WorldWideScience

Sample records for plate thickness variations

  1. GENERALIZED VARIATIONAL PRINCIPLESFOR VISCOELASTIC THIN AND THICK PLATES WITH DAMAGE

    Institute of Scientific and Technical Information of China (English)

    ShengDongfa; ChengChangjun

    2004-01-01

    From the constitutive model with generalized force fields for a viscoelastic body with damage, the differential equations of motion for thin and thick plates with damage are derived under arbitrary boundary conditions. The convolution-type functionals for the bending of viscoelastic thin and thick plates with damage are presented, and the corresponding generalized variational principles are given. From these generalized principles, all the basic equations of the displacement and damage variables and initial and boundary conditions can be deduced. As an example, we compare the difference between the dynamical properties of plates with and without damage and consider the effect of damage on the dynamical properties of plates.

  2. Variations of properties across plate thickness for Al alloy 7010

    Institute of Scientific and Technical Information of China (English)

    M. Salazar-Guapuriche; Y. Y. Zhao; A. Pitman; A. Greene

    2005-01-01

    The variations of electrical conductivity and hardness across the thickness of an Al alloy 7010 plate under the temper condition T7651 were investigated. The electrical conductivity and hardness respond in a reciprocal manner. Cross-sectional slices of the plate subjected to re-solutionising/natural ageing and re-solutionising/artificial ageing show the similar tendencies in property changes as in the as-收稿日期 raw material. This clearly suggests that the property inhomogeneity across the plate thickness is inherent of the manufacturing route. The differences in properties through the plate thickness are due to the changes in the concentrations of the strengthening alloying elements in the solid solution and the associated changes in microstructure;these are believed to be mainly due to the nature of plate solidification and prolonged high temperature during the rolling operation. The combination of electrical conductivity and hardness can be used as an integral quality property indicator for assessing inhomogeneity of thick products.

  3. Transverse Vibrations of Clamped and Simply-Supported Circular Plates with Two Dimensional Thickness Variation

    Directory of Open Access Journals (Sweden)

    N. Bhardwaj

    2012-01-01

    Full Text Available Two dimensional boundary characteristic orthonormal polynomials are used in the Ritz method for the vibration analysis of clamped and simply-supported circular plates of varying thickness. The thickness variation in the radial direction is linear whereas in the circumferential direction the thickness varies according to cos kθ, where k is an integer. In order to verify the validity, convergence and accuracy of the results, comparison studies are made against existing results for the special case of linearly tapered thickness plates. Variations in frequencies for the first six normal modes of vibration and mode shapes for various taper parameters are presented.

  4. Single Transducer Ultrasonic Imaging Method that Eliminates the Effect of Plate Thickness Variation in the Image

    Science.gov (United States)

    Roth, Don J.

    1996-01-01

    This article describes a single transducer ultrasonic imaging method that eliminates the effect of plate thickness variation in the image. The method thus isolates ultrasonic variations due to material microstructure. The use of this method can result in significant cost savings because the ultrasonic image can be interpreted correctly without the need for machining to achieve precise thickness uniformity during nondestructive evaluations of material development. The method is based on measurement of ultrasonic velocity. Images obtained using the thickness-independent methodology are compared with conventional velocity and c-scan echo peak amplitude images for monolithic ceramic (silicon nitride), metal matrix composite and polymer matrix composite materials. It was found that the thickness-independent ultrasonic images reveal and quantify correctly areas of global microstructural (pore and fiber volume fraction) variation due to the elimination of thickness effects. The thickness-independent ultrasonic imaging method described in this article is currently being commercialized under a cooperative agreement between NASA Lewis Research Center and Sonix, Inc.

  5. Variation of strain energy release rate with plate thickness. [fracture mode transition

    Science.gov (United States)

    Sih, G. C.; Hartranft, R. J.

    1973-01-01

    An analytical model of a through-thickness crack in a statically stretched plate is presented in which the crack front stress state is permitted to vary in the direction of the plate thickness. The amplitude or intensity of this stress field can be made nearly constant over a major portion of the interior crack front which is in a state of plane strain. The average amount of work available for extending a small segment of the crack across the thickness is associated with an energy release rate quantity in a manner similar to the two-dimensional Griffith crack model. The theoretically calculated energy release rate is shown to increase with increasing plate thickness, indicating that available work for crack extension is higher in a thicker plate.

  6. Thickness Evaluation of Aluminium Plate Using Pulsed Eddy Current Technique

    Science.gov (United States)

    Singh, Gurpartap; Bapat, Harsh Madhukar; Singh, Bhanu Pratap; Bandyopadhyay, Manojit; Puri, Rakesh Kumar; Badodkar, Deepak Narayanrao

    2013-10-01

    This paper describes a pulsed eddy current (PEC) based non-destructive testing system used for detection of thickness variation in aluminium plate. A giant magneto-resistive sensor has been used instead of pick up coil for detecting resultant magnetic field. The PEC response signals obtained from 1 to 5 mm thickness change in aluminium plate were investigated. Two time domain features, namely peak value and time to peak, of PEC response were used for extracting information about thickness variation in aluminium plate. The variation of peak value and time to peak with thickness was compared. A program was developed to display the thickness variation of the tested sample.

  7. A Comparison of Vibroacoustic Response of Isotropic Plate with Attached Discrete Patches and Point Masses Having Different Thickness Variation with Different Taper Ratios

    Directory of Open Access Journals (Sweden)

    Bipin Kumar

    2016-01-01

    Full Text Available A comparison of sound radiation behavior of plate in air medium with attached discrete patches/point masses having different thickness variations with different taper ratio of 0.3, 0.6, and 0.9 is analysed. Finite element method is used to find the vibration characteristics while Rayleigh integral is used to predict the sound radiation characteristics. Minimum peak sound power level obtained is at a taper ratio of 0.6 with parabolic increasing-decreasing thickness variation for plate with four discrete patches. At higher taper ratio, linearly increasing-decreasing thickness variation is another alternative for minimum peak sound power level suppression with discrete patches. It is found that, in low frequency range, average radiation efficiency remains almost the same, but near first peak, four patches or four point masses cause increase in average radiation efficiency; that is, redistribution of point masses/patches does have effect on average radiation efficiency at a given taper ratio.

  8. Free vibration analysis of Mindlin plates with linearly varying thickness

    Science.gov (United States)

    Aksu, G.; Al-Kaabi, S. A.

    1987-12-01

    A method based on the variational principles in conjunction with the finite difference technique is applied to examine the free vibration characteristics of isotropic rectangular plates of linearly varying thickness by including the effects of transverse shear deformation and rotary inertia. The validity of the present approach is demonstrated by comparing the results with other solutions proposed for plates with uniform and linearly varying thickness. Natural frequencies and mode shapes of Mindlin plates with simply supported and clamped edges are determined for various values of relative thickness ratio and the taper thickness constant.

  9. Crustal thickness controlled by plate tectonics

    DEFF Research Database (Denmark)

    Artemieva, Irina M.; Meissner, Rolf

    2012-01-01

    /gabbro–eclogite phase transition in crustal evolution and the links between lithosphere recycling, mafic magmatism, and crustal underplating. We advocate that plate tectonics processes, togetherwith basalt/gabbro–eclogite transition, limit crustal thickness worldwide by providing effective mechanisms of crustal...... (lithosphere) recycling. The processes of crust–mantle interaction have created very dissimilar crustal styles in Europe, as seen by its seismic structure, crustal thickness, and average seismic velocities in the basement. Our special focus is on processes responsible for the formation of the thin crust...

  10. Development of plating thickness standards. Milestone report

    Energy Technology Data Exchange (ETDEWEB)

    Russell, R.J.

    1978-01-01

    Standards which are unavailable from the National Bureau of Standards were developed to support the nondestructive measurement of plating thickness. Their fabrication, measurement, certification, and calibration-recall schedule are discussed. Reference standards that have been put into service include aluminum/Kapton, silver/copper, tin/steel, gold/silver, cadmium/Kovar, silver/iron, rhodium/copper, and gold/ceramic. 6 figures, 3 tables.

  11. Crustal thickness controlled by plate tectonics

    DEFF Research Database (Denmark)

    Artemieva, Irina M.; Meissner, Rolf

    2012-01-01

    The continental crust on Earth cannot be extracted directly from the mantle, and the primary crust extracted directly from an early magma ocean is not preserved on Earth. We review geophysical and geochemical aspects of global crust–mantle material exchange processes and examine the processes which...... magmatism. While both subduction and delamination recycle crustal material into the mantle, mafic magmatism transports mantle material upward and participates in growth of newoceanic and continental crusts and significant structural and chemicalmodification of the latter. We discuss the role of basalt....../gabbro–eclogite phase transition in crustal evolution and the links between lithosphere recycling, mafic magmatism, and crustal underplating. We advocate that plate tectonics processes, togetherwith basalt/gabbro–eclogite transition, limit crustal thickness worldwide by providing effective mechanisms of crustal...

  12. Measurement of thickness profiles of glass plates by analyzing Haidinger fringes.

    Science.gov (United States)

    Park, Ju Eun; Kim, Jiung; Cha, Myoungsik

    2017-03-01

    We report what we believe is a novel method for measuring the thickness profiles of plane parallel plates by analyzing their Haidinger fringes. When an extended monochromatic source is viewed through a ∼1-mm-thick plate, concentric transmission-type Haidinger fringes can easily be observed. Small variations in the plate thickness result in changes in the radii of the ring fringes. In this study, we scanned 20-mm-diameter fused silica and BK7 plates while tracing a specific ring in each fringe pattern to measure the thickness profiles of the plates, achieving an uncertainty of 2 nm in the measurements of the thickness differences between two locations on each plate.

  13. Energy trapping of thickness-shear vibration modes of elastic plates with functionally graded materials.

    Science.gov (United States)

    Wang, Ji; Yang, Jiashi; Li, Jiangyu

    2007-03-01

    Energy trapping has important applications in the design of thickness-shear resonators. Considerable efforts have been made for the effective utilization and improvement of energy trapping with variations of plate configurations, such as adding electrodes and contouring. As a new approach in seeking improved energy trapping feature, we analyze thickness-shear vibrations in an elastic plate with functionally graded material (FGM) of in-plane variation of mechanical properties, such as elastic constants and density. A simple and general equation governing the thickness-shear modes is derived from a variational analysis. A plate with piecewise constant material properties is analyzed as an example. It is shown that such a plate can support thickness-shear vibration modes with obvious energy trapping. Bechmann's number for the existence of only one trapped mode also can be determined accordingly.

  14. A study of microclad thickness variation (1987)

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, R.S.; Armstrong, K.P.

    1989-06-22

    A study was conducted to investigate the thickness variation of microclad material used in fabricating 1E38 bridges. For the role sampled (nine reels), standard deviations within reels ranged from 6.11 to 12.07 {mu}in. Thickness variations within reels ranged from 16.2 to 40.9 {mu}in., with the average thickness between 142.90 and 161.28 {mu}in.

  15. A spectroscopic method for determining thickness of quartz wave plate

    Institute of Scientific and Technical Information of China (English)

    Weiwei Feng; Lihuang Lin; Ligang Chen; Huafeng Zhu; Ruxin Li; Zhizhan Xu

    2006-01-01

    A spectroscopic method to determine thickness of quartz wave plate is presented. The method is based on chromatic polarization interferometry. With the polarization-resolved transmission spectrum (PRTS)curve, the phase retardation of quartz wave plate can be determined at a wide spectral range from 200 to2000 nm obviously. Through accurate judgment of extreme points of PRTS curve at long-wave band, the physical thickness of quartz wave plates can be obtained exactly. We give a measuring example and the error analysis. It is found that the measuring precision of thickness is mainly determined by the spectral resolution of spectrometer.

  16. Numerical Controlled Rolling Process of Thick Metal Plate

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Thick metal plate rolling process has become more and more important in building a flat roof of drilling on the bottom at sea. This is because not only the product quality requirement higher and higher but also the marketing competition. To improve the process of thick metal plate rolling and to increase productivity a numerical controlled rolling process is developed, which include the process planning, the mathematical model establishment and the numerical control system development. The process is for ...

  17. Transient motion of thick anisotropic plates

    Science.gov (United States)

    Nayfeh, Adnan H.; Taylor, Timothy W.

    1991-01-01

    Analyses are developed for the response of anisotropic plate strips to a transient load. The load is taken in the form of a line load of normal stress on the surface or within the body of the strip. The characteristic free vibrational modes of the strip are derived and used to derive the secular equation for this case in closed form and to isolate the mathematical conditions for symmetric and antisymmetric wave mode propagation in completely separate terms. The applied loads are expanded in terms of these normal modes and the response of the plate is obtained by superposition of the appropriate components. Material systems of higher symmetry are contained implicitly in the analysis.

  18. CRUSTAL THICKNESS VARIATIONS AND SEISMICITY OF NORTHWESTERN SOUTH AMERICA

    Directory of Open Access Journals (Sweden)

    Woo Kim Jeong

    2007-06-01

    Full Text Available Any uncompensated mass of the northern Andes Mountains is presumably under pressure to adjust within the Earth to its ideal state of isostatic equilibrium. Isostasy is the ideal state that any
    uncompensated mass seeks to achieve in time. These pressures interact with the relative motions between adjacent plates that give rise to earthquakes along the plate boundaries. By combining the
    gravity MOHO estimates and crustal discontinuities with historical and instrumental seismological catalogs the correlation between isostatically disturbed terrains and seismicity has been established.
    The thinner and thicker crustal regions were mapped from the zero horizontal curvature of the crustal thickness estimates. These boundaries or edges of crustal thickness variations were compared to
    crustal discontinuities inferred from gravity and magnetic anomalies and the patterns of seismicity that have been catalogued for the last 363 years. The seismicity is very intense along the Nazca-North
    Andes, Caribbean-North American and North Andes-South American collision zones and associated with regional tectonic compressional stresses that have locally increased and/or diminished by
    compressional and tensional stress, respectively, due to crustal thickness variations. High seismicity is also associated with the Nazca-Cocos diverging plate boundary whereas low seismicity is associated with the Panama-Nazca Transform Fault and the South American Plate.

  19. Stress measurement in thick plates using nonlinear ultrasonics

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, Zeynab, E-mail: zabbas5@uic.edu, E-mail: dozevin@uic.edu; Ozevin, Didem, E-mail: zabbas5@uic.edu, E-mail: dozevin@uic.edu [University of Illinois at Chicago, Civil and Materials Engineering, 842 W Taylor Street ERF 2095, Chicago, IL 60607 (United States)

    2015-03-31

    In this paper the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded thick steel plates using fundamental theory of nonlinear ultrasonics is investigated in order to measure the stress state at a given cross section. The measurement concept is based on phased array placement of ultrasonic transmitter-receiver to scan three angles of a given cross section using Rayleigh waves. The change in the ultrasonic data in thick steel plates is influenced by normal and shear stresses; therefore, three measurements are needed to solve the equations simultaneously. Different thickness plates are studied in order to understand the interaction of Rayleigh wave penetration depth and shear stress. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The influences of plate thickness and ultrasonic frequency on the identification of stress tensor are numerically studied in 3D structural geometry and Murnaghan material model. The experimental component of this study includes uniaxial loading of the plate while measuring ultrasonic wave at three directions (perpendicular, parallel and angled to the loading direction). Instead of rotating transmitter-receiver pair for each test, a device capable of measuring the three angles is designed.

  20. Stress measurement in thick plates using nonlinear ultrasonics

    Science.gov (United States)

    Abbasi, Zeynab; Ozevin, Didem

    2015-03-01

    In this paper the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded thick steel plates using fundamental theory of nonlinear ultrasonics is investigated in order to measure the stress state at a given cross section. The measurement concept is based on phased array placement of ultrasonic transmitter-receiver to scan three angles of a given cross section using Rayleigh waves. The change in the ultrasonic data in thick steel plates is influenced by normal and shear stresses; therefore, three measurements are needed to solve the equations simultaneously. Different thickness plates are studied in order to understand the interaction of Rayleigh wave penetration depth and shear stress. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The influences of plate thickness and ultrasonic frequency on the identification of stress tensor are numerically studied in 3D structural geometry and Murnaghan material model. The experimental component of this study includes uniaxial loading of the plate while measuring ultrasonic wave at three directions (perpendicular, parallel and angled to the loading direction). Instead of rotating transmitter-receiver pair for each test, a device capable of measuring the three angles is designed.

  1. Oblique perforation of thick metallic plates by rigid projectiles

    Institute of Scientific and Technical Information of China (English)

    Xiaowei Chen; Qingming Li; Saucheong Fan

    2006-01-01

    Oblique perforation of thick metallic plates by rigid Drojectiles with various nose shapes is studied in this paper.Two perforation mechanisms,i.e., the hole enlargement for a sharp projectile nose and the plugging formation for a blunt projectile nose,are considered in the proposed analytical model.It is shown that the perforation of a thick plate is dominated by several non-dimensional numbers,i.e., the impact function,the geometry function of projectile,the non-dimensional thickness of target and the impact obliquity.Explicit formulae are obtained to predict the ballistic limit.residual velocity and directional change for the oblique perforation of thick metallic plates.The proposed model is able to predict the critical condition for the occurrence of ricochet.The proposed model is validated by comparing the predictions with other existing models and independent experimental data.

  2. High-accuracy thickness measurement of a transparent plate with the heterodyne central fringe identification technique

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wang-Tsung; Hsieh, Hung-Chih; Chang, Wei-Yao; Chen, Yen-Liang; Su, Der-Chin

    2011-07-20

    In a modified Twyman-Green interferometer, the optical path variation is measured with the heterodyne central fringe identification technique, as the light beam is focused by a displaced microscopic objective on the front/rear surface of the test transparent plate. The optical path length variation is then measured similarly after the test plate is removed. The geometrical thickness of the test plate can be calculated under the consideration of dispersion effect. This method has a wide measurable range and a high accuracy in the measurable range.

  3. Through-thickness inhomogeneity of localized corrosion in 7050-T7451 Al alloy thick plate

    Institute of Scientific and Technical Information of China (English)

    丰雷; 潘清林; 韦莉莉; 黄志其; 刘志铭

    2015-01-01

    The through-thickness corrosion inhomogeneity of 7050-T7451 Al alloy thick plate was studied using immersion tests, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), slow strain rate testing (SSRT) technique combined with optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the through-thickness corrosion resistance is ranked in the order of T/2>surface>T/4. And the 75 mm-thick 7050 alloy plate presents better corrosion resistance than the 35 mm-thick plate. The results are discussed in terms of the combined effect of recrystallization and cooling rate in quenching. Alloy with lower volume fraction of recrystallization and smaller grain aspect ratio displays better corrosion resistance. The lower corrosion resistance caused by the slower cooling rate results from the higher coverage rate of grain boundary precipitates and larger width of precipitate free zone.

  4. Residual stress in quenched 7075 aluminum alloy thick plates

    Institute of Scientific and Technical Information of China (English)

    林高用; 张辉; 朱伟; 彭大暑; 梁轩; 周鸿章

    2003-01-01

    The influence of quenching water temperature, pre-stretching amount and aging temperature and times on residual stress in 7075 aluminum thick plate was studied by the measurement of residual stress using drilling hole method. The results indicate that residual stress decreases by 30% with increasing quenching water temperature from 40 ℃ to 80 ℃, 20% with increasing aging temperature from 100 ℃ to 180 ℃,and 20% with increasing aging times from 5 h to 25 h. Also, residual stress decreases to zero with increasing pre-stretching amount to approximately 2%. Hence, residual stress in 7075 aluminum thick plate is reduced by the control of quenching water temperature at 80 ℃ and with pre-stretching amount of about 2%. An optimal aging temperature and time should be systemically investigated to obtain combination of high mechanical performances and lower residual stress for manufacturing of 7075 aluminum alloy thick plates.

  5. A new refined theory of plates with transverse shear deformation for moderately thick and thick plates

    CERN Document Server

    Valle, Jose Miguel Martinez

    2015-01-01

    In this paper we propose a new refined shear deformation plate theory which possesses a series of desirable features, the most salient of which are as follows: (i) The loads, which are generally considered to be applied on the middle surface of the plate, act on the upper surface of the plate; (ii) The equations are applicable to the calculation of the stresses in isotropic plates and provide the same order of accuracy as several theories with second order shear deformation effects; (iii) It constitutes a theory, in the sense defined by Love, since it gives easy expressions for application to problems in different fields in architecture and civil engineering

  6. Sound radiation from a joint of plates of different thickness

    Science.gov (United States)

    Kirpichnikov, V. Yu.; Romanova, V. V.

    2003-09-01

    A method of solving the problem of sound radiation from a plate with elements of different thickness in its plane is proposed, and the results obtained with this method are presented. It is shown that the main sources of sound radiation are the inhomogeneous flexural fields formed in the elements on both sides of their joint.

  7. Minimum Plate Thickness in High-Speed Craft

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    The minimum plate thickness requirements specified by the classification societies for high-speed craft are supposed to ensure adequate resistance to impact loads such as collision with floating objects and objects falling on the deck. The paper presents analytical methods of describing such impact...

  8. ELASTIC DYNAMIC ANALYSIS OF MODERATELY THICK PLATE USING MESHLESS LRPIM

    Institute of Scientific and Technical Information of China (English)

    Ping Xia; Shuyao Long; Hongxue Cui

    2009-01-01

    A meshless local radial point interpolation method (LRPIM) for solving elastic dy-namic problems of moderately thick plates is presented in this paper. The discretized system equation of the plate is obtained using a locally weighted residual method. It uses a radial basis function (RBF) coupled with a polynomial basis function as a trial function, and uses the quartic spline function as a test function of the weighted residual method. The shape function has the properties of the Kronecker delta function, and no additional treatment is done to impose essen-tial boundary conditions. The Newmark method for solving the dynamic problem is adopted in computation. Effects of sizes of the quadrature sub-domain and influence domain on the dynamic properties are investigated. The numerical results show that the presented method can give quite accurate results for the elastic dynamic problem of the moderately thick plate.

  9. NONLINEAR VIBRATION FOR MODERATE THICKNESS RECTANGULAR CRACKED PLATES INCLUDING COUPLED EFFECT OF ELASTIC FOUNDATION

    Institute of Scientific and Technical Information of China (English)

    XIAO Yong-gang; FU Yi-ming; ZHA Xu-dong

    2005-01-01

    Based on Reissner plate theory and Hamilton variational principle, the nonlinear equations of motion were derived for the moderate thickness rectangular plates with transverse surface penetrating crack on the two-parameter foundation. Under the condition of free boundary, a set of trial functions satisfying all boundary conditions and crack's continuous conditions were proposed. By employing the Galerkin method and the harmonic balance method, the nonlinear vibration equations were solved and the nonlinear vibration behaviors of the plate were analyzed. In numerical computation, the effects of the different location and depth of crack, the different structural parameters of plates and the different physical parameters of foundation on the nonlinear amplitude frequency response curves of the plate were discussed.

  10. Analysis of Shrinkage on Thick Plate Part using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Najihah S.N.

    2016-01-01

    Full Text Available Injection moulding is the most widely used processes in manufacturing plastic products. Since the quality of injection improves plastic parts are mostly influenced by process conditions, the method to determine the optimum process conditions becomes the key to improving the part quality. This paper presents a systematic methodology to analyse the shrinkage of the thick plate part during the injection moulding process. Genetic Algorithm (GA method was proposed to optimise the process parameters that would result in optimal solutions of optimisation goals. Using the GA, the shrinkage of the thick plate part was improved by 39.1% in parallel direction and 17.21% in the normal direction of melt flow.

  11. High-precision Thickness Setting Models for Titanium Alloy Plate Cold Rolling without Tension

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaochen; YANG Quan; HE Fei; SUN Youzhao; XIAO Huifang

    2015-01-01

    Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

  12. High-precision thickness setting models for titanium alloy plate cold rolling without tension

    Science.gov (United States)

    Wang, Xiaochen; Yang, Quan; He, Fei; Sun, Youzhao; Xiao, Huifang

    2015-03-01

    Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

  13. Incremental ECAP of thick continuous plates - machine and initial trials

    Science.gov (United States)

    Rosochowski, A.; Olejnik, L.

    2014-08-01

    Incremental ECAP (I-ECAP) can be used for SPD of continuous bars, plates and sheets. This paper describes design, construction and preliminary trials of a prototype machine capable of processing thick continuous plates. To increase productivity, a two-turn I-ECAP is used, which is equivalent to route C in conventional one-turn ECAP. The machine has a reciprocating punch inclined at 45°, a clamp holding the plate in the die during deformation and a feeder incrementally feeding the plate when it is not deformed; all these devices are driven by hydraulic actuators controlled by a PLC. The machine is capable of deforming materials at room temperature as well as elevated temperatures. The die is heated with electric heaters. The machine has also an integrated cooling system and a lubrication system. The material used for the initial trials was Al 1050 plate (10×50×1000) conversion coated with calcium aluminate and lubricated with dry soap. The process was carried out at room temperature using 1.6 mm feeding stroke and a low cycle frequency of approximately 0.2 Hz. The UFG structure after the first pass of the process revealed by STEM confirms process feasibility.

  14. Crustal-thickness variations in the central Andes

    Science.gov (United States)

    Beck, Susan L.; Zandt, George; Myers, Stephen C.; Wallace, Terry C.; Silver, Paul G.; Drake, Lawrence

    1996-05-01

    We estimated the crustal thickness along an east-west transect across the Andes at lat 20°S and along a north-south transect along the eastern edge of the Altiplano from data recorded on two arrays of portable broadband seismic stations (BANJO and SEDA). Waveforms of deep regional events in the downgoing Nazca slab and teleseismic earthquakes were processed to isolate the P-to-S converted phases from the Moho in order to compute the crustal thickness. We found crustal-thickness variations of nearly 40 km across the Andes. Maximum crustal thicknesses of 70 74 km under the Western Cordillera and the Eastern Cordillera thin to 32 38 km 200 km east of the Andes in the Chaco Plain. The central Altiplano at 20°S has crustal thicknesses of 60 to 65 km. The crust also appears to thicken from north (16°S, 55 60 km) to south (20°S, 70 74 km) along the Eastern Cordillera. The Subandean zone crust has intermediate thicknesses of 43 to 47 km. Crustal-thickness predictions for the Andes based on Airy-type isostatic behavior show remarkable overall correlation with observed crustal thickness in the regions of high elevation. In contrast, at the boundary between the Eastern Cordillera and the Subandean zone and in the Chaco Plain, the crust is thinner than predicted, suggesting that the crust in these regions is supported in part by the flexural rigidity of a strong lithosphere. With additional constraints, we conclude that the observation of Airy-type isostasy is consistent with thickening associated with compressional shortening of a weak lithosphere squeezed between the stronger lithosphere of the subducting Nazca plate and the cratonic lithosphere of the Brazilian craton.

  15. Effects of plate thickness on reverse martensitic transformation of prestrained NiTi/NiTi alloy

    Institute of Scientific and Technical Information of China (English)

    YAN Zhu; CUI Lishan; ZHENG Yanjun

    2007-01-01

    In this Paper, differential scanning calorimeter (DSC)was used to study the effects of predeformation and plate thickness on the reverse martensitic transformation of explosively welded NiTi/NiTi alloy.Results showed that there was a constraint between Ni50.4Ti(NiTi-1)and Ni49.8Ti (NiTi-2),which led to that the thickness of NiTi-1 or NiTi-2 strongly affected the reverse martensitic transformation behavior because residual stress variations in thickness wound enable bias force to be built inside the composite.The DSC measurements showed that after deformation,the reverse martensitic transformation temperature of the composite was increased with the increasing thickness of NiTi-2.Also.the XRD results revealed that the microstructure of NiTi/NiTi alloy changed from B2 phase to B19'phase along the thickness direction.

  16. Thin elastic shells with variable thickness for lithospheric flexure of one-plate planets

    CERN Document Server

    Beuthe, Mikael

    2007-01-01

    Planetary topography can either be modeled as a load supported by the lithosphere, or as a dynamical effect due to lithospheric flexure caused by mantle convection. In both cases the response of the lithosphere to external forces can be calculated with the theory of thin elastic plates or shells. On one-plate planets the spherical geometry of the lithospheric shell plays an important role in the flexure mechanism. So far the equations governing the deformations and stresses of a spherical shell have only been derived under the assumption of a shell of constant thickness. However local studies of gravity and topography data suggest large variations in the thickness of the lithosphere. In this article we obtain the scalar flexure equations governing the deformations of a thin spherical shell with variable thickness or variable Young's modulus. The resulting equations can be solved in succession, except for a system of two simultaneous equations, the solutions of which are the transverse deflection and an associ...

  17. Changes in Flat Plate Wake Characteristics Obtained With Decreasing Plate Thickness

    Science.gov (United States)

    Rai, Man Mohan

    2016-01-01

    The near and very near wake of a flat plate with a circular trailing edge is investigated with data from direct numerical simulations. Computations were performed for four different Reynolds numbers based on plate thickness (D) and at constant plate length. The value of ?/D varies by a factor of approximately 20 in the computations (? being the boundary layer momentum thickness at the trailing edge). The separating boundary layers are turbulent in all the cases. One objective of the study is to understand the changes in wake characteristics as the plate thickness is reduced (increasing ?/D). Vortex shedding is vigorous in the low ?/D cases with a substantial decrease in shedding intensity in the largest ?/D case (for all practical purposes shedding becomes almost intermittent). Other characteristics that are significantly altered with increasing ?/D are the roll-up of the detached shear layers and the magnitude of fluctuations in shedding period. These effects are explored in depth. The effects of changing ?/D on the distributions of the time-averaged, near-wake velocity statistics are discussed.

  18. Effect of Glass Thickness on Performance of Flat Plate Solar Collectors for Fruits Drying

    Directory of Open Access Journals (Sweden)

    Ramadhani Bakari

    2014-01-01

    Full Text Available This study aimed at investigating the effect of thickness of glazing material on the performance of flat plate solar collectors. Performance of solar collector is affected by glaze transmittance, absorptance, and reflectance which results into major heat losses in the system. Four solar collector models with different glass thicknesses were designed, constructed, and experimentally tested for their performances. Collectors were both oriented to northsouth direction and tilted to an angle of 10° with the ground toward north direction. The area of each collector model was 0.72 m2 with a depth of 0.15 m. Low iron (extra clear glass of thicknesses 3 mm, 4 mm, 5 mm, and 6 mm was used as glazing materials. As a control, all collector performances were analysed and compared using a glass of 5 mm thickness and then with glass of different thickness. The results showed that change in glass thickness results into variation in collector efficiency. Collector with 4 mm glass thick gave the best efficiency of 35.4% compared to 27.8% for 6 mm glass thick. However, the use of glass of 4 mm thick needs precautions in handling and during placement to the collector to avoid extra costs due to breakage.

  19. UNSYMMETRICAL NONLINEAR BENDING PROBLEM OF CIRCULAR THIN PLATE WITH VARIABLE THICKNESS

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-zhi; ZHAO Yong-gang; JU Xu; ZHAO Yan-ying; YEH Kai-yuan

    2005-01-01

    Firstly, the cross large deflection equation of circular thin plate with variable thickness in rectangular coordinates system was transformed into unsymmetrical large deflection equation of circular thin plate with variable thickness in polar coordinates system.This cross equation in polar coordinates system is united with radical and tangential equations in polar coordinates system, and then three equilibrium equations were obtained. Physical equations and nonlinear deformation equations of strain at central plane are substituted into superior three equilibrium equations, and then three unsymmetrical nonlinear equations with three deformation displacements were obtained. Solution with expression of Fourier series is substituted into fundamental equations; correspondingly fundamental equations with expression of Fourier series were obtained. The problem was solved by modified iteration method under the boundary conditions of clamped edges. As an example, the problem of circular thin plate with variable thickness subjected to loads with cosin form was studied.Characteristic curves of the load varying with the deflection were plotted. The curves vary with the variation of the parameter of variable thickness. Its solution is accordant with physical conception.

  20. NON-LINEAR DYNAMIC BEHAVIOR OF THERMOELASTIC CIRCULAR PLATE WITH VARYING THICKNESS SUBJECTED TO NON- CONSERVATIVE LOADING

    Institute of Scientific and Technical Information of China (English)

    WANG Zhongmin; GAO Jingbo; LI Huixia; LIU Hongzhao

    2008-01-01

    The non-linear dynamic behaviors of thermoelastic circular plate with varying thickness subjected to radially uniformly distributed follower forces are considered. Two coupled non-linear differential equations of motion for this problem are derived in terms of the transverse deflection and radial displacement component of the mid-plane of the plate. Using the Kantorovich averaging method, the differential equation of mode shape of the plate is derived, and the eigenvalue problem is solved by using shooting method. The eigencurves for frequencies and critical loads of the circular plate with unmovable simply supported edge and clamped edge are obtained. The effects of the variation of thickness and temperature on the frequencies and critical loads of the thermoelastic circular plate subjected to radially uniformly distributed follower forces are then discussed.

  1. The Timoshenko-Reissner generalized model of a plate highly nonuniform in thickness

    Science.gov (United States)

    Morozov, N. F.; Tovstik, P. E.; Tovstik, T. P.

    2016-08-01

    A thin plate fabricated of material that is transversally isotropic and nonuniform in thickness is considered. The model of the monolayer transversally homogeneous isotropic plate, which is approximately equivalent to a thickness-nonuniform plate in the deflection and in the lowest frequencies of free vibrations, is constructed. The range of applicability of the model constructed is very wide. The main result of this study is a formula for calculating the transverse-shear rigidity of an equivalent transversally isotropic plate.

  2. Spatial Evolution of the Thickness Variations over a CFRP Laminated Structure

    Science.gov (United States)

    Davila, Yves; Crouzeix, Laurent; Douchin, Bernard; Collombet, Francis; Grunevald, Yves-Henri

    2017-01-01

    Ply thickness is one of the main drivers of the structural performance of a composite part. For stress analysis calculations (e.g., finite element analysis), composite plies are commonly considered to have a constant thickness compared to the reality (coefficients of variation up to 9% of the mean ply thickness). Unless this variability is taken into account reliable property predictions cannot be made. A modelling approach of such variations is proposed using parameters obtained from a 16-ply quasi-isotropic CFRP plate cured in an autoclave. A discrete Fourier transform algorithm is used to analyse the frequency response of the observed ply and plate thickness profiles. The model inputs, obtained by a mathematical representation of the ply thickness profiles, permit the generation of a representative stratification considering the spatial continuity of the thickness variations that are in good agreement with the real ply profiles spread over the composite part. A residual deformation FE model of the composite plate is used to illustrate the feasibility of the approach.

  3. Effects of Thickness Deviation of Elastic Plates in Multi-Layered Resonance Systems on Frequency Spectra

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui; ZHANG Shu-Yi; FAN Li

    2009-01-01

    A model of high-overtone bulk acoustic resonators is used to study the effects of thickness deviation of elastic plates on resonance frequency spectra in planar multi-layered systems. The resonance frequency shifts induced by the thickness deviations of the elastic plates periodically vary with the resonance order, which depends on the acoustic impedance ratios of the elastic plates to piezoelectric patches. Additionally, the center lines of the frequency shift oscillations Hnearly change with the orders of the resonance modes, and their slopes are sensitive to the thickness deviations of the plates, which can be used to quantitatively evaluate the thickness deviations.

  4. Variational principle and vibration properties of functionally graded circular plate with temperature changes

    Science.gov (United States)

    Fan, Tao; Zou, Guangping

    2012-04-01

    In this paper, the variational principle of functionally graded circular plate is presented by the variational integral method taking temperature change into account. The vibration governing equation is illustrated, which will be benefit for the numerical simulation with finite element method in further investigations. The numerical results show that the natural frequency increases as the graded coefficient increases in the chosen domain. It can be observed that the vibration characteristics are influenced by the temperature changes obviously. Moreover, the natural frequency is larger for thicker FGM circular plates, while it is lower for thinner ones. Furthermore, the first four vibration mode shapes with different thickness of FGM circular plate are illustrated.

  5. 桩帽设计中的厚板分析%THICK PLATE ANALYSIS WITH APPLICATION TO PILE CAP DESIGN

    Institute of Scientific and Technical Information of China (English)

    郑榕明; 张勇慧

    2004-01-01

    The thick plate is commonly used for the pile cap and the transfer plate, and a proper analysis of it can greatly affect the cost of the thick plate. In actual practice, soft support condition is sometimes adopted by engineers for modeling of thick plates. In this paper, the limitations of soft support in the determination of deflection and bending moment with very thick plates are studied. The distribution of superstructure loadings to pile caps and piles is also carefully investigated.

  6. Optimization of Holding Temperature and Holding Thickness for Controlled Rolling on Plate Mill

    Institute of Scientific and Technical Information of China (English)

    HU Xian-lei; ZHAO Zhong; WANG Jun; WANG Zhao-dong; LIU Xiang-hua; WANG Guo-dong

    2006-01-01

    Holding temperature and holding thickness are main parameters for two-phase controlled rolling on plate mill. The optimization of holding temperature and holding thickness for pass schedule calculation of two-phase controlled rolling on plate mill was presented and its feature is as follows: (1) Determination of holding thickness can be automatically obtained based on the influence of mill safety limits, tracking zone length and holding time on holding thickness; (2) Determination of holding temperature can be automatically obtained and the holding time can be reduced as much as possible; (3) Algorithm can modify the holding temperature and thickness depending on slab size and product size.

  7. The sound transmission of finite ribbed plates using a variational

    DEFF Research Database (Denmark)

    Brunskog, Jonas

    2012-01-01

    Many lightweight structures consist of plates being stiffened by ribs. The rib stiffeners can significantly change the vibration field and the radiation behavior of the structure. These type of structures has thus often been studied in the past. However, there is a lack of simplified expressions...... for the sound transmission of these structures. Therefore, simplified expressions for the sound transmission of finite single leaf ribbed plates are derived, using a variational technique based on integral equations of the fluid loaded plate....

  8. Ballistic Behaviour of Thick Steel Armour Plate under Oblique Impact : Experimental Investigation II

    OpenAIRE

    S. N. Dikshit

    1999-01-01

    The ballistic behaviour of thick steel armour plate at different obliquities has been investigated. Ballistic experiments were conducted in the velocity range 300-800 mls at 0°, 15°, 30° and 45° obliquity .A steel, conical projectile or 6.1 mm diameter was impacted on a 10 mm thick steel armour plate. At 30° and 45° obliquity, the plate offers protection up to a striking velocity of 800 mls. At zero obliquity, the plate provides protection below 6~ m/s. The depth of penetration decreases with...

  9. Ballistic Behaviour of Thick Steel Armour Plate under Oblique Impact: Experimental Investigation .

    OpenAIRE

    S. N. Dikshit

    1998-01-01

    The ballistic behaviour of thick steel amlOW- plate has been investigated at different obliquity when impacted by an ogive-shaped steel projectile. The ballistic experiments have been conducted in the velocity range 300-800 m/s. Both the thickness of the target plate and the diameter of the projectile were 20 Inm. At 30 and 45. obliquity 20 mm plate provides full protection at 800 m/s, whereas at 0 and 15. obliquity, the plate provides protection up to 600 m/s. At 15 and 30° obliquity, the pl...

  10. Ballistic Behaviour of Thick Steel Armour Plate under Oblique Impact : Experimental Investigation II

    OpenAIRE

    S. N. Dikshit

    1999-01-01

    The ballistic behaviour of thick steel armour plate at different obliquities has been investigated. Ballistic experiments were conducted in the velocity range 300-800 mls at 0°, 15°, 30° and 45° obliquity .A steel, conical projectile or 6.1 mm diameter was impacted on a 10 mm thick steel armour plate. At 30° and 45° obliquity, the plate offers protection up to a striking velocity of 800 mls. At zero obliquity, the plate provides protection below 6~ m/s. The depth of penetration decreases with...

  11. Ballistic Behaviour of Thick Steel Armour Plate under Oblique Impact: Experimental Investigation .

    OpenAIRE

    S. N. Dikshit

    1998-01-01

    The ballistic behaviour of thick steel amlOW- plate has been investigated at different obliquity when impacted by an ogive-shaped steel projectile. The ballistic experiments have been conducted in the velocity range 300-800 m/s. Both the thickness of the target plate and the diameter of the projectile were 20 Inm. At 30 and 45. obliquity 20 mm plate provides full protection at 800 m/s, whereas at 0 and 15. obliquity, the plate provides protection up to 600 m/s. At 15 and 30° obliquity, the pl...

  12. Double sinusoidal phase modulating laser diode interferometer for thickness measurements of transparent plates

    Institute of Scientific and Technical Information of China (English)

    Dailin Li(李代林); Xiangzhao Wang(王向朝); Yingming Liu(刘英明)

    2004-01-01

    A double sinusoidal phase modulating (SPM) laser diode interferometer for thickness measurements of a transparent plate is presented. A carrier signal is given to the interference signal by using a piezoelectric transducer, and the SPM interferometry is applied to measure the thickness of a transparent plate. By combining the double-modulation technique with the Bessel function ratio method, the measurement error originating from light intensity fluctuations caused by the modulation current can be decreased greatly.The thicknesses of a glass parallel plate and a quartz glass are measured in real time, and the corresponding experimental results are also given.

  13. Numerical and experimental demonstration of shear stress measurement at thick steel plates using acoustoelasticity

    Science.gov (United States)

    Abbasi, Zeynab; Ozevin, Didem

    2015-04-01

    The purpose of this article is to numerically quantify the stress state of complex loaded thick steel plates using the fundamental theory of acoustoelasticity, which is the relationship with stress and ultrasonic velocity in the nonlinear regime. The normal and shear stresses of a thick plate can be measured using a phased array placement of ultrasonic sensors and Rayleigh ultrasonic waves. Three measurement angles (i.e., 0 45 and 90 degrees) are selected since three measurements are needed to solve the stress tensor in an isotropic plate. The ultrasonic data is influenced significantly by the frequency of the Rayleigh waves as well as the thickness of the plate being examined; consequently the overall experimental process is influenced by the measurement parameters. In this study, a numerical demonstration is implemented to extract the nonlinearity coefficients using a 3D structural geometry and Murnaghan material model capable of examining the effects of various plate thicknesses and ultrasonic frequencies on the shear stress measurement. The purpose is that as the thickness becomes smaller, the shear stress becomes negligible at the angled measurement. For thicker cross section, shear stress becomes influential if the depth of penetration of Rayleigh wave is greater than the half of the thickness. The correlation between the depth of penetration and shear stress is then obtained. The numerical results are compared with 1 MHz ultrasonic frequency and a 3/8 inch thick steel plate loaded uniaxially while the measurement direction is angled to have the presence of shear stress in the measurement direction.

  14. Buckling analysis of thick isotropic plates by using exponential shear deformation theory

    Directory of Open Access Journals (Sweden)

    Sayyad A. S.

    2012-12-01

    Full Text Available In this paper, an exponential shear deformation theory is presented for the buckling analysis of thick isotropic plates subjected to uniaxial and biaxial in-plane forces. The theory accounts for a parabolic distribution of the transverse shear strains across the thickness, and satisfies the zero traction boundary conditions on the top and bottom surfaces of the plate without using shear correction factors. Governing equations and associated boundary conditions of the theory are obtained using the principle of virtual work. The simply supported thick isotropic square plates are considered for the detailed numerical studies. A closed form solutions for buckling analysis of square plates are obtained. Comparison studies are performed to verify the validity of the present results. The effects of aspect ratio on the critical buckling load of isotropic plates is investigated and discussed.

  15. Mathematical Modeling of Quasi Static Thermoelastic Transient behavior of thick circular plate with Internal Heat Generation

    Directory of Open Access Journals (Sweden)

    C. M. Bhongade

    2014-09-01

    Full Text Available The present paper deals with the determination of displacement and thermal transient stresses in a thick circular plate with internal heat generation. External arbitrary heat supply is applied at the upper surface of a thick circular plate, whereas the lower surface of a thick circular plate is insulated and heat is dissipated due to convection in surrounding through lateral surface. Here we compute the effects of internal heat generation of a thick circular plate in terms of stresses along radial direction. The governing heat conduction equation has been solved by using integral transform method. The results are obtained in series form in terms of Bessel’s functions and the results for temperature change and stresses have been computed numerically and illustrated graphically.

  16. Effect of mechanical restraint on weldability of reduced activation ferritic/martensitic steel thick plates

    Energy Technology Data Exchange (ETDEWEB)

    Serizawa, Hisashi, E-mail: serizawa@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Nakamura, Shinichiro [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suite, Osaka 565-0871 (Japan); Tanaka, Manabu; Kawahito, Yousuke [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Tanigawa, Hiroyasu [Fusion Research and Development Directorate, Japan Atomic Energy Agency, 2-4 Shirakita, Shirane, Naka, Ibaraki 319-1195 (Japan); Katayama, Seiji [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2011-10-01

    As one of the reduced activation ferritic/martensitic steels, the weldability of thick F82H plate was experimentally examined using new heat sources in order to minimize the total heat input energy in comparison with TIG welding. A full penetration of 32 mm thick plate could be produced as a combination of a 12 mm deep first layer generated by a 10 kW fiber laser beam and upper layers deposited by a plasma MIG hybrid welding with Ar + 2%O shielding gas. Also, the effect of mechanical restraint on the weldability under EB welding of thick F82H plate was studied by using FEM to select an appropriate specimen size for the basic test. The appropriate and minimum size for the basic test of weldability under EB welding of 90 mm thick plate might be 200 mm in length and 400 mm in width where the welding length should be about 180 mm.

  17. Theory for laminated plates with a through-the-thickeness crack

    Energy Technology Data Exchange (ETDEWEB)

    Chen, E. P.

    1980-01-01

    The flexural response of a laminated plate with a through-the-thickness crack was considered in this investigation. A laminated plate theory of the Reissner type has been developed to treat this problem. For demonstration purposes, the theory was applied to a balanced symmetric laminate which contains a through-the-thickness central crack. The stress intensity factor for the crack was determined and the influences of the various material and geremetric parameters on the stress intensity factor were discussed.

  18. Oscillating layer thickness and vortices generated in oscillation of finite plate

    Science.gov (United States)

    Sin, V. K.; Wong, I. K.

    2016-06-01

    Moving mesh strategy is used in the model of flow induced by oscillating finite plate through software - COMSOL Multiphysics. Flow is assumed to be laminar and arbitrary Lagrangian-Eulerian method is used for moving mesh in the simulation. Oscillating layer thickness is found which is different from the analytical solution by 2 to 3 times depends on the oscillating frequency. Vortices are also observed near the oscillating finite plate because of the edge effect of the finite plate.

  19. XRD and TEM study of bainitic ferrite plate thickness in nanostructured, carbide free bainitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Yoozbashi, M.N., E-mail: n_yoozbashi@sut.ac.ir [University of Applied Science and Technology, Tabriz (Iran, Islamic Republic of); Yazdani, S., E-mail: yazdani@sut.ac.ir [Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of)

    2015-06-15

    It is well documented that much of the strength and hardness of nanostructured, carbide free bainitic steels come from the very small thickness of bainitic ferrite plates. In the current work, the Williamson–Hall method has been used to determine the bainitic ferrite plate thickness. The fitting of X-ray peaks to various functions showed good coefficient of determination values for Gaussian function compared to the Cauchy and Pseudo-Voigt functions. The thickness of bainitic ferrite plates was measured by distinguishing the contribution of very small plates on peak broadening from the lattice microstrain and instrumental effects. The results showed that by decreasing the transformation temperature the bainitic ferrite plate thickness decreases. The determined thicknesses were compared with that of measured from transmission electron microscope micrographs. There is a good qualitative and quantitative agreement between the thicknesses measured using both methods. - Highlights: • A Williamson–Hall technique is proposed for bainitic ferrite thickness measurement. • The technique relies on full width at half maximum of XRD peaks. • The measured sizes were compared with that of determined from TEM micrographs. • There is a good qualitative and quantitative agreement between both methods. • Austenite strength and nucleation driving force lead to microstructural refinement.

  20. Microchannel plate modal gain variations with temperature

    Science.gov (United States)

    Slater, David C.; Timothy, J. G.

    1993-01-01

    Measurements of the modal gain of two high-gain curved-channel microchannel plates (MCPs) at various operating temperatures are presented. Both MCPs were fabricated from the Long Life glass with 12-micron diam channels on 15-micron centers. The modal gain was found to decrease with increasing temperature at a rate of -0.1 percent C. This reduction of gain with temperature is attributed primarily to an axial temperature gradient along each MCP channel creating a nonuniform electric field within the channel that lowers the effective output gain. A lowering of the secondary electron yield resulting from increased phonon scattering of secondary electrons released within the walls of the MCP channels was assessed, but was found to have a negligible contribution to the drop in gain with temperature.

  1. A Comparative Study of Solutions Concerning Thick Elastic Plates on Bi-modulus Foundation

    Directory of Open Access Journals (Sweden)

    Ioana Vlad

    2004-01-01

    Full Text Available The classical bending theory of elastic plates is based upon the assumption that the internal moments are proportional to the curvatures of the median deformed surface. This theory does not include the effects of shear and normal pressure in the plate. The model of a bi-modulus foundation is a realistic generalization of the Winkler’s classical one and is widely used to represent the subgrade of railroad systems, airport lanes [1], [2]. The derived equation of elastic thick plates on bi-modulus foundation considers shear and normal stress as linear variable across the plate thickness. This paper presents numerical solutions for thick plate resting on bi-modulus subgrade. These solutions take into account the shear distortion, and they are compared to the solution obtained by Finite Element Analysis and with the Winkler’s model. Particular solutions for the rectangular plate of clamped boundary, for the hinged rectangular plate and for a semi-elliptical plate, are discussed. The numerical solutions consist of double power series and they were obtained based on the minimum of the total strain energy [1]. Parametric studies have been performed in order to emphasize the effects of the chosen foundation and that of the geometry.

  2. Understanding the antimicrobial activity behind thin- and thick-rolled copper plates.

    Science.gov (United States)

    Yousuf, Basit; Ahire, Jayesh J; Dicks, Leon M T

    2016-06-01

    The aim of this study was to compare the antibacterial properties of the surfaces of copper plates that were rolled to a thickness of 25 and 100 μm. Differences in topology of 25- and 100-μm-thick copper plates were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). Antibacterial activity of the copper surfaces was tested against strains of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Listeria monocytogenes, Salmonella typhimurium, Streptococcus sp. BY1, Enterococcus sp. BY2, and Bacillus cereus BY3. Changes in viable cell numbers were determined by plating onto optimal growth media and staining with LIVE/DEAD BacLight™. Changes in metabolic activity were recorded by expression of the luciferase (lux) gene. Cell morphology was studied using SEM. Accumulation and diffusion of copper from cells were recorded using inductively coupled plasma mass spectroscopy (ICP-MS). Lipid and protein oxidation were recorded spectrophotometrically. Surfaces of 25-μm-thick copper plates were rough compared to that of 100-μm-thick copper plates. For most species, a five-log reduction in cell numbers, cell membrane instability, and a decline in metabolic activity were recorded after 15 min of exposure to 25-μm-thick copper plates. Copper accumulated in the cells, and lipids and proteins were oxidized. The rough surface of thinner copper plates (25 μm thick) released more copper and was more antimicrobial compared to thicker (100 μm) copper plates. Cell death was attributed to destabilization of the cell membrane, lipid peroxidation, and protein oxidation.

  3. Application of the HHT Method to the Non-contact Thickness Measurement of an Axially Moving Thin Plate

    Science.gov (United States)

    Wu, Yangfang; Lu, Qianqian; Xia, Chunlin; Ding, Fan

    2016-06-01

    Non-contact thickness measuring systems can be found in a wide spectrum of technologies. In this paper, Hilbert-Huang transform method is used to analyze the real time signals of a measuring system which includes two round conveyor strings carrying a thin plate, a solar wafer as a sample under test. The vibrations of moving strings and the plate, which are sensitive to moving speed and initial tension in the string, are introduced briefly; the relevant analyses should be helpful for the system design. Using EMD-based time-domain filtering and complementary method, thickness variations and error bands are estimated for different cases. The results show that HHT method as an adaptive time-frequency method, should be potential in measurement engineering applications.

  4. Modelling and analysis of fringing and metal thickness effects in MEMS parallel plate capacitors

    Science.gov (United States)

    Shah, Kriyang; Singh, Jugdutt; Zayegh, Aladin

    2005-12-01

    This paper presents a detailed design and analysis of fringing and metal thickness effects in a Micro Electro Mechanical System (MEMS) parallel plate capacitor. MEMS capacitor is one of the widely deployed components into various applications such are pressure sensor, accelerometers, Voltage Controlled Oscillator's (VCO's) and other tuning circuits. The advantages of MEMS capacitor are miniaturisation, integration with optics, low power consumption and high quality factor for RF circuits. Parallel plate capacitor models found in literature are discussed and the best suitable model for MEMS capacitors is presented. From the equations presented it is found that fringing filed and metal thickness have logarithmic effects on capacitance and depend on width of parallel plates, distance between them and thickness of metal plates. From this analysis a precise model of a MEMS parallel plate capacitor is developed which incorporates the effects of fringing fields and metal thickness. A parallel plate MEMS capacitor has been implemented using Coventor design suite. Finite Element Method (FEM) analysis in Coventorware design suite has been performed to verify the accuracy of the proposed model for suitable range of dimensions for MEMS capacitor Simulations and analysis show that the error between the designed and the simulated values of MEMS capacitor is significantly reduced. Application of the modified model for computing capacitance of a combed device shows that the designed values greatly differ from simulated results noticeably from 1.0339pF to 1.3171pF in case of fringed devices.

  5. Hadron energy resolution as a function of iron plate thickness at ICAL

    CERN Document Server

    Mohan, Lakshmi S; Devi, Moon Moon; Kaur, Daljeet; Choubey, Sandhya; Dighe, Amol; Indumathi, D; Murthy, M V N; Naimuddin, Md

    2014-01-01

    We report on a detailed study of the hadron energy resolution as a function of the thickness of the absorber plates for the proposed Iron Calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO). We compare the hadron resolutions obtained with absorber thicknesses in the range 1.5 -- 8 cm for neutrino interactions in the energy range 2 -- 15 GeV, which is relevant to hadron production in atmospheric neutrino interactions. We find that at lower energies, the thickness dependence of energy resolution is steeper than at higher energies, however there is a constant contribution that dominates at the lower thicknesses discussed in this paper. As a result, the gain in hadron energy resolution with decreasing plate thickness is marginal. We present the results in the form of fits to a function with energy-dependent exponent.

  6. Study of Hypervelocity Projectile Impact on Thick Metal Plates

    Directory of Open Access Journals (Sweden)

    Shawoon K. Roy

    2016-01-01

    Full Text Available Hypervelocity impacts generate extreme pressure and shock waves in impacted targets that undergo severe localized deformation within a few microseconds. These impact experiments pose unique challenges in terms of obtaining accurate measurements. Similarly, simulating these experiments is not straightforward. This study proposed an approach to experimentally measure the velocity of the back surface of an A36 steel plate impacted by a projectile. All experiments used a combination of a two-stage light-gas gun and the photonic Doppler velocimetry (PDV technique. The experimental data were used to benchmark and verify computational studies. Two different finite-element methods were used to simulate the experiments: Lagrangian-based smooth particle hydrodynamics (SPH and Eulerian-based hydrocode. Both codes used the Johnson-Cook material model and the Mie-Grüneisen equation of state. Experiments and simulations were compared based on the physical damage area and the back surface velocity. The results of this study showed that the proposed simulation approaches could be used to reduce the need for expensive experiments.

  7. Study of Pixel Area Variations in Fully Depleted Thick CCD

    Energy Technology Data Exchange (ETDEWEB)

    Kotov, I.V.; O' Connor, P.; Kotov, A.I.; Frank, J.; Kubanek, P.; Prouza, M.; Radeka, V.; Takacs, P.

    2010-06-30

    Future wide field astronomical surveys, like Large Synoptic Survey Telescope (LSST), require photometric precision on the percent level. The accuracy of sensor calibration procedures should match these requirements. Pixel size variations found in CCDs from different manufacturers are the source of systematic errors in the flat field calibration procedure. To achieve the calibration accuracy required to meet the most demanding science goals this effect should be taken into account. The study of pixel area variations was performed for fully depleted, thick CCDs produced in a technology study for LSST. These are n-channel, 100 {micro}m thick devices. We find pixel size variations in both row and column directions. The size variation magnitude is smaller in the row direction. In addition, diffusion is found to smooth out electron density variations. It is shown that the characteristic diffusion width can be extracted from the flat field data. Results on pixel area variations and diffusion, data features, analysis technique and modeling technique are presented and discussed.

  8. Control of Rayleigh-like waves in thick plate Willis metamaterials

    CERN Document Server

    Diatta, Andre; Brûlé, Stéphane; Enoch, Stefan; Guenneau, Sébastien

    2016-01-01

    Recent advances in control of anthropic seismic sources in structured soil led us to explore interactions of elastic waves propagating in plates (with soil parameters) structured with concrete pillars buried in the soil. Pillars are $40$ m in depth and the plate is $100$ m in thickness, so that typical frequencies under study are in the frequency range 4 to 8 Hz, which is compatible with frequency ranges of particular interest in earthquake engineering. It is demonstrated in this paper that two seismic cloaks' configurations allow for an unprecedented flow of elastodynamic energy associated with Rayleigh surface waves. These designs are inspired by some ideal cloaks' parameters deduced from a geometric transform in the Navier equations that preserves the symmetry of the elasticity tensor but leads to Willis' equations as corroborated by numerical simulations. Importantly, we focus our attention on geometric transforms applied to thick plates, which is an intermediate case between thin plates and semi-infinite...

  9. Conformity Check of Thickness to the Crystal Plate λ/4(λ/2

    Directory of Open Access Journals (Sweden)

    Alexander Syuy

    2013-01-01

    Full Text Available This work demonstrates that if crystal plates are identical in thickness in the direction of radiation, the intensity at the output of the polarizer-crystal-crystal-analyzer system equals zero. This means that it is possible to control the difference in thickness between the reference crystal plate (e.g., plates of λ/4 or λ/2 and the examined plate by the intensity of the transmitted radiation. Further, it shows that if nonmonochromatic radiation is used, then the spectrum of radiation at the output is determined by the relative orientation of the optical elements and their sizes. The paper gives the theoretical model for calculations of profile of spectra for the number of important cases of orientation of elements.

  10. A Study on Friction Stir Welding of 12mm Thick Aluminum Alloy Plates

    Institute of Scientific and Technical Information of China (English)

    Deepati Anil Kumar; Pankaj Biswas; Sujoy Tikader; M. M. Mahapatra; N. R. Mandal

    2013-01-01

    Most of the investigations regarding friction stir welding (FSW) of aluminum alloy plates have been limited to about 5 to 6 mm thick plates. In prior work conducted the various aspects concerning the process parameters and the FSW tool geometry were studied utilizing friction stir welding of 12 mm thick commercial grade aluminum alloy. Two different simple-to-manufacture tool geometries were used. The effect of varying welding parameters and dwell time of FSW tool on mechanical properties and weld quality was examined. It was observed that in order to achieve a defect free welding on such thick aluminum alloy plates, tool having trapezoidal pin geometry was suitable. Adequate tensile strength and ductility can be achieved utilizing a combination of high tool rotational speed of about 2000 r/min and low speed of welding around 28 mm/min. At very low and high dwell time the ductility of welded joints are reduced significantly.

  11. Cubic Spline Solutions of Nonlinear Bending and Buckling of Circular Plates with Arbitrarily Variable Thickness

    Institute of Scientific and Technical Information of China (English)

    侯朝胜; 李婧; 龙泉

    2003-01-01

    The cubic B-splines taken as trial function, the large deflection of a circular plate with arbitrarily variable thickness,as well as the buckling load, have been calculated by the method of point collocation. The support can be elastic. Loads imposed can be polynomial distributed loads, uniformly distributed radial forces or moments along the edge respectively or their combinations. Convergent solutions can still be obtained by this method under the load whose value is in great excess of normal one. Under the action of the uniformly distributed loads, linear solutions of circular plates with linearly or quadratically variable thickness are compared with those obtained by the parameter method. Buckling of a circular plate with identical thickness beyond critical thrust is compared with those obtained by the power series method.

  12. Vibration and Buckling Analysis of Moderately Thick Plates using Natural Element Method

    Directory of Open Access Journals (Sweden)

    Mohammad Etemadi

    2015-07-01

    Full Text Available Using natural element method (NEM, the buckling and the free vibration behaviors of moderate thick plates is studied here. The basis of NEM is natural neighbors and Voronoi cells concepts. The shape functions of nodes located in the domain is equal to the proportion of common natural neighbors area divided by area that related by each Voronoi cells. First step in analyzing the moderate thick plates is identification boundaries. This is done by nodes scattering on problem domain. Mindlin/Reissner theory is used to express the equations of moderate thick plate. First and second order shape functions obtained from natural element method are used to discretize differential equations. Using numerical integration on whole discrete equations of domain, stiffness, geometry and mass matrices of plate are obtained. Buckling loads and vibration modes are expressed by substituting these matrices in plate equations of motions. Arbitrary shapes of plate are selected for solution. Comparing the results of the current approach with those obtained by other numerical analytical methods, it is shown that natural element method can solve problems with complex areas accurately.

  13. Crack-growth behavior in thick welded plates of Inconel 718 at room and cryogenic temperatures

    Science.gov (United States)

    Forman, R. G.

    1974-01-01

    Results of mechanical-properties and axial-load fatigue and fracture tests performed on thick welded plates of Inconel 718 superalloy are presented. The test objectives were to determine the tensile strength properties and the crack-growth behavior in electron-beam, plasma-arc, and gas tungsten are welds for plates 1.90 cm (0.75 in) thick. Base-metal specimens were also tested to determine the flaw-growth behavior. The tests were performed in room-temperature-air and liquid nitrogen environments. The experimental crack-growth-rate data are correlated with theoretical crack-growth-rate predictions for semielliptical surface flaws.

  14. Three-dimensional analysis of a thick FGM rectangular plate in thermal environment

    Institute of Scientific and Technical Information of China (English)

    陈伟球; 边祖光; 丁皓江

    2003-01-01

    The thermal behavior of a thick transversely isotropic FGM rectangular plate was investigated within the scope of three-dimensional elasticity. Noticing many FGMs may have temperature-dependent properties, the material constants were further considered as functions of temperature. A solution method based on state-space formulations with a laminate approximate model was proposed. For a thin plate, the method was clarified by comparison with the thin plate theory. The influences of material inhomogeneity and temperature-dependent characteristics were finally discussed through numerical examples.

  15. Effect of Cadmium Plating Thickness on the Charpy Impact Energy of Hydrogen-Charged 4340 Steel

    Science.gov (United States)

    Es-Said, O. S.; Alcisto, J.; Guerra, J.; Jones, E.; Dominguez, A.; Hahn, M.; Ula, N.; Zeng, L.; Ramsey, B.; Mulazimoglu, H.; Li, Yong-Jun; Miller, M.; Alrashid, J.; Papakyriakou, M.; Kalnaus, S.; Lee, E. W.; Frazier, W. E.

    2016-09-01

    Hydrogen was intentionally introduced into ultra-high strength steel by cadmium plating. The purpose was to examine the effect of cadmium plate thickness and hence hydrogen on the impact energy of the steel. The AISI 4340 steel was austenitized at 1000 °C for 1 h, water quenched, and tempered at temperatures between 257 and 593 °C in order to achieve a range of targeted strength levels. The specimens were cadmium plated with 0.00508 mm (0.2 mils), 0.00762 mm (0.3 mils), and 0.0127 mm (0.5 mils). Results demonstrated that the uncharged specimens exhibited higher impact energy values when compared to the plated specimens at all tempering temperatures. The cadmium-plated specimens had very low Charpy impact values irrespective of their ultimate tensile strength values. The model of hydrogen transport by mobile dislocations to the fracture site appears to provide the most suitable explanation of the results.

  16. Distribution of Inherent Strains and Residual Stresses in Medium Thickness Plate Weldment

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A fundamental theory for the analysis of residual weldingstresses and deformation based on the inherent strain distribution along the welded joint is introduced. Distribution of inherent strains and longitudinal residual stresses in medium thickness plate weldment is calculated and analyzed.A new method of calculating inherent strains and longitudinal residual stresses is proposed.

  17. Exact thickness-shear resonance frequency of electroded piezoelectric crystal plates

    Institute of Scientific and Technical Information of China (English)

    WANG Ji; SHEN Li-jun

    2005-01-01

    The determination of the precise thickness-shear frequency of electroded crystal plates has practical importance in quartz crystal resonator design and fabrication, especially when the high fundamental thickness-shear frequency has reduced the crystal plate thickness to such a degree that proper consideration of the effect of electrodes is very important. The electrodes effect as mass loading in the estimation of the resonance frequency has to be modified to consider the stiffness of electrodes, as the relative strength is increasingly noticeable. By following a known procedure in the determination of the thickness-shear frequency of an infinite AT-cut crystal plate, frequency equations of crystal plate without and with piezoelectric effect are obtained in terms of elastic constants and the electrode material density. After solving these equations for the usual design parameters of crystal resonators, the design process can be optimized to pinpoint the precise configuration to avoid time-consuming trial and reduction steps. Since these equations and solutions are presented for widely used materials and parameters, they can be easily integrated into the existing crystal resonator design and manufacturing processes.

