Sample records for plating thickness standards

  1. Overriding plate thickness control on subducting plate curvature

    NASA Astrophysics Data System (ADS)

    Holt, Adam F.; Buffett, Bruce A.; Becker, Thorsten W.

    2015-05-01

    Subducting plate (SP) curvature exerts a key control on the amount of bending dissipation associated with subduction, and the magnitude of the subduction-resisting bending force. However, the factors controlling the development of SP curvature are not well understood. We use numerical models to quantify the role of SP rheology on the minimum radius of curvature, Rmin. We find that Rmin depends strongly on the SP thickness when the rheology is viscous. This dependence is substantially reduced when the SP behaves plastically, in line with the lack of correlation between Rmin and SP thickness on Earth. In contrast, plasticity leads to a strong positive correlation between Rmin and the overriding plate (OP) thickness. Using an analysis of Rmin versus OP thickness, we show that such a positive correlation exists on Earth. This suggests that OP structure, in conjunction with SP plasticity, is crucial in generating slab curvature systematics on Earth.

  2. Stress Analysis of Thick Laminated Composite and Sandwich Plates

    Microsoft Academic Search

    James M. Whitney

    1972-01-01

    Because of the relatively soft interlaminar shear modulus in high per formance composites, laminated plate theory based on the Kirchhoff hypothesis becomes inaccurate for determining gross plate response and internal stresses of thick composites and sandwich type laminates. In this paper a procedure is developed for accurately calculating the mechanical behavior of a thick laminated composite or sandwich plate of

  3. Static and dynamic stability of variable thickness annular plates

    NASA Astrophysics Data System (ADS)

    Mermertas, V.; Belek, H. T.

    1990-09-01

    The static and dynamic stability of variable thickness annular plates subject to periodic in-plane forces is studied. For this purpose a sector finite element model with the wave propagation technique of cyclic symmetry is developed. Plate thickness is both increased and decreased in the outward radial direction by the equations h = h max( {r}/{r o}) +? or h = h max( {r}/{r i}) -? respectively. The Mindlin plate finite element model is used to handle both the thick and thin plates. The instability regions are determined for a wide range of excitation frequencies with different boundary conditions by using Bolotin's method with the effect of static forces taken into account.

  4. Overriding plate thickness control on subducting slab curvature

    NASA Astrophysics Data System (ADS)

    Holt, Adam; Buffett, Bruce; Becker, Thorsten

    2015-04-01

    The curvature of a subducting plate exerts a key control on the amount of gravitational potential energy that is dissipated via bending during subduction. We use 2-D, numerical subduction models to explore the dependence of the subducting plate curvature, quantified as a radius of curvature, on the thickness of the overriding plate. This dependence is examined for subducting plates with viscous and visco-plastic rheologies. We find that the radius of curvature increases with overriding plate thickness for visco-plastic subducting plates, yet we do not observe this correlation for purely viscous subducting plates. The effective viscosity of the slab hinge is weakened in visco-plastic subducting plates and so external forces on the upper slab surface, which are dependent on overriding plate thickness, play a major role in dictating slab curvature. On Earth, we demonstrate that there is indeed a positive correlation between overriding plate thickness, estimated from seismic tomography, and radius of curvature, derived from earthquake hypocenter distributions. We therefore suggest that weakening of the subducting plate hinge, which occurs in the visco-plastic plates, is important in generating the slab curvature systematics observed on Earth.

  5. Overriding plate thickness control on subducting slab curvature

    NASA Astrophysics Data System (ADS)

    Holt, A.; Buffett, B. A.; Becker, T. W.

    2014-12-01

    The curvature of subducting lithosphere controls deformation due to bending at the trench, which results in a force that dissipates gravitational potential energy and may affect seismic coupling. We use 2-D, thermo-mechanical subduction models to explore the dependence of the radius of curvature on the thickness of the subducting and overriding plates for models with both viscous and effectively plastic lithospheric rheologies. Such a plastic rheology has been shown to reproduce the bending stresses/moment computed using a kinematic strain rate description and a laboratory derived composite rheology. Laboratory and numerical models show that the bending geometry of subducting slabs with a viscous rheology is strongly dependent on slab thickness; thicker plates have a larger radius of curvature. However, the curvature of subducting plates on Earth, illuminated by the distribution of earthquake hypocenters, shows little to no dependence on the plate thickness or age. Such an observation is instead compatible with plates that have a plastic rheology. Indeed, our numerical models show that the radius of curvature of viscous plates has a stronger dependence on subducting plate thickness than in equivalent plastic models. In viscous plates, the bending moment produces a torque, which balances the torque exerted by buoyancy. However, for the plastic plate case the bending moment saturates at a maximum value and so cannot balance the gravitational torque. The saturation of bending moment means that, (a) the radius of curvature of the bending region is not constrained by this torque balance, and, (b) other forces are required to balance the gravitational torque. We explore the role that the overriding plate could play in controlling the subducting plate curvature in plastic plate models where the bending stresses have saturated. For such plates, we find that increasing the thickness of the overriding plate causes the radius of curvature to increase. The same correlation is found in real subduction zones when the radius of curvature is compared with near-trench overriding lithospheric thickness. We suggest that the thickness of the overriding plate, through controlling the depth extent of the slab suction caused by the strong overriding plate, exerts a primary control on the curvature of subducting lithosphere.

  6. Behaviors of moiré fringes induced by plate thickness

    NASA Astrophysics Data System (ADS)

    Kim, Jaisoon; Son, Jung-Young; Lee, Kwang-Hoon; Lee, Hyoung; Park, Min-Chul

    2015-03-01

    The chirped moiré fringes in two superposed regularly patterned plates are investigated. When the top plate of the two superposed plates has a thickness, the periods of the moiré fringes become different from that of the plate with no thickness, and the fringes shift as the viewing position changes. These variations are induced because the pattern period of the bottom plate is virtually shortened by light refraction when it is viewed through the top plate due to the top plate’s refractive index. The amount of shortening is small but different for different thicknesses, viewing positions and distances and lengths of the plates. Since the shortening amount is a function of the viewing angle, its variation has a chirped signal pattern. It turns the pattern with a uniform line array into a chirp-signal-type line array pattern. As a consequence, the moiré fringes will be chirped, and they become more noticeable as the plate lengths increase. The simulation and experimental results are matched very closely.

  7. Transmission of Microwave Through Perforated Flat Plates of Finite Thickness

    Microsoft Academic Search

    Chao-Chun Chen

    1973-01-01

    Transmission characteristics of a thick conducting plate perforated with either circular or rectangular holes are presented. Simple explicit formulas for predicting energy leakage through a reflector surface are derived.

  8. Axisymmetric dynamic stability of polar orthotropic thick circular plates

    NASA Astrophysics Data System (ADS)

    Chen, L.-W.; Hwang, J.-R.

    1988-09-01

    Dynamic stability of polar orthotropic thick circular plates subjected to a periodic uniform radial stress is studied by the finite element method. An annular element based on the Mindlin plate theory is employed. The regions of dynamic instability for both clamped and simply supported edges are determined by Bolotin's method. The effects of various parameters on the dynamic stability are investigated.

  9. 46 CFR 32.59-1 - Minimum section modulus and plating thickness requirements-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... false Minimum section modulus and plating thickness requirements-TB/ALL. ...REQUIREMENTS Minimum Longitudinal Strength and Plating Thickness Requirements for Unclassed...59-1 Minimum section modulus and plating thickness requirements—TB/ALL....

  10. Oblique Perforation of Thick Metallic Plates by Rigid Projectiles

    NASA Astrophysics Data System (ADS)

    Chen, Xiaowei; Li, Qingming; Fan, Saucheong

    2006-08-01

    Oblique perforation of thick metallic plates by rigid projectiles 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.

  11. Methods for measuring plating thicknesses on TAB lead frames

    NASA Technical Reports Server (NTRS)

    Hagen, M. P.

    1977-01-01

    Plating three layer tape lead frames, used for tape automated bonding, offers a challenge to the electroplater because of nonuniform topography. Each lead frame contains large (typically .05 x. .05 inch) flat test pads located around the perimeter of the frame. These test pads are electrically connected to the bondable lead frame fingers which extend into an area in the center of the frame called the feature hole. The feature hole exposes these fingers to plating on all sides, while the test pads are exposed on only one side. In addition, the fingers are small in cross section (typically .003 x .0015 inches). Recent thickness measurements indicate that plating around the lead frame fingers is nearly twice as thick as that on test pad areas. Procedures and equipment were developed for measuring the thickness of the deposited material. Discussion was centered on the data obtained using the various measurement techniques and equipment.

  12. Asymmetric dynamic stability of thick annular plates based on a high-order plate theory

    NASA Astrophysics Data System (ADS)

    Chen, L.-W.; Hwang, J.-R.; Doong, J.-L.

    1989-05-01

    The asymmetric dynamic stability of thick annular plates subjected to a periodic uniform radial loading along the outer edge is studied by the finite element method. An annular element based on a high-order plate theory is used. The regions of dynamic instability are determined by Bolotin's method. The effects of various parameters on the dynamic stability are investigated.

  13. MODELING AND CONTROL OF PLATE THICKNESS IN HOT ROLLING MILLS

    Microsoft Academic Search

    Roland Heeg; Andreas Kugi; Olivier Fichet; Laurent Irastorza; Christophe Pelletier

    It is still common practice in industry to handle the thickness control problem of a rolling mill around a working point. The assumption of linearity is no longer valid if the mill is operated in a wider working range. In a reversing mill this is especially the case when the plate enters and leaves the mill stand from pass to

  14. Growth defects in thick ion-plated coatings

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1975-01-01

    Industrial ion plating conditions were selected to deposit metallic coatings such as copper, gold, and chromium 2 micrometer thick on metal and glass substrates. The surface finishes of 304 stainless steel, copper, and brass were utilized with mechanically and electrolytically polished surfaces. Nodular growth occurred in these coatings during ion plating as revealed by scanning electron microscopy. Surface irregularities such as scratches, steps, ledges, and so forth are responsible for outward growth, the typical cone type, whereas surface contaminants and loosely settled foreign particles are responsible for lateral growth; namely, the extreme localized surface outgrowths. These defect crystallographic features create porosity in the coatings when subjected to stresses and strains.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. A Framework for Adaptive Online Thickness Control at Plate Mill of Bhilai Steel Plant

    Microsoft Academic Search

    T. S. Prasanna Kumar; S. Rath; U. Bhaskar

    2010-01-01

    The Plate Mill at Bhilai Steel Plant (BSP) has two reversing stands, one functioning as the roughing mill, and the other as the finishing mill. The nominal thickness of the slab is 245 mm, which is reduced to about 40 mm as thick plates in the roughing mill and the thinner plates are processed further in the finishing mill. The Plate Mill

  17. A high-sensitivity, dual-plate, thickness-shear mode pressure sensor

    Microsoft Academic Search

    Yuantai Hu; Jiashi Yang; Yun Zeng; Qing Jiang

    2006-01-01

    We propose a dual-plate pressure sensor operating with pressure-induced frequency shifts of thickness-shear modes of a crystal plate resonator. Under an applied normal pressure, the dual-plate structure causes flexure in the crystal plate rattier than circumferential compression in usual thickness-shear pressure sensors. This suggests higher sensitivity because a plate responds to a normal pressure more than to a circumferential compression,

  18. Thickness measurement of transparent plates by wavelength stepping and a phase unwrapping algorithm

    NASA Astrophysics Data System (ADS)

    Yu, H.; Aleksoff, C.; Ni, J.

    2013-07-01

    Wavelength-scanning interferometry can measure thickness of transparent plates by differentiating optical path differences from multiple surface interference in the Fourier domain. However, nonlinear laser tuning deviates the measurement result from the nominal value. We propose a wavelength stepping measurement scheme combined with a phase unwrapping technique for two-dimensional transparent plate thickness measurements. Wavelength stepping allows practical high-resolution and large optics measurements. Systematic errors caused by nonlinearities in laser source stepping are reduced with synthetic wavelengths measured by a reference array using the phase unwrapping technique. Sub-micron measurement accuracy is achieved using the proposed method for a step height standard etched on a 3 mm quartz block.

  19. Model Adaptivity for Finite Element Analysis of Thin or Thick Plates Based on Equilibrated

    E-print Network

    Model Adaptivity for Finite Element Analysis of Thin or Thick Plates Based on Equilibrated Boundary paper 1 Introduction Analysis of plate structure with complex shape, loading and boundary con- ditions and accurate plate analysis, which is of great practical inter- est. Since plate structures are often combined

  20. The technology and welding joint properties of hybrid laser-tig welding on thick plate

    NASA Astrophysics Data System (ADS)

    Shenghai, Zhang; Yifu, Shen; Huijuan, Qiu

    2013-06-01

    The technologies of autogenous laser welding and hybrid laser-TIG welding are used on thick plate of high strength lower alloy structural steel 10CrNiMnMoV in this article. The unique advantages of hybrid laser-TIG welding is summarized by comparing and analyzing the process parameters and welding joints of autogenous laser welding laser welding and hybrid laser-TIG welding. With the optimal process parameters of hybrid welding, the good welding joint without visible flaws can be obtained and its mechanical properties are tested according to industry standards. The results show that the hybrid welding technology has certain advantages and possibility in welding thick plates. It can reduce the demands of laser power, and it is significant for lowering the aspect ratio of weld during hybrid welding, so the gas in the molten pool can rise and escape easily while welding thick plates. Therefore, the pores forming tendency decreases. At the same time, hybrid welding enhances welding speed, and optimizes the energy input. The transition and grain size of the microstructure of hybrid welding joint is better and its hardness is higher than base material. Furthermore, its tensile strength and impact toughness is as good as base material. Consequently, the hybrid welding joint can meet the industry needs completely.

  1. Estimates of elastic plate thicknesses beneath large volcanos on Venus

    NASA Technical Reports Server (NTRS)

    Mcgovern, Patrick J.; Solomon, Sean C.

    1992-01-01

    Megellan radar imaging and topography data are now available for a number of volcanos on Venus greater than 100 km in radius. These data can be examined to reveal evidence of the flexural response of the lithosphere to the volcanic load. On Earth, flexure beneath large hotspot volcanos results in an annual topographic moat that is partially to completely filled in by sedimentation and mass wasting from the volcano's flanks. On Venus, erosion and sediment deposition are considered to be negligible at the resolution of Magellan images. Thus, it may be possible to observe evidence of flexure by the ponding of recent volcanic flows in the moat. We also might expect to find topographic signals from unfilled moats surrounding large volcanos on Venus, although these signals may be partially obscured by regional topography. Also, in the absence of sedimentation, tectonic evidence of deformation around large volcanos should be evident except where buried by very young flows. We use analytic solutions in axisymmetric geometry for deflections and stresses resulting from loading of a plate overlying an inviscid fluid. Solutions for a set of disk loads are superimposed to obtain a solution for a conical volcano. The deflection of the lithosphere produces an annular depression or moat, the extent of which can be estimated by measuring the distance from the volcano's edge to the first zero crossing or to the peak of the flexural arch. Magellan altimetry data records (ARCDRs) from data cycle 1 are processed using the GMT mapping and graphics software to produce topographic contour maps of the volcanos. We then take topographic profiles that cut across the annular and ponded flows seen on the radar images. By comparing the locations of these flows to the predicted moat locations from a range of models, we estimate the elastic plate thickness that best fits the observations, together with the uncertainty in that estimate.

  2. Laser-Assisted Stir Welding of 25-mm-Thick HSLA65 Plate

    Microsoft Academic Search

    Keith M. Williamson

    2002-01-01

    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

  3. Thermal buckling of a simply supported moderately thick rectangular FGM plate

    Microsoft Academic Search

    Wu Lanhe

    2004-01-01

    Equilibrium and stability equations of a moderately thick rectangular plate made of functionally graded materials under thermal loads are derived based on the first order shear deformation theory. It is assumed that the material properties vary as a power form of thickness coordinate variable z. The derived equilibrium and buckling equations are then solved analytically for a plate with simply

  4. Free vibration and buckling analysis of clamped rectangular plates of variable thickness by the Galerkin method

    Microsoft Academic Search

    S. F. Ng; Y. Araar

    1989-01-01

    The problem of free vibration and buckling of isotropic clamped rectangular plates of variable thickness is investigated. The fourth order differential equation is solved by using Galerkin's variational method. The thickness of the plate varies linearly along the x axis and this variation is taken to be symmetric with respect to the middle surface. The parameters considered herein, for buckling

  5. 46 CFR 32.59-1 - Minimum section modulus and plating thickness requirements-TB/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...and plating thickness requirements-TB/ALL. 32.59-1 Section 32.59-1 ...Vessels That Carry Certain Oil Cargoes-TB/ALL § 32.59-1 Minimum section modulus and plating thickness requirements—TB/ALL. (a) As used in this section,...

  6. 46 CFR 32.59-1 - Minimum section modulus and plating thickness requirements-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...and plating thickness requirements-TB/ALL. 32.59-1 Section 32.59-1 ...Vessels That Carry Certain Oil Cargoes-TB/ALL § 32.59-1 Minimum section modulus and plating thickness requirements—TB/ALL. (a) As used in this section,...

  7. 46 CFR 32.59-1 - Minimum section modulus and plating thickness requirements-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...and plating thickness requirements-TB/ALL. 32.59-1 Section 32.59-1 ...Vessels That Carry Certain Oil Cargoes-TB/ALL § 32.59-1 Minimum section modulus and plating thickness requirements—TB/ALL. (a) As used in this section,...

  8. 46 CFR 32.59-1 - Minimum section modulus and plating thickness requirements-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...and plating thickness requirements-TB/ALL. 32.59-1 Section 32.59-1 ...Vessels That Carry Certain Oil Cargoes-TB/ALL § 32.59-1 Minimum section modulus and plating thickness requirements—TB/ALL. (a) As used in this section,...

  9. Three-Dimensional Vibration Analysis of Thick FGM Plate Strips Under Moving Line Loads

    Microsoft Academic Search

    Seyyed M. Hasheminejad; Ahmad Rafsanjani

    2009-01-01

    An exact three-dimensional analysis for steady-state dynamic response of an arbitrarily thick, isotropic, and functionally graded plate strip due to the action of a transverse distributed moving line load which is propagating parallel to the infinite simply supported edges of the plate at constant speed is presented based on the linear elasticity theory. The inhomogeneous plate is approximated by a

  10. Measurement of the residual stress distribution in a thick pre-stretched aluminum plate

    NASA Astrophysics Data System (ADS)

    Yuan, S. X.; Li, X. Q.; M, S.; Zhang, Y. C.; Gong, Y. D.

    2008-12-01

    Thick pre-stretched aluminum alloy plates are widely used in aircraft, while machining distortion caused by initial residual stress release in thick plates is a common and serious problem. To reduce the distortion, the residual stress distribution in thick plate must be measured. According to the characteristics of the thick pre-stretched aluminum alloy plate, based the elastic mechanical theory, this article deduces the modified layer-removal strain method adapting two different strain situations, which are caused by tensile and compressive stress. To validate this method, the residual stresses distribution along the thick direction of plate 2D70T351 is measured by this method, it is shown that the new method deduced in this paper is simple and accurate, and is very useful in engineering.

  11. PROCESS ANALYSIS AND SYNTHESIS OF LASER FORMING OF VARYING THICKNESS PLATE

    E-print Network

    Yao, Y. Lawrence

    such as compressor airfoils that are 3D geometries with large thickness variation, the analysis and process synthesis its thickness. In process analysis, the characteristics of bending deformation, and the evolution thickness plate are used to investigate the characteristics of in-plane strain and bending strain

  12. Error Analysis for the National Bureau of Standards 1016 mm Guarded Hot Plate

    Microsoft Academic Search

    B. Rennex

    1983-01-01

    An error analysis is given for the 1-meter Guarded Hot Plate at the National Bureau of Standards. This apparatus is used to measure the thermal resistance of insulation materials. The individual contributions to uncertainty in thermal resistance are discussed in detail. The total uncertainty is estimated to be less than 0.5 percent at sample thicknesses up to 150 mm (6

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

    NASA Technical Reports Server (NTRS)

    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.

  14. Measurement of relevant elastic and damping material properties in sandwich thick-plates

    E-print Network

    Paris-Sud XI, Université de

    Measurement of relevant elastic and damping material properties in sandwich thick-plates Marc R to measure relevant elastic and damping properties of the constituents of a sandwich structure, possibly) by comparing the results on different plates made of the same sandwich material. Key words: Elasticity

  15. Nonlinear transient analysis of moderately thick laminated composite sector plates

    NASA Astrophysics Data System (ADS)

    Sharma, Ashish; Nath, Y.; Sharda, H. B.

    2007-09-01

    This study presents a simple formulation for the nonlinear dynamic analysis of shear-deformable laminated sector plates made up of cylindrically orthotropic layers. The non-axisymmetric formulation in cylindrical coordinates is discretized in space domain using two-dimensional Chebyshev polynomials. Houbolt time marching is used for temporal discretization. Quadratic extrapolation is used for linearization along with fixed-point iteration for obtaining the results. Several combinations of simply supported, clamped and free edge conditions are considered. Convergence study has been carried out and the results are compared with the results of square plates. Effects of boundary conditions, moduli ratio, lamination scheme, sector angle and annularity on the transient deflection response are plotted graphically. Transient responses are compared for step, saw-tooth and sinusoidal loadings.

  16. Vibration and damping of laminated, composite-material plates including thickness-shear effects

    NASA Technical Reports Server (NTRS)

    Bert, C. W.; Siu, C. C.

    1972-01-01

    An analytical investigation of sinusoidally forced vibration of laminated, anisotropic plates including bending-stretching coupling, thickness-shear flexibility, all three types of inertia effects, and material damping is presented. In the analysis the effects of thickness-shear deformation are considered by the use of a shear correction factor K, analogous to that used by Mindlin for homogeneous plates. Two entirely different approaches for calculating the thickness-shear factor for a laminate are presented. Numerical examples indicate that the value of K depends on the layer properties and the stacking sequence of the laminate.

  17. Vibration of circular plates, of several thicknesses, with three supports 

    E-print Network

    Ballentine, John Richard

    1951-01-01

    employed, It, was sn improvement, over ths seismic piclnzp method. used. by the pz'svious fnvestiLratoz in that, it, reduced the ei'feet that, ths mass of the seismic pic'. mp had on the ectual displacement of the test specimen. It, also provided ssssnt..., The relative displacement, of the centez' of the plate contalninp the driving head bolt, could not be obt, ained because of She proJect, ion of the bolt, head above the surface of the . . late, The result. s obtclned from this metl"od. of pic!nzp proved...

  18. NONLINEAR MINDLIN PLATE EQUATIONS FOR THE THICKNESS-SHEAR VIBRATIONS OF CRYSTAL PLATES

    E-print Network

    Wang, Ji

    plate equations have wide applications in engineering fields with piezoelectric crystal resonators related to the driving electrical field. The need of nonlinear theory for the analysis of high frequency plate theory on other problems and subjects are more on pioneering attempt to expand displacement field

  19. Damage assessment and residual compression strength of thick composite plates with through-the-thickness reinforcements

    NASA Technical Reports Server (NTRS)

    Smith, Barry T.

    1990-01-01

    Damage in composite materials was studied with through-the-thickness reinforcements. As a first step it was necessary to develop new ultrasonic imaging technology to better assess internal damage of the composite. A useful ultrasonic imaging technique was successfully developed to assess the internal damage of composite panels. The ultrasonic technique accurately determines the size of the internal damage. It was found that the ultrasonic imaging technique was better able to assess the damage in a composite panel with through-the-thickness reinforcements than by destructively sectioning the specimen and visual inspection under a microscope. Five composite compression-after-impact panels were tested. The compression-after-impact strength of the panels with the through-the-thickness reinforcements was almost twice that of the comparable panel without through-the-thickness reinforcement.

  20. A study on friction stir welding of 12mm thick aluminum alloy plates

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  1. A new finite element formulation for vibration analysis of thick plates

    NASA Astrophysics Data System (ADS)

    Senjanovi?, Ivo; Vladimir, Nikola; Cho, Dae Seung

    2015-06-01

    A new procedure for determining properties of thick plate finite elements, based on the modified Mindlin theory for moderately thick plate, is presented. Bending deflection is used as a potential function for the definition of total (bending and shear) deflection and angles of cross-section rotations. As a result of the introduced interdependence among displacements, the shear locking problem, present and solved in known finite element formulations, is avoided. Natural vibration analysis of rectangular plate, utilizing the proposed four-node quadrilateral finite element, shows higher accuracy than the sophisticated finite elements incorporated in some commercial software. In addition, the relation between thick and thin finite element properties is established, and compared with those in relevant literature.

  2. Micro-Structural Study of Fretting Contact Caused by the Difference of the Tin Plating Thickness

    NASA Astrophysics Data System (ADS)

    Ito, Tetsuya; Sawada, Shigeru; Hattori, Yasuhiro; Saitoh, Yasushi; Tamai, Terutaka; Iida, Kazuo

    In recent years, there has been increasing demand to miniaturize wiring harness connectors in automobiles due to the increasing volume of electronic equipment and the reduction of the installation space allocated for the electronic equipment in automobiles for the comfort of the passengers. With this demand, contact failure caused by the fretting corrosion is expected to become a serious problem. In this report, we examined micro-structural observations of fretting contacts of two different tin plating thicknesses using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) and so on. Based on the results, we compared the microstructure difference of fretting contact caused by the difference of the tin plating thickness.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Effective elastic thickness of the Arabian plate: Weak shield versus strong platform

    NASA Astrophysics Data System (ADS)

    Chen, Bo; Kaban, Mikhail K.; El Khrepy, Sami; Al-Arifi, Nassir

    2015-05-01

    The fan wavelet method has been employed to calculate high-resolution maps of variations of the effective elastic thickness (EET) for the Arabian plate and surroundings. As the initial data, we use high-resolution gravity field, topography, and recent models of sedimentary basins. The western part of the plate is generally characterized by low to midvalues of EET (10-30 km) while the eastern one by high values (50 km and more in the core). This finding confirms that the pronounced asymmetry of the plate is rather associated with fundamental structural differences of the lithosphere than with a forced tilt of the plate due to the rifting in the west-southwest and subduction in the northeast. Therefore, the high topography in the western part of the plate is likely supported by relatively hot mantle that is also responsible for the decrease of EET. These results are generally in agreement with recent seismic tomography models.

  6. Analytical solution for free vibrations of moderately thick hybrid piezoelectric laminated plates

    NASA Astrophysics Data System (ADS)

    Askari Farsangi, M. A.; Saidi, A. R.; Batra, R. C.

    2013-10-01

    An analytical solution for free vibrations of a hybrid rectangular plate composed of a transversely isotropic, homogeneous and linear elastic core and face sheets made of a linear piezoelectric material is derived by assuming that the plate deformations are governed by the Mindlin plate theory. The electric potential in a piezoelectric layer satisfies Maxwell's equation and either open circuit or closed circuit boundary conditions on its major surfaces. For the hybrid plate coupled governing equations obtained from the Hamilton principle are decoupled by introducing four auxiliary scalar functions, and the Levy type analytical solution for free vibrations is derived. Plate frequencies as a function of the piezoelectric layer thickness and the plate aspect ratio are presented and discussed. It is found that the electric boundary conditions on major surfaces of the piezoelectric layers and the aspect ratio of the hybrid plate noticeably influence its frequencies. Significant contributions of the work include proposing the four scalar functions to uncouple the governing equations, providing an analytical solution for frequencies of the hybrid plate, and delineating effects of boundary conditions as well as of aspect ratio of the plate. Clamped: u0=v0=w=?x=?y=0 Free: N=N=Qy=M=M=0 Simply supported: N=N=w=M=M=0 The other two edges, x=0 and x=a, are assumed to be simply supported with boundary conditions analogous to Eq. (11c) applied on them. Free, clamped and simply supported edges are denoted by F, C and S, respectively.

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

    Microsoft Academic Search

    F. Ebrahimi; A. Rastgoo; M. H. Kargarnovin

    2008-01-01

    In this paper, a free vibration analysis of moderately thick circular functionally graded (FG) plate integrated with two thin\\u000a piezoelectric (PZT4) layers is presented based on Mindlin plate theory. The material properties of the FG core plate are assumed\\u000a to be graded in the thickness direction, while the distribution of electric potential field along the thickness of piezoelectric\\u000a layers is

  8. On the relations between cratonic lithosphere thickness, plate motions, and basal drag

    USGS Publications Warehouse

    Artemieva, I.M.; Mooney, W.D.

    2002-01-01

    An overview of seismic, thermal, and petrological evidence on the structure of Precambrian lithosphere suggests that its local maximum thickness is highly variable (140-350 km), with a bimodal distribution for Archean cratons (200-220 km and 300-350 km). We discuss the origin of such large differences in lithospheric thickness, and propose that the lithospheric base can have large depth variations over short distances. The topography of Bryce Canyon (western USA) is proposed as an inverted analog of the base of the lithosphere. The horizontal and vertical dimensions of Archean cratons are strongly correlated: larger cratons have thicker lithosphere. Analysis of the bimodal distribution of lithospheric thickness in Archean cratons shows that the "critical" surface area for cratons to have thick (>300 km) keels is >6-8 ?? 106 km2 . Extrapolation of the linear trend between Archean lithospheric thickness and cratonic area to zero area yields a thickness of 180 km. This implies that the reworking of Archean crust should be accompanied by thinning and reworking of the entire lithospheric column to a thickness of 180 km in accord with thickness estimates for Proterozoic lithosphere. Likewise, extrapolation of the same trend to the size equal to the total area of all Archean cratons implies that the lithospheric thickness of a hypothesized early Archean supercontinent could have been 350-450 km decreasing to 280-400 km for Gondwanaland. We evaluate the basal drag model as a possible mechanism that may thin the cratonic lithosphere. Inverse correlations are found between lithospheric thickness and (a) fractional subduction length and (b) the effective ridge length. In agreement with theoretical predictions, lithospheric thickness of Archean keels is proportional to the square root of the ratio of the craton length (along the direction of plate motion) to the plate velocity. Large cratons with thick keels and low plate velocities are less eroded by basal drag than small fast-moving cratons. Basal drag may have varied in magnitude over the past 4 Ga. Higher mantle temperatures in the Archean would have resulted in lower mantle viscosity. This in turn would have reduced basal drag and basal erosion, and promoted the preservation of thick (>300 km) Archean keels, even if plate velocities were high during the Archean. ?? 2002 Elsevier Science B.V. All rights reserved.

  9. Development of texture and texture gradient in Al-Cu-Li (2195) thick plate

    Microsoft Academic Search

    K. E. Crosby; R. A. Mirshams; S. S. Pang

    2000-01-01

    Texture resulting from micromechanical processing plays an important role in the anisotropy of materials. The determination of texture components is a useful way to present texture data. The types of components present in the texture of a material can be related to other material aspects including predictions of yield loci using polycrystal methods. Al-Cu-Li 2195 thick plate was cold rolled

  10. FREQUENCY-TEMPERATUREANALYSIS OF THICKNESS-SHEAR VIBRATIONS OF SC-CUTQUARTZ CRYSTAL PLATES WITH THE

    E-print Network

    Wang, Ji

    of SC-cut quartz crystal plates with the incremental thermal field theory proposed by Lee and Yong-87600467. With the incremental thermal field theory by Lee and Yong, we have truncated equations for the analysis of thickness with the thermal material constants [1].The incremental thermal field theory has been successfully adopted

  11. Signal characteristics of differential-pulsed eddy current sensors in the evaluation of plate thickness

    Microsoft Academic Search

    Young-Kil Shin; Dong-Myung Choi; Young-Joo Kim; Seung-Seok Lee

    2009-01-01

    Differential-pulsed eddy current (PEC) signals and their characteristics are investigated as tools for the evaluation of plate thickness by using the reflection-type PEC probe, which consists of an exciter coil and two sensor coils in a differential arrangement. Numerical and experimental signals are first compared to validate numerical simulation results, and good agreement between them is achieved. Investigation of differential

  12. Hadron energy resolution as a function of iron plate thickness and hadron direction resolution

    E-print Network

    Shyamasundar, R.K.

    Hadron energy resolution as a function of iron plate thickness and hadron direction resolution. In the interaction, (-) µ + N µ (+) - + X, where X represents hadrons. In order to reconstruct the energy of the hadrons emitted in the final state. The physics reach of ICAL can be improved by adding the information

  13. Air-coupled ultrasonic through-transmission thickness measurements of steel plates.

    PubMed

    Waag, Grunde; Hoff, Lars; Norli, Petter

    2015-02-01

    Non-destructive ultrasonic testing of steel structures provide valuable information in e.g. inspection of pipes, ships and offshore structures. In many practical applications, contact measurements are cumbersome or not possible, and air-coupled ultrasound can provide a solution. This paper presents air-coupled ultrasonic through-transmission measurements on a steel plate with thicknesses 10.15 mm; 10.0 mm; 9.8 mm. Ultrasound pulses were transmitted from a piezoelectric transducer at normal incidence, through the steel plate, and were received at the opposite side. The S1, A2 and A3 modes of the plate are excited, with resonance frequencies that depend on the material properties and the thickness of the plate. The results show that the resonances could be clearly identified after transmission through the steel plate, and that the frequencies of the resonances could be used to distinguish between the three plate thicknesses. The S1-mode resonance was observed to be shifted 10% down compared to a simple plane wave half-wave resonance model, while the A2 and S2 modes were found approximately at the corresponding plane-wave resonance frequencies. A model based on the angular spectrum method was used to predict the response of the through-transmission setup. This model included the finite aperture of the transmitter and receiver, and compressional and shear waves in the solid. The model predicts the frequencies of the observed modes of the plate to within 1%, including the down-shift of the S1-mode. PMID:25257299

  14. Active sound radiation control of a thick piezolaminated smart rectangular plate

    NASA Astrophysics Data System (ADS)

    Hasheminejad, Seyyed M.; Keshavarzpour, Hemad

    2013-09-01

    A spatial state-space formulation based on the linear three-dimensional piezoelasticity theory in conjunction with the classical Rayleigh integral acoustic radiation model is employed to obtain a semi-analytic solution for the coupled vibroacoustic response of a simply supported, arbitrarily thick, piezolaminated rectangular plate, set in an infinite rigid baffle. The smart structure is composed of an orthotropic supporting core layer integrated with matched volume velocity spatially distributed piezoelectric sensor and uniform force actuator layers. To assist controller design, a frequency-domain subspace-based identification technique is applied to estimate the coupled fluid-structure dynamics of the system. A standard linear quadratic Gaussian (LQG) optimal controller is subsequently synthesized and simulated based on the identified model and the optimal control input voltage for minimizing the estimated net volume velocity (total radiated power) of the panel is calculated in both frequency and time domains. Numerical simulations demonstrate the effectiveness of the adopted volumetric sensing/actuation technique in conjunction with the optimal control strategy for suppressing the predicted sound radiation response of a three-layered (NaNb5O15/Al/PZT4) sandwich panel in both frequency and time domains. The trade-off between dynamic performance and control effort penalty is examined for two different types of loading (i.e., impulsive and broadband random disturbances). Validity of the results is demonstrated by comparison with a commercial finite element package, as well as with the data available in the literature.

  15. The effects of plate thickness and perforation diameter on the supporting vapor velocity for a perforated plate fractionating column 

    E-print Network

    Cottle, John Ernest

    1948-01-01

    Ernest Cottle T. ' WFZCTS OZ ZI aT ' TJJIC!RJBSS A' D PDJPORnTIQJJ Dl. ~"~oirR OR TER SUPPORTING VAPOR V'"LOCITV FQR A P". ~JOB . '"M PLATLs PRACTIOIJaTI:0 COL!PC! A Thesis Submitted to the Paculty of t!ic ACricultural and '. :ochanical Colle, ;e... on Glycerin. 1 f, Supporting Velocity Ranges Moountered During a Plate Thickness Study on Glyoerin. . 47 18 . Supporting Velooity Ranges Rnoountered During a Liquid. Height Study on Glycerin, TARLRS Page I. A Study of the vffeots oi' perforation j...

  16. Evaluation of Palatal Plate Thickness of Maxillary Prosthesis on Phonation- A Comparative Clinical Study

    PubMed Central

    B, Sreedevi; Anne, Gopinadh; Manne, Prakash; Bindu O, Swetha Hima; Atla, Jyothi; Deepthi, Sneha; Chaitanya A, Krishna

    2014-01-01

    Background: Prosthodontic treatment involves clinical procedures which influence speech performance directly or indirectly. Prosthetic rehabilitation of missing teeth with partial or complete maxillary removable dentures influences the individual voice characteristics like Phonation, resonance etc. Aim: To evaluate the effect of Acrylic palatal plate thickness (1mm-3mm) of maxillary prosthesis on phonation. Materials and Methods: Twelve subjects were selected randomly between the age group of 20-25 years who have full complement of teeth and have no speech problems. Speech evaluation was done under four experimental conditions i.e. Without any experimental acrylic palatal plate (control), with experimental acrylic palatal plates of thickness 1 mm, 2 mm and 3 mm respectively. The speech material for phonation test consisted of Vowels sounds /a/, /i/, and /o/. Speech analysis to assess phonation was done using digital acoustic analysis (PRAAT software). The obtained results were statistically analyzed by One-way ANOVA and Tukey’s multiple post-hoc for comparison of four experimental conditions with respect to different vowel sounds. Results: Mean harmonics to noise ratio (HNR) values obtained for all the Experimental conditions did not show significant difference (p>0.05). In conclusion, an increase in the thickness of the acrylic palatal plate of maxillary prosthesis for about 1 mm - 3mm in complete or partial maxillary removable dentures resulted in no significant effect on phonation of vowel sounds /a/, /i/ and /o/. Conclusion: Increasing the thickness of the palatal plate from 1 mm to 3 mm has not shown any significant effect on the phonation. PMID:24959508

  17. An equilibrium method for prediction of transverse shear stresses in a thick laminated plate

    NASA Technical Reports Server (NTRS)

    Chaudhuri, R. Z.

    1986-01-01

    First two equations of equilibrium are utilized to compute the transverse shear stress variation through thickness of a thick laminated plate after in-plane stresses have been computed using an assumed quadratic displacement triangular element based on transverse inextensibility and layerwise constant shear angle theory (LCST). Centroid of the triangle is the point of exceptional accuracy for transverse shear stresses. Numerical results indicate close agreement with elasticity theory. An interesting comparison between the present theory and that based on assumed stress hybrid finite element approach suggests that the latter does not satisfy the condition of free normal traction at the edge. Comparison with numerical results obtained by using constant shear angle theory suggests that LCST is close to the elasticity solution while the CST is closer to classical (CLT) solution. It is also demonstrated that the reduced integration gives faster convergence when the present theory is applied to a thin plate.

  18. Influence of the laminate thickness in low velocity impact behavior of composite material plate

    Microsoft Academic Search

    Giovanni Belingardi; Roberto Vadori

    2003-01-01

    The low velocity impact behavior of carbon fiber-epoxy matrix laminates has been studied by experimental drop dart tests. The considered composite laminate is characterized by two different stacking sequences. Plates of three different values of the laminate thickness have been tested both by quasi-static and dynamic impact loading.The force–displacement curves, obtained during tests conducted with different impact velocities, are superimposed

  19. Mechanical response of thick laminated beams and plates subject to out-of-plane loading

    NASA Technical Reports Server (NTRS)

    Hiel, C. C.; Brinson, . F.

    1989-01-01

    The use of simplified elasticity solutions to determine the mechanical response of thick laminated beams and plates subject to out-of-plane loading is demonstrated. Excellent results were obtained which compare favorably with theoretical, numerical and experimental analyses from other sources. The most important characteristic of the solution methodology presented is that it combines great mathematical precision with simplicity. This symbiosis has been needed for design with advanced composite materials.

  20. Performance of a piezoelectric harvester in thickness-stretch mode of a plate.

    PubMed

    Yang, Jiashi; Zhou, Honggang; Hu, Yuantai; Jiang, Qing

    2005-10-01

    We studied mechanical-to-electrical power conversion of a piezoelectric plate driven mechanically into thickness-stretch vibrations. We have derived an analytical solution from the three-dimensional equations of linear piezoelectricity that shows the role of each of the physical parameters in determining the performance of such a piezoelectric device, usually measured by the output power density, the power efficiency, or both. Numerical results are included for illustrating the dependence of the device performance upon these physical parameters. PMID:16382641

  1. Performance of a piezoelectric harvester in thickness-stretch mode of a plate

    Microsoft Academic Search

    Jiashi Yang; Honggang Zhou; Yuantai Hu; Qing Jiang

    2005-01-01

    We studied mechanical-to-electrical power conversion of a piezoelectric plate driven mechanically into thickness-stretch vibrations. We have derived an analytical solution from the three-dimensional equations of linear piezoelectricity that shows the role of each of the physical parameters in determining the performance of such a piezoelectric device, usually measured by the output power density, the power efficiency, or both. Numerical results

  2. A Study on Segmented Multiple-Step Forming of Doubly Curved Thick Plate by Reconfigurable Multi-Punch Dies

    SciTech Connect

    Ko, Young Ho; Han, Myoung Soo; Han, Jong Man [Daewoo Shipbuilding and Marine Engineering Co., Ltd., 1, Aju-dong, Geoje, Gyeongnam, 656-714 (Korea, Republic of)

    2007-05-17

    Doubly curved thick plate forming in shipbuilding industries is currently performed by a thermal forming process, called as Line Heating by using gas flame torches. Due to the empirical manual work of it, the industries are eager for an alternative way to manufacture curved thick plates for ships. It was envisaged in this study to manufacture doubly curved thick plates by the multi-punch die forming. Experiments and finite element analyses were conducted to evaluate the feasibility of the reconfigurable discrete die forming to the thick plates. Single and segmented multiple step forming procedures were considered from both forming efficiency and accuracy. Configuration of the multi-punch dies suitable for the segmented multiple step forming was also explored. As a result, Segmented multiple step forming with matched dies had a limited formability when the objective shapes become complicate, while a unmatched die configuration provided better possibility to manufacture large curved plates for ships.

  3. Thickness effects on a cracked aluminum plate with composite patch repair

    NASA Astrophysics Data System (ADS)

    Schubbe, Joel Jon

    Post-repair fatigue crack growth was investigated in 3.175, 4.826, and 6.35 mm thick aluminum panels (508 mm long, 153 mm wide), asymmetrically repaired with boron/epoxy composite patches bonded to the plates with FM73 sheet adhesive. Patches were uniaxial with patch to panel stiffness ratios ranging from 0.46 to 1.3. Experimental fatigue tests were carried out at 120 MPa, R = 0.1, and 10 Hz (sinusoidal) to measure patched and unpatched face crack lengths, center crack opening displacements, and selected strains. Crack growth data was acquired using optical, eddy current, and post-test analysis methods. Crack growth rates were calculated using the incremental polynomial method. Test results showed increased plate thickness caused increased fatigue crack growth rates in both unrepaired and repaired panels. Thermally-induced bending due to patch bonding affects crack growth rates. Increased stiffness ratios increased life-spans and reduced crack growth anomalies such as retardation. Disbond growth is more dependent on crack size than on patch configuration and tends to accelerate when the crack grows beyond a critical length or where the patch changes thickness. A three-layer Mindlin plate finite element model was used as a two-dimensional analytical technique to predict patched and unpatched face reaction loads and displacements. This method uses a third plate layer to model the adhesive layer as a continuum. Constraint equations are used to enforce compatibility conditions along the plate-adhesive and adhesive patch interfaces. The calculated loads and displacements, in conjunction with the modified crack closure method, were used to compute stress intensity factors for the crack tips. Crack growth rates were calculated using experimentally determined material constants and the fatigue crack growth relationship (Paris Law) of the unpatched plate. Comparisons of the experimental to analytical curvatures of repaired panels showed excellent agreement for crack lengths up to 60-80 mm long. Enhancements to the predictions are presented to provide accurate life-span predictions. Crack growth rate and life-span predictions are consistent with their experimental counterparts at the unpatched face to within two life-spans. The present analysis is, thus, an effective tool to investigate the behavior of fatigue crack growth in thick and thin aluminum panels repaired with composite patches.

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

    NASA Technical Reports Server (NTRS)

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Integrated crustal thickness mapping and plate reconstructions for the high Arctic

    NASA Astrophysics Data System (ADS)

    Alvey, A.; Gaina, C.; Kusznir, N. J.; Torsvik, T. H.

    2008-10-01

    The plate tectonic history of the Amerasia Basin (High Arctic) and its distribution of oceanic and continental lithosphere are poorly known. A new method of gravity inversion with an embedded lithosphere thermal gravity anomaly correction has been applied to the NGA (U) Arctic Gravity Project (ArcGP) data to predict crustal thickness and continental lithosphere thinning factors which are used to test different plate reconstructions within the Arctic region. The inversion of gravity data to map crustal thickness variation within oceanic and rifted continental margin lithosphere requires the incorporation of a lithosphere thermal gravity anomaly correction for both oceanic and continental lithosphere. Oceanic lithosphere and stretched continental margin lithosphere produce a large negative residual thermal gravity anomaly (up to - 380 mGal), for which a correction must be made in order to determine realistic Moho depth by gravity anomaly inversion. The lithosphere thermal model used to predict the lithosphere thermal gravity anomaly correction may be conditioned using plate reconstruction models to provide the age and location of oceanic lithosphere. Three plate reconstruction models have been examined for the opening of the Amerasia Basin, two end member models and a hybrid model: in one end member model the Mendeleev Ridge is rifted from the Canadian margin while in the other it is rifted from the Lomonosov Ridge (Eurasia Basin), the hybrid model contains elements of both end member models. The two end member plate reconstruction models are consistent with the gravity inversion for their prediction of the location of oceanic lithosphere within the Canada Basin but fail in the Makarov and Western Podvodnikov Basins. The hybrid model is consistent with predictions of the location of the ocean-continent transition from continental lithosphere thinning factors obtained from gravity inversion. A crustal thickness of approximately 20 km is predicted for Late Cretaceous Makarov/Podvodnikov Basins which is similar to the value obtained from seismic refraction. We suggest that this method could be used for discriminating between various plate tectonic scenarios, especially in remote or poorly surveyed regions.

  7. A new sensor concept for simultaneous measurement of pressure, temperature and thickness of plate structures using modified wave propagation theory 

    E-print Network

    Lo, Tzu-Wei

    2005-11-01

    This thesis presents a multi-purpose sensor concept viable for the simultaneous measurement of pressure, temperature and thickness of plate structures. It also establishes the knowledge base necessary for future sensor ...

  8. A new sensor concept for simultaneous measurement of pressure, temperature and thickness of plate structures using modified wave propagation theory

    E-print Network

    Lo, Tzu-Wei

    2005-11-01

    This thesis presents a multi-purpose sensor concept viable for the simultaneous measurement of pressure, temperature and thickness of plate structures. It also establishes the knowledge base necessary for future sensor design. Thermal...

