bluuebunny/crossref_metadata_2025 huggingface dataset:
The Motional Stability Analysis and Optimal Design of Built-In Chatter Suppression Boring Bar
Authors: Zhang Li Ying , Li Jin Hui , Hu Jun Tao
Published: May 2013

On the basis of the Mechanics and Kinematics analysis of built-in chatter suppression boring bar, the research analyzes the motional stability of built-in chatter suppression boring bar, and uses SIMS vibration absorbers for chatter suppression theory to design the characteristic parameters of vibration absorber; then with MATLAB optimized to get structural material parameters of vibration absorber; finally conduct harmonic response analysis to built two-dimensional model of built-in chatter suppression boring bar by ANSYS, compare and optimize the results to guide the development of built-in chatter suppression boring bar.
The Vibration Response of Large Underground Powerhouse under the Action of Endogenous Power Station
Authors: Wang Jian , Zhang Li Xiang , Guo Tao
Published: May 2013

Atract: Taking the underground powerhouse in a large pumping station as an example, to establish the geometric model of the underground powerhouse structure, and finite element division, analysis of the natural vibration characteristics of the structure, using the method of harmonic response analysis, calculation and analysis to the vibration response of the structure under different conditions. Provide a theoretical basis for the safety evaluation of building structure.
Recognition of Noise Source on Tandem Vibratory Roller
Authors: Li Li Min , Feng Zhong Xu , Zhao Li Ping
Published: May 2013

Original noise of tandem vibratory roller is measured in according to national standard. Using surface noise intensity measurement, noise intensity has been analyzed in including before , after, left and right sides on the roller, left and right sides on the engine and the cab floor. Under the conditions between vibration and no vibration, noise distribution principle is similar and noise source of whole roller concentrated in the position installed engine. Noise source and engine components frequency characteristics have been obtained based on spectrum analysis. The major noise source on the left 7.5m is engine combustion noise, following by exhaust fan noise; the major noise source on the right 7.5m is exhaust fan noise, following by engine combustion noise; leak noise of cab floor is fan and engine combustion noise, meanwhile middle-high frequency noise impact greatly on interior of cab; exhaust noise belonging to broadband noise concentrates in lower frequency and middle-high frequency.
Research on Performance Parameters of the Piezoelectric Vibrator in Ultrasonic EDM System
Authors: Wang Hong Bing , Li Zhi Rong , Sun Chun Hua
Published: May 2013

Ultrasonic EDM which is a novel machining approach for hard materials is developed quickly. In ultrasonic EDM processing the piezoelectric vibrator has a very important influence on the quality of the machining. The purpose of the paper is to study the performance parameters such as the first longitudinal modal frequency, node plane and vibration amplitude of the vibrator . Through FEM (finite element method ) simulation method the relation between structure parameters and the performance parameters are obtained. The results of the paper are very effective to design a vibrator for ultrasonic EDM.
Ground Resonance Analysis of Bearingless Rotor Dynamic Stability Based on Simplified Model
Authors: Wei Li Jun , Li Shu , Li Xue Chang
Published: May 2013

A simplified model of bearingless rotor was investigated using Hamilton principle. The equations of rotor/body coupling system instability were obtained. Perturbed equations were obtained after linearized perturbation. Stability results of rotor blades were presented using eigenvalue analysis. The shape function matrix was obtained using spline interpolation. The results indicated that the new method is efficiency and can obtain satisfactory results, and is complete in analysis.
Natural Frequency Sensitivities of Lap Joint on Clamped-Clamped Beam
Authors: Yun Seong Ho , Choi Seong Dae , Kim Gi Man
Published: May 2013

This paper deals with the formulation and analysis of dynamic mechanism for joint flexibilities whose relevant magnitudes of stiffnesses are investigated by using linear and torsional springs. The equation of motion is derived by using a generic joint in the middle of clamped-clamped beam. A behavior of natural frequency sensitivities is studied as a function of nondimensional linear and torsional spring stiffnesses.
Mathematical Model and 3D Modeling of Involute Spiral Bevel Gears for Nutation Drive
Authors: Lin Zheng , Yao Li Gang
Published: May 2013

The mathematical model and 3D modeling of involute spiral bevel gears for nutation drive are considered. The basic tooth profile of involute is composed of involute curve and dedendum transition curve, and the equations have been established. The mathematical model of crown gear with involute profile is obtained, and then the mathematical models of the involute spiral bevel gears are developed. The tooth surface modeling of involute spiral bevel gear is proposed, and the 3D modeling of the involute spiral bevel gear for nutation drive is illustrated.
The Design and Strength Calculation of Combination Synchronous Pulley Based on the Overload Protection
Authors: Huang Shu Qin , Li Zheng Feng
Published: May 2013

This paper illustrates two kinds of combination synchronous pulley structure characteristics, the synchronous pulley structure is connected with two parts, the shaft sleeve and the wheel body and the safety pin connects the wheel body and sleeve together. When it appears overload in the process of work, the limit torque will cut the safety pin, then wheel body and shaft sleeve will be separated, in order to protect motor or important part not to be damaged. The two kinds of combination synchronous pulley can be used in different occasions according to its characteristics. This paper introduces the calculation method to design safety pin diameter and the needed materials.
Study of Aerodynamic Drag Reduction on a Compact Electric Vehicle
Authors: Wang Jia , Zhu Hui , Yang Zhi Gang
Published: May 2013

