bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement and Analysis on the Concentration of Dust of Various Diameters in a Foundry Workshop
Authors: Song Gao Ju , Yang Lei , Cheng Ai Xia , Guan Ren Bo , Shen Heng Gen , Qiang Tian Wei
Published: October 2014

The particle concentration distribution in the foundry is very important not only for the occupational health of foundry workers but also for creating green foundry industry. In this study, the authors measured the particle concentration distribution in a foundry workshop, and analysis the characteristics of foundry dust pollution with the consideration of total dust control in the recent foundry industry. The results show that the concentrations of PM10 and PM2.5 are high in the central and low in the ends of the workshop. It is about 54% of all test sites with higher concentration of PM10 and PM2.5 than the limit values of national standards. However, the PM4 concentrations of about 31% test sites are higher than limit of national standards. It is obviously that sandfilling process, cavity repair and sweeping in mold making process can produce a lot of dust. This study may provide guidance for the foundry pollution control engineering and workshop operation management system.
Research and Design for Electromagnetic Leakage Detector Based on Induction Coil Method
Authors: Qian Jiang Shan , Song Jia Jia , Zhang Jin Bo
Published: October 2014

With more and more electronic products used in daily life, as well as people attach great importance to our survival environment, people are more and more concerned about electromagnetic leakage pollution generated from electronic products. So the study of electromagnetic leakage detector that can rapidly and accurately detect the electromagnetic leakage in electronic products is significant. In this paper, we design a fast and effective 3-D electromagnetic leakage detector, which using three hollow induction coils which are mutually vertical between each other to obtain the intensity of electromagnetic field. With this instrument, the intensity in three directions can be tested at the same time. Tests revealed that electromagnetic leakage detector can easily measure the 3-D intensity of electromagnetic leakage generated from low frequency electronic products. It provides an important basis for inspection department to detect electromagnetic leakage in electronic products.
Research of AdaBoost Face Detection and OpenCV Implementation
Authors: Shi Chun Lei , Yang Dan Dan , Jiang Guang Yuan
Published: October 2014

We introduce the principle of AdaBoost face detection algorithm based on Haar-like feature in detail, and use OpenCV face detection module to realize AdaBoost algorithm on CMU face library. Experimental results show that the algorithm receives good effects. Meanwhile we analyze the relationship between the number of simple classifier and face detection result.
Simulator of the SAR Echo Based on FPGA
Authors: Yuan Chang Shun , Wang Jun , Tao Lei Yan
Published: October 2014

The echo simulator has great significance to the research on synthetic aperture radar (SAR), but massive computation and longer time are needed. In order to realize SAR echo simulation fast, the field programmable gate array (FPGA) is adopted as the kernel chirp to design the digital signal processing board to be specially used in SAR echo simulation. The simulation algorithm is realized on the board by programming. The application result shows that the realization of SAR echo simulator based on FPGA can greatly accelerate the simulation speed and significantly reduce energy consumption.
Numerical Analysis of the Influence on High Humidity in a T-Joint Fillet Weld for High Strength Low Alloy Steel
Authors: Chen Song Ping , Li Yong Xian , Xie Yan Ji
Published: October 2014

Welding at high humidity is frequently needed for the harbor hoisting machinery of steel structures in the coastal port city. A computational procedure is proposed for analyzing residual stress and temperature distributions induced by the T-joint welding in two types of St52-3 high strength low alloy steel plates both 6 mm in thickness. The relative humidity conditions varied from 75 to 90% at constant pressure. The finite element models are employed to evaluate the transient temperature and the residual stress during welding. According to the analysis results, the higher residual stress and the highest concentration of hydrogen are distributed in and surround the heat affected zone (HAZ), and vary with different humidity.
A Design of Innovative Experiment Platform Based on the Research of Flapping-Wing Aircraft
Authors: Zhu Bing  Hao , Jin Xiao Yi , Zhao Li Li , Zhang Jing Yuan , Tao Hua Cheng
Published: October 2014

According to the fact that it need several tests to determine the size and motion parameters of the flapping-wing aircraft in the development processes, the paper proposed a design scheme of flapping wing system experimental platform. Separately from the scheme, the system platform, driving mechanism design, motion parameters change, described in detail the design and implementation of this innovation experiment platform. Users can simulate and debug the platform system to determine the performance of the flapping-wing mechanism.
A New Rate-Dependent Prandtl-Ishlinskii Model for Piezoelectric Actuators
Authors: Liu Zi Chao , Pan Wei , Lu Chang Hou
Published: October 2014

This paper presents a new rate-dependent model for piezoelectric actuators. The proposed method directly utilizes a modified rate-dependent Prandtl-Ishlinskii hysteresis model to characterize the hysteresis and frequency effect of piezoelectric Actuators quickly and efficiently. To identify the model parameters, the least square method is adopted. Based on the identified model parameters, the rate-dependent model for Piezoelectric Actuators is established. By comparing the rate-dependent model with the real output of the Piezoelectric Actuators, the result shows that the new rate-dependent model could characterizes the hysteresis and frequency effect of Piezoelectric Actuator, which clearly demonstrates the effectiveness of the proposed Rate-Dependent Prandtl-Ishlinskii Model.
A Study on the Location System Based on Zigbee for Mobile Robot
Authors: Zhang Lei , Zhang Shen , Leng Chun Tao
Published: October 2014

