bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis, Design and Implementation of DC-DC Boost Converter Using H∞ Loop Shaping Controller
Authors: Tamilarasi Devaraj , Namith A. Abdul , Sivakumaran T.S.
Published: August 2014

This paper proposes the H∞ loop shaping control scheme for DC-DC boost converter using Pulse-width modulation (PWM) techniques. The averaged linear model of the boost converter is developed for three controllers namely classical control (voltage mode), post modern control (H∞ control) and H∞ loop shaping using Ricatti equations which guarantee stability and the desired closed loop dynamic response. The experimental results are accomplished using DSP TMS320LF2407 validated with simulation results that shows the proposed H∞ loop shaping controller has better performances with good tracking and high rejection capability when disturbances are introduced due to changes of load and input voltage.
Multilevel Inverter for Hybrid Energy Generation System
Authors: Karthikeyan Vasudevan , Jamuna Venkatesan , James Abisha
Published: August 2014

Applications of multilevel inverters have been widely accepted for high-power and high-voltage industry purposes. Their performance is very much superior to that of traditional two-level inverters due to reduced harmonic distortion and lower electromagnetic interference. In this paper a multilevel inverter circuit with reduced number of switches and symmetric voltage sources has been designed for hybrid generation system. The switching angles for various levels of the output are obtained by using the simple sine property. Finally, the 11-level inverter model is built using Matlab/ Simulink to validate this topology. The simulation results are presented.
Power Quality Problems in PV Fed Grid Connected Inverter
Authors: Saritha Natesan , Jamuna Venkatesan , Nanthini N.
Published: August 2014

—– In this paper, problem faced by grid connected pv inverter is presented. Inverters connected to grid are mostly affected due to short circuit problems in the power systems. Therefore it is essential to analyze power quality disturbances in order to improve the quality of the system. Performance of inverter is affected severely by voltage sag compared to other type of power quality disturbances. Also in this paper, multilevel inverter with sag condition and without sag condition is simulated using MATLAB/SIMULINK software
Suitability of Asymmetrical Multilevel Inverters for Partial Shaded Photovoltaic Systems
Authors: Malathy S. , Ramaprabha R.
Published: August 2014

The efficiency of building integrated photovoltaic (PV) system is greatly affected by the partial shaded conditions. The impact of shading conditions depends not only on the level of shading but also on other factors like array size, type of configuration adopted, pattern and intensity of the shade. The influence of partial shading is much pronounced in series configuration than any other types due to the absence of cross ties. Unless protected by bypass diodes, the thermal stress across the panel increases under shaded conditions and eventually leads to the development of hot spots that can damage the shaded panel permanently. Bypass diode totally isolates the shaded panel from the rest of the of the array leaving the array underutilized. To address this issue, this paper proposes repositioning of the panels to distribute the shade uniformly all over the array. Besides, a hybrid asymmetric multilevel inverter is proposed for power conversion.
Three Phase Matrix Converter for Variable Speed Wind Energy System
Authors: Jamna Ayadathil , Jamuna Venkatesan , Sathy Rama Reddy
Published: August 2014

In this paper, a direct ac-ac converter suitable for a variable speed wind energy conversion system is proposed. In wind energy conversion systems, due to the variation in wind speed, there will be variation in shaft speed and hence the frequency of the output will be fluctuating at the generator terminal. A direct ac-ac converter (Matrix converter) is capable of providing simultaneous control of output voltage and frequency at the generator output. In this paper the direct transfer function method is developed, to create a constant voltage and constant frequency output from a variable output voltage and frequency and the same is simulated using MATLAB/SIMULINK simulation software.
Z - Source Inverter for Drive Applications
Authors: Sasikala Shanmugam , Jamuna V.
Published: August 2014

This paper deals with “Z – source inverter for drive applications”, which provides a better solution for the drive in an industrial application by providing higher voltage buck/boost ability with effective and efficient use of supply with easy achievement of controllability at low cost using Z – Source inverter. The hardware implemented by a PIC microcontroller draws parallel operational parameters to provide the required speed and frequency. Thus PIC16F477A proves to be a potential response as a controller for Z – Source inverter and drive.
Design and Simulation of Self Lift Positive Output Luo Converter Using Incremental Conductance Algorithm for Photovoltaic Applications
Authors: Chilambarasan M. , Devi M. Latha , Babu M. Ramesh
Published: August 2014

This paper presents the design and simulation of self-lift positive output P/O luo converter using Incremental Conductance (IncCond) algorithm for photovoltaic applications. The solar panel model is developed using the basic circuit equations of photovoltaic cell. The MPP of a solar panel varies with irradiation and temperature. The IncCond algorithm is used to track the maximum power from the solar panel. The unregulated voltage from the panel will be regulated by using the self-lift luo converter. It will reduce the voltage and current ripple. As for component stress, the self-lift luo converter has a smaller voltage and current stresses than the original luo converter. Matlab/Simulink is used for simulation studies.
Ductility of Concrete Encased Cold-Formed Steel Beam with Trapezoidally Corrugated Web
Authors: Divahar Ravi , Joanna Philip Saratha
Published: August 2014

