Science.gov

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. 49 CFR 179.100-6 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... thickness after forming of the tank shell and heads must not be less than that specified in § 179.101, nor....; S = Minimum tensile strength of plate material in p.s.i., as prescribed in § 179.100-7; t = Minimum thickness of plate in inches after forming. (b) If plates are clad with material having tensile...

  3. 49 CFR 179.200-6 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... thickness after forming of the tank shell, dome shell, and of 2:1 ellipsoidal heads must be not less than... bursting pressure in psig; S = Minimum tensile strength of plate material in p.s.i. as prescribed in § 179.200-7; t = Minimum thickness of plate in inches after forming. (b) The wall thickness after forming...

  4. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... (a) The minimum wall thickness, after forming, of the inner shell and any 2:1 ellipsoidal head for..., whichever is greater: t = Pd / 2SE Where: t = minimum thickness of plate, after forming, in inches; P... of the plate material, as prescribed in AAR Specifications for Tank Cars, appendix M, Table M1...

  5. Design of a Variable Thickness Plate to Focus Bending Waves

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Lin, Sz-Chin Steven; Cabell, Randolph H.; Huang, Tony Jun

    2012-01-01

    This paper describes the design of a thin plate whose thickness is tailored in order to focus bending waves to a desired location on the plate. Focusing is achieved by smoothly varying the thickness of the plate to create a type of lens, which focuses structural-borne energy. Damping treatment can then be positioned at the focal point to efficiently dissipate energy with a minimum amount of treatment. Numerical simulations of both bounded and unbounded plates show that the design is effective over a broad frequency range, focusing traveling waves to the same region of the plate regardless of frequency. This paper also quantifies the additional energy dissipated by local damping treatment installed on a variable thickness plate relative to a uniform plate.

  6. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-8 Thickness of plates. (a) The minimum wall thickness, after forming, of the inner shell and any 2:1...; P = minimum required bursting pressure in psig; L = main inside radius of dished head, in inches; r... the outer jacket shell may not be less than 7/16 inch. The minimum wall thickness, after forming,...

  7. Thickness dependence of the Casimir force between a magnetodielectric plate and a diamagnetic plate

    SciTech Connect

    Inui, Norio

    2011-11-15

    This paper examines the repulsive Casimir force between a magnetodielectric plate, with static permeability greater than static permittivity, and a diamagnetic plate. As the thickness of the magnetodielectric plate is decreased, the attractive component of the Casimir force decreases more than the repulsive one. This effect makes the net Casimir force repulsive, and a larger repulsive Casimir force is generated compared to the Casimir force between the plates with infinite thickness.

  8. 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.

  9. Thick plate flexure. [for lithospheric models of Mars and earth

    NASA Technical Reports Server (NTRS)

    Comer, R. P.

    1983-01-01

    Analytical expressions are derived for the displacements and stresses due to loading of a floating, uniform, elastic plate of arbitrary thickness by a plane or axisymmetric harmonic load. The solution is exact except for assumptions of small strains and linear boundary conditions, and gravitation within the plate is neglected. For typical earth parameters its predictions are comparable to those of the usual thin plate theory frequently assumed in studies of lithospheric flexure, gravity and regional isostasy. Even for a very thick lithosphere, which may exist in some regions of Mars, the thin plate theory is a better approximation to the thick plate solution than the elastic half-space limit, except for short-wavelength loads.

  10. 49 CFR 179.220-6 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... of the outer shell must be not less than seven-sixteenths of an inch. (d) See § 179.220-9 for plate... thickness, after forming of the inner container shell and 2:1 ellipsoidal heads must be not less than... required bursting pressure in psig; S = Minimum tensile strength of plate material in p.s.i. as...

  11. Modes of vibration on sqaure fiberglass epoxy composite thick plate

    NASA Technical Reports Server (NTRS)

    Williams, J. H., Jr.; Marques, E. R. C.; Lee, S. S.

    1986-01-01

    The frequencies and nodal patterns of a square thick plate of unidirectional fiberglass epoxy composite are measured experimentally. The constituent material is transversely isotropic. The plate is transversely excited at the center of the upper face, its resonant frequencies in the frequency range of 3 kHz to 21.73 kHz are detected and the measured nodal patterns are sketched.

  12. Stress measurement in thick plates using nonlinear ultrasonics

    SciTech Connect

    Abbasi, Zeynab E-mail: dozevin@uic.edu; Ozevin, Didem E-mail: dozevin@uic.edu

    2015-03-31

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

  13. An Analysis of Thickness-shear Vibrations of an Annular Plate with the Mindlin Plate Equations

    E-print Network

    Wang, Ji; Ma, Tingfeng; Du, Jianke; Yi, Lijun; Yong, Yook-Kong

    2015-01-01

    The Mindlin plate equations with the consideration of thickness-shear deformation as an independent variable have been used for the analysis of vibrations of quartz crystal resonators of both rectangular and circular types. The Mindlin or Lee plate theories that treat thickness-shear deformation as an independent higher-order vibration mode in a coupled system of two-dimensional variables are the choice of theory for analysis. For circular plates, we derived the Mindlin plate equations in a systematic manner as demonstrated by Mindlin and others and obtained the truncated two-dimensional equations of closely coupled modes in polar coordinates. We simplified the equations for vibration modes in the vicinity of fundamental thickness-shear frequency and validated the equations and method. To explore newer structures of quartz crystal resonators, we utilized the Mindlin plate equations for the analysis of annular plates with fixed inner and free outer edges for frequency spectra. The detailed analysis of vibratio...

  14. 49 CFR 179.100-6 - Thickness of plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Thickness of plates. 179.100-6 Section 179.100-6 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks...

  15. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Thickness of plates. 179.400-8 Section 179.400-8 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for...

  16. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Thickness of plates. 179.400-8 Section 179.400-8 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for...

  17. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Thickness of plates. 179.400-8 Section 179.400-8 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for...

  18. Residual stress determination in thick welded steel plates

    NASA Astrophysics Data System (ADS)

    Em, Vyacheslav; Woo, Wanchuck; Seong, Baek-Seok; Mikula, Pavol; Joo, Jongdae; Kang, Mi-Hyun; Lee, Kyu Hong

    2012-02-01

    Through thickness strain distribution of 50 mm thick welded ferritic steel (bcc) plate was studied using diffraction reflections 211 and 110 and neutron wavelengths of 1.55 and 2.39Å, respectively. Experimental results showed that for stress measurements in a possibly maximum thick weld, the different strain components should be measured with different reflections 211 and 110. The strains measured with these reflections for the same component are close. Since planes (211) and (110) of bcc ferrite have the same diffraction elastic constants the appropriate values of stresses could be derived from strains measured with reflections 211 and 110.

  19. Thickness vibrations of a piezoelectric plate with dissipation.

    PubMed

    Lee, Peter C Y; Liu, Ninghui; Ballato, Arthur

    2004-01-01

    The three-dimensional (3-D) equations of linear piezoelectricity with quasi-electrostatic approximation are extended to include losses attributed to the acoustic viscosity and electrical conductivity. These equations are used to investigate effects of dissipation on the propagation of plane waves in an infinite solid and forced thickness vibrations in an infinite piezoelectric plate with general symmetry. For a harmonic plane wave propagating in an arbitrary direction in an unbounded solid, the complex eigenvalue problem is solved from which the effective elastic stiffness, viscosity, and conductivity are computed. For the forced thickness vibrations of an infinite plate, the complex coupling factor K*, input admittance Y are derived and an explicit, approximate expression for K* is obtained in terms of material properties. Effects of the viscosity and conductivity on the resonance frequency, modes, admittance, attenuation coefficient, dynamic time constant, coupling factor, and quality factor are calculated and examined for quartz and ceramic barium titanate plates. PMID:14995016

  20. 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.

  1. Relation between subduction megathrust earthquakes, trench sediment thickness and upper plate strain

    E-print Network

    Conrad, Clint

    Relation between subduction megathrust earthquakes, trench sediment thickness and upper plate, by compiling a dataset of trench fill thickness (a proxy for smoothing of subducting plate relief by sediment relationships between upper plate strain, trench sediment thickness and maximal earthquake magnitude. We find

  2. 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.

  3. 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.

  4. Integrated crustal thickness mapping and plate reconstructions for the high Arctic A. Alvey a,

    E-print Network

    Torsvik, Trond Helge

    Integrated crustal thickness mapping and plate reconstructions for the high Arctic A. Alvey a, , C of Liverpool, Liverpool, L69 3GP, UK b Centre for Geodynamics, Geological Survey of Norway, Leiv Eirikssons vei Editor: C.P. Jaupart Keywords: Arctic Ocean plate reconstructions gravity inversion crustal thickness

  5. Relation between subduction megathrust earthquakes, trench sediment thickness and upper plate strain

    E-print Network

    Conrad, Clint

    Relation between subduction megathrust earthquakes, trench sediment thickness and upper plate of sediment thickness at trench We constrained sediment thickness at the trench (Tsed), and its lateral variability, for 44 trench sections (Figure 1) based on a compilation of published local seismic

  6. General analytical approach for sound transmission loss analysis through a thick metamaterial plate

    SciTech Connect

    Oudich, Mourad; Zhou, Xiaoming; Badreddine Assouar, M.

    2014-11-21

    We report theoretically and numerically on the sound transmission loss performance through a thick plate-type acoustic metamaterial made of spring-mass resonators attached to the surface of a homogeneous elastic plate. Two general analytical approaches based on plane wave expansion were developed to calculate both the sound transmission loss through the metamaterial plate (thick and thin) and its band structure. The first one can be applied to thick plate systems to study the sound transmission for any normal or oblique incident sound pressure. The second approach gives the metamaterial dispersion behavior to describe the vibrational motions of the plate, which helps to understand the physics behind sound radiation through air by the structure. Computed results show that high sound transmission loss up to 72?dB at 2?kHz is reached with a thick metamaterial plate while only 23?dB can be obtained for a simple homogeneous plate with the same thickness. Such plate-type acoustic metamaterial can be a very effective solution for high performance sound insulation and structural vibration shielding in the very low-frequency range.

  7. New approach to the excitation of plate waves for piezoelectric thick-film devices.

    PubMed

    De Cicco, Giorgio; Morten, Bruno

    2008-12-01

    A method is presented for exciting the propagation of plate waves in elastic guides. It is implemented in a device whose minimum working structure consists of a non-piezoelectric plane guide and two piezoelectric transducers operating as a generator and detector. The device is entirely in accordance with thick-film technology standard procedures. Both transducers are composed of a PZT ferroelectric layer deposited on a ceramic substrate and a suitable system of three coplanar metal electrodes placed inside the same layer. Beside setting the wavelength of propagation, the electrode system promotes piezoelectric deformations parallel to the substrate simultaneously contracting and extending contiguous active regions in the layer. Pure shear stresses are then induced on the involved guide surface, alternately distributed, with the spatial periodicity of the wave that will propagate in the guide. The propagation of several kinds of guided waves is possible so the selection of the one that meets a specific device design best is allowed. This work describes the design, realization and operation of a prototype structure consisting of an alumina plate guide and two pairs of piezoelectric thick-film transducers realized on it. The results related to the propagation of symmetric and asymmetric Lamb modes are reported. Moreover, the potential of the method is highlighted, emphasizing its effectiveness, easy implementation and application in the development of devices for the sensing and non-destructive testing areas. PMID:18486958

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

    NASA Astrophysics Data System (ADS)

    Serizawa, Hisashi; Nakamura, Shinichiro; Tanaka, Manabu; Kawahito, Yousuke; Tanigawa, Hiroyasu; Katayama, Seiji

    2011-10-01

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

  9. 49 CFR 179.200-6 - Thickness of plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...bring the entire width of the longitudinal welded joint, including welds, above the bolster. (f) For a tank built of one piece cylindrical sections, the thickness specified for bottom sheet must apply to the entire cylindrical section....

  10. 49 CFR 179.200-6 - Thickness of plates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...bring the entire width of the longitudinal welded joint, including welds, above the bolster. (f) For a tank built of one piece cylindrical sections, the thickness specified for bottom sheet must apply to the entire cylindrical section....

  11. 49 CFR 179.200-6 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...bring the entire width of the longitudinal welded joint, including welds, above the bolster. (f) For a tank built of one piece cylindrical sections, the thickness specified for bottom sheet must apply to the entire cylindrical section....

  12. 49 CFR 179.200-6 - Thickness of plates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...bring the entire width of the longitudinal welded joint, including welds, above the bolster. (f) For a tank built of one piece cylindrical sections, the thickness specified for bottom sheet must apply to the entire cylindrical section....

  13. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...45(t/D)0.5 ] Where: Pc = Critical collapsing pressure (37.5 psig minimum) in psig; E = modulus of elasticity of jacket material, in psi; t = minimum thickness of jacket material, after forming, in inches; D = outside...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...45(t/D)0.5 ] Where: Pc = Critical collapsing pressure (37.5 psig minimum) in psig; E = modulus of elasticity of jacket material, in psi; t = minimum thickness of jacket material, after forming, in inches; D = outside...

  15. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...45(t/D)0.5 ] Where: Pc = Critical collapsing pressure (37.5 psig minimum) in psig; E = modulus of elasticity of jacket material, in psi; t = minimum thickness of jacket material, after forming, in inches; D = outside...

  16. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...45(t/D)0.5 ] Where: Pc = Critical collapsing pressure (37.5 psig minimum) in psig; E = modulus of elasticity of jacket material, in psi; t = minimum thickness of jacket material, after forming, in inches; D = outside...

  17. 49 CFR 179.400-8 - Thickness of plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...45(t/D)0.5 ] Where: Pc = Critical collapsing pressure (37.5 psig minimum) in psig; E = modulus of elasticity of jacket material, in psi; t = minimum thickness of jacket material, after forming, in inches; D = outside...

  18. A solution procedure for behavior of thick plates on a nonlinear foundation and postbuckling behavior of long plates

    NASA Technical Reports Server (NTRS)

    Stein, M.; Stein, P. A.

    1978-01-01

    Approximate solutions for three nonlinear orthotropic plate problems are presented: (1) a thick plate attached to a pad having nonlinear material properties which, in turn, is attached to a substructure which is then deformed; (2) a long plate loaded in inplane longitudinal compression beyond its buckling load; and (3) a long plate loaded in inplane shear beyond its buckling load. For all three problems, the two dimensional plate equations are reduced to one dimensional equations in the y-direction by using a one dimensional trigonometric approximation in the x-direction. Each problem uses different trigonometric terms. Solutions are obtained using an existing algorithm for simultaneous, first order, nonlinear, ordinary differential equations subject to two point boundary conditions. Ordinary differential equations are derived to determine the variable coefficients of the trigonometric terms.

  19. The displacement field in the vibration analysis of laminated thick plates

    SciTech Connect

    Ohta, Yoshiki; Narita, Yoshihiro

    1995-11-01

    The present paper discusses the assumption of displacement fields used in the vibration analysis of FRP laminated thick plates. For this purpose, the strain and kinetic energies of a FRP cross-ply laminated plate are evaluated analytically based on the three-dimensional theory of elasticity, and the displacements of the rectangular plate, which are simply-supported at all edges, are expanded into the polynomial forms with respect to thickness coordinate. A frequency equation is formulated by using the energy method minimizing the Lagrange function. In the numerical calculations, natural frequencies are obtained for the plates with various stacking sequence and the thickness ratios, and the validity of the assumption of displacement fields and the range of applicability of the various plate theories (e.g. the Classical Plate Theory (CPT), the First-Order Shear Deformation Theory (FSDT) and the Higher-Order Shear Deformation Theory (HSDT)), which are widely used in the vibration analysis of FRP laminated plates, to the laminated thick plates are discussed by comparing the present results with the CPT and the FSDT solutions.

  20. 49 CFR 179.220-6 - Thickness of plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) The wall thickness, after forming of the inner container shell and 2:1 ellipsoidal heads must be not... seamless heads; L = Main inside radius to which head is dished, measured on concave side in inches; P... cylindrical section and heads of the outer shell must be not less than seven-sixteenths of an inch. (d)...

  1. Thickness vibration of piezoelectric plates of 6mm crystals with tilted six-fold axis and two-layered thick electrodes.

    PubMed

    Du, Jianke; Xian, Kai; Wang, Ji; Yang, Jiashi

    2009-02-01

    We perform a theoretical analysis of thickness vibrations in piezoelectric plates of crystals with 6mm symmetry. The six-fold axis is tilted with respect to the plate surfaces. The major surfaces of the plate are covered with two layers of electrodes of different metals. The equations of linear piezoelectricity are used for the crystal plate. The electrodes are modeled by the equations of elasticity. Thickness vibrations frequencies and modes as well as impedance are calculated and examined. PMID:18951601

  2. 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.

  3. Effect of vibratory stress relief during welding of thick stainless steel plate

    NASA Astrophysics Data System (ADS)

    Spooner, S.; David, S. A.; Wang, X. L.; Hubbard, C. R.; Holden, T. M.; Root, J. H.

    1993-12-01

    Residual strains were measured in two welded 25-mm thick plates of type 304 stainless steel by the neutron diffraction technique. The filler metal employed to weld these plates was type 308 stainless steel. One of the two welds was prepared without any vibratory stress relief treatment and the other was vibrated at a frequency below the resonant condition which gives a fraction the resonant amplitude during welding. In both plates the largest residual stress component found in the heat affected zone and in the base metal is along the fusion joint (longitudinal) and is found at the boundary between the weld zone and the heat affected zone. This longitudinal component is 300 +/- 50 MPa in tension. The associated normal stress was close to zero and the transverse stress was 80 +/- 50 MPa. Variations in residual stresses with thickness through the base metal plate were small. The treated plate and untreated plate showed nearly identical patterns of stress distribution. Differences in the measured stresses between the vibratory-stress-relief treated and the untreated plates fall within the error bars of the stress determination in these particular 25 mm thick 300-type stainless steel plates.

  4. Thickness effects on the plastic collapse of perforated plates with triangular penetration patterns

    SciTech Connect

    Gordon, J.L.; Jones, D.P.; Holliday, J.E.

    2000-03-01

    This paper investigates the effects of plate thickness on the accuracy of limit load solutions obtained using an elastic-perfectly plastic [EPP] equivalent solid [EQS] procedure for flat perforated plates with a triangular array of penetrations. The EQS approach for limit loads is based on an EQS collapse surface that is valid for generalized plane strain. This assumption is applicable for very thick plates but is known to be less reasonable for very thin plates where plane stress may be a better assumption. The limits of applicability of the generalized plane strain assumption are investigated by obtaining limit load solutions for perforated plates of various thicknesses that are subjected to in-plane and bending loads. Plastic limit load solutions obtained using three-dimensional EPP finite element analysis [FEA] of models which include each penetration explicitly are compared with solutions obtained using the EQS approximation. The penetration pattern chosen for this study has a ligament efficiency (ligament width-to-pitch ratio, h/P) of 0.32. For plates thicker than the pitch, the limit load calculated using the EQS method for both in-plane and bending loads is shown to be very accurate (within 4%) of the limit load calculated for the explicit model. On the other hand, for thin plates (t/P< 2), the EQS limit load is 5% greater than the explicit limit load for bending and 8% greater than the explicit limit load for in-plane loads. For thinner plates, the collapse surface is tied to the local geometry deformation and, hence, an equivalent solid plate representation of plastic collapse is a function of deformation mode and thickness.

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

    NASA Technical Reports Server (NTRS)

    Smith, Barry T.; Farley, Gary L.; Maiden, Janice; Coogan, Dreux; Moore, Judith G.

    1991-01-01

    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 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.

  6. 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.

  7. 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.

  8. Effect of geometric nonlinearity on the free flexural vibrations of moderately thick rectangular plates

    NASA Technical Reports Server (NTRS)

    Raju, K. K.; Rao, G. V.; Raju, I. S.

    1978-01-01

    The effect of geometric nonlinearity on the free flexural vibrations of moderately thick rectangular plates is studied in this paper. Finite element formulation is employed to obtain the non-linear to linear period ratios for some rectangular plates. A conforming finite element of rectangular shape wherein the effects of shear deformation and rotatory inertia are included, is developed and used for the analysis. Results are presented for both simply supported and clamped boundary conditions.

  9. Simultaneous measurement of refractive index and thickness of birefringent wave plates

    SciTech Connect

    Yeh, Y.-L

    2008-04-01

    A nondestructive measurement system based on a position sensing detector (PSD) and a laser interferometer for determining the thickness and refractive indices of birefringent optical wave plates has been developed. Unlike previous methods presented in the literature, the proposed metrology system allows the refractive index and thickness properties of the optical plate to be measured simultaneously. The experimental results obtained for the e-light and o-light refractive indices of a commercially available birefringent optical wave plate with refractive indices of no=1.542972 and ne=1.552033 are found to be accurate to within 0.004132 and 0.000229, respectively. Furthermore, the experimentally derived value of the wave plate thickness deviates by no more than 0.9 {mu}m from the analytically derived value of 453.95 {mu}m. Overall, the experimental results confirm that the proposed metrology system provides a simple yet highly accurate means of obtaining simultaneous measurements of the refractive indices and thickness of birefringent optical wave plates.

  10. A variable kinematic Ritz formulation for vibration study of quadrilateral plates with arbitrary thickness

    NASA Astrophysics Data System (ADS)

    Dozio, Lorenzo; Carrera, Erasmo

    2011-08-01

    A new variable kinematic Ritz method applied to free vibration analysis of arbitrary quadrilateral thin and thick isotropic plates is presented. Carrera's unified formulation and the versatile pb-2 Ritz method are properly combined to build a powerful yet simple modeling and solution framework. The proposed technique allows to generate arbitrarily accurate Ritz solutions from a large variety of refined two-dimensional plate theories by expanding so-called Ritz fundamental nuclei of the plate mass and stiffness matrices. Theoretical development of the present methodology is described in detail. Convergence and accuracy of the method are examined through several examples on thin, moderately thick, and very thick plates of rectangular, skew, trapezoidal and general quadrilateral shapes, with an arbitrary combination of clamped, free and simply supported edges. Present results are compared with existing three-dimensional solutions from open literature. Maximum and average differences of various higher-order plate theories and three-dimensional results are also presented with the aim of providing useful guidelines on the choice of appropriate plate theory to get a desired accuracy on frequency parameters.

  11. The effect of damping layers on vibration of laminated thick plates

    SciTech Connect

    Ohta, Yoshiki; Narita, Yoshihiro

    1995-11-01

    This paper deals with the effect of damping layers on vibration characteristics of cross-ply laminated, fiber reinforced plastics (FRP) thick plates with damping interleaves. For this purpose, the laminated plates are modeled by using the Multi-Layer (Individual-Layer) Theory. In this theory, a coordinate system is individually taken in each FRP layer or damping layer, and in-plane and out-of-plane displacements are assumed in the polynomial forms of third and second order, respectively. A set of governing equations for the whole laminated plate is derived from the equations of motion and other interfacial conditions. The free vibration and steady state vibration problems of the laminated plate are thus solved by the multi-layer theory. For comparison, an analysis is also presented by using the Lamination Theory, which uses only a single displacement field for the whole plate. Natural frequencies and steady state responses are calculated in numerical examples for the plates with various stacking sequence and thickness ratios of damping layers to FRP layers, and the effects of location and thickness of the damping layers on vibration characteristics are studied. Furthermore, the applicability of both the multi-layer and the lamination theories in the vibration analysis is discussed by comparing two sets of results.

  12. Thick plate bending wave transmission using a mobility power flow approach

    NASA Technical Reports Server (NTRS)

    Mccollum, M. D.; Cuschieri, J. M.

    1990-01-01

    The mobility power flow (MPF) approach is used in this paper to describe the flexural behavior of an L-shaped plate structure consisting of thick plates with rotary inertia and shear deformation effects included in the analysis. The introduction of the thick plate effects significantly increases the complexity of the structural mobility functions used in the definitions of the power flow terms; however, because of the substructuring that is used in the MPF approach, the complexity of the problem is significantly reduced as compared to solving for the global structure. Additionally, with the MPF approach the modal behavior is described. The MPF analysis of the L-shaped plate is performed for the case of point force excitation on one plate, with the two plates being identical in both size and thickness. The results of this analysis are compared to results from the finite-element analysis (FEA) and the statistical energy analysis (SEA) and show very good agreement in the low- and high-frequency regimes, respectively.

  13. 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.

  14. Relation between subduction megathrust earthquakes, sediment thickness at trench, and plate coupling

    NASA Astrophysics Data System (ADS)

    Heuret, A.; Conrad, C. P.; Funiciello, F.; Lallemand, S.

    2011-12-01

    Extreme seismic events (Mw 8.5 and higher) are uniformly characterized by trench-parallel rupture lengths longer than about 250 km, whereas downdip rupture width ranges from less than 70 km (e.g., Central Aleutians) to more than 200 km (e.g., Andaman-Sumatra). The ability of rupture to propagate in the trench-parallel direction thus appears to play a fundamental role in determining the potential magnitude that an earthquake can achieve for a given subduction zone. The rupture length may be influenced by the nature of the plate interface and the normal stresses applied to the plate interface (plate coupling). The nature of the plate interface is potentially modified by sediment subduction. Subduction of a thick section of trench sediment constructs a laterally homogenous layer between upper and lower plates that smoothes subducted sea-floor relief and strength-coupling asperities (Ruff, 1989). Such a homogeneous interface running parallel to the subduction zone tends to favor long trench-parallel propagation of rupture, and thus large earthquake magnitudes. Compressive normal stresses applied along the plate interface may also tune the earthquake magnitude potential (Ruff & Kanamori, 1980). This plate coupling across the subducting interface can be indirectly estimated by Upper Plate Strain analysis, by using the back-arc as a strain sensor from which we can infer the back-arc stress state. Compressive back-arcs indicate that large stresses are transmitted across the plate interface whereas extensional settings indicate weak plate coupling. Here we present the results of a study funded by the European Science Foundation - EURYI project titled "Convergent margin and seismogenesis". Maximal earthquake magnitude, sediment thickness at the trench and Upper Plate Strain are characterized for worldwide subduction zones in order to test how plate coupling and sediment thickness combine to explain the occurrence of mega-events at the subduction interface. Subduction zones are described through an initial set of 505 transects, systematically extracted each 1° of trench, and merged into 62 subduction segments of homogeneous seismogenetic conditions. Maximal earthquake magnitude has been estimated by combining instrumental and historical seismicity. Trench sediment thickness has been constrained for 48 subduction segments; based on a compilation of 165 different seismic-reflection lines (33% of the initial set of transects).

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

    SciTech Connect

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

    2011-07-20

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

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

    NASA Astrophysics Data System (ADS)

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

    2001-12-01

    Seismic and thermal estimates suggest a highly variable thickness of Precambrian lithosphere (140-350 km), with a bimodal distribution for Archean cratons ( ~ 220 km and ~ 350 km). We discuss the origin of such large variations in lithospheric thickness and examine mechanisms of lithospheric erosion. Our analysis shows that the horizontal and vertical dimensions of Archean cratons are strongly correlated: larger cratons have thicker lithosphere. The basal drag model of lithosphere erosion (Sleep, 2001) is tested as a means of explaining the present-day bimodal distribution of lithospheric thicknesses of the Archean cratons. In agreement with theoretical predictions, we find that lithospheric thickness in 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. These results show that the basal drag model provides a viable explanation for the variation in thickness of Archean cratonic roots. 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.

  17. Numerical Investigation of Residual Stress in Thick Titanium Alloy Plate Joined with Electron Beam Welding

    NASA Astrophysics Data System (ADS)

    Liu, Chuan; Wu, Bing; Zhang, Jian Xun

    2010-10-01

    A finite-element (FE) simulation process integrating three dimensional (3D) with two-dimensional (2D) models is introduced to investigate the residual stress of a thick plate with 50-mm thickness welded by an electron beam. A combined heat source is developed by superimposing a conical volume heat source and a uniform surface heat source to simulate the temperature field of the 2D model with a fine mesh, and then the optimal heat source parameters are employed by the elongated heat source for the 3D simulation without trial simulations. The welding residual stress also is investigated with emphasis on the through-thickness stress for the thick plate. Results show that the agreement between simulation and experiment is good with a reasonable degree of accuracy in respect to the residual stress on the top surface and the weld profile. The through-thickness residual stress of the thick plate induced by electron beam welding is distinctly different from that of the arc welding presented in the references.

  18. 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.

  19. 46 CFR 32.59-1 - Minimum section modulus and plating thickness requirements-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... I oil cargo listed in 46 CFR Table 30.25-1. (c) For all vessels except those limited on their Certificate of Inspection to river routes only, the minimum midship section modulus must be— (1) At least 90... and plating thickness requirements—TB/ALL. (a) As used in this section, Rule means the current...

  20. 46 CFR 32.59-1 - Minimum section modulus and plating thickness requirements-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... I oil cargo listed in 46 CFR Table 30.25-1. (c) For all vessels except those limited on their Certificate of Inspection to river routes only, the minimum midship section modulus must be— (1) At least 90... and plating thickness requirements—TB/ALL. (a) As used in this section, Rule means the current...

  1. Large-area full-field thickness measurement of glass plates by an optical interferometric system

    NASA Astrophysics Data System (ADS)

    Sung, Po-Chi; Wang, Wei-Chung; Hwang, Chi-Hung; Li, Meng-Hsiu

    2014-12-01

    Thickness uniformity has been a crucial issue for glass plates used in the flat panel display (FPD). However, point-by-point measurement and/or phase-shifting technique must be employed in the current optical interferometric techniques. Therefore, instantaneous full-field thickness measurement cannot be implemented. Besides, the measurement area is limited by the dimensions of optical components employed in the current optical interferometric techniques. In this paper, an optical interferometric system named angular incidence interferometry (AII) was proposed so that large-area full-field thickness measurement can be achieved. By using AII, the full-field continuous phase difference can be determined by using only one interference image. When the thickness at one point of the specimen is known, the full-field thickness distribution can be obtained immediately. Moreover, with the use of only a basic point-expanded laser light and an image acquisition system, no other special optical components are needed in AII. The applicability and feasibility of AII on the measurement of thickness were investigated by a typical commercially available glass plate of 0.7 mm nominal thickness.

  2. Postbuckling response of long thick plates loaded in compression including higher order transverse shearing effects

    NASA Technical Reports Server (NTRS)

    Stein, Manuel; Sydow, Daniel P.; Librescu, Liviu

    1990-01-01

    This paper presents buckling and postbuckling results for compression-loaded simply-supported aluminum plates and composite plates with a symmetric lay-up of thin +/-45-deg plies composed of many layers. Buckling results for aluminum plates of finite length are given for various length-to-width ratios. Asymptotes to the curves based on the buckling results give N(XCr) for plates of infinite length. Postbuckling results for plates with transverse shearing flexibility are compared to results from classical theory for various width-to-thickness ratios. Characteristic curves indicating the average longitudinal direct stress resultant as a function of the applied displacements are calculated based on four different theories: classical von Karman theory using the Kirchhoff assumptions, first-order shear deformation theory, higher-order shear deformation theory, and three-dimensional flexibility theory. Present results indicate that the three-dimensional flexibility theory gives the lowest buckling loads. The higher-order shear deformation theory has fewer unknowns than the three-dimensional flexibility theory but does not take into account through-the-thickness effects. The figures presented show that small differences occur in the average longitudinal direct stress resultants from the four theories that are functions of applied end-shortening displacement.

  3. Postbuckling response of long thick plates loaded in compression including higher order transverse shearing effects

    NASA Technical Reports Server (NTRS)

    Stein, Manuel; Sydow, P. Daniel; Librescu, Liviu

    1990-01-01

    Buckling and postbuckling results are presented for compression-loaded simply-supported aluminum plates and composite plates with a symmetric lay-up of thin + or - 45 deg plies composed of many layers. Buckling results for aluminum plates of finite length are given for various length-to-width ratios. Asymptotes to the curves based on buckling results give N(sub xcr) for plates of infinite length. Postbuckling results for plates with transverse shearing flexibility are compared to results from classical theory for various width-to-thickness ratios. Characteristic curves indicating the average longitudinal direct stress resultant as a function of the applied displacements are calculated based on four different theories: Classical von Karman theory using the Kirchoff assumptions, first-order shear deformation theory, higher-order shear deformation theory, and 3-D flexibility theory. Present results indicate that the 3-D flexibility theory gives the lowest buckling loads. The higher-order shear deformation theory has fewer unknowns than the 3-D flexibility theory but does not take into account through-the-thickness effects. The figures presented show that small differences occur in the average longitudinal direct stress resultants from the four theories that are functions of applied end-shortening displacement.

  4. Orbiter Cold Plate Intergranular Corrosion: Development of NDE Standards and Assessment of NDE Methods

    NASA Technical Reports Server (NTRS)

    Smith, Stephen W.; Winfree, William P.; Piascik, Robert S.

    2002-01-01

    During pre-servicing of a space shuttle (orbiter vehicle, OV-102), helium leak detection of an avionics cold plate identified a leak located in the face sheet oriented towards the support shelf. Subsequent destructive examination of the leaking cold plate revealed that intergranular corrosion had penetrated the 0.017-inch thick aluminum (AA6061) face sheet. The intergranular attack (IGA) was likely caused by an aggressive crevice environment created by condensation of water vapor between the cold plate and support shelf. Face sheet susceptibility to IGA is a result of the brazing process used in the fabrication of the cold plates. Cold plate components were brazed at 1000 F followed by a slow cooling process to avoid distortion of the bonded cold plate. The slow cool process caused excessive grain boundary precipitation resulting in a material that is susceptible to IGA. The objectives of this work are as follows: (1) Develop first-of-a-kind nondestructive evaluation (NDE) standards that contain IGA identical to that found in the orbiter cold plates; and (2) Assess advanced NDE techniques for corrosion detection and recommend methods for cold plate examination. This report documents the results of work performed at Langley Research Center to fulfill these objectives.

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

    NASA Astrophysics Data System (ADS)

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

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

  6. 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.

  7. Postbuckling response of long thick isotropic plates loaded in compression including higher order transverse shearing effects

    NASA Technical Reports Server (NTRS)

    Stein, Manuel; Sydow, P. Daniel; Librescu, Liviu

    1990-01-01

    Buckling and postbuckling results for aluminum plates loaded in compression are presented. The buckling results were plotted to show the effects of thickness on the stress coefficient. Buckling results are given for various length-to-width ratios. Postbuckling results for plates with transverse shearing flexibility are compared to results from classical theory for various width-to-thickness ratios. The plates are considered to be long with side edges simply supported, with edges free of stress and the plates are subjected to longitudinal compressive displacement. Characteristic curves indicating the average longitudinal direct stress resultant as a function of the applied displacements are calculated based on four different theories: Classical von Karman, first-order shear deformation, higher-order shear deformation, and three-dimensional flexibility. Present results indicate that the three-dimensional flexibility theory gives the lowest and therefore, most accurate results. The higher-order shear deformation theory has fewer unknowns than the three-dimensional flexibility but is not as accurate. The figures presented show that small differences occur in the maximum stress resultants and the transverse displacements calculated when the effects of transverse shear are included.

