Sample records for plating thickness standards

  1. Elastic stability of thick auxetic plates

    NASA Astrophysics Data System (ADS)

    Lim, Teik-Cheng

    2014-04-01

    Auxetic materials and structures exhibit a negative Poisson’s ratio while thick plates encounter shear deformation, which is not accounted for in classical plate theory. This paper investigates the effect of a negative Poisson’s ratio on thick plates that are subjected to buckling loads, taking into consideration the shear deformation using Mindlin plate theory. Using a highly accurate shear correction factor that allows for the effect of Poisson’s ratio, the elastic stability of circular and square plates are evaluated in terms of dimensionless parameters, namely the Mindlin-to-Kirchhoff critical buckling load ratio and Mindlin critical buckling load factors. Results for thick square plates reveal that both parameters increase as the Poisson’s ratio becomes more negative. In the case of thick circular plates, the Mindlin-to-Kirchhoff critical buckling load ratios and the Mindlin critical buckling load factors increase and decrease, respectively, as the Poisson’s ratio becomes more negative. The results obtained herein show that thick auxetic plates behave as thin conventional plates, and therefore suggest that the classical plate theory can be used to evaluate the elastic stability of thick plates if the Poisson’s ratio of the plate material is sufficiently negative. The results also suggest that materials with highly negative Poisson’s ratios are recommended for square plates, but not circular plates, that are subjected to buckling loads.

  2. Shear deformation in thick auxetic plates

    NASA Astrophysics Data System (ADS)

    Lim, Teik-Cheng

    2013-08-01

    This paper aims to understand the effect of auxeticity on shear deformation in thick plates. Three models for the shear correction factor of plates as a function of Poisson’s ratio were proposed: an analytical model, a cubic fit model and a modified model. Of these three, the cubic fit model exhibits the best accuracy over the entire range of Poisson’s ratio from -1 to 0.5. The extent of shear deformation is herein investigated using the example of uniformly loaded circular plates. It was found that the maximum deformation of such plates based on Mindlin theory approximates to those according to Kirchhoff theory when the Poisson’s ratio of the plate material is highly negative. When the Poisson’s ratio of the plate material is -1 and the edge of the plate is simply supported, the calculation of the maximum deflection by Mindlin theory simplifies into that by Kirchhoff theory. These results suggest that auxeticity reduces shear deformation in thick plates, permitting the use of classical plate theory for thick plates only if the plate material is highly auxetic.

  3. Thermoelastic buckling behavior of thick functionally graded rectangular plates

    Microsoft Academic Search

    M. Bodaghi; A. R. Saidi

    2011-01-01

    Thermoelastic buckling behavior of thick rectangular plate made of functionally graded materials is investigated in this article.\\u000a The material properties of the plate are assumed to vary continuously through the thickness of the plate according to a power-law\\u000a distribution. Three types of thermal loading as uniform temperature raise, nonlinear and linear temperature distribution through\\u000a the thickness of plate are considered.

  4. Behaviors of moiré fringes induced by plate thickness

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  5. 49 CFR 179.300-6 - Thickness of plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...with material having tensile strength at least equal to the base plate, the cladding may be considered a part of the base plate when determining the thickness. If cladding material does not have tensile strength at least equal to the base...

  6. 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.

  7. Modelling ultrasound guided wave propagation for plate thickness measurement

    NASA Astrophysics Data System (ADS)

    Malladi, Rakesh; Dabak, Anand; Murthy, Nitish Krishna

    2014-03-01

    Structural Health monitoring refers to monitoring the health of plate-like walls of large reactors, pipelines and other structures in terms of corrosion detection and thickness estimation. The objective of this work is modeling the ultrasonic guided waves generated in a plate. The piezoelectric is excited by an input pulse to generate ultrasonic guided lamb waves in the plate that are received by another piezoelectric transducer. In contrast with existing methods, we develop a mathematical model of the direct component of the signal (DCS) recorded at the terminals of the piezoelectric transducer. The DCS model uses maximum likelihood technique to estimate the different parameters, namely the time delay of the signal due to the transducer delay and amplitude scaling of all the lamb wave modes due to attenuation, while taking into account the received signal spreading in time due to dispersion. The maximum likelihood estimate minimizes the energy difference between the experimental and the DCS model-generated signal. We demonstrate that the DCS model matches closely with experimentally recorded signals and show it can be used to estimate thickness of the plate. The main idea of the thickness estimation algorithm is to generate a bank of DCS model-generated signals, each corresponding to a different thickness of the plate and then find the closest match among these signals to the received signal, resulting in an estimate of the thickness of the plate. Therefore our approach provides a complementary suite of analytics to the existing thickness monitoring approaches.