  9. Axisymmetric bending and buckling analysis of thick functionally graded circular plates using unconstrained third-order shear deformation plate theory

    Microsoft Academic Search

    A. R. Saidi; A. Rasouli; S. Sahraee

    2009-01-01

    In the present article, axisymmetric bending and buckling of perfect functionally graded solid circular plates are studied based on the unconstrained third-order shear deformation plate theory (UTST). The UTST releases the shear-free condition on the top and bottom surfaces of plate which can be particularly useful when the plate is subjected to contact friction or presented in a flow field

  10. An improved plate theory of order (1,2) for thick composite laminates

    NASA Technical Reports Server (NTRS)

    Tessler, A.

    1992-01-01

    A new (1,2)-order theory is proposed for the linear elasto-static analysis of laminated composite plates. The basic assumptions are those concerning the distribution through the laminate thickness of the displacements, transverse shear strains and the transverse normal stress, with these quantities regarded as some weighted averages of their exact elasticity theory representations. The displacement expansions are linear for the inplane components and quadratic for the transverse component, whereas the transverse shear strains and transverse normal stress are respectively quadratic and cubic through the thickness. The main distinguishing feature of the theory is that all strain and stress components are expressed in terms of the assumed displacements prior to the application of a variational principle. This is accomplished by an a priori least-square compatibility requirement for the transverse strains and by requiring exact stress boundary conditions at the top and bottom plate surfaces. Equations of equilibrium and associated Poisson boundary conditions are derived from the virtual work principle. It is shown that the theory is particularly suited for finite element discretization as it requires simple C(sup 0)- and C(sup -1)-continuous displacement interpolation fields. Analytic solutions for the problem of cylindrical bending are derived and compared with the exact elasticity solutions and those of our earlier (1,2)-order theory based on the assumed displacements and transverse strains.

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

    E-print Network

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

    2015-03-11

    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.

  12. Analysis of transient heat flow to thick-walled plates and cylinders. [to determine gas heat transfer coefficient

    NASA Technical Reports Server (NTRS)

    Powell, W. B.

    1973-01-01

    A methodology is described for the analysis of a transient temperature measurement made in a flat or curved plate subjected to convective heat transfer, such that the surface heat flux, the hot-gas temperture, and the gas heat transfer coefficient can be determined. It is shown that if the transient temperature measurement is made at a particular point located nearly midway in the thickness of the plate there is an important simplification in the data analysis process, in that the factor relating the surface heat flux to the measured rate of rise of temperature becomes invariant for a Fourier Number above 0.60 and for all values of the Biot Number. Parameters are derived, tabulated, and plotted which enable straightforward determination of the surface heat flux, the hot-gas temperature, of the plate, the rate of rise of temperature, the plate thickness and curvature, and the mean thermal properties of the plate material at the test temperature.

  13. Arctic Crustal Thickness and Oceanic Lithosphere Distribution from Gravity Inversion: Constraining Plate Reconstructions

    NASA Astrophysics Data System (ADS)

    Kusznir, N. J.; Alvey, A.; Roberts, A. M.

    2013-12-01

    Mapping crustal thickness, continental lithosphere thinning and oceanic lithosphere distribution represents a substantial challenge for the Polar Regions. Using gravity anomaly inversion, we have produced the first comprehensive maps of crustal thickness and oceanic lithosphere distribution for the Arctic. The Arctic region formed as a series of small distinct ocean basins leading to a complex distribution of oceanic crust, thinned continental crust, possible micro-continents and rifted continental margins. Mapping of continental lithosphere thinning factor and crustal thickness from gravity inversion provide predictions of ocean-continent transition structure and magmatic type and continent ocean boundary location independent of magnetic isochrons. Restoration of crustal thickness and continent-ocean boundary location from gravity inversion may be used to test plate tectonic reconstructions. Using crustal thickness and continental lithosphere thinning factor maps with superimposed shaded-relief free-air gravity anomaly, we improve the determination of pre-breakup rifted margin conjugacy and sea-floor spreading trajectory within the Arctic basins. By restoring crustal thickness & continental lithosphere thinning maps of the Eurasia Basin & NE Atlantic to their initial post-breakup configuration we show the geometry and segmentation of the rifted continental margins at their time of breakup, together with the location of highly-stretched failed breakup basins and rifted micro-continents. Our gravity inversion predicts thin crust and high continental lithosphere thinning factors in the Makarov, Podvodnikov, Nautilus and Canada Basins consistent with these basins being underlain by oceanic or highly thinned continental crust. Larger crustal thicknesses, in the range 20 - 30 km, are predicted for the Lomonosov, Alpha and Mendeleev Ridges. Moho depths predicted compare well with seismic estimates. Predicted very thin continental or oceanic crust under the North Chuchki Basin has major implications for understanding the plate tectonic history of the Amerasia Basin. Thinned continental crust rather than oceanic crust is predicted under the Laptev Sea. We interpret gravity inversion crustal thicknesses underneath Morris Jessop Rise & Yermak Plateau as continental crust which provided a barrier to the tectonic and palaeo-oceanic linkage between the Arctic & North Atlantic until the Oligocene. Before this time, we link the seafloor spreading within the Eurasia Basin to that in Baffin Bay. We determine Moho depth, crustal basement thickness, continental lithosphere thinning and ocean-continent transition location using a 3D spectral domain gravity inversion method which incorporates a lithosphere thermal gravity anomaly correction. The gravity anomaly contribution from sediments is included in the gravity inversion and assumes a compaction controlled sediment density increase with depth. A correction to the predicted continental lithospheric thinning derived from gravity inversion is made for volcanic material addition produced by decompression melting during continental rifting and seafloor spreading. Gravity anomaly and bathymetry data used in the gravity inversion are from the NGA (U) Arctic Gravity Project and IBCAO respectively; sediment thickness is from a new regional compilation.

  14. Measurement of fluid film thickness on the valve plate in oil hydraulic axial piston pumps (I)-bearing pad effects-

    Microsoft Academic Search

    Jong-Ki Kim; Jae-Youn Jung

    2003-01-01

    The tribological mechanism between the valve plate and the cylinder block in oil hydraulic axial piston pumps plays an important\\u000a role on high power density. In this study, the fluid film thickness between the valve plate and the cylinder block was measured\\u000a with discharge pressure and rotational speed by use of a gap sensor, and a slip ring system in

  15. Flaw growth behavior in thick welded plates of 2219-T87 aluminum at room and cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Forman, R. G.; Glorioso, S. V.; Medlock, J. D.

    1973-01-01

    Axial load fatigue and fracture tests were conducted on thick welded plates of 2219-T87 aluminum alloy to determine the tensile strength properties and the flaw growth behavior in electron beam, gas metal arc, and pulse current gas tungsten arc welds for plates 6.35 centimeters (2.5 in.) thick. The tests were conducted in room temperature air and in liquid nitrogen environments. Specimens were tested in both the as-welded and the aged after welding conditions. The experimental crack growth rate were correlated with theoretical crack growth rate predictions for semielliptical surface flaws.

  16. Crustal Thickness Variations Along the Southeastern Caribbean Plate Boundary From Teleseismic and Active Source Seismic Data

    NASA Astrophysics Data System (ADS)

    Bezada, M. J.; Niu, F.; Baldwin, T. K.; Pavlis, G.; Vernon, F.; Rendón, H.; Zelt, C. A.; Schmitz, M.; Levander, A.

    2006-12-01

    Insight into the topography of the Moho discontinuity beneath Venezuela has been progressively gained since the 1990's through seismic refraction studies carried out in the south and east of the country. More recently, both active and passive, land and marine seismic data were acquired by the U.S. BOLIVAR and Venezuelan GEODINOS projects to understand accretion processes and mechanisms for continental growth. The passive component includes an 18-month deployment of 27 PASSCAL broadband seismographs, a 12-month deployment of 15 OBSIP broadband instruments and an ongoing deployment of 8 Rice broadband seismometers. Additionally, data from the 34 BB stations of the national seismic network of Venezuela and the GSN SDV station, give a seismic dataset from 84 stations covering an area of ~750,000 km2. The active component includes 4 onshore-offshore refraction/wide angle reflection profiles as well as the recording of airgun blasts from offshore seismic lines by BB stations in mainland Venezuela and the Leeward Antilles. This abundance of datasets allows us to estimate Moho depths using different methods such as receiver functions, and forward and inverse modeling of wide-angle datasets, but also poses the challenge of reconciling the different values obtained to achieve robust results. Generally the active source and receiver function estimates are close to one another. We present a composite crustal thickness map showing a highly variable crustal thicknesses ranging from 15 km beneath the Caribbean LIP, to ~55 km beneath eastern Venezuela. Crustal thickness is strongly correlated with geologic terranes, but not always as expected. The thickest crust is found to exist in the east of the country, beneath the sedimentary basins north of the Orinoco River where depth to Moho exceeds 50 km. Crustal thickness beneath most of the Precambrian Guayana Shield is fairly constant at ~38 km . In contrast, we observe relatively thin (~25-30 km) crust in the eastern and western coastal mountains, suggesting a significant portion of the high topography of the costal mountain ranges has a dynamic origin. Crustal thickness changes of more than 10km are observed crossing the coast in the plate boundary zone, but are not always directly associated with the surface expression of the strike-slip fault system.

  17. Thickness resonances dispersion characteristics of a lossy piezoceramic plate with electrodes of arbitrary conductivity.

    PubMed

    Mezheritsky, Alex A; Mezheritsky, Alex V

    2007-12-01

    A theoretical description of the dissipative phenomena in the wave dispersion related to the "energytrap" effect in a thickness-vibrating, infinite thicknesspolarized piezoceramic plate with resistive electrodes is presented. The three-dimensional (3-D) equations of linear piezoelectricity were used to obtain symmetric and antisymmetric solutions of plane harmonic waves and investigate the eigen-modes of thickness longitudinal (TL) up to third harmonic and shear (TSh) up to ninth harmonic vibrations of odd- and even-orders. The effects of internal and electrode energy dissipation parameters on the wave propagation under regimes ranging from a short-circuit (sc) condition through RC-type relaxation dispersion to an opencircuit (oc) condition are examined in detail for PZT piezoceramics with three characteristic T -mode energy-trap figure-of-merit c-(D)(33)/c-(E)(44) values - less, near equal and higher 4 - when the second harmonic spurious TSh resonance lies below, inside, and above the fundamental TL resonanceantiresonance frequency interval. Calculated complex lateral wave number dispersion dependences on frequency and electrode resistance are found to follow the universal scaling formula similar to those for dielectrics characterization. Formally represented as a Cole-Cole diagram, the dispersion branches basically exhibit Debye-like and modified Davidson Cole dependences. Varying the dissipation parameters of internal loss and electrode conductivity, the interaction of different branches was demonstrated by analytical and numerical analysis. For the purposes of dispersion characterization of at least any thickness resonance, the following theorem was stated: the ratio of two characteristic determinants, specifically constructed from the oc and sc boundary conditions, in the limit of zero lateral wave number, is equal to the basic elementary-mode normalized admittance. As was found based on the theorem, the dispersion near the basic and nonbasic TL and TSh resonances reveal some simple representations related to the respective elementary admittance and showing the connection between the propagation and excitation problems in a continuous piezoactive medium. PMID:18276573

  18. A {1,2}-Order Plate Theory Accounting for Three-Dimensional Thermoelastic Deformations in Thick Composite and Sandwich Laminates

    NASA Technical Reports Server (NTRS)

    Tessler, A.; Annett, M. S.; Gendron, G.

    2001-01-01

    A {1,2}-order theory for laminated composite and sandwich plates is extended to include thermoelastic effects. The theory incorporates all three-dimensional strains and stresses. Mixed-field assumptions are introduced which include linear in-plane displacements, parabolic transverse displacement and shear strains, and a cubic distribution of the transverse normal stress. Least squares strain compatibility conditions and exact traction boundary conditions are enforced to yield higher polynomial degree distributions for the transverse shear strains and transverse normal stress through the plate thickness. The principle of virtual work is used to derive a 10th-order system of equilibrium equations and associated Poisson boundary conditions. The predictive capability of the theory is demonstrated using a closed-form analytic solution for a simply-supported rectangular plate subjected to a linearly varying temperature field across the thickness. Several thin and moderately thick laminated composite and sandwich plates are analyzed. Numerical comparisons are made with corresponding solutions of the first-order shear deformation theory and three-dimensional elasticity theory. These results, which closely approximate the three-dimensional elasticity solutions, demonstrate that through - the - thickness deformations even in relatively thin and, especially in thick. composite and sandwich laminates can be significant under severe thermal gradients. The {1,2}-order kinematic assumptions insure an overall accurate theory that is in general superior and, in some cases, equivalent to the first-order theory.

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

    NASA Astrophysics Data System (ADS)

    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 wear by increasing the energy into the material, another benefit of the proposed Laser Assisted Stir Welding (LASW is to reduce the width of the heat affected zone which typically has the lowest hardness in the weld region. Additionally, thermal modeling of the friction stir process shows that the heat input is asymmetric and suggests that the degree of asymmetry could improve the efficiency of the process. These asymmetries occur because the leading edge of the tool supplies heat to cold material while the trailing edge provides heat to material already preheated by the leading edge. As a result, flow stresses on the advancing side of the joint are lower than corresponding values on the retreating side. The proposed LASW process enhances these asymmetries by providing directional heating to increase the differential in flow stress across the joint and improve the stir tool efficiency. Theoretically the LASW process can provide the energy input to allow the flow stresses on the advancing side to approach zero and the stir efficiency to approach 100 percent. Reducing the flow stresses on the advancing side of the weld creates the greatest pressure differential across the stir weld and eliminates the possibility of voids on the advancing side of the joint. Small pressure differentials result in poor stir welds because voids on the advancing side are not filled by the plastic flow of material from the retreating side.

  20. Transient finite element analysis of deep penetration laser welding process in a singlepass butt-welded thick steel plate

    Microsoft Academic Search

    C. Carmignani; R. Mares; G. Toselli

    1999-01-01

    The laser welding residual stresses and strains in a rectangular thick steel plate are investigated by means of a fully three dimensional finite element analysis. Temperature field and stress–strain field decoupling is assumed to be essential in order to perform an efficient finite element analysis. Moreover, ad hoc constitutive elastoviscoplastic equations have been adapted in order to overcome the unreliable

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

    NASA Technical Reports Server (NTRS)

    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.

  2. Earthquakes, Plate Boundaries, and Depth Indiana Standard Indicators

    E-print Network

    Polly, David

    , volcanoes, trenches, and mountains. ES.1.24 ­ Understand and discuss continental drift, sea-floor spreading of the ocean and continental crust and the depth of earthquakes, and types of plate boundaries where or continental crust? · What is the explanation behind the earthquakes that do not occur at plate boundaries? #12

  3. COMPARISON OF TWO MODERATELY THICK PLATE ELEMENTS BASED ON THE ABSOLUTE NODAL COORDINATE FORMULATION

    Microsoft Academic Search

    Marko K. Matikainen; A. L. Schwab; Aki M. Mikkola

    2009-01-01

    Two formulations for a flexible 3-D quadrilateral moderatelythick plate element based on the absolute nodal coordinate formulation are comp ared. The two approaches consist of a fully parameterized plate element and a fully parameter ized plate element with linearized transverse shear angles to overcome slow convergence and cu rvature locking. For the sake of verification of the formulations and numerical

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Finite strip method for the free vibration and buckling analysis of plates with abrupt changes in thickness and complex support conditions

    Microsoft Academic Search

    Y. K. Cheung; F. T. K. Au; D. Y. Zheng

    2000-01-01

    The free vibration problem of a stepped plate supported on non-homogeneous Winkler elastic foundation with elastically mounted masses is formulated based on Hamilton's principle. The stepped plate is modelled by finite strip method. To overcome the problem of excessive continuity of common beam vibration functions at the location of abrupt change of plate thickness, a set of C1 continuous functions

  6. Observation of spatter formation mechanisms in high-power fiber laser welding of thick plate

    NASA Astrophysics Data System (ADS)

    Zhang, M. J.; Chen, G. Y.; Zhou, Y.; Li, S. C.; Deng, H.

    2013-09-01

    This paper aims to present the dynamic behaviors of spatter formation, and to clarify the spatter formation mechanisms in the high-power fiber laser welding of a thick plate at low welding speeds. We used a modified “sandwich” specimen to directly observe the geometry of the longitudinal keyhole wall. The dynamic behaviors of the keyhole, vapor plume, and melt pool with the formation of spatters were observed using high-speed imaging. The mechanisms of the formation of the spatter ejected from the top and bottom surfaces were analyzed. The recoil momentum associated with the energized vapor plume jet acts on the tips of the gauffers on the front keyhole wall and micro-droplets inside the keyhole, thereby resulting in the formation of high-speed micro-spatter. At partial penetration, the spatter ejected from the keyhole inlet is influenced mainly by the upward melt flow above the keyhole, melt displacement around the keyhole, and the strong shear stream of the directed vapor plume force. Moreover, some spatter droplets are accelerated through the vapor plume outside the keyhole. At full penetration of the melt, spatters are generated when the downward momentum of the melt due to downward flow and gravity, or vapor burst with an open keyhole, exceeds the surface tension forces. At full penetration of the keyhole, the crucial driving force for spatter generation is the viscous friction drag associated with high-speed motion of the energized vapor plume through the open keyhole. The welding process evolves into almost a cutting process at a lower welding speed.

  7. Three-dimensional thermal response of thick plate weldments: effect of layer-wise and piece-wise welding

    NASA Astrophysics Data System (ADS)

    Nami, M. R.; Kadivar, M. H.; Jafarpur, K.

    2004-07-01

    The thermal response of thick plate weldments under multi-layer and multi-block welding sequences is studied by the use of three-dimensional finite element models. The moving isotherm approach is applied to the modelling of inserted arc power and the temperature dependence of the material's thermal properties is considered as well. The addition of welded material that normally occurs during the welding is also simulated by the use of the element rebirth technique. Arc movement, welder speed, arc moving direction and the time lag between the sequences are also considered in this research. The results show that the number of layers in the welding of thick plates plays a significant role in the formation of the thermal profile, especially for those points that are located near the weld. For the far points this effect is very small and can be neglected. In the case of multi-block welding, the results showed that this kind of welding sequence not only changes the magnitudes of maximum temperatures but also significantly affects the distribution of isothermal surfaces in the whole domain. Moreover, the outcomes are practically feasible and the model can be recommended for analysis of thermal fields in thick plate weldments.

  8. Application of MMC model on simulation of shearing process of thick hot-rolled high strength steel plate

    NASA Astrophysics Data System (ADS)

    Dong, Liang; Li, Shuhui; Yang, Bing; Gao, Yongsheng

    2013-12-01

    Shear operation is widely used as the first step in sheet metal forming to cut the sheet or plate into the required size. The shear of thick hot-rolled High Strength Steel (HSS) requires large shearing force and the sheared edge quality is relatively poor because of the large thickness and high strength compared with the traditional low carbon steel. Bad sheared edge quality will easily lead to edge cracking during the post-forming process. This study investigates the shearing process of thick hot-rolled HSS plate metal, which is generally exploited as the beam of heavy trucks. The Modified Mohr-Coulomb fracture criterion (MMC) is employed in numerical simulation to calculate the initiation and propagation of cracks during the process evolution. Tensile specimens are designed to obtain various stress states in tension. Equivalent fracture strains are measured with Digital Image Correlation (DIC) equipment to constitute the fracture locus. Simulation of the tension test is carried out to check the fracture model. Then the MMC model is applied to the simulation of the shearing process, and the simulation results show that the MMC model predicts the ductile fracture successfully.

  9. Static, free vibration and buckling analysis of anisotropic thick laminated composite plates on distributed and point elastic supports using a 3-D layer-wise FEM

    Microsoft Academic Search

    A. R. Setoodeh; G. Karami

    2004-01-01

    A three-dimensional elasticity based layer-wise finite element method (FEM) is employed to study the static, free vibration and buckling responses of general laminated thick composite plates. Various mixed boundary conditions and free edge conditions are conveniently and accurately implemented. The methodology is employed in modeling the laminated composite plates resting on Winkler and Pasternak types of elastic foundations. Elastic line

  10. THE NONLINEAR THICKNESS-SHEAR VIBRATIONS OF AN INFINITE AND ISOTROPIC ELASTIC PLATE

    E-print Network

    Wang, Ji

    -shear vibration frequency, study mode coupling and mode conversion, and investigate thermal effect on the resonant functioning modes of quartz crystal resonators. For an analysis of vibrations, the Mindlin and Lee plate the available methods and improving our solution techniques for the coupled nonlinear vibrations of finite

  11. Layered Plating Specimens For Mechanical Tests

    NASA Technical Reports Server (NTRS)

    Thompson, Linda B.; Flowers, Cecil E.

    1991-01-01

    Layered specimens readily made in standard sizes for tensile and other tests of mechanical properties. Standard specimen of metal ordinarily difficult to plate to standard grip thickness or diameter made by augmentation with easier-to-plate material followed by machining to standard size and shape.

  12. Reinterpretation of the Effective Elastic Thickness in Terms of Young's Modulus Variation Applying the Analytical Solution for an Elastic Plate (ASEP) to the Barents Sea

    NASA Astrophysics Data System (ADS)

    Wienecke, S.; Braitenberg, C.; Ebbing, J.; Kukowski, N.

    2006-12-01

    We apply the analytical solution for an elastic plate (ASEP), which solves the 4th order differential equation for the flexure of a thin plate to the Barents Sea in order to calculate the flexural rigidity. To constrain our analysis we make use of a 3D density model based on the Barents50 model [Ritzmann et al. 2006]. The density model provides information about the crustal configuration, e.g. the Moho and the loading in the crust including all internal density variation. The loading in combination with the ASEP allows us to calculate the flexure Mohos, and by comparison with the reference Moho, the flexural rigidity distribution. The resulting flexural rigidity distributions will be used to validate tectonic concepts, e.g. the location of the proposed Caledonian suture. In the past the effective elastic thickness (EET) has been used synonymously for the flexural rigidity, since it was defined by the material parameters of Young's modulus and Poisson ratio, which were assumed to be constant. The application of the ASEP shows, that it is sufficient to operate with a constant value for the Poisson's ratio, as the variation does not lead to a significant change in the result. However, concerning the vertical and horizontal variation of crustal composition, which corresponds to a change of Young modulus by orders of magnitude - the use of a constant standard value in the calculation process is doubtful. For that reason the EET distribution was recalculated including the Young's modulus variation, which could be estimated by using the p- wave velocities of the Barents50 model. From the viewpoint of solid-state physics the elastic thickness concept should be reconceived. The EET corresponds theoretically to a thickness of a flexed plate, which consists of a material describable by a constant Young's modulus. Therefore the obtained EET distribution could be related to a Young's modulus variation, if the calculation was done with a constant assumed standard value. If the crust and the upper mantle have a non-uniform Young's modulus, the calculated flexural rigidity distribution is only valid for the crust but not for the lithosphere. These investigations ought to demonstrate the importance of the consideration of the Young's modulus variation in the EET calculation. Ritzmann, O., Maercklin, N., Faleide, J. I., Bungum, H., Mooney, W. D., and Detweiler, S. T., 2006, A 3D geophysical model of the crust in the greater Barents Sea region: Model construction and basement characterisation: Geophysical Journal International (submitted), p. 62.

  13. Open-ended rectangular waveguide for nondestructive thickness measurement and variation detection of lossy dielectric slabs backed by a conducting plate

    Microsoft Academic Search

    Sasan Bakhtiari; Stoyan I. Ganchev; Reza Zoughi

    1993-01-01

    Solutions for fields inside a slab of a generally lossy dielectric medium backed by a conducting plate, placed outside a waveguide-fed rectangular aperture, are used for the microwave nondestructive thickness measurement of such dielectric slabs. Upon construction of the waveguide terminating admittance expression from its variational form, an inverse problem is solved to extract the slab thickness form the conductance

  14. Simplified model for oblique penetration of long-rod into plates of finite thickness

    NASA Astrophysics Data System (ADS)

    Zhao, Guozhi

    A simplified calculation model describes the penetration phenomena of ricochet, embedment and perforation for long-rod penetrators impacting into homogeneous plates at various angles, and gives the profiles of craters and the bulge on the back of targets. The striking velocity range is from 900m/s to 1800m/s. The calculations for the model conform relatively well to test results.

  15. Estimation of ultrasonic guided wave mode conversion in a plate with thickness variation

    Microsoft Academic Search

    Younho Cho

    2000-01-01

    The hybrid boundary element method aimed at analyzing Lamb wave scattering from defects can provide us with an excellent numerical tool for tackling complicated mode conversion phenomena under waveguide thickness variation. In this paper, utilization of hybrid boundary element modeling for specific Lamb wave mode incidence situations with special energy distributions along the structural cross section is proposed for estimating

  16. Parameterization of hybrid laser-assisted oxygen cutting of thick steel plates

    NASA Astrophysics Data System (ADS)

    Ermolaev, G. V.; Kovalev, O. B.; Zaitsev, A. V.

    2013-04-01

    Specific features of hybrid laser-assisted oxygen cutting of mild steel sheets are studied theoretically and experimentally. The shape and geometrical size of a supersonic confuser-diffuser nozzle are demonstrated to play an important role in the formation of oxygen cutting jet. The numerical solution of three-dimensional Navier-Stokes equations reveals a pseudoshock phenomenon in the gas flow in a narrow channel, which is the reason for elevated roughness in the lower part of the cut under certain conditions. A method of the analytical calculation of effective cutting parameters, which depend on the material thickness, nozzle geometry, and range of oxygen pressure, is proposed. Engineering recommendations are formulated, which are used to perform full-scale experiments on an automated laser technological complex in cutting steel sheets upto 30-50 mm thick.

  17. Computational Study of a Plate Mounted Finite Cylinder: Aspect Ratio and Boundary Layer Thickness Effects

    NASA Astrophysics Data System (ADS)

    Hummer, Christopher J.

    The integration of protrusions on aircraft, whether they are antennas or sensor turrets, can impact both aircraft safety and performance. The protrusions vary in size and shape and where they are placed on the aircraft can greatly affect the flow around the structure. This work utilizes the power and adaptability of modern computational methods to analyze finite cylinders of various aspect ratios subjected to incoming flow of varying boundary layer thickness. The geometry and flow conditions for the analysis match a wind tunnel test completed by the University of Cincinnati in 2005. This flow is challenging to model computationally because the flow is largely separated and influenced by both ends of the cylinder. The four cylinders analyzed, labeled by their diameter and height in inches, are D2H5, D4H2, D4H5, and D4H10. These four cylinders were subjected to cross-flows with two different boundary layer thicknesses for a total of eight cases. The boundary layer thicknesses were 1.5" and 6.0". This work compared the computational results with both the wind tunnel results and with available literature. The results compared favorably with both and captured all primary flow features for this class of flows. Furthermore, the impacts of cylinder aspect ratio and boundary layer thickness were evident in the results. The lower the aspect ratio of the cylinder, the more the flow from the free-end dominates the wake. Higher aspect ratio cylinders can be divided into regions with juncture flow near the wall, Karman style shedding near the middle and free-end effects near the tip. This work also identifies a transitional cylinder aspect ratio where the flow transitions from segregated regions to being dominated by the free-end downwash. This work shows that modern computational methods are capable of modelling the complex flow about a finite cylinder and can provide valuable insight to aid in protrusion design and integration.

  18. 78 FR 65554 - Exhaust Emission Standards for New Aircraft Turbine Engines and Identification Plate for Aircraft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-01

    ...45 [Docket No.: FAA-2012-1333; Amendment No. 34-5A] RIN 2120-AK15 Exhaust Emission Standards for New Aircraft Turbine Engines and Identification Plate for Aircraft Engines Correction In rule document 2013-24712, appearing on pages...

  19. A Tool Measuring Remaining Thickness of Notched Acoustic Cavities in Primary Reaction Control Thruster NDI Standards

    NASA Technical Reports Server (NTRS)

    Sun, Yushi; Sun, Changhong; Zhu, Harry; Wincheski, Buzz

    2006-01-01

    Stress corrosion cracking in the relief radius area of a space shuttle primary reaction control thruster is an issue of concern. The current approach for monitoring of potential crack growth is nondestructive inspection (NDI) of remaining thickness (RT) to the acoustic cavities using an eddy current or remote field eddy current probe. EDM manufacturers have difficulty in providing accurate RT calibration standards. Significant error in the RT values of NDI calibration standards could lead to a mistaken judgment of cracking condition of a thruster under inspection. A tool based on eddy current principle has been developed to measure the RT at each acoustic cavity of a calibration standard in order to validate that the standard meets the sample design criteria.

  20. A Computational Study of Segmented Tungsten Rod Penetration into a Thick Steel Target Plate at High Velocities

    NASA Astrophysics Data System (ADS)

    Presnell, M.; Rajendran, A.

    2011-06-01

    This paper presents results from computational simulations of tungsten alloy segmented rod projectiles (SRP) penetrating an RHA semi-infinite target plate at high velocities. For SRP with an aspect ratio (L/D) = 1/8, a loss in penetration efficiency was seen upon successive segment impacts. Numerical simulations of a configuration in which a tungsten heavy alloy SRP penetrated a thick RHA 4340 steel at 2.6 km/s were performed using the 2006 version of the EPIC - a Lagrangian code. The configuration consisted of eight collinear impacts of discs which measured 2 mm thick and 16mm in diameter. The numerical simulations considered a range of parameters including element-particle conversion, spacing and number of fragments, failure criterion, and mesh resolution that influenced the Depth of Penetration (DOP). The EPIC results using the element-to-particle conversion capability in the EPIC code are also compared with open-literature DOP data from simulations using an Eulerian finite element code, AUTODYN for a similar configuration. The present results showed a unique phenomenon of back-flowing ejecta from the crater and fragmented segments penetrating the in-coming subsequent segment. The penetration efficiency seems to be influenced by the back-flowing ejecta. Further computational investigation considered additional simulations with an impact configuration designed to minimize the ejecta effects by using washer-shaped segments; however, the results showed insignificant improvement.

  1. Method for measuring the refractive index and the thickness of transparent plates with a lateral-shear, wavelength-scanning interferometer

    Microsoft Academic Search

    Giuseppe Coppola; Pietro Ferraro; Mario Iodice; Sergio de Nicola

    2003-01-01

    A new method for measuring simultaneously the thickness and the refractive index of a transparent plate is proposed. The method is based on a simple, variable lateral-shear, wavelength-scanning interferometer. To achieve highly accurate measurements of both refractive index n and thickness d we use several means to determine these two quantities. We finely tune a distributed-feedback diode laser light source

  2. Formation Mechanism and Suppression of Hot Cracking in Full Penetration Welding of Thick Steel Plate Using High Power CO2 Laser

    Microsoft Academic Search

    Goro Arakane; Susumu Tsukamoto; Isao Kawaguchi; Hiroshi Honda

    2005-01-01

    Full penetration laser welding has been carried out on 11, 15 and 20 mm thick steel plates. Dynamic keyhole behaviour has been observed using a micro-focused x-ray transmission imaging system to elucidate the formation mechanism of the hot cracking. Back shielding by inert gas is effective to prevent the porosity caused by supersaturation of nitrogen in the molten pool. However,

  3. Effect of Welding Atmosphere at Bottom Surface on Welding Phenomenan in Full Penetration Laser Welding of Thick Plate

    NASA Astrophysics Data System (ADS)

    Arakane, Goro; Tsukamoto, Susumu; Honda, Hiroshi; Kuroda, Seiji; Fukushima, Takeshi

    The keyhole behaviour and bubble formation were investigated in the full penetration laser welding of 11 and 15 mm thick plate with various kinds of atmosphere at the bottom side. Prevention of some defects was also attempted. Back surface atmosphere was controlled using a shielding box fixed on the sample back surface to avoid contamination from the air and also the effect of gas flow on the keyhole behaviour. A lot of bubbles were formed during welding with the back surface atmosphere of nitrogen and air. This was deduced to be caused by supersaturation of nitrogen, which was dissolved from the backside molten pool. The critical nitrogen concentration in the weld metal to form the porosity was independent of the back surface atmosphere. Oxygen enhanced the porosity formation, since the nitrogen concentration increased in the presence of oxygen. The keyhole was significantly perturbed and hot cracking occurred in the inert gas back shielding. It was shown that the keyhole stability determined by solubility of the shielding gas in the molten steel. Aluminum coating on the sample back surface was effective in preventing the porosity due to denitrification of the molten pool and hot cracking.

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

    SciTech Connect

    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.

  5. The effect of filler metal thickness on residual stress and creep for stainless-steel plate–fin structure

    Microsoft Academic Search

    Wenchun Jiang; Jianming Gong; Hu Chen; S. T. Tu

    2008-01-01

    Stainless-steel plate–fin heat exchanger (PFHE) has been used as a high-temperature recuperator in microturbine for its excellent qualities in compact structure, high-temperature and pressure resistance. Plate–fin structure, as the core of PFHE, is fabricated by vacuum brazing. The main component fins and the parting sheets are joined by fusion of a brazing alloy cladded to the surface of parting sheets.

  6. Standardization of choroidal thickness measurements using enhanced depth imaging optical coherence tomography

    PubMed Central

    Boonarpha, Nattapon; Zheng, Yalin; Stangos, Alexandros N.; Lu, Huiqi; Raj, Ankur; Czanner, Gabriela; Harding, Simon P.; Nair-Sahni, Jayashree

    2015-01-01

    AIM To describe and evaluate a standardized protocol for measuring the choroidal thickness (ChT) using enhanced depth imaging optical coherence tomography (EDI OCT). METHODS Single 9 mm EDI OCT line scans across the fovea were used for this study. The protocol used in this study classified the EDI OCT images into four groups based on the appearance of the choroidal-scleral interface and suprachoroidal space. Two evaluation iterations of experiments were performed: first, the protocol was validated in a pilot study of 12 healthy eyes. Afterwards, the applicability of the protocol was tested in 82 eyes of patients with diabetes. Inter-observer and intra-observer agreements on image classifications were performed using Cohen's kappa coefficient (?). Intraclass correlation coefficient (ICC) and Bland-Altman's methodology were used for the measurement of the ChT. RESULTS There was a moderate (?=0.42) and perfect (?=1) inter- and intra-observer agreements on image classifications from healthy eyes images and substantial (?=0.66) and almost perfect (?=0.86) agreements from diabetic eyes images. The proposed protocol showed excellent inter- and intra-observer agreements for the ChT measurements on both, healthy eyes and diabetic eyes (ICC>0.90 in all image categories). The Bland-Altman plot showed a relatively large ChT measurement agreement in the scans that contained less visible choroidal outer boundary. CONCLUSIONS A protocol to standardize ChT measurements in EDI OCT images has been developed; the results obtained using this protocol show that the technique is accurate and reliable for routine clinical practice and research. PMID:26085995

  7. Determination of thickness and elastic constants of aluminum plates from full-field wavelength measurements of single-mode narrowband Lamb waves.

    PubMed

    Deán, J Luis; Trillo, Cristina; Doval, Angel F; Fernández, José L

    2008-09-01

    A method based on fitting the theoretical dispersion curves of Lamb waves to experimental data is presented to determine the thickness and two independent elastic constants of aluminum plates a few millimeters thick. The waves are generated by means of the wedge method using a narrowband source, selecting the wedge angle and the acoustic frequency f so that mainly one mode is excited. A self-developed pulsed electronic speckle pattern interferometry system renders a two dimensional map of the out-of-plane acoustic displacement field at the plate surface, which allows an accurate measurement of the acoustic wavelength lambda(1). For any mode, the relation between lambda(1) and f depends on the three unknown parameters, so at least three experimental measurements (lambda(1i),f(i)) with different frequencies and/or different modes are required to calculate them. The suitability of different Lamb modes to determine each parameter when the others are known is studied, as well as the conditions that the experimental set of values must fulfill to calculate all three parameters. Numerous Lamb modes at different frequencies are generated in each plate, and a fitting is made based on the minimization of the error function, resulting in an accuracy better than 1%. PMID:19045639

  8. On the thermally-induced residual stresses in thick fiber-thermoplastic matrix (PEEK) cross-ply laminated plates

    NASA Technical Reports Server (NTRS)

    Hu, Shoufeng; Nairn, John A.

    1992-01-01

    An analytical method for calculating thermally-induced residual stresses in laminated plates is applied to cross-ply PEEK laminates. We considered three cooling procedures: slow cooling (uniform temperature distribution); convective and radiative cooling; and rapid cooling by quenching (constant surface temperature). Some of the calculated stresses are of sufficient magnitude to effect failure properties such as matrix microcracking.

  9. On the thermally-induced residual stresses in thick fiber-thermoplastic matrix (PEEK) cross-ply laminated plates

    SciTech Connect

    Hu, S.; Nairn, J.A.

    1992-09-01

    An analytical method for calculating thermally-induced residual stresses in laminated plates is applied to cross-ply PEEK laminates. The authors considered three cooling procedures: slow cooling (uniform temperature distribution); convective and radiative cooling; and rapid cooling by quenching (constant surface temperature). Some of the calculated stresses are of sufficient magnitude to effect failure properties such as matrix microcracking.

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

    Microsoft Academic Search

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

    2003-01-01

    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.

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

    Microsoft Academic Search

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

    2003-01-01

    SUMMARY 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

  12. Plate Tectonics

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2007-03-21

    The Plate Tectonics SciPack explores the various materials that make up Earth and the processes they undergo to provide a framework for understanding how continents are created and change over time. The focus is on Standards and Benchmarks related to Earth's layers, oceanic and continental plates and the interactions between plates.In addition to comprehensive inquiry-based learning materials tied to Science Education Standards and Benchmarks, the SciPack includes the following additional components:? Pedagogical Implications section addressing common misconceptions, teaching resources and strand maps linking grade band appropriate content to standards. ? Access to one-on-one support via e-mail to content "Wizards".? Final Assessment which can be used to certify mastery of the concepts.Learning Outcomes:Plate Tectonics: Layered Earth? Identify that Earth has layers (not necessarily name them), and that the interior is hotter and more dense than the crust.? Identify the crust as mechanically strong, and the underlying mantle as deformable and convecting.Plate Tectonics: Plates? Identify that the outermost layer of Earth is made up of separate plates.? Choose the correct speed of the motion of plates.? Identify the ocean floor as plate, in addition to the continents (to combat the common idea that only continents are plates, floating around on the oceans).? Recognize that oceans and continents can coexist on the same plate.Plate Tectonics: Plate Interactions? Identify the different interactions between plates.? Discuss what happens as a result of those interactions.Plate Tectonics: Consequences of Plate Interactions? Explain why volcanoes and earthquakes occur along plate boundaries. ? Explain how new sea floor is created and destroyed.? Describe features that may be seen on the surface as a result of plate interactions.Plate Tectonics: Lines of Evidence? Use plate tectonics to explain changes in continents and their positions over geologic time.? Provide evidence for the idea of plates, including the location of earthquakes and volcanoes, continental drift, magnetic orientation of rocks in the ocean floor, etc.

  13. Relationship of somatic cell count, physical, chemical and enzymatic properties to the bacterial standard plate count in dairy goat milk

    Microsoft Academic Search

    Chingwen Ying; Han-Tsung Wang; Jih-Tay Hsu

    2002-01-01

    Weekly milk samples, collected from individual half mammary gland of three late lactation (experiment 1) and four early lactation (experiment 2) Alpine dairy goats in second lactation, were subjected to various physical and chemical measurements to examine the relationship of the logarithm of bacterial standard plate count (SPC) to electrical conductivity (EC), neutrophils\\/lymphocytes ratio, lactate dehydrogenase (LDH), tyrosine concentration, alkaline

  14. Measurment of fluid film thickness on the valve plate in oil hydraulic axial piston pumps (Part II: Spherical design effects)

    Microsoft Academic Search

    Jiong-Ki Kim; Hyoung-Eui Kim; Yong-Bum Lee; Jae-Youn Jung; Seok-Hyung Oh

    2005-01-01

    Tribologtcal characteristics in the sliding parts of oil hydraulic piston pumps are very important in increasing overall efficiency\\u000a In this study, the fluid film between the valve plate and the cylinder block was measured by using a gap sensor and the mercury-cell\\u000a slip ring unit under real working conditions To investigate the effect of the valve shape, we designed three

  15. Correlation between standard plate count and somatic cell count milk quality results for Wisconsin dairy producers.

    PubMed

    Borneman, Darand L; Ingham, Steve

    2014-05-01

    The objective of this study was to determine if a correlation exists between standard plate count (SPC) and somatic cell count (SCC) monthly reported results for Wisconsin dairy producers. Such a correlation may indicate that Wisconsin producers effectively controlling sanitation and milk temperature (reflected in low SPC) also have implemented good herd health management practices (reflected in low SCC). The SPC and SCC results for all grade A and B dairy producers who submitted results to the Wisconsin Department of Agriculture, Trade, and Consumer Protection, in each month of 2012 were analyzed. Grade A producer SPC results were less dispersed than grade B producer SPC results. Regression analysis showed a highly significant correlation between SPC and SCC, but the R(2) value was very small (0.02-0.03), suggesting that many other factors, besides SCC, influence SPC. Average SCC (across 12 mo) for grade A and B producers decreased with an increase in the number of monthly SPC results (out of 12) that were ? 25,000 cfu/mL. A chi-squared test of independence showed that the proportion of monthly SCC results >250,000 cells/mL varied significantly depending on whether the corresponding SPC result was ? 25,000 or >25,000 cfu/mL. This significant difference occurred in all months of 2012 for grade A and B producers. The results suggest that a generally consistent level of skill exists across dairy production practices affecting SPC and SCC. PMID:24630657

  16. Standard Test Method for Water Penetration of Flat Plate Solar Collectors by Uniform Static Air Pressure Difference

    E-print Network

    American Society for Testing and Materials. Philadelphia

    1986-01-01

    1.1 This test method covers the determination of the resistance of flat plate solar collectors to water penetration when water is applied to their outer surfaces with a static air pressure at the outer surface higher than the pressure at the interior of the collector. 1.2 This test method is applicable to any flat plate solar collector. 1.3 The proper use of this test method requires a knowledge of the principles of pressure and deflection measurement. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary information is contained in Section 6.

  17. "Instantaneous superluminality" in a bimetallic wire consisting of a superconducting aluminum wire plated with a thick copper covering

    E-print Network

    R. Y. Chiao

    2010-11-14

    Maxwell's equations applied to a superconducting wire (aluminum) covered with a thick nonsuperconducting sheath (copper), in combination with the superfluid velocity equation for Cooper pairs which obeys DeWitt's minimal coupling rule, implies an instantaneous streamline flow that leads to the phenomenon of "instantaneous superluminality," in which a Cooper pair can disappear from the left end of the wire and instantaneously reappear at the right end of the wire. Relativistic causality is not violated by this superluminal phenomenon, which involves analytic, finite bandwidth waveforms whose spectrum lies below the BCS gap frequency. Experiments are proposed to test these ideas.

  18. A computational study of segmented tungsten rod penetration into a thick steel target plate at high velocities

    NASA Astrophysics Data System (ADS)

    Presnell, Michael B.; Rajendran, A. M.

    2012-03-01

    This paper presents results from numerical simulations of a configuration in which a tungsten heavy alloy SRP penetrates a thick RHA 4340 steel at 2.6 km/s using the 2006 version of the Lagrangian finite element code EPIC. Penetration experimental data show improved penetration efficiency by the segmented projectiles when compared to monolithic (single solid rod) projectiles. For SRP with an aspect ratio (L/D) = 1/8, a loss in penetration efficiency was seen upon successive segment impacts. The projectile configuration considered in this study was collinear impacts of eight successive discs which measured 2mm in thickness and 16mm in diameter. The EPIC simulations considered a range of parameters that influenced the Depth of Penetration (DOP) including element-particle conversion, spacing and number of segments, failure criteria, impact velocity, and mesh resolution. The EPIC results are also compared with open-literature DOP data from simulations using an Eulerian finite element code, AUTODYN for a similar configuration. In addition, the effects of back-flowing ejecta generated by the impact of first segment on the penetration processes of subsequent segments were studied in details. An alternate SRP design is proposed in this paper to alleviate the ejecta problem.

  19. The repair of full-thickness articular cartilage defects. Immune responses to reparative tissue formed by allogeneic growth plate chondrocyte implants

    SciTech Connect

    Kawabe, N.; Yoshinao, M. (Department of Orthopaedics, Shimane Medical School, Izumo (Japan))

    1991-07-01

    Growth plate cartilage cultivated in vitro was attached with a fibrin clot to a full-thickness articular cartilage defect on knee joints in allogeneic New Zealand rabbits. The healing of the defects was assessed by gross examination, light microscopy, and immunologic analysis for 24 weeks. Immunologic assessment of cell-mediated immunity, cytotoxicity of a humoral antibody by a 51 chromium release assay, and immunofluorescence studies were carried out. During the first two weeks following grafting, healing was excellent in 11 of the 17 defects. From three to 24 weeks, 11 of 42 defects examined had good results. Host lymphocytes had accumulated around the allograft at two to 12 weeks. Most of the implanted cartilage grown in vitro died and was replaced by fibrous tissue. The immunologic studies suggested that the implanted cartilage began to degenerate two to three weeks after implantation partially because of a humoral immune response but more importantly because of cell-mediated cytotoxicity.