  8. 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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    A detailed quantitative analysis of the microstructure has been performed in three orthogonal planes of 15-mm-thick aluminum plates heavily deformed via two equal channel angular extrusion (ECAE) routes. One route was a conventional route A with no rotation between passes. Another route involved sequential 90 deg rotations about the normal direction (ND) between passes. The microstructure in the center of these plates, and especially the extent of microstructural heterogeneity, has been characterized quantitatively and compared with that in bar samples extruded via either route A or route Bc with 90 deg rotations about the longitudinal axis. Statistically robust data were obtained in this work using gallium enhanced microscopy and EBSD mapping of large sample areas. For the plate processed using route A, the fraction of high-angle boundaries was found to strongly depend on the inspection plane, being smallest in the plane perpendicular to the ND (plane Z), where the largest subgrain size and most profound microstructural heterogeneities were also revealed. In comparison, the plate extruded with 90 deg rotations about the ND was less heterogeneous and contained smaller subgrains in plane Z. Comparing the plate and bar samples, the most refined and least heterogeneous microstructure was observed in the route Bc bar sample. The differences in the microstructure are reflected in the hardness data; the hardness is lowest after ECAE via route A and greatest in the bar sample processed using route Bc.

  10. 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.

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

    SciTech Connect

    Kamas, Tuncay E-mail: victorg@sc.edu Giurgiutiu, Victor E-mail: victorg@sc.edu Lin, Bin E-mail: victorg@sc.edu

    2015-03-31

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

  12. 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.

  13. Feasibility study on welding and cutting methods for thick plate in fusion reactor

    SciTech Connect

    Osaki, T.; Nakayama, Y.; Kobayashi, T.

    1995-12-31

    Application of tungsten-arc inert-gas (TIG) welding with narrow gap has been considered as a hopeful joint method to suppress post welding deformation for thick plates. The authors studied some parameters to predict the post-welding deformation for the narrow gap shape of TIG welding. As for cutting methods, the water jet method was applied for weld joints in this study. Reweld tests by using the TIG welding method were successfully performed under the condition of cutting surface as it was. Results of tensile tests for reweld joints showed no reduction in strength. This reveals a good prospect of providing reweld groove surface without any machining on site.

  14. Three-dimensional free vibration of thick functionally graded annular plates in thermal environment

    NASA Astrophysics Data System (ADS)

    Malekzadeh, P.; Shahpari, S. A.; Ziaee, H. R.

    2010-02-01

    The free vibration analysis of functionally graded (FG) thick annular plates subjected to thermal environment is studied based on the 3D elasticity theory. The material properties are assumed to be temperature dependent and graded in the thickness direction. Considering the thermal environment effects and using Hamilton's principle, the equations of motion are derived. The effects of the initial thermal stresses are considered accurately by obtaining them from the 3D thermoelastic equilibrium equations. The differential quadrature method (DQM) as an efficient and accurate numerical tool is used to solve both the thermoelastic equilibrium and free vibration equations. Very fast rate of convergence of the method is demonstrated. Also, the formulation is validated by comparing the results with those obtained based on the first-order shear deformation theory and also with those available in the literature for the limit cases, i.e. annular plates without thermal effects. The effects of temperature rise, material and geometrical parameters on the natural frequencies are investigated. The new results can be used as benchmark solutions for future researches.

  15. 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.

  16. Mixed finite-difference scheme for analysis of simply supported thick plates.

    NASA Technical Reports Server (NTRS)

    Noor, A. K.

    1973-01-01

    A mixed finite-difference scheme is presented for the stress and free vibration analysis of simply supported nonhomogeneous and layered orthotropic thick plates. The analytical formulation is based on the linear, three-dimensional theory of orthotropic elasticity and a Fourier approach is used to reduce the governing equations to six first-order ordinary differential equations in the thickness coordinate. The governing equations possess a symmetric coefficient matrix and are free of derivatives of the elastic characteristics of the plate. In the finite difference discretization two interlacing grids are used for the different fundamental unknowns in such a way as to reduce both the local discretization error and the bandwidth of the resulting finite-difference field equations. Numerical studies are presented for the effects of reducing the interior and boundary discretization errors and of mesh refinement on the accuracy and convergence of solutions. It is shown that the proposed scheme, in addition to a number of other advantages, leads to highly accurate results, even when a small number of finite difference intervals is used.

  17. Vibration of elastically restrained cross-ply laminated plates with variable thickness

    NASA Astrophysics Data System (ADS)

    Ashour, Ahmed S.

    2005-11-01

    The natural frequencies of symmetrically laminated plates of variable thickness are analyzed using the finite strip transition matrix technique. In this paper, the natural frequencies of such plates are determined for edges with being elastically restrained against both rotation and transition or both. A successive conjunction of the classical finite strip method and the transition matrix method is applied to develop a new modification of the finite strip method to reduce the complexity of the problem. The displacement function is expressed as the product of a basic trigonometric series function in the longitudinal direction and an unknown function that has to be determined in the other direction. Using the new transition matrix, after necessary simplification and the satisfaction of the boundary conditions, yields a set of simultaneous equations that leads to the characteristic matrix of vibration. The mode shapes and the frequency parameters for different combinations of elastic or translational restraint coefficients have been presented and compared with those available from other methods in the literature. Also, the effect of the tapered ratio and the aspect ratio on the natural frequencies and the mode shapes of the plates are presented. The good agreement with other methods demonstrates the validity and the reliability of the proposed method.

  18. 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.

  19. 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.

  20. Influence of a welding sequence on the welding residual stress of a thick plate

    NASA Astrophysics Data System (ADS)

    Ji, S. D.; Fang, H. Y.; Liu, X. S.; Meng, Q. G.

    2005-06-01

    The residual stress in one-groove welding using an ellipsoidal heat source is analysed. The results show that it can ameliorate the residual stress distribution and greatly decrease the peak value of residual stress after welding if the converse welding method is adopted between adjacent layers in a multi-layer weld, or between adjacent beads in every layer. Moreover, the numerical simulation results of the double V-groove thick plate welding model show that the residual tensile stress appears on the weld and nearby, the residual compressive stress appears on the area far away from the weld and the peak value of tensile stress appears on the surface of the weld. Differences in the welding sequence influence the value and the distribution of the welding residual stress greatly, and a more suitable welding sequence can be deduced. The reliability of the numerical simulation results is proved by the experimental results.

  1. Observations related to plate tectonics " Ocean and continent topography, hypsometry, and crustal thickness.

    E-print Network

    Sandwell, David T.

    · Observations related to plate tectonics " Ocean and continent topography, hypsometry, and crustal and gravity anomaly Marine magnetic anomalies " · Plate tectonic theory ­ types of plate boundaries! · Plate of plate tectonics states that the lithosphere (strong layer) is divided into a small number of nearly

  2. Effect of pervaporation plate thickness on the rate of methanol evaporation in a passive vapor-feed direct methanol fuel cell

    NASA Astrophysics Data System (ADS)

    Fauzi, N. F. I.; Hasran, U. A.; Kamarudin, S. K.

    2015-09-01

    In a passive vapor-feed direct methanol fuel cell (DMFC), methanol vapor is typically obtained using a pervaporation plate in a process by which liquid methanol contained in the fuel reservoir undergoes a phase change to vapor in the anodic vapor chamber. This work investigates the effect of pervaporation plate thickness on the rate of methanol evaporation using a three-dimensional simulation model developed by varying the plate thickness. A. The rate of methanol evaporation was measured using Darcy's law. The rate of methanol evaporation was found to be inversely proportional to the plate thickness, where the decrease in thickness inevitably lowers the resistance along the plate and consequently increases the methanol transport through the plate. This shows that the plate thickness has a significant influence on the rate of methanol evaporation and thereby plays an important role in improving the performance of the passive vapor-feed direct methanol fuel cell.

  3. 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

  4. 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.

  5. Analysis of thick isotropic and cross-ply laminated plates by radial basis functions and a Unified Formulation

    NASA Astrophysics Data System (ADS)

    Ferreira, A. J. M.; Roque, C. M. C.; Carrera, E.; Cinefra, M.

    2011-02-01

    In this paper, we combine Carrera's Unified Formulation and a radial basis function collocation technique for predicting the static deformations and free vibration behavior of thin and thick isotropic and cross-ply laminated plates. Through numerical experiments, the capability and efficiency of this collocation technique for static and vibration problems are demonstrated, and the numerical accuracy and convergence are thoughtfully examined.

  6. 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.

  7. Investigating Transition Zone Thickness Variation under the Arabian Plate: Evidence Lacking for Deep Mantle Upwellings

    NASA Astrophysics Data System (ADS)

    Juliá, J.; Tang, Z.; Mai, P. M.; Zahran, H.

    2014-12-01

    Cenozoic volcanic outcrops in Arabia - locally known as harrats - span more than 2000 km along the western half of the Arabian plate, from eastern Yemen to southern Syria. The magmatism is bimodal in character, with older volcanics (30 to 20 My) being tholeiitic-to-transitional and paralleling the Red Sea margin, and younger volcanics (12 Ma to Recent) being transitional-to-strongly-alkalic and aligning in a more north-south direction. The bimodal character has been attributed to a two-stage rifting process along the Red Sea, where the old volcanics would have produced from shallow sources related to an initial passive rifting stage, and young volcanics would have originated from one or more deep-seated mantle plumes driving present active rifting. Early models suggested the harrats would have resulted from either lateral flow from the Afar plume in Ethiopia, or more locally from a separate mantle plume directly located under the shield. Most recently, tomographic images of the Arabian mantle have suggested the northern harrats could be resulting from flow originating at a deep plume under Jordan. In this work, we investigate the location of deep mantle plumes under the Arabian plate by mapping transition zone thickness with teleseismic receiver functions. The transition zone is bounded by seismic discontinuities, nominally at 410 and 660 km depth, originating from phase transitions in the olivine-normative component of the mantle. The precise depth of the discontinuities is strongly dependent on temperature and, due to the opposing signs of the corresponding Clapeyron slopes, positive temperature anomalies are expected to result in thinning of the transition zone. Our dataset consists of ~5000 low-frequency (fc < 0.25 Hz) receiver function waveforms obtained at ~110 broadband stations belonging to a number of permanent and temporary seismic networks in the region. The receiver functions were migrated to depth and stacked along a ~2000 km long record section displaying P-to-S conversions at seismic discontinuities under Western Arabia. Our results display a normal to thicker-than-average transition zone under the study area, suggesting thermal perturbations of the transition zone due to deep mantle upwellings under the western shield and/or Jordan are unlikely.

  8. 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.

  9. Enumeration of heterotrophs, fecal coliforms and Escherichia coli in water: comparison of 3M Petrifilm plates with standard plating procedures.

    PubMed

    Schraft, H; Watterworth, L A

    2005-03-01

    A total of 177 naturally contaminated water samples were analyzed by membrane filtration according to the Standard Methods for the Examination of Water and Wastewater published by the American Public Health Association. Filters were incubated in parallel on mHPC-agar and 3M Petrifilm Aerobic Count Plates (Petrifilm AC plates) for heterotrophic counts. Fecal coliforms and Escherichia coli were enumerated on mFC-agar and 3M Petrifilm E. coli/Coliform Count Plates (Petrifilm EC plates). Typical colonies on each media type were confirmed following standard procedures. Heterotrophic counts were between 10(3) and 10(4) CFU/mL and the average log10 counts obtained on Petrifilm AC plates were about two-fold lower than on mHPC-agar. Counts for fecal coliforms and E. coli were between 10(2) and 10(3) CFU/mL. Average log10 counts for confirmed fecal coliforms obtained on Petrifilm EC plates were slightly lower than on mFC agar with a correlation coefficient of 0.949. The average log10 counts for confirmed E. coli on Petrifilm EC plates and on mFC agar were statistically not different (P=0.126) with a correlation coefficient of 0.879. Specificity of Petrifilm EC plates and mFC agar was evaluated by comparing typical colony counts with confirmed counts. On mFC agar, counts for typical colonies were by 2 log10 CFU higher than the actual confirmed counts. In contrast, on Petrifilm EC plates typical colony counts were almost identical to confirmed colony counts for both fecal coliforms and E. coli. This comparison illustrates the high specificity of Petrifilm EC plates for enumeration of both fecal coliforms and E. coli in water. PMID:15649535

  10. 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

    ...Emissions Standards for New Aircraft Gas Turbine Engines and Identification Plate...amending the emission standards for turbine engine powered airplanes to incorporate...EPA also proposed adopting the gas turbine engine test procedures of...

  11. The characterization of Lamb and Rayleigh waves in plates with ramp-like changes in thickness 

    E-print Network

    Uzzell, Christopher Tinsley

    1994-01-01

    and the geometric aspects of the plate. Changes in frequency spectra and phase of the interrogating wave were used to identify parameters essential to the non-destructive evaluation of these specimens....

  12. 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

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

    SciTech Connect

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

    2013-12-16

    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.

  14. Lithospheric 3-D flexure modelling of the oceanic plate seaward of the trench using variable elastic thickness

    NASA Astrophysics Data System (ADS)

    Manríquez, Paula; Contreras-Reyes, Eduardo; Osses, Axel

    2014-02-01

    When describing the mechanical behaviour of the lithosphere modelled as a thin plate, the most important parameter corresponds to its flexural rigidity, which is commonly expressed through the effective elastic thickness, Te. This parameter is a measure of the stiffness of the plate and defines the maximum magnitude and wavelength of those surface loads that can be supported without suffering unelastic deformation. Realistic 3-D models of the flexural response of the lithosphere near the trench are scarce because of the mathematical and computational complexity. We present a method for determining the flexure of the lithosphere caused by the combined effect of 3-D seamount loading and bending of the lithosphere near the trench. Our method consists on solving numerically the flexure equations of the Reissner-Mindlin thin plate theory, including variable thickness, using the finite element method with mesh adaptation. The method was applied to study the flexure of the oceanic Nazca lithosphere beneath the O'Higgins seamount group which lies ˜70 km seaward of the Chile trench. The results show that an elastic thickness Te of ˜5 km under the seamounts, a Te of ˜15 km far from the trench and a Te of ˜13 km near the trench can explain both, the down deflection of the oceanic Moho and bending of the oceanic lithosphere observed in seismic and gravity profiles. In order to study the impact of high trench curvature on the morphology of the outer rise, we apply the same methodology to study and model the flexure of the lithosphere in the Arica Bend region (14°S-23°S). Results indicate that the Te values are overestimated if the 3-D trench curvature is not included in the modelling.

  15. Vibro-acoustic response of an infinite, rib-stiffened, thick-plate assembly using finite-element analysis.

    PubMed

    Remillieux, Marcel C; Burdisso, Ricardo A

    2012-07-01

    The vibration of and sound radiation from an infinite, fluid-loaded, thick-plate assembly stiffened periodically with ribs are investigated numerically using finite-element analysis. First, numerical simulations are compared to the analytical solutions presented recently for this particular problem [Hull and Welch, J. Sound Vib. 329, 4192-4211 (2010)]. It is shown that the solutions reported in this reference are partially incorrect because the number of modes was not chosen correctly. Subsequently, the numerical model is used to study the effect of repeated and equally spaced void inclusions on the vibro-acoustic response of the system. PMID:22779570

  16. Tectonic plate coupling and elastic thickness derived from the inversion of a steady state viscoelastic model using geodetic data: Application to southern North Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Cohen, Steven C.; Darby, Desmond J.

    2003-03-01

    A steady state viscoelastic model of deformation at an oblique convergence zone is used to analyze crustal velocities deduced from Global Positioning System (GPS) observations in southern North Island, New Zealand. The model is physically more reasonable than elastic dislocation theory because the tectonic plates have finite elastic thicknesses. In an inversion that makes use of Green's functions derived from finite element calculations, we solve for depth-dependent fault backslip rates. The associated chi-squared goodness of fit parameter depends on the values of the elastic thicknesses of the overriding Australian and subducting Pacific Plates. These thicknesses are systematically varied in order to find the chi-squared minimum. We find that: (1) the plates have coupling coefficient between 0.8 and 1.0 to a depth of about 22 km; (2) elastic dislocation theory appears to adequately fit the observations because the effects of viscoelastic flow are small; (3) viscoelastic results depend on the contrast between the elastic moduli of the plates, (4) the trench normal, rather than the trench parallel component of motion is more diagnostic for choosing between models with different parameters; (5) for the favored model (one with a weak continental crust), the estimated value of the Pacific Plate thickness is 40-60 km. Although the estimates of the plate thickness are not tightly constrained, those deduced from geodetic data tend to be larger than those deduced from geologic data, consistent with the idea that thickness estimates depend on the time scale of the loading process.

  17. Postbuckling of long thick plates in compression including higher order transverse shearing effects

    NASA Technical Reports Server (NTRS)

    Stein, Manuel; Sydow, P. D.; Librescu, Liviu

    1990-01-01

    Aluminum plates of various length/width ratios loaded in compression are examined analytically in terms of buckling and postbuckling for comparison with classical theory. The plates are considered to be subjected to longitudinal compressive displacement with no edge stress and are assumed to be simply supported at the side edges. The average longitudinal direct stresses are computed to plot characteristic curves by means of the following theories: 3D flexibility, higher-order shear deformation, first-order shear deformation, and classical von Karman. The 3D flexibility approach yields the lowest results with more unknowns than the higher-order shear-deformation method. The 3D flexibility approach is considered to be the most accurate, and it is shown that the calculated resultants and displacements tend to vary when consideration is given to the effects of transverse shear.

  18. Biomechanical Evaluation of a Mandibular Spanning Plate Technique Compared to Standard Plating Techniques to Treat Mandibular Symphyseal Fractures

    PubMed Central

    Richardson, Matthew; Hayes, Jonathan; Jordan, J. Randall; Puckett, Aaron; Fort, Matthew

    2015-01-01

    Purpose. The purpose of this study is to compare the biomechanical behavior of the spanning reconstruction plate compared to standard plating techniques for mandibular symphyseal fractures. Materials and Methods. Twenty-five human mandible replicas were used. Five unaltered synthetic mandibles were used as controls. Four experimental groups of different reconstruction techniques with five in each group were tested. Each synthetic mandible was subjected to a splaying force applied to the mandibular angle by a mechanical testing unit until the construct failed. Peak load and stiffness were recorded. The peak load and stiffness were analyzed using ANOVA and the Tukey test at a confidence level of 95% (P < 0.05). Results. The two parallel plates' group showed statistically significant lower values for peak load and stiffness compared to all other groups. No statistically significant difference was found for peak load and stiffness between the control (C) group, lag screw (LS) group, and the spanning plate (SP1) group. Conclusions. The spanning reconstruction plate technique for fixation of mandibular symphyseal fractures showed similar mechanical behavior to the lag screw technique when subjected to splaying forces between the mandibular gonial angles and may be considered as an alternative technique when increased reconstructive strength is needed. PMID:26649332

  19. 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

    ...Emissions Standards for New Aircraft Gas Turbine Engines and Identification Plate...EPA also proposed adopting the gas turbine engine test procedures of the...Exhaust Emissions (New Aircraft Gas Turbine Engines) 0 3. Amend Sec....

  20. 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

    ...Emissions Standards for New Aircraft Gas Turbine Engines and Identification Plate...EPA also proposed adopting the gas turbine engine test procedures of ICAO...airplanes that are powered by aircraft gas turbine engines of the classes...

  1. 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.

  2. 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.

  3. Thick Plate Rolling—a Numerical Approach in Comparison with Analytics and Experimental Data

    NASA Astrophysics Data System (ADS)

    Prommer, Hannes; Bojahr, Manuel; Tschullik, Ralf; Kaeding, Patrick

    2011-05-01

    Today, wind turbines are mostly made of glass or carbon fibre. The manufacturing process leads to high precision and quality of the final product. Nevertheless, this fabrication method of rotor blades is very cost intensive and its production technology is not the best in terms of recyclability. In addition to its good recyclability, the handling of steel is well known and its fabrication is inexpensive. Due to these facts an idea of foils to be produced from steel arose. In cooperation with a metal forming company the 3-Dimensional rolling concept came up. Initially, rolling experiments with cold lead plates in a scale of 1:4 are made to simulate the later on used hot steel plates. Such an approach has to be accompanied by fundamental research. This paper sketches the lead rolling experiment and gives an assessment if it is applicable for a hot rolling process with steel. For this purpose, the lead test data are interpreted, the numerical model is explained and results are presented. Furthermore, an analytical flat rolling approach is used to calculate process parameters like stamping force of the upper roll and necessary friction. The applicability and precision of the analytical results are discussed in comparison with the results of the FEM model and the experimental data. Concluding the paper, validity and pitfalls of this concept are outlined and a short outlook for further research is given. The purpose of these considerations is to get closer to process parameters for an experiment in full scale for hot rolling of a rotor blade.

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

    NASA Astrophysics Data System (ADS)

    Suzuki, Hiroshi; Katsuyama, Jinya; Morii, Yukio

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

  5. Mo layer thickness requirement on the ion source back plate for the HNB and DNB ion sources in ITER

    NASA Astrophysics Data System (ADS)

    Singh, M. J.; De Esch, H. P. L.; Hemsworth, R.; Boilson, D.

    2015-04-01

    All the inner surfaces of the ion sources and the upstream surface of the plasma grid of the ITER neutral beam ion sources are proposed to be coated with molybdenum. This is done to avoid sputtering of the base material (Cu or CuCrZr) by the ions in the source plasma (D+, D2+, D3+ or H+, H2+, H3+). The sputtering of Mo by the ions in the source plasma is low compared to that from Cu, and the threshold energy for sputtering ˜80 eV) is high compared to the energy of the ions in the source. However the D2+, H2+ and D+, H+ ions backstreaming from the accelerators will have energies that substantially exceed that threshold and it is important that the Mo layer is not eroded such that the base material is exposed to the source plasma. In the case of the HNB, the backstreaming ion power is calculated to be in the order of ˜1 MW, and the average energy of the backstreaming ions is calculated to be ˜300 keV. The ion sources in the HNB beam lines, 40 A 1 MeV D and 46 A 870 keV H beams, are supposed to operate for a period of 2 x 107 s. For the DNB, 60 A 100 keV H beams, the corresponding number is 1.4 × 106 s considering a beam duty cycle of 3s ON/20s OFF with 5 Hz modulation. The Mo layer on the ion source back plate should be thick enough to survive this operational time. Thickness estimation has been carried out taking into account the sputtering yields (atoms/ion), the energy spectrum of the backstreaming ions and the estimated profiles on the ion source back plate.

  6. Mo layer thickness requirement on the ion source back plate for the HNB and DNB ion sources in ITER

    SciTech Connect

    Singh, M. J.; Hemsworth, R.; Boilson, D.; De Esch, H. P. L.

    2015-04-08

    All the inner surfaces of the ion sources and the upstream surface of the plasma grid of the ITER neutral beam ion sources are proposed to be coated with molybdenum. This is done to avoid sputtering of the base material (Cu or CuCrZr) by the ions in the source plasma (D{sup +}, D{sub 2}{sup +}, D{sub 3}{sup +} or H{sup +}, H{sub 2}{sup +}, H{sub 3}{sup +}). The sputtering of Mo by the ions in the source plasma is low compared to that from Cu, and the threshold energy for sputtering ?80 eV) is high compared to the energy of the ions in the source. However the D{sub 2}{sup +}, H{sub 2}{sup +} and D{sup +}, H{sup +} ions backstreaming from the accelerators will have energies that substantially exceed that threshold and it is important that the Mo layer is not eroded such that the base material is exposed to the source plasma. In the case of the HNB, the backstreaming ion power is calculated to be in the order of ?1 MW, and the average energy of the backstreaming ions is calculated to be ?300 keV. The ion sources in the HNB beam lines, 40 A 1?MeV D and 46 A 870 keV H beams, are supposed to operate for a period of 2 x 10{sup 7} s. For the DNB, 60 A 100 keV H beams, the corresponding number is 1.4 × 10{sup 6} s considering a beam duty cycle of 3s ON/20s OFF with 5?Hz modulation. The Mo layer on the ion source back plate should be thick enough to survive this operational time. Thickness estimation has been carried out taking into account the sputtering yields (atoms/ion), the energy spectrum of the backstreaming ions and the estimated profiles on the ion source back plate.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  8. 78 FR 59065 - Interview Room Recording System Standard and License Plate Reader Standard Workshops

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ...Institute of Justice, Department of Justice. ACTION: Notice of the Interview...SUMMARY: The National Institute of Justice (NIJ) and the International Association...and License Plate Readers used by criminal justice agencies. Sessions are...

  9. 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

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Parts 34 and 45 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 63015-63017...

  10. 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...

  11. Biomechanical analysis of a new carbon fiber/flax/epoxy bone fracture plate shows less stress shielding compared to a standard clinical metal plate.

    PubMed

    Bagheri, Zahra S; Tavakkoli Avval, Pouria; Bougherara, Habiba; Aziz, Mina S R; Schemitsch, Emil H; Zdero, Radovan

    2014-09-01

    Femur fracture at the tip of a total hip replacement (THR), commonly known as Vancouver B1 fracture, is mainly treated using rigid metallic bone plates which may result in "stress shielding" leading to bone resorption and implant loosening. To minimize stress shielding, a new carbon fiber (CF)/Flax/Epoxy composite plate has been developed and biomechanically compared to a standard clinical metal plate. For fatigue tests, experiments were done using six artificial femurs cyclically loaded through the femoral head in axial compression for four stages: Stage 1 (intact), stage 2 (after THR insertion), stage 3 (after plate fixation of a simulated Vancouver B1 femoral midshaft fracture gap), and stage 4 (after fracture gap healing). For fracture fixation, one group was fitted with the new CF/Flax/Epoxy plate (n?=?3), whereas another group was repaired with a standard clinical metal plate (Zimmer, Warsaw, IN) (n?=?3). In addition to axial stiffness measurements, infrared thermography technique was used to capture the femur and plate surface stresses during the testing. Moreover, finite element analysis (FEA) was performed to evaluate the composite plate's axial stiffness and surface stress field. Experimental results showed that the CF/Flax/Epoxy plated femur had comparable axial stiffness (fractured?=?645?±?67?N/mm; healed?=?1731?±?109?N/mm) to the metal-plated femur (fractured?=?658?±?69?N/mm; healed?=?1751?±?39?N/mm) (p?=?1.00). However, the bone beneath the CF/Flax/Epoxy plate was the only area that had a significantly higher average surface stress (fractured?=?2.10?±?0.66?MPa; healed?=?1.89?±?0.39?MPa) compared to bone beneath the metal plate (fractured?=?1.18?±?0.93?MPa; healed?=?0.71?±?0.24?MPa) (p?plated femurs at the vicinity of nearest screw just proximal to fracture (stage 3), 21?MPa for composite and 24?MPa for metal-plated femurs at the vicinity of screw farthest away distally from fracture (stage 4). These results confirm that the new CF/Flax/Epoxy material could be a potential candidate for bone fracture plate applications as it can simultaneously provide similar mechanical stiffness and lower stress shielding (i.e., higher bone stress) compared to a standard clinical metal bone plate. PMID:24828985

  12. 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.

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

    PubMed

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

    2016-01-01

    We propose the use of thickness-twist (TT) wave modes of an AT-cut quartz crystal plate resonator for measurement of material parameters, such as stiffness, density and material gradient, of a functionally graded material (FGM) layer on its surface, whose material property varies exponentially in thickness direction. A theoretical analysis of dispersion relations for TT waves is presented using Mindlin's plate theory, with displacement mode shapes plotted, and the existence of face-shear (FS) wave modes discussed. Through numerical examples, the effects of material parameters (stiffness, density and material gradient) on dispersion curves, cutoff frequencies and mode shapes are thoroughly examined, which can act as a theoretical reference for measurements of unknown properties of FGM layer. PMID:26254981

  14. 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

    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.

  15. Standardization of proton-induced x-ray emission technique for analysis of thick samples

    NASA Astrophysics Data System (ADS)

    Ali, Shad; Zeb, Johar; Ahad, Abdul; Ahmad, Ishfaq; Haneef, M.; Akbar, Jehan

    2015-09-01

    This paper describes the standardization of the proton-induced x-ray emission (PIXE) technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials (SRMs) were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 MeV obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.

  16. Investigation of the properties of superconducting plates with a thickness of the order of the coherence length ? in the framework of the Ginzburg-Landau theory

    NASA Astrophysics Data System (ADS)

    Bezotosnyi, P. I.; Gavrilkin, S. Yu.; Lykov, A. N.; Tsvetkov, A. Yu.

    2015-07-01

    The properties of superconducting plates with a thickness of the order of the coherence length ? have been investigated by numerically solving the system of one-dimensional Ginzburg-Landau equations. The equations have been solved using boundary conditions of the general form for the order parameter, which makes it possible to take into account the influence of the boundaries of the plate on its superconducting properties. The behavior of the critical current and critical magnetic field as a function of external parameters has been analyzed. It has been shown that the inclusion of the influence of the boundary in the calculations leads to results that are in better agreement with the experimental data.

  17. 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.

  18. Thick Films of Viscous Fluid Coating a Plate Withdrawn from a Liquid Reservoir J. H. Snoeijer,1

    E-print Network

    June 2008) We consider the deposition of a film of viscous liquid on a flat plate being withdrawn from is measured by the capillary number Ca U= , where is the viscosity and the surface tension. At the foot but exhibit a bump at the foot of the film [cf. Fig. 1(c)]. As we will explain in more detail below

  19. Parallel-plate capacitor measurements of the superfluid wall-film thickness in a 3He/4He mixture of 3He mole fraction x = 0.75

    NASA Astrophysics Data System (ADS)

    Deng, Weimin; Zimmermann, W., Jr.

    2009-02-01

    A thin 4He-rich superfluid film coats solid surfaces in contact with bulk normal liquid 3He/4He mixtures in a narrow region of the mixture phase diagram at saturated vapor pressure that adjoins the lambda line, the tricritical point, and the 3He-rich branch of the phase-separation curve. Recent arguments suggest that near the tricritical point, the thickness of the film is governed not only by van der Waals forces and gravity but also by Casimir and Helfrich forces that limit the thickness as the phase-separation curve is approached. Experimental evidence has been presented both showing and failing to show this phenomenon. In the present work, parallel-plate capacitor measurements of a mixture having a 3He mole fraction x = 0.75 show a film thickness of from ~ 14 to ~ 22 nm as the phase-separation curve is first reached from higher temperature, depending on choice of background subtraction, whereas van der Waals forces limited only by gravity would be expected in our cell to yield a thickness of ~ 31 nm, rising in the first few mK below the phase-separation temperature to ~ 43 nm. Despite various uncertainties and anomalies, the results suggest that additional forces may be at work.

  20. Validity Study of a Jump Mat Compared to the Reference Standard Force Plate

    PubMed Central

    Rogan, Slavko; Radlinger, Lorenz; Imhasly, Caroline; Kneubuehler, Andrea; Hilfiker, Roger

    2015-01-01

    Background: In the field of vertical jump diagnostics, force plates (FP) are the reference standard. Recently, despite a lack of evidence, jump mats have been used increasingly. Important factors in favor of jumping mats are their low cost and portability. Objectives: This validity study compared the Haynl-Elektronik jump mat (HE jump mat) with the reference standard force plate. Materials and Methods: Ten healthy volunteers participated and each participant completed three series of five drop jumps (DJ). The parameters ground contact time (GCT) and vertical jump height (VJH) from the HE jump mat and the FP were used to evaluate the concurrent validity. The following statistical calculations were performed: Pearson's correlation (r), Bland-Altman plots (standard and for adjusted trend), and regression equations. Results: The Bland-Altman plots suggest that the HE jump mat measures shorter contact times and higher jump heights than the FP. The trend-adjusted Bland-Altman plot shows higher mean differences and wider wing-spreads of confidence limits during longer GCT. During the VJH the mean differences and the wing-spreads of the confidence limits throughout the range present as relatively constant. The following regression equations were created, as close as possible to the true value: GCT = 5.920385 + 1.072293 × [value HE jump mat] and VJH = -1.73777 + 1.011156 × [value HE jump mat]. Conclusions: The HE jump mat can be recommended in relation to the validity of constraints. In this study, only a part of the quality criteria were examined. For the final recommendation it is advised to examine the HE jump mat on the other quality criteria (test-retest reliability, sensitivity change). PMID:26715970

  1. Influence of Laser Wavelength on Melt Bath Dynamics and Resulting Seam Quality at Welding of Thick Plates

    NASA Astrophysics Data System (ADS)

    Haug, P.; Rominger, V.; Speker, N.; Weber, R.; Graf, T.; Weigl, M.; Schmidt, M.

    CO2- and solid-state lasers are the most widely used beam sources. Owing to their different physical beam characteristics, these two types of laser differ fundamentally not only in how the beam is guided but also in their process behavior during deep penetration welding. Almost all industrial applications in thick material > 8 mm have to be full penetration welds to increase fatigue strength, for example in ship building, pipeline construction, train and rail construction or power-train, Holzer et al., 2011. Therefore process behavior and limits at full penetration will be analyzed in detail for both beam sources.

  2. "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.

  3. 76 FR 57913 - Amendments to National Emission Standards for Hazardous Air Pollutants for Area Sources: Plating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-19

    ...electroforming; electroless plating, including thermal metal spraying, chromate conversion coating...electroforming; electroless plating, including thermal metal spraying, chromate conversion coating...practices for new and existing tanks, thermal spraying equipment, and dry...

  4. 76 FR 35744 - Amendments to National Emission Standards for Hazardous Air Pollutants for Area Sources: Plating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ...telephone number for the Air and Radiation Docket is (202) 566-1742...electroless plating, including thermal metal spraying, chromate conversion...electroless plating, including thermal metal spraying, chromate...for new and existing tanks, thermal spraying equipment, and...

  5. Plate-Tectonic Analysis of Shallow Seismicity: Apparent Boundary Width, beta-Value, Corner Magnitude, Coupled Lithosphere Thickness, and Coupling in 7 Tectonic Settings

    NASA Astrophysics Data System (ADS)

    Bird, P.; Kagan, Y. Y.

    2003-12-01

    A new plate model [Bird, 2003, G3, 10.1029/2001GC000252] is used to analyze the mean seismicities of 7 types of plate boundary (CRB continental rift boundary, CTF continental transform fault, CCB continental convergent boundary, OSR oceanic spreading ridge, OTF oceanic transform fault, OCB oceanic convergent boundary, SUB subduction zone). We compare the plate-like (non-orogen) regions of model PB2002 with the CMT catalog to select apparent boundary half-widths, and then assign 95% of shallow earthquakes to one of these settings. A tapered Gutenberg-Richter model of the frequency/moment relation is fit to the subcatalog for each setting by maximum-likelihood. Best-fitting ? values range from 0.53 to 0.92, but all 95%-confidence ranges are consistent with a common value of 0.61-0.66. To better determine some corner magnitudes we expand the subcatalogs by: (1) inclusion of orogens; and (2) inclusion of years 1900-1975 from the catalog of Pacheco and Sykes [1992]. Combining both earthquake statistics and the plate-tectonic constraint on moment rate, corner magnitudes include: CRB 7.64-.26+.76, CTF 8.01-.21+.45, CCB 8.46-.39+.21, OCB 8.04-.22+.52, and SUB 9.58-.46+.48. Coupled lithosphere thicknesses are found to be: CRB 3.0-1.4+7.0 km; CTF 8.6-4.1+11 km; CCB 18-11+? km; OSR 0.13-0.09+.13 km for normal-faulting and 0.40-.21+? km for strike-slip; OTF 12-7.1+?, 1.6-0.5+1.4, and 1.5-0.6+1.2 km at low, medium, and high velocities; OCB 3.8-2.3+13.7 km, and SUB 18.0-10.8+? km. Generally high coupling of subduction and continental plate boundaries suggests that here all seismic gaps are dangerous unless proven to be creeping. Generally low coupling within oceanic lithosphere suggests a different model of isolated seismic asperities surrounded by large seismic gaps which may be permanent.

  6. 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. )

    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.

