulinsky, Joon Soo Jun, and Jin Ho Kim Copyright © 2014 Chang Hwan Choi et al. All rights reserved. A Model for Analyzing Temperature Profiles in Pipe Walls and Fluids Using Mathematical Experimentation Mon, 22 Sep 2014 08:59:40 +0000 Temperature profiling in both fluid and pipe walls had not been explained theoretically. The equations of energy balance and heat conductivity were queried by introducing known parameters to solve heat transfer using virtual mathematical experimentation. This was achieved by remodeling Poiseuille’s equation. Distribution of temperature profiles between pipe wall, fluid flow, and surrounding air was investigated and validated upon comparison with experimental results. A new dimensionless parameter (unified number (U)) was introduced with the aim of solving known errors of the Reynolds and Nusselts number. Moses E. Emetere Copyright © 2014 Moses E. Emetere. All rights reserved. Supersonic Shear Wave Imaging to Assess Arterial Nonlinear Behavior and Anisotropy: Proof of Principle via Ex Vivo Testing of the Horse Aorta Mon, 22 Sep 2014 05:26:08 +0000 Supersonic shear wave imaging (SSI) is a noninvasive, ultrasound-based technique to quantify the mechanical properties of bulk tissues by measuring the propagation speed of shear waves (SW) induced in the tissue with an ultrasound transducer. The technique has been successfully validated in liver and breast (tumor) diagnostics and is potentially useful for the assessment of the stiffness of arteries. However, SW propagation in arteries is subjected to different wave phenomena potentially affecting the measurement accuracy. Therefore, we assessed SSI in a less complex ex vivo setup, that is, a thick-walled and rectangular slab of an excised equine aorta. Dynamic uniaxial mechanical testing was performed during the SSI measurements, to dispose of a reference material assessment. An ultrasound probe was fixed in an angle position controller with respect to the tissue to investigate the effect of arterial anisotropy on SSI results. Results indicated that SSI was able to pick up stretch-induced stiffening of the aorta. SW velocities were significantly higher along the specimen’s circumferential direction than in the axial direction, consistent with the circumferential orientation of collagen fibers. Hence, we established a first step in studying SW propagation in anisotropic tissues to gain more insight into the feasibility of SSI-based measurements in arteries. D. A. Shcherbakova, C. Papadacci, A. Swillens, A. Caenen, S. De Bock, V. Saey, K. Chiers, M. Tanter, S. E. Greenwald, M. Pernot, and P. Segers Copyright © 2014 D. A. Shcherbakova et al. All rights reserved. Semiactive Self-Tuning Fuzzy Logic Control of Full Vehicle Model with MR Damper Sun, 21 Sep 2014 09:05:03 +0000 Intelligent controllers are studied for vibration reduction of a vehicle consisting in a semiactive suspension system with a magnetorheological (MR) damper. The vehicle is modeled with seven degrees of freedom as a full vehicle model. The semiactive suspension system consists of a linear spring and an MR damper. MR damper is modeled using Bouc-Wen hysteresis phenomenon and applied to a full vehicle model. Fuzzy Logic based controllers are designed to determine the MR damper voltage. Fuzzy Logic and Self-Tuning Fuzzy Logic controllers are applied to the semiactive suspension system. Results of the system are investigated by simulation studies in MATLAB-Simulink environment. The performance of the semiactive suspension system is analyzed with and without control. Simulation results showed that both Fuzzy Logic and Self-Tuning Fuzzy Logic controllers perform better compared to uncontrolled case. Furthermore, Self-Tuning Fuzzy Logic controller displayed a greater improvement in vibration reduction performance compared to Fuzzy Logic controller. Mahmut Paksoy, Rahmi Guclu, and Saban Cetin Copyright © 2014 Mahmut Paksoy et al. All rights reserved. Surface and Wear Analysis of Zinc Phosphate Coated Engine Oil Ring and Cylinder Liner Tested with Commercial Lubricant Thu, 18 Sep 2014 07:18:26 +0000 The objective of this study was to evaluate the tribological performance through investigating protective additive layer and friction coefficient and implementing the quantitative wear measurements on the rubbed surface of the sliding pairs. The specimens of oil ring were rubbed against cast iron engine cylinder liner under boundary lubrication conditions. The ring and liner surfaces were examined by optical, scanning electron microscope and atomic force microscopy. The elemental analysis of surfaces was performed by using energy dispersive X-ray spectroscopy. Surface observations showed that coating was removed from the ring surface. Higher levels of Ca, Zn, P, and S elemental ratios (0.93%, 0.45%, 1.55%, and 1.60% as atomic percent) were detected on the cylinder liner surface. Wear width, length, and depth measurements were performed by optical and atomic force microscopies on the ring and cylinder liner surface. The results showed that wear widths