  20. Enumeration of waterborne Escherichia coli with petrifilm plates: comparison to standard methods.

    PubMed

    Vail, J H; Morgan, R; Merino, C R; Gonzales, F; Miller, R; Ram, J L

    2003-01-01

    Escherichia coli is often monitored in environmental waters as an indicator of the possible presence of human pathogens associated with feces. Petrifilm E. coli/coliform count plates (3M, Minneapolis, MN), previously validated for enumerating E. coli in food, were tested for monitoring E. coli in environmental water. Escherichia coli counts in environmental water samples enumerated with Petrifilm were significantly correlated (R > 0.9; slope = 0.9-1.0; p < 0.001) with counts obtained with three commonly used methods, mTEC (Becton Dickinson, Sparks, MD), m-ColiBlue (Hach, Loveland, CO), and Colilert-18/IDEXX Quanti-Tray 2000 (IDEXX, Westbrook, ME). Blue colonies on Petrifilm plates were most reliably identified as E. coli when accompanied by gas formation, as determined by characterization of the colonies on MacConkey agar plates (PML Microbiologicals, Mississauga, ON, Canada) and by polymerase chair reaction (PCR) with E. coli-specific primers. The main disadvantage of Petrifilm plates for environmental water testing is the small volume (1 mL per sample) that can be tested; however, the plates appear to be suitable for screening and locating sites that exceed criteria for total body and partial body contact. Simplicity of use and storage, reliability, and relatively low cost make Petrifilm plates suitable for volunteer-based and educational water quality monitoring applications, particularly when used as a preliminary screening method to identify problem sites. PMID:12549577

  1. Within-plate magmatism under condition of abnormally thick sialic crust: Evidence for Proterozoic anorthosite-rapakivi granite complexes of the East-European Craton

    NASA Astrophysics Data System (ADS)

    Sharkov, Evgenii

    2010-05-01

    Mid-Proterozoic (1.8-1.5 Ga) large bimodal multistage anorthosite-rapakivi granite complexes (ARGCs) are distinct magmatic assemblages in central part of the East European Craton. ARGCs formation commenced after stabilization of the Svecofennian orogen and relics of its abnormally thick (up to 50-60 km now) crust survived here in many places. Such massifs are practically absent at the eastern part of the craton (Kola-Karelian, Volga-Urals, etc. domains) with normal thickness (~40 km) of the crust. The ARGCs formation was accompanied by emplacement of diabase, quartz porphyry and complex dike swarms. Intra-plutonic diabase dikes (Fe-Ti basalts plume-related type), intruding the rapakivi granites, are often crossed in turn by later portions of granites; injections of basaltic melt into granitic magma chambers resulted in magma mingling. It indicates that melted out occurred simultaneously in mantle and crust during ARGC formation. Geochemical peculiarities of the ARGC rocks are enrichment in alkali (especially in K), Ti, Zn, Pb, and Zr, relatively high concentrations of Be, Sn, In, Y, Nb, Rb, F, Cu, W and Mo, and sometimes - Li and U. ?Nd value, ranges from -1.2 to +1.6, and relative high Th and Zn contents, most frequently observable in anorthosites, imply that the mafic magmas were considerably contaminated by crustal components. According to geophysical data, ARGCs represent upper parts of large transcrustal systems, composed by alternation of basic and silicic rocks, which located above rises of the mantle up to 10-20 km high. Such localization of ARGCs, probably evidence that such protuberances were mantle plume heads in time, where melting of their material occurred due to adiabatic decompression. Newly-formed basaltic melts (apparently Fe-Ti basalts, similar in composition to intra-plutonic dike rocks) intruded at different depths into abnormally thick sialic crust of stabilized by then Svecofennian orogen in form of large sills and caused melting of crustal material above them. As a result, complex magmatic systems appeared here. Partial melting of the crust was the consequence of advective heating from the hot mantle magmas. Due to convection, the main heat loss during solidification was realized through roofs of basaltic sills. Consequently, extensive melting of warmed-up siliceous rocks above them would be occurred, at that thickness of newly formed granitic layer could twice exceed the thickness of basaltic sill (Huppert and Sparks, 1988). During the initial stages relatively cool crustal material at the boundary of basaltic melt and sialic roof involved in convective flows and dissolved in hot basaltic melt, which led to it's enrichment in SiO2 and Al2O3., led to predomination of plagioclase cumulates among the rocks of basic sections. Solidification of such complex chambers were began from hardening of lower basic layers; it led to domination of ascending currents in the upper silicic layer, which was favour to appearance of specific rapakivi textures in granites. ARGCs are usually associated with large Mid-Proterozoic belts of within-plate felsic volcanism, developed on all Precambrian shields on place of stabilized Paleoproterozoic orogens with thick sialic crust. From such point of view, it was the main reason for existence of such volcanism, because majority of mantle-derived mafic magmas was not reached the surface and secondary felsic melts were predominated. Evidently, ARGCs illustrate structure and processes in transitions magma chambers of such peculiar magmatic systems. Many investigators suggest that ARGCs are a part of anorthosite-mangerite-charnockite granite (AMCG) suite. However, typical AMCG complexes were commonly developed in mobile zones and undergone by deformation and high-grade metamorphism. In contrast, anorogenic ARGCs are usually localized among stabilized domains and appeared on places where Paleoproterozoic orogens completed their development. So, their tectonic settings can be described in terms of within-plate activity, distinctive from the settings of the AMCG suite.

  2. Laser induced copper plating

    Microsoft Academic Search

    A. K. Al-Sufi; H. J. Eichler; J. Salk; H. J. Riedel

    1983-01-01

    Argon laser induced plating of copper spots and lines from copper sulfate solutions on glass and phenolic resin paper has been investigated. The substrates had to be precoated with an evaporated copper film. The highest plating rates have been obtained with a small film thickness of 25 nm. Spots with a thickness up to 30 ?m were plated.

  3. Standard reference radiographs for steel castings up to 2 in. (50.8 mm) in thickness

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice describes accepted procedures for and factors that influence laboratory immersion corrosion tests, particularly mass loss tests. These factors include specimen preparation, apparatus, test conditions, methods of cleaning specimens, evaluation of results, and calculation and reporting of corrosion rates. This practice also emphasizes the importance of recording all pertinent data and provides a checklist for reporting test data. Other ASTM procedures for laboratory corrosion tests are tabulated in the Appendix. (Warning-In many cases the corrosion product on the reactive metals titanium and zirconium is a hard and tightly bonded oxide that defies removal by chemical or ordinary mechanical means. In many such cases, corrosion rates are established by mass gain rather than mass loss.) 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. This standard does not purport to address all of the safety concerns, if any, assoc...

  4. 77 FR 76842 - Exhaust Emissions Standards for New Aircraft Gas Turbine Engines and Identification Plate for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-31

    This action amends the emission standards for turbine engine powered airplanes to incorporate the standards promulgated by the United States Environmental Protection Agency (EPA) on June 18, 2012. This amendment fulfills the FAA's requirements under the Clean Air Act Amendments of 1970 to issue regulations ensuring compliance with the EPA standards. This action revises the standards for oxides of......

  5. Energy response of an imaging plate exposed to standard beta sources

    Microsoft Academic Search

    A. L. Gonzaleza; H. Li; M. Mitch; N. Tolk; D. M. Duggana

    2002-01-01

    Imaging plates (IPs) are a reusable media, which when exposed to ionizing radiation, store a latent image that can be read out with a red laser as photostimulated luminescence (PSL). They are widely used as a substitute for X-ray films for diagnostic studies. In diagnostic radiology this technology is known as computed radiography. In this work, the energy response of

  6. Comparison of central corneal thickness measurements with three new optical devices and a standard ultrasonic pachymeter.

    PubMed Central

    Bayhan, Hasan Ali; Aslan Bayhan, Seray; Can, ?zzet

    2014-01-01

    AIM To compare the RTVue spectral optical coherence tomography (SD-OCT), Sirius Scheimpflug-Placido topographer, Lenstar optical low coherence reflectometry (OLCR) and ultrasound pachymetry (USP) devices in terms of their agreement and repeatability of measuring central corneal thickness (CCT). METHODS In this prospective study, 50 eyes of 50 patients were included. Three repeated measures were obtained using SD-OCT, Scheimpflug-Placido topographer and USP and five measurements were determined with the OLCR. Bland-Altman plots were used to assess agreement among the instruments, and 95% limits of agreement (LoA) for each comparison were calculated. Intra-examiner repeatability was assessed using intraclass correlation coefficients (ICCs). RESULTS The mean CCT by SD-OCT, Scheimpflug-Placido topographer, OLCR, and USP were 525.90±34.08 µm, 525.92±34.10 µm, 530.30±35.62 µm, and 543.50±37.11 µm respectively. All 4 modalities of CCT measurements correlated closely with each other, with Pearson correlation coefficients ranging from 0.977 to 0.995. The mean differences (and upper/lower LoA) for CCT measurements were -0.05±6.77 µm (13.3/-13.3) between SD-OCT and Scheimpflug-Placido topographer, 4.38±3.79 µm (11.8/-3.1) between OLCR and SD-OCT, 4.38±6.03 µm (16.2/-7.5) between OLCR and Scheimpflug-Placido topographer, 13.20±6.46 µm (25.9/0.5) between USP and OLCR, 17.59±6.76 µm (30.8/4.3) between USP and SD-OCT, and 17.58±8.13 µm (33.5/1.6) between USP and Scheimpflug-Placido topographer. Intra-examiner repeatability was excellent for all devices with ICCs>0.98. CONCLUSION For most practical purposes, CCT measurements with the RTVue, Sirius and Lenstar can be used interchangeably. Although highly correlated, CCT measurement differences between USP and these 3 optical instruments can be significant depending on the clinical situation. PMID:24790874

  7. Standardized solar simulator tests of flat plate solar collectors. 1: Soltex collector with two transparent covers

    NASA Technical Reports Server (NTRS)

    Simon, F.

    1975-01-01

    A Soltex flat plate solar collector was tested with a solar simulator for inlet temperatures of 77 to 201 F, flux levels of 240 and 350 Btu/hr-sq ft, a collant flow rate of 10.5 lb/hr sq ft, and incident angles of 0 deg, 41.5 deg, and 65.2 deg. Collector performance is correlated in terms of inlet temperature, flux level, and incident angle.

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

    NASA Astrophysics Data System (ADS)

    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 ? (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.

  9. Angular shear plate

    DOEpatents

    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.

  10. 78 FR 63015 - Exhaust Emissions Standards for New Aircraft Gas Turbine Engines and Identification Plate for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    The FAA is making technical changes to a final rule published in the Federal Register on December 31, 2012. That final rule amended the emission standards for certain turbine engine powered airplanes to incorporate the standards promulgated by the United States Environmental Protection Agency (EPA) on June 18, 2012. The final rule contained six minor technical errors: One in the authority......

  11. 78 FR 63017 - Exhaust Emissions Standards for New Aircraft Gas Turbine Engines and Identification Plate for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    On December 31, 2012, the FAA published a final rule with a request for comments amending the emission standards for turbine engine powered airplanes to incorporate the standards that were promulgated by the United States Environmental Protection Agency (EPA) on June 18, 2012. The FAA's final rule fulfilled its requirements under the Clean Air Act Amendments of 1970 to issue regulations ensuring......

  12. Chromium ion plating studies for enhancement of bearing lifetime

    NASA Technical Reports Server (NTRS)

    Davis, J. H.

    1982-01-01

    Six 440-C hardened stainless steel roller bearing test rods were ion plated with various chromium films of thicknesses from .2 microns to 7 microns. The thinner (approximately .2 microns) coating sample had 3 times the fatigue life of the unplated (standard) specimens. Contrastingly, the samples having thicker coatings (several microns) had short fatigue lives (about 3% of the unplated standard).

  13. Toward Microbioreactor Arrays: A Slow-Responding Oxygen Sensor for Monitoring of Microbial Cultures in Standard 96-Well Plates.

    PubMed

    Glauche, Florian; John, Gernot T; Arain, Sarina; Knepper, Andreas; Neubauer, Antje; Goelling, Detlef; Lang, Christine; Violet, Norman; King, Rudibert; Neubauer, Peter

    2015-08-01

    In this study, a slow-responding chemo-optical sensor for dissolved oxygen (DO) integrated into a 96-well plate was developed. The slow response time ensures that the measured oxygen value does not change much during plate transport to the microplate reader. The sensor therefore permits at-line DO measurement of microbial cultures. Moreover, it eliminates the necessity of individual optical measurement systems for each culture plate, as many plates can be measured successively. Combined with the 96-well format, this increases the experimental throughput enormously. The novel sensor plate (Slow OxoPlate) consists of fluorophores suspended in a polymer matrix that were placed into u-bottom 96-well plates. Response time was measured using sodium sulfite, and a t90 value of 9.7 min was recorded. For application, DO values were then measured in Escherichia coli and Saccharomyces cerevisiae cultures grown under fed-batch-like conditions. Depending on the DO sensor's response time, different information on the oxygenation state of the culture plate was obtained: a fast sensor variant detects disturbance through sampling, whereas the slow sensor indicates oxygen limitation during incubation. A combination of the commercially available OxoPlate and the Slow OxoPlate enables operators of screening facilities to validate their cultivation procedures with regard to oxygen availability. PMID:25720599

  14. Medial submuscular plating of the femur in a series of paediatric patients: a useful alternative to standard lateral techniques.

    PubMed

    Nayagam, S; Davis, B; Thevendran, G; Roche, A J

    2014-01-01

    We describe the technique and results of medial submuscular plating of the femur in paediatric patients and discuss its indications and limitations. Specifically, the technique is used as part of a plate-after-lengthening strategy, where the period of external fixation is reduced and the plate introduced by avoiding direct contact with the lateral entry wounds of the external fixator pins. The technique emphasises that vastus medialis is interposed between the plate and the vascular structures. A total of 16 patients (11 male and five female, mean age 9.6 years (5 to 17)), had medial submuscular plating of the femur. All underwent distraction osteogenesis of the femur with a mean lengthening of 4.99 cm (3.2 to 12) prior to plating. All patients achieved consolidation of the regenerate without deformity. The mean follow-up was 10.5 months (7 to 15) after plating for those with plates still in situ, and 16.3 months (1 to 39) for those who subsequently had their plates removed. None developed a deep infection. In two patients a proximal screw fractured without loss of alignment; one patient sustained a traumatic fracture six months after removal of the plate. Placing the plate on the medial side is advantageous when the external fixator is present on the lateral side, and is biomechanically optimal in the presence of a femoral defect. We conclude that medial femoral submuscular plating is a useful technique for specific indications and can be performed safely with a prior understanding of the regional anatomy. PMID:24395325

  15. Plating To Reinforce Welded Joints

    NASA Technical Reports Server (NTRS)

    Otousa, J. E.

    1982-01-01

    Electrodeposition used to strengthen welded joints gouged, nicked, or suffered other mechanical damage. Plating cell, typically of acrylic plastic such as poly (Methylmetacrylate), is assembled around part to be plated. Areas not to be plated are masked with plater's tape. Weld area is plated in standard nickel-plating process.

  16. Comparison of Long-Wavelength Residual Elevation and Free Air Gravity Anomalies in the North Atlantic and Possible Implications for the Thickness of the Lithospheric Plate

    Microsoft Academic Search

    John G. Sclater; Lawrence A. Lawver; Barry Parsons

    1975-01-01

    For most oceans the basic feature of the elevation of ridges is a uniform relation between subsidence and age directly associated with the creation and cooling of the oceanic plate. In the North Atlantic we show that superimposed upon this subsidence curve are long-wavelength (>400-km) residual elevation anomalies up to 1200-m amplitude between 50øN and 10øN that are linearly related

  17. Comparison of a novel ColiPlateTM kit and the standard membrane filter technique for enumerating total coliforms and Escherichia coli bacteria in water

    Microsoft Academic Search

    Ran Lifshitz; Renu Joshi

    1998-01-01

    The new ColiPlate (CP) kit was evaluated comparatively with the standard membrane filter (MF) technique for enumerating total coliforms and Escherichia coli in water. In testing natural water samples, good correlations were observed for enumerating total coliforms (R2 = 0.84) and E. coli (R2 = 0.95). However, counts of E. coli population density estimated by CP were 47% higher than

  18. Hypervelocity plate acceleration

    SciTech Connect

    Marsh, S.P.; Tan, T.H.

    1991-01-01

    Shock tubes have been used to accelerate 1.5-mm-thick stainless steel plates to high velocity while retaining their integrity. The fast shock tubes are 5.1-cm-diameter, 15.2-cm-long cylinders of PBX-9501 explosive containing a 1.1-cm-diameter cylindrical core of low-density polystyrene foam. The plates have been placed directly in contact with one face of the explosive system. Plane-wave detonation was initiated on the opposite face. A Mach disk was formed in the imploding styrofoam core, which provided the impulse required to accelerate the metal plate to high velocity. Parametric studies were made on this system to find the effect of varying plate metal, plate thickness, foam properties, and addition of a barrel. A maximum plate velocity of 9.0 km/s has been observed. 6 refs., 17 figs.

  19. Plate Tectonics: Plate Interactions

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2006-11-01

    This Science Object is the fourth of five Science Objects in the Plate Tectonic SciPack. It identifies the events that may occur and landscapes that form as a result of different plate interactions. The areas along plate margins are active. Plates pushing against one another can cause earthquakes, volcanoes, mountain formation, and very deep ocean trenches. Plates pulling apart from one another can cause smaller earthquakes, magma rising to the surface, volcanoes, and oceanic valleys and mountains from sea-floor spreading. Plates sliding past one another can cause earthquakes and rock deformation. Learning Outcomes:? Explain why volcanoes and earthquakes occur along plate boundaries. ? Explain how new sea floor is created and destroyed.? Describe features that may be seen on the surface as a result of plate interactions.

  20. A comparison of unglazed flat plate liquid solar collector thermal performance using the ASHRAE Standard 96-1980 and modified BSE test procedures

    NASA Astrophysics Data System (ADS)

    Jenkins, J. P.; Reed, K. A.

    1982-05-01

    The report reviews the BSE procedure and summarizes the ASHRAE Standard 96-1980 for testing unglazed solar collectors. The ASHRAE procedure consists exclusively of outdoor testing, whereas the BSE procedure requires a combination of outdoor and indoor testing (no irradiation) to determine the collector optical and thermal loss characteristics, respectively. Two unglazed flat plate liquid solar collectors were tested according to ASHRAE Standard 96-1980 and BSE procedures and the results compared. During the indoor BSE thermal loss tests blowers were used to simulate winds of 0-3.9 m/s(0-8.72 mi/hr) to investigate the wind effect upon collector thermal losses.

  1. Within-plate magmatism under condition of abnormally thick sialic crust: Evidence for Proterozoic anorthosite-rapakivi granite complexes of the East-European Craton

    Microsoft Academic Search

    Evgenii Sharkov

    2010-01-01

    Mid-Proterozoic (1.8-1.5 Ga) large bimodal multistage anorthosite-rapakivi granite complexes (ARGCs) are distinct magmatic assemblages in central part of the East European Craton. ARGCs formation commenced after stabilization of the Svecofennian orogen and relics of its abnormally thick (up to 50-60 km now) crust survived here in many places. Such massifs are practically absent at the eastern part of the craton

  2. The Dielectric Characteristics of Screen Printed SrTiO3Epoxy Composite Thick Films on the Cu Plate PCB Substrates

    Microsoft Academic Search

    Yong-Su Ham; Jung-Hyuk Koh

    2009-01-01

    Novel electronic devices require higher performance and miniaturization. Due to the increased demands for the high density of passive components in the mobile system, integration of passive components in the inner layers of multi-layer substrates has been actively investigated.In this paper, we studied on SrTiO3-epoxy composites thick films for embedded capacitor applications. SrTiO3-epoxy composites were employed to explore its feasibilities

  3. Standardized performance tests of collectors of solar thermal energy - A flat-plate copper collector with parallel mylar striping

    NASA Technical Reports Server (NTRS)

    Johnson, S. M.

    1976-01-01

    Basic test results are reported for a flat plate solar collector whose performance was determined in a solar simulator. The collector was tested over ranges of inlet temperatures, fluxes and one coolant flow rate. Collector efficiency is correlated in terms of inlet temperature and flux level.

  4. Split-Thickness Skin Grafts Remain the Gold Standard for the Closure of Large Acute and Chronic Wounds

    PubMed Central

    Simman, Richard; Phavixay, Laemthong

    2012-01-01

    Healing large chronic and acute wounds is a challenging task for wound care providers. It requires numerous visits and frequent dressing changes and often involves expensive therapeutic modalities. Our primary and ultimate goal is to heal these wounds as quickly as possible. In a prepared wound bed, covered with granulation tissue and free of infection, skin graft is the gold standard procedure to achieve this goal. One should keep in mind that not all patients are good candidates for surgery. PMID:24525612

  5. Channel plate for DNA sequencing

    DOEpatents

    Douthart, R.J.; Crowell, S.L.

    1998-01-13

    This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface. 15 figs.

  6. Channel plate for DNA sequencing

    DOEpatents

    Douthart, Richard J. (Richland, WA); Crowell, Shannon L. (Eltopia, WA)

    1998-01-01

    This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface.

  7. Plate TectonicsPlate Tectonics Plate TectonicsPlate Tectonics

    E-print Network

    Siebel, Wolfgang

    Plate TectonicsPlate Tectonics #12;Plate TectonicsPlate Tectonics · Lithosphere ­ strong, rigid, transform boundaries ­ travel 1 to 11 cm/yr relative to one another #12;14 tectonic plates today #12;Mid asthenosphere that flows · 8 large lithospheric plates and 6 smaller ones ­ separated by divergent, convergent

  8. Standard reference radiographs for steel fusion welds

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This standard provides reference radiographs for steel fusion welds that contain typical discontinuities with varying severity levels in different thicknesses of material. The reference radiograph films are an adjunct to this standard and must be purchased separately from ASTM International if needed. 1.2 There are three volumes of reference radiographs based on seven nominal weld thicknesses as follows: Vol ISet of 16 plates (81/2 by 11 in.) covering base material up to and including ¼ in. (6.4 mm) in thickness. Vol IISet of 29 plates (8½ by 11 in.) covering base material over ¼ to and including 3 in. (6.4 to 76 mm) in thickness. Vol IIISet of 32 plates (8 ½ by 11 in.) covering base material over 3 to including 8 in. (76 to 203 mm) in thickness. 1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.4 This standard does not pur...

  9. Aluminum transfer method for plating plastics

    NASA Technical Reports Server (NTRS)

    Goodrich, W. D.; Stalmach, C. J., Jr.

    1977-01-01

    Electroless plating technique produces plate of uniform thickness. Hardness and abrasion resistance can be increased further by heat treatment. Method results in seamless coating over many materials, has low thermal conductivity, and is relatively inexpensive compared to conventional methods.

  10. Optimal parameters of sandwich composite plates

    NASA Astrophysics Data System (ADS)

    Kriutchenko, V. E.

    1992-12-01

    A method is proposed for calculating the optimal parameters of sandwich plates of specified stiffness loaded in flexure. The objective function is the plate mass, with the elastic and inertial characteristics of the layer used as the optimization parameters. An analytical relationship is established between the normalized thickness of a plate and its mass; an expression is obtained for the optimal plate thickness, which corresponds to the minimum mass for a fixed cylindrical stiffness.

  11. Channel plating. Final report

    Microsoft Academic Search

    1985-01-01

    A process was developed for fabricating printed wiring boards with dense (closely spaced, narrow conductors) circuitry. The characteristics of epoxy-glass printed wiring board laminate clad with copper thicknesses of 0.005, 0.009, 0.013, 0.018, and 0.036 mm were compared. The circuitry was defined by a comparatively thick dry-film photoresist which effectively confines the subsequent copper plating for metallization of through-holes) within

  12. Plate motion

    SciTech Connect

    Gordon, R.G. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

    1991-01-01

    The motion of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global model of current plate motions, diffuse plate boundaries and the oceanic lithosphere, the relation between plate motions and distributed deformations, accelerations and the steadiness of plate motions, the distribution of current Pacific-North America motion across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.

  13. Sub-Plate Overlap Code Documentation

    NASA Technical Reports Server (NTRS)

    Taff, L. G.; Bucciarelli, B.; Zarate, N.

    1997-01-01

    An expansion of the plate overlap method of astrometric data reduction to a single plate has been proposed and successfully tested. Each plate is (artificially) divided into sub-plates which can then be overlapped. This reduces the area of a 'plate' over which a plate model needs to accurately represent the relationship between measured coordinates and standard coordinates. Application is made to non-astrographic plates such as Schmidt plates and to wide-field astrographic plates. Indeed, the method is completely general and can be applied to any type of recording media.

  14. Plate Tectonics

    NSDL National Science Digital Library

    Mrs. Rohlfing

    2011-02-03

    Students will go over the main points of plate tectonics, including the theory of continental drift, different types of plate boundaries, seafloor spreading, and convection currents. We have been spending time learning about plate tectonics. We have discussed the theory of continental drift, we have talked about the different types of plate boundaries, we have also learned about seafloor spreading and convection currents. Plate Boundary Diagram Now is your chance ...

  15. Vibrations and Dynamic Stability of Cellular Plate

    NASA Astrophysics Data System (ADS)

    Magnucka-Blandzi, Ewa

    2008-09-01

    Subject of the paper is a circular plate under radial compression. The plate is made of the metal foam. Properties of the plate vary across its thickness. Middle plane of the plate is its symmetry plane. The field of displacement of any cross section of the plate, the nonlinear components of the strain field and the stress field are defined. Basing on the Hamilton principle a system of differential equations of dynamic stability of the plate is formulated. This basic system of equations is approximately solved. The results of the studies are compared to homogeneous circular plate and shown in Figures.

  16. Heat transfer from interrupted plates

    NASA Astrophysics Data System (ADS)

    Zelenka, R. L.; Loehrke, R. I.

    1983-02-01

    Heat transfer coefficients were measured in single and multiple flat plates equipped with interior heating elements and immersed in low Re flows in a wind tunnel. The plates were located successively in the tunnel and spanned the width of the channel. Attention was initially given to blunt leading edges, which were gradually reshaped in order to study various flow separation conditions over the course of the trials. Each plate was heated to 6 C over room temperature. The average value of a heat transfer coefficient for a single plate was determined to depend on the plate length and thickness, and may be inhibited by the leading edge separation bubble in the case of a blunt leading edge. Higher Re enhances the value of the coefficient. Turbulence induced by the presence of the first plate was observed to enhance heat transfer from the second plate.

  17. Hypervelocity impact on shielded plates

    NASA Technical Reports Server (NTRS)

    Smith, James P.

    1993-01-01

    A ballistic limit equation for hypervelocity impact on thin plates is derived analytically. This equation applies to cases of impulsive impact on a plate that is protected by a multi-shock shield, and it is valid in the range of velocity above 6 km/s. Experimental tests were conducted at the NASA Johnson Space Center on square aluminum plates. Comparing the center deflections of these plates with the theoretical deflections of a rigid-plastic plate subjected to a blast load, one determines the dynamic yield strength of the plate material. The analysis is based on a theory for the expansion of the fragmented projectile and on a simple failure criterion. Curves are presented for the critical projectile radius versus the projectile velocity, and for the critical plate thickness versus the velocity. These curves are in good agreement with curves that have been generated empirically.

  18. Fuel cell end plate structure

    DOEpatents

    Guthrie, Robin J. (East Hartford, CT); Katz, Murray (Newington, CT); Schroll, Craig R. (Glastonbury, CT)

    1991-04-23

    The end plates (16) of a fuel cell stack (12) are formed of a thin membrane. Pressure plates (20) exert compressive load through insulation layers (22, 26) to the membrane. Electrical contact between the end plates (16) and electrodes (50, 58) is maintained without deleterious making and breaking of electrical contacts during thermal transients. The thin end plate (16) under compressive load will not distort with a temperature difference across its thickness. Pressure plate (20) experiences a low thermal transient because it is insulated from the cell. The impact on the end plate of any slight deflection created in the pressure plate by temperature difference is minimized by the resilient pressure pad, in the form of insulation, therebetween.

  19. Plate Boundaries

    NSDL National Science Digital Library

    This site provides information on plate boundaries, which are found at the edge of the lithospheric plates and are of three types: convergent, divergent and conservative. Wide zones of deformation are usually characteristic of plate boundaries because of the interaction between two plates. The three boundaries are characterized by their distinct motions which are described in the text and depicted with block diagram illustrations, all of which are animated. There are also two maps that show the direction of motion of the plates. Active links lead to more information on plate tectonics.

  20. Quantum levitation of a thin magnetodielectric plate on a metallic plate using the repulsive Casimir force

    NASA Astrophysics Data System (ADS)

    Inui, Norio

    2012-04-01

    Levitation of a thin magnetodielectric plate on a metallic plate by using the repulsive Casimir force is theoretically considered. If the permittivity of the metallic plate near zero frequency is expressed by a plasma model and the static permeability of the magnetodielectric plate is higher than its static permittivity, the Casimir force between the magnetodielectric plate and the metallic plate changes from attractive to repulsive as the separation between them increases. Furthermore, as the thickness of the magnetodielectric plate is decreased, the attractive component of the Casimir force decreases more than the repulsive one. This effect generates a larger repulsive Casimir force as compared with that between the plates having infinite thickness. Combined with the effect of decreasing the weight of the plate, this might enable a thin plate to levitate in vacuum. The height of quantum levitation is evaluated for a combination of yttrium iron garnet and gold.

  1. Plate Tectonics

    NSDL National Science Digital Library

    Smoothstone

    This interactive Flash explores plate tectonics and provides an interactive map where users can identify plate boundaries with name and velocities as well as locations of earthquakes, volcanoes, and hotspots. The site also provides animations and supplementary information about plate movement and subduction. This resource is a helpful overview or review for introductory level high school or undergraduate physical geology or Earth science students.

  2. Plate Tectonics

    NSDL National Science Digital Library

    Mrs. Walls

    2011-01-30

    Create a poster all about Plate Tectonics! Directions: Make a poster about Plate Tectonics. (20 points) Include at least (1) large picture (15 points) on your poster complete with labels of every part (10 points). (15 points) Include at least three (3) facts about Plate Tectonics. (5 points ...

  3. Pixelated neutron image plates

    NASA Astrophysics Data System (ADS)

    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.

  4. Tectonic Plates and Plate Boundaries

    NSDL National Science Digital Library

    WGBH Educational Foundation

    2005-12-17

    This interactive activity adapted from NASA features world maps that identify different sections of the Earth's crust called tectonic plates. The locations of different types of plate boundaries are also identified, including convergent, divergent, and transform boundaries.

  5. Standardizing

    NSDL National Science Digital Library

    This page, created by Statisical Literacy.com, contains a short article on Simpson'Â?Â?s Paradox with an example of how standardizing changes the results. It also contains links to other "real world" articles on Simpson'Â?Â?s Paradox, including a newspaper article illustrating that this topic is timely. The site features a few graphs to help better represent the concept. Overall, this is a brief but useful explanation of this concept.

  6. Plating Processes Utilizing High Intensity Acoustic Beams

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C. (Inventor); Denofrio, Charles (Inventor)

    2002-01-01

    A system and a method for selective plating processes are disclosed which use directed beams of high intensity acoustic waves to create non-linear effects that alter and improve the plating process. The directed beams are focused on the surface of an object, which in one embodiment is immersed in a plating solution, and in another embodiment is suspended above a plating solution. The plating processes provide precise control of the thickness of the layers of the plating, while at the same time, in at least some incidents, eliminates the need for masking.

  7. Bipolar battery plate

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1987-01-01

    A liquid-impermeable plate (10) having through-plate conductivity with essentially zero resistance comprises an insulator sheet (12) having a series of spaced perforations (14) each of which contains a metal element (16) sealingly received into the perforation (14). A low-cost plate can readily be manufactured by punching a thermoplastic sheet (40) such as polypropylene with a punching tool (52), filling the apertures with led spheres (63) having a diameter smaller than the holes (50) but larger than the thickness of the sheet, sweeping excess spheres (62) off the sheet with a doctor blade (60) and then pressing a heated platen (74) onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar (4) sealing the metal into the sheet.

  8. 30 CFR 20.13 - Approval plate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MINE LAMPS OTHER THAN STANDARD CAP LAMPS § 20.13 Approval plate. The manufacturer shall attach, stamp, or mold an approval plate on the...

  9. 30 CFR 20.13 - Approval plate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MINE LAMPS OTHER THAN STANDARD CAP LAMPS § 20.13 Approval plate. The manufacturer shall attach, stamp, or mold an approval plate on the...

  10. Plate Tectonics

    NSDL National Science Digital Library

    2006-01-01

    In this lesson, students are introduced to the theory of plate tectonics and explore how the theory was developed and supported by evidence. Through class discussion, videos, and activities, students seek connections between tectonic activity and geologic features and investigate how the theory of plate tectonics evolved.

  11. Effective elastic thickness and crustal thickness variations in west central Africa inferred from gravity data

    SciTech Connect

    Poudjom Djomani, Y.H.; Nnange, J.M.; Ebinger, C.J. [Univ. of Leeds (United Kingdom)] [and others] [Univ. of Leeds (United Kingdom); and others

    1995-11-10

    This report uses coherence function analysis of 32,000 gravity and topography points from Cameroon west Africa to determine the relationship between the plate tectonic and flexural rigidity of the lithosphere in terms of the crusts effective elastic thickness.

  12. Turbulent thermal convection over grooved plates

    NASA Astrophysics Data System (ADS)

    Stringano, G.; Pascazio, G.; Verzicco, R.

    2006-06-01

    Direct numerical simulations of thermal convection over grooved plates are presented and discussed, in comparison with the standard flat-plate case, in order to gain a better understanding of the altered near-wall dynamics and of the enhancement of the heat transfer. The simulations are performed in a cylindrical cell of aspect-ratio (diameter over cell height) ? = 1/2 at fixed Prandtl number Pr = 0.7 with the Rayleigh number Ra ranging from 2 × 106 to 2 × 1011. The results show an increase of heat transfer, or in non-dimensional form the Nusselt number Nu when the mean thermal boundary-layer thickness becomes smaller than the groove height, in agreement with earlier experimental investigations available from the literature. The present increase, however, results in a steeper power law of the Nu vs. Ra law rather than a simple upward shift of the Nu law of the flat plate. This finding agrees with some studies, but it is at variance with others. Possible causes for this difference are discussed with the help of an electrical analogy.

  13. Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.

    PubMed

    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. PMID:23714123

  14. Peen plating

    NASA Technical Reports Server (NTRS)

    Babecki, A. J. (inventor); Haehner, C. L.

    1973-01-01

    A process for metal plating which comprises spraying a mixture of metallic powder and small peening particles at high velocity against a surface is described. The velocity must be sufficient to impact and bond metallic powder onto the surface. In the case of metal surfaces, the process has as one of its advantages providing mechanical working (hardening) of the surface simultaneously with the metal plating.

  15. Plate Tectonics

    NSDL National Science Digital Library

    This data tip from Bridge, the Ocean Sciences Education Teacher Resource Center archive, includes a variety of educational sites to visit on plate tectonic theory. Learners can use underwater earthquake data to identify plate boundaries with links to the National Oceanic and Atmospheric Administration's Acoustic Monitoring Program Ocean Seismicity data. Data from the Northeast Pacific, eastern Equatorial Pacific, and North Atlantic are examined in more detail.

  16. Stability optimization of laminated composite plates

    NASA Technical Reports Server (NTRS)

    Hirano, Y.

    1980-01-01

    The optimum design of plates with orthotropic layers under axial compression and shear is discussed. The plates considered are the laminates of N orthotropic layers whose principal material axes coincide with the plate axes. Each layer is assumed to have the same thickness and an equal number of fibers in the direction of + alpha sub i and - alpha sub i with respect to the plate axis. The fiber directions which give the highest axial buckling stress and the highest shear buckling stress are found by utilizing a mathematical optimization technique for various aspect ratios of the plates. Inhomogeneity in the direction of the plate thickness (stacking sequence) is taken into account in this analysis.

  17. A slotted orifice plate used as a flow measurement device 

    E-print Network

    Macek, Michael Lee

    1993-01-01

    The standard orifice plate is used extensively by the natural gas industry for the metering of fuel. Because of the costs associated with errors in flow measurement inherent with the use of a standard orifice plate, any improvements upon...

  18. Buckling Analysis of Rectangular Plates With Holes

    NASA Technical Reports Server (NTRS)

    Nemeth, M. P.

    1987-01-01

    BUCKO is computer program developed to predict buckling of rectangular compression-loaded orthotropic plate with centrally located cutout. Plate assumed balanced, symmetric laminate of uniform thickness. Cutout shape elliptical, circular, rectangular, or square. Package includes sample data demonstrating essence of program and ease of use. Written in FORTRAN V.

  19. Advances and trends in plate buckling research

    NASA Technical Reports Server (NTRS)

    Leissa, A.

    1982-01-01

    Advances and current trends in plate bucklin research are summarized. The field is divided into three parts: (1) classical buckling studies, including plates of rectangular, circular and other shapes; (2) classical complicating effects, including elastic foundation, anisotropic material, variable thickness, shear deformation and nonhomogeneous material; and (3) nonclassical considerations, including postbuckling, imperfections, parametric excitation, follower forces, magnetoelastic buckling and inelastic buckling.

  20. Thermal Divergence of Supersonic Functionally Graded Plates

    Microsoft Academic Search

    S. Ahmad Fazelzadeh; M. Hosseini; H. Madani

    2011-01-01

    This paper presents the thermal divergence analysis of supersonic plates made of functionally graded materials. The governing equations are based on the first-order shear deformation theory. The effects of steady aerodynamic pressure loadings in conjunction with elevated temperature are evaluated. It is assumed that the plate is subjected to uniform and linear temperature distributions across the thickness. The material properties

  1. Vibrations of circular steel plates with damping

    E-print Network

    Sheth, Prafulchandra Naginlal

    1967-01-01

    Bridge Meter Amplifier and Oscilloscope Exciter With Housing Master Control Panel ~ ~ ~ 9 Frequencies vs Plate Thickness For Single Plates With Different Nodal Shapes . . . . . . . . . . . . . . . . . 31 10 Effects Of Gaskets On Different Nodal... used. Circular steel plates and laminations of these with unbonded rubber gaskets were vibrated and the resulting node pattern, frequencies and ampli- tudes were recorded in tables. A study was made from the collected *Numbers in parentheses refer...

  2. Aluminium oxide microchannel plates

    NASA Astrophysics Data System (ADS)

    Delendik, K.; Emeliantchik, I.; Litomin, A.; Rumyantsev, V.; Voitik, O.

    2003-09-01

    Microchannel electron multipliers of a new type are proposed - anodic alumina microchannel plates (MCP). They implement the conventional concept of lead glass microchannel plate with a new material - anodic aluminium oxide. Anodic alumina is a very suitable material for microchannel plates due to presense of natural microchannels. Diameters of these channels lie in the range of 0.02 - 0.5 ?m, channels of greater diameter can be easily produced by means of additional processing based on the presence of intrinsic microchannel structure. We have produced MCPs with channel diameters 0.2 - 8 ?m and thickness 40 - 150 ?m. We have also developed two methods of deposition of conductive and emissive films inside MCP channels: plasma sputtering and liquid-phase deposition from metallo-organic precursors. MCP samples with NiO?MgO and Cu?CuO?BeO?MgO coatings have demonstrated promising results. Alumina MCP potentially have serious advantages over traditional lead glass MCP: they are much cheaper, large area plates (hundreds of cm2) can be easily produced, spatial resolution can be much better (due to smaller channel diameter).

  3. Bipolar battery plate

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1985-01-01

    A liquid-impermeable plate (10) having throughplate conductivity with essentially zero resistance comprises an insulator sheet (12) having a series of spaced perforations (14) each of which contains a metal element (16) sealingly received into the perforation (14). A low-cost plate can readily be manufactured by punching a thermoplastic sheet (40) such as polypropylene with a punching tool (52), filling the apertures with lead spheres (63) having a diameter smaller than the holes (50) but larger than the thickness of the sheet, sweeping excess spheres (62) off the sheet with a doctor blade (60) and then pressing a heated platen (74) onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar (4) sealing the metal into the sheet.

  4. Bipolar battery plate

    SciTech Connect

    Rowlette, J. J.

    1985-09-17

    A liquid-impermeable plate having throughplate conductivity with essentially zero resistance comprises an insulator sheet having a series of spaced perforations each of which contains a metal element sealingly received into the perforation. A low-cost plate can readily be manufactured by punching a thermoplastic sheet such as polypropylene with a punching tool, filling the apertures with lead spheres having a diameter smaller than the holes but larger than the thickness of the sheet, sweeping excess spheres off the sheet with a doctor blade and then pressing a heated platen onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar sealing the metal into the sheet.

  5. Martian plate tectonics

    NASA Astrophysics Data System (ADS)

    Sleep, N. H.

    1994-03-01

    The northern lowlands of Mars have been produced by plate tectonics. Preexisting old thick highland crust was subducted, while seafloor spreading produced thin lowland crust during late Noachian and Early Hesperian time. In the preferred reconstruction, a breakup margin extended north of Cimmeria Terra between Daedalia Planum and Isidis Planitia where the highland-lowland transition is relatively simple. South dipping subduction occured beneath Arabia Terra and east dipping subduction beneath Tharsis Montes and Tempe Terra. Lineations associated with Gordii Dorsum are attributed to ridge-parallel structures, while Phelegra Montes and Scandia Colles are interpreted as transfer-parallel structures or ridge-fault-fault triple junction tracks. Other than for these few features, there is little topographic roughness in the lowlands. Seafloor spreading, if it occurred, must have been relatively rapid. Quantitative estimates of spreading rate are obtained by considering the physics of seafloor spreading in the lower (approx. 0.4 g) gravity of Mars, the absence of vertical scarps from age differences across fracture zones, and the smooth axial topography. Crustal thickness at a given potential temperature in the mantle source region scales inversely with gravity. Thus, the velocity of the rough-smooth transition for axial topography also scales inversely with gravity. Plate reorganizations where young crust becomes difficult to subduct are another constraint on spreading age. Plate tectonics, if it occurred, dominated the thermal and stress history of the planet. A geochemical implication is that the lower gravity of Mars allows deeper hydrothermal circulation through cracks and hence more hydration of oceanic crust so that more water is easily subducted than on the Earth. Age and structural relationships from photogeology as well as median wavelength gravity anomalies across the now dead breakup and subduction margins are the data most likely to test and modify hypotheses about Mars plate tectonics.

  6. Cadmium plating replacements

    NASA Technical Reports Server (NTRS)

    Nelson, Mary J.; Groshart, Earl C.

    1995-01-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  7. Locking plate technology: current concepts.

    PubMed

    Greiwe, R Michael; Archdeacon, Michael T

    2007-01-01

    The management of fractures with traditional plating techniques has undergone a paradigm shift over the past 20 years. For many fractures, anatomic reduction using a dynamic compression plate has been the gold standard. However, minimally invasive approaches combined with biologically friendly internal fixation have become accepted methods of complex fracture treatment. The orthopedic literature has demonstrated advantages when comparing locking plate techniques with traditional compression plating techniques, particularly in fractures about the knee. The advantages of locking plates apply most directly to cases of highly comminuted fractures, unstable metadiaphyseal segments, and osteoporotic fractures. The biomechanical properties of locking plates have distinguished and defined their clinical use compared to traditional plates. A thorough understanding of these properties will assist the orthopedic surgeon in choosing the appropriate construct when faced with a difficult fracture. Compression plating requires absolute stability for bone healing. In contrast, locking plates function as "internal fixators" with multiple anchor points. This type of fixed-angle device converts axial loads across the bone to compressive forces across fracture sites, minimizing gap length and strain. The strain theory demonstrates that anatomic reduction is not required for bone healing, and that tolerable strain (2%-10%) can promote secondary bone healing. Callus formation is further promoted when biologically friendly surgical approaches are combined with locking plate "internal fixators". In contrast, conventional plates function by creating an environment where primary bone healing occurs. This plate provides "absolute rigidity" and requires anatomic reduction fixed in compression. Primary bone healing occurs in this manner. In highly comminuted, segmentally deficient, or porotic bone, bone quality is poor and "absolute rigidity" does not exist. Furthermore, soft-tissue stripping adds a biologic insult to the poor bone quality. These disadvantages may lead to poor outcomes such as nonunion, implant failure, malunion, or even infection. These disadvantages remain theoretical, as no prospective studies clearly demonstrate a difference between plating methods in difficult metadiaphyseal or osteoporotic fractures. However, the overwhelming biomechanical evidence has led to a more biologically friendly approach to these fractures. The indications for use of locking plates are evolving. The literature demonstrates low rates of nonunion and overall complication rates with locking plates in difficult metaphyseal and diaphyseal fractures. Anatomic reduction of the articular surface remains paramount. Hybrid techniques that combine the benefits of compression plate fixation with the biological and biomechanical advantages of locking plates are the most likely end result of current locking plate applications. PMID:17288090

  8. Shear bands and cracking of metallic glass plates in bending

    Microsoft Academic Search

    R. D. Conner; W. L. Johnson; W. D. Nixa; W. D. Nix

    2006-01-01

    The thickness dependence of yielding and fracture of metallic glass plates subjected to bending is considered in terms of the shear band processes responsible for these properties. We argue that the shear band spacing ~and length! scales with the thickness of the plate because of strain relaxation in the vicinity of the shear band at the surface. This is consistent

  9. Shear bands and cracking of metallic glass plates in bending

    Microsoft Academic Search

    R. D. Conner; W. L. Johnson; N. E. Paton; W. D. Nix

    2003-01-01

    The thickness dependence of yielding and fracture of metallic glass plates subjected to bending is considered in terms of the shear band processes responsible for these properties. We argue that the shear band spacing (and length) scales with the thickness of the plate because of strain relaxation in the vicinity of the shear band at the surface. This is consistent

  10. Vibrations of twisted cantilevered plates - Experimental investigation

    NASA Technical Reports Server (NTRS)

    Macbain, J. C.; Kielb, R. E.; Leissa, A. W.

    1984-01-01

    The experimental portion of a joint government/industry/university research study on the vibrational characteristics of twisted cantilevered plates is presented. The overall purpose of the research study was to assess the capabilities and limitations of existing analytical methods in predicting the vibratory characteristics of twisted plates. Thirty cantilevered plates were precision machined at the Air Force's Aero Propulsion Laboratory. These plates, having five different degrees of twist, two thicknesses, and three aspect ratios representative of turbine engine blade geometries, were tested for their vibration mode shapes and frequencies. The resulting nondimensional frequencies and selected mode shapes are presented as a function of plate tip twist. The trends of the natural frequencies as a function of the governing geometric parameters are discussed. The effect of support compliance on the plate natural frequency and its impact on numerically modeling twisted plates is also presented.

  11. Musical Plates: A Study of Plate Tectonics

    NSDL National Science Digital Library

    2007-01-01

    In this project, students use Real-Time earthquake and volcano data from the Internet to explore the relationship between earthquakes, plate tectonics, and volcanoes. There is a teachers guide that explains how to use real time data, and in the same section, there is a section for curriculum standards, Supplement and enrichment activities, and assessment suggestions. Included on this webpage are four core activities, and three enrichment activities, including an activity where the student writes a letter to the president. There is also a link to reference materials that might also interest you and your students.

  12. Defects Evaluation in Lamb Wave Testing of Thin Plates

    Microsoft Academic Search

    K. Edalati; A. Kermani; B. Naderi; B. Panahi

    2005-01-01

    In the present study, dispersion and displacement c urves of ultrasonic lamb wave, propagated in Alumin um thin plates, were drawn. Two ultrasonic lamb wave techniques, pulse-echo (a1 mode as emitter) and emission (s1 mode as emitter), were used for interpretation of notch defects with depths of 10%, 30% and 60% of plate th ickness. Thickness of plate was 2

  13. Finite element formulation of orthotropic piezoceramic patch actuator laminated plates

    Microsoft Academic Search

    Ziya Koray Kusculuoglu; Thomas J. Royston

    2004-01-01

    Constitutive and finite element models of a piezoceramic laminated plate are derived using shear deformation (Mindlin plate) theory for each layer, where constraints are added to ensure the elastic deformation continuity at the interface. The major difference of this study compared to previous studies is that the finite element formulation is applicable to both thin and thick laminated plates with

  14. A set of hierarchical finite elements for quartz plate resonators

    Microsoft Academic Search

    Y.-K. Yong; J. Wang; T. Imai; S. Kanna; E. Momosaki

    1996-01-01

    Formulation of a finite strip element for high frequency quartz resonator plate vibrations is presented. The finite strip formulation is equivalent to the nth order Mindlin plate theory depending on the order of the strip in the thickness direction. Consequently the finite strip element could be used to model any high frequency resonator plate vibrations by choosing the appropriate nth

  15. License plate recognition based on support vector machine

    Microsoft Academic Search

    S. N. H. S. Abdullah; K. Omar; S. Sahran; M. Khalid

    2009-01-01

    This different types of license plates being used, the requirement of an automatic license plate recognition system is different for each country. In this paper, an automatic license plate detection system is proposed for Malaysian vehicles with standard license plates based on image processing and clustering. After applying image enhancement, the image is segmented using clustering and run length smoothing

  16. Birefringence of Muscovite Mica Plate Temperature Effect in the Ultraviolet and Visible Spectrum

    E-print Network

    Zhang, Xu; Qi, Limei; Zhang, Xia; Hao, Dianzhong

    2014-01-01

    We developed a method to measure the phase retardation and birefringence of muscovite mica plate in the temperature range of 223K to 358K within the spectrum of 300 to 700 nm. The phase retardation data is gained through the standard transmission ellipsometry using spectroscopic ellipsometer. With the phase retardation and thickness of the mica plate we can calculate its birefringence dispersion. Our results give abundant phase retardation and birefringence data of muscovite mica in the ultraviolet and visible spectrum from 223K to 358K. From the experimental data, the phase retardation and birefringence will drop down at the fixed wavelength when the temperature rises. The accuracy of the birefringence of mica plate is better than 3.5e-5.