  8. Exact vibration analysis of variable thickness thick annular isotropic and FGM plates

    Microsoft Academic Search

    E. Efraim; M. Eisenberger

    2007-01-01

    Annular plates are used in many engineering structures. In many cases variable thickness is used in order to save weight and improve structural characteristics. In recent years functionally graded materials (FGM) are used in many engineering applications. A FGM plate is an inhomogeneous composite made of two constituents (usually ceramic and metal), with both the composition and the material properties

  9. Propagation of thickness-twist waves in elastic plates with periodically varying thickness and phononic crystals.

    PubMed

    Zhu, Jun; Chen, Weiqiu; Yang, Jiashi

    2014-09-01

    We study the propagation of thickness-twist (TT) waves in a crystal plate of AT-cut quartz with periodically varying, piecewise constant thickness. The scalar differential equation by Tiersten and Smythe is employed. The problem is found to be mathematically equivalent to the motion of an electron in a periodic potential field governed by Schrodinger's equation. An analytical solution is obtained. Numerical results show that the eigenvalue (frequency) spectrum of the waves has a band structure with allowed and forbidden bands. Therefore, for TT waves, plates with periodically varying thickness can be considered as phononic crystals. The effects of various parameters on the frequency spectrum are examined. PMID:24924785

  10. On the propagation of long thickness-stretch waves in piezoelectric plates.

    PubMed

    Huang, Dejin; Yang, Jiashi

    2014-07-01

    We study the propagation of thickness-stretch waves in a piezoelectric plate of polarized ceramics with thickness poling or crystals of class 6 mm whose sixfold axis is along the plate thickness. For device applications we consider long waves with wavelengths much longer than the plate thickness. A system of two-dimensional equations in the literature governing thickness-stretch, extensional, and symmetric thickness-shear motions of the plate is further simplified. The equations obtained can be used to analyze piezoelectric plate acoustic wave devices operating with thickness-stretch modes. PMID:24582557

  11. 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.

  12. 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.

  13. Plate coating: influence of concentrated surfactants on the film thickness.

    PubMed

    Delacotte, Jérôme; Montel, Lorraine; Restagno, Frédéric; Scheid, Benoît; Dollet, Benjamin; Stone, Howard A; Langevin, Dominique; Rio, Emmanuelle

    2012-02-28

    We present a large range of experimental data concerning the influence of surfactants on the well-known Landau-Levich-Derjaguin experiment where a liquid film is generated by pulling a plate out of a bath. The thickness h of the film was measured as a function of the pulling velocity V for different kinds of surfactants (C(12)E(6), which is a nonionic surfactant, and DeTAB and DTAB, which are ionic) and at various concentrations near and above the critical micellar concentration (cmc). We report the thickening factor ? = h/h(LLD), where h(LLD) is the film thickness obtained without a surfactant effect, i.e., as for a pure fluid but with the same viscosity and surface tension as the surfactant solution, over a wide range of capillary numbers (Ca = ?V/?, with ? being the surfactant solution viscosity and ? its surface tension) and identify three regimes: (i) at small Ca ? is large due to confinement and surface elasticity (or Marangoni) effects, (ii) for increasing Ca there is an intermediate regime where ? decreases as Ca increases, and (iii) at larger (but still small) Ca ? is slightly higher than unity due to surface viscosity effects. In the case of nonionic surfactants, the second regime begins at a fixed Ca, independent of the surfactant concentration, while for ionic surfactants the transition depends on the concentration, which we suggest is probably due to the existence of an electrostatic barrier to surface adsorption. Control of the physical chemistry at the interface allowed us to elucidate the nature of the three regimes in terms of surface rheological properties. PMID:22283676

  14. Copper enrichment in arc magmas controlled by overriding plate thickness

    NASA Astrophysics Data System (ADS)