As a wireless communication technology, Zigbee has been used in the mobile robot’s location in recent years. An experimental system composed by a Zigbee network, a PC and a robot is designed to study the location accuracy of Zigbee location technology. The hardware and software platform are constructed. The influence of the layout and the number of reference nodes on the location accuracy is discussed. The results show that ZigBee-based robot position method can meet the requirements of mobile robot applications. The location accuracy in the layout of triangle is up to 0.636m (in the range of 4m4m) and is better than those in the layouts of rectangle and cycle .
Protection of Kapton from Atomic-Oxygen Erosion Using a Polysilazane Coating
Authors: Chang Yu Chuan , Liu Ting Zhi , Zhang Hao , Duo Shu Wang
Published: October 2014

The polysilazane synthesized by aminolysis of dichloromethylviny was coated on kapton by dip-coating method, the AO exposure tests was carried out in a ground-based AO simulator. It is found that the erosion yield of kapton was decreases by about two orders of magnitude. After exposure the coated katpon still have a smooth surface, and its optical properties are still at a high level. The polysilazane coating exhibits a superior AO erosion resistance.
Application of RBF Neural Network in the Manipulator Trajectory Planning
Authors: Du Meng Meng , Zhang Hai Tao
Published: October 2014

In view of the high order, nonlinear characteristics of target trajectory, control strategy is proposed for a kind of RBF neural network and polynomial interpolation combining. According to the specific requirements of trajectory planning, the manipulator in joint space variables are expressed as one or two order derivative function by polynomial interpolation algorithm, then the RBF neural network is used for tracking the target trajectory. Finally, through MATLAB simulation, the accuracy of this method is verified.
Comparison of Curved Surface Part Finishing Simulation Based on CAXA
Authors: Song Yu Mei , Du Qiu Lei , Hou Yue Qian , Zhang Hai Feng
Published: October 2014

Choosing five kinds of curved surface finishing methods is commonly used in CAXA and processing compared to the same curved surface parts, on the premise of making the parts same residual height and exploring their selection principle.
Current Status and Tendency of Development in Vehicle In-Arm Suspension
Authors: Gao Xiao Dong , Gu Liang , Guan Ji Fu , Gao Jun Feng
Published: October 2014

In-arm hydro-pneumatic suspension unit (ISU) is a kind of hydro-pneumatic suspension, it has been researched for 30 years. Nowadays, there are three companies in mass production of ISU. In this paper, the growth and ISU products of these companies are introduced, the main characteristics of ISU are discussed, and the main application of the hydro-pneumatic suspensions are presented.
Design of Semiconductor Thermoelectric Generation Control System Based on MCU
Authors: Yu Chun Xiao , Li Yan Ying , Wang Chang
Published: October 2014

Based on the characteristics of semiconductor thermoelectric generation, this paper takes STC12C5410AD MCU as the core, and designs an intelligent lead-acid battery charging and discharging controller. It implements the intelligent switch, overload overcharge protection of charging way, and can automatically switch between power generating system and battery according to battery load circuit. It realizes the effective transformation of heat into electricity, intelligent storage and utilization.
High-Sideslip Model Reference Adaptive Flight Control for Aileron Locked Aircraft
Authors: Cheng Peng Fei , Wu Cheng Fu , Guo Yue
Published: October 2014

This paper develops a high-sideslip flight control scheme based on model reference adaptive control (MRAC) to stabilize aircraft under aileron deadlock of one side. Firstly, the cascaded flight control scheme for high-sideslip straight flight is presented and how the control signals transfer is also analyzed. After that, the control structure and laws of MRAC for attitude inner-loop connected with sideslip command are designed. Finally, the control scheme is verified under a nonlinear aircraft model in conditions of no fault and one side aileron deadlock respectively. The simulation results show that when one side aileron deadlock occurs in accompany with the plant’s aerodynamic data perturbation and random initialization of controller parameters, this control method could utilize operation points of no-fault aircraft to force the faulty aircraft following the given reference model responses and finally tracking given sideslip angle command without static error robustly.
Innovative Design for Function of Withdrawing from ATM Based on PFGA
Authors: Jin Han Chen
Published: October 2014

By applying the technology of FPGA to solve the problem which derives from various Internet interruption of safety on management about controlling system of digital ATM(Automatic Teller Machine), specifically analyze the basic withdrawing function of ATM. According to the fundamental method of withdrawing, starting from the procedure of designing circuits, then focus on research about the principle to manage ancillary equipment and following LED circuits by means of applying FPGA which use the essential hardware language Verilog to accomplish this mission on the interface of software Xilinx ISE, then after simulation and finally download the source code to Basys2 to verify the accuracy of withdrawing function. In all, it's an innovative design of withdrawing function of ATM based on FPGA board and hence ensure the absolutely safety of customers' individual information in ATM.
Observer-Based Dynamic Output Feedback Controllers Design with Packet Dropouts for Augmented Switched System
Authors: Wen Dan Li , Ma Qin
Published: October 2014