Aerodynamic drag of compact electric vehicles is of significant interest in reducing energy consumption. This study focused on how to reduce drag for a compact electric vehicle by shape optimization such as lengthening the tail, changing the front-windshield inclination, modifying the diffuser angle and filling up the front structure details of the vehicle model. Some separately refined models and one integrated refined model were built. The simulation was conducted using the RANS k-epsilon turbulence model by Computational Fluid Dynamics. The results show that nearly every refined model has a lower drag, and the drag coefficient of the integrated refined model has an 8.4% slash compared to the original vehicle model.
Application and Evaluation of Non-Metallic Pipeline in Lamadian Oilfield
Authors: Zhou Yan Xia , Chen Bin , Li Jin Yu
Published: May 2013

With the characteristics of good corrosion resistance, light weight and long service life, non-metallic pipeline is gradually applied in different areas of oilfield. But its physical and mechanical properties are short comparing to metal pipeline, which limits its promotion in the oilfield. So it is necessary for non-metallic pipeline to evaluate its field application in order to select reasonable pipeline and fully play its anticorrosion performance. Through contrasting and analyzing the field application and laboratory tests of non-metallic pipeline, combining its property and actual production characteristics of Lamadian oilfield, the reasonable application scope can be identified, which can provide technical basis for large area promotion of non-metal pipeline.
Micro Thermal Elastohydrodynamic Lubrication Analysis of Power Law Water-Based Ferrofluid Journal Bearing
Authors: Shi Xiu Jiang , Wang You Qiang
Published: May 2013

Based on the Reynolds equation considering the temperature, the effection of non-newtonian and the magnetic field, the elastohydrodynamic lubrication(EHL) analysis of water-based ferrofluid journal bearing were carried out. The influence of roughness peak height and wavelength on the journal bearing surface with cosine roughness model were analysed. The results reveal that the pressure and film thickness of water-based ferrofluid wave apparently with roughness fluctuation; The fluctuation range of pressure and film thickness increase with the increase of roughness peak height, the minimal film thickness decreases; The pressure and film thickness fluctuation range become more and more sparse with the increase of roughness wavelength, the minimal film thickness increases.
The Research on Numerical Simulation of the Centrifugal Pump and Configuration Perfected
Authors: Ma Yue Jun , Zhao Ji Tao , Yang Yu Min
Published: May 2013

In the paper, on the basis of three-dimensional Reynolds-averaged Navier-Stokes equations and the RNG κ-ε turbulence model, adopting Three-dimensional unstructured grid and pressure connection the implicit correction SIMPLEC algorithm, and using MRF model which is supported by Fluent, this paper carries out numerical simulation of the internal flow of the centrifugal pump in different operation points. According to the results of numerical simulation, this paper analyzes the bad flow phenomena of the centrifugal pump, and puts forward suggests about configuration perfected of the centrifugal pump. In addition, this paper is also predicted the experimental value of the centrifugal pump performance, which is corresponding well with the measured value.
Research on Hydraulic Servo Wobble Board Wave Machine
Authors: Li Yu , Liu Yan Jun , Liu Ji Bin
Published: May 2013

Wave machine is one of the necessary laboratory equipments to optimize the structures and devices in the field of marine engineering. For the purpose of putting forward a new hydraulic servo wobble board wave machine system, we designed the mechanical structure, and carried out the mathematical model of the servo system. The MATLAB analysis result showed that the wave machine was reliable. This research therefore provided fundamental experience for the manufacture of the wave machines and the marine engineering laboratory equipments, and also worked as a reference for the establishment of the other hydraulic servo systems.
The Hydrodynamic Analysis of Hybrid-Driven Underwater Glider
Authors: Xiong Gang , Jiang Jian , Wu Yi Tao , Chen Jun
Published: May 2013

The hybrid-driven underwater glider (HUG) is a new kind of underwater vehicle; it combines the best features of autonomous underwater vehicles and underwater gliders, and can be used as important platforms for marine environment observation and ocean resource exploration. It’s difficult to get the drag coefficient of HUG through theoretical formula. In this paper, we use analysis software Fluent to analyze the HUG with different attack-angle and velocities, get the lift 、 drag coefficient and lift-drag ratio, and determine the biggest lift-drag ratio of HUG in the attack- angle of 6 degrees.
An Energy-Based Similarity Subgrid-Scale Model in Two-Dimensional Planar Shear Flow
Authors: Zhang Yu Xuan , Wu Song Ping
Published: May 2013

A new type of similarity subgrid-scale (SGS) model which based on energy and dissipative scale isotropy assumption is presented. This model combines the advantages of traditional Smagorinsky SGS model with similarity SGS model. And a two-dimensional shear layer flow is simulated using refined grid result as a standard and comparing witch LES method including multiple SGS models. The results indicate that the result of SIM model much approximates to refined grid result than other SGS models.
Analysis and Elimination of Common Faults of Hydraulic System
Authors: Wang Huan Yun , Ma Li , Liu Xiu Fen
Published: May 2013