  7. High-temperature crack-arrest tests using 152-mm-thick SEN wide plates of low-upper-shelf base material: Tests WP-2. 2 and WP-2. 6

    SciTech Connect

    Naus, D.J.; Keeney-Walker, J.; Bass, B.R.; Iskander, S.K. ); Fields, R.J.; deWit, R.; Low, S.R. III )

    1990-02-01

    Two 152-mm-thick wide-plate crack-arrest tests (WP-2 series) are discussed in this report. Each test used a 1 {times} 1 {times} 0.15 m thick single-edge-notch specimen (a/w = 0.2), fabricated from a low-upper-shelf base material, that was subjected to a linear thermal gradient along the plane of crack propagation. The tests were conducted at the National Institute of Standards and Technology and were designed to provide fracture-toughness measurements at temperatures approaching or above the onset of the Charpy upper-shelf regime in a rising toughness region and with an increasing driving force. Results obtained from these tests have produced crack-arrest toughness values well above the limit recognized by the current ASME guidelines (220 MPa {center dot} {radical}m) with arrests occurring at 44 to 102{degrees}C above the material DW{sub NDT} (60{degrees}C). The fracture data support (1) the use of fracture mechanics concepts to analyze cleavage run-arrest events, (2) the treatment of cleavage run-arrest and ductile fracture modes as separate events, and (3) the fact that cleavage arrest occurs above the ASME limit. 124 refs., 83 figs., 18 tabs.

  8. The thickness of the lithospheric plate and the parameters of the asthenosphere beneath the Scandinavian Shield according to the BEAR experiment

    NASA Astrophysics Data System (ADS)

    Kovtun, A. A.; Vardanyants, I. L.

    2015-07-01

    The article summarizes the works on studying the upper mantle structure beneath the Scandinavian Shield from the magnetotelluric (MT) data of the BEAR experiment combined with the global magnetovariational (MV) data. During the past few years, we improved the technique of joint interpretation of MT and global MV data, which enabled us to draw more reliable conclusions concerning the structure of the upper mantle and outline the ways of further increasing the efficiency of the MT method in determining the thickness of the lithospheric plate and geoelectrical parameters of the asthenosphere. Our study of the upper mantle structure from the BEAR data suggests the presence of the asthenosphere at a depth of 200 to 300 km with the electric resistivity of 20-40 ? m, which corresponds to a 1-2% melt of the mantle material. For obtaining more exact estimates, the BEAR data should be interpreted together with the MV data from the observatories located in the Scandinavian Shield. In the future, this approach will probably enable a more reliable zoning of the Scandinavian shield according to the thickness and depth of the asthenosphere.

  9. 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.

  10. 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.

  11. Standard guide for mutual inductance bridge applications for wall thickness determinations in boiler tubing

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This guide describes a procedure for obtaining relative wall thickness indications in ferromagnetic and non-ferromagnetic steels using the mutual inductance bridge method. The procedure is intended for use with instruments capable of inducing two substantially identical magnetic fields and noting the change in inductance resulting from differing amounts of steel. It is used to distinguish acceptable wall thickness conditions from those which could place tubular vessels or piping at risk of bursting under high temperature and pressure conditions. 1.2 This guide is intended to satisfy two general needs for users of industrial Mutual Inductance Bridge (MIB) equipment: (1) the need for a tutorial guide addressing the general principles of Mutual Inductance Bridges as they apply to industrial piping; and (2) the need for a consistent set of MIB performance parameter definitions, including how these performance parameters relate to MIB system specifications. Potential users and buyers, as well as experienced M...

  12. 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

  13. 76 FR 35744 - Amendments to National Emission Standards for Hazardous Air Pollutants for Area Sources: Plating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... amending this rule? On July 1, 2008 (73 FR 37741), we issued the NESHAP for Area Sources: Plating and... Executive Order 12866 (58 FR 51735, October 4, 1993) and is therefore not subject to review under the... Order 13175 (65 FR 67249, November 6, 2000). This final rule makes certain technical corrections...

  14. 76 FR 57913 - Amendments to National Emission Standards for Hazardous Air Pollutants for Area Sources: Plating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-19

    ... direct final rule published at 76 FR 35750 on June 20, 2011. ADDRESSES: Docket: All documents in the... Air Pollutants for Area Sources: Plating and Polishing'' which was published on June 20, 2011 (76 FR... (76 FR 35806) published on the same day as a direct final rule, EPA will not institute a...

  15. Bauer Core Standard Protocol Title: Using the Spectramax Gemini XS Fluorescent Plate Reader

    E-print Network

    Needleman, Daniel

    (eg Costar plate sold by VWR cat # 29444-018) 2.2. Fluorescent or Luminescent samples (100ul volume) 3 common assay, 1 scan/well, up to 4 wavelengths. Use autocutoff to ensure excitation wavelength isn't detected. 5.3.1.2. Kinetic: will scan several times over selected run time. Choose run time and interval. 5

  16. Reappraising elastic thickness variation at oceanic trenches

    NASA Astrophysics Data System (ADS)

    Bry, Madeleine; White, Nicky

    2007-08-01

    We reassess the variation of elastic thickness as a function of lithospheric plate age using a global database of bathymetric and free-air gravity profiles which are perpendicular to oceanic trenches. As in many previous studies, our starting point is the well-known floating elastic plate model. In order to remove the influence of short-wavelength features not associated with lithospheric bending, adjacent profiles from 10-Myr bins have been stacked together to construct average profiles with standard deviations. Each average profile was then inverted in a two-stage procedure. First, singular value decomposition was used to determine two unknown flexural parameters, together with a regional slope and offset, for any given elastic thickness. This procedure was repeated for a range of elastic thicknesses. Second, residual misfit was plotted as a function of elastic thickness, and the global minimum was identified. This two-stage procedure makes no prior assumptions about magnitude of the load, size of the bending moment, or whether the elastic plate is broken/continuous. We obtained excellent fits between theory and observation for both bathymetric and gravity profiles from lithosphere with an age range of 0-150 Ma. The shape of the residual misfit function indicates the degree of confidence we have in our elastic thickness estimates. The lower limit of elastic thickness is usually well determined but upper limits are often poorly constrained. Inverse modeling was carried out using a range of profile lengths (250-300, 500, and 700 km). In general, our estimates show no consistent increase of elastic thickness as a function of plate age. This surprising result is consistent with recent reassessments of elastic thickness beneath seamounts and implies either that elastic thickness is independent of plate age or that elastic thickness cannot be measured with sufficient accuracy to reveal such a relationship. Modeling of short free-air gravity profiles (250-300 km) does tentatively suggest that elastic thickness increases linearly from 5 to 10 km between 0 and 20 Ma and from 10 to 15 km between 20 and 150 Ma. This variation roughly matches the depth to the 200°C isotherm which corresponds to an homologous temperature of 0.4 for wet peridotite. Unfortunately, for longer profile lengths, there is no temporal dependence, and elastic thicknesses vary considerably for all plate ages. Bathymetric profile modeling yields similar results although uncertainties are larger.

  17. Correction of Thick Foil Errors in Prompt Neutron (CALIFORNIUM-252 Nu), Fission Cross Section (sigma(f)) and Other Ionization Chamber Fission Data Standards.

    NASA Astrophysics Data System (ADS)

    Cohensedgh, Farhad

    This research resolves two problems that have long been of important concern in experimental fission physics: (1) determination of pulse height distribution response of ionization chambers in fission fragment detection measurements, and (2) correction of "thick-foil effect" systematic errors in standard values of the fundamental parameters of fission physics--the average number of prompt neutrons per fission (=nu), absolute fission activity and true fission rate of samples (TFR), and isotopic fission cross sections (sigma _{f}). Results are obtained by a comprehensive digital simulation of the electrostatics and pulse height distribution response of the parallel-plate, ungridded, electron-pulse ionization fission chamber together with prompt neutron -fragment multiplicity and angular distribution correlations, neutron-fragment coincidence detection and related variations in the 4pi^here around the chamber for a wide range of the relevant factors--foil thickness, alpha particle interference bias level, fission detector configuration characteristics, fissile isotopes (^{252}Cf, ^{235}U, etc.) and other experimental parameters. Isotope-specific double-energy (E_1,E_2) natural variations in fragment spectrum, in fragment-specific range-energy (dE/dx) relations and in prompt neutron-fragment multiplicity (nu) and nuclear temperature dependent angular distribution correlations are simulated in detail. Detailed results are obtained for double-energy, fragment-specific count loss fractions resulting from in -foil fragment absorption and from alpha -interference discrimination as well as for chamber detection efficiency, fragment spectrum distortion and prompt neutron -fragment coincidence detection distribution variations. Decay alpha pulse pileup statistics are discussed, and the behavior of and factors affecting the fragment pulse height distribution tail are analyzed in detail. Fragment pairs and prompt neutrons issued from them are tracked in the 4pi^ace around the chamber. Light-to-heavy fragment detection ratio variations in neutron-gated coincidence measurements are also obtained in 4pi space. Effects of these systematics on absolute, relative and ratio measurements of fundamental fission parameters are discussed. Magnitudes and mechanisms of production of thick-foil errors are identified and analyzed in detail, and methods for correcting these errors and for improving measurement setup design are given.

  18. Comparison of 3M Petrifilm Aerobic Count Plates to standard plating methodology for use with AOAC antimicrobial efficacy methods 955.14, 955.15, 964.02, and 966.04 as an alternative enumeration procedure: collaborative study.

    PubMed

    Nelson, Maria T; LaBudde, Robert A; Tomasino, Stephen F; Pines, Rebecca M

    2013-01-01

    A multilaboratory study was conducted to determine the equivalence of the 3M Petrifilm Aerobic Count Plate and standard plating methodology for measuring viable bacteria and spores recovered from hard-surface carriers (stainless steel and porcelain), also known as "control carrier counts," used in AOAC antimicrobial efficacy test methods. Six laboratories participated in the study in which carriers inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, and spores of Bacillus subtilis were evaluated using 3M Petrifilm Aerobic Count (AC) plates and standard plating side-by-side. The data were analyzed using a matched-pair t-test to determine the between-method effect with confidence intervals. For all test organisms pooled across all laboratories, the mean difference in log10 concentration between the standard plate count method and 3M Petrifilm AC Plates was -0.012, with a 95% confidence interval of (-0.090, +0.066), which was well within the -0.5, +0.5 interval established as the acceptance criterion. The between-carrier SD averaged 0.139; the between-replicate SD was 0.050. The carrier reproducibility, given that a single replicate per carrier is done, was estimated to be 0.148. Although differences were seen in the final concentrations of the test organisms among laboratories, there were no statistical differences between the enumeration methods. Based on the results from this study, 3M Petrifilm AC Plates are equivalent to standard plating methodology and can be used as an alternative procedure for the enumeration of test organisms used in AOAC Methods 955.14, 955.15, 964.02, and 966.04. PMID:24000742

  19. Review of Consensus Standard Spectra for Flat Plate and Concentrating Photovoltaic Performance

    SciTech Connect

    Myers, D.

    2011-09-01

    Consensus standard reference terrestrial solar spectra are used to establish nameplate ratings for photovoltaic device performance at standard reporting conditions. This report describes reference solar spectra developed in the United States and international consensus standards community which are widely accepted as of this writing (June 2011).

  20. 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).

  1. 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

    ... kilonewtons (kN) (76 FR 45012). The EPA also proposed adopting the gas turbine engine test procedures of the... 18, 2012 (77 FR 36342), and was effective July 18, 2012. On December 31, 2012, the FAA published a final rule with a request for comments (77 FR 76842) adopting the EPA's new emissions standards in...

  2. 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

    ... engines with rated thrusts greater than 26.7 kilonewtons (kN) (76 FR 45012). The EPA also proposed...). The final rule adopting these proposals was published on June 18, 2012 (77 FR 36342), and was... (77 FR 76842) adopting the EPA's new emissions standards in part 34. Although the EPA's NPRM...

  3. 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.

  4. 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.

  5. Overriding Plate Controls on Subduction Zone Evolution

    NASA Astrophysics Data System (ADS)

    Sharples, W. K.; Jadamec, M. A.; Moresi, L. N.; Capitanio, F. A.

    2014-12-01

    Seismic data, rock deformation experiments, and geochemical studies indicate variability in the thickness, buoyancy, and strength of the lithosphere at plate boundaries. However, geodynamic models of subduction commonly either omit an overriding plate or do not investigate role of the variation in overriding plate properties on the subduction evolution. We present time-dependent numerical models of subduction that vary the overriding plate thickness, strength, and density and allow for a plate interface that evolves with time via an anisotropic brittle failure rheology. We examine the emergence of (a) asymmetric versus symmetric subduction, (b) trench retreat versus advance, (c) subduction zone geometry, (d) slab stagnation versus penetration into the lower mantle, and (e) flat slab subduction. The majority of the models result in sustained asymmetric subduction. The models demonstrate that trench retreat is correlated with a thin overriding plate, whereas, trench advance is correlated with a thick and/or strong overriding plate. Slab dip, measured at a depth below the plate boundary interface, has a negative correlation with an increase in overriding plate thickness. Overriding plate thickness exerts a first order control over slab penetration into the lower mantle, with penetration most commonly occurring in models with a thick overriding plate. Periods of flat slab subduction occur with thick, strong overriding plates producing strong plate boundary interface coupling. The results provide insight into how the overriding plate plays a role in establishing advancing and retreating subduction, as well as providing an explanation for the variation of slab geometry observed in subduction zones on Earth.

  6. 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.

  7. 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.

  8. Eddy current thickness measurement apparatus

    DOEpatents

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

    2015-06-16

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

  9. Technical note: enumeration of mesophilic aerobes in milk: evaluation of standard official protocols and Petrifilm aerobic count plates.

    PubMed

    Freitas, R; Nero, L A; Carvalho, A F

    2009-07-01

    Enumeration of mesophilic aerobes (MA) is the main quality and hygiene parameter for raw and pasteurized milk. High levels of these microorganisms indicate poor conditions in production, storage, and processing of milk, and also the presence of pathogens. Fifteen raw and 15 pasteurized milk samples were submitted for MA enumeration by a conventional plating method (using plate count agar) and Petrifilm Aerobic Count plates (3M, St. Paul, MN), followed by incubation according to 3 official protocols: IDF/ISO (incubation at 30 degrees C for 72 h), American Public Health Association (32 degrees C for 48 h), and Brazilian Ministry of Agriculture (36 degrees C for 48 h). The results were compared by linear regression and ANOVA. Considering the results from conventional methodology, good correlation indices and absence of significant differences between mean counts were observed, independent of type of milk sample (raw or pasteurized) and incubation conditions (IDF/ISO, American Public Health Association, or Ministry of Agriculture). Considering the results from Petrifilm Aerobic Count plates, good correlation indices and absence of significant differences were only observed for raw milk samples. The microbiota of pasteurized milk interfered negatively with the performance of Petrifilm Aerobic Count plates, probably because of the presence of microorganisms that poorly reduce the dye indicator of this system. PMID:19528584

  10. Thick Toenails

    MedlinePLUS

    The official consumer website of: Visit ACFAS.org | About ACFAS | Información en Español Advanced Search Home » Foot & Ankle Conditions » Thick Toenails Text Size Print Bookmark Thick Toenails Toenails will often become thick as an individual grows older. Thickening may also occur as ...

  11. Natural vibrations of laminated anisotropic plates

    NASA Technical Reports Server (NTRS)

    Reddy, J. N.; Kuppusamy, T.

    1984-01-01

    This paper contains a description of the three-dimensional elasticity equations and the associated finite element model for natural vibrations of laminated rectangular plates. The numerical results for natural frequencies are compared with those obtained by a shear deformable plate theory. A number of cross-ply and angle-ply rectangular plates are analyzed for natural frequencies. For relatively thick plates, the plate element predicts frequencies higher than those predicted by the 3-D element.

  12. Plate motion

    SciTech Connect

    Gordon, R.G. )

    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. Shells with Thickness Distension P. Podio-Guidugli

    E-print Network

    .1 Free Vibrations of Linearly Elastic Plates . . . . . . . . . . . . . . . 25 7.2 Shearing and Thickness oscillations of linearly elastic plates--in particular, thickness-distension waves-- are studied. 1Shells with Thickness Distension A. DiCarlo P. Podio-Guidugli W. O. Williams July 23, 1999

  14. ERROR ESTIMATES FOR LOW-ORDER ISOPARAMETRIC QUADRILATERAL FINITE ELEMENTS FOR PLATES

    E-print Network

    Duran, Ricardo

    of the plate thickness. We also obtain error estimates for the approximation of the plate vibration problem widely used for the anal- ysis of thin or moderately thick elastic plates. It is now very well understood, optimal order error estimates, valid uniformly on the plate thickness, have been obtained for several

  15. 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.

  16. Comparison of Buffered, Acidified Plate Antigen to Standard Serologic Tests for the Detection of Serum Antibodies to Brucella abortus in Elk (Cervus canadensis).

    PubMed

    Clarke, P Ryan; Edwards, William H; Hennager, Steven G; Block, Jean F; Yates, Angela M; Ebel, Eric; Knopp, Douglas J; Fuentes-Sanchez, Antonio; Jennings-Gaines, Jessica; Kientz, Rebecca L; Simunich, Marilyn

    2015-07-01

    Brucellosis (caused by the bacterium Brucella abortus) is a zoonotic disease endemic in wild elk (Cervus canadensis) of the Greater Yellowstone Ecosystem, US. Because livestock and humans working with elk or livestock are at risk, validated tests to detect the B. abortus antibody in elk are needed. Using the ?-statistic, we evaluated the buffered, acidified plate antigen (BAPA) assay for agreement with the results of the four serologic tests (card test [card], complement fixation test [CF], rivanol precipitation plate agglutination test [RIV], standard plate agglutination test [SPT]) that are approved by the US Department of Agriculture for the detection of the B. abortus antibody in elk. From 2006 to 2010, serum samples collected from elk within B. abortus-endemic areas (n = 604) and nonendemic areas (n = 707) and from elk culture-positive for B. abortus (n = 36) were split and blind tested by four elk serum diagnostic laboratories. ?-Values showed a high degree of agreement for the card (0.876), RIV (0.84), and CF (0.774) test pairings and moderate agreement for the SPT (0.578). Sensitivities for the BAPA, card, RIV, CF, and SPT were 0.859, 0.839, 0.899, 1.00, and 0.813, whereas specificities were 0.986, 0.993, 0.986, 0.98, and 0.968, respectively. The positive predictive values and the negative predictive values were calculated for 2.6%, 8.8%, and 16.2% prevalence levels. These findings suggest the BAPA test is a suitable screening test for the B. abortus antibodies in elk. PMID:25984771

  17. Forming Weld Lands On Metal Plates

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1994-01-01

    Forming shoe pounds edge of newly inserted plate workpiece. After many passes of shoe and advances of plate, thick land builds up at edge. Workpiece heated to enable metal to flow without strain hardening. Proposed upset-forming process replaces relatively expensive, time-consuming, and wasteful process in which integral weld lands created by machining metal away from plates everywhere except at lands.

  18. Injection moulded low cost bipolar plates for PEM fuel cells

    NASA Astrophysics Data System (ADS)

    Heinzel, A.; Mahlendorf, F.; Niemzig, O.; Kreuz, C.

    The development of bipolar plates that can be produced by standard mass production techniques is a main issue for the commercialization of PEM fuel cells, as bipolar plates contribute significantly to the cost structure of PEM stacks. In recent years, the University of Duisburg-Essen together with the Zentrum für BrennstoffzellenTechnik GmbH (ZBT) has identified a number of carbon-polymer composites with densities of 1.6 g/cm 3, specific bulk conductivities between 5 and 150 S/cm and material prices between 2 and 10 €/kg. Standard composite mixtures consist of a thermoplast and a carbon compound mixture with additional additives to increase the conductivity of the compound material. The composites generally show high corrosion resistance in the PEM fuel cell environment. Composite material samples proved to be absolutely stable in immersion tests in sulphuric acid and deionized water under pure oxygen atmosphere for several thousand hours. ZBT has successfully demonstrated the production of bipolar plates by injection moulding with cycle times of 30-60 s. With the help of tailored moulds injection moulding of bipolar plates becomes price competitive even for comparatively small series in the range of several thousand plates. PEM stacks with injection moulded bipolar plates of 2.5-4 mm thickness and an electrical power of up to 200 W have been constructed and successfully operated.

  19. 7 CFR 51.2091 - Thickness.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Almonds in the Shell Definitions § 51.2091 Thickness. Thickness means the greatest dimension between the two...

  20. General properties of the acoustic plate modes at different temperatures.

    PubMed

    Anisimkin, V I; Anisimkin, I V; Voronova, N V; Pu?hkov, Yu V

    2015-09-01

    Using acoustic plate modes with SH-polarization and quartz crystal with Euler angles 0°, 132.75°, 90°, as an example, general properties of the acoustic plate modes at different temperatures are studied theoretically and experimentally in the range from -40 to +80°C. It is shown that in addition to well-known parameters responsible for temperature characteristics of acoustic waves the temperature coefficients of the acoustic plate modes depend on the mode order n, plate thickness h/?, and expansion of the plate in direction of its thickness (h - thickness, ? - acoustic wavelength). These properties permit the mode sensitivity to be increased or decreased without replacing plate material and orientation. PMID:26002698

  1. Glued Joint Behavior of Ribs for Wood-Based Composite Plates

    NASA Astrophysics Data System (ADS)

    Frolovs, G.; Rocens, K.; Sliseris, J.

    2015-11-01

    This article presents experimental investigations of composite sandwich plywood plates with cell type core and their connections between skin layers of birch plywood and a core of straight and curved plywood honeycomb-type ribs. This shape of core ribs provides several improvements for these plates in the manufacturing process as well as improves the mechanical properties of plywood plates. This specific form of ribs allows simplifying the manufacturing of these plates although it should be detailed and improved. The most typical cases (series of specimens) were compared to the results obtained from FEM (ANSYS) simulations. All thicknesses of elements are chosen according to plywood supplier assortment. Standard birch plywood (Riga Ply) plates were used - three layer plywood was chosen for skin elements (Surfaces) and three or five layer plywood was chosen for edge elements. Different bond pressures were taken to compare their influence on joint strength and stiffness.

  2. Calculation of the Parameters for a Superconducting Thin Plate within Ginzburg-landau Theory

    NASA Astrophysics Data System (ADS)

    Bezotosnyi, P. I.; Gavrilkin, S. Yu.; Lykov, A. N.; Tsvetkov, A. Yu.

    The behavior of a superconducting plate with transport current in a magnetic field parallel to its surface was studied by using numerical solution of Ginzburg-Landau (GL) equations. Boundary conditions for the order parameter in their general form have been used. The boundary conditions allow to consider the influence of the plate's boundaries on the superconducting state inside it. According to the calculations some features of the dependences of critical current and critical magnetic field in the parallel to the plate's surface direction as a function of the plate thickness have been detected. Such dependences are not explained by standard formulas for thin plates. On the basis of the calculations, an approach to estimate the coherence length ? has been proposed. The results of the calculations are consistent with experimental data and qualitative analysis of the calculations within GL theory.

  3. Strap grid tubular plate—a new positive plate for lead-acid batteries. Processes of residual sulphation of the positive plate

    NASA Astrophysics Data System (ADS)

    Pavlov, D.; Papazov, G.; Monahov, B.

    For almost a century now the tubular plate design has been based on cylindrical tubes and spines. The contact surface between the positive active mass (PAM) and the spine is small, which results in high polarisation of the plate at high discharge currents and low power output of the cell. In an attempt to eliminate these disadvantages, the shape of the tubes has been changed to flattened elliptic and the spines have been replaced by strap grids. The thickness of this new type of tubular plate, strap grid tubular plate (SGTP), is between 3 and 5 mm. Batteries with tubular plates of the new design (SGTP batteries) can be used in electric vehicle (EV) and photovoltaic (PV) system applications. This paper presents results of SGTP battery tests according to the European standards for EV, hybrid electric vehicle (HEV) and photovoltaic (PV) system batteries. SGTP batteries have a cycle life of 1000 ECE-15-EV cycles, 6000 ECE-HEV cycles and more than eight gross PV cycles. The optimum battery charge algorithm for VRLA batteries with strap grid tubular plates has been established and the mechanism of disintegration of the positive active mass has been disclosed. The following phenomena are responsible for the decline in capacity of the positive plates. First, when the PAM is built up of globules adhering closely to each other, a strong skeleton with thick aggregates (branches) with a membrane surface is formed. The surface layer of the branches impedes the access of H 2O and H 2SO 4 to their interior thus reducing the utilisation of the PAM. Besides, internal stresses are created in the aggregates, which cause them to crack. Secondly, when the PAM is built up of individual agglomerates with micropores in between, a porous mass with large surface is formed. The tubes keep the aggregates together and prolong the cycle life of the battery. During discharge, the contacts between the aggregates weaken and the capacity declines. Third, during discharge, the H 2SO 4 concentration in the pores of the plate inner layers (close to the straps) increases. In concentrated H 2SO 4 solution the solubility of PbSO 4 crystals decreases. This slows down the rate of oxidation of PbSO 4 to PbO 2. Some parts of the PbSO 4 crystals in the PAM of the charged plate remain unoxidised (residual sulphation). Thus, the capacity of the plate is lower. Strap corrosion is the phenomenon that may limit the cycle life of SGT plates.

  4. Thick DGP braneworlds

    SciTech Connect

    Quiros, Israel; Matos, Tonatiuh

    2008-11-15

    We study Dvali-Gabadadze-Porrati (DGP) braneworlds with finite thickness. In respect to the standard (thin) DGP Friedmann equation, finite thickness of the brane causes a subtle modification of the cosmological equations that can lead to significant physical consequences. The resulting cosmology is governed by two length scales which are associated with the brane thickness and with the crossover length, respectively. In this setup both early inflation and late-time acceleration of the expansion are a consequence of the 5D geometry. At early times, as well as at late times, 5D effects become dominant (gravity leaks into the extra dimension), while, at intermediate times, gravity is effectively 4D due to nontrivial physics occurring in standard (thin) DGP scenarios.

  5. 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.

  6. Investigation on mechanical properties of contemporary metallic bone plates: towards the development of composite bone plates.

    PubMed

    Hoque, M E; Zainal, N H; Syarif, J

    2008-07-01

    This study aims at investigating the mechanical properties of the contemporary metallic bone plates determining the effect of their length, width and thickness on the properties and compares with the composite bone plates. Three-points bending test was performed over the stainless steel plates of different length, width and thickness. The test results showed that different plates had different mechanical properties. However, the properties are still much higher than that of particular bones intended to be treated. Therefore, the reported findings strongly encourage developing composite bone plates with biocompatible polymers/fibers that would have modulated properties according to the requirements. PMID:19024999

  7. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to...

  8. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to...

  9. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to...

  10. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to...

  11. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to...

  12. An understanding of HSLA-65 plate steels

    NASA Astrophysics Data System (ADS)

    Sampath, K.

    2006-02-01

    HSLA-65 plate steels can be produced using one of five plate manufacturing techniques: normalizing, controlled rolling (CR), controlled rolling followed by accelerated cooling (CR-AC), direct quenching and tempering (DQT), or conventional quenching and tempering (Q&T). The HSLA-65 steels are characterized by low carbon content and low alloy content, and they exhibit a low carbon equivalent that allows improved plate weldability. These characteristics in turn (a) provide the steel plate with a refined microstructure that ensures high strength and toughness; (b) eliminate or substantially reduce the need for preheating during welding; (c) resist susceptibility to hydrogen-assisted cracking (HAC) in the weld heat affected zone (HAZ) when fusion (arc) welded using low heat-input conditions; and (d) depending on section thickness, facilitate high heat-input welding (about 2 kJ/mm) without significant loss of strength or toughness in the HAZ. However, application of this plate manufacturing process and of these controls produces significant differences in the metallurgical structure and range of mechanical properties of the HSLA-65 plate steels both among themselves and versus conventional higher strength steel (HSS) plates. For example, among the HSLA-65 plate steels, those produced by Q&T exhibit minimal variability in mechanical properties, especially in thicker plates. Besides variability in mechanical properties depending on plate thickness, the CR and CR-AC plate steels exhibit a relatively higher yield strength to ultimate tensile strength (YS/UTS) ratio than do DQT and Q&T steels. Such differences in processing and properties of HSLA-65 plate steels could potentially affect the selection and control of various secondary fabrication practices, including arc welding. Consequently, fabricators must exercise extreme caution when transferring allowable limits of certified secondary fabrication practices from one type of HSLA-65 plate steel to another, even for the same plate thickness.

  13. Preparation of thick molybdenum targets

    NASA Technical Reports Server (NTRS)

    Singh, J. J.

    1974-01-01

    Thick natural molybdenum deposits on nickel plated copper substrates were prepared by thermal decomposition of molybdenum hexacarbonyl vapors on a heated surface in an inert gas atmosphere. The molybdenum metal atoms are firmly bonded to the substrate atoms, thus providing an excellent thermal contact across the junction. Molybdenum targets thus prepared should be useful for internal bombardment in a cyclotron where thermal energy inputs can exceed 10 kW.

  14. 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.

  15. 24 CFR 3280.5 - Data plate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Data plate. 3280.5 Section 3280.5... MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS General § 3280.5 Data plate. Each manufactured home shall bear a data plate affixed in a permanent manner near the main electrical panel or other...

  16. 24 CFR 3280.5 - Data plate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Data plate. 3280.5 Section 3280.5... MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS General § 3280.5 Data plate. Each manufactured home shall bear a data plate affixed in a permanent manner near the main electrical panel or other...

  17. 24 CFR 3280.5 - Data plate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Data plate. 3280.5 Section 3280.5... MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS General § 3280.5 Data plate. Each manufactured home shall bear a data plate affixed in a permanent manner near the main electrical panel or other...

  18. 24 CFR 3280.5 - Data plate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Data plate. 3280.5 Section 3280.5... MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS General § 3280.5 Data plate. Each manufactured home shall bear a data plate affixed in a permanent manner near the main electrical panel or other...

  19. 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...

  20. Cadmium plating replacements

    SciTech Connect

    Nelson, M.J.; Groshart, E.C.

    1995-03-01

    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.

  1. 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.

  2. Standardized performance tests of collectors of solar thermal energy-a flat-plate collector with a single-tube serpentine flow distribution

    NASA Technical Reports Server (NTRS)

    Johnson, S.

    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 efficienty is correlated in terms of inlet temperature and flux level.

  3. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  4. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  5. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  6. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  7. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  8. Acoustic radiation from a point excited infinite bilaminar plate

    SciTech Connect

    Yum, S.H.

    1992-01-01

    Presented in this thesis is a refined model for plate deformation which allows for new types of thickness and extensional displacements not currently feasible in the classical or Timoshenko-Mindlin plate theories. An infinite bilaminar plate is fabricated in such a way that the two plates, made of different, isotropic, homogeneous materials, are perfectly bonded. A new mathematical model of the vibration of an infinite bilaminar plate has been obtained by using energy methods. The displacement field is based on symmetric and anti-symmetric displacement functions in both the thickness stretch and the thickness shear of each layer. From this model, the Timoshenko-Mindlin thick plate theory and the Bernoulli-Euler classic plate theory for a single plate can be recovered as special limiting cases. For this model, six-branched frequency-wavenumber spectrums of the single and the bilaminar plates are computed. This allows the introduction of suitable correction coefficients to correct the resulting frequency spectra so that they correspond to those of the exact elasticity theory. In addition, the relationship between frequency and critical angle spectra has been examined. The acoustic pressure directivity of a point force excited plate has been obtained, and the influence of structural damping on the directivity function of the plate is investigated.

  9. Low-energy impact response of composite and sandwich composite plates with piezoelectric sensory layers

    E-print Network

    Papadopoulos, Evangelos

    the global (impact force, plate deflection and electric potential) and through-thickness local (interfacial composite plates with piezoelectric sensory layers subjected to low-energy impact. The through-thickness­impactor structural system of minimum size (1 term per vibration mode for composite plates ­ 2 terms for sandwich

  10. 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.

  11. 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.

  12. Thru-thickness bending stress distribution at elevated temperatures 

    E-print Network

    Christian, Lee Conner

    2005-08-29

    temperatures were imported into the structural model. The plate thicknesses analyzed were one, one and a half, and two inches, assuming both 50 and 70 ksi yield strengths. To achieve a 90 degree six-inch radius bend the plate was bent in five separate locations...

  13. Comparison of 3M Petrifilm environmental Listeria plates against standard enrichment methods for the detection of Listeria monocytogenes of epidemiological significance from environmental surfaces.

    PubMed

    Nyachuba, D G; Donnelly, C W

    2007-11-01

    Environmental monitoring using sensitive methods for detection and elimination of harborage sites of Listeria monocytogenes is key to the control of this organism. The 3M Petrifilm Environmental Listeria (EL) Plate-a no enrichment method-was compared with the USDA/FSIS, modified USDA/FSIS (mUSDA), and ISO methods for detection/recovery of L. monocytogenes on 4 environmental surfaces (brick, dairy board, stainless steel, and epoxy resin). The efficacy of 3 sampling devices including the Microbial-Vac system((R)), environmental sponge, and 3M Quick swab in recovering epidemiologically significant strains of uninjured and sublethally injured L. monocytogenes from environmental surfaces was evaluated. Environmental surfaces were inoculated with Listeria to obtain final cell densities of approximately 10 to 100 CFU/100 cm(2). The surfaces were then sampled and processed. For all methods, percent recovery (% samples where Listeria was detected) was significantly higher (P < 0.05) for uninjured cells (75% to 100%) compared to injured cells (58.9% to 81.1%). The Petrifilm EL Plate method efficiently recovered both low level and injured Listeria populations from environmental test surfaces when used in conjunction with environmental sponge and the 3M Quick swab sampling. The mUSDA method was superior to all other methods for recovering both uninjured (100% recovery) and injured L. monocytogenes (80.8% to 81.1% recovery). Sponges and swabs were equally effective in recovering uninjured and injured Listeria and were significantly different (P < 0.05) from the Microbial-Vac system. The findings indicate that both mUSDA and Petrifilm EL Plate methods can be used for the detection of potentially injured Listeria on food processing environmental surfaces. PMID:18034727

  14. Acoustic emission localization in thin multi-layer plates using first-arrival determination

    NASA Astrophysics Data System (ADS)

    Sedlak, Petr; Hirose, Yuichiro; Enoki, Manabu

    2013-04-01

    In the case of thin plates, there exist two modes of propagation which travel at different velocities and exhibit dispersion characteristics. Techniques that are based on Gabor wavelet transform or cross-correlation technique are commonly used to locate acoustic emission (AE) events which occur in large plates. Due to side-edge reflections and short source-to-sensor distances, these techniques are not suitable for small plate-like specimens. If the thickness of the plate-like specimen is smaller than a specific value, the first-coming (extensional) mode will show non-dispersive behavior in AE frequency range. Under such a condition, the conventional localization method can be used for detecting first-arrival times on non-dispersive extensional mode. In previous paper, authors of the paper developed a first-arrival automatic determination technique based on Akaike information criterion (AIC) for thin metal plates. This paper compares this technique with another AIC approach, STA/LTA method (short-term average/long-term average) and a standard threshold-crossing technique. The comparative analysis includes blind tests, and is provided on four datasets recorded by a four-channel recording system. The three of four datasets were generated using two types of artificial AE sources (Hsu-Nielson source and laser impulse), while the fourth one contains real-measurement data. Each dataset corresponds to measurement made on a thin-plate specimen of a different material or geometry.