    Chiaradia, Massimo

    2014-01-01

    Porphyry copper systems supply about 75% of the world's copper. They form above subduction zones and are preferentially associated with calc-alkaline magmas. Such magmas result from continuous iron depletion during differentiation, in contrast to tholeiitic magmas that show initial iron enrichment during differentiation. The formation of calc-alkaline magmas is favoured by high water content and oxygen fugacity. These characteristics, as well as magmatic metal contents, are thought to be imparted in the mantle source by fluids of the subducted slab. Yet this process does not explain why porphyry copper systems preferentially occur in thicker arcs. Here I present a statistical assessment of more than 40,000 published geochemical analyses of magmatic rocks from 23 Quaternary-aged volcanic arcs worldwide. I find that magmas of thicker arcs are systematically more calc-alkaline and more depleted in copper than magmas of thinner arcs. This implies that the missing copper in the former accumulates as copper sulphides within or at the base of thicker arcs. Such copper accumulations are an essential step in forming porphyry systems. These results suggest that the thickness of the overriding plate provides a more important control on magma differentiation than the composition of the mantle source, and can explain the preferential association of porphyry copper systems with calc-alkaline magmas and thicker arcs.

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

    Microsoft Academic Search

    Wu Lanhe

    2004-01-01

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

  16. 46 CFR 32.59-1 - Minimum section modulus and plating thickness requirements-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  17. Free vibration of stepped thickness rectangular plates using spectral finite element method

    NASA Astrophysics Data System (ADS)

    Wang, Gang; Unal, Ahmet

    2013-09-01

    Free vibration of stepped thickness rectangular plates is investigated in this paper using the spectral finite element method (SFEM). It is impossible to obtain closed-form solutions for a uniform rectangular plate with arbitrary boundary conditions except the Levy-type plates, i.e., at least simply-supported at two opposite edges. Moreover, the variation of plate thickness adds complexity to the problem. The Kantorovich method is employed to obtain an analytical approximation solution form. Then, a plate spectral finite element is developed accordingly in the frequency domain. Similar to the conventional finite element method (CFEM), after assembling elements and applying boundary conditions, each modal frequency and associated mode shape function can be determined by iteratively solving corresponding equations in plate x and y directions. Available literature results along with NASTRAN simulations are used to validate our SFEM predictions of stepped thickness plates with various boundary conditions. Compared to the CFEM, only a fraction of the mesh is needed to achieve comparable accuracy in each mode. Substantial computation cost can then be saved. Mode shape functions are extracted and presented in a semi-analytical form. Physical insights of wave propagation characteristics in a stepped thickness rectangular plate can be collected from these results. In summary, an efficient and accurate SFEM is developed to conduct free vibration analysis of stepped thickness rectangular plates with various boundary conditions. Assume the mnth plate mode shape function with a separation of variables form W(x,y,?)=?i=1NxX(x,?)Yn(y,?)={

  18. Tactile discrimination of thickness

    Microsoft Academic Search

    K. T. John; A. W. Goodwin; I. Darian-Smith

    1989-01-01

    The ability of human subjects to discriminate plane metal plates of different thickness was measured using a forced-choice paradigm. The plates, made by electroplating a thin layer of copper onto flat brass shims, were gripped between the thumb and the index finger. Subjects were presented with either 2 standard plates (0.2 mm thick), or a standard plate and a test

  19. A Bending-Gradient theory for thick laminated plates homogenization

    E-print Network

    Paris-Sud XI, Université de

    with the second-order approximation of the exact solution as the slenderness ratio L/h goes to infinity. 1 model. How- ever, it is well-known that, when the plate slenderness ratio L/h is not large enough-Kirchhoff strain fields have clearly been identified as good first-order approximation for slender plates thanks

  20. Use of standard specimens in coating thickness measurement

    Microsoft Academic Search

    V. V. Kazantsev; V. P. Eltyshev

    1981-01-01

    cal unit for thickness or surface density. Correspondingly, the standard specimens for coatings in check schemes for means of measurement take over from the standard and working means of measurement normally used for this purpose. The standard specimens used in the field of working means of measurement are assigned by organizations (in-house standard specimens). This is the most numerous class

  1. 49 CFR 179.300-6 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...that calculated by the following formula: EC13NO91.037 Where: d = inside diameter in inches; E = 1.0 welded joint efficiency; P = minimum required bursting pressure in psig; S = minimum tensile strength of plate...

  2. 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.