  18. ELECTRICALLY FORCED THICKNESS-SHEAR VIBRATIONS OF QUARTZ PLATE WITH NONLINEAR COUPLING TO EXTENSION

    Institute of Scientific and Technical Information of China (English)

    Rongxing Wu; Jiashi Yang; Jianke Du; Ji Wang

    2008-01-01

    We study electrically forced nonlinear thickness-shear vibrations of a quartz plate resonator with relatively large amplitude. It is shown that thickness-shear is nonlinearly coupled to extension due to the well-known Poynting effect in nonlinear elasticity. This coupling is relatively strong when the resonant frequency of the extensional mode is about twice the resonant frequency of the thickness-shear mode. This happens when the plate length/thickness ratio assumes certain values. With this nonlinear coupling, the thickness-shear motion is no longer sinusoidal. Coupling to extension also affects energy trapping which is related to device mounting. When damping is 0.01, nonlinear coupling causes a frequency shift of the order of 10-e which is not insignificant,and an amplitude change of the order of 10-8. The effects are expected to be stronger under real damping of 10-5 or larger. To avoid nonlinear coupling to extension, certain values of the aspect ratio of the plate should be avoided.

  19. Control of Rayleigh-like waves in thick plate Willis metamaterials

    Science.gov (United States)

    Diatta, André; Achaoui, Younes; Brûlé, Stéphane; Enoch, Stefan; Guenneau, Sébastien

    2016-12-01

    Recent advances in control of anthropic seismic sources in structured soil led us to explore interactions of elastic waves propagating in plates (with soil parameters) structured with concrete pillars buried in the soil. Pillars are 2 m in diameter, 30 m in depth and the plate is 50 m in thickness. We study the frequency range 5 to 10 Hz, for which Rayleigh wave wavelengths are smaller than the plate thickness. This frequency range is compatible with frequency ranges of particular interest in earthquake engineering. It is demonstrated in this paper that two seismic cloaks' configurations allow for an unprecedented flow of elastodynamic energy associated with Rayleigh surface waves. The first cloak design is inspired by some approximation of ideal cloaks' parameters within the framework of thin plate theory. The second, more accomplished but more involved, cloak design is deduced from a geometric transform in the full Navier equations that preserves the symmetry of the elasticity tensor but leads to Willis' equations, well approximated by a homogenization procedure, as corroborated by numerical simulations. The two cloaks's designs are strickingly different, and the superior efficiency of the second type of cloak emphasizes the necessity for rigour in transposition of existing cloaks's designs in thin plates to the geophysics setting. Importantly, we focus our attention on geometric transforms applied to thick plates, which is an intermediate case between thin plates and semi-infinite media, not studied previously. Cloaking efficiency (reduction of the disturbance of the wave wavefront and its amplitude behind an obstacle) and protection (reduction of the wave amplitude within the center of the cloak) are studied for ideal and approximated cloaks' parameters. These results represent a preliminary step towards designs of seismic cloaks for surface Rayleigh waves propagating in sedimentary soils structured with concrete pillars.

  20. Thickness measurement system for transparent plates using dual digital versatile disc (DVD) pickups.

    Science.gov (United States)

    Liu, Chien-Hung; Yeh, Shien-Chang; Huang, Hsueh-Liang

    2010-02-01

    A low-cost high-precision thickness measurement system for transparent plates that uses dual digital versatile disc (DVD) pickups is proposed. The two DVD pickups are used as the transmitter and the receiver in the measurement system, respectively. One of the DVD pickups emits a laser to the other DVD pickup (receiver) and projects on the photodiode integrated circuit of the receiver. The transparent plate is placed in the optical path to change the focused point that will affect the focusing error signal (FES) of the receiver. Using the FES, a mathematical model for thickness measurement based on the geometric optical method is developed. The experimental results show that the accuracy is 1.5 microm, and the uncertainty is estimated to be +/-1.37 microm for the measured thickness of 150 microm.

  1. Dynamic stress concentrations in thick plates with two holes based on refined theory

    Institute of Scientific and Technical Information of China (English)

    周伟平; 胡超; 刘殿魁

    2014-01-01

    Based on complex variables and conformal mapping, the elastic wave scat-tering and dynamic stress concentrations in the plates with two holes are studied by the refined dynamic equation of plate bending. The problem to be solved is changed to a set of infinite algebraic equations by an orthogonal function expansion method. As examples, under free boundary conditions, the numerical results of the dynamic moment concen-tration factors in the plates with two circular holes are computed. The results indicate that the parameters such as the incident wave number, the thickness of plates, and the spacing between holes have great effects on the dynamic stress distributions. The results are accurate because the refined equation is derived without any engineering hypothese.

  2. Optimizing rib width to height and rib spacing to deck plate thickness ratios in orthotropic decks

    Directory of Open Access Journals (Sweden)

    Abdullah Fettahoglu

    2016-12-01

    Full Text Available Orthotropic decks are composed of deck plate, ribs, and cross-beams and are frequently used in industry to span long distances, due to their light structures and load carrying capacities. Trapezoidal ribs are broadly preferred as longitudinal stiffeners in design of orthotropic decks. They supply the required stiffness to the orthotropic deck in traffic direction. Trapezoidal ribs are chosen in industrial applications because of their high torsional and buckling rigidity, less material and welding needs. Rib width, height, spacing, thickness of deck plate are important parameters for designing of orthotropic decks. In the scope of this study, rib width to height and rib spacing to deck plate thickness ratios are assessed by means of the stresses developed under different ratios of these parameters. For this purpose a FE-model of orthotropic bridge is generated, which encompasses the entire bridge geometry and conforms to recommendations given in Eurocode 3 Part 2. Afterwards necessary FE-analyses are performed to reveal the stresses developed under different rib width to height and rib spacing to deck plate thickness ratios. Based on the results obtained in this study, recommendations regarding these ratios are provided for orthotropic steel decks occupying trapezoidal ribs.

  3. The Transition from Thick to Thin Plate Wake Physics: Whither Vortex Shedding?

    Science.gov (United States)

    Rai, Man Mohan

    2016-01-01

    The near and very near wake of a flat plate with a circular trailing edge is investigated with data from direct numerical simulations. Computations were performed for six different combinations of the Reynolds numbers based on plate thickness (D) and boundary layer momentum thickness upstream of the trailing edge (theta). Unlike the case of the cylinder, these Reynolds numbers are independent parameters for the flat plate. The separating boundary layers are turbulent in all the cases investigated. One objective of the study is to understand the changes in the wake vortex shedding process as the plate thickness is reduced (increasing theta/D). The value of D varies by a factor of 16 and that of theta by approximately 5 in the computations. Vortex shedding is vigorous in the low theta/D cases with a substantial decrease in shedding intensity in the large theta/D cases. Other shedding characteristics are also significantly altered with increasing theta/D. A visualization of the shedding process in the different cases is provided and discussed. The basic shedding mechanism is explored in depth. The effect of changing theta/D on the time-averaged, near-wake velocity statistics is also discussed. A functional relationship between the shedding frequency and the Reynolds numbers mentioned above is obtained.

  4. Asymptotics of electroelasticity piezoceramic inhomogeneous plate with a circular hole and the thickness polarization

    Directory of Open Access Journals (Sweden)

    Azatyan G.L.

    2012-06-01

    Full Text Available Asymptotic integration of the equations of three-dimensional problems of the theory electroelasticity derived recurrence formulas for determining the components of the stress tensor, displacement vector and electric potential of the plate of infinite longitudinal size with a circular aperture of inhomogeneous in terms of piezoelectric ceramics. The plate is polarized by thickness. Examined cases in which its front surfaces are given electric potentials together with the terms of the first, second or mixed boundary value problems of elasticity theory.

  5. THICKNESS-SHEAR VIBRATION OF CIRCULAR CRYSTAL PLATE IN CYLINDRICAL SHELL AS PRESSURE SENSOR

    Institute of Scientific and Technical Information of China (English)

    HU Yuan-tai; CUI Zhi-jian; JIANG Shu-nong; YANG Jia-shi

    2006-01-01

    Based on the theory for small fields superposed on relatively larger fields in an electroelastic body, a theoretical analysis is performed on a circular plate thicknessshear crystal resonator sealed in a circular cylindrical shell for pressure measurement.A simple expression is obtained for pressure induced frequency shifts in the resonator,which is examined for design optimization. Numerical results show that the frequency shifts depend linearly on the pressure, and that a pressure sensor with a softer outer shell or a smaller thickness ratio of the crystal plate to the outer shell has higher sensitivity.

  6. Laser-multi-pass-narrow-gap-welding of Hot Crack Sensitive Thick Aluminum Plates

    Science.gov (United States)

    Dittrich, D.; Schedewy, R.; Brenner, B.; Standfuß, J.

    Although the current process limitations for laser beam welding of thick aluminum plates (>10 mm) have been overcome by high brilliant multi-kilowatt laser, there are still difficulties resulting from the material physical properties, e.g. the high heat conductivity, the large heat capacity and the high thermal expansion coefficient of aluminum. Especially for very deep weld seams, insufficient dilution of filler wire material in the root of the weld seam and the danger of hot cracks increases. With a new welding technology, the Laser-Multi-Pass-Narrow-Gap-Welding, a innovative approach has been developed to weld thick aluminum plates with highest beam quality lasers and remarkably reduced laser power.

  7. Quantitative Microstructural Characterization of Thick Aluminum Plates Heavily Deformed Using Equal Channel Angular Extrusion

    DEFF Research Database (Denmark)

    Mishin, Oleg; Segal, V.M.; Ferrasse, S.

    2012-01-01

    deg rotations about the longitudinal axis. Statistically robust data were obtained in this work using gallium enhanced microscopy and EBSD mapping of large sample areas. For the plate processed using route A, the fraction of high-angle boundaries was found to strongly depend on the inspection plane......A detailed quantitative analysis of the microstructure has been performed in three orthogonal planes of 15-mm-thick aluminum plates heavily deformed via two equal channel angular extrusion (ECAE) routes. One route was a conventional route A with no rotation between passes. Another route involved...... sequential 90 deg rotations about the normal direction (ND) between passes. The microstructure in the center of these plates, and especially the extent of microstructural heterogeneity, has been characterized quantitatively and compared with that in bar samples extruded via either route A or route Bc with 90...

  8. The vibration and stability analysis of moderate thick plates by the method of lines

    Science.gov (United States)

    Tang, Shou-Gao; Yuan, Si

    1992-06-01

    The method of lines based on Hu Hai-chang's theory for the vibration and stability of moderate thick plates is developed. The standard nonlinear ordinary differential equation (ODE) system for natural frequencies and critical load is given by use of ODE techniques; any indicated eigenvalue could be obtained directly from ODE solver by employing the so-called initial eigenfunction technique instead of the mode orthogonality condition. Numerical examples show that the present method is very effective and reliable.

  9. AN EXACT ANALYSIS OF FORCED THICKNESS-TWIST VIBRATIONS OF MULTI-LAYERED PIEZOELECTRIC PLATES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper deals with the thickness-twist vibration of a multi-layered rectangular piezoelectric plate of crystals of 6 mm symmetry or polarized ceramics. An exact solution is obtained from the three-dimensional equations of linear piezoelectricity. The solution is useful to the understanding and design of composite piezoelectric devices. A piezoelectric resonator, a piezoelectric transformer, and a piezoelectric generator are analyzed as examples.

  10. Analytical investigation on axisymmetric free vibrations of moderately thick circular functionally graded plate integrated with piezoelectric layers

    Energy Technology Data Exchange (ETDEWEB)

    Rastgoo, A. [University of Tehran, Tehran (Iran, Islamic Republic of); Ebrahimi, F. [lmam Khomeini International University, Qazvin (Iran, Islamic Republic of); Kargarnovin, M. H. [Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2008-06-15

    In this paper, a free vibration analysis of moderately thick circular functionally graded (FG) plate integrated with two thin piezoelectric (PZT4) layers is presented based on Mindlin plate theory. The material properties of the FG core plate are assumed to be graded in the thickness direction, while the distribution of electric potential field along the thickness of piezoelectric layers is simulated by sinusoidal function. The differential equations of motion are solved analytically for two boundary conditions of the plate: clamped edge and simply supported edge. The analytical solution is validated by comparing the obtained resonant frequencies with those of an isotropic host plate. The emphasis is placed on investigating the effect of varying the gradient index of FG plate on the free vibration characteristics of the structure. Good agreement between the results of this paper and those of the finite element analyses validated the presented approach

  11. Propagation of the transverse normal stress in a thick plate due to distributed lateral impulsive loadings

    Science.gov (United States)

    Oline, L. W.

    1972-01-01

    A theoretical study of the elastic stresses produced in an infinite plate when struck by a high-speed object is presented. The solution is obtained by means of linear elasticity. Laplace transformation techniques are employed to solve the axisymmetric problem. The plate is loaded normal to its surface with a uniform load over a circular area. The normal stress at the wave front of the unreflected dilatation wave along the axis and its variation with the radius of loading are determined. Various facets of the problem are discussed.

  12. Velocity Field and Variation of Wall Thickness During Tube Dieless Upsetting

    Institute of Scientific and Technical Information of China (English)

    王忠堂; 栾瑰馥; 张士宏

    2004-01-01

    Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and (√1 + Rs) (Rs is sectional increase ratio of tube), the theoretical calculated results of wall thickness during tube dieless upsetting are very approximate to the experimental one. As the width of deformation field increases, both the variation of wall thickness and the derivative of wall thickness variation to width of deformation field (tf/to) reduce.

  13. Quasi-Rayleigh waves in butt-welded thick steel plate

    Science.gov (United States)

    Kamas, Tuncay; Giurgiutiu, Victor; Lin, Bin

    2015-03-01

    This paper discusses theoretical and experimental analyses of weld guided surface acoustic waves (SAW) through the guided wave propagation (GWP) analyses. The GWP analyses have been carried out by utilizing piezoelectric wafer active sensors (PWAS) for in situ structural inspection of a thick steel plate with butt weld as the weld bead is ground flush. Ultrasonic techniques are commonly used for validation of welded structures in many in-situ monitoring applications, e.g. in off-shore structures, in nuclear and pressure vessel industries and in a range of naval applications. PWAS is recently employed in such ultrasonic applications as a resonator as well as a transducer. Quasi-Rayleigh waves a.k.a. SAW can be generated in relatively thick isotropic elastic plate having the same phase velocity as Rayleigh waves whereas Rayleigh waves are a high frequency approximation of the first symmetric (S0) and anti-symmetric (A0) Lamb wave modes. As the frequency becomes very high the S0 and the A0 wave speeds coalesce, and both have the same value. This value is exactly the Rayleigh wave speed and becomes constant along the frequency i.e. Rayleigh waves are non-dispersive guided surface acoustic waves. The study is followed with weld-GWP tests through the pitch-catch method along the butt weld line. The tuning curves of quasi-Rayleigh wave are determined to show the tuning and trapping effect of the weld bead that has higher thickness than the adjacent plates on producing a dominant quasi-Rayleigh wave mode. The significant usage of the weld tuned and guided quasi-Rayleigh wave mode is essentially discussed for the applications in the in-situ inspection of relatively thick structures with butt weld such as naval offshore structures. The paper ends with summary, conclusions and suggestions for future work.

  14. Quasi-Rayleigh waves in butt-welded thick steel plate

    Energy Technology Data Exchange (ETDEWEB)

    Kamas, Tuncay, E-mail: kamas@email.sc.edu, E-mail: victorg@sc.edu, E-mail: linbin@cec.sc.edu; Giurgiutiu, Victor, E-mail: kamas@email.sc.edu, E-mail: victorg@sc.edu, E-mail: linbin@cec.sc.edu; Lin, Bin, E-mail: kamas@email.sc.edu, E-mail: victorg@sc.edu, E-mail: linbin@cec.sc.edu [Mechanical Engineering University of South Carolina, 300 Main Str., Columbia, SC 29208 (United States)

    2015-03-31

    This paper discusses theoretical and experimental analyses of weld guided surface acoustic waves (SAW) through the guided wave propagation (GWP) analyses. The GWP analyses have been carried out by utilizing piezoelectric wafer active sensors (PWAS) for in situ structural inspection of a thick steel plate with butt weld as the weld bead is ground flush. Ultrasonic techniques are commonly used for validation of welded structures in many in-situ monitoring applications, e.g. in off-shore structures, in nuclear and pressure vessel industries and in a range of naval applications. PWAS is recently employed in such ultrasonic applications as a resonator as well as a transducer. Quasi-Rayleigh waves a.k.a. SAW can be generated in relatively thick isotropic elastic plate having the same phase velocity as Rayleigh waves whereas Rayleigh waves are a high frequency approximation of the first symmetric (S0) and anti-symmetric (A0) Lamb wave modes. As the frequency becomes very high the S0 and the A0 wave speeds coalesce, and both have the same value. This value is exactly the Rayleigh wave speed and becomes constant along the frequency i.e. Rayleigh waves are non-dispersive guided surface acoustic waves. The study is followed with weld-GWP tests through the pitch-catch method along the butt weld line. The tuning curves of quasi-Rayleigh wave are determined to show the tuning and trapping effect of the weld bead that has higher thickness than the adjacent plates on producing a dominant quasi-Rayleigh wave mode. The significant usage of the weld tuned and guided quasi-Rayleigh wave mode is essentially discussed for the applications in the in-situ inspection of relatively thick structures with butt weld such as naval offshore structures. The paper ends with summary, conclusions and suggestions for future work.

  15. EVALUATION OF TERMINAL VERTEBRAL PLATE ON CERVICAL SPINE AT DIFFERENT AGE GROUPS AND ITS CORRELATION WITH INTERVERTEBRAL DISC THICKNESS

    Science.gov (United States)

    Luiz Vieira, Juliano Silveira; da Silva Herrero, Carlos Fernando Pereira; Porto, Maximiliano Aguiar; Nogueira Barbosa, Marcello Henrique; Garcia, Sérgio Britto; Zambelli Ramalho, Leandra Náira; Aparecido Defino, Helton Luiz

    2015-01-01

    To evaluate, by means of histomorphometry, terminal vertebral plate thickness, intervertebral disc thickness and its correlation on different age groups, seeking to identify its correlation. Methods: C4-C5 and C5-C6 cervical segments removed from human cadavers of both genders were assessed and divided into five groups of 10-year age intervals, from 21 years old. TVP and intervertebral disc thickness evaluation was made by means of histomorphometry of histological slides stained with hematoxylin and eosyn. Lower C4 TVP, upper C5 TVP, and upper C6 TVP de were compared between each other and to the interposed intervertebral disc thickness between relevant TVP. Results: The thickness of terminal vertebral plates adjacent to the same ID did not show statistic differences. However, the comparison of upper and lower vertebral plates thickness on the same cervical vertebra (C5), showed statistical difference on all age groups studied. We found a statistical correlation coefficient above 80% between terminal vertebral plate and adjacent intervertebral disc, with a proportional thickness reduction of both structures on the different cervical levels studied, and also on the different age groups assessed. Conclusion: Terminal vertebral plate shows a morphologic correlation with the intervertebral disc next to it, and does not show correlation with the terminal vertebral plate on the same vertebra. PMID:26998448

  16. Effective elastic thickness variations along the Andean margin and their relationship to subduction geometry

    Science.gov (United States)

    PéRez-Gussinyé, M.; Lowry, A. R.; Phipps Morgan, J.; Tassara, A.

    2008-02-01

    We present a new map of the spatial variations in effective elastic thickness, Te, along the Andes estimated using Bouguer coherence. The Te variations reflect interactions between subducting slab and preexisting terrane structure. In the forearc, conductive cooling of the continent by the subducting slab exerts primary control on rigidity, resulting in Te that is highest (˜40 km) where the oceanic lithosphere is oldest and coldest (˜20°S). In the central Andes, Te is relatively low (˜20 km) along the volcanic chain and the Altiplano and Puna plateaus. We interpret this weakening to reflect a high geothermal gradient maintained by advective magmatic processes, a shallow and hot asthenosphere, and a very weak lower crust throughout this region. East of the plateaus, high Te delineates underthrusting of the Brazilian shield. Finally, north and south of the plateaus, flat subduction areas are characterized by high Te, high shear wave velocity, thick thermal lithosphere, and low heat flow, indicating that continental lithosphere there is thicker, colder, and stronger. On the basis of these relationships we suggest that variations in slab dip along the margin relate to variations in structure of the continental lithosphere. In particular, we propose that upper plate structure influences the width and viscosity of the asthenospheric wedge, which control the suction moment responsible for the subduction angle at depths ≥70-100 km. For example, when oceanic lithosphere subducts beneath thin continental lithosphere, the low-viscosity asthenosphere allows the slab to detach from the continent and sink into the mantle at normal angles. However, when oceanic lithosphere subducts close or beneath thick and strong continental lithosphere, the asthenospheric wedge narrows and corner flow drags high-viscosity mantle from the base of the thick (>150 km), cold continent into the wedge. Suction forces increase with both narrowing of the wedge and its increasing viscosity. We

  17. Joint inversion of local, regional and teleseismic data for crustal thickness in the Eurasia-Africa plate boundary region

    Science.gov (United States)

    Marone, Federica; van der Meijde, Mark; van der Lee, Suzan; Giardini, Domenico

    2003-08-01

    A new map for the Moho discontinuity (EAM02) in the Eurasia-Africa plate boundary region is presented. Reliable results have also been obtained for the southern and eastern Mediterranean Basin, the northern African coasts and the eastern Atlantic Ocean, regions only occasionally considered in studies on the Mediterranean region. The Moho topography model is derived from two independent sets of constraints. Information contained in the fundamental and higher-mode Rayleigh waves obtained from waveform modelling is used to constrain the Moho depth between estimates of crustal thickness taken from published reflection and refraction surveys, gravity studies and receiver function analysis. Strong lateral variations in the Moho topography have been observed in the Mediterranean Sea, confirming the complex evolution of this plate boundary region. In the west, the Moho discontinuity has been found at 15-20 km depth, suggesting extended and, at least in some locations, oceanic crust, while in the east the crust is on average 25-30 km thick. There it is interpreted either as Mesozoic oceanic or thinned Precambrian continental crust covered by thick sedimentary deposits. Standard continental crust (30-35 km) is observed along the eastern part of the northern African coast, while to the west a rapid change from a relatively deep Moho (down to 42 km) below the Atlas Mountain Range to the thin crust of the southwestern Mediterranean Sea has been found. The crust beneath the eastern North Atlantic Ocean can be up to 5 km thicker compared with standard oceanic crust (6 km). The crust has been interpreted to be heterogeneous as a consequence of irregular magma supply at the Mid-Atlantic ridge. In addition, serpentinization of the sub-Moho mantle could contribute to the imaging of apparently anomalous thick oceanic crust. In Europe, the presence of crustal roots (>45 km) beneath the major mountain belts has been confirmed, while thin crust (isostatic compensation at 60 km depth

  18. Thermoelastic Thick Plate under Illumination of a Uniform Laser Beam with one Relaxation time

    Directory of Open Access Journals (Sweden)

    Ezzat. F. Henain

    2013-05-01

    Full Text Available The problem of thermoelasticity, based on the theory of Lord and Shulman (L-S with one relaxation time, is used to solve a one dimensional boundary value problem of a thick plate. The upper surface of the medium is taken as traction free and heated by a pulsed laser beam. The lower surface of the medium rests on a rigid and thermally isolated. The general solution is obtained in the Laplace transform domain. Approximate small time analytical solutions to temperature, stress and displacement are obtained. Results of this problem are presented graphically.

  19. Measuring the Average Thickness of a Plate Using a Bayesian Method and Free Vibration Data

    Science.gov (United States)

    2011-09-01

    form, the model is constructed with the implicit assumption that the corrosion is uniform. A more detailed model that included details of the pitting ...PROCEDURE The test specimen was a 0.76m by 0.60m (30” by 24”, 5:4 aspect ratio), 1.55mm (1/16”) thick 6061 -T6 aluminum plate. The density was...considering corrosion effect.” Marine Struc- tures, 21(4):402 – 419. [3] T. Nakai, H. Matsushita, N. Yamamoto, and H. Arai, 2004. “Effect of pitting

  20. Investigation of reactivity variations of the Isfahan MNSR reactor due to variations in the thickness of the core top beryllium layer using WIMSD and MCNP codes

    Directory of Open Access Journals (Sweden)

    A Shirani

    2010-12-01

    Full Text Available In this work, the Isfahan Miniature Neutron Source Reactor (MNSR is first simulated using the WIMSD code, and its fuel burn-up after 7 years of operation ( when the reactor was revived by adding a 1.5 mm thick beryllium shim plate to the top of its core and also after 14 years of operation (total operation time of the reactor is calculated. The reactor is then simulated using the MCNP code, and its reactivity variation due to adding a 1.5 mm thick beryllium shim plate to the top of the reactor core, after 7 years of operation, is calculated. The results show good agreement with the available data collected at the revival time. Exess reactivity of the reactor at present time (after 14 years of operation and after 7 years of the the reactor revival time is also determined both experimentally and by calculation, which show good agreement, and indicate that at the present time there is no need to add any further beryllium shim plate to the top of the reactor core. Furthermore, by adding more beryllium layers with various thicknesses to the top of the reactor core, in the input program of the MCNP program, reactivity value of these layers is calculated. From these results, one can predict the necessary beryllium thickness needed to reach a desired reactivity in the MNSR reactor.

  1. Along-strike variation in subducting plate velocity induced by along-strike variation in overriding plate structure: Insights from 3D numerical models

    Science.gov (United States)

    Rodríguez-González, Juan; Billen, Magali I.; Negredo, Ana M.; Montesi, Laurent G. J.

    2016-10-01

    Subduction dynamics can be understood as the result of the balance between driving and resisting forces. Previous work has traditionally regarded gravitational slab pull and viscous mantle drag as the main driving and resistive forces for plate motion respectively. However, this paradigm fails to explain many of the observations in subduction zones. For example, subducting plate velocity varies significantly along-strike in many subduction zones and this variation is not correlated to the age of subducting lithosphere. Here we present three-dimensional and time-dependent numerical models of subduction. We show that along-strike variations of the overriding plate thermal structure can lead to along-strike variations in subducting plate velocity. In turn, velocity variations lead to significant migration of the Euler pole over time. Our results show that the subducting plate is slower beneath the colder portion of the overriding plate due to two related mechanisms. First, the mantle wedge beneath the colder portion of the overriding plate is more viscous, which increases mantle drag. Second, where the mantle wedge is more viscous, hydrodynamic suction increases, leading to a lower slab dip. Both factors contribute to decreasing subducting plate velocity in the region; therefore, if the overriding plate is not uniform, the resulting velocity varies significantly along-strike, which causes the Euler pole to migrate closer to the subducting plate. We present a new mechanism to explain observations of subducting plate velocity in the Cocos and Nazca plates. These results shed new light on the balance of forces that control subduction dynamics and prove that future studies should take into consideration the three-dimensional structure of the overriding plate.

  2. The Crustal Thickness of the Philippine Sea Plate Derived from Gravity Data

    Directory of Open Access Journals (Sweden)

    Horng-Yuan Yen

    2015-01-01

    Full Text Available We constructed a new free-air gravity anomaly map of the Philippine Sea Plate (PSP using ship-tracked gravity data from the National Geophysical Data Center (NGDC. Our results show that the isogals trend correlates well with the tectonic structures in the PSP. After removing the gravity induced by sea water from the free-air gravity data, we obtained the regional Bouguer gravity anomaly, which is later used to compute the Moho geometry in the PSP by applying the Parker-Oldenburg iterative method. Our results indicate that in the southern part of the West Philippine Basin (WPB the crustal thickness is nearly homogeneous with a value of about 5 km, which implies that the WPB is quite stable. The low-amplitude and near-zero free-air gravity anomalies clearly indicate that the whole WPB, except at trenches and island arcs, is nearly in a state of isostatic equilibrium. The average crustal thickness of the Palau Kyushu Ridge (PKR is more than 10 km. In the eastern PSP the crustal thickness gradually increases eastward. Our results also imply that a relatively thin and low density mantle exists beneath the Parece Vela Basin (PVB as a consequence of back-arc spreading and serpentinized upwells of the thin crustal thickness.

  3. Ageing behavior of an Al-Zn-Mg-Cu alloy pre-stretched thick plate

    Institute of Scientific and Technical Information of China (English)

    Zhihui Li; Baiqing Xiong; Yongan Zhang; Baohong Zhu; Feng Wang; Hongwei Liu

    2007-01-01

    The ageing behavior of a pre-stretched thick plate of Al-Zn-Mg-Cu alloy was systemically studied including one-step ageing,two-step ageing, and retrogression and reageing treatment (RRA). One-step ageing of the alloy resulted in peak ultimate tensile strengths of 595 and 575 MPa after 22 and 6 h at 120 and 135℃, respectively. The strengthening phase in peak aged (T6 temper) alloy contained GP zones and the η' phase predominantly. After two-step ageing, the electrical conductivity was increased markedly, but the pre-stretched thick plate sacrificed a great loss of strength. RRA treatment provided a method for maintaining the strength close to that obtained by T6 temper and for obtaining the high electrical conductivity close to that obtained by T7 temper; the ultimate tensile strength and electrical conductivity were 583 MPa and 21.0 MS/m, respectively. TEM analysis of T7 and RRA specimens revealed two types of precipitates that contributed to age strengthening i.e. the η' and η phases.

  4. Azimuthal seismic anisotropy in the Earth's upper mantle and the thickness of tectonic plates

    Science.gov (United States)

    Schaeffer, A. J.; Lebedev, S.; Becker, T. W.

    2016-11-01

    Azimuthal seismic anisotropy, the dependence of seismic wave speeds on propagation azimuth, is largely due to fabrics within the Earth's crust and mantle, produced by deformation. It thus provides constraints on the distribution and evolution of deformation within the upper mantle. Here, we present a new global, azimuthally anisotropic model of the crust, upper mantle and transition zone. Two versions of this new model are computed: the rough SL2016svAr and the smooth SL2016svA. Both are constrained by a very large data set of waveform fits (˜750 000 vertical component seismogram fits). Automated, multimode waveform inversion was used to extract structural information from surface and S wave forms in broad period ranges (dominantly from 11 to 450 s, with the best global sampling in the 20-350 s range), yielding resolving power from the crust down to the transition zone. In our global tomographic inversion, regularization of anisotropy is implemented to more uniformly recover the amplitude and orientation of anisotropy, including near the poles. Our massive waveform data set, with complementary large global networks and high-density regional array data, produces improved resolution of global azimuthal anisotropy patterns. We show that regional scale variations, related to regional lithospheric deformation and mantle flow, can now be resolved by the global models, in particular in densely sampled regions. For oceanic regions, we compare quantitatively the directions of past and present plate motions and the fast-propagation orientations of anisotropy. By doing so, we infer the depth of the boundary between the rigid, high-viscosity lithosphere (preserving ancient, frozen fabric) and the rheologically weak asthenosphere (characterized by fabric developed recently). The average depth of thus inferred rheological lithosphere-asthenosphere boundary (LAB) beneath the world's oceans is ˜115 km. The LAB depth displays a clear dependence on the age of the oceanic

  5. Simulation studies of hadron energy resolution as a function of iron plate thickness at INO-ICAL

    Science.gov (United States)

    Lakshmi, S. M.; Ghosh, A.; Devi, M. M.; Kaur, D.; Choubey, S.; Dighe, A.; Indumathi, D.; Murthy, M. V. N.; Naimuddin, Md

    2014-09-01

    We report on a detailed simulation study of the hadron energy resolution as a function of the thickness of the absorber plates for the proposed Iron Calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO). We compare the hadron resolutions obtained with absorber thicknesses in the range 1.5-8 cm for neutrino interactions in the energy range 2-15 GeV, which is relevant to hadron production in atmospheric neutrino interactions. We find that at lower energies, the thickness dependence of energy resolution is steeper than at higher energies, however there is a thickness-independent contribution that dominates at the lower thicknesses discussed in this work. As a result, the gain in hadron energy resolution with decreasing plate thickness is marginal. We present the results in the form of fits to a function with energy-dependent exponent.

  6. Thermal buckling analysis of annular FGM plate having variable thickness under thermal load of arbitrary distribution by finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Ghomshei, Mansour Mohieddin; Abbasi, Vahid [Islamic Azad University, Alborz (Iran, Islamic Republic of)

    2013-04-15

    In this paper, a finite element formulation is developed for analyzing the axisymmetric thermal buckling of FGM annular plates of variable thickness subjected to thermal loads generally distributed nonuniformly along the plate radial coordinate. The FGM assumed to be isotropic with material properties graded in the thickness direction according to a simple power-law in terms of the plate thickness coordinate, and has symmetry with respect to the plate midplane. At first, the pre-buckling plane elasticity problem is developed and solved using the finite element method, to determine the distribution of the pre-buckling in-plane forces in terms of the temperature rise distribution. Subsequently, based on Kierchhoff plate theory and using the principle of minimum total potential energy, the weak form of the differential equation governing the plate thermal stability is derived, then by employing the finite element method, the stability equations are solved numerically to evaluate the thermal buckling load factor. Convergence and validation of the presented finite element model are investigated by comparing the numerical results with those available in the literature. Parametric studies are carried out to cover the effects of parameters including thickness-to-radius ratio, taper parameter and boundary conditions on the thermal buckling load factor of the plates.

  7. Effect of stiffness and thickness ratio of host plate and piezoelectric patches on reduction of the stress concentration factor

    Science.gov (United States)

    Fesharaki, Javad Jafari; Madani, Seyed Ghasem; Golabi, Sa'id

    2016-09-01

    This paper focuses on the effects of stiffness ratio and thickness ratio on reducing stress concentration factor using piezoelectric patches in a rectangular plate with a hole, as a classical shape. Various locations of actuators and induction of positive/negative strains into the host plate are investigated and the best location of patches is presented. The study investigated the ratio effects and piezoelectric patches bounded on a rectangular host plate having various thicknesses and materials. Results show that the best position of actuators varies based on values of thickness and stiffness ratios of the host plate and piezoelectric patches. Also, the location of maximum stress concentration is transmitted from top and bottom of the hole to another point around the edge by changing the location of the piezoelectric actuators. To verify the results, some experimental tests are applied. The results show good agreement between the finite element analysis and experimental tests.

  8. MODIFIED LAYER REMOVAL METHOD FOR MEASUREMENT OF RESIDUAL STRESS DISTRIBUTION IN THICK PRE-STRETCHED ALUMINUM PLATE

    Institute of Scientific and Technical Information of China (English)

    WANGShu-hong; ZUODun-wen; WANGMin; WANGZong-rong

    2004-01-01

    The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predict and control the machining distortion, the residual stress distribution in the thick plate must be measured firstly. The modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. The residual stress distribution in specimen of 7050T7451 plate is measured by using the method, and measurement results are analyzed and compared with data obtained by other methods. The method is effective to measure the residual stress.

  9. Hybrid/Tandem Laser-Arc Welding of Thick Low Carbon Martensitic Stainless Steel Plates =

    Science.gov (United States)

    Mirakhorli, Fatemeh

    High efficiency and long-term life of hydraulic turbines and their assemblies are of utmost importance for the hydropower industry. Usually, hydroelectric turbine components are made of thick-walled low carbon martensitic stainless steels. The assembly of large hydroelectric turbine components has been a great challenge. The use of conventional welding processes involves typical large groove design and multi-pass welding to fill the groove which exposes the weld to a high heat input creating relatively large fusion zone and heat affected zone. The newly-developed hybrid/tandem laser-arc welding technique is believed to offer a highly competitive solution to improve the overall hydro-turbine performance by combining the high energy density and fast welding speed of the laser welding technology with the good gap bridging and feeding ability of the gas metal arc welding process to increase the productivity and reduce the consumable material. The main objective of this research work is to understand different challenges appearing during hybrid laser-arc welding (HLAW) of thick gauge assemblies of low carbon 13%Cr- 4%Ni martensitic stainless steel and find a practical solution by adapting and optimizing this relatively new welding process in order to reduce the number of welding passes necessary to fill the groove gap. The joint integrity was evaluated in terms of microstructure, defects and mechanical properties in both as-welded and post-welded conditions. A special focus was given to the hybrid and tandem laser-arc welding technique for the root pass. Based on the thickness of the low carbon martensitic stainless steel plates, this work is mainly focused on the following two tasks: • Single pass hybrid laser-arc welding of 10-mm thick low carbon martensitic stainless steel. • Multi-pass hybrid/tandem laser-arc welding of 25-mm thick martensitic stainless steel.

  10. Spatial variations of effective elastic thickness of the Lithosphere in the Southeast Asia regions

    Science.gov (United States)

    Shi, Xiaobin; Kirby, Jon; Yu, Chuanhai; Swain, Chris; Zhao, Junfeng

    2016-04-01

    The effective elastic thickness Te corresponds to the thickness of an idealized elastic beam that would bend similarly to the actual lithosphere under the same applied loads, and could provide important insight into rheology and state of stress. Thus, it is helpful to improve our understanding of the relationship between tectonic styles, distribution of earthquakes and lithospheric rheology in various tectonic settings. The Southeast Asia, located in the southeastern part of the Eurasian Plate, comprises a complex collage of continental fragments, volcanic arcs, and suture zones and marginal oceanic basins, and is surrounded by tectonically active margins which exhibit intense seismicity and volcanism. The Cenozoic southeastward extrusion of the rigid Indochina Block due to the Indo-Asian collision resulted in the drastic surface deformation in the western area. Therefore, a high resolution spatial variation map of Te might be a useful tool for the complex Southeast Asia area to examine the relationships between surface deformation, earthquakes, lithospheric structure and mantle dynamics. In this study, we present a high-resolution map of spatial variations of Te in the Southeast Asia area using the wavelet method, which convolves a range of scaled wavelets with the two data sets of Bouguer gravity anomaly and topography. The topography and bathymetry grid data was extracted from the GEBCO_08 Grid of GEBCO digital atlas. The pattern of Te variations agrees well with the tectonic provinces in the study area. On the whole, low lithosphere strength characterizes the oceanic basins, such as the South China Sea, the Banda sea area, the Celebes Sea, the Sulu Sea and the Andaman Sea. Unlike the oceanic basins, the continental fragments show a complex pattern of Te variations. The Khorat plateau and its adjacent area show strong lithosphere characteristics with a Te range of 20-50 km, suggesting that the Khorat plateau is the strong core of the Indochina Block. The West

  11. Development of eddy current testing probe for thick-walled metal plate and quantitative evaluation of cracks

    CERN Document Server

    Sato, K; Uchimoto, T; Takagi, T

    2003-01-01

    This paper demonstrates the crack detection of thick-walled non-magnetic metal plates by eddy current testing, which is difficult because of Kelvin skin effect generally. The purpose of this research is the development of an new eddy current testing probe for cracks in thick-walled plates and crack shapes quantitative evaluation. The probe was designed, based on the numerical computation using 3D fast eddy current code. The advantages of this new probe are strong eddy current on the back of specimens and gentle decrement of eddy current in the thickness direction. Through experiments, we confirmed that this probe can detect the back artificial defect with 0.5 mm thickness on IN-CONEL 718 specimen with 7.0 mm thickness. Reconstruction of crack shapes was performed based on the experimental results with the inverse problem code developed by authors. The length and depth of reconstructed defects approximately agree with those of real crack. (author)

  12. Shrinkage Analysis on Thick Plate Part using Response Surface Methodology (RSM

    Directory of Open Access Journals (Sweden)

    Isafiq M.

    2016-01-01

    Full Text Available The work reported herein is about an analysis on the quality (shrinkage on a thick plate part using Response Surface Methodology (RSM. Previous researches showed that the most influential factor affecting the shrinkage on moulded parts are mould and melt temperature. Autodesk Moldflow Insight software was used for the analysis, while specifications of Nessei NEX 1000 injection moulding machine and P20 mould material were incorporated in this study on top of Acrylonitrile Butadiene Styrene (ABS as a moulded thermoplastic material. Mould temperature, melt temperature, packing pressure and packing time were selected as variable parameters. The results show that the shrinkage have improved 42.48% and 14.41% in parallel and normal directions respectively after the optimisation process.

  13. Calibrated expressions for welding and their application to isotherm width in a thick plate

    Directory of Open Access Journals (Sweden)

    Gentry Wood

    2014-09-01

    Full Text Available The present paper introduces a possible solution to the limitations of modern trial and error solutions to welding procedure development. The difficulties of finding generalized solutions to Rosenthal´s equation are discussed and the Minimal Representation and Calibration approach is introduced as a promising procedure for developing these solutions. Dominant factors are identified, with effects from secondary phenomena being taken into account by correction factors. These correction factors are then calibrated and presented in a form that can be easily computed, and therefore be amendable to industry. The approach is then demonstrated by determining the isotherm width from Rosenthal´s thick plate solution. Comparison of the calibrated scaling equations to Rosenthal´s exact solution showed a maximum error of less than 0.8% for any isotherm.

  14. Manufacturing of aluminum alloy ultra-thick plates by multidirectional forging and subsequent rolling

    Institute of Scientific and Technical Information of China (English)

    张辉; 林高用; 彭大暑; 杨立斌; 林启权

    2002-01-01

    A combinatory large deformation model of multidirectional forging and subsequent rolling was proposed for producing high performance aluminum alloy ultra-thick plates.The results show that fine-grain (2~3 μm) structures were obtained when total deformation coefficient λ =32 at 250~350 ℃ under a strain rate of about 0.1 s-1.The development of fine-grained structure can be characterized by the formation of strain-induced high energy dislocation and then transforms into new grain under large deformation at moderate temperature.The very fine secondary particles formed during large deformation play important role in retain the stability of the fine-grained structures.

  15. Phase-conjugate interferometer to estimate refractive index and thickness of transparent plane parallel plates

    Energy Technology Data Exchange (ETDEWEB)

    Pastrana-Sanchez, R.; Rodriguez-Zurita, G.; Vazquez-Castillo, J. F. [Benemerita Universidad Autonoma de Puebla, Puebla (Mexico)

    2001-04-01

    A technique to estimate the refractive index and thickness of homogeneous plane parallel dielectric plates is proposed using a phase-conjugate interferometer, in which counting of interference fringes is employed. The light beam impinges a tilted plate before it enters a phase-conjugate interferometer, and a count of the fringes passing through a given reference at the observing plane gives the phase changes as a function of tilting angle. The obtained data is fitted to a mathematical model, which leads to the determination of both refractive index and thickness simultaneously. In this letter, experimental data from two interferometers are also discussed for comparison. One with an externally-pumped phase-conjugate mirror achieved with a BSO photorefractive crystal and another one with conventional mirrors. Results show that the phase sensitivity of the phase-conjugate interferometer is not simply twice the corresponding sensitivity of the conventional version. [Spanish] Se propone una tecnica para medir indices de refraccion y espesores de placas dielectricas plano paralelas homogeneas empleando un interferometro con fase conjugada, en el cual se usa el conteo de franjas. El haz luminoso incide en una placa inclinada bajo inspeccion antes de entrar en un interferometro equipado con un espejo conjugador de fase, y se realiza un conteo de las franjas que pasan por determinada referencia en el plano de observacion, proporcionando los cambios de fase en funcion del angulo de inclinacion. Los datos obtenidos se ajustan a un modelo, el cual conduce a la determinacion, tanto del indice de refraccion como del espesor, simultaneamente. En este trabajo se discuten datos experimentales provenientes de dos interferometros para su comparacion. Uno de ellos tiene un espejo conjugador basado en un cristal BSO fotorrefractivo, mientras que el otro es una variante con espejos convencionales. Se muestra que la sensibilidad de fase del interferometro con conjugador de fase no

  16. Optimal rectangular plate and shallow shell topologies using thickness distribution or homogenization

    Science.gov (United States)

    Tenek, Lazarus H.; Hagiwara, Ichiro

    1994-05-01

    Topological optimization of plates, as well as shallow cylindrical and curved (spherical) shells, are attempted in the present study. For all structures examined, our objective is the minimization of the strain energy function under a volume constraint. An optimum distribution of thickness or microstructural density is sought under the hypothesis that the design variables can only be assigned their extreme allowable bounds, or values very near them, so that material can be removed from low density areas and thus, an optimum topology can be determined. The structural response is computed via a finite element analysis. The analytical formulation is based on a form of linear shallow shell theory with the effects of transverse shear deformation and bending-extensional coupling included. The method of feasible directions is used to perform the optimization task. Numerical examples for various boundary conditions showing similarities or differences of the two methods are presented and discussed. For all structures examined, it is found that the assumption of a repetitious microstructure based on homogenization theory resulted in stronger optima. For clamped plates and shells, both methods converged to nearly identical topologies, an indication of possible global optimal layouts.

  17. Free Transverse Vibration of Orthotropic Thin Trapezoidal Plate of Parabolically Varying Thickness Subjected to Linear Temperature Distribution

    Directory of Open Access Journals (Sweden)

    Arun Kumar Gupta

    2014-01-01

    Full Text Available The present paper deals with the free transverse vibration of orthotropic thin trapezoidal plate of parabolically varying thickness in x-direction subjected to linear temperature distribution in x-direction through a numerical method. The deflection function is defined by the product of the equations of the prescribed continuous piecewise boundary shape. Rayleigh-Ritz method is used to evaluate the fundamental frequencies. The equations of motion, governing the free transverse vibrations of orthotropic thin trapezoidal plates, are derived with boundary condition CSCS. Frequency corresponding to the first two modes of vibration is calculated for the orthotropic thin trapezoidal plate having CSCS edges for different values of thermal gradient, taper constant, and aspect ratio. The proposed method is applied to solve orthotropic thin trapezoidal plate of variable thickness with C-S-C-S boundary conditions. Results are shown by figures for different values of thermal gradient, taper constant, and aspect ratio for the first two modes of vibrations.

  18. The influence of nitride thickness variations on the switching speed of MNOS memory transistors

    DEFF Research Database (Denmark)

    Bruun, Erik

    1978-01-01

    The influence of nitride thickness variations on the switching speed of MNOS memory transistors is examined. The switching time constant is calculated as a function of the nitride thickness using a model of modified Fowler-Nordheim injection. The calculated characteristics compare well with measu......The influence of nitride thickness variations on the switching speed of MNOS memory transistors is examined. The switching time constant is calculated as a function of the nitride thickness using a model of modified Fowler-Nordheim injection. The calculated characteristics compare well...

  19. 3D electroplated inductors with thickness variation for improved broadband performance

    Science.gov (United States)

    Farm-Guoo Tseng, Victor; Bedair, Sarah S.; Lazarus, Nathan

    2017-01-01

    The performance of an RF spiral inductor is based on the balance between ohmic losses in the outer turns and eddy current losses dominant in the inner turns where the magnetic field is the strongest. In this work, air-core spiral inductors with winding trace thicknesses decreasing towards the center are demonstrated, achieving quality factor improvement over a wide frequency range compared to uniform thickness inductors. A custom 3D copper electroplating process was used to produce spiral inductors with varying winding thicknesses in a single plating step, with patterned gaps in a seed layer used to create delays in the vertical plating. The fabricated center-lowered coil inductors were 80 nH within a one square millimeter area with thickness varying from 60 µm to 10 µm from outer to inner winding. Within the 16 MHz-160 MHz range, the center-lowered inductors were shown to have a maximum to minimum quality factor improvement of 90%-10% when compared to uniform thickness inductors with thicknesses ranging from 60 µm to 10 µm. Compared to the 20 µm uniform thickness inductor which has the optimal performance among all uniform thickness inductors in this frequency range, the center-lowered inductors were shown to achieve a maximum quality factor improvement of 20% at the edge frequencies of 16 MHz and 160 MHz, and a minimum quality factor improvement of 10% near the geometric mean center frequency of 46 MHz.

  20. Optical thickness measurement of mask blank glass plate by the excess fraction method using a wavelength-tuning interferometer

    Science.gov (United States)

    Kim, Yangjin; Hibino, Kenichi; Sugita, Naohiko; Mitsuishi, Mamoru

    2013-10-01

    The absolute optical thickness of a 140-mm2 mask blank glass plate 3.1 mm thickness was measured by three-surface interferometry using a wavelength-tuning Fizeau interferometer. The interference order was determined by the excess fraction method. The wavelength of a tunable laser diode was scanned linearly from 632 to 642 nm, and a CCD detector recorded 2000 interference images. Two kinds of optical thicknesses measured by discrete Fourier analysis and phase-shifting were synthesized to obtain the optical thickness with respect to the ordinary refractive index. The optical thickness defined by the group refractive index at the 637 nm central wavelength was measured by wavelength scanning. The optical thickness deviation defined by the ordinary refractive index was measured using tunable phase-shifting. The systematic errors caused by nonlinearity in the wavelength tuning were corrected through correlation analysis between the theoretical and observed interference fringes.

  1. Laser-Assisted Stir Welding of 25-mm-Thick HSLA-65 Plate

    Science.gov (United States)

    Williamson, Keith M.

    2002-12-01

    Laser-assisted stir welding is a hybrid process that combines energy from a laser with functional heating and mechanical energy to join materials in the solid state. The technology is an adaptation of friction stir welding which is particularly suited for joining thick plates. Aluminum plates up to 75 mm thick have been successfully joined using friction stir welding. Since joining occurs in the solid state, stir technology offers the capability for fabricating full penetration joints in thick plates with better mechanical properties and less weld distortion than is possible by fusion processes. Currently friction stir welding is being used in several industries to improve productivity, reduce weight, and increase the strength of welded structures. Examples include: (a) the aircraft/aerospace industry where stir technology is currently being used to fabricate the space shuttle's external tank as well as components of the Delta family of rockets; (b) the shipping industry where container manufacturers are using stir technology to produce lighter containers with more payload capacity; and (c) the oil industry where offshore platform manufactures are using automated stir welding plants to fabricate large panels and structures up to 16 meters long with widths as required. In all these cases, stir technology has been restricted to aluminum alloys; however, stainless and HSLA 65 steels have been recently stir welded with friction as the primary heat source. One of the difficulties in adapting stir welding to steel is tool wear aggravated by the high tool rubbing velocities needed to provide frictional heat input into the material. Early work showed that the tool shoulder reached temperatures above 1000 C and the weld seam behind the tool stayed within this temperature range for up to 25 mm behind the tool. Cross sections of stir welded samples showed that the heat-affected zone is relatively wide and follows the profile of the tool shoulder. Besides minimizing the tool

  2. Clad thickness variation N-Reactor fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Smith, E.A.

    1966-05-12

    The current specifications for the cladding on {open_quotes}N{close_quotes} fuels were established early in the course of process development and were predicted on several basic considerations. Among these were: (a) a desire to provide an adequate safety factor in cladding thickness to insure against corrosion penetration and rupture from uranium swelling stresses; (b) an apprehension that the striations in the zircaloy cladding of the U/zircaloy interface and on the exterior surface might serve as stress-raisers, leading to untimely failures of the jacket; and (c) then existing process capability - the need to maintain a specified ratio between zircaloy and uranium in the billet assembly to effect satisfactory coextrusion. It now appears appropriate to review these specifications in an effort to determine whether some of them may be revised, with attendant gains in economy and/or operating smoothness.

  3. Effect of glass thickness variation on the performance of RPC detectors

    CERN Document Server

    Sadiq, Jafar; Behera, Prafulla Kumar

    2016-01-01

    The India-based Neutrino Observatory(INO) is planning to build a magnetized iron calorimeter detector (ICAL) in which Resistive Plate Chambers(RPCs) will be the active detector elements. Study of the performance of RPC detectors of varying glass thickness is pivotal in optimizing the design parameters of the ICAL RPCs. We fabricated RPCs with glasses of varying thickness and studied their performance in the same ambient conditions. The study of detector efficiency, noise rate, time resolution and charge resolution is presented in this paper. We have observed that the knee voltage of the RPC varies with the thickness of the glass electrode.

  4. Influence of CrN-coating thickness on the corrosion resistance behaviour of aluminium-based bipolar plates

    Science.gov (United States)

    Barranco, José; Barreras, Félix; Lozano, Antonio; Maza, Mario

    The electrical and corrosion properties of CrN-coated aluminium alloy Magnal-45 (Al-5083) probes have been evaluated, in order to assess their viability to be used as bipolar plates in polymer electrolyte fuel cells. To this end, ceramic micro-layers of chromium nitride (CrN) with different thicknesses (3, 4, and 5 μm) have been deposited on the surface of the Al alloy (Al-5083) using the physical vapour deposition (PVD) technique. A decrease in 2 orders of magnitude of I corr values for the coated Al has been observed compared to the as-received Al-alloy when the probes have been exposed to simulated anodic conditions in a micro-reactor. On the other hand, when subjected to a cathodic-simulated environment, the Al-CrN probes with 3 μm and 4 μm coatings have shown a decrease in I corr of one order of magnitude, while a variation of two orders of magnitude has also been obtained for the 5 μm coating.

  5. Variational Stability Form for the Capacitance of an Arbitrarily Shaped Conducting Plate

    Institute of Scientific and Technical Information of China (English)

    LIANGChanghong; LILong; ZHAIHuiqing

    2004-01-01

    A new analytical method for finding the capacitance of an arbitrarily shaped conducting plate is presented in this paper. If the charge density suitable to fringe conditions and the appropriate charge barycenter are supposed, the variational stability form with high accuracy for the capacitance C can be achieved by simple curve integrals or the superposition of basic triangles. In this paper, some analytical examples such as an elliptical plate, a regular polygonal plate and a rectangular plate are given. It is worth pointing out that the analytical closed-form for an elliptical plate is accurate. Comparing the result of the analytical closed-form for the square plate and the numerical result of Richardson's extrapolation, the relative error is less than 1.7%. Furthermore, the relationship between the charge barycenter and the variational stability is discussed.

  6. Thick shell tectonics on one-plate planets - Applications to Mars

    Science.gov (United States)

    Banerdt, W. B.; Saunders, R. S.; Phillips, R. J.; Sleep, N. H.

    1982-01-01

    Using the zero frequency equations of a self-gravitating elastic spherical shell overlying a strengthless fluid, a theory for stress distribution in thick lithospheric shells on one-plate planets is developed. For both the compensated and flexural modes, stress distributions in lithospheres are reviewed. For compensated modes, surface stresses depend only on surface topography, whereas for flexural modes it is shown that, for long wavelengths, stress trajectories are mainly dependent on the lithospheric lateral density distribution and not on elastic properties. Computational analyses are performed for Mars, and it is found that isostatically compensated models correctly predict the graben structure in the immediate Tharsis region and a flexural loading model is satisfactory in explaining the graben in the regions surrounding Tharsis. A three-stage model for the evolution of Tharsis is hypothesized: isostasy with north-south graben formation on Tharsis, followed by flexural loading and radial graben formation on the perimeter of Tharsis, followed by a last stage of loading with little or no regional deformation.

  7. Influences of processing routine on mechanical properties and structures of 7075 aluminum alloy thick-plates

    Institute of Scientific and Technical Information of China (English)

    林高用; 张辉; 张行健; 韩冬峰; 张颖; 彭大暑

    2003-01-01

    7075 aluminum alloy thick-plates were produced by three processing routines: commercial hot-rolling followed by heat treatment of quenching and ageing (HR+QA), combination of large deformation processing of multi-directional warm forging and subsequent warm rolling followed by heat treatment of quenching and ageing (LD+QA), and that followed by annealing at moderate temperature (LD+AN). Tensile strength, yield strength and elongation were measured by tension test, and the metallographic structures were examined by optical microscopy (OM) and transmission electron microscopy (TEM), also the fracture morphologies were observed by scanning electron microscopy (SEM). It is shown that higher tensile strength and yield strength are obtained from (LD+QA) processing in comparison with those from (HR+QA) and (LD+AN) processings. Tensile strength and yield strength obtained from (LD+QA) processing are 9.9% and 8.6% higher respectively than those from (HR+QA) processing, and 48.6% and 57.7% higher respectively than those from (LD+AN) processing; while the elongations of all the samples show no significant difference and keep 10%-12%. Analyses of OM and TEM reveal that the mechanical behaviors are deeply associated with the formation of refined structures with fine grains and very fine precipitates, leading to fine-grained hardening and excellent age hardening.

  8. Numerical simulation of full-penetration laser beam welding of thick aluminium plates with inductive support

    Science.gov (United States)

    Bachmann, Marcel; Avilov, Vjaceslav; Gumenyuk, Andrey; Rethmeier, Michael

    2012-01-01

    A three-dimensional laminar steady-state numerical model was developed to investigate the influence of an alternating current (ac) magnetic field during high-power full-penetration laser welding on the weld pool dynamics and weld cross section of a 20 mm thick aluminium plate in flat position. Three-dimensional heat transfer, fluid dynamics including phase transition and electromagnetic field partial differential equations were solved iteratively with the commercial finite element software COMSOL Multiphysics using temperature-dependent material properties up to evaporation temperature. Thermocapillary convection at the weld pool surfaces, natural convection and latent heat of solid-liquid phase transition were taken into account in this model. Solidification was modelled by the Carman-Kozeny equation for porous media morphology. The ac magnet was mounted on the root side of the weld specimen. The magnetic field was aligned perpendicular to the welding direction. The flow pattern in the melt and thus also the temperature distribution were significantly changed by the application of oscillating magnetic fields. It was shown that the application of an ac magnetic field to laser beam welding allows for a prevention of the gravity drop-out. The simulation results are in good qualitative agreement with the experimental observations.

  9. Thick shell tectonics on one-plate planets - Applications to Mars

    Science.gov (United States)

    Banerdt, W. B.; Saunders, R. S.; Phillips, R. J.; Sleep, N. H.

    1982-01-01

    Using the zero frequency equations of a self-gravitating elastic spherical shell overlying a strengthless fluid, a theory for stress distribution in thick lithospheric shells on one-plate planets is developed. For both the compensated and flexural modes, stress distributions in lithospheres are reviewed. For compensated modes, surface stresses depend only on surface topography, whereas for flexural modes it is shown that, for long wavelengths, stress trajectories are mainly dependent on the lithospheric lateral density distribution and not on elastic properties. Computational analyses are performed for Mars, and it is found that isostatically compensated models correctly predict the graben structure in the immediate Tharsis region and a flexural loading model is satisfactory in explaining the graben in the regions surrounding Tharsis. A three-stage model for the evolution of Tharsis is hypothesized: isostasy with north-south graben formation on Tharsis, followed by flexural loading and radial graben formation on the perimeter of Tharsis, followed by a last stage of loading with little or no regional deformation.

  10. Wall thickness variation effect on tank’s shape behaviour under critical harmonic settlement

    Directory of Open Access Journals (Sweden)

    Ahmed Shamel Fahmy

    2016-12-01

    Full Text Available The purpose of this study was to investigate the effect of wall thickness variation on tank’s wall buckling mode under the effect of critical harmonic settlement for open top tanks. The study was performed on four tanks which have the same geometric and material properties except wall thickness, for each case the tank was subjected to several settlement waves which has the same settlement amplitude, and the buckling mode and critical vertical settlement results were compared. For buckling mode, the results show that tanks with wall thickness at a close range have similar buckling mode behaviour and in case using too thick wall the buckling mode starts to change. And for the effect on critical vertical settlement, the results show that vertical settlement is sensitive to any variation in wall thickness beside that settlement value changes with the effected wave number and this variation could change the whole behaviour of the tanks. The study recommended that in case of performing analysis for a tank with neglecting the variation in wall thickness values, the value of chosen wall thickness should be the average of wall thickness values obtained from the designed equation.

  11. The importance of temporal stress variation and dynamic disequilibrium for the initiation of plate tectonics

    Science.gov (United States)

    Stamenković, V.; Höink, T.; Lenardic, A.

    2016-06-01

    We use 1-D thermal history models and 3-D numerical experiments to study the impact of dynamic thermal disequilibrium and large temporal variations of normal and shear stresses on the initiation of plate tectonics. Previous models that explored plate tectonics initiation from a steady state, single plate mode of convection concluded that normal stresses govern the initiation of plate tectonics, which based on our 1-D model leads to plate yielding being more likely with increasing interior heat and planet mass for a depth-dependent Byerlee yield stress. Using 3-D spherical shell mantle convection models in an episodic regime allows us to explore larger temporal stress variations than can be addressed by considering plate failure from a steady state stagnant lid configuration. The episodic models show that an increase in convective mantle shear stress at the lithospheric base initiates plate failure, which leads with our 1-D model to plate yielding being less likely with increasing interior heat and planet mass. In this out-of-equilibrium and strongly time-dependent stress scenario, the onset of lithospheric overturn events cannot be explained by boundary layer thickening and normal stresses alone. Our results indicate that in order to understand the initiation of plate tectonics, one should consider the temporal variation of stresses and dynamic disequilibrium.

  12. Influence of relative rolling reduction and thickness layers bimetallic plate at the non-uniformity of the strain after rolling process

    Science.gov (United States)

    Rydz, D.; Stradomski, G.; Dyja, H.

    2017-02-01

    In the article were made numerical and laboratory tests of two-layers rolling process sheet composed of Al99,8 + M1E. Laboratory tests made with use of 150 mm diameter working rolls mill. To the modeling of the bimetallic plate rolling were taken the FEM Forge 2D software based on the theory of plasticity and MathCad program (in which to the rolling process modeling were used the mathematical model developed in the work [5] based on the theory of viscoelasticity). The aim of study was to determine the influence of layer thickness HT0/HM0 and relative deformation ε on the uneven distribution of steel sheet deformation after rolling process. Calculations based on the theory of viscoelasticity allowed additionally take into account the impact of the delayed effects of the variation of viscoelastic deformation of layers of the bimetallic plate rolling process.

  13. Non-destructive evaluation of the cladding thickness in LEU fuel plates by accurate ultrasonic scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Borring, J.; Gundtoft, H.E.; Borum, K.K.; Toft, P. [Riso National Lab. (Denmark)

    1997-08-01

    In an effort to improve their ultrasonic scanning technique for accurate determination of the cladding thickness in LEU fuel plates, new equipment and modifications to the existing hardware and software have been tested and evaluated. The authors are now able to measure an aluminium thickness down to 0.25 mm instead of the previous 0.35 mm. Furthermore, they have shown how the measuring sensitivity can be improved from 0.03 mm to 0.01 mm. It has now become possible to check their standard fuel plates for DR3 against the minimum cladding thickness requirements non-destructively. Such measurements open the possibility for the acceptance of a thinner nominal cladding than normally used today.

  14. Free asymmetric transverse vibration of polar orthotropic annular sector plate with thickness varying parabolically in radial direction

    Indian Academy of Sciences (India)

    R P Singh; S K Jain

    2004-10-01

    In the present paper, free asymmetric transverse vibrations of a nonuniform polar orthotropic annular sector plate, with parabolically varying thickness in the radial direction, have been studied on the basis of classical plate theory. The circular edges of the plate are elastically restrained against translation and rotation while the straight (radial) edges are simply-supported. Fourth-order linear differential equations with variable coefficients governing the motion have been solved by using the collocation interpolation technique with Chebyshev points as the interpolating nodes. Frequency parameters of the plate with flexible boundary conditions at the circular edges for some typical values of the taper parameters, the rigidity ratios and the radii ratio have been presented.

  15. Solving the problem of elasticity for round thick plates at axially symmetric strain

    Directory of Open Access Journals (Sweden)

    Oleksiy Hvertsev

    2016-12-01

    Full Text Available An exact solution of the equations of elasticity for round plates loaded axially symmetric. The problem of bending round plates, which are under the influence of normal forces attached to any law to load any type of resistance. It is shown that pasture circular plate under axially symmetric load leads to appearance of temperature field.

  16. Development of automated welding processes for field fabrication of thick-walled pressure vessels: electron beam method. Seventh quarterly report, April 1-June 30, 1979. [8-in. thick 2 1/4 Cr-1 Mo plate

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.M.

    1979-01-01

    A total of 449 experimental welds have been made to date. Partial penetration welding procedures capable of producing defect-free, 4-inch deep welds have been developed in the horizontal position. The travel speed that can be acceptably used for partial penetration welding of 2 1/4 Cr-1 Mo is larger for 6-inch thick plate than for 8-inch thick plate. Although defect-free welds can be made with soft vacuum conditions, hard vacuum conditions produce the most reliable performance. A procedure for welding an 8-inch thick joint has been developed. A small test plate was welded, radiographed, and cross sectioned and found to be acceptable. A large 8-inch thick test plate was welded and found to contain porosity. Difficulties in uniformly moving this large plate appear to be responsible for the porosity encountered. A mechanical modification to the welding equipment is being made and the large plate will be welded again. 3 figures.

  17. Effect of Backing Plate Thermal Property on Friction Stir Welding of 25-mm-Thick AA6061

    Science.gov (United States)

    Upadhyay, Piyush; Reynolds, Anthony

    2014-04-01

    By using backing plates made out of materials with widely varying thermal diffusivity this work seeks to elucidate the effects of the root side thermal boundary condition on weld process variables and resulting joint properties. Welds were made in 25.4-mm-thick AA6061 using ceramic, titanium, steel, and aluminum as backing plate (BP) material. Welds were also made using a "composite backing plate" consisting of longitudinal narrow strip of low diffusivity material at the center and two side plates of high diffusivity aluminum. Stir zone temperature during the welding was measured using two thermocouples spot welded at the core of the probe: one at the midplane height and another near the tip of the probe corresponding to the root of the weld. Steady state midplane probe temperatures for all the BPs used were found to be very similar. Near root peak temperature, however, varied significantly among weld made with different BPs all other things being equal. Whereas the near root and midplane temperature were the same in the case of ceramic backing plate, the root peak temperature was 318 K (45 °C) less than the midplane temperature in the case of aluminum BP. The trends of nugget hardness and grain size in through thickness direction were in agreement with the measured probe temperatures. Hardness and tensile test results show that the use of composite BP results in stronger joint compared to monolithic steel BP.

  18. High power laser welding of thick steel plates in a horizontal butt joint configuration

    Science.gov (United States)

    Atabaki, M. Mazar; Yazdian, N.; Ma, J.; Kovacevic, R.