for oil ring were 1.59 μm and 1.65 μm; wear widths for cylinder liner were 3.20 μm and 3.18 μm; wear depths for oil ring were 100 nm; and wear depths for cylinder liner were 482 nm. Wear data were taken mostly from the additive layer points detected by SEM and X-ray measurements. Doğuş Özkan and Hakan Kaleli Copyright © 2014 Doğuş Özkan and Hakan Kaleli. All rights reserved. Analysis of the Influence of Microcellular Injection Molding on the Environmental Impact of an Industrial Component Wed, 17 Sep 2014 05:47:21 +0000 Microcellular injection molding is a process that offers numerous benefits due to the internal structure generated; thus, many applications are currently being developed in different fields, especially home appliances. In spite of the advantages, when changing the manufacturing process from conventional to microcellular injection molding, it is necessary to analyze its new mechanical properties and the environmental impact of the component. This paper presents a deep study of the environmental behavior of a manufactured component by both conventional and microcellular injection molding. Environmental impact will be evaluated performing a life cycle assessment. Functionality of the component will be also evaluated with samples obtained from manufactured components, to make sure that the mechanical requirements are fulfilled when using microcellular injection molding. For this purpose a special device has been developed to measure the flexural modulus. With a 16% weight reduction, the variation of flexural properties in the microcellular injected components is only 6.8%. Although the energy consumption of the microcellular injection process slightly increases, there is an overall reduction of the environmental burden of 14.9% in ReCiPe and 15% in carbon footprint. Therefore, MuCell technology can be considered as a green manufacturing technology for components working mainly under flexural load. Daniel Elduque, Isabel Clavería, Ángel Fernández, Carlos Javierre, Carmelo Pina, and Jorge Santolaria Copyright © 2014 Daniel Elduque et al. All rights reserved. Design and Analysis of a Split Deswirl Vane in a Two-Stage Refrigeration Centrifugal Compressor Sun, 14 Sep 2014 11:30:33 +0000 This study numerically investigated the influence of using the second row of a double-row deswirl vane as the inlet guide vane of the second stage on the performance of the first stage in a two-stage refrigeration centrifugal compressor. The working fluid was R134a, and the turbulence model was the Spalart-Allmaras model. The parameters discussed included the cutting position of the deswirl vane, the staggered angle of two rows of vane, and the rotation angle of the second row. The results showed that the performance of staggered angle 7.5° was better than that of 15° or 22.5°. When the staggered angle was 7.5°, the performance of cutting at 1/3 and 1/2 of the original deswirl vane length was slightly different from that of the original vane but obviously better than that of cutting at 2/3. When the staggered angle was 15°, the cutting position influenced the performance slightly. At a low flow rate prone to surge, when the second row at a staggered angle 7.5° cutting at the half of vane rotated 10°, the efficiency was reduced by only about 0.6%, and 10% of the swirl remained as the preswirl of the second stage, which is generally better than other designs. Jeng-Min Huang and Yue-Hann Tsai Copyright © 2014 Jeng-Min Huang and Yue-Hann Tsai. All rights reserved. Generation Planning Methodology Based on Load Factor for Hydroelectric Power Plants Thu, 11 Sep 2014 08:27:49 +0000 Major parameters affecting the generation capacity of hydroelectric plants are resource regime, reservoir geometry, and water head together with flow rate and efficiency. For the same resource regime and flow rate, water head can be altered depending on generation planning. By means of holding water in the reservoir and consequent increase in head can lead to boost power generation. In this paper, a method to compare two different operational styles has been identified; a plant operating with a low fixed head has been compared to a plant with an increased water head by means of holding water. In order to achieve this objective, an economical model including annual power revenues and net income increase depending on the operational strategy has been developed. Parameters affecting net income gain of the developed model are power generation boost and loss during peak and nonpeak durations, and electricity prices during peak and nonpeak durations. Depending on this model, strategies that would increase the plant revenue streams with increasing reservoir head have been presented in the results section of the paper. Süleyman Hakan Sevilgen and Hasan Hüseyin Erdem Copyright © 2014 Süleyman Hakan Sevilgen and Hasan Hüseyin Erdem. All rights reserved. Adaptive Algorithm for the Quality Control of Braided Sleeving Thu, 11 Sep 2014 07:05:04 +0000 We describe the development and application of a robot vision based adaptive