  3. Thickness measurement of non-magnetic plates using multi-frequency eddy current sensors

    Microsoft Academic Search

    W. Yin; A. J. Peyton

    2007-01-01

    A robust feature in multi-frequency eddy current (MEC) testing has been found that can be directly linked to the thickness of the plate under test. It is shown mathematically that the peak frequency of the imaginary part of the inductance change when an air-cored coil is placed next to a non-magnetic metallic plate is inversely proportional to the thickness of

  4. A Bending-Gradient model for thick plates, Part I: Theory A. Lebee, K. Sab*

    E-print Network

    Paris-Sud XI, Université de

    -order approximation of the exact solution as the slenderness ratio L/h goes to infinity. Key words: Plate Theory slenderness ratio L/h (h is the plate thickness and L the span) is not large enough, out-of-plane stresses

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

    SciTech Connect

    Ohta, Yoshiki; Narita, Yoshihiro [Hokkaido Inst. of Tech., Hokkaido (Japan). Dept. of Mechanical Engineering

    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.

  6. Estimating the convergence rate for eigenfrequencies of anisotropic plates with variable thickness

    NASA Astrophysics Data System (ADS)

    Nazarov, Serguei A.

    Estimates of the differences between rescaled eigenvalues of the spectral problem for a thin anisotropic plate and eigenvalues of its two-dimensional models are obtained with bounds expressed in terms of the plate's thickness and attributes of the limit eigenvalue. To cite this article: S.A. Nazarov, C. R. Mecanique 330 (2002) 603-607.

  7. Three-Dimensional transient heat conduction in a functionally graded thick plate with a higher-order plate theory and a meshless local Petrov-Galerkin method

    Microsoft Academic Search

    L. F. Qian; R. C. Batra

    2005-01-01

    We analyze transient heat conduction in a thick functionally graded plate by using a higher-order plate theory and a meshless local Petrov-Galerkin (MLPG) method. The temperature field is expanded in the thickness direction by using Legendre polynomials as basis functions. For temperature prescribed on one or both major surfaces of the plate, modified Lagrange polynomials are used as basis and

  8. Buckling Analysis of Rectangular Plates with Variable Thickness Resting on Elastic Foundation

    NASA Astrophysics Data System (ADS)

    Viswanathan, K. K.; Navaneethakrishnan, P. V.; Aziz, Z. A.

    2015-01-01

    Buckling of rectangular plates of variable thickness resting in elastic foundation is analysed using a quintic spline approximation technique. The thickness of the plate varies in the direction of one edge and the variations are assumed to be linear, exponential and sinusoidal. The plate is subjected to in plane load of two opposite edges. The buckling load and the mode shapes of buckling are computed from the eigenvalue problem that arises. Detailed parametric studies are made with different boundary conditions and the results are presented through the diagram and discussed.

  9. Thermomechanical postbuckling analysis of moderately thick functionally graded plates and shallow shells

    Microsoft Academic Search

    J. Woo; S. A. Meguid; J. C. Stranart; K. M. Liew

    2005-01-01

    In this paper, an analytical solution is provided for the postbuckling behaviour of moderately thick plates and shallow shells made of functionally graded materials (FGMs) under edge compressive loads and a temperature field. The material properties of the functionally graded shells are assumed to vary continuously through the thickness of the shell, according to a power law distribution of the

  10. Laser Based Measurement of Plate Thickness Using a Fundamental Antisymmetric Mode of Lamb Wave

    NASA Astrophysics Data System (ADS)

    Salim, Muhammad Nor; Hayashi, Takahiro; Murase, Morimasa; Ito, Toshihiro; Kamiya, Shoji

    2010-02-01

    A guided wave technique for measurement of remaining thickness distribution is presented for the purpose of maintenance of large structures like oil storage tanks and pipe networks. This study used a laser source to excite the guided wave at many locations on aluminum plates with defect that have high ratio of A0 mode transmission and small mode conversions. The A0 mode was used to interrogate the through-thickness over the rastered areas in the test plates. It was expected that many modes of Lamb wave were excited in intact and defect regions of the plates through the thermoelastic stresses from the laser source. The fundamental antisymmetric mode A0 was extracted to indicate the thickness distribution in aluminum test plates with the defect. The results exhibit greater amplitude distributions of A0 mode over thinner regions around defects and smaller amplitudes distributions over the intact regions.

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

    E-print Network

    Ballentine, John Richard

    1951-01-01

    have aided in distortino the patterns. The cent, er drivinr& bolt, miEht have aligged slightly on a. few of the plates cnd the agglicat, ion of the thrust could have been slightly off- centcr causinl-. ' s. distorted patt. em, The effect... analog miEht be set, up for a network calculator with the x'esults from it to be ohecked by the same method. of approach used in tLils invest, it. t. ion, with the ch~es list, ed. in the precoedinC; are?rsphs. LL method of appx'o-. ch t, o pxo...