  15. Heat Treatment of Friction-Stir-Welded 7050 Aluminum Plates

    NASA Technical Reports Server (NTRS)

    Petter, George E.; Figert, John D.; Rybicki, Daniel J.; Burns, Timothy

    2006-01-01

    A method of heat treatment has been developed to reverse some of the deleterious effects of friction stir welding of plates of aluminum alloy 7050. This alloy is considered unweldable by arc and high-energy-density beam fusion welding processes. The alloy can be friction stir welded, but as-welded workpieces exhibit low ductility, low tensile and yield strengths, and low resistance to stress corrosion cracking. Heat treatment according to the present method increases tensile and yield strengths, and minimizes or eliminates stress corrosion cracking. It also increases ductility. This method of heat treatment is a superior alternative to a specification-required heat treatment that caused the formation of large columnar grains, which are undesired. Workpieces subjected to the prior heat treatment exhibited elongations <2 percent, and standard three-point bend specimens shattered. The development of the present heat treatment method was guided partly by the principles that (1) by minimizing grain sizes and relieving deformation stresses, one can minimize or eliminate stress corrosion cracking and (2) the key to maximizing strength and eliminating residual stresses is to perform post-weld solution heating for as long a time as possible while incurring little or no development of large columnar grains in friction stir weld nuggets. It is necessary to perform some of the solution heat treatment (to soften the alloy and improve machine welding parameters) before welding. The following is an example of thickness- dependent pre- and post-weld heat treatments according to the present method: For plates 0.270 in. (approx.6.86 mm) thick milled from plates 4.5 in. (114.3 mm) thick, perform pre-weld solution heating at 890 F (477 C) for 1 hour, then cool in air. After friction stir welding, perform solution heating for 10 minutes, quench, hold at room temperature for 96 hours, then age at 250 F (121 C) for 5 hours followed by 325 F (163 C) for 27 hours.

  16. Time-dependence in mantle convection models featuring dynamically evolving plates

    NASA Astrophysics Data System (ADS)

    Gait, A. D.; Lowman, J. P.

    2007-10-01

    We present the findings from a study of 2-D Cartesian geometry mantle convection simulations carried out to determine how plate velocities and the surface and basal heat flux respond to an evolving plate geometry. We model flow for periods equating to hundreds of millions of years and find that while calculations that feature fixed plate geometries exhibit regular reversals in plate motion, this behaviour is absent in models featuring evolving plate boundaries. However, simulations featuring evolving plate boundaries and plates with either a fixed-thickness or temporally varying thickness are highly time-dependent and their globally averaged mean plate velocities are higher than in simulations featuring static plate geometries. Our models featuring evolving plate geometries assume that (1) young plates override old plates with the velocity of the younger plate and (2) that symmetric seafloor spreading occurs at divergent plate boundaries. Plate velocities are dynamically determined in accord with a force-balance modelling approach and the plate velocities determine the dynamic evolution of the plate boundaries according to criteria (1) and (2), above. Plates in our calculations are highly viscous and are treated as rigid blocks for the purpose of determining whether they will break according to a yield stress criterion. The modelling of plate rifting means that both the number and mean size of the plates in our calculations are time-dependent. We focus on isolating the influence of plate thickness on time-dependent flows and examine the time-dependence of global plate velocities and mantle and core heat flow. In an initial study of unit aspect ratio models we find that there is a transition in the character of time-dependent behaviour as the model plate thickness is increased. Plates that are comparable in thickness to the mean thickness of the thermal boundary layer exhibit periodic reversals. Plates that are much thinner than the thermal boundary layer exhibit no reversals. Intermediate thickness plates reverse intermittently. In aspect ratio 12 calculations, we find that the mean global plate velocity can exhibit variations of more than a factor of two over periods of tens of millions of years. We also find that the mean surface velocity of the plates and the mean global heat flux rise and fall in tandem (although high frequency variations in the global velocity are not reflected in the heat flux time-series). In a simulation spanning almost 3 Gyr we observe several instances of surface heat flux fluctuations of 40-50 per cent occurring within periods of 75-200 Myr.

  17. TFSSRA - THICK FREQUENCY SELECTIVE SURFACE WITH RECTANGULAR APERTURES

    NASA Technical Reports Server (NTRS)

    Chen, J. C.

    1994-01-01

    Thick Frequency Selective Surface with Rectangular Apertures (TFSSRA) was developed to calculate the scattering parameters for a thick frequency selective surface with rectangular apertures on a skew grid at oblique angle of incidence. The method of moments is used to transform the integral equation into a matrix equation suitable for evaluation on a digital computer. TFSSRA predicts the reflection and transmission characteristics of a thick frequency selective surface for both TE and TM orthogonal linearly polarized plane waves. A model of a half-space infinite array is used in the analysis. A complete set of basis functions with unknown coefficients is developed for the waveguide region (waveguide modes) and for the free space region (Floquet modes) in order to represent the electromagnetic fields. To ensure the convergence of the solutions, the number of waveguide modes is adjustable. The method of moments is used to compute the unknown mode coefficients. Then, the scattering matrix of the half-space infinite array is calculated. Next, the reference plane of the scattering matrix is moved half a plate thickness in the negative z-direction, and a frequency selective surface of finite thickness is synthesized by positioning two plates of half-thickness back-to-back. The total scattering matrix is obtained by cascading the scattering matrices of the two half-space infinite arrays. TFSSRA is written in FORTRAN 77 with single precision. It has been successfully implemented on a Sun4 series computer running SunOS, an IBM PC compatible running MS-DOS, and a CRAY series computer running UNICOS, and should run on other systems with slight modifications. Double precision is recommended for running on a PC if many modes are used or if high accuracy is required. This package requires the LINPACK math library, which is included. TFSSRA requires 1Mb of RAM for execution. The standard distribution medium for this program is one 5.25 inch 360K MS-DOS format diskette. It is also available on a .25 inch streaming magnetic tape cartridge (Sun QIC-24) in UNIX tar format. This program was developed in 1992 and is a copyrighted work with all copyright vested in NASA.

  18. Buckling and vibration of orthotropic plates with an internal line hinge 

    E-print Network

    Gupta, Praveen R.

    2001-01-01

    This study presents analytical solutions for the buckling and vibration of uniaxially/biaxially loaded orthotropic thin and thick rectangular plates with an internal line hinge. The plate is taken to be flat, rectangular, with edges aligned along...

  19. 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...

  20. 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...

  1. 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...

  2. The Golosyiv plate archive digitisation

    NASA Astrophysics Data System (ADS)

    Sergeeva, T. P.; Sergeev, A. V.; Pakuliak, L. K.; Yatsenko, A. I.

    2007-08-01

    The plate archive of the Main Astronomical Observatory of the National Academy of Sciences of Ukraine (Golosyiv, Kyiv) includes about 85 000 plates which have been taken in various observational projects during 1950-2005. Among them are about 25 000 of direct northern sky area plates and more than 600 000 plates containing stellar, planetary and active solar formations spectra. Direct plates have a limiting magnitude of 14.0-16.0 mag. Since 2002 we have been organising the storage, safeguarding, cataloguing and digitization of the plate archive. The very initial task was to create the automated system for detection of astronomical objects and phenomena, search of optical counterparts in the directions of gamma-ray bursts, research of long period, flare and other variable stars, search and rediscovery of asteroids, comets and other Solar System bodies to improve the elements of their orbits, informational support of CCD observations and space projects, etc. To provide higher efficiency of this work we have prepared computer readable catalogues and database for 250 000 direct wide field plates. Now the catalogues have been adapted to Wide Field Plate Database (WFPDB) format and integrated into this world database. The next step will be adaptation of our catalogues, database and images to standards of the IVOA. Some magnitude and positional accuracy estimations for Golosyiv archive plates have been done. The photometric characteristics of the images of NGC 6913 cluster stars on two plates of the Golosyiv's double wide angle astrograph have been determined. Very good conformity of the photometric characteristics obtained with external accuracies of 0.13 and 0.15 mag. has been found. The investigation of positional accuracy have been made with A3± format fixed bed scanner (Microtek ScanMaker 9800XL TMA). It shows that the scanner has non-detectable systematic errors on the X-axis, and errors of ± 15 ?m on the Y-axis. The final positional errors are about ± 2 ?m (± 0 .2). have been obtained after corrections for systematic errors of the scanner and averaging four scans. So we may conclude that astrometric and photometric investigations may be done with precise commercial scanners. It will be necessary to scan plates at a minimum of two positions. We plan to scan the plate archive according to the priority of scientific tasks. Scanning will be done with an optical resolution of 1200 × 1200 dpi (pixel size 20 ?m), and with maximum amplitude resolution. The plate archive of MAO NASU is a unique well equipped instrument for conducting a range of astronomical investigations with a time scale of more than 50 yr.

  3. Pavement Thickness Design Parameter

    E-print Network

    Pavement Thickness Design Parameter Impacts 2012 Municipal Streets Seminar November 14, 2012 Paul D. Wiegand, P.E. #12;Pavement Thickness Design · How do cities decide how thick to build their pavements;Pavement Thickness Design · Correct answer ­ A data-based analysis! · Doesn't have to be difficult and time

  4. 40 CFR 426.40 - Applicability; description of the plate glass manufacturing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... plate glass manufacturing subcategory. 426.40 Section 426.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.40 Applicability; description of the plate...

  5. 40 CFR 426.40 - Applicability; description of the plate glass manufacturing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... plate glass manufacturing subcategory. 426.40 Section 426.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.40 Applicability; description of the plate...

  6. 40 CFR 426.40 - Applicability; description of the plate glass manufacturing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... plate glass manufacturing subcategory. 426.40 Section 426.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.40 Applicability; description of the plate...

  7. 40 CFR 426.40 - Applicability; description of the plate glass manufacturing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... plate glass manufacturing subcategory. 426.40 Section 426.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.40 Applicability; description of the plate...

  8. 40 CFR 426.40 - Applicability; description of the plate glass manufacturing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... plate glass manufacturing subcategory. 426.40 Section 426.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.40 Applicability; description of the plate...

  9. Analytical solution for free vibrations of simply supported transversally inextensible homogeneous rectangular plate

    E-print Network

    Batista, Milan

    2010-01-01

    In article, the exact solution of sinusoidal loaded simply supported elastic transversally inextensible rectangular plate is given. The expressions for displacement and stress components are derived and asymptotic expansion with respect to plate thickness are present. The frequency factors for plate thickness to width ratio 0.01, 0.1, 0.2 and 0.4 and various ratios of plate length to width are given.

  10. Analytical solution for free vibrations of simply supported transversally inextensible homogeneous rectangular plate

    E-print Network

    Milan Batista

    2010-07-16

    In article, the exact solution of sinusoidal loaded simply supported elastic transversally inextensible rectangular plate is given. The expressions for displacement and stress components are derived and asymptotic expansion with respect to plate thickness are present. The frequency factors for plate thickness to width ratio 0.01, 0.1, 0.2 and 0.4 and various ratios of plate length to width are given.

  11. An evaluation of displacement-based finite element models used for free vibration analysis of homogeneous and composite plates

    NASA Astrophysics Data System (ADS)

    Burlayenko, V. N.; Altenbach, H.; Sadowski, T.

    2015-12-01

    The finite element vibration analysis of plates has become one of the classical problems over the past several decades. Different finite element plate models based on classical, standard and improved shear deformable plate theories, three-dimensional elasticity equations or their combinations have been developed. The ability and accuracy of each such model can be established by validating it against analytical models, if it is possible, or other numerical models. In this paper, a comparative study of different plate finite element models used for the free vibration analysis of homogeneous isotropic and anisotropic, composite laminated and sandwich thin and thick plates with different boundary conditions is presented. The aim of the study is to find out the weaknesses and strengths of each model used and to pick out their interchangeability for the finite element calculations. For comparisons, the plate models based on classical and first-order shear deformation theories within the framework of both single-layer and layer-wise concept and three-dimensional theory of elasticity are used. The models are created using the finite element package ABAQUSTM. Natural frequencies obtained by the authors are compared with results known in the literature from different analytical or approximate solutions and, then, the correlation between them is discussed in detail. At the end, conclusions are drawn concerning the utility of each model considered for vibration predictions of plates.

  12. Growth Plate Fractures

    MedlinePLUS

    .org Growth Plate Fractures Page ( 1 ) The bones of children and adults share many of the same risks for injury. But because they ... to a unique injury called a growth plate fracture. Growth plates are areas of cartilage located near ...

  13. Natural frequencies of twisted rotating plates

    NASA Technical Reports Server (NTRS)

    Ramamurti, V.; Kielb, R.

    1984-01-01

    A detailed comparison is presented of the predicted eigenfrequencies of twisted rotating plates as obtained by using two different shape functions. Primarily, rotating twisted plates of two different aspect ratios and two different thickness ratios are considered. The effects of rotation are included by using a 'stress smoothing' technique when calculating the augmented stiffness matrix. In addition, the effects of Coriolis acceleration, contributions from membrane behavior, setting angle and sweep angle are considered. The effects of geometric nonlinearity are briefly discussed. Finally, results of a brief study of cambered plates are presented.

  14. Large Time Existence for Thin Vibrating Plates

    E-print Network

    Abels, H; Müller, S

    2009-01-01

    We construct strong solutions for a nonlinear wave equation for a thin vibrating plate described by nonlinear elastodynamics. For sufficiently small thickness we obtain existence of strong solutions for large times under appropriate scaling of the initial values such that the limit system as $h\\to 0$ is either the nonlinear von K\\'arm\\'an plate equation or the linear fourth order Germain-Lagrange equation. In the case of the linear Germain-Lagrange equation we even obtain a convergence rate of the three-dimensional solution to the solution of the two-dimensional linear plate equation.

  15. Temperature-dependent creep buckling of plates

    NASA Technical Reports Server (NTRS)

    Ross, D. A.; Berke, L.

    1981-01-01

    Time-dependent lateral deflection of flat rectangular plates is predicted by the Norton-Bailey (Norton 1929, Bailey 1935) power law for material creep. The plates have a through-thickness steady-state temperature distribution, and the effects are considered by using Maxwell's law to modify the power creep law. Equations are derived for creep exponents of 3 and 5, using the sandwich plate element to predict creep buckling of plates. Predictions of creep buckling with a temperature variation between the inner and outer plate surfaces are found to be somewhat dependent on the creep buckling relationship assumed. When significant scatter justifies a variation in the creep constants up to an order of magnitude, discrepancies in predictions using the two exponents are reasonable, and for one engineering material, the predictions have the same degree of agreement with experimental data as have the respective creep laws.

  16. ieee transactions on ultrasonics, ferroelectrics, and frequency control, vol. 53, no. 2, february 2006 349 Torsional Vibrations of Circular Elastic Plates

    E-print Network

    Huang, Rui

    2006 349 Torsional Vibrations of Circular Elastic Plates with Thickness Steps Min K. Kang, Rui Huang, the thickness-shear vibrations can be con- fined in the center portion of the plate, which improves in isotropic elastic plates. The exact solu- tions for torsional vibrations in circular and annular plates

  17. High order shear horizontal modes for minimum remnant thickness.

    PubMed

    Belanger, Pierre

    2014-04-01

    Thickness mapping in aging structures suffering from corrosion is challenging especially when the structure is only partially accessible. In plates the high order shear horizontal guided wave modes all have a cutoff frequency thickness product below which they cannot propagate. This property is potentially attractive to estimate the minimum remnant thickness between two transducers. When using a source and a sensor array it is possible to control the number of modes being excited and the size of the region interrogated by the technique. Finite element simulations were used to show that by exciting multiple guided wave modes simultaneously and identifying which modes are received by a sensor array it is possible to estimate the minimum remaining thickness along the propagation path. Initial experimental results showed excellent agreement with the finite element simulations when the plate is uniform and with a thickness reduction between the source and the sensor arrays the minimum remnant thickness was underestimated by approximately 20%. PMID:24472432

  18. Steady-state heat conduction in multilayered composite plates and shells

    NASA Technical Reports Server (NTRS)

    Noor, A. K.; Burton, W. S.

    1991-01-01

    A study is made of a predictor-corrector procedure for the accurate determination of the temperature and heat flux distributions in thick multilayered composite plates and shells. A linear through-the-thickness temperature distribution is used in the predictor phase. The functional dependence of temperature on the thickness coordinate is then calculated a posteriori and used in the corrector phase. Extensive numerical results are presented for linear steady-state heat conduction problems, showing the effects of variation in the geometric and lamination parameters on the accuracy of the thermal response predictions of the predictor-corrector approach. Both antisymmetrically laminated anisotropic plates and multilayered orthotropic cylinders are considered. The solutions are assumed to be periodic in the surface coordinates. For each problem the standard of comparison is taken to be the analytic three-dimensional solution based on treating each layer as a homogeneous anisotropic medium. The potential of the predictor-corrector approach for predicting the thermal response of multilayered plates and shells with complicated geometry is discussed.

  19. 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.

  20. Reference Phase of Fresnel Zone Plates

    E-print Network

    G. W. Webb

    2003-02-28

    The standard zone plate assumes that the shortest ray connecting a radiation source and a detection point has a phase of 0 deg thereby defining a reference phase. Here we examine the experimental consequences of varying this reference phase from 0 deg to 360 deg. It is concluded that reference phase is an intrinsic and useful property of zone plates.

  1. 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...

  2. The primary resonance of laminated piezoelectric rectangular plates.

    PubMed

    Zhao, Shuai; Shi, Zhifei; Xiang, Hongjun

    2009-11-01

    Based on Hamilton's principle and the Rayleigh-Ritz method, a model of a nonlinear dynamic laminated piezoelectric rectangular plate was established, and the governing equations were derived and solved for both the thin-plate and thick-plate models. In the present investigation, the nonlinear constitutive relations of piezoelectric materials were considered and the effects of the nonlinearity on the response of the plate were discovered. The primary resonance of rectangular plate is investigated with the use of the method of multiple scales. The results obtained in the present paper agree very well with the experiment results. PMID:19942538

  3. Omnidirectional broadband insulating device for flexural waves in thin plates

    E-print Network

    Climente, Alfonso; Sánchez-Dehesa, José

    2013-01-01

    This work presents a gradient index device for insulating from vibrations a circular area of a thin plate. The gradient of the refractive index is achieved by locally changing the thickness of the plate, exploiting in this way the thickness-dependence of the dispersion relation of flexural waves in thin plates. A well-like thickness profile in an annular region of the plate is used to mimic the combination of an attractive and repulsive potentials, focusing waves at its bottom and dissipating them by means of a properly designed absorptive layer placed on top of the plate. The central area is therefore isolated from vibrations while they are dissipated at the bottom of the well. Simulations have been done using the multilayer multiple scattering method and the results prove their broadband efficiency and omnidirectional properties.

  4. MTR plates modeling with MAIA

    SciTech Connect

    Marelle, V.; Dubois, S.; Ripert, M.; Noirot, J.

    2008-07-15

    MAIA is a thermo-mechanical code dedicated to the modeling of MTR fuel plates. The main physical phenomena modeled in the code are the cladding oxidation, the interaction between fuel and Al-matrix, the swelling due to fission products and the Al/fuel particles interaction. The creeping of the plate can be modeled in the mechanical calculation. MAIA has been validated on U-Mo dispersion fuel experiments such as IRIS 1 and 2 and FUTURE. The results are in rather good agreement with post-irradiation examinations. MAIA can also be used to calculate in-pile behavior of U{sub 3}Si{sub 2} plates as in the SHARE experiment irradiated in the SCK/Mol BR2 reactor. The main outputs given by MAIA throughout the irradiation are temperatures, cladding oxidation thickness, interaction thickness, volume fraction of meat constituents, swelling, displacements, strains and stresses. MAIA is originally a two-dimensional code but a three-dimensional version is currently under development. (author)

  5. Volcano spacing and plate rigidity

    SciTech Connect

    Brink, U. )

    1991-04-01

    In-plane stresses, which accompany the flexural deformation of the lithosphere under the load adjacent volcanoes, may govern the spacing of volcanoes in hotspot provinces. Specifically, compressive stresses in the vicinity of a volcano prevent new upwelling in this area, forcing a new volcano to develop at a minimum distance that is equal to the distance in which the radial stresses change from compressional to tensile (the inflection point). If a volcano is modeled as a point load on a thin elastic plate, then the distance to the inflection point is proportional to the thickness of the plate to the power of 3/4. Compilation of volcano spacing in seven volcanic groups in East Africa and seven volcanic groups of oceanic hotspots shows significant correlation with the elastic thickness of the plate and matches the calculated distance to the inflection point. In contrast, volcano spacing in island arcs and over subduction zones is fairly uniform and is much larger than predicted by the distance to the inflection point, reflecting differences in the geometry of the source and the upwelling areas.

  6. 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.

  7. 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.

  8. The vibration by analogy of certain trusses, beams and plates 

    E-print Network

    Thompson, Lee Price

    1953-01-01

    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. 49 CFR 179.200-6 - Thickness of plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Where: d = Inside diameter in inches; E = 0.9 Welded joint efficiency; except E=1.0 for seamless heads....9 Welded joint efficiency; except E=1.0 for seamless heads; P = Minimum required bursting pressure...: EC13NO91.034 Where: E = 0.9 Welded joint efficiency; except E=1.0 for seamless heads; L = Main...

  10. Plate Tectonics, Geographical Information System, paleogeography

    Energy Science and Technology Software Center (ESTSC)

    2002-05-24

    The PaleoX.framwork is a dynamically linked/loaded framework for Cocoa applications. The primary goal of this library is to standardize several elements used for working with paleogeographic data. This includes objects designed to organize information for tectonic plates, including maps, rotation objects, plate names, and designations. In addition, PaleoX provides object-oriented solutions for handling standard paleogeographic file formats from the PALEOMAP Project.

  11. 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...

  12. 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.

  13. Three-dimensional estimate of the lithospheric effective elastic thickness of the Line ridge

    NASA Astrophysics Data System (ADS)

    Hu, Minzhang; Li, Jiancheng; Jin, Taoyong; Xu, Xinyu; Xing, Lelin; Shen, Chongyang; Li, Hui

    2015-09-01

    Using a new bathymetry grid formed with vertical gravity gradient anomalies and ship soundings (BAT_VGG), a 1° × 1° lithospheric effective elastic thickness (Te) grid of the Line ridge was calculated with the moving window admittance technique. As a comparison, both the GEBCO_08 and SIO V15.1 bathymetry datasets were used to calculate Te as well. The results show that BAT_VGG is suitable for the calculation of lithospheric effective elastic thickness. The lithospheric effective elastic thickness of the Line ridge is shown to be low, in the range of 5.5-13 km, with an average of 8 km and a standard deviation of 1.3 km. Using the plate cooling model as a reference, most of the effective elastic thicknesses are controlled by the 150-300 °C isotherm. Seamounts are primarily present in two zones, with lithospheric ages of 20-35 Ma and 40-60 Ma, at the time of loading. Unlike the Hawaiian-Emperor chain, the lithospheric effective elastic thickness of the Line ridge does not change monotonously. The tectonic setting of the Line ridge is discussed in detail based on our Te results and the seamount ages collected from the literature. The results show that thermal and fracture activities must have played an important role in the origin and evolution of the ridge.

  14. The Gold-plated mode revisited: sin(2 beta) and B^0 to J/Psi K_S in the Standard Model

    E-print Network

    Heike Boos; Thomas Mannel; Jurgen Reuter

    2004-03-08

    We study the corrections to the determination of sin(2 beta) from the time dependent CP asymmetry of B^0 to J/Psi K_S which arise in the standard model. Although a precise prediction of these corrections is not possible we find that they are indeed extremely small, of the order of less than a per mil of the observed value. This means in turn that any deviation visible at the B factories will be a clear signal for new physics.

  15. Three-dimensional dynamic models of subducting plate-overriding plate-upper mantle interaction

    NASA Astrophysics Data System (ADS)

    Meyer, C.; Schellart, W. P.

    2013-02-01

    We present fully dynamic generic three-dimensional laboratory models of progressive subduction with an overriding plate and a weak subduction zone interface. Overriding plate thickness (TOP) is varied systematically (in the range 0-2.5 cm scaling to 0-125 km) to investigate its effect on subduction kinematics and overriding plate deformation. The general pattern of subduction is the same for all models with slab draping on the 670 km discontinuity, comparable slab dip angles, trench retreat, trenchward subducting plate motion, and a concave trench curvature. The narrow slab models only show overriding plate extension. Subduction partitioning (vSP? / (vSP? + vT?)) increases with increasing TOP, where trenchward subducting plate motion (vSP?) increases at the expense of trench retreat (vT?). This results from an increase in trench suction force with increasing TOP, which retards trench retreat. An increase in TOP also corresponds to a decrease in overriding plate extension and curvature because a thicker overriding plate provides more resistance to deform. Overriding plate extension is maximum at a scaled distance of ~200-400 km from the trench, not at the trench, suggesting that basal shear tractions resulting from mantle flow below the overriding plate primarily drive extension rather than deviatoric tensional normal stresses at the subduction zone interface. The force that drives overriding plate extension is 5%-11% of the slab negative buoyancy force. The models show a positive correlation between vT? and overriding plate extension rate, in agreement with observations. The results suggest that slab rollback and associated toroidal mantle flow drive overriding plate extension and backarc basin formation.

  16. How the interior viscosity structure of a terrestrial planet controls plate driving forces and plate tectonics

    NASA Astrophysics Data System (ADS)

    Hoeink, T.; Lenardic, A.; Jellinek, M.; Richards, M. A.

    2011-12-01

    One of the fundamental unresolved problems in Earth and planetary science is the generation of plate tectonics from mantle convection. Important achievements can be made when considering rheological properties in the context of mantle convection dynamics. Among these milestones are (1) a deeper understanding of the balance of forces that drive and resist plate motion and (2) the dynamic generation of narrow plate boundaries (that lead to a piecewise continuous surface velocity distribution). Extending classic plate-tectonic theory we predict a plate driving force due to viscous coupling at the base of the plate from fast flow in the asthenosphere. Flow in the asthenosphere is due to shear-driven contributions from an overriding plate and due to additional pressure-driven contributions. We use scaling analysis to show that the extent to which this additional plate-driving force contributes to plate motions depends on the lateral dimension of plates and on the relative viscosities and thicknesses of lithosphere and asthenosphere. Whereas slab-pull forces always govern the motions of plates with a lateral extent greater than the mantle depth, asthenosphere-drive forces can be relatively more important for smaller (shorter wavelength) plates, large relative asthenosphere viscosities or large asthenosphere thicknesses. Published plate velocities, tomographic images and age-binned mean shear wave velocity anomaly data allow us to estimate the relative contributions of slab-pull and asthenosphere-drive forces driving the motions of the Atlantic and Pacific plates. At the global scale of terrestrial planets, we use 3D spherical shell simulations of mantle convection with temperature-, depth- and stress dependent rheology to demonstrate that a thin low-viscosity layer (asthenosphere) governs convective stresses imparted to the lithosphere. We find, consistent with theoretical predictions, that convective stresses increase for thinner asthenospheres. This result might eliminate the need for special weakening mechanisms to generate plate tectonics from mantle convection. Our results elucidate the role of the asthenosphere for plate tectonics on Earth, and also provide insights into the differences in tectonic styles between Earth and Venus.

  17. 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

    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.

  18. Sensitivity, Specificity, and Predictive Values of Three Salmonella Rapid Detection Kits Using Fresh and Frozen Poultry Environmental Samples versus Those of Standard Plating

    PubMed Central

    Peplow, Melissa O.; Correa-Prisant, Maria; Stebbins, Martha E.; Jones, Frank; Davies, Peter

    1999-01-01

    To reduce human exposure to Salmonella spp. in poultry products, broiler chicken flocks have been tested by culture methods. Since the standard techniques may take 3 to 5 days, rapid detection methods have been developed. In this study we tested the performance of three rapid tests originally developed for food samples by using environmental samples obtained from poultry houses. These rapid tests were Reveal, an enzyme-linked immunosorbent assay from Neogen Corp.; BIND, a bacterial ice nucleation detection method from Idetek Corp.; and a filter monitor method from Future Medical Technologies, Inc. For the standard culture, brilliant green with novabiocin and xylose–lysine–tergitol-4 agar were used for presumptive identification, and identities were confirmed by using poly-O antisera. Environmental samples were collected from farms belonging to an integrated poultry company prior to chick placement and 1 week before slaughter. Sensitivities, specificities, and predictive values with 95% confidence intervals were calculated. Statistical differences were determined by using McNemar’s chi square test. The sensitivities of the different tests were not stable, varying widely between sample times, and were affected by freezing of the samples. All of the rapid tests had low sensitivities, which led to many false-negative results. All tests were able to detect Salmonella spp. at a concentration of 10 CFU/ml in at least one of four trials. The BIND and Reveal tests were simple to use with multiple samples and reduced laboratory time by up to 1 day. Based on our results, we do not recommend that any of these rapid tests, in their present state of development, be utilized with environmental samples collected with drag swabs. PMID:10049863

  19. Design parameters of stainless steel plates for maximizing high frequency ultrasound wave transmission.

    PubMed

    Michaud, Mark; Leong, Thomas; Swiergon, Piotr; Juliano, Pablo; Knoerzer, Kai

    2015-09-01

    This work validated, in a higher frequency range, the theoretical predictions made by Boyle around 1930, which state that the optimal transmission of sound pressure through a metal plate occurs when the plate thickness equals a multiple of half the wavelength of the sound wave. Several reactor design parameters influencing the transmission of high frequency ultrasonic waves through a stainless steel plate were examined. The transmission properties of steel plates of various thicknesses (1-7 mm) were studied for frequencies ranging from 400 kHz to 2 MHz and at different distances between plates and transducers. It was shown that transmission of sound pressure through a steel plate showed high dependence of the thickness of the plate to the frequency of the sound wave (thickness ratio). Maximum sound pressure transmission of ? 60% of the incident pressure was observed when the ratio of the plate thickness to the applied frequency was a multiple of a half wavelength (2 MHz, 6mm stainless steel plate). In contrast, minimal sound pressure transmission (? 10-20%) was measured for thickness ratios that were not a multiple of a half wavelength. Furthermore, the attenuation of the sound pressure in the transmission region was also investigated. As expected, it was confirmed that higher frequencies have more pronounced sound pressure attenuation than lower frequencies. The spatial distribution of the sound pressure transmitted through the plate characterized by sonochemiluminescence measurements using luminol emission, supports the validity of the pressure measurements in this study. PMID:25637292

  20. The nonlinear transient response of thin, rectangular elastic plates

    NASA Technical Reports Server (NTRS)

    Rajagopal, G.; Lowery, R. L.

    1976-01-01

    The results of experiments and theoretical analysis of the nonlinear, transient response of thin, rectangular, elastic, simply supported plates are presented. In the experiments, a plane wave tube with a special pulse generator at one end and a thin glass plate mounted at the other end was used to subject the glass plate to pressure pulses of different magnitudes. Whole-field measurements of the response of the plate were obtained by the reflected moire grid technique. The largest ratio of center deflection to thickness of the plate during the experiments was 5.6. The theoretical response of the glass plate to the pressure pulses was computed by solving the von Karman equations governing large deflections in elastic plates by two methods - (1) the finite-difference method, and (2) Galerkin's method. Good agreement was found between theoretically predicted and experimentally measured response.

  1. CMUT Fabrication Based On A Thick Buried Oxide Layer.

    PubMed

    Kupnik, Mario; Vaithilingam, Srikant; Torashima, Kazutoshi; Wygant, Ira O; Khuri-Yakub, Butrus T

    2010-10-01

    We introduce a versatile fabrication process for direct wafer-bonded CMUTs. The objective is a flexible fabrication platform for single element transducers, 1D and 2D arrays, and reconfigurable arrays. The main process features are: A low number of litho masks (five for a fully populated 2D array); a simple fabrication sequence on standard MEMS tools without complicated wafer handling (carrier wafers); an improved device reliability; a wide design space in terms of operation frequency and geometric parameters (cell diameter, gap height, effective insulation layer thickness); and a continuous front face of the transducer (CMUT plate) that is connected to ground (shielding for good SNR and human safety in medical applications). All of this is achieved by connecting the hot electrodes individually through a thick buried oxide layer, i.e. from the handle layer of an SOI substrate to silicon electrodes located in each CMUT cell built in the device layer. Vertical insulation trenches are used to isolate these silicon electrodes from the rest of the substrate. Thus, the high electric field is only present where required - in the evacuated gap region of the device and not in the insulation layer of the post region. Array elements (1D and 2D) are simply defined be etching insulation trenches into the handle wafer of the SOI substrate. PMID:22685377

  2. CMUT Fabrication Based On A Thick Buried Oxide Layer

    PubMed Central

    Kupnik, Mario; Vaithilingam, Srikant; Torashima, Kazutoshi; Wygant, Ira O.; Khuri-Yakub, Butrus T.

    2010-01-01

    We introduce a versatile fabrication process for direct wafer-bonded CMUTs. The objective is a flexible fabrication platform for single element transducers, 1D and 2D arrays, and reconfigurable arrays. The main process features are: A low number of litho masks (five for a fully populated 2D array); a simple fabrication sequence on standard MEMS tools without complicated wafer handling (carrier wafers); an improved device reliability; a wide design space in terms of operation frequency and geometric parameters (cell diameter, gap height, effective insulation layer thickness); and a continuous front face of the transducer (CMUT plate) that is connected to ground (shielding for good SNR and human safety in medical applications). All of this is achieved by connecting the hot electrodes individually through a thick buried oxide layer, i.e. from the handle layer of an SOI substrate to silicon electrodes located in each CMUT cell built in the device layer. Vertical insulation trenches are used to isolate these silicon electrodes from the rest of the substrate. Thus, the high electric field is only present where required – in the evacuated gap region of the device and not in the insulation layer of the post region. Array elements (1D and 2D) are simply defined be etching insulation trenches into the handle wafer of the SOI substrate. PMID:22685377

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

    SciTech Connect

    Qatu, M.S.

    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.

  4. 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.

  5. 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.

  6. 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.

  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. Nonlinear free vibration analysis of composite plates with material uncertainties: A Monte Carlo simulation approach

    NASA Astrophysics Data System (ADS)

    Singh, B. N.; Bisht, A. K. S.; Pandit, M. K.; Shukla, K. K.

    2009-07-01

    In this paper, the effects of dispersion in material properties on free vibration response of composite plates with geometric nonlinearity in von-Karman sense are investigated. The higher order shear deformation theory is employed for the study reported here. An efficient C0 finite element formulation is developed for the analysis. Using Monte Carlo simulation, the second order statistics i.e., mean and standard deviation of the nonlinear free vibration response of the composite laminates are obtained for different thickness and amplitude ratios. The input statistics (mean and variance) of the material property are assumed to be known as a priori. The computed results demonstrate the influence of the variations in the material properties and amplitudes on the nonlinear free vibration response of the composite plates. The results are compared with those available in the literature.

