bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation Analysis of Boring Finishing Process for a Thermal Power Unit's Valve Body
Authors: Zeng Lin Lin , Zhou Li Ping , Liu Xiao Ying
Published: February 2014

Control valve is the key element for a thermal power unit. As the core component of the valve assembly, the machining quality of valve bodys mating part is an important factor to restrict the performance of valve, so during the machining process, the demands for dimensional accuracy and surface quality of mating surface are quite high. Firstly, set the cutting tool, cutting parameters and other initial conditions according to enterprises actual requirements of body machining. The Deform 3D which is metal cutting finite element software was used to simulate the boring finishing process of mating surface of the valve body, can effectively analyze the changing rule of cutting force and cutting temperature with time. Then, the single factor analysis method was used to analyze the deformation of boring cutter due to cutting force, temperature and abrasion under the condition of different cutting parameters, which influence the quality and precision of valve bodys machining surface. The analysis results obtained in this paper will provide reference for the choice of cutting parameters in the process of actual valve body finish machining.
Finite Element Modeling for the Locomotive Traction Gears
Authors: Shi Xiao Chun , He Wei Dong , Bao Jun Hua
Published: February 2014

In order to improve the bearing capacity and service life of the locomotive traction gears, modern design methods are used to optimize the gear tooth curves and their parameters. The simulation of the involute tooth curves and tooth root transition curves of the traction gears are build by Ansys Parametric Design Language (APDL). It can accurately describe the finite element model with complex geometries. It laid a solid foundation for the tooth strength analysis and modification.
Temperature Field Analysis and Thermal Error Testing for CNC Machine Tool's Headstock
Authors: Zhang Yao Man , Chen Yong , Li Hu
Published: February 2014

The dynamic and thermal characteristics of spindle assembly will affect the final machining performance of a machine tool seriously. It is of great significance to study the dynamic and thermal characteristics of the spindle assembly for improving the level of machine tool's design and manufacturing. The paper takes a high precision computer numerical control lathe as the research object. First the thermal characteristics were obtained by using finite element method. Then the laser triangle measuring instrument and the infrared thermal imager were used to measure the temperature field and thermal deformation of the spindle assembly. Finally in order to get the thermal equilibrium time and the thermal deformation data of spindle system, the wavelet toolbox was used to deal with thermal testing data. The paper's work laid a foundation for the further research on the thermal characteristics analysis and thermal error's compensation of machine tools.
Simulation Analysis of Hydraulic System of Air Tightness Measurement Equipment for Tubeless Wheel Based on Automation Studio
Authors: Xu Peng , Han Jian Yong , Cao He
Published: February 2014

The air tightness measurement equipment for tubeless wheel was introduced and its principle of hydraulic and electrical complex system was analyzed, then the simulation platform was established by Automation Studio software. The work principle and running situation of the system are presented visually and dynamically, which reflects the demand of actual work. In addition, the available tool is offered for failure analysis and technology training by this method.
Study on the Motion Characteristics of a Hydraulic Free-Piston Engine
Authors: Li Shi Yu , Yuan Zhao Cheng , Ma Jia Yi
Published: February 2014

Hydraulic free-piston engines have potential advantages of cost and fuel efficiency. Due to no crankshaft system, it is difficult and important to control the piston motion and working frequency precisely. This paper studies on the motion characteristics for the hydraulic free-piston engine effects of operation parameters, and results are presented. The TDC (Top Dead Center) position and CR (Compression Ration) are great influenced by starting pressure and fuel injection timing, and working frequency is mainly influenced by piston mass, starting pressure and fuel quantity.
Design of a New Type of Soilless Cultivation Vegetable's Barrel
Authors: Zhou Wei Hua
Published: February 2014

According to the characteristics of the traditional soilless cultivation of vegetables and the requirement of its application in the family green vegetable planting, a hanging vegetables planting barrel was designed which has a small footprint and independent rotating function, the speed expression of the barrel was given using the conservation of moment of momentum and momentum theorem, and its influencing factors were discussed also.
Study on Passive Sprinkler Dust Car Underground
Authors: Zhang Jian Zhong , Yang Fei , Zhao Lei
Published: February 2014

This paper introduces a kind of dust removal device-passive sprinkler dust car which is often used to improve the environment and to prevent dust underground. The function, working principle and basic structure of passive sprinkler dust car underground as well as how its main parts work are mainly described in this article. Moreover, the relationship between the spray parameters and the efficiency of reducing dust is studied by adopting the combination of experiment and theoretical analysis methods in order to obtain higher efficiency of reducing dust in this paper.
Thermal Analysis of Desktop Computer Based on Icepak
Authors: Wang Tian , Xu Ping , Cheng Xian
Published: February 2014