In order to ensure the normal operation of the hydraulic system, the faults must be found and eliminated promptly and accurately. Most of the faults of hydraulic system don’t happen suddenly. generally, there are signs such as noise, vibration, lash, pollution and leakage etc.. If these phenomena can be found, controlled and eliminated promptly and properly, the system faults can be reduced accordingly. This paper introduces several common faults of hydraulic system and the elimination methods. which the hydraulics technicians can refer to.
Mechanical and Hydraulic Joint Modeling and Simulation about Elec-Pump
Authors: Fu Yong Ling , Li Zhu Feng , Zhang Peng , Chen Huan Ming
Published: May 2013

Elec-pump (electric-hydraulic-pump) is a highly integrated combination of electric motor and hydraulic pump, which has smaller size, lower noise and vibration, better heat elimination, and has broad application prospects. In this paper, an elaborately parameterized model of the axial piston Elec-pump is built for the mechanical and hydraulic joint simulation by using the simulation software AMESim and ADAMS. The joint model is composed of the electromagnetic drive model, hydraulic model, the mechanical dynamics model and the mechanical hydraulic interface. The joint simulation shows how the rotor centroid pulsation affects the output pressure of Elec-pump at different outlet pressures. The results depicts that, due to the rotor centroid pulsation, the outlet pressure pulsation rate becomes more than doubled at the revolution of 7000rev/min.
Numerical Evaluation of Two-Phase Flow in Orthogonal Pipe under High Gravity
Authors: Liu Yi Tao , Song Bao Yin , Yao Qiu Ping
Published: May 2013

In order to follow the technical progress in the filed of aeronautics and astronautics, a numerical investigation into flow characteristic of two-phase flow under high gravity (hi-g) condition is performed. Using the CFD code CFX, the two-phase flow in orthogonal pipe under high gravity condition has been evaluated, and the effects of hi-g on two-phase flow characteristic have been analyzed. Compared with the static condition, the flow pattern, volume fraction, velocity and pressure distributions, pressure drop through the pipe are quite different under hi-g, depending on the magnitude and direction.
Numerical Predictions and Experimental Verifications for Hydrodynamic Performance of Tidal Stream Turbine
Authors: Guo Bin , Wang Da Zheng , Zhou Jun Wei
Published: May 2013

Blade element momentum (BEM) theory is used to design the tidal stream turbine in this paper. ANSYS-CFX and numeca are used to predict the hydrodynamic performance of the turbine. The power coefficient of the turbine obtained by CFD is 39.36% at the design tip speed ratio. A 300mm diameter scale turbine has been built, and the tests were carried out in the circulating water channel, the power coefficient can reach 40.5% at the design tip speed ratio. Through the comparisons between experimental results and CFD results, it proves the application of the numerical method for blade design, and the distributions of the pressure and axial velocity near the blade are analyzed at the end of the paper.
Similarity Laws and Model Test Approaches to Determine Hydrodynamic Performance of a Marine Turbine
Authors: Shi Wei Chao , Wang Da Zheng , Atlar Mehmet , Wang Dan
Published: May 2013

The paper presents the methodologies and approaches used in a Cavitation Tunnel or any other circulation channel to investigate the power extraction performance of a marine stream turbine. The paper first introduced model test similarity laws used in the Emerson Cavitation Tunnel (ECT) of Newcastle University to test a marine turbine in marine propeller cavitation tunnel; then based on these similarity laws to investigate the power extraction performance of a marine turbine in different approaches to control the rotation speed, namely: Torque Control and Rotation-speed control. A comparison was made by the tested experimental results. Torque Control is referred to the speed control strategy of using a generator to absorb the torque building up from the stream, on the other hand Rotation-speed control is to use motor to control rotation speed of the turbine. It indicates that both methods can be employed to investigate the hydro performance of marine stream turbine, with wider range of TSR can Rotation-speed Control test.
Modeling and Its Error Analysis for Load-Sensing Steering System
Authors: Wang Hai Fang , Ren Xiao Guang , Rong Yu
Published: May 2013

Load-sensing hydraulic steering system is universally used in wheeled machinery for good steering regulation performance and obviously saving energy effect. The load-sensing hydraulic steering system is present, and it is considered to be a mechanical and hydraulic position control system. The flow continuity equation and force balance equation of steering system is established, the transfer function of load-sensing hydraulic steering system is obtained, the system steady-state error caused by the typical input signal and load input signal on the basis of transfer function. The main parameters affecting the steady-state error are got, and it provides theoretical support for designing and improvement of load-sensing hydraulic steering system.
Optimization and Flow Analysis of Ducted Tidal Stream Turbine
Authors: Zhou Jun Wei , Wang Da Zheng , Li Ya Nan
Published: May 2013