  17. Impact on multilayered composite plates

    NASA Technical Reports Server (NTRS)

    Kim, B. S.; Moon, F. C.

    1977-01-01

    Stress wave propagation in a multilayer composite plate due to impact was examined by means of the anisotropic elasticity theory. The plate was modelled as a number of identical anisotropic layers and the approximate plate theory of Mindlin was then applied to each layer to obtain a set of difference-differential equations of motion. Dispersion relations for harmonic waves and correction factors were found. The governing equations were reduced to difference equations via integral transforms. With given impact boundary conditions these equations were solved for an arbitrary number of layers in the plate and the transient propagation of waves was calculated by means of a Fast Fourier Transform algorithm. The multilayered plate problem was extended to examine the effect of damping layers present between two elastic layers. A reduction of the interlaminar normal stress was significant when the thickness of damping layer was increased but the effect was mostly due to the softness of the damping layer. Finally, the problem of a composite plate with a crack on the interlaminar boundary was formulated.

  18. Tectonic Plates and Plate Boundaries

    NSDL National Science Digital Library

    Continents were once thought to be static, locked tight in their positions in Earth's crust. Similarities between distant coastlines, such as those on opposite sides of the Atlantic, were thought to be the work of a scientist's overactive imagination, or, if real, the result of erosion on a massive scale. This interactive feature shows 11 tectonic plates and their names, the continents that occupy them, and the types of boundaries between them.

  19. Bondability of gold wire to gold-plated electrodes

    NASA Astrophysics Data System (ADS)

    Haji, Hiroshi; Morita, Toshiaki; Arita, Kiyoshi; Nakashima, Hideharu; Yoshinaga, Hideo

    1993-10-01

    In order to clarify the dependence of wire-bondability on the thickness of plated gold film electrode and the plating method, samples with different film thicknesses were prepared by means of substitution plating, deoxidation plating, and electroplating. After the heat-treatment usually used for the integrated circuit (IC) assembling process, the samples were analyzed by means of Auger electron spectroscopy (AES) and then wire-bonded. Thin films were cut out by a microtome from the wire-bonded samples and observed by transmission electron microscopy (TEM). The effect of heat-treatment, plating method, and film thickness on the bond strength were investigated by using a shear test for the samples with films plated by the three different methods. The results obtained are as follows. (1) Without heat-treatment the bond strength did not depend on either the film thickness or plating method. (2) The nickel (from the substrate) concentration at the film surface increased with increasing heating period, and as a result the bond shear strength decreased. (3) The strength of samples wire-bonded after heat-treatment recovered when a surface layer of the gold film was removed before wire-bonding. The effect of film thickness and plating method on the wire-bondability to gold plated electrodes is further discussed.

  20. Learning Assessment #1 - Plate Tectonics

    NSDL National Science Digital Library

    Michelle Speta

    In Part 1 of this activity, students are provided with a blank topographic profile and an associated tectonic plate boundary map. Students are asked to draw a schematic cross-section on the profile down to the asthenosphere including tectonic plates (with relative thicknesses of crust etc. appropriately illustrated), arrows indicating directions of plate movement, tectonic features (mid-ocean ridges, trenches and volcanic arcs) and symbols indicating where melting is occurring at depth. In Part 2, students are asked to provide geological and geophysical lines of evidence to support their placement of convergent and divergent boundaries, respectively. A bonus question asks students to predict what would happen if spreading along the Atlantic mid-ocean ridge were to stop. Students are referred to appropriate sections of the textbook to guide them in completing all the parts of this activity. Students are also provided with a checklist of required elements for both parts of the assignment.

  1. Thermoelastic Buckling Analysis of Functionally Graded Circular Plates Integrated with Piezoelectric Layers

    Microsoft Academic Search

    A. R. Khorshidvand; M. Jabbari; M. R. Eslami

    2012-01-01

    Thermal buckling of circular plates made of functionally graded materials with surface-bounded piezoelectric layers are studied. The material properties of the FG plates are assumed to vary continuously through the plate thickness by distribution of power law of the volume fraction of the constituent materials. The general thermoelastic nonlinear equilibrium and linear stability equations for the piezoelectric FG plate are

  2. Automatic current control of magnet cranes for steel plate yard automation

    Microsoft Academic Search

    Sang Y. Park; Jin S. Lee; Joon Y. Choi; B. H. Park

    1998-01-01

    This paper presents an automatic current-control method for magnet cranes for thick steel plate yard automation. In moving the steel plates from stack to stack or from stack to shipping truck, it is difficult to lift the correct number of steel plates because the dimensions of the stacked steel plates are in general different, and their other parameters are not

  3. 30 CFR 56.12032 - Inspection and cover plates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity § 56.12032 Inspection and cover plates. Inspection and cover plates on electrical equipment and junction boxes...

  4. 30 CFR 57.12032 - Inspection and cover plates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Electricity Surface and Underground § 57.12032 Inspection and cover plates. Inspection and cover plates on electrical...

  5. 30 CFR 56.12032 - Inspection and cover plates.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity § 56.12032 Inspection and cover plates. Inspection and cover plates on electrical equipment and junction boxes...

  6. 46 CFR 64.53 - Information plate for MPTs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...TANKS AND CARGO HANDLING SYSTEMS Standards for an MPT § 64.53 Information plate for MPTs. (a) A corrosion-resistant metal plate containing the information in paragraph (b) of this section must be permanently attached to each...

  7. 46 CFR 64.53 - Information plate for MPTs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...TANKS AND CARGO HANDLING SYSTEMS Standards for an MPT § 64.53 Information plate for MPTs. (a) A corrosion-resistant metal plate containing the information in paragraph (b) of this section must be permanently attached to each...

  8. 46 CFR 64.53 - Information plate for MPTs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...TANKS AND CARGO HANDLING SYSTEMS Standards for an MPT § 64.53 Information plate for MPTs. (a) A corrosion-resistant metal plate containing the information in paragraph (b) of this section must be permanently attached to each...

  9. 46 CFR 64.53 - Information plate for MPTs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...TANKS AND CARGO HANDLING SYSTEMS Standards for an MPT § 64.53 Information plate for MPTs. (a) A corrosion-resistant metal plate containing the information in paragraph (b) of this section must be permanently attached to each...

  10. 46 CFR 64.53 - Information plate for MPTs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...TANKS AND CARGO HANDLING SYSTEMS Standards for an MPT § 64.53 Information plate for MPTs. (a) A corrosion-resistant metal plate containing the information in paragraph (b) of this section must be permanently attached to each...

  11. Stop motion microphotography of laser driven plates

    SciTech Connect

    Frank, A.M. [Lawrence Livermore National Lab., CA (United States); Trott, W.M. [Sandia National Labs., Albuquerque, NM (United States)

    1994-09-01

    Laser driven plates have been used for several years for high velocity shock wave and impact studies. Recent questions about the integrity and ablation rates of these plates coupled with an improved capability for microscopic stop motion photography led to this study. For these experiments, the plates were aluminum, coated on the ends of optical fibers. A high power laser pulse in the fiber ionizes the aluminum at the fiber/coating interface. The plasma thus created accelerates the remaining aluminum to high velocities, several kilometers per second. We defined {open_quotes}thick{close_quotes} or {open_quotes}thin{close_quotes} coatings as those where a flying plate (flyer) was launched vs. the material being completely ionized. Here we were specifically interested in the thick/thin boundary to develop data for the numerical models attempting to predict flyer behavior.

  12. Quaternions as astrometric plate constants

    NASA Technical Reports Server (NTRS)

    Jefferys, William H.

    1987-01-01

    A new method for solving problems in relative astrometry is proposed. In it, the relationship between the measured quantities and the components of the position vector of a star is modeled using quaternions, in effect replacing the plate constants of a standard four-plate-constant solution with the four components of a quaternion. The method allows a direct solution for the position vectors of the stars, and hence for the equatorial coordinates. Distortions, magnitude, and color effects are readily incorporated into the formalism, and the method is directly applicable to overlapping-plate problems. The advantages of the method include the simplicity of the resulting equations, their freedom from singularities, and the fact that trigonometric functions and tangential point transformations are not needed to model the plate material. A global solution over the entire sky is possible.

  13. A finite element parametric study of clavicle fixation plates.

    PubMed

    Pendergast, Megan; Rusovici, Razvan

    2015-06-01

    A finite element simulation on a fracture fixated clavicle was performed to study the effects of different fracture fixation parameters on the callus region. Specifically, parameters such as plate material, thickness, plate/bone gap, screw length, and locking vs. non-locking screws were explored. Plate thickness and locking vs. non-locking screws were found to be influential to construct stiffness where plate/bone gap and number of screws were not as sensitive. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25641811

  14. Tectonic Plates and Plate Boundaries (WMS)

    NSDL National Science Digital Library

    Eric Sokolowsky

    2004-06-14

    The earths crust is constantly in motion. Sections of the crust, called plates, push against each other due to forces from the molten interior of the earth. The areas where these plates collide often have increased volcanic and earthquake activity. These images show the locations of the plates and their boundaries in the earths crust. Convergent boundaries are areas where two plates are pushing against each other and one plate may be subducting under another. Divergent boundaries have two plates pulling away from each other and indicate regions where new land could be created. Transform boundaries are places where two plates are sliding against each other in opposite directions, and diffuse boundaries are places where two plates have the same relative motion. Numerous small microplates have been omitted from the plate image. These images have been derived from images made available by the United States Geological Surveys Earthquake Hazards Program.

  15. The Biggest Plates on Earth: Plate Tectonics

    NSDL National Science Digital Library

    In this lesson, students investigate the movement of Earth's tectonic plates, the results of these movements, and how magnetic anomalies present at spreading centers document the motion of the crust. As a result of this activity, students will be able to describe the motion of tectonic plates, differentiate between three types of plate boundaries, infer what type of boundary exists between two tectonic plates, and understand how magnetic anomalies provide a record of geologic history and crustal motion around spreading centers. As an example, they will also describe plate boundaries and tectonic activity in the vicinity of the Juan de Fuca plate adjacent to the Pacific Northwest coast of North America.

  16. Interferometer for measurement of absolute refractive index and thickness

    Microsoft Academic Search

    Serguei A. Alexandrov; I. V. Chernyh

    1993-01-01

    The interferometer model for measurement of the absolute refractive index of the optical media with the accuracy of 0.00001 has been developed, manufactured and researched. The sample for test to be manufactured as the flat parallel plate. The interferometer gives possibility to defined sample geometrical thickness with accuracy 0.0002 mm simultaneously with index measurement. The range of index and thickness

  17. Computing relative plate velocities: a primer

    SciTech Connect

    Bevis, M.

    1987-08-01

    Standard models of present-day plate motions are framed in terms of rates and poles of rotation, in accordance with the well-known theorem due to Euler. This article shows how computation of relative plate velocities from such models can be viewed as a simple problem in spherical trigonometry. A FORTRAN subroutine is provided to perform the necessary computations.

  18. Plate Tectonics: Diverging, Converging, and Transform Boundaries

    NSDL National Science Digital Library

    In this lesson, students will learn to distinguish the different layers of the Earth, observe the effects of plate movements, and explore the reasons for earthquakes and volcanoes. They will label and measure the thicknesses of each layer of the Earth (lithosphere, asthenosphere, etc.) and record their results, construct models from sand and clay to illustrate what happens at the three types of plate boundaries (transform, diverging, and converging), and investigate convergent plate boundaries to see which scenarios may create earthquakes and/or volcanoes.

  19. A THUMBNAIL HISTORY OF HETEROTROPHIC PLATE COUNT (HPC) METHODOLOGY IN THE UNITED STATES

    EPA Science Inventory

    Over the past 100 years, the method of determining the number of bacteria in water, foods or other materials has been termed variously as: bacterial plate count, total plate count, total viable plate count, aerobic plate count, standard plate cound and more recently, heterotrophi...

  20. Accuracy of the TRIA3 thick shell element

    NASA Technical Reports Server (NTRS)

    Case, William R.; Concha, Marco; Mcginnis, Mark

    1992-01-01

    The accuracy of the new TRIA3 thick shell element is assessed via comparison with a theoretical solution for thick homogeneous and honeycomb flat simply supported plates under the action of a uniform pressure load. The theoretical thick plate solution is based on the theory developed by Reissner and includes the effects of transverse shear flexibility which are not included in the thin plate solutions based on Kirchoff plate theory. In addition, the TRIA3 is assessed using a set of finite element test problems developed by the MacNeal-Schwendler Corp. (MSC). Comparison of the COSMIC TRIA3 element as well as those from MSC and Universal Analytics Inc. (UAI) for these problems is presented. The current COSMIC TRIA3 element is shown to have excellent comparison with both the theoretical solutions and also those from the two commercial versions of NASTRAN with which it is compared.

  1. Accuracy of the QUAD4 thick shell element

    NASA Technical Reports Server (NTRS)

    Case, William R.; Bowles, Tiffany D.; Croft, Alicia K.; Mcginnis, Mark A.

    1990-01-01

    The accuracy of the relatively new QUAD4 thick shell element is assessed via comparison with a theoretical solution for thick homogeneous and honeycomb flat simply supported plates under the action of a uniform pressure load. The theoretical thick plate solution is based on the theory developed by Reissner and includes the effects of transverse shear flexibility which are not included in the thin plate solutions based on Kirchoff plate theory. In addition, the QUAD4 is assessed using a set of finite element test problems developed by the MacNeal-Schwendler Corp. (MSC). Comparison of the COSMIC QUAD4 element as well as those from MSC and Universal Analytics, Inc. (UAI) for these test problems is presented. The current COSMIC QUAD4 element is shown to have excellent comparison with both the theoretical solutions and also those from the two commercial versions of NASTRAN that it was compared to.

  2. Torsion and transverse bending of cantilever plates

    NASA Technical Reports Server (NTRS)

    Reissner, Eric; Stein, Manuel

    1951-01-01

    The problem of combined bending and torsion of cantilever plates of variable thickness, such as might be considered for solid thin high-speed airplane or missile wings, is considered in this paper. The deflections of the plate are assumed to vary linearly across the chord; minimization of the potential energy by means of the calculus of variations then leads to two ordinary linear differential equations for the bending deflections and the twist of the plate. Because the cantilever is analyzed as a plate rather than as a beam, the effect of constraint against axial warping in torsion is inherently included. The application of this method to specific problems involving static deflection, vibration, and buckling of cantilever plates is presented. In the static-deflection problems, taper and sweep are considered.

  3. Plate Tectonics: Consequences of Plate Interactions

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2006-11-01

    This Science Object is the fourth of five Science Objects in the Plate Tectonic SciPack. It identifies the events that may occur and landscapes that form as a result of different plate interactions. The areas along plate margins are active. Plates pushing against one another can cause earthquakes, volcanoes, mountain formation, and very deep ocean trenches. Plates pulling apart from one another can cause smaller earthquakes, magma rising to the surface, volcanoes, and oceanic valleys and mountains from sea-floor spreading. Plates sliding past one another can cause earthquakes and rock deformation. Learning Outcomes:? Explain why volcanoes and earthquakes occur along plate boundaries. ? Explain how new sea floor is created and destroyed.? Describe features that may be seen on the surface as a result of plate interactions.

  4. Caribbean plate tectonics

    NSDL National Science Digital Library

    Sting

    This illustration available at Wikimedia Commons shows the plate tectonic setting in the Caribbean. Plate boundaries are color-coded by margin type and plate motions are noted with direction and magnitude in mm/yr.

  5. 7 CFR 51.2091 - Thickness.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...States Standards for Grades of Almonds in the Shell Definitions § 51.2091 Thickness...between the two semi-flat surfaces of the shell measured at right angles to a plane extending between the seams of the...

  6. 7 CFR 51.2091 - Thickness.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...States Standards for Grades of Almonds in the Shell Definitions § 51.2091 Thickness...between the two semi-flat surfaces of the shell measured at right angles to a plane extending between the seams of the...

  7. Novel 3D ultrasound image-based biomarkers based on a feature selection from a 2D standardized vessel wall thickness map: a tool for sensitive assessment of therapies for carotid atherosclerosis

    NASA Astrophysics Data System (ADS)

    Chiu, Bernard; Li, Bing; Chow, Tommy W. S.

    2013-09-01

    With the advent of new therapies and management strategies for carotid atherosclerosis, there is a parallel need for measurement tools or biomarkers to evaluate the efficacy of these new strategies. 3D ultrasound has been shown to provide reproducible measurements of plaque area/volume and vessel wall volume. However, since carotid atherosclerosis is a focal disease that predominantly occurs at bifurcations, biomarkers based on local plaque change may be more sensitive than global volumetric measurements in demonstrating efficacy of new therapies. The ultimate goal of this paper is to develop a biomarker that is based on the local distribution of vessel-wall-plus-plaque thickness change (VWT-Change) that has occurred during the course of a clinical study. To allow comparison between different treatment groups, the VWT-Change distribution of each subject must first be mapped to a standardized domain. In this study, we developed a technique to map the 3D VWT-Change distribution to a 2D standardized template. We then applied a feature selection technique to identify regions on the 2D standardized map on which subjects in different treatment groups exhibit greater difference in VWT-Change. The proposed algorithm was applied to analyse the VWT-Change of 20 subjects in a placebo-controlled study of the effect of atorvastatin (Lipitor). The average VWT-Change for each subject was computed (i) over all points in the 2D map and (ii) over feature points only. For the average computed over all points, 97 subjects per group would be required to detect an effect size of 25% that of atorvastatin in a six-month study. The sample size is reduced to 25 subjects if the average were computed over feature points only. The introduction of this sensitive quantification technique for carotid atherosclerosis progression/regression would allow many proof-of-principle studies to be performed before a more costly and longer study involving a larger population is held to confirm the treatment efficacy.

  8. Dual passband dichroic plate for X-band

    NASA Technical Reports Server (NTRS)

    Otoshi, T. Y.; Franco, M. M.

    1992-01-01

    A need arose in the NASA Deep Space Network, a worldwide tracking system, for a dichroic plate that would be transparent at two desired frequency bands in the X-band region and be totally reflective at S-band. The dual-passband dichroic plate that was developed to meet the technical requirements is a thick metallic plate having an array of periodic round holes filled with Teflon plugs. Test results on an experimental prototype plate indicate that it is technically possible to design a dielectrically filled dichroic plate that meets all of these technical requirements.

  9. 372 JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 11, NO. 4, AUGUST 2002 Deformation and Structural Stability of Layered Plate

    E-print Network

    Zhang, Katherine Yanhang

    and Structural Stability of Layered Plate Microstructures Subjected to Thermal Loading Martin L. Dunn, Yanhang­polysilicon MEMS plate microstructures fabricated by the MUMPS surface micromachining process and subjected shapes of a series of square and circular gold (0.5 m thick)/polysilicon (1.5 m thick) plate

  10. Risk factors associated with bulk tank standard plate count, bulk tank coliform count, and the presence of Staphylococcus aureus on organic and conventional dairy farms in the United States.

    PubMed

    Cicconi-Hogan, K M; Gamroth, M; Richert, R; Ruegg, P L; Stiglbauer, K E; Schukken, Y H

    2013-12-01

    The purpose of this study was to assess the association of bulk tank milk standard plate counts, bulk tank coliform counts (CC), and the presence of Staphylococcus aureus in bulk tank milk with various management and farm characteristics on organic and conventional dairy farms throughout New York, Wisconsin, and Oregon. Data from size-matched organic farms (n=192), conventional nongrazing farms (n=64), and conventional grazing farms (n=36) were collected at a single visit for each farm. Of the 292 farms visited, 290 bulk tank milk samples were collected. Statistical models were created using data from all herds in the study, as well as exclusively for the organic subset of herds. Because of incomplete data, 267 of 290 herds were analyzed for total herd modeling, and 173 of 190 organic herds were analyzed for the organic herd modeling. Overall, more bulk tanks from organic farms had Staph. aureus cultured from them (62% of organic herds, 42% conventional nongrazing herds, and 43% of conventional grazing herds), whereas fewer organic herds had a high CC, defined as ?50 cfu/mL, than conventional farms in the study. A high standard plate count (×1,000 cfu/mL) was associated with decreased body condition score of adult cows and decreased milk production in both models. Several variables were significant only in the model created using all herds or only in organic herds. The presence of Staph. aureus in the bulk tank milk was associated with fewer people treating mastitis, increased age of housing, and a higher percentage of cows with 3 or fewer teats in both the organic and total herd models. The Staph. aureus total herd model also showed a relationship with fewer first-lactation animals, higher hock scores, and less use of automatic takeoffs at milking. High bulk tank CC was related to feeding a total mixed ration and using natural service in nonlactating heifers in both models. Overall, attentive management and use of outside resources were useful with regard to CC on organic farms. In all models except the organic CC model, we observed an association with the average reported somatic cell count from 3 mo before the herd visit, indicating that many of the regularly tested milk quality parameters are interconnected. In conclusion, we found that conventional and organic farms are similar in regard to overall herd management, but each grazing system faces unique challenges when managing milk quality. PMID:24140332

  11. Inevitability of Plate Tectonics on Super-Earths

    E-print Network

    Diana Valencia; Richard J. O'Connell; Dimitar D. Sasselov

    2007-10-03

    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.

  12. Inevitability of Plate Tectonics on Super-Earths

    E-print Network

    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.

  13. Toward the standard population synthesis model of the X-ray background: Evolution of X-ray luminosity and absorption functions of active galactic nuclei including Compton-thick populations

    SciTech Connect

    Ueda, Yoshihiro [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Akiyama, Masayuki [Astronomical Institute, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Hasinger, Günther [Institute for Astronomy, 2680 Woodlawn Drive Honolulu, HI 96822-1839 (United States); Miyaji, Takamitsu [Instituto de Astronomía, Universidad Nacional Autónoma de México, Ensenada, Baja California (Mexico); Watson, Michael G. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

    2014-05-10

    We present the most up to date X-ray luminosity function (XLF) and absorption function of active galactic nuclei (AGNs) over the redshift range from 0 to 5, utilizing the largest, highly complete sample ever available obtained from surveys performed with Swift/BAT, MAXI, ASCA, XMM-Newton, Chandra, and ROSAT. The combined sample, including that of the Subaru/XMM-Newton Deep Survey, consists of 4039 detections in the soft (0.5-2 keV) and/or hard (>2 keV) band. We utilize a maximum likelihood method to reproduce the count rate versus redshift distribution for each survey, by taking into account the evolution of the absorbed fraction, the contribution from Compton-thick (CTK) AGNs, and broadband spectra of AGNs, including reflection components from tori based on the luminosity- and redshift-dependent unified scheme. We find that the shape of the XLF at z ? 1-3 is significantly different from that in the local universe, for which the luminosity-dependent density evolution model gives much better description than the luminosity and density evolution model. These results establish the standard population synthesis model of the X-ray background (XRB), which well reproduces the source counts, the observed fractions of CTK AGNs, and the spectrum of the hard XRB. The number ratio of CTK AGNs to the absorbed Compton-thin (CTN) AGNs is constrained to be ?0.5-1.6 to produce the 20-50 keV XRB intensity within present uncertainties, by assuming that they follow the same evolution as CTN AGNs. The growth history of supermassive black holes is discussed based on the new AGN bolometric luminosity function.

  14. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...representing the efficiency of welded joints, except that for seamless...representing the efficiency of welded joints, except that for seamless...in inches; r = inside knuckle radius, in inches; S...representing the efficiency of welded joints, except that for...

  15. Vibration of circular plates, of several thicknesses, with three supports

    E-print Network

    Ballentine, John Richard

    1951-01-01

    of a vacuum tube voltmet, er, I 2 3 4 5 6 7 8 9 IO II l2 r3 lg I5II l7 IP l9 202I ZZ23242$262728 0 Q FiU ~ 2 s'ochello Dgt Gg t. ":l PicLi. n Po~a'tc U, o' to Dot-bit;!1~ Dicgtu. coro&:t Curvo-, 13 . :11ctcb o . oo. lello '"a. I. ". Giga'~o'I ~'~c...

  16. Multilayer plated wire shows promise as memory device

    NASA Technical Reports Server (NTRS)

    Kadish, D.

    1968-01-01

    Multilayer plated wire memory system surpasses planar thin film memories because of its high speed, simplicity, and high output. The device consists of 5 mil Be-Cu wire plated with Ni-Fe alloy about 1 micron thick crossed orthogonally by word lines.

  17. REFINED THEORY FOR THERMOELASTIC STABILITY OF FUNCTIONALLY GRADED CIRCULAR PLATES

    Microsoft Academic Search

    M. M. Najafizadeh; B. Hedayati

    2004-01-01

    Axisymmetric thermal and mechanical buckling of functionally graded circular plates is considered. Equilibrium and stability equations under thermal and mechanical loads are derived based on first-order shear deformation plate theory. Assuming that the material properties vary as a power form of the thickness coordinate variable z and using the variational method, the system of fundamental ordinary differential equations is established.

  18. Fatigue behaviour of punched structural plates

    Microsoft Academic Search

    L Sánchez; F Gutiérrez-Solana; D Pesquera

    2004-01-01

    In the framework of a research project on the performance criteria of cold formed structural steels [1], a study of fatigue behaviour is being carried out by means of the determination of the Wöhler curves (S–N) in 15 mm thick plates with different steel qualities and 15 mm diameter holes, made by punching and drilling. The different behaviour obtained has

  19. Taub, Rindler, and the static plate

    Microsoft Academic Search

    A F F Teixeira

    2005-01-01

    An infinite 3D plate of homogeneous incompressible fluid is considered, with finite thickness, together with a 2D infinite homogeneous mass in its centre. Einstein equations are exactly solved, in the interior of the 3D mass. The solution is joined to the exterior vacuum metric of Taub. Every value for the 2D mass, positive or negative, allows a perfect junction. Also

  20. Mechanical and thermal buckling analysis of functionally graded plates

    Microsoft Academic Search

    X. Zhao; Y. Y. Lee; K. M. Liew

    2009-01-01

    The mechanical and thermal buckling analysis of functionally graded ceramic–metal plates is presented in this study. The first-order shear deformation plate theory, in conjunction with the element-free kp-Ritz method, is employed in the current formulation. It is assumed that the material property of each plate varies exponentially through the thickness. The displacement field is approximated in terms of a set

  1. A sensitive and simple plaque formation method for the Stx2 phage of Escherichia coli O157:H7, which does not form plaques in the standard plating procedure.

    PubMed

    Islam, Md Rakibul; Ogura, Yoshitoshi; Asadulghani, Md; Ooka, Tadasuke; Murase, Kazunori; Gotoh, Yasuhiro; Hayashi, Tetsuya

    2012-05-01

    Bacteriophages are fascinating genetic elements that play key roles in the evolution and diversification of bacterial genomes. Shiga toxin (Stx)-transducing phages are important genetic elements that disseminate the stx genes among enterohemorrhagic Escherichia coli (EHEC). They are generally regarded as lambda-like phages, but their biological and genetic properties have not been fully elucidated. This is partly due to a serious obstacle in obtaining visible plaques. Here, we describe a modified double agar overlay method that allows us to easily detect and accurately enumerate plaques of Sp5, the Stx2 phage of the EHEC O157 Sakai strain, which otherwise does not produce plaques in the standard plating procedure. In the modified method, the top agar was supplemented with mitomycin C (MMC) and Ca(2+) (or Mg(2+)). MMC appears to prevent the lysogenization of Sp5 and/or compel Sp5 to follow the lytic cycle by inducing the SOS response in the host cells. The divalent cations significantly improve phage adsorption to the host cells and thus yield a synergistic effect in combination with MMC. We further applied this method to a receptor analysis of Sp5 and obtained findings that suggest that the YaeT (BamA) protein serves as the receptor of Sp5. This method would be a very useful tool in studies of Stx2 phages and studies of other phages from various bacteria, in which researchers often encounter problems with plaque formation. PMID:22186359

  2. Copper Map Plate Detail

    USGS Multimedia Gallery

    A portion of the engraving on the plate used to print points, lines, and text in black ink. Engravings on the plate are left-to-right reversed. This plate was cleaned and treated to improve the visibility of the engraving. The plate was used to print the Washington [D.C.] and vicinity, 1:31,680-sca...

  3. Sputtering and ion plating

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The proceedings of a conference on sputtering and ion plating are presented. Subjects discussed are: (1) concepts and applications of ion plating, (2) sputtering for deposition of solid film lubricants, (3) commercial ion plating equipment, (4) industrial potential for ion plating and sputtering, and (5) fundamentals of RF and DC sputtering.

  4. Plate Tectonics Animation

    NSDL National Science Digital Library

    2002-01-01

    Plate tectonics describes the behavior of Earth's outer shell, with pieces (plates) bumping and grinding and jostling each other about. Explore these maps and animations to get a jump start on understanding plate tectonic processes, history, and how motion of the plates affects our planet today.

  5. Local plate/rod descriptors of 3D trabecular bone micro-CT images from medial axis topologic analysis

    SciTech Connect

    Peyrin, Francoise; Attali, Dominique; Chappard, Christine; Benhamou, Claude Laurent [CREATIS, UMR CNRS 5220, 69621 Villeurbanne (France); Inserm, U 630, 69621 Villeurbanne (France); Insa de Lyon, 69621 Villeurbanne (France); Universite Lyon I, 69621 Villeurbanne (France); Universite de Lyon, 69621 Villeurbanne (France) and ESRF (European Synchrotron Radiation Facility), BP 220, 38043 Grenoble (France); GIPSA Laboratory, UMR CNRS 5216, 38402 Grenoble (France); Inserm, U 658, 45032 Orleans Cedex 1 (France) and B20A, UMR7052 CNRS, Universite Paris 7, 75010 Paris (France); Inserm, U 658, 45032 Orleans Cedex 1 (France)

    2010-08-15

    Purpose: Trabecular bone microarchitecture is made of a complex network of plate and rod structures evolving with age and disease. The purpose of this article is to propose a new 3D local analysis method for the quantitative assessment of parameters related to the geometry of trabecular bone microarchitecture. Methods: The method is based on the topologic classification of the medial axis of the 3D image into branches, rods, and plates. Thanks to the reversibility of the medial axis, the classification is next extended to the whole 3D image. Finally, the percentages of rods and plates as well as their mean thicknesses are calculated. The method was applied both to simulated test images and 3D micro-CT images of human trabecular bone. Results: The classification of simulated phantoms made of plates and rods shows that the maximum error in the quantitative percentages of plate and rods is less than 6% and smaller than with the structure model index (SMI). Micro-CT images of human femoral bone taken in osteoporosis and early or advanced osteoarthritis were analyzed. Despite the large physiological variability, the present method avoids the underestimation of rods observed with other local methods. The relative percentages of rods and plates were not significantly different between osteoarthritis and osteoporotic groups, whereas their absolute percentages were in relation to an increase of rod and plate thicknesses in advanced osteoarthritis with also higher relative and absolute number of nodes. Conclusions: The proposed method is model-independent, robust to surface irregularities, and enables geometrical characterization of not only skeletal structures but entire 3D images. Its application provided more accurate results than the standard SMI on simple simulated phantoms, but the discrepancy observed on the advanced osteoarthritis group raises questions that will require further investigations. The systematic use of such a local method in the characterization of trabecular bone samples could provide new insight in bone microarchitecture changes related to bone diseases or to those induced by drugs or therapy.

  6. Mapping Plate Tectonic Boundaries

    NSDL National Science Digital Library

    Michael Kerwin

    To prepare for this activity, students do background reading on Plate Tectonics from the course textbook. Students also participate in a lecture on the discovery and formulation of the unifying theory of plate tectonics, and the relationship between plate boundaries and geologic features such as volcanoes. Lastly, in lecture, students are introduced to a series of geologic hazards caused by certain plate tectonic interactions. The activity gives students practices at identifying plate boundaries and allows them to explore lesser known tectonically active regions.

  7. Accurate stress resultants equations for laminated composite deep thick shells

    SciTech Connect

    Qatu, M.S. [Franklin Univ., Columbus, OH (United States)

    1995-11-01

    This paper derives accurate equations for the normal and shear force as well as bending and twisting moment resultants for laminated composite deep, thick shells. The stress resultant equations for laminated composite thick shells are shown to be different from those of plates. This is due to the fact the stresses over the thickness of the shell have to be integrated on a trapezoidal-like shell element to obtain the stress resultants. Numerical results are obtained and showed that accurate stress resultants are needed for laminated composite deep thick shells, especially if the curvature is not spherical.

  8. Buckling and Free Vibration Analysis of Symmetric and Antisymmetric Laminated Composite Plates on an Elastic Foundation

    Microsoft Academic Search

    S. S. Akavci

    2007-01-01

    Buckling and free vibration analysis of simply supported symmetric and antisym- metric cross-ply thick composite plates on elastic foundation are examined by a new hyperbolic displacement model in this paper. In this new model, inplane displacements vary as a hyperbolic function across the plate thickness, so account for parabolic distributions of transverse shear stresses and satisfy zero shear stress conditions

  9. Finite stretching of a circular plate of neo-Hookean material.

    NASA Technical Reports Server (NTRS)

    Biricikoglu, V.

    1971-01-01

    The analytical solution presented is based on the assumption that the deformed thickness of the plate is approximately constant. The nonlinear equations governing finite axisymmetric deformations of a circular plate made of neo-Hookean material are used in the analysis. The variation of circumferential extension ratio and the variation of deformed thickness are shown in graphs.

  10. A statistical comparison of gold and palladium-nickel plating systems for various fretting parameters

    Microsoft Academic Search

    Cai-rie A. Morse; Neil R. Aukland; Harry C. Hardee

    1995-01-01

    An electrodeposited plating system of gold over an 80Pd-20Ni alloy is a promising contact material that potentially offers the advantages of thick gold plate at significantly lower cost. This paper presents the statistical and experimental evaluation of various fretting parameters on the contact resistance stability of a simulated separable connector contact interface. The parameters were: gold bath, gold thickness, amplitude

  11. Acceleration of thin flyer plates by laser plasmas

    Microsoft Academic Search

    Masatake Yoshida; Kunihiko Wakabayashi; Naoshi Kozu; Yasufumi Sasatani; Hisataka Takenaka; Kazuo A. Tanaka; Ken-Ichi Kondo

    1999-01-01

    Experimental results of laser plasma acceleration of thin Ta flyer plates are presented. The target assembly consists of three layers; aluminum, polyimide and Ta layers. Ta layer had 0.5 ~ 5 mum thickness and was physically vapor deposited on the polyimide layer of 150 mum thickness. Two laser beams, 250 J and 2 ns falat--top each, of GEKKO XII irradiated

  12. Thickness effect criterion for fatigue strength evaluation of welded steel structures

    Microsoft Academic Search

    J. Yagi; Y. Tomita; S. Machida; M. Matoba; I. Soya

    1993-01-01

    From a practical point of view, some measures to reduce the thickness effect backed by a reasonable criterion are required for fabricating structures with heavy section plates. In this study, the thickness effect was investigated by systematic experiments on welded steel joints with thicknesses ranging from 10 to 80 mm. Cruciform joints and T-joints with improved weld by overall profiling

  13. Automatic cortical thickness analysis on rodent brain

    NASA Astrophysics Data System (ADS)

    Lee, Joohwi; Ehlers, Cindy; Crews, Fulton; Niethammer, Marc; Budin, Francois; Paniagua, Beatriz; Sulik, Kathy; Johns, Josephine; Styner, Martin; Oguz, Ipek

    2011-03-01

    Localized difference in the cortex is one of the most useful morphometric traits in human and animal brain studies. There are many tools and methods already developed to automatically measure and analyze cortical thickness for the human brain. However, these tools cannot be directly applied to rodent brains due to the different scales; even adult rodent brains are 50 to 100 times smaller than humans. This paper describes an algorithm for automatically measuring the cortical thickness of mouse and rat brains. The algorithm consists of three steps: segmentation, thickness measurement, and statistical analysis among experimental groups. The segmentation step provides the neocortex separation from other brain structures and thus is a preprocessing step for the thickness measurement. In the thickness measurement step, the thickness is computed by solving a Laplacian PDE and a transport equation. The Laplacian PDE first creates streamlines as an analogy of cortical columns; the transport equation computes the length of the streamlines. The result is stored as a thickness map over the neocortex surface. For the statistical analysis, it is important to sample thickness at corresponding points. This is achieved by the particle correspondence algorithm which minimizes entropy between dynamically moving sample points called particles. Since the computational cost of the correspondence algorithm may limit the number of corresponding points, we use thin-plate spline based interpolation to increase the number of corresponding sample points. As a driving application, we measured the thickness difference to assess the effects of adolescent intermittent ethanol exposure that persist into adulthood and performed t-test between the control and exposed rat groups. We found significantly differing regions in both hemispheres.

  14. Macular Thickness and Amblyopia

    PubMed Central

    Rajavi, Zhale; Moghadasifar, Hossein; Feizi, Mohadese; Haftabadi, Narges; Hadavand, Reza; Yaseri, Mehdi; Sheibani, Kourosh; Norouzi, Ghazal

    2014-01-01

    Purpose: To compare macular thickness in children with functional amblyopia and those without amblyopia using optical coherence tomography (OCT). Methods: This case-control study was conducted on 93 children aged 3–10 years including 44 cases with unilateral amblyopia and 49 subjects without amblyopia. Amblyopic eyes were considered as the case group and their fellow eyes as internal controls; eyes of non-amblyopic children served as the external control. Macular thickness of all eyes were measured by optical coherence tomography in the center (foveola), 1 mm ring (fovea), and 3 and 6 mm rings and compared. Results: Although macular thickness was generally not different between the study groups, there was a significant difference in central macular thickness between eyes with moderate to severe amblyopia and the external controls (P = 0.037). Foveal thickness difference exceeding 10 microns between fellow eyes was detected in a larger number of amblyopic children as compared to non-amblyopic controls (P = 0.002). Mean foveal thickness was greater in boys (P = 0.037) but there was no significant difference in foveal thickness among various types of refractive errors. Conclusion: Although there was no significant relationship between macular thickness and amblyopia, foveolar thickness in eyes with moderate to severe amblyopia was significantly greater than the external controls. Further studies with more cases of moderate to severe amblyopia are recommended. PMID:25709774

  15. Redesign of plates by large admissible perturbations

    NASA Astrophysics Data System (ADS)

    Bernitsas, Michael M.; Rim, Chae Whan

    1994-05-01

    The problem of structural redesign of plates for static deflection and modal dynamics objectives is formulated and solved by the method of large admissible perturbations. The perturbation approach to redesign is first used to develop response equations for the objective plate design based on its specifications and the baseline plate design. The equations of the objective state are strongly nonlinear implicit expressions of the variable plate thickness. A large admissible perturbations algorithm is developed to solve the plate redesign problem and define the optimal objective state. The latter is reached incrementally with a prediction-correction scheme without repeated finite element analyses. Systematic numerical applications in redesign of a cantilever plate of 216 degrees of freedom are used to investigate the effects of number of extracted modes and redesign variables. It is shown that the large admissible perturbations theory can be used efficiently to redesign plates for multiple specifications that require changes to the baseline design and its response of the order of 100%.

  16. Scaling of energy absorbing composite plates

    NASA Technical Reports Server (NTRS)

    Jackson, Karen; Morton, John; Traffanstedt, Catherine; Boitnott, Richard

    1992-01-01

    The energy absorption response and crushing characteristics of geometrically scaled graphite-Kevlar epoxy composite plates were investigated. Three different trigger mechanisms including chamfer, notch, and steeple geometries were incorporated into the plate specimens to initiate crushing. Sustained crushing was achieved with a simple test fixture which provided lateral support to prevent global buckling. Values of specific sustained crushing stress (SSCS) were obtained which were comparable to values reported for tube specimens from previously published data. Two sizes of hybrid plates were fabricated; a baseline or model plate, and a full-scale plate with in-plane dimensions scaled by a factor of two. The thickness dimension of the full-scale plates was increased using two different techniques; the ply-level method in which each ply orientation in the baseline laminate stacking sequence is doubled, and the sublaminate technique in which the baseline laminate stacking sequence is repeated as a group. Results indicated that the SSCS is independent of trigger mechanism geometry. However, a reduction in the SSCS of 10-25 percent was observed for the full-scale plates as compared with the baseline specimens, indicating a scaling effect in the crushing response.

  17. Scaling of energy absorbing composite plates

    NASA Technical Reports Server (NTRS)

    Jackson, Karen; Lavoie, J. Andre; Morton, John

    1994-01-01

    The energy absorption response and crushing characteristics of geometrically scaled graphite-Kevlar epoxy composite plates were investigated. Two different trigger mechanisms including notch, and steeple geometries were incorporated into the plate specimens to initiate crushing. Sustained crushing was achieved with a new test fixture which provided lateral support to prevent global buckling. Values of specific sustained crushing stress (SSCS) were obtained which were lower than values reported for tube specimens from previously published data. Two sizes of hybrid plates were fabricated; a baseline or model plate, and a full-scale plate with inplane dimensions scaled by a factor of two. The thickness dimension of the full-scale plates was increased using two different techniques: the ply-level method in which each ply orientation in the baseline laminate stacking sequence is doubled, and the sublaminate technique in which the baseline laminate stacking sequence is repeated as a group. Results indicated that the SSCS has a small dependence on trigger mechanism geometry. However, a reduction in the SSCS of 10-25% was observed for the full-scale plates as compared with the baseline specimens, indicating a scaling effect in the crushing response.

  18. Global Plate Driving Forces at 50Ma

    NASA Astrophysics Data System (ADS)

    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.

  19. A Baffle Plate For Subsurface Acoustic Module In High Ship-noise Operation

    Microsoft Academic Search

    Ham Matsumoto; Edward Noda; J. Sharkey; Frank McHale

    1991-01-01

    Development of a baffle plate useful for: shielding a subsurface acoustic module from high acoustic noise of a surface ship is described. The baffle plate was made of 12.7 cm (5”) thick steel plate, octagonal in shape with a 1 m diagonal length. The lower surface was covered with a layer of an acoustic absorption material, SAPER-DTM. A test was

  20. Crustal thickness variations in Venezuela from deep seismic observations

    NASA Astrophysics Data System (ADS)

    Schmitz, M.; Avila, J.; Bezada, M.; Vieira, E.; Yáñez, M.; Levander, A.; Zelt, C. A.; Jácome, M. I.; Magnani, M. B.; The Bolivar Active Seismic Working Group

    2008-11-01

    The Caribbean-South America plate boundary zone is a complex zone of plate interactions, forming thrust belts and foreland basins in northern Venezuela. Within the framework of the BOLIVAR and GEODINOS projects, the geodynamics of plate interactions is being investigated using interdisciplinary geological and geophysical methods. Here, we focus on the results of the land based active seismic observations done in 2004 along four deep seismic wide angle profiles, acquired perpendicular to the Caribbean-South America plate boundary in northern Venezuela between longitudes 63° W and 70° W, and ranging from about latitudes 12 °N to about 9 °N. The mostly unreversed profiles provide information on the crustal structure from the oceanic-transitional crust on the southern border of the Caribbean plate to the continental crust of the Caribbean Mountain System and their associated foreland basins, which are bordered to the south by the Guayana Shield, which corresponds to stable South America plate. The derived crustal thickness oscillates around 35 km along the coastline, corresponding to the Caribbean Mountain System, and decreases only slightly towards the Leeward Antilles. To the south, in the area of the Eastern Venezuela Basin, crustal thickness reaches 40 km, increasing towards the Guayana Shield to 45 km. Nevertheless, there are two regions of anomalous crustal thickness, proven by arrivals from the lower crust and the Moho discontinuity. In the eastern part of the Eastern Venezuela Basin, crustal thickness reaches up to 50 km, with high velocity anomalies within the lower crust, which are interpreted as reworked lower crustal and upper mantle material, associated to the plate interactions of the South American and the Caribbean plates. The second anomalous zone is a remarkable crustal thinning from 35 km to 27 km in the Falcón Basin in western Venezuela, which extends eastwards into the Bonaire Basin, as documented by PmP reflections derived from land shots, and observations of the air gun blasts on the stations of the Venezuelan seismological network.

  1. Design of laminated composite plates for maximum shear buckling loads

    SciTech Connect

    Chang, R.R.; Chu, K.H.; Kam, T.Y. [National Chiao Tung Univ., Hsin Chu (Taiwan, Province of China). Dept. of Mechanical Engineering

    1993-12-01

    The optimal lamination arrangements of laminated composite plates with maximum shear buckling loads are studied via a multi-start global optimization technique. A previously proposed shear deformable finite element is used to evaluate the positive and negative shear buckling loads of laminated composite plates in the optimal design process. Optimal lay-ups of thin as well as moderately thick composite plates with global maximum positive or negative shear buckling loads are determined utilizing the multi-start global optimal design technique. A number of examples of the optimal shear buckling design of symmetrically and antisymmetrically laminated composite plates with various material properties, length-to-thickness ratios, aspect ratios and different numbers of layer groups are given to illustrate the trends of optimal layer orientations of the plates. Since the existence of in-plane axial force is possible, the effects of axial compressive load on the optimal layer orientations for maximum shear buckling load are also investigated.

  2. Solderability and environmental testing of Sn-plated surfaces

    SciTech Connect

    Sorensen, N.R.; Hosking, F.M.

    1990-01-01

    The effect of atmospheric corrosion on the solderability of Sn plated surfaces was evaluated with 60Sn-40Pb solder. Tin thicknesses of 10, 50, and 150 {mu}in on Ni plated Cu were studied. The 10 {mu}in. plating gave the smallest solder meniscus rise. A general decrease in contact angle, or increase in wettability, was observed with increasing Sn plating. The environmental exposures retarded the wetting rate and increased the time to maximum wetting, particularly with only 10 {mu}in. of Sn. Although the solderability of the 50 and 150 {mu}in. surfaces wee not significantly affected by the test conditions, an intermediate plating thickness of 100 {mu}in. is preferred for processing flexibility. 13 refs., 7 figs., 1 tab.