Generally, after the desktop computer working very long hours under the high environmental temperature, the components temperature inside the computer chassis would rise. If the temperature of the components was too high to meet the spec, it affected the normal operation of the equipment. Icepak thermal analysis software was adopted for optimized design of the desktop computer system structure, and in the case of not changing the installed position of every component, the internal duct of the computer chassis was designed. The conclusion is known from the simulation results that the design can effectively decrease the components temperature inside the computer and also ensure the stable operation of the equipment.
Kinematics Analysis of the New Type of Offset Radial Piston Motor
Authors: Luo Sheng Mei , Liu Wei , Luo Fu Fang , Yu Wei Wei , Ma Zhi Hong
Published: February 2014

This paper introduces the structural principle of a new offset radial type motor. Through analyzing the kinematic characteristics of the motor piston theory, the result shows that the motor has characteristics of good startup performance at low speed, good sliding performance with sliding boots, smooth operation, low noise and so on, so the performance is superior to the general motor of low speed and high torque. Besides, comparing with other types of hydraulic motor, its lifetime increases and it is also easier to produce and repair. Moreover, beside the use of common hydraulic system, it can also be used in pure water hydraulic system under certain conditions.
Research and Analysis of the CDV Internal-Combustion Engine Gas Distribution Phase in the Low Temperature Start Process
Authors: Shi Lei Ming , Mei Li Ge , Wang Zhi Hong , Shao Yi Ming
Published: February 2014

With the help of CDV internal-combustion engine start process test in the low temperature, it was investigated and analysed for the effects of the intake advance angle of gas distribution phase in the low temperature start and its exhaust-emission performance of internal-combustion engine. In the process of test ,the intake-advance angle change was from 1 °- 11 °and the valve overlap angle change was from 38 ° - 48 °. The internal-combustion engine was started according to the test number of the requirements. It was observed and calculated for starting conditions and exhaust emission with PC. The results show that the appropriate delay of intake valve open timing, and hence the change of valve timing overlap of the intake valve and exhaust valve, and the proper decrease of in-cylinder fresh intake gas, not only significantly improve the performance of internal combustion engine low temperature start combustion work, shortening start duration, but also help to reduce the quantities of HC and CO emissions during the low temperature start process.
Dynamic Analysis for Articulated-Tracked Robot Climbing Stairs
Authors: Rao Wei , Shi Jia Dong , Wang Jian Zhong
Published: February 2014

Climbing stairs is one of the important functions of the articulated-tracked robot obstacle, the robot can be improved through the complex terrain capability. The robot is conducted action planning for climbing stair. Action planning of the robot, speed and acceleration of position change of the robot's center of mass, moment of inertia of driving wheels and arm wheels for influence of the robot dynamic feature are considered, complex dynamic models of the robot to climb stairs are built. The relationships of driving wheel torque, arm wheel torque and its different speed, acceleration, staircases height, angle of the robot and the stairs are analyzed by simulations, maximum driving torques of driving wheel and arm wheel are obtained in the process of robot climbing stairs, a theoretical basis for articulated-tracked robot selecting the appropriate driving torque and motion control are provided.
Experimental Research on Conductor's Ice Accretion and Aerodynamic Characteristics
Authors: Huang Han Jie , Li Xin Min
Published: February 2014

For conductor commonly used in power project, research was conducted on its ice accretion and aerodynamic characteristics. Ice mass and ice shape were examined under various icing condition: time, temperature and wind speed. Ice mass increases linearly with time, while the growth rate varies significantly with wind speed. Ice mass does not increase with the fall of temperature; it reaches the max value in a relatively high temperature range of-5°C~-10°C. Ice shape and ice thickness are both important factors that determine conductors aerodynamic characteristics. Sudden increase of lift coefficient may happen at low attack angle for conductor with thick crescent ice shape.
The Simulation of the Real-Time Adjustment of Cutting Edge Inclination of CNC Turret
Authors: Zhang Shuai , Du Xue Fang
Published: February 2014

In turning process, one of the effective ways to obtain the best cutting characteristics is the real-time adjustment tool cutting edge inclination. This paper designs a real-time adjustment tool cutting edge inclination of the head; the motion analysis by software, the tool structure is optimized further, so that in the premise of turning accuracy, can be adjusted real time tool cutting edge inclination.
Motion Performance Analysis of Deep Water Pipe-Laying Vessel in Regular Wave
Authors: Zan Ying Fei , Dong Zhi Hui , Yuan Li Hao , Wang Ben Tian
Published: February 2014

Based on 3-D potential flow theory, sources and sinks are brought in, distributed upon the wet surface of ship hull. Three-dimensional non-speed frequency domain Green function is also introduced to determine the flow field velocity potential. As a result, added mass, damping coefficient and ship motion response of this deep water pipe-laying vessel are calculated under the regular wave condition. After compared these calculation results to model tank test data, we can see that the theoretical calculation fit well with experimental data. These calculations could provide prediction and guidance for vessel design and marine engineering operation.
Influence Factors Comparison and Analysis of Axial Contact Stiffness between Single-Nut and Double-Nut Ball Screws
Authors: Xu Xiang Rong , Song Xian Chun , Jiang Hong Kui , Li Yan Feng
Published: February 2014