    2016-09-01

    In this investigation, two laser-based welding techniques, autogenous laser welding (ALW) and laser welding assisted with a cold wire (LWACW), were applied to join thick plates of a structural steel (A36) in a horizontal narrow gap butt joint configuration. The main practical parameters including welding method and laser power were varied to get the sound weld with a requirement to achieve a full penetration with the reinforcement at the back side of weld in just one pass. The weld-bead shape, cross-section and mechanical properties were evaluated by profilometer, micro-hardness test and optical microscope. In order to investigate the stability of laser-induced plasma plume, the emitted optical spectra was detected and analyzed by the spectroscopy analysis. It was found that at the laser power of 7 kW a fully penetrated weld with a convex back side of weld could be obtained by the LWACW. The microstructural examinations showed that for the ALW the acicular ferrite and for the LWACW the pearlite were formed in the heat affected zone (HAZ). The prediction of microstructure based on continuous cooling transformation (CCT) diagram and cooling curves obtained by thermocouple measurement were in good agreement with each other. According to the plasma ionization values obtained from the spectroscopy analysis the plume for both processes was recognized as dominated weakly ionized plasma including the main vaporized elemental composition. At the optimum welding condition (LWACW at the laser power of 7 kW) the fluctuation of the electron temperature was reduced. The spectroscopy analysis demonstrated that at the higher laser power more of the elemental compositions such as Mn and Fe were evaporated.

  19. Regional variations in the nature of the incoming plate and its implication to the subduction zone

    Science.gov (United States)

    Fujie, Gou; Kodaira, Shuichi; Obana, Koichiro; Kaiho, Yuka; Sato, Takeshi; Yamamoto, Yojiro; Takahashi, Tsutomu; Miura, Seiichi; Yamada, Tomoaki

    2017-04-01

    The megathrust earthquakes like the 2011 Tohoku earthquake are caused by the interaction between the overlying plate and the subducting oceanic plate, indicating that the properties of the subducing oceanic plate, such as their geometry, thermal state, lithology, and water content, have a potential to controll the megathrust earthquakes. Of these properties, water content (degree of hydration) is highly influential because water transported by the incoming plate lowers the temperature of the subduction zone, promotes forearc metamorphism. Moreover, the presence of water and hydrated materials like serpentine can affect interplate seismic coupling on the plate interface. Accordingly, the regional variations in the degree of the hydration within the incoming plate might have strong influences on the regional variations in the interplate earthquakes. To reveal the regional variations in the nature of the incoming oceanic plate and its evolution owing to bending-related faulting near the trench axis, we conducted extensive controlled-source seismic surveys in the trench-outer rise region off northeastern Japan arc. We confirmed the systematic changes in seismic velocities owing to the bending-realated faulting, suggesting the water content within the incoming oceanic plate increases toward the trench accompanied by the development of bending-related fractures. In addition, we found along-trench variations in the seismic structure of the incoming oceanic plate; lower seismic velocities and higher Vp/Vs ration around the ancient fracture zones associated with ridge propagation. This observation suggests that the ancient scar on the oceanic plate influences along-trench variations in the current water amount transported by the oceanic plate. If we extend the ancient fracture zone toward the forearc region, it corresponds to an area of weak interplate coupling, characterized by low Vp and high Vp/Vs ratio around the depth of the plate interface. Our observations suggest

  20. Thickness Determination for a Two-Layered Composite of a Film and a Plate by Low-Frequency Ultrasound

    Institute of Scientific and Technical Information of China (English)

    MAO Jie; LI Ming-Xuan; WANG Xiao-Min

    2007-01-01

    We present an ultrasonic method for determining the thickness of a composite consisting of a soft thin film attached to a hard plate substrate, by resonance spectra in the low frequency region. The interrogating waves can be incident only to the two-layered composite from the substrate side. The reflection spectra are obtained by FFT analysis of the compressive pulsed echoes from the composite, and the thicknesses of the film and the substrate are simultaneously inversed by the simulated annealing method from the resonant frequencies knowing other acoustical parameters in prior. The sensitivity of the method to individual thickness, its convergence and stability against experimental noises are studied. Experiment with interrogating wavelength 4 times larger than the film thickness in a sample of a polymer film (0.054 mm) on an aluminium plate (6.24 mm) verifies the validity of the method. The average relative errors in the measurement of the thicknesses of the film and the substrate are found to be -4.1% and -0.62%, respectively.

  1. Acoustic radiation from out-of-plane modes of an annular disk using thin and thick plate theories

    Science.gov (United States)

    Lee, Hyeongill; Singh, Rajendra

    2005-04-01

    Out-of-plane (flexural) vibration is a major source of sound radiation from many mechanical or structural components having annular or circular disk shape. The typical thickness of practical components is often beyond the thin plate theory limit and it may have considerable effect on sound radiation. But, traditionally, thin annular disk models have been employed for such structures neglecting the thickness effect. In this article, structural eigensolutions for the out-of-plane modes and sound radiation from the modal vibration of a thick annular disk with free-free boundaries have been calculated using both thick and thin plate theories. A new analytical formulation is proposed for the sound radiation problem. In addition, the same problem has been solved by a semi-analytical procedure in which the disk surface velocity is numerically defined by a finite-element model and sound radiation is then analytically obtained using a modified circular radiator model. Also, the effects of radii and thickness ratios on the structural and acoustic radiation characteristics are investigated using the analytical procedure. Finally, the effect of boundary conditions is briefly examined.

  2. Research on parameters optimization of bilateral ring gear blank-holder in thick-plate fine blanking

    Directory of Open Access Journals (Sweden)

    C.J.Su

    2014-10-01

    Full Text Available To compensate for the poor quality of thick-plate blanking parts in cross-section, this paper suggests using the optimizing bilateral ring gear holder parameters to increase burnish zone and improve cutting precision. With the bilateral gear ring, the hydrostatic pressure of shear deformation zone will increase, plasticity of the material will be lifted to maximum and quality of the cross section will be raised. This paper establishes 8mm AISI-1020 fine blanking model by DEFORM2D, analysis different ring gear parameters and clearance that are influenced the stress-strain and cross section quality to predict forming defects. By using the bilateral gear ring blank holder, the poor quality of thick-plate blanking section is successfully enhanced. Therefore, the bilateral gear ring blank holder is vital to improve the quality of blanking parts and provide the reliable theory basis for the practical engineering application.

  3. BASIC EQUATIONS OF THE PROBLEM OF THE NONLINEAR UNSYMMETRICAL BENDING FOR ORTHOTROPIC RECTANGULAR THIN PLATE WITH VARIABLE THICKNESS

    Institute of Scientific and Technical Information of China (English)

    黄家寅

    2004-01-01

    Under the case of ignoring the body forces and considering components caused by diversion of membrane in vertical direction ( z-direction ), the constitutive equations of the problem of the nonlinear unsymmetrical bending for orthotropic rectangular thin plate with variable thickness are given; then introducing the dimensionless variables and three small parameters, the dimensionaless governing equations of the deflection function and stress function are given.

  4. Through-Thickness Variations of Deformed and Annealed Microstructures in ECAE-Processed Copper

    DEFF Research Database (Denmark)

    Mishin, Oleg; Bowen, Jacob R.

    2009-01-01

    Through-thickness variations of the microstructure in copper processed using equal channel angular extrusion (ECAE) to a strain of ~10 without rotations between passes have been investigated in deformed and partially recrystallized conditions. It is found that the through-thickness heterogeneity...... strain. Compared to other inspected layers the bottom part of the billet was less refined after ECAE and remained less recrystallized after annealing....

  5. Evaluation of paint coating thickness variations based on pulsed Infrared thermography laser technique

    Science.gov (United States)

    Mezghani, S.; Perrin, E.; Vrabie, V.; Bodnar, J. L.; Marthe, J.; Cauwe, B.

    2016-05-01

    In this paper, a pulsed Infrared thermography technique using a homogeneous heat provided by a laser source is used for the non-destructive evaluation of paint coating thickness variations. Firstly, numerical simulations of the thermal response of a paint coated sample are performed. By analyzing the thermal responses as a function of thermal properties and thickness of both coating and substrate layers, optimal excitation parameters of the heating source are determined. Two characteristic parameters were studied with respect to the paint coating layer thickness variations. Results obtained using an experimental test bench based on the pulsed Infrared thermography laser technique are compared with those given by a classical Eddy current technique for paint coating variations from 5 to 130 μm. These results demonstrate the efficiency of this approach and suggest that the pulsed Infrared thermography technique presents good perspectives to characterize the heterogeneity of paint coating on large scale samples with other heating sources.

  6. 4D segmentation of brain MR images with constrained cortical thickness variation.

    Directory of Open Access Journals (Sweden)

    Li Wang

    Full Text Available Segmentation of brain MR images plays an important role in longitudinal investigation of developmental, aging, disease progression changes in the cerebral cortex. However, most existing brain segmentation methods consider multiple time-point images individually and thus cannot achieve longitudinal consistency. For example, cortical thickness measured from the segmented image will contain unnecessary temporal variations, which will affect the time related change pattern and eventually reduce the statistical power of analysis. In this paper, we propose a 4D segmentation framework for the adult brain MR images with the constraint of cortical thickness variations. Specifically, we utilize local intensity information to address the intensity inhomogeneity, spatial cortical thickness constraint to maintain the cortical thickness being within a reasonable range, and temporal cortical thickness variation constraint in neighboring time-points to suppress the artificial variations. The proposed method has been tested on BLSA dataset and ADNI dataset with promising results. Both qualitative and quantitative experimental results demonstrate the advantage of the proposed method, in comparison to other state-of-the-art 4D segmentation methods.

  7. A Study of the Effect of Gold Thickness Distribution in the Jet Plating Process to Optimize Gold Usage and Plating Voltage Using Design of Experiments

    OpenAIRE

    Aramphongphun Chuckaphun; Nampanya Chalermpol

    2016-01-01

    A gold plating process in the electronics industry can be classified as (i) all surface plating or (ii) selective plating. Selective plating is more widely used than all surface plating because it can save more gold used in the plating process and takes less plating time. In this research, the selective plating process called jet plating was studied. Factors that possibly affected the gold usage and plating voltage were also studied to reduce the production cost. These factors included (a) pl...

  8. Gold plating on spectacle frames.

    Science.gov (United States)

    Kenny, I; Mitchell, J W; Walsh, G

    1997-05-01

    An investigation was carried out into the thickness and standard of application of the plating and lacquer coatings applied to three metal spectacle frames. All conform to BS 6625 (1991) for plating thickness, but there was considerable variation in regularity and porosity.

  9. Natural Variation of Leaf Thickness and Its Association to Yield Traits in indica Rice

    Institute of Scientific and Technical Information of China (English)

    LIU Chuan-guang; ZHOU Xin-qiao; CHEN Da-gang; LI Li-jun; LI Ju-chang; CHEN You-ding

    2014-01-01

    Leaf thickness is an important morphological trait in rice. Its association to the yield potential, as of now has not been documented because of the shortage of the equipment which could conveniently measure the leaf thickness in rice. In this study, the thickness of top three leaves of 208 cultivars had been determined by a nondestructive rice leaf thickness instrument for the research of the natural variation of leaves thickness and its association to yield traits inindica rice. The results showed that the lfag leaf was the thickest, and the 2nd leaf was thicker than the 3rd leaf. Analysis of variance indicated the existence of wide genetic diversity of leaf thickness among the investigatedindica rice genotypes. The tight correlation among the thicknesses of the top three leaves means that the leaf thickness traits share one genetic control system. Leaf thickness had a signiifcant positive correlation with leaf length and a positive correlation with leaf width, indicated that thicker leaf was beneifcial to increasing the single leaf area. The results of correlation analysis revealed that thicker leaf should be proiftable to the leaf erection, higher numbers of grains per panicle and higher grains weight per panicle. However, the signiifcantly negative correlation between leaf thickness and number of panicles per plant counteracted the proiftability from increased grains weight per panicle, so that the correlations of the thicknesses of the top three leaves to yield and biomass were positive but not signiifcantly. It has made great progress in the genetic improvement of leaves thickness in inbredindica rice breeding in Guangdong Province, China, since the 1990s.

  10. Variations of upper plate mechanics, seismicity, and arc volcanism along the Middle America Trench

    Science.gov (United States)

    Ruh, J.; Sallares, V.; Ranero, C. R.; van Dinther, Y.

    2015-12-01

    The Middle America Trench (MAT) extends from the Riviera Fracture Zone offshore Mexico down to the Panama Fracture Zone. Along the MAT, the oceanic Cocos plate changes in character from the older, deeper and relatively smooth plate offshore Guatemala-Nicaragua to the ~20 km thick crust of Cocos Ridge off Costa Rica. These changes occur because the northern part of the the Cocos plate has been formed at the East Pacific Rise, while the southern part is formed at the Cocos-Nazca spreading center, which is in turn influenced by the Galapagos Hotspot, originating prominent submarine structures such as the Cocos Ridge. In contrast, the terrane forming the overriding plate in the Pacific convergent margin, which is mainly made by the Caribbean Igneous Province rocks, is relatively homogeneous. Thus, this region is an excellent natural example to study the effect of changes in the incoming plate on the tectonics and deformation of the overriding plate. The Nicaragua lake in the north is a result of upper plate extension related to rollback of the subducting slab, whereas in the south, the Talamanca Cordillera indicates compression of the Caribbean crust probably related with the subduction of the Cocos Ridge. We present numerical models that help to understand the long-term effects of variable subducting oceanic crust age and thickness on upper plate deformation and magmatism. Furthermore, we investigate the seismic behavior of these different convergent systems. The applied numerical model consists of a 2D seismo-thermo-mechanical finite difference scheme with visco-elasto-plastic rheology and a stick-slip frictional formulation to simulate spontaneous nucleation, propagation and arrest of earthquake-like ruptures on physically consistent faults.

  11. Effect of Parametric Uncertainties, Variations, and Tolerances on Thermohydraulic Performance of Flat Plate Solar Air Heater

    Directory of Open Access Journals (Sweden)

    Rajendra Karwa

    2014-01-01

    Full Text Available The paper presents results of an analysis carried out using a mathematical model to find the effect of the uncertainties, variations, and tolerances in design and ambient parameters on the thermohydraulic performance of flat plate solar air heater. Analysis shows that, for the range of flow rates considered, a duct height of 10 mm is preferred from the thermohydraulic consideration. The thermal efficiency changes by about 2.6% on variation in the wind heat transfer coefficient, ±5 K variation in sky temperature affects the efficiency by about ±1.3%, and solar insolation variation from 500 to 1000 Wm−2 affects the efficiency by about −1.5 to 1.3% at the lowest flow rate of 0.01 kgs−1 m−2 of the absorber plate with black paint. In general, these effects reduce with increase in flow rate and are lower for collector with selective coating on the absorber plate surface. The tolerances in the duct height and absorber plate emissivity should be small while positive tolerance of 3° in the collector slope for winter operation and ±3° for year round operation, and a positive tolerance for the gap between the absorber plate and glass cover at nominal value of 40 mm are recommended.

  12. Along-trench variations in the seismic structure of the incoming Pacific plate at the outer rise of the northern Japan Trench

    Science.gov (United States)

    Fujie, Gou; Kodaira, Shuichi; Sato, Takeshi; Takahashi, Tsutomu

    2016-01-01

    To investigate along-trench variations in the seismic structure of the incoming oceanic plate and their effect on water transportation by the oceanic plate, we conducted a wide-angle seismic survey of a trench-parallel transect 270 km long on the outer rise of the northern Japan Trench. The resulting seismic structure models show that the central part of the transect is characterized by rough topography, thick oceanic crust, low seismic velocities, and high Vp/Vs ratios, suggesting pervasive fracturing and high water content (hydration) there. These observations are consistent with the presence of an ancient fracture zone associated with ridge propagation. The trenchward extension of this fracture zone corresponds to an area of low interplate seismicity, low seismic velocities, and high Vp/Vs ratio around the depth of the subduction interface. Our results suggest that this ancient scar on the oceanic plate influences along-trench variations in interplate seismic coupling through its effect on water transportation.

  13. Evaluation of methods to determine the spectral variations of aerosol optical thickness

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.; Talaulikar, M.; Rodrigues, A.; Desa, E.; Chauhan, P.

    The methods used to derive spectral variations of aerosol optical thickness, AOT are evaluated. For our analysis we have used the AOT measured using a hand held sunphotometer at the coastal station on the west coast of India, Dona-Paula, Goa...

  14. Thermal variations of domain wall thickness and number of domains in magnetic rectangular grains

    Science.gov (United States)

    Xu, Song; Merrill, Ronald T.

    1990-12-01

    Equilibrium domain wall thickness and number of domains in rectangular magnetic grains are determined by using a modified Amar model. It is shown that domain structure, particularly domain wall thickness, in a magnetized grain depends strongly on grain shape and orientation. These dependencies are attributed to the existence of two competing self-magnetostatic interactions, one from the ends of the grain and the other from the sides. One of the consequences of this is that the thermal variation of domain wall thickness in an elongated grain is greater (smaller) than predicted by classical theory when the grain is magnetized along the shortest (longest) dimension. For magnetite, classical theory provides a good approximation in predicting both domain wall thickness and number of domains in equal-dimensional grains larger than about 4 μm.

  15. An investigation into the relationship between thickness variations and manufacturing techniques of mouthguards.

    Science.gov (United States)

    Farrington, Timothy; Coward, Trevor; Onambele-Pearson, Gladys; Taylor, Rebecca L; Earl, Philip; Winwood, Keith

    2016-02-01

    The aim of this study was to measure the finished thickness of a single identical 4-mm EVA mouthguard model from a large fabricated sample group and to evaluate the degree of material thinning and variations during the fabrication process. Twenty boxes were distributed to dental technician participants, each containing five duplicated dental models (n = 100), alongside 5 × 4 mm mouthguard blanks and a questionnaire. The mouthguards were measured using electronic callipers (resolution: ±0.01 mm) at three specific points. The five thickest and thinnest mouthguards were examined using a CT scanner to describe the surface typography unique to each mouthguard, highlighting dimensional thinning patterns during the fabrication process. Of the three measurement points, the anterior sulcus point of the mouthguard showed a significant degree of variation (up to 34% coefficient of variation), in finished mouthguard thickness between individuals. The mean thickness of the mouthguards in the anterior region was 1.62 ± 0.38 mm with a range of 0.77-2.80 mm. This variation was also evident in the occlusion and posterior lingual regions but to a lesser extent (up to 12.2% and 9.8% variations, respectively). This study highlights variability in the finished thickness of the mouthguards especially in the anterior sulcus region measurement point, both within and between individuals. At the anterior region measurement point of the mouthguard, the mean thickness was 1.62 mm, equating to an overall material thinning of 59.5% when using a single 4-mm EVA blank. This degree of thinning is comparative to previous single operator research studies. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Variations of the crustal thickness in Nepal Himalayas based on tomographic inversion of regional earthquake data

    Directory of Open Access Journals (Sweden)

    I. Koulakov

    2014-10-01

    Full Text Available We estimate variations of the crustal thickness beneath the Nepal Himalayas based on tomographic inversion of regional earthquake data. We have obtained a low-velocity anomaly in the upper part of the model down to depths of 40 to 80 km and proposed that the lower limit of this anomaly represents variations of the Moho depth. This statement was supported by results of synthetic modeling. The obtained variations of crustal thickness match fairly well with the free-air gravity anomalies: thinner crust patterns correspond to lower gravity values and vice versa. There is also some correlation with magnetic field: higher magnetic values correspond to the major areas of thicker crust. We propose that elevated magnetic values can be associated with more rigid segments of the incoming Indian crust which cause more compression in the thrust zone and leads to stronger crustal thickening.

  17. Variations in debris distribution and thickness on Himalayan debris-covered glaciers

    Science.gov (United States)

    Gibson, Morgan; Rowan, Ann; Irvine-Fynn, Tristram; Quincey, Duncan; Glasser, Neil

    2016-04-01

    Many Himalayan glaciers are characterised by extensive supraglacial debris coverage; in Nepal 33% of glaciers exhibit a continuous layer of debris covering their ablation areas. The presence of such a debris layer modulates a glacier's response to climatic change. However, the impact of this modulation is poorly constrained due to inadequate quantification of the impact of supraglacial debris on glacier surface energy balance. Few data exist to describe spatial and temporal variations in parameters such as debris thickness, albedo and surface roughness in energy balance calculations. Consequently, improved understanding of how debris affects Himalayan glacier ablation requires the assessment of surface energy balance model sensitivity to spatial and temporal variability in these parameters. Measurements of debris thickness, surface temperature, reflectance and roughness were collected across Khumbu Glacier during the pre- and post-monsoon seasons of 2014 and 2015. The extent of the spatial variation in each of these parameters are currently being incorporated into a point-based glacier surface energy balance model (CMB-RES, Collier et al., 2014, The Cryosphere), applied on a pixel-by-pixel basis to the glacier surface, to ascertain the sensitivity of glacier surface energy balance and ablation values to these debris parameters. A time series of debris thickness maps have been produced for Khumbu Glacier over a 15-year period (2000-2015) using Mihalcea et al.'s (2008, Cold Reg. Sci. Technol.) method, which utilised multi-temporal ASTER thermal imagery and our in situ debris surface temperature and thickness measurements. Change detection between these maps allowed the identification of variations in debris thickness that could be compared to discrete measurements, glacier surface velocity and morphology of the debris-covered area. Debris thickness was found to vary spatially between 0.1 and 4 metres within each debris thickness map, and temporally on the order of 1

  18. Computerized Ultrasonic System for On-Line Determination of Chromium Thickness During Plating of Tubes

    Science.gov (United States)

    1993-01-01

    Giordano, Fred Nelson, and John Askew for their cooperation during the shop plating runs; Glen Friar for his encouragement; William Korman for his usual...ATTN: DEPT FOR SCI AND TECH I ATTN: SMCRI-ENM THE PENTAGON ROCK ISLAND, IL 61299-5000 WASHINGTON, D.C. 20310-0103 MIAC/ CINDAS ADMINISTRATOR PURDUE

  19. A new orthogonality relationship for orthotropic thin plate theory and its variational principle

    Institute of Scientific and Technical Information of China (English)

    LUO; Jianhui; LONG; Yuqiu

    2005-01-01

    The thought how dual vectors are constructed in a new orthogonality relationship for theory of elasticity is generalized into orthotropic thin plate bending problems by using the analogy theory between plane elasticity problems and plate bending problems. Dual differential equations are directly obtained by using a mixed variables method. A dual differential matrix to be derived possesses a peculiarity of which principal diagonal sub-matrixes are zero matrixes. Two independently and symmetrically orthogonality sub-relationships are discovered. By using the integral form for elastic bending theory of orthotropic thin plate the orthogonality relationship is demonstrated. By selecting felicitous dual vectors a new orthogonality relationship for theory of elasticity can be generalized into elastic bending theory of orthotropic thin plate. By using the integral form a variational principle which is relative to differential form and a whole function expression are proposed.

  20. Improvement of machining quality of copper-plated roll mold by controlling temperature variation

    Institute of Scientific and Technical Information of China (English)

    Tae-Jin JE; Eun-Chae JEON; Sang-Cheon PARK; Doo-Sun CHOI; Kyung-Hyun WHANG; Myung-Chang KANG

    2011-01-01

    Micro prism film used in LCD industry can be manufactured by roll to roll method with copper-plated roll mold. As copper-plated roll mold is getting larger, pitch error is getting severer. The pitch error drops the quality of micro prism film. The main cause of the pitch error was investigated during machining large roll mold whose machined length was 1 200 mm. The temperature of machining system was elevated during machining roll mold, and this elevation induced thermal expansion of the system. The temperature variation around the roll mold also made thermal expansion of the roll mold. The amount of thermal expansion had strong relationship to the amount of pitch error. Therefore, the roll mold was machined after warming-up of machining system and precise temperature controller around copper-plated roll mold was installed, which minimized the temperature variation. Finally,precise micro prism patterns without pitch error were machined on the large roll mold.

  1. Inter-observer variation in identifying mammals from their tracks at enclosed track plate stations

    Science.gov (United States)

    William J. Zielinski; Fredrick V. Schlexer

    2009-01-01

    Enclosed track plate stations are a common method to detect mammalian carnivores. Studies rely on these data to make inferences about geographic range, population status and detectability. Despite their popularity, there has been no effort to document inter-observer variation in identifying the species that leave their tracks. Four previous field crew leaders...

  2. Compaction Behavior and Part Thickness Variation in Vacuum Infusion Molding Process

    Science.gov (United States)

    Yang, Jinshui; Xiao, Jiayu; Zeng, Jingcheng; Jiang, Dazhi; Peng, Chaoyi

    2012-06-01

    In vacuum infusion molding process (VIMP), it is difficult to manufacture a composite part with small dimensional tolerance, since the upper mold for the process is flexible. In this study, the static and cyclic compaction responses of five kinds of fabrics were experimentally studied under real VIMP conditions, with the effects of compaction pressure, compaction time, compaction cycle and number of the fabric layers. The static and cyclic compaction responses of the all fabrics follow different power law models and the resulting fiber volume fraction and relaxation factor increase with the number of layers. Although the resulting fiber volume fraction increases with the layer numbers, change of the fiber volume fraction of the composite parts with 10 layers to 100 layers of the all fabrics is less than 2.5%. The thickness of the composite part was monitored and measured using micrometer gauges, and the effects of processing parameters on the final thickness of part was investigated. The part thickness varies as a function of spatial coordinates and time during pre-filling, filling and post-filling stages in VIMP. The variation and the final value of the part thickness would be significantly affected by the processing parameters. Statistical results show that the final part thickness is equivalent to the thickness of the dry preform under the 0.08 MPa vacuum compaction pressure in VIMP. The difference between the fiber volume fraction of the final part and that of the dry preform is 2% ~ 5.7%.

  3. Cloud optical thickness variations during 1983-1991: Solar cycle or ENSO?

    Science.gov (United States)

    Kuang, Zhiming; Jiang, Yibo; Yung, Yuk L.

    Based on a detailed analysis of the cloud data obtained by the International Satellite Cloud Climatology Project (ISCCP) in the years 1983-1991, we show that besides the reported 3% variation in global cloudiness (Svensmark and Friis-Christensen, 1997), the global mean cloud optical thickness (MCOT) also has significant variation which is out of phase with that of the global cloudiness. The combined effect of the two opposing variations may be a null effect on the cloud reflectivity. These results are consistent with the Total Ozone Mapping Spectrometer (TOMS) reflectivity measurements. The MCOT variation is further shown to be correlated with both the solar cycle and the ENSO cycle. Our present analysis cannot distinguish which of the above two provides better correlation, although independent data from the High resolution Infrared Radiation Sounder (HIRS) from 1990 to 1996 favor the solar cycle. Future data are needed to identify the true cause of these changes.

  4. UNCONVENTIONAL HAMILTON-TYPE VARIATIONAL PRINCIPLES FOR DYNAMICS OF REISSNER SANDWICH PLATE

    Institute of Scientific and Technical Information of China (English)

    HUANG Wei-jiang; LUO En; SHE Hui

    2006-01-01

    According to the basic idea of classical yin-yang complementarity and modern dual-complementarity, in a simple and unified way proposed by Luo(1987), some unconventional Hamilton-type variational principles for dynamics of Reissner sandwich plate can be established systematically. The unconventional Hamilton-type variation principle can fully characterize the initial-boundary-value problem of this dynamics. In this paper, an important integral relation is given, which can be considered as the generalized principle of virtual work in mechanics. Based on this relation, it is possible not only to obtain the principle of virtual work in dynamics of Reissner sandwich plate, but also to derive systematically the complementary functionals for five-field, two-field and one-field unconventional Hamilton-type variational principles by the generalized Legender transformations. Furthermore, with this approach, the intrinsic relationship among the various principles can be explained clearly.

  5. Effects of variation of environmental parameters on the performance of Resistive Plate Chamber detectors

    Energy Technology Data Exchange (ETDEWEB)

    Meghna, K.K. [INO Graduate Training Programme and Saha Institute of Nuclear Physics, Kolkata 700064 (India); Homi Bhabha National Institute, Mumbai 400085 (India); Biswas, S. [School of Physical Sciences, National Institute of Science Education and Research, Bhubaneswar 751005 (India); Jash, A. [INO Graduate Training Programme and Saha Institute of Nuclear Physics, Kolkata 700064 (India); Homi Bhabha National Institute, Mumbai 400085 (India); Chattopadhyay, S. [Variable Energy Cyclotron Centre, Kolkata 700064 (India); Homi Bhabha National Institute, Mumbai 400085 (India); Saha, S., E-mail: satyajit.saha@saha.ac.in [Applied Nuclear Physics Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India); Homi Bhabha National Institute, Mumbai 400085 (India)

    2016-04-21

    Performance of single gap Resistive Plate Chamber (RPC) detectors is investigated under variation of environmental parameters, such as temperature and relative humidity. Operational characteristics of the RPCs depend on both the environmental temperature and the relative humidity. Sensitivity to such dependence is found to be more on temperature rather than the relative humidity. Qualitative interpretation of some of the results obtained is given based on the known properties of the electrode materials and gases used in the detectors. - Highlights: • Performance of single gap bakelite Resistive Plate Chamber (RPC) detectors is investigated under independent variation of environmental temperature and relative humidity. • Parameters such as leakage currents, noise rates, efficiency and timing characteristics of RPCs are investigated. • Operational characteristics of the RPCs depend on both the environmental temperature and the relative humidity. • Sensitivity of the operational parameters to variation of environmental parameters is found to be more on temperature rather than the relative humidity.

  6. On plane stress state and stress free deformation of thick plate with FGM interface under thermal loading

    Science.gov (United States)

    Szubartowski, Damian; Ganczarski, Artur

    2016-10-01

    This paper demonstrates the plane stress state and the stress free thermo-elastic deformation of FGM thick plate under thermal loading. First, the Sneddon-Lockett theorem on the plane stress state in an isotropic infinite thick plate is generalized for a case of FGM problem in which all thermo-mechanical properties are optional functions of depth co-ordinate. The proof is based on application of the Iljushin thermo-elastic potential to displacement type system of equations that reduces it to the plane stress state problem. Then an existence of the purely thermal deformation is proved in two ways: first, it is shown that the unique solution fulfils conditions of simultaneous constant temperature and linear gradation of thermal expansion coefficient, second, proof is based directly on stress type system of equations which straightforwardly reduces to compatibility equations for purely thermal deformation if only stress field is homogeneous in domain and at boundary. Finally, couple examples of application to an engineering problem are presented.

  7. Physiological variation of segmented OCT retinal layer thicknesses is short-lasting.

    Science.gov (United States)

    Balk, Lisanne; Mayer, Markus; Uitdehaag, Bernard M J; Petzold, Axel

    2013-12-01

    The application of spectral domain optical coherence tomography as a surrogate for neurodegeneration in a range of neurological disorders demands better understanding of the physiological variation of retinal layer thicknesses, which may mask any value of this emerging outcome measure. A prospective study compared retinal layer thicknesses between control subjects (n = 15) and runners (n = 27) participating in a 10-km charity run. Three scans were performed using an eye-tracking function (EBF) and automated scan registration for optimal precision at (1) baseline, (2) directly after the run, and (3) following a rehydration period. Retinal layer segmentation was performed with suppression of axial retinal vessel signal artifacts. Following the run, there was an increase in the relative retinal nerve fibre layer (p = 0.018), the combined inner plexiform/ganglion cell layer (p = 0.038), and the outer nuclear layer (p = 0.018) in runners compared to controls. The initial increase of thickness in the outer nuclear layer of runners (p < 0.0001) was likely related to (noncompliant) rehydration during exercise. Following a period of rest and rehydration, the difference in thickness change for all retinal layers, except the retinal nerve fibre layer (RNFL) (p < 0.05), disappeared between the two groups. There is a quantifiable change in the axial thickness of retinal layersthat which can be explained by an increase in the cellular volume. This effect may potentially be caused by H2O volume shifts.

  8. A Study of the Effect of Gold Thickness Distribution in the Jet Plating Process to Optimize Gold Usage and Plating Voltage Using Design of Experiments

    Directory of Open Access Journals (Sweden)

    Aramphongphun Chuckaphun

    2016-01-01

    Full Text Available A gold plating process in the electronics industry can be classified as (i all surface plating or (ii selective plating. Selective plating is more widely used than all surface plating because it can save more gold used in the plating process and takes less plating time. In this research, the selective plating process called jet plating was studied. Factors that possibly affected the gold usage and plating voltage were also studied to reduce the production cost. These factors included (a plating temperature, (b crystal (inhibitor amount, (c distance between workpiece and anode, (d plating current and (e plating speed. A two-level Full Factorial design with center points was first performed to screen the factors. A Central Composite Design (CCD was then employed to optimize the factors in jet plating. The amount of gold usage should be reduced to 0.366 g / 10,000 pieces, the plating speed should be increased to 4 m/min and the plating voltage should not exceed 8.0 V. According to the analysis, the optimal settings should be as follows: the plating temperature at 55.5 deg C, the crystal amount at 90%, the distance at 0.5 mm, the plating current at 2.8 A, and the plating speed at 4.5 m/min. This optimal setting led to gold usage of 0.350 g / 10,000 pieces and a plating voltage of 7.16 V. Confirmation runs of 30 experiments at the optimal conditions were then performed. It was found that the gold usage and the plating voltage of the confirmation runs were not different from the optimized gold usage and plating voltage. The optimal condition was then applied in production, which could reduce the gold usage by 4.5% and increase the plating speed by 12.5% while the plating voltage did not exceed the limit.

  9. Microstructural evolution of aluminum alloy 7B04 thick plate by various thermal treatments

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-hui; XIONG Bai-qing; ZHANG Yong-an; ZHU Bao-hong; WANG Feng; LIU Hong-wei

    2008-01-01

    The microstructure of an AA 7B04 alloy in the form of plate was investigated using differential scanning calorimetry (DSC) and TEM analysis technologies. Tensile properties and electrical conductivity of AA 7B04 under various heat treatment conditions were also presented. The results reveal that peak-aged microstructure contains GP zones and η' precipitates predominantly. After retrogressing and reaging(RRA), the η' and η precipitates disperse in the alloy matrix, and the η precipitates distribute coarsely and sparsely, decorating the grain boundaries, together with precipitate free zones(PFZs) around them. It is also shown that selecting of suitable heat treatments can provide optimal precipitates in matrix and at grain boundaries, which gives rise to a combination of high strength and stress corrosion cracking(SCC) resistance in such materials.

  10. Comparison of Residual Stress Distributions of Similar and Dissimilar Thick Butt-Weld Plates

    Science.gov (United States)

    Suzuki, Hiroshi; Katsuyama, Jinya; Morii, Yukio

    Residual stress distributions of 35 mm thick dissimilar metal butt-weld between A533B ferritic steel and Type 304 austenitic stainless steel (304SS) with Ni alloy welds and similar metal butt-weld of 304SS were measured using neutron diffraction. Effects of differences in thermal expansion coefficients (CTEs) and material strengths on the weld residual stress distributions were discussed by comparison of the residual stress distributions between the similar and dissimilar metal butt-welds. Residual stresses in the similar metal butt-weld exhibited typical distributions found in a thick butt-weld and they were distributed symmetrically on either side of the weld line. Meanwhile, asymmetric residual stress distributions were observed near the root of the dissimilar metal butt-weld, which was caused by differences in CTEs and yield strengths among both parent materials and weld metals. Transverse residual stress distribution of the dissimilar metal butt-weld was similar trend to that of the similar metal butt-weld, since effect of difference in CTEs were negligible, while magnitude of the transverse residual stress near the root depended on the yield strengths of each metal. In contrast, the normal and longitudinal residual stresses in the dissimilar metal butt-weld distributed asymmetrically on either side of weld line due to influence of differences in CTEs.

  11. Developments in variational methods for high performance plate and shell elements

    Science.gov (United States)

    Felippa, Carlos A.; Militello, Carmelo

    1991-01-01

    High performance elements are simple finite elements constructed to deliver engineering accuracy with coarse arbitrary grids. This is part of a series on the variational foundations of high-performance elements, with emphasis on plate and shell elements constructed with the free formulation (FF) and assumed natural strain (ANS) methods. Parameterized variational principles are studied that provide a common foundation for the FF and ANS methods, as well as for a combination of both. From this unified formulation a variant of the ANS formulation, called the assumed natural deviatoric strain (ANDES) formulation, emerges as an important special case. The first ANDES element, a high-performance 9 degrees of freedom triangular Kirchhoff plate bending element, is briefly described to illustrate the use of the new formulation.

  12. Modelling and optimization of film thickness variation for plasma enhanced chemical vapour deposition processes

    Science.gov (United States)

    Waddell, Ewan; Gibson, Des; Lin, Li; Fu, Xiuhua

    2011-09-01

    This paper describes a method for modelling film thickness variation across the deposition area within plasma enhanced chemical vapour deposition (PECVD) processes. The model enables identification and optimization of film thickness uniformity sensitivities to electrode configuration, temperature, deposition system design and gas flow distribution. PECVD deposition utilizes a co-planar 300mm diameter electrodes with separate RF power matching to each electrode. The system has capability to adjust electrode separation and electrode temperature as parameters to optimize uniformity. Vacuum is achieved using dry pumping with real time control of butterfly valve position for active pressure control. Comparison between theory and experiment is provided for PECVD of diamond-like-carbon (DLC) deposition onto flat and curved substrate geometries. The process utilizes butane reactive feedstock with an argon carrier gas. Radiofrequency plasma is used. Deposited film thickness sensitivities to electrode geometry, plasma power density, pressure and gas flow distribution are demonstrated. Use of modelling to optimise film thickness uniformity is demonstrated. Results show DLC uniformity of 0.30% over a 200 mm flat zone diameter within overall electrode diameter of 300mm. Thickness uniformity of 0.75% is demonstrated over a 200mm diameter for a non-conformal substrate geometry. Use of the modelling method for PECVD using metal-organic chemical vapour deposition (MOCVD) feedstock is demonstrated, specifically for deposition of silica films using metal-organic tetraethoxy-silane. Excellent agreement between experimental and theory is demonstrated for conformal and non-conformal geometries. The model is used to explore scalability of PECVD processes and trade-off against film thickness uniformity. Application to MEMS, optical coatings and thin film photovoltaics is discussed.

  13. Transmission analysis of ultrasonic Lamb mode conversion in a plate with partial-thickness notch.

    Science.gov (United States)

    Xu, Kailiang; Ta, Dean; Su, Zhongqing; Wang, Weiqi

    2014-01-01

    Mode conversions of Lamb waves can occur upon encountering damage or defect such as a notch, leading to newly-converted modes apart from wave reflection and transmission. In this paper, the transmission of the fundamental Lamb modes symmetrical S0 and anti-symmetrical A0 with anti-symmetrical notches were investigated in steel plates within the relatively short propagation distance. The group velocity and modal energy of the converted modes were analyzed using simulations and experiments. Two-dimensional finite difference time domain (2D-FDTD) method was employed to calculate the scattering field and extract numerical trends for simulation study and experimental confirmation. Both simulations and experiments revealed that the apparent group velocities of the converted modes in the transmitted signals subject to the notch positions. To describe the mode conversion degree and evaluate the notch severity, wave packets of the originally-transmitted modes and newly-converted modes were separated and corresponding mode energy percentages were analyzed at different notch severities. Frequency-sweeping measurements illustrated that the modal energy percentages varied monotonically over the notch-depth increase with a statistically consistency (R=1.00, P<0.0004).

  14. Physiological variation of retinal layer thickness is not caused by hydration: a randomised trial.

    Science.gov (United States)

    Balk, Lisanne J; Oberwahrenbrock, Timm; Uitdehaag, Bernard M J; Petzold, Axel

    2014-09-15

    There is evidence for physiological variation of retinal thicknesses as determined by optical coherence tomography (OCT). We tested if such changes could be explained by hydration and would exceed what may be expected from normal ageing. Subjects (n=26) of a previous study were re-assessed and were randomised to 3 groups of a hydration escalation trial (no hydration, 1× hydration, 2× hydration). Automated retinal layer segmentations were performed for the macular retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL) and outer nuclear layer (ONL). The averaged volumes were calculated for the central foveola, 3 mm and 6 mm circles of the ETDRS grid. Following oral hydration there were no significant differences of retinal layer thicknesses between the three randomised groups in any of the ETDRS regions at any time-point. Ageing related changes were significant over an 18 month period for the GCL. The negative outcome of this trial implies that, until the causes for the observed variation are resolved, investigators may need to accept, and include into trial power calculations, a small degree of variation (<1%) of quantitative SD-OCT imaging either due to human physiology or instrument/software related factors.

  15. Gestation length, mode of delivery, and neonatal line-thickness variation.

    Science.gov (United States)

    Zanolli, Clément; Bondioli, Luca; Manni, Franz; Rossi, Paola; Macchiarelli, Roberto

    2011-12-01

    The transition from an intra- to extra-uterine environment leaves its mark in deciduous teeth (and first permanent molars) as an accentuated enamel incremental ring called the neonatal line (NL). This prominent microfeature separates the enamel formed during intrauterine life from that formed after leaving the womb. However, while the physical structure of this scar is well known, the bases of its formation are still a matter of investigation. In particular, besides the influence of the birth-related abrupt environmental and dietary changes and the role played by physiological factors such as hypocalcaemia, a direct relationship between NL thickness variation and the physical was trauma implied by the birth dynamics, the Caesarean, and the operative modes are apparently associated with the thinnest and the thickest lines, respectively. By using the histological record from a deciduous dental sample (exfoliated crowns) of 100 modern healthy school-aged children (47 males and 53 females) of reported birth histories (normal delivery mode: 55 cases; Caesarean: 40; operative: 5), we investigated the relationships between birth dynamics and NL thickness variation. The Tukey Honest Significant Difference method was used to test the differences between the means of the grouping levels. The results of our histo-morphological investigation do not support the suggestion that Caesarean-born children display, on average, a thinner enamel scar compared to children associated to a normal delivery mode. Rather, our study points to the influence exerted by factors intimately related to gestational length variation on the degree of expression of the line.

  16. Micromagnetic simulation of thickness variation of Neel cap in hybrid Bloch-Neel domain wall

    Energy Technology Data Exchange (ETDEWEB)

    Lu Mai [Key Lab. of Opto-Electronic Technology and Intelligent Control, Lanzhou Jiaotong University, Ministry of Education, P.O. Box 73, 118 West Anning Road, Lanzhou 730070, Gansu (China) and Department of Signals and Systems, Chalmers University of Technology, SE-412 96, Gothenburg (Sweden)]. E-mail: m.lu@mail.edu.cn; Leonard, Paul J. [Department of Electronic and Electrical Engineering, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)

    2005-08-01

    The hybrid Bloch-Neel domain wall in iron film has been investigated using three-dimensional micromagnetic calculations. Magnetization distributions in the film plane and cross-section are presented. In the film plane the rotation of magnetization in the 180 deg domain wall takes two different patterns from the bottom layer to the top layer. In cross-section the C-shaped magnetization distribution with hybrid Bloch-Neel domain wall has been found. The thickness of the top Neel cap changes from its largest value as the C-shaped magnetization distribution appears, and becomes thinner as the C-shaped magnetization distribution gradually moves and grows up. The thickness variation of the bottom Neel cap changes in a similar way, but with a reversal pattern. The results in this paper will enrich our knowledge of magnetic domain and domain wall patterns in magnetic materials.

  17. Variations in bark thickness and sapwood density of Calophyilum inophyllum provenances in Australia and in Sri Lanka

    Institute of Scientific and Technical Information of China (English)

    Subhash Hathurusingha; Nanjappa Ashwath

    2011-01-01

    Sapwood density and bark thickness of Calophyllum inophyl- lum L. (a multipurpose durable timber species) were studied in various locations in Northern Australia and in Sri Lanka. Measurements were taken non-destructively by using core sampling and bark gauge. From each provenance, 4-15 mature trees having girth at breast height over bark (GBHOB) at 100-150 cm were selected on the basis of the popula- tion size. Significant (p<0.05) hemispheric and provenance variations in bark thickness were found. Variations in the bark thickness are influ- enced by environmental variables. Variations in sapwood density were less pronounced compared to that of bark thickness. Variations in sap- wood density are likely to be governed by genotypic variations.

  18. Vacuum Die Casting Process and Simulation for Manufacturing 0.8 mm-Thick Aluminum Plate with Four Maze Shapes

    Directory of Open Access Journals (Sweden)

    Chul Kyu Jin

    2015-02-01

    Full Text Available Using vacuum die casting, 0.8 mm-thick plates in complicated shapes are manufactured with the highly castable aluminum alloy Silafont-36 (AlSi9MgMn. The sizes and shapes of the cavities, made of thin plates, feature four different mazes. To investigate formability and mechanical properties by shot condition, a total of six parameters (melt temperatures of 730 °C and 710 °C; plunger speeds of 3.0 m/s and 2.5 m/s; vacuum pressure of 250 mbar and no vacuum are varied in experiments, and corresponding simulations are performed. Simulation results obtained through MAGMA software show similar tendencies to those of the experiments. When the melt pouring temperature is set to 730 °C rather than 710 °C, formability and mechanical properties are superior, and when the plunger speed is set to 3.0 m/s rather than to 2.5 m/s, a fine, even structure is obtained with better mechanical properties. The non-vacuumed sample is half unfilled. The tensile strength and elongation of the sample fabricated under a melt temperature of 730 °C, plunger speed of 3.0 m/s, and vacuum pressure of 250 mbar are 265 MPa and 8.5%, respectively.

  19. VARIATIONS IN CRUSTAL THICKNESS OF THE KANE TRANSFORM IN THE NORTH ATLANTIC OCEAN

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new approach was taken to investigate the crustal stucture of the Kane transform and its aseismic extension, using high quality bathymetry and gravity data. The gravity signatures associated with variations in crustal thickness of the transform were isolated from the observed free-air anomaly,was continued downward to the mean depth of the crust/mantle interface and converted onto the relief on that surface. The crustal thickness of the transform was then calculated by subtracting seawater depth from the depth of the gravity-inferred crust/mantle interface. 3-D gravity investigation results indicate that the Kane transform and adjacent areas are associated with a crust thinner than normal oceanic crust. The transform trough is largely underlain by a crust less than 4.5km thick and in the nodal basins the crust may be as thin as 3 km. The crust beneath the fracture zone valley is 4 - 5.5 km thick. The rift valleys on the spreading segments are also characterized by thin crust (4 - 5 km thick). Thin oceanic crust extends to 20 - 30 km from the transform axis, except for some localized places such as the inside comer highs adjoining the ridge-transform intersections. These gravity-inferred results match fairly well with limited published seismic results. Thinning of the crust is mainly attributable to a thin layer 3, which in tum may be explained by the combined effects of reduced magma supply at the ends of the spreading segments and tectonic activities in the region.

  20. VARIATIONS IN CRUSTAL THICKNESS OF THE KANE TRANSFORM IN THE NORTH ATLANTIC OCEAN

    Institute of Scientific and Technical Information of China (English)

    PhilipD.Rabinowitz; 胡延昌

    2001-01-01

    A new approach was taken to investigate the crustal stucture of the Kane transform and its aseismic extension, using high quality bathymetry and gravity data. The gravity signatures associated with variations in crustal thickness of the transform were isolated from the observed free-air anomaly,was continued downward to the mean depth of the crust/mantle interface and converted on to the relief onthat surface. The crustal thickness of the transform was then calculated by subtracting seawater depth from the depth of the gravity-inferred crust/mantle interface. 3-D gravity investigation results indicate that the Kane transform and adjacent areas are associated with a crust thinner than normal oceanic crust. The transform trough is largely underlain by a crust less than 4.5kin thick and in the nodal basins the crust may be as thin as 3 kin. The crust beneath the fracture zone valley is 4 - 5.5 km thick. The rift valleys on the spreading segments are also characterized by thin crust (4 - 5 km thick). Thin oceanic crust extends to 20-30 km from the transform axis,except for some localized places such as the inside comerhighs adjoining the ridge-transform intersections. These gravity-inferred results match fairly well with limited published seismic results. Thinning of the crust is mainly attributable to a thin layer 3, which in turn may be explained by the combined effects of reduced magma supply at the ends of the spreading segments and tectonic activities in the region.

  1. Effect of Plate Thickness on Tensile Property of Ti-6Al-4V Alloy Joint Friction Stir Welded Below β-Transus Temperature

    Science.gov (United States)

    Ji, Shude; Wang, Yue; Li, Zhengwei; Ma, Lin; Zhang, Liguo; Yue, Yumei

    2017-07-01

    Defect-free joint of Ti-6Al-4V alloy was successfully friction stir welded below β-transus temperature and then tensile tests were performed. Microstructure, macrostructure, tensile properties and fracture position are mainly discussed in order to investigate how surface indentation and plate thickness influence the tensile property. Weld zone (WZ) attained below β-transus temperature that owns better tensile strength limit than base metal (BM). During the tensile test, the elongation is decided by whether BM yields. Compared with friction stir welding joint using 2.5 mm thick plate, it is very difficult for joint using 2 mm thick plates to get bigger elongation due to surface indentation. Due to the higher tensile property of the WZ, the joint without surface indentation fractures at BM, reaching the 58.46 % elongation of BM.

  2. Casimir force between a half-space and a plate of finite thickness

    Science.gov (United States)

    Høye, Johan S.; Brevik, Iver

    2016-05-01

    Zero-frequency Casimir theory is analyzed from different viewpoints, with the aim of obtaining further insight into the delicate Drude-plasma issue that turns up when one considers thermal corrections to the Casimir force. The problem is essentially that the plasma model, physically inferior in comparison to the Drude model since it leaves out dissipation in the material, apparently gives the best results when comparing with recent experiments. Our geometric setup is quite conventional, namely, a dielectric plate separated from a dielectric half-space by a vacuum gap, both media being made of the same material. Our investigation is divided into the following categories: (1) Making use of the statistical-mechanical method developed by J. S. Høye and I. Brevik [Physica A (Amsterdam, Neth.) 259, 165 (1998), 10.1016/S0378-4371(98)00249-0], implying that the quantized electromagnetic field is replaced by interaction between dipole moments oscillating in harmonic potentials, we first verify that the Casimir force is in agreement with the Drude prediction. No use of Fresnel's reflection coefficients is made at this stage. (2) Then turning to the field-theoretic description implying use of the reflection coefficients, we derive results in agreement with the forgoing when first setting the frequency equal to zero, before letting the permittivity become large. With the plasma relation the reflection coefficient for TE zero-frequency modes depends on the component of the wave vector parallel to the surfaces and lies between 0 and 1. This contradicts basic electrostatic theory. (3) Turning to high-permeability magnetic materials, the TE zero-frequency mode describes the static magnetic field in the same way the TM zero-frequency modes describe the static electric fields in electrostatics. With the plasma model magnetic fields, except for a small part, cannot pass through metals; that is, metals effectively become superconductors. However, recent experimental results clearly

  3. Variation in the thickness of the composite lute with an indirect composite inlay system.

    Science.gov (United States)

    Ariyaratnam, M; Wilson, M A; Wilson, N H; Watts, D C

    1990-11-01

    The findings of an initial investigation of variations in the thickness of the composite lute around inlays of a fine particle hybrid, light- and secondary-cured indirect composite resin inlay system are reported. The lute thickness varied between 10 microns and 90 microns, and was found to be thinnest and most uniform in the region of occlusal cavosurface margins. Although the marginal adaptation of the inlays investigated was generally considered to be satisfactory, sections of the lute were found to exhibit porosity and to contain a number of voids. It is concluded that whilst the lute thickness and marginal adaptation of composite bonded inlays of the type investigated may be found to be acceptable, further work is desirable to investigate ways to limit porosity and voids in lutes and to form and finish the cavomarginal elements of tooth-coloured inlays in such a way that the limiting layer of luting material may be better protected from the rigors of function in the oral environment.

  4. Effects of Velocity-Slip and Viscosity Variation in Squeeze Film Lubrication of Two Circular Plates

    Directory of Open Access Journals (Sweden)

    R.R. Rao

    2013-03-01

    Full Text Available A generalized form of Reynolds equation for two symmetrical surfaces is taken by considering velocity-slip at the bearing surfaces. This equation is applied to study the effects of velocity-slip and viscosity variation for the lubrication of squeeze films between two circular plates. Expressions for the load capacity and squeezing time obtained are also studied theoretically for various parameters. The load capacity and squeezing time decreases due to slip. They increase due to the presence of high viscous layer near the surface and decrease due to low viscous layer.

  5. Variational principles and optimal solutions of the inverse problems of creep bending of plates

    Science.gov (United States)

    Bormotin, K. S.; Oleinikov, A. I.

    2012-09-01

    It is shown that inverse problems of steady-state creep bending of plates in both the geometrically linear and nonlinear formulations can be represented in a variational formulation. Steady-state values of the obtained functionals corresponding to the solutions of the problems of inelastic deformation and elastic unloading are determined by applying a finite element procedure to the functionals. Optimal laws of creep deformation are formulated using the criterion of minimizing damage in the functionals of the inverse problems. The formulated problems are reduced to the problems solved by the finite element method using MSC.Marc software.

  6. Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines

    Directory of Open Access Journals (Sweden)

    Jeffrey Tuck

    2013-12-01

    Full Text Available Analysis of transient fluid pressure signals has been investigated as an alternative method of fault detection in pipeline systems and has shown promise in both laboratory and field trials. The advantage of the method is that it can potentially provide a fast and cost effective means of locating faults such as leaks, blockages and pipeline wall degradation within a pipeline while the system remains fully operational. The only requirement is that high speed pressure sensors are placed in contact with the fluid. Further development of the method requires detailed numerical models and enhanced understanding of transient flow within a pipeline where variations in pipeline condition and geometry occur. One such variation commonly encountered is the degradation or thinning of pipe walls, which can increase the susceptible of a pipeline to leak development. This paper aims to improve transient-based fault detection methods by investigating how changes in pipe wall thickness will affect the transient behaviour of a system; this is done through the analysis of laboratory experiments. The laboratory experiments are carried out on a stainless steel pipeline of constant outside diameter, into which a pipe section of variable wall thickness is inserted. In order to detect the location and severity of these changes in wall conditions within the laboratory system an inverse transient analysis procedure is employed which considers independent variations in wavespeed and diameter. Inverse transient analyses are carried out using a genetic algorithm optimisation routine to match the response from a one-dimensional method of characteristics transient model to the experimental time domain pressure responses. The accuracy of the detection technique is evaluated and benefits associated with various simplifying assumptions and simulation run times are investigated. It is found that for the case investigated, changes in the wavespeed and nominal diameter of the

  7. Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines

    Science.gov (United States)

    Tuck, Jeffrey; Lee, Pedro

    2013-01-01

    Analysis of transient fluid pressure signals has been investigated as an alternative method of fault detection in pipeline systems and has shown promise in both laboratory and field trials. The advantage of the method is that it can potentially provide a fast and cost effective means of locating faults such as leaks, blockages and pipeline wall degradation within a pipeline while the system remains fully operational. The only requirement is that high speed pressure sensors are placed in contact with the fluid. Further development of the method requires detailed numerical models and enhanced understanding of transient flow within a pipeline where variations in pipeline condition and geometry occur. One such variation commonly encountered is the degradation or thinning of pipe walls, which can increase the susceptible of a pipeline to leak development. This paper aims to improve transient-based fault detection methods by investigating how changes in pipe wall thickness will affect the transient behaviour of a system; this is done through the analysis of laboratory experiments. The laboratory experiments are carried out on a stainless steel pipeline of constant outside diameter, into which a pipe section of variable wall thickness is inserted. In order to detect the location and severity of these changes in wall conditions within the laboratory system an inverse transient analysis procedure is employed which considers independent variations in wavespeed and diameter. Inverse transient analyses are carried out using a genetic algorithm optimisation routine to match the response from a one-dimensional method of characteristics transient model to the experimental time domain pressure responses. The accuracy of the detection technique is evaluated and benefits associated with various simplifying assumptions and simulation run times are investigated. It is found that for the case investigated, changes in the wavespeed and nominal diameter of the pipeline are both important

  8. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    ’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through......Copenhagen Business School (CBS) finds itself needing to address the issue of English-medium instruction for its increasing number of foreign exchange and full degree students. With internationalisation as a main pillar of the institution’s agenda, there are concerns whether the teaching faculty...... the Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature...

  9. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    Copenhagen Business School (CBS) finds itself needing to address the issue of English-medium instruction for its increasing number of foreign exchange and full degree students. With internationalisation as a main pillar of the institution’s agenda, there are concerns whether the teaching faculty......’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through...... the Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature...

  10. UNIFORMLY VALID ASYMPTOTIC SOLUTIONS OF THE NONLINEAR UNSYMMETRICAL BENDING FOR ORTHOTROPIC RECTANGULAR THIN PLATE OF FOUR CLAMPED EDGES WITH VARIABLE THICKNESS

    Institute of Scientific and Technical Information of China (English)

    黄家寅

    2004-01-01

    By using "the method of modified two-variable ", "the method of mixing perturbation" and introducing four small parameters, the problem of the nonlinear unsymmetrical bending for orthotropic rectangular thin plate with linear variable thickness is studied. And the uniformly valid asymptotic solution of Nth- order for ε 1 and Mth- order for ε 2of the deflection functions and stress function are obtained.

  11. Low resistivity Ga-doped ZnO thin films of less than 100 nm thickness prepared by ion plating with direct current arc discharge

    OpenAIRE

    2007-01-01

    Low resistivity Ga-doped ZnO films were prepared on a glass substrate by ion plating with direct current arc discharge. Thickness dependent changes in the electrical properties of the films are reported, focusing on the thin films of less than 100 nm thickness. Structural analyses showed that the thinnest film of 30 nm thickness consists of well-oriented columnar grains normal to the substrate, and the resistivity was as low as 4.4×10−4 Ω cm. The changes in lattice strain and c-axis fluctuati...

  12. A variational energy approach for electromechanical analysis of thick piezoelectric beam

    Institute of Scientific and Technical Information of China (English)

    LAU C.W.H.; LIM C.W; LEUNG A.Y.T.

    2005-01-01

    A new two dimensional coupled electromechanical model for athick, laminated beam with piezoelectric and isotropic lamina subjected to static external electric loading is developed. The model combined the first order shear deformation theory for the relatively thick elastic core and linear piezoelectric theory for the piezoelectric lamina. The actuation response is induced through the application of extemal electric voltage. Rayleigh-Ritz method is adopted to model the displacement and potential fields of the beam and governing equations were finally derived from the variational energy principle. The model allows the piezoelectric lamina to be formulated via a two-dimensional model because of the strong electro-mechanical coupling and the presence of a two-dimensional electric field. Numerical examples of piezoelectric laminated beam are presented. It is shown in this paper that a one-dimensional model for the piezoelectric beam-like layer is inadequate.

  13. Analyzing Improving Laser Cutting Accuracy of Moderate Thickness Plate%提高中厚板的激光切割精度分析

    Institute of Scientific and Technical Information of China (English)

    帅军

    2014-01-01

    The paper was analyzed quality defect of plate of moderate thickness. Through adjusting Baichao laser cutting ma-chine parameters and using a series of means prevent overheating in order to improve the precision of laser cutting of medi-um plate, which successfully solved the problem of thick plate cutting quality.%针对中厚板切割质量缺陷进行分析,通过调整百超激光切割机参数,并使用一系列防止过热手段,从而提高中厚板的激光切割精度,成功解决了困扰中厚板切割质量的问题。

  14. Firn thickness variations across the Northeast Greenland Ice Stream margins indicating nonlinear densification rates

    Science.gov (United States)

    Riverman, K. L.; Anandakrishnan, S.; Alley, R. B.; Peters, L. E.; Christianson, K. A.; Muto, A.

    2013-12-01

    Northeast Greenland Ice Stream (NEGIS) is the largest ice stream in Greenland, draining approximately 8.4% of the ice sheet's area. The flow pattern and stability mechanism of this ice stream are unique to others in Greenland and Antarctica, and merit further study to ascertain the sensitivity of this ice stream to future climate change. Geophysical methods are valuable tools for this application, but their results are sensitive to the structure of the firn and any spatial variations in firn properties across a given study region. Here we present firn data from a 40-km-long seismic profile across the upper reaches of NEGIS, collected in the summer of 2012 as part of an integrated ground-based geophysical survey. We find considerable variations in firn thickness that are coincident with the ice stream shear margins, where a thinner firn layer is present within the margins, and a thicker, more uniform firn layer is present elsewhere in our study region. Higher accumulation rates in the marginal surface troughs due to drift-snow trapping can account for some of this increased densification; however, our seismic results also highlight enhanced anisotropy within the firn and upper ice column that is confined to narrow bands within the shear margins. We thus interpret these large firn thickness variations and abrupt changes in anisotropy as indicators of firn densification dependent on the effective stress state as well as the overburden pressure, suggesting that the strain rate increases nonlinearly with stress across the shear margins. A GPS strain grid maintained for three weeks across both margins observed strong side shearing, with rapid stretching and then compression along particle paths, indicating large deviatoric stresses in the margins. This work demonstrates the importance of developing a high-resolution firn densification model when conducting geophysical field work in regions possessing a complex ice flow history; it also motivates the need for a more

  15. Choroidal thickness variation in highly myopic eyes during the water drinking test

    Directory of Open Access Journals (Sweden)

    Renato Antunes Schiave Germano

    Full Text Available ABSTRACT Purpose: To evaluate variations in choroidal thickness (CT during the water drinking test (WDT in emmetropic eyes (EE and highly myopic eyes (ME using spectral-domain optical coherence tomography (SD-OCT. Methods: Clinical trial performed at a tertiary care hospital comprising 30 randomly selected eyes. The WDT and SD-OCT macular scans were performed 10 and 45 min after water ingestion in 15 myopic and 15 EE of 15 healthy patients in each group. Primary study outcomes were average macular CT measured by SD-OCT and intraocular pressure (IOP during the WDT. Results: The mean spherical equivalent refraction was 0.15 ± 0.24 D in emmetropic and -7.1 ± 1.75 D in ME (p<0.001. No statistical differences between EE and ME were observed during the WDT response. EE had higher CT compared with ME at the fovea (361.4 ± 55.4 vs 257.9 ± 95.3; p<0.001, 3 mm nasal to the fovea (158.0 ± 71.8 vs 122.5 ± 54.5; p =0.047, and 3 mm temporally to the fovea (310.6 ± 52.4 vs 247.6 ± 90.1; p=0.05. Regarding CT variation, significant differences in foveal CT at 10 min after water ingestion were observed in both EE and ME, with no statistically significant difference observed between groups. A moderate correlation between IOP peak during the WDT and CT was demonstrated in ME (r=0.52; p=0.04. Conclusions: No statistically significant differences in CT variation during the WDT were observed between EE and ME, indicating similar behavior of the choroidal bed during the WDT in both groups. Further, CT was thinner in highly ME, with CT variation unable to explain elevations in IOP observed during the WDT.

  16. A study of narrow gap laser welding for thick plates using the multi-layer and multi-pass method

    Science.gov (United States)

    Li, Ruoyang; Wang, Tianjiao; Wang, Chunming; Yan, Fei; Shao, Xinyu; Hu, Xiyuan; Li, Jianmin

    2014-12-01

    This paper details a new method that combines laser autogenous welding, laser wire filling welding and hybrid laser-GMAW welding to weld 30 mm thick plate using a multi-layer, multi-pass process. A “Y” shaped groove was used to create the joint. Research was also performed to optimize the groove size and the processing parameters. Laser autogenous welding is first used to create the backing weld. The lower, narrowest part of the groove is then welded using laser wire filling welding. Finally, the upper part of the groove is welded using laser-GMAW hybrid welding. Additionally, the wire feeding and droplet transfer behaviors are observed by high speed photography. The two main conclusions from this work are: the wire is often biased towards the side walls, resulting in a lack of fusion at the joint and the creation of other defects for larger groove sizes. Additionally, this results in the droplet transfer behavior becoming unstable, leading to a poor weld appearance for smaller groove sizes.

  17. A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate

    Directory of Open Access Journals (Sweden)

    Mario E. Gimenez

    2009-01-01

    Full Text Available A gravimetric study was carried out in a region of the Central Andean Range between 28∘ and 32∘ south latitudes and from 72∘ and 66∘ west longitudes. The seismological and gravimetrical Moho models were compared in a sector which coincides with the seismological stations of the CHARGE project. The comparison reveals discrepancies between the gravity Moho depths and those obtained from seismological investigations (CHARGE project, the latter giving deeper values than those resulting from the gravimetric inversion. These discrepancies are attenuated when the positive gravimetric effect of the Nazca plate is considered. Nonetheless, a small residuum of about 5 km remains beneath the Cuyania terrane region, to the east of the main Andean chain. This residuum could be gravimetrically justified if the existence of a high density or eclogitized portion of the lower crust is considered. This result differed from the interpretations from Project “CHARGE” which revealed that the entire inferior crust extending from the Precordillera to the occidental “Sierras Pampeanas” could be “eclogitized”. In this same sector, we calculated the effective elastic thickness (Te of the crust. These results indicated an anomalous value of Te = 30 km below the Cuyania terrane. This is further conclusive evidence of the fact that the Cuyania terrane is allochthonous, for which also geological evidences exist.

  18. Variation in Campylobacter Mulilocus Sequence Typing Subtypes Detected on Three Different Plating Media

    Science.gov (United States)

    Introduction: There are multiple selective plating media available for detection and enumeration of naturally occurring Campylobacter. Campylobacter produce colonies with differing morphology and characteristics depending on the plating medium used. It is unclear if choice of plating medium can a...

  19. Comparison of earthquake source parameters and interseismic plate coupling variations in global subduction zones (Invited)

    Science.gov (United States)

    Bilek, S. L.; Moyer, P. A.; Stankova-Pursley, J.