This paper was concerned with observer-based dynamic output feedback controllers design with packet dropouts for augmented switched system, the packet dropouts existing both from the sensor to the controller and from the controller to the actuator. Stability controllers via observer-based dynamic output feedback is constructed for the switched system by using an LMI-based method.
Research on Kinematics Joint Type Mobile Robot Platform for Thin Coal Seam Inspection
Authors: Shang De Yong , Zhao Jian Wei , Liu Na , Zhang Yun Long , Fan Xun
Published: October 2014

Due to the high labor intensity of the maintenance workers, the narrow space and harsh environments in mining process of thin coal seam, an inspection robot to adapt to the thin seam environment instead of workers for the inspection work is urgently need . In this paper, we research on a bionic joint type inspection robot motion platform in thin coal seam, and study the kinematics analysis, which is a theoretical foundation for this kind of the robot platform control.
Research on Technology and Application of Multi-Sensor Data Fusion for Indoor Service Robots
Authors: Ma Xi Pei , Qian Bing Feng , Zhang Song Jie , Wang Ye
Published: October 2014

The autonomous navigation process of a mobile service robot is usually in uncertain environment. The information only given by sensors has been unable to meet the demand of the modern mobile robots, so multi-sensor data fusion has been widely used in the field of robots. The platform of this project is the achievement of the important 863 Program national research project-a prototype nursing robot. The aim is to study a mobile service robot’s multi-sensor information fusion, path planning and movement control method. It can provide a basis and practical use’s reference for the study of an indoor robot’s localization.
Simulation on Dynamics of Transmission Shaft-Rear Driving Axle of Minibus with ADAMS
Authors: Zhang Chen Xia , Li Hui Bin , Jin De Quan
Published: October 2014

Simulations on the dynamics for the transmission shaft-rear driving axle of minibus were conducted with ADAMS. By using ADAMS software, the multi-dynamic model of the transmission shaft-rear driving axle was set up and then effects of the equivalent transmission shaft angle’s variation and transmission shaft rotating speeds on the rear driving axle’s vibration were analyzed. With the increase of the equivalent transmission shaft angle’s variation and transmission shaft rotating speeds, the vibration of the rear driving axle will also increase. These simulation results will give help to further study of the NVH characteristic of the rear driving axle.
Study on the Improvement of Color Image Enhancement Algorithm for Robot Vision System
Authors: Zhao Yun
Published: October 2014

Under the influence of external dynamic lighting or outdoors strong light, image color have a great influence on rapid and accurate positioning of the robot, which requires the robot vision system to obtain the high quality of color image. This paper uses the image pixel conversion ratio algorithm to improve the image recognition algorithm of robot vision system, and the use of multi threshold segmentation technology carries out restructure for image, it can get the high resolution image enhancement effect. In order to realize the algorithm, the form of using VB programming carries out algorithm implementation, and then the image enhancement can calculate the enhanced results table of image color curve distribution and different segmentation threshold image resolution. From the simulation results, this algorithm can enhance the image color effect, which provides technical support for the development and design of robot vision system.
The Optimized Design of FIR Digital Filter Based on FPGA
Authors: Zhang Hong Wei , Duan Xin Wen
Published: October 2014

With the development of communication and computer, the importance of digital filter highlighted. FIR digital filter can satisfy arbitrary amplitude frequency characteristic, at the same time, it can keep accurate and strict linear phase characteristic. So it has been most widely used in digital signal processing (DSP) in the modern society. After comparing several kinds of FIR digital filter methods, this paper studies in details the realization of principle and method of FIR filter based on FPGA and MATLAB while adopting a distributed algorithm. Finally the optimal design method is proposed and simulated.
Steam Reforming of Ethanol by a Nickel Nanowire Catalyst
Authors: Hong Xue Bin
Published: October 2014

A nickel nanowire catalyst was prepared by a hard templating method, and characterized by transmission electron microscopy (TEM), N2 physical adsorption, X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD) and H2 temperature-programmed reduction (H2-TPR). The catalytic properties of the nanowire catalyst in the ethanol steam reforming were compared with a metallic Ni catalyst which was prepared with nickel sponge. The characterization results showed that the nickel nanowire catalyst had high specific surface area and there was more NiO phase in the nickel nanowire catalyst than in the metallic Ni catalyst. The reaction results showed that the nickel nanowire catalyst had higher ethanol conversion and hydrogen yield than the metallic Ni catalyst.
Underwater Radiated-Noise Simulation Control Model Based on Propeller Influencing
Authors: Ju Yang , Zhang Zhe , Wang Xin Yong , Xu Hai Sheng
Published: October 2014