Engineers have realized that corrugated webs enormously increase their load carrying capacity as well as stability against buckling and can result in very economical design. In this paper, the results of the experiments conducted on cold-formed steel beam with encased trapezoidally corrugated webs with a view to study their strength and ductility are presented. The ductility of cold-formed steel beam with plain web and corrugated web is compared with that of encased trapezoidally corrugated web. Data presented include the load versus deflection curves, load versus strain curves, strength capacity, displacement ductility indices and moment versus curvature curves. It is found that the beam with encased trapezoidally web not only increases the moment carrying capacity but also the ductility. The results showed that the Super elastic property of encased corrugated web beams enhances the usage of it in the earthquake resistant structures.
Security Method for Multimedia Content by Using Watermarking
Authors: Kavitha R. , Arivuselvam B. , Anand G.
Published: August 2014

Digital watermarking is a technique developed to help copyright protection of Image, audio & video files. It has been spurred by the growth of the Internet, and the ease of copying. This has led to an unprecedented numbers in copyright infringements. The digital audio & video watermarking is concerned with embedding data in a signal the watermark data can be accurately detected. Watermarking algorithm based on Empirical Mode Decomposition (EMD) is introduced. The signal is divided into frames and each one is decomposed adaptively by Empirical Mode Decomposition into intrinsic oscillatory components. The data embedding rate of EMD algorithm is 46.9-50.3 b/s; the robustness of hidden watermark is identified using Mp3 compression, additive noise, and quantization, cropping, filtering and resampling.
Harmonic Reduction in Grid Connected Wind Energy System with Dynamic Voltage Restorer Using Fuzzy Logic Technique
Authors: Kumar B. Ashok , Kamaraj N. , Subasri C.K.
Published: August 2014

Grid connected Wind energy conversion system uses power Electronic converters hardly in fixed speed systems except for reactive power compensation. This Power Electronic converter causes major electrical losses and affects power quality of the system. The quality of the voltage and current is also affected by sensitive loads which are used widely in most of Automated Industries and Research laboratories. Disturbances in waveforms occurs which results in harmonics. To improve such power quality problem of the system DVR which is based on fuzzy logic technique is introduced. The system is tested for conventional technique and also with fuzzy logic. The performance is investigated through MATLAB/SIMULINK software. The simulation results confirm the superior performance of the proposed DVR based fuzzy logic technique than conventional technique. The proposed system reduces harmonics as well as mitigates voltage sag/swell.
Reactive Power Pricing by Power Flow Tracing Method
Authors: Mahesh V. , Kamaraj N.
Published: August 2014

Power flow tracing based reactive power pricing scheme is presented in this paper. A method is suggested to solve the problem of bidirectional flow of reactive power. The reactive power allocated by each generator to all the load buses is found and the corresponding cost to be paid by the load to generator is calculated. Super position principle based method is used to calculate the allocation of reactive power by the generators to the loads. Costs allocated for generators are found using quadratic cost function. The method is implemented on IEEE standard bus system and the results are found satisfactory.
Relieving Transmission Congestion by Optimal Rescheduling of Generators Using PSO
Authors: Muthulakshmi K. , Babulal C.K.
Published: August 2014

Congestion management is one of the most important issues for secure and reliable system operations. One of the most practiced techniques for congestion management is rescheduling the real power output of generators in the system. In this paper Particle Swarm Optimization (PSO) is used to determine the optimal generation levels to alleviate transmission congestion. Numerical results on IEEE 30 Bus test system is presented and the experimental outcomes demonstrate that PSO is one among the demanding optimization methods which are certainly capable of obtaining higher quality solutions for the proposed problem.
Online Condition Monitoring and Torque Control of VSI Fed PMSM Drive
Authors: Devipriya D. , Malhija Jerlina P. , Beno M. Marseline
Published: August 2014

Permanent magnet synchronous motor is employed in wide applications because of its high power density. However, due to the continuous running of the motor the rotor temperature will get increased and hence the rotor flux linkage will be reduced. So the parameters like rotor flux linkage, torque and voltage distortion has to be estimated in order to increase the performance of the drive. Fuzzy logic controller is used for the control of torque. Fuzzy logic controller employed here mainly to reduce the ripple present in the torque waveform and also to increase the static and dynamic performance of the system. In order to find the temperature of the motor a pair of thermocouple is placed on the either sides of the stator. The main aim of the proposed project is to improve the performance and efficiency of the drive with the controlled ripple free torque.
Compression Techniques for Medical Images Using SPIHT
Authors: Perumal B. , Rajasekaran M. Pallikonda
Published: August 2014