  12. Static and dynamic deformations of thick functionally graded elastic plates by using higher-order shear and normal deformable plate theory and meshless local Petrov–Galerkin method

    Microsoft Academic Search

    L. F. Qian; R. C. Batra; L. M. Chen

    2004-01-01

    Static deformations, and free and forced vibrations of a thick rectangular functionally graded elastic plate are analyzed by using a higher-order shear and normal deformable plate theory (HOSNDPT) and a meshless local Petrov–Galerkin (MLPG) method. All components of the stress tensor are computed from equations of the plate theory. The plate material, made of two isotropic constituents, is assumed to

  13. Standardized palmar plating of dorsally displaced distal radius fractures.

    PubMed

    Löw, Steffen; Herold, Dirk; Eingartner, Christoph

    2013-06-01

    With the inauguration of fixed-angle plates, palmar plating has become a widely accepted way to treat dorsally displaced distal radius fractures. The technique by which the plate is applied to the radius varies. Such plates are primarily fixed either distally or at the proximal limbs. In this article, the standardized technique by which osteosynthesis is conducted in our institution is described step by step. The plate is first fixed to the shaft. Reduction is temporarily maintained by K-wires that run through the plate's distal margin. These K-wires are usually reliable in maintaining adequate reduction and are gradually replaced by locking screws in the distal row. Of 96 consecutive procedures, the duration of operation, the amount of fluoroscopy needed, and the intraoperative radiographic results are reported. Using this method, constantly good results can be achieved, even if the operation is done by less experienced surgeons. PMID:23689859

  14. Eliminating the effect of plate thickness variation in ultrasonic images using a single transducer method

    NASA Astrophysics Data System (ADS)

    Roth, Don J.

    1996-11-01

    This article describes a single transducer ultrasonic imaging method based on ultrasonic velocity measurement that eliminates the effect of plate thickness variation in the image, i.e. the method is thickness-independent. The method, currently being commercialized under a cooperative agreement between NASA Lewis Research Center and Sonix, Inc., thus isolates ultrasonic variations due to material microstructure. Its use can result in significant cost savings because the ultrasonic image can be interpreted correctly without the need for precision thickness machining during nondestructive evaluation stages of material development. Images obtained using the thickness-independent methodology are compared with apparent velocity maps and c- scan echo peak amplitude images for monolithic ceramic and metal matrix composite materials having thickness and microstructural variations. It was found that he thickness- independent ultrasonic images reveal and quantify correctly areas of global microstructural variation due to the elimination of thickness effects.

  15. Resonant frequency function of thickness-shear vibrations of rectangular crystal plates.

    PubMed

    Wang, Ji; Yang, Lijun; Pan, Qiaoqiao; Chao, Min-Chiang; Du, Jianke

    2011-05-01

    The resonant frequencies of thickness-shear vibrations of quartz crystal plates in rectangular and circular shapes are always required in the design and manufacturing of quartz crystal resonators. As the size of quartz crystal resonators shrinks, for rectangular plates we must consider effects of both length and width for the precise calculation of resonant frequency. Starting from the three-dimensional equations of wave propagation in finite crystal plates and the general expression of vibration modes, we obtained the relations between frequency and wavenumbers. By satisfying the major boundary conditions of the dominant thickness-shear mode, three wavenumber solutions are obtained and the frequency equation is constructed. It is shown the resonant frequency of thickness-shear mode is a second-order polynomial of aspect ratios. This conforms to known results in the simplest form and is applicable to further analytical and experimental studies of the frequency equation of quartz crystal resonators. PMID:21622066

  16. 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.

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

    NASA Technical Reports Server (NTRS)

    Forman, R. G.

    1974-01-01

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

  18. A Bending-Gradient model for thick plates, Part II: Closed-form solutions for cylindrical bending of laminates

    E-print Network

    Paris-Sud XI, Université de

    coincides with the second-order approximation of the exact solution as the slenderness ratio L/h goes model. However, it is well-known that, when the plate slenderness ratio L/h (h is the plate thickness

  19. 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.

  20. 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

    2014-10-01

    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.

  1. 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.