Underwater target radiated-noise of time domain is significant important in underwater defense and security. Its simulation model based on propeller influencing is considered in this paper. Linear difference equation representing relationship between underwater target radiated-noise of time domain and propeller induced noise is fitted from the data. Dynamical programming is employed to investigate the control of the target radiated-noise. Experimental results show the efficiency of our model and the control methods.
An Effective Single Passive Location Method Based on Near Space Vehicle for Ground Fixed Emitter
Authors: Liu Fu Lai , Jia Hui
Published: October 2014

Ground target position estimation of near space vehicle is the key technology in military and civilian field. In this paper, we propose an effective method using the cubature Kalman filter (CKF) based on direction of arrival (DOA) and its rate of change. Comparisons with the location method only using DOA and the classic EKF algorithm are conducted respectively. Simulation results indicate that the proposed method has faster convergence speed and better location precision.
Simulation-Based Helicopter Mission Effectiveness Evaluation Method
Authors: Cai Ji , Liu Hu , Tang Hong
Published: October 2014

It is always difficult to obtain a reliable result of helicopter mission effectiveness evaluation (HMEE) by traditional methods. In order to solve the problem, this paper compared and analysed advantages and disadvantages of traditional effectiveness evaluation methods, and presented a simulation-based helicopter mission effectiveness evaluation method. The method is based on the simulation data. The method combines with advantages of multi parameter evaluation method, computer simulation evaluation method and logarithmic evaluation method. By using the reliable helicopter flight simulation data and an objective weight coefficient calculation methods, we can get accurate and reliable helicopter mission effectiveness value. Research proves that this method can be applied in the field of effectiveness evaluation.
The Application of GPC Algorithm on Network Predictive Control Based on Toeplitz Equation
Authors: Bin Rao
Published: October 2014

Network latency was usually uncertain or random, and the packet loss and temporal disorders could also be attributed to a certain degree of time delay. This paper briefly described the basic principle of predictive control and deduced the predictive control algorithm based on Toeplitz equation, finally combined with the simulation example to verify the validity and superiority of the new algorithm, from the operation speed of the algorithm, the signal tracking capabilities when time delay existed, and performance for overcoming the influence of model mismatch.
A Wide Bandwidth, Byproduct Harmonic Cancelling Frequency Multiplication Technique for mmWave and Terahertz Applications
Authors: Wang Le Yi
Published: October 2014

This paper presents a frequency multiplication technique using travelling wave. The proposed technique improves conversion efficiency, cancels byproduct harmonics, and achieves wide bandwidth. citive pressure sensor by means of frequency shifts from its nominal operation frequency. It takes advantage of standing-wave formation and loss cancellation in a distributed structure to generate high amplitude signals resulting in high harmonic power. Wide bandwidth operation and odd harmonic cancellation around the center frequency are the inherent properties of this frequency multiplier.
Indoor Mobile-Robot Path Panning Based Bird’s Eye View Images
Authors: Yuan Ye , Liu Lei , Sun Yu Kuan , Wang Jian Ming
Published: October 2014

Navigation is essential function for a mobile robot to make it navigate in its environment. The navigation based on bird’s eye view images is a newly proposed indoor visual navigation framework, which can help to simplify the navigation problems, such as self-localization, map-building, path planning and other competences. In the paper, a path planning algorithm applied to the indoor visual navigation is proposed. Firstly, three planning conditions are adopted as the constraints for algorithm design, and then the algorithm is explained. Finally, simulation and practical experiments were implemented and the results were analyzed.
The Analysis of Positioning Performance and DOP Value Based on BDS/GPS Integrated Navigation Satellite System
Authors: Yuan Wei Lin , Ma Yan , Sun Hua Bo
Published: October 2014

The integrated positioning system increases the visible number of single satellite navigation system and improve the DOP value of single satellite navigation system. In accordance with the construction plan, BeiDou Navigation Satellite System (BDS) has started providing continuous passive positioning, navigation and timing service in the most parts of the Asia-Pacific In this paper, DOP value of GPS, BDS and the integrated navigation system are analyzed theoretically. The improvement of DOP value of GPS which resulted from present-running BDS navigation satellites is calculated by GPS/BDS observational data. The conclusions that GPS/BDS integrated navigation system will be able to improve the positioning accuracy and have useful references for the navigation and positioning application are also obtained.
Ultra-Precision Polishing Methods for Sapphire
Authors: Bao Hui Xue , Liu Qiang , Zhou Xiao Qin
Published: October 2014

Sapphire (Al2O3 crystal) is a hard and inert material with good mechanical, optical, physical and chemical properties that plays important roles in optics and electronics. The surface quality is the key element of sapphire components especially in optical field. This paper mainly introduces four methods of ultra-precision polishing, researches based on polishing theories and slurry. It can be a conclusion that traditional polishing methods can improve material removal rate assisted by ultrasonic.
The Convergence of Coupled Boundary-Layer Equation in the Contact Interface
Authors: Hou Lei , Faraz N. , Sun X.Y. , Zhao J.J. , Qiu L.
Published: October 2014