Efficiency of the tidal stream turbine with thin-wall axisymmetric ducts was numerically simulated. The ducts design parameters of diffuser curves, expansion ratio and duct length were simply optimized. The results showed that the duct of second order diffuser curve, expansion ratio of 2.25 and a length-diameter ratio of 1.2 has the best performance. By comparison of different ducts flow, it revealed that flow separation at the duct outlet and the ejection influenced ducted turbine efficiency. The separation caused blockage and flow rate decreasing, and so performance deteriorated. The ejection caused lower pressure at the outlet of the duct, which allowed higher pressure drop through turbine impeller, and so improved turbine efficiency.
A Temperature Field Model of Complicated Thermal Analysis System Based on Thermal Network Method
Authors: Lin Ze Jin , Yuan Jie Hong , Li Yuan , Yan Xi Jie , Zhou Shi Ming , Chen Run Jing
Published: May 2013

Based on the thermal network method and heat transfer theory, a temperature field simulation model of complicated thermal analysis system was established by Matlab Simulink. Based on the model, a steady-state temperature field of a helicopter tail reducer was calculated in the normal lubrication. The model is more accurate and reliable than the traditional algorithm. Meanwhile, the model can calculate the time-varying process of the temperature field, corresponding to the transient temperature field.
Blow-up of Solutions for a Semi-Linear Heat Equation with Variable Exponents
Authors: Zhang Ji Bing , Gao Yun Zhu
Published: May 2013

In this paper, a semi-linear heat equation with nonlocal boundary condition and variable exponents is studied. The results to existence of global solutions or blow-up of solutions are obtained.
Finite Element Anylasis and Calculate on the Temperature Field of the Thermal Vibration Screen’s Boxes
Authors: Liu Xiao Yan
Published: May 2013

Using the software - ANSYS to analyze the temperature field of the thermal vibration screen after the on-site measurement of the thermal vibration screen's temperature field,the paper have found the highest temperature spot of the side panel and the beams ,which provide the important references for further study on the thermal vibration screen's heat stress and the prediction of working life.
Performance Measure Approach Based Multidisciplinary Design Optimization of Gear Transmission
Authors: Zhang Jun , Zhang Bing
Published: May 2013

In order to reduce the influence of uncertainties on complicated engineering systems performance, a new method is proposed based on the performance measure approach and collaborative optimization (PMA-CO) to implement the reliability-based multidisciplinary design optimization of gear transmission. Both the mathematical model and procedures of PMA-CO are presented. With the adoption of slack factors in the system-level of collaborative optimization, both CO and PMA-CO are applied to the optimization of gear transmission. The proposed PMA-CO improves the reliability of the gear transmission and gained a tradeoff solution between design cost and reliability. Therefore, the PMA-CO is effective and practical in engineering design.
Prognostics and Health Management of Mechanical Systems
Authors: Chang Jiang , Wei Fang
Published: May 2013

Reliability is an important issue to consider for mechanical systems. The state of art is regular checkup and maintenance to ensure normal operations. This is not good enough for safety-critical systems like gearboxes in vehicles and helicopters because the risk of system failure still exists, let alone the manpower and monetary cost required. Prognostics and health management (PHM) was first raised by the U.S. armed force, which should ideally be able to predict faults and schedule maintenance only when necessary by monitoring the system condition. In this paper, inspired by the idea of Built-In Self Test (BIST) in electronic systems, we propose a novel framework to fulfill the task of prognostics and health management with a set of smart sensors, consisting of embedded sensing elements, wireless communication modules and micro-controllers. Both the significance and challenges of the framework are discussed.
Reliability Analysis on Gearbox Transmission System of Agricultural Machinery Chassis Based on FTA
Authors: Zhang Li Xiang , Liu Shou Rong , Li Wei Long , Meng Xin Jia
Published: May 2013

Fault Tree Analysis (FTA) was used to analyze the reliability of gearbox transmission system of 4LZ-2 combine harvester (4LZ-2 CHGTS). Firstly, the structure and function of the 4LZ-2 CHGTS were made a detailed introduction, and the components were divided into three kinds of A, B and C. Secondly, the Fault Tree (FT) model of the 4LZ-2 CHGTS was estabilished using the "top to down" ideology. Finally, based on the FT, the minimal cut sets (MCSs) were given and the weak link of the system was found out by the qualitative analysis; furthermore, the relative probability importance of each basic event and the reliability of the 4LZ-2 CHGTS were analyzed by the quantitative analysis. The results show that the 4LZ-2 CHGTS is of high reliability, and the fault of gears needs to be taken into a key consideration and control in the design process of the GTS.
Analysis of Engine Camshaft Bearing Loosening Fault Based-on Model Simulation and Vibration Signal
Authors: Du Can Yi , Yu Fei Fei
Published: May 2013

Virtual technology is used for simulation analysis of engine camshaft bearing-loosening fault. Firstly, dynamic model of engine powertrain and its valve-train is established, and then the model parameters could be set to simulate the camshaft bearing loosening fault, so the vibration acceleration signals on engine cylinder head can be obtained by simulation calculation. Then by analyzing and comparing with the vibration signals in the normal state, camshaft bearing-loosening fault features are extracted. The analytical result based-on model simulation and vibration signal is used to guide the actual engine fault diagnosis.
Cure-Induced Strain Development in an RTM Epoxy Resin as Monitored by Fiber Bragg Grating Sensors
Authors: Li Xue Qin , Zhang Zi Long , Yi Xiao Su
Published: May 2013