Axial contact stiffness increase of ball screws can reduce the vibration and enhance machining precision of CNC machine tool during machining process. On the basis of Hertz contact theory, calculation formula of axial contact stiffness was deduced with consideration of helix angle for 5010 single-nut and double-nut ball screws, influence factors comparison and analysis was carried out, and contrast curve was obtained. The result shows that the axial contact stiffness of preloaded double-nut ball screws is higher than that of single-nut ball screws. Ball number, contact angle and curvature ratio has obvious influence on the axial contact stiffness of double-nut ball screws: ball number increase can enhance the axial contact stiffness; increase of contact angle and curvature ratio can lower the axial contact stiffness. The axial contact stiffness of single-nut and double-nut ball screws does almost not vary with axial force and helix angle. The conclusion provides certain theoretical basis for design and selection of ball screws.
Using Mathematical Programming Optimization Work Exchange Networks
Authors: Shen Ren Jie , Zhang Wen Wei , Wang Lei
Published: February 2014

For the work exchange network, this paper proposed an optimal matching network mathematical to achieve the maxime reuse target. Based on this method, a case is studied, the corresponding work exchange network is optimized and the optimal matching network is obtained. The case study also shows that this method is more efficient and specific than the graphical and problem table methods, which is proved by the correctness, efficiency and benefits of mathematical programming method.
Analysis of Elements of Large Intercity Bus Operating Conditions Based on Reliability Research
Authors: Yi Jia Xin , Zhang Lu , Li Wen Liang , Zhou Wei
Published: February 2014

The Auto-Proving-Ground test cant reveal all problems of testing vehicles. Establishing a more suitable and accurate test for reliability index of auto-mobiles has become an important issue. The operating states data of coaches that running from Hefei to Zhengzhou has been collected in this paper, principal component analysis, and clustering analysis were then used to obtain the main factors that necessary for researching intercity bus reliability. The road condition, the ratio of idling, acceleration, deceleration and constant velocity has been determined based on the real drive condition. The acceleration in the y direction also has been taken into consideration when the bus steer. Based on the factors we improve the effectiveness and rationality of tests, which is in favor of building the system of rapid detection and evaluation for vehicles reliability.
Design and Application of New Type PCT Measuring System for Hydrogen Storage Alloy
Authors: Guo Zhong Feng , Hu Jun Hong , Xu Liang , Xia Chun Ming
Published: February 2014

In order to analysis the properties of hydrogen storage alloy, hydrogen storage properties, the test principle of pressure-composition-temperature (PCT) was analyzed in detailed, the new type PCT test system was designed on the base of the state equation of ideal gas. The PCT test system is composed of five parts: air supply system, vacuum system, response system, data acquisition system and electric control system. The PCT test system can be carried out in four channel linkage experiments. The hydrogen storage performance experiments of LaNi5 hydrogen storage alloy were carried out by using this system. Hydrogen absorption curve was gained by two kinds of modeling methods. Results show that: the test system can test the hydrogen absorption curve smoothly, efficiently and accurately. The design of this system is reasonable and the test result is reliable.
Research on MWD Mud Pulse Signal Extraction Algorithm
Authors: Zhang Guo Yun , Tu Bing , Zhan Teng Xi
Published: February 2014

The extraction and correct recognition of mud pulse signal in Wireless Measurement While Drilling was a key technology in petroleum drilling process. It determined whether the well course in the petroleum drilling process was right or not. This article has carried out the numerical modeling of mud pulse signal and illustrated its signal feature. In terms of the problems of extraction and recognition of PLM encoded mud pulse signal, it has researched on the noise removing using the Wavelet multi-scale feature recognition and related de-noising algorithms. The location of PLM encoded mud pulse signal was discerned precisely by using the combinational algorithm of local feature and waveform character recognition and laid a foundation for the extraction and accurate recognition of mud pulse signal. Finally, the results of live tests indicate that this arithmetic is simple, useful and conform to the requirements of engineering application.
Analysis of an Air Borne Acoustic Signatures from Welding Process Using Empirical Mode Decomposition
Authors: Yusof M.F.M. , Mahadzir  , Ghazali Mohd Fairusham , Islam Mohd Rafiqul
Published: February 2014