This paper introduces two equations of non-Newtonian boundary-layer fluid: Cauchy equation of flow field and P-T/T equation of stress field. Secondly, we analyze the convergence of this system of fluid-solid coupled equation with semi-discrete finite element method. We use Galerkin finite element method on the space and semi-implicit C-N difference scheme on the time. Thus, the convergent order of the coupled equations is O（h2+k2） .
Discriminative Minimum Statistics Projection Coefficient Feature for Acoustic Context Recognition
Authors: Deng Shi Wen , Zhang Chao Zhu , Wang Chao
Published: October 2014

Acoustic environment recognition, which can provide the important acoustic context, has been widely used in many applications and is a considerable difficult problem in the real-life and the complex environment. This paper proposes the discriminative minimum statistics project coefficient (MSPC) feature with the information of classification by using partial least squares (PLS). With the minimum statistics (MS) tracked from the input sound, the discriminative MSPC feature is extracted by projecting the MS into lower-dimensional feature subspace learned by using PLS analysis. Based on the proposed discriminative MSPC feature, the acoustic environment recognition is implemented by using Gaussian Mixture Model (GMM) for modeling each sound class. The experimental results show that the proposed discriminative MSPC feature based on PLS outperforms the MSPC feature based on PCA for acoustic environment recognition.
SS-BMUSIC Algorithm for Space-Time 2D Signal Model
Authors: Jun Yang , Feng Qi
Published: October 2014

This paper presents a beamforming matrix with spatial smoothing effect, and extends it to the space-time 2D signal model, which not only reduces the computational complexity of the space-time 2D MUSIC algorithm and improves the coherence resolution capacity, simulation results show that this algorithm has better performance and effectiveness than MUSIC itself.
A Multi-Source Dynamic Determination Algorithm for Digital Synchronization Equipment
Authors: Zhang Bin , Chen Bao Ren , Zhuo Yue , Wang Guang Cai , Ding Yi Jie
Published: October 2014

In order to improve the security and reliability of digital synchronization network, digital synchronized equipment mostly uses reference source design and ensure the output performance in abnormal situation by redundancy back-up of multiple reference sources. The paper not only describes the concept of time-frequency equipment reference source and its judgment index, but also details a multi-source dynamic determination algorithm for digital synchronization equipment. A multi-component weighted average approach is designed the multi-source dynamic source selected processes by the study of several time sources of anomaly detection to improve the accuracy of the synchronization signal. The algorithm with simple structure can help keeping the high synchronization accuracy of multi-source time synchronization system.
Numerical Investigation of Flow Past a Backward-Facing Step Using a Multi-Scale Turbulence Model
Authors: Dong He , Li Zhi Qiang , Gao Ge , Shi Zhong , Guo Jian , Tang Wen Dong
Published: October 2014

The flow past a backward-facing step was simulated using both the multiscale turbulence model based on the variable interval time average method and the standard k-ε model based on the Reynolds average method. The numerical method used in this simulation is an unstructured staggered mesh scheme. The capability of the multi-scale model to simulate flow past a backward-facing step has been validated. Both pressure coefficient and mean velocity profiles downstream are in agreement with experiments. Moreover, the results predicted by the multi-scale model are better than that predicted by the standard k-ε model. The computational results show that the multiscale turbulence model can successfully simulate this type of separated flow.
Method for Determining Energy-Consumption Benchmark State in the Thermal System of Coal-Fired Units Based on Hybrid Model
Authors: Zhu Long Fei , Wang Ning Ling , Fu Peng , Yang Zhi Ping
Published: October 2014

Considering the varying operation conditions and ambient constraints, the in-depth energy conservation of thermal power units is confronting new challenges. Based on the already made ‘energy-consumption benchmark state’ concept, the description of energy-consumption benchmark state was obtained in this paper to describe the economic performance of coal-fired power thermal system with the varying operation boundary, operation conditions and equipment performance. Breaking the limitations of traditional modelling which always make statistic analysis and mechanism analysis isolate, hybrid modeling method synthesizing the merit of the mechanism analysis and statistical method was proposed. Considering the heat transfer characteristics of thermal system, this model make the energy-consumption of unit correspondence with parameter sets of thermal system. Optimized parameter sets were gained with the fuel specific consumption setting as the optimization objective, thus obtain the energy-consumption benchmark state in thermal system of coal-fired units. The results show that the method for determining energy-consumption benchmark state in the thermal system of coal-fired units based on hybrid model makes significant reference for the energy-saving diagnosis and operation optimization of thermal power units under overall working conditions.
On a New Parallel Tracking System for Accurate Orientation of Concentrated Solar Convertors
Authors: Neagoe Mircea , Visa Ion , Cretescu Nadia , Moldovan Macedon
Published: October 2014