Optimizing the curing temperature to reducing the process costs may influence the properties of the material and bring quality assurance aspects. To solving the problem, real-time strain monitoring of the curing process has become more and more important and urgent. Fiber Bragg grating sensors were successfully used in this work to monitoring the residual strain building-up and the gelling phenomena of an RTM epoxy resin. The results shows chemical shrinkage strain during isothermal curing is bigger for higher curing temperature, but the average linear shrinkage ratio during cooling is smaller.
Fast and High Precision Thermoelectric Potential – Temperature Conversion Method for Aerodynamic Heating Control Systems
Authors: Wu Da Fang , Wu Shuang , Wang Yue Wu , Gao Zhen Tong , Yang Jia Ling
Published: May 2013

A fast and high-precision ‘thermoelectric potential - temperature (E-T)’ sensor conversion method for the transient aerodynamic heating control systems of high-speed aircraft is proposed. The developed method has the advantages of easy calculation, rapid conversion speed and high calibration precision, and can thus be employed for fast non-linear dynamic control of rapidly-changing temperature fields in the aerodynamic heating process of high-speed aircraft.
Fiber Grating Sensor for Hydrogen Detection Using Neural Networks
Authors: Xiao Jie , Qi Wei Min
Published: May 2013

An artificial neural networks modeling (ANNs) for the nanoparticles of palladium (Pd) in the long period fiber Bragg grating (LPFBG) is proposed. A number of simulations have been performed to investigate the characteristics of the proposed approach. The trained and the predicted transmission are compared with the experimental data. The LevenbergMarquardt algorithm has been chosen as the main algorithm because of the lowest mean square error. The model of 20 neurons in two hidden layers shows a better fitting with the experimental data. A new predicted data at 10% H2 concentration has been introduced using proposed ANN model.
Modelling Damage of Composite Laminates with Different Stacking Sequences
Authors: Benbelaid S. , Bezzazi B. , Bezazi A.
Published: May 2013

This paper considers damage development mechanisms in composite laminates subjected to tensile loading. The continuum damage mechanics is the most widely used approach to capture the non linear behaviour of laminates due to cracking. In this study, a continuum damage model based on ply failure criteria, which is initially proposed by Ladevèze has been extended to cover all plies failures mechanisms using an accurate numerical model to predict the equivalent damage accumulation. However, this model requires a reliable representation of the elementary damage mechanisms which can be produced in the composite laminate. To validate this model, a numerical application has been carried on the cross-ply laminates of type [0n/90m]s..A shear lag model was adapted to calculate the average stress of the 0° and 90° plies. The solution presented is obtained by using finite element analysis which implements progressive failure analysis. The effect of the stacking sequences has been done by varying the thickness of the 90° plies.
Characterization of the Surface Quality of Holes Drilled in CFRP Laminates
Authors: Landon Yann , Cherif Mehdi
Published: May 2013

Assembling composite structures requires a significant number of drillings. During machining, defects appear on the surface of the drilled hole. This paper outlines that the criterion Ra is not adapted to reliably characterize the surface quality on composites. In particular, various tests have shown significant variations of the value of Ra according to the angular position of measurement, as well as the filtering artefacts. This study puts forward a new methodology to characterize the surface quality of a composite hole. To this end, a study of sensitivity of the various criteria proposed by standard ISO4287 was conducted. Various geometries of tool are also tested in the experimental phase. The impact of cutting parameters and tool wear are analyzed based on this new methodology.
Inverse Identification Method to Characterize the Behavior of Coupled Elasto-Plastic Coupled to Damage Model Using Modified Erichsen Test
Authors: Nasri Mohamed Toumi , Faouzi Slimani , Ayadi A. , Cherouat Abel , Rezgui Mohamed Ali , Zghal Ali
Published: May 2013

This study presents experimental and numerical approaches to study the thermo-elasto-plastic behavior coupled to ductile damage of thin sheet. The study highlights the influence of temperature on the mechanical properties affecting the ability of forming aluminum sheet 1050A. The properties of the Swifts model hardening coupled to isotropic ductile damage variable and the Erichsen Index are obtained using inverse approach (Nelder-Mead method). The obtained results have established a correlation between the Index Erichsen formability of the material.
Analysis of Instability Plastic Shaping by Hydroforming Thin Sheets at Different Temperatures
Authors: Slimani Faouzi , Cherouat Abel , Ayadi A. , Rezgui Mohammed Ali , Zghal Ali
Published: May 2013

Coupled constitutive equations, formulated in the framework of the thermodynamics of irreversible processes accounting for isotropic hardening as well as the isotropic ductile damage are used to simulate numerically, by the Finite Element Analysis, 3D metal hydroforming processes. The experimental study is dedicated to the identification of stress-strain flow and damage parameters by using the Nelder-Mead simplex algorithm optimization from the global measure of displacement and force. Applications are made to the simulation of thin sheet hydroforming using different at different temperature to show the efficiency of the proposed methodology and to localize plastic instability, thinning of sheet and damage initiation under complex forming conditions.
Chatter Control in Turning Process with a Nonlinear Energy Sink
Authors: Gourc Etienne , Seguy Sébastien , Michon Guilhem , Berlioz Alain
Published: May 2013