  9. Experimental Investigation of Light-Gauge Steel Plate Shear Jeffrey W. Berman1

    E-print Network

    Bruneau, Michel

    ) and a third using a corrugated infill plate (thickness of 0.7 mm). Connection of the infill plates to the boundary frames is achieved through the use of bolts in combination with industrial strength epoxy or welds a corrugated infill plate, achieve significant ductility and energy dissipation while minimizing the demands

  10. Approximation of the vibration modes of a plate by Reissner-Mindlin equations

    E-print Network

    Rodríguez, Rodolfo

    Approximation of the vibration modes of a plate by Reissner-Mindlin equations R. G. Dur´an, L with the approximation of the vibration modes of a plate modelled by the Reissner-Mindlin equations. It is well known assumptions, these estimates are valid with constants independent of the plate thickness. The optimal double

  11. Finite element computation of the vibrations of a plate-fluid system with interface damping

    E-print Network

    Rodríguez, Rodolfo

    Finite element computation of the vibrations of a plate-fluid system with interface damping Alfredo the thickness of the plate becomes small. Finally the computed resonance frequencies are compared with those excitation. The system consists of an acoustic fluid and a plate, with a thin layer of a noise damping

  12. Approximation of the vibration modes of a plate by ReissnerMindlin equations

    E-print Network

    Duran, Ricardo

    Approximation of the vibration modes of a plate by Reissner­Mindlin equations R. G. Dur'an, \\Lambda with the approximation of the vibration modes of a plate modelled by the Reissner­Mindlin equations. It is well known assumptions, these estimates are valid with constants independent of the plate thickness. The optimal double

  13. Dynamics of Elastic Defects in Thin Plates Yoel Forterre,1,2

    E-print Network

    Forterre, Yoël

    -sheet. This highly nonlinear dynamics strongly contrast with the linear response to small vibrations in plates being connected to its wavelength by f (h/2 )(E/)1/2 , where h is the thickness of the plate, E itsDynamics of Elastic Defects in Thin Plates Yo¨el Forterre,1,2 Denis Richard, 1 L. Mahadevan 1 1

  14. 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.

  15. MyPlate

    MedlinePLUS

    ... a Budget Create a Grocery Game Plan Shop Smart to Fill Your Cart Prepare Healthy Meals Sample 2-Week Menus Resources for Professionals 10 Tips ... are here Home / MyPlate MyPlate Error message Notice : Undefined index: title ...

  16. Accelerated plate tectonics.

    PubMed

    Anderson, D L

    1975-03-21

    The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence. PMID:17799689

  17. Defects and boundary layers in non-Euclidean plates

    E-print Network

    Gemmer, John

    2012-01-01

    We investigate the behaviour of non-Euclidean plates with constant negative Gaussian curvature using the F\\"oppl-von K\\'arm\\'an reduced theory of elasticity. Motivated by recent experimental results, we focus on annuli with a periodic profile. We prove rigorous upper and lower bounds for the elastic energy that scales like the thickness squared. We also investigate the scaling with thickness of boundary layers where the stretching energy is concentrated with decreasing thickness.

  18. On the strain energy of laminated composite plates

    NASA Technical Reports Server (NTRS)

    Atilgan, Ali R.; Hodges, Dewey H.

    1991-01-01

    The present effort to obtain the asymptotically correct form of the strain energy in inhomogeneous laminated composite plates proceeds from the geometrically nonlinear elastic theory-based three-dimensional strain energy by decomposing the nonlinear three-dimensional problem into a linear, through-the-thickness analysis and a nonlinear, two-dimensional analysis analyzing plate formation. Attention is given to the case in which each lamina exhibits material symmetry about its middle surface, deriving closed-form analytical expressions for the plate elastic constants and the displacement and strain distributions through the plate's thickness. Despite the simplicity of the plate strain energy's form, there are no restrictions on the magnitudes of displacement and rotation measures.

  19. Planet Earth: Plate Tectonics

    E-print Network

    Watts, A. B. "Tony"

    Planet Earth: Plate Tectonics Recommended Books: An Introduction to Our Dynamic Planet (ODP), 2007, ice and sediment for long periods of geological time (>105 a). · Controlled and passive (e, Problem sets etc Lecture 1: Plate Mechanics and Kinematics The Earth comprises 7 major plates and a number

  20. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, B.S.; Lauf, R.J.

    1995-09-19

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors. 8 figs.

  1. 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…

  2. Linear versus nonlinear theories for laminated composite plates and shells

    SciTech Connect

    Qatu, M.S.

    1995-11-01

    Linear and nonlinear shear-deformation theories for laminated composite plates and shells are discussed in this paper. The emphasis here is on the range of validity for each class of theories. The finite element method is used to determine the maximum stresses for a wide range of statically loaded plate and shell panels with various thickness ratios. This paper concludes that for the vast majority of composite materials and for moderately thick plates and shells, stresses normally reach the maximum allowable stress before nonlinear terms can become important. This has been demonstrated by showing that for the limiting case of shear deformation theories (in which the minimum span length (or radius) to thickness ratio is 20), the material usually fails before the maximum deflection reaches the magnitude of the thickness (where nonlinear terms start to become significant).

  3. 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; Akiyama, Masayuki; Hasinger, Günther; Miyaji, Takamitsu; Watson, Michael G.

    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.

  4. 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.

  5. 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.

  6. Screen test for cadmium and nickel plates

    NASA Technical Reports Server (NTRS)

    Phan, Angie H.; Zimmerman, Albert H.

    1994-01-01

    A new procedure is described which was recently developed to quantify loading uniformity of nickel and cadmium plates and to screen finished electrodes prior to cell assembly. The technique utilizes the initial solubility rates of the active material in a standard chemical deloading solution at fixed conditions. The method can provide a reproducible indication of plate loading uniformity in situations where high surface loading limits the free flow of deloading solution into the internal porosity of the sinter plate. A preliminary study indicates that 'good' cell performance is associated with higher deloading rates.

  7. Computerized Ultrasonic Testing System (CUTS) for in-process thickness determination

    NASA Technical Reports Server (NTRS)

    Frankel, J.; Doxbeck, M.; Schroeder, S. C.; Abbate, A.

    1994-01-01

    A Computerized Ultrasonic Testing System (CUTS) was developed to measure, in real-time, the rate of deposition and thickness of chromium plated on the inside of thick steel tubes. The measurements are made from the outside of the tubes with the ultrasonic pulse-echo technique. The resolution of the system is 2.5 micron. (0.0001 in.) and the accuracy is better than 10 micron (0.0004 in.). The thickness is measured using six transducers mounted at different locations on the tube. In addition, two transducers are mounted on two reference standards, thereby allowing the system to be continuously calibrated. The tube temperature varies during the process, thus the input from eight thermocouples, located at the measurement sites, is used to calculate and compensate for the change in return time of the ultrasonic echo due to the temperature dependence of the sound velocity. CUTS is applicable to any commercial process where real-time change of thickness of a sample has to be known, with the advantage of facilitating increased efficiency and of improving process control.

  8. 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.

  9. Variations in elastic thickness and flexure of the Maracaibo block

    NASA Astrophysics Data System (ADS)

    Arnaiz-Rodríguez, Mariano S.; Audemard, Franck

    2014-12-01

    We estimate the lateral variations of the elastic thickness of the Maracaibo block with a 3D numerical approach by using centered finite differences. 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) with variable thickness (or elastic thickness for this particular case). An initial plate-load model is built and is iteratively modified to fit the general basement configuration and gravity data. The final result is an elastic thickness map that covers the Maracaibo block and the surrounding sections of the South American plate. It shows that the elastic thickness ranges from 30 km to 18 km with a mean value of 23.6 km and a mode of 26 km. The largest elastic thickness values are associated with the location of the Santa Marta Mountains and the Barinas Apure Basin, while the smallest ones with the Mérida Andes-Maracaibo Basin flexural system. The current basement configuration within the Maracaibo basin, formed as a result of its geodynamic evolution, has affected the mechanical properties of the Maracaibo block near the current Mérida Andes position. The load of the Perijá Range is compensated by a complex stress tensor, and that of the Santa Marta Mountains does not have an isostatic root as it is held by a relatively strong lithosphere.

  10. Origami of thick panels

    NASA Astrophysics Data System (ADS)

    Chen, Yan; Peng, Rui; You, Zhong

    2015-07-01

    Origami patterns, including the rigid origami patterns in which flat inflexible sheets are joined by creases, are primarily created for zero-thickness sheets. In order to apply them to fold structures such as roofs, solar panels, and space mirrors, for which thickness cannot be disregarded, various methods have been suggested. However, they generally involve adding materials to or offsetting panels away from the idealized sheet without altering the kinematic model used to simulate folding. We develop a comprehensive kinematic synthesis for rigid origami of thick panels that differs from the existing kinematic model but is capable of reproducing motions identical to that of zero-thickness origami. The approach, proven to be effective for typical origami, can be readily applied to fold real engineering structures.

  11. Growth of large KDP crystals in the form of plates

    SciTech Connect

    Beriot, E; Tatartchenko, V

    1998-05-01

    This paper suggests a new technique of growth-oriented KDP crystals in the form of plates. The technique includes: using small oriented seeds spaced between two parallel platforms with a rapid growth of crystals between these two platforms, in a tank containing a KDP solution. As a result, crystals in the form of plates can be obtained. The thickness of the crystal plate depends on the distance between platforms. The horizontal dimensions of the plate depend on the volume of solution and the diameter of the platforms. The orientation of the plates are defined by the orientation of the seed. KDP crystals in the form of plates of two orientations are grown. The peculiarities of morphology and some characteristics of crystals are discussed.

  12. 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.

  13. Vibrations of rectangular plates with moderately large initial deflections at elevated temperatures using finite element method

    NASA Technical Reports Server (NTRS)

    Gray, C. C.

    1990-01-01

    A finite-element formulation is developed for the free vibration of rectangular plates which are under the influence of moderately large stress-free initial deflections and large thermal deflections. The von Karman nonlinear strain-displacement relations are used to account for the thermal deflections. The plates are thin, isotropic, and Hookean in nature. The temperature imposed on the plate is assumed to be constant through the thickness of the plate. Uniform and sinusoidal temperature distributions are studied. The material properties of the plates are temperature-dependent due to the relatively high temperatures imposed on the plates.

  14. MEASUREMENT METHOD FOR WELDING RESIDUAL STRESS IN STEEL I-SHAPED GIRDER WITH THICK FLANGE AND ITS INFLUENCE ON LOAD CARRYING CAPACITY FOR BENDING

    NASA Astrophysics Data System (ADS)

    Miyashita, Takeshi; Inaba, Naofumi; Hirayama, Shigeyuki; Liu, Cuiping; Nagai, Masatsugu

    Recently, the construction number of steel girder bridge using thick plates has been increasing. It is afraid that residual stress in the thick plates affects the load carrying capacity of the girder. Therefore, this study aims to measure the distribution of residual stresses in the thick plates by mechanical cutting method. Herein, simplified measurement method is proposed for the measurement in the thickness direction. As a result, it was found that the slope of stress distribution in the thickness direction becomes large as the thickness of the plate increases. Then, after considering the equilibriums of residual stress three-dimensionally, the residual stress was introduced into a finite element analysis model, which is the modeling of an existing bridge at the intermediate support. It was confirmed that residual stress in the thick plate does not affect the load carrying capacity of steel girder in bending.

  15. Plates and FEM

    NASA Astrophysics Data System (ADS)

    Blaauwendraad, J.

    The word plate is a collective term for systems in which transfer of forces occurs in two directions; walls, deep beams, floors and bridge slabs are all plates. We distinguish two main categories, plates that are loaded in their plane, and plates loaded perpendicularly to their plane. For both categories we give an approach with differential equations, such that a basic understanding is provided and for certain characteristic cases an exact solution can be determined. We follow the displacement method, working with differential equations. In plates that are loaded in their plane, the plane stress state is called the membrane state. All stress components are parallel to the mid- plane of the plate. In special cases we can simply determine the stresses.

  16. Drag Measurements of Porous Plate Acoustic Liners

    NASA Technical Reports Server (NTRS)

    Wolter, John D.

    2005-01-01

    This paper presents the results of direct drag measurements on a variety of porous plate acoustic liners. The existing literature describes numerous studies of drag on porous walls with injection or suction, but relatively few of drag on porous plates with neither injection nor suction. Furthermore, the porosity of the porous plate in existing studies is much lower than typically used in acoustic liners. In the present work, the acoustic liners consisted of a perforated face sheet covering a bulk acoustic absorber material. Factors that were varied in the experiment were hole diameter, hole pattern, face sheet thickness, bulk material type, and size of the gap (if any) between the face sheet and the absorber material.

  17. Composite plates impact damage - An atlas

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; Springer, George S.

    1991-01-01

    The present volume on impact damage in composite plates presents an extensive compendium of visual and graphic data regarding a variety of material and impactor parameters. The photographs are taken with X-ray and C-scan imaging in conjunction with a dye penetrant to show matrix cracks and delaminations. Impact and static-loading tests are performed on plates of graphite-epoxy, graphite-toughened epoxy, and graphite-PEEK materials. The images are presented to yield specific visual data regarding such parameters as impactor velocity, thickness of the back ply group, impactor nose radius, and the effects of multiple delaminations. The images are grouped in eight subsets that correspond to parameters including plate length, material, and the difference in fiber orientation between adjacent ply groups. This substantial volume represents a systematic effort to study the effects of several material parameters on impact damage.

  18. Plating methods, a survey

    NASA Technical Reports Server (NTRS)

    Berkowitz, J. B.; Emerson, N. H.

    1972-01-01

    Results are presented of a comprehensive search of the literature available, much of which has been generated by the research centers of NASA and its contractors, on plating and coating methods and techniques. Methods covered included: (1) electroplating from aqueous solutions; (2) electroplating from nonaqueous solutions; (3) electroplating from fused-salt baths; (4) electroforming; (5) electroless plating, immersion plating, and mirroring; (6) electroplating from gaseous plasmas; and (7) anodized films and conversion coatings.

  19. Acceleration of metal plates

    SciTech Connect

    Marsh, S.P.; McQueen, R.G.; Tan, T.H.

    1989-01-01

    High-explosive charges have been used to accelerate stainless steel plates to velocities of 6-7 km/s. A two-stage system has been used in which the first stage is a plane-wave detonating system that accelerates the plate down a short barrel. The second stage consists of a hollow cylindrical charge through which the moving plate passes. After an adjustable delay this charge is detonated on the outer circumference of the entry side of the charge. Flash radiographs and witness plates show no breakup in the first stage but bowing and frequent breakup in the second stage. 6 figs.

  20. 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...

  1. 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

  2. Thickness measurement in composite materials using lamb waves viscoelastic effects.

    PubMed

    Moreno, E; Acevedo, P; Castillo, M

    2000-01-01

    Pulse propagation in plates has been investigated with the identification of Lamb modes. The application of this technique to the measurement of thickness in composite and coarse materials was previously evaluated. As a sequel, results of the application of this technique taking into account the viscoelastic properties of PVC and ferrocement are presented. PMID:11243464

  3. 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

  4. Analysis on formulas of concrete plate under contact explosion

    NASA Astrophysics Data System (ADS)

    Wang, Zheng; Liang, Longhe; Lou, Jianfeng

    2015-09-01

    Based on many test data of concrete plates of several thicknesses, this paper presents some new simple engineering formulas for computing critical thickness of scabbing and perforation, the front explosion diameter and the rear scabbing diameter of reinforced concrete plates under contact explosion. For the damage problem of a 20 cm thick concrete target under contact explosion of 1.25 kg TNT charge, the paper gives the numerical simulation results of LS-DYNA software for comparison. The damage zone of concrete plate in numerical simulation is determined by analysis of tension pressure resulted from shock wave reflection on the free boundary. And the numerical simulation results are in basic agreement on the results of these engineering formulas.

  5. Blue Willow Story Plates

    ERIC Educational Resources Information Center

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  6. 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

  7. COMPPAP - COMPOSITE PLATE BUCKLING ANALYSIS PROGRAM (IBM PC 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.

  8. 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.

  9. 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.

  10. 40 CFR Table 1 to Subpart Wwwwww... - Table 1 to Subpart WWWWWW of Part 63. Applicability of General Provisions to Plating and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Applicability of General Provisions to Plating and Polishing Area Sources 1 Table 1 to...Applicability of General Provisions to Plating and Polishing Area Sources Protection of Environment...Pollutants: Area Source Standards for Plating and Polishing Operations Pt. 63,...

  11. 40 CFR Table 1 to Subpart Wwwwww... - Table 1 to Subpart WWWWWW of Part 63. Applicability of General Provisions to Plating and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Applicability of General Provisions to Plating and Polishing Area Sources 1 Table 1 to...Applicability of General Provisions to Plating and Polishing Area Sources Protection of Environment...Pollutants: Area Source Standards for Plating and Polishing Operations Pt. 63,...

  12. Journal of Sound and Vibration (1996) 196(1), 107127 ATTENUATION OF WAVES IN PLATES AND BARS

    E-print Network

    Norris, Andrew

    1996-01-01

    Journal of Sound and Vibration (1996) 196(1), 107­127 ATTENUATION OF WAVES IN PLATES AND BARS USING of energy in a 10 thick steel plate is achieved for frequencies from 2­10 kHz, using this approach 1996) A new method is proposed for attenuating structural wave reflections at the edges of plates

  13. Conductivity fuel cell collector plate and method of fabrication

    DOEpatents

    Braun, James C. (Juno Beach, FL)

    2002-01-01

    An improved method of manufacturing a PEM fuel cell collector plate is disclosed. During molding a highly conductive polymer composite is formed having a relatively high polymer concentration along its external surfaces. After molding the polymer rich layer is removed from the land areas by machining, grinding or similar process. This layer removal results in increased overall conductivity of the molded collector plate. The polymer rich surface remains in the collector plate channels, providing increased mechanical strength and other benefits to the channels. The improved method also permits greater mold cavity thickness providing a number of advantages during the molding process.

  14. Inverse characterization of plates using zero group velocity Lamb modes.

    PubMed

    Grünsteidl, Clemens; Murray, Todd W; Berer, Thomas; Veres, István A

    2016-02-01

    In the presented work, the characterization of plates using zero group velocity Lamb modes is discussed. First, analytical expressions are shown for the determination of the k-? location of the zero group velocity Lamb modes as a function of the Poisson's ratio. The analytical expressions are solved numerically and an inverse problem is formulated to determine the unknown wave velocities in plates of known thickness. The analysis is applied to determine the elastic properties of tungsten and aluminum plates based on the experimentally measured frequency spectra. PMID:26527393

  15. 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.

  16. A hierarchy of dynamic equations for micropolar plates

    NASA Astrophysics Data System (ADS)

    Abadikhah, Hossein; Folkow, Peter D.

    2015-11-01

    This work considers homogeneous isotropic micropolar plates adopting a power series expansion method in the thickness coordinate. Variationally consistent equations of motion and end boundary conditions are derived in a systematic fashion up to arbitrary order for extensional and flexural displacement cases. The plate equations are asymptotically correct to all studied orders. Numerical results are presented for various orders of the present method, other approximate theories as well as the exact three dimensional theory. The results illustrate that the present approach may render benchmark solutions provided higher order truncations are used, and act as engineering plate equations using low order truncation.

  17. Two-dimensional nonlinear models for heterogeneous plates

    NASA Astrophysics Data System (ADS)

    Pruchnicki, Erick

    2009-05-01

    We consider a formal asymptotic study of plates with periodically rapidly varying heterogeneities. The asymptotic analysis is performed when both the period of change of the material properties and the thickness of the plate are of the same orders of magnitude. We consider a plate made of Ciarlet-Geymonat type materials (P.G. Ciarlet and G. Geymonat (1982)). Depending on the order of magnitude of the applied loads, we obtain a nonlinear membrane model and a nonlinear membrane inextensional-bending model as announced in E. Pruchnicki (2006). Our approach is based on a sequence of recursive minimization problems. To cite this article: E. Pruchnicki, C. R. Mecanique 337 (2009).

  18. 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

  19. Shear buckling response of tailored, rectangular, composite plates

    NASA Technical Reports Server (NTRS)

    Biggers, Sherrill B.; Pageau, Stephane S.

    1993-01-01

    The concept of stiffness tailoring for improved shear buckling resistance of rectangular composite plates is investigated analytically. The tailoring involves only the redistribution of the given material with given orientations to create beneficial stiffening patterns across the planform of the plate. The resulting local nonuniformities in thickness and membrane and bending stiffness combine to change the buckling response of the plate. The weight and average membrane shear stiffness are essentially unaffected by the tailoring. Practical limitations on the degree to which the tailoring may be carried out are shown to govern most designs. Improvements in the shear buckling load on the order of 50 percent are shown possible with monolithic tailoring. Tailored sandwich concepts, in which a light-weight core material is added to keep both plate surfaces flat, can produce improvements well over 100 percent in specific buckling loads compared with uniform composite plates.

  20. Three-dimensional solutions for antisymmetrically laminated anisotropic plates

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Burton, W. Scott

    1990-01-01

    Analytic three-dimensional elasticity solutions are presented for the stress and free vibration problems of multilayered anisotropic plates. The plates are assumed to have rectangular geometry and antisymmetric lamination with respect to the middle plane. A mixed formulation is used with the fundamental unknowns consisting of the six stress components and the three displacement components of the plate. Each of the plate variables is decomposed into symmetric and antisymmetric components in the thickness direction, and is expressed in terms of a double Fourier series in the Cartesian surface coordinates. Extensive numerical results are presented showing the effects of variation in the lamination and geometric parameters of composite plates on the importance of the transverse stress and strain components.

  1. A refined nonlinear theory of plates with transverse shear deformation

    NASA Technical Reports Server (NTRS)

    Reddy, J. N.

    1984-01-01

    A higher-order shear deformation theory of plates accounting for the von Karman strains is presented. The theory contains the same dependent unknowns as in the Hencky-Mindlin type first-order shear deformation theory and accounts for parabolic distribution of the transverse shear strains through the thickness of the plate. Exact solutions of simply supported plates are obtained using the linear theory and the results are compared with the exact solutions of three-dimensional elasticity theory, the first order shear deformation theory, and the classical plate theory. The present theory predicts the deflections, stresses, and frequencies more accurately when compared to the first-order theory and the classical plate theory.

  2. Application of the variational-asymptotical method to composite plates

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.; Lee, Bok W.; Atilgan, Ali R.

    1992-01-01

    A method is developed for the 3D analysis of laminated plate deformation which is an extension of a variational-asymptotical method by Atilgan and Hodges (1991). Both methods are based on the treatment of plate deformation by splitting the 3D analysis into linear through-the-thickness analysis and 2D plate analysis. Whereas the first technique tackles transverse shear deformation in the second asymptotical approximation, the present method simplifies its treatment and restricts it to the first approximation. Both analytical techniques are applied to the linear cylindrical bending problem, and the strain and stress distributions are derived and compared with those of the exact solution. The present theory provides more accurate results than those of the classical laminated-plate theory for the transverse displacement of 2-, 3-, and 4-layer cross-ply laminated plates. The method can give reliable estimates of the in-plane strain and displacement distributions.

  3. 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.

  4. Assessment of buccal bone thickness of aesthetic maxillary region: a cone-beam computed tomography study

    PubMed Central

    Flores, Tania; Navarro, Pablo; Salamanca, Carlos; Beltrán, Víctor; Borie, Eduardo

    2015-01-01

    Purpose The aim of this study was to analyze the anatomical dimensions of the buccal bone walls of the aesthetic maxillary region for immediate implant placement, based upon cone-beam computed tomography (CBCT) scans in a sample of adult patients. Methods Two calibrated examiners analyzed a sample of 50 CBCT scans, performing morphometric analyses of both incisors and canines on the left and right sides. Subsequently, in the sagittal view, a line was traced through the major axis of the selected tooth. Then, a second line (E) was traced from the buccal to the palatal wall at the level of the observed bone ridges. The heights of the buccal and palatal bone ridges were determined at the major axis of the tooth. The buccal bone thickness was measured across five lines. The first was at the level of line E. The second was at the most apical point of the tooth, and the other three lines were equidistant between the apical and the cervical lines, and parallel to them. Statistical analysis was performed with a significance level of P?0.05 for the bone thickness means and standard deviations per tooth and patient for the five lines at varying depths. Results The means of the buccal wall thicknesses in the central incisors, lateral incisors and canines were 1.14±0.65 mm, 0.95±0.67 mm and 1.15±0.68 mm, respectively. Additionally, only on the left side were significant differences in some measurements of buccal bone thickness observed according to age and gender. However, age and gender did not show significant differences in heights between the palatal and buccal plates. In a few cases, the buccal wall had a greater height than the palatal wall. Conclusions Less than 10% of sites showed more than a 2-mm thickness of the buccal bone wall, with the exception of the central incisor region, wherein 14.4% of cases were ?2 mm. PMID:26550524

  5. Rigid Top Plate Electronics Feed-through

    E-print Network

    . Ultrasonic transducers permit wave propagation measurement near 1 MHz. Fluid lines permit controlSample SupportRod Vessel Head Rigid Top Plate Electronics Feed-through Aluminum Standard Ultrasonic Transducer Pore Fluid Line Linear Bearing Shaker Shaker Housing Figure 3. Schematic of the low frequency

  6. 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.

  7. High loading uranium plate

    SciTech Connect

    Wiencek, T.C.; Domagala, R.F.; Thresh, H.R.

    1990-10-16

    Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pari of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat hiving a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process.

  8. SUEX process optimization for ultra-thick high-aspect ratio LIGA imaging

    NASA Astrophysics Data System (ADS)

    Johnson, Donald W.; Goettert, Jost; Singh, Varshni; Yemane, Dawit

    2011-04-01

    The focus of this paper is on the use of SUEX Thick Dry Film Sheet (TDFS) laminates which DJ DevCorp is developing as a thick resist material in optical and X-ray lithography. Preliminary thick dry film sheets up to 1mm thickness were successfully prepared and patterned at the CAMD X-ray beamlines and presented at HARMST 2007. Recently, new results have been published using SUEX resist sheets in UV lithography showing great market potential including plating molds for metal microparts, polymer MEMS, multilayer microfluidics structures, BioMEMS, medical devices, wafer level packaging processes, and displays. The SUEX TDFS are available in a range of thicknesses from 100?m to 1mm or more and are pre-cut into a number of standard wafer sizes. This new material is a modified epoxy formulation containing an antimony-free photo acid generator (PAG) prepared under a highly controlled solvent-less process which provides uniform coatings between two throw-away layers of protective polyester film. As part of our initial studies resist layers of 250, 500 and 1000?m were laminated onto regular silicon wafers using a hot roll laminator at a speed of 1ft/min at 75°C. The entire substrate preparation takes about 1 hour and with practice users can prepare up to 10 substrates in this time which are typically ready to use within 2 hours. In our efforts to develop a commercially viable product we have conducted experiments using standard equipment available at CAMD (Quintel UV aligner and CAMD XRLM 1 and 4 beamline). Initial X-ray exposure tests were done with a bottom dose ranging between 100 and 400 J/cm3 and a top/bottom dose ratio of less than 3 for sheets up to 2mm in thickness. Exposure time for typical conditions of the CAMD storage ring (ring current ranging between 100 and 160mA, beam lifetime of about 10hrs at 100mA ring current) is about 10-15min for a 4' wafer. After exposure the samples were immediately post exposure baked between 70°C and 110°C using a convection oven, taken out and cooled to RT then relaxed up to 3 days before development to reduce stress. Development was done in PGMEA for up to 3 hours for the 1000?m thick samples followed by a short IPA rinse and drying in air. Very high aspect ratios of 100 or more have been routinely patterned with nearly perfectly straight sidewalls (~1-1.5?m deviation for a 1mm tall structure) and excellent image fidelity.

  9. Curved-Channel Microchannel Plates

    NASA Astrophysics Data System (ADS)

    Laprade, Bruce; Cortez, Jose

    1984-01-01

    The curved-channel microchannel plate (C2 MCPTM) is the latest development in high gain microchannel technology. This new electron multiplier demonstrates many significant improvements over standard microchannel plates. Standard MCPs suffer from limited gain and ion feedback. The ion feedback is produced when residual gas molecules within the channels are ionized by secondary electrons. These positively charged ions now travel back through the channel, acquiring sufficient momentum to produce secondary electrons when the ion strikes the channel wall. These secondary electrons are in turn multiplied and result in spurious output pulses. In other instances the ion may leave the channel entirely and, in the case of image tubes, impinge upon the photocathode causing ion poisoning which eventually degrades the quantum efficiency of the cathode. In order to operate a microchannel plate in the high gain analog mode or photon counting mode, it becomes necessary to limit ion feedback. In the C2 MCP this is accomplished by curving the channels to a sufficient radius to reduce the distance an ion can travel prior to striking the channel wall, thus restricting its momentum and probability of producing secondaries which cause spurious pulses, which in turn degrade the noise figure. By substantially reducing the rate of ion feedback, it now becomes possible to operate a single MCP at gains in excess of 106, and since the C' MCP is a single piece electron multiplier, the spatial resolution of the electron image is maintained. The C2 MCP offers low noise uniform gain with either analog or pulse saturation outputs. The C2 MCP can be custom fabricated per customer dimensions.

  10. Thick brane solutions

    NASA Astrophysics Data System (ADS)

    Dzhunushaliev, Vladimir; Folomeev, Vladimir; Minamitsuji, Masato

    2010-06-01

    This paper gives a comprehensive review on thick brane solutions and related topics. Such models have attracted much attention from many aspects since the birth of the brane world scenario. In many works, it has been usually assumed that a brane is an infinitely thin object; however, in more general situations, one can no longer assume this. It is also widely considered that more fundamental theories such as string theory would have a minimal length scale. Many multidimensional field theories coupled to gravitation have exact solutions of gravitating topological defects, which can represent our brane world. The inclusion of brane thickness can realize a variety of possible brane world models. Given our understanding, the known solutions can be classified into topologically non-trivial solutions and trivial ones. The former class contains solutions of a single scalar (domain walls), multi-scalar, gauge-Higgs (vortices), Weyl gravity and so on. As an example of the latter class, we consider solutions of two interacting scalar fields. Approaches to obtain cosmological equations in the thick brane world are reviewed. Solutions with spatially extended branes (S-branes) and those with an extra time-like direction are also discussed.

  11. Forced vibrations of SC-cut quartz crystal rectangular plates with partial electrodes by the Lee plate equations.

    PubMed

    Wu, Rongxing; Wang, Wenjun; Chen, Guijia; Du, Jianke; Ma, Tingfeng; Wang, Ji

    2016-02-01

    Lee plate equations for high frequency vibrations of piezoelectric plates have been established and perfected over decades with the sole objective of obtaining accurate predictions of frequency and mode shapes to aid the analysis and design of quartz crystal resonators. The latest improvement includes extra terms related to derivatives of the flexural displacement to provide much accurate solutions for vibrations of the thickness-shear mode, which is the functioning mode of resonators and has much higher frequency than the flexural mode. The improved Lee plate equations have been used in the analysis of high frequency vibrations of quartz crystal plates as an essential step for analysis of AT- and SC-cut quartz crystal resonators after validations with fully electrode quartz crystal piezoelectric plates. In this study, closed-form solutions of free and forced vibrations of SC-cut quartz plates with partial electrodes are obtained. A procedure has been established for the calculation of dispersion relations, frequency spectra, selected vibration modes, and capacitance ratios of forced vibrations. The vibration solutions obtained with the first-order Lee plate equations are proven to be close to solutions from the Mindlin plate equations. It is now clear that both the Mindlin and Lee plate equations can be used in the analysis and design of quartz crystal resonators. PMID:26433435

  12. 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)

  13. Reduction of astrometric plates

    NASA Technical Reports Server (NTRS)

    Stock, J.

    1984-01-01

    A rapid and accurate method for the reduction of comet or asteroid plates is described. Projection equations, scale length correction, rotation of coordinates, linearization, the search for additional reference stars, and the final solution are examined.

  14. Experimental investigation on the dynamic response of clamped corrugated sandwich plates subjected to underwater impulsive loadings

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Zhang, Wei; Li, Dacheng; Hypervelocity Impact Research Center Team

    2015-06-01

    Corrugated sandwich plates are widely used in marine industry because such plates have high strength-to-weight ratios and blast resistance. The laboratory-scaled fluid-structure interaction experiments are performed to demonstrate the shock resistance of solid monolithic plates and corrugated sandwich plates by quantifying the permanent transverse deflection at mid-span of the plates as a function of impulsive loadings per areal mass. Sandwich structures with 6mm-thick and 10mm-thick 3003 aluminum corrugated core and 5A06 face sheets are compared with the 5A06 solid monolithic plates in this paper. The dynamic deformation of plates are captured with the the 3D digital speckle correlation method (DIC). The results affirm that sandwich structures show a 30% reduction in the maximum plate deflection compare with a monolithic plate of identical mass per unit area, and the peak value of deflection effectively reduced by increasing the thickness core. The failure modes of sandwich plates consists of core crushing, imprinting, stretch tearing of face sheets, bending and permanent deformation of entire structure with the increasing impulsive loads, and the failure mechanisms are analyzed with the postmortem panels and dynamic deflection history captured by cameras. National Natural Science Foundation of China (NO.: 11372088).

  15. Free vibrations of thermally stressed orthotropic plates with various boundary conditions

    NASA Technical Reports Server (NTRS)

    Bailey, C. D.; Greetham, J. C.

    1973-01-01

    An analytical investigation of the vibrations of thermally stressed orthotropic plates in the prebuckled region is presented. The investigation covers the broad class of trapezoidal plates with two opposite sides parallel. Each edge of the plate may be subjected to different uniform boundary conditions. variable thickness and arbitrary temperature distributions (analytical or experimental) for any desired combination of boundary conditions may be prescribed. Results obtained using this analysis are compared to experimental results obtained for isotropic plates with thermal stress, and to results contained in the literature for orthotropic plates without thermal stress. Good agreement exists for both sets of comparisons.

  16. Thermal effect on the linear and nonlinear analysis of cross-ply laminated plates

    SciTech Connect

    Lee, S.Y.; Ou, J.J.

    1993-12-31

    The cylindrical bending of cross ply laminated plates subjected to an uniform transverse load is evaluated via classical plate theory and Von Karman`s larger deflection plate theory, respectively. It is shown the influence of the temperature variation, boundary conditions, span to thickness ratio and stacking sequence on the accuracy of the linear analysis is quite significant. ne linear laminated plate theory may not be adequate for the analysis of several cross ply laminated plates even in small deflection range and at room temperature.

  17. Natural vibrations of laminated anisotropic plates using three-dimensional elasticity theory

    NASA Technical Reports Server (NTRS)

    Reddy, J. N.; Kuppusamy, T.

    1983-01-01

    The paper contains a description of the three-dimensional elasticity equations and the associated finite element model for natural vibrations of laminated anisotropic rectangular plates. The numerical results for natural frequencies are compared with those obtained by a shear deformable plate theory. A number of cross-ply and angle-ply rectangular plates are analyzed for natural frequencies. For relatively thick plates, the shear deformable-plate theory element predicts frequencies higher than those predicted by the three-dimensional elasticity theory element.

  18. Assessing Why Plates Move

    NASA Astrophysics Data System (ADS)

    Bowin, C.

    2004-05-01

    Over the past 42 years, since the first realization that the ocean floors are youthful (not ancient relics from early in the history of the Earth), and the concomitant development of the Theory of Plate Tectonics, an understanding of the observed motions has been sought. Speculation and analyses have concentrated upon three principal forces: ridge push, subducted slab pull, and sub-lithosphere traction from Earth's internal convection motions, with forces due to subducted slabs dominating. Some researchers have speculated that the motions of plates are random, however, the author in 1974 noting that a pattern of spreading between Australia and Antarctica progressed in time westward across the Indian Ocean, and then continued opening the Gulf of Aden and on into the Red Sea concluded that plate motions were not random. Recent evidence from the broad exposure of upper mantle rocks (peridotite) on the ocean floor at the ultra slow spreading Gakkel Ridge in the Arctic Ocean, indicate to the author that there is no ridge push force. Thus, seafloor-spreading sites are reactive features, not driving force contributors. A reconstruction of past absolute plate motions shows that sites of subduction have remained near their same arc/trench locations, but spreading centers and transform faults have moved about. Hence, confirming that sites of subduction are an important control for plate motions. The author's analysis of the positive residual geoid anomalies (spherical harmonic degrees 4-10) over arc/trench systems of the world, suggested forces of 2.8x1020-3.2x1021 N are available to drive plate tectonics. Some studies have proposed models for how such forces might couple to plate motions, but none have yet been definitive. New clues are being sought from the unique change in absolute plate motion of the Pacific plate, at about 46-48 Ma ago: from a northward subduction beneath the Aleutian trench/arc during the time when the Emperor seamount chain was formed, to its' present north of west motion subducting beneath the western Pacific trench/arcs, the direction during which the Hawaiian volcanic trend has been formed. Only the Pacific plate shows such a major change in absolute plate motion at that time, and the author takes this change, in but a few million years, to indicate that masses linked to slab subduction are more important than traction from an underlying mantle convection.