Medical imaging is important in trendy medical aid that gives diagnostic info for clinical management of patients and designing of treatment. Every year, terabytes of medical image data’s square measure used through advanced imaging modalities like Positron Emission Tomography (PET) Magnetic Resonance Imaging (MRI), Computed Tomography (CT), and lots of additional new methodology of medical imaging. Advances in technology have created the chance for radiology systems to use complicated compression algorithms to scale back the file size of every image in an attempt to partly offset the rise in knowledge volume created by new or additional complicated modalities whereas protective the numerous diagnostic info. This paper outlines the various compression strategies like Discrete Cosine Transform (DCT), Fractal Compression and Set Partitioning In hierarchical Trees (SPIHT) applied to numerous medical pictures. Experimental results show that the projected SPIHT approach achieves the next Compression Ratio (CR), Bits Per Pixel (BPP) and Peak Signal to Noise Ratio (PSNR) with less Mean square Error (MSE) in comparison with DCT methodology.
Compressive and Shearing Mechanical Anisotropy of Aluminum after ECAP
Authors: de Faria Cleber Granato , Pedrosa Tércio Assunção , Figueiredo Roberto B. , Aguilar Maria Teresa Paulino , Cetlin Paulo Roberto
Published: August 2014

Severe plastic deformation (SPD), where metals are deformed up to very high strain values, leads to a very small grain size and a high strength of the material. ECAP (Equal Channel Angular Pressing) is one of the SPD methods, and involves the extrusion of a metal billet through two intersecting channels with identical cross-section and forming an angle between them. The material undergoes shearing as it crosses from one channel to the other, but its external dimensions are not altered. Shearing occurs along a single plane, which may lead to anisotropy in the mechanical properties of the material after ECAP. Compression, tension and shearing tests along various directions in the as-processed specimens indicated the presence of mechanical anisotropy in ECAP processed aluminum.
Mechanical Characteristic Changes of Carbon Fiber Reinforced Plastics (CFRP) Depending on the Lamination Methods
Authors: Cha In Pyo , Shin Hee Jae , Lee Min Sang , Hong Sung Woo , Kwon Jin Young , Ko Sun Ho , Kim Hong Gun , Kwac Lee Ku
Published: August 2014

The prepreg process among the CFRP (Carbon Fiber Reinforced Plastic) forming methods is the short term of ‘Pre-impregnation’, which is widely used for aerospace composites that require a high quality property such as a fiber-reinforced woven fabric, in which an epoxy hardening resin is impregnated. the reality is, however, that this process requires continuous researches and developments for its commercialization because the delamination characteristically develops between the layers when a great weight is loaded from outside. to supplement such demerit, three lamination methods among the prepreg lamination methods of CFRP were designed to minimize the delamination between the layers due to external impacts. Further, the newly designed methods and the existing lamination methods were analyzed through a mechanical characteristic test, tensile test and infrared thermal device during the tensile tests, to obtain a better property than the existing lamination methods. the tensile test result showed that the newly designed three lamination methods, i.e. Roll, Half and Zigzag lamination methods, appeared superior to the Play lamination method in the aspects of the strength and strain. The strength of the Zigzag lamination method, which was the highest, was confirmed as being improved by about 20% than that of the Ply method.
Effects of Number of Inserts and Insert Materials on Surface Roughness of Cast-Iron Work Produced by Face Milling
Authors: Siwawut Sutham , Saikaew Charnnarong , Wisitsoraat Anurat
Published: August 2014

In this work, the effects of two key factors of face milling including the number of inserts and insert material on surface roughness of cast-iron turbine housing work were systematically studied using full factorial designed experiments. Three insert materials including uncoated cemented carbide (TH10), commercial TiAlN/TiN coated cemented carbide (AH120) and tungsten carbo-nitride (WCN) coated cemented carbide were selected while the number of inserts was varied from 1 to 3 in this study. The results showed that both factors were statistically significant and the optimal parameters that yielded minimum Ra-value of 0.495 μm were the commercial TiAlN/TiN coated cemented carbide material (AH120) and three inserts.
Numerical Simulation of Compressive Response of Open-Cell Aluminum Foams
Authors: Machado Margarida , Peixinho Nuno
Published: August 2014

The compressive properties of open-cell aluminum foams are numerically studied using representative volume elements by means of the finite element method. Four face body centered cubic cell arrangements are analyzed, namely uniform-size with spherical pores and dual-size with spherical pores. The results demonstrated that a cell configuration with dual-size pore arrangement presents improved properties for applications subjected to compression loading. This is attributed to the introduction of secondary pores in the cell structure that provide an increase in the specific stiffness and strength of open-cell aluminum foams.
Effect of Powder Flow Rate and Gas Flow Rate on the Evolving Properties of Deposited Ti6Al4V/Cu Composites
Authors: Erinosho Mutiu F. , Akinlabi Esther Titilayo , Pityana Sisa
Published: August 2014

—Pure copper was deposited with Ti6Al4V alloy via laser metal deposition (LMD) process to produce Ti6Al4V/Cu composites. This paper reports the effect of powder flow rate (PFR) and gas flow rate (GFR) of laser metal deposited Ti6Al4V/Cu composites. The deposited samples were characterised through the evolving microstructure and microhardness. It was observed that the PFR and GFR have an influence on the percentage of porosity present in the samples. The higher the flow rates of the powder and the gas, the higher the degree of porosity and vice versa. The widmanstettan structures were observed to be finer as the flow rate reduces which in turn causes a decrease in the hardness values of the deposited composites. The hardness values varied between HV381.3 ± 60 and HV447.3 ± 49.
Vibration Analysis of Four-Edge Clamped Plain Weave Composite Plates with Different Impact Damage Patterns: An Experimental Study
Authors: Yetmez Mehmet , Erdogan Hamza , Kocer Levent , Demirci Ismail
Published: August 2014