The concentrated solar energy convertors (e.g. solar-thermal dish, concentrated photovoltaic) require high tracking accuracy to maintain low incidence angles of the solar ray in relation with the concentrator optical axis (e.g. tracking accuracy of 0.05°...0.1°). This functional requirement is currently ensured by the high performance dual-axis solar tracking systems, able to reach the imposed accuracy, including expensive rotary actuator solutions. This paper proposes a new high accuracy tracking system for diurnal orientation, integrating a 2 DOF parallel linkage driven by linear actuators, as a simple, accurate, and cost-effective solution. A kinematic and static approach used for optimisation of the driving programs of the two linear actuators is presented, following the requirements: a) ensure the imposed tracking accuracy and b) achieve advantageous transmitting angles and hence lowest driving forces. The performances of the system are analysed on large orientation strokes (over 130°); the results obtained confirm the viability of the new tracking system concept, with higher performances compared to other similar known solutions.
Geometrico-Static Modeling and Simulation of the Contact between Chain and Guide of a Reference Transmission
Authors: Papuc Radu , Velicu Radu , Lates Mihai Tiberiu , Jaliu Codruta
Published: October 2014

In order to evaluate friction losses from chain drives, an important aspect to regard is the friction between chain and guide. This paper is proposing a mathematical model and simulation of the chain-guide contact, for a reference chain drive with transmission ratio equal to 1. The transmission is subject of further experimental determination of friction losses.
Planetary Gear for Counter-Rotating Wind Turbines
Authors: Saulescu Radu , Jaliu Codruta , Munteanu Olimpiu , Climescu Oliver
Published: October 2014

A specific problem of the wind turbines refers to the difference between the low rotation speed of the wind turbine rotor and the high rotation speed needed for the electrical generator. Usually, the adaptation between the speed of the turbine rotor and the electrical generator speed is achieved by means of a speed increaser. A recent alternative relates to the use of coaxial counter-rotating wind turbines, which can achieve higher power and improve the conversion efficiency of the wind energy into electrical energy (up to 25%) with a reduced cost of approx. 20-30% compared to similar single rotor turbines. Conceptually, the counter-rotating wind turbine systems can integrate a particular generator wherein the rotor is coupled to a row of blades and the stator with another row of blades, or a commonly generator, coupled to a differential planetary gear, that allows the summation of the blades motions.The paper describes and analyzes kinematic and dynamic aspects of a system consisting of two coaxial counter-rotating turbines and a generator, interconnected by a planetary gear with two inputs (the two turbines) and an output (the generator). The algorithm is based on the property of the differential planetary gear of adding two input motions into one output motion. The kinematic and dynamic parameters of the planetary gear are established in the paper, and a case study is further presented: a small wind turbine equipped with a transmission enabling input speed multiplication.
Stress Analysis and Optimal Design of the Housing of a Two-Stage Gear Reducer
Authors: Cojocaru Vasile , Korka Zoltan Iosif , Miclosina Calin Octavian
Published: October 2014

The design of the housings of the gear reducers is made, usually, using empirical equations based on the center distance (the distance between shafts). These equations can lead to inappropriate stresses distribution and inadequate material consumption at the final product. In the manufacturing of large series and in the manufacturing of the gear reducers/ gearboxes with large dimensions it is necessary an optimization of the housing dimensions. The use of the finite element analysis in this process, combined with experimental researches, can generate significant improvements. The paper is focused on the analysis of stresses distribution and displacements on the housing of a two-stage helical gear reducer with parametric dimensions and loads. The housing is subjected to a static finite element study. The optimization process aimed to minimize the total weight of the housing. The next features were submitted to dimensional changes: the thickness of the housing walls and the thickness of the ribs. The results presented as diagrams of stresses and displacements distributions show real opportunities to reduce the total weight of the housing and the material consumption.
Influence of Several Parameters on Simulating the Ballistic Impact on a Homogenous Plate
Authors: Pirvu Catalin , Badea Simona , Deleanu Lorena
Published: October 2014

This paper presents a simulation of a bullet impact on a plate made of a homogeneous and isotropic material. The developed model takes into account the yield and fracture limits of both involved materials for the bullet and the plate one. The model was developed with the help of Ansys 14.0 and could be used to establish a theoretical value of the plate thickness that will offer protection to the bullet penetration in order to minimize the number of laboratory tests for evaluating the plate resistance. The authors presented the influence of impact velocity of the bullet. The bullet velocity just reaching the plate is an essential parameter influencing the plate integrity. Also, the authors established a correlation between the evolution of the theoretical maximum von Mises stresses and the stages taking place during the impact.
An Analytical Solution for Three-Dimensional Elliptical Elastic-Plastic Rolling Contact
Authors: Popescu Gabriel
Published: October 2014