  2. THE FINITE ELEMENT ANALYSIS OF THICKNESS-SHEAR VIBRATIONS OF QUARTZ CRYSTAL PLATES WITH ANSYS

    E-print Network

    Wang, Ji

    , with the sophistication of general purpose finite element software such as ANSYS, ABAQUS, NASTRAN, and lately COSMOL545 THE FINITE ELEMENT ANALYSIS OF THICKNESS-SHEAR VIBRATIONS OF QUARTZ CRYSTAL PLATES WITH ANSYS}@nbu.edu.cn, shijun1236@163.com Finite element analysis is a powerful approach to the vibration analysis

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

    Microsoft Academic Search

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

    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,

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

    E-print Network

    Paris-Sud XI, Université de

    more experimental data to be used. Numerical modes (frequencies, dampings, and modal shapesMeasurement of relevant elastic and damping material properties in sandwich thick-plates Marc R to measure relevant elastic and damping properties of the constituents of a sandwich structure, possibly

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

    E-print Network

    Shyamasundar, R.K.

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

  6. Ultrasonic Determination of Temperature Distribution in Thick Plates during Single Sided Heating

    NASA Astrophysics Data System (ADS)

    Takahashi, Manabu; Ihara, Ikuo

    A new ultrasonic method for determining temperature distribution of a thick plate being heated is presented. The principle of the method is based on temperature dependence of ultrasound velocity in heated materials. An inverse analysis method coupled with a finite difference calculation has been developed to determine one-dimensional temperature distribution in the heated plate. To demonstrate the feasibility of the developed method, a single side of a steel plate of 30 mm thickness is heated by contact with molten aluminum at 700°C and ultrasonic pulse-echo measurements are then performed for the steel during heating. The transit time of ultrasound of the heated steel is acquired and used to determine the transient variation of temperature distribution of the steel. The ultrasonically determined results almost agree with those measured using thermocouples installed in the steel.

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

    PubMed

    Waag, Grunde; Hoff, Lars; Norli, Petter

    2015-02-01

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

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

    NASA Astrophysics Data System (ADS)

    Hasheminejad, Seyyed M.; Keshavarzpour, Hemad

    2013-09-01

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

  9. Equivalent network representation for thickness vibration modes in piezoelectric plates with a linearly graded parameter.

    PubMed

    Yamada, K; Sakamura, J; Nakamura, K

    2001-03-01

    Equivalent network representation is derived for thickness vibration modes in piezoelectric plates with a linearly graded parameter. The network is composed of a transmission line of a finite length, which is linked to the electric excitation port via ideal transformers connected serially at both ends. The ratios of the two transformers are different from each other and frequency dependent. Two frequency-dependent capacitors of the same value but opposite sign appear at the electric port. The frequency characteristic of the input electric admittance of the resonator, which shows the unique feature of the graded piezoelectric plate, is demonstrated by the equivalent network analysis. PMID:11370376

  10. Choosing the best geometries for the linear characterization of lossy piezoceramics: Study of the thickness-poled shear plate

    NASA Astrophysics Data System (ADS)

    Pardo, L.; Montero de Espinosa, F.; García, A.; Brebøl, K.

    2008-04-01

    Resonance modes of a thickness-poled piezoceramic shear plate are studied. When determining material properties from impedance measurements, it is required to obtain an uncoupled shear resonance. The shear resonance, which is electrically excited, results to a series of plate resonances, which is mechanically excited by this, when frequencies match. Thus, the condition of a high aspect ratio of the plate is not valid to eliminate coupling. Instead, the thickness (t) and lateral dimensions (L,w) of the plate must be tailored for each material. This approach was tested for a commercial piezoceramic and plates amenable for characterization obtained for aspect ratios below L :t=15:1 (L=w).

  11. 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.

  12. The thermal effect of metal electrodes on thickness-shear vibrations of crystal plates.

    PubMed

    Wang, Ji; Du, Jianke; Shen, Lijun; Yang, Zhihua

    2007-11-01

    The effectiveness of theoretical approaches based on the initial thermal field on vibrations elastic solids has been demonstrated by a series of analyses concerning the thermal behavior of crystal resonators with results in good agreement with measurements. These equations have been implemented in a finite-element method in addition to simple analytical solutions we are familiar with. Starting with an infinite plate under a temperature increase in both crystal and metal layers, the frequency equation based on incremental thermal field formulation is obtained and solved analytically for thickness-shear vibrations with electrodes of different metals and configuration. Numerical examples show that the thermal effect of thicker electrodes on frequency-temperature relations of thickness-shear vibrations of AT-cut quartz crystal plates are generally positive and should be considered in the design process. PMID:18051167

  13. 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.