This work present the application of Empirical Mode Decomposition (EMD) to analyze the air borne acoustic signatures commenced during welding process. In order to achieve goals, bead-on plate welding was done onto the carbon steel specimen using Metal Inert Gas Welding. At the same moment, the microphone with operating frequency of 31.5 Hz to 8 kHz used to collect air borne acoustic signatures. In analysis part, Empirical Mode Decomposition has been applied to the acoustic signals and the selected Intrinsic Mode Function (IMF) was presented in frequency-distance plot using spectrogram. Based on the analysis results, there were 3 significant IMF has been found. Those were IMF mode 3, mode 5 and mode 8 which lie within the frequency of 1500 Hz to 4500 Hz, 200 Hz to 800 Hz, and 40 Hz to 80 Hz respectively. The frequency-distance plot from spectrogram of IMF mode 3 showed a significant pattern which can be related with the discontinuity of welding. The discontinuity appears wherever low amplitude power detected in the frequency-distance plot of IMF mode 3. Moreover, the frequency-distance plot of IMF mode 5 and mode 8 can be significantly related with the spatter and weld pool oscillation condition. High power amplitude in frequency-distance plot of IMF mode 8 can indicates the offset of weld pool oscillation frequency and cause the existence of higher amount of spatter which resulting the high power amplitude in frequency-distance plot of IMF mode 5. In summary, it can be conclude that the application of EMD in the analysis of air borne acoustic signatures allow the detection of several phenomena in welding process which might lead to defect once in a time. This was found to be significant in the process of developing the online welding quality monitoring.
Wavelet Based Noise Reduction for Magnetic Anomaly Signal Contaminated by 1/f Noise
Authors: Nie Xin Hua , Pan Zhong Ming , Zhang Wen Na
Published: February 2014

Magnetic anomaly detection is a passive method for detection of a ferromagnetic target, and its performance is often limited by external noise with a power spectral density of 1/fa, (0<a<2). In consideration of this kind of noise is non-stationary, self-similarity and long-range correlation, an effective noise reduction method based on the wavelet transform is proposed in this paper. The proposed method is only take one parameter into account, while the hard thresholding and soft thresholding methods utilize the relationship of the variance of the noisy signal. The simulation results show that the performance of our proposed method is superior to that of other methods.
Design and Application on Bluetooth-Based Wireless Sensor Network Debris Flow Mountain Health Monitoring System
Authors: Ma Hong
Published: February 2014

Based on the Bluetooth technology, using wireless sensor network design the mountain of debris flow health monitoring system, analysied and fixed mountain monitoring elements, given the data acquisition and processing methods, the project is simple, low cost, high reliability . To solve monitoring, early warning, data analysis of the current landslides and debris flow disaster, which are very practical.
Model-Based Design and it's Application in Power Window
Authors: Hu Sheng Hai , Zhang Bao Ping , Sun Tian Shi , Yu Wei
Published: February 2014

Along with the continuous development of embedded systems, embedded products take higher requirements on the scale and performance of system software, and contributing to the complexity of control algorithm. So it would take more time and expense to realize the control algorithm. Therefore, traditional design is out of date and cant cope with the modern development rhythm well. While the Model-Based Design, is an efficient design method to deal with complex embedded control systems. It provides a common development and test platform for the engineers. In this paper, we take the power windows control system as example; establish the algorithm model with the Simulink/Stateflow. Then we introduce these process of the control system design which is based on the Model-Based Design method, according to the result of the final experiment, we prove the efficiency of this method, providing a reference for the design of other complex control systems.
Data Parallel Implementation of Geometric Operations
Authors: Wang Guang
Published: February 2014

The data parallel implementation scheme of zero-order interpolation and first-order interpolation of backward mapping is proved and discussed. It is shown that the complexity of data parallel implementation scheme presented in this paper is Ο(M+N) instead of Ο(MN) in sequential processing, thereby it can easily meet the real time requirements of the digital image processing.
Design of Chirp Signal Based on NIOS
Authors: Zeng Ling Gang , Yang Shou Liang , Mu Xing Xing
Published: February 2014

This paper analyzes the function of chirp. A design solution based on SOPC technology chirp signal put forward after the function had been studied both the hardware design and implement method. The chirp signal generator based on SOPC is designed according to the design process of Matlab/Simulink/DSP Builder/ QuartusII. The generator can produce the chirp signal well which is verified by the Matlab/Simulink and QuartusII. The starting frequency, bandwidth, and frequency resolution of chirp signal can be revamped by utilizing SOPC technology. This method is easier to implement since it is simple to design, easy to modify, low cost, no programming.
Four Bit Priority Resolution Network Using Current Mode Winner Take all Circuit
Authors: Cao Wen Qin , Zhu Hai Yan , Tu Guo Ping
Published: February 2014

This paper presents a new approach for making a four bit priority resolution circuit using current mode winner Take all (WTA) analog computation cells, the winner-takes-all circuit is employed to evaluate the highest input among a set of competing inputs and inhibit the others. This circuit consists of an input stage, a current mode Lazzaros WTA circuit and an output stage consisting of current mirror and load resistor. This circuit is compact, consisting of a total of 28 transistors including the input stage, and a good linearity is observed in response. Simulation of proposed circuit is performed on cadence virtuoso software in 0.18 μm CMOS process technology.
Double-Loop D.C.Speed Regulation System Design Basd on OCC
Authors: Tian Hong Xia , Jiang Pei Lei , Sun Mao Song
Published: February 2014

Elaborated on the method of One Cycle Control (OCC) PWM used on DC speed regulation. The control circuits are designed based on analyses and calculations. Verified by actual debugging, when mathematical model of DC motor is uncertain, the circuits have features such as no speed static error, rapid dynamic response, no need to adjust current loop parameters.
Research of the Giant Magnetostrictive Fule Injector
Authors: Yan Rong Ge , Wang Zhi Juan , Zhu Li Hua
Published: February 2014