algorithm for the quality control of the braided sleeving of high pressure hydraulic pipes. With our approach, we can successfully overcome the limitations, such as low reliability and repeatability of braided quality, which result from the visual observation of the braided pipe surface. The braids to be analyzed come in different dimensions, colors, and braiding densities with different types of errors to be detected, as presented in this paper. Therefore, our machine vision system, consisting of a mathematical algorithm for the automatic adaptation to different types of braids and dimensions of pipes, enables the accurate quality control of braided pipe sleevings and offers the potential to be used in the production of braiding lines of pipes. The principles of the measuring method and the required equipment are given in the paper, also containing the mathematical adaptive algorithm formulation. The paper describes the experiments conducted to verify the accuracy of the algorithm. The developed machine vision adaptive control system was successfully tested and is ready for the implementation in industrial applications, thus eliminating human subjectivity. Miha Pipan, Andrej Kos, and Niko Herakovic Copyright © 2014 Miha Pipan et al. All rights reserved. Ride Quality Assessment of Bus Suspension System through Modal Frequency Response Approach Thu, 11 Sep 2014 06:32:51 +0000 The ride dynamic characteristics of an urban bus were investigated through simulations with suspension component characteristics and were validated through field measurements. It was performed on highway road at a constant forward speed. A random vibration bus model with two parallel tracks of terrain profile was synthesized with superposition between the left and right sides as well as time delay between front and rear. The bus frequency response model was introduced with embedded modal extraction data to enhance computation efficiency. The simulation results of the bus model were derived in terms of acceleration PSD and frequency-weighted root mean square acceleration along the vertical axes at three locations, namely, driver side, middle, and rear passenger side, to obtain the overall bus ride performance. Another two sets of new leaf spring design were proposed as suspension parameter analysis. The simulation approach provides reasonably good results in evaluating passenger perception on ride and shows that the proposed new spring design can significantly improve the ride quality of the driver and passengers. Y. S. Kong, M. Z. Omar, L. B. Chua, and S. Abdullah Copyright © 2014 Y. S. Kong et al. All rights reserved. An Adaptive Vision-Based Method for Automated Inspection in Manufacturing Thu, 11 Sep 2014 05:50:36 +0000 This study proposes a new adaptive vision-based method combining discrete wavelet transform- (DWT-) based feature extraction and support vector machine (SVM) classification for automated inspection in manufacturing. This method involves transforming input optical images into a gray-level space and adaptively segmenting them by using region growing combined with DWT-based feature extraction based on support vector machines (SVMs). A multiclassifier SVM is first used to solve multicase problems in inspection. The SVM can be used to effectively classify samples based on the segmented images combined with the image features and perform superior multiclass classification. The proposed algorithm can select the most suitable features for the inspection from many features. The method achieves high-performance inspections and produces more favorable results than existing methods do. Tsun-Kuo Lin Copyright © 2014 Tsun-Kuo Lin. All rights reserved. Influence of Compression Ratio on the Performance and Emission Characteristics of Annona Methyl Ester Operated DI Diesel Engine Thu, 11 Sep 2014 00:00:00 +0000 This study aims to find the optimum performance and emission characteristics of single cylinder variable compression ratio (VCR) engine with different blends of Annona methyl ester (AME) as fuel. The performance parameters such as specific fuel consumption (SFC), brake thermal efficiency (BTE), and emission levels of HC, CO, Smoke, and NOx were compared with the diesel fuel. It is found that, at compression ratio of 17 : 1 for A20 blended fuel (20% AME + 80% Diesel) shows better performance and lower emission level which is very close to neat diesel fuel. The engine was operated with different values of compression ratio (15, 16, and 17) to find out best possible combination for operating engine with blends of AME. It is also found that the increase of compression ratio increases the BTE and reduces SFC and has lower emission without any engine in design modifications. Senthil Ramalingam, Paramasivam Chinnaia, and Silambarasan Rajendran Copyright © 2014 Senthil Ramalingam et al. All rights reserved. Vehicle Impact Analysis of Flexible Barriers Supported by Different Shaped Posts in Sloping Ground Thu, 11 Sep 2014 00:00:00 +0000 A roadside guardrail may be constructed near slopes. The desired