    2010-12-01

    Geodetically determined interseismic coupling variations have been found in subduction zones worldwide. These coupling variations have been linked to heterogeneities in interplate fault frictional conditions. These connections to fault friction imply that observed coupling variations are also important in influencing details in earthquake rupture behavior. Because of the wealth of newly available geodetic models along many subduction zones, it is now possible to examine detailed variations in coupling and compare to seismicity characteristics. Here we use a large catalog of earthquake source time functions and slip models for moderate to large magnitude earthquakes to explore these connections, comparing earthquake source parameters with available models of geodetic coupling along segments of the Japan, Kurile, Kamchatka, Peru, Chile, and Alaska subduction zones. In addition, we use published geodetic results along the Costa Rica margin to compare with source parameters of small magnitude earthquakes recorded with an onshore-offshore network of seismometers. For the moderate to large magnitude earthquakes, preliminary results suggest a complex relationship between earthquake parameters and estimates of strongly and weakly coupled segments of the plate interface. For example, along the Kamchatka subduction zone, these earthquakes occur primarily along the transition between strong and weak coupling, with significant heterogeneity in the pattern of moment scaled duration with respect to the coupling estimates. The longest scaled duration event in this catalog occurred in a region of strong coupling. Earthquakes along the transition between strong and weakly coupled exhibited the most complexity in the source time functions. Use of small magnitude (0.5 Osa Peninsula relative to the Nicoya Peninsula, mimicking the along-strike variations in calculated interplate coupling.

  20. Age, Sex, and Ethnic Variations in Inner and Outer Retinal and Choroidal Thickness on Spectral-Domain Optical Coherence Tomography.

    Science.gov (United States)

    Bafiq, Rinoza; Mathew, Raeba; Pearce, Elizabeth; Abdel-Hey, Ahmed; Richardson, Matthew; Bailey, Thomas; Sivaprasad, Sobha

    2015-11-01

    To evaluate age, sex, and ethnic variations in inner and outer retinal and choroidal thickness and foveal pit, using spectral-domain optical coherence tomography (SD OCT). Single-center observational cross-sectional study. Ninety randomly selected, healthy individuals of white, black, and South Asian origin underwent SD OCT raster and enhanced depth imaging scan. Manual measurements of inner and outer retinal thickness and choroidal thickness up to 3 mm nasal and temporal to the fovea were performed. The age, sex, and ethnic differences in these parameters were analyzed. The mean inner retinal thickness was lower by approximately 12 μm in black subjects across the central retina compared to white subjects (P thickness below the foveal pit was lower in eyes of blacks compared to South Asians (12 μm, P = .035) and white subjects (18 μm, P thickness decreased by 0.5 μm per year of age of subjects and was thinner by 6.1 μm (P choroidal thickness did not vary between ethnic groups but the temporal choroid was significantly thinner in black subjects (P choroid showed an age-related decline in thickness of 2 μm per year of age of the subjects. Interethnic differences include wider fovea, lower central foveal thickness, and thinner inner retina in eyes of black subjects compared to their white and South Asian counterparts. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Variation of structure and magnetic properties with thickness of thin Co59Fe26Ni15 films

    OpenAIRE

    Chechenin, NG; van Voorthuysen, EHD; De Hosson, JTM; Boerma, DO

    2005-01-01

    Variations of phase composition and magnetic properties of electrodeposited nanocrystalline Co-Fe-Ni films with film thickness in the range of 50-500 nm were analyzed. The samples were magnetically soft with coercivity in the range H-c = 2-20 Oe and uni axial magnetic anisotropy up to H-k = 20 Oe. It was found that H-c decreases and H-k increases with increasing film thickness. The BCC phase dominates at small film thickness up to about 80 nm and the FCC phase increases when the film growths ...

  2. Eggshell thickness variation in red-legged partridge (Alectoris rufa) from Spain

    DEFF Research Database (Denmark)

    Castilla, Aurora M.; de Aragón, Juan Martínez; Herrel, Anthony

    2009-01-01

    Eggshell thickness is commonly used as an indicator of habitat quality and effects of environmental pollution on avian reproduction. We present the first data available on eggshell thickness for Red-legged Partridge (Alectoris rufa) in Spain. We compared eggshell thickness between eggs collected ...

  3. Refinement of Out of Circularity and Thickness Measurements of a Cylinder for Finite Element Analysis

    Science.gov (United States)

    2016-09-01

    deviations from a perfectly round shape and plate thickness variations of a cylinder that is subjected to external pressure are known to have a...thickness variations of a cylinder that is subjected to external pressure are known to have a significant effect on the collapse strength. Non-linear...and plate thickness variations of a cylinder subjected to external pressure are known to have a significant effect on the collapse strength. When

  4. The properties of thickness-twist (TT) wave modes in a rotated Y-cut quartz plate with a functionally graded material top layer.

    Science.gov (United States)

    Wang, Bin; Qian, Zhenghua; Li, Nian; Sarraf, Hamid

    2016-01-01

    We propose the use of thickness-twist (TT) wave modes of an AT-cut quartz crystal plate resonator for measurement of material parameters, such as stiffness, density and material gradient, of a functionally graded material (FGM) layer on its surface, whose material property varies exponentially in thickness direction. A theoretical analysis of dispersion relations for TT waves is presented using Mindlin's plate theory, with displacement mode shapes plotted, and the existence of face-shear (FS) wave modes discussed. Through numerical examples, the effects of material parameters (stiffness, density and material gradient) on dispersion curves, cutoff frequencies and mode shapes are thoroughly examined, which can act as a theoretical reference for measurements of unknown properties of FGM layer.

  5. Dependence Of The Structure And Magnetic Properties Of Cast Plate-Shaped Nd60Fe30Al10 Samples On Their Thickness

    Directory of Open Access Journals (Sweden)

    Michalski B.

    2015-09-01

    Full Text Available The hard magnetic Nd-Fe-Al alloys are inferior to Nd-Fe-B magnets as far as the magnetic properties are concerned, but their great advantage is that they need no additional annealing to achieve good magnetic properties. These properties depend on the cooling rate from the melting state, and on the thickness of the sample - the best values are achieved at the quenching rates at which the samples have a thickness of 0.3-2 mm. The present study is concerned with the correlation between the magnetic properties of the plate-shaped Nd60Fe30Al10 samples and their size - thickness. Two casting ways: with the melt stream perpendicular direction and parallel to the surface of the plates were used. The plates were produced by pressure casting and suction casting. The studies have shown that the cooling rates depends on local propagation on liquid metal in the mold resulting in heterogeneity of structure and properties.

  6. Variation of structure and magnetic properties with thickness of thin Co59Fe26Ni15 films

    NARCIS (Netherlands)

    Chechenin, NG; van Voorthuysen, EHD; De Hosson, JTM; Boerma, DO

    2005-01-01

    Variations of phase composition and magnetic properties of electrodeposited nanocrystalline Co-Fe-Ni films with film thickness in the range of 50-500 nm were analyzed. The samples were magnetically soft with coercivity in the range H-c = 2-20 Oe and uni axial magnetic anisotropy up to H-k = 20 Oe. I

  7. The use of STEM imaging to analyze thickness variations due to electromigration-induced mass transport in thin polycrystalline nanobridges

    NARCIS (Netherlands)

    Rudneva, M.; Kozlova, T.; Zandbergen, H.W.

    2014-01-01

    Scanning transmission electron microscopy (STEM) imaging is applied to analyze the electromigration-induced thickness variations of thin polycrystalline films, It is shown that a high angle annular dark field (HAADF) detector is required to minimize the effect of diffraction contact. A further reduc

  8. Variations of the soft tissue thicknesses external to the ribs in pectus excavatum patients.

    Science.gov (United States)

    Rodrigues, Pedro L; Direito-Santos, Bruno; Moreira, António H J; Fonseca, Jaime C; Pinho, A C M; Rodrigues, Nuno F; Henriques-Coelho, Tiago; Correia-Pinto, Jorge; Vilaça, João L

    2013-09-01

    Surgical repair of pectus excavatum (PE) has become more popular due to improvements in the minimally invasive Nuss procedure. The pre-surgical assessment of PE patients requires Computerized Tomography (CT), as the malformation characteristics vary from patient to patient. This work aims to characterize soft tissue thickness (STT) external to the ribs among PE patients. It also presents a comparative analysis between the anterior chest wall surface before and after surgical correction. Through surrounding tissue segmentation in CT data, STT values were calculated at different lines along the thoracic wall, with a reference point in the intersection of coronal and median planes. The comparative analysis between the two 3D anterior chest surfaces sets a surgical correction influence area (SCIA) and a volume of interest (VOI) based on image processing algorithms, 3D surface algorithms, and registration methods. There are always variations between left and right side STTs (2.54 ± 2.05 mm and 2.95 ± 2.97 mm for female and male patients, respectively). STTs are dependent on age, sex, and body mass index of each patient. On female patients, breast tissue induces additional errors in bar manual conception. The distances starting at the deformity's largest depression point at the SCIA are similar in all directions. Some diverging measures and outliers were found, being difficult to find similar characteristics between them, especially in asymmetric patients. The Nuss procedure metal bar must be modeled according to each patient's special characteristics. The studied relationships between STT and chest surface could represent a step forward to eliminate the CT scan from PE pre-surgical evaluation. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Coefficient of Variation Estimates for the Plate Boundary Fault System of California

    Science.gov (United States)

    Biasi, G. P.; Scharer, K. M.

    2015-12-01

    The number of high-quality paleoseismic records on major strike-slip faults of California has increased in recent years to the point that patterns in earthquake recurrence are emerging. The degree of predictability in time intervals between ground-rupturing earthquakes can be measured by the CoV (coefficient of variation). The CoV approximately normalizes for mean recurrence, and is thus useful to isolate the temporal variability of earthquake records. CoV estimates are themselves uncertain because input dates are actually probability distributions and because paleoseismic records are short and not necessarily representative samples from the underlying recurrence distribution. Radiocarbon dating uncertainty can be incorporated by sampling from event PDFs and compiling sample CoV estimates. Uncertainty due to the brevity of the site event record is larger, and neglect of it can lead to improbable estimates. Long records are now available on the San Andreas and San Jacinto faults in Southern California, and the San Andreas and Hayward faults in northern California. These faults accommodate most of the Pacific-North American relative plate motion in their respective regions. CoV estimates from sites with 8 or more events cluster around 0.63, but are as low as 0.4 for the southern Hayward fault. Sites with fewer events give similar estimates, though with lower resolution. The one prominent outlier, Burro Flats, with a CoV near 1.0, is in a region of severe fault complexity and rapid fault-normal compression. Quasi-periodic recurrence is emerging as a general property for these plate boundary faults. Some individual site records allow that, at low probabilities, recurrence could be random in time. When the ensemble is considered together, however, it is improbable that we would see the observed degree of agreement among boundary fault paleoseismic records; the more likely explanation is that quasi-periodic recurrence is a real property of the boundary fault system.

  10. Study on the Thickness Change of Nickel-Plated Layer in Fabrication of the Silver Hollow Nickel Waveguides by the Outer-Coating Method of the Liquid Phase Process

    CERN Document Server

    Ro, Sok-Bong; Kim, Uo-Hyon

    2016-01-01

    A metallic hollow waveguide is promising fiber for the delivery of laser radiation. Thickness of the nickel plated layer for supporting of the waveguide in fabrication of a dielectric coated silver hollow nickel waveguide is very important factor. In this paper, the change characteristic in the thickness of the nickel plated layer along the length of the silver coated glass mandrel during fabricating the silver hollow nickel waveguide by the outer-coating method of the liquid phase process has been studied both experimentally and analytically. Waveguides with uniform thickness of the nickel plated layer along the length of the silver coated glass mandrel have been fabricated.

  11. In situ measurement using FBGs of process-induced strains during curing of thick glass/epoxy laminate plate

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani; Schmidt, Jacob Wittrup; Hattel, Jesper Henri;

    2012-01-01

    For large composite structures, such as wind turbine blades, thick laminates are required to withstand large in-service loads. During the manufacture of thick laminates, one of the challenges met is avoiding process-induced shape distortions and residual stresses. In this paper, embedded fibre...

  12. Crustal thickness variation beneath the Romanian seismic network from Rayleigh wave dispersion and receiver function analysis

    Science.gov (United States)

    Tataru, Dragos; Grecu, Bogdan; Zaharia, Bogdan

    2014-05-01

    Variations in crustal thickness in Romania where determined by joint inversion of P wave receiver functions (RFs) and Rayleigh wave group velocity dispersion. We present new models of shear wave velocity structure of the crust beneath Romanian broad band stations. The data set consist in more than 500 teleseismic earthquake with epicentral distance between 30° and 95°, magnitude greater than 6 and a signal-to-noise ratio greater than 3 for the P-wave pulse. Most epicenters are situated along the northern Pacific Rim and arrive with backazimuths (BAZs) between 0° and 135° at the Romanian seismic network. We combine receiver functions with fundamental-mode of the Rayleigh wave group velocities to further constrain the shear-wave velocity structure.To extract the group velocities we applied the Multiple Filter Technique analysis to the vertical components of the earthquakes recordings. This technique allowed us to identify the Rayleigh wave fundamental mode and to compute the dispersion curves of the group velocities at periods between 10 and 150 s allowing us to resolve shear wave velocities to a depth of 100 km. The time-domain iterative deconvolution procedure of Ligorrıa and Ammon (1999) was employed to deconvolve the vertical component of the teleseismic P waveforms from the corresponding horizontal components and obtain radial and transverse receiver functions at each broadband station. The data are inverted using a joint, linearized inversion scheme (Hermann, 2002) which accounts for the relative influence of each set of observations, and allows a trade-off between fitting the observations, constructing a smooth model, and matching a priori constraints. The results show a thin crust for stations located inside the Pannonian basin (28-30 km) and a thicker crust for those in the East European Platform (36-40 km). The stations within the Southern and Central Carpathian Orogen are characterized by crustal depths of ~35 km. For stations located in the Northern

  13. The group velocity variation of Lamb wave in fiber reinforced composite plate.

    Science.gov (United States)

    Rhee, Sang-Ho; Lee, Jeong-Ki; Lee, Jung-Ju

    2007-12-01

    Experimentally measured Lamb wave group velocities in composite materials with anisotropic characteristics are not the same as the theoretical group velocities which is calculated with the Lamb wave dispersion equation. This discrepancy arises from the fact that the angle between the group velocity direction and the phase velocity direction in anisotropic materials exists. Wave propagation in a composite material with anisotropic characteristics should be considered with respect to magnitude correction in addition to direction correction. In this study, S0 mode phase velocity dispersion curves are depicted with the variation of degree with respect to the fiber direction using a Lamb wave dispersion relation in the unidirectional, bidirectional, and quasi-isotropic composite plates. Slowness surface is sketched by the reciprocal value of the phase velocity curves. The magnitude and direction of the group velocity could be calculated from the slowness surface. The recalculated group velocities with consideration of the magnitude and direction from the slowness surface are compared with experimentally measured group velocities. The proposed method shows good agreements with theoretical and experimental results.

  14. Four dimensional variational data assimilation of species-resolved satellite-retrieved aerosol optical thickness

    Science.gov (United States)

    Nieradzik, Lars Peter; Elbern, Hendrik

    2010-05-01

    Aerosols play an increasingly important role in atmospheric modelling. They have a strong influence on the radiative transfer balance and a significant impact on human health. Their origin is various and so are its effects. Most of the measurement sites in Europe only account for an integrated aerosol load PMx (Particulate Matter of less than x μm in diameter) which does not give any qualitative information on the composition of the aerosol. Since very different constituents like mineral dust derived from desert storms and sea salt contribute to PMx it is necessary to make aerosol forcasts not only of load, but also type resolved. The source of information chosen for this study is the aerosol retrieval system SYNAER (SYNergetic AErosol Retrieval) from DLR-DFD that retrieves BLAOT (Boundary Layer Aerosol Optical Thickness) making use of both AATSR/SCIAMACHY and AVHRR/GOME-2 data respectively. Its strengths are a large spatial coverage, near real-time availability, and the classification of five intrinsic aerosol species, namely water-solubles, water-insolubles, soot, sea salt, and mineral dust which are furthermore size resolved in terms of modes. A widely known technique to enhance forecast skills of CTMs (Chemistry-Transport-Models) by ingesting in-situ and, especially, remote-sensing measurements is the method of four dimensional variational data assimilation (4Dvar). The EURAD-IM (EURopean Air pollution Dispersion - Inverse Model), containing a full adjoint gas-phase model, has been expanded with an adjoint of the MADE (Modal Aerosol Dynamics model for Europe) to optimise initial and boundary values for aerosols using 4Dvar. A forward and an adjoint radiative transfer model is driven by the EURAD-IM as mapping between BLAOT and internal aerosol species. Furthermore, its condensation scheme has been bypassed by an HDMR (High-Dimensional-Model-Representation) to ensure differentiability, and a time saving online NMC-module for the generation of the background

  15. The Effect of Luting Agents and Ceramic Thickness on the Color Variation of Different Ceramics against a Chromatic Background.

    Science.gov (United States)

    de Azevedo Cubas, Gloria Beatriz; Camacho, Guilherme Brião; Demarco, Flávio Fernando; Pereira-Cenci, Tatiana

    2011-07-01

    The aim of this study was to assess the influence of various ceramic thicknesses and luting agents on color variation in five ceramic systems. Fifteen disc-shaped ceramic specimens (11 mm diameter; shade A3) were fabricated with each of the six veneering ceramics tested, with 1, 1.5, or 2 mm thickness (n=5). Resin composite discs (Z-250, shade C4) were used as bases to simulate a chromatic background. The cementation of the veneers was carried out with an opaque resin-based cement (Enforce, shade C4), a resin-based cement (Enforce, shade A3), or without cement (C4, control group). Color differences (ΔE*) were determined using a colorimeter. Three-way ANOVA was used to analyze the data, followed by a Tukey post-hoc test (α=.05). The L*a*b* values of the ceramic systems were affected by both the luting agent and the ceramic thickness (Pceramics tested, regardless of the thickness (Pceramics and were independent of the luting agent used. The association of 2-mm thickness with opaque cement presented the strongest masking ability of a dark colored background when compared to a non- opaque luting agent and the other thicknesses tested.

  16. Choroidal Thickness Variation According to Refractive Error Measured by Spectral Domain-optical Coherence Tomography in Korean Children.

    Science.gov (United States)

    Lee, Geun Young; Yu, Sung; Kang, Hyun Gu; Kim, Jin Seon; Lee, Kyoo Won; Lee, Jung-Ho

    2017-04-01

    To assess choroidal thickness (CT) variation according to refractive errors using enhanced-depth imaging optical coherence tomography. Eighty-nine eyes (in 89 children) choroidal scans using enhanced-depth imaging-optical coherence tomography. CT was measured at the fovea and at 1 mm and 3 mm nasal (N1 and N3), temporal (T1 and T3), superior (S1 and S3), and inferior (I1 and I3) from the fovea. Mean foveal CTs were 346.86 µm, 301.97 µm, and 267.46 µm in the hyperopia, emmetropia, and myopia groups, respectively (p thickness in the emmetropia and myopia groups was greater than thickness at other areas, particularly the nasal and inferior choroids (p choroid was thicker than the nasal choroid, regardless of the refractive error. The thickest location in the hyperopia group was the fovea; however, the temporal choroid was thickest in the emmetropia and myopia groups.

  17. Choroidal Thickness Variation According to Refractive Error Measured by Spectral Domain-optical Coherence Tomography in Korean Children

    Science.gov (United States)

    Lee, Geun Young; Yu, Sung; Kang, Hyun Gu; Kim, Jin Seon; Lee, Kyoo Won

    2017-01-01

    Purpose To assess choroidal thickness (CT) variation according to refractive errors using enhanced-depth imaging optical coherence tomography. Methods Eighty-nine eyes (in 89 children) Korean children, CTs were greater in the hyperopia group than in the emmetropia and myopia groups. The temporal choroid was thicker than the nasal choroid, regardless of the refractive error. The thickest location in the hyperopia group was the fovea; however, the temporal choroid was thickest in the emmetropia and myopia groups.

  18. Study on the Thickness Change of Nickel-Plated Layer in Fabrication of the Silver Hollow Nickel Waveguides by the Outer-Coating Method of the Liquid Phase Process

    OpenAIRE

    2016-01-01

    A metallic hollow waveguide is promising fiber for the delivery of laser radiation. Thickness of the nickel plated layer for supporting of the waveguide in fabrication of a dielectric coated silver hollow nickel waveguide is very important factor. In this paper, the change characteristic in the thickness of the nickel plated layer along the length of the silver coated glass mandrel during fabricating the silver hollow nickel waveguide by the outer-coating method of the liquid phase process ha...

  19. Through Thickness Variation of Cross Shear Rolling Texture in Grain Oriented Silicon Steel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The texture inhomogeneity in cross shear rolled grain oriented Si steel was investigated by means of the through thickness texture analysis. For the chosen rolling reductions (55%, 66.5%) and mismatch speed ratios (1.0, 1.1,1.3), the deformation textures in various thickness layers consist of three major components, i.e. strong γ-fiber,medium α-fiber and weak η-fiber, and they show an asymmetrical distribution throughout the thickness. The effect of reduction on the texture gradient is found to be more significant at and near the center layer; however, the effect subsurface layers, that may favour the formation of a sharp Goss texture during the subsequent annealing.

  20. Variations of the crustal thickness in the Betic-Rif domain and their foreland regions, by P-Receiver Functions

    Science.gov (United States)

    Stich, D.; Mancilla, F.; Morales, J.; Martin, R.; Diaz, J.; Pazos, A.; Cordoba, D.; Pulgar, J. A.; Ibarra, P.; Harnafi, M.; Gonzalez-Lodeiro, F.

    2012-12-01

    To image the crustal structure of the Betic-Rif Range and the surrounding area we perform a P-receiver function study (PRF). We calculate PRFs at 110 broadband stations located in South Iberia Peninsula and North Morocco to obtain thickness and average Vp/Vs ratio for the Crust. The Crustal thickness values show strong lateral variations throughout the region. Crustal thicknesses vary between ~19 km and ~46 km. The Betic and Rif ranges are underlined by a thickened crust with crustal thicknesses between ~35 km and ~46 km, reaching the highest values in the contact between the Alboran Domain and External Zones. Southeast Iberia and Northeast Morocco are affected by significant crustal thinning, with crustal thicknesses ranging from ~19 km to ~30 km, with the shallowest Moho along the Mediterranean coast. The transition from thick to thin crust is coincident with the faults system of the Trans-Alboran Shear Zone. Toward the North, the Iberian Massif is an homogeneous domain of average 30-31 km crustal thickness and flat Moho discontinuity with low average Vp/Vs ratios ~1.72. Further south an extended domain, which includes the Atlas domain and its foreland regions, presents crustal thickness of 27-34km. Vp/Vs ratios in north Morocco show normal values of ~1.75 for most stations except for the Atlas domain, where several stations present low Vp/Vs ratios around 1.71. The obtained PRFs are migrated to depth building cross-section images to delineate the crustal mantle discontinuity (Moho) along the study area. In the migrated images, we include altogether ~11.200 PFRs to follow the Moho discontinuity from the Iberian Massif, in the North, along the Gribraltar arc towards the Moroccan Massif in the South. These images show how, in the North, the Iberian crust underthrust the Alboran domain along their contact with the observation of a slab, from the western limit until the 3°W longitude, reaching the maximum depth of ~70 km under the coast coincide with the

  1. Enamel thickness variation of deciduous first and second upper molars in modern humans and Neanderthals.

    Science.gov (United States)

    Fornai, Cinzia; Benazzi, Stefano; Svoboda, Jiří; Pap, Ildikó; Harvati, Katerina; Weber, Gerhard W

    2014-11-01

    Enamel thickness and dental tissue proportions have been recognized as effective taxonomic discriminators between Neanderthal and modern humans teeth. However, most of the research on this topic focused on permanent teeth, and little information is available for the deciduous dentition. Moreover, although worn teeth are more frequently found than unworn teeth, published data for worn teeth are scarce and methods for the assessment of their enamel thickness need to be developed. Here, we addressed this issue by studying the 2D average enamel thickness (AET) and 2D relative enamel thickness (RET) of Neanderthal and modern humans unworn to moderately worn upper first deciduous molars (dm(1)s) and upper second deciduous molars (dm(2)s). In particular, we used 3D μCT data to investigate the mesial section for dm(1)s and both mesial and buccal sections for dm(2)s. Our results confirmed previous findings of an Neanderthal derived condition of thin enamel, and thinner enamel in dm(1)s than dm(2)s in both Neanderthal and modern humans. We demonstrated that the Neanderthal 2D RET indices are significantly lower than those of modern humans at similar wear stages in both dm(1)s and dm(2)s (p Neanderthal unworn to moderately worn upper deciduous molars.

  2. Variation of Hardness and Modulus across thickness of Zr-Cu-Al Metallic Glass Ribbons

    Science.gov (United States)

    Z. Humberto Melgarejo; J.E. Jakes; J. Hwang; Y.E. Kalay; M.J. Kramer; P.M. Voyles; D.S. Stone

    2012-01-01

    We investigate through-thickness hardness and modulus of Zr50Cu45Al5 metallic glass melt-spun ribbon. Because of their thinness, the ribbons are challenging to measure, so we employ a novel nanoindentation based-method to remove artifacts caused by ribbon flexing and edge effects. Hardness and modulus...

  3. Global blending optimization of laminated composites with discrete material candidate selection and thickness variation

    DEFF Research Database (Denmark)

    Sørensen, Søren N.; Stolpe, Mathias

    2015-01-01

    to a distinct choice among predefined numbers of candidates. The laminate thickness is variable but the number of plies must be integer. We solve the convex mixed binary non-linear programming problem by an outer approximation cutting-plane method augmented with a few heuristics to accelerate the convergence...

  4. Along-Strike Electrical Conductivity Variations in the Incoming Plate and Shallow Forearc of the Cascadia Subduction Zone

    Science.gov (United States)

    Key, K.; Bedrosian, P.; Egbert, G. D.; Livelybrooks, D.; Parris, B. A.; Schultz, A.

    2015-12-01

    The Magnetotelluric Observations of Cascadia using a Huge Array (MOCHA) experiment was carried out to study the nature of the seismogenic locked zone and the down-dip transition zone where episodic tremor and slip (ETS) originates. This amphibious magnetotelluric (MT) data set consists of 8 offshore and 15 onshore profiles crossing from just seaward of the trench to the western front of the Cascades, with a north-south extent spanning from central Oregon to central Washington. The 71 offshore stations and the 75 onshore stations (red triangles in the image below) fit into the broader context of the more sparsely sampled EarthScope MT transportable array (black triangles) and other previous and pending MT surveys (other symbols). These data allows us to image variations in electrical conductivity along distinct segments of the Cascadia subduction zone defined by ETS recurrence intervals. Since bulk conductivity in this setting depends primarily on porosity, fluid content and temperature, the conductivity images created from the MOCHA data offer unique insights on fluid processes in the crust and mantle, and how the distribution of fluid along the plate interface relates to observed variations in ETS behavior. This abstract explores the across- and along-strike variations in the incoming plate and the shallow offshore forearc. In particular we examine how conductivity variations, and the inferred fluid content and porosity variations, are related to tectonic segmentation, seismicity and deformation patterns, and arc magma variations along-strike. Porosity inferred in the forearc crust can be interpreted in conjunction with active and passive seismic imaging results and may provide new insights on the origin of recently observed extremely high heat flow values. A companion abstract (Parris et al.) examines the deeper conductivity structure of the locked and ETS zones along the plate interface in order to identify correlations between ETS occurrence rates and inferred

  5. Genetic variations in the osteopontin promoters T-443C and G-156GG increase carotid intima–media thickness

    Science.gov (United States)

    Yueniwati, Yuyun; Yurina, Valentina; Sobah, Nurus; Rahayu, Endang

    2016-01-01

    Carotid intima–media thickness (CIMT) is a clear predictor of atherosclerosis. The increase of CIMT is affected by mutations in the osteopontin (OPN) promoters. The purpose of this study was to examine genetic variations in OPN promoters T-443C and G-156GG, identified in Javanese children with ischemic stroke parents, and to investigate their relationship with the increase of CIMT. A case–control analytic study was performed on 20 case and 12 control samples. Case samples were Javanese children aged between 10 to 21 years with ischemic stroke parents. Control samples were children with healthy parents. Mutations of T-443C and G-156GG were determined by employing polymerase chain reaction. Results of sequencing were analyzed using CLC Main Workbench 6.0. CIMT was defined using ultrasound. Genetic variations of T-443C were identified in six samples. Likewise, genetic variations of G-156GG were identified in six samples. Genetic variations in the OPN promoters T-443C and G-156GG were not potential risk factors in an increase of CIMT (P=0.654 and P=0.654). This study proves that genetic variations could be identified at the points of T-443C and G-156GG in children with ischemic stroke parents. Although statistically insignificant, the tendency to increase CIMT occurs in children with genetic variations. Children with ischemic stroke parents have thicker CIMT than children of healthy parents. PMID:27274305

  6. Effects of lateral variations in megaregolith thickness on predicted lunar seismic signals

    Science.gov (United States)

    Blanchette-Guertin, J.-F.; Johnson, C. L.; Lawrence, J. F.

    2015-12-01

    We use a modified phonon synthetic seismogram method to investigate the effects of laterally varying megaregolith thickness on the propagation of seismic energy and on the resulting seismic signals recorded at various epicentral distances from the source. We show that receivers located in large impact structures, with thin crust and thinner megaregolith, can record seismic signals that are less affected by high levels of scattering. In particular, receivers located away from the basin edge by a distance greater than or equal to the thickness of the surrounding megaregolith can record seismograms in which secondary arrivals containing important information about interior structure can be more readily identified. Seismic sources located beneath the near-surface scattering layer, such as deep lunar quakes, are also advantageous because the resulting seismograms are less affected by high levels of scattering than those from sources within the scattering layer or surface impacts.

  7. 选择镀镍金中镀金面积与厚度关系的研究与改善%Research and improvement on plating gold area and thickness in pattern plating nickel and gold

    Institute of Scientific and Technical Information of China (English)

    刘喆

    2012-01-01

    随着现代电子技术的不断发展,电路板中将有越来越多的镀镍金表面工艺,来满足开关、触点及耐摩擦等方面的要求。图形的分布不均给电路板镀镍金的表面处理带来了诸如金厚度、金表观等难以克服的缺陷。从电镀的原理方面入手,分析造成这些缺陷的原因,并给出相应的解决办法,为以后选择镀镍金为表面处理方式的产品的加工提供一种新的思路与方法。%As the development of modern electronic technology, there are more and more PCB which are manufactured with pattern plating nickel and gold to fulfill the requirements of switch, contact, friction and so on. The different plating area that distributed on different sides induces a lot of defects such as thickness and appearance of gold. Starting with the principle of electroplating, this paper analyses the reason and the solution of the defects, and provides a method of manufacturing the PCB that are treated as pattern plating nickel and gold.

  8. The effect of impurity on temperature variations in the refractive indices and thickness of TGS crystals

    Science.gov (United States)

    Stadnyk, V. Yo.; Andriyevsky, B. V.; Gaba, V. M.; Kogut, Z. A.

    2016-06-01

    Temperature dependences of optical path difference δΔi and the relative changes in thickness δ l i/ l of TGS crystals doped with L-valine are studied. Temperature dependences of the relative changes in refractive indices δ n i/( n-1) are calculated. The anisotropy coefficients of refractive indices An-1(T) and linear expansion Aα(T) are calculated, and a characteristic minimum of these dependences is found near the phase transition temperature.

  9. Constraints on lateral variations of lithospheric thickness and mantle viscosity from GNSS horizontal velocities of the BIFROST project

    Science.gov (United States)

    Steffen, Holger; Johansson, Jan; Kierulf, Halfdan Pascal; Kristiansen, Oddgeir; Lidberg, Martin; Tarasov, Lev

    2016-04-01

    The BIFROST (Baseline Inferences for Fennoscandian Rebound Observations Sea Level and Tectonics) project was started in 1993. The primary goal was to establish a new and useful three-dimensional measurement of crustal movement based on Global Navigation Satellite System (GNSS) observations, that is able to constrain models of the glacial isostatic adjustment (GIA) in Fennoscandia. Station velocities derived from analysis of observations at permanent GNSS stations in the Nordic countries and beyond have been published over the last 15 years. The latest GNSS-based 3D velocity field of Fennoscandia is a result of a re-processing of data from 1993 to 2014 from more than two hundred stations in northern Europe. It is computed using a state-of-the-art strategy. In this poster, we analyse the computed station velocities towards identification of lateral variations in lithospheric thickness and mantle viscosity in Fennoscandia. We therefore focus on the horizontal components. We compare observed velocities against velocities from a large set of GIA models. Preliminary results show that inclusion of lateral mantle viscosity variations in the model is necessary to explain distinct horizontal velocity patterns of the observed motion. However, some patterns can also be explained by strong lithospheric thickness variations, which requires an extended analysis in future.

  10. HST Spectral Mapping of L/T Transition Brown Dwarfs Reveals Cloud Thickness Variations

    CERN Document Server

    Apai, Daniel; Buenzli, Esther; Burrows, Adam; Reid, Iain N; Jayawardhana, Ray

    2013-01-01

    Most directly imaged giant exoplanets are fainter than brown dwarfs with similar spectra. To explain their relative underluminosity unusually cloudy atmospheres have been proposed. However, with multiple parameters varying between any two objects, it remained difficult to observationally test this idea. We present a new method, sensitive time-resolved Hubble Space Telescope near-infrared spectroscopy, to study two rotating L/T transition brown dwarfs (2M2139 and SIMP0136). The observations provide spatially and spectrally resolved mapping of the cloud decks of the brown dwarfs. The data allow the study of cloud structure variations while other parameters are unchanged. We find that both brown dwarfs display variations of identical nature: J- and H-band brightness variations with minimal color and spectral changes. Our light curve models show that even the simplest surface brightness distributions require at least three elliptical spots. We show that for each source the spectral changes can be reproduced with ...

  11. Potential vorticity and layer thickness variations in the flow around Jupiter's Great Red Spot and White Oval BC

    Science.gov (United States)

    Dowling, Timothy E.; Ingersoll, Andrew P.

    1988-01-01

    Using Voyager images, layer thickness variations in the flow around Jupiter's Great Red Spot (GRS) and White Oval BC were investigated by treating potential vorticity as a conserved tracer. Fluid trajectories around the GRS and the White Oval BC were calculated assuming the flow to be frictionless, adiabatic, hydrostatic, and steady in the reference frame of the vortex. The data obtained constitute a useful diagnostic which will help to differentiate between models of Jovian vortices. Implications of the observations were studied in the context of a one-layer quasi-geostrophic model in which a thin upper weather layer, which contains the vortex, is supported hydrostatically by a much deeper lower layer.

  12. Relation between physiological variation of renal function and carotid intima media thickness in non-diabetic individuals.

    Science.gov (United States)

    Bobbert, Thomas; Mai, Knut; Fischer-Rosinský, Antje; Osterhoff, Martin; Pfeiffer, Andreas F H; Spranger, Joachim

    2010-03-31

    Moderate to severe renal insufficiency and albuminuria have been shown to be independent risk factors for atherosclerosis. However, the association between renal function and intima media thick-ness (IMT) in non-diabetic individuals is less clear. We therefore investigated the relation between renal function, established cardiovascular risk factors and carotid intima media thickness in non-diabetic individuals. 853 non-diabetic participants were included in this project. Renal function was estimated using the simplified Modification of Diet in Renal Disease (MDRD) formulae, a refit MDRD equation for healthy persons (MDRD-1) or the Jellife 2 formula, an age independent estimate of glomerular filtration rate (GFR). Carotid arterial intima-media thickness was measured at the posterior wall of the common carotid artery and the bulbus (IMT(ACC), IMTB(Bulbus)). Weak correlations between IMT(ACC) or IMTB(Bulbus) and MDRD were found (r=-0.105, p= 0.002; r=-0.127, p<0.001). and similiar results were found for MDRD-1. However, adjustment of that relation for age modified the picture. While age was an independent predictor, MDRD or MDRD-1 were not further informative. Further adjustment for cardiovascular risk factors confirmed that relation. Correspondingly, GFR estimated by the age-independent formula Jellife 2 was not correlated with IMT. The results of this study indicate that variation of renal function within the normal range is not independently associated with carotid intima media thickness in non-diabetic individuals. Crude correlations between MDRD and IMT appear to reflect the inter-relation among age, eGFR and IMT.

  13. Creep Modeling in a Composite Rotating Disc with Thickness Variation in Presence of Residual Stress

    Directory of Open Access Journals (Sweden)

    Vandana Gupta

    2012-01-01

    Full Text Available Steady-state creep response in a rotating disc made of Al-SiC (particle composite having linearly varying thickness has been carried out using isotropic/anisotropic Hoffman yield criterion and results are compared with those using von Mises yield criterion/Hill's criterion ignoring difference in yield stresses. The steady-state creep behavior has been described by Sherby's creep law. The material parameters characterizing difference in yield stresses have been used from the available experimental results in literature. Stress and strain rate distributions developed due to rotation have been calculated. It is concluded that the stress and strain distributions got affected from the thermal residual stress in an isotropic/anisotropic rotating disc, although the effect of residual stress on creep behavior in an anisotropic rotating disc is observed to be lower than those observed in an isotropic disc. Thus, the presence of residual stress in composite rotating disc with varying thickness needs attention for designing a disc.

  14. Variations of midline facial soft tissue thicknesses among three skeletal classes in Central Anatolian adults.

    Science.gov (United States)

    Gungor, Kahraman; Bulut, Ozgur; Hizliol, Ismail; Hekimoglu, Baki; Gurcan, Safa

    2015-11-01

    Facial reconstruction is a technique employed in a forensic investigation as a last resort to recreate an individual's facial appearance from his/her skull. Forensic anthropologists or artists use facial soft tissue thickness (FSTT) measurements as a guide in facial reconstructions. The aim of this study was to develop FSTT values for Central Anatolian adults, taking into consideration sex and skeletal classes; first, to achieve better results obtaining the likenesses of deceased individuals in two or three-dimensional forensic facial reconstructions and, second, to compare these values to existing databases. Lateral cephalograms were used to determine FSTT values at 10 midline facial landmarks of 167 adults. Descriptive statistics were calculated for these facial soft tissue thickness values, and these values were compared to those reported in two other comparable databases. The majority of the landmarks showed sex-based differences. Males were found to have significantly larger landmark values than female subjects. These results point not only to the necessity to present data in accordance with sexual dimorphism, but also the need to consider that individuals from different geographical areas have unique facial features and that, as a result, geographical population-specific FSTT values are required.

  15. Anomalous thickness variation of the foam films stabilized by weak non-ionic surfactants.

    Science.gov (United States)

    Qu, Xuan; Wang, Liguang; Karakashev, Stoyan I; Nguyen, Anh V

    2009-09-15

    The constant thickness (H) of metastable free films of various non-ionic surfactant solutions was measured at surfactant concentrations less than the critical micelle concentrations or solubility limits with fixed 5x10(-5) M sodium chloride (NaCl) serving as the background electrolyte. The surfactants include n-pentanol, n-octanol, methyl isobutyl carbinol (MIBC), polypropylene glycol (PPG-400), tetraethylene glycol monooctyl ether (C(8)E(4)), and tetraethylene glycol monodecyl ether (C(10)E(4)). H was interferometrically measured. For each surfactant in this study, the H-versus-surfactant-concentration curve finds a peak at a concentration around 5x10(-6)-1x10(-5) M and a valley at a higher concentration. The measured H values were compared to those predicted from the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, which considers solely the contribution from electrostatic double-layer repulsion with van der Waals attraction being neglected in the present work. In determining the double-layer repulsion, the ionic strength was determined from the electrolytic conductivity measurement of the film-forming solutions and the surface potential was estimated from the zeta-potential measurement of air bubbles. It was found that the DLVO theory failed to explain the thickness variance with surfactant concentration, implying that additional non-DLVO attractive forces might be required to explain the experimental results. Finally, the possible origins of these attractive forces were discussed.

  16. Deep-rooted “thick skinned” model for the High Atlas Mountains (Morocco. Implications for the seismic Eurasia-Africa plate boundary region

    Directory of Open Access Journals (Sweden)

    Guiraud, M.

    2007-06-01

    Full Text Available Previous crustal models of the High Atlas suppose the existence of a mid-crustal detachment where all the surface thrusts merged and below which the lower crust was continuous. However, both seismic refraction data and gravity modeling detected a jump in crustal thickness between the High Atlas and the northern plains. Here we show that this rapid and vertical jump in the depth of Moho discontinuity suggests that a thrust fault may penetrate the lower crust and offset the Moho (deep-rooted “thick skinned” model. The distribution of Neogene and Quaternary volcanisms along and at the northern part of the High Atlas lineament can be related to the beginning of a partial continental subduction of the West African plate to the north underneath Moroccan microplate. Allowing from the complex problem of the plate boundary in the western zone of the Mediterranean, we propose to interpret the South-Atlasic fault zone as the actual northwestern boundary of the stable part of the African plate rather than the Azores-Gibraltar fault currently used.Los modelos geodinámicos existentes sobre la estructura profunda del alto Atlas suponen la existencia de un despegue medio-cortical donde convergen los cabalgamientos superficiales y bajo el cual la corteza inferior es continua. Los datos de sísmica de refracción y gravimetría, sin embargo, indican la existencia de una discontinuidad en el grosor de la corteza (profundidad del Moho bajo el Alto Atlas. En este artículo ponemos de manifiesto que este salto rápido en la profundidad del Moho puede ser causado por un cabalgamiento que penetra la corteza inferior, desplazando la base de la misma ("deeprooted thick skinned model". La distribución del volcanismo Neógeno y Cuaternario a lo largo de y al norte de la alineación del Alto Atlas pueden estar relacionados con el comienzo de una subducción continental parcial de la placa Africana occidental hacia el norte, bajo la microplaca marroquí. La expresi

  17. Detailed crustal thickness variations beneath the Illinois Basin area: Implications for crustal evolution of the midcontinent

    Science.gov (United States)

    Yang, Xiaotao; Pavlis, Gary L.; Hamburger, Michael W.; Marshak, Stephen; Gilbert, Hersh; Rupp, John; Larson, Timothy H.; Chen, Chen; Carpenter, N. Seth

    2017-08-01

    We present high-resolution imaging results of crustal and upper mantle velocity discontinuities across the Illinois Basin area using both common conversion point stacking and plane wave migration methods applied to P wave receiver functions from the EarthScope Ozark, Illinois, Indiana, and Kentucky experiment. The images reveal unusually thick crust (up to 62 km) throughout the central and southeastern Illinois Basin area. A significant Moho gradient underlies the NW trending Ste. Genevieve Fault Zone, which delineates the boundary between the Illinois Basin and Ozark Dome. Relatively thinner crust (convergent margin tectonics around 1.55-1.35 Ga; (3) by Late Precambrian magmatic underplating at the base of older crust, associated with the creation of the Eastern Granite-Rhyolite Province around 1.3 Ga; and (4) through crustal "relamination" during an episode of Proterozoic flat-slab subduction beneath the Illinois Basin, possibly associated with the Grenville Orogeny.

  18. Relative influence of surficial, climatic, and plate tectonic processes on the development of thick Paleoproterozoic quartz arenite successions

    Science.gov (United States)

    Corcoran, P.; Bynoe, L.

    2010-12-01

    Quartz arenites are significant components of the rock record and appear to be most abundant during specific time intervals in Earth history. Thick quartz arenite successions are typical in Precambrian strata and have been associated with extensive cratonization during the late Archean to early Proterozoic. These supermature sandstones can also be attributed to the intense weathering conditions of early Earth’s atmosphere, source rocks rich in quartz, recycling and diagenesis, or simply the higher preservation potential of quartz compared with other minerals. Modern quartz-rich sands develop in low relief settings where high residence times contribute to chemical breakdown of labile grains. The lack of land vegetation during the Precambrian would have precluded confined sedimentation patterns and stabilization of soils, both of which enhance sediment residence times. Thus, the generation of first-cycle late Archean quartz arenites in fault-controlled, high relief basins necessitates periods of intense chemical weathering. The inferred change from a greenhouse to oxygenated atmosphere at around 2.3-2.2 Ga could have been the major control on the relative change to thinner units of pure sandstones with time. In order to test this hypothesis, detailed facies and compositional analyses are being conducted on the ca. 2.2 Ga Bar River Formation of the Huronian Supergroup, Canada. Four groups comprise Huronian stratigraphy, three of which contain basal glaciogenic conglomerates, followed by mudstone-dominated then quartz-rich formations. It has been suggested that these tripartite cycles could have been climatically controlled. Detailed facies analysis of the 500-750 m thick quartz arenite indicates shallow water, wave-influenced settings, akin to shoreface environments along extensive stable shelves. Thin mudstone interbeds, representing brief periods of suspension sedimentation, have been sampled for geochemical analysis in order to determine the degree of chemical

  19. Variation of interface trap level charge density within the bandgap of 4H-SiC with varying oxide thickness

    Indian Academy of Sciences (India)

    Sanjeev K Gupta; A Azam; J Akhtar

    2011-01-01

    Interfacial characteristics of metal oxide-silicon carbide (MOSiC) structure with different thickness of SiO2, thermally grown in steam ambient on Si-face of 4H-SiC (0 0 0 1) substrate were investigated. Variations in interface trapped level density (Dit) was systematically studied employing high-low (H-L) frequency – method. It was found that the distribution of Dit within the bandgap of 4H-SiC varied with oxide thickness. The calculated Dit value near the midgap of 4H-SiC remained almost stable for all oxide thicknesses in the range of 109 –1010 cm-2 eV-1. The Dit near the conduction band edge had been found to be of the order of 1011 cm-2 eV-1 for thicker oxides and for thinner oxides Dit was found to be the range of 1010 cm-2 eV-1. The process had direct relevance in the fabrication of MOS-based device structures.

  20. Wear and Durability Variation Compared with Thickness of Cutting Inserts Coated with AlTiN Thin Films

    Science.gov (United States)

    Bădănac, A.; Lupescu, O.; Manole, V.; Ungureanu, C.; Popa, M.

    2016-08-01

    During the use of cutting tools in the cutting process, they lose their exploitation indices after a certain range of working, due to the occurrence of wear phenomenon. Wear occurs due to the parameters variation of the working regimes, fact that involves in order to not overcoming the limits of the maximum allowable wear, application of methods, to increase their durability. In order to increase the cutting tools durability are known various methods of surface coating with materials with better properties than the material of the cutting tool. In the case of cutting inserts, are known many researches concerning their coating by vacuum deposition of thin layers of metal, methods as: physical vapour deposition and chemical vapour deposition. The coatings realized by vacuum deposition have gained special attention because of their unique physical and chemical properties for example excellent resistance to oxidation at high temperatures. The main characteristics which are checked in the deposition process of thin layers are: thickness and the wear resistance. In this study the authors carried out researches regarding the coatings of AlTiN in thin layers, on surface of some cutting inserts. It was measured the variation of the wear and durability compared with the thickness of AlTiN thin layers deposited on the cutting inserts.

  1. Variation in Campylobacter MLST Subtypes Detected from Chickens on Three Different Plating Media

    Science.gov (United States)

    The objective of this study was to compare subtypes of Campylobacter jejuni and coli detected on three discreet selective Campylobacter plating media to determine if different media select for different subtypes. Fifty ceca and fifty carcasses (n=100, representing 50 flocks) were collected from the...

  2. A new clinical unit for digital radiography based on a thick amorphous Selenium plate: Physical and psychophysical characterization

    Energy Technology Data Exchange (ETDEWEB)

    Rivetti, Stefano; Lanconelli, Nico; Bertolini, Marco; Acchiappati, Domenico [Alma Mater Studiorum, Physics Department, University of Bologna, 40127 Bologna, Italy and S.C. di Fisica Sanitaria ' ' Azienda USL di Modena' ' 41100 Modena (Italy); Alma Mater Studiorum, Physics Department, University of Bologna, 40127 Bologna (Italy); Arcispedale Santa Maria Nuova, 42123 Reggio Emilia (Italy); S.C. di Fisica Sanitaria ' ' Azienda USL di Modena' ' 41100 Modena (Italy)

    2011-08-15

    Purpose: Here, we present a physical and psychophysical characterization of a new clinical unit (named AcSelerate) for digital radiography based on a thick a-Se layer. We also compared images acquired with and without a software filter (named CRF) developed for reducing sharpness and noise of the images and making them similar to images coming from traditional computed radiography systems. Methods: The characterization was achieved in terms of physical figures of merit [modulation transfer function (MTF), noise power spectra (NPS), detective quantum efficiency (DQE)], and psychophysical parameters (contrast-detail analysis with an automatic reading of CDRAD images). We accomplished measurements with four standard beam conditions: RAQ3, RQA5, RQA7, and RQA9. Results: The system shows an excellent MTF (about 50% at the Nyquist frequency). The DQE is about 55% at 0.5 lp/mm and above 20% at the Nyquist frequency and is almost independent from exposure. The contrast-detail curves are comparable to some of the best published data for other systems devoted to imaging in general radiography. The CRF filter influences both the MTF and NPS, but it does lead to very small changes on DQE. Also the visibility of CDRAD details is basically unaltered, when the filter is activated. Conclusions: As normally happens with detector based on direct conversion, the system presents an excellent MTF. The improved efficiency caused by the thick layer allows getting good noise characteristics and DQE results better (about 10% on average) than many of the computed radiography (CR) systems and comparable to those obtained by the best systems for digital radiography available on the market.

  3. Аsymptotic solution of a class thermoelasticity nonclassical boundary value problems for the package of an orthotropic plate of variable thickness

    Directory of Open Access Journals (Sweden)

    Aghalovyan M.L.

    2014-03-01

    Full Text Available We solve the non-classical boundary value problem for an orthotropic packet when on one of its front surface the corresponding components of the stress tensor are equal to zero and sets the value of the displacement vector. The task, in particular, is modeling the behavior of the lithospheric plates of the Earth, or a specific region of the earth's crust subject to tectonic movements of the fixed seismic stations, GPS and other measuring instruments. On the basis of three-dimensional equations of thermo-elasticity asymptotic method derived recurrence equations allow for a package of orthotropic layers of varying thickness. We derive recursive formulas for determining the components of the stress tensor and the displacement vector.

  4. Accommodation-induced variations in retinal thickness measured by spectral domain optical coherence tomography

    Science.gov (United States)

    Fan, Shanhui; Sun, Yong; Dai, Cuixia; Zheng, Haihua; Ren, Qiushi; Jiao, Shuliang; Zhou, Chuanqing

    2014-09-01

    To research retinal stretching or distortion with accommodation, accommodation-induced changes in retinal thickness (RT) in the macular area were investigated in a population of young adults (n=23) by using a dual-channel spectral domain optical coherence tomography (SD-OCT) system manufactured in-house for this study. This dual-channel SD-OCT is capable of imaging the cornea and retina simultaneously with an imaging speed of 24 kHz A-line scan rate, which can provide the anatomical dimensions of the eye, including the RT and axial length. Thus, the modification of the RT with accommodation can be calculated. A significant decrease in the RT (13.50±1.25 μm) was observed during maximum accommodation. In the 4 mm×4 mm macular area centered at the fovea, we did not find a significant quadrant-dependent difference in retinal volume change, which indicates that neither retinal stretching nor distortion was quadrant-dependent during accommodation. We speculate that the changes in RT with maximum accommodation resulted from accommodation-induced ciliary muscle contractions.

  5. The Laser Welding with Hot Wire of 316LN Thick Plate Applied on ITER Correction Coil Case

    CERN Document Server

    Fang, Chao; Wu, Weiyue; Wei, Jing; Zhang, Shuquan; Li, Hongwei; Dolgetta, N; Libeyre, P; Cormany, C; Sgobba, S

    2014-01-01

    ITER correction coil (CC) cases have characteristics of small cross section, large dimensions, and complex structure. The cases are made of heavy thick (20 mm), high strength and high toughness austenitic stainless steel 316LN. The multi-pass laser welding with hot wire technology is used for the case closure welding, due to its low heat input and deformation. In order to evaluate the reliability of this welding technology, 20 mm welding samples with the same groove structure and welding depth as the cases were welded. High purity argon was used as the shielding gas to prevent oxidation because of the narrowness and depth of the weld. In this paper investigation of, microstructure characteristics and mechanical properties of welded joints using optimized welding parameters are presented. The results show that the base metal, fusion metal, and heat affected zone (HAZ) are all have fully austenitic microstructure, and that the grain size of fusion metal was finer than that of the base metal. The welding resulte...

  6. Diurnal variation in central corneal thickness and intraocular pressure in eyes with pseudoexfoliation syndrome without glaucoma

    Directory of Open Access Journals (Sweden)

    Stuart Keel

    2014-01-01

    Full Text Available Aim: The aim was to ascertain if any differences exist in diurnal central corneal thickness (CCT and intra-ocular pressure (IOP between eyes with pseudoexfoliation (PXF syndrome without glaucoma and eyes with no ocular pathology. A secondary aim was to determine whether there was a significant relationship between CCT and IOP. Settings and Design: This study was a prospective design conducted within a hospital setting. Materials and Methods: The experimental group consisted of seven participants with bilateral PXF (14 eyes and the control group comprised of 15 participants (30 eyes. Testing included CCT and IOP measured at four different times on one given day (8.00 a.m.; 11 a.m.; 2 p.m. and 5 p.m.. Statistical Analysis: The data were analyzed with the generalized linear latent mixed model. Results: PXF eyes displayed a significantly thinner overall mean CCT (520 μm compared to controls (530 μm. Furthermore, a significant reduction in CCT and IOP occurred in the PXF group from 8 a.m. to 5 p.m. The mean overall IOP in PXF eyes was significantly lower than the control group. A significant association between IOP and CCT was also found in PXF eyes. Conclusions: Displaying a significantly thinner mean CCT highlights the importance of measuring CCT in an ophthalmic clinical setting as to avoid falsely underestimated IOP measurements in such a high-risk glaucoma population. Furthermore, a statistically significant correlation between IOP and CCT in PXF eyes suggests that the reduction in CCT that occurred in PXF eyes between 8 a.m. and 5 p.m. may be partly responsible for the reduction in IOP measurements.

  7. A 3D shell-like approach using element-free Galerkin method for analysis of thin and thick plate structures

    Institute of Scientific and Technical Information of China (English)

    Yu Yin; Lin-Quan Yao; Yang Cao

    2013-01-01

    A new efficient meshless method based on the element-free Galerkin method is proposed to analyze the static deformation of thin and thick plate structures in this paper.Using the new 3D shell-like kinematics in analogy to the solid-shell concept of the finite element method,discretization is carried out by the nodes located on the upper and lower surfaces of the structures.The approximation of all unknown field variables is carried out by using the moving least squares (MLS) approximation scheme in the in-plane directions,while the linear interpolation is applied through the thickness direction.Thus,different boundary conditions are defined only using displacements and penalty method is used to entorce the essential boundary conditions.The constrained Galerkin weak form,which incorporates only displacement degrees of freedom (d.o.f.s),is derived.A modified 3D constitutive relationship is adopted in order to avoid or eliminate some self-locking effects.The numeric efficiency of the proposed meshless formulation is illustrated by the numeric examples.

  8. Experimental investigation of transient temperature characteristic in high power fiber laser cutting of a thick steel plate

    Science.gov (United States)

    Phi Long, Nguyen; Matsunaga, Yukihiro; Hanari, Toshihide; Yamada, Tomonori; Muramatsu, Toshiharu

    2016-10-01

    Experiment of temperature measurement was performed to investigate the transient temperature characteristics of molten metal during laser cutting. The aim of this study was to establish a method for measuring the surface temperature variation near the molten pool correlated with changes in cutting parameters. The relationship between temperature inside the kerf cut and characteristic of the cut surface was investigated by using thermography and thermocouples. Results show strong correlations between the transient temperatures and the thermal image for different cutting conditions. In addition, two-color thermometer has been used to obtain radiation intensity emitted from the irradiating zone as a function of operating conditions. Experiments have shown that one can detect the cutting quality by characterization of the surface temperature during laser cutting process.

  9. Topography caused by mantle density variations: observation-based estimates and models derived from tomography and lithosphere thickness

    Science.gov (United States)

    Steinberger, Bernhard

    2016-04-01

    Large-scale topography may be due to several causes, including (1) variations in crustal thickness and density structure, (2) oceanic lithosphere age differences, (3) subcrustal density variations in the continental lithosphere and (4) convective flow in the mantle beneath the lithosphere. The last contribution in particular may change with time and be responsible for continental inundations; distinguishing between these contributions is therefore important for linking Earth's history to its observed geological record. As a step towards this goal, this paper aims at such distinction for the present-day topography: the approach taken is deriving a `model' topography due to contributions (3) and (4), along with a model geoid, using a geodynamic mantle flow model. Both lithosphere thickness and density anomalies beneath the lithosphere are inferred from seismic tomography. Density anomalies within the continental lithosphere are uncertain, because they are probably due to variations in composition and temperature, making a simple scaling from seismic to density anomalies inappropriate. Therefore, we test a number of different assumptions regarding these. As a reality check, model topography is compared, in terms of both correlation and amplitude ratio, to `residual' topography, which follows from observed topography after subtracting contributions (1) and (2). The model geoid is compared to observations as well. Comparatively good agreement is found if there is either an excess density of ≈0.2 per cent in the lithosphere above ≈150 km depth, with anomalies below as inferred from tomography, or if the excess density is ≈0.4 per cent in the entire lithosphere. Further, a good fit is found for viscosity ≈1020 Pa s in the asthenosphere, increasing to ≈1023 Pa s in the lower mantle above D'. Results are quite dependent on which tomography models they are based on; for some recent ones, topography correlation is ≈0.6, many smaller scale features are matched

  10. Inter -and intraobserver variation of ultrasonographic cartilage thickness assessments in small and large joints in healthy children

    Directory of Open Access Journals (Sweden)

    Stenbøg Elisabeth

    2009-06-01

    Full Text Available Abstract Background There is an increasing interest among pediatric rheumatologist for using ultrasonography (US in the daily clinical examination of children with juvenile idiopathic arthritis (JIA. Loss of joint cartilage may be an early feature of destructive disease in JIA. However, US still needs validation before it can be used as a diagnostic bedside tool in a pediatric setting. This study aims to assess the inter- and intraobserver reliability of US measurements of cartilage thickness in the joints of healthy children. Methods 740 joints of 74 healthy Caucasian children (27 girls/47 boys, aged 11.3 (7.11 – 16 years were examined with bilateral US in 5 preselected joints to assess the interobserver variability. In 17 of these children (6 girls/11 boys, aged 10.1(7.11–11.1 years, 170 joints was examined in an intraobserver sub study, with a 2 week interval between the first and second examination. Results In this study we found a good inter- and intraobserver agreement expressed as a coefficient of variation (CV less than 10% in the knee (CV = 9.5%interobserver and 5.9%intraobservserI, 9.3%intraobserverII respectively for the two intraobserver measurements and fairly good for the MCP joints (CV = 11.9%interobserver, 12.9%intraobserverI and 11.9%intraobsevrerII. In the ankle and PIP joints the inter- and intraobserver agreement was within an acceptable limit (CV26%. We found no difference in cartilage thickness between the left and right extremity in the investigated joints. Conclusion We found a good inter -and intraobserver agreement when measuring cartilage thickness with US. The inter- and intraobserver variation seemed not to be related to joint size. These findings suggest that positioning of the joint and the transducer is of major importance for reproducible US measurements. We found no difference in joint cartilage thickness between the left and right extremity in any of the examined joint of the healthy children. This is an

  11. Leaf thickness controls variation in leaf mass per area (LMA) among grazing-adapted grasses in Serengeti.

    Science.gov (United States)

    Griffith, Daniel M; Quigley, Kathleen M; Anderson, T Michael

    2016-08-01

    Leaf mass per area (LMA) is a primary plant functional trait that represents the cost of constructing a leaf. Ultimately, plants modify LMA by altering leaf thickness (LT), leaf dry matter content (LDMC), or both. While LMA can be modified through both of these constituents, studies of LMA have found that there is variation in whether LT or LDMC changes are responsible for LMA-and the relationships change depending on the species or functional groups being compared. In this study, we used a phylogenetic framework to determine that evolutionary shifts in LMA are driven by LT, and not LDMC, among 45 Serengeti grass species. We considered two alternative hypotheses that could result in evolutionary correlation of LMA on LT but not LDMC: either (1) LT is more labile than LDMC-and is therefore a less costly means to change LMA or (2) LDMC is tightly coupled to a different dimension of leaf variation (e.g., leaf hydraulics), leaving LT as the source of variation in LMA. LT was not more labile than LDMC, leading us to conclude that the evolution of LMA has been shaped by LT because LDMC is responding to other demands on leaf physiology. We speculate that leaf hydraulics provide this constraint on LDMC. The decoupling of LDMC from LT may allow plants to better optimize resource allocation in ecosystems where gradients in light competition, herbivory, and aridity place competing demands on leaf economics.

  12. Variation of b and p values from aftershocks sequences along the Mexican subduction zone and their relation to plate characteristics

    Science.gov (United States)

    Ávila-Barrientos, L.; Zúñiga, F. R.; Rodríguez-Pérez, Q.; Guzmán-Speziale, M.

    2015-11-01

    Aftershock sequences along the Mexican subduction margin (between coordinates 110ºW and 91ºW) were analyzed by means of the p value from the Omori-Utsu relation and the b value from the Gutenberg-Richter relation. We focused on recent medium to large (Mw > 5.6) events considered susceptible of generating aftershock sequences suitable for analysis. The main goal was to try to find a possible correlation between aftershock parameters and plate characteristics, such as displacement rate, age and segmentation. The subduction regime of Mexico is one of the most active regions of the world with a high frequency of occurrence of medium to large events and plate characteristics change along the subduction margin. Previous studies have observed differences in seismic source characteristics at the subduction regime, which may indicate a difference in rheology and possible segmentation. The results of the analysis of the aftershock sequences indicate a slight tendency for p values to decrease from west to east with increasing of plate age although a statistical significance is undermined by the small number of aftershocks in the sequences, a particular feature distinctive of the region as compared to other world subduction regimes. The b values show an opposite, increasing trend towards the east even though the statistical significance is not enough to warrant the validation of such a trend. A linear regression between both parameters provides additional support for the inverse relation. Moreover, we calculated the seismic coupling coefficient, showing a direct relation with the p and b values. While we cannot undoubtedly confirm the hypothesis that aftershock generation depends on certain tectonic characteristics (age, thickness, temperature), our results do not reject it thus encouraging further study into this question.

  13. Static characterization of bump-type gas foil bearing: intergration of top foil 2-D thick plate model%基于二维厚板模型的波箔片轴承静特性

    Institute of Scientific and Technical Information of China (English)

    刘占生; 徐方程; 张广辉; 曹智选

    2012-01-01

    The 2-D (two-dimensional) thick plate finite element model for top foil was developed. By using coupled finite element mothod and finite difference method, the com- pressible gas lubricated Reynolds equation and the film thickness equation were solved cou- pling together. Predictions of minimum gas film thickness for increasing static loads at two speeds were obtained for bearing mid-plane and edge of bump-type gas foil bearing. The nu- merical results of this finite element model were compared with 1-D (one-dimensional) beam model model, 2-D shin shell model and test data. The results indicate that the minimum film thickness of three models agree well with test data at bearing min-plane, but at bearing edge, the accuracy of 2-D thick plate model is the highest due to its shear effect. 1-D beam model can not reflect film thickness variation along the bearing length direction because it on- ly considers the circumferential direction. The study in this paper established the theoretical foundation of dynamic characteristics research of bump-type gas foil bearing.%建立平箔片的二维厚板有限元模型,运用有限单元法和有限差分法耦合求解Reynolds方程和气膜厚度方程,研究了在两个工作转速下气体波箔片轴承在中截面和边缘处最小气膜厚度随轴承承载力变化规律.通过数值仿真对该模型、一维梁模型、二维薄壳模型和文献实验数据进行对比分析,结果表明:在轴承中截面处,3个模型的最小气膜厚度仿真结果都与实验结果符合得很好,但在轴承边缘处,由于二维厚板模型考虑了平箔片的剪切效应,因此其最小气膜厚度比二维薄壳模型的结果更接近实验值,而一维梁模型只考虑轴承圆周方向,因此不能体现气膜厚度沿轴承长度方向的变化规律.通过研究,为分析箔片轴承动力学特性奠定了理论基础.

  14. Variation in Campylobacter Multilocus Sequence Typing Subtypes from Chickens as Detected on Three Plating Media.

    Science.gov (United States)

    Berrang, M E; Ladely, S R; Meinersmann, R J; Line, J E; Oakley, B B; Cox, N A

    2016-11-01

    The objective of this study was to compare subtypes of Campylobacter jejuni and Campylobacter coli detected on three selective Campylobacter plating media to determine whether each medium selected for different subtypes. Fifty ceca and 50 carcasses (representing 50 flocks) were collected from the evisceration line in a commercial broiler processing plant. Campylobacter was cultured and isolated from cecal contents and carcass rinses on Campy-Cefex, Campy Line, and RF Campylobacter jejuni/coli agars. When a positive result was obtained with all three media, one colony of the most prevalent morphology on each medium was selected for further analysis by full genome sequencing and multilocus sequence typing. Sequence types were assigned according to PubMLST. A total of 49 samples were positive for Campylobacter on all three media. Forty samples contained only C. jejuni , three had only C. coli , and both species were detected in six samples. From 71% of samples, Campylobacter isolates of the same sequence type were recovered on all three media. From 81.6% of samples, isolates were all from the same clonal complex. From significantly fewer samples (26%, P Campylobacter jejuni/coli . From one sample, three sequence types were detected. In most cases, all three plating media allowed detection of the same type of Campylobacter from complex naturally contaminated chicken samples.