In this study, dynamic analysis of carbon plain weave square plates with different damage patterns including pattern of post-low velocity impact and patterns of post-ballistic impact is considered. For this purpose, vibration tests are performed to present the vibration characteristics of the four-edge clamped square plates. Effects of bullet-tip geometry, projectile velocity and impact damage location on the vibration characteristics are examined experimentally. Results are given in graphical form.
Static and Dynamic Tensile Behavior of Unidirectional Glass/Epoxy Composites
Authors: Correia Pedro , Peixinho Nuno
Published: August 2014

A widespread application of composite materials requires proper knowledge of both static and dynamic loading properties, particularly for automotive and transportation applications. In this study the behavior of unidirectional glass fiber reinforced polymeric composites under uniaxial loading is determined at quasi-static and intermediate strain rates in the range 0.6–500/s. The tensile tests were performed using different servo-hydraulic testing apparatus. Dynamic tests results are compared with the results of static tensile tests carried out on specimens with identical geometry. Experimental results show a significant increase of the tensile strength with increasing strain rate. The strain to failure is also observed to increase slightly for higher strain rates.
Parametric Aircraft Design Optimisation Study Using Span and Mean Chord as Main Design Drivers
Authors: Albuquerque Pedro , Gamboa Pedro , Silvestre Miguel
Published: August 2014

The present work describes an aircraft design methodology that uses the wingspan and its mean aerodynamic chord as main design parameters. In the implemented tool, low fidelity models have been developed for the aerodynamics, stability, propulsion, weight, balance and flight performance. A Fortran® routine that calculates the aircraft performance for the user defined mission and vehicle’s performance requirements has been developed. In order to demonstrate this methodology, the results for a case study using the design specifications of the Air Cargo Challenge 2013 are shown.
Wind Tunnel Study on a Missile with Forward-Facing Cavity in Supersonic Flow
Authors: Zhang Jiang , Pan Xiao Jun , Dong Jin Gang , Qin Yong Ming , Ma Han Dong
Published: August 2014

A forward-facing cavity will be composed of the components of a scramjet from inlet to combustion chamber which has a uncovered inlet before the separation of the booster. Longitudinal oscillations are generated within the cavity under some certain flow conditions. Strong oscillations may damage the components of the scramjet, or induce bow-shock oscillations which may cause unsteady loads on the missile and affect the performance of the aerodynamical characteristics. An experimental study of missile model with a scramjet was conducted in a transonic wind tunnel. The characteristics of cavity flow were researched by both the dynamic force measurement and the fluctuation pressure measurement. In the experiments the oscillations within the cavity and the bow-shock in front of the inlet interacted. The oscillations of cavity flow and bow-shock affected the fluctuation pressure and the aerodynamical characteristics of missile remarkably. The amplitude of axial force was higher than the normal force's. The RMS of the fluctuation pressure of some measured place inside the scramjet reached a quarter of the total pressure, and the amplitude of the fluctuation reached half of the total pressure. Those might threaten the safety of the structure of the scramjet.
A SMA Based Morphing Leading Edge Architecture
Authors: Ameduri Salvatore
Published: August 2014

This paper analyses a morphing leading edge device, activated by a Shape Memory Alloy (SMA) actuator. The objective is to achieve the Droop Nose effect for particular phases of the flight (e.g. take-off, landing), both obtaining an increased lift and preserving the laminar flow. The device is constituted of: a kinematic chain at the level of the wing section, transmitting motion to the skin, this way fitting the Droop Nose target shape; a span-wise architecture integrated with a SMA actuator, ensuring both a reduction of the actuation forces and the balancing of the aerodynamic external load. A dedicated logical framework was adopted for the design, taking into account the SMA material features and the device intrinsic non-linearity. The framework was integrated within an optimization genetic algorithm, to fit the target shape with an appropriate architecture topology. The optimized system proved to produce the desired morphing, also under the most severe aerodynamic loads.
Vacuum Degree Measuring Technique and its Development Tendency inside a Satellite in the Thermal Vacuum Test
Authors: Xu Zhong Xu , Wu Yue , Du Chun Lin
Published: August 2014

In order to avoid vacuum discharge, it is necessary for the satellite to have real-time monitoring by the vacuum degree of the electrical components that are sensitive to vacuum degree in the process of the thermal vacuum test. This paper introduces two methods of measuring vacuum degree inside the satellite, makes an analysis of failure mechanism of ionization gauge method, and offers suggestions for improvement.
Application of Rare Event Anticipation Techniques to Aircraft Health Management
Authors: Alestra Stephane , Bordry Cristophe , Brand Cristophe , Burnaev Evgeny , Erofeev Pavel , Papanov Artem , Silveira-Freixo Cassiano
Published: August 2014