safety behavior is ensured not only by the guardrail structure itself, but also by the interaction between soil and guardrail post. In the case of horizontal ground, the elastic Winkler spring model and the - curve approach can be used to estimate the soil-post interaction by the finite element method. However, it is difficult to apply those models with the sloping ground cases unless sufficient experimental data are given through the single post impact tests. This paper evaluates, using LS-DYNA software, the vehicle impact performance of flexible barriers made of steel W-Beam guardrails in sloping ground that are also supported over three different types of post configurations. The dynamic performance is tested in terms of maximum deflection, absorbing impact energy, and occupant risk index according to post types. Dong W. Lee, Jae S. Ahn, and Kwang S. Woo Copyright © 2014 Dong W. Lee et al. All rights reserved. Optimal Process Conditions for the Manufacture of Aluminum Alloy Bicycle Pedals Wed, 10 Sep 2014 00:00:00 +0000 Numerous forms and manufacturing methods of bicycle pedals exist in current markets. The purpose of this study was primarily to design an innovative forging die for a bicycle pedal company through a simulative analysis, using commercial finite element package software. A series of simulation analyses adopted workpiece temperature, mold temperature, forging speed, friction factor, and size of the mold as variables to evaluate the methods of lightweight in the bicycle pedal forging press. The study involved modifying professional bicycle pedal sizes. The effective strain, effective stress, and die radius load distribution of the pedals were analyzed under various forging conditions. Aluminum (A6061 and A7075) was used to analyze the simulative data. The optimal control parameters were subsequently obtained using the Taguchi methods and a genetic algorithm. The results of the simulation analyses indicated that the design of an experimental forging die can lower the deformation behavior of a bicycle pedal. Dyi-Cheng Chen, Jheng-Guang Lin, Wen-Hsuan Ku, and Jiun-Ru Shiu Copyright © 2014 Dyi-Cheng Chen et al. All rights reserved. A Comparison of a Standard Genetic Algorithm with a Hybrid Genetic Algorithm Applied to Cell Formation Problem Sun, 07 Sep 2014 11:00:17 +0000 Though there are a number of benefits associated with cellular manufacturing systems, its implementation (identification of part families and corresponding machine groups) for real life problems is still a challenging task. To handle the complexity of optimizing multiple objectives and larger size of the problem, most of the researchers in the past two decades or so have focused on developing genetic algorithm (GA) based techniques. Recently this trend has shifted from standard GA to hybrid GA (HGA) based approaches in the quest for greater effectiveness as far as convergence on to the optimum solution is concerned. In order to prove the point, that HGAs possess better convergence abilities than standard GAs, a methodology, initially based on standard GA and later on hybridized with a local search heuristic (LSH), has been developed during this research. Computational experience shows that HGA maintains its accuracy level with increase in problem size, whereas standard GA looses its effectiveness as the problem size grows. Waqas Javaid, Adnan Tariq, and Iftikhar Hussain Copyright © 2014 Waqas Javaid et al. All rights reserved. Numerical Computation and Optimization of Turbine Blade Film Cooling Thu, 04 Sep 2014 00:00:00 +0000 The effect of film cooling parameters on the cooling effectiveness of an actual turbine blade is studied numerically. Film cooling parameters such as the hole shape, holes distribution, blowing ratio, streamwise angle, and spanwise angle are investigated to select the appropriate cooling parameters. Unstructured finite volume technique is used to solve the steady, three-dimensional, and compressible Navier-Stokes equations. Using one cooling holes array indicates that the average overall film cooling effectiveness is enhanced by decreasing the streamwise angle for high blowing ratio on the suction side of the turbine blade. The film cooling effectiveness is enhanced on the pressure side for a blowing ratio of unity. In addition, the cooling effectiveness increases by increasing the lateral and forward diffusion angles. The computations reveal that the efficiency of cooling is decreased at the leading edge due to the large surface curvature of the blade. The presence of compound shape (spanwise angle) enhanced the film cooling effectiveness on the two sides. Multistagger cooling hole arrays are investigated and the results indicate that five-stagger cooling arrays on the pressure side and three-stagger cooling arrays on the suction side with LFDCA-9.3-14.6 hole shape are enough to have good cooling of the two sides using 2.17% bleed air of the engine. Ahmed M. Elsayed, Farouk M. Owis, and M. Madbouli Abdel Rahman Copyright © 2014 Ahmed M. Elsayed et al. All rights reserved.