  14. Effect of elastic foundation on the vibration of orthotropic elliptic plates with varying thickness

    Microsoft Academic Search

    N. Bhardwaj; A. P. Gupta; K. K. Choong

    2007-01-01

    Two-dimensional boundary characteristic orthonormal polynomials are used in the Rayleigh–Ritz method to study the free vibration\\u000a of rectangular orthotropic elliptic plates resting on a Winkler elastic foundation. Two types of varying thickness are considered:\\u000a (1) linearly varying with respect to the concentric ellipses, (2) linearly varying along both the principal axes simultaneously.\\u000a Numerical results for frequencies are presented in tables.

  15. 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.

  16. 75 FR 75186 - License Plate Reader Standard Special Technical Committee Request for Proposals for Certification...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-02

    ...Justice Programs [OJP (NIJ) Docket No. 1535] License Plate Reader Standard Special Technical Committee Request for Proposals for...NIJ) is in the process of developing a new License Plate Reader Standard and corresponding certification program...

  17. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  20. Elastostatic Deformations of a Thick Plate by using a Higher-Order Shear and Normal Deformable Plate Theory and two Meshless Local Petrov-Galerkin (MLPG) Methods

    Microsoft Academic Search

    L. F. Qianl; R. C. Batra; L. M. Chen

    We use two meshless local Petrov-Galerkin formulations, namely, the MLPG1 and the MLPG5, to analyze infinitesimal deformations of a homogeneous and isotropic thick elastic plate with a higher-order shear and normal deformable plate theory. It is found that the two MLPG formulations give results very close to those obtained by other researchers and also by the three- dimensional analysis of

  1. Influence of stack plate thickness and voltage input on the performance of loudspeaker-driven thermoacoustic refrigerator

    NASA Astrophysics Data System (ADS)

    Putra, Nandy; Agustina, Dinni

    2013-04-01

    A loudspeaker-driven thermoacoustic refrigerator has been built and tested to gain understanding of its thermal performance and the cooling rate. The influence of plate thickness made of acrylic sheet was experimentally investigated by varying plate thickness of the stack, 0.15 mm, 0.5 mm and 1 mm, respectively. The experiments were conducted with various voltage input to the driver starting from setting 4 to 9 voltage peak-to-peak. The temperatures at both ends of the stack were acquired. For all variations, thermoacoustic cooling effect occurred in seconds and escalated rapidly in two minutes and became stable in ten-minute time. The experimental results showed that higher voltage input yielded higher thermal performance and faster cooling rate. For each set of experiment, the operating frequency and other parameters of the stack were kept unchanged. The experimental results show that the thermal performance and cooling rate increase with the decrease of plate thickness. The largest temperature difference, 14.8°C, was achieved with 0.1 mm plate thickness at voltage setting 9. However, the thermal performance gained for 0.5 mm plate thickness voltage setting of 9, was arguably the optimum thickness in terms of advantages in the ease of fabricating the stack and more consistent cooling.

  2. 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.

  3. Analysis of method for measuring thickness of plane-parallel plates and lenses using chromatic confocal sensor.

    PubMed

    Miks, Antonin; Novak, Jiri; Novak, Pavel

    2010-06-10

    Noncontact optical metrology based on the chromatic confocal principle is becoming increasingly important for fast and accurate measurements of surface topography, distance, and layer thickness in engineering and industry. These sensors are based on the wavelength dependence of longitudinal chromatic aberration of optical systems, and the distance or thickness of the measured sample is coded into spectral information. We provide a theoretical analysis of a problem of the thickness measurement of transparent samples (glass plane-parallel plates or lenses) with respect to material dispersion. Our work deals with a description and analysis of induced measurement errors in the cases of measurement of the thickness of a plane-parallel plate and the central thickness of a lens. Relations are derived for a quantitative evaluation of these errors and a method is presented for minimizing the influence of these errors on the accuracy of measurement. PMID:20539342

  4. Heat Transfer -2 A heat generating ( ) flat plate fuel element of thickness 2L is covered with flat plate steel cladding of

    E-print Network

    Virginia Tech

    with flat plate steel cladding of thickness b. The heat generated is removed by a fluid at T, which adjoins on both sides On the sketch show regions where dT/dx is zero, constant and increasing. T , h x LL bb SteelSteel

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

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  7. 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.