  15. Corrosion Behavior of Top and Bottom Surfaces for Single-Side and Double-Side Friction Stir Welded 7085-T7651 Aluminum Alloy Thick Plate Joints

    Science.gov (United States)

    Xu, Weifeng; Zhang, Wei; Wu, Xiaoli

    2017-03-01

    Thick plate joints of 7085-T7451 aluminum alloy were obtained through both single-side and double-side friction stir welding (SS or DS-FSW). The chloride ions effects on the corrosion behavior of the top and bottom surfaces of the joints were examined by cyclic potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). Results show that the corrosion susceptibility was suppressed significantly in the weld nugget zone, while the base material and heat-affected zone were prone to be corrosion attacked. For the SS-FSWed joint, the top surface showed a higher corrosion resistance than that of the bottom surface, but the larger corrosive heterogeneity was observed between the top and bottom surfaces compared with the two welds of DS-FSWed joint, which was confirmed by the morphology of corrosion attack. A deep insight on the microstructure of the joints indicates that the intermetallic particles played a key role in the corrosion behavior of the FSWed AA7085 aluminum alloy joints in chloride solution.

  16. Effects of the two-step ageing treatment on the microstructure and properties of 7B04 alloy pre-stretched thick plates

    Institute of Scientific and Technical Information of China (English)

    LI Zhihui; XIONG Baiqing; ZHANG Yong'an; ZHU Baohong; WANG Feng; LIU Hongwei

    2007-01-01

    The effects of the two-step ageing parameters (temperature and time) on the mechanical properties and electrical conductivity of 7B04 (Al-Zn-Mg-Cu) pre-stretched thick plates were studied. The results reveal that the initial T1 ageing contributes a major increase of the tensile strength, and the 0.2% proof stress value reaches 482 MPa after ageing for 7 h at 115℃. Behavioral differences in the tensile properties of the alloy after the two-step ageing treatment were less with the first-step ageing at 115℃ for different time periods (7, 14, and 21 h). The effects of the second ageing parameters on the properties and microstructure of the 7B04 alloy were remarkable. TEM analysis of the samples aged at Temper I (7 h at 115℃ + 12 h at 160℃) and Temper Ⅱ (7 h at 115℃ + 16 h at 165℃) indicates that two kinds of phases, i.e. η' and η phases,precipitate from the matrix and efficiently improve the tensile strength of the alloy, and the grain boundary precipitates are coarse and discrete. There are obvious precipitate free zones (PFZs) along the grain boundary in the microstructure of the alloy after the two-step ageing treatment.

  17. Corrosion Behavior of Top and Bottom Surfaces for Single-Side and Double-Side Friction Stir Welded 7085-T7651 Aluminum Alloy Thick Plate Joints

    Science.gov (United States)

    Xu, Weifeng; Zhang, Wei; Wu, Xiaoli

    2017-01-01

    Thick plate joints of 7085-T7451 aluminum alloy were obtained through both single-side and double-side friction stir welding (SS or DS-FSW). The chloride ions effects on the corrosion behavior of the top and bottom surfaces of the joints were examined by cyclic potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). Results show that the corrosion susceptibility was suppressed significantly in the weld nugget zone, while the base material and heat-affected zone were prone to be corrosion attacked. For the SS-FSWed joint, the top surface showed a higher corrosion resistance than that of the bottom surface, but the larger corrosive heterogeneity was observed between the top and bottom surfaces compared with the two welds of DS-FSWed joint, which was confirmed by the morphology of corrosion attack. A deep insight on the microstructure of the joints indicates that the intermetallic particles played a key role in the corrosion behavior of the FSWed AA7085 aluminum alloy joints in chloride solution.

  18. Tungsten Inert Gas and Friction Stir Welding Characteristics of 4-mm-Thick 2219-T87 Plates at Room Temperature and -196 °C

    Science.gov (United States)

    Lei, Xuefeng; Deng, Ying; Yin, Zhimin; Xu, Guofu

    2014-06-01

    2219-T87 aluminum alloy is widely used for fabricating liquid rocket propellant storage tank, due to its admirable cryogenic property. Welding is the dominant joining method in the manufacturing process of aerospace components. In this study, the tungsten inert gas welding and friction stir welding (FSW) characteristics of 4-mm-thick 2219-T87 alloy plate at room temperature (25 °C) and deep cryogenic temperature (-196 °C) were investigated by property measurements and microscopy methods. The studied 2219 base alloy exhibits a low strength plane anisotropy and excellent room temperature and cryogenic mechanical properties. The ultimate tensile strength values of TIG and FSW welding joints can reach 265 and 353 MPa at room temperature, and 342 and 438 MPa at -196 °C, respectively. The base metal consists of elongated deformed grains and many nano-scaled θ (Al2Cu) aging precipitates. Fusion zone and heat-affected zone (HAZ) of the TIG joint are characterized by coarsening dendritic grains and equiaxed recrystallized grains, respectively. The FSW-welded joint consists of the weld nugget zone, thermo-mechanically affected zone (TMAZ), and HAZ. In the weld nugget zone, a micro-scaled sub-grain structure is the main microstructure characteristic. The TMAZ and HAZ are both characterized by coarsened aging precipitates and elongated deformed grains. The excellent FSW welding properties are attributed to the preservation of the working structures and homogenous chemical compositions.

  19. Fatigue properties for FSW and MIG welded joints of thickness plate aluminum alloy%厚板铝合金FSW和MIG焊接接头疲劳性能

    Institute of Scientific and Technical Information of China (English)

    杨新岐; 吴铁; 张家龙; 秦红珊

    2012-01-01

    对厚度10 mm的6082-T6铝合金搅拌摩擦焊(FSW)和MIG焊接接头的疲劳强度进行了试验研究,并与6082-T6母材疲劳性能进行了对比分析.结果表明,6082-T6母材的疲劳S-N曲线最高、MIG焊接接头S-N曲线度最低,而FSW接头的疲劳S-N曲线近似位于两者之间;在高应力区FSW疲劳强度低于MIG焊接接头、而在低应力区高于MIG焊接接头.大部分FSW试样疲劳裂纹启始于焊缝根部的"弱连接"缺陷,采用机械加工去掉1.4 mm厚度焊缝根部材料后,FSW疲劳强度明显提高并接近母材数据.厚板6082-T6铝合金FSW焊缝根部质量控制是影响疲劳性能的关键因素.%The fatigue properties of FSW and MIG welded joints for AA6082-T6 aluminum alloy of 10 mm thickness were investigated by the fatigue S-N curves testing method,and these prperties were also compared to that of AA6082-T6 base material.It was shown that the fatigue S-N curve of AA6082-T6 base material was the highest,the S-N curve of MIG welded joints was the lowest,and the S-N curve of FSW joint was between the two curves.In high stress range,the fatigue strength of FSW was lower than that of MIG welded joints,while in low stress range,it was higher than the MIG welded joints.It indicated that most of the FSW specimens were initially fractured at the weld,caused by the "weak-bonding" defects and the fatigue strength of FSW joint increased apparently,which is close to the values of base material after removing one layer of weld root material with thickness of 1.4 mm.Thus it can be verified that the quality of the weld root sites for the single-side FSW welded joints of AA6082-T6 aluminum alloys thick plate should be the key factor to influence the fatigue properties of FSW joint.

  20. EFFECT OF CHEMISTRY VARIATIONS IN PLATE AND WELD FILLER METAL ON THE CORROSION PERFORMANCE OF NI-CR-MO ALLOYS

    Energy Technology Data Exchange (ETDEWEB)

    D.V. Fix

    2006-02-07

    The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would change if heats of these alloys were prepared using several variations in the composition of the elements even though still in the range specified in B 575. All the material used in this report were especially prepared at Allegheny Ludlum Co. Seven heats of plate were welded with seven heats of wire. Immersion corrosion tests were conducted in a boiling solution of sulfuric acid plus ferric sulfate (ASTM G 28 A) using both as-welded (ASW) coupons and solution heat-treated (SHT) coupons. Results show that the corrosion rate was not affected by the chemistry of the materials in the range of the standards.

  1. Effect of Chemistry Variations in Plate and Weld Filler Metal on the Corrosion Performance of Ni-Cr-Mo Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fix, D V; Rebak, R B

    2006-02-05

    The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would change if heats of these alloys were prepared using several variations in the composition of the elements even though still in the range specified in B 575. All the material used in this report were especially prepared at Allegheny Ludlum Co. Seven heats of plate were welded with seven heats of wire. Immersion corrosion tests were conducted in a boiling solution of sulfuric acid plus ferric sulfate (ASTM G 28 A) using both as-welded (ASW) coupons and solution heat-treated (SHT) coupons. Results show that the corrosion rate was not affected by the chemistry of the materials in the range of the standards.

  2. Angular shear plate

    Science.gov (United States)

    Ruda, Mitchell C [Tucson, AZ; Greynolds, Alan W [Tucson, AZ; Stuhlinger, Tilman W [Tucson, AZ

    2009-07-14

    One or more disc-shaped angular shear plates each include a region thereon having a thickness that varies with a nonlinear function. For the case of two such shear plates, they are positioned in a facing relationship and rotated relative to each other. Light passing through the variable thickness regions in the angular plates is refracted. By properly timing the relative rotation of the plates and by the use of an appropriate polynomial function for the thickness of the shear plate, light passing therethrough can be focused at variable positions.

  3. Fold-and-thrust belt evolution influenced by along and across strike thickness variations: new insights from brittle-ductile centrifuge analogue models

    Science.gov (United States)

    Santolaria Otin, Pablo; Harris, Lyal; Casas, Antonio; Soto, Ruth

    2014-05-01

    Using a new centrifuge analogue modelling approach, 38 models were performed to study the influence of along and across strike thickness variations of a ductile-brittle layered sequence on the kinematics and deformation style of fold-and-thrust belts. Four different series, changing the brittle-ductile thickness ratio in models with i) constant thickness, ii) across strike varying thickness, iii) along strike varying thickness and iv) along and across-strike varying thickness, were performed. The brittle sedimentary cover was simulated by "Moon Sand™", regular fine-grained quartz sand coated by polymer and synthetic rubber binders, allowing layers to be placed vertically in the centrifuge (impossible with normal sand). The ductile décollement (evaporites) was simulated by silicone putty (Crazy Aaron Enterprise's Thinking Putty™). Models were run step by step in a high-acceleration centrifuge attaining 900 g, what allows to drastically reduce the experimental time. In addition to surface observation and serial cross-sections at the end of the models, CT scans portray the progressive 3- and 4-dimensional evolution of several models. With constant thickness, the increase of the brittle-ductile ratio results in the decrease of the number of structures where shortening is accommodated and the development of structures does not follow a linear sequence. Across-strike thickness variations trigger the location of deformation towards the wedge front, precluding the emplacement of structures in the hinterland. Along-strike thickness changes result in the lateral variation of the number of structure and a differential displacement of the deformation front. The occurrence of oblique structures is enhanced in wedges with across and along strike thickness variations where, in addition, rotational domains are observed. Comparison with the South Pyrenean Central Unit, in the Southern Pyrenees, characterized by a west- and southward thinning of the pretectonic Mesozoic series

  4. 中厚板轧后冷却正规阶段温度场变分解%VARIATIONAL SOLUTION OF CONTINUOUS COOLING TEMPERATURE FIELD FOR PLATE AFTER ROLLING DURING FULLY DEVELOPED REGIME

    Institute of Scientific and Technical Information of China (English)

    章顺虎; 赵德文; 刘南君; 高彩茹

    2013-01-01

    该文从导热微分方程和定解条件出发,设定了预先满足边界条件的试函数,并结合拉格朗日乘子法,构建了里兹温度场泛函的广义表达式,经泛函变分,首次获得了中厚板轧后冷却正规阶段温度场的变分解,该解为板厚δ,换热系数α,比热cp,冷却时间t,热传导率λ,钢板密度p,开冷温度T0,水温Tf的函数.该解与分离变量法获得的解析解比较表明,该解对分离变量法获得的解析解具有较高的逼近程度,两者最大误差不超过7℃.该文导出的平均温度出现在x=0.577δ的位置上,心表温差随着冷却时间的增加而减少.该文中变分解法未报道.%From the heat conduction,differential equations and definite conditions,a trial function which satisfies boundary condition in advance is set.With the Lagrange multiplier method,the generalized expression of Ritz temperature field functional is first established.The variational solution of temperature field for a plate after rolling during fully developed regime is then first obtained by functional variation.It is a function of plate thick δ,heat transfer coefficient a,specific heat cp,cooling time t,thermal conductivity λ,plate density p,starting cooling temperature T0,and water temperature Tf.The comparison between the variational results and those analytical results by the separation variable method shows that the present results have high forecast precision and the maximum error between them is no more than 7%.It is also deduced that the average temperature occurs at the location of x=0.577δ,and the temperature difference between plate surface and centre along the thick direction decreases as the cooling time increases.The method in the present paper has not been reported yet.

  5. A Variationally Formulated Problem of the Stationary Heat Conduction in a Plate with Radiation Reduction Factor Increased under Temperature

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2016-01-01

    dependence of the absorption factor on the local intensity of this radiation. Furthermore, it can be a significant dependence of this factor on the local value of the material temperature, reflecting the above-mentioned relationship between the absorption of electromagnetic wave energy and the excitation of material microparticles. This process can be described by Boltzmann distribution function that comprises the energy to activate microparticles and the local value of temperature.This paper presents a variational formulation of the nonlinear problem of stationary heat conduction in a plate for the case when the radiation reduction factor in relation to the Bouguer law depends on the local temperature. This formulation includes a functional that can have several fixed points corresponding to different steady states of the plate temperature. Analysis of the properties of this functional enabled us to identify the stationary points, which correspond to the realized temperature distribution in the plate.

  6. Compositional variation within thick (>10 m) flow units of Mauna Kea Volcano cored by the Hawaii Scientific Drilling Project

    Science.gov (United States)

    Huang, Shichun; Vollinger, Michael J.; Frey, Frederick A.; Rhodes, J. Michael; Zhang, Qun

    2016-07-01

    Geochemical analyses of stratigraphic sequences of lava flows are necessary to understand how a volcano works. Typically one sample from each lava flow is collected and studied with the assumption that this sample is representative of the flow composition. This assumption may not be valid. The thickness of flows ranges from 100 m. Geochemical heterogeneity in thin flows may be created by interaction with the surficial environment whereas magmatic processes occurring during emplacement may create geochemical heterogeneities in thick flows. The Hawaii Scientific Drilling Project (HSDP) cored ∼3.3 km of basalt erupted at Mauna Kea Volcano. In order to determine geochemical heterogeneities in a flow, multiple samples from four thick (9.3-98.4 m) HSDP flow units were analyzed for major and trace elements. We found that major element abundances in three submarine flow units are controlled by the varying proportion of olivine, the primary phenocryst phase in these samples. Post-magmatic alteration of a subaerial flow led to loss of SiO2, CaO, Na2O, K2O and P2O5, and as a consequence, contents of immobile elements, such as Fe2O3 and Al2O3, increase. The mobility of SiO2 is important because Mauma Kea shield lavas divide into two groups that differ in SiO2 content. Post-magmatic mobility of SiO2 adds complexity to determining if these groups reflect differences in source or process. The most mobile elements during post-magmatic subaerial and submarine alteration are K and Rb, and Ba, Sr and U were also mobile, but their abundances are not highly correlated with K and Rb. The Ba/Th ratio has been used to document an important role for a plagioclase-rich source component for basalt from the Galapagos, Iceland and Hawaii. Although Ba/Th is anomalously high in Hawaiian basalt, variation in Ba abundance within a single flow shows that it is not a reliable indicator of a deep source component. In contrast, ratios involving elements that are typically immobile, such as La/Nb, La

  7. Design, synthesis and DSSC performance of o-fluorine substituted phenylene spacer sensitizers: effect of TiO2 thickness variation.

    Science.gov (United States)

    Bhim Raju, Telugu; Vaghasiya, Jayraj V; Afroz, Mohammad Adil; Soni, Saurabh S; Iyer, Parameswar Krishnan

    2016-10-19

    The influence of TiO2 film thickness on the performance of DSSCs with a new series of dyes having ortho-fluorine substituted phenyl spacers and different donor moieties is reported. Optical, electrochemical, molecular orbital and photovoltaic properties were studied by varying the TiO2 thickness (9 and 12 μm) using these dyes. The thickness variation of TiO2 films had a significant effect on the open circuit voltage (Voc), short circuit current (Jsc) and efficiency. The Jsc and Voc of dye 1b with a TiO2 film thickness of 12 μm (8.91 mA cm(-2) and 0.63 V) were larger than those of the 9 μm film thickness device (8.40 mA cm(-2) and 0.57 V). This could be due to the variation in the thickness of the TiO2 film. However, at an optimized thickness of the TiO2 film (12 μm), 1b exhibited the highest power conversion efficiency (η) of 4.0% (average 3.6%). This highest efficiency value for 1b from 3.3% to 4.0% without using any co-absorbents was solely based on changing the thickness of the TiO2 film. In addition 1b had a planar structure, whereas dyes 2b and 3b had three and two dimensional structures. The optimized geometry calculation of o-fluoro phenyl π-spacer dyes was ascertained by density functional theory (DFT) using the B3LYP/631G(d,p) basis set. These results reveal that dye 1b has higher efficiency due to the deeper HOMO level and it exhibited better charge transfer from donor to acceptor, compared to the other dyes.

  8. Numerical solution of the free vibration of functionally graded material moderately thick circular plates by shooting method%FGM中厚圆板轴对称自由振动的打靶法求解

    Institute of Scientific and Technical Information of China (English)

    李清禄; 张靖华; 李世荣

    2016-01-01

    The free vibration of FGMmoderately thick circular plates was investigated.A FGM plate consisting of metal and ceramic was considered in the study.Based on the geometric equation,physical equation and equilibrium equation of thick plates,taking into account the transverse shearing deformation,the free vibration equation of axisymmetric FGM thick circular plates was derived in terms of the middle surface angles of rotation and lateral displacement.The material properties of the plate were assumed to vary continuously in the thickness direction according to a power law.By using the shooting method to solve the coupled ordinary differential equations with different boundary conditions,the natural frequencies of FGMthick circular plates were obtained numerically.The effects of material gradient property,thickness ratio and boundary conditions on the natural frequencies were discussed in detail.%研究了由陶瓷和金属两种材料组成的功能梯度材料(FGM)中厚圆板的自由振动问题。基于考虑横向剪切变形中厚板的几何方程、物理方程及平衡方程,建立了以中面转角和横向位移为基本未知量的功能梯度中厚圆板轴对称自由振动问题的控制方程;假定功能梯度中厚圆板的材料性质方向按照幂函数连续变化规律;采用打靶法数值求解所得非线性两点边值问题出,获得了多种边界下功能梯度中厚圆板的无量纲自然频率以及振动模态。讨论了材料梯度指数、板的厚度以及边界条件对自然频率的影响。

  9. RESEARCH ON THICKNESS DEVIATION CRITERIA OF STEEL PLATE IN STEEL STRUCTURE CODE%钢结构规范中钢板厚度偏差问题的研究

    Institute of Scientific and Technical Information of China (English)

    陈会荣

    2012-01-01

    Thickness is a main factor affecting the bearing capacity of steel plate. If the thickness deviation of steel plate is not clear, potential safety hazard may exist or unnecessary waste may be caused. Due to the fact that allowable thickness deviation of steel plate is not unified in national standards, supervision and construction units may choose different criteria during comprehension and implementation of these standards, causing relatively obvious errors. Rational proposals are put forward after comparison of steel plate thicknesses between Code for design of steel structures (GB 50017-2003) and Code for acceptance of construction quality of steel structures(GB 50205-2001).%钢板的厚度尺寸是影响承载力的主要因素,如果板厚尺寸偏差不明确,不是造成安全隐患,就是造成不必要的浪费.在钢板厚度允许偏差上,由于国家标准的不统一,使得在工程监理及施工单位的理解和执行中,选择规范不同而造成误差.通过对比《钢结构设计规范》(GB 50017-2003)、《钢结构工程施工质量验收规范》(GB 50205-2001)等规范中钢板厚度允许偏差,提出合理化建议.

  10. 25/17MN双动厚板冲压液压机的电气控制系统%Electric control system of 25/17MN double motion hydraulic press punching thick plate

    Institute of Scientific and Technical Information of China (English)

    谭利红

    2001-01-01

    Electric control system of 25/17MN double motion hydraulic press punching thick plate and parameters operation manner have been introduced with analysis of graphic interface reality.%介绍了25/17MN双动厚板冲压液压机的电气控制系统及其系统中的参数处理方式,并对图形界面的实时性进行了分析。

  11. 极板厚度对电容边缘效应影响的理论和仿真分析%Simulation and Analysis of the Influence of Plate Thickness on Capacitive Edge Effect

    Institute of Scientific and Technical Information of China (English)

    雷建华

    2013-01-01

    The influence of plate thickness on capacitor edge effect is analyzed theoretically,and then the electromagnetic field distribution of parallel plate capacitor is simulated with the software of ANSYS. The results show that the theoretical analysis agrees well with simulations. The capacitor effect increases as the thickness increasing. Therefore,it is necessary to reduce the plate thickness in the real design,in order to save the cost of materials and reduce the edge effect as well.%理论分析了极板厚度对电容边缘效应的影响,并利用ANSYS有限元仿真软件分析平行板电容器的电磁场分布。研究发现,理论分析和仿真结果非常吻合,边缘效应随着极板厚度的增大而增大。因此,在实际设计中,需要在工艺的可行性基础上,尽可能减小极板厚度,既可以节省材料又能减小边缘效应带来的影响。

  12. ICESat Observations of Seasonal and Interannual Variations of Sea-Ice Freeboard and Estimated Thickness in the Weddell Sea, Antarctica (2003-2009)

    Science.gov (United States)

    Yi, Donghui; Robbins, John W.

    2010-01-01

    Sea-ice freeboard heights for 17 ICESat campaign periods from 2003 to 2009 are derived from ICESat data. Freeboard is combined with snow depth from Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) data and nominal densities of snow, water and sea ice, to estimate sea-ice thickness. Sea-ice freeboard and thickness distributions show clear seasonal variations that reflect the yearly cycle of growth and decay of the Weddell Sea (Antarctica) pack ice. During October-November, sea ice grows to its seasonal maximum both in area and thickness; the mean freeboards are 0.33-0.41 m and the mean thicknesses are 2.10-2.59 m. During February-March, thinner sea ice melts away and the sea-ice pack is mainly distributed in the west Weddell Sea; the mean freeboards are 0.35-0.46 m and the mean thicknesses are 1.48-1.94 m. During May-June, the mean freeboards and thicknesses are 0.26-0.29 m and 1.32-1.37 m, respectively. The 6 year trends in sea-ice extent and volume are (0.023+/-0.051) x 10(exp 6)sq km/a (0.45%/a) and (0.007+/-1.0.092) x 10(exp 3)cu km/a (0.08%/a); however, the large standard deviations indicate that these positive trends are not statistically significant.

  13. Analytical solution for multilayer plates using general layerwise plate theory

    Directory of Open Access Journals (Sweden)

    Vuksanović Đorđe M.

    2005-01-01

    Full Text Available This paper deals with closed-form solution for static analysis of simply supported composite plate, based on generalized laminate plate theory (GLPT. The mathematical model assumes piece-wise linear variation of in-plane displacement components and a constant transverse displacement through the thickness. It also include discrete transverse shear effect into the assumed displacement field, thus providing accurate prediction of transverse shear stresses. Namely, transverse stresses satisfy Hook's law, 3D equilibrium equations and traction free boundary conditions. With assumed displacement field, linear strain-displacement relation, and constitutive equations of the lamina, equilibrium equations are derived using principle of virtual displacements. Navier-type closed form solution of GLPT, is derived for simply supported plate, made of orthotropic laminae, loaded by harmonic and uniform distribution of transverse pressure. Results are compared with 3D elasticity solutions and excellent agreement is found.

  14. 计及板厚的平板电容器边缘电场特性%Characteristics of Edge Electric Field of Plate Capacitor Relating to its Thickness

    Institute of Scientific and Technical Information of China (English)

    吴锐; 袁长迎

    2015-01-01

    电容器一般视为不计板厚的理想元件,但实际上板厚对其电场分布存在着较大的影响。利用施瓦兹﹣克利斯多菲变换得到忽略板厚时平板电容器的边缘场强分布,再利用有限元模拟得到计及板厚时平板电容器的边缘场强分布。通过比较与分析,得出了边缘场强随板厚的变化关系以及边缘定点处的场强理想值误差。%The caPacitor is generally regarded as the ideal element regardless of its thickness,but,it actually has a great influence on the electric field. This article gets the distribution of edge electric field ignoring the Plate thickness by taking advantage of Schwarz ﹣ Christoffel transformation. As for the different thicknesses of the caPac-itor,the distribution of edge electric field can be obtained by the use of the finite element simulation. We can ob-tain that the changes in relations between Plate thickness and electric field,as well as the errors of the ideal value in Point through comParison and analysis.

  15. Influence of temperature on threshold stress for reorientation of hydrides and residual stress variation across thickness of Zr-2.5Nb alloy pressure tube

    Energy Technology Data Exchange (ETDEWEB)

    Singh, R.N. [Materials Science, Technology and Society, Malmo University, SE20506 (Sweden) and Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)]. E-mail: ram.singh@ts.mah.se; Lala Mikin, R. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Roorkee 247 667, Uttaranchal (India); Dey, G.K. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Sah, D.N. [Post Irradiation Examination Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Batra, I.S. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Stahle, P. [Materials Science, Technology and Society, Malmo University, SE20506 (Sweden)

    2006-12-15

    Threshold stress, {sigma} {sub th}, for reorientation of hydrides in cold worked and stress-relieved (CWSR) Zr-2.5Nb pressure tube material was determined in the temperature range of 523-673 K. Using tapered gage tensile specimen, mean value of {sigma} {sub th} was experimentally determined by two methods, half thickness method and area compensation method. The difference between local values of {sigma} {sub th} measured across the thickness of the tube and the mean {sigma} {sub th} values yielded the residual stress variation across the tube thickness. It was observed that both the mean threshold stress and residual stress decrease with increase in reorientation temperature. Also, the maximum value of residual stresses was observed near the midsection of the tube.

  16. A method of computing the transient temperature of thick walls from arbitrary variation of adiabatic-wall temperature and heat-transfer coefficient

    Science.gov (United States)

    Hill, P R

    1958-01-01

    A method of calculating the temperature of thick walls has been developed in which the time series and the response to a unit triangle variation of surface temperature concepts are used, together with essentially standard formulas for transient temperature and heat flow into thick walls. The method can be used without knowledge of the mathematical tools of its development. The method is particularly suitable for determining the wall temperature in one-dimensional thermal problems in aeronautics where there is a continuous variation of the heat-transfer coefficient and adiabatic-wall temperature. The method also offers a convenient means for solving the inverse problem of determining the heat-flow history when temperature history is known.

  17. In-process tool force and rotation variation to control sheet thickness change in friction stir welding of magnesium alloys

    Science.gov (United States)

    Buffa, Gianluca; Fratini, Livan; Simoncini, Michela; Forcellese, Archimede

    2016-10-01

    Two different in-process control strategies, developed in order to produce sound joints in AZ31 magnesium alloy by Friction Stir Welding on sheet blanks with a non-uniform thickness, are presented and compared. To this purpose, sheets with dip or hump were machined and welded by either changing the rotational speed or the tool plunging in order to keep constant the vertical force occurring during welding. The mechanical strength of the joints was measured in the zones where the sheets before welding were characterised by different thicknesses. The sheets welded by the two different strategies are characterized by very similar ultimate tensile strength values. Finally, the results showed that the two approaches permit to successfully weld sheets with non-uniform thickness with a reduced loss in the mechanical strength.

  18. Simulation of the development and interaction of instabilities in a relativistic electron beam under variation of the beam wall thickness

    Energy Technology Data Exchange (ETDEWEB)

    Badarin, A. A.; Kurkin, S. A. [Saratov State University (Russian Federation); Koronovskii, A. A. [Yuri Gagarin State Technical University (Russian Federation); Rak, A. O. [Belorussian State University of Informatics and Radioelectronics (Belarus); Hramov, A. E., E-mail: hramovae@gmail.com [Saratov State University (Russian Federation)

    2017-03-15

    The development and interaction of Bursian and diocotron instabilities in an annular relativistic electron beam propagating in a cylindrical drift chamber are investigated analytically and numerically as functions of the beam wall thickness and the magnitude of the external uniform magnetic field. It is found that the interaction of instabilities results in the formation of a virtual cathode with a complicated rotating helical structure and several reflection regions (electron bunches) in the azimuthal direction. It is shown that the number of electron bunches in the azimuthal direction increases with decreasing beam wall thickness and depends in a complicated manner on the magnitude of the external magnetic field.

  19. Design and Check of Face Gear Plate Variator%圆齿盘变速器的设计与校核

    Institute of Scientific and Technical Information of China (English)

    张桂华; 丁明成

    2011-01-01

    Face gear variator is a new gear variator and it is composed with external gear plate and face gear plate. The external gear plate is a column normal gear with very narrow gear width and the face gear plate is constituted with gear tooth of several circles. Several grade rotate speed can be achieved by a pair of gear driving of the face gear variator. The procedure of design and check of the face gear variator is detailedly introduced and that it attains the standard of gear driving of 9 grade accuracy indicator is proved. It is novel in mode, briefness in structure, flexible in placement and low in cost and it especially suites to the medium and low rotate speed.%圆齿盘变速器是一种新型齿轮式变速器,它由外齿盘和圆齿盘组成.外齿盘是齿宽很短的圆柱标准齿轮盘,圆齿盘由圆截面(端面)上若干圈轮齿形成.只有一对齿轮传动的圆齿盘变速器可以实现若干级变速.较详细介绍了圆齿盘变速器的设计与校核过程,证明它达到了一般齿轮传动的9级精度指标要求.它样式新颖、结构简单、放置灵活、制造成本低廉,特别适用于中低速传动的场合.

  20. Research on labial and lingual alveolar bone plate thickness of the mandibular anterior teeth by CBCT%下颌前牙唇舌侧骨壁厚度的锥形束 CT 研究

    Institute of Scientific and Technical Information of China (English)

    朱娟芳; 田雪丽; 田丽萍; 杜田丰; 王茜; 马艳蕊

    2016-01-01

    目的:应用锥形束 CT(CBCT)测量下颌前牙唇舌侧骨壁厚度,为即刻种植提供临床指导。方法选取132例正常牙合个体的 CBCT 图像,对其下颌前牙进行研究。测量根尖处、根尖1/4、根中1/2、根颈1/4处的唇舌侧骨壁厚度,比较左、右侧及性别之间骨壁厚度的差异。结果下前牙左右侧同名牙相应骨壁厚度无差异。除根颈1/4处外,舌侧骨壁较唇侧厚。中切牙、侧切牙和尖牙在根颈1/4处,唇侧骨壁厚度>2 mm 的比例分别占0、0和1.51%。在根中1/4处,分别占0.76%、1.44%和3.79%。性别对舌侧骨壁厚度有影响。结论应用 CBCT 建立了正常牙合个体下颌前牙区唇舌侧骨壁厚度的参考值,为即刻种植提供临床指导依据。%Objective To investigate labial and lingual alveolar bone plate thickness of the mandibular anterior teeth by using cone-beam computed tomography (CBCT),in order to provide a reference for immediate implantation.Methods 132 individuals with normal occlusion were examined with CBCT,and their mandibular anterior teeth were analyzed.The labial and lingual alveolar bone plate thickness at the level of the apical,1/4 of the apical,1/2 of the middle and 1/4 of the cervical were measured.The differences of the thickness were compared among the side and gender.Results There were no significant differences between the left and right sides. Except on the 1/4 of the cervical,the thickness of lingual bone plate was thicker than that of labial bone plate.The frequency of the thickness of the labial bone larger than 2 mm on the 1/4 of the cervical of the center incisor,lateral incisor,and canine were 0,0 and 1.5 1%,respectively,and on 1/4 of the middle were 0.76%,1.44% and 3.79%,respectively.The lingual bone plate thickness showed significant difference between genders.Conclusion Reference values of alveolar bone plate thickness in anterior teeth of normal occlusion were established by using CBCT,which can

  1. Influence of thickness variation on perpendicular magnetic anisotropy features of the [co/pt]n multilayer frame.

    Science.gov (United States)

    Lee, Ja Bin; An, Gwang Guk; Yang, Seung Mo; Hong, Jin Pyo

    2014-11-01

    We report the structural and magnetic properties of a [Co/Pt] multilayer matrix as a function of Pt thickness. Increasing Pt thickness allows for the formation of a well-aligned fcc (111) CoPt3 structure in a [Co/Pt]n multilayer geometry, where the clear appearance of main (111) peak of CoPt3 measured using the X-ray diffraction patterns was confirmed. High-resolution transmission electron microscopy images, along with the corresponding fast Fourier transform patterns displayed the ordered structure with clear 6-fold symmetric diffraction spots. The c/a lattice constant ratio of 0.949 was calculated by utilizing the XRD and, demonstrating the presence of a well-aligned CoPt3 structure. The Pt thickness-dependent saturation magnetization (M(s)) values for the in- and out-of-plane M-H hysteresis loops obtained by vibrating sample magnetometer measurements showed distinctly opposite trends. The increase in the out-of-plane M(s) value with increasing Pt thickness seems to originate from the enhanced perpendicular orbital moment of the proper CoPt3 structure.

  2. Interpreting Thickness Changes in the Diabetic Macula: The Problem of Short-Term Variation in Optical Coherence Tomography–Measured Macular Thickening (An American Ophthalmological Society Thesis)

    Science.gov (United States)

    Browning, David J.

    2010-01-01

    Purpose: To estimate the short-term variability of macular thickness in eyes with refractory and regressed diabetic macular edema (DME). Methods: In this retrospective review of consecutive cases from a retina practice, optical coherence tomography (OCT) measurements of macular thickness were extracted from the clinical charts of patients with refractory DME and regressed DME. Variation in macular thickness was defined as maximal central subfield mean thickness (CSMT) minus minimal CSMT during a period of observation in which clinical macular status did not change. Results: There were 36 eyes of 29 patients in the refractory DME group and 93 eyes of 93 patients in the regressed DME group. Median intervals during which macular status was unchanged and OCTs were collected were 7 months for the refractory DME group and 22 months for the regressed DME group. Baseline CSMTs were 321 μm for the refractory DME group and 217 μm for the regressed DME group. The median variation in CSMT was 89 μm for the refractory DME group and 19 μm for the regressed DME group. Results for total macular volume paralleled those for CSMT. Conclusions: In consonance with eyes having treatment-naïve DME, eyes with refractory DME have short-term fluctuation in macular thickness larger than OCT measurement variability. In eyes with regressed DME, short-term fluctuation is less than in eyes with refractory DME, yet can also exceed measurement variability. This information is clinically important in deciding whether subsequent treatment is indicated. PMID:21212849

  3. INFLUENCE OF VARIATIONS OF THE CONDUCTIVITY OF UPPER LAYER OF TWO-LAYER SAMPLE ON OF PHASE INTRODUCED ELECTROMOTIVE FORCE OF SUPERIMPOSED TRANSDUCER OF EDDY CURRENT THICKNESS METER

    Directory of Open Access Journals (Sweden)

    A. V. Chernyshev

    2017-01-01

    Full Text Available In carrying out eddy current thickness measurement of two-layer conductive objects one from the interfering factors is the presence of variations in the value of the electrical conductivity of the material of the upper layer (coating when moving from point to point on the surface of object of control or when passing from one object of control to another. The aim of this work is to evaluate the accuracy of determining the thickness of the conductive coating disposed on a conducting ferromagnetic basis, using the phase method of eddy current testing. The reason of the error is variation of the electrical conductivity of the material of coating.Determination of the error is based on calculations using known analytical expressions for the loop with current of sinusoidal form arranged over the infinite half space with a covering as a thin layer. Selected in calculating electromagnetic parameters of coating and substrate approximately correspond to the case -chromium layer on a nickel base. Calculations are performed for different frequencies of current passed through coil.It is shown that at reduction of frequency of the current passes through the coil the error is reduced. The value of the lowest possible operating frequency of the excitation current is determined by the condition of absence influence on the phase introduced into the superimposed transducer emf variations in the thickness of the basis.To reduce the indicated error it is proposed to determine, on the basis of phase method at a relatively high frequency transducer current excitation, conductivity of the material of coating. After this, at a low frequency excitation current and using phase method, the coating thickness is determined, taking into consideration the previously determined value of the conductivity of coating. Also discussed ways to improve the accuracy of phase measurements in the MHz region of the excitation current frequency. 

  4. Edge-wave-driven durable variations in the thickness of the surfactant film and concentration of surface floats

    Energy Technology Data Exchange (ETDEWEB)

    Averbukh, Elena [Nizhny Novgorod State Technical University n.a. R.E. Alekseev, Minin St. 24, 603950 Nizhny Novgorod (Russian Federation); Kurkina, Oksana, E-mail: okurkina@hse.ru [Nizhny Novgorod State Technical University n.a. R.E. Alekseev, Minin St. 24, 603950 Nizhny Novgorod (Russian Federation); National Research University Higher School of Economics, 25/12 Bol' shaya Pecherskaya St., 603155 Nizhny Novgorod (Russian Federation); Kurkin, Andrey [Nizhny Novgorod State Technical University n.a. R.E. Alekseev, Minin St. 24, 603950 Nizhny Novgorod (Russian Federation); Soomere, Tarmo, E-mail: soomere@cs.ioc.ee [Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn (Estonia)

    2014-01-03

    By employing a simple model for small-scale linear edge waves propagating along a homogeneous sloping beach, we demonstrate that certain combinations of linear wave components may lead to durable changes in the thickness of the surfactant film, equivalently, in the concentration of various substances (debris, litter) floating on the water surface. Such changes are caused by high-amplitude transient elevations that resemble rogue waves and occur during dispersive focusing of wave fields with a continuous spectrum. This process can be treated as an intrinsic mechanism of production of patches in the surface layer of an otherwise homogeneous coastal environment impacted by linear edge waves.

  5. 3D gravity modelling reveals off-axis crustal thickness variations along the western Gakkel Ridge (Arctic Ocean)

    Science.gov (United States)

    Schmidt-Aursch, Mechita C.; Jokat, Wilfried

    2016-11-01

    Near-orthogonal ultra-slow (13.3 mm yr- 1 to 6.5 mm yr- 1) sea floor spreading in the absence of large transform faults make the Arctic Gakkel Ridge ideally suited for the study of magmatic processes. To enable this, we generated a three-dimensional gravity model of crustal thickness over the ridge and parts of the adjacent Nansen and Amundsen basins west of 65° E. The model shows that oceanic crust accreted prior to chrons C5/C6 is generally very thin (1-3 km). Magnetic anomalies over this thin crust are highly variable both parallel and perpendicular to the ridge axis. This is the result of amagmatic or weakly volcanic spreading that started with the opening of the basins 56 Ma ago. The separation of Greenland from Svalbard at chron C5/C6 led to the inflow of North Atlantic mantle into the western Eurasia Basin leading to a change in the mantle convection system and the establishment of a magmatic dichotomy along the Gakkel Ridge. Robust magmatism was established in the Western Volcanic Zone (6° 30‧ W-3° 30‧ E), leading to creation of a 6.6 km thick igneous crust, characterized by a strong positive axial magnetic anomaly, numerous volcanic cones, and widespread thick mid-ocean ridge basalts. The transition to the neighbouring Sparsely Magmatic (3° 30‧ E-29° E) and Eastern Volcanic (29° E-85° E) zones is sharp. Peridotites cover the central valley and the inner rift flanks, the central magnetic anomaly vanishes and crustal thickness decreases to 1-4 km. Transverse basement ridges, extending for as much as 100 km into the adjacent basins, intersect the central valley. Although partly of tectonic origin, the transverse ridges are also an expression of long-living magmatic centres, as revealed by increased magnetic anomaly intensities and local thickening of the crust to values as great as 5.9 km.

  6. Effects of soil moisture retention on ice distribution and active layer thickness subject to seasonal ground temperature variations in a dry loess terrace in Adventdalen, Svalbard.

    Science.gov (United States)

    Schuh, Carina; Frampton, Andrew; Christiansen, Hanne

    2017-04-01

    The active layer constitutes an important part of permafrost environments. Thermal and hydrological processes in the active layer determine local phenomena such as erosion and hydrological and ecosystem changes, and can have important implications for the global carbon-climate feedback. Permafrost degradation usually starts with a deepening of the active layer, followed by the formation of a talik and the subsequent thawing of permafrost. An increasing active layer thickness is therefore regarded as an indicator of permafrost degradation. The importance of hydrology for active layer processes is generally well acknowledged on a conceptual level, however the in general non-linear physical interdependencies between soil moisture, subsurface water and heat fluxes and active layer thaw progression are not fully understood. In this study, high resolution field data for the period 2000-2014 consisting of active layer and permafrost temperature, active layer soil moisture, and thaw depth progression from the UNISCALM research site in Adventdalen, Svalbard, is combined with a physically-based coupled cryotic and hydrogeological model to investigate active layer dynamics. The site is a loess-covered river terrace characterized by dry conditions with little to no summer infiltration and an unsaturated active layer. A range of soil moisture characteristic curves consistent with loess sediments is considered and their effects on ice and moisture redistribution, heat flux, energy storage through latent heat transfer, and active layer thickness is investigated and quantified based on hydro-climatic site conditions. Results show that soil moisture retention characteristics exhibit notable control on ice distribution and circulation within the active layer through cryosuction and are subject to seasonal variability and site-specific surface temperature variations. The retention characteristics also impact unfrozen water and ice content in the permafrost. Although these effects

  7. Finite stretching of an annular plate.

    Science.gov (United States)

    Biricikoglu, V.; Kalnins, A.

    1971-01-01

    The problem of the finite stretching of an annular plate which is bonded to a rigid inclusion at its inner edge is considered. The material is assumed to be isotropic and incompressible with a Mooney-type constitutive law. It is shown that the inclusion of the effect of the transverse normal strain leads to a rapid variation in thickness which is confined to a narrow edge zone. The explicit solutions to the boundary layer equations, which govern the behavior of the plate near the edges, are presented.

  8. Exchange bias training effect in Co/CoO heterostructures with variation of the ferromagnetic film thickness

    Science.gov (United States)

    Polisetty, Srinivas; Mukherjee, Tathagata; Sahoo, Sarbeswar; Binek, Christian

    2007-03-01

    The exchange bias (EB) training effect is studied in a Co/CoO heterostructure using low temperature longitudinal Kerr rotation. After field cooling the sample to below the N'eel temperature of CoO the EB training effect manifests itself by a decrease of the EB field upon cycling the Co film through consecutive hysteresis loops. We explore the temperature dependence of the training effect and its dependence on the Co-thickness, tCo. The latter is studied by locally probing the EB in a wedge Co/CoO system. The gradient of the Co film thickness allows to measure local tCo-dependences in a range of δtCo = 23.6nm varying over the substrate length of 8.5mm. The Co wedge is prepared by MBE taking advantage of the steep decrease of the Co flux when leaving the center of the Co beam. A wedge angle of 1.6x10-4;^ois revealed by local small angle X-ray reflectivity. We compare the measured tCo-dependence with our phenomenological theory predicting a tCo^2-increase of the leading fitting parameter. This behavior is clearly distinguishable from the 1/tCo -decrease of the equilibrium EB field.

  9. On the growth of the baleen plate of the Fin Whale and the Blue Whale

    NARCIS (Netherlands)

    Utrecht, van W.L.

    1965-01-01

    1. In Whales variations in the thickness of the baleen plates are supposed to give an insight into certain cyclical processes in the life of the animal. To a certain extent, by means of these variations, it is possible to reach conclusions about the age of the animal and/or about its recent period o

  10. On the growth of the baleen plate of the Fin Whale and the Blue Whale

    NARCIS (Netherlands)

    Utrecht, van W.L.

    1965-01-01

    1. In Whales variations in the thickness of the baleen plates are supposed to give an insight into certain cyclical processes in the life of the animal. To a certain extent, by means of these variations, it is possible to reach conclusions about the age of the animal and/or about its recent period

  11. The Notable Problem of T-R Probe in the Ultrasonic Inspection of Medium Thickness Plate%双晶探头在中厚板探伤应用中应注意的问题

    Institute of Scientific and Technical Information of China (English)

    司春杰

    2011-01-01

    The optimally focal distance of the selected probe was the half thickness of the medium thickness plate and the detection sensitivity should be adjusted by flat bottom which having double times focal distance when inspecting the plate by TR probe. Otherwise, paying more attention to the echo height of near surface defect, it seemed that the echo height did not reach the requirement, but it had met or exceeded the standard actually. It was also needed to notice the sound beam in order to avoid unnecessary losses by false method when the small flaw was identified as the big one artificially.%使用双晶探头检测中厚板时,选用探头的焦距以等于钢板厚度的一半为最佳,调整检测灵敏度最好以二倍焦距的大平底为基准,否则要注意近检测面缺陷信号,即使缺陷波高未达到判定条件,而实际缺陷有可能达到或超过控制要求。缺陷边界的测定要注意有效波束宽度问题,避免方法不当,人为地将小缺陷测定成了大缺陷,造成不必要的损失。

  12. Influence of copper plate thickness on thermo-mechanical behavior of slab mold%铜板厚度对板坯结晶器热力行为的影响

    Institute of Scientific and Technical Information of China (English)

    曹学欠; 陈杰; 林国海; 陈卫强

    2012-01-01

    基于某钢厂的铸机条件,建立了三维热弹塑性有限元模型,得到了不同厚度铜板的温度、变形量和等效应力应变的分布状态,指导了河北普阳钢铁有限公司结晶器的设计。结果表明:铜板越厚,热面温度越高,等效应力越小,变形量越大。铜板厚度每增加5mm,热面最高温度将相应增加30℃左右;热面最大等效应力将减dx7.5MPa2左右;热面最大变形量将相应增加0.05mm左右;较薄的铜板可减少浇铸过程中铜板的热变形。%In connection with the practical conditions of one caster in a specific plant a three-dimensional thermal elastic-plastic finite element model is established and distribu- tions of temperature, deformation rate and equivalent stress-strain for copper plates with different thickness are obtained. All those parameters are used to guide the design of mold in the Steelmaking Co. , Ltd. of Hebei Puyang Iron & Steel Corporation. Results show that the thicker the copper plate is, the higher the temperature will be at the hot surface, and the less the equivalent stress is, the larger the deformation rate will become. Every 5 mm increase in the thickness of the copper plate will inevitably lead to about 30℃ temperature increase in the highest hot surface and about 7. 5 MPa reduction of the maximum equivalent stress at the hot surface and about 0. 05 mm increase of the maximum deformation rate at the hot surface. Thinner copper plate is more helpful for reduction of the hot deformation of the copper plate in the process of casting.

  13. A Rigorous Derivation of the Equations for the Clamped Biot-Kirchhoff-Love Poroelastic plate

    CERN Document Server

    Marciniak-Czochra, Anna

    2012-01-01

    In this paper we investigate the limit behavior of the solution to quasi-static Biot's equations in thin poroelastic plates as the thickness tends to zero. We choose Terzaghi's time corresponding to the plate thickness and obtain the strong convergence of the three-dimensional solid displacement, fluid pressure and total poroelastic stress to the solution of the new class of plate equations. In the new equations the in-plane stretching is described by the 2D Navier's linear elasticity equations, with elastic moduli depending on Gassmann's and Biot's coefficients. The bending equation is coupled with the pressure equation and it contains the bending moment due to the variation in pore pressure across the plate thickness. The pressure equation is parabolic only in the vertical direction. As additional terms it contains the time derivative of the in-plane Laplacean of the vertical deflection of the plate and of the the elastic in-plane compression term.

  14. Analysis of Microstructures and Property of Welded Joint of EH36 Thick Steel Plate for Offshore Platform%海洋平台用EH36厚钢板焊接接头的组织性能分析

    Institute of Scientific and Technical Information of China (English)

    李敏

    2013-01-01

    In accordance with the requirements of EN 10225-2009 appendix E Standard, the EH36 thick steel plate with 100 mm thickness for offshore platforms was welded by submerge-arc welding technology with 50 kJ/cm high heat input. The microstructure and properties of the weld joint were analyzed. The results showed that either welded or heat treated after welding, the hardness HV10 of the weld joint of EH36 thick steel plate ≤ 280, tensile strength ≥ 510 MPa, the mean value of absorbed-in-fracture energy at-40℃≥50 J, the surface microstructure mainly are coarse lath bainite+a small amount of granular bainite and the core structure is fine ferrite+pearlite. This showed that the EH36 thick steel plates developed by Jinan Steel meet the welding needs of offshore platforms. The differences of the fusion line shape and heat transfer status between the surface and center of weld joint are main reasons to lead to surface HAZ grain coarser than those of center HAZ, so surface toughness is lower than that of center.%按照EN 10225-2009附录E标准要求,采用50 kJ/cm大热输入埋弧焊工艺焊接厚为100 mm海洋平台用EH36钢板,测试分析了焊态及焊后热处理态焊接接头的组织与性能。结果表明,无论焊态还是焊后热处理态,EH36厚钢板焊接接头的硬度HV10≤280,抗拉强度≥510 MPa,-40℃冲击功均值≥50 J,表面组织以粗大的板条状贝氏体+少量粒状贝氏体为主,心部组织以细小的铁素体+珠光体为主,表明济钢开发的EH36厚钢板满足海洋平台的焊接生产要求。焊接接头表面与心部熔合线形状及传热状态的差异,是导致表面HAZ晶粒比心部粗大、因而表面韧性低于心部的主要原因。

  15. Transient MHD Free Convective Flow of an Optically Thick Gray Gas Past a Moving Vertical Plate in the Presence of Thermal Radiation and Mass Diffusion

    Directory of Open Access Journals (Sweden)

    S.K Ghosh

    2015-01-01

    Full Text Available The purpose of present investigation is to analyse bouyancy-driven radiation-convection flow past a moving vertical plate with reference to an optically dense medium in the presence of mass concentration, using Rosseland approximation permeated by a magnetic field. The flow is considered to be gray in the presence of free convection, mass transfer and radiation. An exact solution of the governing equations is obtained by applying the Laplace transform method. Numerical results of velocity distributions, shear stress, temperature distribution and mass concentration are presented graphically to give physical insight into the flow pattern.

  16. Pressure-induced wall thickness variations in multi-layered wall of a pollen tube and Fourier decomposition of growth oscillations.

    Science.gov (United States)

    Pietruszka, Mariusz; Haduch-Sendecka, Aleksandra

    2015-04-01

    The augmented growth equation introduced by Ortega is solved for the apical portion of the pollen tube as an oscillating volume, which we approach in the framework of a two-fluid model in which the two fluids represent the constant pressure and the fluctuating features of the system. Based on routine Fourier analysis, we calculate the energy spectrum of the oscillating pollen tube, and discuss the resonant frequency problem of growth rate oscillations. We also outline a descriptive model for cell wall thickness fluctuations associated with small, yet regular variations (~ 0.01 MPa) observed in turgor pressure. We propose that pressure changes must lead to the sliding of wall layers, indirectly resulting in a wave of polarization of interlayer bonds. We conclude that pollen tube wall thickness may oscillate due to local variations in cell wall properties and relaxation processes. These oscillations become evident because of low amplitude/high frequency pressure fluctuations δP being superimposed on turgor pressure P. We also show that experimentally determined turgor pressure oscillates in a strict periodical manner. A solitary frequency f0 ≈ 0.066 Hz of these (~ 0.01 MPa in magnitude) oscillations for lily pollen tubes was established by the discrete Fourier transform and Lorentz fit.

  17. Longitudinal wave motion in width-constrained auxetic plates

    Science.gov (United States)

    Lim, Teik-Cheng

    2016-05-01

    This paper investigates the longitudinal wave velocity in auxetic plates in comparison to conventional ones, in which the plate is constrained from motion in the width direction. By taking into account the thickness change of the plate and its corresponding change in density, the developed wave velocity is casted not only as a function of Young’s modulus and density, but also in terms of Poisson’s ratio and longitudinal strain. Results show that density and thickness variations compensate for one another when the Poisson’s ratio is positive, but add up when the Poisson’s ratio is negative. Results also reveal that the classical model of longitudinal wave velocity for the plate is accurate when the Poisson’s ratio is about 1/3; at this Poisson’s ratio the influence from density and thickness variations cancel each other. Comparison between the current corrected model and the density-corrected Rayleigh-Lamb model reveals a number of consistent trends, while the discrepancies are elucidated. If the plate material possesses a negative Poisson’s ratio, the deviation of the actual wave velocity from the classical model becomes significant; auxeticity suppresses and enhances the wave velocity in compressive and tensile impacts, respectively. Hence the use of the corrected model is proposed when predicting longitudinal waves in width-constrained auxetic plates, and auxetic materials can be harnessed for effectively controlling wave velocities in thin-walled structures.

  18. 插头镀金线镀层厚度计算模型研究%Study on calculational model for the electrodeposited coatings thickness of nickel and gold about plug gold plating line

    Institute of Scientific and Technical Information of China (English)

    高来华; 陈海燕

    2014-01-01

    电镀镍金镀层厚度是PCB产品可靠性的关键指标,文章从插头镀金线实际生产需求出发,运用法拉第定律和多元函数进行数学推导,得出一个普遍适用于插头镀金线镀层厚度理论计算模型。在理论计算模型的基础上进行多次试验分别得出电镀镍和电镀金的电流效率,并对实际镀层厚度计算模型的有效性进行重复试验验证。试验结果表明,我们可以得出一个合理的镀层厚度计算模型以指导插头镀金线实际生产。%The electrodeposited coatings thickness of Nickel and Gold is the crucial quality index for PCB manufacture reliability. The paper makes use of Faraday Law and function of many variables to deduce an applicable theoretical calculational model for the electrodeposited coatings thickness of Nickel and Gold about Plug Gold plating line. We carried out so many experiments based on the theoretical calculational model that the current efifciencies about electroplating Nickel and Gold are worked out. We veriifed the effectiveness of the actual calculational model by repeated experiments. The results shows that we can get a logical calculational model to the electrodeposited coatings thickness for Plug Gold plating line in practice.

  19. An improved model for predicting performance of finned tube heat exchanger under frosting condition, with frost thickness variation along fin

    Energy Technology Data Exchange (ETDEWEB)

    Tso, C.P. [Multimedia University, Jalan Ayer Keroh Lama, Melaka (Malaysia). Faculty of Engineering and Technology; Cheng, Y.C.; Lai, A.C.K. [Nanyang Technological University, Singapore (Singapore). School of Mechanical and Aerospace Engineering

    2006-01-15

    Frost accumulation on a heat exchanger, a direct result of combined heat and mass transfer between the moist air flowing across a cold surface, causes heat transfer performance degradation due to the insulating effect of frost layer and the coil blockage as the frost grows. The complex geometry of finned tube heat exchangers leads to uneven wall and air temperature distribution inside the coil, and causes variations of frost growth rate and densification along the coil. In this study, a general distributed model with frost formation was developed. The equations for finned tube heat exchanger were derived in non-steady-state manner and quasi-steady state in the frost model. In order to make the model more realistic, the variation of frost along fin due to uneven temperature distribution was included. The presented model is able to predict the dynamic behavior of an air cooler both under non-frost and frost condition. Comparisons were made based on the frost mass accumulation, pressure drop across coil and energy transfer coefficient, and results were found to agree well with reported experimental results. (author)

  20. Variations in the buccal-lingual alveolar bone thickness of impacted mandibular third molar: our classification and treatment perspectives.

    Science.gov (United States)

    Ge, Jing; Zheng, Jia-Wei; Yang, Chi; Qian, Wen-Tao

    2016-01-13

    Selecting either buccal or lingual approach for the mandibular third molar surgical extraction has been an intense debate for years. The aim of this observational retrospective study was to classify the molar based on the proximity to the external cortical bone, and analyze the position of inferior alveolar canal (IAC) of each type. Cone-beam CT (CBCT) data of 110 deeply impacted mandibular third molars from 91 consecutive patients were analyzed. A new classification based on the mean deduction value (MD) of buccal-lingual alveolar bone thickness was proposed: MD≥1 mm was classified as buccal position, 1 mm>MD>-1 mm was classified as central position, MD≤-1 mm was classified as lingual position. The study samples were distributed as: buccal position (1.8%) in 2 subjects, central position (10.9%) in 12 and lingual position (87.3%) in 96. Ninety-six molars (87.3%) contacted the IAC. The buccal and inferior IAC course were the most common types in impacted third molar, especially in lingually positioned ones. Our study suggested that amongst deeply impacted mandibular third molars, lingual position occupies the largest proportion, followed by the central, and then the buccal type.

  1. Structural variation of solid core and thickness of porous shell of 1.7 μm core-shell silica particles on chromatographic performance: narrow bore columns.

    Science.gov (United States)

    Omamogho, Jesse O; Hanrahan, John P; Tobin, Joe; Glennon, Jeremy D

    2011-04-15

    Chromatographic and mass transfer kinetic properties of three narrow bore columns (2.1×50 mm) packed with new core-shell 1.7 μm EIROSHELL™-C(18) (EiS-C(18)) particles have been studied. The particles in each column varied in the solid-core to shell particle size ratio (ρ), of 0.59, 0.71 and 0.82, with a porous silica shell thickness of 350, 250 and 150 nm respectively. Scanning and transmission electron microscopy (SEM and TEM), Coulter counter analysis, gas pycnometry, nitrogen sorption analysis and inverse size exclusion chromatography (ISEC) elucidated the physical properties of these materials. The porosity measurement of the packed HILIC and C(18) modified phases provided the means to estimate the phase ratios of the three different shell columns (EiS-150-C(18), EiS-250-C(18) and EiS-350-C(18)). The dependence of the chromatographic performance to the volume fraction of the porous shell was observed for all three columns. The naphtho[2,3-a]pyrene retention factor of k'∼10 on the three EiS-C(18s) employed to obtain the height equivalents to theoretical plates (HETPs) data were achieved by varying the mobile phase compositions and applying the Wilke and Chang relationship to obtain a parallel reduced linear velocity. The Knox fit model gave the coefficient of the reduce HETPs for the three EiS-C(18s). The reduced plate height minimum h(min)=1.9 was achieved for the EiS-150-C(18) column, and generated an efficiency of over 350,000 N/m and h(min)=2.5 equivalent to an efficiency of 200,000 N/m for the EiS-350-C(18) column. The efficiency loss of the EiS-C18 column emanating from the system extra-column volume was discussed with respect to the porous shell thickness.

  2. Design of Quenching Automatic Control System for Thick Plate%宽厚板淬火自动化控制系统的设计

    Institute of Scientific and Technical Information of China (English)

    张元华

    2013-01-01

    The control techanics of the quenching process of the thick metal sheet produces main effect in stability production, energy-saving and increases labour productivity. But the control system have hysteresis, uncertainty, and random perturbation, these performances increase the difficulty in control, so, how to solve the problems of the control system, achieve effectively control has a great realistic significance for increases application area of thick metal sheet in the country.%厚板控冷淬火过程控制技术在稳定生产、节能降耗、提高生产工艺指标和提高劳动生产率等方面,均能发挥着重要的作用,但是它控制系统本身所存在的滞后性、不确定性和随机扰动性,加大了对它的控制难度,因此,如何克服控制系统本身所存在的缺陷,实现有效的控制,对于提高国内厚板行业的应用水平具有重大的现实意义.

  3. Analytical model for an asymmetric double-gate MOSFET with gate-oxide thickness and flat-band voltage variations in the subthreshold region

    Science.gov (United States)

    Shin, Yong Hyeon; Yun, Ilgu

    2016-06-01

    This paper proposes an analytical model for an asymmetric double-gate metal-oxide-semiconductor field-effect transistor (DG MOSFET) with varying gate-oxide thickness (tox) and flat-band voltage (Vfb) in the subthreshold region. Since such variations cannot be completely avoided, the modeling of their behaviors is essential. The analytical model is developed by solving a 2D Poisson equation with a varying channel doping concentration (NA). To solve the 2D Poisson equation of the asymmetric DG MOSFET, a perturbation method is used to separate the solution of the channel potential into basic and perturbed terms. Since the basic terms can be regarded as the equations derived from a general symmetric doped DG MOSFET, the conventional analytical model is adopted. In addition, a solution related to the perturbed terms for the asymmetric structures is obtained using Fourier series. Based on the obtained channel potential, the electrical characteristics of the drive current (IDS) are expressed in the analytical model. The prediction of the electrical characteristics by the analytical model shows excellent agreement when compared with commercially available 2D numerical device simulation results with respect to not only tox and Vfb variations but also channel length and NA variations.

  4. Inverse problem of pulsed eddy current field of ferromagnetic plates

    Science.gov (United States)

    Chen, Xing-Le; Lei, Yin-Zhao

    2015-03-01

    To determine the wall thickness, conductivity and permeability of a ferromagnetic plate, an inverse problem is established with measured values and calculated values of time-domain induced voltage in pulsed eddy current testing on the plate. From time-domain analytical expressions of the partial derivatives of induced voltage with respect to parameters, it is deduced that the partial derivatives are approximately linearly dependent. Then the constraints of these parameters are obtained by solving a partial linear differential equation. It is indicated that only the product of conductivity and wall thickness, and the product of relative permeability and wall thickness can be determined accurately through the inverse problem with time-domain induced voltage. In the practical testing, supposing the conductivity of the ferromagnetic plate under test is a fixed value, and then the relative variation of wall thickness between two testing points can be calculated via the ratio of the corresponding inversion results of the product of conductivity and wall thickness. Finally, this method for wall thickness measurement is verified by the experiment results of a carbon steel plate. Project supported by the National Defense Basic Technology Research Program of China (Grant No. Z132013T001).

  5. Using H/V Spectral Ratio Analysis to Map Sediment Thickness and to Explain Macroseismic Intensity Variation of a Low-Magnitude Seismic Swarm in Central Belgium

    Science.gov (United States)

    Van Noten, K.; Lecocq, T.; Camelbeeck, T.

    2013-12-01

    Between 2008 and 2010, the Royal Observatory of Belgium received numerous ';Did You Feel It'-reports related to a 2-year lasting earthquake swarm at Court-Saint-Etienne, a small town in a hilly area 20 km SE of Brussels, Belgium. These small-magnitude events (-0.7 ≤ ML ≤ 3.2, n = c. 300 events) were recorded both by the permanent seismometer network in Belgium and by a locally installed temporary seismic network deployed in the epicentral area. Relocation of the hypocenters revealed that the seismic swarm can be related to the reactivation of a NW-SE strike-slip fault at 3 to 6 km depth in the basement rocks of the Lower Palaeozoic London-Brabant Massif. This sequence caused a lot of emotion in the region because more than 60 events were felt by the local population. Given the small magnitudes of the seismic swarm, most events were more often heard than felt by the respondents, which is indicative of a local high-frequency earthquake source. At places where the bedrock is at the surface or where it is covered by thin alluvial sediments ( 30 m). In those river valleys that have a considerable alluvial sedimentary cover, macroseismic intensities are again lower. To explain this variation in macroseismic intensity we present a macroseismic analysis of all DYFI-reports related to the 2008-2010 seismic swarm and a pervasive H/V spectral ratio (HVSR) analysis of ambient noise measurements to model the thickness of sediments covering the London-Brabant Massif. The HVSR method is a very powerful tool to map the basement morphology, particularly in regions of unknown subsurface structure. By calculating the soil's fundamental frequency above boreholes, we calibrated the power-law relationship between the fundamental frequency, shear wave velocity and the thickness of sediments. This relationship is useful for places where the sediment thickness is unknown and where the fundamental frequency can be calculated by H/V spectral ratio analysis of ambient noise. In a

  6. Obliquity along plate boundaries

    Science.gov (United States)

    Philippon, Mélody; Corti, Giacomo

    2016-12-01

    Most of the plate boundaries are activated obliquely with respect to the direction of far field stresses, as roughly only 8% of the plate boundaries total length shows a very low obliquity (ranging from 0 to 10°, sub-orthogonal to the plate displacement). The obliquity along plate boundaries is controlled by (i) lateral rheological variations within the lithosphere and (ii) consistency with the global plate circuit. Indeed, plate tectonics and magmatism drive rheological changes within the lithosphere and consequently influence strain localization. Geodynamical evolution controls large-scale mantle convection and plate formation, consumption, and re-organization, thus triggering plate kinematics variations, and the adjustment and re-orientation of far field stresses. These geological processes may thus result in plate boundaries that are not perpendicular but oblique to the direction of far field stresses. This paper reviews the global patterns of obliquity along plate boundaries. Using GPlate, we provide a statistical analysis of present-day obliquity along plate boundaries. Within this framework, by comparing natural examples and geological models, we discuss deformation patterns and kinematics recorded along oblique plate boundaries.

  7. Applying Infrared Thermography as a Quality-Control Tool for the Rapid Detection of Proton-Electrolyte-Membrane-Fuel-Cell Catalyst-Layer-Thickness Variations

    Energy Technology Data Exchange (ETDEWEB)

    Aieta, N. V.; Das, P. K.; Perdue, A.; Bender, G.; Herring, A. M.; Weber, A. Z.; Ulsh, M. J.

    2012-08-01

    As fuel cells become more prominent, new manufacturing and production methods are needed to enable increased volumes with high quality. One necessary component of this industrial growth will be the accurate measurement of the variability of a wide range of material properties during the manufacturing process. In this study, a method to detect defects in fuel cell catalyst layers is investigated through experiment and mathematical simulation. The method uses infrared thermography and direct-current electronic-excitation methods to detect variations in platinum-containing catalyst-layer thickness with high spatial and temporal resolution. Data analysis, operating-condition impacts, and detection limits are explored, showing the measurement of defects on the millimeter length scale. Overall, the experimental and modeling results demonstrate great potential of this technique as a nondestructive method to measure defects that is amenable to use on roll-to-roll manufacturing lines.

  8. Hard photon yields from (70-240) GeV electrons incident near axial directions on Si, Ge and W single crystals with a large thickness variation

    Science.gov (United States)

    Medenwaldt, R.; Møller, S. P.; Tang-Petersen, S.; Uggerhøj, E.; Elsener, K.; Hage-Ali, M.; Siffert, P.; Stoquert, J.; Sona, P.; Maier, K.