This paper studied a giant magnetostrictive fuel injector, which used a giant magnetostrictive actuator as the driving device. The magnetic structure of the giant magnetostrictive fuel injector was designed. The magnetic field of the giant magnetostrictive fuel injector was analyzed by using the finite element method. The total output displacements were computed at various current density levels in driving coil. The results show that the relationship between the input current and the output displacement is approximately linearity. By adjusting the current in driving coil, the output displacement can be linearly controlled, the injector opening size is changed, and then the precise control of stepless fuel flow is realized.
Numerical Simulation on Guide Plates in Coal-Fired Power Plant Flue Pipe Bend with Inner Supports
Authors: Guo Xiao Ke , Geng Ye , Yuan Guo Dong , Yan Bei Bei , Long Zheng Wei , Guo Zhao Jun , Zheng Le Yu
Published: February 2014

At present, power industry is still dominated by coal-fired power generation in China. Coal ash is a major source of air pollution. An important way for controlling atmospheric pollution is reducing dust emission concentration in the coal-fired power plant. Standard curved pipes and guide plates which are widely used in practical application are simulated using computational fluid dynamics (CFD) in this paper. The result shows that inner supports have great impact on flue pipes. Successive bend with guide plates do not have a better flow distribution. These results can provide theoretical basis and method guidance for the design of inner supports.
Constant Value Adjusting Method Based on Characteristic Parameters of Process
Authors: Sun Dian Gang , Liu Zheng Dao , Huang Yong Jian , Zhang Jian Cheng
Published: February 2014

This paper presents a new method to solve the problem of speed and pressure constant value adjustment in the high-power hydraulic pumps and hydraulic motors performance test system which is based on energy recycling technology. The constant value control method is designed based on characteristic parameters of the process, including control resolution, overshoot and adjustment time. Experiments were implemented to verify the effectiveness of the proposed method. Experimental result shows that the proposed method reduced the test time by about 52.4% than before. The convergence rate of the constant value adjusting process and the test efficiency are significantly improved by the proposed method.
Difference Inequalities and Application to Discrete-Time Control Systems
Authors: Hou Zong Yi , Wang Wu Sheng
Published: February 2014

In this paper, two new nonlinear difference inequalities are considered, where the inequalities consist of multiple iterated sums and composite function of nonlinear function and unknown function may be involved in each layer. Under several practical assumptions, the inequalities are solved through rigorous analysis, and explicit bounds for the unknown functions are given clearly. Further, the derived results are applied to the stability problem of a class of linear control systems with nonlinear perturbations.
An Intelligent Control System for LED Headlamp
Authors: Ai Yan Jin , Gao Tie Cheng
Published: February 2014

An intelligent control system for LED headlamp was developed. This system features include two features : LED lamp system of self-adaptive control and use of LED lighting realize visible optical communication. The realization of the control system of intelligent lights include: LED headlights Lord adaptive dimmer, high power LED lamp overheating protection, light and automatic operation, front fog lamps and intelligent control of the lights. Use LED lamp as light lighting equipment, a traditional light it is difficult to have the power to control and adaptive control mode. Based on the optical communication technology LED lighting is using PWM signal of high power LED lamp drivers, control PWM LED lights of empty loading to send the information and than realize the visible optical communication. Optical communication has strong; secrecy is small, transport energy loss of harmless, transmission range, etc.
Simulation and Experimental of Shifting Performance of Construction Machinery
Authors: Ren Feng , Liu Xin Hui , Chen Jin Shi , Zeng Ping , Liu Bo Liang
Published: February 2014

The main objective to study shift buffer impact of shifting process of construction machinery.introduces the working principle of main valve and wet multi-clutch,and developing a mathematical model and AMESim simulation model. analyzes the characteristics of pressure changes during the shift, buffering characteristics and impact on the performance characteristics, and experimental verification. The results showed that: the shift hydraulic system simulation model accurately credible; good performance of the system can effectively reduce shift jerk.
Demonstration of near Field High Energy X-Ray Diffraction Microscopy on High-Z Ceramic Nuclear Fuel Material
Authors: Brown Donald W. , Balogh Levente , Byler Darrin , Hefferan Chris M. , Hunter James F. , Kenesei Peter , Li Shiu Fai , Lind John , Niezgoda Stephen R. , Suter Robert M.
Published: February 2014

Near-field high energy x-ray diffraction microscopy (nf-HEDM) and high energy x-ray micro-tomography (μT) have been utilized to characterize the pore structure and grain morphology in sintered ceramic UO2nuclear fuel material. μT successfully images pores to 2-3μm diameters and is analyzed to produce a pore size distribution. It is apparent that the largest number of pores and pore volume in the sintered ceramic are below the current resolution of the technique, which might be more appropriate to image cracks in the same ceramics. Grain orientation maps of slices determined by nf-HEDM at 25 μm intervals are presented and analyzed in terms of grain boundary misorientation angle. The benefit of these two techniques is that they are non-destructive and thus could be performed before and after processes (such as time at temperature or in-reactor) or even in-situ.
Engineering & Related Studies at J-PARC
Authors: Harjo Stefanus , Aizawa Kazuya , Abe Jun , Gong Wu , Ito Takayoshi , Kawasaki Takuro , Iwahashi Takaaki
Published: February 2014