  19. Positive battery plate

    NASA Technical Reports Server (NTRS)

    Rowlette, John R. (Inventor)

    1985-01-01

    The power characteristics of a lead acid battery are improved by incorporating a dispersion of 1 to 10% by weight of a thermodynamically stable conductivity additive, such as conductive tin oxide coated glass fibers (34) of filamentary glass wool (42) in the positive active layer (32) carried on the grid (30) of the positive plate (16). Positive plate potential must be kept high enough to prevent reduction of the tin oxide to tin by utilizing an oversized, precharged positive paste.

  20. 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.

  1. 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.

  2. Experimental Structural Dynamic Response of Plate Specimens Due to Sonic Loads in a Progressive Wave Tube

    NASA Technical Reports Server (NTRS)

    Betts, Juan F.

    2001-01-01

    The objective of the current study was to assess the repeatability of experiments at NASA Langley's Thermal Acoustic Fatigue Apparatus (TAFA) facility and to use these experiments to validate numerical models. Experiments show that power spectral density (PSD) curves were repeatable except at the resonant frequencies, which tended to vary between 5 Hz to 15 Hz. Results show that the thinner specimen had more variability in the resonant frequency location than the thicker sample, especially for modes higher than the first mode in the frequency range. Root Mean Square (RMS) tended to be more repeatable. The RMS behaved linearly through the SPL range of 135 to 153 dB. Standard Deviations (STDs) of the results tended to be relatively low constant up to about 147 dB. The RMS results were more repeatable than the PDS results. The STD results were less than 10% of the RMS results for both the 0.125 in (0.318 cm) and 0.062 in (0.1588 cm) thick plate. The STD of the PSD results were around 20% to 100% of the mean PSD results for non-resonant and resonant frequencies, respectively, for the 0.125 in (0.318 cm) thicker plate and between 25% to 125% of the mean PSD results, for nonresonant and resonant frequencies, respectively, for the thinner plate.

  3. Three-beam interferogram analysis method for surface flatness testing of glass plates and wedges

    NASA Astrophysics Data System (ADS)

    Sunderland, Zofia; Patorski, Krzysztof

    2015-09-01

    When testing transparent plates with high quality flat surfaces and a small angle between them the three-beam interference phenomenon is observed. Since the reference beam and the object beams reflected from both the front and back surface of a sample are detected, the recorded intensity distribution may be regarded as a sum of three fringe patterns. Images of that type cannot be succesfully analyzed with standard interferogram analysis methods. They contain, however, useful information on the tested plate surface flatness and its optical thickness variations. Several methods were elaborated to decode the plate parameters. Our technique represents a competitive solution which allows for retrieval of phase components of the three-beam interferogram. It requires recording two images: a three-beam interferogram and the two-beam one with the reference beam blocked. Mutually subtracting these images leads to the intensity distribution which, under some assumptions, provides access to the two component fringe sets which encode surfaces flatness. At various stages of processing we take advantage of nonlinear operations as well as single-frame interferogram analysis methods. Two-dimensional continuous wavelet transform (2D CWT) is used to separate a particular fringe family from the overall interferogram intensity distribution as well as to estimate the phase distribution from a pattern. We distinguish two processing paths depending on the relative density of fringe sets which is connected with geometry of a sample and optical setup. The proposed method is tested on simulated data.

  4. Plate Rolling Modeling at Mill 5000 of OJSC ``Magnitogorsk Iron and Steel'' for Analysis and Optimization of Temperature Rates

    NASA Astrophysics Data System (ADS)

    Salganik, V.; Shmakov, A.; Pesin, A.; Pustovoytov, D.

    2010-06-01

    Modeling of strip deflected mode and thermal state in rolling is an integral part of the technology and perspective rolling-mill machinery such as plate mill 5000 of the OJSC "Magnitogorsk Iron and Steel". To comprehend metal behavior in the deformation zone in the rough passes during plate rolling it is essential to assess the impact of various temperature factors on variations in field of stress and strain intensities as well as temperature fields in deformation. To do such researches in consideration of various software products and adequate results one of the most effective methods nowadays is regarded as the method of finite elements. The research shows modeling of roughing rolling of a pipe steel sheet with strength category X80 according to standard API-5L. In the research of the metal deflected mode software product DEFORM 2D has been used for the isothermal and nonisothermic process. The mathematical modeling allows revealing the impact of temperature field on the metal deflected mode in the rough passes in plate rolling. Supposedly, it is deformation heating that can have more impact on the ingot temperature profile in the finishing passes in controlled rolling of the pipe steel grades. It is defined by high percent reduction, rolling speeds; more area of heat exchange surface; less thickness and lower temperature of rolling. The results can be used to develop efficient modes of plate rolling of the pipe steels.

  5. Titan's thick haze layer

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Titan's thick haze layer is shown in this enhanced Voyager 1 image taken Nov. 12, 1980 at a distance of 435,000 kilometers (270,000 miles). Voyager images of Saturn's largest moon show Titan completely enveloped by haze that merges with a darker 'hood' or cloud layer over the north pole. Such a mantle is not present at the south pole. At Voyager's closest approach to Titan on Nov. 11, 1980, spacecraft instruments found that the moon has a substantial atmosphere, far denser than that of Mars and possibly denser than Earth's. The Voyager Project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.

  6. Vibrational analysis of rectangular sandwich plates resting on some elastic point supports

    SciTech Connect

    Ichinomiya, Osamu; Maruyama, Koichi; Sekine, Kouji

    1995-11-01

    An approximate solution of forced-vibration for rectangular sandwich plate resting on some elastic point supports is presented. The sandwich plate has thin, anisotropic composite laminated faces and a thick orthotropic core. The simplified sandwich plate model is used in the analysis. The governing equation of elastically point supported rectangular sandwich plate is obtained by using the Lagrange equation. The steady state response solution to a sinusoidally varying point force is also derived. The response curves of rectangular sandwich plates having CFRP laminated faces and aluminum honeycomb core is calculated. Application examples illustrate the effects of laminate lay-up of face sheets, core material properties and core thickness ratio on the vibration characteristics of rectangular sandwich plate.

  7. Using ultrasonic SH waves to estimate the quality of adhesive bonds in plate structures

    NASA Astrophysics Data System (ADS)

    Yew, C. H.; Weng, X. W.

    1985-05-01

    A method using SH waves to estimate the quality of an adhesive layer in a bonded plate is presented in this paper. A mathematical analysis of SH-wave motions in a bonded plate consistent with the experimental arrangement was carried out in full. It is found that the cutoff frequency of the second mode waves in the plate is dependent upon the thickness and the mechanical properties of the adhesive layer, and the waves in the plate resonate at this frequency. This wave resonating phenomenon was used in the experimental determination of the property of the adhesive layer. An experimental verification of the method was carried out using adhesives of several different properties. It is demonstrated that the resonant frequency of the second mode wave in the plate is dependent upon the moduli and thickness ratio between the adhesive layer and plate as predicted by the analysis.

  8. 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.

  9. Caribbean plate interactions

    SciTech Connect

    Ball, M. )

    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.

  10. BEPLATE emdash simulation of electrochemical plating

    SciTech Connect

    Giles, G.E. ); Gray, L.J. ); Bullock, J.S. IV )

    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).

  11. Dual passband dichroic plate for X-band

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    A need arose in the Deep Space Network for a dichroic plate that would simultaneously pass two desired frequency bands in the X-band region. In addition, the plate must be totally reflective for S-band frequencies. A dielectrically loaded dichroic plate is described that was developed to meet this need. The unique microwave properties that the new dichroic plate had to possess were: (1) insertion losses of less than 0.04 dB for X-band uplink frequencies centered at 7167 MHz and for X-band downlink frequencies centered at about 8425 MHz; (2) insertion losses that met the low loss requirements at 30 deg incidence angle simultaneously for both parallel and perpendicular polarizations; (3) total reflectivity at S-band frequencies; and (4) ability to maintain these electrical characteristics while passing 100 kW of CW power at X-band or while reflecting 100 kW of CW power at S-band. The dual passband dichroic plate 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 the technical requirements.

  12. Dynamic characterization of a laminated composite magnetorheological fluid sandwich plate

    NASA Astrophysics Data System (ADS)

    Manoharan, R.; Vasudevan, R.; Jeevanantham, A. K.

    2014-02-01

    This study investigates the dynamic properties of a laminated composite magnetorheological (MR) fluid sandwich plate. The governing differential equations of motion of a sandwich plate embedding a MR fluid layer as the core layer and laminated composite plates as the face layers are presented in a finite element formulation. The validity of the developed finite element formulation is demonstrated by comparing the results in terms of the natural frequencies derived from the present finite element formulation with those in the available literature. Various parametric studies are also performed to investigate the effect of a magnetic field on the variation of the natural frequencies and loss factors of the MR fluid composite sandwich plate under various boundary conditions. Furthermore, the effect of the thickness of the MR fluid layer and the ply orientation of the composite face layers on the variation of the natural frequencies and loss factors are studied. The free vibration mode shapes under various boundary conditions of a MR fluid laminated composite sandwich plate are also presented. The forced vibration response of a MR fluid composite plate is investigated to study the dynamic response of the sandwich plate under harmonic force excitations in various magnetic fields. The study suggests that the natural frequency increases with increasing magnetic field, irrespective of the boundary conditions. The reduction in peak deflection at each mode under a harmonic excitation force with variation of the applied magnetic field shows the effectiveness of the MR fluid layer in reducing the vibration amplitude of the composite sandwich plate.

  13. 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.

  14. 46 CFR 57.06-2 - Production test plate interval of testing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... joint. (2) When the extent of welding on vessels welded in succession exceeds 50 lineal feet of either... each 50 feet of aggregate joint of the same material where the plate thicknesses fall within a range of one-fourth inch. For each 50-foot increment of weld, test plates shall be prepared at the time...

  15. The response of clamped sandwich plates with metallic foam cores to simulated blast loading

    E-print Network

    Fleck, Norman A.

    The response of clamped sandwich plates with metallic foam cores to simulated blast loading D increases with increasing thickness of sandwich core. Finite element simulations of these experiments and sandwich plates. Finally, the finite element simulations were employed to determine the pressure versus

  16. Ultrasonic measurement of residual stress relaxation in welded steel plates using critically refracted longitudinal waves 

    E-print Network

    Chance, Brent Houston

    2000-01-01

    specimen was approximately 30.5 cm by 40.6 cm and 1.3 cm thick (12 in by 16 in by 1/2 in). Each specimen was cut with T shaped slots cut from each edge of the plate. The geometry of the plate and the welds should provide for a uniaxial tension stress...

  17. Trapped Torsional Vibrations in Elastic Plates Min K. Kang and Rui Huang

    E-print Network

    Huang, Rui

    Trapped Torsional Vibrations in Elastic Plates Min K. Kang and Rui Huang Department of Aerospace observed that torsional vibrations can be trapped in elastic plates with circular regions of slightly sensing [1-3]. Energy trapping in QCM is usually achieved by confining thickness-shear mode vibrations

  18. Trapped torsional vibrations in elastic plates Texzec, Inc., Round Rock, Texas 78681

    E-print Network

    Huang, Rui

    Trapped torsional vibrations in elastic plates T. Knowles Texzec, Inc., Round Rock, Texas 78681 M November 2005 We report observation and analysis of trapped torsional vibrations in elastic plates. Each found extensive applications from vis- cometers to biodetectors. Thickness-shear mode vibrations

  19. Mouth Dryness or Thick Saliva

    MedlinePLUS

    ... throat pain or sores Mouth dryness or thick saliva Radiation therapy to the head and neck areas, ... other medicines can cause dry mouth or thick saliva. The glands that make saliva can become irritated ...

  20. Ultrasonic Inspection Of Thick Sections

    NASA Technical Reports Server (NTRS)

    Friant, C. L.; Djordjevic, B. B.; O'Keefe, C. V.; Ferrell, W.; Klutz, T.

    1993-01-01

    Ultrasonics used to inspect large, relatively thick vessels for hidden defects. Report based on experiments in through-the-thickness transmission of ultrasonic waves in both steel and filament-wound composite cases of solid-fuel rocket motors.

  1. 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 ...

  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. Liquid film thickness measurement by two-line TDLAS

    SciTech Connect

    Yang, Huinan; Chen, Jun; Cai, Xiaoshu; Greszik, Daniel; Dreier, Thomas; Schulz, Christof

    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.

  4. Ultrasonic thickness measurements on corroded steel members: a statistical analysis of error 

    E-print Network

    Konen, Keith Forman

    1999-01-01

    . Thickness measurements have been taken on corroded tubular members under a variety of surface conditions with both an ultrasonic thickness device and a micrometer. The error of the measurements has been determined by taking the standard deviation of a series...

  5. 49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation...PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Pipe Design § 192.109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall...

  6. 49 CFR 192.109 - Nominal wall thickness (t) for steel pipe.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Nominal wall thickness (t) for steel pipe. 192.109 Section 192.109 Transportation...PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Pipe Design § 192.109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall...

  7. 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.

  8. 40 CFR 426.44 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or...) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate...

  9. 40 CFR 426.44 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of...) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass...

  10. 40 CFR 426.44 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or...) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate...

  11. 40 CFR 426.44 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... comply with 40 CFR part 403. In addition, the following pretreatment standard establishes the quantity or...) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate...

  12. 40 CFR 426.44 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CFR part 403. In addition, the following pretreatment standard establishes the quantity or quality of...) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass...

  13. 40 CFR 426.44 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.44 Pretreatment standards for existing...

  14. 40 CFR 426.44 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.44 Pretreatment standards for existing...

  15. 40 CFR 426.46 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.46 Pretreatment standards for new sources. Any...

  16. 40 CFR 426.46 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.46 Pretreatment standards for new sources. Any...

  17. 40 CFR 426.46 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.46 Pretreatment standards for new sources. Any...

  18. 40 CFR 426.46 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.46 Pretreatment standards for new sources. Any...

  19. 40 CFR 426.44 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.44 Pretreatment standards for existing...

  20. 40 CFR 426.44 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.44 Pretreatment standards for existing...

  1. 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.

  2. 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.

  3. Oceanic Plate Bending Along the Manila Trench

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Lin, J.; Zhan, W.

    2014-12-01

    We quantify along-trench variations in plate flexural bending along the Manila trench in the South China Sea. A 3-D interpreted flexural deformation surface of the subducting South China Sea Plate was obtained by removing from the observed bathymetry the effects of sediment loading, isostatically-compensated topography based on gravity modeling, age-related lithospheric thermal subsidence, and residual short-wavelength features. We analyzed flexural bending of 21 across-trench profile sections along the Manila trench and then calculated five best-fitting tectonic and plate parameters that control the flexural bending for each of the across-trench profile sections. Results of analysis revealed significant along-trench variations: The trench relief of the Manila trench varies from 0.8 to 2.2 km, trench-axis vertical loading (-V0) from -0.4x1012 to 1.21x1012 N/m, and axial bending moment (-M0) from 0.005x1017 to 0.6x1017 N. The effective elastic plate thickness seaward of the Manila outer-rise region (TeM) ranges from 30 to 40 km, while that trench-ward of the outer-rise (Tem) ranges from 11 to 30 km. This corresponds to a reduction in Te of 26-63% for the Manila trench. The transition from TeM to Tem occurs at a breaking distance of 50-120 km from the Manila trench axis. The axial vertical loading, bending moment, and the effective elastic thickness of the Manila trench are much smaller than the Mariana trench (Zhang et al., 2014). The contrast in the flexural bending between the Mariana and Manila trenches might be related to the difference in the ages of the subducting plates and other tectonic variables. Zhang, F., Lin, J., Zhan, W., 2014. Variations in oceanic plate bending along the Mariana trench, Earth Planet. Sci. Lett. 401, 206-214. doi: 10.1016/j.epsl.2014.05.032

  4. Nuclear reactor alignment plate configuration

    DOEpatents

    Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R

    2014-01-28

    An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass.

  5. 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.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  7. 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.

  8. Proposed method for determining the thickness of glass in solar collector panels

    SciTech Connect

    Moore, D.M.

    1980-03-01

    An analytical method has been developed for determining the minimum thickness for simply supported, rectangular glass plates subjected to uniform normal pressure environmental loads such as wind, earthquake, snow, and deadweight. The method consists of comparing an analytical prediction of the stress in the glass panel to a glass breakage stress determined from fracture mechanics considerations. Based on extensive analysis using the nonlinear finite element structural analysis program ARGUS, design curves for the structural analysis of simply supported rectangular plates have been developed. These curves yield the center deflection, center stress and corner stress as a function of a dimensionless parameter describing the load intensity. Results are included for plates having length-to-width ratios of 1, 1.5, 2, 3, and 4. The load range considered extends to 1000 times the load at which the behavior of the plate becomes significantly nonlinear. Over the load range analyzed, the analysis shows that the ratio of center deflection to plate thickness for a plate of length-to-width ratio of 4 is less than 70 to 1, whereas linear theory would predict a center deflection about 1200 times the plate thickness. The stress is also markedly lower than would be predicted by linear theory. These analytical results show good agreement with the analytical and experimental work of others.

  9. Waterway Ice Thickness Measurements

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The ship on the opposite page is a U. S. Steel Corporation tanker cruising through the ice-covered waters of the Great Lakes in the dead of winter. The ship's crew is able to navigate safely by plotting courses through open water or thin ice, a technique made possible by a multi-agency technology demonstration program in which NASA is a leading participant. Traditionally, the Great Lakes-St. Lawrence Seaway System is closed to shipping for more than three months of winter season because of ice blockage, particularly fluctuations in the thickness and location of ice cover due to storms, wind, currents and variable temperatures. Shippers have long sought a system of navigation that would allow year-round operation on the Lakes and produce enormous economic and fuel conservation benefits. Interrupted operations require that industrial firms stockpile materials to carry them through the impassable months, which is costly. Alternatively, they must haul cargos by more expensive overland transportation. Studies estimate the economic benefits of year-round Great Lakes shipping in the hundreds of millions of dollars annually and fuel consumption savings in the tens of millions of gallons. Under Project Icewarn, NASA, the U.S. Coast Guard and the National Oceanic Atmospheric Administration collaborated in development and demonstration of a system that permits safe year-round operations. It employs airborne radars, satellite communications relay and facsimile transmission to provide shippers and ships' masters up-to-date ice charts. Lewis Research Center contributed an accurate methods of measuring ice thickness by means of a special "short-pulse" type of radar. In a three-year demonstration program, Coast Guard aircraft equipped with Side-Looking Airborne Radar (SLAR) flew over the Great Lakes three or four times a week. The SLAR, which can penetrate clouds, provided large area readings of the type and distribution of ice cover. The information was supplemented by short-pulse radar measurements of ice thickness. The radar data was relayed by a NOAA satellite to a ground station where NOAA analyzed it and created picture maps, such as the one shown at lower left, showing where icebreakers can cut paths easily or where shipping can move through thin ice without the aid of icebreakers. The ice charts were then relayed directly to the wheelhouses of ships operating on the Lakes. Following up the success of the Great Lakes program, the icewarn team applied its system in another demonstration, this one a similarly successful application designed to aid Arctic coast shipping along the Alaskan North Slope. Further improvement of the ice-monitoring system is planned. Although aircraft-mounted radar is effective, satellites could provide more frequent data. After the launch this year of Seasat, an ocean-monitoring satellite, NASA will conduct tests to determine the ice-mapping capability and accuracy of satellite radar images.

  10. 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.

  11. 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.

  12. ILLUSTRATIONS. PLATES-PART !.

    E-print Network

    .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 A M~THOD OF LOBSTER CULTURE: Plate VII. (r) General view of houseboat and floats. (2) Inside. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 VIII. (3) Floats from outer corner looking forward. (4) One of the outside floats, car raised. Specimen of rock from sponge beds off Anclote Key, Florida. . . . . . . . . . . . 403 XXIX. (I) Diving boat

  13. INL HIP Plate Fabrication

    SciTech Connect

    B. H. Park; C. R. Clark; J. F. Jue

    2010-02-01

    This document outlines the process used to bond monolithic fuel plates by Hot Isostatic Pressing (HIP). This method was developed at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. These foils have been used in a number of irradiation experiments in support of the United States Global Threat Reduction Initiative (GTRI) program.

  14. 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…

  15. Unitary plate electrode

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor); Clough, Thomas J. (Inventor); Josefowicz, Jack Y. (Inventor); Sibert, John W. (Inventor)

    1985-01-01

    The unitary electrode (10) comprises a porous sheet (12) of fiberglass the strands (14) of which contain a coating (16) of conductive tin oxide. The lower portion of the sheet contains a layer (18) of resin and the upper layer (20) contains lead dioxide forming a positive active electrode on an electrolyte-impervious layer. The strands (14) form a continuous conduction path through both layers (16, 18). Tin oxide is prevented from reduction by coating the surface of the plate facing the negative electrode with a conductive, impervious layer resistant to reduction such as a thin film (130) of lead or graphite filled resin adhered to the plate with a layer (31) of conductive adhesive. The plate (10) can be formed by casting a molten resin from kettle (60) onto a sheet of glass wool (56) overlying a sheet of lead foil and then applying positive active paste from hopper (64) into the upper layer (68). The plate can also be formed by passing an assembly of a sheet ( 80) of resin, a sheet (86) of sintered glass and a sheet (90) of lead between the nip (92) of heated rollers (93, 95) and then filling lead oxide into the pores (116) of the upper layer (118).

  16. 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.

  17. Benchmarks of simple, generic, shaped plates for validation of low-frequency electromagnetic computational codes

    NASA Technical Reports Server (NTRS)

    Deshpande, M. D.; Cockrell, C. R.; Beck, F. B.; Nguyen, T. X.

    1993-01-01

    The validation of low-frequency measurements and electromagnetic (EM) scattering computations for several simple, generic shapes, such as an equilateral-triangular plate, an equilateral-triangular plate with a concentric equilateral-triangular hole, and diamond- and hexagonal-shaped plates, is discussed. The plates were constructed from a thin aluminum sheet with a thickness of 0.08 cm. EM scattering by the planar plates was measured in the experimental test range (ETR) facility of NASA Langley Research Center. The dimensions of the plates were selected such that, over the frequency range of interest, the dimensions were in the range of lambda0 to 3(lambda0). In addition, the triangular plate with a triangular hole was selected to study internal-hole resonances.

  18. 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.

  19. A exact solution is presented for the cylindrical bending vibration of simply supported function-ally graded plates. Displacement functions that identically satisfy boundary conditions are used to

    E-print Network

    Vel, Senthil

    ABSTRACT A exact solution is presented for the cylindrical bending vibration of simply supported-to-thickness ratios. Keywords: Functionally graded material; thick plate; cylindrical bending; vibration. INTRODUCTION for the Cylindrical Bending Vibration of Functionally Graded Plates S. S. VEL AND R. C. BATRA Proceedings

  20. 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.

  1. 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.

  2. 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.

  3. Effect of bone cortical thickness on velocity measurements using ultrasonic axial transmission: a 2D simulation study.

    PubMed

    Bossy, Emmanuel; Talmant, Maryline; Laugier, Pascal

    2002-07-01

    In recent years, quantitative ultrasound (QUS) has played an increasing role in the assessment of bone status. The axial transmission technique allows to investigate skeletal sites such as the cortical layer of long bones (radius, tibia), inadequate to through-transmission techniques. Nevertheless, the type of propagation involved along bone specimens has not been clearly elucidated. Axial transmission is investigated here by means of two-dimensional simulations at 1 MHz. We focus our interest on the apparent speed of sound (SOS) of the first arriving signal (FAS). Its dependence on the thickness of the plate is discussed and compared to previous work. Different time criteria are used to derive the apparent SOS of the FAS as a function of source-receiver distance. Frequency-wave number analysis is performed in order to understand the type of propagation involved. For thick plates (thickness>lambdabone, longitudinal wavelength in bone), and for a limited range of source-receiver distances, the FAS corresponds to the lateral wave. Its velocity equals the longitudinal bulk velocity of the bone. For plate thickness less than lambdabone, some plate modes contribute to the FAS, and the apparent SOS decreases with the thickness in a way that depends on both the time criterion and on the source-receiver distance. The FAS corresponds neither to the lateral wave nor to a single plate mode. For very thin plates (thickness< lambdabone/4), the apparent SOS tends towards the velocity of the lowest order symmetrical vibration mode (S0 Lamb mode). PMID:12141355

  4. Higher Accurate Estimation of Axial and Bending Stiffnesses of Plates Clamped by Bolts

    NASA Astrophysics Data System (ADS)

    Naruse, Tomohiro; Shibutani, Yoji

    Equivalent stiffness of clamped plates should be prescribed not only to evaluate the strength of bolted joints by the scheme of “joint diagram” but also to make structural analyses for practical structures with many bolted joints. We estimated the axial stiffness and bending stiffness of clamped plates by using Finite Element (FE) analyses while taking the contact condition on bearing surfaces and between the plates into account. The FE models were constructed for bolted joints tightened with M8, 10, 12 and 16 bolts and plate thicknesses of 3.2, 4.5, 6.0 and 9.0 mm, and the axial and bending compliances were precisely evaluated. These compliances of clamped plates were compared with those from VDI 2230 (2003) code, in which the equivalent conical compressive stress field in the plate has been assumed. The code gives larger axial stiffness for 11% and larger bending stiffness for 22%, and it cannot apply to the clamped plates with different thickness. Thus the code shall give lower bolt stress (unsafe estimation). We modified the vertical angle tangent, tan?, of the equivalent conical by adding a term of the logarithm of thickness ratio t1/t2 and by fitting to the analysis results. The modified tan? can estimate the axial compliance with the error from -1.5% to 6.8% and the bending compliance with the error from -6.5% to 10%. Furthermore, the modified tan? can take the thickness difference into consideration.

  5. 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

  6. 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.

  7. DVR plating of distal radius fractures.

    PubMed

    Vanhaecke, J; Fernandez, D L

    2015-11-01

    Volar plating has become the standard of care for most distal radius fractures. When done for the right indication and with adequate mastering of the technique complication ratio is low. The concept of subchondral support is key in this technique. Osteoporotic patients will especially benefit from this type of fixation which allows early immobilization, quick return to activities of daily living and early good outcome. PMID:26319206

  8. History and Evolution of Precambrian plate tectonics

    NASA Astrophysics Data System (ADS)

    Fischer, Ria; Gerya, Taras

    2014-05-01

    Plate tectonics is a global self-organising process driven by negative buoyancy at thermal boundary layers. Phanerozoic plate tectonics with its typical subduction and orogeny is relatively well understood and can be traced back in the geological records of the continents. Interpretations of geological, petrological and geochemical observations from Proterozoic and Archean orogenic belts however (e.g., Brown, 2006), suggest a different tectonic regime in the Precambrian. Due to higher radioactive heat production the Precambrian lithosphere shows lower internal strength and is strongly weakened by percolating melts. The fundamental difference between Precambrian and Phanerozoic tectonics is therefore the upper-mantle temperature, which determines the strength of the upper mantle (Brun, 2002) and the further tectonic history. 3D petrological-thermomechanical numerical modelling experiments of oceanic subduction at an active plate at different upper-mantle temperatures show these different subduction regimes. For upper-mantle temperatures < 175 K above the present day value a subduction style appears which is close to present day subduction but with more frequent slab break-off. At upper-mantle temperatures 175 - 250 K above present day values steep subduction continues but the plates are weakened enough to allow buckling and also lithospheric delamination and drip-offs. For upper-mantle temperatures > 250 K above the present day value no subduction occurs any more. The whole lithosphere is delaminating and due to strong volcanism and formation of a thicker crust subduction is inhibited. This stage of 200-250 K higher upper mantle temperature which corresponds roughly to the early Archean (Abbott, 1994) is marked by strong volcanism due to sublithospheric decompression melting which leads to an equal thickness for both oceanic and continental plates. As a consequence subduction is inhibited, but a compressional setup instead will lead to orogeny between a continental or felsic terrain and an oceanic or mafic terrain as well as internal crustal convection. Small-scale convection with plume shaped cold downwellings also in the upper mantle is of increased importance compared to the large-scale subduction cycle observed for present temperature conditions. It is also observed that lithospheric downwellings may initiate subduction by pulling at and breaking the plate. References: Abbott, D., Drury, R., Smith, W.H.F., 1994. Flat to steep transition in subduction style. Geology 22, 937-940. Brown, M., 2006. Duality of thermal regimes is the distinctive characteristic of plate tectonics since the neoarchean. Geology 34, 961-964. Brun, J.P., 2002. Deformation of the continental lithosphere: Insights from brittle-ductile models. Geological Society, London, Special Publications 200, 355-370.

  9. Estimation of trabecular thickness using ultrasonic backcatter.

    PubMed

    Padilla, Frédéric; Jenson, Frédéric; Laugier, Pascal

    2006-01-01

    We present a method to estimate trabecular thickness (Tb.Th) in trabecular bones from ultrasound backscatter measurements. The estimation scheme is based on a nonlinear adjustment of predictions from a model to experimental data. The model assumes weak scattering from bone, where scattering is assumed to arise from the elastic solid trabeculae. The fluctuations of acoustical properties between bone tissue and the saturating fluid are assumed to be random and are described by the 3-D spatial autocorrelation function of the medium. In this paper, a Gaussian autocorrelation function is used. The inversion procedure is applied to a set of data measured on 33 femoral bone specimens. Results show that the model can predict both the magnitude and the frequency-dependence of the backscatter coefficient (root mean square error RMSE = 1 dB). The estimated trabecular thickness values are compared to the true trabecular thickness measured on high resolution microcomputed tomography 3-D reconstruction of bones microarchitecture. A close agreement is obtained on average over the group of specimens between predictions and the reference values: true Tb.Th is 132 +/- 12 microm and estimated Tb.Th is 134 +/- 15 microm. However, a moderate correlation between actual and estimated Tb.Th values is found (R2 = 0.44, p<10(-4), RMSE = 8.7 microm) suggesting a modest predictability at the individual level. Sources for the variability of the estimator are studied. Using synthetic rf signals, we demonstrate that the fundamental limitation of the estimator due to speckle noise is approximately 5 microm. Taking into account the measurement errors, the total uncertainty on Tb.Th estimates is of the order of 7 microm. The influence of the attenuation compensation function used to derive the backscatter coefficient is studied. In particular, we demonstrate the necessity of compensating for the effect of the gating time window. The results are discussed with respect to their meaningful clinical value. The requirements to be fulfilled by the performance of the technique change with regard to the question being posed. Two different strategies are examined: 1. characterize trabecular thickness without consideration of bone quantity (or bone mineral density) and 2. estimate trabecular thickness after adjustment for BMD. Considering the first strategy, a comparison between the precision of our estimator and the biological variability leads us to the conclusion that our estimator should only permit to distinguish between micro-architectures characterized by extreme values of trabecular thickness (i.e., very thin or very thick trabecular thickness). In this respect, it would be interesting to test whether the estimator is able to discriminate between rod-like (thin) and plate-like (thick) structures that are known to influence differently bone strength. The second strategy is more demanding in terms of technique performance and our estimator is not able yet to catch small differences in Tb.Th values expected after adjustment to bone density. Progress in the field will require a significant reduction in speckle noise and measurement errors and/or the development of other and more efficient microstructural estimators. PMID:16924879

  10. 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.

  11. 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.

  12. Impedance of infinite Kirchhoff and Mindlin plates with a rigid circular massless plug.

    PubMed

    Zapfe, Jeffrey A; Moore, James A

    2012-05-01

    Point force impedance expressions have been previously developed for infinite Kirchhoff and Mindlin plates. The present work develops impedance expressions for the more general case of an infinite plate with a circular, massless, rigid plug using both Kirchhoff and Mindlin plate theories. The models have been developed to analyze vibration propagation in buildings. The plate with the rigid plug provides a more reasonable model of the kinematic constraint at the column/floor interface. The models are used to investigate the potential benefits of using thick floors to block the transmission of structure-borne vibration in buildings. PMID:22559358

  13. 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.

  14. 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.

  15. North American plate dynamics

    NASA Technical Reports Server (NTRS)

    Richardson, Randall M.; Reding, Lynn M.

    1991-01-01

    Deformation within the North American plate in response to various tectonic processes is modeled using an elastic finite element analysis. The tectonic processes considered in the modeling include ridge forces associated with the normal thermal evolution of oceanic lithosphere, shear and normal stresses transmitted across transforms, normal stresses transmitted across convergent boundaries, stresses due to horizontal density contrasts within the continent, and shear tractions applied along the base of the plate. Model stresses are calculated with respect to a lithostatic reference stress state. Shear stresses transmitted across transform boundaries along the San Andreas and Caribbean are small, of the order of 5-10 MPa. Also, compressive stresses of the order of 5-10 MPa transmitted across the major transforms improve the fit to the data. Compressive stresses across convergent margins along the Aleutians and the Middle America trench are important.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Thick hollow cylindrical waveguides: A theoretical, numerical and experimental study

    NASA Astrophysics Data System (ADS)

    Ziaja, Aleksandra; Cheng, Li; Su, Zhongqing; Packo, Pawel; Pieczonka, Lukasz; Uhl, Tadeusz; Staszewski, Wieslaw

    2015-08-01

    The paper investigates elastic waves guided by thick-walled, hollow cylindrical structures. Theoretical, numerical and experimental investigations are presented to facilitate understanding of various wave propagation phenomena in thick-walled cylinders for potential damage detection applications. Semi-analytical analysis of dispersion characteristics is performed, revealing a repetitive pattern of coupled pairs of higher-order longitudinal modes. This behaviour is found to be analogue to terrace-like structures formed by interlacing high-frequency symmetric and antisymmetric plate mode curves. A hyperbolic behaviour of curves and modeshape transitions is observed due to mode coupling. The work presented demonstrates analytically how solutions for a thick-walled hollow cylinder correspond to the Lamb wave theory. The relevant pseudo-symmetry relations for mode displacement patterns are obtained using asymptotic approximations of Bessel functions. Theoretical solutions of dispersion characteristics are compared with numerical simulations that are based on the local interaction simulation approach. The results are validated experimentally using laser vibrometry.

  1. Capacitance probes for measurement of liquid film thickness

    SciTech Connect

    Chen, X.; Butler, T.; Brill, J.P.

    1996-12-31

    Liquid film thickness measurement is very important in multiphase science and technology. A capacitance probe is presented in this paper, including its basic principle, geometrical design, electronic circuit, and experimental tests in measuring film thickness during gas-liquid two-phase flow. This method is based on the difference between the dielectric constants of the gas and liquid phases. A ratio-arm bridge circuit is used to convert the capacitance of the fluids between twin parallel plates into voltage. The voltage output from the capacitance probe exhibits an excellent linear relationship with the liquid film thickness. Experiments have shown that the parallel-probe capacitance method is very suitable to gas-hydrocarbon liquid system.

  2. Plated wire memory subsystem

    NASA Technical Reports Server (NTRS)

    Reynolds, L.; Tweed, H.