This paper presents the interest of an original absorber of vibration in order to reduce chatter vibration in turning process. The device is composed of a linear oscillator corresponding to a flexible cutting tool subject to chatter strongly coupled to a Nonlinear Energy Sink (NES), with purely cubic stiffness. The novelty of this work is the use of a nonlinear cutting law, more accurate for modeling the cutting process. The delayed equations of motion are analyzed using a combination of the method of multiple scales and harmonic balance. Different types of responses regimes are revealed such as periodic response and also Strongly Modulated Response (SMR). Analytic results are then compared with numerical simulations. Finally, the potential of the NES is demonstrated to control chatter in turning process.
A Review on Chemical Synthesis, Characterization and Optical Properties of Nanocrystalline Transition Metal Doped Dilute Magnetic Semiconductors
Authors: Ahmad Tokeer , Khatoon Sarvari , Phul Ruby
Published: May 2013

Nanomaterials have fascinated researchers in recent years because these materials exhibit unusual optical, magnetic and electrical properties as compared to their bulk counterparts. Incorporating impurity ions into a semiconducting host to extend its properties has been one of the most important techniques that paved the way for the modern technology based on spintronic devices. Over the past few years, oxide based dilute magnetic semiconductors (DMSs) have gained remarkable interest due to the possibility of inducing room temperature ferromagnetism. This review describes the experimental developments and optical properties of oxide based DMSs, including the recent results on ZnO, CdO and In2O3 based systems. Optical properties of transition metal (TM)-doped ZnO, CdO and In2O3 dilute magnetic semiconductor nanoparticles show red shift in energy band gaps. Such types of phenomena are attributed to sp-d exchange interactions between band electrons and localized d-electrons of the substituted transition metal ions.
Table of Contents
Antibacterial Effects of Ag, Au and Bimetallic (Ag-Au) Nanoparticles Synthesized from Red Algae
Authors: Ramakritinan C.M. , Kaarunya E. , Shankar Sugandha , Kumaraguru A.K.
Published: May 2013

Recently the utilization of prokaryotic cells (such as bacteria, algae) and plants have emerged as novel methods for the synthesis of nanoparticles intracellularly. Therefore the applications on living organisms have recently attracted the attention of biologists towards nanobiotechnology. In the present study, Silver, Gold and bimetallic alloy Ag-Au nanoparticles were synthesized from marine red alga,Gracilaria sp.,of Gulf of Mannar with different molar concentrations of 100%Ag, 100% Au and Ag:Au (1:1, 1:3 and 3:1). The reduction of Ag, Au and Ag:Au NPs was confirmed by change of colour (i.e. from transparent to dark brown for silver NPs, to ruby red for gold NPs and pale pink for bimetallic NPs) as well as by peak absorption spectra. The absorption peak of theGracilaria sp.,for 100% Ag occurred at 419nm, for 100% Au at 536nm, for Ag: Au (1:1) concentrations at 504 nm for Ag: Au (1:3) at 526 nm and for Ag: Au (3:1) at 501nm. The size of Ag, Au and bimetallic Ag-Au NPs was measured by SEM analysis, proved that the synthesized nanoparticles were colloidal in nature. The bimetallic nanoparticles exhibited good antibacterial activity against Gram positive bacteriaStaphylococcus aureusand Gram negative bacteriaKlebsiella pneumoniae. The above results revealed thatSalmonella typhiiandEscherichia colihave no activity. However, bimetallic NPs of 1:3 concentration showed zones of inhibition against the pathogenic bacteria such asStaphylococcus aureusandKlebsiella pneumoniaerather than Ag NPs and Au NPs. This process of the nanoparticles production is eco-friendly as it is free from any solvent or toxic chemicals, and is also easily amenable for large-scale production.
Inorganic/Organic Hybrid Nanocomposite and its Device Applications
Authors: Tripathi S.K.
Published: May 2013

VI semiconductors are promising nanomaterials for applications as window layers in low-cost and high-efficiency thin film solar cells. These nanoparticles are considered to be the model systems for investigating the unique optical and electronic properties of quantum-confined semiconductors. The electrical and optical properties of polymers are improved by doping with semiconductor materials and metal ions. In particular, nanoparticle-doped polymers are considered to be a new class of organic materials due to their considerable modification of physical properties. In this paper, I review the present status of these types of Inorganic/Organic hybrid nanocomposite materials. CdSe nanorods dispersed in polyvinyl alcohol (PVA) matrix have been prepared by chemical routes. Different characterization techniques like structural, optical and electrical have been used to characterize these nanocomposites. The devices like Schottky diodes and MOS structures have been fabricated and the results have been discussed in this review. The results have been compared with the reported literature by other groups also. Table of Contents
Cell-Autonomous Regulation of Neutrophil Migration by the D6 Chemokine Decoy Receptor
Authors: Rot Antal , McKimmie Clive , Burt Claire L. , Pallas Kenneth J. , Jamieson Thomas , Pruenster Monika , Horuk Richard , Nibbs Robert J. B. , Graham Gerard J.
Published: May 2013