Current status of a dedicated neutron diffractometer (TAKUMI) for investigations of stresses and crystallographic structures in engineering components, that has been built at Materials and Life Science Facility of J-PARC, was introduced as well as the engineering studies done there. Several topics recently performed at TAKUMI were selected to be introduced; internal strains in an ITER central solenoid conductor sample, internal strains in a rebar embedded in an air-cured concrete, deformation behavior of TRIP steels at RT and tensile behavior of LPSO Mg­Zn­Y alloys. These topics and the relevant results showed that TAKUMI is a powerful neutron diffractometer for various engineering studies.
Crystal Plasticity Finite Element Analysis Based on Crystal Orientation Mapping with Three-Dimensional X-Ray Diffraction Microscopy
Authors: Setoyama Daigo , Hayashi Yujiro , Iwata Noritoshi
Published: February 2014

In other study we examined the plastic behavior for polycrystalline iron by three-dimensional x-ray diffraction (3DXRD) experiment. In this study we analyze the behavior by crystal plasticity finite element (CPFE) analysis, to confirm the validity of application to the deformation analysis of engineering steels of a couple of constitutive models. In the CPFE analysis, the observed microstructure and its crystal orientation are modeled with finite elements to take the inter-granular and intra-granular interactions into consideration. The plastic deformation state of the finite element model was computed by means of CPFE analysis based on the {110}<111> slip system in body centered cubic (BCC) crystal. The experiment showed that the most of the grains rotated toward the preferred orientation <110> along the tensile axis and that intra-granular orientation spread and multi-directionally rotated as the tensile strain increased. These results are reproduced by the CPFE analysis, in which the influence of interaction between neighboring grains is taken into consideration.
Internal Stress Measurement of Weld Part Using Diffraction Spot Trace Method
Authors: Suzuki Kenji , Shobu Takahisa , Shiro Ayumi , Zhang Shuo Yuan
Published: February 2014

The spiral slit-system was improved in order to make a gauge length regularity. The bending stress was measured by the improved spiral slit-system, and the measured stresses corresponded to the applied stress regardless of the diffraction angle. As a result, the validity of the improved spiral slit-system was proved. On the other hand, the diffraction spot trace method (DSTM), which combined the spiral slit-system and a PILATUS detector, was proposed to measure stress in a coarse grain. In this study, the distribution of the residual stress in a melt-run welding specimen was measured using the DSTM. The welding residual stresses measured accorded with that by the FEM simulation.
An Assessment of the Mechanisms of Transformation Plasticity in SA508 Grade 3 Steel during Simulated Welding Thermal Cycles
Authors: Francis John A. , Moat Richard J. , Abdolvand Hamidreza , Forsey Alexander
Published: February 2014

Residual stresses in welded joints must be quantified in order to carry out structural integrity assessments on critical nuclear components. This usually requires the application of finite element models for components with wall thicknesses exceeding 50 mm. In ferritic steels, the development of residual stresses is made more complex by the strains associated with the solid-state phase transformations that occur during heating and cooling. Finite element models often do not account for factors that contribute to anisotropy in the transformation strains, such as Greenwood-Johnson plasticity and variant selection. In this work, we search for evidence that might reveal which mechanism (s) contributes to this anisotropy. Coupons of SA508 steel were subjected to simulated welding thermal cycles, with and without external loading, and in-situ X-ray diffraction was used to track changes in crystal structure. The results were checked for evidence of plastic deformation in austenite and variant selection in its daughter phases.
An Investigation of Residual Stress, Hardness, and Texture on Stress Corrosion Cracking in a Gas Pipeline
Authors: Law Michael , Luzin Vladimir , Linton Valerie , Gamboa Erwin
Published: February 2014

Stress Corrosion Cracking (SCC) may be a serious problem in gas pipelines. This work studies the hardness and residual stress profiles in two nominally identical sections of adjacent pipe with similar environment and coating, one of which was affected by detectable SCC and the other that was not. The results show changes in texture, residual stress, plastic strain, and hardness at the pipe surface which may be responsible for the altered susceptibility to SCC.
Comparison of Synchrotron Radiation Diffraction and Micromagnetic Stress Analysis in Straightened Steel Pipes
Authors: Raatz Sascha , Kaack Michael , Staron Peter , Schell Norbert , Schreyer Andreas , Klaus Manuela , Genzel Christoph , Theis-Bröhl Katharina
Published: February 2014