    1972-01-01

    The work performed entailed the design, development, construction and testing of a 4000 word by 18 bit random access, NDRO plated wire memory for use in conjunction with a spacecraft imput/output unit and central processing unit. The primary design parameters, in order of importance, were high reliability, low power, volume and weight. A single memory unit, referred to as a qualification model, was delivered.

  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. Elastic plate spallation

    NASA Technical Reports Server (NTRS)

    Oline, L.; Medaglia, J.

    1972-01-01

    The dynamic finite element method was used to investigate elastic stress waves in a plate. Strain displacement and stress strain relations are discussed along with the stiffness and mass matrix. The results of studying point load, and distributed load over small, intermediate, and large radii are reported. The derivation of finite element matrices, and the derivation of lumped and consistent matrices for one dimensional problems with Laplace transfer solutions are included. The computer program JMMSPALL is also included.

  5. 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...

  6. 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.

  7. Measuring the wavenumber of guided modes in waveguides with linearly varying thickness.

    PubMed

    Moreau, Ludovic; Minonzio, Jean-Gabriel; Talmant, Maryline; Laugier, Pascal

    2014-05-01

    Measuring guided waves in cortical bone arouses a growing interest to assess skeletal status. In most studies, a model of waveguide is proposed to assist in the interpretation of the dispersion curves. In all the reported investigations, the bone is mimicked as a waveguide with a constant thickness, which only approximates the irregular geometry of cortical bone. In this study, guided mode propagation in cortical bone-mimicking wedged plates is investigated with the aim to document the influence on measured dispersion curves of a waveguide of varying thickness and to propose a method to overcome the measurement limitations induced by such thickness variations. The singular value decomposition-based signal processing method, previously introduced for the detection of guided modes in plates of constant thickness, is adapted to the case of waveguides of slowly linearly variable thickness. The modification consists in the compensation at each frequency of the wavenumber variations induced by the local variation in thickness. The modified method, tested on bone-mimicking wedged plates, allows an enhanced and more accurate detection of the wavenumbers. Moreover, the propagation in the directions of increasing and decreasing thickness along the waveguide is investigated. PMID:24815245

  8. 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).

  9. Hierarchic plate and shell models based on p-extension

    NASA Technical Reports Server (NTRS)

    Szabo, Barna A.; Sahrmann, Glenn J.

    1988-01-01

    Formulations of finite element models for beams, arches, plates and shells based on the principle of virtual work was studied. The focus is on computer implementation of hierarchic sequences of finite element models suitable for numerical solution of a large variety of practical problems which may concurrently contain thin and thick plates and shells, stiffeners, and regions where three dimensional representation is required. The approximate solutions corresponding to the hierarchic sequence of models converge to the exact solution of the fully three dimensional model. The stopping criterion is based on: (1) estimation of the relative error in energy norm; (2) equilibrium tests, and (3) observation of the convergence of quantities of interest.

  10. A simple higher-order theory for laminated composite plates

    NASA Technical Reports Server (NTRS)

    Reddy, J. N.

    1984-01-01

    A higher-order shear deformation theory of laminated composite plates is developed. The theory contains the same dependent unknowns as in the first-order shear deformation theory of Whitney and Pagano (1970), but accounts for parabolic distribution of the transverse shear strains through the thickness of the plate. Exact closed-form solutions of symmetric cross-ply laminates are obtained and the results are compared with three-dimensional elasticity solutions and first-order shear deformation theory solutions. The present theory predicts the deflections and stresses more accurately when compared to the first-order theory.

  11. Welded tie plate feasibility study for ITER central solenoid structure

    NASA Astrophysics Data System (ADS)

    Walsh, R.; McRae, D.; Dalder, E.; Litherland, S.; Goddard, R.; Han, K.; Trosen, M.; Kuhlmann, D. D.

    2014-01-01

    The result of a Nitronic 50 (N50) weld-screening program conducted in support of CS-Tie Plate Structure Design and Development is reported here. The goal of this program is to evaluate four different weld practices and to select the best weld practice for thick section welding of the N50 tie plate structure. The structure design specifies both the weld and base metals have the same minimum mechanical properties requirements. The criteria for selecting the best weld practice are based on the combination of the 295 K tensile properties and the 4 K-tensile, fatigue, and fracture-toughness properties.

  12. An exact analysis of a rectangular plate piezoelectric generator.

    PubMed

    Yang, Jiashi; Chen, Ziguang; Hu, Yuantai

    2007-01-01

    We study thickness-twist vibration of a finite, piezoelectric plate of polarized ceramics or 6-mm crystals driven by surface mechanical loads. An exact solution from the three-dimensional equations of piezoelectricity is obtained. The plate is properly electroded and connected to a circuit such that an electric output is generated. The structure analyzed represents a piezoelectric generator for converting mechanical energy to electrical energy. Analytical expressions for the output voltage, current, power, efficiency, and power density are given. The basic behaviors of the generator are shown by numerical results. PMID:17225813

  13. Damping of Intrinsic Temperature Oscillations in a 4 K Pulse Tube Cooler by Means of Rare Earth Plates

    NASA Astrophysics Data System (ADS)

    Allweins, K.; Qiu, L. M.; Thummes, G.

    2008-03-01

    Regenerative cryocoolers show oscillations of the refrigeration temperature that result from the periodic expansion of the working fluid (He). In case of cryogen-free operation of sensitive superconducting devices the temperature oscillations can be rather disturbing because of the associated variation of critical device parameters. The oscillations can be damped by increasing the thermal mass attached to the cold end. Here we report on the damping of temperature oscillations by making use of the high specific heat of rare-earth alloys, such as ErNi. Tests were performed on an in-house made 4 K pulse tube cooler. The damping is accomplished by ErNi plates of different thickness that were installed between the 4 K stage and the device mounting platform. With a 3.6 mm thick ErNi plate the temperature oscillation at 4 K was reduced by a factor of 19 from 275 mK to 14.5 mK, which is sufficiently low to operate an AC Josephson voltage standard.

  14. Symmetries in laminated composite plates

    NASA Technical Reports Server (NTRS)

    Noor, A. K.

    1976-01-01

    The different types of symmetry exhibited by laminated anisotropic fibrous composite plates are identified and contrasted with the symmetries of isotropic and homogeneous orthotropic plates. The effects of variations in the fiber orientation and the stacking sequence of the layers on the symmetries exhibited by composite plates are discussed. Both the linear and geometrically nonlinear responses of the plates are considered. A simple procedure is presented for exploiting the symmetries in the finite element analysis. Examples are given of square, skew and polygonal plates where use of symmetry concepts can significantly reduce the scope and cost of analysis.

  15. 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.

  16. PLATE WAVE RESONANCE WITH AIR-COUPLED ULTRASONICS

    SciTech Connect

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

    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. Crustal Structure of the Tengchong Intra-plate Volcanic Area

    NASA Astrophysics Data System (ADS)

    Qian, Rongyi; Tong, Vincent C. H.

    2015-09-01

    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.

  18. Nonlinear analysis of piezoelectric nanocomposite energy harvesting plates

    NASA Astrophysics Data System (ADS)

    Rafiee, M.; He, X. Q.; Liew, K. M.

    2014-06-01

    This paper investigates the nonlinear analysis of energy harvesting from piezoelectric functionally graded carbon nanotube reinforced composite plates under combined thermal and mechanical loadings. The excitation, which derives from harmonically varying mechanical in-plane loading, results in parametric excitation. The governing equations of the piezoelectric functionally graded carbon nanotube reinforced composite plates are derived based on classical plate theory and von Kármán geometric nonlinearity. The material properties of the nanocomposite plate are assumed to be graded in the thickness direction. The single-walled carbon nanotubes (SWCNTs) are assumed to be aligned, straight and have a uniform layout. The linear buckling and vibration behavior of the nanocomposite plates is obtained in the first step. Then, Galerkin’s method is employed to derive the nonlinear governing equations of the problem with cubic nonlinearities associated with mid-plane stretching. Periodic solutions are determined by using the Poincaré-Lindstedt perturbation scheme with movable simply supported boundary conditions. The effects of temperature change, the volume fraction and the distribution pattern of the SWCNTs on the parametric resonance, in particular the amplitude of vibration and the average harvested power of the smart functionally graded carbon nanotube reinforced composite plates, are investigated through a detailed parametric study.

  19. Flows past Long Plates under Cross-Stream Oscillatory Forcing

    NASA Astrophysics Data System (ADS)

    Tan, Boon T.; Thompson, Mark C.; Hourigan, Kerry

    1998-11-01

    The long rectangular plate exhibits shedding from both the leading and trailing edges. The interaction between the shear layers results in a feedback loop and has been clasified as the impinging leading edge vortex instability. This instability is weak and at low Reynolds numbers( Re plate length. At higher Reynolds numbers, it can be excited when a perturbation is applied. The incompressible Navier-Stokes equations were solved numerically using a high-order spectral element technique in space and a classical three step time-splitting temporal scheme. Three dimensional simulations use a Fourier expansion in the third dimension. The instability is receptive to small sinusoidal cross-flow perturbations (2.5% of free stream applied at the boundaries) and locks over a wide range of Strouhal numbers (St?0.12-0.2) at Re=400 based on plate thickness. A comparison of mean base pressure obtained numerically from two-dimensional simulations and observed experimentally show similar trends when forcing is applied. Three-dimensional simulations without forcing show the vortices on the surface of the plate form a staggered hair-pin pattern. These vortices, and streamwise vortecies that form in the trailing edge shear layers, strongly affect the drag experienced by the plate. Animations of several simulations can be obtained plate.html>here.

  20. 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).

  1. 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.

  2. Plated wire memory subsystem

    NASA Technical Reports Server (NTRS)

    Carpenter, K. H.

    1974-01-01

    The design, construction, and test history of a 4096 word by 18 bit random access NDRO Plated Wire Memory for use in conjunction with a spacecraft input/output and central processing unit is reported. A technical and functional description is given along with diagrams illustrating layout and systems operation. Test data is shown on the procedures and results of system level and memory stack testing, and hybrid circuit screening. A comparison of the most significant physical and performance characteristics of the memory unit versus the specified requirements is also included.

  3. Study on microwave emission mechanisms on the basis of hypervelocity impact experiments on various target plates

    NASA Astrophysics Data System (ADS)

    Ohnishi, H.; Chiba, S.; Soma, E.; Ishii, K.; Maki, K.; Takano, T.; Hasegawa, S.

    2007-06-01

    It was formerly confirmed by experiment that hypervelocity impacts on aluminum plates cause microwave emission. In this study, we have carried out experiments in order to clarify the mechanism of the emission. The microwave is detected by heterodyne detection scheme at 22 and 2 GHz with an intermediate frequency bandwidth of 500 and 120 MHz, respectively. A nylon projectile is accelerated using a light-gas gun to impact a target. First, aluminum plates with ten different thicknesses ranging from 1 to 40 mm were used as a target, and microwave signals were detected. The experimental results are statistically analyzed assuming a Gaussian distribution of the emitted power. The standard deviation of pulse voltage is calculated to show the existence of two kinds of signals: sharp pulse and thermal noise. It is shown that the emitted energy and the dispersion have a relation with the extent of the target destruction. Next, nylon projectiles are impacted on different metals such as aluminum, iron, and copper. These results suggest that microcracks are essential to microwave emission. Finally, in order to clarify the mechanism of charging and discharging across the microcracks, the experimental results are compared with this model for the following factors: (1) the thermally excited electrons and the emitted power, and (2) the bond dissociation energy of target material and emitted power. The analytical results suggest that electrons are excited thermally and by transition from a crystalline state to an atomic state.

  4. 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.

  5. High-temperature measurement using Cu-plating fiber Bragg grating for metal smart structure applications

    NASA Astrophysics Data System (ADS)

    Chang, Tianying; Jia, Lei; Sui, Qingmei; Cui, Hong-Liang

    2014-03-01

    High-temperature experiments for electroless Cu-plating Fiber Bragg Grating (FBG) indicate that Cu-plating FBG can measure high-temperature up to (even beyond) 300°C and it has high linearity, accuracy and repeatability. We can control Cu-plating FBG's temperature sensitivity by controlling plating layer's thickness. Temperature sensitivity of FBG with Cu-plating can be improved by more than three times with no less than 300?mthick coating by electroless and electrical Cu-plating. Such FBG can be soldered onto metal structures to get good bonding with the structure. As a result, such fiber sensors can get good protection, and high-temperature monitoring of smart structure is obtained.

  6. 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.

  7. Regional anomalies of sediment thickness, basement depth and isostatic crustal thickness in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Louden, Keith E.; Tucholke, Brian E.; Oakey, Gordon N.

    2004-07-01

    We calculate the anomalous basement topography for the North Atlantic Ocean from 30° to 70°N latitude and from 0° to 70°W longitude at a resolution of roughly 6×6 km, using grids of total sediment thickness and observed and predicted sea-floor bathymetry to correct for the effects of isostatic sediment loading and lithospheric age. Plotting this residual topography for various plate reconstructions during opening of the North Atlantic, we delineate consistent patterns of basement highs related to variations in hotspot-related volcanism. In addition to Iceland and the Azores, we recognize three centers of excess volcanism at the mid-Atlantic ridge: the Milne Seamounts and Azores-Biscay Rise (˜75-40 Ma), the Southeast Newfoundland Ridge and Madeira-Tore Rise (˜130-110 Ma), and the East and West Thulean Rises (˜60-50 Ma). The duration of volcanic activity ranges from 8 to 10 m.y. (Thulean Rises) to 60 m.y. (Iceland) and thus it appears that both long- and short-lived hotspots coexist, even in relatively close proximity. In contrast, during the period 110-60 Ma we observe little excess volcanism during either continental breakup or seafloor spreading. We estimate isostatic crustal thickness from the anomalous basement depths, after first removing dynamic effects created by mantle flow. Maximum thicknesses of volcanic features, from 30 km beneath the Greenland-Iceland-Faeroe ridge to ˜15 km beneath the Azores-Biscay Rise, are broadly consistent with seismic data and predictions of decompression melting. Widths of volcanic features indicate that thickening primarily occurs within 100-200 km of hotspots except along continental margins that rifted at the time of the hotspot activity (i.e. East Greenland and the Hatton-Rockall Bank). We observe conjugate structures south of Greenland and Edoras Bank, where excess volcanism appears to have extended beyond the margin proper and into oceanic crust. Similar conjugate features appear in the Labrador Sea south of Davis Strait. Finally, we identify anomalous oceanic regions adjacent to some continental margins, where unusually low values of predicted crustal thickness suggest either additional variations in plate properties or non-isostatic effects within the mantle.

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

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.; Sutyrin, Vladislav G.; Lee, Bok Woo

    1993-01-01

    The main purpose of this research was to develop a rigorous theory and corresponding computational algorithms for through-the-thickness analysis of composite plates. This type of analysis is needed in order to find the elastic stiffness constants for a plate and to post-process the resulting plate solution in order to find approximate three-dimensional displacement, strain, and stress distributions throughout the plate. This also requires the development of finite deformation plate equations which are compatible with the through-the-thickness analyses. After about one year's work, we settled on the variational-asymptotical method (VAM) as a suitable framework in which to solve these types of problems. VAM was applied to laminated plates with constant thickness in the work of Atilgan and Hodges. The corresponding geometrically nonlinear global deformation analysis of plates was developed by Hodges, Atilgan, and Danielson. A different application of VAM, along with numerical results, was obtained by Hodges, Lee, and Atilgan. An expanded version of this last paper was submitted for publication in the AIAA Journal.

  9. Investigation and performance tests of a new parallel plate ionization chamber with double sensitive volume for measuring diagnostic X-rays

    NASA Astrophysics Data System (ADS)

    Sharifi, B.; Zamani Zeinali, H.; Soltani, J.; Negarestani, A.; Shahvar, A.

    2015-01-01

    Medical diagnostic equipment, like diagnostic radiology and mammography require a dosimeter with high accuracy for dosimetry of the diagnostic X-ray beam. Ionization chambers are suitable instruments for dosimetry of diagnostic-range X-ray beams because of their appropriate response and high reliability. This work introduces the design and fabrication of a new parallel plate ionization chamber with a PMMA body, graphite-coated PMMA windows (0.5 mm thick) and a graphite-foil central electrode (0.1 mm thick, 0.7 g/cm3 dense). This design improves upon the response characteristics of existing designs through the specific choice of materials as well as the appropriate size and arrangement of the ionization chamber components. The results of performance tests conducted at the Secondary Standard Dosimetry laboratory in Karaj-Iran demonstrated the short and long-term stability, the low leakage current, the low directional dependence, and the high ion collection efficiency of the design. Furthermore, the FLUKA Monte Carlo simulations confirmed the low effect of central electrode on this new ionization chamber response. The response characteristics of the parallel plate ionization chamber presented in this work makes the instrument suitable for use as a standard dosimeter in laboratories.

  10. Laser detection of material thickness

    DOEpatents

    Early, James W. (Los Alamos, NM)

    2002-01-01

    There is provided a method for measuring material thickness comprising: (a) contacting a surface of a material to be measured with a high intensity short duration laser pulse at a light wavelength which heats the area of contact with the material, thereby creating an acoustical pulse within the material: (b) timing the intervals between deflections in the contacted surface caused by the reverberation of acoustical pulses between the contacted surface and the opposite surface of the material: and (c) determining the thickness of the material by calculating the proportion of the thickness of the material to the measured time intervals between deflections of the contacted surface.

  11. 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.

  12. Nonlinear behavior of circular plates with work hardening

    NASA Technical Reports Server (NTRS)

    Winter, R.; Levine, H. S.

    1978-01-01

    Tests were performed on two simply supported plates of aluminum alloy 2024-0, under a central concentrated load, with peak deflections up to 2.6 times the thickness. The load was provided by a small-diameter hard-steel rod. The plates had diameter-to-thickness ratios (D/h) of 20 and 41. Measurements were made of load, deflections and strains; membrane and bending strains were calculated from the test data. The test data are presented in comparison with theoretical predictions generated by the finite-element-computer code PLANS, which includes material and geometric nonlinearities. The theoretical prediction was excellent for deflections, and generally good for strains, when the central force was represented by a line load around the loading rod's contact circle.

  13. Air Entrainment by Contact Lines of a Solid Plate Plunged into a Viscous Fluid Antonin Marchand,1

    E-print Network

    )], typically 10 microns thick. The substrate is sufficiently clean and the vibrations sufficiently low to avoidAir Entrainment by Contact Lines of a Solid Plate Plunged into a Viscous Fluid Antonin Marchand,1 lines is studied by plunging a solid plate into a very viscous liquid. Above a threshold velocity, we

  14. The time-dependent von K\\'arm\\'an plate equation as a limit of 3d nonlinear elasticity

    E-print Network

    Abels, Helmut; Müller, Stefan

    2009-01-01

    The asymptotic behaviour of the solutions of three-dimensional nonlinear elastodynamics in a thin plate is studied, as the thickness $h$ of the plate tends to zero. Under appropriate scalings of the applied force and of the initial values in terms of $h$, it is shown that three-dimensional solutions of the nonlinear elastodynamic equation converge to solutions of the time-dependent von K\\'arm\\'an plate equation.

  15. Toward a generalized plate motion reference frame

    NASA Astrophysics Data System (ADS)

    Becker, T. W.; Schaeffer, A. J.; Lebedev, S.; Conrad, C. P.

    2015-05-01

    An absolute plate motion (APM) model is required to address issues such as the thermochemical evolution of Earth's mantle. All APM models have to rely on indirect inferences, including those based on hot spots and seismic anisotropy, each with their own set of uncertainties. Here, we explore a seafloor spreading-aligned reference frame. We show that this reference frame fits azimuthal seismic anisotropy in the uppermost mantle very well. The corresponding Euler pole is close to those of hot spot reference frames, ridge motion minimizing models, and geodynamic estimates of net rotation and predicts clear trench motion patterns. We conclude that a net rotation pole guided by the spreading-aligned model (at 64°E, 61°S, with moderate rotation of ˜ 0.2 … 0.3°/Myr) could indeed represent a standard, comprehensive reference frame for present-day plate motions with respect to the deep mantle.

  16. Fluorescence reference plate for UV illumination using quantum dots.

    PubMed

    Lee, Deuk-Ju; Kim, Jong-Dae; Kim, Yu-Seop; Song, Hye-Jeong; Park, Chan-Young

    2015-01-01

    Many image acquisition methods of nucleic acids still depend on UV illumination, especially after the electrophoresis when determining the size of the target DNA. Therefore the quality of the UV illuminator in the gel documentation system, and the comparison of the fluorescence detected are crucial. This paper presents a fluorescence standard reference plate using quantum dots compared to the conventional method where an agarose gel containing ethidium bromide is loaded with standard samples. The fluorescence standard reference plate consists of chambers filled with commercially available quantum dots such as phosphor dots. The chamber is made by thermally attaching nylon and polyester, the former on the inside and the latter on the outside, for increased stability. The images of the proposed reference plate were captured more than 2 months in regular intervals. The intensity analysis of the images shows that the proposed reference plate delivers stable fluorescence over a long term period. The proposed reference plate can be utilized to compare the performance of various UV illuminators, or to set a standard fluorescence point for certain analyses. PMID:26684573

  17. 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.

  18. Zone plate lens antennas for millimeter and submillimeter wavelengths

    NASA Technical Reports Server (NTRS)

    Goldsmith, Paul F.

    1992-01-01

    Zone plate lenses are a type of focusing element which function essentially as differential phase shifters, having a relatively few, coarsely quantized phase delays across the incident beam of radiation. The major advantages are ease of fabrication and much reduced thickness, compared to conventional refractive focusing elements. These considerations are both of particular importance for the submillimeter range, in which manufacturing tolerances for curved optical elements can pose significant problems, and where the absorption of readily available dielectric materials is quite large. In this presentation we briefly review the theory of zone plate lens operations, present a relatively simple method for calculating the aperture efficiency of zone plate lenses used as antennas, and show some theoretical and measured results in the 100 GHz range.

  19. Perforation of HY-100 steel plates with long rod projectiles

    SciTech Connect

    Hanchak, S.J.; Altman, B.S.; Forrestal, M.J.

    1993-07-01

    The authors conducted perforation experiments with 4340 steel, rod projectiles and HY-100 steel, target plates at striking velocities between 80 and 370 m/s. Projectiles were machined to nominally 30-mm-diameter and 281-mm-length so they could be launched from a 30-mm-powder gun without sabots. The target plates were rigidly clamped at 305-mm diameter and had a nominal thickness of 10.2 mm. In addition to measuring striking and residual projectile velocities, they obtained back surface framing camera data that showed clearly the plate deformation and plug ejection process. An Imacon 792 camera provided up to 20 frames per experiment with an interframe time duration of 10 {mu}s. The modeling work is in progress, but they present a beam model that exhibits the features observed in the experiments.

  20. Stress and free vibration analyses of multilayered composite plates

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Burton, W. Scott

    1989-01-01

    This paper presents a two-phase computational procedure for the accurate prediction of vibration frequencies, stresses, and deformations in simply supported bidirectional multilayered composite plates. The range of applicability of this procedure in terms of the plate's parameters is determined, and the potential of the proposed procedure for use in conjunction with large-scale finite element modeling of composite structures is discussed. It is shown that the use of the shear correction factors calculated by this procedure extends the range of the validity of the first-order shear deformation theory, used in the first phase of the procedure, to fairly thick multilayered plates with the h/L1 ratio of the order of 0.3.

  1. On the elastic characterization of composite plates with vibration data

    NASA Astrophysics Data System (ADS)

    Ayorinde, Emmanuel O.; Yu, Lin

    2005-05-01

    This paper takes a global look at a method of obtaining the elastic constants of the material of a rectangular plate sample by explicitly inputting the geometrical shapes and frequencies of a sufficient number of experimental vibration modes into a computational procedure that essentially compares experimental frequencies with analytical predictions. There are many aspects of this method that have important bearing on accuracy, ease of use and computational economy. The issues that arise include vibration representation functions, selection of experimental mode shapes and frequencies for analysis, goodness of experimental data, frequency sensitivity of the elastic constants, influence of diagonal modes where relevant, plate thickness, plate aspect ratio, material orthotropy ratio and orientation of reinforcing fibers in laminate composites. Whereas some of these factors have been discussed separately in other works, this paper attempts bring the method completely into focus in one place, with an examination of all the factors believed to influence the efficiency of the method.

  2. Spall behavior of rolled aluminum 5083-H116 plate

    NASA Astrophysics Data System (ADS)

    Whelchel, R. L.; Kennedy, G. B.; Dwivedi, S. K.; Sanders, T. H.; Thadhani, N. N.

    2013-06-01

    The spall properties of rolled Al 5083-H116 plate are investigated using symmetric plate impact experiments over the stress range 1.5-6.2 GPa. Rear free surface velocity measurements made employing Velocity Interferometer System for Any Reflector interferometry reveal velocity profiles with clear signals of the Hugoniot elastic limit (HEL) and velocity pullback, indicative of a transition from elastic to plastic behavior and spalling. Experiments were performed on samples obtained both through the thickness and along all of the three principal axes of the rolled plate. For impact through the thickness, the average values of the HEL and spall strength are 0.43 GPa and 0.81 GPa, respectively. Decreasing the flyer plate and sample thicknesses resulted in an increased spall strength value of 0.95 GPa, while the HEL remained the same. The spall strength along the longitudinal (rolling) direction was 1.06 GPa versus 0.95 GPa for impact along either transverse direction. Spall damage for this impact direction often propagated away from the spall plane in the direction of impact and along the grain boundaries. For impact through the thickness, the fracture surface revealed a mixed mode of ductile and intergranular fracture that was not present for the fracture surface in the other two directions. This mixed fracture mode seems to correspond to a shoulder observed in the free surface velocity traces after the pullback. In all cases, cracked brittle inclusions were observed near the spall damage regions, indicating their role in nucleating voids during spall failure.

  3. Improved Coal-Thickness Measurement

    NASA Technical Reports Server (NTRS)

    Barr, T. A.

    1984-01-01

    Summed signals and dielectric-filled antenna improve measurement. Improved FM radar for measuring thickness of coal seam eliminates spectrum splitting and reduces magnitude of echo from front coal surface.

  4. Plastic buckling of ARALL plates

    NASA Astrophysics Data System (ADS)

    Aboudi, J.; Paley, M.

    The plastic bifurcation buckling loads of ARALL (aramid aluminum laminate) plates are predicted. The plastic behavior of the plate is caused by the significant plasticity effects of the aluminum strips. The critical load level at which the ARALL plate loses its stability is determined from the material properties of the elastoplastic aluminum alloy strips and the elastic unidirectional aramid/epoxy composite layers, in conjunction with their geometric characteristics.

  5. Secondary states of vibrating plates

    SciTech Connect

    Matkowsky, R.J.; Putnick, L.J.; Reiss, E.L.

    1981-08-01

    A previously developed perturbation method is used to obtain a new class of periodic motions for the nonlinear vibrations of rectangular, elastic plates. The dynamic von Karman plate theory is used in the analysis. The new solutions arise by secondary bifurcation from the periodic solutions that bifurcate from the natural frequencies of free vibrations of the linearized plate theory. The new motions are a linear combination of two modes of the linearized theory.

  6. Wind tunnel investigation of a Centaur standard shroud compartment vent from Mach number of 0.70 to 1.96

    NASA Technical Reports Server (NTRS)

    Johns, A. L.; Jones, M. L.

    1975-01-01

    An experimental investigation was conducted in the Lewis Research Center 8- by 6-foot supersonic wind tunnel to determine the vent discharge coefficient for the Centaur standard shroud/liquid hydrogen tank compartment vent. The test was conducted from Mach 0.70 to 1.96 with the vent mounted in a flat plate. Full scale simulated flight hardware, such as the vent, corrugations, aft field joint ring and ice bag clip was used. Air was discharged from a plenum chamber, located on the tunnel sidewall behind the plate, through five 6.35 cm diameter vent orifices into the free stream. Boundary layer thickeners, analytically predicted displacement thickness for the vehicle nominal flight trajectory could be simulated over the Mach number range. The highest vent discharge coefficient for any given Mach number and vent pressure ratio generally occurred at the maximum displacement thickness.

  7. Instability of thick brane worlds

    E-print Network

    Kazuo Ghoroku; Masanobu Yahiro

    2003-06-04

    We examined 5d thick brane worlds constructed by a real scalar field. The solutions are obtained in terms of a simple form of smooth warp factor. For the case of dS brane, we found a disease of the solutions. For example, it is impossible to construct thick-brane worlds with our simple smoothing. This result is independent of supersymmetry or other symmetries.

  8. Decreased cortical thickness in central hypoventilation syndrome.

    PubMed

    Macey, Paul M; Moiyadi, Ammar S; Kumar, Rajesh; Woo, Mary A; Harper, Ronald M

    2012-08-01

    Central hypoventilation syndrome (CHS) is a rare condition characterized by hypoventilation during sleep, reduced ventilatory responsiveness to CO(2) and O(2), impaired perception of air hunger, and autonomic abnormalities. Neural impairments accompany the condition, including structural injury, impaired cerebral autoregulation, and dysfunctional autonomic control. The hypoventilation may induce cortical hypoxic injury, additional to consequences of maldevelopment from PHOX2B mutations present in most CHS subjects. We assessed cortical injury in clinically diagnosed CHS using high-resolution magnetic resonance imaging scans, collected from 14 CHS (mean age ± standard deviation [SD] 17.7 ± 5.0 years; 6 female) and 29 control (mean age ± SD, 17.9 ± 4.3 years; 12 female) subjects. We measured group differences in mean cortical thickness and age-thickness correlations using FreeSurfer software, accounting for age and sex (0.1 false discovery rate). Reduced thickness in CHS appeared in the dorsomedial frontal cortex and anterior cingulate; medial prefrontal, parietal, and posterior cingulate cortices; the insular cortex; anterior and lateral temporal lobes; and mid- and accessory motor strips. Normal age-related cortical thinning in multiple regions did not appear in CHS. The cortical thinning may contribute to CHS cardiovascular and memory deficits and may impair affect and perception of breathlessness. Extensive axonal injury in CHS is paralleled by reduced cortical tissue and absence of normal developmental patterns. PMID:21965438

  9. Glass-bead peen plating

    NASA Technical Reports Server (NTRS)

    Graves, J. R.

    1974-01-01

    Peen plating of aluminum, copper, and nickel powders was investigated. Only aluminum was plated successfully within the range of peen plating conditions studied. Optimum plating conditions for aluminum were found to be: (1) bead/powder mixture containing 25 to 35% powder by weight, (2) peening intensity of 0.007A as measured by Almen strip, and (3) glass impact bead diameter of at least 297 microns (0.0117 inches) for depositing-100 mesh aluminum powder. No extensive cleaning or substrate preparation is required beyond removing loose dirt or heavy oil.

  10. 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.

  11. 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.

  12. The Moho depth map of the European Plate

    NASA Astrophysics Data System (ADS)

    Grad, Marek; Tiira, Timo

    2009-01-01

    The European Plate has a 4.5 Gy long and complex tectonic history. This is reflected in the present-day large-scale crustal structures. A new digital Moho depth map is compiled from more than 250 data sets of individual seismic profiles, 3-D models obtained by body and surface waves, receiver function results and maps of seismic and/or gravity data compilations. We have compiled the first digital, high-resolution map of the Moho depth for the whole European Plate, extending from the mid-Atlantic ridge in the west to the Ural Mountains in the east, and from the Mediterranean Sea in the south to the Barents Sea and Spitsbergen in the Arctic in the north. In general, three large domains within the European Plate crust are visible. The oldest Archean and Proterozoic crust has a thickness of 40-60 km, the continental Variscan and Alpine crust has a thickness of 20-40 km, and the youngest oceanic Atlantic crust has a thickness of 10-20 km.

  13. Vibration of arbitrarily-shaped triangular plates with elastically restrained edges

    NASA Astrophysics Data System (ADS)

    Zhang, X. F.; Li, W. L.

    2015-11-01

    A solution method is proposed for the vibration analysis of arbitrarily-shaped triangular plates with elastically restrained edges. An arbitrarily-shaped triangular plate is first mapped into a right-angled isosceles triangular plate and subsequently "stretched" to form a square plate by padding to it another (right-angled isosceles triangular) plate of near-zero thickness. The displacement function is then expressed as a two-dimensional Fourier cosine series supplemented by several one-dimensional series introduced to improve the convergence and accuracy of the displacement solution. Regardless of the shapes and boundary conditions of the triangular plate, the final stiffness and mass matrices can always be calculated analytically which makes the current solution method highly efficient in implementations. Numerical examples are presented to verify the applicability of the proposed method to triangular plates of different shapes, and, perhaps more importantly, different boundary conditions. The current method can be easily extended to plates with heterogeneous material properties, variable thickness, non-uniform elastic restraints, etc.

  14. 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.

  15. Intermittent plate tectonics?

    PubMed

    Silver, Paul G; Behn, Mark D

    2008-01-01

    Although it is commonly assumed that subduction has operated continuously on Earth without interruption, subduction zones are routinely terminated by ocean closure and supercontinent assembly. Under certain circumstances, this could lead to a dramatic loss of subduction, globally. Closure of a Pacific-type basin, for example, would eliminate most subduction, unless this loss were compensated for by comparable subduction initiation elsewhere. Given the evidence for Pacific-type closure in Earth's past, the absence of a direct mechanism for termination/initiation compensation, and recent data supporting a minimum in subduction flux in the Mesoproterozoic, we hypothesize that dramatic reductions or temporary cessations of subduction have occurred in Earth's history. Such deviations in the continuity of plate tectonics have important consequences for Earth's thermal and continental evolution. PMID:18174440

  16. Plate tectonics, damage and inheritance.

    PubMed

    Bercovici, David; Ricard, Yanick

    2014-04-24

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4?billion years ago) and global tectonics (approximately 3?billion years ago) suggests that plates and plate boundaries became widespread over a period of 1?billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates. PMID:24717430

  17. 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.

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

    E-print Network

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

    2011-01-01

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

  19. 40 CFR 413.74 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Pretreatment standards for existing sources. 413.74 Section 413.74...GUIDELINES AND STANDARDS ELECTROPLATING POINT SOURCE CATEGORY Electroless Plating Subcategory...Pretreatment standards for existing sources. Except as provided in 40...

  20. 40 CFR 413.74 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Pretreatment standards for existing sources. 413.74 Section 413.74...GUIDELINES AND STANDARDS ELECTROPLATING POINT SOURCE CATEGORY Electroless Plating Subcategory...Pretreatment standards for existing sources. Except as provided in 40...

  1. 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.

  2. Non contact probing of interfacial stiffnesses between two plates by Zero-Group Velocity Lamb modes

    E-print Network

    Mezil, Sylvain; Royer, Daniel; Prada, Claire

    2014-01-01

    A non contact technique using Zero-Group Velocity (ZGV) Lamb modes is developed to probe the bonding between two solid plates coupled by a thin layer. The layer thickness is assumed to be negligible compared with the plate thickness and the acoustic wavelength. The coupling layer is modeled by a normal and a tangential spring to take into account the normal and shear interfacial stresses. Theoretical ZGV frequencies are determined for a symmetrical bi-layer structure and the effect of the interfacial stiffnesses on the cut-off and ZGV frequencies are evaluated. Experiments are conducted with two glass plates bonded by a drop of water, oil, or salol, leading to a few micrometer thick layer. An evaluation of normal and shear stiffnesses, is obtained using ZGV resonances locally excited and detected with laser ultrasonic techniques.