    1990-06-01

    The dramatic peak found in photon spectra from 150 GeV channelled electrons has for the first time been investigated for 70, 150, and 240 GeV electrons incident on crystals with thickness from 100μ (Si). Very pronounced variations for the high energy part of the photon spectra are found. In Si the photon peak is not found for lower energies and thin crystals. For well-aligned electrons in Si the yield is more than 160 times the Bethe-Heitler one. In general the peak in the photon spectra disaapears for incident angles larger than half the critical angle for channeling. Dramatic radiative energy losses are found along axial directions - in 0.6 mm Ge a 150 GeV electron loses more than 60% of its total energy.

  9. Hard photon yields from (70-240) GeV electrons incident near axial directions on Si, Ge and W single crystals with a large thickness variation

    Energy Technology Data Exchange (ETDEWEB)

    Medenwaldt, R.; Moeller, S.P.; Tang-Petersen, S.; Uggerhoej, E. (Aarhus Univ. (Denmark). Inst. of Physics); Elsener, K. (European Organization for Nuclear Research, Geneva (Switzerland)); Hage-Ali, M.; Siffert, P.; Stoquert, J. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires); Sona, P. (Florence Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Florence (Italy)); Maier, K. (Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany, F.R.))

    1990-06-14

    The dramatic peak found in photon spectra from 150 GeV channelled electrons has for the first time been investigated for 70, 150, and 240 GeV electrons incident on crystals with thicknesses from 100 {mu}m to 1400 {mu}m (Si). Very pronounced variations for the high energy part of the photon spectra are found. In Si the photon peak is not found for lower energies and thin crystals. For well-aligned electrons in Si the yield is more than 160 times the Bethe-Heitler one. In general the peak in the photon spectra disappears for incident angles larger than half the critical angle for channelling. Dramatic radiative energy losses are found along axial directions - in 0.6 mm <110> Ge a 150 GeV electron loses more than 60% of its total energy. (orig.).

  10. High Power Laser Beam Welding of Thick-walled Ferromagnetic Steels with Electromagnetic Weld Pool Support

    Science.gov (United States)

    Fritzsche, André; Avilov, Vjaceslav; Gumenyuk, Andrey; Hilgenberg, Kai; Rethmeier, Michael

    The development of modern high power laser systems allows single pass welding of thick-walled components with minimal distortion. Besides the high demands on the joint preparation, the hydrostatic pressure in the melt pool increases with higher plate thicknesses. Reaching or exceeding the Laplace pressure, drop-out or melt sagging are caused. A contactless electromagnetic weld support system was used for laser beam welding of thick ferromagnetic steel plates compensating these effects. An oscillating magnetic field induces eddy currents in the weld pool which generate Lorentz forces counteracting the gravity forces. Hysteresis effects of ferromagnetic steels are considered as well as the loss of magnetization in zones exceeding the Curie temperature. These phenomena reduce the effective Lorentz forces within the weld pool. The successful compensation of the hydrostatic pressure was demonstrated on up to 20 mm thick plates of duplex and mild steel by a variation of the electromagnetic power level and the oscillation frequency.

  11. Simulation of bending stress variation in long buried thick-walled pipes under the earth’s movement using combined linear dynamics and beam theories

    Directory of Open Access Journals (Sweden)

    Salau Tajudeen A.O.

    2014-01-01

    Full Text Available This study reported a simulation approach to the understanding of the interactions between a buried pipe and the soil system by computing the bending stress variation of harmonically-excited buried pipes. The established principles of linear dynamics theory and simple beam theory were utilised in the analysis of the problem of buried pipe bending stress accumulation and its dynamics. With regards to the parameters that influence the bending stress variations, the most important are the isolation factor, uniform external load, and the corresponding limiting conditions. The simulated mathematical expressions, containing static and dynamic parameters of the buried pipe and earth, were coded in Fortran programming language and applied in the simulation experiment. The results obtained showed that harmonically-excited buried thick-walled pipe became stable and effective when the ratio of the natural frequency of vibration to the forced frequency is greater than 2.0, whenever the damped factor is used as the control parameter for the maximum bending stress. The mirror image of the stress variation produces variation in the location of the maximum bending stress in quantitative terms. The acceptable pipe materials for the simulated cases must have yield strength in bending greater than or equal to 13.95 MPa. The results obtained in this work fill a gap in the literature and will be useful to pipeline engineers and designers, as well as to environmental scientists in initialising and controlling environmental issues and policy formulation concerning the influence of buried pipe on the soil and water in the environment.

  12. Porous Flanging Process Analysis and Dies Design on the Moderate Thickness Plate%中厚板多孔翻边工艺分析及模具设计

    Institute of Scientific and Technical Information of China (English)

    陈卫; 王勤家

    2012-01-01

    以某出口车型外观件封板为例,结合现场生产环境,改进工艺方法,设计了中厚板大尺寸多内孔整体翻边模,实现封板的整体内孔翻边,提高工件局部强度,解决了焊接带来的变形及平面度超差问题,提高生产效率,满足了制件的批量生产需求。%Set the shrouding of the appearance plate on one of the exported wagons as an example, incorporated with the onsite production environment, with improved processing methods to design the jumbo size of entire flanging dies with inner porous for the moderate thickness plate, aims to achieve the entire inner porous flanging of the shrouding. As a result, the local strength of the working pieces has been enhanced and solved the deformation and over proof of the flatness by welding, then the production rate is raised, meet the mass production requirements.

  13. Variation.

    Science.gov (United States)

    Hamilton City Board of Education (Ontario).

    Suggestions for studying the topic of variation of individuals and objects (balls) to help develop elementary school students' measurement, comparison, classification, evaluation, and data collection and recording skills are made. General suggestions of variables that can be investigated are made for the study of human variation. Twelve specific…

  14. The uncertainty of estimating the thickness of soft sediments with the HVSR method: A computational point of view on weak lateral variations

    Science.gov (United States)

    Bignardi, Samuel

    2017-10-01

    The use of the ratio of microtremor spectra, as computed by the Nakamura's technique, was recently proved successful for the evaluating the thickness of sedimentary covers laying over both shallow and deep rocky bedrocks thus enabling bedrock mapping. The experimental success of such application and its experimental uncertainties are today reported in many publications. To map bedrock, two approaches exist. The first is to assume a constant shear wave velocity profile of the sediments. The second, and most preferable, is Ibs-von Seht and Wohlenberg's, based on correlating Nakamura's curves main peak and wells information. In the latter approach, the main sources of uncertainty addressed by authors, despite the lack of formal proof, comprise local deviations of the subsurface from the assumed model. I first discuss the reliability of the simplified constant velocity approach showing its limitations. As a second task, I evaluate the uncertainty of the Ibs-von Seht and Wohlenberg's approach with focus on local subsurface variations. Since the experimental basis is well established, I entirely focus my investigation on numerical simulations to evaluate to what extent local subsurface deviations from the assumed model may affect the outcome of a bedrock mapping survey. Further, the present investigation strategy suggests that modeling and inversion, through the investigation of the parameters space around the reference model, may reveal a very convenient tool when lateral variations are suspected to exist or when the number of available wells is not sufficient to obtain an accurate frequency-depth regression.

  15. Impacts of multi-point incremental forming process parameters on plate thickness thinning%工艺参数对多点复合渐进成形厚度减薄的影响

    Institute of Scientific and Technical Information of China (English)

    蔡改贫; 周小磊; 熊洋; 蒙鹏宇

    2015-01-01

    To better improve the forming quality and prevent rupture defects in multi⁃point composite incremental forming(MPCIF) , through the establishment of three⁃dimensional finite element model of forming pyramid machine parts with different process parameters is simulated and analyzed, and discussed the thickness distribution and the change in stamping forming process and the influence of different process parameters on the thickness reduction ratio. The simulation results show that the maximum thickness reduction ratio occurs at the diagonal of the parts, plate′s thickness thinning can be more serious with the tools size or initial thickness is smaller and the forming angle or the feed rate is bigger, plate becomes more easy to crack at these situations. The test of MPCIF shows that the simulation results fit well with the test results.%为提高成形质量、预防破裂等缺陷,在金属板材多点复合渐进成形的基础上,通过建立三维有限元模型,对不同工艺参数成形方锥台制件进行了数值模拟和分析,探讨了制件成形过程中厚度分布和变化情况及不同工艺参数对厚度减薄率的影响。数值模拟结果表明,制件成形区对角线上的厚度减薄相比中线上的更严重,工具头直径和板材初始厚度越小、成形角和进给量越大,制件所能达到的最大厚度减薄率越大,制件越易破裂。多点复合渐进成形试验表明,数值模拟结果与实验相吻合。

  16. Short-term variation of central corneal thickness and axial anterior chamber depth of healthy eyes using Scheimpflug photography via the Oculus Pentacam*

    Directory of Open Access Journals (Sweden)

    S. D. Mathebula

    2009-12-01

    Full Text Available The purpose of this study was to investigate short-term variation and intra-subject repeatabil-ity of  human central corneal thickness (CCT and axial anterior chamber depth (AACD measure-ments obtained using the Oculus Pentacam. Forty consecutive images of the right eye of the anteriorsegment of 10 young and healthy individuals were measured with the Pentacam. Measurements of CCT and AACD were ob-tained from these images and means, standard deviations,variances and repeatability of the measurements were investigated. Both parameters (CCTand AACD showed small variation with good orexcellent repeatability for all eyes. The inter-subject or overall means and standard deviations for CCT and AACD of the 10 right eyes were 0.555 ±0.05 millimeters (or 555 ± 50 microns and 3.206± 0.04 millimeters, respectively. The individual or intra-subject averages for samples of CCT and AACD measurements are also provided in this paper. Univariate normality of the data was explored with Kolmogorov-Smirnov, Lilliefors and ShapiroWilks tests and we found that generally the data was normally distributed although there were some exceptions. Based on the results of this study, the Oculus Pentacam appears to provide repeatable and reliable measures for both CCT and AACD in young,normal eyes. Further research is, however, needed to determine short-term variation and repeatability of CCT and AACD with the Pentacam in more com-plicated eyes with, say, corneal scarring or ectasia or where refractive surgery may be an issue.

  17. Relaxation, contraction, and polar wander: A study of the evolution of crustal and lithospheric thickness variations on the Moon, Mars, Mercury, and Ganymede

    Science.gov (United States)

    Mohit, Pundit Surdasji

    The majority of the surfaces of the Moon, Mars, Mercury, and Ganymede were shaped during the first 500-1000 Myr of the Solar System. As a result, they provide great insight into the processes that must have occurred on most, if not all, terrestrial planets and moons during that time period. In this study, a semi-analytic, self-gravitating, viscoelastic model of planetary deformation is developed and applied to the evolution of variations in their mechanical properties. First, the plausibility of viscous relaxation of large multi-ring lunar basins is investigated. This is found to be likely to have occurred during the first few hundred million years of lunar history, which places constraints on the timing and mechanism of crystallization of the lunar magma ocean. Second, the physical parameters of the largest martian basins are analyzed and found to be consistent with the occurrence of viscous relaxation throughout the period of heavy bombardment. The viscoelastic model is then employed to place constraints on the thermal state of early Mars. Third, the model is expanded to include lateral variations in viscosity and applied to the early contraction of Mercury. The results confirm the hypothesis that the amount of radial contraction has previously been underestimated. In addition to its expression through thrust faults, some fraction of the compressive stress was possibly taken up by long-wavelength folding of the mercurian lithosphere. Finally, an explanation of the anomalous cratering asymmetry between the leading and trailing hemispheres of Ganymede is proposed. Rotational dynamics calculations show that the thickness variations induced by the pole-to-equator temperature contrast was likely sufficient to make the axis of rotation unstable and cause the poles to exchange positions with the leading and trailing points.

  18. Effect of Small Variation in the Composition of Plates and Weld Filler Wires on the General Corrosion Rate of Ni-Cr-Mo Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fix, D V; Estill, J C; Rebak, R B

    2005-02-05

    The ASTM standard B 575 provides the requirements for the chemical composition of Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloys such as Alloy 22 (N06022) and Alloy 686 (N06686). The compositions of each element are given in a range. For example, the content of Mo is specified from 12.5 to 14.5 weight percent for Alloy 22 and from 15.0 to 17.0 weight percent for Alloy 686. It was important to determine how the corrosion rate of welded plates of Alloy 22 using Alloy 686 weld filler metal would change if heats of these alloys were prepared using several variations in the composition of the elements even though still in the range specified in B 575. All the material used in this report were especially prepared at Allegheny Ludlum Co. Seven heats of plate were welded with seven heats of wire. Immersion corrosion tests were conducted in a boiling solution of sulfuric acid plus ferric sulfate (ASTM G 28 A) using both as-welded (ASW) coupons and solution heat-treated (SHT) coupons. Results show that the corrosion rate was not affected by the chemistry of the materials within the range of the standards.

  19. NONLINEAR NATURAL FREQUENCY OF SHALLOW CONICAL SHELLS WITH VARIABLE THICKNESS

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-zhi; HAN Ming-jun; ZHAO Yong-gang; YEH Kai-yuan

    2005-01-01

    The nonlinear dynamical variation equation and compatible equation of the shallow conical shell with variable thickness are obtained by the theory of nonlinear dynamical variation equation and compatible equation of the circular thin plate with variable thickness. Assuming the thin film tension is composed of two items. The compatible equation is transformed into two independent equations. Selecting the maximum amplitude in the center of the shallow conical shells with variable thickness as the perturbation parameter,the variation equation and the differential equation are transformed into linear expression by theory of perturbation variation method. The nonlinear natural frequency of shallow conical shells with circular bottom and variable thickness under the fixed boundary conditions is solved. In the first approximate equation, the linear natural frequency of shallow conical shells with variable thickness is obtained. In the third approximate equation, the nonlinear uatural frequency of it is obtained. The figures of the characteristic curves of the natural frequency varying with stationary loads, large amplitude, and variable thickness coefficient are plotted. A valuable reference is given for dynamic engineering.

  20. Spatial and temporal variations in creep rate along the El Pilar fault at the Caribbean-South American plate boundary (Venezuela), from InSAR

    Science.gov (United States)

    Pousse Beltran, Léa.; Pathier, Erwan; Jouanne, François; Vassallo, Riccardo; Reinoza, Carlos; Audemard, Franck; Doin, Marie Pierre; Volat, Matthieu

    2016-11-01

    In eastern Venezuela, the Caribbean-South American plate boundary follows the El Pilar fault system. Previous studies based on three GPS campaigns (2003-2005-2013) demonstrated that the El Pilar fault accommodates the whole relative displacement between the two tectonic plates (20 mm/yr) and proposed that 50-60% of the slip is aseismic. In order to quantify the possible variations of the aseismic creep in time and space, we conducted an interferometric synthetic aperture radar (InSAR) time series analysis, using the (NSBAS) New Small BAseline Subset method, on 18 images from the Advanced Land Observing Satellite (ALOS-1) satellite spanning the 2007-2011 period. During this 3.5 year period, InSAR observations show that aseismic slip decreases eastward along the fault: the creep rate of the western segment reaches 25.3 ± 9.4 mm/yr on average, compared to 13.4 ± 6.9 mm/yr on average for the eastern segment. This is interpreted, through slip distribution models, as being related to coupled and uncoupled areas between the surface and 20 km in depth. InSAR observations also show significant temporal creep rate variations (accelerations) during the considered time span along the western segment. The transient behavior of the creep is not consistent with typical postseismic afterslip following the 1997 Ms 6.8 earthquake. The creep is thus interpreted as persistent aseismic slip during an interseismic period, which has a pulse- or transient-like behavior.

  1. Casimir force between metal plate and dielectric plate

    Institute of Scientific and Technical Information of China (English)

    刘中柱; 邵成刚; 罗俊

    1999-01-01

    The Casimir effect between metal plate and dielectric plate is discussed with 1+1-dimensional potential model without using cut-off method. Calculation shows that the Casimir force between metal plate and dielectric plate is determined not only by the potential V0, the dielectric thickness and the distance α between the metal plate and dielectric plate, but also by the dimension of the vessel. When α is far less than the dimension of the vessel, the Casimir force Fc∝α(-1); conversely Fc∝α-2. This result is significant for Casimir force experiment.

  2. Evaluation of plate type fuel elements by eddy current test method; Avaliacao de combustiveis nucleares tipo placa pelo metodo de correntes parasitas

    Energy Technology Data Exchange (ETDEWEB)

    Frade, Rangel Teixeira

    2015-07-01

    Plate type fuel elements are used in MTR research nuclear reactors. The fuel plates are manufactured by assembling a briquette containing the fissile material inserted in a frame, with metal plates in both sides of the set, to act as a cladding. This set is rolled under controlled conditions in order to obtain the fuel plate. In Brazil, this type of fuel is manufactured by IPEN and used in the IEA-R1 reactor. After fabrication of three batches of fuel plates, 24 plates, one of them is taken, in order to verify the thickness of the cladding. For this purpose, the plate is sectioned and the thickness measurements are carried out by using optical microscopy. This procedure implies in damage of the plate, with the consequent cost. Besides, the process of sample preparation for optical microscopy analysis is time consuming, it is necessary an infrastructure for handling radioactive materials and there is a generation of radioactive residues during the process. The objective of this study was verify the applicability of eddy current test method for nondestructive measurement of cladding thickness in plate type nuclear fuels, enabling the inspection of all manufactured fuel plates. For this purpose, reference standards, representative of the cladding of the fuel plates, were manufactured using thermomechanical processing conditions similar to those used for plates manufacturing. Due to no availability of fuel plates for performing the experiments, the presence of the plate’s core was simulated using materials with different electrical conductivities, fixed to the thickness reference standards. Probes of eddy current testing were designed and manufactured. They showed high sensitivity to thickness variations, being able to separate small thickness changes. The sensitivity was higher in tests performed on the reference standards and samples without the presence of the materials simulating the core. For examination of the cladding with influence of materials simulating the

  3. Eddy current thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, Gary J.; Sinclair, Frank; Soskov, Alexander; Buff, James S.

    2015-06-16

    A sheet of a material is disposed in a melt of the material. The sheet is formed using a cooling plate in one instance. An exciting coil and sensing coil are positioned downstream of the cooling plate. The exciting coil and sensing coil use eddy currents to determine a thickness of the solid sheet on top of the melt.

  4. Multimodal and omnidirectional beam splitters for Lamb modes in elastic plates

    Directory of Open Access Journals (Sweden)

    Yabin Jin

    2016-12-01

    Full Text Available Omnidirectional beam splitters for the simultaneous control of the three fundamental Lamb modes in an elastic plate are designed and numerically studied. Beam splitters consist in radially symmetric and inhomogeneous lenses designed to redirect the incoming energy towards a given angle. In this work, these devices are designed by means of graded phononic crystals combined with thickness variations of the plate. Numerical simulations are presented to show the performance of the designed devices.

  5. Multimodal and omnidirectional beam splitters for Lamb modes in elastic plates

    Science.gov (United States)

    Jin, Yabin; Torrent, Daniel; Pennec, Yan; Lévêque, Gaëtan; Pan, Yongdong; Djafari-Rouhani, Bahram

    2016-12-01

    Omnidirectional beam splitters for the simultaneous control of the three fundamental Lamb modes in an elastic plate are designed and numerically studied. Beam splitters consist in radially symmetric and inhomogeneous lenses designed to redirect the incoming energy towards a given angle. In this work, these devices are designed by means of graded phononic crystals combined with thickness variations of the plate. Numerical simulations are presented to show the performance of the designed devices.

  6. Multi-Mode Electromagnetic Ultrasonic Lamb Wave Tomography Imaging for Variable-Depth Defects in Metal Plates

    Directory of Open Access Journals (Sweden)

    Songling Huang

    2016-05-01

    Full Text Available This paper proposes a new cross-hole tomography imaging (CTI method for variable-depth defects in metal plates based on multi-mode electromagnetic ultrasonic Lamb waves (LWs. The dispersion characteristics determine that different modes of LWs are sensitive to different thicknesses of metal plates. In this work, the sensitivities to thickness variation of A0- and S0-mode LWs are theoretically studied. The principles and procedures for the cooperation of A0- and S0-mode LW CTI are proposed. Moreover, the experimental LW imaging system on an aluminum plate with a variable-depth defect is set up, based on A0- and S0-mode EMAT (electromagnetic acoustic transducer arrays. For comparison, the traditional single-mode LW CTI method is used in the same experimental platform. The imaging results show that the computed thickness distribution by the proposed multi-mode method more accurately reflects the actual thickness variation of the defect, while neither the S0 nor the A0 single-mode method was able to distinguish thickness variation in the defect region. Moreover, the quantification of the defect’s thickness variation is more accurate with the multi-mode method. Therefore, theoretical and practical results prove that the variable-depth defect in metal plates can be successfully quantified and visualized by the proposed multi-mode electromagnetic ultrasonic LW CTI method.

  7. Multi-Mode Electromagnetic Ultrasonic Lamb Wave Tomography Imaging for Variable-Depth Defects in Metal Plates.

    Science.gov (United States)

    Huang, Songling; Zhang, Yu; Wang, Shen; Zhao, Wei

    2016-05-02

    This paper proposes a new cross-hole tomography imaging (CTI) method for variable-depth defects in metal plates based on multi-mode electromagnetic ultrasonic Lamb waves (LWs). The dispersion characteristics determine that different modes of LWs are sensitive to different thicknesses of metal plates. In this work, the sensitivities to thickness variation of A0- and S0-mode LWs are theoretically studied. The principles and procedures for the cooperation of A0- and S0-mode LW CTI are proposed. Moreover, the experimental LW imaging system on an aluminum plate with a variable-depth defect is set up, based on A0- and S0-mode EMAT (electromagnetic acoustic transducer) arrays. For comparison, the traditional single-mode LW CTI method is used in the same experimental platform. The imaging results show that the computed thickness distribution by the proposed multi-mode method more accurately reflects the actual thickness variation of the defect, while neither the S0 nor the A0 single-mode method was able to distinguish thickness variation in the defect region. Moreover, the quantification of the defect's thickness variation is more accurate with the multi-mode method. Therefore, theoretical and practical results prove that the variable-depth defect in metal plates can be successfully quantified and visualized by the proposed multi-mode electromagnetic ultrasonic LW CTI method.

  8. 高层建筑用 Q460GJD-Z35厚钢板研发实践%Development practice of Q460GJD-Z35 thick steel plates for high-rise building

    Institute of Scientific and Technical Information of China (English)

    杨东; 李忠波; 唐郑磊; 刘庆波; 庞百鸣

    2015-01-01

    The development process of 60-80 mm thickness Q460GJD-Z35 steel plate for high-rise building in Nan-yang Hanye Special Steel Co.,Ltd.,by 100t converter-LF+VD refining-pouring-3800mm mill TMCP rolling was introduced.Based on the rational design of the chemical compositions,severe smelting and casting as well as the reasonable billet heating and TMCP rolling process control,the 60-80 mm thickness Q460GJD-Z35 steel plate un-der TMCP delivery state was successfully developed.With the micro-alloying composition design,through the TM-CP process,the excellent mechanical performance indexes for the steel under controlled rolling condition was ob-tained by making full use of fine grain strengthening,precipitation,strengthening and other means..Without the normalizing heat treatment process,the cost was reduced and the production period was also shorten.%阐述了60~80 mm 厚高层建筑用 Q460GJD-Z35钢板在南阳汉冶特钢采用100 t 转炉—LF+VD 精炼—浇注—3800 mm 轧机 TMCP 轧制的工艺研制开发过程,通过合理的化学成分设计、严格的冶炼、浇铸、合理的钢坯加热、TMCP 轧制工艺控制,最终确保了 TMCP 交货状态的60~80 mm 厚 Q460GJD-Z35钢板成功研制。采用微合金化的成分设计,通过 TMCP 工艺,充分利用细晶强化、析出强化等手段,获得了控轧状态的该钢种各项优异力学性能指标,去掉了钢板正火热处理工艺,降低成本的同时也缩短了生产周期。

  9. Free vibration Analysis of Sandwich Plates with cutout

    Science.gov (United States)

    Mishra, N.; Basa, B.; Sarangi, S. K.

    2016-09-01

    This paper presents the free vibration analysis of sandwich plates with cutouts. Cutouts are inevitable in structural applications and the presence of these cutouts in the structures greatly influences their dynamic characteristics. A finite element model has been developed here using the ANSYS 15.0 software to study the free vibration characteristics of sandwich plates in the presence of cutouts. Shell 281 element, an 8-noded element with six degrees of freedom suited for analyzing thin to moderately thick structures is considered in the development of the model. Block Lanczose method is adopted to extract the mode shapes to obtain the natural frequency corresponding to free vibration of the plate. The effects of parametric variation on the natural frequency of the sandwich plates with cutout are studied and results are presented.

  10. Aeroelastic Tailoring of a Plate Wing with Functionally Graded Materials

    Science.gov (United States)

    Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia; Jutte, Christine V.

    2014-01-01

    This work explores the use of functionally graded materials for the aeroelastic tailoring of a metallic cantilevered plate-like wing. Pareto trade-off curves between dynamic stability (flutter) and static aeroelastic stresses are obtained for a variety of grading strategies. A key comparison is between the effectiveness of material grading, geometric grading (i.e., plate thickness variations), and using both simultaneously. The introduction of material grading does, in some cases, improve the aeroelastic performance. This improvement, and the physical mechanism upon which it is based, depends on numerous factors: the two sets of metallic material parameters used for grading, the sweep of the plate, the aspect ratio of the plate, and whether the material is graded continuously or discretely.

  11. Analysis of thin plates by the weak form quadrature element method

    Institute of Scientific and Technical Information of China (English)

    ZHONG HongZhi; YUE ZhiGuang

    2012-01-01

    The recently proposed weak form quadrature element method (QEM) is applied to flexural and vibrational analysis of thin plates.The integrals involved in the variational description of a thin plate are evaluated by an efficient numerical scheme and the partial derivatives at the integration sampling points are then approximated using differential quadrature analogs.Neither the grid pattern nor the number of nodes is fixed,being adjustable according to convergence need.The C1 continuity conditions characterizing the thin plate theory are discussed and the robustness of the weak form quadrature element for thin plates against shape distortion is examined.Examples are presented and comparisons with analytical solutions and the results of the finite element method are made to demonstrate the convergence and computational efficiency of the weak form quadrature element method.It is shown that the present formulation is applicable to thin plates with varying thickness as well as uniform plates.

  12. Three-Dimensional Vibration of Thick Plate

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    1IntroductionTheclassicalthinplatetheoryofvibrationisbasedontheKirchhofhyothesis,andtheefectoftransversalsheardeformationandr...

  13. Thermo-mechanical segmentation of the Nazca plate in Central Andes

    Science.gov (United States)

    Clouard, Valerie

    2010-05-01

    The dynamics of the Chilean subduction is not uniform and presents along-strike variations controlled by plate interactions and pre-existing heterogeneity's in the upper plate. This study determines the variations of thermo-mechanical characteristics of the subducting Nazca plate before subduction, and their relations with the known South America plate segmentation. Thermal variations are derived from the regional depth anomalies of the seafloor. Seafloor depth anomalies are used to obtain maps of corrected ages and thickness of the oceanic lithosphere and compared to the heat flow anomaly data. It is abnormally colder/thicker to the north of the Iquique Ridge at 22°S and hotter/thinner to the south. Mechanical characteristics come from the shape of the bending prior to subduction. After age correction and filtering of the bathymetric data, the along-strike variations of the elastic thicness are traduced in mechanical thickness. A limit between strong and weak lithosphere appears at 28°S. To completely describe the Nazca plate and its correlation with interplate seismicity, the compositional characteristics are the third and necessary parameter. Finally, the Nazca plate can be divided in five main segments directly correlated with the seismic segmentation of the subduction. One interesting point is that the wavelength of measured lithospheric anomalies in front of the flat-slab is greater than the Juan Fernandez (JF) Ridge. It strongly suggests that it the oceanic lithosphere that is responsible for the flat-slab, and not only the JF Ridge.

  14. An accurate higher order displacement model with shear and normal deformations effects for functionally graded plates

    Energy Technology Data Exchange (ETDEWEB)

    Jha, D.K., E-mail: dkjha@barc.gov.in [Civil Engineering Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kant, Tarun [Department of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076 (India); Srinivas, K. [Civil Engineering Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Singh, R.K. [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2013-12-15

    Highlights: • We model through-thickness variation of material properties in functionally graded (FG) plates. • Effect of material grading index on deformations, stresses and natural frequency of FG plates is studied. • Effect of higher order terms in displacement models is studied for plate statics. • The benchmark solutions for the static analysis and free vibration of thick FG plates are presented. -- Abstract: Functionally graded materials (FGMs) are the potential candidates under consideration for designing the first wall of fusion reactors with a view to make best use of potential properties of available materials under severe thermo-mechanical loading conditions. A higher order shear and normal deformations plate theory is employed for stress and free vibration analyses of functionally graded (FG) elastic, rectangular, and simply (diaphragm) supported plates. Although FGMs are highly heterogeneous in nature, they are generally idealized as continua with mechanical properties changing smoothly with respect to spatial coordinates. The material properties of FG plates are assumed here to vary through thickness of plate in a continuous manner. Young's modulii and material densities are considered to be varying continuously in thickness direction according to volume fraction of constituents which are mathematically modeled here as exponential and power law functions. The effects of variation of material properties in terms of material gradation index on deformations, stresses and natural frequency of FG plates are investigated. The accuracy of present numerical solutions has been established with respect to exact three-dimensional (3D) elasticity solutions and the other models’ solutions available in literature.

  15. Reprodutibilidade das mensurações da espessura das tábuas ósseas na tomografia computadorizada Cone-Beam utilizando diferentes protocolos de aquisição de imagem Reproducibility of bone plate thickness measurements with Cone-Beam Computed Tomography using different image acquisition protocols

    Directory of Open Access Journals (Sweden)

    Carolina Carmo de Menezes

    2010-10-01

    Full Text Available INTRODUÇÃO: quanto menor a dimensão do voxel, maior a nitidez da imagem de tomografia computadorizada Cone-Beam (TCCB, porém, maior a dose de radiação emitida. OBJETIVOS: avaliar e comparar a reprodutibilidade da mensuração da espessura das tábuas ósseas vestibular e lingual em imagens de TCCB, utilizando diferentes protocolos de aquisição de imagem com variação da dimensão do voxel. MÉTODOS: exames de TCCB foram tomados de 12 mandíbulas humanas secas, com dimensão do voxel de 0,2; 0,3 e 0,4mm, no aparelho i-CAT Cone-Beam 3-D Dental Imaging System. No software i-CAT Viewer, foi mensurada a espessura das tábuas ósseas vestibular e lingual, em um corte axial passando 12mm acima do forame mentoniano do lado direito. A reprodutibilidade intraexaminador foi avaliada por meio da aplicação do teste t pareado. Para a comparação interexaminadores, foi utilizado o teste t independente. Os resultados foram considerados com o nível de significância de 5%. RESULTADOS: observou-se uma excelente reprodutibilidade interexaminadores para os três protocolos avaliados. A reprodutibilidade intraexaminadores foi muito boa, com exceção de algumas regiões dos dentes anteriores, que mostraram diferenças estatisticamente significativas, independentemente da dimensão do voxel. CONCLUSÃO: a mensuração da espessura das tábuas ósseas vestibular e lingual em imagens de TCCB mostrou boa precisão para exames obtidos com voxel de 0,2; 0,3 ou 0,4mm. A reprodutibilidade das mensurações na região anterior da mandíbula foi mais crítica do que na região posterior.INTRODUCTION: A smaller voxel dimension leads to greater resolution of Cone-Beam Computed Tomography (CBCT, but a greater dosage of radiation is emitted. OBJECTIVE: Assess and compare the reproducibility of buccal and lingual bone plate thickness measurements in CBCT images using different image acquisition protocols, with variations in the voxel dimension. METHODS: CBCT exams

  16. Mechanical behaviors of the dispersion nuclear fuel plates induced by fuel particle swelling and thermal effect II: Effects of variations of the fuel particle diameters

    Science.gov (United States)

    Ding, Shurong; Wang, Qiming; Huo, Yongzhong

    2010-02-01

    In order to predict the irradiation mechanical behaviors of plate-type dispersion nuclear fuel elements, the total burnup is divided into two stages: the initial stage and the increasing stage. At the initial stage, the thermal effects induced by the high temperature differences between the operation temperatures and the room temperature are mainly considered; and at the increasing stage, the intense mechanical interactions between the fuel particles and the matrix due to the irradiation swelling of fuel particles are focused on. The large-deformation thermo-elasto-plasticity finite element analysis is performed to evaluate the effects of particle diameters on the in-pile mechanical behaviors of fuel elements. The research results indicate that: (1) the maximum Mises stresses and equivalent plastic strains at the matrix increase with the fuel particle diameters; the effects of particle diameters on the maximum first principal stresses vary with burnup, and the considered case with the largest particle diameter holds the maximum values all along; (2) at the cladding near the interface between the fuel meat and the cladding, the Mises stresses and the first principal stresses undergo major changes with increasing burnup, and different variations exist for different particle diameter cases; (3) the maximum Mises stresses at the fuel particles rise with the particle diameters.

  17. Characterizing cycle-to-cycle variations of the shedding cycle in the turbulent wake of a normal flat plate using generalized phase averages

    Science.gov (United States)

    Martinuzzi, Robert

    2016-11-01

    Quasi-periodic vortex shedding in the turbulent wake of a thin-flat plate placed normal to a uniform stream at Reynolds number of 6700 is investigated based on Particle Image Velocimetry experiments. The wake structure and vortex formation are characterized using a generalized phase average (GPA), a refinement of the triple decomposition of Reynolds and Hussain (1970) incorporating elements of mean-field theory (Stuart, 1958). The resulting analysis highlights the importance of cycle-to-cycle variations in characterizing vortex formation, wake topology and the residual turbulent Reynolds Stresses. For example, it is shown that during high-amplitude cycles vorticity is strongly concentrated within the well-organized shed vortices, whereas during low-amplitude cycles the shed vortices are highly distorted resulting in significant modulation of the shedding frequency. It is found that high-amplitude cycles contribute more to the coherent Reynolds stress field while the low-amplitude cycles contribute to the residual stress field. It is further shown that traditional phase-averaging techniques lead to an over-estimation of the residual stress field. Natural Sciences and Engineering Research Council of Canada.

  18. Linear free flexural vibration of cracked functionally graded plates in thermal environment

    CERN Document Server

    Natarajan, S; Ganapathi, M; Kerfriden, P; Bordas, S; 10.1016/j.compstruc.2011.04.002

    2011-01-01

    In this paper, the linear free flexural vibrations of functionally graded material plates with a through center crack is studied using an 8-noded shear flexible element. The material properties are assumed to be temperature dependent and graded in the thickness direction. The effective material properties are estimated using the Mori-Tanaka homogenization scheme. The formulation is developed based on first-order shear deformation theory. The shear correction factors are evaluated employing the energy equivalence principle. The variation of the plates natural frequency is studied considering various parameters such as the crack length, plate aspect ratio, skew angle, temperature, thickness and boundary conditions. The results obtained here reveal that the natural frequency of the plate decreases with increase in temperature gradient, crack length and gradient index.

  19. Along-strike thickness variations of décollement levels controlling lateral changes in fold-and-thrust belts: the Barbastro-Balaguer Anticline (Southern Pyrenees)

    Science.gov (United States)

    Santolaria, Pablo; Calvín, Pablo; Pueyo, Emilio L.; Soto, Ruth; Ayala, Concepción; Casas, Antonio; Oliván, Carlota; Luzón, Aránzazu

    2017-04-01

    Marginal Ranges) depicts mainly a ramp-flat geometry. Southwards, on the autochthonous deformation zone, the Barbastro-Balaguer Anticline (BBA) structure, which core is constituted by Eocene evaporites, seems to mimic the geometry of the SPFT. It displays a lateral change, from east to west, in both its orientation (N110E to N160E) and geometry (anticline to backthrust structure) probably linked to an important lateral thickness variation (as deduce from the residual anomaly map) of the Eocene evaporites that display a significant accumulation in the east and thin drastically and even disappear to the west. There, its distal pinch out is interpreted to promote the nucleation of the BBA backthrust. The distribution of the Eocene evaporites in the subsurface and the lateral changes in thickness are suggested to be significant factors during the late stages of the emplacement of the SPFT and associated structures.

  20. Optimization Design of Thermal Conduction Enhanced PCM Plates for Simulating the Infrared Signature of Steel Plate

    Institute of Scientific and Technical Information of China (English)

    YE Hong; JIANG Li-feng

    2008-01-01

    Phase change material (PCM) can be used to prepare the infrared false targets for realizing all-weather passive infrared decoy, but its low thermal conductivity is a great blockage to the simulation of the infrared signature of thick metal plates. For that reason, a method of simulating the infrared signature of thick steel plates by thermal conduction enhanced PCM, including the aluminum fins, is proposed. A physical and mathematic model is set up, and the infrared signature simulation of thick steel plate is investigated numerically. The effects of the distribution density and thickness of fins and the thickness of PCM plate on the simulation results are discussed, and the reasonable construction parameters of PCM plates used to simulate the steel plates of different thickness are obtained.

  1. Geometry and spatial variations of seismic reflection intensity of the upper surface of the Philippine Sea plate off the Boso Peninsula, Japan

    Science.gov (United States)

    Kono, Akihiro; Sato, Toshinori; Shinohara, Masanao; Mochizuki, Kimihiro; Yamada, Tomoaki; Uehira, Kenji; Shinbo, Takashi; Machida, Yuya; Hino, Ryota; Azuma, Ryousuke

    2017-07-01

    In the region off the Boso Peninsula, Japan, the Pacific plate is subducting westward beneath both the Honshu island arc and Philippine Sea plate, while the Philippine Sea plate is subducting northwestward beneath the Honshu island arc. These complex tectonic interactions have caused numerous seismic events occurred in the past. To better understand these seismic events, it is important to determine the geometry of the plate boundary, in particular the upper surface of the Philippine Sea plate. We conducted an active-source seismic refraction survey in July and August 2009 from which we obtained a 2-D P-wave velocity structure model along a 216-km profile. We used the velocity model and previously published data that indicate a P-wave velocity of 5.0 km/s for the upper surface of the subducting Philippine Sea plate to delineate its boundary with the overriding Honshu island arc. Our isodepth contours of the upper surface of the Philippine Sea plate show that its dip is shallow at depths of 10 to 15 km, far off the Boso Peninsula. This shallow dip may be a result of interference from the Pacific plate slab, which is subducting westward under the Philippine Sea plate. Within our survey data, we recognized numerous seismic reflections of variable intensity, some of which came from the upper surface of the Philippine Sea plate. An area of high seismic reflection intensity corresponds with the main slip area of the Boso slow slip events. Our modeling indicates that those reflections can be explained by an inhomogeneous layer close to the upper surface of the Philippine Sea plate.

  2. Variation in the ADIPOQ gene promoter is associated with carotid intima media thickness independent of plasma adiponectin levels in healthy subjects

    National Research Council Canada - National Science Library

    Patel, Sheila; Flyvbjerg, Allan; Kozàkovà, Michaela; Frystyk, Jan; Ibrahim, Ibrahim M; Petrie, John R; Avery, Peter J; Ferrannini, Ele; Walker, Mark

    2008-01-01

    .... We investigated the role of the ADIPOQ gene single-nucleotide polymorphisms (SNPs) A-11426G, G-11391A, C-11377G, and T45G with plasma adiponectin levels and common carotid artery intima media thickness (IMT...

  3. Origami - Folded Plate Structures

    OpenAIRE

    Buri, Hans Ulrich

    2010-01-01

    This research investigates new methods of designing folded plate structures that can be built with cross-laminated timber panels. Folded plate structures are attractive to both architects and engineers for their structural, spatial, and plastic qualities. Thin surfaces can be stiffened by a series of folds, and thus not only cover space, but also act as load bearing elements. The variation of light and shadow along the folded faces emphasizes the plas...

  4. Temperature field of steel plate cooling process after plate rolling

    Directory of Open Access Journals (Sweden)

    Huijun Feng, Lingen Chen, Fengrui Sun

    2015-01-01

    Full Text Available Based on numerical calculation with Matlab, the study on cooling process after plate rolling is carried out, and the temperature field distribution of the plate varying with the time is obtained. The effects of the plate thickness, final rolling temperature, cooling water temperature, average flow rate of the cooling water, carbon content of the plate and cooling method on the plate surface and central temperatures as well as final cooling temperature are discussed. For the same cooling time, the plate surface and central temperatures as well as their temperature difference increase; with the decrease in rolling temperature and the increase in average flow rate of the cooling water, the plate surface and central temperatures decrease. Compared with the single water cooling process, the temperature difference between the plate centre and surface based on intermittent cooling is lower. In this case, the temperature uniformity of the plate is better, and the corresponding thermal stress is lower. The fitting equation of the final cooling temperature with respect to plate thickness, final rolling temperature, cooling water temperature and average flow rate of the cooling water is obtained.

  5. GA-based PID control of the plate width in hot-plate mills

    Science.gov (United States)

    Kim, Byungman; Lee, Dae Y.; Cho, Hyungsuck

    1999-11-01

    In hot plate mills the slabs from incoming reheat furnace are reduced to the desired width and thickness, being rolled out with considerable accuracy. The process of changing the plate width is controlled by a pair of edge rolls, which is called edger. The objectives of this edging process are to meet tight width tolerances of plates and to reduce the yield loss caused by trimming when irregular width is formed at the plate edge. There are several factors that result in complexity and uncertainty in width control. These include inaccurate edger set-up model, degradation of various mill equipment, variation of operation conditions, environments and variation of the dimension of incoming cast slabs. In this paper, a genetic algorithm-based PID control is proposed to ensure the control of the desired width at the exit of the mill. The approach adopted here is essentially optimization of the PID controller gains in order to minimize the error between the desired and actual slab width. Since the design parameters associated with genetic algorithm affect convergence performance, the effects of these parameters are investigated in detail. In addition, the control performance is also evaluated for various process parameters such as initial width of the incoming slab and temperature of the slab. Based on the result obtained from a series of simulations, the proposed control method is found to yield satisfactory performance for various process conditions.

  6. The effects of the overriding plate thermal state on the slab dip in an ocean-continent subduction system

    CERN Document Server

    Roda, Manuel; Spalla, Maria Iole; 10.1016/j.crte.2011.01.005

    2011-01-01

    To evaluate the effects of variations in the thermal state of the overriding plate on the slab dip in an ocean-continent subduction system, a 2-D finite element thermo-mechanical model was implemented. The lithosphere base was located at the depth of the 1600 K isotherm. Numerical simulations were performed while taking into account four different initial thicknesses for the oceanic lithosphere (60, 80, 95 and 110 km) and five different thicknesses of the overriding plate, as compared in terms of the continental-oceanic plate thickness ratio (100, 120, 140, 160 and 200% of the oceanic lithosphere thickness). The results of numerical modeling indicate that a high variability of the subducting plate geometry occurs for an oceanic lithosphere thickness ranging from 60 to 80 km, while the variability decreases where the oceanic plates are thicker (95 and 110 km). Furthermore, the slab dip strongly depends on the thermal state of the overriding plate, and, in particular, the slab dip decreases with the increase in...

  7. The effects of slice thickness and radiation dose level variations on computer-aided diagnosis (CAD) nodule detection performance in pediatric chest CT scans

    Science.gov (United States)

    Emaminejad, Nastaran; Lo, Pechin; Ghahremani, Shahnaz; Kim, Grace H.; Brown, Matthew S.; McNitt-Gray, Michael F.

    2017-03-01

    For pediatric oncology patients, CT scans are performed to assess treatment response and disease progression. CAD may be used to detect lung nodules which would reflect metastatic disease. The purpose of this study was to investigate the effects of reducing radiation dose and varying slice thickness on CAD performance in the detection of solid lung nodules in pediatric patients. The dataset consisted of CT scans of 58 pediatric chest cases, from which 7 cases had lung nodules detected by radiologist, and a total of 28 nodules were marked. For each case, the original raw data (sinogram data) was collected and a noise addition model was used to simulate reduced-dose scans of 50%, 25% and 10% of the original dose. In addition, the original and reduced-dose raw data were reconstructed at slice thicknesses of 1.5 and 3 mm using a medium sharp (B45) kernel; the result was eight datasets (4 dose levels x 2 thicknesses) for each case An in-house CAD tool was applied on all reconstructed scans, and results were compared with the radiologist's markings. Patient level mean sensitivities at 3mm thickness were 24%, 26%, 25%, 27%, and at 1.5 mm thickness were 23%, 29%, 35%, 36% for 10%, 25%, 50%, and 100% dose level, respectively. Mean FP numbers were 1.5, 0.9, 0.8, 0.7 at 3 mm and 11.4, 3.5, 2.8, 2.8 at 1.5 mm thickness for 10%, 25%, 50%, and 100% dose level respectively. CAD sensitivity did not change with dose level for 3mm thickness, but did change with dose for 1.5 mm. False Positives increased at low dose levels where noise values were high.

  8. Nonlocal Elasticity Theory for Transient Analysis of Higher-Order Shear Deformable Nanoscale Plates

    Directory of Open Access Journals (Sweden)

    Woo-Young Jung

    2014-01-01

    Full Text Available The small scale effect on the transient analysis of nanoscale plates is studied. The elastic theory of the nano-scale plate is reformulated using Eringen’s nonlocal differential constitutive relations and higher-order shear deformation theory (HSDT. The equations of motion of the nonlocal theories are derived for the nano-scale plates. The Eringen’s nonlocal elasticity of Eringen has ability to capture the small scale effects and the higher-order shear deformation theory has ability to capture the quadratic variation of shear strain and consequently shear stress through the plate thickness. The solutions of transient dynamic analysis of nano-scale plate are presented using these theories to illustrate the effect of nonlocal theory on dynamic response of the nano-scale plates. On the basis of those numerical results, the relations between nonlocal and local theory are investigated and discussed, as are the nonlocal parameter, aspect ratio, side-to-thickness ratio, nano-scale plate size, and time step effects on the dynamic response. In order to validate the present solutions, the reference solutions are employed and examined. The results of nano-scale plates using the nonlocal theory can be used as a benchmark test for the transient analysis.

  9. Influence of adhesive layer properties on laser-generated ultrasonic waves in thin bonded plates

    Institute of Scientific and Technical Information of China (English)

    Sun Hong-Xiang; Xu Bai-Qiang; Zhang Hua; Gao Qian; Zhang Shu-Yi

    2011-01-01

    This paper studies quantitatively the generation of Lamb waves in thin bonded plates subjected to laser illumination, after considering the viscoelasticity of the adhesive layer. The displacements of such plates have been calculated in the frequency domain by using the finite element method, and the time domain response has been reconstructed by applying an inverse fast Fourier transform. Numerical results are presented showing the normal surface displacement for several configurations: a single aluminum plate, a three-layer bonded plate, and a two-layer plate. The characteristics of the laser-generated Lamb waves for each particular case have been investigated. In addition, the sensitivity of the transient responses to variations of material properties (elastic modulus, viscoelastic modulus, and thickness) of the adhesive layer has been studied in detail.

  10. TC4钛合金厚板潜弧焊接头的显微组织%Microstructure of Submerged Arc Welded Joint of TC4 Titanium Alloy Thick Plate

    Institute of Scientific and Technical Information of China (English)

    杨剑赟; 邢丽; 黄春平; 柯黎明

    2011-01-01

    The TC4 titanium alloy plates with 45 mm thickness was welded by using double-sided submerged arc welding method, and then obtained the defect-free butt joint. The microstructure of welded joint was observed by optical microscopy. The results show that the microstructure of weld seam was β columnar grains, which consisted of basket-like α'martensite. The lath α' martensite was formed because the effect of the later weld seam on prior weld seam. The acicular aI martensite was formed for a short residence time for lacter weld seam at high temperature; HAZ comprised part recrystal zone, transition zone, fine grain zone and coarse grain zone, the grains in HAZ were equiaxed but with different sizes and forms. The part recrystal zone consisted of equiaxed structure of α and β, transition zone consisted of equiaxed α and acicular α' martensite and remained β grain; fine grain zone consisted of acicular α' martensite and remain β grain, coarse-grain zone consisted of basket-like α' and remained grain.%采用双面潜弧焊焊接了45mm厚的TC4钛合金,得到了内部无缺陷的对接接头,采用光学显微镜分析了接头的显微组织。结果表明:焊缝为β柱状晶,柱状晶内为α’马氏体组成的网篮组织,先焊焊缝受后一道焊缝影响,α’马氏体呈条状,后焊焊缝高温停留时间较短,冷却后α’马氏体为针状;热影响区分为部分重结晶区、过渡区、细晶区与粗晶区,且皆为等轴晶,但尺寸及形态不同;部分重结晶区为等轴α、β组织;过渡区为等轴Ct、针状α’马氏体和残留β晶粒组织;细晶区则为针状α’马氏体和残留β晶粒;粗晶区组织为网篮状α‘氏体和残留β晶粒。

  11. 厚板铝合金变极性等离子弧焊工艺%Research on VPPA helium arc welding process of thick Al-Mg alloy plate

    Institute of Scientific and Technical Information of China (English)

    薛根奇; 马丽

    2012-01-01

    分析铝镁合金的焊接特性和变极性等离子弧焊的焊接特点及氩-氦电弧的特性,依据8~12 mm板厚5083的焊接经验,选用变极性等离子孤焊,分别采用氩气、氩气+氦气作为保护气体,对16 mm厚的5083铝合金进行焊接试验,通过优化焊接工艺参数,获得良好的焊缝成形;按JB/T 4730《承压设备无损检测》的要求对获得的焊接接头进行射线检测和渗透检测,通过机械性能试验验证焊接接头的机械性能,各项检测及试验结果均符合NB/T 47014《承压设备焊接工艺评定》的要求,获得的焊接工艺规范参数在高压封闭电器外壳筒体的焊接中稳定应用.%Based on the welding properties of aluminum-magnesium alloy,the welding characteristics of variable polarity plasma arc welding (VPPAW)and Argon-helium mixed arc,relay on the practical experience of 8-12mm 5083 alloy in variable polarity plasma arc welding,The variable polarity plasma helium arc welding was used to weld 16mm thick plate 5083 alloy with Argon and Argon-helium gas;Optimized welding parameters by study on die welding process,Gain the welded joints with Excellent weld shape,perfect internal quality and excellent mechanical properties. Use the non-destructive testing of pressure equipment of RT and FT to verify the weld surface and internal quality, verified the mechanical properties of welded joints by mechanical properties tests;The test results in line with the NB/T 47014"welding procedure qualification for pressure equipment",The welding process specification parameters are stable application in the welding of high pressure closed electrical enclosure tube.

  12. WAVELET-BASED MODEL OF PIEZOELECTRIC VIBRATION CONTROL FOR CANTILEVERED BEAM-PLATES WITH VARIABLE THICKNESS%变截面梁式压电智能板振动控制的小波模式

    Institute of Scientific and Technical Information of China (English)

    周又和; 王记增; 郑晓静

    2001-01-01

    基于Daubechies小波理论的尺度函数变换,对于变截面悬臂板结构的弯曲建立了由压电片感应器的观测电量识别挠曲变形构形的显式关系式。此基础上,采用具有位移与速度信号负反馈控制律后,建立了抑制振动的压电动力控制程序。由于小波尺度函数逼近具有低带通性质,即具有自动滤除高频分量的能力,该控制程序将不会出现由观测溢出与控制溢出耦合而造成的控制失稳(即在抑制低频(阶)扰动时系统激发出高频(阶)扰动的现象)。数值仿真结果表明:该控制方法所能控制的模态阶数与压电片数相同,而且其控制程序在抑制外界干扰方面是有效的。%Based on the scaling function transform of the Daubechies wavelet theory, an explicit expression of identification of deflection for cantilevered beam-plates with variable thickness is obtained by the measurable electric charges and electricity from the piezoelectric sensors attached on the structures. After that, a control programme to the control system with piezoelectric sensors and actuators is established by means of a control law of feedback of negative signals of the identified deflection and its velocity to suppress vibrations of the structures. Due to the characteristic that the scaling function transform has a function of low-pass filter which can auto-filter out those signals of higher-order dependent upon the resolution level of the wavelet theory, this control program on the basis of the wavelet theory can avoid the phenomenon of control instability that is caused by the coupling of spilling over of sensing and actuating, or in other words, that some higher-order vibrations are excited when a lower-order vibration is suppressed. The numerical simulations show that this control program can effectively suppress those disturbances spread from the lower-order modals of the structure when the number of order of the disturbance is not greater

  13. The Role of Philippine Sea Plate to the Genesis of Quaternary Magmas of Northern Kyushu Island, Japan, Inferred from Along-Arc Geochemical Variations

    Science.gov (United States)

    Shibata, T.; Yoshikawa, M.; Itoh, J.; Ujike, O.; Miyoshi, M.; Takemura, K.

    2013-12-01

    Quaternary volcanoes on Kyushu Island comprise volcanoes Himeshima, Futagoyama, Yufu-Tsurumi, Kuju, Aso, Kirishima and Sakurajima from north to south alongstrike the volcanic front. Adakitic lavas are observed from Yufu-Tsurumi and Kuju volcanoes in northern Kyushu (Kita et al., 2001; Sugimoto et al., 2007), whereas no Quaternary adakites were observed at Aso (e.g., Hunter, 1998) and the volcanoes south of Aso along the entire Ryukyu arc. Sugimoto et al. (2007) suggested that the trace element and Sr, Nd, and Pb isotopic compositions of adakitic magmas from Yufu-Tsurumi volcano indicate derivation of the magmas by partial melting of the subducting PSP. In contrast, Zellmer et al. (2012) suggested that these adakites may have formed by fractional crystallization of mantle-derived mafic magmas within the garnet stability field in the crust. The Honshu-Kyushu arc transition is a particular favorable setting to address these controversial models for the origin of the adakitic lavas, because of the potential relationship between the PSP materials and the alongstrike variation of the lava chemistry. The Palau-Kyushu ridge divides the oceanic crust of the PSP into northeastern and southwestern segments with ages of 26-15 (Shikoku Basin) and 60-40 Ma (West Philippine Basin), respectively (Mahony et al., 2011). Although there are no clear plate images beneath northern Kyushu, the northern extension of the Palau-Kyushu ridge potentially corresponds to the boundary between the SW Japan and Ryukyu arcs. If adakite genesis was related to the subducted slab rather than the overlying crust, then the spatial distribution of Quaternary adakites should correlate with the age of the subducted PSP. In order to test such correlation and elucidate the petrogenesis of the northern Kyushu adakites, we compiled major and trace elements and Sr-Nd-Pb isotope ratios from volcanoes along the arc front that includes the transition from adakitic to non-adakitic arc volcanism. Comprehensive

  14. Pixelated neutron image plates

    Science.gov (United States)

    Schlapp, M.; Conrad, H.; von Seggern, H.

    2004-09-01

    Neutron image plates (NIPs) have found widespread application as neutron detectors for single-crystal and powder diffraction, small-angle scattering and tomography. After neutron exposure, the image plate can be read out by scanning with a laser. Commercially available NIPs consist of a powder mixture of BaFBr : Eu2+ and Gd2O3 dispersed in a polymer matrix and supported by a flexible polymer sheet. Since BaFBr : Eu2+ is an excellent x-ray storage phosphor, these NIPs are particularly sensitive to ggr-radiation, which is always present as a background radiation in neutron experiments. In this work we present results on NIPs consisting of KCl : Eu2+ and LiF that were fabricated into ceramic image plates in which the alkali halides act as a self-supporting matrix without the necessity for using a polymeric binder. An advantage of this type of NIP is the significantly reduced ggr-sensitivity. However, the much lower neutron absorption cross section of LiF compared with Gd2O3 demands a thicker image plate for obtaining comparable neutron absorption. The greater thickness of the NIP inevitably leads to a loss in spatial resolution of the image plate. However, this reduction in resolution can be restricted by a novel image plate concept in which a ceramic structure with square cells (referred to as a 'honeycomb') is embedded in the NIP, resulting in a pixelated image plate. In such a NIP the read-out light is confined to the particular illuminated pixel, decoupling the spatial resolution from the optical properties of the image plate material and morphology. In this work, a comparison of experimentally determined and simulated spatial resolutions of pixelated and unstructured image plates for a fixed read-out laser intensity is presented, as well as simulations of the properties of these NIPs at higher laser powers.

  15. High-resolution image of the geometry and thickness of the subducting Nazca lithosphere beneath northern Chile

    Science.gov (United States)

    Sodoudi, F.; Yuan, X.; Asch, G.; Kind, R.

    2011-04-01

    Results obtained from S and P receiver functions produced a clear image of the top and bottom of the subducting Nazca lithosphere beneath northern Chile. Using data from the teleseismic events recorded at 15 permanent Integrated Plate Boundary Observatory Chile (IPOC) stations, we obtained new constraints on the geometry and thickness of the descending Nazca lithosphere. We observed the subducted crust of the Nazca plate at depths ranging from 50 km beneath the Coastal Cordillera down to 110 km beneath the Western Cordillera. We found significant along-strike variations in the geometry of the Nazca plate beneath northern Chile. On closer inspection, it appears that the oceanic Nazca plate is divided into two distinct segments as it descends beneath the continental South American plate. The transition from the relatively steeper (˜23°) and deeper slab to the north of 21°S to the flatter southern segment (˜19°) is shown reasonably clearly by our data. This feature could well be associated with variations in the curvature of the plate margin and the geometry of the Chile trench, which is mainly curved to the north of 21°S. We have also mapped the continental Moho of the South American plate at depths ranging between 60 and 70 km to the east of the Longitudinal Valley. Beneath the Coastal Cordillera, this boundary becomes invisible, probably due to the serpentinization of the forearc mantle wedge that reduces the velocity in the uppermost mantle. The base of the subducted Nazca plate was clearly identified as a sharp boundary in the results obtained from the P and S receiver functions. The thickness of the subducted oceanic Nazca plate, which has an age of ˜50 My, is estimated to be ˜50 km. Although this thickness is consistent with that predicted by thermal gradients, the explanation of the sharpness of the lithosphere-asthenosphere boundary may require another mechanism such as hydration or melting.

  16. A Comparative Assessment of Track Plates to Quantify Fine Scale Variations in the Relative Abundance of Norway Rats in Urban Slums.

    Science.gov (United States)

    Hacker, Kathryn P; Minter, Amanda; Begon, Mike; Diggle, Peter J; Serrano, Soledad; Reis, Mitermayer G; Childs, James E; Ko, Albert I; Costa, Federico

    2016-06-01

    Norway rats (Rattus norvegicus) living in urban environments are a critical public health and economic problem, particularly in urban slums where residents are at a higher risk for rat borne diseases, yet convenient methods to quantitatively assess population sizes are lacking. We evaluated track plates as a method to determine rat distribution and relative abundance in a complex urban slum environment by correlating the presence and intensity of rat-specific marks on track plates with findings from rat infestation surveys and trapping of rats to population exhaustion. To integrate the zero-inflated track plate data we developed a two-component mixture model with one binary and one censored continuous component. Track plate mark-intensity was highly correlated with signs of rodent infestation (all coefficients between 0.61 and 0.79 and all p-values < 0.05). Moreover, the mean level of pre-trapping rat-mark intensity on plates was significantly associated with the number of rats captured subsequently (Odds ratio1.38; 95% CI 1.19-1.61) and declined significantly following trapping (Odds ratio 0.86; 95% CI 0.78-0.95). Track plates provided robust proxy measurements of rat abundance and distribution and detected rat presence even when populations appeared 'trapped out'. Tracking plates are relatively easy and inexpensive methods that can be used to intensively sample settings such as urban slums, where traditional trapping or mark-recapture studies are impossible to implement, and therefore the results can inform and assess the impact of targeted urban rodent control campaigns.

  17. 搅拌摩擦焊AA7075-T651铝合金厚板的显微组织和力学性能%Microstructure and mechanical properties of friction stir welded AA7075-T651 aluminum alloy thick plates

    Institute of Scientific and Technical Information of China (English)

    T SRINIVASA RAO; G MADHUSUDHAN REDDY; S R KOTESWARA RAO

    2015-01-01

    研究厚度为10和16 mm AA7075-T651板的搅拌摩擦焊接过程。通过仔细选择焊接过程参数可获得无缺陷、全渗透焊接样品。两种焊接接头都出现极细的再结晶粒,而10 mm厚板焊接接头的晶粒组织更细。试样的显微组织观察结果表明,焊件热影响区的硬度显著降低。16 mm厚合金板焊接接头的硬度降低较大。与16 mm厚合金板相比,10 mm厚合金板焊件具有较优的拉伸性能。在拉伸实验过程中,两种厚度的合金板焊件均在热影响区发生断裂。样品的 TEM 结果表明,热影响区由沿晶界的宽化无沉积区和晶体内沉淀的部分溶解组成。因此,采用搅拌摩擦焊在AA7075-T651上可制得单道次无缺陷焊件,且10 mm厚合金板焊件表现出较高的焊接效率。%Friction stir butt welding of AA7075−T651 plates with thicknesses of 10 and 16 mm was investigated. Defect-free, full- penetration welds were obtained after careful process parameter selection. While the nuggets in both welds exhibited very fine recrystallized grains, and finer grains were observed in welds made on 10 mm thick plates. Microhardness surveys revealed that significant loss in hardness occurs in the heat-affected zone. The reduction in hardness due to the welding process is higher in the case of welds made on 16 mm thick plates. Welds made on 10 mm thick plates exhibited superior tensile properties compared with those made on 16 mm thick plates. Fracture during tensile test occurred in the heat-affected zone in both cases. TEM images of specimens revealed that the heat-affected zone consisted of widened precipitate-free zones along grain boundaries and partial dissolution of precipitates in the grain interiors. It is concluded that defect-free single pass welds can be made on AA7075−T651 thick plates using friction stir welding and the welds made on 10 mm thick plates exhibit high joint efficiency.

  18. Dose distribution near thin titanium plate for skull fixation irradiated by a 4-MV photon beam

    Directory of Open Access Journals (Sweden)

    Shimozato Tomohiro

    2010-01-01

    Full Text Available To investigate the effects of scattered radiation when a thin titanium plate (thickness, 0.05 cm used for skull fixation in cerebral nerve surgery is irradiated by a 4-MV photon beam. We investigated the dose distribution of radiation inside a phantom that simulates a human head fitted with a thin titanium plate used for post-surgery skull fixation and compared the distribution data measured using detectors, obtained by Monte Carlo (MC simulations, and calculated using a radiation treatment planning system (TPS. Simulations were shown to accurately represent measured values. The effects of scattered radiation produced by high-Z materials such as titanium are not sufficiently considered currently in TPS dose calculations. Our comparisons show that the dose distribution is affected by scattered radiation around a thin high-Z material. The depth dose is measured and calculated along the central beam axis inside a water phantom with thin titanium plates at various depths. The maximum relative differences between simulation and TPS results on the entrance and exit sides of the plate were 23.1% and − 12.7%, respectively. However, the depth doses do not change in regions deeper than the plate in water. Although titanium is a high-Z material, if the titanium plate used for skull fixation in cerebral nerve surgery is thin, there is a slight change in the dose distribution in regions away from the plate. In addition, we investigated the effects of variation of photon energies, sizes of radiation field and thickness of the plate. When the target to be irradiated is far from the thin titanium plate, the dose differs little from what it would be in the absence of a plate, though the dose escalation existed in front of the metal plate.

  19. Bond length variation in In0.25Ga0.75As/InP epitaxial layers thicker than the critical thickness

    Science.gov (United States)

    Tormen, M.; De Salvador, D.; Natali, M.; Drigo, A.; Romanato, F.; Rossetto, G.; Boscherini, F.; Mobilio, S.

    1999-09-01

    We address the issue of the local structure in an epitaxial semiconductor thin film undergoing strain relaxation due to extended defects when the critical thickness for their introduction is exceeded. The nearest neighbor environment is probed by x-ray absorption fine structure spectroscopy. The particular system studied is a set of In0.25Ga0.75As films grown on InP(001) of increasing thickness; the thicknesses were chosen so as to obtain a varying degree of relaxation, ranging from pseudomorphic growth to completely relaxed state. The samples have been thoroughly characterized with complementary structural techniques and the residual strain is measured by x-ray diffraction. We find that the Ga-As bond length exhibits a linear decrease with decreasing residual strain. By comparing these results with previous studies on bond lengths in pseudomorphic InxGa1-xAs films as a function of concentration we conclude that the bond lengths have an identical behavior as a function of the mean residual strain independently from its elastic or plastic origin. This result is reproduced by an analytical model based on the transfer of the mean macroscopic deformation at a local level. The broadening of the bond length distribution induced by extended defects is also discussed, concluding that it is not experimentally dectable.