The use of magnetic Barkhausen noise (MBN) and harmonic analysis (HA) as non-destructiveevaluation (NDE) techniques in the industrial environment increased in the last years. In our study,we evaluated the potential of those methods to measure residual stress on the surface of straightenedsteel pipes. To study the influence of the pipe manufacturing process and the following straighteningprocess we used pipes of three different straightening levels. The straightening was done with differentparameters, which resulted in a plastic deformation that leaves a visible helix on the surface of thepipes. High energy diffraction experiments were performed to obtain absolute values of residual stresson the surface and in the bulk of the pipe samples. With these residual stress values our MBN and HAdata was calibrated. The surface of all pipes showed high compressive stresses while the highest tensilestresses were 0.5 to 1.4 mm under the surface. The stresses correlate to greater plastic deformationduring the straightening process.
Load-Sharing in δ-Processed Inconel 718
Authors: Glavicic Michael , Brown Donald W. , Clausen Bjørn , Sisneros Thomas , Holden Thomas
Published: February 2014

Time-of-flight neutron measurements have been made at 20, 400 and 650oC on δ-processed Inconel 718 in order to measure the load sharing between the γ-phase matrix and the orthorhombic δ-phase. The strain response parallel and perpendicular to the applied stress was measured for seven γ-phase reflections and five δ-phase reflections. The latter were about 50 times weaker than the former suggesting a 2.0% concentration of the δ-phase. At all temperatures the δ-phase strain becomes strongly tensile parallel to the loading direction but also exhibits plastic deformation. However, the nature of the three orthorhombic strains changes with temperature.
Residual Stresses Associated with the Production of Coiled Automotive Springs
Authors: Venter Andrew M. , Luzin Vladimir , Hattingh D.G.
Published: February 2014

Cold coiling of high tensile steel rod into helical coil springs for the automotive industry is a new technique being implemented amongst spring manufacturers worldwide. To characterise this coil production process, the neutron strain scanning technique has been employed to non-destructively elucidate the influence production stages have on the tri-axial residual stress state. Samples investigated represented key production steps in the cold-coil forming process: Cold coiling; Tempering; Hot setting; Hot peening; Shot peening. Investigations revealed that the stress field was axi-symmetrical, that the dominant variation in all samples occurred along the hoop direction (helical circumference), whilst the radial and axial stresses are substantially lower. Accurate two-dimensional stress maps of the rod cross section have been compiled revealing key features associated with the cold coiling step. Comparison of the stress fields after each production step revealed altered stress values. The final shot peening process stage not only reduced stress concentrations at the internal bore, but contributed to the establishment of favourable surface residual stress conditions that enhance the fatigue life of the final product.
Neutron Diffraction Residual Stress Measurements in Electron Beam Welded Compact Tension Specimens
Authors: Kapadia Priyesh , Davies Catrin M. , Pirling Thilo , Dean David W. , Nikbin Kamran M.
Published: February 2014

In a study to investigate the effect of residual stress relaxation on Creep Crack Growth (CCG) a novel fracture mechanics specimen has been designed. Compact Tension, C(T), specimens are fabricated from blocks with Electron Beam (EB) welds such that residual stresses induced during welding are retained in the specimen. Finite element analyses of EB welding and machining processes have been developed to predict the stresses in such C(T) specimens which will drive crack growth in future CCG studies. The residual stresses and strains in these samples have been quantified using the neutron diffraction measurement technique at various stages of the fabrication process and have been used to validate numerical simulations of the fabrication processes.
Psychological Stress in Children May Alter the Immune Response
Authors: Carlsson Emma , Frostell Anneli , Ludvigsson Johnny , Faresjö Maria
Published: February 2014

Psychological stress is a public health issue even in children and has been associated with a number of immunological diseases. The aim of this study was to examine the relationship between psychological stress and immune response in healthy children, with special focus on autoimmunity. In this study, psychological stress was based on a composite measure of stress in the family across the domains: 1) serious life events, 2) parenting stress, 3) lack of social support, and 4) parental worries. PBMCs, collected from 5-y-old high-stressed children (n = 26) and from 5-y-old children without high stress within the family (n = 52), from the All Babies In Southeast Sweden cohort, were stimulated with Ags (tetanus toxoid and β-lactoglobulin) and diabetes-related autoantigens (glutamic acid decarboxylase 65, insulin, heat shock protein 60, and tyrosine phosphatase). Immune markers (cytokines and chemokines), clinical parameters (C-peptide, proinsulin, glucose), and cortisol, as an indicator of stress, were analyzed. Children from families with high psychological stress showed a low spontaneous immune activity (IL-5, IL-10, IL-13, IL-17, CCL2, CCL3, and CXCL10; p < 0.01) but an increased immune response to tetanus toxoid, β-lactoglobulin, and the autoantigens glutamic acid decarboxylase 65, heat shock protein 60, and tyrosine phosphatase (IL-5, IL-6, IL-10, IL-13, IL-17, IFN-γ, TNF-α, CCL2, CCL3, and CXCL10; p < 0.05). Children within the high-stress group showed high level of cortisol, but low level of C-peptide, compared with the control group (p < 0.05). This supports the hypothesis that psychological stress may contribute to an imbalance in the immune response but also to a pathological effect on the insulin-producing β cells.
Three Tapasin Docking Sites in TAP Cooperate To Facilitate Transporter Stabilization and Heterodimerization
Authors: Leonhardt Ralf M. , Abrahimi Parwiz , Mitchell Susan M. , Cresswell Peter
Published: February 2014