Generally faults in complex technical systems (such as aircrafts) can be considered as rare events. In this paper we apply classification techniques to problem of rare events anticipation and demon-strate the approach to predictive maintenance of aircrafts through the real-world test cases from aircraft operations based on the data granted by AIRBUS.
SOA-Cloud Computing Based Fast and Scalable Simulation Architecture for Advanced Flight Management System
Authors: Li Da Chuan , Li Qing , Cheng Nong , Song Jing Yan
Published: August 2014

This paper presents a SOA and cloud computing based architecture for the distributed simulation of advanced flight management system (FMS). The architecture is designed to facilitate the fast simulation, validation and evaluation of different FMS system designs and functionalities with customized system configurations and widely varying aircraft equipage levels under various operation conditions. It is also intended to accommodate the potential evolutionary extensions of new avionics concepts and functionalities such as the future CNS/ATM and 4-D trajectory based technologies. To address the requirements of flexibility, scalability and reusability, the design of the simulation architecture takes advantage of the cloud computing and service oriented architecture (SOA) and the key enabling technologies are developed: simulation unit service encapsulation, simulation agent technology and simulation orchestration. Based on the proposed architecture associated technologies, the simulation components are encapsulated as services or accessed through agents, and the configuration of different FMS system frameworks and simulation tasks can be achieved through simulation orchestration. A prototype avionic simulation system that implements the SOA/cloud computing architecture is developed and illustrated with application cases. The applications demonstrate that the proposed architecture enables fast and scalable simulation of both existing and new FMS design and technologies.
Using Low Temperature Irradiation for ELDRS Estimation
Authors: Pershenkov V.S. , Bakerenkov A.S. , Yastrebov A.T. , Solomatin A.V. , Belyakov V.V. , Shurenkov V.V.
Published: August 2014

The technique for low dose rate response prediction, based on the combination of low, room and elevated temperature irradiation was described. The possibility of using Test Method 1019.8 for space applications was considered.
Analysis of an Airdrop Motion Coupling N-S Equations with 6 DOF Motion Equations
Authors: Hu Ping , Wang Li Xin , Guo Liang Min
Published: August 2014

An airdrop model with aerial carrier is carried out to simulate an airdrop test. A coupled CFD/6 DOF is designed to compute the orientation and trajectory of the airdrop model. The results show that the CFD/6 DOF coupled method is appropriate to simulate this problem with a sufficient precision. The airdrop’s motion is strongly coupled with the aerodynamic force after leaving the sliding rail and the trajectory of its CG is mainly in the symmetry of the aerial carrier. The variation of its orientation mainly rolls in X axis direction and it swings as an approximate periodic oscillation which amplitude decreases over time. The maximum angle of orientation in X axis direction is-116°in 5 seconds. The similar variation of the airdrop motion is present in different angle of attack and sideslip of the aerial carrier.
Analysis of an Aero-Engine Gas Path Fault Monitoring Sensor Model
Authors: Qu Jian Feng , Jiang Shi Qi , Yuan Shi Hui , Zeng Su Fan
Published: August 2014

A new aero-engine gas path fault monitoring technology is presented in this paper, which is based on the capacitive sensor. The working conditions of the aero-engine gas path components can be monitored through the sensor, which is the main source of the aero-engine faults such as the gas path debris. The capacitive sensor has advantages of non-contact measurement, high sensitivity and simple structure, which can effectively solve the problems of the traditional aero-engine gas path fault diagnosis technology, such as the poor operability, the weak real-time performance and the high cost. Through the analysis of the capacitive sensor model, the feasibility of the capacitive sensor in the aero-engine gas path fault monitoring is verified.
Study of a W-Beam Guardrail Behaviour in Road Safety Barriers
Authors: Peixinho Nuno , Tavares João , Meireles José
Published: August 2014

This study presents results regarding a numerical simulation of the plastic displacement of a road guardrail. An experimental study of two different guardrails was conducted in order to collect information regarding displacement due to a determined force behavior. These tests were then simulated in Ansys Workbench to recreate the elastic and plastic domain of the material. The guardrails are two meters long, supported by two simple cylinders while being pressed at the center by a third one. In order to explore the software two different mesh sizes were used to compare their efficiency, being concluded with the comparison between the force-displacement curves of numerical and experimental results.
Numerical Studies of Engine Performance, Emission and Combustion Characteristics of a Diesel Engine Fuelled with Hydrogen Blends
Authors: Ozgur Tayfun , Tosun Erdi , Ozgur Ceyla , Tuccar Gökhan , Aydın Kadir
Published: August 2014

In this study the performance, exhaust emission characteristics and combustion process of the engine fueled with hydrogen-diesel blends were compared to diesel fuel. Hydrogen was blended with diesel fuel at the volumetric ratios of 5%, 10% and 20%. AVL BOOST software was dedicated to simulate the performance and emission values for various blends of hydrogen with diesel fuel. The simulation results showed that hydrogen addition to diesel fuel improve both engine performance and exhaust emmisions.
Investigation of Effects Ofinlet Boundary Conditions on the Flow Behaviour in a Diesel Injector
Authors: Tuccar Gökhan , Ozgur Tayfun , Tosun Erdi , Ozgur Ceyla , Aydin Kadi̇r
Published: August 2014