  3. Low-cost hydrophobic layer as a top plate in two-plate digital microfluidics

    NASA Astrophysics Data System (ADS)

    Tabatabaeipour, Ghiasadin; Hajghassem, Hassan; MohtashamiFar, Mansoor

    2015-07-01

    Digital microfluidics is an emerging technology that is able to manipulate droplets individually. To develop this technology it is needed to use cheaper and more accessible materials for its fabrication. At present, materials commonly used for the hydrophobic layer in these devices are expensive materials that require a legal agreement. In this paper, polydimethylsiloxane (PDMS), which is a common and cheap material in the field of microfluidic, is used as a hydrophobic material for both top and bottom plates of digital microfluidic devices. The droplet cannot be actuated using DC voltage in a surrounding air environment. The reason for the droplet pinning is the high contact angle hysteresis of PDMS surface and considerable thickness of hydrophobic layer on the top plate. In order to overcome this problem, we have exploited a suitable AC voltage (230 Vrms and 8 kHz) as well as changing the surrounding environment to the olive oil. Therefore this paper demonstrates the feasibility of using PDMS as a hydrophobic layer in two-plate digital microfluidics.

  4. Micro-channel plate detector

    SciTech Connect

    Elam, Jeffrey W.; Lee, Seon W.; Wang, Hsien -Hau; Pellin, Michael J.; Byrum, Karen; Frisch, Henry J.

    2015-09-22

    A method and system for providing a micro-channel plate detector. An anodized aluminum oxide membrane is provided and includes a plurality of nanopores which have an Al coating and a thin layer of an emissive oxide material responsive to incident radiation, thereby providing a plurality of radiation sensitive channels for the micro-channel plate detector.

  5. Metal vapor arc ion plating

    DOEpatents

    Bertram, L.A.; Fisher, R.W.; Mattox, D.M.; Zanner, F.J.

    1986-09-09

    A method and apparatus for ion plating are described. The apparatus uses more negative than a first electrode voltage in a vacuum arc remelt system to attract low energy ions from the anode electrode to the article to be plated. 2 figs.

  6. System for measuring film thickness

    DOEpatents

    Batishko, Charles R. (West Richland, WA); Kirihara, Leslie J. (Richland, WA); Peters, Timothy J. (Richland, WA); Rasmussen, Donald E. (Richland, WA)

    1990-01-01

    A system for determining the thicknesses of thin films of materials exhibiting fluorescence in response to exposure to excitation energy from a suitable source of such energy. A section of film is illuminated with a fixed level of excitation energy from a source such as an argon ion laser emitting blue-green light. The amount of fluorescent light produced by the film over a limited area within the section so illuminated is then measured using a detector such as a photomultiplier tube. Since the amount of fluorescent light produced is a function of the thicknesses of thin films, the thickness of a specific film can be determined by comparing the intensity of fluorescent light produced by this film with the intensity of light produced by similar films of known thicknesses in response to the same amount of excitation energy. The preferred embodiment of the invention uses fiber optic probes in measuring the thicknesses of oil films on the operational components of machinery which are ordinarily obscured from view.

  7. Operation and experience of a 2 km coated conductor REEL - to - REEL copper pulse plating facility

    NASA Astrophysics Data System (ADS)

    Floegel-Delor, U.; Riedel, T.; Wippich, D.; Rothfeld, R.; Schirrmeister, P.; Koenig, R.; Werfel, F. N.; Usoskin, A.; Rutt, A.

    2014-05-01

    Bruker HTS manufactures YBCO based superconducting wires of the second generation on low- cost Stainless Steel substrate (100 ?m thick). With 250 - 500 A/cm@77 K, SF, 650 MPa tensile strength and 6 mm bending radius excellent electrical and mechanical properties are achieved. As complementation of the 2G fabrication technology an automated 2 km copper pulse plating facility has been installed in 2012. We report here the operation requirements and the experiences of the copper plating technique.

  8. Small deflection of a class of clamped thin plates using collocation

    NASA Technical Reports Server (NTRS)

    Worley, W. J.

    1977-01-01

    Equations are given for the optimization of a class of two-and three-dimensional structures. The application of existing analytical techniques to the response of thin clamped plates is described. The ratios of deflections to plate thickness are given for uniform transverse loads as well as for uniform plus linearly varying transverse loads. Deflections are presented at angular increments of 5 degrees and at radial increments of 0.1 of the radius.

  9. On the use of the hole-drilling technique for residual stress measurements in thin plates

    NASA Technical Reports Server (NTRS)

    Hampton, R. W.; Nelson, D. V.

    1992-01-01

    The strain gage blind hole-drilling technique may be used to determine residual stresses at and below the surface of components. In this paper, the hole-drilling analysis methodology for thick plates is reviewed, and experimental data are used to evaluate the methodology and to assess its applicability to thin plates. Data on the effects of gage pattern, surface preparation, hole spacing, hole eccentricity, and stress level are also presented.

  10. Relative motions of the Australian, Pacific and Antarctic plates estimated by the Global Positioning System

    NASA Technical Reports Server (NTRS)

    Larson, Kristine M.; Freymueller, Jeff

    1995-01-01

    Global Positioning System (GPS) measurements spanning approximately 3 years have been used to determine velocities for 7 sites on the Australian, Pacific and Antarctic plates. The site velocities agree with both plate model predictions and other space geodetic techniques. We find no evidence for internal deformation of the interior of the Australian plate. Wellington, New Zealand, located in the Australian-Pacific plate boundary zone, moves 20 +/- 5 mm/yr west-southwest relative to the Australian plate. Its velocity lies midway between the predicted velocities of the two plates. Relative Euler vectors for the Australia-Antarctica and Pacific-Antarctica plates agree within one standard deviation with the NUVEL-1A predictions.

  11. Unique microchannel plate process doubles MCPI resolution

    SciTech Connect

    Thomas, S.; Power, G.

    1994-08-22

    Applying a dielectric layer to the output of a microchannel plate (MCP) has allowed the screen voltage of a sealed microchannel-plate intensifier tube (MCPI) to be raised to over 10 kV, producing a field strength of 36 kV/mm without any detectable field emission or breakdown of the MCP/screen gap. Tube resolution exceeded 16 lp/mm at 50% modulation. Breakdown is higher in a dielectric than in a vacuum. In a concept being patented by Gary Power, a few-{mu}m-thick layer of a dielectric was sputtered onto the output surface of an 18-mm MCP, which was incorporated into a tube under a contract for four tube starts. This process is applicable to any device incorporating a proximity-focused MCP and screen, including streak tubes and gated MCP x-ray imagers. Other improvements discussed include a patented use of a collimator for eliminating the electrons that are elastically scattered from the screen. This method also provides for further improvements in screen gap limited resolution to any desired degree by eliminating electrons with high transverse energy. This occurs at the expense of output brightness, which can be recovered through an appropriate increase in screen voltage.

  12. Present-day plate motions

    NASA Technical Reports Server (NTRS)

    Minster, J. B.; Jordan, T. H.

    1977-01-01

    A data set comprising 110 spreading rates, 78 transform fault azimuths and 142 earthquake slip vectors was inverted to yield a new instantaneous plate motion model, designated RM2. The mean averaging interval for the relative motion data was reduced to less than 3 My. A detailed comparison of RM2 with angular velocity vectors which best fit the data along individual plate boundaries indicates that RM2 performs close to optimally in most regions, with several notable exceptions. On the other hand, a previous estimate (RM1) failed to satisfy an extensive set of new data collected in the South Atlantic Ocean. It is shown that RM1 incorrectly predicts the plate kinematics in the South Atlantic because the presently available data are inconsistent with the plate geometry assumed in deriving RM1. It is demonstrated that this inconsistency can be remedied by postulating the existence of internal deformation with the Indian plate, although alternate explanations are possible.

  13. Convergent plate margin east of North Island, New Zealand

    SciTech Connect

    Davey, F.J; Hampton, M.; Lewis, K.

    1986-07-01

    The Indian-Pacific plate boundary passes along the eastern margin of North Island, New Zealand, with the Pacific plate being thrust under the Indian plate to the west. The continental slope forming the Indian plate margin is broad with a well-formed series of trench slope basins and intervening ridges along the continental slope and shelf, subparallel to the margin, and continuing onto land. Multichannel seismic reflection data recorded across this margin show a thick (2.5-km) sedimentary section overlying oceanic basement in the deep-water part of the profile, and part of this sedimentary section is apparently being subducted under the accretionary prism. At the toe of the continental slope, nascent thrusts, often showing little apparent offset but a change in reflection amplitude, occur over a broad region. Well-defined trench slope basins show several episodes of basin formation and thrusting and are similar to structural interpretations for adjacent onshore basins. A bottom simulating reflector, which may delineate a gas-hydrate layer, can be traced over the midslope part of the profile. A major reflector, interpreted as the base of the accretionary prism, can be traced discontinuously to the coast where it coincides with the top of a zone of high seismicity, considered to mark the top of the subducted Pacific plate.

  14. Fermion localization on thick branes

    SciTech Connect

    Melfo, Alejandra; Pantoja, Nelson; Tempo, Jose David

    2006-02-15

    We consider chiral fermion confinement in scalar thick branes, which are known to localize gravity, coupled through a Yukawa term. The conditions for the confinement and their behavior in the thin-wall limit are found for various different BPS branes, including double walls and branes interpolating between different AdS{sub 5} spacetimes. We show that only one massless chiral mode is localized in all these walls, whenever the wall thickness is keep finite. We also show that, independently of wall's thickness, chiral fermionic modes cannot be localized in dS{sub 4} walls embedded in a M{sub 5} spacetime. Finally, massive fermions in double wall spacetimes are also investigated. We find that, besides the massless chiral mode localization, these double walls support quasilocalized massive modes of both chiralities.

  15. Applications of film thickness equations

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1983-01-01

    A number of applications of elastohydrodynamic film thickness expressions were considered. The motion of a steel ball over steel surfaces presenting varying degrees of conformity was examined. The equation for minimum film thickness in elliptical conjunctions under elastohydrodynamic conditions was applied to roller and ball bearings. An involute gear was also introduced, it was again found that the elliptical conjunction expression yielded a conservative estimate of the minimum film thickness. Continuously variable-speed drives like the Perbury gear, which present truly elliptical elastohydrodynamic conjunctions, are favored increasingly in mobile and static machinery. A representative elastohydrodynamic condition for this class of machinery is considered for power transmission equipment. The possibility of elastohydrodynamic films of water or oil forming between locomotive wheels and rails is examined. The important subject of traction on the railways is attracting considerable attention in various countries at the present time. The final example of a synovial joint introduced the equation developed for isoviscous-elastic regimes of lubrication.

  16. Time delay control of hysteretic composite plate

    NASA Astrophysics Data System (ADS)

    Chen, Long-Xiang; Li, Shi-Hong; Liu, Kun; Cai, Guo-Ping; Li, Hong-Guang

    2015-04-01

    Due to boosting usage of flexible and damping materials, it is of great significance for both science and engineering to explore active control methods for vibration within time-delayed hysteretic structures. This paper conducts theoretical and experimental research on a time-delayed controller for a flexible plate with a single-layer rubber glued on its back. First of all, the dynamic equation for a composite plate is given on the base of the Kirchhoff-Love assumption, where damping-restoring force is described by the Bouc-Wen hysteresis model. Then, the influence of time delay is taken into account and the state equation of the plate with time delay is obtained. Next, a standard state equation, with implicit time delay, is derived using one specific form of integral transformation and vector augmentation. Finally, an instantaneous optimal control method is used to design an active controller. This controller does not only involve state feedback of the current step, but also a linear addition of former state feedbacks within several steps. In order to verify this method, experimental work is conducted. Problems encountered like differential computation and lifting of displacement signal are also handled. According to a comparison between simulations and experiments, the control method given in this paper is feasible and valid, and it is available for both small and large time delay.

  17. Global Plate Velocities from the Global Positioning System

    NASA Technical Reports Server (NTRS)

    Larson, Kristine M.; Freymueller, Jeffrey T.; Philipsen, Steven

    1997-01-01

    We have analyzed 204 days of Global Positioning System (GPS) data from the global GPS network spanning January 1991 through March 1996. On the basis of these GPS coordinate solutions, we have estimated velocities for 38 sites, mostly located on the interiors of the Africa, Antarctica, Australia, Eurasia, Nazca, North America, Pacific, and South America plates. The uncertainties of the horizontal velocity components range from 1.2 to 5.0 mm/yr. With the exception of sites on the Pacific and Nazca plates, the GPS velocities agree with absolute plate model predictions within 95% confidence. For most of the sites in North America, Antarctica, and Eurasia, the agreement is better than 2 mm/yr. We find no persuasive evidence for significant vertical motions (less than 3 standard deviations), except at four sites. Three of these four were sites constrained to geodetic reference frame velocities. The GPS velocities were then used to estimate angular velocities for eight tectonic plates. Absolute angular velocities derived from the GPS data agree with the no net rotation (NNR) NUVEL-1A model within 95% confidence except for the Pacific plate. Our pole of rotation for the Pacific plate lies 11.5 deg west of the NNR NUVEL-1A pole, with an angular speed 10% faster. Our relative angular velocities agree with NUVEL-1A except for some involving the Pacific plate. While our Pacific-North America angular velocity differs significantly from NUVEL-1A, our model and NUVEL-1A predict very small differences in relative motion along the Pacific-North America plate boundary itself. Our Pacific-Australia and Pacific- Eurasia angular velocities are significantly faster than NUVEL-1A, predicting more rapid convergence at these two plate boundaries. Along the East Pacific Pise, our Pacific-Nazca angular velocity agrees in both rate and azimuth with NUVFL-1A.

  18. Earthquake Production by Subduction Zones is Not Linear in Relative Plate Velocity

    NASA Astrophysics Data System (ADS)

    Bird, P.; Kagan, Y. Y.; Jackson, D. D.; Schoenberg, F. P.; Werner, M. J.

    2007-12-01

    The ratio of \\{long-term-average seismic moment production per unit length of plate boundary\\} to \\{relative plate velocity\\} is determined by the "coupled thickness" of seismogenic lithosphere, and also by elastic moduli and geometric factors that are fairly well known. It is generally assumed that coupled thickness is constant within a given class of plate boundary, such as Bird's [2003, G3]: CCB Continental Convergent Boundary, CRB Continental Rift Boundary, CTF Continental Transform Fault, OCB Oceanic Convergent Boundary, OSR Oceanic Spreading Ridge, OTF Oceanic Transform Fault, or SUB Subduction zone. However, Bird et al. [2002, Geodyn. Ser.] and Bird & Kagan [2004, BSSA] found two exceptions: OSR and OTF both have greater coupled thickness at low relative plate velocities. We test for variation of coupled thickness with relative plate velocity in each of the 7 classes of plate boundary. We use shallow (<70 km) earthquakes from the Harvard CMT catalog, 1982.01.01-2007.03.31, above magnitude MW threshold of 5.51 or 5.66. In order to reduce the influence of aftershock swarms, we estimate the probability of independence of each earthquake according to the likelihood stochastic declustering method of Kagan & Jackson [1991; GJI] and use this as a weight. We use the algorithm of Bird & Kagan [2004, BSSA] to assign 95% of shallow earthquakes to plate boundary steps and plate boundary classes, rejecting all earthquakes that fall into one of the 13 orogens of Bird [2003, G3]. We order the plate-boundary steps outside orogens in each class by relative plate velocity according to the PB2002 model of Bird [2003]. Then, we plot cumulative earthquake count as a function of cumulative model tectonic moment (assuming constant coupled thickness and other parameters within each plate boundary class). The null hypothesis is a linear relation; we use 2 measures (Kolmogorov-Smirnov, and Cramer-von Mises) to quantify departures from this line. We use 10,000 simulations of each class with random Poissonian seismicity in each plate boundary step (with expectations based on the tectonic model) to assess the significance of the measures obtained. Subduction zones have velocity-dependent coupled thickness: P < 0.001 for the null hypothesis. Subduction zones with relative plate velocity <67 mm/a (which would comprise 35% of the model tectonic moment rate, in the null hypothesis) actually produce only 20% of the global subduction zone earthquakes (outside orogens), and thus have a coupled thickness about half that of faster subduction zones (if corner magnitude and spectral slope are constant). This result contradicts the uniform coupling of subduction zones inferred by Kreemer et al. [2002, Geodyn. Ser.]; the difference may be due to their exclusion of several slow subduction zones including Aegean, Cascadia, New Zealand, Caribbean, and South Shetland. Continental CCBs show a similarly strong relation (P < 0.001), with an increase in coupled thickness when velocity exceeds 25 mm/a. OSRs show coupled thickness declining with velocity, as in previous studies. OTFs and OCBs give complex results with significant variations (P < 0.01; P < 0.05) that are not easy to interpret. For CRBs and CTFs we do not reject the null hypothesis of constant coupled thickness.

  19. Utilization of orthotropic graphite plates in plate heat exchangers, analytical modeling

    E-print Network

    Bahrami, Majid

    Utilization of orthotropic graphite plates in plate heat exchangers, analytical modeling Farshid Keywords: Orthotropic media Graphite sheet Plate heat exchanger Effectiveness Critical conductivity a b as promising alternative to conventional metallic plate heat exchangers (PHE). A new analytical model

  20. Calibration of Mean Fault Friction and Mantle Driving Tractions for all Plates on Earth

    NASA Astrophysics Data System (ADS)

    Rucker, W.; Bird, P.

    2006-12-01

    The balanced forces (or torques) on each plate have traditionally been divided into poorly-defined categories such as ridge-push, slab-pull, continental-collision resistance, etc. A more rigorous subdivision is into three categories: (1) Lithostatic pressure tractions integrated over all plate boundaries (even if actual pressure is different due to rock strength); (2) Side-strength tractions (due to deviatoric stresses and pressure anomalies) integrated over plate-bounding fault surfaces; (3) Bottom-strength tractions integrated over the bases of plates, including a horizontal reference surface cutting through any attached subducting slab(s). Since these torques add to zero for each plate, computation of lithostatic-pressure torques and estimation of side-strength torques gives an estimate of bottom-strength torque for each plate. If the plate has no subducting slab attached, this bottom-strength torque must be due to shear tractions reflecting relative plate motion over the subjacent mantle. A complication is that plate-boundary fault strength is not well understood or measured. Thus alternative models are possible in which the bottom-strength torques have different magnitudes and directions. Under plates that have no attached slabs, seismic data showing anisotropy due to shearing fabrics help to constrain the the uncertainty. Furthermore, each alternative model (characterized by a trial mean value of effective fault friction) makes different predictions for intraplate deformation rates, relative velocities, and intraplate stress orientations. We are using thin-shell neotectonic modeling program Shells to perform these computations. An Earth5 grid (52 plates; 13 orogens; 2846 fault elements; 26798 continuum elements; 16008 nodes) describes lithospheric structure incorporating ETOPO5 topography, estimated heat flow, CRUST2 crustal thicknesses, and mantle lithosphere thicknesses based on seismic tomography. For each computation, we initially force correct (PB2002) plate velocities with internal boundary conditions located either (a) where subducting slabs have been omitted from the model; or (b) at strong points of low heat-flow in plate interiors. After determining reaction forces, we remove the artificial singularities around points of class (b) by redistributing the same bottom-strength forces as a smooth field of shear tractions for that plate. Each computed model will be compared to 4 data sets: (I) azimuths of seismic anisotropy under slabless plates; (II) intraplate stress directions; (III) relative geodetic velocities; and (IV) rates of sea-floor spreading. While tests III and IV serve primarily to rule out models with excessive intraplate deformation (due to very high effective friction on plate- bounding faults), tests I and II have the potential to identify the optimum mean value.

  1. 40 CFR 426.45 - Standards of performance for new sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.45 Standards of performance for new sources. The...

  2. 40 CFR 426.45 - Standards of performance for new sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.45 Standards of performance for new sources. The...

  3. 40 CFR 426.45 - Standards of performance for new sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.45 Standards of performance for new sources. The...

  4. 40 CFR 426.45 - Standards of performance for new sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Plate Glass Manufacturing Subcategory § 426.45 Standards of performance for new sources. The...

  5. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

    DOEpatents

    Howard, Stanley R. (Windsor, SC); Korinko, Paul S. (Aiken, SC)

    2008-05-27

    A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated layers for brazing alloy, and the stainless steel tube are heated and cooled in a vacuum furnace at controlled rates, forming a bond of the copper foam rings to the stainless steel tube that improves heat transfer between the tube and the copper foam.

  6. Benefits of the Multiple Echo Technique for Ultrasonic Thickness Testing

    SciTech Connect

    Elder, J.; Vandekamp, R.

    2011-02-10

    Much effort has been put into determining methods to make accurate thickness measurements, especially at elevated temperatures. An accuracy of +/- 0.001 inches is typically noted for commercial ultrasonic thickness gauges and ultrasonic thickness techniques. Codes and standards put limitations on many inspection factors including equipment, calibration tolerance and temperature variations. These factors are important and should be controlled, but unfortunately do not guarantee accurate and repeatable measurements in the field. Most technicians long for a single technique that is best for every situation, unfortunately, there are no 'silver bullets' when it comes to nondestructive testing. This paper will describe and discuss some of the major contributors to measurement error as well as some advantages and limitations of multiple echo techniques and why multiple echo techniques should be more widely utilized for ultrasonic thickness measurements.

  7. Bladder wall thickness mapping for magnetic resonance cystography

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Liang, Zhengrong; Zhu, Hongbin; Han, Hao; Duan, Chaijie; Yan, Zengmin; Lu, Hongbing; Gu, Xianfeng

    2013-08-01

    Clinical studies have shown evidence that the bladder wall thickness is an effective biomarker for bladder abnormalities. Clinical optical cystoscopy, the current gold standard, cannot show the wall thickness. The use of ultrasound by experts may generate some local thickness information, but the information is limited in field-of-view and is user dependent. Recent advances in magnetic resonance (MR) imaging technologies lead MR-based virtual cystoscopy or MR cystography toward a potential alternative to map the wall thickness for the entire bladder. From a high-resolution structural MR volumetric image of the abdomen, a reasonable segmentation of the inner and outer borders of the bladder wall can be achievable. Starting from here, this paper reviews the limitation of a previous distance field-based approach of measuring the thickness between the two borders and then provides a solution to overcome the limitation by an electric field-based strategy. In addition, this paper further investigates a surface-fitting strategy to minimize the discretization errors on the voxel-like borders and facilitate the thickness mapping on the three-dimensional patient-specific bladder model. The presented thickness calculation and mapping were tested on both phantom and human subject datasets. The results are preliminary but very promising with a noticeable improvement over the previous distance field-based approach.

  8. Cortical thickness mediates the effect of ?-amyloid on episodic memory

    PubMed Central

    Reed, Bruce R.; Wirth, Miranka; Haase, Claudia M.; Madison, Cindee M.; Ayakta, Nagehan; Mack, Wendy; Mungas, Dan; Chui, Helena C.; DeCarli, Charles; Weiner, Michael W.; Jagust, William J.

    2014-01-01

    Objective: To investigate the associations among ?-amyloid (A?), cortical thickness, and episodic memory in a cohort of cognitively normal to mildly impaired individuals at increased risk of vascular disease. Methods: In 67 subjects specifically recruited to span a continuum of cognitive function and vascular risk, we measured brain A? deposition using [11C] Pittsburgh compound B–PET imaging and cortical thickness using MRI. Episodic memory was tested using a standardized composite score of verbal memory, and vascular risk was quantified using the Framingham Coronary Risk Profile index. Results: Increased A? was associated with cortical thinning, notably in frontoparietal regions. This relationship was strongest in persons with high A? deposition. Increased A? was also associated with lower episodic memory performance. Cortical thickness was found to mediate the relationship between A? and memory performance. While age had a marginal effect on these associations, the relationship between A? and cortical thickness was eliminated after controlling for vascular risk except when examined in only Pittsburgh compound B–positive subjects, in whom A? remained associated with thinner cortex in precuneus and occipital lobe. In addition, only the precuneus was found to mediate the relationship between A? and memory after controlling for vascular risk. Conclusion: These results suggest strong links among A?, cortical thickness, and memory. They highlight that, in individuals without dementia, vascular risk also contributes to cortical thickness and influences the relationships among A?, cortical thickness, and memory. PMID:24489134

  9. Spatial variations in effective elastic thickness in the Western Pacific Ocean and their implications for Mesozoic volcanism

    NASA Astrophysics Data System (ADS)

    Kalnins, L. M.; Watts, A. B.

    2009-08-01

    We have used free-air gravity anomaly and bathymetric data, together with a moving window admittance technique, to determine the spatial variation in oceanic elastic thickness, Te, in the Western Pacific ocean. Synthetic tests using representative seamounts show that Te can be recovered to an accuracy of ± 5 km for plates up to 30 km thick, with increased accuracy of ± 3 km for Te ? 20 km. The Western Pacific has a T e range of 0-50 km, with a mean of 9.4 km and a standard deviation of 6.8 km. The T e structure of the region is dominated by relatively high Te over the Hawaiian-Emperor Seamount Chain, intermediate values over the Marshall Islands, Gilbert Ridge, and Marcus-Wake Guyots, and low values over the Line Islands, Mid-Pacific Mountains, Caroline Islands, Shatsky Rise, Hess Rise, and Musician Seamounts. Plots of Te at sites with radiometric ages suggest that Te is to first order controlled by the age of the lithosphere at the time of loading. In areas that backtrack into the South Pacific Isotopic and Thermal Anomaly (SOPITA), Te may be as low as the depth to the 180 ± 120 °C isotherm at least locally. In the northern part of the study area including the Hawaiian-Emperor Seamount Chain, Te correlates with the depth to 310 ± 120 °C. These best-fitting isotherms imply peak rates of volcanism during 100-120 Ma (Early Cretaceous) and 140-150 Ma (Late Jurassic). The corresponding addition of 8 × 10 6 km 3 and 4 × 10 6 km 3 of volcanic material to the surface of the oceanic crust would result in long-term sea-level rises of 20 m and 10 m respectively. The Late Jurassic volcanic event, like the later Early Cretaceous event, appears to have influenced the tectonic evolution of the Pacific plate convergent boundaries, resulting in increased volcanism and orogenesis.

  10. Designing a license plate.

    PubMed

    Al-Haboubi, M H

    1999-10-01

    The majority of license plates in Saudi Arabia contain a 7-digit code to represent the registration number of vehicles. This information can be difficult to read, memorize, and reproduce in a short period of time, such as in the case of recall of hit-and-run accidents. The study reported proposes a registration code composed of 3 letters and 3 digits. This alphanumeric code can be converted into a numerical value which would give close to 20 million possible permutations, which would cover the projected number of vehicles to the year 2012. The original and proposed designs would give, in addition to two other alphanumeric codes, were tested on 60 participants using computer animations at three exposure times (1, 2, and 3 s). The results of the ANOVA on the errors committed and Sheffe tests reveal a significant difference (alpha = 0.01) between the 7-digit design and the other designs at all time intervals. Validation of the laboratory experiments were conducted on 15 different participants in the field, with similar findings. PMID:10484277

  11. Tectonics of one-plate planets

    SciTech Connect

    Janes, D.M.

    1990-01-01

    A general planetary shell model in spherical coordinates is developed that is capable of treating shells of arbitrary thickness and driving forces of arbitrary breadth. A methodology is then presented for finding the forces exerted on the shell from two processes. A treatment is developed for mantle convection driven by a density anomaly within a viscous mantle. This model is applied to the small moon of Uranus, Miranda, to study the three large coronae which dominate its surface and for which several competing hypotheses were offered, two of which invoked mantle convection driven by density anomalies of opposite sign. A general model is then developed for loading of the lithosphere and the effects of a range of loads breadths and lithosphere thicknesses are examined. The combinations of these two variables are mapped out where classical approximations such as the flat-plate and thin-shell models are applicable as well as the nature and extent of the transition between these two regimes are determined. Finite element modeling is employed to investigate the coronae on Venus, showing that morphological aspects of these features reported in the literature can be produced by flexure of the lithosphere beneath a volcanic load and gravitational sliding of a cooled crust off these volcanic mounds. Independent characteristic topographic profiles are produced for three of the more regular coronae which question how typical the reported morphologies are in the coronae in general.

  12. Natural frequencies of cracked functionally graded material plates by the extended finite element method

    E-print Network

    Natarajan, S; Bordas, S; Rabczuk, T; Kerfriden, P

    2011-01-01

    In this paper, the linear free flexural vibration of cracked functionally graded material plates is studied using the extended finite element method. A 4-noded quadrilateral plate bending element based on field and edge consistency requirement with 20 degrees of freedom per element is used for this study. The natural frequencies and mode shapes of simply supported and clamped square and rectangular plates are computed as a function of gradient index, crack length, crack orientation and crack location. The effect of thickness and influence of multiple cracks is also studied.

  13. Transverse and torsional complex vibration systems for ultrasonic seam welding of metal plates

    PubMed

    Tsujino; Ueoka; Kashino; Sugahara

    2000-03-01

    Transverse and torsional complex vibration systems for ultrasonic seam welding of metal plate specimens, using a 27 kHz complex vibration disk welding tip vibrating in transverse and torsional vibration modes, were studied. Using a complex vibration welding system with a welding tip vibrating in elliptical or circular locus, thick plate specimens can be welded with a more uniform and larger area compared to a conventional ultrasonic welding system. The disk welding tip vibrates in an elliptical or circular locus. The complex vibration system can continuously weld multiple parts of metal plate specimens such as heat sinks with a large number of fins. PMID:10829631

  14. Conditions for Symmetries in the Buckle Patterns of Laminated-Composite Plates

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    2012-01-01

    Conditions for the existence of certain symmetries to exist in the buckle patterns of symmetrically laminated composite plates are presented. The plates considered have a general planform with cutouts, variable thickness and stiffnesses, and general support and loading conditions. The symmetry analysis is based on enforcing invariance of the corresponding eigenvalue problem for a group of coordinate transformations associated with buckle patterns commonly exhibited by symmetrically laminated plates. The buckle-pattern symmetries examined include a central point of inversion symmetry, one plane of reflective symmetry, and two planes of reflective symmetry.

  15. Lamb Wave Transmission Through One-Dimensional Three-Component Fibonacci Composite Plates

    NASA Astrophysics Data System (ADS)

    Chen, Jiu-Jiu; Wang, Qiong; Han, Xu

    Using the finite element method, we have calculated the transmission spectra of Lamb wave modes which propagate in one-dimensional three-component Fibonacci quasiperiodic composite plates made of three different materials, and analyzed the influence of filling fraction, the ratio of the thickness of the plates to the lattice period and especially the number of generations on the band gaps of Lamb wave modes. The band gap splitting depends on the number of generations which is different from those of one-dimensional two-component Fibonacci composite plates. Engineering band gaps can be obtained by turning different parameters and the number of generations.

  16. Applicability of thermal conduction models to mid-plate volcanism: Comments on a paper by Gass et al

    SciTech Connect

    Vogt, P.R.

    1981-02-10

    The proposition that mid-plate ('hot spot') magmatism is strongly discouraged by a combination of thick lithosphere and rapid plate motion is examined empirically on a global basis and found to be inadequate. Although hot spots perhaps tend to 'avoid' cratonic areas, the nonrandom worldwide distribution of hot spots appears primarily to reflect the state of the sublithospheric mantle. Plate thickness or speed is of lesser importance. The high level of African mid-plate volcanism since 25 m.y. B.P. appears to be part of a global pattern controlled by events in the mantle rather than a result of the Africa plate coming to rest over sublithospheric thermal sources about 40 m.y. B.P.

  17. Perforation of HY-100 steel plates with 4340 R{sub c} 38 and T-250 maraging steel rod projectiles

    SciTech Connect

    Forrestal, M.J.; Hanchak, S.J.

    1998-05-25

    The authors conducted perforation experiments with 4340 Rc 38 and T-250 maraging steel, long rod projectiles and HY-100 steel target plates at striking velocities between 80 and 370 m/s. Flat-end rod projectiles with lengths of 89 and 282 mm were machined to nominally 30-mm-diameter so they could be launched from a 30-mm-powder gun without sabots. The target plates were rigidly clamped at a 305-mm-diameter and had nominal thicknesses of 5.3 and 10.5 mm. Four sets of experiments were conducted to show the effects of rod length and plate thickness on the measured ballistic limit and residual velocities. In addition to measuring striking and residual projectile velocities, they obtained framing camera data on the back surfaces of several plates that showed clearly the plate deformation and plug ejection process. They also present a beam model that exhibits qualitatively the experimentally observed mechanisms.

  18. Depositing and alloying on the inner surface of Gasar Cu pores by plating and annealing treatment

    NASA Astrophysics Data System (ADS)

    Du, Ming; Zhang, Hua-wei; Li, Yan-xiang; Liu, Yuan; Chen, Xiang; He, Yun

    2015-07-01

    Depositing and alloying on the inner surface of Gasar Cu pores were realized by plating Zn and subsequent annealing treatment. Influences of cathode current and plating time on alloy layer thickness at different positions along the pore axial direction were investigated. The obtained results showed that alloy layers with different thickness were formed on the overall inner surface of pores. Phase constitution of alloy layers was determined by energy dispersive X-ray analysis and the phase diagram of Cu-Zn. It was found that the generating sequence of alloy phases was ??????. Based on the thickness of each phase measured from field emission scanning electron microscopy images, the relationship between phase thickness and annealing time was obtained.

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

    SciTech Connect

    R. E. Hackenberg, R. M Aikin, Jr., 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, and H. M. Volz

    2007-01-22

    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 {approx}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 various processing stages, including casting, hot rolling, and homogenizing are documented. The as-cast microsegregation assumed the form of an isotropic cellular structure, with an amplitude of 3-15 wt% Nb and 40-50 micron-length scales. Subsequent thermomechanical processing was shown to be sufficient to attain Nb compositional homogeneity on local scales of hundreds of microns. The results of chemical analysis and other characterization methods are given. The principal impurity elements (of the 40+ elements measured) were carbon, boron, oxygen, tantalum, and iron. In all four plates, after homogenization, the Nb distribution across the entire plate cross-section showed minima at the plate faces and a broad maximum in the center, the differential being 0.5-0.7 wt% in U-7.5Nb and 0.2-0.5 wt% in U-5.5Nb. None of the impurity elements showed statistically significant variations between the center 50% of the plate volume vs the outer 25%. These plates were considered nonbanded and compositionally homogeneous for their proposed use because the required tensile, metallographic, and dilatometer specimens could be extracted from the fairly homogeneous center portion of the plate cross-section. Characterization of the phases and their transition temperatures by x-ray diffraction and dilatometry in rapidly quenched specimens from the final product confirmed that the microstructure of this plate material was suitable for the intended aging studies. The as-quenched tensile response from multiple specimens taken from each plate showed some variability, especially in the ultimate tensile strength and elongation to failure. In general, U-5.5Nb has higher strength and less ductility than U-7.5Nb, though both alloys exhibited the double yield behavior characteristic of banded U-6Nb.

  20. Thermal study of interface between the Orbiter cold plate and typical Shuttle spacecraft payload flight electronics

    NASA Technical Reports Server (NTRS)

    Hwangbo, H.; Coyle, M. J.

    1979-01-01

    Spacelab provides a set of Freon line plumbing and cold plates for experiment equipments which are located in the Shuttle pallet and which need active thermal control. The reported study deals with the thermal problem of attaching a Command and Data Handling module with various electronic boxes whose combined footprints on the baseplate are much larger than the cold plate. A description of two modules and the cold plate assembly in the pallet is presented and a thermal model description is provided. The method employed in modeling heat pipes-honey-comb matrix is based upon an effective conductance between the heat pipe vapor and the walls of the heat pipe. The considered thermal models and a computer program are used to perform steady-state thermal analyses. The temperature gradients in the large module baseplate attached to the small cold plate are predicted as a function of the interface plate thickness.