  3. Comminuted quadrilateral plate fracture fixation through the iliofemoral approach.

    PubMed

    Sen, Ramesh Kumar; Tripathy, Sujit Kumar; Aggarwal, Sameer; Goyal, Tarun; Mahapatra, Santosh Kumar

    2013-02-01

    Comminuted quadrilateral plate fracture with medial displacement is a technically difficult fracture to treat. Minimal bone stock, proximity to the hip joint with limited surgical access, and difficulty in obtaining a stable fixation at this area, contribute to the surgical challenge of open reduction and internal fixation. Fixation of a medial buttress plate in an infrapectineal fashion is a well-described technique to address such fractures. However, this plate alone may be inadequate to buttress all the fragments in a grossly comminuted quadrilateral plate fracture. An additional spring plate is often placed underneath the infrapectineal plate to hold the fracture fragments. Conventionally, these spring plates are fixed to the ilium superiorly while the other end buttresses the quadrilateral plate when placed underneath the infrapectineal reconstruction plate. The standard ilioinguinal approach and modified Stoppa approach have been described for the surgical access to the quadrilateral plate. Both the approaches have some limitations in addressing quadrilateral plate fracture. The ilioinguinal approach requires extensive dissection and mobilisation of inguinal neurovascular bundle. The modified Stoppa approach does not permit visualisation of the entire anterior column and the hip joint. The authors, in this article, describe the fixation of the comminuted quadrilateral plate fracture through the iliofemoral approach combined with a medial ilioinguinal window. The technique involves fixation of a spring plate (Allis T-plate) at right angle to the infrapectineal buttress plate (90°-90° plate construct). The vertical limb of the T-plate is fixed to the iliopectineal eminence whereas the horizontal limb buttresses the quadrilateral plate Hence, this technique addresses fractures of both the iliopectineal eminence and the quadrilateral plate. Other than that, the iliofemoral approach permits direct visualisation of the entire anterior column and the hip joint without the necessity to dissect the ilioinguinal neurovascular structures. PMID:23199759

  4. The PLATES Project

    NSDL National Science Digital Library

    This is the web page for PLATES, a program of research into plate tectonic and geologic reconstructions at the University of Texas at Austin Institute for Geophysics. The page contains links to a brief overview of plate tectonics and plate reconstructions using the PLATES Project's global plate reconstruction model, in addition to movies in the format of powerpoint animations which can be downloaded for later use. Models are shown on the evolution of the earth's oceans and the movement of the earth's tectonic plates from the Late Precambrian through the present day, reconstructing (i.e. "predicting") geological environments through geologic history. Maps of the following can be accessed: late Neo-Proterozoic, Silurian, early Jurassic, early Cretaceous, Cretaceous-Tertiary Boundary, and Oligocene. Movies are available on the following subjects: global plate motion, Jurassic to present day, opening of the Indian Ocean, and tectonic evolution of the Arctic region.

  5. Understanding Plate Motions

    NSDL National Science Digital Library

    The representation shows divergent boundaries, convergent boundaries, transform boundaries, and plate boundary zones through a series of diagrams. Some of the diagrams are accompanied by a photographs. Accompanying text explains plate movement at each type of boundary.

  6. Portable Plating System

    NASA Technical Reports Server (NTRS)

    Flores, R.

    1984-01-01

    Plating system mounted on portable cart includes 30-gallon (23.5 liter) electrolyte tank, filler pump, heaters, replenishing anodes, plating rectifiers and tank rectifier to continously remove contaminants.

  7. External Resource: Plate Tectonics

    NSDL National Science Digital Library

    1900-01-01

    This Windows to the Universe interactive webpage connects students to the study and understanding of plate tectonics, the main force that shapes our planets surface. Topics: plate tectonics, lithosphere, subduction zones, faults, ridges.

  8. Plate Tectonics: Further Evidence

    NSDL National Science Digital Library

    The representation depicts the spreading of the sea floor along the mid-ocean ridges. The resource generally describes the theory of plate tectonics, including the movement of plates with regard to one another.

  9. Earth's Decelerating Tectonic Plates

    SciTech Connect

    Forte, A M; Moucha, R; Rowley, D B; Quere, S; Mitrovica, J X; Simmons, N A; Grand, S P

    2008-08-22

    Space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions are employed to determine a new global map of present-day rates of change of plate velocities. This map shows that Earth's largest plate, the Pacific, is presently decelerating along with several other plates in the Pacific and Indo-Atlantic hemispheres. These plate decelerations contribute to an overall, globally averaged slowdown in tectonic plate speeds. The map of plate decelerations provides new and unique constraints on the dynamics of time-dependent convection in Earth's mantle. We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data to show that time-dependent changes in mantle buoyancy forces can explain the deceleration of the major plates in the Pacific and Indo-Atlantic hemispheres.

  10. Laser polishing of diamond plates

    NASA Astrophysics Data System (ADS)

    Pimenov, S. M.; Kononenko, V. V.; Ralchenko, V. G.; Konov, V. I.; Gloor, S.; Lüthy, W.; Weber, H. P.; Khomich, A. V.

    Results are reported on laser polishing of 150-400-?m-thick free-standing diamond films with either a copper vapor laser (510 nm wavelength) or an ArF excimer laser (193 nm wavelength). Studies were focused on three particular goals. First, we aimed at a choice of optimum conditions for laser polishing of thick diamond films. It was shown that the laser polishing conditions and the resulting surface roughness were controlled by varying the angle of incidence of a scanning laser beam and by polishing time. Second, the laser ablation technique was applied to remove a defective layer from the ``substrate'' side of the diamond plates in order to reduce optical losses due to absorption in this layer. Third, the structure of the laser-graphitized diamond surface was studied using UV, visible, and IR optical spectroscopy techniques in the course of the ``step-by-step'' oxidative removal of the graphitic layer with increasing temperature of the oxidation in ambient air. Once the graphitic layer was removed, the optical transmission in the UV-visible-IR spectral range of the diamond films polished under optimum conditions was measured and compared with the optical transmission of the mechanically polished diamond films. It was shown that the optical quality (in the long-wave infrared region) of the laser-polished diamond plates was sufficient to reach the transmittance value very close to the theoretical limit.

  11. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, Barbara S. (Knoxville, TN); Lauf, Robert J. (Oak Ridge, TN)

    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.

  12. Education and "Thick" Epistemology

    ERIC Educational Resources Information Center

    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…

  13. Plate Tectonics: Moving Middle School Science

    NSDL National Science Digital Library

    Carolee Barber

    This resource guide from the Middle School Portal 2 project, written specifically for teachers, provides links to exemplary resources including background information, lessons, career information, and related national science education standards. This wiki page is about plate tectonics and features online resources that were hand-picked for middle school teachers. The resources are organized into three sets: background information (for teachers and students), activities (single-day and multiple-day), and animations. National Science Education Standards related to plate tectonics are also provided. Each resource set begins with a discussion of its strengths. For example, students work with models and data in the activities, many of which are discovery-oriented. Teaching tips and usage suggestions are offered in the set introductions and in the descriptions of individual resources. Together, the resources address topics such as the development of the plate tectonics theory and the types of plate boundaries and their locations.

  14. Plate Tectonic Theory

    NSDL National Science Digital Library

    John Louie

    This is the web site for a Plate Tectonics Theory class at The University of Nevada, Reno. The home page/syllabus contains links to several of the topics covered in the course. The topics with web based lecture materials are earthquake seismology, structure of the Earth, composition of the Earth, lithospheric deformation, the plate tectonics paradigm, and the driving mechanisms of plate tectonics.

  15. Paper terahertz wave plates.

    PubMed

    Scherger, Benedikt; Scheller, Maik; Vieweg, Nico; Cundiff, Steven T; Koch, Martin

    2011-12-01

    We present a low-cost terahertz wave plate based on form birefringence fabricated using ordinary paper. Measurements of the transfer function of the wave plate between polarizers closely agree with predictions based on the measured complex indices of refraction of the effective medium. For the design frequency, the dependence on wave plate angle also agrees with theory. PMID:22273881

  16. Plate Tectonic Primer

    NSDL National Science Digital Library

    Lynn Fichter

    This site gives an in-depth look at the theory of plate tectonics and how it works. The structure of the Earth is discussed, with brief rock type descriptions. The structure of the lithosphere, plate boundaries, interplate relationships, and types of plates are all covered in detail.

  17. Earthquakes and Plate Tectonics

    NSDL National Science Digital Library

    This article describes the theory of plate tectonics and its relation to earthquakes and seismic zones. Materials include an overview of plate tectonics, a description of Earth's crustal plates and their motions, and descriptions of the four types of seismic zones.

  18. Thickness-shear and thickness-twist modes in an AT-cut quartz acoustic wave filter.

    PubMed

    Zhao, Zinan; Qian, Zhenghua; Wang, Bin; Yang, Jiashi

    2015-04-01

    We studied thickness-shear and thickness-twist vibrations of a monolithic, two-pole crystal filter made from a plate of AT-cut quartz. The scalar differential equations derived by Tiersten and Smythe for electroded and unelectroded quartz plates were employed which are valid for both the fundamental and the overtone modes. Exact solutions for the free vibration resonant frequencies and modes were obtained from the equations. For a structurally symmetric filter, the modes can be separated into symmetric and antisymmetric ones. Trapped modes with vibrations mainly under the electrodes were found. The effect of the distance between the two pairs of electrodes was examined. PMID:25627930

  19. Assessment of Nuclear Fuels using Radiographic Thickness Measurement Method

    SciTech Connect

    Muhammad Abir; Fahima Islam; Hyoung Koo Lee; Daniel Wachs

    2014-11-01

    The Convert branch of the National Nuclear Security Administration (NNSA) Global Threat Reduction Initiative (GTRI) focuses on the development of high uranium density fuels for research and test reactors for nonproliferation. This fuel is aimed to convert low density high enriched uranium (HEU) based fuel to high density low enriched uranium (LEU) based fuel for high performance research reactors (HPRR). There are five U.S. reactors that fall under the HPRR category, including: the Massachusetts Institute of Technology Reactor (MITR), the National Bureau of Standards Reactor (NBSR), the Missouri University Research Reactor (UMRR), the Advanced Test Reactor (ATR), and the High Flux Isotope Reactor (HFIR). U-Mo alloy fuel phase in the form of either monolithic or dispersion foil type fuels, such as ATR Full-size In center flux trap Position (AFIP) and Reduced Enrichment for Research and Test Reactor (RERTR), are being designed for this purpose. The fabrication process1 of RERTR is susceptible to introducing a variety of fuel defects. A dependable quality control method is required during fabrication of RERTR miniplates to maintain the allowable design tolerances, therefore evaluating and analytically verifying the fabricated miniplates for maintaining quality standards as well as safety. The purpose of this work is to analyze the thickness of the fabricated RERTR-12 miniplates using non-destructive technique to meet the fuel plate specification for RERTR fuel to be used in the ATR.

  20. A backing plate for quartz crystal resonators improves the baseline stability and the baseline reproducibility

    NASA Astrophysics Data System (ADS)

    Böttcher, Andreas; Peschel, Astrid; Johannsmann, Diethelm

    2015-03-01

    We report on a simple way to hold quartz crystal resonators, which allows for removal of the crystal from a liquid cell and reinsertion into the cell without losing the reference frequency. The crystal is permanently glued to a circular backing plate with a diameter of 1?inch (25.4?mm), where the latter takes up most of the stress occurring during handling. The backing plate also provides for electrical connections. Reduced stress has three effects, which are a reduced frequency drift during an experiment, a reduced variability of frequency upon reinsertion into the cell and an increased lifetime of the crystals. The standard deviation in f/n (f the frequency, n the overtone order) upon reinsertion into a cell was between 0.4 and 1?Hz, which corresponds to an uncertainty in film thickness between 0.08 and 0.2?nm (assuming a fundamental frequency of 5?MHz and a density of the film of 1?g?cm?3). In most experimental regards, the crystal-plate assembly can be treated as if it were a 1?inch crystal. Since the cost of the backing plate is less than the cost of a crystal, it can be treated as a disposable item like the crystal itself.

  1. Fuel Cell Thermal Management Through Conductive Cooling Plates

    NASA Technical Reports Server (NTRS)

    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.

  2. LIM, CHEMIN. Low Cycle Fatigue Life Prediction of Four Bolt Extended Unstiffened End Plate Moment Connections. (Under the direction of Emmett A Sumner.)

    E-print Network

    ABSTRACT LIM, CHEMIN. Low Cycle Fatigue Life Prediction of Four Bolt Extended Unstiffened End Plate of connection. The parametric study identified the end plate thickness, the beam flange thickness, and the bolt Bolt Extended Unstiffened End Plate Moment Connections by Chemin Lim A dissertation submitted

  3. An improved plating process

    NASA Technical Reports Server (NTRS)

    Askew, John C.

    1994-01-01

    An alternative to the immersion process for the electrodeposition of chromium from aqueous solutions on the inside diameter (ID) of long tubes is described. The Vessel Plating Process eliminates the need for deep processing tanks, large volumes of solutions, and associated safety and environmental concerns. Vessel Plating allows the process to be monitored and controlled by computer thus increasing reliability, flexibility and quality. Elimination of the trivalent chromium accumulation normally associated with ID plating is intrinsic to the Vessel Plating Process. The construction and operation of a prototype Vessel Plating Facility with emphasis on materials of construction, engineered and operational safety and a unique system for rinse water recovery are described.

  4. Malachite green photosensitive plates.

    PubMed

    Solano, C

    1989-08-15

    An experimental study of the behavior of malachite green sensitized plates was carried out. The transmittance variation of the irradiated plates was taken as a parameter. It has been observed that photoreduction in the malachite green plates is present only when ammonium dichromate is added to the plates. The introduction of external electron donors does not improve the photochemical reaction. It has been determined that malachite green molecules form a weak complex with the dichromate molecules and this complex can only be destroyed photochemically. This effect can explain the limited response of the malachite green dichromated plates. PMID:20555732

  5. Discovering Plate Boundaries

    NSDL National Science Digital Library

    Alison Henning

    Students are initially assigned to one of four maps of the world: Seismology, Volcanology, Geochronology or Topography. They are also given a map of the world's plate boundaries and are asked to classify the boundaries based upon the data from their assigned map. Students are then assigned to a tectonic plate, such that each plate group contains at least one "expert" on each map. As a group, they must classify their plate's boundaries using data from all four maps. Recent volcanic and seismic events are discussed in the plate tectonic context. Has minimal/no quantitative component Uses geophysics to solve problems in other fields

  6. Multicolor printing plate joining

    NASA Technical Reports Server (NTRS)

    Waters, W. J. (inventor)

    1984-01-01

    An upper plate having ink flow channels and a lower plate having a multicolored pattern are joined. The joining is accomplished without clogging any ink flow paths. A pattern having different colored parts and apertures is formed in a lower plate. Ink flow channels each having respective ink input ports are formed in an upper plate. The ink flow channels are coated with solder mask and the bottom of the upper plate is then coated with solder. The upper and lower plates are pressed together at from 2 to 5 psi and heated to a temperature of from 295 F to 750 F or enough to melt the solder. After the plates have cooled and the pressure is released, the solder mask is removed from the interior passageways by means of a liquid solvent.

  7. Broadband optical mammography: Breast tissue thickness compensation algorithm

    NASA Astrophysics Data System (ADS)

    Anderson, Pamela G.; Sassaroli, Angelo; Kainerstorfer, Jana M.; Krishnamurthy, Nishanth; Fantini, Sergio

    2015-03-01

    We present a method to compensate for breast tissue thickness variability in broadband, continuous-wave, parallel plate optical mammography. Tissue thickness information is relevant for the recovery of chromophore concentrations within the breast using continuous-wave, diffusion-based models that assume the breast to be in slab geometry. This method compensates for the discrepancy between the actual phantom or breast shape and the models assumed slab geometry by approximating the thickness of the probed tissue volume. In this work, we applied our tissue thickness compensation algorithm on a breast shaped, homogeneous, tissue-mimicking phantom. Using the thickness found from our algorithm (referred to as our "estimated thickness") as an input into a continuous-wave, diffusion based model, we recovered the absorption coefficient throughout all scanned pixels in the phantom and found an overall deviation of 12% from the true absorption coefficient. By using the known phantom thickness, we found a strong shape bias within the absorption coefficient recovery and a larger overall deviation of 29%. To test the algorithm on in vivo measurements, we applied this tissue thickness compensation method to a human breast cancer optical mammogram scan. Since the exact thickness of the breast at each pixel is unknown, we compared these results to when a uniform breast thickness is assumed and found a drastic improvement of cancer visualization. This method allows for parallel plate, continuous-wave optical imaging to compensate for the tissue thickness variability at each scanned pixel when modeling the breast data in slab geometry. This compensated thickness is needed as an input to the model in order to accurately map the breast chromophore concentrations and enhance the image contrast of cancer.

  8. 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

    NASA Astrophysics Data System (ADS)

    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 thickness provide a measurement of anomalous uplift or subsidence which we attribute to mantle dynamic topography. We compare our sediment and crustal thickness corrected RDA analysis results with published predictions of mantle dynamic topography from global models.

  9. Crustal Thickness of Iran Inferred from Converted Waves

    NASA Astrophysics Data System (ADS)

    Taghizadeh-Farahmand, Fataneh; Afsari, Narges; Sodoudi, Forough

    2015-02-01

    The Iranian plate is part of the Alpine-Himalayan orogenic belt, which has been formed by the continental collision between the Arabian and Eurasian plates. The present-day Iranian plate is characterized by diverse tectonic domains including mountain belts (e.g. Zagros and Alborz, Kopeh-Dagh) and oceanic plate subduction (e.g. Makran). Here we present the lateral variations of the Moho discontinuity beneath Iran using a detailed P receiver function study. Our results allow for more precise estimations of the crustal thickness and enable us to provide a detailed Moho depth map for all of Iran for the first time. We used the teleseismic events recorded from 1995 to 2011 at 77 national permanent stations (24 broadband and 53 short period stations). Our results show significant variations in the crustal thickness, which are related to the different geological features within Iran. In general, the average crustal thickness beneath Iran is about 40-45 km. A relatively thick crust of about 54 ± 2 km due to the shortening is observed beneath the Alborz mountain ranges. The crust beneath the Alborz zone shows a thickness changing from 47 ± 2 to 45 ± 2 km from west to east and reaches a thickness of about 50 ± 2 km beneath the Kopeh-Dagh mountain range. We find the thinnest crust of about 33 ± 2 km beneath the Makran subduction zone in southeast Iran showing a normal continental crust, which has not been influenced by collisional processes. The thickest crust (~66 ± 2 km) is locally observed beneath the Sanandaj-Sirjan Zone, which is considered the suture zone of the collision between the Arabian and Eurasian plates.

  10. Measuring coal thickness

    NASA Technical Reports Server (NTRS)

    Barker, C.; Blaine, J.; Geller, G.; Robinson, R.; Summers, D.; Tyler, J.

    1980-01-01

    Laboratory tested concept, for measuring thickness of overhead coal using noncontacting sensor system coupled to controller and high pressure water jet, allows mining machines to remove virtually all coal from mine roofs without danger of cutting into overlying rock.

  11. Elastic theory of unconstrained non-Euclidean plates

    E-print Network

    Efi Efrati; Eran Sharon; Raz Kupferman

    2008-10-14

    Non-Euclidean plates are a subset of the class of elastic bodies having no stress-free configuration. Such bodies exhibit residual stress when relaxed from all external constraints, and may assume complicated equilibrium shapes even in the absence of external forces. In this work we present a mathematical framework for such bodies in terms of a covariant theory of linear elasticity, valid for large displacements. We propose the concept of non-Euclidean plates to approximate many naturally formed thin elastic structures. We derive a thin plate theory, which is a generalization of existing linear plate theories, valid for large displacements but small strains, and arbitrary intrinsic geometry. We study a particular example of a hemispherical plate. We show the occurrence of a spontaneous buckling transition from a stretching dominated configuration to bending dominated configurations, under variation of the plate thickness.

  12. Plate Wave Resonance with Air-Coupled Ultrasonics

    NASA Astrophysics Data System (ADS)

    Bar, H. N.; Dayal, V.; Barnard, D.; Hsu, D. K.

    2010-02-01

    Air-coupled ultrasonic transducers can excite plate waves in metals and composites. The coincidence effect, i.e., the wave vector of plate wave coincides with projection of exciting airborne sound vector, leads to a resonance which strongly amplifies the sound transmission through the plate. The resonance depends on the angle of incidence and the frequency. In the present study, the incidence angle for maximum transmission (?max) is measured in plates of steel, aluminum, carbon fiber reinforced composites and honeycomb sandwich panels. The variations of (?max) with plate thickness are compared with theoretical values in steel, aluminum and quasi-isotropic carbon fiber composites. The enhanced transmission of air-coupled ultrasound at oblique incidence can substantially improve the probability of flaw detection in plates and especially in honeycomb structures. Experimental air-coupled ultrasonic scan of subtle flaws in CFRP laminates showed definite improvement of signal-to-noise ratio with oblique incidence at ?max.

  13. Response of a slotted plate flow meter to horizontal two phase flow

    E-print Network

    Muralidharan, Vasanth

    2005-02-17

    standard orifice plate flow meter and then with a venturi. The effects of varying the upstream quality of the two-phase flow on the differential pressure and the coefficient of discharge of the slotted plates, the standard orifice plate and the venturi...

  14. Advanced zone plate antenna design

    NASA Astrophysics Data System (ADS)

    Wiltse, James C.

    2000-12-01

    The phase-correcting Fresnel zone plate antenna has been studied extensively at microwave and millimeter-wave frequencies in the past few years, in part because it offers advantages of low weight, cost, and loss. Scores of articles have appeared describing fundamental characteristics and methods of improving the efficiency, gain, and multiple- frequency band performance. As a result of these studies, one can now optimize the design, and an optimized zone plate antenna can provide performance superior to a standard lens or paraboloid antenna, especially at millimeter wavelengths. There are many differences between performance at optical wavelengths and microwaves/millimeter-waves, and these differences are described. A new planar design with non- parallel surfaces is discussed. This configuration offers further improvement in diffraction efficiency.

  15. White-light scanning interferometer for absolute nano-scale gap thickness measurement

    E-print Network

    Xu, Zhiguang

    A special configuration of white-light scanning interferometer is described for measuring the absolute air gap thickness between two planar plates brought into close proximity. The measured gap is not located in any ...

  16. Teaching Box: Evidence for Plate Tectonics

    NSDL National Science Digital Library

    This Teaching Box is an online assembly of interrelated learning concepts that focuses on finding the evidence for plate tectonics. Digital resources, education standards, and comprehensive lesson plans are combined to provide an inquiry-based exploration of each of three lines of evidence for plate tectonics: fossil distribution, locations, depths, and types of earthquakes; and locations and types of volcanoes. For each line of evidence there is a map showing supporting concepts and their associated standards, preconceptions, lessons organized into teachable units, and a reference section describing the resources used in the box. An introductory activity is also included to engage the students and to provide a segue into the theory.

  17. Taub, Rindler, and the static plate

    Microsoft Academic Search

    A F F Teixeira

    2005-01-01

    An infinite 3D plate of homogeneous incompressible fluid is considered, with\\u000afinite thickness, together with a 2D infinite homogeneous mass in its centre.\\u000aEinstein equations are exactly solved, in the interior of the 3D mass. The\\u000asolution is joined to the exterior vacuum metric of Taub. Every value for the\\u000a2D mass, positive or negative, allows a perfect junction. Also

  18. WFPDB: European Plate Archives

    NASA Astrophysics Data System (ADS)

    Tsvetkov, Milcho

    2007-08-01

    The Wide-Field Plate Database (WFPDB) gives an inventory of all wide-field (>~ 1 sq. deg) photographic observations archived in astronomical institutions over the world. So it facilitates and stimulates their use and preservation as a valuable source of information for future investigations in astronomy. At present WFPDB manages plate-index information for 25% of all existing plates providing on-line access from Sofia (http://www.skyarchive.org/search) and in CDS, Strasbourg. Here we present the new development of WFPDB as an instrument for searching of long term brightness variations of different sky objects stressing on the European photographic plate collections (from existing 2 million wide-field plates more than 55% are in Europe: Germany, Russia, Ukraine, Italy, Czech Republic, etc.). We comment examples of digitization (with flatbed scanners) of the European plate archives in Sonneberg, Pulkovo, Asiago, Byurakan, Bamberg, etc. and virtual links of WFPDB with European AVO, ADS, IBVS.

  19. Industrialization of the ion plating process

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1976-01-01

    A new process referred to as ion plating by induction heating (IPIH) is described, which combines the advantages of both ion plating and induction heating. The IPIH apparatus consists of the specimen (cathode) to be coated and the evaporation heating source, which is a ceramic crucible containing the metal to be heated. The specimen is an internal part of the high-voltage ceramic-metal vacuum feedthrough and is connected to the negative terminal of the high-voltage power supply, the positive terminal of the power supply being grounded. The plating conditions are the same as those most commonly used in industrial ion plating. A number of metals - such as nickel, iron, platinum - which were practically impossible to deposit by resistance heating evaporation can now be effectively evaporated and deposited to any desired thickness. Excellent adherence is observed for many metals deposited on various metal surfaces in thicknesses from 0.15 to 50 microns, regardless of the materials selected for coating and substrate.

  20. Spreading continents kick-started plate tectonics.

    PubMed

    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. PMID:25230662

  1. Geology - Plate Tectonics

    NSDL National Science Digital Library

    Visitors to this site can learn about the theory of plate tectonics, the history of its development, and the mechanisms that drive the formation, movement, and destruction of continents and tectonic plates. A selection of animations depicts the movements of crustal plates and continents through time. Each animation is accompanied by an interactive time scale that provides links to descriptions of the geology and paleontology of the selected era or period.

  2. 49 CFR 229.85 - Doors and cover plates marked “Danger”.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System § 229.85 Doors and cover plates marked “Danger”. All doors and cover plates...

  3. 49 CFR 229.85 - Doors and cover plates marked “Danger”.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System § 229.85 Doors and cover plates marked “Danger”. All doors and cover plates...

  4. Plate Motion Calculator

    NSDL National Science Digital Library

    Lou Estey

    This program calculates tectonic plate motion at any location on Earth using one or more plate motion models. The possible plate motion models are GSRM v1.2 (2004), CGPS (2004), HS3-NUVEL1A, REVEL 2000, APKIM2000.0, HS2-NUVEL1A, NUVEL 1A, NUVEL 1, and two models for ITRF2000. Plates or frames are selected from dropdown lists or can be entered by the user. Position coordinates can be entered in geographic coordinates (decimal degrees, or degrees/minutes/seconds) or in WGS84 cartesian XYZ, as either a single point or multiple points.

  5. Standardized performance tests of collectors of solar thermal energy: A selectively coated, flat-plate copper collector with one transparent cover and a tube-to-tube spacing of 5 5/8 inches

    NASA Technical Reports Server (NTRS)

    1976-01-01

    This preliminary data report gives basic test results of a flat-plate solar collector whose performance was determined in the NASA-Lewis solar simulator. The collector was tested over ranges of inlet temperatures, fluxes and coolant flow rates. Collector efficiency is correlated in terms of inlet temperature and flux level.

  6. Standard performance tests of collectors of solar thermal energy: A selectively coated, flat-plate copper collector with one transparent cover and a tube-to-tube spacing of 3-7/8 inches

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Basic test results are given of a flat-plate solar collector whose performance was determined in the NASA-Lewis solar simulator. The collector was tested over ranges of inlet temperatures, fluxes, and coolant flow rates. Collector efficiency is correlated in terms of inlet temperature and flux level.

  7. Compression Behaviors of Thickness-Reduced Steel Pipes Repaired with Underwater Welds

    Microsoft Academic Search

    X. Chen; Y. Kitane; Y. Itoh

    2011-01-01

    Underwater welding is commonly used to repair corroded offshore steel structures. Corrosion-damaged portions are covered by welded patch plates. According to the current design manual, a thickness of patch plate and a weld length can be determined. However, different weld patterns can be designed to achieve the same required weld length. In order to examine the effectiveness of these different

  8. Author's personal copy Plate tectonic reconstructions with continuously closing plates$

    E-print Network

    Bower, Dan J.

    Author's personal copy Plate tectonic reconstructions with continuously closing plates$ Michael May 2011 Keywords: Geodynamics Plate tectonics a b s t r a c t We present a new algorithm for modeling margins and plates, traditional global plate tectonic reconstructions have become inadequate

  9. Liquid thickness gauge

    NASA Astrophysics Data System (ADS)

    Weinstein, Leonard M.

    1988-08-01

    A method and apparatus are developed to measure the thickness of a liquid on a surface independent of liquid conductivity. Two pairs of round, corrosion resistant wires are mounted in an insulating material such that the cross-sectional area of each wire is flush with and normal to the surface. The resistance between each pair of wires is measured using two ac resistance measuring circuits, in which the ratio of the outputs of the two resistance measuring circuits is indicative of the thickness of the liquid on the surface.

  10. COMPPAP - COMPOSITE PLATE BUCKLING ANALYSIS PROGRAM (UNIX VERSION)

    NASA Technical Reports Server (NTRS)

    Smith, J. P.

    1994-01-01

    The Composite Plate Buckling Analysis Program (COMPPAP) was written to help engineers determine buckling loads of orthotropic (or isotropic) irregularly shaped plates without requiring hand calculations from design curves or extensive finite element modeling. COMPPAP is a one element finite element program that utilizes high-order displacement functions. The high order of the displacement functions enables the user to produce results more accurate than traditional h-finite elements. This program uses these high-order displacement functions to perform a plane stress analysis of a general plate followed by a buckling calculation based on the stresses found in the plane stress solution. The current version assumes a flat plate (constant thickness) subject to a constant edge load (normal or shear) on one or more edges. COMPPAP uses the power method to find the eigenvalues of the buckling problem. The power method provides an efficient solution when only one eigenvalue is desired. Once the eigenvalue is found, the eigenvector, which corresponds to the plate buckling mode shape, results as a by-product. A positive feature of the power method is that the dominant eigenvalue is the first found, which is this case is the plate buckling load. The reported eigenvalue expresses a load factor to induce plate buckling. COMPPAP is written in ANSI FORTRAN 77. Two machine versions are available from COSMIC: a PC version (MSC-22428), which is for IBM PC 386 series and higher computers and compatibles running MS-DOS; and a UNIX version (MSC-22286). The distribution medium for both machine versions includes source code for both single and double precision versions of COMPPAP. The PC version includes source code which has been optimized for implementation within DOS memory constraints as well as sample executables for both the single and double precision versions of COMPPAP. The double precision versions of COMPPAP have been successfully implemented on an IBM PC 386 compatible running MS-DOS, a Sun4 series computer running SunOS, an HP-9000 series computer running HP-UX, and a CRAY X-MP series computer running UNICOS. COMPPAP requires 1Mb of RAM and the BLAS and LINPACK math libraries, which are included on the distribution medium. The COMPPAP documentation provides instructions for using the commercial post-processing package PATRAN for graphical interpretation of COMPPAP output. The UNIX version includes two electronic versions of the documentation: one in LaTex format and one in PostScript format. The standard distribution medium for the PC version (MSC-22428) is a 5.25 inch 1.2Mb MS-DOS format diskette. The standard distribution medium for the UNIX version (MSC-22286) is a .25 inch streaming magnetic tape cartridge (Sun QIC-24) in UNIX tar format. For the UNIX version, alternate distribution media and formats are available upon request. COMPPAP was developed in 1992.

  11. Bearing misalignment effects on the hydrostatic and hydrodynamic behaviour of gears in fixed clearance end plates

    NASA Astrophysics Data System (ADS)

    Koc, E.

    1994-04-01

    Lubrication and sealing mechanisms of fixed clearance end plates in high-pressure pumps have been analysed theoretically and experimentally. Bearing misalignment was found to be the main lubrication mechanism, and it was effective in determining the gear position between two end plates. The minimum film thickness between the gear end and end plate has been found to depend on the magnitude of the relative tilt of the surfaces and the position of the maximum clearance. The theory developed can predict the film thickness between the end plate and gear end face, and this corresponds very closely to the clearances measured experimentally under a variety of operating conditions.

  12. Effect of adhesive thickness on adhesively bonded T-joint

    NASA Astrophysics Data System (ADS)

    Abdullah, A. R.; Afendi, Mohd; Majid, M. S. Abdul

    2013-12-01

    The aim of this work is to analyze the effect of adhesive thickness on tensile strength of adhesively bonded stainless steel T-joint. Specimens were made from SUS 304 Stainless Steel plate and SUS 304 Stainless Steel perforated plate. Four T-joint specimens with different adhesive thicknesses (0.5, 1.0, 1.5 and 2.0 mm) were made. Experiment result shows T-joint specimen with adhesive thickness of 1.0 mm yield highest maximum load. Identical T-joint specimen jointed by spot welding was also tested. Tensile test shows welded T-Joint had eight times higher tensile load than adhesively bonded T-joint. However, in low pressure application such as urea granulator chamber, high tensile strength is not mandatory. This work is useful for designer in fertilizer industry and others who are searching for alternative to spot welding.

  13. Synthesis and Characterization of Nonbanded U-Nb Plate Material

    Microsoft Academic Search

    R. E. Hackenberg; R. M Aikin; J. A. Balog; B. L. Bingham; R. Casey; A. Casteel; I. Cordova; R. Forsyth; F. G. Garcia; D. Guidry; D. L. Hammon; W. L. Hults; D. R. Korzekwa; A. M. Kelly; M. W. Kolby; K. A. Lao; J. C. Lashley; M. F. Lopez; R. McCabe; D. E. Nye; P. A. Papin; S. W. Quintana; J. L. Smith; D. F. Teter; D. J. Thoma; T. Tucker; P. K. Tubesing; R. R. Trujillo; C. J. Vigil; H. M. Volz

    2007-01-01

    This report describes the synthesis and characterization of four plates, two each of U-5.5Nb and U-7.5Nb (nominal wt%) for aging studies described elsewhere. The plates were induction melted and cast into graphite molds that were unheated and 0.5 inches thick to maximize the cooling rate and minimize large length-scale Nb segregation (banding). Microstructural images and electron microprobe traces observed after

  14. Internet Geography: Plate Tectonics

    NSDL National Science Digital Library

    This site is part of GeoNet Internet Geography, a resource for pre-collegiate British geography students and their instructors. This page focuses on the structure of the Earth and the theory of plate tectonics, including continental drift, plate boundaries, the Ring of Fire, and mountains.

  15. How Do Plates Move?

    NSDL National Science Digital Library

    The representation shows the circulation of convection cells in the mantle related to plate movement. A static cross-sectional diagram and accompanying text illustrates the how material heated by the core rises and then sinks when it eventually cools down and attributes this cycle of heating and cooling to tectonic plate movement.

  16. Compton Thick AGN

    NASA Astrophysics Data System (ADS)

    Levenson, N. A.

    2014-07-01

    Compton thick active galactic nuclei (AGN), which are obscured by column density NH > 1.5 × 104 cm-2, can be difficult to identify. They are certainly cosmically significant, both in producing the observed cosmic X-ray background, and in providing a location where black hole growth is hidden from view. Here I review some recent results from surveys that provide indications of Compton thick AGN, considering X-ray, radio, and infrared selection techniques. I also offer a caution against using mid-infrared silicate features to measure line-of-sight obscuration to active galactic nuclei. Instead, these features better indicate the geometric distribution of dust that the central engine heats. I conclude that the outstanding problem of Compton thick AGN is not the cases where the obscuration is directly associated with the environment of the active nucleus itself, even in the most obscured examples. Instead, we still risk missing the completely buried AGN, which are obscured by large amounts of gas and dust over large solid angles. The solution to finding Compton thick AGN may be to begin the search based on infrared emission and star formation, and then select for nuclear activity.

  17. Plate Tectonics Prof. Thomas Herring

    E-print Network

    Herring, Thomas

    1 Plate Tectonics Prof. Thomas Herring MIT 05/14/02 Lexington HS Plate tectonics 2 Contact/14/02 Lexington HS Plate tectonics 3 Overview · Development of the Plate tectonic theory · Geological Data ­ Sea-floor spreading ­ Fault types from earthquakes ­ Transform faults ­ Today's measurements of plate tectonics 05

  18. Delaminations in composite plates under transverse impact loads - Experimental results

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; He, Ye-Fei; Springer, George S.

    1993-01-01

    Tests were performed measuring the locations and geometries of delaminations in Fiberite T300/976 graphite/epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite/PEEK plates subjected to transverse impact loads. The data provide specific information on the effects of impactor velocity, impactor mass, material, thickness of back ply group, difference in fiber orientation between adjacent ply groups, plate thickness, and impactor nose radius. The data were compared to the results of the Finn-Springer model. The model was found to describe the data with reasonable accuracy.

  19. Finite Element and Plate Theory Modeling of Acoustic Emission Waveforms

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Hamstad, M. A.; Gary, J.; OGallagher, A.

    1998-01-01

    A comparison was made between two approaches to predict acoustic emission waveforms in thin plates. A normal mode solution method for Mindlin plate theory was used to predict the response of the flexural plate mode to a point source, step-function load, applied on the plate surface. The second approach used a dynamic finite element method to model the problem using equations of motion based on exact linear elasticity. Calculations were made using properties for both isotropic (aluminum) and anisotropic (unidirectional graphite/epoxy composite) materials. For simulations of anisotropic plates, propagation along multiple directions was evaluated. In general, agreement between the two theoretical approaches was good. Discrepancies in the waveforms at longer times were caused by differences in reflections from the lateral plate boundaries. These differences resulted from the fact that the two methods used different boundary conditions. At shorter times in the signals, before reflections, the slight discrepancies in the waveforms were attributed to limitations of Mindlin plate theory, which is an approximate plate theory. The advantages of the finite element method are that it used the exact linear elasticity solutions, and that it can be used to model real source conditions and complicated, finite specimen geometries as well as thick plates. These advantages come at a cost of increased computational difficulty, requiring lengthy calculations on workstations or supercomputers. The Mindlin plate theory solutions, meanwhile, can be quickly generated on personal computers. Specimens with finite geometry can also be modeled. However, only limited simple geometries such as circular or rectangular plates can easily be accommodated with the normal mode solution technique. Likewise, very limited source configurations can be modeled and plate theory is applicable only to thin plates.

  20. PLATE TECTONICS USING GIS Understanding plate tectonics using real

    E-print Network

    PLATE TECTONICS USING GIS Understanding plate tectonics using real global data sets pertaining OF THE UPSTATE, SC An afternoon field trip to observe the evidences for plate tectonic history, and to witness

  1. The crustal thickness of Australia

    USGS Publications Warehouse

    Clitheroe, G.; Gudmundsson, O.; Kennett, B.L.N.

    2000-01-01

    We investigate the crustal structure of the Australian continent using the temporary broadband stations of the Skippy and Kimba projects and permanent broadband stations. We isolate near-receiver information, in the form of crustal P-to-S conversions, using the receiver function technique. Stacked receiver functions are inverted for S velocity structure using a Genetic Algorithm approach to Receiver Function Inversion (GARFI). From the resulting velocity models we are able to determine the Moho depth and to classify the width of the crust-mantle transition for 65 broadband stations. Using these results and 51 independent estimates of crustal thickness from refraction and reflection profiles, we present a new, improved, map of Moho depth for the Australian continent. The thinnest crust (25 km) occurs in the Archean Yilgarn Craton in Western Australia; the thickest crust (61 km) occurs in Proterozoic central Australia. The average crustal thickness is 38.8 km (standard deviation 6.2 km). Interpolation error estimates are made using kriging and fall into the range 2.5-7.0 km. We find generally good agreement between the depth to the seismologically defined Moho and xenolith-derived estimates of crustal thickness beneath northeastern Australia. However, beneath the Lachlan Fold Belt the estimates are not in agreement, and it is possible that the two techniques are mapping differing parts of a broad Moho transition zone. The Archean cratons of Western Australia appear to have remained largely stable since cratonization, reflected in only slight variation of Moho depth. The largely Proterozoic center of Australia shows relatively thicker crust overall as well as major Moho offsets. We see evidence of the margin of the contact between the Precambrian craton and the Tasman Orogen, referred to as the Tasman Line. Copyright 2000 by the American Geophysical Union.

  2. Reconstruction of the acoustic impedance profile in a plate using an inverse spectral procedure.

    PubMed

    Kawashima, Katsuhiro

    2012-02-01

    An inverse spectral procedure was applied to reconstruct the acoustic impedance profile along the thickness direction of a plate using its thickness resonance frequencies, density and thickness. For a successful reconstruction, the material-property profile must be symmetric about the mid-plane of the plate. Several cases of numerical simulations, including plates with a few layers and with a high number of layers are described. The calculated resonance frequencies were used to reconstruct the acoustic impedance profile, a process that was successful for all cases. We assume that a plate with a high number of layers, each with a different but constant acoustic impedance, simulates a plate with a smoothly varying acoustic impedance profile. It can be concluded that such a plate, which generates small, virtually undetectable, internally reflected waves, can also be reconstructed. In the special case of a plate of unknown thickness and unknown but constant density, the method is still useful, because a relative variation of the material property can be reconstructed using only the resonance frequencies. An experiment using a resonance-mode electromagnetic acoustic transducer (resonance-mode EMAT) is also described. EMAT is a non-contact ultrasonic method that can measure thickness resonance frequencies, making it appropriate for this method. Some examples of applications are measurement of the temperature profile inside a rolled metal sheet, measurement of a clad metal plate, and monitoring of a metal casting. PMID:21944992

  3. Plate forming and break down pizza box

    DOEpatents

    Pantisano, Frank (411 Linda Ave., Blackwood, NJ 08012); Devine, Scott M. (B7 Fairways Apartments, Blackwood, NJ 08012)

    1992-01-01

    A standard corrugated paper pizza box is provided with slit cuts cut through the top panel of the pizza box in a shape to form four circular serving plates with a beveled raised edge and cross slit cuts through the bottom panel of the pizza box separating the box into four essentially equal portions for easy disposal.

  4. An experimental study of normal and oblique impact of hard-core projectile on single and layered plates

    Microsoft Academic Search

    N. K. Gupta; V. Madhu

    1997-01-01

    An experimental study of the normal and oblique impact of armour-piercing projectiles on single and layered plates of mild steel, RHA steel and aluminium is presented. The projectiles were fired at an impact velocity of ?800–880 m s?1. The plate thickness varied in the range 4.7–40 mm and the ratio of the plate thickness to the diameter of the projectile

  5. Normal-pressure Tests of Circular Plates with Clamped Edges

    NASA Technical Reports Server (NTRS)

    Mcpherson, Albert E; Ramberg, Walter; Levy, Samuel

    1942-01-01

    A fixture is described for making normal-pressure tests of flat plates 5 inches in diameter in which particular care was taken to obtain rigid clamping at the edges. Results are given for 19 plates, ranging in thickness from 0.015 to 0.072 inch. The center deflections and the extreme-fiber stresses at low pressures were found to agree with theoretical values; the center deflections at high pressures were 4 to 12 percent greater than the theoretical values. Empirical curves are derived of the pressure for the beginning of permanent set as a function of the dimensions of the plate and the tensile properties of the material.

  6. Normal-Pressure Tests of Circular Plates with Clamped Edges

    NASA Technical Reports Server (NTRS)

    Mcpherson, Albert E; Ramberg, Walter; Levy, Samuel

    1942-01-01

    A fixture is described for making normal-pressure tests of flat plates 5 inches in diameter in which particular care was taken to obtain rigid clamping at the edges. Results are given for 19 plates, ranging in thickness form 0.015 to 0.072 inch. The center deflections and the extreme-fiber stresses at low pressures were found to agree with theoretical values; the center deflections at high pressures were 4 to 12 percent greater than the theoretical values. Empirical curves are derived of the pressure for the beginning of the permanent set as a function of the dimensions of the plate and the tensile properties of the material.

  7. New hybrid quadrilateral finite element for Mindlin plate

    NASA Astrophysics Data System (ADS)

    Chin, Yi; Zhang, Jingyu

    1994-02-01

    A new quadrilateral plate element concerning the effect of transverse shear strain was presented. It was derived from the hybrid finite element model based on the principles of virtual work. The outstanding advantage of this element was to use more rational trial functions of the displacements. For this reason, every variety of plate deformation can be simulated really while the least degrees of freedom was employed. A wide range of numerical tests was conducted and the results illustrate that this element has a very wide application scope to the thickness of plates and satisfactory accuracy can be obtained by coarse mesh for all kinds of examples.

  8. Power flow analysis of two coupled plates with arbitrary characteristics

    NASA Technical Reports Server (NTRS)

    Cuschieri, J. M.

    1988-01-01

    The limitation of keeping two plates identical is removed and the vibrational power input and output are evaluated for different area ratios, plate thickness ratios, and for different values of the structural damping loss factor for the source plate (plate with excitation) and the receiver plate. In performing this parametric analysis, the source plate characteristics are kept constant. The purpose of this parametric analysis is to be able to determine the most critical parameters that influence the flow of vibrational power from the source plate to the receiver plate. In the case of the structural damping parametric analysis, the influence of changes in the source plate damping is also investigated. As was done previously, results obtained from the mobility power flow approach will be compared to results obtained using a statistical energy analysis (SEA) approach. The significance of the power flow results are discussed together with a discussion and a comparison between SEA results and the mobility power flow results. Furthermore, the benefits that can be derived from using the mobility power flow approach, are also examined.

  9. Mode selection of guided waves for ultrasonic inspection of gas pipelines with thick coating

    Microsoft Academic Search

    E. Pan; J. Rogers; S. K. Datta; A. H. Shah

    1999-01-01

    Mode selection of guided waves in an elastic steel plate with thick coating layer has been studied here. Effect of both thick elastic coating and damping of the coating layer on the dispersion and mode shapes has been investigated and modes that are less affected by elastic coating and damping have been identified. For modeling the viscoelastic behavior of the

  10. Influence of cortical bone thickness on the ultrasound velocity

    PubMed Central

    Mandarano-Filho, Luiz Garcia; Bezuti, Márcio Takey; Mazzer, Nilton; Barbieri, Cláudio Henrique

    2012-01-01

    Objective An experimental in vitro study was carried out to evaluate the influence of cortical bone thickness on ultrasound propagation velocity. Methods Sixty bone plates were used, made from bovine femurs, with thickness ranging from 1 to 6 mm (10 of each). The ultrasound velocity measurements were performed using a device specially designed for this purpose, in an underwater acoustic tank and with direct contact using contact gel. The transducers were positioned in two ways: on opposite sides, with the bone between them, for the transverse measurement; and parallel to each other, on the same side of the bone plates, for the axial measurements. Results In the axial transmission mode, the ultrasound velocity speed increased with cortical bone thickness, regardless of the distance between the transducers, up to a thickness of 5 mm, then remained constant thereafter. There were no changes in velocity when the transverse measures were made. Conclusion Ultrasound velocity increased with cortical bone thickness in the axial transmission mode, until the thickness surpasses the wavelength, after which point it remained constant. Level of Evidence: Experimental Study. PMID:24453601

  11. Molecular plating of actinides on thin backings

    NASA Astrophysics Data System (ADS)

    Greene, John P.; Ahmad, Irshad

    2008-06-01

    Actinide targets on thick and thin backings are needed for experiments at heavy-ion accelerators. One of the efficient ways to prepare such targets is by molecular plating. Although many laboratories have successfully prepared targets on thick backings by this technique, it is quite difficult to make targets on thin backings (100 ?g/cm 2 up to 1 mg/cm 2). In recent years, we have plated targets on thin Ni and carbon backings, for example 234U targets on a 200 ?g/cm 2 Ni backing. The Ni foils, evaporated on a copper substrate, are available commercially. We used these foils to plate 234U and afterwards we removed the copper by dissolving it in a mixture of ammoniacal trichloroacetic acid. In this way 400 ?g/cm 2 234U targets were prepared on a 200 ?g/cm 2 Ni backing. A 100 ?g/cm 2 243Am target was prepared by plating onto a 75 ?g/cm 2 carbon film left on its glass substrate for later floating. We found that a plating cell made from Teflon was difficult to use because it scratched the C film producing a liquid leak at the joint of the column and the C film. This sealing surface needs to be extremely smooth to avoid leakage. A column made of Delrin™ was then tried and did not produce any scratch on the carbon film surface. This column was used to prepare 100 ?g/cm 2 243Am targets. Details of the technique will be presented.