Diesel engines become popular from this point of view because of their high thermal efficiency. However, new and developing technologies are expected to lower their emission levels. Atomization of the fuel has a vital importance in order to control heat release rate and exhaust emission during combustion. With the known injection devices, atomization of the fuel is realized with high pressure systems such as common rail direct injectors (CRD) which operate at pressures exceeding 1300 bar. However, atomization of the fuel by simply increasing injection pressure can create cavitation erosion which may lead to mechanical failure of the nozzle. Utilization of air in diesel engine injectors will increase fuel atomization, provides more complete combustion of any diesel fuel consumed, enhance fuel economy and results in lower engine emissions. Therefore the aim of this study is to design a special injection device for use in a diesel engine which improves combustion by mixing air and fuel inside itself at optimum ratio. Proper air inlet pressure was determined for favorable diesel air mixing by investigation of the flow behavior in a newly designed injection device with the help of computational fluid dynamics based software. Three different air inlet pressures (20, 30 and 40 bar) are simulated and the contours of turbulence intensity, velocity and volume fraction of diesel fuel are discussed, and compared with each other.
Modeling and Analysis on Mean Effective Torque of Rotors in Twin-Rotor Cylinder-Embedded Piston Engine
Authors: Chen Hu , Pan Cun Yun , Xu Xiao Jun , Zhang Xiang , Xu Hai Jun
Published: August 2014

Torque, as an important indicator of the engine, is the reflection of performance of cylinder-embedded piston engine. In power stroke, torque varies at different moments, so if the impact of structural parameters on torque needs to be analyzed, the values of torque in power stroke need to be added together and divide lasting time. The average effective torque is the average of the torque generated by explosive force during the entire power stroke, which overcomes the disadvantages of the instantaneous torque which can not reflect the changes in power process. Therefore, the influence of each structure size on the force transmission performance can be analyzed with maximizing the average effective torque. It is concluded that for increasing the average effective torque, the radius of the hinge center trajectory of cap R should be increased, and the length from rotating center O to the trajectory of piston H should be decreased. The length of rod L has little influence on the average effective torque. However, if there is a too large D-value between R and H, the rod may deflect seriously, so that the piston side force increases, causing the piston wear and tear. So the values of R and H should be selected with specified conditions in the design.
The Simulation of Rotor Field Oriented Control of PMSM
Authors: Ou Feng , Chen Hong , Chen Ying
Published: August 2014

Permanent magnet synchronous motor (PMSM) has been widely in production and everyday life, and its control system has been a difficult point needing more researches. Therefore, it is important to investigate the control system of PMSM. In order to ensure the dynamic and static performance of PMSM, this paper presents a new vector control method based on the rotor field oriented control (RFOC) technology. The paper introduces the fundamental principal of RFOC, and designs three loop servo control simulation system and analyses the result of the simulation. The results shows that the RFOC system has high dynamic and static performance by adopting the three loop control. And the analysis can also provide a reference for similar servo control system design personnel.
A Novel Approach to Model and Implement Planar Trajectory-Tracking Controllers for AUVs/ASVs
Authors: Dong N. , Nam N.H. , Tuan K.M. , Hien N.V.
Published: August 2014

Following the Model-Driven Architecture (MDA) approach, we have modeled and implemented a planar trajectory planning and tracking controller designed for Autonomous Underwater Vehicles or Autonomous Surface Vessels (AUVs/ASVs). Our approach covers steps such as the requirement, analysis, design and implementation to model and realize a controller for most standard AUV/ASV platforms. It also allows the designed elements to be customizable and re-usable in the development of new applications of AUV/ASV controllers. The paper describes step-by-step the development lifecycle of planar trajectory-tracking controller for AUVs/ASVs. Based on this approach, a horizontal trajectory-tracking controller of a miniature autonomous submerged vehicle is completely developed and successfully taken on trial trip.
Robotic Vision for Hospital Inspection
Authors: Jamaludin Syukrul Hassani , Mansor Muhammad Naufal , Junoh Ahmad Kadri , Ahmed Amran , Daud Wan Suhana Wan , Idris Azrini
Published: August 2014

Observation system is implementing an automatic visual for observation that has recently got a considerable interest to researchers. Nowadays, technology has reached a stage where mounting video camera is cheap and friendly-user tools causing a widespread usage of cameras in public or private areas. Finding available human resources to sit and watch the imagery is too expensive for most organizations to afford the cost of human operators. Moreover, observation process by operators is error prone due to fatigue, negligence and lack of ubiquitous surveillance. Therefore, it is important to develop an accurate and efficient automatic video analysis system for monitoring patient activity that will create good opportunities by saving the cost of human resource employment because vision system can perform observation process for 24 hours per day. The system will allow us to detect unusual events in the scene and warrant the attention of whomever in charge to take preventive actions. The purpose of visual observation is not to replace human eyes with camera, but to accomplish the entire observation task as automatic as possible
Three-Dimensional Numerical Simulation of Mixed Convective Heat Transfer in a Horizontal Rectangular Duct Utilizing Nanofluids
Authors: Om Nur Irmawati , Mohammed H.A.
Published: August 2014