  20. Asymptotic modelling of a thermopiezoelastic anisotropic smart plate

    Science.gov (United States)

    Long, Yufei

    Motivated by the requirement of modelling for space flexible reflectors as well as other applications of plate structures in engineering, a general anisotropic laminated thin plate model and a monoclinic Reissner-Mindlin plate model with thermal deformation, two-way coupled piezoelectric effect and pyroelectric effect is constructed using the variational asymptotic method, without any ad hoc assumptions. Total potential energy contains strain energy, electric potential energy and energy caused by temperature change. Three-dimensional strain field is built based on the concept of warping function and decomposition of the rotation tensor. The feature of small thickness and large in-plane dimension of plate structure helped to asymptotically simplify the three-dimensional analysis to a two-dimensional analysis on the reference surface and a one-dimensional analysis through the thickness. For the zeroth-order approximation, the asymptotically correct expression of energy is derived into the form of energetic equation in classical laminated plate theory, which will be enough to predict the behavior of plate structures as thin as a space flexible reflector. A through-the-thickness strain field can be expressed in terms of material constants and two-dimensional membrane and bending strains, while the transverse normal and shear stresses are not predictable yet. In the first-order approximation, the warping functions are further disturbed into a high order and an asymptotically correct energy expression with derivatives of the two-dimensional strains is acquired. For the convenience of practical use, the expression is transformed into a Reissner-Mindlin form with optimization implemented to minimize the error. Transverse stresses and strains are recovered using the in-plane strain variables. Several numerical examples of different laminations and shapes are studied with the help of analytical solutions or shell elements in finite element codes. The constitutive relation is

  1. Experimental investigations of sandwich panels using high performance concrete thin plates exposed to fire

    DEFF Research Database (Denmark)

    Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

    2015-01-01

    temperatures for panels with 30 mm thick plates stiffened by structural ribs, thick insulation layers, and steel shear connecting systems. Parametric variation assessing the role of each component of the sandwich structure was performed on unloaded specimens of reduced size. Full size walls were tested......Structural sandwich panels using thin high performance concrete (HPC) plates offer a possibility to address the modern environmental challenges faced by the construction industry. Fire resistance is a major necessity in structures using HPC. This paper presents experimental studies at elevated...... plate and one of them experienced heavy heat-induced spalling. Results highlighted insulation shear failure from differential thermal expansion at the interface with concrete. It suggests the existence of a high bond level between the two materials which might allow structural applications at early age...

  2. Plate tectonics conserves angular momentum

    Directory of Open Access Journals (Sweden)

    C. Bowin

    2009-03-01

    Full Text Available A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4 E+27 kgm2s−1. Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates. Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth. The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant velocity on the crests of convection cells driven by rising heat. These results imply that spreading centers are primarily passive reactive

  3. Interfacial heat transfer in squeeze casting of magnesium alloy AM60 with variation of applied pressures and casting wall-thicknesses

    Science.gov (United States)

    Zhang, Xuezhi; Fang, Li; Sun, Zhizhong; Hu, Henry; Nie, Xueyuan; Tjong, Jimi

    2016-10-01

    The heat transfer coefficient at the casting-die interface is the most important factor on the solidification process. With the 75-ton hydraulic press machine and P20 steel die mold, 5-step castings of magnesium alloy AM60 with different wall-thicknesses (3, 5, 8, 12, 20 mm) were poured under various hydraulic pressures (30, 60, and 90 MPa) using an indirect squeeze casting process. Thermal histories throughout the die wall and the casting surface have been recorded by fine type-K thermocouples. The in-cavity local pressures measured by pressure transducers were explored at the casting-die interfaces of 5 steps. The casting-die interfacial heat transfer coefficients (IHTC) initially reached a maximum peak value followed by a gradually decline to the lower level. Similar characteristics of IHTC peak values can be observed at the applied pressures of 30, 60 and 90 MPa. With the applied pressure of 90 MPa, the peak IHTC values from steps 1 to 5 varied from 5623 to 10,649 W/m2 K. As the applied hydraulic pressure increased, the IHTC peak value of each step was increased accordingly. The wall thickness also affected IHTC peak values significantly. The peak IHTC value and heat flux increased as the step became thicker. The empirical equations relating the IHTCs to the local pressures and the solidification temperature at the casting surface were developed based on the multivariate linear and polynomial regression.

  4. Oscillatory behavior of the tunnel magnetoresistance due to thickness variations in Ta|CoFe|MgO magnetic tunnel junctions: A first-principles study

    Science.gov (United States)

    Sankaran, K.; Swerts, J.; Couet, S.; Stokbro, K.; Pourtois, G.

    2016-09-01

    To investigate the impact of both the CoFe ferromagnetic layer thickness and the capping paramagnetic layer on the tunnel magnetoresistance (TMR), we performed first-principles simulations on epitaxial magnetic tunnel junctions contacted with either CoFe or Ta paramagnetic capping layers. We observed a strong oscillation of the TMR amplitude with respect to the thickness of the ferromagnetic layer. The TMR is found to be amplified whenever the MgO spin tunnel barrier is thickened. Quantization of the electronic structure of the ferromagnetic layers is found to be at the origin of this oscillatory behavior. Metals such as Ta contacting the magnetic layer are found to enhance the amplitude of the oscillations due to the occurrence of an interface dipole. The latter drives the band alignment and tunes the nature of the spin channels that are active during the tunneling process. Subsequently, the regular transmission spin channels are modulated in the magnetic tunnel junction stack and other complex ones are being activated.

  5. Measurement of optical loss variation on thickness of InGaN optical confinement layers of blue-violet-emitting laser diodes

    Science.gov (United States)

    Son, J. K.; Lee, S. N.; Paek, H. S.; Sakong, T.; Kim, H. K.; Park, Y.; Ryu, H. Y.; Nam, O. H.; Hwang, J. S.; Cho, Y. H.

    2008-05-01

    An optical loss of GaN-based blue-violet laser diodes (BV-LDs) was measured by taking the intensity decay of edge emitting luminescence with respect to the distance from cleaved edge of a wafer to the position where an excitation laser was focused. Amplified spontaneous emission (ASE) was also investigated by tuning the power of an excitation laser on BV-LD wafers. Measurements were performed on wafers with different thicknesses of InGaN optical confinement layers (OCLs). The threshold power of ASE intensity was minimized at an optimum thickness of InGaN OCL. We also found that optical loss of wafers was determined by absorption of an InGaN layer in thicker OCL structure. From experimental data and fittings, we obtained 40 cm-1 for InGaN absorption at 405 nm. The optical field confined in OCL region was reasonably high enough to affect the overall modal loss in devices. Therefore, the optical losses still remained even though the Mg-doped GaN regions are far enough from the active layers. The crystal quality of an InGaN layer should be an important aspect to improve the performance of BV-LDs.

  6. Nonlinear free flexural vibrations of functionally graded rectangular and skew plates under thermal environments

    CERN Document Server

    Sundararajan, N; Ganapathi, M; 10.1016/j.finel.2005.06.001

    2011-01-01

    The nonlinear formulation developed based on von Karman's assumptions is employed to study the free vibration characteristics of functionally graded material (FGM) plates subjected to thermal environment. Temperature field is assumed to be a uniform distribution over the plate surface and varied in the thickness direction. The material is assumed to be temperature dependent and graded in the thickness direction according to the power-law distribution in terms of volume fractions of the constituents. The effective material properties are estimated from the volume fractions and the material properties of the constituents using Mori-Tanaka homogenization method. The nonlinear governing equations obtained using Lagrange's equations of motion are solved using finite element procedure coupled with the direct iteration technique. The variation of nonlinear frequency ratio with amplitude is highlighted considering various parameters such as gradient index, temperature, thickness and aspect ratios, and skew angle. For...

  7. OPTIMAL DESIGN OF QUADRATIC SANDWICH PLATE

    Directory of Open Access Journals (Sweden)

    TIMAR Dr. Imre

    2016-05-01

    Full Text Available In this paper, we show the optimal design of the three-layered sandwich plates. The objective function contains the material and fabrication costs. The design constraints are the maximal stresses, the deflection of plates and damping of vibrations. The unknown is the thickness of the filling foam. By the mathematical method, we define the minima of the cost function and the optimal thickness of the filling layer of foam. The active constraint is the deflection, so we calculate of the costs of the sandwich plate with the homogeneous plate.

  8. Three-Dimensional Elasticity Solutions for Sound Radiation of Functionally Graded Materials Plates considering State Space Method

    Directory of Open Access Journals (Sweden)

    Tieliang Yang

    2016-01-01

    Full Text Available This paper presents an analytical study for sound radiation of functionally graded materials (FGM plate based on the three-dimensional theory of elasticity. The FGM plate is a mixture of metal and ceramic, and its material properties are assumed to have smooth and continuous variation in the thickness direction according to a power-law distribution in terms of volume fractions of the constituents. Based on the three-dimensional theory of elasticity and state space method, the governing equations with variable coefficients of the FGM plate are derived. The sound radiation of the vibration plate is calculated with Rayleigh integral. Comparisons of the present results with those of solutions in the available literature are made and good agreements are achieved. Finally, some parametric studies are carried out to investigate the sound radiation properties of FGM plates.

  9. Bending and vibration of functionally graded material sandwich plates using an accurate theory

    CERN Document Server

    Natarajan, S

    2012-01-01

    In this paper, the bending and the free flexural vibration behaviour of sandwich functionally graded material (FGM) plates are investigated using QUAD-8 shear flexible element developed based on higher order structural theory. This theory accounts for the realistic variation of the displacements through the thickness. The governing equations obtained here are solved for static analysis considering two types of sandwich FGM plates, viz., homogeneous face sheets with FGM core and FGM face sheets with homogeneous hard core. The in-plane and rotary inertia terms are considered for vibration studies. The accuracy of the present formulation is tested considering the problems for which three-dimensional elasticity solutions are available. A detailed numerical study is carried out based on various higher-order models to examine the influence of the gradient index and the plate aspect ratio on the global/local response of different sandwich FGM plates.

  10. Unsteady Unidirectional Flow of Voigt Fluid through the Parallel Microgap Plates with Wall Slip and Given Inlet Volume Flow Rate Variations

    OpenAIRE

    Yinwei Lin; Chen, C. K.

    2015-01-01

    In order to solve the velocity profile and pressure gradient of the unsteady unidirectional slip flow of Voigt fluid, Laplace transform method is adopted in this research. Between the parallel microgap plates, the flow motion is induced by a prescribed arbitrary inlet volume flow rate which varies with time. The velocity slip condition on the wall and the flow conditions are known. In this paper, two basic flow situations are solved, which are a suddenly started and a constant acc...

  11. Three-Dimensional Stress and Stress Intensity for Tensioned Flat Plates with Edge Cracks

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The stress in the thickness direction is an important factor influencing the fracture behavior of structural members. A stress бy tensioned flat plate with edge cracks is widely used as an analysis model. The stresses бx and бy for the plate model can be acquired from Neuber's solution. However, the solution is applicable only for a perfect plane stress or plane strain state. As a consequence of the thickness of the plate a three-dimensional (3-D) stress state will arise near the crack tip, resulting in a variation of the distribution of бx and бy stresses. A full analysis for the 3-D stress fields for a tensioned flat plate with edge cracks has been therefore carried out. The results show that the 3-D stress field near the crack tip is mainly determined by two factors: the thickness of the plate and the curvature radius at the crack tip. A further analysis has been carried out for the stress intensity near the crack tip. In this paper we give some equations matching to the 3-D stress and stress intensity, which describe precisely the stress state near the crack tip, and which can be applied effectively in engineering analysis.

  12. Flexure of the Indian plate and intraplate earthquakes

    Indian Academy of Sciences (India)

    Roger Bilham; Rebecca Bendick; Kali Wallace

    2003-09-01

    The flexural bulge in central India resulting from India's collision with Tibet has a wavelength of approximately 670 km. It is manifest topographically and in the free-air gravity anomaly and the geoid. Calculations of the stress distribution within a flexed Indian plate reveal spatial variations throughout the depth of the plate and also a function of distance from the Himalaya. The wave- length (and therefore local gradient) of stress variation is a function of the effective elastic thickness of the plate, estimates of which have been proposed to lie in the range 40-120 km. The imposition of this stress field on the northward moving Indian plate appears fundamental to explaining the current distribution of intraplate earthquakes and their mechanisms. The current study highlights an outer trough south of the flexural bulge in central India where surface stresses are double the contiguous compressional stresses to the north and south. The Bhuj, Latur and Koyna earthquakes and numerous other recent reverse faulting events occurred in this compressional setting. The N/S spatial gradient of stress exceeds 2 bars/km near the flexural bulge. The overall flexural stress distribution provides a physical basis for earthquake hazard mapping and suggests that areas of central India where no historic earthquakes are recorded may yet be the locus of future damaging events.

  13. Green roof seasonal variation: comparison of the hydrologic behavior of a thick and a thin extensive system in New York City

    Science.gov (United States)

    Elliott, R. M.; Gibson, R. A.; Carson, T. B.; Marasco, D. E.; Culligan, P. J.; McGillis, W. R.

    2016-07-01

    Green roofs have been utilized for urban stormwater management due to their ability to capture rainwater locally. Studies of the most common type, extensive green roofs, have demonstrated that green roofs can retain significant amounts of stormwater, but have also shown variation in seasonal performance. The purpose of this study is to determine how time of year impacts the hydrologic performance of extensive green roofs considering the covariates of antecedent dry weather period (ADWP), potential evapotranspiration (ET0) and storm event size. To do this, nearly four years of monitoring data from two full-scale extensive green roofs (with differing substrate depths of 100 mm and 31 mm) are analyzed. The annual performance is then modeled using a common empirical relationship between rainfall and green roof runoff, with the addition of Julian day in one approach, ET0 in another, and both ADWP and ET0 in a third approach. Together the monitoring and modeling results confirm that stormwater retention is highest in warmer months, the green roofs retain more rainfall with longer ADWPs, and the seasonal variations in behavior are more pronounced for the roof with the thinner media than the roof with the deeper media. Overall, the ability of seasonal accounting to improve stormwater retention modeling is demonstrated; modification of the empirical model to include ADWP, and ET0 improves the model R 2 from 0.944 to 0.975 for the thinner roof, and from 0.866 to 0.870 for the deeper roof. Furthermore, estimating the runoff with the empirical approach was shown to be more accurate then using a water balance model, with model R 2 of 0.944 and 0.866 compared to 0.975 and 0.866 for the thinner and deeper roof, respectively. This finding is attributed to the difficulty of accurately parameterizing the water balance model.

  14. Newtonian Equal Thickness Straight Lines Interference and Its Variation Structure%牛顿型等厚直纹干涉及其变异结构

    Institute of Scientific and Technical Information of China (English)

    周国全

    2015-01-01

    采用分类归纳的方法给出各类变异的牛顿型等厚直纹干涉结构,推导并分析了各类干涉结构发生等厚干涉的条件及干涉条纹的分布规律。理论推导与实验结果相互印证。同时指明牛顿型直纹干涉技术在圆柱形工件表面曲率半径的测定方面的应用,特别是非接触式牛顿型直纹干涉结构在某些圆柱形及平板形工件表面缺陷与畸变的无损探测方面的应用,以及应用于牛顿环光学干涉技术的教学研究。%Some new variant structures of interference apparatus with Newton type equal thickness straight fringes are studied and discussed ,the interference condition and distribution law of their interference fringes are analysed .Their novelty and equal effectiveness in the interference principle compared to the original interferometer for Newton′s rings are thrown light on .We find that the subtraction of squared distances of any two adjacent straight fringes to the central fringe acquired in this interference apparatus are constant ,which is independent of their interference orders ,predict their possible application in teaching and research of equal inteference technique , especially the apparatus of Newton′s rings .

  15. Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.

    Science.gov (United States)

    Mehrkash, Milad; Azhari, Mojtaba; Mirdamadi, Hamid Reza

    2014-01-01

    The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates.

  16. Evidence for fast seismic lid structure beneath the Californian margin and its implication on regional plate deformation

    Science.gov (United States)

    Lai, V. H.; Graves, R. W.; Wei, S.; Helmberger, D. V.

    2015-12-01

    The lithospheric structure of the Pacific and North American plates play an important role in modulating plate deformation along the California margin. Pure path models indicate that the Pacific plate has a fast thick (80km) lid overlaying a strong low velocity zone (LVZ) extending to beyond 300 km depth. In contrast, the North America structure is characterized by a relatively thin (25-35km) lid and a shallow LVZ. Vertical ray paths have similar travel times across the plate boundary for the two models, making resolution of the transitional structure difficult. Earthquakes such as the 2014 March 10 Mw 6.8 Mendocino and 2014 August 25 Mw 6.0 Napa events recorded at regional distances across California provide an opportunity to study horizontal paths and track the lateral variation in the lower crust-uppermost mantle structure under the Californian margin. Observations from both Napa and Mendocino events show direct SH-wave arrivals at Southern California Seismic Network (SCSN) stations are systematically earlier (up to 10 s) for coastal and island stations relative to inland sites. The shift in SH arrival times may be due to features such as varying crustal thickness, varying upper mantle velocity and the presence of a fast seismic lid. To test the different hypotheses, we perform extensive forward modeling using both 1-D frequency-wavenumber and 3-D finite-difference approaches. The model that best fits the SH arrival times has a fast lid (Vs = 4.7 km/s) underlying the whole California margin, with the lid increasing in thickness from east to west to a maximum thickness about 70 km in the western offshore region. The fast, thick seismic lid lends strength and rigidity to the Pacific plate lithosphere in contrast with the weaker North American continental plate, which influences the overall plate deformation along the Californian margin and is in agreement with GPS measurements.

  17. Red shift, blue shift: investigating Doppler shifts, blubber thickness, and migration as explanations of seasonal variation in the tonality of Antarctic blue whale song.

    Science.gov (United States)

    Miller, Brian S; Leaper, Russell; Calderan, Susannah; Gedamke, Jason

    2014-01-01

    The song of Antarctic blue whales (Balaenoptera musculus intermedia) comprises repeated, stereotyped, low-frequency calls. Measurements of these calls from recordings spanning many years have revealed a long-term linear decline as well as an intra-annual pattern in tonal frequency. While a number of hypotheses for this long-term decline have been investigated, including changes in population structure, changes in the physical environment, and changes in the behaviour of the whales, there have been relatively few attempts to explain the intra-annual pattern. An additional hypothesis that has not yet been investigated is that differences in the observed frequency from each call are due to the Doppler effect. The assumptions and implications of the Doppler effect on whale song are investigated using 1) vessel-based acoustic recordings of Antarctic blue whales with simultaneous observation of whale movement and 2) long-term acoustic recordings from both the subtropics and Antarctic. Results from vessel-based recordings of Antarctic blue whales indicate that variation in peak-frequency between calls produced by an individual whale was greater than would be expected by the movement of the whale alone. Furthermore, analysis of intra-annual frequency shift at Antarctic recording stations indicates that the Doppler effect is unlikely to fully explain the observations of intra-annual pattern in the frequency of Antarctic blue whale song. However, data do show cyclical changes in frequency in conjunction with season, thus suggesting that there might be a relationship among tonal frequency, body condition, and migration to and from Antarctic feeding grounds.

  18. Red shift, blue shift: investigating Doppler shifts, blubber thickness, and migration as explanations of seasonal variation in the tonality of Antarctic blue whale song.

    Directory of Open Access Journals (Sweden)

    Brian S Miller

    Full Text Available The song of Antarctic blue whales (Balaenoptera musculus intermedia comprises repeated, stereotyped, low-frequency calls. Measurements of these calls from recordings spanning many years have revealed a long-term linear decline as well as an intra-annual pattern in tonal frequency. While a number of hypotheses for this long-term decline have been investigated, including changes in population structure, changes in the physical environment, and changes in the behaviour of the whales, there have been relatively few attempts to explain the intra-annual pattern. An additional hypothesis that has not yet been investigated is that differences in the observed frequency from each call are due to the Doppler effect. The assumptions and implications of the Doppler effect on whale song are investigated using 1 vessel-based acoustic recordings of Antarctic blue whales with simultaneous observation of whale movement and 2 long-term acoustic recordings from both the subtropics and Antarctic. Results from vessel-based recordings of Antarctic blue whales indicate that variation in peak-frequency between calls produced by an individual whale was greater than would be expected by the movement of the whale alone. Furthermore, analysis of intra-annual frequency shift at Antarctic recording stations indicates that the Doppler effect is unlikely to fully explain the observations of intra-annual pattern in the frequency of Antarctic blue whale song. However, data do show cyclical changes in frequency in conjunction with season, thus suggesting that there might be a relationship among tonal frequency, body condition, and migration to and from Antarctic feeding grounds.

  19. MeltMigrator: A MATLAB-based software for modeling three-dimensional melt migration and crustal thickness variations at mid-ocean ridges following a rules-based approach

    Science.gov (United States)

    Bai, Hailong; Montési, Laurent G. J.; Behn, Mark D.

    2017-01-01

    MeltMigrator is a MATLAB®-based melt migration software developed to process three-dimensional mantle temperature and velocity data from user-supplied numerical models of mid-ocean ridges, calculate melt production and melt migration trajectories in the mantle, estimate melt flux along plate boundaries, and predict crustal thickness distribution on the seafloor. MeltMigrator is also capable of calculating compositional evolution depending on the choice of petrologic melting model. Programmed in modules, MeltMigrator is highly customizable and can be expanded to a wide range of applications. We have applied it to complex mid-ocean ridge model settings, including transform faults, oblique segments, ridge migration, asymmetrical spreading, background mantle flow, and ridge-plume interaction. In this technical report, we include an example application to a segmented mid-ocean ridge. MeltMigrator is available as a supplement to this paper, and it is also available from GitHub and the University of Maryland Geodynamics Group website.

  20. Interplate coupling at oblique subduction zones: influence on upper plate erosion.

    Science.gov (United States)

    Malatesta, Cristina; Gerya, Taras; Crispini, Laura; Federico, Laura; Scambelluri, Marco; Capponi, Giovanni

    2014-05-01

    the sedimentary infill of the trench is almost nonexistent, short-term shallow coupling occurs and friction between the frontal sector of the overriding plate and the downgoing plate triggers upper-plate bending. In this sector, after the early short-term coupling, the overriding plate is hereafter decoupled from the subducting slab. Moving along trench-strike, where sediments amount increases, the upper plate couples with the subducting plate and is dragged coherently downwards. If a large amount of sediments is stored in the trench the overriding plate is scraped off and incorporated as fragments along the plate interface. Our results suggest that a) one main parameter controlling coupling at convergent plate margins is the occurrence and the amount of sediment at the trench; b) the upper plate margin is dragged to depth or destroyed only where sediments thickness at the trench is large enough to promote interplate coupling, suggesting that a variation of sediment amount along the trench-axis influences the amount and style of transport of upper-plate material in the mantle.

  1. Trapped modes in 3D topographically varying plates

    Science.gov (United States)

    Postnova, J.; Craster, R. V.

    2008-12-01

    Trapped modes in 3D elastic plates are considered as a model of waves that are guided along, and localized to the vicinity of, welds. These waves propagate unattenuated along the weld and exponentially decay with distance transverse to it. In the direction of propagation (y), there is no change in geometry and we assume that waves have the form exp(i{beta}y). An asymptotic long-wave theory provides numerical values of the trapped mode frequencies and gives conditions at which trapping can occur; these depend on the components of the wave number in different directions and variations of the plate thickness. The results of this long-wave theory are compared with a numerical solution of the full governing equations.

  2. Evaluation of korzincalloy prepared by Hohman Plating

    Energy Technology Data Exchange (ETDEWEB)

    Korinko, P. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hollingshad, A. N. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-07-17

    A commercial vendor, Hohman Plating performed contract engineering work to determine the feasibility of producing pin hole free KorZincAlloy bronze material used for zinc gettering. Samples were tested for Sn plating thickness, heat treatability, and chemistry prior to being subjected to a standardized zinc exposure. The samples absorbed zinc and were examined using visual and scanning electron microscopy. Hohman Plating successfully produced KZA that met the target composition, was pin hole free, and was an effective zinc getter.

  3. Earthquake depth-energy release: thermomechanical implications for dynamic plate theory

    CERN Document Server

    Patton, Regan L

    2012-01-01

    Analysis of the global centroid-moment tensor catalog reveals significant regional variations of seismic energy release to 290 km depth. These variations reflect radial and lateral contrasts in thermomechanical competence, consistent with a shear-dominated non-adiabatic boundary layer some 700-km thick, capped by denser oceanic lithosphere as much as 100 km thick, or lighter continental tectosphere 170 to 260 km thick. Thus, isobaric shearing at fractally-distributed depths likely facilitates toroidal plate rotations while minimizing global energy dissipation. Shear localization in the shallow crust occurs as dislocations at finite angles with respect to the shortening direction, with a 30 degree angle being the most likely. Consequently, relatively low-angle reverse faults, steep normal faults, and triple junctions with orthogonal or hexagonal symmetry are likely to form in regions of crustal shortening, extension, and transverse motion, respectively. Thermomechanical theory also predicts adiabatic condition...

  4. 高韧性抗层状撕裂钢板 Q345FTE - Z35的开发%Development of Q345FTE - Z35 Steel Plate with High Toughness and Through - Thickness Property

    Institute of Scientific and Technical Information of China (English)

    向华; 秦军; 刘奉家; 胡小伟

    2015-01-01

    通过 Nb、V、Ti、Cu、Ni 复合微合金化的成分设计,采用两阶段控制轧制生产工艺,八钢成功开发出风塔用 Q345FTE - Z35钢板,在保证钢板强韧性的同时,获得了良好的抗层状撕裂性能,各项性能指标均满足国家标准要求。%By means of chemical composition design of Nb,V、Ti、Cu、Ni composite microalloying and II Phase controlled rolling process,Bayi Iron and Steel Co. has successfully developed Q345FTE - Z35 steel plate for wind power tower,of which sufficient strength and toughness,good lamellar resistance are maintained with all properties items satis-fying the requirements of national standards.

  5. Simulation of multi-pass welding residual stress in thick plate based on ANSYS%基于ANSYS的厚板多道焊焊接残余应力模拟

    Institute of Scientific and Technical Information of China (English)

    张晓飞

    2012-01-01

    利用ANSYS参数化有限元分析APDL语言编制相关程序,对980钢平板对接焊的温度场及应力场进行模拟,为实际生产过程中分析焊接结构性能、优化焊接工艺提供了有效指导.%In this paper, using the ANSYS parametric finite element analysis of APDL language procedures, simulates the butt-welding thermal field and stress field on 980 sleel plate,as the actual production process analysis of welding structure properties, optimizing welding technology provides effective guidance.

  6. Thin plate neotectonic models of the Australian plate

    Science.gov (United States)

    Burbidge, D. R.

    2004-10-01

    Thin plate finite element models of the neotectonic deformation of the Australian plate have been calculated in order to estimate the stress and strain rate within the plate, specifically concentrating on the Australian continent. The model includes plate-bounding faults, an anelastic brittle-ductile layered rheology and the option of laterally varying elevation and heat flow. The results of the models are compared to (1) the velocity of geodetic benchmarks on the Australian plate, (2) the spreading rate of the mid-oceanic ridges along the Australian plate's margins, (3) the direction of the maximum horizontal principal stress, (4) the stress regime within the plate, and (5) the crustal thickness estimated from the depth to the base of Mohorovicic discontinuity's transition zone. A variety of models are tested with a wide range of input parameters. The model with the smallest misfit with observations predicts that the strain rate for most of the Australian continent is approximately 10-17 s-1. This model has a slightly lower strain rate in the central Australia and is higher off the northern coast of Australia than for the rest of the continent. Strain rates of this magnitude would be difficult to observe from geodetic or geologic data for most parts of Australia but would be enough to generate much of the seismicity that has been observed over the last century.

  7. Magma production rate along the Ninetyeast Ridge and its relationship to Indian plate motion and Kerguelen hot spot activity

    Science.gov (United States)

    Sreejith, K. M.; Krishna, K. S.

    2015-02-01

    The Ninetyeast Ridge, a linear trace of the Kerguelen hot spot in the Indian Ocean, was emplaced on a rapidly drifting Indian plate. Magma production rates along the ridge track are computed using gravity-derived excess crustal thickness data. The production rates change between 2 and 15 m3/s over timescales of 3-16 Myr. Major variations in magma production rates are primarily associated with significant changes in the Indian plate velocity with low-production phases linked to high plate velocity periods. The lowest magma production rate (2 m3/s) at 62 Ma is associated with the rapid northward drift of Indian plate under the influence of the Reunion mantle plume. The contemporaneous slowing of the African plate coincides with increase in magma production rate along the Walvis Ridge in the Atlantic Ocean. The present study suggests that variations in the Indian plate motion and frequent ridge jumps have a major role in controlling the magma production, particularly on long-period cycles (~16 Myr). Short-period variations (~5 Myr) in magma productions may be associated with intrinsic changes in the plume, possibly due to the presence of solitary waves in the plume conduit.

  8. FLEXURAL WAVE PROPAGATION IN NARROW MINDLIN'S PLATE

    Institute of Scientific and Technical Information of China (English)

    HU Chao; HAN Gang; FANG Xue-qian; HUANG Wen-hu

    2006-01-01

    Appling Mindlin's theory of thick plates and Hamilton system to propagation of elastic waves under free boundary condition, a solution of the problem was given.Dispersion equations of propagation mode of strip plates were deduced from eigenfunction expansion method. It was compared with the dispersion relation that was gained through solution of thick plate theory proposed by Mindlin. Based on the two kinds of theories,the dispersion curves show great difference in the region of short waves, and the cutoff frequencies are higher in Hamiltonian systems. However, the dispersion curves are almost the same in the region of long waves.

  9. Idealization of a Gas Turbine Compressor Blade to a Rectangular Plate and Analyzing the Variation of Stress Concentration Factor for U-Notches

    Directory of Open Access Journals (Sweden)

    Mohammad Rafi Nadaf

    2014-01-01

    Full Text Available Aircraft turbine engines routinely experience the ingestion of debris resulting in "foreign object damage‟ FOD. The ingestion of foreign object into aircraft engines leads to severe structural damage of the fan or compressor blades. Foreign object damage by hard particles mostly occurs during motion of the aircraft on the airfield, during take-off and during landing. Typical objects ingested are stones and other debris; sizes in the millimeter regime form the airfield. The worst case condition is experienced during take-off maximum thrusts leads to maximum impact velocity. Typical impact velocities are in the regime of 100 – 400m/sec, depending on the types of engine and impact location on the blades. Foreign object damage does not always lead to sudden catastrophic failure, yet such damage can have a detrimental effect on the fatigue strength of fan and compressor aero foils. However complex stress fields and geometry of the aerofoil make it difficult to use of simple notch analysis. For finding the stress concentration factor on the notches grinded on the typical aerofoil FOD damaged gas turbine compressor blade closed form solutions are difficult proportion. In this paper a finite element analysis is carried out by idealization of the typical aerofoil to rectangular cantilever plate with single edge U-notches for finding the stress concentration factor and is then compared with the standard stress concentration data by R.E.Peterson. The study can then be extended to a typical aerofoil.

  10. Notched Strength of Woven Fabric Kenaf Composite Plates with Different Stacking Sequences and Hole Sizes

    Directory of Open Access Journals (Sweden)

    Hans Romayne Anders

    2016-01-01

    Full Text Available Advantages of using kenaf fibres over synthetic fibres in composites manufacturing are relatively cheap, less abrasive and hazardous during handling, and renewable materials. Current work investigates parametric effects on notched strength of woven fabric kenaf polymer composites plates with variation of lay-up types, notch sizes and plate thickness. Testing coupons are prepared using hand lay-up technique and circular notch were drilled prior to mechanical testing. Stress concentration at the notch edge promotes micro-damage event as tensile loading was applied leading to crack initiation and propagations across the plate width. It is suggested that woven fabric kenaf polymer composites are potentially used in low and medium load bearing applications.

  11. Amplification of acoustic waves in laminated piezoelectric semiconductor plates

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.S.; Yang, X.M.; Turner, J.A. [University of Nebraska, Department of Engineering Mechanics, Lincoln, NE (United States)

    2004-12-01

    Two-dimensional equations for coupled extensional, flexural and thickness-shear motions of laminated plates of piezoelectric semiconductors are obtained systematically from the three-dimensional equations by retaining lower order terms in power series expansions in the plate thickness coordinate. The equations are used to analyze extensional waves in a composite plate of piezoelectric ceramics and semiconductors. Dispersion and dissipation due to semiconduction as well as wave amplification by a dc electric field are discussed. (orig.)

  12. Create Your Plate

    Medline Plus

    Full Text Available ... A A A Listen En Español Create Your Plate Create Your Plate is a simple and effective ... and that your options are endless. Create Your Plate! Click on the plate sections below to add ...

  13. Edge wrinkling in elastically supported pre-stressed incompressible isotropic plates

    Science.gov (United States)

    Destrade, Michel; Fu, Yibin; Nobili, Andrea

    2016-09-01

    The equations governing the appearance of flexural static perturbations at the edge of a semi-infinite thin elastic isotropic plate, subjected to a state of homogeneous bi-axial pre-stress, are derived and solved. The plate is incompressible and supported by a Winkler elastic foundation with, possibly, wavenumber dependence. Small perturbations superposed onto the homogeneous state of pre-stress, within the three-dimensional elasticity theory, are considered. A series expansion of the plate kinematics in the plate thickness provides a consistent expression for the second variation of the potential energy, whose minimization gives the plate governing equations. Consistency considerations supplement a constraint on the scaling of the pre-stress so that the classical Kirchhoff-Love linear theory of pre-stretched elastic plates is retrieved. Moreover, a scaling constraint for the foundation stiffness is also introduced. Edge wrinkling is investigated and compared with body wrinkling. We find that the former always precedes the latter in a state of uni-axial pre-stretch, regardless of the foundation stiffness. By contrast, a general bi-axial pre-stretch state may favour body wrinkling for moderate foundation stiffness. Wavenumber dependence significantly alters the predicted behaviour. The results may be especially relevant to modelling soft biological materials, such as skin or tissues, or stretchable organic thin-films, embedded in a compliant elastic matrix.

  14. Development of bipolar plates with different flow channel configurations for fuel cells

    Science.gov (United States)

    Boddu, Rajesh; Marupakula, Uday Kumar; Summers, Benjamin; Majumdar, Pradip

    Bipolar plates include separate gas flow channels for anode and cathode electrodes of a fuel cell. These gases flow channels supply reactant gasses as well as remove products from the cathode side of the fuel cell. Fluid flow, heat and mass transport processes in these channels have significant effect on fuel cell performance, particularly to the mass transport losses. The design of the bipolar plates should minimize plate thickness for low volume and mass. Additionally, contact faces should provide a high degree of surface uniformity for low thermal and electrical contact resistances. Finally, the flow fields should provide for efficient heat and mass transport processes with reduced pressure drops. In this study, bipolar plates with different serpentine flow channel configurations are analyzed using computational fluid dynamics modeling. Flow characteristics including variation of pressure in the flow channel across the bipolar plate are presented. Pressure drop characteristics for different flow channel designs are compared. Results show that with increased number of parallel channels and smaller sizes, a more effective contact surface area along with decreased pressured drop can be achieved. Correlations of such entrance region coefficients will be useful for the PEM fuel cell simulation model to evaluate the affects of the bipolar plate design on mass transfer loss and hence on the total current and power density of the fuel cell.

  15. Surface modification of the patterned Al6061/SUS304 metal plates using the large electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Min; Kim, Jisu; Park, Sung Soo [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of); Park, Hyung Wook, E-mail: hwpark@unist.ac.kr [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of); Ki, Hyungson [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer We performed the large-electron-beam polishing of the patterned metal plates. Black-Right-Pointing-Pointer We observed its effect on surface hardness, surface roughness, and water repellency. Black-Right-Pointing-Pointer The contact angle for Al6061 and SUS304 increased after the electron-beam irradiation. Black-Right-Pointing-Pointer We observed the microstructure after the electron beam irradiation. - Abstract: Polishing is a finishing process used to improve surface integrity by reducing surface roughness and residual stress caused by other machining processes. The recently developed electron beam polishing method was used in this study to improve surface quality. In this process, an electron beam with a maximum diameter of 60 mm was applied for a few microseconds to melt and evaporate a metal surface. Al6061 and SUS304 metal plates were prepared with different geometric patterns and subjected to electron beam polishing. The surface roughness of the patterned SUS304 metal plate was significantly improved. However, the surface roughness of the patterned Al6061 metal plate became worse. Although the surface hardness decreased by approximately 10% on the re-solidified layers on both types of plates, the contact angle increased due to changes in surface morphology. The microstructure variation after the electron beam irradiation was also examined and compared with the thickness prediction of the re-solidified layer for Al6061 and SUS304 metal plates.

  16. An Analytical Approach on Thermally Induced Vibrations of Nonhomogeneous Tapered Plate

    Directory of Open Access Journals (Sweden)

    Anupam Khanna

    2013-01-01

    Full Text Available A mathematical model to control the vibrations of a rectangular plate is constructed with an aim to assist engineers in designing and fabrication of various structures used in the field of science and technology, mostly used in satellite and aeronautical engineering. The present study is related to the analysis of free vibrations of nonhomogeneous rectangular plate clamped at all the four edges. Authors studied the bilinear effect of thickness as well as temperature variations in both and directions. Variation in Poisson's ratio is also considered linearly in -direction due to nonhomogeneity. Rayleigh-Ritz method is used to analyze the frequencies for the first two modes of vibrations for different values of thermal gradient, nonhomogeneity constant, taper constants and aspect ratio. All the numerical computations have been performed for an alloy of aluminum, that is, duralumin. All the results are presented in the form of graphs.

  17. Elastic buckling strength of corroded steel plates

    Indian Academy of Sciences (India)

    Ahmad Rahbar-Ranji

    2013-02-01

    Corrosion makes structures more vulnerable to buckling and yielding failures. It is common practice to assume a uniform thickness reduction for general corrosion. To estimate the remaining strength of corroded structures, typically a much higher level of accuracy is required, since the actual corroded structures have irregular surfaces. Elastic buckling of simply supported rectangular corroded plates are studied with one- and both-sided irregular surfaces. Eigenvalue analysis by using finite element method (FEM) is employed for computing Euler stress. The influence of various geometric and corrosion characteristics are investigated and it is found that the aspect ratio of the plate, the average thickness diminution, the standard deviation of thickness diminution and the amount of corrosion loss have influence on the reduction of buckling strength of the corroded plates. Buckling strength of one- and both-sided corroded plates are the same. In plates with low value of aspect ratio, reduction of buckling strength is negligible. Reduction of buckling strength is more prominent in plates with higher aspect ratio. Reduction of buckling strength is very sensitive to the amount of corrosion loss; the higher the amount of corrosion loss, the more reduction of buckling strength. Reduction of buckling strength is less sensitive to the standard deviation of thickness diminution.

  18. Accuracy of MRI in Growth Plate Measurement

    DEFF Research Database (Denmark)

    Shiguetomi Medina, Juan Manuel; Rahbek, Ole; Ringgaard, Steffen

    2013-01-01

    Objective. Analysis of the accuracy of growth plate thickness measurements detected on 1.5T and 7T MR images using histology sections as gold standard. Materials and Methods. Four defrosted pig tibiae were 1.5T MR scanned and one fresh tibia was 7T MR scanned. The height of the growth plate...... was measured and compared to histology. Results. Histology measurements showed a mean growth plate thickness of 467 μm (SD = 82.2). The mean growth plate thickness measured in the 7T MR images was 465 μm (SD = 62.2) and 1325 μm (SD=183.5) on 1.5 MRI measurements. We found a better correlation between...... the growth plate thickness measured on the 7T MRI and histology samples compared to 1.5T, where the accuracy was poor. Conclusion. The growth plate can be identified and measured with high accuracy using 7T MRI. 1.5T MRI can only describe some morphological characteristics; its poor resolution impedes to do...

  19. Accuracy of MRI in Growth Plate Measurement

    DEFF Research Database (Denmark)

    Shiguetomi Medina, Juan Manuel; Rahbek, Ole; Ringgaard, Steffen

    2013-01-01

    Objective. Analysis of the accuracy of growth plate thickness measurements detected on 1.5T and 7T MR images using histology sections as gold standard. Materials and Methods. Four defrosted pig tibiae were 1.5T MR scanned and one fresh tibia was 7T MR scanned. The height of the growth plate...... was measured and compared to histology. Results. Histology measurements showed a mean growth plate thickness of 467 μm (SD = 82.2). The mean growth plate thickness measured in the 7T MR images was 465 μm (SD = 62.2) and 1325 μm (SD=183.5) on 1.5 MRI measurements. We found a better correlation between...... the growth plate thickness measured on the 7T MRI and histology samples compared to 1.5T, where the accuracy was poor. Conclusion. The growth plate can be identified and measured with high accuracy using 7T MRI. 1.5T MRI can only describe some morphological characteristics; its poor resolution impedes to do...

  20. Accuracy of MR in growth plate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Shiguetomi-Medina, Juan Manuel [Aarhus University, Orthopaedic Research Laboratory, Aarhus University Hospital NBG, Aarhus C (Denmark); Rahbek, Ole [Aarhus University Hospital NBG, Department of Children' s Orthopaedics, Aarhus C (Denmark); Ringgaard, Steffen; Kristiansen, Maja Sofie; Stoedkilde-Joergensen, Hans [Aarhus University Hospital, Skejby, The MR Research Center, Aarhus N (Denmark); Moeller-Madsen, Bjarne [Aarhus University, Orthopaedic Research Laboratory, Aarhus University Hospital NBG, Aarhus C (Denmark); Aarhus University Hospital NBG, Department of Children' s Orthopaedics, Aarhus C (Denmark)

    2014-09-15

    To analyze the accuracy of growth-plate thickness measurements detected on 1.5-T and 7-T MR images using histology sections as a standard of reference. Four defrosted pig tibiae were 1.5-T MR scanned and one fresh tibia was 7-T MR scanned. The height of the growth plate was measured and compared to histology. Histology measurements showed a mean growth plate thickness of 467 μm (SD = 82.2). The mean growth plate thickness measured in the 7-T MR images was 465 μm (SD = 62.2) and 1,325 μm (SD = 183.5) on 1.5-T MR measurements. We found a better correspondence between the growth plate thickness measured on the 7-T MR and histology samples compared to 1.5 T. The growth plate can be identified and measured with high accuracy using 7-T MR. 1.5-T MR can only describe some morphological characteristics. (orig.)

  1. Transmitted and Reflected Coefficients for Horizontal or Vertical Plate Type Breakwater

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; ZHANG Zhi-qiang; XU Wang

    2011-01-01

    Surface or submerged horizontal or vertical plate can be considered as a new concept breakwater. This paper investigates the wave-plate interaction of this type of breakwater by use of the boundary element method. The relationships of wave transmitted and reflected among plate thickness, submergence and length are carefully studied by numerical simulation. It is shown that: (1) The transmitted coefficients of submerged horizontal plate or vertical plate will become larger with the increase of plate thickness and reduce rapidly with the decrease of plate submergence. (2) Both surface horizontal and vertical plate are efficient for intermediate and short wave elimination, but vertical plate is more effective. (3)Submerged horizontal plate can act more effectively than submerged vertical plate does. With all wave frequencies, the vertical plate almost has no wave elimination effect.

  2. Peripapillary choroidal thickness in childhood.

    Science.gov (United States)

    Read, Scott A; Alonso-Caneiro, David; Vincent, Stephen J; Collins, Michael J

    2015-06-01

    Changes in the thickness of the invivo peripapillary choroid have been documented in a range of ocular conditions in adults; however, choroidal thickness in the peripapillary region of children has not been examined in detail. This study therefore aimed to investigate the thickness of the peripapillary choroid and the overlying retinal nerve fibre layer (RNFL) in a population of normal children with a range of refractive errors. Ninety-three children (37 myopes and 56 non-myopes) aged between 11 and 16 years, had measurements of peripapillary choroidal and RNFL thickness derived from enhanced depth imaging optical coherence tomography images (EDI-OCT, Heidelberg Spectralis). The average thickness was determined in a series of five 0.25 mm width concentric annuli (each divided into 8 equal sized 45° sectors) centred on the optic nerve head boundary, accounting for individual ocular magnification factors and the disc-fovea angle. Significant variations in peripapillary choroidal thickness were found to occur with both annulus location (p choroid (mean 77 ± 16 μm) and the outermost annulus, the thickest choroid (191 ± 52 μm). The choroid was thinnest inferior to the optic nerve head (139 ± 38 μm) and was thickest in the superior temporal sector (157 ± 40 μm). Significant differences in the distribution of choroidal thickness were also associated with myopia, with myopic children having significantly thinner choroids in the inner and outer annuli of the nasal and temporal sectors respectively (p thickness also varied significantly with annulus location and sector (p thickness distribution associated with refractive error. This study establishes the normal variations in the thickness of the peripapillary choroid with radial distance and azimuthal angle from the optic nerve head boundary. A significant thinning of the peripapillary choroid associated with myopia in childhood was also observed in both nasal and temporal regions. The changes in peripapillary RNFL

  3. Dynamic Behaviors of Axially Moving Viscoelastic Plate with Varying Thicknessn

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yinfeng; WANG Zhongmin

    2009-01-01

    Structural components of varying thickness draw increasing attention these days due to economy and light-weight considerations. In view of the absence of research in vibration analysis of viscoelastic plate with varying thickness, this study devotes to investigate the dynamic behaviors of axially moving viscoelastic plate with varying thickness. Based on the thin plate theory and the two-dimensional viscoelastic differential constitutive relation, the differential equation of motion of the axially moving viscoelastic rectangular plate is derived, the plate constituted by Kelvin-Voigt model has linearly varying thickness in the y-direction. The dimensionless complex frequencies of axially moving viscoelastic plate with four edges simply supported are calculated by the differential quadrature method, curves of real parts and imaginary parts of the first three-order dimensionless complex frequencies versus dimensionless moving speed are obtained, the effects of the aspect ratio, thickness ratio, the dimensionless moving speed and delay time on the dynamic behaviors of the axially moving viscoelastic rectangular plate with varying thickness are analyzed. When other parameters keep constant, with the decrease of thickness ratio, the real parts of the first three-order natural frequencies decrease, and the critical divergence speeds of various modes decrease too, moreover, whether the delay time is large or small, the frequencies are all complex numbers.

  4. High precision refractometry based on Fresnel diffraction from phase plates.

    Science.gov (United States)

    Tavassoly, M Taghi; Naraghi, Roxana Rezvani; Nahal, Arashmid; Hassani, Khosrow

    2012-05-01

    When a transparent plane-parallel plate is illuminated at a boundary region by a monochromatic parallel beam of light, Fresnel diffraction occurs because of the abrupt change in phase imposed by the finite change in refractive index at the plate boundary. The visibility of the diffraction fringes varies periodically with changes in incident angle. The visibility period depends on the plate thickness and the refractive indices of the plate and the surrounding medium. Plotting the phase change versus incident angle or counting the visibility repetition in an incident-angle interval provides, for a given plate thickness, the refractive index of the plate very accurately. It is shown here that the refractive index of a plate can be determined without knowing the plate thickness. Therefore, the technique can be utilized for measuring plate thickness with high precision. In addition, by installing a plate with known refractive index in a rectangular cell filled with a liquid and following the described procedures, the refractive index of the liquid is obtained. The technique is applied to measure the refractive indices of a glass slide, distilled water, and ethanol. The potential and merits of the technique are also discussed.

  5. Plastic collapse load of corroded steel plates

    Indian Academy of Sciences (India)

    Rahbar Ranji Ahmad

    2012-06-01

    Corrosion is one of the detrimental phenomena which reduces strength of structures. It is common practice to assume a uniform thickness reduction for general corrosion. Since the actual corroded plate has rough surfaces, to estimate the remaining strength of corroded structures, typically a much higher level of accuracy is required. The main aim of present work is to study plastic collapse load of corroded steel plates with irregular surfaces under tension. Non-linear finite element method by using computer code ANSYS was employed to determine plastic collapse load. By comparing the results with uniform thickness assumption, a reduction factor was proposed. It is found that by uniform thickness assumption, plastic collapse load of corroded plates are overestimated.

  6. Influence of deposition parameters on the microstructure of ion-plated films

    Science.gov (United States)

    Broitman, Esteban; Zimmerman, Rosa

    1996-07-01

    Ion plating is essentially vapor deposition onto a substrate which is the cathode of a glow discharge. The most important characteristic of the technique is that the growing film is subjected to a flux of high energy particles (neutrals and ions). In this study we report information about the effect of ion plating parameters on grain diameter and crystallite size distribution. At a constant potential grain size remains constant with the increase of ion density. On the other hand, at a constant ion density the grain size decreases with the substrate potential increment. Ion bombardment also has an effect on the crystallite size distribution. The ion plated films show a higher degree of uniformity in grain size than vacuum evaporated films. In contrast with vacuum evaporated films, where the grain size is proportional to the thickness, no variation of grain size with film thickness has been observed for the ion-plated films. Electron diffraction patterns have shown that the orientation remains near random over the entire J and V range studied.

  7. Negative Effect of Disc Thickness Variation on the Performance of Anti-lock Braking System and Its Control Method%制动盘厚薄差对ABS性能的负面影响及控制方法

    Institute of Scientific and Technical Information of China (English)

    张立军; 黄平宇

    2013-01-01

    A nonlinear braking dynamics model for a quarter car is established, which consists of a rigid-ring-based transient tire model and a disc brake model with consideration of disc thickness variation ( DTV). Based on the model and by using MATLAB/Simulink, the negative effects of DTV on the braking performance of ABS system with slip rate threshold control are analyzed, and a set of adaptive control parameters based on the degrees of DTV are proposed on the basis of optimization to suppress the negative effects of DTV. The results indicate that DTV has negative effects on wheel motion, braking performance and braking comfort, while the use of DTV adaptive control parameters though may deteriorate braking comfort, but can effectively improve wheel motion and braking performance.%建立了包含瞬态刚性圈轮胎模型、考虑制动盘厚薄差(DTV)的制动器模型的1/4车非线性制动动力学模型.基于该模型,利用MATLAB/Simulink软件分析了DTV对滑移率门限值控制下ABS制动性能的负面影响,并提出了一套抑制DTV影响的适应性控制参数.结果表明:DTV会对车轮运动状态、制动效能和制动舒适性产生负面影响,而采用DTV适应性ABS控制参数虽会恶化舒适性,但可改善车轮运动状态,提高制动效能.

  8. Horizontal versus vertical plate motions

    Directory of Open Access Journals (Sweden)

    M. Cuffaro

    2006-07-01

    Full Text Available We review both present and past motions at major plate boundaries, which have the horizontal component in average 10 to 100 times faster (10–100 mm/yr than the vertical component (0.01–1 mm/yr in all geodynamic settings. The steady faster horizontal velocity of the lithosphere with respect to the upward or downward velocities at plate boundaries supports dominating tangential forces acting on plates. This suggests a passive role of plate boundaries with respect to far field forces determining the velocity of plates. The forces acting on the lithosphere can be subdivided in coupled and uncoupled, as a function of the shear at the lithosphere base. Higher the asthenosphere viscosity, more significant should be the coupled forces, i.e., the mantle drag and the trench suction. Lower the asthenosphere viscosity, more the effects of uncoupled forces might result determinant, i.e., the ridge push, the slab pull and the tidal drag. Although a combination of all forces acting on the lithosphere is likely, the decoupling between lithosphere and mantle suggests that a torque acts on the lithosphere independently of the mantle drag. Slab pull and ridge push are candidates for generating this torque, but, unlike these boundary forces, the advantage of the tidal drag is to be a volume force, acting simultaneously on the whole plates, and being the decoupling at the lithosphere base controlled by lateral variations in viscosity of the low-velocity layer.

  9. Bending and buckling behavior analysis of foamed metal circular plate.

    Science.gov (United States)

    Fan, Jian Ling; Ma, Lian Sheng; Zhang, Lu; De Su, Hou

    2016-07-04

    This paper establishes a density gradient model along the thickness direction of a circular plate made of foamed material. Based on the first shear deformation plate theory, the result is deduced that the foamed metal circular plate with graded density along thickness direction yields axisymmetric bending problem under the action of uniformly distributed load, and the analytical solution is obtained by solving the governing equation directly. The analyses on two constraint conditions of edge radial clamping and simply supported show that the density gradient index and external load may affect the axisymmetric bending behavior of the plate. Then, based on the classical plate theory, the paper analyzes the behavior of axisymmetric buckling under radial pressure applied on the circular plate. Shooting method is used to obtain the critical load, and the effects of gradient nature of material properties and boundary conditions on the critical load of the plate are analyzed.

  10. Influence of boundary conditions on the response of multilayered plates with cohesive interfaces and delaminations using a homogenized approach

    Directory of Open Access Journals (Sweden)

    R. Massabò

    2014-07-01

    Full Text Available Stress and displacement fields in multilayered composites with interfacial imperfections, such as imperfect bonding of the layers or delaminations, or where the plies are separated by thin interlayers allowing relative motion, have large variations in the thickness, with characteristic zigzag patterns and jumps at the layer interfaces. These effects are well captured by a model recently formulated by the author for multilayered plates with imperfect interfaces and affine interfacial traction laws (Massabò & Campi, Meccanica, 2014, in press; Compos Struct, 2014, 116, 311-324. The model defines a homogenized displacement field, which satisfies interfacial continuity, and uses a variational technique to derive equilibrium equations depending on only six generalized displacement functions, for any arbitrary numbers of layers and interfaces. The model accurately predicts stresses and displacements in simply supported, highly anisotropic, thick plates with continuous, sliding interfaces. In this paper the model is applied to wide plates with clamped edges and some inconsistencies, which have been noted in the literature for models based on similar approaches and have limited their utilization, are explained. A generalized transverse shear force is introduced as the gross stress resultant which is directly related to the bending moment in the equilibrium equations of multilayered structures with imperfect interfaces and substitutes for the shear force of single-layer theory. An application to a delaminated wide plate highlights the potential and limitations of the proposed model for the solution of fracture mechanics problems.

  11. Effect of tempering on fine microstructure of NV-F690 thick steel plate with balanced strength and toughness%回火工艺对高强韧NV-F690厚船板精细组织的影响

    Institute of Scientific and Technical Information of China (English)

    岳重祥; 刘东升

    2012-01-01

    Effect of tempering on fine microstructure of an NV-F690 thick (100 mm) steel plate with balanced strength and toughness for offshore structure and shipbuilding was characterized with SEM, EBSD and TEM, and the relationship between low temperature impact fracture behavior and microstructure of the plate was investigated. The results show that direcf quenched microstructure consist of mainly lath- like bainite (LB) and granular bainite (GB) with coarse martensite/austenite (MA) at ND/2, and LB with narrow laths at ND/4. The impact toughness at ND/2 is lower than that at ND/4. After tempering at 650-690 ℃ for 6 h, profuse Cu precipitation occurs at the tempered plate. Coarse MA constituents decompose, the fraction of high angle grain boundary (HAGB) increases and effective grain size decreases at ND/2, which results in impact toughness improved.%采用SEM、EBSD和TEM研究回火工艺对低C含Cu特厚(100mm)高强韧NV—F690船体和海洋平台用钢板精细组织的影响,深入探讨钢板低温冲击断裂行为与精细组织之间的关系。结果表明,轧后直接淬火态DQ钢板心部(ND/2)组织为板条贝氏体+粒状贝氏体,板条间距较宽,粒状贝氏体中存在较粗大MA组元,低温韧性差;1/4厚度(ND/4)处组织为板条贝氏体,板条间距窄,低温韧性好。650—690℃回火6h后,大量ε-Cu弥散沉淀相在钢板基体组织中析出,钢板ND/2处粗大粒状MA组元分解,大角度晶界分数增加,有效晶粒尺寸减小,低温韧性显著提高。

  12. Classifying Taiwan Lianas with Radiating Plates of Xylem

    Directory of Open Access Journals (Sweden)

    Sheng-Zehn Yang

    2015-12-01

    Full Text Available Radiating plates of xylem are a lianas cambium variation, of which, 22 families have this feature. This study investigates 15 liana species representing nine families with radiating plates of xylem structures. The features of the transverse section and epidermis in fresh liana samples are documented, including shapes and colors of xylem and phloem, ray width and numbers, and skin morphology. Experimental results indicated that the shape of phloem fibers in Ampelopsis brevipedunculata var. hancei is gradually tapered and flame-like, which is in contrast with the other characteristics of this type, including those classified as rays. Both inner and outer cylinders of vascular bundles are found in Piper kwashoense, and the irregularly inner cylinder persists yet gradually diminishes. Red crystals are numerous in the cortex of Celastrus kusanoi. Aristolochia shimadai and A. zollingeriana develop a combination of two cambium variants, radiating plates of xylem and a lobed xylem. The shape of phloem in Stauntonia obovatifoliola is square or truncate, and its rays are numerous. Meanwhile, that of Neoalsomitra integrifolia is blunt and its rays are fewer. As for the features of a stem surface within the same family, Cyclea ochiaiana is brownish in color and has a deep vertical depression with lenticels, Pericampylus glaucus is greenish in color with a vertical shallow depression. Within the same genus, Aristolochia shimadai develops lenticels, which are not in A. zollingeriana; although the periderm developed in Clematis grata is a ring bark and tears easily, that of Clematis tamura is thick and soft.

  13. The effects of possibly buoyant flat slab segments on Nazca and South American plate motions

    Science.gov (United States)

    Lithgow-Bertelloni, C. R.; Shea, R.; Crameri, F.

    2014-12-01

    Flat slabs are ubiquitous today and in Earth's past, present in at least 10% of present-day subduction zones. The Nazca slab is a classic example with large dip variations along strike, including two prominent flat segments in Peru and Argentina that coincide with the subduction of aseismic ridges. The origin of flat segments remain enigmatic though much work has examined the consequences for upper plate deformation and continued subduction. In the case of the Argentinian flat segment, detailed seismic imaging has shown significantly increased crustal thickness in the flat part of the slab. Our present understanding of oceanic crust formation suggests that incrased crustal thickness forms in response to larger degrees of partial melt, which in turn decrease the water content of the formed crust. The residuum from this process is depleted. The resulting combined lithospheric column is buoyant with respect to the underlying mantle, and likely cold from its contact with the overlying plate and unlikely to undergo the basalt-eclogite transition due to kinetic hindrances. This has consequences for mantle flow and the shear stresses it exerts at the base of the lithosphere and hence to plate motions. Interestingly, the motion of the Nazca-South America pair is difficult to reproduce even in the most sophisticated models (Stadler et al. 2010) without invoking special coupling, rheology or forces. We examine the effects of the subduction of neutral and buoyant flat segments on mantle flow and plate motions, globally and locally for Nazca and South America. We construct high-resolution models of the morphology and density structure of the Nazca slab and embed them in an existing global slab model. We compute the global viscous flow induced and predict plate motions consistent with the density heterogeneity and plate geometry. As an end member we also examine a Nazca slab that dips uniformly with a 30 degree dip. We find, perhaps unsurprisingly, that the most important

  14. Enhanced-transmission metamaterials as anisotropic plates

    Science.gov (United States)

    Baida, F. I.; Boutria, M.; Oussaid, R.; van Labeke, D.

    2011-07-01

    We present an original design of anisotropic metamaterial plates exhibiting extraordinary transmission through perfectly conductor metallic screens perforated by a subwavelength double-pattern rectangular aperture array. The polarization properties of the fundamental guided mode inside the apertures are at the origin of the anisotropy. The metal thickness is a key parameter that is adjusted in order to get the desired value of the phase difference between the two transversal electromagnetic field components. As an example, we treat the case of a half-wave plate having 92% transmission coefficient. Such a study can be easily extended to design anisotropic plates operating in terahertz or microwave domains.

  15. High resolution image of the Lithosphere-Asthenosphere Boundary of the subducting Nazca plate beneath northern Chile

    Science.gov (United States)

    Sodoudi, F.; Yuan, X.; Asch, G.; Kind, R.

    2010-12-01

    Results obtained from S and P receiver functions produced a clear image of the top and bottom of the subducting Nazca lithosphere beneath northern Chile. Using data from the teleseismic events recorded at 15 permanent IPOC (Integrated Plate boundary Observatory Chile) stations, we were able to obtain new constraints on the shape and thickness of the descending Nazca lithosphere. We observed the subducted crust of the Nazca plate at depths ranging from 40 km beneath the Coastal Cordillera down to 110 km beneath the Western Cordillera. We found significant along-strike variations in the geometry of the Nazca plate beneath northern Chile. On closer inspection, it appears that the oceanic Nazca plate is divided into two distinct segments as it descends beneath the continental South American plate. The transition from the relatively steeper and deeper slab to the north of 21° S to the flatter southern segment is shown reasonably clearly by our data. This feature could well be associated with variations in the curvature of the plate margin and the geometry of the Chile trench, which is mainly curved to the north of 21° S. We have also mapped the continental Moho of the South American plate at depths ranging between 60-70 km to the east of the Longitudinal Valley. Beneath the Coastal Cordillera, this boundary becomes invisible, probably due to the serpentinization of the forearc mantle wedge. The Lithosphere-Astheonsphere Boundary (LAB) of the subducted Nazca plate was clearly identified as a sharp boundary in the results obtained from the P and S receiver functions. The LAB lies at a depth of 80 km beneath the coastal area and dips from a depth of 100 km beneath the Coastal Cordillera to about 150 km underneath the Western Cordillera. High frequency PRF data enabled us to make confident estimates of the top and bottom of the Nazca lithosphere, which results in a lithospheric thickness of 57-60 km. In relation to the age of the Nazca plate, which is assumed to be ~ 50

  16. Study on unified fatigue strength assessment method for welded structure. Hot spot stress evaluating method for various combinations of plate thickness and weld leg length; Yosetsu kozo no toitsutekina hiro kyodo hyokaho ni kansuru kenkyu. Itaatsu to yosetsu ashinaga no kumiawase ni taisuru hot spot oryoku sanshutsu ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Nihei, K.; Inamura, F.; Koe, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1996-12-31

    There has been tried to apply unified assessment method using hot spot stress, which is effective to evaluate fatigue strength of fillet welded structures for ships and marine structures. This method can be applied to complicated structures and is independent of welding processes. In this study, first, stress analysis has been conducted for two-dimensional fillet welded joint models with various combinations of plate thickness and weld leg length of general fillet structures by means of boundary element method. Then, critical position, which is not affected by local stress concentration due to bead, was determined from the detailed stress distribution in the vicinity of weld toe. As a result, a general equation has been proposed to estimate the hot spot stress by one-point representative method. Second, the fatigue tests of typical fillet welded joints have been conducted by applying this method. Consequently, it was demonstrated that the unified fatigue strength can be evaluated by the S-N data based on hot spot stress range determined from the proposed equation, independent of structural stress concentration. 22 refs., 14 figs.

  17. Closed-form solution for free vibration of piezoelectric coupled annular plates using Levinson plate theory

    Science.gov (United States)

    Hosseini Hashemi, Sh.; Es'haghi, M.; Karimi, M.

    2010-04-01

    Free vibration analysis of annular moderately thick plates integrated with piezoelectric layers is investigated in this study for different combinations of soft simply supported, hard simply supported and clamped boundary conditions at the inner and outer edges of the annular plate on the basis of the Levinson plate theory (LPT). The distribution of electric potential along the thickness direction in the piezoelectric layer is assumed as a sinusoidal function so that the Maxwell static electricity equation is approximately satisfied. The differential equations of motion are solved analytically for various boundary conditions of the plate. In this study the closed-form solution for characteristic equations, displacement components of the plate and electric potential are derived for the first time in the literature. To demonstrate the accuracy of the present solution, comparison studies is first carried out with the available data in the literature and then natural frequencies of the piezoelectric coupled annular plate are presented for different thickness-radius ratios, inner-outer radius ratios, thickness of piezoelectric, material of piezoelectric and boundary conditions. Present analytical model provides design reference for piezoelectric material application, such as sensors, actuators and ultrasonic motors.

  18. Effect of Slurry Composition on Plate Weight in Ceramic Shell Investment Casting

    Science.gov (United States)

    Sidhu, Balwinder Singh; Kumar, Pradeep; Mishra, B. K.

    2008-08-01

    This paper deals with the study of the effect of primary slurry parameters on the plate weight (ceramic retention test) in ceramic shell investment casting process. Four controllable factors of the zircon flour and fused-silica powder based slurries were studied at three levels each by Taguchi’s parametric approach and single-response optimization of plate weight was conducted to identify the main factors controlling its stability. Variations in coating thickness with plate weight were calculated for each slurry and ceramic shell moulds were made on wax plate using primary slurry and coarse fused-silica sand as stucco. The Scanning Electronic Microscopy (SEM) technique has been used to study the surface morphology of zircon flour and fused silca powder particles as well as primary coating (shell surface). X-ray Diffraction (XRD) analysis was done to identify the various phases present in the ceramic slurry coating. Optical profilometer has been used to measure the surface roughness of the shells. The result reveals that the surface condition of shell can be improved by increasing the plate weight, corresponding to higher filler loading in the slurry. Confirmation experiments were conducted at an optimal condition showed that the surface quality of the ceramic shell mould were improved significantly. Castings were produced using Al-7%Si alloy in recommended parameters through ceramic shell investment casting process. Surface roughness of the produced casting were measured and presented in this paper.

  19. Highly curved microchannel plates

    Science.gov (United States)

    Siegmund, O. H. W.; Cully, S.; Warren, J.; Gaines, G. A.; Priedhorsky, W.; Bloch, J.

    1990-01-01

    Several spherically curved microchannel plate (MCP) stack configurations were studied as part of an ongoing astrophysical detector development program, and as part of the development of the ALEXIS satellite payload. MCP pairs with surface radii of curvature as small as 7 cm, and diameters up to 46 mm have been evaluated. The experiments show that the gain (greater than 1.5 x 10 exp 7) and background characteristics (about 0.5 events/sq cm per sec) of highly curved MCP stacks are in general equivalent to the performance achieved with flat MCP stacks of similar configuration. However, gain variations across the curved MCP's due to variations in the channel length to diameter ratio are observed. The overall pulse height distribution of a highly curved surface MCP stack (greater than 50 percent FWHM) is thus broader than its flat counterpart (less than 30 percent). Preconditioning of curved MCP stacks gives comparable results to flat MCP stacks, but it also decreases the overall gain variations. Flat fields of curved MCP stacks have the same general characteristics as flat MCP stacks.