An analytical three-dimensional elastic-plastic over-rolling solution is used to evaluate the plastic strains and residual stresses. Central to this plastic contact formulation is the incremental approach to deal with non-linear material behavior. The Prandtl-Reuss constitutive equations in conjunction with Huber-Mises-Hencky yield criterion and Ramberg-Osgood strain-hardening relationships are applied to describe the plastic behavior of common hardened bearing steel. The model was extended to include the tangential force in the rolling direction, assumed to be proportional to the hertzian contact pressure. Comparisons of three-dimensional pure rolling and rolling/sliding contact results were provided to elucidate the differences in residual stresses and residual profiles in case of kinematic and work-hardening materials.
Mechanical Behavior of Guitar Neck under Simple Bending Stress Analyzed with Finite Elements Method
Authors: Stanciu Mariana Domnica , Curtu Ioan , Mocanu Teodor
Published: October 2014

This paper presents the results of the FEM analysis of the mechanical behavior of guitar subjected to simple bending. Deformation of guitar neck by string tension constitutes a quality defect of finished product - guitars, which affect the acoustic of instrument. The neck bending modified length guitar strings which leads to obtaining false sounds. Therefore, the aim of the research was to establish the stresses and strains state of the guitar neck in terms of varying the position and force size and contour conditions. It was found that both deflection and stress are maximum values when force is applied on joint area between neck and guitar body. Stiffening of the guitar neck by increasing section or by using stiffer material can conduct to lower displacements, irrespective deformations of guitar neck.
Experimental Determinations of the Eigenmodes for Sandwich Bars with Different Core Reinforced with Metal Fabric
Authors: Miriţoiu Cosmin Mihai , Bolcu Dumitru , Stănescu Marius Marinel , Rosca Vilcu
Published: October 2014

In this paper, starting from the theoretical background of modal identification, it is established an experimental method used to determine the eigenmodes of some composite bars with the core made of polypropylene honeycomb and polystyrene reinforced with metal fabric. The single-point excitation method is used. This method has been widely used in modal tests and it consists in applying a force in a given point and recording the vibratory structure response in all interest points, including the excitation point. Although the single-point excitation requires a minimum of equipment, it needs a laborious analysis to perform extensive result processing in order to interpret the dynamic behaviour of the structure under test.
Influence of the Geometry on the Rolling Friction Torque in Lubricated Ball-Race Contacts
Authors: Balan Mihaela Rodica , Stamate Vasile Ciprian , Houpert Luc , Tufescu Ana , Olaru Dumitru
Published: October 2014

Based on a theoretical model and an experimental methodology for defining the friction torque in a modified thrust ball bearing having only 3 balls and presented in [2], the authors experimentally investigated the influence of the ball diameter on friction torque when operating in mixed and full film lubrication conditions and maintaining the normal load, the race curvature and oil viscosity constant. The experiments were realized using ball diameters between 7.938 mm and 3 mm corresponding to maximum Hertzian pressure between 0.264 GPa and 1 GPa and a rotational speed between 60 rpm to 240 rpm. The experiments confirmed that the measured friction torque can be explained using hydrodynamic rolling force relationships respecting the transition from IsoViscous Rigid (IVR) to ElastoHydrodynamic Lubrication (EHL) regime presented in [2].
Study on the Defects Size of Ball Bearings Elements Using Vibration Analysis
Authors: Bujoreanu Carmen , Monoranu Razvan , Olaru N. Dumitru
Published: October 2014

The vibration analysis aims to extract features from the measurements in order to be used for fault detection and diagnosis. Vibration response measurement is an important and effective technique for the detection of the defects in rolling element bearings. The corresponding analysis methods operate in the time domain, in the frequency domain and recently in the time-frequency domain. A quantitative determination of the defect severity and its development are useful to be determined in order to estimate the remaining useful ball bearing life. Experimental data from a bearing with a defect are collected by an accelerometer then processed to identify the passing time of a ball over a defect. The paper presents a computation model corroborated to an experimental investigation to establish the defect length of a ball bearing inner race.
Wear Prediction in Wheel-Rail Contact under Partial Slip Conditions
Authors: Gavrila George , Cretu Spiridon , Benchea Marcelin
Published: October 2014

This paper presents a numerical model to calculate wear during rolling contact due to micro-slip. Having as initial condition a corrugated rail it is shown the influence of the corrugation wavelength and the dynamic effects of the normal force on the wear creation. Experimental results are presented in order to reveal the influence of roughness when studying the stick-slip phenomenon.
Non Hertzian Contact Model for Tooth Contact Analysis of Spur Gear with Lead Crowning
Authors: Pop Nicolae , Cretu Spiridon , Tufescu Ana
Published: October 2014

The behavior of the contact surfaces between the gear teeth has a significant influence on the gear service properties. An analytical research concerning this behavior by considering a non Hertzian model was developed. A mathematical model of the surfaces of the teeth flanks for modified involute spur gears with crowning and relieving was presented. The pressure distribution, displacement and contact surfaces were analyzed, on considering the load, material characteristics and geometry of the contact surfaces and using a numerical method.
Algorithms for Noncircular Gear Pitch Curves Generation
Authors: Cristescu Bogdan , Cristescu Ana , Andrei Laurenţia
Published: October 2014