Predictions are reported for three-dimensional laminar mixed convective heat transfer using nanofluids in a horizontal rectangular duct. Five different types of nanoparticle, Ag, Al2O3, Au, Cu and SiO2 with nanoparticles volume fractions range of 2% to 10% are investigated. In this study, the effects of nanofluids type, nanoparticles volume fraction of nanofluids and the effect of aspect ratio on the thermal fields were examined. Results reveal that the addition of nanoparticles to the base fluid and their volume fraction tend to increase the Nusselt number along the horizontal rectangular duct (i.e., increases the rate of heat transfer). It was also found that the Nusselt number increases as the aspect ratio decreases.
Comparative Study between a Heat Pump and an Electrical Resistance as Energy Support for a Solar Water Heater
Authors: Reis R.V.M. , Maia Antonio A.T. , Machado Luiz , Koury Ricardo N.N.
Published: August 2014

Heating water using solar energy can significantly reduce fossil fuel consumption. However, during the lack of sunlight it is necessary an alternative energy source to supplement or substitute the solar energy. To provide this additional energy, electrical resistances are among the most common devices used. In this work it is presented an experimental analysis of an alternative system to support solar water heating with a better cost-benefit ratio than that of the electrical resistance. For this purpose, a heat pump was designed, constructed and experimentally evaluated as supplementary heating source. To improve the system’s performance, a static evaporator was used as a substitute for the conventional evaporator. The mean coefficient of performance (COP) for the heat pump was 2.15. The same tests were performed utilizing an electrical resistance as heating source and the results obtained in this case were compared with the results obtained using the heat pump. The moderate cost of acquisition and installation of the heat pump allowed an investment return between 2.5 and 3.6 years, depending on the city in which the system is installed. Considering that the equipment has an estimated lifespan of 15 years, the internal rate of return varies from 24.5 to 37.9%, which is attractive for investment.
Buckling and Post-Buckling of Composite Shells with Asymmetric Meshing in Form of Axial Band in Numerical Model
Authors: Tahir Ziaul Rehman , Mandal Parthasarathi
Published: August 2014

Asymmetric meshing is a perturbation introduced in the numerical model without changing geometry, loading or boundary conditions. Asymmetric meshing is employed in the form of a band along axial direction of the shell model, the elements size in the axial band is reduced as compared with the rest of shell to produce asymmetry in the meshing and four amplitudes of asymmetry are used in a particular band. Asymmetric meshing affects predicted buckling load, buckling mode shape and post-buckling behaviour. The reduction in the buckling load using asymmetric meshing was observed to be about 18%, which depends mainly on area of asymmetric meshing and less on different magnitudes of asymmetry in the same area. The load-displacement curve behaviourusing asymmetric meshing technique is quite similar to the curve obtained by introducing geometric imperfection in the shell model.
Evaluation of the Fatigue Linear Damage Accumulation Rule for Aeronautical CFRP Using Artificial Neural Networks
Authors: Zuluaga-Ramírez Pablo , Frövel Malte , Arconada Álvaro , Belenguer Tomás , Salazar Félix
Published: August 2014

New optimized aerospace structures use composite materials for critical components and subsystems which make essential the knowledge of their fatigue properties. In the present work, the conventional methodology based on linear damage accumulation rules, applied to determine the fatigue life of structures subjected to spectral loads was evaluated for an aeronautical Carbon Fiber Reinforced Epoxy composite material. A test program has been performed to obtain the classical S-N curves at different stress ratios. Constant life diagrams, CLDs, where determined by means of Artificial Neural Networks due to the absence of consistent models for composites. A series of coupons have been tested until failure with a modified version of the standard FALSTAFF load sequence and were compared to the theoretical damage index calculated based on the conventional linear damage accumulation rule. The obtained results show non-conservative predictions.
The Masonry Crack Propagation Simulation Based on LS-DYNA
Authors: Lou Ya Fei , Sun Bai Tao , Zhang Xuan
Published: August 2014

Due to the development of the computer hardware and the difficulties in determining the constitutive relation, it is difficult to research the crack propagation of large-scale masonry with the finite elements analysis method. The paper analyses the single storey concrete block masonry experimental model with the software LS-DYNA, using winfrith concrete material model instead of masonry material. And the calculated results were compared with the test results. The comparison indicates that the crack propagation of masonry can be simulated better with winfrith material model, which can be used in the finite elements analysis of large-scale masonry.
The Dynamic Measuring Method of Nondestructive Testing the Overall Performance of Some Frame Shear Wall Structure
Authors: Zhao Yun Qing , Zhang Yong Sheng , Jiang Wei Tao
Published: August 2014