Chemokines, acting on their cognate receptors on infiltrating leukocytes, drive the inflammatory response. We have been interested in determining roles and potential mechanisms for the atypical chemokine-scavenging receptor D6 in the regulation of inflammation. In this study, we show that a psoriasis-like pathology that arises in inflamed skins of D6-deficient mice is characterized by a massive and aberrant localization of neutrophils to the dermal/epidermal junction, which is associated with development of the pathology. Such misplacement of neutrophils is also seen with D6-deficient mice in other inflammatory models, suggesting a role for D6 in the spatial positioning of neutrophils within inflamed sites. We further show that D6 functions cell autonomously in this context and that D6, expressed by neutrophils, limits their migrational responses to CCR1 ligands such as CCL3. Our data therefore indicate that D6 is able to play a cell-autonomous role as a migratory rheostat restricting migration of D6-expressing cells such as neutrophils toward ligands for coexpressed inflammatory chemokine receptors. These data have important implications for our understanding of the roles for D6 in regulating inflammation and for our understanding of the control of spatial positioning of leukocytes at inflamed sites.
« Industries créatives » et « économie créative » : de la conception de notions opératoires au référentiel d’action publique locale
Authors: Le Corf Jean-Baptiste
Published: May 2013

Cet article cherche à saisir l’incorporation des notions d’« industrie créative » et d’« économie créative » dans l’action publique locale. Sont analysées les médiations qui se réalisent au travers de la mobilisation de ces notions, à partir de l’analyse de rapports produits par des organismes internationaux et de l’observation directe de certaines manifestations rassemblant experts et décideurs territoriaux. Puis l’étude porte sur le déploiement d’actions locales en faveur des industries culturelles et créatives et sur les stratégies opportunistes des principaux acteurs engagés dans l’action partenariale : d’une part, les experts intermédiaires en charge de clusters qui défendent les intérêts des acteurs industriels ; d’autre part, les villes cherchant à renouveler leurs politiques de communication.
Regulation of Aedes aegypti Population Dynamics in Field Systems: Quantifying Direct and Delayed Density Dependence
Authors: Walsh Rachael K. , Aguilar Cristobal L. , Facchinelli Luca , Valerio Laura , Ramsey Janine M. , Scott Thomas W. , Lloyd Alun L. , Gould Fred
Published: May 2013

Transgenic strains of Aedes aegypti have been engineered to help control transmission of dengue virus. Although resources have been invested in developing the strains, we lack data on the ecology of mosquitoes that could impact the success of this approach. Although studies of intra-specific competition have been conducted using Ae. aegypti larvae, none of these studies examine mixed age cohorts at densities that occur in the field, with natural nutrient levels. Experiments were conducted in Mexico to determine the impact of direct and delayed density dependence on Ae. aegypti populations. Natural water, food, and larval densities were used to estimate the impacts of density dependence on larval survival, development, and adult body size. Direct and delayed density-dependent factors had a significant impact on larval survival, larval development, and adult body size. These results indicate that control methods attempting to reduce mosquito populations may be counteracted by density-dependent population regulation.
Effect of atmospheric organic complexation on iron-bearing dust solubility
Authors: Paris R. , Desboeufs K. V.
Published: May 2013

Abstract. Recent studies reported that the effect of organic complexation may be a potentially important process to be considered by models estimating atmospheric iron flux to the ocean. In this study, we investigated this process effect by a series of dissolution experiments on iron-bearing dust in the presence or the absence of various organic compounds (acetate, formate, oxalate, malonate, succinate, glutarate, glycolate, lactate, tartrate and humic acid as an analogue of humic like substances, HULIS) typically found in atmospheric waters. Only 4 of tested organic ligands (oxalate, malonate, tartrate and humic acid) caused an enhancement of iron solubility which was associated with an increase of dissolved Fe(II) concentrations. For all of these organic ligands, a positive linear dependence of iron solubility to organic concentrations was observed and showed that the extent of organic complexation on iron solubility decreased in the following order: oxalate >malonate = tartrate > humic acid. This was attributed to the ability of electron donors of organic ligands and implies a reductive ligand-promoted dissolution. This study confirms that among the known atmospheric organic binding ligands of Fe, oxalate is the most effective ligand promoting dust iron solubility and showed, for the first time, the potential effect of HULIS on iron dissolution under atmospheric conditions.
CO2 dispersion modelling over Paris region within the CO2-MEGAPARIS project
Authors: Lac C. , Donnelly R. P. , Masson V. , Pal S. , Riette S. , Donier S. , Queguiner S. , Tanguy G. , Ammoura L. , Xueref-Remy I.
Published: May 2013