The paper resumes the traditional hypotheses for the noncircular mating centrodes design, based on the definition of i) the driving centrode geometry ii) the transmission ratio variation and iii) the rotational motion of the driven centrode. Each procedure is transferred within the gear theory and developed considering both specific gear data, such as gear modulus, gear number of teeth and gear number of rotations during a rotational period. Original codes are developed in Php amd MyQSL to illustrate gears conjugate pitch curves geometry and their kinematics for external rolling.
Interaction of Particles with the Pulmonary Interface: Effects on Surface Elasticity
Authors: Munteanu Bogdan , Berthier Yves , Rieu Jean Paul , Trunfio-Sfarghiu Ana Maria
Published: October 2014

We present an experimental study of the interactions of negative and positive model particles and their influence on the surface elasticity of biomimetic pulmonary surfactant. In this purpose we have measured the adhesion force between negative (G) and positive (GS) particles and supported lipid bilayer by Atomic Force Spectroscopy. In addition, the modification in surface elasticity of lipid monolayer under quasistatic compression when interacting with negative and positive particles was investigated on a Langmuir trough. We found that, positive particles interact poorly with biomimetic pulmonary surfactant, therefore no modifications in surface elasticity were observed. Conversely, negative charged particles interact strongly with the biomimetic pulmonary surfactant, decreasing the surface elasticity. The results are directly relevant for understanding the interactions and the effects of particulate matter on pulmonary structures which could lead to pulmonary surfactant inhibition or deficiency causing severe respiratory distress or pathologies.
Conceptual Design of a Mechatronic System for Supporting Basic Quality of Life of Bedridden Elderly People
Authors: Silva Bruno , Machado José , Carvalho Vitor , Soares Filomena , Matos Demétrio , Pereira Filipe , Bezerra Karolina
Published: October 2014

Ambient Assisted Living is an important subject to be explored and developed, especially in developed countries, due to the increasing number of aged people. In this context the development of mechatronic support systems for bedridden elderly people (BEP) living in their homes is essential in order to support independence, autonomy and improve their quality of life. Some basic tasks as eating, taking a bath and/or hygiene cares become difficult to execute, regarding that often the main caregiver is the other element of the aged couple (husband or wife). This paper presents the conceptual design of a mechanical system especially devoted to assist the caregiver in the handling and repositioning of the BEP. Issues as reducing the number of caregivers, to only one, and reducing the system's handling complexity (because most of the time it will be used by an aged person) are considered. The expertise obtained from the visits to rehabilitation centers and hospitals, and from working meetings, are considered in the development of the proposed mechatronic system.
Innovative Bidimensional Absolute Transducer Based on Video Detection for Positioning into Micro Assembly Processes
Authors: Ardeleanu Mihaita , Ionita Marius , Ivan Alexandru , Gurgu Valentin
Published: October 2014

This paper explains and demonstrates a method to interconnect the video detection data flow with an innovative coded grid in order to precisely associate absolute coordinates to any scanned (micro) objects over a large area, without the aid of external bulky sensors. The concept of measuring micro-objects absolute coordinates is based on a series of coded information markings (micrometric terminal blocks) regularly and precisely printed on the bottom reference surface. In this manner the image processing could extract the values of the coded markings and precisely provide absolute coordinates for the camera image. The correspondence between the object and its absolute coordinates seems therefore straightforward. A very important challenge which must be solved is to read the information in real time, the method solving an optimization problem between the required processing speed and the maximum computing system resources. Finally it was obtained an innovative mechatronic system made of two essential sub-systems: the vision detection for micro-objects absolute reference positioning and characterization and a 3D micro-robotic translator for working space displacement. This system insured automatic scanning of micro-objects over large working spaces, detection process storing all specific information into a unique database file, which the operator can easily use to assign a set of automatic “pick-and-place” tasks for various micro assembly processes, as presented in the application example.
Hardware Structures for High Precision Pneutronic Systems
Authors: Avram Mihai , Constantin Victor , Bucşan Constantin , Besnea Daniel , Spanu Alina
Published: October 2014

Pneutronic systems come with a series of advantages that are natural to working with compressed air, such as the large power/weight ratio of pneumatic actuators, easy and affordable installation and maintenance as well as being clean working systems. However, due to working with compressed air, there are a series of issues, such as static and transient nonlinear behavior, mostly due to the high compressibility of air. Thus, the behavior of such systems is hard to control, especially in terms of precision positioning. The paper deals with proposing three hardware configurations of pneutronic positioning systems in order to assure the imposed positioning accuracy in the presence of disturbances and the preservation in time of the obtained position.
Problems Regarding Singularities Analysis of a 3-RRR Parallel Mechanism
Authors: Buium Florentin , Duca Cezar , Leohchi Dumitru
Published: October 2014

The paper presents some authors results regarding working quality inside workspace of a 3 DoF, 3 RRR planar parallel mechanism, used as parallel robot structure. Namely we deal with singularities avoidance inside workspace as is wide known in scientific literature this represents a major disadvantages of these mechanisms. To this purpose, the configuration determinant notion has been used as principal mechanism work parameter.