  12. Earthquakes and plate tectonics.

    USGS Publications Warehouse

    Spall, H.

    1982-01-01

    Earthquakes occur at the following three kinds of plate boundary: ocean ridges where the plates are pulled apart, margins where the plates scrape past one another, and margins where one plate is thrust under the other. Thus, we can predict the general regions on the earth's surface where we can expect large earthquakes in the future. We know that each year about 140 earthquakes of magnitude 6 or greater will occur within this area which is 10% of the earth's surface. But on a worldwide basis we cannot say with much accuracy when these events will occur. The reason is that the processes in plate tectonics have been going on for millions of years. Averaged over this interval, plate motions amount to several mm per year. But at any instant in geologic time, for example the year 1982, we do not know, exactly where we are in the worldwide cycle of strain build-up and strain release. Only by monitoring the stress and strain in small areas, for instance, the San Andreas fault, in great detail can we hope to predict when renewed activity in that part of the plate tectonics arena is likely to take place. -from Author

  13. Plate Tectonics Jigsaw

    NSDL National Science Digital Library

    Anne Egger

    This activity is a slight variation on an original activity, Discovering Plate Boundaries, developed by Dale Sawyer at Rice University. I made different maps, including more detail in all of the datasets, and used a different map projection, but otherwise the general progression of the activity is the same. More information about jigsaw activities in general can be found in the Jigsaws module. The activity occurs in several sections, which can be completed in one or multiple classes. In the first section, students are divided into "specialist" groups, and each group is given a global map with a single dataset: global seismicity, volcanoes, topography, age of the seafloor, and free-air gravity. Each student is also given a map of plate boundaries. Their task in the specialist group is to become familiar with their dataset and develop categories of plate boundaries based only on their dataset. Each group then presents their results to the class. In the second section, students reorganize into groups with 1-2 of each type of specialist per group. Each new group is given a plate, and they combine their different datasets on that one plate and look for patterns. Again, each plate group presents to the class. The common patterns and connections between the different datasets quickly become apparent, and the final section of the activity involves a short lecture from the instructor about types of plate boundaries and why the common features are generated at those plate boundaries. A follow-up section or class involves using a problem-solving approach to explain the areas that don't "fit" into the typical boundary types - intra-plate volcanism, earthquakes in the Eastern California Shear Zone, etc.

  14. Plate Tectonics at Work

    NSDL National Science Digital Library

    This is a brief description of the results of plate movement according to the Theory of Plate Tectonics. It explains how divergence at the mid-ocean ridges accounts for the discoveries of Harry Hess. The site also refers to the invention of the magnetometer and the discovery of the young age of the ocean floor basalt. It concludes that these are the kinds of discoveries and thinking that ultimately led to the development of the theory of plate tectonics and that in just a few decades, have greatly changed our view of and notions about our planet and the sciences that attempt to explain its existence and development.

  15. Seedless Fill-Up of the Damascene Structure Only by Copper Electroless Plating

    NASA Astrophysics Data System (ADS)

    Kim, Jae Jeong; Cha, Seung Hwan; Lee, Young-Soo

    2003-08-01

    We attempted to fill up seedlessly the damascene pattern in ULSI interconnection only by Cu electroless plating. Cu2O content, which was generally detected in Cu electroless plating, was removed through controlling the plating temperature. Optimum control in electrolyte concentration and plating temperature leaded to good characteristics of electrolessly plated Cu with 2.1 ??\\cdotcm resistivity, 8.9 nm rms roughness at 160 nm thickness, good adhesion and 10 nm/min deposition rate. The optimum condition was successfully applied to a damascene pattern with aspect ratio of 3 and via size of 0.13 ?m without void and seam.

  16. A Rigorous Derivation of the Equations for the Clamped Biot-Kirchhoff-Love Poroelastic Plate

    NASA Astrophysics Data System (ADS)

    Marciniak-Czochra, Anna; Mikeli?, Andro

    2015-03-01

    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 two dimensional 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 Laplacian of the vertical deflection of the plate and of the elastic in-plane compression term.

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

    E-print Network

    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.

  18. Effect of 1partial thickness actuation on stress concentration reduction near a hole

    NASA Astrophysics Data System (ADS)

    Sensharma, P. K.; Kadivar, M. H.; Haftka, R. T.

    1994-04-01

    Recently, there has been much interest in adaptive structures that can respond to a varying environment by changing their properties. Piezoelectric materials and shape memory alloys (SMA) are often used as partial thickness actuators to create such adaptivity by applied energy, usually electric curent. These actuators can be used to inducce strains in a structure and reduce stresses in regions of high stress concentration. Two of the present authors show that axisymmetric actuation strains applied troughout the thickness of a plate with a hole can reduce the stress concentration factor (SCF) in an isotropic plate from 3 to 2. However, in most cases actuators are expected to be bonded to or embedded in the plate, so that the actuation strains are applied in the actuators and not directly in the plate. The objective of this note is to show that such partial-thickness actuation cannot be used to reduce the stress concentration factor with axisymmetric actuations strain distribution.

  19. Development status of thick film photoresist for semiconductor packaging

    NASA Astrophysics Data System (ADS)

    Misumi, Koichi; Saito, Koji; Obiya, Hiroyuki

    2005-05-01

    In recent years, the demand of thick film photoresists for both copper metal posts and solder bump has been rising for Wafer Level Chip Size Package (WL-CSP) applications. The polymerizing negative tone photoresist, typified by Dry-film photoresist, for metal post applications is currently the mainstream method, but difficulty in removal, thickness selectivity, scaling of chip size and high definition requirements has made the development of a positive tone photoresist for thick film application a necessity. However, the sensitization of a conventional DNQ positive tone photoresist system was difficult due to the nature of the reaction mechanism. In order to meet these requirements, a study was made with a new approach with a positive tone chemically amplified photoresist system, and will be explained in detail in this paper. In general, DNQ type thick photoresist for plating process is developed from the positive tone photoresist platform for semiconductor application through optimization of resist composition and improvement of cracking during the plating process through addition of plasticizers. Inherent performance or compatibility issues with the conventional plasticizer in positive tone chemically amplified photoresist have lead to the development of plasticizer with protecting group. This modification of composition has improved the phtoresist for cracks and swelling of bumps after plating. This is the first chemically amplified photo resist designed for use in the consumer product manufacturing industry.

  20. Integrated high-temperature piezoelectric plate acoustic wave transducers using mode conversion.

    PubMed

    Wu, Kuo-Ting; Kobayashi, Makiko; Jen, Cheng-Kuei

    2009-06-01

    Piezoelectric thick (>66 microm) films have been directly coated onto aluminum (Al) substrates using a sol-gel spray technique. With top electrode, these films serve as integrated ultrasonic transducers (IUT), which normally operate as thickness longitudinal wave transducers. When such IUT are located at the edges of the metallic plates, they can excite and detect symmetrical, antisymmetric and shear horizontal types of plate acoustic waves (PAW) using mode conversion methods. In 2 mm thick Al plates, 2 line defects of 1 mm width and 1 mm depth were clearly detected at temperatures up to 150 degrees C in pulse-echo mode. Results indicated that, for 2 mm thick aluminum plates, shear horizontal PAW were the best for the line defect detection. Also, the experimental results agree well with those obtained by a finite-difference-based method. PMID:19574129

  1. Line narrowing of terahertz vibrational modes for organic thin polycrystalline films within a parallel plate waveguide

    E-print Network

    recently been demonstrated by the THz-TDS characterization of nanometer thick water layers.9 In addition-TDS Refs. 7­9 is shown in Fig. 1. The PPWG assembly consists of two copper plates with identical dimen

  2. Coupling volcanism and tectonics along divergent plate boundaries: collapsed rifts from Central Afar, Ethiopia

    Microsoft Academic Search

    Valerio Acocella

    2010-01-01

    Magma along divergent plate boundaries is erupted from fissures or vents from central volcanoes, with limited impact on rift architecture. Here I summarize the geological and structural features accompanying the eruption of part of a km-thick volcanic sequence (\\

  3. Start-up vortex flow past an accelerated flat plate

    NASA Astrophysics Data System (ADS)

    Xu, Ling; Nitsche, Monika

    2015-03-01

    Viscous flow past a finite flat plate accelerating in the direction normal to itself is studied numerically. The plate moves with nondimensional speed tp, where p = 0, 1/2, 1, 2. The work focuses on resolving the flow at early to moderately large times and determining the dependence on the acceleration parameter p. Three stages in the vortex evolution are identified and quantified. The first stage, referred to as the Rayleigh stage [Luchini and Tognaccini, "The start-up vortex issuing from a semi-infinite flat plate," J. Fluid Mech. 455, 175-193 (2002)], consists of a vortical boundary layer of roughly uniform thickness surrounding the plate and its tip, without any separating streamlines. This stage is present only for p > 0, for a time-interval that scales like p3, as p ? 0. The second stage is one of self-similar growth. The vortex trajectory and circulation satisfy inviscid scaling laws, the boundary layer thickness satisfies viscous laws. The self-similar trajectory starts immediately after the Rayleigh stage ends and lasts until the plate has moved a distance d = 0.5 to 1 times its length. Finally, in the third stage, the image vorticity due to the finite plate length becomes relevant and the flow departs from self-similar growth. The onset of an instability in the outer spiral vortex turns is also observed, however, at least for the zero-thickness plate considered here, it is shown to be easily triggered numerically by underresolution. The present numerical results are compared with experimental results of Pullin and Perry ["Some flow visualization experiments on the starting vortex," J. Fluid Mech. 97, 239-255 (1980)], and numerical results of Koumoutsakos and Shiels ["Simulations of the viscous flow normal to an impulsively started and uniformly accelerated flat plate," J. Fluid Mech. 328, 177-227 (1996)].

  4. Farallon Plate Remnants

    NSDL National Science Digital Library

    NASA/Goddard Space Flight Center Scientific Visualization Studio

    This image and short video from the NASA's Scientific Visualization Studio shows the remnants of the Farallon Plate based on seismic tomography studies. The studies were conducted by Hans-Peter Bunge at Princeton University in 2000.

  5. Plate Tectonics Learning Module

    NSDL National Science Digital Library

    Rita Haberlin

    This plate tectonics unit was designed to be used with a college course in physical geography. Subject matter covered includes: the development of the theory including Wegener's Continental Drift Hypothesis and the existence of Pangaea, Harry Hess and his work on sea-floor spreading, and the final theory. It points out that global features such as deep oceanic trenches, mid-ocean ridges, volcanic activity, and the location of earthquake epicenters can now be related to the story of plate tectonics, since most geological activity occurs along plate boundaries. Divergent, convergent and transform plate boundaries are discussed in detail. This module contains a study guide and outline notes, study questions, and practice quizzes. One feature of the module is a web exploration section with links to twelve outside sites that augment the instruction.

  6. elementsair ceramic plate

    E-print Network

    earth elementsair L ceramic plate Thermoelectric Module Construction for Low Temperature Gradient Power Generation Y. Meydbray, R. Singh, Ali Shakouri University of California at Santa Cruz, Electrical related carbon dioxide emissions are the largest contributors to greenhouse gasses [1]. Thermoelectric

  7. Tectonic Plate Movement.

    ERIC Educational Resources Information Center

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  8. How Plates Move

    NSDL National Science Digital Library

    This information on the two major types of plate interaction and the resulting features discusses the Mid Atlantic Ridge and the mid-ocean ridges in connection with divergence and ocean trenches and connects the Pacific Ring of Fire to the concept of subduction. Volcanic activity as a result of subduction is also covered. The site also features links to goals, objectives, and materials for a hands-on lesson on how plates move.

  9. Fractal generalized zone plates

    Microsoft Academic Search

    Omel Mendoza-Yero; Mercedes Fernández-Alonso; Gladys Mínguez-Vega; Jesús Lancis; Vicent Climent; Juan A. Monsoriu

    2009-01-01

    The construction of fractal generalized zone plates (FraGZPs) from a set of periodic diffractive optical elements with circular symmetry is proposed. This allows us to increase the number of foci of a conventional fractal zone plate (FraZP), keeping the self-similarity property within the axial irradiance. The focusing properties of these fractal diffractive optical elements for points not only along but

  10. Fractal multifiber microchannel plates

    NASA Technical Reports Server (NTRS)

    Cook, Lee M.; Feller, W. B.; Kenter, Almus T.; Chappell, Jon H.

    1992-01-01

    The construction and performance of microchannel plates (MCPs) made using fractal tiling mehtods are reviewed. MCPs with 40 mm active areas having near-perfect channel ordering were produced. These plates demonstrated electrical performance characteristics equivalent to conventionally constructed MCPs. These apparently are the first MCPs which have a sufficiently high degree of order to permit single channel addressability. Potential applications for these devices and the prospects for further development are discussed.

  11. Partial Thickness Rotator Cuff Tears: Current Concepts

    PubMed Central

    Matthewson, Graeme; Beach, Cara J.; Nelson, Atiba A.; Woodmass, Jarret M.; Ono, Yohei; Boorman, Richard S.; Lo, Ian K. Y.; Thornton, Gail M.

    2015-01-01

    Partial thickness rotator cuff tears are a common cause of pain in the adult shoulder. Despite their high prevalence, the diagnosis and treatment of partial thickness rotator cuff tears remains controversial. While recent studies have helped to elucidate the anatomy and natural history of disease progression, the optimal treatment, both nonoperative and operative, is unclear. Although the advent of arthroscopy has improved the accuracy of the diagnosis of partial thickness rotator cuff tears, the number of surgical techniques used to repair these tears has also increased. While multiple repair techniques have been described, there is currently no significant clinical evidence supporting more complex surgical techniques over standard rotator cuff repair. Further research is required to determine the clinical indications for surgical and nonsurgical management, when formal rotator cuff repair is specifically indicated and when biologic adjunctive therapy may be utilized. PMID:26171251

  12. Ultrasonic testing of adhesive bonds of thick composites with applications to wind turbine blades

    NASA Astrophysics Data System (ADS)

    Chakrapani, Sunil Kishore; Dayal, Vinay; Krafka, Ryan; Eldal, Aaron

    2012-05-01

    This paper discusses the use of pulse echo based ultrasonic testing for the inspection of adhesive bonds between very thick composite plates (thickness greater than 30 mm). Large wind turbine blades use very thick composite plates for its main structural members, and the inspection of adhesive bond-line is very vital. A wide gamut of samples was created by changing the thickness of plate and the adhesive. The influence of experimental parameters such as frequency on measurement is studied in this paper. Two different frequencies are chosen, and the measurement error bars are determined experimentally. T-Ray measurements were used to verify and correct results, and conclusions are made based on the combined results.

  13. A new triangular finite element for fiber-reinforced composite plates

    E-print Network

    Finkel, Herbert Leslie

    1985-01-01

    December 1985 Major Subject: Mechanical Engineering A NEW TRIANGULAR FINITE ELEMENT FOR FIBER-REINFORCED COMPOSITE PLATES A Thesis by HERBERT LESLIE FINKEL Approved as to style and content by: Joh J. Eng om (Chairman of Committee) Ozden O. Ochoa... force vector Layer in-plane and thickness shear moduli Total thickness of plate Jacobian matrix Element stiffness matrix Triangle area coordinates Vector of body forces Normal and tangential directions Element shape functions Distributed load...

  14. Modeling of composite beams and plates for static and dynamic analysis

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.

    1992-01-01

    A rigorous theory and the corresponding computational algorithms were developed for through-the-thickness analysis of composite plates. This type of analysis is needed in order to find the elastic stiffness constants of a plate. Additionally, the analysis is used to post-process the resulting plate solution in order to find approximate three-dimensional displacement, strain, and stress distributions throughout the plate. It was decided that the variational-asymptotical method (VAM) would serve as a suitable framework in which to solve these types of problems. Work during this reporting period has progressed along two lines: (1) further evaluation of neo-classical plate theory (NCPT) as applied to shear-coupled laminates; and (2) continued modeling of plates with nonuniform thickness.

  15. Magnetostrictive bending of cantilever beams and plates

    NASA Astrophysics Data System (ADS)

    Guerrero, Victor H.; Wetherhold, Robert C.

    2003-11-01

    The models currently used to determine strains, stresses, and deflections in beams and plates made of magnetostrictive films deposited on nonmagnetic substrates are based on the assumption that the film is relatively thin compared to the substrate. Despite the lack of self-consistency and the limitations of these models, they can be used to calculate approximate strains and deflections when the ratio of the thickness of the film to the thickness of the substrate is smaller than about 0.001; even then they do not consistently predict stresses or energies. Unfortunately, the large deflections required in modern applications are only achievable with films that do not satisfy this assumption of relative film thinness, and the results obtained with the traditional models show large errors. In these circumstances it is necessary to introduce robust methods that can be applied regardless of the relative magnitude of the thickness of the film. In this article, one such method is presented. The method represents a self-consistent approach based on the minimization of the total internal energy of a film-substrate system, performed based on the assumption that the magnetostrictive strains can be modeled as anisotropic expansional strains. The expressions obtained using this approach can be used to calculate strains, stresses, deflections, and energies in an accurate way. The method is suitable for generalization to the cases in which the deformation of beams and plates is produced not only due to magnetostriction in the films, but may also include thermal, piezoelectric, or hygroscopic strains.

  16. Buckling transition and boundary layer in non-Euclidean plates

    E-print Network

    Efi Efrati; Eran Sharon; Raz Kupferman

    2009-05-29

    Non-Euclidean plates are thin elastic bodies having no stress-free configuration, hence exhibiting residual stresses in the absence of external constraints. These bodies are endowed with a three-dimensional reference metric, which may not necessarily be immersible in physical space. Here, based on a recently developed theory for such bodies, we characterize the transition from flat to buckled equilibrium configurations at a critical value of the plate thickness. Depending of the reference metric, the buckling transition may be either continuous or discontinuous. In the infinitely thin plate limit, under the assumption that a limiting configuration exists, we show that the limit is a configuration that minimizes the bending content, amongst all configurations with zero stretching content (isometric immersions of the mid-surface). For small but finite plate thickness we show the formation of a boundary layer, whose size scales with the square root of the plate thickness, and whose shape is determined by a balance between stretching and bending energies.

  17. Redesign of Indonesian-made osteosynthesis plates to enhance their mechanical behavior.

    PubMed

    Dewo, P; van der Houwen, E B; Suyitno; Marius, R; Magetsari, R; Verkerke, G J

    2015-02-01

    Mechanical properties determined by fatigue strength, ductility, and toughness are important measures for osteosynthesis plates in order to tolerate some load-bearing situations caused by muscle contractions and weight-bearing effects. Previous study indicated that Indonesian-made plates showed lower mechanical strength compared to the European AO standard plate. High stress under load-bearing situations often starts from surface of the plate; we therefore refined the grain size of the surface by using shot peening and surface mechanical attrition treatment (SMAT). Single cycle bending tests showed that shot-peened and SMAT-treated plates had significantly higher load limit and bending stress compared to the original plates (p<0.05). Weibull analysis confirmed the improvement of proportional load limit of SMAT-treated plates. Fatigue limit also increased upon shot-peening and SMAT treatment (improvement ratio 18% and 27%, respectively). Significant improvement ratio of fatigue tests can be observed in SMAT-treated plates compared to the untreated and shot-peened plates. Fatigue performance demonstrated equivalent results between SMAT-treated and standard plate. These designated that mechanical properties of Indonesian-made plates can be improved upon SMAT treatment leading to significant enhancement of mechanical strength thus is comparable to the standard plate. Our findings highlight the benefits of SMAT treatment to improve mechanical strength of Indonesian-made osteosynthesis plates. PMID:25523978

  18. 10D-2 Integrated Plate Acoustic Wave Transducers Using Mode Conversion

    Microsoft Academic Search

    K.-T. Wu; M. Kobayashi; C.-K. Jen; J.-F. Moisan

    2007-01-01

    Integrated (IUTs) and flexible ultrasonic transducers (FUTs) have been used to generate and receive plate acoustic waves (PAWs) for long distance (up to more than lm) structural health monitoring applications. These IUTs and FUTs were made by sol-gel spray techniques and thickness vibration longitudinal wave transducers. Using mode conversion techniques these transducers located at the edges of the plates could

  19. Buckling of piezoelectric functionally graded plate subjected to electro-mechanical loading

    Microsoft Academic Search

    Priyanka A Jadhav; Kamal M Bajoria

    2012-01-01

    This paper investigates the stability analysis of a functionally graded (FG) plate integrated with a piezoelectric sensor and actuator at the top and bottom faces, subjected to electrical and mechanical loading. The material properties of the FG plates are assumed to be graded along the thickness direction according to simple power law distribution in terms of the volume fraction of

  20. High frequency acoustic transmission loss of perforated plates at normal incidence

    E-print Network

    Papamoschou, Dimitri

    about 1.5 dB for dimensionless hole diameter d/k dependence on plate thickness-to-diameter ratio or porosity. VC 2013 Acoustical Society of America. [http. It consists of a valve body, followed by a muffler comprising perforated plates oriented substantially

  1. Researching of thin-plate mechanoluminescence initiated by thermal deformations resulting from laser pulse action

    Microsoft Academic Search

    Alexander F. Banishev; Vladislav Y. Panchenko; Alexei V. Shishkov

    2002-01-01

    The paper presents the results of study of thin plates and films mechanoluminescence initiated by thermal deformations resulting from high-power laser pulse action. The dependence of excitation threshold and intensity of mechanoluminescence on plates thickness and the dependence of intensity of mechanoluminescence on laser pulse power density were investigated.

  2. Optimum fin geometry in flat plate solar collector systems

    Microsoft Academic Search

    Viorel Badescu

    2006-01-01

    The width and thickness of the fins is optimized by minimizing the cost per unit useful heat flux. The proposed procedure allows computation of the necessary collection surface area. A rather involved, but still simple, flat plate solar collector model is used in the calculations. Model implementation requires a specific geographical location with a detailed meteorological data base available. Both

  3. Characterization of a texture gradient in tantalum plate

    SciTech Connect

    Wright, S.I.; Gray, G.T. III

    1994-11-01

    Clark et al. have shown that significant texture gradients can be produced in rolled tantalum plate and that the strength of the gradient is dependent on the processing path. Texture gradients are often ignored because they are time consuming to characterize and add significant complexity to materials modeling. The variation in texture through the thickness of rolled materials is most commonly measured by sectioning samples to different depths through the thickness of the plate and then measuring the texture from these section planes by X-ray diffraction. A new technique based on automatic indexing of electron backscatter diffraction patterns in the scanning electron microscope enables spatially specific orientations to be measured in a practical manner. This technique allows spatial variations in texture to be measured directly enabling gradients in texture to be investigated in more detail than previously possible. This data can be used directly in coupled finite-element/polycrystal-plasticity models to simulate the effects of variations in texture on the plastic behavior of polycrystals. This work examines the variation in texture through the thickness of a tantalum plate and its resultant effect on the compressive deformation of samples prepared from the plate. The characterization of the texture gradient using the automatic point-by-point measurement technique mentioned above is described in detail. The effect of the gradient on the plastic response of through-thickness compression tests is also discussed.

  4. Piezoelectric Energy Harvesting with a Clamped Circular Plate: Experimental Study

    Microsoft Academic Search

    Sunghwan Kim; William W. Clark; Qing-Ming Wang

    2005-01-01

    In a companion article, a model for a clamped circular unimorph piezoelectric plate has been developed for the purpose of analyzing the influence of geometric design parameters and electrode configuration on the amount of electrical energy that can be harvested from an applied pressure source. It has been shown that the ratio of layer thickness (piezoelectric layer to substrate layer)

  5. A Stabilized Mixed Quadrilateral Plate Bending Element for

    E-print Network

    Daly, Samantha

    ++++==== ++++ ==== ++++==== ++++ ==== ++++ ==== ==== ==== , ,,, Generalized strain-displacement relations #12;11 Generalized stress-strain relations Moment;12 (((( )))) (((( )))) ++++ ==== ---- ==== 12 , 112 2 3 E G tE D D : Bending stiffness, G : Shear stiffness E : Young's modulus, v : Poisson's ratio t : Plate thickness is the shear correction factor to account for non-uniform distribution

  6. Locking plate construct for femoral shaft fractures in skeletally immature patients

    Microsoft Academic Search

    Akram H AMMAD

    Different methods of internal fixation are used in the treatment of femoral shaft fractures. Results of locked plate fixation in adults have been encouraging. A locking plate construct with a standard broad Dynamic Compression Plate (DCP) and 4.5 mm nuts was used in the treatment of femoral shaft fractures in 15 skeletally immature patients. There were 12 boys and three

  7. HETEROTROPHIC PLATE COUNT BACTERIA IN POTABLE WATER: MONITORING METHODS AND APPLICATION

    EPA Science Inventory

    The heterotrophic plate count (HPC), formerly known as the standard plate count, is a useful tool for enumerating bacteria in potable water. his chapter briefly reviews the development of the heterotrophic bacterial plate count for use in water quality measurements in the United ...

  8. Strength of Rectangular Flat Plates Under Edge Compression

    NASA Technical Reports Server (NTRS)

    Schuman, Louis; Back, Goldie

    1931-01-01

    Flat rectangular plates of duralumin, stainless iron, monel metal, and nickel were tested under loads applied at two opposite edges and acting in the plane of the plate. The edges parallel to the direction of loading were supported in V grooves. The plates were all 24 inches long and varied in width from 4 to 24 inches by steps of 4 inches, and in thickness from 0.015 to 0.095 inch by steps of approximately 0.015 inch. There were also a few 1, 2, 3, and 6 inch wide specimens. The loads were applied in the testing machine at the center of a bar which rested along the top of the plate. Load was applied until the plate failed to take any more load. The tests show that the loads carried by the plates generally reached a maximum for the 8 or 12 inch width and that there was relatively small drop in load for the greater widths. Deflection and set measurement perpendicular to the plane of the plate were taken and the form of the buckle determined. The number of buckles were found to correspond in general to that predicted by the theory of buckling of a plate uniformly loaded at two opposite edges and simply supported at the edges.

  9. Theory of Four-Point Direct-Current Potential Drop Measurements on a Metal Plate

    Microsoft Academic Search

    Nicola Bowler

    2006-01-01

    Four-point direct-current potential drop techniques are well-suited for accurate, nondes- tructive measurement of material conductivity (or resistivity). From measurements of poten- tial drop on a large metal plate, the electrical conductivity of the plate can be inferred if the thickness of the plate and the dimensions of the probe are known. In this work, an expression for the voltage measured

  10. Spall fracture characterization of thermosetting and thermoplastic polymer matrix composite plates

    Microsoft Academic Search

    Nobuo Takeda; Haruo Komatsu; Kiyoshi Takahashi

    1993-01-01

    So-called spall fractures (through-the-thickness tensile impact fractures) in simple uniaxial strain were examined for typical glass fiber reinforced thermosetting and thermoplastic polymer composite plates. An exploding foil technique was used to accelerate thin flyer plates towards composite plates to generate spall fractures. For thermosetting polyester composites, different fiber surface treatments were applied to study the effects of interfacial strengths on

  11. BEPLATE emdash simulation of electrochemical plating

    SciTech Connect

    Giles, G.E. (Oak Ridge K-25 Site, TN (USA)); Gray, L.J. (Oak Ridge National Lab., TN (USA)); Bullock, J.S. IV (Oak Ridge Y-12 Plant, TN (USA))

    1990-09-01

    BEPLATE is a FORTRAN code that uses the boundary element method to simulate the electrochemical plating of material on parts, primarily rotating axisymmetric parts. A boundary element technique is used to solve for the local current density and thus the plating rate on the part, which is used to calculate the growth in the plated layer over a user-specified time step. The surface is moved to reflect this growth, and the new surface is used to generate the local current density. This cycle is repeated until the final time specified by the analyst, producing the final plated thickness. BEPLATE includes models for the polarization effects at both the part (cathode) and anode and allows the use of symmetry planes and nonconducting shields. For electroplating simulations, the part shape is normally assumed to be axisymmetric with a centerline along the z-axis. More general part shapes can be analyzed by BEPLATE if the surface growth simulation is not needed. In either case, the shield, anode, and tank geometries are not restricted to specific shapes. This report includes the information required to run BEPLATE, specifically, a brief description of the BEPLATE system including hardware and software requirements, a description of the complete simulation process, discussion of rules for generating models, and additional reference material. This system of codes consists of model generators (PIGS or PATRAN), input processor (BEPIN), the simulation code (BEPLATE) and postprocessing codes (PATRAN or CONPLOT).

  12. An Introduction to Plate Tectonics

    NSDL National Science Digital Library

    This page is a brief introduction to plate tectonics. It starts with a discussion of the evolution of the theory of plate tectonics and the arguments supporting it. It then discusses the processes associated with tectonics and the types of plate boundaries: divergent, convergent and transform boundaries. It concludes with a discussion of the current hypotheses of what causes plates to move.

  13. Caribbean plate interactions

    SciTech Connect

    Ball, M. (Geological Survey, Denver, CO (United States))

    1993-02-01

    Vector analysis of plate motions, derived from studies of Atlantic magnetic lineations and fracture zone trends, indicates the following relative movements between the Caribbean, North American, and South American Plates. (1) During Early Jurassic to Early Cretaceous, the North American Plate moved 1900 km westward and 900 km northward relative to the South American Plate. A broad zone including the Caribbean region, i.e., the zone between the North and South America Plates, was a site of left-lateral shear and north-south extension. (2) During Early Cretaceous to Late Cretaceous, the North American Mate moved an additional 1200 km westward relative to South America across this zone. (3) During Late Cretaceous to the end of the Eocene, the North American Plate moved 200 km westward and 400 km northward relative to the South American Plate. (4) From the end of the Eocene to near the end of the Miocene, North America converged on South America some 200 km and moved 100 km eastward relative to it. Through the Mesozoic and earliest Tertiary history of the Caribbean, the region was a shear zone within which left-lateral displacement exceeded 3000 km and north-south extension exceeded 1300 km. In regard to time, 80% of the history of the Caribbean region is one of north-south extension and left-lateral shear. In terms of space, 97% of the shear is left-lateral and the ratio of divergence versus convergence is 7 to 1. Thus, characterizing the Caribbean region, and the Atlantic to its east, as a zone of north-south extension and left-lateral shear, is a fair generalization.

  14. A database of worldwide glacier thickness observations

    NASA Astrophysics Data System (ADS)

    Gärtner-Roer, I.; Naegeli, K.; Huss, M.; Knecht, T.; Machguth, H.; Zemp, M.

    2014-11-01

    One of the grand challenges in glacier research is to assess the total ice volume and its global distribution. Over the past few decades the compilation of a world glacier inventory has been well-advanced both in institutional set-up and in spatial coverage. The inventory is restricted to glacier surface observations. However, although thickness has been observed on many glaciers and ice caps around the globe, it has not yet been published in the shape of a readily available database. Here, we present a standardized database of glacier thickness observations compiled by an extensive literature review and from airborne data extracted from NASA's Operation IceBridge. This database contains ice thickness observations from roughly 1100 glaciers and ice caps including 550 glacier-wide estimates and 750,000 point observations. A comparison of these observational ice thicknesses with results from area- and slope-dependent approaches reveals large deviations both from the observations and between different estimation approaches. For glaciers and ice caps all estimation approaches show a tendency to overestimation. For glaciers the median relative absolute deviation lies around 30% when analyzing the different estimation approaches. This initial database of glacier and ice caps thickness will hopefully be further enlarged and intensively used for a better understanding of the global glacier ice volume and its distribution.

  15. Critical thickness in silicone thermosets

    E-print Network

    Deopura, Manish, 1975-

    2005-01-01

    Critical thickness effects are utilized to achieve high fracture toughness in brittle polymers. The postulate of critical thickness, which is: "Macroscopically brittle polymers deform in a ductile fashion below a critical ...

  16. Liquid film thickness measurement by two-line TDLAS

    SciTech Connect

    Yang, Huinan [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, China and IVG, University of Duisburg-Essen, 47057, Duisburg (Germany); Chen, Jun; Cai, Xiaoshu [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai (China); Greszik, Daniel; Dreier, Thomas; Schulz, Christof [IVG, University of Duisburg-Essen, 47057, Duisburg (Germany)

    2014-04-11

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ?1.4 ?m was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  17. Nonlinear vibration of thick stiff fabric with small flexural stiffness

    NASA Astrophysics Data System (ADS)

    Chen, J.-P.; Wang, S.-Z.; Wu, W.-Y.; Gu, H.-B.

    2008-02-01

    Dynamic behaviour of fabric is very complex during weaving, dyeing and finishing processes. Thick stiff fabric vibration has great influence not only on the fabric itself but also on the performance of machine. The theoretic analysis for the nonlinear free vibration of thick stiff fabric with small flexural stiffness is put forward in the paper. The nonlinear partial differential equation is derived by applying the flexible thin plate theory, and then transformed into nonlinear ordinary differential equation by the Galerkin method. The approximate analytical solution is obtained by the homotopy perturbation method.

  18. Effect of the absorption coefficient of aluminium plates on their thermoelastic bending in photoacoustic experiments

    NASA Astrophysics Data System (ADS)

    Markushev, D. D.; Ordonez-Miranda, J.; Rabasovi?, M. D.; Galovi?, S.; Todorovi?, D. M.; Bialkowski, S. E.

    2015-06-01

    The open-cell photoacoustic signal measured in the transmission configuration for aluminum thin plates with thicknesses of 280 ?m, 197 ?m, and 112 ?m is experimentally and theoretically analyzed, in the 20 Hz-7 kHz modulation frequency range. It is shown that the observed differences between the predictions of the standard thermoelastic model and the experiment data of both the amplitude and phase of the photoacoustic signal can be overcome by considering the aluminum samples coated with a thin layer of black paint as volume-absorber materials. This new approach provides a quite good agreement with the obtained experimental data, in the whole frequency range, and yields an effective absorption coefficient of (16 ± 2) mm-1, for a 280 ?m-thick sample. The introduction of the finite absorption coefficient led to the correct ratio between the thermal diffusion and thermoelastic components of the photoacoustic signal. Furthermore, it is found that the "volume-absorber" approach accurately describes the behavior of the amplitude, but not that of the phase recorded for a 112 ?m-thick sample, due to its relatively strong thermoelastic bending, which is not considered by this theory. Within the approximation of the small bending, the proposed "volume-absorber" model provides a reliable description of the photoacoustic signal for Al samples thicker than 112 ?m, and extends the applicability of the classical "opaque" approach.

  19. Cortical Thickness: Practicalities and Comparisons

    Microsoft Academic Search

    David Perlman

    2007-01-01

    In Part I, some practical aspects of cortical thickness analysis are examined, using the software package Freesurfer. Repeatability of surface measurements and intra-subject surface alignment are tested, and optimization is discussed. In Part II, the thickness measurements gen- erated by Freesurfer are compared with the thickness measurements generated by solving Laplace's Equation in the cortical ribbon.

  20. LOWLID FORMATION AND PLATE TECTONICS ON EXOPLANETS

    NASA Astrophysics Data System (ADS)

    Stamenkovic, V.; Noack, L.; Breuer, D.

    2009-12-01

    The last years of astronomical observation have opened the doors to a universe filled with extrasolar planets. Detection techniques still only offer the possibility to detect mainly Super-Earths above five Earth masses. But detection techniques do steadily improve and are offering the possibility to detect even smaller planets. The observations show that planets seem to exist in many possible sizes just as the planets and moons of our own solar system do. It is only a natural question to ask if planetary mass has an influence on some key habitability factors such as on plate tectonics, allowing us to test which exoplanets might be more likely habitable than others, and allowing us to understand if plate tectonics on Earth is a stable or a critical, instable process that could easily be perturbed. Here we present results derived from 1D parameterized thermal evolution and 2D/3D computer models, showing how planetary mass influences the propensity of plate tectonics for planets with masses ranging from 0.1 to 10 Earth masses. Lately [2, 3] studied the effect of planetary mass on the ability to break plates and hence initiate plate tectonics - but both derived results contradictory to the other. We think that one of the reasons why both studies [2, 3] are not acceptable in their current form is partly due to an oversimplification. Both treated viscosity only temperature-dependent but neglected the effect pressure has on enlarging the viscosity in the deep mantle. More massive planets have therefore a stronger pressure-viscosity-coupling making convection at high pressures sluggish or even impossible. For planets larger than two Earth masses we observe that a conductive lid (termed low-lid) forms above the core-mantle boundary and thus reduces the effective convective part of the mantle when including a pressure-dependent term into the viscosity laws as shown in [1]. Moreover [2, 3] use time independent steady state models neglecting the fact that plate tectonics is a dynamic process changing with time. By combining 1D thermal time evolution models and 2D/3D steady state models we are able to conclude that planetary mass does influence the propensity of plate tectonics on planets. The pressure dependence changes the scaling laws for parameterized models and influences the scaling of stresses associated with breaking of plates and thus the initiation of plate tectonics. The results indicate that for planets with masses larger than Earth lithospheric plates are either becoming thicker or remain similar in thickness and yield stresses to break the plates increase - making it harder to assume that plate tectonics is more likely on Super-Earths. Moreover, convective stresses decrease more than yield stresses do for planets smaller than Earth, leading to the fact that planets with masses close to one Earth mass seem to have better chances to exhibit plate tectonics than larger or smaller planets with similar composition and structure. References [1] Noack, L. Stamenkovic, V., and Breuer, D. (2009) ESLAB 09, P1.04. [2] Valencia, D., O’Connell, R.J., and Sasselov, D.D. (2007) Astroph. J., 670, 45-48. [3] O’Neill, C. and Lenardic, A. (2007) GRL, 34, L19204

  1. Thick films of X-ray polycrystalline mercuric iodide detectors

    NASA Astrophysics Data System (ADS)

    Schieber, M.; Hermon, H.; Zuck, A.; Vilensky, A.; Melekhov, L.; Shatunovsky, R.; Meerson, E.; Saado, Y.; Lukach, M.; Pinkhasy, E.; Ready, S. E.; Street, R. A.

    2001-05-01

    Polycrystalline HgI2 thick film detectors are among the leading semiconductor materials to be used as direct converters in X-ray digital radiography. Their properties along with a survey of the properties of alternative materials, such as PbI2 or A-Se, will be given. The preparation of HgI2 detector plates, both by direct evaporation (Physical vapor deposition, (PVD)) and by binding the individual crystallites with polymeric glue, forming screen-printed (SP) detector plates, will be described. The microstructure of the PVD thick films showing a columnar morphology, as determined by SEM measurements, will be shown. The X-ray response to radiological X-ray generator of 85 kVp using the current integration mode will be reported for both PVD and SP films. Finally, some X-ray images taken at Xerox-Parc using HgI2 polycrystalline detectors will be shown.

  2. Plate-mantle coupling from post-Pangea plate kinematics

    NASA Astrophysics Data System (ADS)

    Zahirovic, Sabin; Dietmar Müller, R.; Seton, Maria; Flament, Nicolas

    2015-04-01

    Convection in the Earth's mantle that involves plates at the surfaces gives rise to plate velocities that vary through time and depend on the balance of plate boundary forces, with the present-day providing a snapshot of this ongoing process. However, present-day plate velocities do not capture plate behaviour over geologically representative timeframes and thus cannot be used to evaluate factors limiting plate velocities. Previous studies investigated the effects of continental keels on plate speeds by either using the present-day snapshot or a limited number of reconstructed plate configurations, often leading to conflicting results. For example, an early assumption was that continental keels (especially cratons) were unlikely to impede fast plate motions because India's velocity approached ~20 cm/yr in the Eocene prior to the collision with Eurasia. We employ a modern plate reconstruction approach with evolving global topological plate boundaries for the post-Pangea timeframe (since 200 Ma) to evaluate factors controlling plate velocities. Plate boundary configurations and plate velocities are extracted from the open-source and cross-platform plate reconstruction package GPlates (www.gplates.org) at 1 Myr intervals. For each plate, at each timestep, the area of continental and cratonic lithosphere is calculated to evaluate the effect on plate velocities. Our results support that oceanic plates tend to be 2-3 times faster than plates with large portion of continental plate area, consistent with predictions of numerical models of mantle convection. The fastest plates (~8.5 cm/yr RMS) are dominated by oceanic plate area and high subducting portion of plate perimeter, while the slowest plates (~2.6-2.8 cm/yr RMS) are dominated by continental plate area and bounded by transforms and mid-oceanic ridge segments. Importantly, increasing cratonic fractions (both Proterozoic and Archean lithosphere) significantly impede plate velocities, suggesting that deep continental keels impinge on asthenospheric flow to increase shear traction, thus anchoring the plate in the more viscous mantle transition zone. However, plates with significant cratonic fragments exhibit short-lived (~10 Myr) accelerations, such as the rapid motion of the Indian plate that is correlated with plume head arrivals as recorded by large igneous province (LIPs) emplacement, highlighting the necessity to analyse plate velocities over long geological timeframes. By evaluating factors controlling plate velocities in the post-Pangea timeframe, simple principles can be applied to highlight potential plate velocity artefacts for Paleozoic and earlier times for which no hotspot tracks, nor in-situ seafloor spreading histories, are preserved. Based on the post-Pangea timeframe, a principle that can be applied to pre-Pangea times is that plates with less than ~50% continental area can reach RMS velocities of ~20 cm/yr, while plates with more than 50% continental fraction do not exceed RMS velocities of ~10 cm/yr. Similarly, plates with large portions of continental or cratonic area with RMS velocities exceeding ~15 cm/yr for more than ~10 Myr should be flagged as potential artefacts requiring further justification of plate driving forces in such scenarios.

  3. Present-day intra-plate deformation of the Eurasian plate

    NASA Astrophysics Data System (ADS)

    Garcia-Sancho, Candela; Govers, Rob; Warners-Ruckstuhl, Karin N.; Tesauro, Magdala

    2014-05-01

    We build on the results of two recent, yet independent, studies. In the first (Warners-Ruckstuhl et al., 2013) the forces on, and stresses within the Eurasian plate were established. In the second (Tesauro et al., 2012) the distribution of mechanically strong and weak parts of the Eurasian plate was found. The aim of our work is to predict lithospheric deformation of the Eurasian plate and to compare it with observations. This constitutes a test of both the force/stress results and of the strength results. Specific questions are to which extent stresses localize in specific regions and whether micro-plates as identified by geodesists arise naturally from the results. Importantly, Warners-Ruckstuhl et al. (2013) found an ensemble of mechanically consistent force models based on plate interaction forces, lithospheric body forces and convective tractions. Each of these force sets is in mechanical equilibrium. A subset drives Eurasia in the observed direction of absolute motion and generates a stress field in a homogeneous elastic plate that fits observed horizontal stress directions to first order. Deformation models constitute a further test and a possibility to discriminate between the remaining force sets. Following Tesauro et al. (2012) we assume five different compositions for the upper and lower crust. We use their geotherms and crustal thickness maps to estimate vertical distributions of strength at any location within the Eurasian plate. Based on the assumption that horizontal strain rates do not vary with depth allows us to estimate the vertically averaged viscosity of each point. We include major active faults in our mechanical model. We compare our results with GPS velocities, InSAR, seismic, and paleomagnetic observations, which capture present-day and long-term deformation. We discuss various causes for differences.

  4. Design of broadband transmission quarter-wave plates for polarization control of isolated attosecond pulses

    NASA Astrophysics Data System (ADS)

    Chen, Shujing; Lin, Chengyou; Gao, Hua

    2015-07-01

    Using a standard Levenberg–Marquardt algorithm, broadband quarter-wave plates (QWPs) with bandwidth from 3 to 18 eV in the extreme ultraviolet (EUV) region were designed using aperiodic Mo/Si multilayers. By analyzing the design results of the Mo/Si multiayers with different bilayer numbers, we found that a Mo/Si multilayer with more bilayers can achieve broader phase control, but suffers from lower total throughput and a degree of circular polarization. In addition, the pulse broadenings caused by the group delay dispersions of the designed broadband QWPs were studied, and their layer distributions were investigated. The oscillating distribution of bilayer thickness in optimized multilayers was observed, which is considered to be the reason for forming the broadband phase control. Such broadband QWPs can be applied to generate a circularly polarized broadband EUV source, such as isolated attosecond pulse, directly from a linearly polarized source.

  5. Perforation of the Third Extensor Compartment by the Drill Bit During Palmar Plating of the Distal Radius

    Microsoft Academic Search

    W. PICHLER; W. GRECHENIG; H. CLEMENT; G. WINDISCH; N. P. TESCH

    2009-01-01

    The frequency of penetration into the third extensor compartment when drilling the distal screw holes was assessed for four different palmar distal radius plates in 160 cadaver forearms. Penetration into this compartment occurred in 43%. Different plates had different penetration rates: 3.5 LCP four-hole locking T-plate: 20%, 3.5 LCP three-hole locking plate: 42.5%, 2.4 palmar LCP standard plate and the

  6. The magma ocean as an impediment to lunar plate tectonics

    NASA Technical Reports Server (NTRS)

    Warren, Paul H.

    1993-01-01

    The primary impediment to plate tectonics on the moon was probably the great thickness of its crust and particularly its high crust/lithosphere thickness ratio. This in turn can be attributed to the preponderance of low-density feldspar over all other Al-compatible phases in the lunar interior. During the magma ocean epoch, the moon's crust/lithosphere thickness ratio was at the maximum theoretical value, approximately 1, and it remained high for a long time afterwards. A few large regions of thin crust were produced by basin-scale cratering approximately contemporaneous with the demise of the magma ocean. However, these regions probably also tend to have uncommonly thin lithosphere, since they were directly heated and indirectly enriched in K, Th, and U by the same cratering process. Thus, plate tectonics on the moon in the form of systematic lithosphere subduction was impeded by the magma ocean.