Abstract. Accurate simulation of the spatial and temporal variability of tracer mixing ratios over urban areas is a challenging and interesting task needed to be performed in order to utilise CO2 measurements in an atmospheric inverse framework and to better estimate regional CO2 fluxes. This study investigates the ability of a high-resolution model to simulate meteorological and CO2 fields around Paris agglomeration during the March field campaign of the CO2-MEGAPARIS project. The mesoscale atmospheric model Meso-NH, running at 2 km horizontal resolution, is coupled with the Town Energy Balance (TEB) urban canopy scheme and with the Interactions between Soil, Biosphere and Atmosphere CO2-reactive (ISBA-A-gs) surface scheme, allowing a full interaction of CO2 modelling between the surface and the atmosphere. Statistical scores show a good representation of the urban heat island (UHI) with stronger urban–rural contrasts on temperature at night than during the day by up to 7 °C. Boundary layer heights (BLH) have been evaluated on urban, suburban and rural sites during the campaign, and also on a suburban site over 1 yr. The diurnal cycles of the BLH are well captured, especially the onset time of the BLH increase and its growth rate in the morning, which are essential for tall tower CO2 observatories. The main discrepancy is a small negative bias over urban and suburban sites during nighttime (respectively 45 m and 5 m), leading to a few overestimations of nocturnal CO2 mixing ratios at suburban sites and a bias of +5 ppm. The diurnal CO2 cycle is generally well captured for all the sites. At the Eiffel tower, the observed spikes of CO2 maxima occur every morning exactly at the time at which the atmospheric boundary layer (ABL) growth reaches the measurement height. At suburban ground stations, CO2 measurements exhibit maxima at the beginning and at the end of each night, when the ABL is fully contracted, with a strong spatio-temporal variability. A sensitivity test without urban parameterisation removes the UHI and underpredicts nighttime BLH over urban and suburban sites, leading to large overestimation of nocturnal CO2 mixing ratio at the suburban sites (bias of +17 ppm). The agreement between observation and prediction for BLH and CO2 concentrations and urban–rural increments, both day and night, demonstrates the potential of using the urban mesoscale system in the context of inverse modelling
Evaluating and constraining ice cloud parameterizations in CAM5 using aircraft measurements from the SPARTICUS campaign
Authors: Zhang K. , Liu X. , Wang M. , Comstock J. M. , Mitchell D. L. , Mishra S. , Mace G. G.
Published: May 2013

Abstract. This study uses aircraft measurements of relative humidity and ice crystal size distribution collected during the SPARTICUS (Small PARTicles In CirrUS) field campaign to evaluate and constrain ice cloud parameterizations in the Community Atmosphere Model version 5. About 200 h of data were collected during the campaign between January and June 2010, providing the longest aircraft measurements available so far for cirrus clouds in the midlatitudes. The probability density function (PDF) of ice crystal number concentration (Ni) derived from the high-frequency (1 Hz) measurements features a strong dependence on ambient temperature. As temperature decreases from −35 °C to −62 °C, the peak in the PDF shifts from 10–20 L−1 to 200–1000 L−1, while Ni shows a factor of 6–7 increase. Model simulations are performed with two different ice nucleation schemes for pure ice-phase clouds. One of the schemes can reproduce a clear increase of Ni with decreasing temperature by using either an observation-based ice nuclei spectrum or a classical-theory-based spectrum with a relatively low (5–10%) maximum freezing ratio for dust aerosols. The simulation with the other scheme, which assumes a high maximum freezing ratio (100%), shows much weaker temperature dependence of Ni. Simulations are also performed to test empirical parameters related to water vapor deposition and the autoconversion of ice crystals to snow. Results show that a value between 0.05 and 0.1 for the water vapor deposition coefficient, and 250 μm for the critical diameter that distinguishes ice crystals from snow, can produce good agreement between model simulation and the SPARTICUS measurements in terms of Ni and effective radius. The climate impact of perturbing these parameters is also discussed.
Simulation of trace gases and aerosols over the Indian domain: evaluation of the WRF-Chem Model
Authors: Michael M. , Yadav A. , Tripathi S. N. , Kanawade V. P. , Gaur A. , Sadavarte P. , Venkataraman C.
Published: May 2013

Abstract. The "online" meteorological and chemical transport Weather Research and Forecasting/Chemistry (WRF-Chem) model has been implemented over the Indian subcontinent for three consecutive summers in 2008, 2009 and 2010 to study the aerosol properties over the domain. The initial and boundary conditions are obtained from NCAR reanalysis data. The emission rates of sulfur dioxide, black carbon, organic carbon and PM2.5, which are developed over India at a grid resolution of 0.25° × 0.25° have been used in the present study. The remaining emissions are obtained from global inventories (RETRO and EDGAR). The model simulated the meteorological parameters, trace gases and particulate matter. Predicted mixing ratios of trace gases (Ozone, carbon monoxide and sulfur dioxide) are compared with ground based observations over Kanpur. Simulated aerosol optical depth are compared with those observed at nine Aerosol Robotic Network stations (AERONET). The simulations show that the aerosol optical depth of the less polluted regions is better simulated compared to that of the locations where the aerosol loading is very high. The vertical profiles of extinction coefficient observed at Kanpur Micropulse Lidar Network (MPLNET) station is in agreement with the simulated values for altitudes greater than 1.5 km and qualitatively simulate the elevated layers of aerosols. The simulated mass concentration of black carbon shows very good correlation with observations, due to the better local emission inventory used. The vertical profiles of black carbon at various locations have also been compared with observations from aircraft campaign held during pre-monsoon period of 2008 and 2009 resulting in good agreement. This study shows that WRF-Chem model captures many important features of the observations and therefore can be used for understanding and predicting regional atmospheric composition over Indian subcontinent.