  20. Collaborative study comparing the spiral plate and aerobic plate count methods.

    Science.gov (United States)

    Gilchrist, J E; Donnelly, C B; Peeler, J T; Campbell, J E

    1977-07-01

    The spiral plate count method is a semiautomated plating technique that greatly reduces manpower and material costs normally associated with the pour plating technique. In this collaborative study, 8 laboratories compared the spiral and pour plating techniques, using 4 samples each of 3 products: frozen pumpkin pie, frozen chicken pot pie, and shampoo. The results show that 10 of the 12 comparisons of means of the pour and spiral methods were not significantly different; 2 values were significant at alpha = 0.01. Overall, the components of variance were less than that of the current milk standard, and the replicate per cent coefficient of variation was satisfactory. This study indicates that the spiral plate method is an acceptable alternative to the pour plate method; the spiral plate method has been adopted as official first action.

  1. Effect of Rolling Parameters on Plate Curvature during Snake Rolling

    Institute of Scientific and Technical Information of China (English)

    FU Yao; XIE Shuisheng; XIONG Baiqing; HUANG Guojie; CHENG Lei

    2012-01-01

    In order to predict the plate curvature during snake rolling,FE model was constructed based on plane strain assumption.The accuracy of the FE model was verified by the comparison between the plate curvature conducted by FE model and experiment respectively.By using FE model,the effect of offset distance,speed ratio,reduction,roll radius and initial plate thickness on the plate curvature during snake rolling was investigated.The experimental results show that,a proper offsetting distance can efficiently decrease plate curvature,however an excessive offsetting distance will increase plate curvature.A larger speed ratio,reduction will cause a large plate curvature,however a larger roll radius has effect to reduce plate curvature.Plate which undergoes a larger reduction and plate with a larger initial thickness always need a larger offset distance to keep the plate the minimum plate curvature,but for a larger roll radius a smaller offset distance is needed.

  2. Determination of apparent sampling thickness of sea surface microlayer

    Science.gov (United States)

    Li, Jun; Ding, Hai-Bing; Wu, Zhi-Jian; Zhang, Zheng-Bin; Liu, Lian-Sheng

    1998-06-01

    In situ and laboratory studies of sea—surface microlayer sampling methods using glass plate, rotating drum, screen and funnel samplers were conducted. For glass plate and rotating drum samplers, surface microlayer samples of different thickness were collected by controlling their withdrawal rate and rotating rate. The relationships between pH, surface tension, the concentration of dissolved trace metals Cu and Pb, phosphate, particulate matters and sampling thickness were carefully investigated. It was shown that physicochemical and biological properties change obviously at the sampling thickness of about 50 μm, which is consistent with the mean thickness of the boundary film in the models of gas exchange across the sea surface. It is proposed that the apparent sampling thickness of the surface microlayer should be less than 40 μm. The factors affecting the sampling thickness are discussed, and the feasibility and applicable conditions for different sampling methods are evaluated.

  3. Nonlinear Vibration of Circular Plate with Variable Thickness

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    NonlinearVibrationofCircularPlatewithVariableThicknesYeZhiming(ShanghaiInstituteofAppliedMathematicsandMechanics)AbstractThis...

  4. Thick Plate Homogenization of Sandwich Panels Including Folded Cellular Cores

    OpenAIRE

    LEBEE, Arthur; Sab, Karam

    2011-01-01

    In the present work, we provide the Bending-Gradient homogenization scheme and apply it to a sandwich panel including the chevron pattern. It turns out that the shear forces stiffness of the sandwich panel is strongly influenced by a skin distortion phenomenon which cannot be neglected in conventional design.

  5. BOLIVAR & GEODINOS: Investigations of the Southern Caribbean Plate Boundary

    Science.gov (United States)

    Levander, A.; Schmitz, M.; Working Groups, B.

    2006-12-01

    , and is associated with broad uplift of the coastal regions. This is likely a site of continental growth. 2) The accretionary wedge terranes of the Southern Caribbean Deformed Belt formed in the Neogene, and extend as far east as the Aves Ridge. They result from SA overriding the CAR LIP, which for a number of reasons, we do not regard as normal subduction. 3) Igneous rocks on the islands of the Leeward Antilles arc, Aruba to Los Testigos, show a steady decrease in age from west to east (94.7-37.4 Ma), suggesting that the islands have been progressively captured from the Antilles arc by the plate boundary during the prolonged island arc-continent collision. Terrane capture models thus far cannot completely explain the data. 4) High (> 6.5 km/s) P-velocity bodies are found in the shallow crust along the main strike-slip faults along much of the plate boundary. We interpret these as elements of the HP/LT metamorphic terranes found in the adjacent thrust belts of central Venezuela. This suggests to us that displacement partitioning in the trench and subsequent strike-slip both play important roles in exhumation of the HP/LT terranes. 5) Crustal thickness variations in the plate boundary region are large (> 10 km), of short spatial wavelength (< 100 km), and indicate that the highest elevations of the coastal mountain belts are not supported isostatically.

  6. A high order theory for uniform and laminated plates

    Science.gov (United States)

    Lo, K. H.; Christensen, R. M.; Wu, E. M.

    1976-01-01

    A theory of plate deformation is derived which accounts for the effects of transverse shear deformation, transverse normal strain, and a nonlinear distribution of the in-plane displacements with respect to the thickness coordinate. The theory is compared with lower order plate theories through application to a particular problem involving a plate acted upon by a sinusoidal surface pressure. Comparison is also made with exact elasticity solution of this problem. It is found that when the ratio of the characteristic length of the load pattern to the plate thickness is of the order of unity, lower order theories are inadequate and the present high order theory is required to give meaningful results. Results are given for the bending of symmetric cross-ply and angle-ply laminates. Comparison with exact elasticity solutions indicates that the present plate theory is sufficiently accurate for predicting the behavior of thick laminates.

  7. Variational asymptotic modeling of composite dimensionally reducible structures

    Science.gov (United States)

    Yu, Wenbin

    A general framework to construct accurate reduced models for composite dimensionally reducible structures (beams, plates and shells) was formulated based on two theoretical foundations: decomposition of the rotation tensor and the variational asymptotic method. Two engineering software systems, Variational Asymptotic Beam Sectional Analysis (VABS, new version) and Variational Asymptotic Plate and Shell Analysis (VAPAS), were developed. Several restrictions found in previous work on beam modeling were removed in the present effort. A general formulation of Timoshenko-like cross-sectional analysis was developed, through which the shear center coordinates and a consistent Vlasov model can be obtained. Recovery relations are given to recover the asymptotic approximations for the three-dimensional field variables. A new version of VABS has been developed, which is a much improved program in comparison to the old one. Numerous examples are given for validation. A Reissner-like model being as asymptotically correct as possible was obtained for composite plates and shells. After formulating the three-dimensional elasticity problem in intrinsic form, the variational asymptotic method was used to systematically reduce the dimensionality of the problem by taking advantage of the smallness of the thickness. The through-the-thickness analysis is solved by a one-dimensional finite element method to provide the stiffnesses as input for the two-dimensional nonlinear plate or shell analysis as well as recovery relations to approximately express the three-dimensional results. The known fact that there exists more than one theory that is asymptotically correct to a given order is adopted to cast the refined energy into a Reissner-like form. A two-dimensional nonlinear shell theory consistent with the present modeling process was developed. The engineering computer code VAPAS was developed and inserted into DYMORE to provide an efficient and accurate analysis of composite plates and

  8. Inevitability of Plate Tectonics on Super-Earths

    CERN Document Server

    Valencia, Diana; Sasselov, Dimitar D

    2007-01-01

    The recent discovery of super-Earths (masses less or equal to 10 earth-masses) has initiated a discussion about conditions for habitable worlds. Among these is the mode of convection, which influences a planet's thermal evolution and surface conditions. On Earth, plate tectonics has been proposed as a necessary condition for life. Here we show, that super-Earths will also have plate tectonics. We demonstrate that as planetary mass increases, the shear stress available to overcome resistance to plate motion increases while the plate thickness decreases, thereby enhancing plate weakness. These effects contribute favorably to the subduction of the lithosphere, an essential component of plate tectonics. Moreover, uncertainties in achieving plate tectonics in the one earth-mass regime disappear as mass increases: super-Earths, even if dry, will exhibit plate tectonic behaviour.

  9. Virtual instrument for monitoring process of brush plating

    Institute of Scientific and Technical Information of China (English)

    JING Xue-dong; XU Bin-shi; WANG Cheng-tao; ZHU Sheng; DONG Shi-yun

    2004-01-01

    A virtual instrument(Ⅵ) was developed to monitor the technological parameters in the process of brush plating, including coating thickness, brush-plating current, current density, deposition rate, and brush plating voltage. Meanwhile two approaches were presented to improve the measurement accuracy of coating thickness. One of them aims at eliminating the random interferences by moving average filtering; while the other manages to calculate the quantity of electricity consumed accurately with rectangular integration. With these two approaches, the coating thickness can be measured in real time with higher accuracy than the voltage-frequency conversion method. During the process of plating all the technological parameters are displayed visually on the front panel of the Ⅵ. Once brush current or current density overruns the limited values, or when the coating thickness reaches the objective value, the virtual will alarm. With this Ⅵ, the solution consumption can be decreased and the operating efficiency is improved.

  10. Processless offset printing plates

    Directory of Open Access Journals (Sweden)

    Sanja Mahović Poljaček

    2015-06-01

    Full Text Available With the implementation of platesetters in the offset printing plate making process, imaging of the printing plate became more stable and ensured increase of the printing plate quality. But as the chemical processing of the printing plates still highly influences the plate making process and the graphic reproduction workflow, development of printing plates that do not require chemical processing for offset printing technique has been one of the top interests in graphic technology in the last few years. The main reason for that came from the user experience, where majority of the problems with plate making process could be connected with the chemical processing of the printing plate. Furthermore, increased environmental standards lead to reducing of the chemicals used in the industrial processes. Considering these facts, different types of offset printing plates have been introduced to the market today. This paper presents some of the processless printing plates.

  11. The thickness of glaciers

    Science.gov (United States)

    Faraoni, Valerio; Vokey, Marshall W.

    2015-09-01

    Basic formulae and results of glacier physics appearing in glaciology textbooks can be derived from first principles introduced in algebra-based first year physics courses. We discuss the maximum thickness of alpine glaciers and ice sheets and the relation between maximum thickness and length of an ice sheet. Knowledge of ordinary differential equations allows one to derive also the local ice thickness.

  12. Effect of openings collectors and solar irradiance on the thermal efficiency of flat plate-finned collector for indirect-type passive solar dryer

    Science.gov (United States)

    Batubara, Fatimah; Dina, Sari Farah; Klaudia Kathryn Y., M.; Turmuzi, M.; Siregar, Fitri; Panjaitan, Nora

    2017-06-01

    Research on the effect of openings solar collector and solar irradiance to thermal efficiency has been done. Solar collector by flat plate-finned type consists of 3 ply insulator namely wood, Styrofoam and Rockwool with thickness respectively are 10 mm, 25 mm and 50 mm. Absorber plate made of aluminum sheet with thickness of 0.30 mm, painted by black-doff. Installation of 19 units fins (length x height x thickness: 1000x20x10 mm) on the collector will increase surface area of absorber so it can receive much more solar energy. The solar collector cover is made of glass (thickness of 5 mm). During the research, the solar irradiance and temperature of collector are measured and recorded every five minutes. Temperature measurement performed on the surface of the absorber plate, inside of collector, surface cover and the outer side insulator (plywood). This data is used to calculate the heat loss due to conduction, convection and radiation on the collector. Openings of collectors vary as follows: 100%, 75%, 15% and 0% (total enclosed). The data collecting was conducted from 09.00 am to 17.00 pm and triplicates. The collector thermal efficiency calculated based on the ratio of the amount of heat received to the solar irradiance absorbed. The results show that each of openings solar collector has different solar irradiance (because it was done on a different day) which is in units of W/m2: 390 (100% open), 376 (75% open), 429 (15% open), and 359 (totally enclosed). The highest thermal efficiency is in openings variation of 15% opened. These results indicate that the efficiency of the collector is influenced by the solar irradiance received by the collector and the temperature on the collector plate. The highest thermal efficiency is in variation of openings 15%. These indicate that the efficiency of the collector was influenced by solar irradiance received by the collector and openings of the collector plate.

  13. Free vibration analysis of rectangular plates with central cutout

    Directory of Open Access Journals (Sweden)

    Kanak Kalita

    2016-12-01

    Full Text Available A nine-node isoparametric plate element in conjunction with first-order shear deformation theory is used for free vibration analysis of rectangular plates with central cutouts. Both thick and thin plate problems are solved for various aspect ratios and boundary conditions. In this article, primary focus is given to the effect of rotary inertia on natural frequencies of perforated rectangular plates. It is found that rotary inertia has significant effect on thick plates, while for thin plates the rotary inertia term can be ignored. It is seen that the numerical convergence is very rapid and based on comparison with experimental and analytical data from literature, it is proposed that the present formulation is capable of yielding highly accurate results. Finally, some new numerical solutions are provided here, which may serve as benchmark for future research on similar problems.

  14. An adaptive algorithm for pass adaptation in plate rolling

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new algorithm for pass adaptation in plate rolling is developed to improve thickness accuracy of plate products. The feature of the algorithm is that it uses the measured data rather than the schedule calculated data in adaptation, which leads to notable improvementin prediction accuracy of the rolling parameters and thickness accuracy of products can be improved accordingly. Results show that this adaptive algorithm is effective in practice.

  15. An adaptive algorithm for pass adaptation in plate rolling

    Institute of Scientific and Technical Information of China (English)

    ZhichunMu; WeimingLi; 等

    2002-01-01

    A new algorithm for pass adaptation in plate rolling is developed to improve thickness accuracy of plate products.The feature of the algorithm is that it uses the measured data rather than the schedule calculated data in adaptation,which leads to notable improvement in prediction accuracy of the rolling parmeters and thickness accuracy of products can be improved accordingly.Results show that this adaptive algorithm is effective in practice.

  16. Plate Tearing Under Mixed Mode Loading

    DEFF Research Database (Denmark)

    Andersen, Rasmus Grau; Nielsen, Kim Lau; Felter, Christian Lotz

    2016-01-01

    Cohesive-zone finite element modeling is often the technique of choice when dealing with extensive crack growth in large-scale ductile sheet metal structures. Shell elements with in-plane dimensions much larger than the plate thickness are typically employed to discretize the structure, and thus...

  17. Advances and Trends in Plate Buckling Research.

    Science.gov (United States)

    1982-12-01

    Hydrostatic State of In- Plane Stress. Instituto de Mecanica Aplicada No. 79-21 (Puerto Belgrano, Argentina), June 1979, 10 pp. (to be published). 38. Leissa...and Elastic Stability of Circular Plates With Thickness Varying in a Bilinear Fashion. Instituto de Mecanica Aplicada No. 81-23 (Puerto Belgrano

  18. The effects of lithospheric thickness and density structure on Earth's stress field

    Science.gov (United States)

    Naliboff, J. B.; Lithgow-Bertelloni, C.; Ruff, L. J.; de Koker, N.

    2012-01-01

    Lithospheric density and thickness variations are important contributors to the state of stress of the plates. The relationship between the lithosphere's isostatic state, subcrustal structure and stress field, however, remains unresolved due to the uncertainties on its thickness, composition and rheology. To study the influence of lithospheric structure on intraplate stresses, we use a new model of global lithospheric structure (TDL) that accounts for the presence of depleted mantle to explore the effects of isostatic compensation, mantle density structure, lithospheric thickness (base depth) and mechanical coupling within the lithosphere on wavelengths >200 km. We compute the mean lithostatic stress (Ω) of 2°× 2° lithospheric columns and then solve for the resulting global 'tectonic' stress field for a homogeneous elastic lithosphere with the finite element package ABAQUS. For a 100 km base depth, a historically common value for lithospheric thickness, tectonic stress patterns are largely insensitive to mantle density structure and match patterns in the world stress map, for both isostatically compensanted and non-compensated lithospheric structure. Increasing the base depth up to 250 km to account for thick continental roots, however, leads to sharp variations in the stress field between isostatic lithospheric structure models and TDL as the mantle portion of the lithosphere dominates Ω. Decreasing the model base depths up to 25 km as a proxy for vertical strength variations due to low viscosity channels within the crust or lithosphere as a whole, strongly alters stresses in magnitude, azimuth and regime, as the influence of topography and shallow crustal structure increases. We find that restricting spatial changes in Ω to a specified region to mimic lateral variations in strength also has a large effect on the resulting stresses, which leads us to conclude that regional models may not always be adequate for modelling the stress field. Strong deviations

  19. Two multilayered plate models with transverse shear warping functions issued from three dimensional elasticity equations

    CERN Document Server

    Loredo, Alexandre

    2013-01-01

    A multilayered plate theory which uses transverse shear warping functions issued from three-dimensional elasticity is presented. Two methods to obtain these transverse shear warping functions are detailed. The warping functions are issued from the variations of transverse shear stresses computed at special location points for a simply supported bending problem. The first method considers an exact 3D solution of the problem. The second method uses the solution provided by the model itself: the transverse shear stresses are computed by the integration of equilibrium equations. Hence, an iterative process is applied, the model being updated with the new warping functions, and so on. These two models are compared to other models and to analytical solutions for the bending of simply supported plates. Four different laminates and a sandwich are considered, length-to-thickness values varying from 2 to 100. An additional analytical solution that simulates the behavior of laminates under the plane stress hypothesis - ...

  20. Moment Capacity of Timber Reinforced with Punched Metal Plate Fasteners

    DEFF Research Database (Denmark)

    Nielsen, Jacob; Ellegaard, Peter

    of the section is obtained, resulting in a more economic truss design. In order to develop design methods for sections with plate reinforcement, bending tests have been made. The timber is Swedish spruce of strength class K-18(S8) and K-24(S10) with a thickness of 45 mm. The punched metal plate is from Gang...

  1. Oblique Impact of Projectile on Thin Aluminium Plates

    Directory of Open Access Journals (Sweden)

    W.U. Khan

    2003-04-01

    Full Text Available Experiments were performed, wherein cylindrical projectiles made of hardened steel were impacted on commercially available aluminium plates at different angles. Projectiles were of 12.8 mm diameter and plates were of 0.81 mm, 1.52mm and 1.91mm thicknesses. Based on the experimental results, an analytical model has been developed to predict the residual velocity of the projectile and the ballistic limit of the plate.

  2. Friction-stir welded defects and repairing weld process of thick aluminum plates with telescopic stir-pin%伸缩式搅拌头厚铝板搅拌摩擦焊缺陷及其补焊工艺

    Institute of Scientific and Technical Information of China (English)

    李博; 沈以赴; 胡伟叶

    2012-01-01

    By using the telescopic stir-pin, 25 mm-thickness 2219-T6 aluminum alloy couple plates were successfully friction-stir welded, and no plunge-through defect induced by the press amount of tool-shoulder was observed in the multi-pass repairing welding process. The microstructures in sound friction-stir welds, material-loss typed and weak-link typed weld defects were observed. The results show that the weld along the weld-thickness direction can be divided into shoulder-affected and pin-affected zones. The formation of defects is associated with the change of the welding parameters, and the inner material-loss typed defects follow volume conservation relationship. For the welds with different-size root flaws prepared by telescopic stir-pin, a non-linear relationship exists between the root-flaw depth and the weld tensile strength. In addition, under the unified welding parameters, by adjusting the telescopic pin length, the effects of multi-pass welding on the microstructure and properties of the resultant welds were investigated.%采用伸缩式搅拌头对25 mm板厚2219-T6铝合金进行搅拌摩擦焊,在多道补焊时避免搅拌头轴肩的二次下压量造成的底部焊穿.对25 mm板厚2219-T6搅拌摩擦焊焊缝的微观组织、材料缺失型缺陷及弱连接型缺陷进行观察.结果表明:焊缝沿厚度方向分为轴肩影响区和搅拌针影响区,焊接参数的变化与这两区域中缺陷的产生存在一定关系,焊缝中的材料缺失型缺陷遵循一定的体积守恒关系.利用伸缩式搅拌头制备不同尺寸的焊缝根部未焊透缺陷,发现未焊透的深度与焊缝抗拉强度呈非线性关系.在统一的焊接参数规范下,调整搅拌针伸出长度进行多道焊,研究多道补焊工艺对焊缝组织性能的影响.

  3. Indicial lift response function: an empirical relation for finite‐thickness airfoils, and effects on aeroelastic simulations

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Gaunaa, Mac; Heinz, Joachim Christian

    2013-01-01

    The aeroelastic response of wind turbines is often simulated in the time domain by using indicial response techniques. Unsteady aerodynamics in attached flow are usually based on Jones's approximation of the flat plate indicial response, although the response for finite‐thickness airfoils differs...... profile undergoing harmonic pitching motion in the attached flow region; the resulting lift forces are compared with computational fluid dynamics (CFD) simulations. The relevance for aeroelastic simulations of a wind turbine is also evaluated, and the effects are quantified in terms of variations...

  4. Semi-theoretical analyses of the concrete plate perforated by a rigid projectile

    Institute of Scientific and Technical Information of China (English)

    Hao Wu; Qin Fang; Ya-Dong Zhang; Zi-Ming Gong

    2012-01-01

    Based on the three-stage perforation model,a semi-theoretical analysis is conducted for the ballistic performances of a rigid kinetic projectile impacting on concrete plates.By introducing the projectile resistance coefficients,dimensionless formulae are proposed for depth of penetration (DOP),perforation limit thickness,ballistic limit velocity,residual velocity and perforation ratio,with the projectile nosed geometries and projectile-target interfacial friction taken into account.Based on the proposed formula for DOP and lots of penetration tests data of normal and high strength concrete targets,a new expression is obtained for target strength parameter.By comparisons between the results of the proposed formulae and existing empirical formulae and large amount of projectile penetration or perforation tests data for monolithic and segmented concrete targets,the validations of the proposed formulae are verified.It is found that the projectile-target interfacial friction can be neglected in the predictions of characteristic ballistic parameters.The dimensionless DOP for low-to-mid speed impacts of non-flat nosed projectiles increases almost linearly with the impact factor by a coefficient of 2/(πS).The anti-perforation ability of the multilayered concrete plates is dependent on both the target plate thickness and the projectile impact velocity.The variation range of the perforation ratio is 1-3.5 for concrete targets.

  5. Electromagnetic semitransparent $\\delta$-function plate: Casimir interaction energy between parallel infinitesimally thin plates

    CERN Document Server

    Parashar, Prachi; Shajesh, K V; Schaden, M

    2012-01-01

    We derive boundary conditions for electromagnetic fields on a $\\delta$-function plate. The optical properties of such a plate are shown to necessarily be anisotropic in that they only depend on the transverse properties of the plate. We unambiguously obtain the boundary conditions for a perfectly conducting $\\delta$-function plate in the limit of infinite dielectric response. We show that a material does not "optically vanish" in the thin-plate limit. The thin-plate limit of a plasma slab of thickness $d$ with plasma frequency $\\omega_p^2=\\zeta_p/d$ reduces to a $\\delta$-function plate for frequencies ($\\omega=i\\zeta$) satisfying $\\zeta d \\ll \\sqrt{\\zeta_p d} \\ll 1$. We show that the Casimir interaction energy between two parallel perfectly conducting $\\delta$-function plates is the same as that for parallel perfectly conducting slabs. Similarly, we show that the interaction energy between an atom and a perfect electrically conducting $\\delta$-function plate is the usual Casimir-Polder energy, which is verifi...

  6. Problem of Electromagnetoviscoelasticity for Multiply Connected Plates

    Science.gov (United States)

    Kaloerov, S. A.; Samodurov, A. A.

    2015-11-01

    A method for solving the problem of electromagnetoviscoelasticity for multiply connected plates is proposed. The small-parameter method is used to reduce this problem to a recursive sequence of problems of electromagnetoelasticity, which are solved by using complex potentials. A procedure is developed to determine, using complex potentials, approximations of the basic characteristics (stresses, electromagnetic-field strength, electromagnetic-flux density) of the electromagnetoelastic state at any time after application of a load. A plate with an elliptic hole is considered as an example. The variation in the electromagnetoelastic state of the multiply connected plate with time is studied

  7. Create Your Plate

    Medline Plus

    Full Text Available ... steps to get started: Using your dinner plate, put a line down the middle of the plate. ... vegetables . Now in one of the small sections, put grains and starchy foods. See this list of ...

  8. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets ... 2016 Articles from Diabetes Forecast® magazine: wcie-meal-planning, In this section Food Planning Meals Diabetes Meal ...

  9. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal ... Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook ...

  10. Food guide plate

    Science.gov (United States)

    ... chips or cookies. VEGETABLES: MAKE HALF OF YOUR PLATE FRUITS AND VEGETABLES Vegetables can be raw, fresh, ... as a snack. FRUITS: MAKE HALF OF YOUR PLATE FRUITS AND VEGETABLES Fruits can be fresh, canned, ...

  11. Growth Plate Fractures

    Science.gov (United States)

    ... the most widely used by doctors is the Salter-Harris system, described below. Type I Fractures These ... incidence of growth plate fractures peaks in adolescence. Salter-Harris classification of growth plate fractures. AAOS does ...

  12. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook ... Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart- ...

  13. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook ... Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart- ...

  14. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets you still choose the foods you want, but changes the portion sizes so you are getting larger ...

  15. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets ... Sleeve Custom jerseys for your Tour de Cure team benefits the cause. Ask the Experts: Learn to ...

  16. Preparation of 232Th Target by Molecule Plating

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>For the cross section measurement of the 232Th(α, 2n)234U reaction, thorium targets plated on the aluminium foil with 2 and 8 μm thickness are required. It was demanded that the mass thickness of the

  17. Global Plate Driving Forces at 50Ma

    Science.gov (United States)

    Butterworth, N. P.; Quevedo, L. E.; Müller, R. D.

    2011-12-01

    We apply a novel workflow utilising the BEM-Earth geodynamic software to analyse the global coupled plate-mantle dynamics at 50 Ma. A subduction history model based on kinematic data going as far back as 80 Ma was developed using the GPlates software. Advection of the plates into the mantle takes into account the absolute plate motions and lithospheric thickness derived from its age to produce an estimated density heterogeneity initial model condition in the upper mantle. The resulting global model consists of regions of a mantle viscosity and density structure that is post-processed to ensure smooth non-overlapping 3D surfaces. BEM-Earth is then free to evolve the model toward the 50 Ma solution. The evolution of the model is driven by self-consistent buoyancy driven mantle dynamics. We use the model velocity output to quantify changes in forces driving the plates before and after 50 Ma. We analyse the rapid change in plate motion of India, Africa and plates in the Pacific Ocean basin by considering slab-pull, ridge-push and mantle drag/suction forces that naturally result from such top-down driven mantle flow. We compare the results with plate kinematic reconstructions and other geological observations.

  18. Accelerated plate tectonics.

    Science.gov (United States)

    Anderson, D L

    1975-03-21

    The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence.

  19. Design Optimization and Structural Performance Evaluation of Plate Girder Bridge Constructed Using a Turn-Over Process

    Directory of Open Access Journals (Sweden)

    Gi-Ha Eom

    2017-03-01

    Full Text Available A recent trend in bridge construction has been the optimization of the cost-to-performance ratio. The most effective way to optimize the cost-to-performance ratio is to maximize the efficiency of the superstructure. Currently, many bridge engineers and designers favor two- or three- girder plate superstructures, due to their cost advantages. However, research on the performance enhancements of the I-type girder in two- or three- girder plate bridges is lacking. One of the most important performance improvement technologies for the I-type girder is the “preflex” method. In the preflex method, the specimen is inverted during the construction process to apply prestressed cambering to the specimen by using self-weight. However, a problem with the preflex construction method is difficulty with inverting the girder/plate system during the concrete curing process. Therefore, a new inverting system called Turn-Over (TO wheel was proposed. Using TO wheels, wider variations to the I-type girder design can be achieved. Using this TO construction method, various cross sectional designs of girder plate systems can be considered due to its easiness in inverting the girder/plate system. In this study, the location of concrete confinement sections between the steel I-beams and concrete plates was varied in an I-girder cross-sectional design. Design parameters included effective height, flange thickness, flange width, confining concrete section width, etc. From this study, the optimum cross-sectional design of the I-girder/concrete plate system was achieved. Then, a single 20 m TO girder/plate system and two 20 m TO girder bridges were constructed and tested to evaluate their performance. From the test, failure behavior, load carrying capacity, crack pattern, etc., are obtained. The results are discussed in detail in this paper.

  20. Create Your Plate

    Medline Plus

    Full Text Available ... Reset Plate Share Create Your Plate ! Share: Seven Simple Steps to Create Your Plate It's simple and effective for both managing diabetes and losing ... en.html Have Type 2 Diabetes? Our free program will help you live well. More from diabetes. ...

  1. A double layer plaque assay using spread plate technique for enumeration of bacteriophage MS2.

    Science.gov (United States)

    Cormier, Jiemin; Janes, Marlene

    2014-02-01

    Bacteriophage MS2 is used widely as a model organism to estimate pathogenic virus survival in various environments, and is usually quantified by plaque assay. Although current plaque assays work well in enumeration of MS2 in environmental samples, quantification of MS2 calls for better visibility and higher consistency. In an attempt to improve the visibility and consistency of the current plaque assay, spread plate technique was introduced, instead of the pour plate technique used commonly in existing methods. Other parameters that influence the outcome of the plaque assay were also compared. Using spread plate technique resulted in an increase of plaque size by approximately 50% and contributed to a better visibility. Addition of supplements (glucose, CaCl2 and thiamine); reduction of agar thickness and hardness, also contributed to enhanced plaque visibility and increased plaque count. Among all the conditions tested, a supplemented thin bottom agar (10ml 1% agar) and a supplemented thin top agar (10ml 0.45% agar) with spread plate technique gave the maximum countable plaques with a minimum standard deviation. When compared to other methods, it produced significantly higher plaque count and lower variation. The optimized plaque assay significantly improved visibility and consistency of the existing plaque assay methods and could be used in quantification of MS2.

  2. Evaluation of dose distributions in gamma chamber using glass plate detector

    Directory of Open Access Journals (Sweden)

    Narayan Pradeep

    2008-01-01

    Full Text Available A commercial glass plate of thickness 1.75 mm has been utilized for evaluation of dose distributions inside the irradiation volume of gamma chamber using optical densitometry technique. The glass plate showed linear response in the dose range 0.10 Kilo Gray (kGy to 10 kGy of cobalt-60 gamma radiation with optical sensitivity 0.04 Optical Density (OD /kGy. The change in the optical density at each identified spatial dose matrix on the glass plate in relation to the position in the irradiation volume has been presented as dose distributions inside the gamma chamber. The optical density changes have been graphically plotted in the form of surface diagram of color washes for different percentage dose rate levels as isodose distributions in gamma chamber. The variation in dose distribution inside the gamma chamber unit, GC 900, BRIT India make, using this technique has been observed within ± 15%. This technique can be used for routine quality assurances and dose distribution validation of any gamma chamber during commissioning and source replacement. The application of commercial glass plate for dose mapping in gamma chambers has been found very promising due to its wider dose linearity, quick measurement, and lesser expertise requirement in application of the technique.

  3. Non-destructive evaluation of laminated composite plates using dielectrometry sensors

    Science.gov (United States)

    Nassr, Amr A.; El-Dakhakhni, Wael W.

    2009-05-01

    The use of composite materials in marine, aerospace and automotive applications is increasing; however, several kinds of damages of composite materials may influence its durability and future applications. In this paper, a methodology was presented for damage detection of laminated composite plates using dielectrometry sensors. The presence of damage in the laminated composite plate leads to changes in its dielectric characteristics, causing variation in the measured capacitance by the sensors. An analytical model was used to analyse the influence of different sensor parameters on the output signals and to optimize sensor design. Two-dimensional finite element (FE) simulations were performed to assess the validity of the analytical results and to evaluate other sensor design-related parameters. To experimentally verify the model, the dielectric permittivity of the composite plate was measured. In addition, a glass fibre reinforced polymer (GFRP) laminated plate containing pre-fabricated slots through its thickness to simulate delamination and water intrusion defects was inspected in a laboratory setting. Excellent agreements were found between the experimental capacitance response signals and those predicated from the FE simulations. This cost-effective technique can be used for rapid damage screening, regular scheduled inspection, or as a permanent sensor network within the composite system.

  4. Minimum wall pressure coefficient of orifice plate energy dissipater

    Institute of Scientific and Technical Information of China (English)

    Wan-zheng Ai; Jia-hong Wang

    2015-01-01

    Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics:the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter;the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter;and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

  5. Minimum wall pressure coefficient of orifice plate energy dissipater

    Directory of Open Access Journals (Sweden)

    Wan-zheng AI

    2015-01-01

    Full Text Available Orifice plate energy dissipaters have been successfully used in large-scale hydropower projects due to their simple structure, convenient construction procedure, and high energy dissipation ratio. The minimum wall pressure coefficient of an orifice plate can indirectly reflect its cavitation characteristics: the lower the minimum wall pressure coefficient is, the better the ability of the orifice plate to resist cavitation damage is. Thus, it is important to study the minimum wall pressure coefficient of the orifice plate. In this study, this coefficient and related parameters, such as the contraction ratio, defined as the ratio of the orifice plate diameter to the flood-discharging tunnel diameter; the relative thickness, defined as the ratio of the orifice plate thickness to the tunnel diameter; and the Reynolds number of the flow through the orifice plate, were theoretically analyzed, and their relationships were obtained through physical model experiments. It can be concluded that the minimum wall pressure coefficient is mainly dominated by the contraction ratio and relative thickness. The lower the contraction ratio and relative thickness are, the larger the minimum wall pressure coefficient is. The effects of the Reynolds number on the minimum wall pressure coefficient can be neglected when it is larger than 105. An empirical expression was presented to calculate the minimum wall pressure coefficient in this study.

  6. Education and "Thick" Epistemology

    Science.gov (United States)

    Kotzee, Ben

    2011-01-01

    In this essay Ben Kotzee addresses the implications of Bernard Williams's distinction between "thick" and "thin" concepts in ethics for epistemology and for education. Kotzee holds that, as in the case of ethics, one may distinguish between "thick" and "thin" concepts of epistemology and, further, that this distinction points to the importance of…

  7. Thick film hydrogen sensor

    Science.gov (United States)

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  8. Hamiltonian system for orthotropic plate bending based on analogy theory

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on analogy between plane elasticity and plate bending as well as variational principles of mixed energy, Hamiltonian system is further led to orthotropic plate bending problems in this paper. Thus many effective methods of mathematical physics such as separation of variables and eigenfunction expansion can be employed in orthotropic plate bending problems as they are used in plane elasticity. Analytical solutions of rectangular plate are presented directly, which expands the range of analytical solutions. There is an essential distinction between this method and traditional semi-inverse method. Numerical results of orthotropic plate with two lateral sides fixed are included to demonstrate the effectiveness and accuracy of this method.

  9. Upper mantle structure of the Pacific and Philippine Sea plates revealed by seafloor seismic array observations

    Science.gov (United States)

    Isse, Takehi; Shiobara, Hajime; Suetsugu, Daisuke; Sugioka, Hiroko; Ito, Aki

    2016-04-01

    Seismic tomography studies have revealed the structure and dynamics of Earth's interior since the 1980s. However, the spatial resolution of the oceanic region is not good enough caused by sparse distribution of the seismic stations. The observations with broadband ocean-bottom seismographs (BBOBSs) since the 2000s enabled us to obtain seismic tomography models with higher spatial resolution. Our Japanese BBOBS group deployed more than 100 BBOBSs in the Pacific Ocean and obtained a high-resolution (300-500 km) three-dimensional shear wave velocity structure in the upper mantle beneath northwestern and south Pacific Ocean by using surface wave tomography technique. In the northwestern Pacific Ocean, where the Pacific plate subducts beneath the Philippine Sea plate, we found that the shear wave structure in the Philippine sea plate is well correlated with the seafloor age in the upper 120 km, three separate slow anomalies in the mantle wedge at depth shallower than 100 km beneath the Izu-Bonin-Mariana arc, which have a close relationship with the three groups of frontal and rear arc volcanoes having distinct Sr, Nd, and Pb isotope ratios, and that the Philippine Sea plate, which is a single plate, shows very large lateral variations in azimuthal and radial anisotropies compared with the Pacific plate. In the South Pacific Ocean, where midplate hotspots are concentrated, we found that the localized slow anomalies are found near hotspots in the upper mantle, estimated thickness of the lithosphere is about 90 km in average and is thinned by ~20 km in the vicinity of hotspots, which may represent thermal erosion due to mantle plumes.

  10. Selecting the form of plate corrugations of heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Pavlenko, V.F.; Nagornyi, V.E.; Dolinskii, V.M.; Kolokolova, T.G.; Chekhov, O.S.

    1987-03-01

    The authors, in the interest of enhancing the thermal efficiency of plate-type heat exchangers, seek to optimize the pattern and size of the corrugations and surface area of these plates as well as their thickness by assessing the corrosion and scale protection afforded by thermoplastic coatings applied to the carbon steels used in the plates. They test the coatings for the effects of pressure, temperature, and various corrosive media, and demonstrate a parametric technique for optimizing pressure and temperature distribution over the corrugated area, for reducing the potential for deformation, and for prolonging plate durability.

  11. A multilayer anisotropic plate model with warping functions for the study of vibrations reformulated from Woodcock's work

    CERN Document Server

    Loredo, Alexandre; 10.1016/j.jsv.2012.07.033

    2012-01-01

    In this paper, a plate model suitable for static and dynamic analysis of inhomogeneous anisotropic multilayered plates is described. This model takes transverse shear variation through the thickness of the plate into account by means of warping functions which are determined by enforcing kinematic and static assumptions at the layers interfaces. This model leads to a 10 x 10 behavior matrix in which membrane strains, bending curvatures, and transverse shear x and y-derivatives are coupled, and to a classical 2 x 2 shear behavior matrix. This model has been proven to be very efficient, especially when high ratios -up to 10E5- between the stiffnesses of layers are present. This work is related to Woodcock's model, so it can be seen as a reformulation of his work. However, it propose several enhancements: the displacement field is made explicit; it is reformulated with commonly used plate notations; laminate equations of motion are fully detailed; the place of this model relatively to other plate models is now e...

  12. Thermoelastic wave propagation in laminated composites plates

    Directory of Open Access Journals (Sweden)

    Verma K. L.

    2012-12-01

    Full Text Available The dispersion of thermoelastic waves propagation in an arbitrary direction in laminated composites plates is studied in the framework of generalized thermoelasticity in this article. Three dimensional field equations of thermoelasticity with relaxation times are considered. Characteristic equation is obtained on employing the continuity of displacements, temperature, stresses and thermal gradient at the layers’ interfaces. Some important particular cases such as of free waves on reducing plates to single layer and the surface waves when thickness tends to infinity are also discussed. Uncoupled and coupled thermoelasticity are the particular cases of the obtained results. Numerical results are also obtained and represented graphically.

  13. Electroless plating of thin gold films directly onto silicon nitride thin films and into micropores.

    Science.gov (United States)

    Whelan, Julie C; Karawdeniya, Buddini Iroshika; Bandara, Y M Nuwan D Y; Velleco, Brian D; Masterson, Caitlin M; Dwyer, Jason R

    2014-07-23

    A method to directly electrolessly plate silicon-rich silicon nitride with thin gold films was developed and characterized. Films with thicknesses plating free-standing ultrathin silicon nitride membranes, and we successfully plated the interior walls of micropore arrays in 200 nm thick silicon nitride membranes. The method is thus amenable to coating planar, curved, and line-of-sight-obscured silicon nitride surfaces.

  14. Significance of broad scale deformation of incoming plates at ocean trenches.

    Science.gov (United States)

    Ranero, C. R.; Calahorrano, A.; Grevemeyer, I.; Barckhausen, U.; Reichert, C. J.

    2012-12-01

    Recent seismic experiments in several ocean trenches indicate that oceanic lithosphere undergoes profound chemical changes due to percolation of water into the mantle along faults formed by bending-related deformation. When compared to earthquake activity the depth of mantle alteration seems to be related to the elastic thickness of the plate and thus controlled by bending stresses. This finding contrasts with previous speculation that large-great trench-outer-rise earthquakes were important in the formation of paths for water penetration into the plate. Large-great trench-outer-rise earthquakes are probably related to slab pull during decoupling along the interplate boundary and not necessarily controlled by bending stresses. Thus, current findings may seem to indicate that plate age and related elastic thickness at trenches may be be the key parameter that controls the amount of hydration that may occur in a plate. New multichannel seismic reflection images from northern Chile and a compilation of multibeam bathymetry display a remarkable variability of bending-related deformation along several hundreds kilometres of the subduction zone where plate age does not change significantly indicating that deformation and probably hydration might be very variable in space. A set of seismic profiles collected perpendicular to the trench and running several hundreds of kilometers into the incoming plate show that the bending-related deformation of the oceanic plate reaches the mantle well before the lithosphere plunges into the trench and develops a marked bend-faulting fabric observable in bathymetric maps. Similar conclusions can be reached from seismic images across the outer rise of the Cocos plate entering the Middle America Trench. Also, the combination of seismic images and swath bathymetry along the Chile trench shows a remarkable lateral variability in the intensity and style of deformation at the trench. The deformation appears to be controlled by the stresses

  15. Measurement of sediment and crustal thickness corrected RDA for 2D profiles at rifted continental margins: Applications to the Iberian, Gulf of Aden and S Angolan margins

    Science.gov (United States)

    Cowie, Leanne; Kusznir, Nick

    2014-05-01

    Subsidence analysis of sedimentary basins and rifted continental margins requires a correction for the anomalous uplift or subsidence arising from mantle dynamic topography. Whilst different global model predictions of mantle dynamic topography may give a broadly similar pattern at long wavelengths, they differ substantially in the predicted amplitude and at shorter wavelengths. As a consequence the accuracy of predicted mantle dynamic topography is not sufficiently good to provide corrections for subsidence analysis. Measurements of present day anomalous subsidence, which we attribute to mantle dynamic topography, have been made for three rifted continental margins; offshore Iberia, the Gulf of Aden and southern Angola. We determine residual depth anomaly (RDA), corrected for sediment loading and crustal thickness variation for 2D profiles running from unequivocal oceanic crust across the continental ocean boundary onto thinned continental crust. Residual depth anomalies (RDA), corrected for sediment loading using flexural backstripping and decompaction, have been calculated by comparing observed and age predicted oceanic bathymetries at these margins. Age predicted bathymetric anomalies have been calculated using the thermal plate model predictions from Crosby & McKenzie (2009). Non-zero sediment corrected RDAs may result from anomalous oceanic crustal thickness with respect to the global average or from anomalous uplift or subsidence. Gravity anomaly inversion incorporating a lithosphere thermal gravity anomaly correction and sediment thickness from 2D seismic reflection data has been used to determine Moho depth, calibrated using seismic refraction, and oceanic crustal basement thickness. Crustal basement thicknesses derived from gravity inversion together with Airy isostasy have been used to correct for variations of crustal thickness from a standard oceanic thickness of 7km. The 2D profiles of RDA corrected for both sediment loading and non-standard crustal

  16. Evaluating Picture Quality of Image Plates in Digital CR Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Byung Joon [Dept. of Radiological Tecnology, Choonhae College of Health Science, Ulsan (Korea, Republic of); Ji Tae Jeong [Dept. of Radiological Science, Kaya University, Kimhae (Korea, Republic of)

    2011-12-15

    Lab effectively supplemented the effects of outside radiation on image plates in the process of image acquisition of CR (computed radiography) systems and conducted for effective utilization in the case of clinical application. For this, Lab classified the storage places and time periods of image plates and compared and analyzed the differences between small dark spots. Lab also assessed the concentration distribution within the boundaries of images. Lab compared and measured the number of dark spots in a light room and a dark room depending on the storage places of image plates and found that dark spots slightly increased in an image plate when stored in a light room on the first and second days. Dark spots increased in proportion to the length of time stored. In the case of the image plate stored in a dark room, the number of dark spots remarkably decreased. With regard to picture quality as related to the location of image plates, the damage to picture quality could be reduced by locating regions of interest in the center. With regard to differences in sharpness following changes in the thickness of subjects, fewer scatter rays occurred and sharpness improved by reducing the thickness of subjects as much as possible. To get medical images of excellent quality, image plates should be managed effectively and it is desirable to keep images plates in dark iron plate boxes and not to expose them to outside radiation for a long time.

  17. Fuel Cell Thermal Management Through Conductive Cooling Plates

    Science.gov (United States)

    Colozza, Anthony J.; Burke, Kenneth A.

    2008-01-01

    An analysis was performed to evaluate the concept of utilizing conductive cooling plates to remove heat from a fuel cell stack, as opposed to a conventional internal cooling loop. The potential advantages of this type of cooling system are reduced stack complexity and weight and increased reliability through the reduction of the number of internal fluid seals. The conductive cooling plates would extract heat from the stack transferring it to an external coolant loop. The analysis was performed to determine the required thickness of these plates. The analysis was based on an energy balance between the thermal energy produced within the stack and the heat removal from the cooling plates. To accomplish the energy balance, the heat flow into and along the plates to the cooling fluid was modeled. Results were generated for various numbers of cells being cooled by a single cooling plate. The results provided cooling plate thickness, mass, and operating temperature of the plates. It was determined that utilizing high-conductivity pyrolitic graphite cooling plates can provide a specific cooling capacity (W/kg) equivalent to or potentially greater than a conventional internal cooling loop system.

  18. Charge Distribution Dependency on Gap Thickness of CMS Endcap RPC

    CERN Document Server

    Park, Sung K; Lee, Kyongsei

    2016-01-01

    We report a systematic study of charge distribution dependency of CMS Resistive Plate Chamber (RPC) on gap thickness. Prototypes of double-gap RPCs with six different gap thickness ranging from from 1.0 to 2.0 mm in 0.2-mm steps have been built with 2-mm-thick phenolic high-pressure-laminated plates. The efficiencies of the six gaps are measured as a function of the effective high voltages. We report that the strength of the electric fields of the gap is decreased as the gap thickness is increased. The distributions of charges in six gaps are measured. The space charge effect is seen in the charge distribution at the higher voltages. The logistic function is used to fit the charge distribution data. Smaller charges can be produced within smaller gas gap. But the digitization threshold should be also lowered to utilize these smaller charges.

  19. Ocean Sediment Thickness Contours

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ocean sediment thickness contours in 200 meter intervals for water depths ranging from 0 - 18,000 meters. These contours were derived from a global sediment...

  20. Origami of thick panels

    Science.gov (United States)

    Chen, Yan; Peng, Rui; You, Zhong

    2015-07-01

    Origami patterns, including the rigid origami patterns in which flat inflexible sheets are joined by creases, are primarily created for zero-thickness sheets. In order to apply them to fold structures such as roofs, solar panels, and space mirrors, for which thickness cannot be disregarded, various methods have been suggested. However, they generally involve adding materials to or offsetting panels away from the idealized sheet without altering the kinematic model used to simulate folding. We develop a comprehensive kinematic synthesis for rigid origami of thick panels that differs from the existing kinematic model but is capable of reproducing motions identical to that of zero-thickness origami. The approach, proven to be effective for typical origami, can be readily applied to fold real engineering structures.

  1. Injection molding of micro patterned PMMA plate

    Institute of Scientific and Technical Information of China (English)

    Yeong-Eun YOO; Tae-Hoon KIM; Tae-Jin JE; Doo-Sun CHOI; Chang-Wan KIM; Sun-Kyung KIM

    2011-01-01

    A plastic plate with surface micro features was injection molded to investigate the effect of pressure rise of melt on the replication of the micro structures. Prism pattern, which is used in many optical applications, was selected as a model pattern. The prism pattern is 50 μm in pitch and 108° in the vertical angle. The overall size of the plate was 335 mm×213 mm and the thickness of the plate varied linearly from 2.6 mm to 0.7 mm. The prism pattern was firstly machined on the nickel plated core block using micro diamond tool and this machined pattern core was installed in a mold for injection molding of prism patterned plate. Polymethyl methacrylate (PMMA) was used as a molding material. The pressure and temperature of the melt in the cavity were measured at different positions in the cavity and the replication of the pattern was also measured at the same positions. The results show that the pressure or temperature profile through the process depends on the shape and the size of the plate. The replication is affected by the temperature and pressure profiles at the early stage of filling, which is right after the melt reaches the position to be measured.

  2. Characterization of Tri-lab Tantalum Plate.

    Energy Technology Data Exchange (ETDEWEB)

    Buchheit, Thomas E.; Cerreta, Ellen K.; Deibler, Lisa Anne; Chen, Shu-Rong; Michael, Joseph R.

    2014-09-01

    This report provides a detailed characterization Tri-lab Tantalum (Ta) plate jointly purchased from HCStark Inc. by Sandia, Los Alamos and Lawrence Livermore National Laboratories. Data in this report was compiled from series of material and properties characterization experiments carried out at Sandia (SNL) and Los Alamos (LANL) Laboratories through a leveraged effort funded by the C2 campaign. Results include microstructure characterization detailing the crystallographic texture of the material and an increase in grain size near the end of the rolled plate. Mechanical properties evaluations include, compression cylinder, sub-scale tension specimen, micohardness and instrumented indentation testing. The plate was found to have vastly superior uniformity when compare with previously characterized wrought Ta material. Small but measurable variations in microstructure and properties were noted at the end, and at the top and bottom edges of the plate.

  3. Available: lead plate from COMPASS experiment

    CERN Multimedia

    The COMPASS collaboration

    2014-01-01

    The COMPASS collaboration would like to offer the possibility to take over a large and thick lead plate, since it is not required anymore in the spectrometer.   It has the following dimensions: thickness 100 mm, width 4.4 m and height 2.0 m, with a square hole in the middle with dimensions of 40 cm x 40 cm. The measured weight including the metal frame it is housed in is 10,180 kg. The CERN stores reference is 44.13.30.100.9. Please contact Erwin Bielert (erwin.bielert@cern.ch or 160539) for further information and details.

  4. Vibration analysis of orthotropic circular and elliptical nano-plates embedded in elastic medium based on nonlocal Mindlin plate theory and using Galerkin method

    Energy Technology Data Exchange (ETDEWEB)

    Anjomshoa, Amin; Tahani, Masoud [Ferdowsi University, Mashhad (Iran, Islamic Republic of)

    2016-06-15

    In the present study a continuum model based on the nonlocal elasticity theory is developed for free vibration analysis of embedded ortho tropic thick circular and elliptical nano-plates rested on an elastic foundation. The elastic foundation is considered to behave like a Pasternak type of foundations. Governing equations for vibrating nano-plate are derived according to the Mindlin plate theory in which the effects of shear deformations of nano-plate are also included. The Galerkin method is then employed to obtain the size dependent natural frequencies of nano-plate. The solution procedure considers the entire nano-plate as a single super-continuum element. Effect of nonlocal parameter, lengths of nano-plate, aspect ratio, mode number, material properties, thickness and foundation on circular frequencies are investigated. It is seen that the nonlocal frequencies of the nano-plate are smaller in comparison to those from the classical theory and this is more pronounced for small lengths and higher vibration modes. It is also found that as the aspect ratio increases or the nanoplate becomes more elliptical, the small scale effect on natural frequencies increases. Further, it is observed that the elastic foundation decreases the influence of nonlocal parameter on the results. Since the effect of shear deformations plays an important role in vibration analysis and design of nano-plates, by predicting smaller values for fundamental frequencies, the study of these nano-structures using thick plate theories such as Mindlin plate theory is essential.

  5. The New Plating Process on Plastics

    Institute of Scientific and Technical Information of China (English)

    MakotoImamura; JunOkada; KazuyaSatoh

    2004-01-01

    This process does not use general electroless plating solution containing formaldehyde(carcinogen) and phosphate(the object of waste water regulation). Furthermore. we succeeded in developing a new electroless copper plating solution which is usable semi-permanently by using the special reducing agent, The electroless deposition forms a very thin conductive film on substrate. Therefore, it can prevent some appearance defects (e.g. pits. pin-holes, laminations and inclusions) that occur in the conventional ones. In addition, it is possible to eliminate electroplating of copper from the process by applying the exclusive nickel solution in electroplating. Therefore, the obtained metal parts can be recycled as high quality stainless steel. Given this copper elecltoplating-free process, 25μ m-thick nickel deposition at the stage of electroplating, at least, enables the metal layers to show properties as versatile as those of the conventional(its total thickness is 25μm in the comparative conventional process).

  6. The New Plating Process on Plastics

    Institute of Scientific and Technical Information of China (English)

    Makoto Imamura; Jun Okada; Kazuya Satoh

    2004-01-01

    This process does not use general electroless plating solution containing formaldehyde(carcinogen) and phosphate(the object of waste water regulation). Furthermore, we succeeded in developing a new electroless copper plating solution which is usable semi-permanently by using the special reducing agent. The electroless deposition forms a very thin conductive film on substrate. Therefore, it can prevent some appearance defects (e.g. pits, pin-holes, laminations and inclusions) that occur in the conventional ones. In addition, it is possible to eliminate electroplating of copper from the process by applying the exclusive nickel solution in electroplating. Therefore, the obtained metal parts can be recycled as high quality stainless steel. Given this copper electroplating-free process, 25μ m-thick nickel deposition at the stage of electroplating, at least, enables the metal layers to show properties as versatile as those of the conventional(its total thickness is 25μ m in the comparative conventional process).

  7. Generalized Fibonacci zone plates

    CERN Document Server

    Ke, Jie; Zhu, Jianqiang

    2015-01-01

    We propose a family of zone plates which are produced by the generalized Fibonacci sequences and their axial focusing properties are analyzed in detail. Compared with traditional Fresnel zone plates, the generalized Fibonacci zone plates present two axial foci with equal intensity. Besides, we propose an approach to adjust the axial locations of the two foci by means of different optical path difference, and further give the deterministic ratio of the two focal distances which attributes to their own generalized Fibonacci sequences. The generalized Fibonacci zone plates may allow for new applications in micro and nanophotonics.

  8. Turbulent boundary layer over flexible plates

    Science.gov (United States)

    Rostami, Parand; Ioppolo, Tindaro

    2016-11-01

    This research describes the structure of a turbulent boundary layer flow with a zero pressure gradient over elastic plates. The elastic plates made of a thin aluminum sheets with thickness between 50 and 500 microns were placed on the floor of a subsonic wind tunnel and exposed to a turbulent boundary layer flow with a free stream velocity between 20m/s and 100m/s. The ceiling of the test section of the wind tunnel is adjustable so that a nearly zero pressure gradient is obtained in the test section. Hot-wire anemometry was used to measure the velocity components. Mean, fluctuating velocities and Reynolds stresses will be presented and compared with the values of a rigid plate.

  9. Analyzing the effects of size of hole on Plate failure

    Energy Technology Data Exchange (ETDEWEB)

    Behzad, Mohammadzadeh; Noh, Hyukchun [Sejong Univ., Seoul (Korea, Republic of)

    2013-05-15

    The load at critical point in which an infinitesimal increase in load can make the plate to buckle, is buckling load. When a plate element is subjected to direct compression, bending, shear, or a combination of these stresses in its plane, the plate may buckle locally before the member as a whole becomes unstable or before the yield stress of the material is reached. Holes can either increase or decrease critical load of a plate depending on its position and geometry. The presence of holes in plates will change the strength and stiffness, so the amounts of stress and its distribution which induce strain and buckling will be changed. This study deals with studying the buckling of plate with holes using finite element method(FEM). Buckling is one of the main reasons for steel members to fail during service life time. As plates are frequently used in the structures of nuclear power plants and in some cases making holes in plates is necessary, it is necessary to assay the capacity of the plates especially in terms of buckling. FEM is a useful approach which makes the plate analysis be performed with ease. This study relates the buckling load of plates with through-thickness holes to a dimensionless parameter (D/a). By increasing D/a ratio, the amount of plate strength is observed to be decreased. After D/a=0.5, the rate of decreasing is observed to be increased drastically. Therefore, it is better to use ratio D/a less than or equal to 0.5. As a further study, it is possible to investigate other aspects such as different thickness, different positions and so on.

  10. Spreading continents kick-started plate tectonics.

    Science.gov (United States)

    Rey, Patrice F; Coltice, Nicolas; Flament, Nicolas

    2014-09-18

    Stresses acting on cold, thick and negatively buoyant oceanic lithosphere are thought to be crucial to the initiation of subduction and the operation of plate tectonics, which characterizes the present-day geodynamics of the Earth. Because the Earth's interior was hotter in the Archaean eon, the oceanic crust may have been thicker, thereby making the oceanic lithosphere more buoyant than at present, and whether subduction and plate tectonics occurred during this time is ambiguous, both in the geological record and in geodynamic models. Here we show that because the oceanic crust was thick and buoyant, early continents may have produced intra-lithospheric gravitational stresses large enough to drive their gravitational spreading, to initiate subduction at their margins and to trigger episodes of subduction. Our model predicts the co-occurrence of deep to progressively shallower mafic volcanics and arc magmatism within continents in a self-consistent geodynamic framework, explaining the enigmatic multimodal volcanism and tectonic record of Archaean cratons. Moreover, our model predicts a petrological stratification and tectonic structure of the sub-continental lithospheric mantle, two predictions that are consistent with xenolith and seismic studies, respectively, and consistent with the existence of a mid-lithospheric seismic discontinuity. The slow gravitational collapse of early continents could have kick-started transient episodes of plate tectonics until, as the Earth's interior cooled and oceanic lithosphere became heavier, plate tectonics became self-sustaining.

  11. Testing Predictions of Continental Insulation using Oceanic Crustal Thicknesses

    Science.gov (United States)

    Hoggard, Mark; Shorttle, Oliver; White, Nicky

    2016-04-01

    The thermal blanketing effect of continental crust has been predicted to lead to elevated temperatures within the upper mantle beneath supercontinents. Initial break-up is associated with increased magmatism and the generation of flood basalts. Continued rifting and sea-floor spreading lead to a steady reduction of this thermal anomaly. Recently, evidence in support of this behaviour has come from the major element geochemistry of mid-ocean ridge basalts, which suggest excess rifting temperatures of ˜ 150 °C that decay over ˜ 100 Ma. We have collated a global inventory of ˜ 1000 seismic reflection profiles and ˜ 500 wide-angle refraction experiments from the oceanic realm. Data are predominantly located along passive margins, but there are also multiple surveys in the centres of the major oceanic basins. Oceanic crustal thickness has been mapped, taking care to avoid areas of secondary magmatic thickening near seamounts or later thinning such as across transform faults. These crustal thicknesses are a proxy for mantle potential temperature at the time of melt formation beneath a mid-ocean ridge system, allowing us to quantify the amplitude and duration of thermal anomalies generated beneath supercontinents. The Jurassic break-up of the Central Atlantic and the Cretaceous rifting that formed the South Atlantic Ocean are both associated with excess temperatures of ˜ 50 °C that have e-folding times of ˜ 50 Ma. In addition to this background trend, excess temperatures reach > 150 °C around the region of the Rio Grande Rise, associated with the present-day Tristan hotspot. The e-folding time of this more local event is ˜ 10 Ma, which mirrors results obtained for the North Atlantic Ocean south of Iceland. In contrast, crustal thicknesses from the Pacific Ocean reveal approximately constant potential temperature through time. This observation is in agreement with predictions, as the western Pacific was formed by rifting of an oceanic plate. In summary

  12. Crustal Thickness Across Alaska via Ps Receiver Functions and Gravity Data and Comparison to Lithospheric Structure

    Science.gov (United States)

    O'Driscoll, L.; Saltus, R. W.; Miller, M. S.; Porritt, R. W.

    2015-12-01

    The geologic mosaic of terranes, adjacent multi-phase plate boundary, rapid lateral topographic variations, and heterogeneous distribution of strain throughout Alaska all suggest strong heterogeneity of crustal architecture. We present a model of crustal thickness across the state is primarily constrained where seismic instrumentation has been deployed - dense coverage in the south-central region and sparse coverage in the north, west, and arc regions. P receiver functions (PRF) were calculated using an upgraded version of Funclab, a software module that retrieves data, calculates receiver functions, facilitates quality control, and calculates H-k stacking, depth mapping via binned Common Conversion Point stacking, and other backend products. 1,678 events and 262 stations yielded 102,000 preliminary PRF that were culled to 21,000 total RFs. Iterative time-domain deconvolution was performed about a 1 Hz central frequency for ZRT traces. Our model reproduces many of the Moho depth variations previously modeled by receiver functions and gravity. Thick (>60 km) crust below the Chugach and St. Elias Ranges transitions to ~40 km thick crust south of the Denali Fault. Immediately to the north, thin (29-35) crust is observed in central Alaska between the Alaska and Brooks Ranges. The central Brooks Range is observed to have a thick crustal root below its topographic high axis. Stations scattered throughout western Alaska and the Bering Sea regions generally show average (~35 km) thickness crust while displaying inter-station uniqueness in the form of stacked RFs. Below the forearc and central Alaska Range, the Yakutat slab Moho is also observed. To complete coverage for the state we use a gravity Moho model calibrated to our receiver function solutions. The resolution of gravity-derived Moho models is limited and can only produce a smoothed approximation of the actual Moho. Where receiver function results are dense we observe significant complexity to the Moho, consistent

  13. On the rotation and pitching of flat plates

    Science.gov (United States)

    Jin, Yaqing; Ji, Sheng; Chamorro, Leonardo P.

    2016-11-01

    Wind tunnel experiments were performed to characterize the flow-induced rotation and pitching of various flat plates as a function of the thickness ratio, the location of the axis of rotation and turbulence levels. High-resolution telemetry, laser tachometer, and hotwire were used to get time series of the plates motions and the signature of the wake flow at a specific location. Results show that a minor axis offset can induce high-order modes in the plate rotation under low turbulence due to torque unbalance. The spectral decomposition of the flow velocity in the plate wake reveals the existence of a dominating high-frequency mode that corresponds to a static-like vortex shedding occurring at the maximum plate pitch, where the characteristic length scale is the projected width at maximum pitch. The plate thickness ratio shows inverse relation with the angular velocity. A simple model is derived to explain the linear relation between pitching frequency and wind speed. The spectra of the plate rotation show nonlinear relation with the incoming turbulence, and the dominating role of the generated vortices in the plate motions.

  14. CHARACTERIZATION OF 6061 T651 ALUMINUM PLATES SUBJECTED TO HIGH-VELOCITY IMPACT LOADS

    Directory of Open Access Journals (Sweden)

    Evren ÖZŞAHİN

    2011-06-01

    Full Text Available Ballistic response of single or multi-layered metal armor systems subjected to kinetic energy pro-jectiles was investigated in many experimental, theoretical and numerical studies.In this study, 6061 T651 aluminum plates impacted by 9 mm bullets were investigated. Microstructural investigations have been carried out using optical microscopy. Microhardness values were used to determine the strength behavior of the plates. Influence of the plate thickness and impact velocity on the microstructure has been evaluated. It was concluded from the study that thinner plates are more prone to deformation hardening with high penetration depth values even at low impact velocities while thick plates are more susceptible to thermal softening with less penetration depths. Maximum hardness values were obtained just below the impact zone in both plate thicknesses.

  15. Blue Willow Story Plates

    Science.gov (United States)

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  16. Create Your Plate

    Medline Plus

    Full Text Available ... In Memory In Honor Become a Member En Español Type 1 Type 2 About Us Online Community ... Page Text Size: A A A Listen En Español Create Your Plate Create Your Plate is a ...

  17. Create Your Plate

    Medline Plus

    Full Text Available ... Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal Planning ... Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets ...

  18. Higher-Order Thickness Expansions for Cylindrical Shells

    Science.gov (United States)

    1991-09-01

    terms in the curvature-displacement rela- tions. This decision was based upon observations by Bushnell [12] that nonlinear terms in the curvature... Teoria Plyt Sredniej Grubbosci (Technical Theory of Plates with Moderate Thickness)," Rozprawy Inzynierskie (English Translation, Pol- ska Akademia Nauk

  19. Free Vibration Analysis of Patch Repaired Plates with a Through Crack by p-Convergent Layerwise Element

    Directory of Open Access Journals (Sweden)

    Jae S. Ahn

    2014-01-01

    Full Text Available The high-order layerwise element models have been used for damaged plates and shells in the presence of singularities such as crack, cutout, and delamination. In this study, the extension of a proposed finite element model has been tested for free vibration analysis of composite laminated systems. For the elements, three-dimensional displacement fields can be captured by layer-by-layer representation. For the elements, higher-order shape functions are derived by combination of one- and two-dimensional shape functions based on higher-order Lobatto shape functions, not using pure higher-order three-dimensional shape functions. The present model can relieve difficulty of aspect ratios in modeling very thin thickness of bonding layer. For verification of the model, natural frequencies and corresponding mode shapes are calculated and then compared with reference values for uncracked and cracked plates. Also, the vibration characteristics of one-sided patch repaired plates with a through internal crack are investigated with respect to variation of crack length, size and thickness of patch, and shear modulus of adhesive, respectively.

  20. Gauge-meter model building based on the effect of elastic deformation of rolls in a plate mill

    Institute of Scientific and Technical Information of China (English)

    Xianlei Hu; Zhaodong Wang; Zhong Zhao; Xianghua Liu; Guodong Wang

    2007-01-01

    The calculation error of the gauge-meter model will affect the gap setting precision and the self-learn precision of rolling force. The precision of the gauge-meter model is strongly influenced by plate width, working roll radius, backup roll radius, working roll crown, backup roll crown, and rolling force. The influence rules are hard to get by measuring. Taking a conventional 4-h plate mill as the research subject, these influences were transferred into the calculation of roll deflection and flattening deformation. To calculate these deformations, the theory of the influence function method was adopted. By modifying the traditional gauge-meter model, a novel model of the effect of roll elastic deformation on the gap setting was built by data fitting. By this model, it was convenient to analyze the variation caused by the rolling condition. Combining the elastic deformation model of rolls with the kiss-rolls method, a gauge-meter model was put forward for plate thickness prediction. The prediction precision of thickness was greatly improved by the new gaugemeter model.