  7. THERMAL BUCKLING OF THICK ANTISYMMETRIC ANGLE-PLY LAMINATES

    Microsoft Academic Search

    T. R. Tauchert

    1987-01-01

    The buckling behavior of moderately thick antisymmetric angle-ply laminates that are simply supported and subject to a uniform temperature rise is analyzed. Transverse shear deformation is accounted for by employing the thermoelastic version of the Reissner-Mindlin theory. Results for the classical thin-plate theory are obtained as a special case. Numerical results are presented for fiber-reinforced laminates and show the effects

  8. Fe-Pt thick-film magnets prepared by electroplating method

    NASA Astrophysics Data System (ADS)

    Yanai, T.; Furutani, K.; Ohgai, T.; Nakano, M.; Suzuki, K.; Fukunaga, H.

    2015-05-01

    Fe-Pt thick-films were electroplated on Ta substrates using a direct current, and the magnetic properties of the film were evaluated. The Fe-Pt films with the thickness from 3 to 23 ?m were obtained by changing in the plating time from 2 to 20 min. As the as-plated Fe-Pt films had the disordered fcc (face-centered-cubic) structure and low coercivity (<5 kA/m), we annealed the films at 700 °C for 60 min. The annealing induced the phase transformation from fcc structure to fct (face-centered-tetragonal) one, and we consequently obtained the Fe50Pt50 thick-films with large coercivity of approximately 700 kA/m. The large coercivity was observed in the wide thickness range for our experimental conditions. Therefore, we concluded that our prepared Fe-Pt film is one of the attractive thick-film magnets.

  9. Chemical and structural analyses of titanium plates retrieved from patients.

    PubMed

    Pinto, C M S A; Asprino, L; de Moraes, M

    2015-08-01

    The aim of this study was to evaluate the microscopic structure and chemical composition of titanium bone plates and screws retrieved from patients with a clinical indication and to relate the results to the clinical conditions associated with the removal of these devices. Osteosynthesis plates and screws retrieved from 30 patients between January 2010 and September 2013 were studied by metallographic, gas, and energy dispersive X-ray (EDX) analyses and the medical records of these patients were reviewed. Forty-eight plates and 238 screws were retrieved. The time elapsed between plate and screw insertion and removal ranged between 11 days and 10 years. Metallographic analysis revealed that all the plates were manufactured from commercially pure titanium (CP-Ti). The screw samples analyzed consisted of Ti-6Al-4V alloy, except four samples, which consisted of CP-Ti. Titanium plates studied by EDX analysis presented greater than 99.7% titanium by mass. On gas analysis of Ti-6Al-4V screws, three samples were outside the standard values. One CP-Ti screw sample and one plate sample also presented an oxygen analysis value above the standard. The results indicated that the physical properties and chemical compositions of the plates and screws did not correspond with the need to remove these devices or the time of retention. PMID:25735535

  10. Discovering Plate Boundaries

    NSDL National Science Digital Library

    Rice University's Earth Science Department offers the Discovering Plate Boundaries educational activity. The exercise is described as a "data rich exercise to help students discover the processes that occur at plate tectonic boundaries" and has been used successfully with 5th graders to undergraduates. The site provides the necessary downloads of maps; earthquake, volcanic, seafloor, topographic, and bathymetric data; and teacher guides and complete instructions. Because the activity can be geared towards such a large range of students, is well designed, and is easily accessible, educators will definitely appreciate the site.

  11. Plating under reduced pressure

    SciTech Connect

    Dini, J.W.; Beat, T.G.; Cowden, W.C. [Lawrence Livermore National Lab., CA (United States); Ryan, L.E.; Hewitt, W.B. [TRW, Inc., Redondo Beach, CA (United States)

    1992-06-01

    Plating under reduced pressure was evaluated for both electroless nickel and electrodeposited copper systems. The objective was to reduce pitting of these coatings thereby further enhancing their usage for diamond turning applications. Cursory experiments with electroless nickel showed reduced porosity when deposition was done at around 500 torr. Detailed experiments with electrodeposited copper at around 100 torr provided similar results. Scanning tunneling microscopy was effectively used to show the improvement in the copper deposits plated under reduced pressure. Benefits included reduced surface roughness and finer and denser grain structure.

  12. Reduced Plating Ignitron

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A (Inventor); Pearson, J Boise (Inventor)

    2014-01-01

    An ignitron apparatus has an airtight tubular housing having a first sealed end and a second sealed end. An anode is connected at the first sealed end, projecting into the housing, and a recess at the second sealed and forms a well which contains a quantity of liquid gallium or gallium alloy making up the cathode. An ignitor projects through the liquid metal and into the housing. The inner surface of the housing includes at least one plating-reduction structure to prevent electrical shorting of the apparatus caused by plating of the liquid metal.

  13. Volcanoes, Plates, and Chains

    NSDL National Science Digital Library

    In this lesson students will discover how seamounts in the Axial-Cobb-Eikelberg-Patton chain were formed. They will learn about the processes that form seamounts, describe the movement of tectonic plates in the Gulf of Alaska region and explain the types of volcanic activity that might be associated with these movements, and describe how a combination of hotspot activity and tectonic plate movement could produce the arrangement of seamounts observed in this chain. This hands-on activity uses online data resources and includes: focus questions, learning objectives, teaching time, audio/visual materials needed, background information, learning procedures, evaluations, extensions, as well as resources and student handouts.

  14. Tectonic Plate Motion

    NSDL National Science Digital Library

    The representation shows the direction of motion of the Earth's major plates as measured through NASA's satellite laser ranging (SLR) technology. A series of world maps, accompanying text, and the subsequent links explain this technology in great detail. One can click on the Index Map for Satellite Laser Ranging site Velocity and see the vectors (arrows) that indicate the direction and rate of movement of Earth's plates in much more detail. Accompanying text gives a more detailed explanation of what each sub map is showing.

  15. Plate Tectonics and Volcanism

    NSDL National Science Digital Library

    This is a lesson where learners explore plate movement and the relationship between plate tectonics and volcanoes. The lesson models scientific inquiry using the 5E instructional model and includes teacher notes, prerequisite concepts, common misconceptions, student journal and reading. This is lesson five in the Astro-Venture Geology Training Unit that was developed to increase students' awareness of and interest in astrobiology and the many career opportunities that utilize science, math and technology skills. The lessons are designed for educators to use with the Astro-Venture multimedia modules.

  16. Predicting gravity and sediment thickness in Afghanistan

    NASA Astrophysics Data System (ADS)

    Jung, W.; Brozena, J.; Peters, M.

    2013-02-01

    The US Naval Research Laboratory conducted comprehensive high-altitude (7 km above mean sea level) aero-geophysical surveys over Afghanistan in 2006 (Rampant Lion I). The surveys were done in collaboration with the US Geological Survey and upon the request of Islamic Republic of Afghanistan Ministry of Mines. In this study, we show that a best fitting admittance between topography and airborne gravity in western Afghanistan can be used to predict airborne gravity for the no-data area of eastern Afghanistan where the mountains are too high to conduct airborne surveys, due to the threat of ground fire. The differences between the airborne and the predicted gravity along a tie-track through the no-data area were found to be within ±12 mGal range with rms difference 7.3 mGal, while those between the predicted gravity from a simple Airy model (with compensation depth of 32 km and crustal density of 2.67 g cm-3) and the airborne gravity were within ±22 mGal range with rms difference 10.3 mGal. A combined airborne free-air anomaly has been constructed by merging the predicted gravity with the airborne data. We also demonstrate that sediment thickness can be estimated for basin areas where surface topography and airborne free-air anomaly profiles do not show a correlation presumably because of thick sediments. In order to estimate sediment thickness, we first determine a simple linear relationship from a scatter plot of the airborne gravity points and the interpolated Shuttle Radar Topography Mission (SRTM) topography along the Rampant Lion I tracks, and computed corresponding quasi-topography tracks by multiplying the linear relationship with the airborne free-air anomalies. We then take the differences between the SRTM and quasi-topography as a first-order estimate of sediment thickness. A global gravity model (GOCO02S), upward continued to the same altitude (7 km above mean sea level) as the data collection, was compared with the low-pass filtered (with cutoff wavelength 132 km which is approximately equivalent to the reported safe degree and order 250 of GOCO02S at 34º N) combined airborne free-air anomalies. The rms difference between the two data sets was 12.4 mGal. The observed admittance in the western Afghanistan mountains appears to be best fit to a theoretical elastic plate compensation model (with an effective elastic thickness of 5 km and crustal thickness of 22 km) where the ratio between surface load and subsurface load is equal.

  17. ILC TARGET WHEEL RIM FRAGMENT/GUARD PLATE IMPACT ANALYSIS

    SciTech Connect

    Hagler, L

    2008-07-17

    A positron source component is needed for the International Linear Collider Project. The leading design concept for this source is a rotating titanium alloy wheel whose spokes rotate through an intense localized magnetic field. The system is composed of an electric motor, flexible motor/drive-shaft coupling, stainless steel drive-shaft, two Plumber's Block tapered roller bearings, a titanium alloy target wheel, and electromagnet. Surrounding the target wheel and magnet is a steel frame with steel guarding plates intended to contain shrapnel in case of catastrophic wheel failure. Figure 1 is a layout of this system (guard plates not shown for clarity). This report documents the FEA analyses that were performed at LLNL to help determine, on a preliminary basis, the required guard plate thickness for three potential plate steels.

  18. Time domain scattering and radar cross section calculations for a thin, coated perfectly conducting plate

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Beggs, John H.

    1991-01-01

    Radar cross section (RCS) calculations for flat, perfectly conducting plates are readily available through the use of conventional frequency domain techniques such as the Method of Moments (MOM). However, if the plate is covered with a dielectric material that is relatively thick in comparison with the wavelength in the material, these frequency domain techniques become increasingly difficult to apply. The application is presented of the Finite Difference Time Domain (FDTD) technique to the problem of electromagnetic scattering and RCS calculations from a thin, perfectly conducting plate that is coated with a thick layer of lossless dielectric material. Both time domain and RCS calculations are presented and discussed.

  19. Time domain scattering and radar cross section calculations for a thin, coated perfectly conducting plate

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Beggs, John H.

    1991-01-01

    Radar cross section (RCS) calculations for flat, perfectly conducting plates are readily available through the use of conventional frequency domain techniques such as the Method of Moments (MOM). However, if the plate is covered with a dielectric material that is relatively thick in comparison with the wavelength in the material, these frequency domain techniques become increasingly difficult to apply. We present the application of the Finite Difference Time Domain (FDTD) Technique to the problem of electromagnetic scattering and RCS calculations from a thin, perfectly conducting plate that is coated with a thick layer of lossless dielectric material. Both time domain and RCS calculations are presented and disclosed.

  20. Integrated high-temperature piezoelectric plate acoustic wave transducers using mode conversion

    Microsoft Academic Search

    Kuo-ting Wu; Makiko Kobayashi; Cheng-kuei Jen

    2009-01-01

    Piezoelectric thick (>66 mum) films have been directly coated onto aluminum (Al) substrates using a sol-gel spray technique. With top electrode, these films serve as integrated ultrasonic transducers (IUT), which normally operate as thickness longitudinal wave transducers. When such IUT are located at the edges of the metallic plates, they can excite and detect symmetrical, antisymmetric and shear horizontal types

  1. Stacking-sequence optimization for buckling of laminated plates by integer programming

    Microsoft Academic Search

    Raphael T. Haftka; Joanne L. Walsht

    1992-01-01

    Integer-programming formulations for the design of symmetric and balanced laminated plates under biaxial compression are presented. Both maximization of buckling load for a given total thickness and the minimization of total thickness subject to a buckling constraint are formulated. The design variables that define the stacking sequence of the laminate are zero-one integers. It is shown that the formulation results

  2. Solidification Characteristics Modeling of Phase Change Material in Plate Capsule of Cool Storage System

    Microsoft Academic Search

    Guiyin Fang; Zhi Chen

    2011-01-01

    The analytical solutions to solidification characteristics of a phase change material in the plate capsule of a cool storage system are presented. The influence of the Stefan number (the ratio of sensible heat to latent heat of a cool storage material) on phase change solidification thickness and temperature distribution in the solid region is analyzed. The phase change solidification thickness

  3. Accurate Simulation of Acoustic Emission Sources in Composite Plates

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Gorman, M. R.

    1994-01-01

    Acoustic emission (AE) signals propagate as the extensional and flexural plate modes in thin composite plates and plate-like geometries such as shells, pipes, and tubes. The relative amplitude of the two modes depends on the directionality of the source motion. For source motions with large out-of-plane components such as delaminations or particle impact, the flexural or bending plate mode dominates the AE signal with only a small extensional mode detected. A signal from such a source is well simulated with the standard pencil lead break (Hsu-Neilsen source) on the surface of the plate. For other sources such as matrix cracking or fiber breakage in which the source motion is primarily in-plane, the resulting AE signal has a large extensional mode component with little or no flexural mode observed. Signals from these type sources can also be simulated with pencil lead breaks. However, the lead must be fractured on the edge of the plate to generate an in-plane source motion rather than on the surface of the plate. In many applications such as testing of pressure vessels and piping or aircraft structures, a free edge is either not available or not in a desired location for simulation of in-plane type sources. In this research, a method was developed which allows the simulation of AE signals with a predominant extensional mode component in composite plates requiring access to only the surface of the plate.

  4. A new multilength scale plate theory with delamination

    SciTech Connect

    Williams, T.O.

    1997-11-01

    Laminated composite plates and shells are potential candidates for many demanding structural applications. A natural choice of analytical/numerical model for the analysis of such structures are equivalent two-dimensional (2D) plate and shell theories. These types of theories provide an efficient and potentially accurate alternative to the use of a three-dimensional finite element (FE) analysis. To effectively model the behavior of composite structures a plate theory must be able to accurately model a variety of inherent history-dependent phenomena. These phenomena include plasticity, viscoplasticity, viscoelasticity, constituent damage within lamina, delamination, and local (sublaminate) and global buckling of the plate. Delamination and local buckling operate at length scales on the order of the lamina thickness. The global buckling and overall motion of a plate can be associated with dimensions of the order of the laminate thickness. A new type of laminated plate theory is presented. It is based on a generalized displacement framework obtained from a superposition of global and local displacement fields. The functional forms of the global and local displacements are arbitrary. The theory represents a novel two length scale or local-global approach to plate analysis. The theory incorporates delamination and/or nonlinear elastic or inelastic interfacial behavior in a unified fashion through the use of interfacial constitutive relations. The theory accounts for nonlinearities in the von Karman sense to allow for the analysis of buckling behavior. Thus, the theory represents a general framework for obtaining any order and type of displacement based plate theory in the presence of delamination, buckling, and/or nonlinear material behavior as well as the interactions between these effects.

  5. Highly conductive, multi-layer composite precursor composition to fuel cell flow field plate or bipolar plate

    DOEpatents

    Jang, Bor Z. (Centerville, OH); Zhamu, Aruna (Centerville, OH); Guo, Jiusheng (Centerville, OH)

    2011-02-15

    This invention provides a moldable, multiple-layer composite composition, which is a precursor to an electrically conductive composite flow field plate or bipolar plate. In one preferred embodiment, the composition comprises a plurality of conductive sheets and a plurality of mixture layers of a curable resin and conductive fillers, wherein (A) each conductive sheet is attached to at least one resin-filler mixture layer; (B) at least one of the conductive sheets comprises flexible graphite; and (C) at least one resin-filler mixture layer comprises a thermosetting resin and conductive fillers with the fillers being present in a sufficient quantity to render the resulting flow field plate or bipolar plate electrically conductive with a conductivity no less than 100 S/cm and thickness-direction areal conductivity no less than 200 S/cm.sup.2.

  6. Plate Tectonics: Lines of Evidence

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2006-11-01

    This Science Object is the fifth of five Science Objects in the Plate Tectonics SciPack. It explores the physical, geographical, and geological evidence for the theory of continental drift and plate tectonics. Plate tectonics provide a unifying framework for understanding Earth processes and history, and is supported by many lines of evidence. Over geologic time, plates move across the globe creating different continents (and positions of continents). Learning Outcomes:? Use plate tectonics to explain changes in continents and their positions over geologic time.? Provide evidence for the idea of plates, including the location of earthquakes and volcanoes, continental drift, magnetic orientation of rocks in the ocean floor, etc.

  7. Laser ultrasonic inspection of plates using zero-group velocity lamb modes.

    PubMed

    Clorennec, Dominique; Prada, Claire; Royer, Daniel

    2010-05-01

    A noncontact laser-based ultrasonic technique is proposed for detecting small plate thickness variations caused by corrosion and adhesive disbond between two plates. The method exploits the resonance at the minimum frequency of the S(1) Lamb mode dispersion curve. At this minimum frequency, the group velocity vanishes, whereas the phase velocity remains finite. The energy deposited by the laser pulse generates a local resonance of the plate. This vibration is detected at the same point by an optical interferometer. First experiments show the ability to image a 1.5-microm deep corroded area on the back side of a 0.5-mm-thick duralumin plate. Because of the finite wavelength of the S(1)- zero group velocity (ZGV) mode, the spatial resolution is limited to approximately twice the plate thickness. With the same technique we investigate the state of adhesive bonds between duralumin and glass plates. The S(1)-Lamb mode resonance is strongly attenuated when plates are rigidly bonded. In the case of thin adhesive layers, we observed other resonances, associated with ZGV modes of the multi-layer structure, whose frequencies and amplitudes vary with adhesive thickness. Experiments were carried out on real automotive adhesively bonded structures and the results were compared with images obtained by X-ray radiography. PMID:20442022

  8. University Center Plated Entrees

    E-print Network

    Lee, Herbie

    , artichokes and herbs served with Crushed Yukon Golds and lemon-caper buerre blanc Pacific Salmon Florentine en Croute $23.95 Salmon filet and lemon creamed spinach wrapped in flaky puff pastry served with lemon-pecan Basmati pilaf and sauce Béarnaise #12;University Center Plated Entrees Poultry Moroccan

  9. Plate Tectonics Quiz

    NSDL National Science Digital Library

    This quiz for younger students asks them 10 questions about plate motions, rock types in continental and oceanic crust, crustal formation and mountain building, the supercontinent Pangea, and the theory of continental drift. A link to a page on continental drift provides information to answer the questions.

  10. Plate Tectonic Movement Visualizations

    NSDL National Science Digital Library

    This collection provides a wide array of visual resources and supporting material about plate tectonic movements. Visualizations include simple animations, GIS-based animated maps, paleogeographic maps and globes, and numerous illustrations and photos. This collection is not exhaustive but does represent some of the best sources for teaching. Resources can be incorporated into lectures, labs, or other activities.

  11. The Plate Tectonics Project

    ERIC Educational Resources Information Center

    Hein, Annamae J.

    2011-01-01

    The Plate Tectonics Project is a multiday, inquiry-based unit that facilitates students as self-motivated learners. Reliable Web sites are offered to assist with lessons, and a summative rubric is used to facilitate the holistic nature of the project. After each topic (parts of the Earth, continental drift, etc.) is covered, the students will…

  12. Perforated plates for cryogenic regenerators and method of fabrication

    DOEpatents

    Hendricks, John B. (Huntsville, AL)

    1994-01-01

    Perforated plates (10) having very small holes (14) with a uniform diameter throughout the plate thickness are prepared by a "wire drawing" process in which a billet of sacrificial metal is disposed in an extrusion can of the plate metal, and the can is extruded and restacked repeatedly, converting the billet to a wire of the desired hole diameter. At final size, the rod is then sliced into wafers, and the wires are removed by selective etching. This process is useful for plate metals of interest for high performance regenerator applications, in particular, copper, niobium, molybdenum, erbium, and other rare earth metals. Er.sub.3 Ni, which has uniquely favorable thermophysical properties for such applications, may be incorporated in regions of the plates by providing extrusion cans (20) containing erbium and nickel metals in a stacked array (53) with extrusion cans of the plate metal, which may be copper. The array is heated to convert the erbium and nickel metals to Er.sub.3 Ni. Perforated plates having two sizes of perforations (38, 42), one of which is small enough for storage of helium, are also disclosed.

  13. Perforated plates for cryogenic regenerators and method of fabrication

    DOEpatents

    Hendricks, J.B.

    1994-03-29

    Perforated plates having very small holes with a uniform diameter throughout the plate thickness are prepared by a [open quotes]wire drawing[close quotes] process in which a billet of sacrificial metal is disposed in an extrusion can of the plate metal, and the can is extruded and restacked repeatedly, converting the billet to a wire of the desired hole diameter. At final size, the rod is then sliced into wafers, and the wires are removed by selective etching. This process is useful for plate metals of interest for high performance regenerator applications, in particular, copper, niobium, molybdenum, erbium, and other rare earth metals. Er[sub 3]Ni, which has uniquely favorable thermophysical properties for such applications, may be incorporated in regions of the plates by providing extrusion cans containing erbium and nickel metals in a stacked array with extrusion cans of the plate metal, which may be copper. The array is heated to convert the erbium and nickel metals to Er[sub 3]Ni. Perforated plates having two sizes of perforations, one of which is small enough for storage of helium, are also disclosed. 10 figures.

  14. The Influence of Pre-existing Deformation on GMA Welding Distortion in Thin Steel Plates

    NASA Astrophysics Data System (ADS)

    Davies, C. M.; Ahn, J.; Tsunori, M.; Dye, D.; Nikbin, K. M.

    2015-01-01

    Weld distortion is particularly problematic for large thin structures that are used in the assembly of ships. The drive toward lighter ships and thinner plate is restricted by the significant increase in distortion as the plate thickness decreases. The influence of pre-existing deformation in the plates to be joined on the resultant distortion in gas metal arc welded structure has been studied. DH-36 steel plate surface profiles were measured before and after the butt welding of two plates 1000 × 500 × 4 mm in size. Three dimensional finite element models that incorporate the initial plate profile have been created to simulate the welding process and to examine the relationship between the final welded plate profiles and the initial deformation present in the plates. Both symmetric and asymmetric models were considered. A significant variation in the unwelded base plates' initial distortion was observed. Generally, it has been found that if an out-of-plane deformation exists in a plate prior to welding, the level of distortion further increases in the same direction following welding. The final distortions are strongly related to the initial plate profiles. The residual stress distributions in the plates are also to some extent affected by the level of distortion initially present.

  15. HETEROTROPHIC PLATE COUNT (HPC) METHODOLOGY IN THE UNITED STATES

    EPA Science Inventory

    ABSTRACT In the United States (U.S.), the history of bacterial plate counting methods used for water can be traced largely through Standard Methods for the Examination of Water and Wastewater (Standard Methods). The bacterial count method has evolved from the original St...

  16. Interpolating Mean Rainfall Using Thin Plate Smoothing Splines

    Microsoft Academic Search

    M. F. Hutchinson

    1995-01-01

    Thin plate smoothing splines provide accurate, operationally straightforward and computationally efficient solutions to the problem of the spatial interpolation of annual mean rainfall for a standard period from point data which contains many short period rainfall means. The analyses depend on developing a statistical model of the spatial variation of the observed rainfall means, considered as noisy estimates of standard

  17. Plate mode velocities in graphite\\/epoxy plates

    Microsoft Academic Search

    W. H. Prosser; M. R. Gorman

    1994-01-01

    Measurements of the velocities of the extensional and flexural plate modes were made along three directions of propagation in four graphite\\/ epoxy composite plates. The acoustic signals were generated by simulated acoustic emission events (pencil lead breaks or Hsu-Neilsen sources) and detected by broad band ultrasonic transducers. The first arrival of the extensional plate mode, which is nondispersive at low

  18. Plate Puzzle Page 1 of 20 Plate Puzzle 1

    E-print Network

    Benitez-Nelson, Claudia

    plotting activities. Good follow-up activities are: plate tectonics flip book, epicenter plotting using tectonics. The map is an attractive display of plate tectonic features such earthquake epicenters boundaries so that one can examine the relationship of the tectonic features to the plate boundaries. The map

  19. Flexural Thickness Variations of the Maracaibo Block

    NASA Astrophysics Data System (ADS)

    Arnaiz-Rodriguez, M. S.; Audemard, F. A.

    2013-05-01

    We estimated the lateral variations of the flexural thickness (Te) of the Maracaibo Block (MB) and its adjacent terranes using a 3D numerical approach. The calculation is based on solving the fourth-order partial differential equation that governs the bending of a thin plate fixed on its boundaries (zero displacement) and variable thickness (Te), using centered finite differences. The initial mechanical model accounts for: (1) four main loads: Mérida Andes (MA), Perijá Range (PR), Santa Marta Mountains (SMM) and the Northern Colombian Andes (NCA) represented as a downs-sampled topographic grid (used as initial loads); (2) mechanical parameters extracted from previous research; (3) constant Te (25 km). Loads and Te were modified to fit the general basement configuration, and the residual topography to fit the down-sampled topography. The final result is a Te map that covers the MB and the surrounding sections of the South American Plate (SA). This map shows that the Te ranges from 30 km to 18 km, with a mean value of 23.57 km and a mode of 26 km. The orientation of the Te contours is roughly N45E, similar to the MA. The largest Te values are associated with the location of the SMM and with the deformed Guyana Shield to the southeast (Barinas Apure Basin), while the smallest ones to the MA-Maracaibo Basin flexural system. Te limit between SA and MB appears in the northern flank of the MA and the Boconó Fault, which is congruent with the gravimetric data of the area, where the Bouguer Anomaly low (that characterizes an locally compensated mountain ranged) is displaced to the north. The basement configuration within the Maracaibo Basin seems to be controlled by 2 important loads: (1) MA large load that generates the depocenter of the basin (at least 9 km); (2) PR and NCA limit the existence and outcrop of a large forebulge within the MB. Larger Te values in the north, particularly near SMM would explained why this mountain does not have sings of been isostatically compensated (as free air anomaly and Bouguer anomaly are positive). This could be related to the convergence of SA and the Caribbean Plate (CP) and the coupling related to this process. We conclude that the flexural history of the MB and the formation of the foreland basins were controlled by the lateral variations of the Te, originally generated by early crust thinning and graben formation, and by the unique distribution of loads. We also conclude that the isostatic state of the northern limit of the MB is related to large Te in SMM somehow associated to its geological and thermal history.

  20. International Thermonuclear Experimental Reactor (ITER) divertor plate performance and lifetime considerations

    SciTech Connect

    Mattas, R.F.

    1990-03-01

    The ITER divertor plate performance during the technology phase of operation has been analyzed. High-Z materials, such as tungsten and tantalum, have been considered as plasma side materials, and refractory metal alloys, Ta-10W, TZM, Nb-1Zr, and V-15Cr-5Ti, plus copper alloys have been considered as the structural materials. The fatigue lifetime have been predicted for structural plates and for duplex plates with the plasma side material bonded to the structure. The results indicate that refractory alloys have a comparable or improved performance to copper alloys. Peak allowable heat fluxes for these analyses are in the range of 15--20 MW/m{sup 2} for 2 mm thick structural plates and 7--11 MW/m{sup 2} for 4 mm thick duplex plates. 4 refs., 55 figs., 6 tabs.

  1. Renewable liquid reflecting zone plate

    SciTech Connect

    Toor, Arthur; Ryutov, Dmitri D.

    2003-12-09

    A renewable liquid reflecting zone plate. Electrodes are operatively connected to a dielectric liquid in a circular or other arrangement to produce a reflecting zone plate. A system for renewing the liquid uses a penetrable substrate.

  2. ChooseMyPlate.gov

    MedlinePLUS

    ... foods and 900 physical activities. NEW : High school lesson plans. MyPlate Kids' Place A brand new resource ... MyPlate Videos Healthy Eating on a Budget SuperTracker Lesson Plans 10 Tips Nutrition Education Series Recipes, Cookbooks, ...

  3. Tectonic Plates, Earthquakes, and Volcanoes

    NSDL National Science Digital Library

    The representation shows earthquake and volcanic activity corresponds to plate boundaries. This interactive topographical map with the ocean water removed shows the boundaries of major plates and the locations of major volcanic eruptions and earthquakes worldwide.

  4. Microwave characteristics of low density hollow glass microspheres plated with Ni thin-film

    NASA Astrophysics Data System (ADS)

    Liu, Z. W.; Phua, L. X.; Liu, Y.; Ong, C. K.

    2006-11-01

    Hollow glass microspheres coated with thin Ni films of various thicknesses (about 50-250nm) were obtained by electroless plating technique. The resultant magnetic microspheres had very low densities (˜0.39-1.28gcm-3) and low coercivities (<40Oe). As-plated films comprised of nanocrystallites embedded in amorphous matrix and postannealing treatment led to a submicrocrystalline structure and an increased saturation magnetization. The high frequency properties of the composites consisting of Ni-plated microspheres and polymer were investigated. The permittivity and permeability increased with increasing microsphere content in the composite and increasing Ni film thickness. These composites had ferromagnetic resonance peak in the range of 5-12GHz. Postannealing also had an effect on the microwave properties. The reflection loss of the composite was found dependent on the absorber material thickness, polymer:microsphere ratios, the Ni film thickness, as well as the heat treatment of the microspheres.

  5. Convection with Mobile Plates: Testing Plate Formulations with Complex, Time-Dependent Fluid Systems

    NASA Astrophysics Data System (ADS)

    Koglin, D. E.; King, S. D.

    2004-05-01

    Lowman et al. (2001) presented results of 2D convection with mobile plates where the plate velocities reverse due to the evolution of the flow in the fluid beneath them. Lowman et al. used a force balance method to implement mobile plates and we reproduce their results using a 'weak zone' based rheological plate method. For the unit aspect ratio domain with a stiff plate with a thickness of 0.05d, where d is the depth of the domain, we find linear relationships between the surface velocity and size of the weak zones and the surface heat flux and the size of the weak zones. To match the results of Lowman et al. requires square weak zones that are 0.09d in length/depth. The results are less sensitive to the viscosity contrast between the fluid and the weak zone. For the case where Lowman et al. find plate motions that reverse on a periodic time scale we also find periodic, reversing plate motions. Using a T-R periodogram (Scargle 1982; Benson et. al 2003), we find that the periods are extrememly similar, with main peaks near periods of 0.02 and 0.05 diffusion time. However, our results show an apparently more complex behavior than those of Lowman et al. (2001), as demonstrated by the difference in periodicity between the two datasets, and the amplitude modulation in our results. There are additional low-amplitude, short-period phases in our time series that are not present in the Lowman et al. results. We suspect this is a result of small-scale flow differences due to the weak zones. Using these simple 2D systems, we systematically build toward a plate formulation with a temperature and stress dependent olivine rheology, then investigate the effects of damage and history. Lowman, J.P., S.D. King and C.W. Gable, The influence of tectonic plates on mantle convection patterns, temperature and heat flow, Geophysical Journal International, 146, 619-636, 2001. Scargle, J.D., Studies in Astronomical Time Series Analysis II. Statistical Aspects of Spectral Analysis of Unevenly Spaced Data, Astrophysical Journal, 263, 835-853, 1982. Benson, J.L., B.P. Bonev, P.B. James, K.J. Shan, B.A. Cantor, and M.A. Caplinger, The seasonal behavior of water ice clouds in the Tharsis and Valles Marineris Regions of Mars: Mars Orbiter Camera Observations, Icarus, 165, 34-52, 2003.

  6. New Eddy Current Probe for Thickness Gauging of Conductive Materials

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz; Fulton, Jim; Nath, Shridhar; Namkung, Min

    1993-01-01

    The accurate measure of material thickness is important for many non-destructive evaluation applications. Factors such as corrosion damage can jeopardize structural integrity through material thinning and process control considerations often mandate strict limits on material dimensions. Access to the material under test can be limited to a single side and large areas may need to be examined in a small time period. In an effort to enhance the effectiveness of material thickness measurements a flux focusing eddy current probe has been developed at NASA Langley Research Center. The probe provides an accurate measure of the thickness of conducting materials from a single sided measurement. It is straight forward to use and can be easily automated for production line testing. The probe also requires only minimal instrumentation and power so that extremely portable units can be manufactured at a low cost. This new eddy current probe has been used to accurately measure the thickness of aluminum alloy plates with a resolution of greater than 0.001 in. (25 microns). Simulated corrosion damage has also been detected on both single layer and multi-layer samples. The present work will explain the output voltage dependence of the device as a function of material thickness and present experimental results for thickness gauging and corrosion detection.

  7. Three-dimensional structure of the shell plate assembly of the chiton Tonicella marmorea and its biomechanical consequences.

    PubMed

    Connors, Matthew J; Ehrlich, Hermann; Hog, Martin; Godeffroy, Clemence; Araya, Sergio; Kallai, Ilan; Gazit, Dan; Boyce, Mary; Ortiz, Christine

    2012-02-01

    This study investigates the three-dimensional structure of the eight plate exoskeletal (shell) assembly of the chiton Tonicella marmorea. X-ray micro-computed tomography and 3D printing elucidate the mechanism of conformational change from a passive (slightly curved, attached to surface) to a defensive (rolled, detached from surface) state of the plate assembly. The passive and defensive conformations exhibited differences in longitudinal curvature index (0.43 vs. 0.70), average plate-to-plate overlap (?62% vs. ?48%), cross-sectional overlap heterogeneity (60-82.5% vs. 0-90%, fourth plate), and plate-to-plate separation distance (100% increase in normalized separation distance between plates 4 and 5), respectively. The plate-to-plate interconnections consist of two rigid plates joined by a compliant, actuating muscle, analogous to a geometrically structured shear lap joint. This work provides an understanding of how T. marmorea achieves the balance between mobility and protection. In the passive state, the morphometry of the plates and plate-to-plate interconnections results in an approximately continuous curvature and constant armor thickness, resulting in limited mobility but maximum protection. In the defensive state, the underlying soft tissues gain protection and the chiton gains mobility through tidal flow, but regions of vulnerability open dorsally, due to the increase in plate-to-plate separation and decrease in plate-to-plate overlap. Lastly, experiments using optical and scanning electron microscopy, mercury porosimetry, and Fourier-transform infrared spectroscopy explore the microstructure and spatial distribution of the six layers within the intermediate plates, the role of multilayering in resisting predatory attacks, and the detection of chitin as a major component of the intra-plate organic matrix and girdle. PMID:22248452

  8. Ultrasonic testing of plates containing edge cracks

    NASA Technical Reports Server (NTRS)

    Williams, J. H., Jr.; Lee, S. S.; Karagulle, H.

    1986-01-01

    The stress wave factor (SWF) signal is utilized for the nondestructive evaluation of plates containing perpendicular edge cracks. The effects of the existence lateral location and depth of the crack on the magnitude spectra of individual reflections in the SWF signal are studied. If the reflections in the SWF signal are not overlapped the short time Fourier analysis is applied. If the reflections are overlapped the short time homomorphic analysis (cepstrum analysis) is applied. Several reflections which have average resonant frequencies approximately at 0.9, 1.3, and 1.7 MHz are analyzed. It is observed that the magnitude ratios evaluated at average resonant frequencies decrease more with increasing d/h if the crack is located between the transducers, where h is plate thickness and d is crack depth. Moreover, for the plates, crack geometries, reflections, and frequencies considered, the average decibel drop depends mainly on the dimensionless parameter d/h and it is approximately -1 dB per 0.07 d/h. Changes in the average resonant frequencies of the magnitude spectra are also observed due to changes in the location of the crack.

  9. Ultrasonic testing of plates containing edge cracks

    NASA Technical Reports Server (NTRS)

    Williams, J. H., Jr.; Karagulle, H.; Lee, S. S.

    1985-01-01

    The stress wave factor (SWF) signal is utilized for the nondestructive evaluation of plates containing perpendicular edge cracks. The effects of the existence lateral location and depth of the crack on the magnitude spectra of individual reflections in the SWF signal are studied. If the reflections in the SWF signal are not overlapped the short time Fourier analysis is applied. If the reflections are overlapped the short time homomorphic analysis (cepstrum analysis) is applied. Several reflections which have average resonant frequencies approximately at 0.9, 1.3, and 1.7 MHz are analyzed. It is observed that the magnitude ratios evaluated at average resonant frequencies decrease more with increasing d/h if the crack is located between the transducers, where h is plate thickness and d is crack depth. Moreover, for the plates, crack geometries, reflections, and frequencies considered, the average decibel drop depends mainly on the dimensionless parameter d/h and it is approximately -1 dB per 0.07 d/h. Changes in the average resonant frequencies of the magnitude spectra are also observed due to changes in the location of the crack.

  10. Friction Stir Welding of Curved Plates

    NASA Technical Reports Server (NTRS)

    Sanchez, Nestor

    1999-01-01

    Friction stir welding (FSW) is a remarkable technology for making butt and lap joints in aluminum alloys. The process operates by passing a rotating tool between two closely butted plates. This process generates heat and the heated material is stirred from both sides of the plates to generate a high quality weld. Application of this technique has a very broad field for NASA. In particular, NASA is interested in using this welding process to manufacture tanks and curved elements. Therefore, this research has been oriented to the study the FSW of curved plates. The study has covered a number of topics that are important in the model development and to uncover the physical process involve in the welding itself. The materials used for the experimental welds were as close to each other as we could possibly find, aluminum 5454-0 and 5456-0 with properties listed at http://matweb.com. The application of FSW to curved plates needs to consider the behavior that we observed in this study. There is going to be larger force in the normal direction (Fz) as the curvature of the plate increases. A particular model needs to be derived for each material and thickness. A more complete study should also include parameters such as spin rate, tool velocity, and power used. The force in the direction of motion (Fx) needs to be reconsidered to make sure of its variability with respect to other parameters such as velocity, thickness, etc. It seems like the curvature does not play a role in this case. Variations in temperature were found with respect to the curvature. However, these changes seem to be smaller than the effect on Fz. The temperatures were all below the melting point. We understand now that the process of FSW produces a three dimensional flow of material that takes place during the weld. This flow needs to be study in a more detailed way to see in which directions the flow of material is stronger. It could be possible to model the flow using a 2-dimensional model in the particular directions where the flow moves faster. More experimental information is required to enrich the knowledge about FSW, and from this point, derive useful mathematical formulas to optimize the process and the design of the machines that will perform it. More experiments and experimental equipment are required to uncover the mathematics of the process.

  11. Plate heat exchanger design theory

    Microsoft Academic Search

    R. K. Shah; A. S. Wanniarachchi

    1991-01-01

    Plate heat exchangers are commonly used in hygienic applications as well as in chemical processing and other industrial applications. Pertinent information on plate exchangers from a designer's point of view is summarized to provide a basic insight into performance behavior of chevron plates. Basic design methods are presented and a method of coupling between heat transfer and pressure drop is

  12. Explosive welding of metal plates

    Microsoft Academic Search

    S. A. A. Akbari-Mousavi; L. M. Barrett; S. T. S. Al-Hassani

    2008-01-01

    This paper describes a study of explosive welding of metal plates. The properties of a locally prepared mix of 77\\/23 ammonium nitrate and fuel oil (ANFO) explosive and the dynamics of the plates are investigated and the results from welding tests presented. The strength of the clad plates is measured and ultrasonic inspection performed to identify and locate defects. The

  13. Lesson 3. Plate Tectonics Overview

    E-print Network

    Chen, Po

    Lesson 3. Plate Tectonics #12;Overview · Prior to the 1970s that with the development of the theory of plate tectonics. · Knowledge of the ocean floors of the Earth #12;Overview · Plate tectonics explains the formaBon of the Earth's two

  14. Tectonic stress in the plates

    Microsoft Academic Search

    Randall M. Richardson; Sean C. Solomon; Norman H. Sleep

    1979-01-01

    The state of stress in the lithosphere provides strong constraints on the forces acting on the plates. The directions of principal stresses in the plates as indicated by midplate earthquake mechanisms, in situ stress measurements, and stress-sensitive geological features are used to test plate tectonic driving force models, under the premises that enough data exist in selected areas to define

  15. Inverse methods for modeling non-rigid plate kinematics: Application to mesozoic plate reconstructions of the Central Atlantic

    NASA Astrophysics Data System (ADS)

    Kneller, Erik A.; Johnson, Christopher A.; Karner, Garry D.; Einhorn, Jesse; Queffelec, Thomas A.

    2012-12-01

    Published plate reconstructions commonly show significant differences in initial plate configuration and syn-extensional opening directions. The variability of published models is primarily due to the difficulty associated with restoring crustal stretching history. Here we present an inverse non-rigid kinematic method that inverts plate motion and present day crustal thickness to approximate the history of bulk lateral strain and crustal thinning associated with lithospheric stretching. The kinematic link between plate motion and bulk crustal thickness that is used with this method is based on insights obtained from geodynamic models. We implement this approach in open source kinematic modeling software and apply it to test new Early Mesozoic plate kinematic models of the Central Atlantic. This application shows that the patterns of stretching inferred from the syn-rift basins of the Newark Supergroup can be explained if (1) syn-rift Euler pole flow lines were parallel to the Grand Banks transform margin and (2) initial formation of the East Coast Margin Igneous Province was coincident with the formation of the Central Atlantic Magmatic Province. These syn-rift to breakup models of the Central Atlantic lead to better constrained models of early seafloor spreading that show full spreading velocities in the ultraslow regime and within the transition from ultraslow to slow spreading regimes.

  16. On the breakup of tectonic plates by polar wandering

    NASA Technical Reports Server (NTRS)

    Liu, H.-S.

    1974-01-01

    The equations for the stresses in a homogeneous shell of uniform thickness caused by a shift of the axis of rotation are derived. The magnitude of these stresses reaches a maximum value of the order of 10 to the 9th power dyn/sq cm, which is sufficient for explaining a tectonic breakup. In order to deduce the fracture pattern according to which the breakup of tectonic plates can be expected the theory of plastic deformation of shells is applied. The analysis of this pattern gives an explanation of the existing boundary systems of the major tectonic plates as described by Morgan (1968), LePichon (1968) and Isacks et al. (1968).

  17. Fractal Generalized Zone Plates

    E-print Network

    Mendoza-Yero, Omel; Minguez-Vega, Gladys; Lancis, Jesus; Climent, Vicent; Monsoriu, Juan A

    2008-01-01

    The construction of fractal generalized zone plates (FraGZPs) from a set of periodic diffractive optical elements with circular symmetry is proposed. This allows us to increase the number of foci of a conventional fractal zone plate (FraZP), keeping the self-similarity property within the axial irradiance. The focusing properties of these fractal diffractive optical elements for points not only along but also in the close vicinity of the optical axis are investigated. In both cases analytical expressions for the irradiance are derived. Numerical simulations of the energetic efficiency of FraGZPs under plane wave illumination are carried out. In addition, some effects on the axial irradiance caused by the variation in area of their transparent rings are shown.

  18. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1984-09-28

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (uv to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 keV x-rays.

  19. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1989-03-21

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras is disclosed. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1,000 KeV x-rays. 3 figs.

  20. Microchannel plate streak camera

    DOEpatents

    Wang, Ching L. (Livermore, CA)

    1989-01-01

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

  1. Elastically suspending the screw holes of a locked osteosynthesis plate can dampen impact loads.

    PubMed

    Capanni, Felix; Hansen, Kirk; Fitzpatrick, Daniel C; Madey, Steven M; Bottlang, Michael

    2015-06-01

    Impact damping by elastic fixation is a principal engineering strategy to increase the durability of load-bearing structures exposed to prolonged dynamic loading. This biomechanical study evaluated axial impact damping provided by a novel dynamic locking plate. In this design, locking screw holes are elastically suspended within a silicone envelope inside the locking plate. Axial impact damping was assessed for 3 distinct fixation constructs applied to bridge a 10-mm fracture gap of a femoral diaphysis surrogate: a standard locking plate, a dynamic locking plate, and an Ilizarov ring fixator. First, the 3 fixation constructs were characterized by determining their axial stiffness. Subsequently, constructs were subjected to a range of axial impact loads to quantify damping of force transmission. Compared with standard locked plating constructs, dynamic plating constructs were 58% less stiff (P < .01) and Ilizarov constructs were 88% less stiff (P < .01). Impact damping correlated inversely with construct stiffness. Compared with standard plating, dynamic plating constructs and Ilizarov constructs dampened the transmission of impact loads by up to 48% (P < .01) and 74% (P < .01), respectively. In conclusion, lower construct stiffness correlated with superior damping of axial impact loads. Dynamic locking plates provide significantly greater impact damping compared with standard locking plates. PMID:25642697

  2. Plate Tectonics: The Mechanism

    NSDL National Science Digital Library

    This text explains how detailed mapping of the ocean floor led scientists like Howard Hess and R. Deitz to revive the Holmes convection theory. Hess and Deitz modified the theory considerably and called their new theory Sea-floor Spreading. Among the seafloor features that supported the sea-floor spreading hypothesis were: mid-oceanic ridges, deep sea trenches, island arcs, geomagnetic patterns, and fault patterns. These features are treated in detail and related to the current Theory of Plate Tectonics.

  3. Plate motion and deformation

    SciTech Connect

    Minster, B.; Prescott, W.; Royden, L.

    1991-02-01

    Our goal is to understand the motions of the plates, the deformation along their boundaries and within their interiors, and the processes that control these tectonic phenomena. In the broadest terms, we must strive to understand the relationships of regional and local deformation to flow in the upper mantle and the rheological, thermal and density structure of the lithosphere. The essential data sets which we require to reach our goal consist of maps of current strain rates at the earth's surface and the distribution of integrated deformation through time as recorded in the geologic record. Our success will depend on the effective synthesis of crustal kinematics with a variety of other geological and geophysical data, within a quantitative theoretical framework describing processes in the earth's interior. Only in this way can we relate the snapshot of current motions and earth structure provided by geodetic and geophysical data with long-term processes operating on the time scales relevant to most geological processes. The wide-spread use of space-based techniques, coupled with traditional geological and geophysical data, promises a revolution in our understanding of the kinematics and dynamics of plate motions over a broad range of spatial and temporal scales and in a variety of geologic settings. The space-based techniques that best address problems in plate motion and deformation are precise space-geodetic positioning -- on land and on the seafloor -- and satellite acquisition of detailed altimetric and remote sensing data in oceanic and continental areas. The overall science objectives for the NASA Solid Earth Science plan for the 1990's, are to Understand the motion and deformation of the lithosphere within and across plate boundaries'', and to understand the dynamics of the mantle, the structure and evolution of the lithosphere, and the landforms that result from local and regional deformation. 57 refs., 7 figs., 2 tabs.