The TAP translocates peptide Ags into the lumen of the endoplasmic reticulum for loading onto MHC class I molecules. MHC class I acquires its peptide cargo in the peptide loading complex, an oligomeric complex that the chaperone tapasin organizes by bridging TAP to MHC class I and recruiting accessory molecules such as ERp57 and calreticulin. Three tapasin binding sites on TAP have been described, two of which are located in the N-terminal domains of TAP1 and TAP2. The third binding site is present in the core transmembrane (TM) domain of TAP1 and is used only by the unassembled subunits. Tapasin is required to promote TAP stability, but through which binding site(s) it is acting is unknown. In particular, the role of tapasin binding to the core TM domain of TAP1 single chains is mysterious because this interaction is lost upon TAP2 association. In this study, we map the respective binding site in TAP1 to the polar face of the amphipathic TM helix TM9 and identify key residues that are essential to establish the interaction. We find that this interaction is dispensable for the peptide transport function but essential to achieve full stability of human TAP1. The interaction is also required for proper heterodimerization of the transporter. Based on similar results obtained using TAP mutants that lack tapasin binding to either N-terminal domain, we conclude that all three tapasin-binding sites in TAP cooperate to achieve high transporter stability and efficient heterodimerization.
Unexpected resurgence of a large submersed plant bed in Chesapeake Bay: Analysis of time series data
Authors: Gurbisz Cassie , Kemp W. Michael
Published: February 2014

An historically large (> 50 km2) submersed plant bed in upper Chesapeake Bay virtually disappeared in 1972, following Tropical Storm Agnes. The bed experienced little regrowth until the early 2000s, when plant abundance rapidly increased. Here, we analyze a suite of recent (1984–2010) and historical (1958–1983) time series datasets to assess alternative explanations for the submersed plant resurgence. Change‐point analysis showed that spring nitrogen (N) loading increased from 1945 to 1988 and decreased from 1988 to 2010. Analysis of variance on recent time series showed a significant difference in submersed aquatic vegetation (SAV) abundance percent change during wet years (−7 ± 11%) and dry years (53 ± 20%), indicating that floods and droughts likely contributed to SAV loss and growth, respectively. In the historic dataset, however, increasingly poor water quality led to SAV loss despite an extended drought period, indicating that underlying water quality trends were also important in driving change in SAV abundance. Several water quality variables, including N concentration and turbidity, were lower inside the SAV bed than outside the SAV bed, implying the presence of feedback processes whereby the bed improves its own growing conditions by enhancing biophysical processes such as sediment deposition and nutrient cycling. Together, these analyses suggest that stochastic extremes in river discharge and long‐term water quality trends synergistically facilitated sudden shifts in SAV abundance and that feedback processes likely reinforced the state of the bed before and after the shifts. Management efforts should consider these dynamic interactions and minimize chronic underlying stressors, which are often anthropogenic in origin.
Periodontal Status in Subjects with Hyperlipidemia and Determination of Association between Hyperlipidemia and Periodontal Health: A Clinicobiochemical Study
Authors: Patil Veena A , Desai Manthan H , Shivakumar TP
Published: February 2014

Aim

The aim of this study was to assess the periodontal status in subjects with hyperlipidemia and to determine whether there is any association between hyperlipidemia and periodontitis.

Materials and methods

Sixty subjects with hyperlipidemia and 60 normolipidemic subjects participated in the study. Biochemical parameters assessed included plasma triglyceride, total cholesterol, low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) levels. Periodontal parameters assessed included plaque index (PI), probing depth (PD), clinical attachment level (CAL) and percentage of sites with bleeding on probing (BOP).

Results

Hyperlipidemic patients showed significantly higher values across the four periodontal parameters. Plasma triglycerides, total cholesterol, LDL-C were significantly and positively associated with PD, BOP and CAL (p = 0.05). Whereas HDL-C levels were significantly and negatively associated with PD, BOP and CAL (p = 0.05).

Conclusion

Patients with hyperlipidemia manifested higher values of periodontal parameters compared to control group. Poorly controlled hyperlipidemia had a destructive impact on periodontium. A cyclic relationship exists between serum lipids, periodontitis and systemic health.

Clinical significance

The relationship between periodontium and systemic factors is bidirectional and interlinked. Therefore, dentists and physicians should take this into account while treating patients, aiming for the overall betterment of the patient.

How to cite this article

Shivakumar TP, Patil VA, Desai MH. Periodontal Status in Subjects with Hyperlipidemia and Determination of Association between Hyperlipidemia and Periodontal Health: A Clinicobiochemical Study. J Contemp Dent Pract 2013;14(5):785-789.