Dynamic test method is a more accurate method of indirect nondestructive testing. The dynamic characteristics of the buildings is obtained by dynamic response of high sensitivity under external excitation vibration pickup structure. The test of a reinforced concrete frame shear wall structure of a complex building was carried on as an example, and the evaluation of the overall performance of the structure was made through the test results.
Compressive Characteristics with Variation of Length of Shear Connections for Steel-Plate Concrete Structures Adding Hwangtho
Authors: Park Ho Young , Choi Byong Jeong
Published: August 2014

In the study, as an attempt to apply to the general low-rise structure among the developed SC structure systems for special structure, a usability test was planned by replacing the existing concrete of SC structure with red clay (Hwangtho) for weight lightening and eco-friendly structure with less carbon dioxide. Also, a comparison between the test result and the domestic standard KEPIC-SNG was made. As a result of the test, compression strength of the red clay added specimen showed 4~20% more stable result compared to the KEPIC-SNG.
The Heat Upsetting Process for the Titanium Alloy Spherical Bone Screws
Authors: Liu Jian Guang , Liu Feng Lei , Liu Hua Dong , Wang Yu Feng , Wang Li Dong
Published: August 2014

An advanced heat upsetting technology was studied according to the characteristics of the titanium alloy medical bone screws with spherical head. First, the reasons that punch demoulding is difficult during the upsetting forming have been discussed. Then the forming way with countersunk head in bottom and free forming on top was adopted, and the segmented upsetting die ranging in inner diameter was designed. Finally, the continuous heat upsetting process for medical bone screws was developed. The size, hardness and microstructure of the developed screws meet the standard requirements.
Research on Seismic Strengthening with the Performance of the Dynamic Measurement Method
Authors: Zhang Jian Jian , Zhang Yong Sheng
Published: August 2014

The structure of the dynamic characteristics can comprehensively reflect the seismic performance of the structure. By high sensitivity under external excitation vibration pickup pick structure dynamic response to obtain the dynamic characteristics of buildings, this paper introduces the principle of vibration test and modal identification method of information. To high-rise shear wall of reinforced concrete frame structure of a residential building as an example, has carried on the test, through the test results of the seismic performance of this structure after reinforcement.
Motor Speed Detection Based on Single Chip Microcomputer and Waveform Recording System Design
Authors: Ma Shu Qing , Wang Chuan Jun
Published: August 2014

this article is to use AT89C51 single-chip microcomputer control of intelligent speed measuring instrument. Motor in the process of operation, need to be monitored, speed is a necessary one parameter. This system is carried out on the motor speed measurement, and can be conducted and PC communication, shows that the speed of the motor, and observe the basic condition of the motor running. Mainly USES AT89C51 as the control core, by hall sensors, LED digital tube, the NE555, L298N, operational amplifiers, etc. SCM measuring speed system was introduced in detail. Give full play to the performance of the single chip microcomputer. The focus is on measuring speed and display. Its advantage is hardware circuit is simple, software function is perfect, measuring speed, high precision, reliable control system, the characteristics of high performance-to-price ratio.
Experimental Studies of Mechanical Vibration Assisted Induction Heating Hot-Pressing
Authors: Wu Fei , Zhou Zhao Yao , Dong Meng Long , Yao Bi Bo
Published: August 2014

A new method of mechanical vibration assisted induction heating hot-pressing was proposed. A set of apparatus was developed to perform the forming of mechanical vibration assisted induction heating hot-pressing. A series of experiments of induction heating temperature characteristics of different kinds of powder was carried out, such as Fe powder, Al powder and SiC powder. The results show that different kinds of powder reach different equilibrium temperatures and have different temperature characteristics under the same condition of setting temperature and cyclic heating times. SiCp/Al composites were prepared by induction heating and vibratory forming and observed by metallographic microscope. It turns out that completely dense and homogeneous powder metallurgy compaction is compacted and sintered at the same time by the method of mechanical vibration assisted induction heating hot-pressing with low pressure and short time.
The Static and Modal Analysis of 12000KN Fine Blanking Press Frame
Authors: Xiong Rui , Zhu Chun Dong , Li Xin Yu
Published: August 2014

The fine blanking press supports huge impact load and high-speed stamping frequency in the work process, and the deformation of the molds and the precision of components are significantly influenced by the deformation and vibration of the press. The frame under impact load and stamping frequency, thus the frame structure is the key factor to ensure the reliable work. To make the virtual prototype of the 12000KN fine blanking press frame meet requirements in the best way, the concept design of the frame was built. And optimal interval of the frame stiffness and first order natural frequency were find according to finite element analysis, which can lay the foundation for the design of an ideal frame.
Research of Particle Mechanics Application Based on Conveying Machinery
Authors: Xu Zhi Qiang
Published: August 2014

The conveyer belt is a major component of the conveyor , whose cost accounted for half of the of the entire cost of the conveyor. The loss of the conveyor is mainly due to the use of friction and wear generated in the process, so study on the friction characteristics is very meaningful. The friction and wear of the conveyor is one of the factors affecting their life. Therefore, conducting applied research on belt conveyors and mechanical analysis becomes increasingly important. In this paper, some qualitative research on the mechanical properties is carried out, starting from the application of the conveyor belt.