  4. Alumina plate containing photosystem I reaction center complex oriented inside plate-penetrating silica nanopores.

    PubMed

    Kamidaki, Chihiro; Kondo, Toru; Noji, Tomoyasu; Itoh, Tetsuji; Yamaguchi, Akira; Itoh, Shigeru

    2013-08-22

    The photosynthetic photosystem I reaction center complex (PSI-RC), which has a molecular diameter of 21 nm with 100 pigments, was incorporated into silica nanopores with a 100-nm diameter that penetrates an alumina plate of 60-?m thickness to make up an inorganic-biological hybrid photocell. PSI-RCs, purified from a thermophilic cyanobacterium, were stable inside the nanopores and rapidly photoreduced a mediator dye methyl viologen. The reduced dye was more stable inside nanopores suggesting the decrease of dissolved oxygen. The analysis by a cryogenic electron spin paramagnetic resonance indicated the oriented arrangement of RCs inside the 100-nm nanopores, with their surface parallel to the silica wall and perpendicular to the plane of the alumina plate. PSI RC complex in the semicrystalline orientation inside silica nanopores can be a new type of light energy conversion unit to supply strong reducing power selectively to other molecules inside or outside nanopores. PMID:23888886

  5. Buckling of trapezoidal plates

    SciTech Connect

    Radloff, H.D. [Sandia National Lab., Albuquerque, NM (United States); Hyer, M.W. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States); Nemeth, M.P. [NASA - Langley Research Center, Hampton, VA (United States)

    1995-12-31

    This study focuses on the buckling response of flat composite plates with an isosceles planform, as shown below. The study consisted of both analytical and experimental phases. In the study the parallel edges x = 0 and L were clamped or simply supported. Clamped parallel edges were used in the experimental phase of the study. The nonparallel edges were simply supported. The parallel edges were assumed to remain straight and buckling was assumed to occur because these edges moved toward each other. A Rayleigh-Ritz approach was used, with the finite-element code ABAQUS being used to check specific cases. The buckling displacements were assumed to be in the form of harmonic functions. The prebuckling force resultant N{sub x} was assumed to be given by N{sub x}(x,y) = P/W(x), where P is the applied load and W(x) is the varying width of the plate. N{sub y}(x,y) and N{sub x,y}(x,y) were taken to be zero. Experiments were conducted on a number of laminates and a number of plate geometries, and the results were compared to predictions of the Rayleigh-Ritz scheme. In general correlation was good, though the analysis underpredicted the number of buckling half-waves.

  6. Discovering Plate Boundaries

    NSDL National Science Digital Library

    Dale Sawyer

    1997-09-15

    Discovering Plate Boundaries is based on 5 world maps containing earthquake, volcano, topography, satellite gravity, and seafloor age data. The novel aspect of the exercise is the "jigsaw" manner in which student groups access the maps and use them to discover, classify, and describe plate boundary types. The exercise is based only on observation and description, which makes it useful at a wide variety of levels; it has been used successfully in 5th grade classes, as well as in non-major earth science classes. The exercise is based on a set of wall maps that are not consumed during the exercise. Other inexpensive materials required include two 11x17 black and white copies per student and colored pencils. Because the exercise is not based on student access to the web, it is not dependent on classroom technology equipment. The exercise takes three 50-minute class periods to complete, and involves the students in making presentations to one another in small groups as well as to the whole class. The students come away from the exercise with knowledge of the key features of each type of plate boundary and a sense of why each looks and acts the way it does.

  7. Measuring Thicknesses of Wastewater Films

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Davenport, R. J.

    1987-01-01

    Sensor determines when thickness of film of electrically conductive wastewater on rotating evaporator drum exceeds preset value. Sensor simple electrical probe that makes contact with liquid surface. Made of materials resistant to chemicals in liquid. Mounted on shaft in rotating cylinder, liquid-thickness sensor extends toward cylinder wall so tip almost touches. Sensor body accommodates probe measuring temperature of evaporated water in cylinder.

  8. Thin layer thickness measurements by zero group velocity Lamb mode resonances.

    PubMed

    Cès, Maximin; Clorennec, Dominique; Royer, Daniel; Prada, Claire

    2011-11-01

    Local and non-contact measurements of the thickness of thin layers deposited on a thick plate have been performed by using zero group velocity (ZGV) Lamb modes. It was shown that the shift of the resonance frequency is proportional to the mass loading through a factor which depends on the mechanical properties of the layer and of the substrate. In the experiments, ZGV Lamb modes were generated by a Nd:YAG pulsed laser and the displacement normal to the plate surface was measured by an optical interferometer. Measurements performed at the same point that the generation on the non-coated face of the plate demonstrated that thin gold layers of a few hundred nanometers were detected through a 1.5-mm thick Duralumin plate. The shift of the resonance frequency (1.9 MHz) of the fundamental ZGV mode is proportional to the layer thickness: typically 10 kHz per ?m. Taking into account the influence of the temperature, a 240-nm gold layer was measured with a ±4% uncertainty. This thickness has been verified on the coated face with an optical profiling system. PMID:22128999

  9. Thin layer thickness measurements by zero group velocity Lamb mode resonances

    NASA Astrophysics Data System (ADS)

    Cès, Maximin; Clorennec, Dominique; Royer, Daniel; Prada, Claire

    2011-11-01

    Local and non-contact measurements of the thickness of thin layers deposited on a thick plate have been performed by using zero group velocity (ZGV) Lamb modes. It was shown that the shift of the resonance frequency is proportional to the mass loading through a factor which depends on the mechanical properties of the layer and of the substrate. In the experiments, ZGV Lamb modes were generated by a Nd:YAG pulsed laser and the displacement normal to the plate surface was measured by an optical interferometer. Measurements performed at the same point that the generation on the non-coated face of the plate demonstrated that thin gold layers of a few hundred nanometers were detected through a 1.5-mm thick Duralumin plate. The shift of the resonance frequency (1.9 MHz) of the fundamental ZGV mode is proportional to the layer thickness: typically 10 kHz per ?m. Taking into account the influence of the temperature, a 240-nm gold layer was measured with a ±4% uncertainty. This thickness has been verified on the coated face with an optical profiling system.

  10. Standardization versus Standards.

    ERIC Educational Resources Information Center

    Meier, Deborah

    2002-01-01

    Examines differences between old state-designed norm-referenced tests and new tests aligned with the curriculum. Concludes that new state tests are very similar to old ones. Discusses impact of new high-stakes standardized tests on students and teachers. Argues the new wave of standardized testing is not the answer to improving student…

  11. Some experimental findings in compression-after-impact (CAI) tests of CF\\/PEEK (APC2) and conventional CF\\/epoxy flat plates

    Microsoft Academic Search

    Takashi Ishikawa; Sunao Sugimoto; Masamichi Matsushima; Yoichi Hayashi

    1995-01-01

    Compression-after-impact (CAI) tests have been conducted for quasi-isotropic thick plates with 48 plies by using the NASA method and on plates with 32 plies by using the SACMA method. Specimens are made of CF\\/PEEK (APC-2) and conventional CF\\/epoxy for the NASA plates and CF\\/epoxy for the SACMA plates. In the NASA CAI tests, the sequence of delamination buckling and its

  12. Quantitative assessment of macular thickness in normal subjects and patients with diabetic retinopathy by scanning retinal thickness analyser

    PubMed Central

    Oshima, Y.; Emi, K.; Yamanishi, S.; Motokura, M.

    1999-01-01

    AIMS—To evaluate the scanning retinal thickness analyser (RTA), a novel non-invasive imaging instrument, in diagnosing and quantitatively characterising diabetic macular oedema, and to investigate the relation between central macula thickness measured by RTA and other clinical examinations.?METHODS—Central macular thickness was measured using the RTA in 40 normal subjects and 60 patients with diabetic retinopathy. The reproducibility of the retinal thickness measurements was evaluated by calculating the mean of the inter- and intrasession variations. Central macular thickness was correlated with the results of visual acuity measurements, biomicroscopy, and fluorescein angiography.?RESULTS—Intra- and intersession reproducibility of the RTA in normal subjects was plus or minus 5.2% (16 µm) and plus or minus 6.1% (19 µm), respectively. The mean central macular thickness was 182 (SD 16) µm in normal subjects, 283 (116) µm in diabetic eyes without clinically significant macular oedema (CSMO), and 564 (168) µm in diabetic eyes with CSMO. Central macular thickness was significantly greater (p<0.001) in eyes with diabetic retinopathy than in normal subjects, even when macular thickening did not meet the standard for CSMO (p=0.019) measured by biomicroscopy. Although greater fluorescein leakage at the macula results in greater central macular thickness, only eyes with diffuse leakage had statistically significant macular thickening compared with normal subjects (p=0.022). Central macular thickness measured with the RTA was significantly correlated with the logarithmic converted visual acuity (r2= 0.76) in diabetic eyes.?CONCLUSION—Scanning RTA, which has good reproducibility, might be useful to quantitatively detect and monitor macular thickening in diabetic retinopathy. Central macular thickness was highly correlated with logarithmic converted visual acuity in diabetic macular oedema.?? Keywords: scanning retinal thickness analyser; macular thickness; diabetic retinopathy; macular oedema PMID:10209436

  13. Design and experimental evaluation of adjustable bone plates for mandibular fracture fixation.

    PubMed

    Cervantes, Thomas M; Slocum, Alexander H; Seldin, Edward B

    2012-01-01

    Conventional bone plates are commonly used for surgical mandibular fracture fixation. Improper alignment between bone segments, however, can result in malocclusion. Current methods of fixation require a surgeon to visually align segments of bone and affix a metal plate using bone screws, after which little can be done to adjust alignment. A method of adjusting fracture alignment after plate placement, without screw removal, presents an improvement over costly and risky revision surgery. A modified bone plate has been designed with a deformable section to give surgeons the ability to reduce misalignments at the fracture site. The mechanics of deformation for various adjustment mechanisms was explored analytically, numerically, and experimentally to ensure that the adjustable plate is comparable to conventional bone plates. A static force of 358.8 N is required to deform the adjustable bone plate, compared with predicted values of 351 N using numerical simulation and 362 N using a simple beam theory. Dynamic testing was performed to simulate in vivo loading conditions and evaluate load-capacity in both deformed and un-deformed bone plates. Results indicate that bending stiffness of a rectangular bone plate is 709 N/mm, compared with 174 N/mm for an octagonal plate and 176 N/mm for standard plates. Once deformed, the rectangular and octagonal plates had a stiffness of 323 N/mm and 228 N/mm, respectively. Un-deformed and deformed adjustable bone plates have efficacy in bone segment fixation and healing. PMID:22036033

  14. On pulse pressure loading of plates with holes

    NASA Astrophysics Data System (ADS)

    Schleyer, Graham K.; Underwood, Nicholas. J.; Do, Hyung Min; Paik, Jeom Kee; Kim, Bong Ju

    2012-12-01

    This paper reports the application of an energy solution to a complex problem involving large inelastic deformation in thin, clamped ductile square plates with either square or circular holes under the action of transverse pulse pressure loading. The work is part of a collaborative project to study blast loading of steel plates with penetrations as used for deck plating or bulkheads that may be required to resist loading far in excess of their design limit due to the effects of an accidental explosion. A novel differential pressure loading device was used to impart dynamic loading to 1/8 scaled 0.5 m, 1.1 mm thick, clamped mild steel square plates with a central aperture up to 4% of the plate area. This data was used to validate the energy approach that considers both plastic hinge formation and extensional effects. Accounting for strain rate, scaling and dynamic effects in the tests gave more than acceptable results when compared with final deflections in the tested plates. It is concluded that the energy approach together with small-scale test validation paves the way for a versatile robust design methodology which can be used to advantage for screening purposes and/or early stage conceptual design studies.

  15. Methods of localization of Lamb wave sources on thin plates

    NASA Astrophysics Data System (ADS)

    Turkaya, Semih; Toussaint, Renaud; Kvalheim Eriksen, Fredrik; Daniel, Guillaume; Grude Flekkøy, Eirik; Jørgen Måløy, Knut

    2015-04-01

    Signal localization techniques are ubiquitous in both industry and academic communities. We propose a new localization method on plates which is based on energy amplitude attenuation and inverted source amplitude comparison. This inversion is tested on synthetic data using Lamb wave propagation direct model and on experimental dataset (recorded with 4 Brüel & Kjær Type 4374 miniature piezoelectric shock accelerometers (1-26 kHz frequency range)). We compare the performance of the technique to the classical source localization algorithms, arrival time localization, time reversal localization, localization based on energy amplitude. Furthermore, we measure and compare the accuracy of these techniques as function of sampling rate, dynamic range, geometry, Signal to Noise Ratio, and we show that this very versatile technique works better than classical ones over the sampling rates 100kHz - 1MHz. Experimental phase consists of a glass plate having dimensions of 80cmx40cm with a thickness of 1cm. Generated signals due to a wooden hammer hit or a steel ball hit are captured by sensors placed on the plate on different locations with the mentioned sensors. Numerical simulations are done using dispersive far field approximation of plate waves. Signals are generated using a hertzian loading over the plate. Using imaginary sources outside the plate boundaries the effect of reflections is also included. This proposed method, can be modified to be implemented on 3d environments, monitor industrial activities (e.g boreholes drilling/production activities) or natural brittle systems (e.g earthquakes, volcanoes, avalanches).

  16. PLATE WAVE RESONANCE WITH AIR-COUPLED ULTRASONICS

    SciTech Connect

    Bar, H. N. [National Metallurgical Laboratory, Jamshedpur, India 831007 (India); Dayal, V.; Barnard, D.; Hsu, D. K. [Center for Nondestructive Evaluation, Iowa State University, Ames, IA 50011 (United States)

    2010-02-22

    Air-coupled ultrasonic transducers can excite plate waves in metals and composites. The coincidence effect, i.e., the wave vector of plate wave coincides with projection of exciting airborne sound vector, leads to a resonance which strongly amplifies the sound transmission through the plate. The resonance depends on the angle of incidence and the frequency. In the present study, the incidence angle for maximum transmission (theta{sub max}) is measured in plates of steel, aluminum, carbon fiber reinforced composites and honeycomb sandwich panels. The variations of (theta{sub max}) with plate thickness are compared with theoretical values in steel, aluminum and quasi-isotropic carbon fiber composites. The enhanced transmission of air-coupled ultrasound at oblique incidence can substantially improve the probability of flaw detection in plates and especially in honeycomb structures. Experimental air-coupled ultrasonic scan of subtle flaws in CFRP laminates showed definite improvement of signal-to-noise ratio with oblique incidence at theta{sub max}.

  17. Etching and plating of nominal U-6 wt % Nb alloys

    SciTech Connect

    Johnson, H.R.; Dini, J.W.; Wood, D.H.

    1980-08-01

    The adhesion of electrodeposited nickel to U-Nb alloys is of interest for joining materials by plating and for protection from corrosive environments. Because uranium alloys are passive, a surface preparation procedure such as etching in acid is necessary before plating to provide mechanical keying of the electrodeposit. When nitric acid has served as the etchant, there have been occasional violent reactions between the oxidizing acid and the alloy. We have observed that a sulfuric acid/hydrochloric acid etchant eliminates this problem. Furthermore, quantitative test data for nominal U-6 wt % Nb alloys plated with nickel demonstrated that with parts etched anodically in a solution of sulfuric and hydrochloric acids, high-strength bonds can be obtained; nominal shear and tensile bond strengths were 250 and 115 MN/m/sup 2/ respectively. Electrochemically etched U-Nb rods joined to 7075-T6 Al rods with thick nickel plating showed a nominal fracture stress in excess of 470 MN/m/sup 2/. Bare and Ni-plated tensile bars showed no significant changes in mechanical properties due to electrochemical etching and plating, but did exhibit changes due to Nb content and heat treatment.

  18. Crustal Structure of the Tengchong Intra-plate Volcanic Area

    NASA Astrophysics Data System (ADS)

    Qian, Rongyi; Tong, Vincent C. H.

    2015-05-01

    We here provide an overview of our current understanding of the crustal structure of Tengchong in southwest China, a key intra-plate volcanic area along the Himalayan geothermal belt. Given that there is hitherto a lack of information about the near-surface structure of intra-plate volcanic areas, we present the first seismic reflection and velocity constraints on the shallow crust between intra-plate volcanoes. Our near-surface seismic images reveal the existence of dome-shaped seismic reflectors (DSRs) in the shallow crust between intra-plate volcanic clusters in Tengchong. The two DSRs are both ~2 km wide, and the shallowest parts of the DSRs are found at the depth of 200-300 m. The velocity model shows that the shallow low-velocity layer (<4 km/s) is anomalously thick (~1 km) in the region where the DSRs are observed. The presence of DSRs indicates significant levels of intra-plate magmatism beneath the along-axis gap separating two volcano clusters. Along-axis gaps between volcano clusters are therefore not necessarily an indicator of lower levels of magmatism. The seismic images obtained in this technically challenging area for controlled-source seismology allow us to conclude that shallow crustal structures are crucial for understanding the along-axis variations of magmatism and hydrothermal activities in intra-plate volcanic areas.

  19. A model of convergent plate margins based on the recent tectonics of Shikoku, Japan

    NASA Technical Reports Server (NTRS)

    Bischke, R. E.

    1974-01-01

    A viscoelastic finite element plate tectonic model is applied to displacement data for the island of Shikoku, Japan. The flow properties and geometry of the upper portions of the earth are assumed known from geophysical evidence, and the loading characteristics are determined from the model. The nature of the forces acting on the Philippine Sea plate, particularly in the vicinity of the Nankai trough, is determined. Seismic displacement data related to the 1946 Nankaido earthquake are modeled in terms of a thick elastic plate overlying a fluidlike substratum. The sequence of preseismic and seismic displacements can be explained in terms of two independent processes operating on elastic lithospheric plates: a strain accumulation process caused by vertical downward forces acting on or within the lithosphere in the vicinity of the trench, and a strain release process caused by plate failure along a preexisting zone on weakness. This is a restatement of Reid's elastic rebound theory in terms of elastic lithospheric plates.

  20. Thermal residual stresses in thick graphite\\/epoxy composite laminates—Uniaxial approach

    Microsoft Academic Search

    D. Joh; K. Y. Byun; J. Ha

    1993-01-01

    Thermal residual stresses have been known to be very large in laminates of continuous-fiber-reinforced polymer composites.\\u000a When the thickness of the laminate is large, however, the measurement of the residual stresses raises questions on the accuracy\\u000a of the conventional methods. A novel concept of layer separation is developed to measure quantitatively and precisely the\\u000a tensile residual stresses in thick plates

  1. A variable-order laminated plate theory based on the variational-asymptotical method

    NASA Technical Reports Server (NTRS)

    Lee, Bok W.; Sutyrin, Vladislav G.; Hodges, Dewey H.

    1993-01-01

    The variational-asymptotical method is a mathematical technique by which the three-dimensional analysis of laminated plate deformation can be split into a linear, one-dimensional, through-the-thickness analysis and a nonlinear, two-dimensional, plate analysis. The elastic constants used in the plate analysis are obtained from the through-the-thickness analysis, along with approximate, closed-form three-dimensional distributions of displacement, strain, and stress. In this paper, a theory based on this technique is developed which is capable of approximating three-dimensional elasticity to any accuracy desired. The asymptotical method allows for the approximation of the through-the-thickness behavior in terms of the eigenfunctions of a certain Sturm-Liouville problem associated with the thickness coordinate. These eigenfunctions contain all the necessary information about the nonhomogeneities along the thickness coordinate of the plate and thus possess the appropriate discontinuities in the derivatives of displacement. The theory is presented in this paper along with numerical results for the eigenfunctions of various laminated plates.

  2. Modeling and magnetoelectric properties of laminate composite of nickel plate and piezoelectric multilayer vibrator

    NASA Astrophysics Data System (ADS)

    Guo, Ze-Qing; Zhang, Sai-Huan; Zhou, Jian-Ping; Shi, Zhan; Zhang, Guang-Bin; Deng, Chao-Yong

    2014-05-01

    A magnetoelectric theoretical model combing piezoelectric and piezomagnetic parts about the longitudinal vibration was proposed for the laminate composite based on equivalent circuit. The model shows that the magnetoelectric voltage is relative to the thickness ratio, total thickness, frequency and loss. A simple laminate magnetoelectric composite was prepared by bonding a nickel plate and a multilayer piezoelectric vibrator together for the experimental research. The multilayer vibrator enjoys high capacitance, large effective area and low thickness, leading to a high magnetic field sensitivity of 1 mOe at the magnetoelectric field coefficient of 2.58 V/cmOe in the simple composite with nickel thickness of 0.2 mm. The model fits the resonance frequency well with the experimental results. Numerical calculation well predicates the magnetoelectric experimental behaviors, presenting a magnetoelectric maximum at about the thickness ratio 0.3 between the nickel plate and multilayer vibrators. This approach provides a method for the magnetoelectric application.

  3. Electrochemical Machining of Metal Plates

    SciTech Connect

    Cooper, J F; Evans, M C

    2005-03-04

    Electrochemical machining (ECM) with concentrated sodium chlorate electrolyte was used to rapidly cut a circular groove (13 cm diameter, 0.2 cm wide) through a 0.15 cm thick sheet of steel--thus opening a 5-inch porthole in as little as 10 minutes. The most favorable operating conditions were: T = 22 C; chlorate concentration 600 g NaClO{sub 3}/liter-solution; electric power of 100 A at 10 V; and flow of 0.5 l/s at a pressure drop of 10 kPa (1.5 psi). The porthole may be removed entirely by electrochemical means, or the electrochemical dissolution may continue until only thin membrane remains that is subsequently cut with a utility knife. An array of thermocouples was used to track temperature in the flowing solution and in the trough being machined; the maximum increase in temperature in the trough was 5 C over that of the flowing electrolyte which increased in temperature by 19 C because of power dissipation. ECM is shown feasible for rapid perforation of plates of ferrous and non-ferrous metals using portable equipment and commercial batteries. The technique can be extended to cut perforations of arbitrary shape through non-planar surfaces using a deformable ring cathode. Analysis of the power requirements for electrolyte flow and ECM indicate a total system weight of less than 45 kg (100 lb) using a commercial NiMH battery. The technique is recommended for reduction to practice and demonstration on full scale as an engineering prototype.

  4. A co-rotational 8-node assumed strain shell element for postbuckling analysis of laminated composite plates and shells

    Microsoft Academic Search

    K. D. Kim; G. R. Lomboy; S. C. Han

    2003-01-01

    The formulation of a nonlinear composite shell element is presented for the solution of stability problems of composite plates and shells. The formulation of the geometrical stiffness presented here is exactly defined on the midsurface and is efficient for analyzing stability problems of thin and thick laminated plates and shells by incorporating bending moment and transverse shear resultant forces. The

  5. Adiabatic compression of parallel-plate metal waveguides for sensitivity enhancement of waveguide THz time-domain spectroscopy

    E-print Network

    by probing nanometer water layers.7 The sensitivity of waveguide THz-TDS is inversely proportional of two identical copper plates, with dimensions of 63.5 mm length 27.9 mm width 9.5 mm thickness . The copper plates were hand-polished to a mirror finish with submicron flatness. The cylindrical silicon

  6. Investigation into the Response of Fully Clamped Circular Steel, Copper, and Aluminum Plates Subjected to Shock Loading

    Microsoft Academic Search

    H. Babaei; A. Darvizeh

    2011-01-01

    The plastic responses of clamped mild steel, copper, and aluminum circular plates subjected to blast loads are investigated. In this way, extensive experimental results concerning the variations of central deflection and natural strain distributions are presented. The effects of plate thickness, stand-off distance, and material properties on the mid-point deflection, on the deformation profile and on the natural strain distributions

  7. Shape from equal thickness contours

    SciTech Connect

    Cong, G.; Parvin, B.

    1998-05-10

    A unique imaging modality based on Equal Thickness Contours (ETC) has introduced a new opportunity for 3D shape reconstruction from multiple views. We present a computational framework for representing each view of an object in terms of its object thickness, and then integrating these representations into a 3D surface by algebraic reconstruction. The object thickness is inferred by grouping curve segments that correspond to points of second derivative maxima. At each step of the process, we use some form of regularization to ensure closeness to the original features, as well as neighborhood continuity. We apply our approach to images of a sub-micron crystal structure obtained through a holographic process.

  8. Tethered Triangular Plate

    NSDL National Science Digital Library

    Zhang, Zhenli

    2005-01-31

    Simulation Software: Glotzer Group Code Simulation Method: Brownian Dynamics BD simulation of polymer tethered triangular plates. A system of building blocks of composition P10bT18b at a concentration of 0.20, was run starting at an effectively infinite temperature then instantaneously quenched to a temperature of 0.83. The system was then run for 12,000,000 time steps forming a hexagonally packing twisted columnar phase.The solve was favorable for the tethers. Simulation Model: United Atom Bead Spring with Lennard-Jones and FENE

  9. Plates on the Move

    NSDL National Science Digital Library

    In this activity, students create a model of sea floor spreading using two sheets of white paper and a metric ruler. The paper strips are pulled through a slit representing a mid-ocean ridge and divergent plate boundary. The model mimics how molten material rises to the surface and then spreads out in both directions. The resource is part of the teacher's guide accompanying the video, NASA SCI Files: The Case of the Shaky Quake. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.

  10. Dynamics of Tectonic Plates

    E-print Network

    Pechersky, E; Sadowski, G; Yambartsev, A

    2014-01-01

    We suggest a model that describes a mutual dynamic of tectonic plates. The dynamic is a sort of stick-slip one which is modeled by a Markov random process. The process defines a microlevel of the dynamic. A macrolevel is obtained by a scaling limit which leads to a system of integro-differential equations which determines a kind of mean field systems. Conditions when Gutenberg-Richter empirical law are presented on the mean field level. These conditions are rather universal and do not depend on features of resistant forces.

  11. Design of round-robin tests with guarded/calibrated hot boxes, guarded hot plates, and heat flow meters

    SciTech Connect

    Powell, F.J.; Bales, E.L.

    1983-01-01

    Design and procedures for three round-robin tests of thermal insulation materials are described. The first, sponsored by ASTM Committee C-16 on Thermal Insulation, was intended to produce calibration and precision and accuracy data for ASTM Test for Thermal Conductance and Transmittance of Built-Up Sections by Means of the Guarded Hot Box (C 236) and a draft ASTM standard for a calibrated hot box test. The second, sponsored by International Standards Organization Technical Committee 163 on Thermal Insulation, covered guarded hot plate and heat flow meter tests of thermal resistance of thick thermal insulation materials, and was intended to produce calibration and precision and accuracy data for ISO specifications for such tests and those of each of the 22 participating countries - in the United States, ASTM Test for Steady-State Thermal Transmission Properties by Means of the Guarded Hot Plate (C 177) and ASTM Test for Steady-State Thermal Transmission properties by Means of Heat Flow Meter (C 518). The third round-robin test involved tests of glass-fiber insulating material and was sponsored by ASTM Subcommittee C16.30 on Thermal Measurement and the Mineral Insulation Manufacturers Association.

  12. Study of gas tungsten arc welding procedures for tantalum alloy T-111 (Ta-8 W-2Hf) plate

    NASA Technical Reports Server (NTRS)

    Gold, R. E.; Kesterson, R. L.

    1973-01-01

    Methods of eliminating or reducing underbread cracking in multipass GTA welds in thick T-111 plate were studied. Single V butt welds prepared using experimental filler metal compositions and standard weld procedures resulted in only moderate success in reducing underbread cracking. Subsequent procedural changes incorporating manual welding, slower weld speeds, and three or fewer fill passes resulted in crack-free single V welds only when the filler metal was free of hafnium. The double V joint design with successive fill passes on opposite sides of the joint produced excellent welds. The quality of each weld was determined metallographically since the cracking, when present, was very slight and undetectable using standard NDT techniques. Tensile and bend tests were performed on selected weldments. The inherent filler metal strength and the joint geometry determined the strength of the weldment. Hardness and electron beam microprobe traverses were made on selected specimens with the result that significant filler metal-base metal dilution as well as hafnium segregation was detected. A tentative explanation of T-111 plate underbread cracking is presented based on the intrinsic effects of hafnium in the weldment.

  13. Plating on difficult-to-plate metals: what's new

    SciTech Connect

    Wiesner, H.J.

    1980-07-30

    Some of the changes since 1970 in procedures for plating on such materials as titanium, molybdenum, silicon, aluminum, and gallium arsenide are summarized. While basic procedures for plating some of these materials were developed as many as 30 to 40 years ago, changes in the end uses of the plated products have necessitated new plating processes. In some cases, vacuum techniques - such as ion bombardment, ion implantation, and vacuum metallization - have been introduced to improve the adhesion of electrodeposits. In other cases, these techniques have been used to deposit materials upon which electrodeposits are required.

  14. Plate tectonics on Venus

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1981-01-01

    The high surface temperature of Venus implies a permanently buoyant lithosphere and a thick basaltic crust. Terrestrial-style tectonics with deep subduction and crustal recycling is not possible. Overthickened basaltic crust partially melts instead of converting to eclogite. Because mantle magmas do not have convenient access to the surface the Ar-40 abundance in the atmosphere should be low. Venus may provide an analog to Archean tectonics on the earth.

  15. Shock initiation of PBX9404 by electrically driven flyer plates

    Microsoft Academic Search

    R. C. Weingart; R. K. Jackson; C. A. Honodel; R. S. Lee

    1979-01-01

    The shock initiation threshold of PBX-9404 was studied over the pressure range from 3.1 to 28 GPa with pulse lengths ranging from 0.007 to 0.063 ..mu..s. The short-duration, high pressure pulses were produced by the impact of thin flyer plates accelerated by electrically exploded metal foils. The experiments were performed on explosive pellets 25.4 mm in dia with thicknesses of

  16. Remote measurement of in-plane diffusivity components in plates

    Microsoft Academic Search

    Christopher S. Welch; D. Michele Heath; William P. Winfree

    1987-01-01

    A method of determining thermal diffusivity in thin plates is presented. The method, using infrared images of evolving thermal patterns previously injected with a laser, is noncontacting, one-sided, and remote. It does not require independent estimates of either the emissivity of the sample or the sample thickness. With a line-segment pattern for thermal input, it yields the in-plane components of

  17. Peripapillary choroidal thickness in childhood.

    PubMed

    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 < 0.001) and sector position (p < 0.001) in this population of children. The innermost annulus (closest to the edge of the optic disc) exhibited the thinnest choroid (mean 77 ± 16 ?m) and the outermost annulus, the thickest choroid (191 ± 52 ?m). The choroid was thinnest inferior to the optic nerve head (139 ± 38 ?m) and was thickest in the superior temporal sector (157 ± 40 ?m). 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 < 0.001). RNFL thickness also varied significantly with annulus location and sector (p < 0.001), and showed differences in 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 and choroidal thickness associated with refractive error are consistent with a redistribution of these tissues occurring with myopic axial elongation in childhood. PMID:25749004

  18. Standard methods for open hole tension testing of textile composites

    NASA Technical Reports Server (NTRS)

    Portanova, M. A.; Masters, J. E.

    1995-01-01

    Sizing effects have been investigated by comparing the open hole failure strengths of each of the four different braided architectures as a function of specimen thickness, hole diameter, and the ratio of specimen width to hole diameter. The data used to make these comparisons was primarily generated by Boeing. Direct comparisons of Boeing's results were made with experiments conducted at West Virginia University whenever possible. Indirect comparisons were made with test results for other 2-D braids and 3-D weaves tested by Boeing and Lockheed. In general, failure strength was found to decrease with increasing plate thickness, increase with decreasing hole size, and decreasing with decreasing width to diameter ratio. The interpretation of the sensitive to each of these geometrical parameters was complicated by scatter in the test data. For open hole tension testing of textile composites, the use of standard testing practices employed by industry, such as ASTM D5766 - Standard Test Method for Open Hole Tensile Strength of Polymer Matrix Composite Laminates should provide adequate results for material comparisons studies.

  19. Tectonics of the Easter plate

    NASA Technical Reports Server (NTRS)

    Engeln, J. F.; Stein, S.

    1984-01-01

    A new model for the Easter plate is presented in which rift propagation has resulted in the formation of a rigid plate between the propagating and dying ridges. The distribution of earthquakes, eleven new focal mechanisms, and existing bathymetric and magnetic data are used to describe the tectonics of this area. Both the Easter-Nazca and Easter-Pacific Euler poles are sufficiently close to the Easter plate to cause rapid changes in rates and directions of motion along the boundaries. The east and west boundaries are propagating and dying ridges; the southwest boundary is a slow-spreading ridge and the northern boundary is a complex zone of convergent and transform motion. The Easter plate may reflect the tectonics of rift propagation on a large scale, where rigid plate tectonics requires boundary reorientation. Simple schematic models to illustrate the general features and processes which occur at plates resulting from large-scale rift propagation are used.

  20. The science behind Plate Tectonics

    NSDL National Science Digital Library

    John Weber

    Plate tectonics is a quantitative, robust and testable, geologic model describing the surface motions of Earth's outer skin. It is based on real data and assumptions, and built using the scientific method. New space geodesy data provide important quantitative (and independent) tests of this model. In general, these new data show a close match to model predictions, and suggest that plate motion is steady and uniform over millions of years. Active research continues to refine the model and to better our understanding of plate motion and tectonics. The exercise presented here aims to help students experience the process of doing science and to understand the science underlying the plate tectonic theory. Key words: plate tectonics, global plate motion models, assumptions, geologic data (spreading rates, transform fault azimuths, earthquake slip vectors), space geodesy tests.

  1. Experimental technique to launch flier-plates representing orbital debris to hypervelocities

    SciTech Connect

    Chhabildas, L.C.; Boslough, M.B.

    1992-01-01

    Very high driving pressures (tens or hundreds of GPa), are required to accelerate flier plates to hypervelocities. This loading pressure pulse on the flier plates must be nearly shockless to prevent the plate from melting or vaporizing. This is accomplished by using graded-density impactors referred to as pillows.'' When this graded-density material is used to impact a flier-plate in a modified two-stage light gas gun, nearly shockless megabar pressures are introduced into the flier plate. The pressure pulses must also be tailored to prevent spallation of the flier-plate. This technique has been used to launch nominally 1-mm-thick aluminum, magnesium and titanium (gram-size) intact plates to 10.4 km/s, and 0.5-mm-thick aluminum and titanium (half-gram size) intact plates to 12.2 km/s. This is the highest mass-velocity capability attained with laboratory launchers to date, and should open up new regimes of impact physics and lethality studies related to space sciences for laboratory investigations. In particular, the mass-velocity capability of this newly developed hypervelocity launcher meets the average specifications of the space debris environment, and is therefore expected to be a useful tool to evaluate the effects of debris impact on space structures and debris shields.

  2. Experimental technique to launch flier-plates representing orbital debris to hypervelocities

    SciTech Connect

    Chhabildas, L.C.; Boslough, M.B.

    1992-12-31

    Very high driving pressures (tens or hundreds of GPa), are required to accelerate flier plates to hypervelocities. This loading pressure pulse on the flier plates must be nearly shockless to prevent the plate from melting or vaporizing. This is accomplished by using graded-density impactors referred to as ``pillows.`` When this graded-density material is used to impact a flier-plate in a modified two-stage light gas gun, nearly shockless megabar pressures are introduced into the flier plate. The pressure pulses must also be tailored to prevent spallation of the flier-plate. This technique has been used to launch nominally 1-mm-thick aluminum, magnesium and titanium (gram-size) intact plates to 10.4 km/s, and 0.5-mm-thick aluminum and titanium (half-gram size) intact plates to 12.2 km/s. This is the highest mass-velocity capability attained with laboratory launchers to date, and should open up new regimes of impact physics and lethality studies related to space sciences for laboratory investigations. In particular, the mass-velocity capability of this newly developed hypervelocity launcher meets the average specifications of the space debris environment, and is therefore expected to be a useful tool to evaluate the effects of debris impact on space structures and debris shields.

  3. Tectonic Plate Movements and Hotspots

    NSDL National Science Digital Library

    Ken Rhinehart

    This lesson introduces the idea that rates and directions of plate movements can be measured. The discussion centers on the use of mantle 'hotspots' to determine plate motions. Examples include the Hawaiian Islands, the Galapagos Islands, and the Yellowstone hotspot. The lesson includes an activity in which students use online resources to answer questions about the Galapagos Islands and measure plate movement rates using online data for the Hawaiian Islands hotspot.

  4. Ion plating for the future

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1981-01-01

    The ion plating techniques are classified relative to the instrumental set up, evaporation media and mode of transport. Distinction is drawn between the low vacuum (plasma) and high vacuum (ion beam) techniques. Ion plating technology is discussed at the fundamental and industrial level. At the fundamental level, the capabilities and limitations of the plasma (evaporant flux) and film characteristics are evaluated. On the industrial level, the performance and potential uses of ion plated films are discussed.

  5. Ion plating for the future

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1981-01-01

    The ion plating techniques are classified relative to the instrumental set up, evaporation media, and mode of transport. A distinction is drawn between the low vacuum (plasma) and high vacuum (ion beam) techniques. Ion plating technology is discussed at the fundamental and industrial level. At the fundamental level, the capabilities and limitations of the plasma (evaporant flux) and film characteristics are evaluated. And on the industrial level, the performance and potential uses of ion plated films are discussed.

  6. Global Topography and Tectonic Plates

    NSDL National Science Digital Library

    David Greene

    The goal of this activity is to investigate global topographic and tectonic features, especially the tectonic plates and their boundaries. Using a double-page size digital topographic map of the Earth that includes both land and sea floor topography, students are asked to draw plate boundaries, deduce plate motions and interactions, and explore the connections between topography and tectonic processes at the global scale.

  7. Plate T-11: Appalachian Mountains

    NSDL National Science Digital Library

    Appalachian Mountain landforms clearly demonstrate the relation of plate tectonics and structure to geomorphology. The folded rocks record the convergence of two continental plates in Pennsylvanian/Permian time. This page uses text, maps, and remotely sensed imagery to explain the relationship between plate tectonics, geologic structures, and the resulting landforms. It is part of an out-of-print NASA publication entitled 'Geomorphology from Space'. Links to the rest of the book are provided.

  8. High accuracy wall thickness loss monitoring

    NASA Astrophysics Data System (ADS)

    Gajdacsi, Attila; Cegla, Frederic

    2014-02-01

    Ultrasonic inspection of wall thickness in pipes is a standard technique applied widely in the petrochemical industry. The potential precision of repeat measurements with permanently installed ultrasonic sensors however significantly surpasses that of handheld sensors as uncertainties associated with coupling fluids and positional offsets are eliminated. With permanently installed sensors the precise evaluation of very small wall loss rates becomes feasible in a matter of hours. The improved accuracy and speed of wall loss rate measurements can be used to evaluate and develop more effective mitigation strategies. This paper presents an overview of factors causing variability in the ultrasonic measurements which are then systematically addressed and an experimental setup with the best achievable stability based on these considerations is presented. In the experimental setup galvanic corrosion is used to induce predictable and very small wall thickness loss. Furthermore, it is shown that the experimental measurements can be used to assess the effect of reduced wall loss that is produced by the injection of corrosion inhibitor. The measurements show an estimated standard deviation of about 20nm, which in turn allows us to evaluate the effect and behaviour of corrosion inhibitors within less than an hour.

  9. Three-dimensional (3-D) model of electric field and space charge in the barbed plate-to-plate precipitator

    SciTech Connect

    Davidson, J.H.; McKinney, P.J. [Univ. of Minnesota, Minneapolis, MN (United States)] [Univ. of Minnesota, Minneapolis, MN (United States); Linnebur, P. [Coors Ceramic Co., Golden, CO (United States)] [Coors Ceramic Co., Golden, CO (United States)

    1996-07-01

    A finite-element/method-of-characteristics model of three-dimensional (3-D) electrode geometries with corona discharge is used to predict space charge density, current density, electric potential and electric field in point-to-plane, single-barb plate-to-plane, and hexagonal multiple-barbed plate-to-plate geometries. Although a modification of Peek`s formula for the hyperboid-to-plane was initially used to establish a boundary condition at the edge of the corona, predicted total current did not agree with measured values. As a result, it was necessary to use measured current-voltage characteristics to establish the space charge density at the outer surface of the corona sheath. An additional problem in modeling point discharges is specification of shape and size of the corona sheath. Both the authors` results and much earlier work by Trichel suggest that the thickness of the corona sheath cannot be automatically neglected.

  10. License Plates of the World

    NSDL National Science Digital Library

    Whether you're interested in collecting license plates, or are just moving to Andorra and wonder what your car will be wearing when it gets there, this site provided by collector Michael Kustermann can be a handy reference. A winner in the "labor of love" website category, this frames-based directory contains pictures of and descriptive information about a dizzying range of automobile license plates, arranged geographically. Special issue and commemorative plates are also covered, as well as links to collector's clubs and a bibliography about the art and science of license plate hunting and gathering. You'll never look at bumpers quite the same way.

  11. Carbon-assisted flyer plates

    DOEpatents

    Stahl, David B. (Los Alamos, NM); Paisley, Dennis L. (Santa Fe, NM)

    1994-01-01

    A laser driven flyer plate utilizing an optical fiber connected to a laser. The end of the optical fiber has a layer of carbon and a metal layer deposited onto it. The carbon layer provides the laser induced plasma which is superior to the plasma produced from most metals. The carbon layer plasma is capable of providing a flatter flyer plate, converting more of the laser energy to driving plasma, promoting a higher flyer plate acceleration, and providing a more uniform pulse behind the plate. In another embodiment, the laser is in optical communication with a substrate onto which a layer of carbon and a layer of metal have been deposited.

  12. The Nature of Tectonic Plates

    NSDL National Science Digital Library

    2008-12-30

    This lesson provides an overview of the various types of interactions between tectonic plates. The discussion uses the analogy of a cracked egg to describe the tectonic plates composing Earth's crust. Other topics include the concentrated earthquake and volcanic activity associated with plate boundaries, types of interactions at the boundaries, and how plate motions are affecting the Atlantic and Pacific Oceans. The lesson includes an activity in which students will use online references to locate a hypothetical nuclear power plant in a geologically safe area, investigate the history of large earthquakes in South Carolina, provide a likely location for a hypothetical geothermal power plant, and others.

  13. Laser-driven flyer plate

    DOEpatents

    Paisley, Dennis L. (Santa Fe, NM)

    1991-01-01

    Apparatus for producing high velocity flyer plates involving placing a layer of dielectric material between a first metal foil and a second metal foil. With laser irradiation through an optical substrate, the first metal foil forms a plasma in the area of the irradiation, between the substrate and the solid portion of the first metal foil. When the pressure between the substrate and the foil reaches the stress limit of the dielectric, the dielectric will break away and launch the flyer plate out of the second metal foil. The mass of the flyer plate is controlled, as no portion of the flyer plate is transformed into a plasma.

  14. True Shear Parallel Plate Viscometer

    NASA Technical Reports Server (NTRS)

    Ethridge, Edwin; Kaukler, William

    2010-01-01

    This viscometer (which can also be used as a rheometer) is designed for use with liquids over a large temperature range. The device consists of horizontally disposed, similarly sized, parallel plates with a precisely known gap. The lower plate is driven laterally with a motor to apply shear to the liquid in the gap. The upper plate is freely suspended from a double-arm pendulum with a sufficiently long radius to reduce height variations during the swing to negligible levels. A sensitive load cell measures the shear force applied by the liquid to the upper plate. Viscosity is measured by taking the ratio of shear stress to shear rate.

  15. Effect of Pressure Gradients on Plate Response and Radiation in a Supersonic Turbulent Boundary Layer

    NASA Technical Reports Server (NTRS)

    Frendi, Abdelkader

    1997-01-01

    Using the model developed by the author for zero-pressure gradient turbulent boundary layers, results are obtained for adverse and favorable pressure gradients. It is shown that when a flexible plate is located in an adverse pressure gradient area, it vibrates more than if it were in a favorable pressure gradient one. Therefore the noise generated by the plate in an adverse pressure gradient is much greater than that due to the plate in a favorable pressure gradient. The effects of Reynolds number and boundary layer thickness are also analyzed and found to have the same effect in both adverse and favorable pressure gradient cases. Increasing the Reynolds number is found to increase the loading on the plate and therefore acoustic radiation. An increase in boundary layer thickness is found to decrease the level of the high frequencies and therefore the response and radiation at these frequencies. The results are in good qualitative agreement with experimental measurements.

  16. Design and construction of a guarded hot plate apparatus operating down to liquid nitrogen temperature

    NASA Astrophysics Data System (ADS)

    Li, Manfeng; Zhang, Hua; Ju, Yonglin

    2012-07-01

    A double-sided guarded hot plate apparatus (GHP) is specifically designed, fabricated, and constructed for the measurement of thermal conductivities of insulation specimens operated down to liquid nitrogen temperature (-196 °C), at different controlled pressures from 0.005 Pa to 0.105 MPa. The specimens placed in this apparatus are 300 mm in diameter at various thicknesses ranging from 4 mm to 40 mm. The apparatus is different from traditional GHP in terms of structure, supporting and heating method. The details of the design and construction of the hot plate, the cold plates, the suspensions, the clampings, and the vacuum chamber of the system are presented. The measurement methods of the temperatures, the input power, the meter area, and the thickness of the specimens are given. The apparatus is calibrated with teflon plates as sample and the maximum deviation from the published data is about 6% for thermal conductivity. The uncertainties for the measurement are also discussed in this paper.

  17. Measurements of displacement around holes in composite plates subjected to quasi-static compression

    NASA Technical Reports Server (NTRS)

    Duke, J. C., Jr.; Post, D.; Czarnek, R.; Asundi, A.

    1982-01-01

    Attempts to develop a whole-field, high sensitivity optical technque for measurement of load induced changes of thickness of composite plates are described. Graphite-epoxy plates of quasi-isotropic layup were used as test specimens. Changes of thickness of three plates, each with a central hole of different size, were measured as a function of applied compressive loads. The first test specimen showed localized zones where no holographic fringes were present, surrounded by zones of low fringe contrast. This was thought to be a result of localized motion or creep. Subsequent tests with an increased time interval between specimen loading and holographic exposure demonstrated no localized zones of absent fringes. No plausible explanation for radical differences in the quality of fringe patterns was found, although the use of specimens having a high quality mirrorized surface provided superior change of thickness patterns. Recommendations for further investigations and changes in test procedure are presented.

  18. Thin film/substrate systems featuring arbitrary film thickness and misfit strain distributions. Part I: Analysis

    E-print Network

    Rosakis, Ares J.

    curvature measurements are strictly restricted to stress and curvature states which are assumed to remain. Introduction Stoney (1909) used a plate system composed of a stress bearing thin film, of uniform thickness hf used in the literature to infer film stress changes from experimental measurement of system curvature

  19. Inverse modelling of elastic thickness by convolution method – the eastern Alps as a case example

    Microsoft Academic Search

    Carla Braitenberg; Jörg Ebbing; Hans-Jürgen Götze

    2002-01-01

    An unconventional scheme is used to estimate the flexural rigidity, or equivalently the elastic thickness of the lithosphere, given the topography and gravity data. The flexural rigidity is the parameter that governs the flexural response of the lithosphere in the frame of the thin plate flexure model. The scheme is an alternative to the widely used calculation of admittance of

  20. Analysis of tongue and groove joints for thick laminatesq Karel Matous, George J. Dvorak*

    E-print Network

    Matous, Karel

    evaluation of local stresses in the adhesive and adherends is presented for a tongue-and-groove joint of a homogenized thick composite laminate to steel plate. The quasi-isotropic laminate is made of glass fabric/vinyl ester plies. Most results are obtained for elastic response of the Dexter-Hysol 9338 adhesive