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

    E-print Network

    Lo, Tzu-Wei

    2005-11-01

    wave dispersion obtained corresponding to the following ranges of parameters: 300-500kHz for frequency, 25-300oC for temperature, 1-3mm for plate thickness, and 6 10 1?? - 7 1 10 ?? N/m for pressure. Each of the three parameters considered in the study...

  9. 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 for Aircraft...comments amending the emission standards for turbine engine powered airplanes to incorporate...The EPA also proposed adopting the gas turbine engine test procedures of the...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

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

  11. 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

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

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

  14. Numerical modeling and measurement by pulsed television holography of ultrasonic displacement maps in plates with through-thickness defects

    NASA Astrophysics Data System (ADS)

    López-Vázquez, J. Carlos; Deán-Ben, X. Luís; Trillo, Cristina; Doval, Ángel F.; Fernández, José L.; Amlani, Faisal; Bruno, Oscar P.

    2010-09-01

    We present a novel numerical modeling of ultrasonic Lamb and Rayleigh wave propagation and scattering by through-thickness defects like holes and slots in homogeneous plates, and its experimental verification in both near and far field by a self-developed pulsed TV holography system. In contrast to rigorous vectorial formulation of elasticity theory, our model is based on the 2-D scalar wave equation over the plate surface, with specific boundary conditions in the defects and plate edges. The experimental data include complex amplitude maps of the out-of-plane displacements of the plate surface, obtained by a two-step spatiotemporal Fourier transform method. We find a fair match between the numerical and experimental results, which allows for quantitative characterization of the defects.

  15. 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.

  16. Magnitude and phase spectral analysis of through-transmitted ultrasound pulses for the determination of the ultrasound velocity and the thickness of solid plates

    NASA Astrophysics Data System (ADS)

    Gómez Álvarez-Arenas, Tomás E.

    2010-01-01

    A method that combines transmission of air-coupled ultrasound pulses through solid plates and magnitude and phase spectral analysis is presented. The purpose is to determine, simultaneously, velocity and attenuation coefficient of the ultrasounds in the material, and the thickness and the density of the plate. This is especially useful when thickness can not be measured independently and it is necessary to obtain estimations for the velocity and the attenuation coefficient of ultrasounds in the plate.

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

    NASA Astrophysics Data System (ADS)

    Mao, Jie; Li, Ming-Xuan; Wang, Xiao-Min

    2007-03-01

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

  18. Effect of interlayer thickness on shear deformation behavior of AA5083 aluminum alloy\\/SS41 steel plates manufactured by explosive welding

    Microsoft Academic Search

    Jun Hyun Han; Jae Pyoung Ahn; Myung Chul Shin

    2003-01-01

    An AA5083 aluminum alloy plate and an SS41 steel plate were cladded by an explosive welding method using an AA1050 aluminum alloy interlayer plate. The effects of the interlayer thickness on the interface morphology and the shear deformation behavior of the cladded plates were studied. The interfacial zone was composed of an intermetallic compound, FeAl3, formed by the AA1050 interlayer.

  19. Automated agar plate streaker: a linear plater on Society for Biomolecular Sciences standard plates.

    PubMed

    King, Gregory W; Kath, Gary S; Siciliano, Sal; Simpson, Neal; Masurekar, Prakash; Sigmund, Jan; Polishook, Jon; Skwish, Stephen; Bills, Gerald; Genilloud, Olga; Peláez, Fernando; Martín, Jesus; Dufresne, Claude

    2006-09-01

    Several protocols for bacterial isolation and techniques for aerobic plate counting rely on the use of a spiral plater to deposit concentration gradients of microbial suspensions onto a circular agar plate to isolate colony growth. The advantage of applying a gradient of concentrations across the agar surface is that the original microbiological sample can be applied at a single concentration rather than as multiple serial dilutions. The spiral plater gradually dilutes the sample across a compact area and therefore saves time preparing dilutions and multiple agar plates. Commercial spiral platers are not automated and require manual sample loading. Dispensing of the sample volume and rate of gradients are often very limited in range. Furthermore, the spiral sample application cannot be used with rectangular microplates. Another limitation of commercial spiral platers is that they are useful only for dilute, filtered suspensions and cannot plate suspensions of coarse organic particles therefore precluding the use of many kinds of microorganism-containing substrata. An automated agar plate spreader capable of processing 99 rectangular microplates in unattended mode is described. This novel instrument is capable of dispensing discrete volumes of sample in a linear pattern. It can be programmed to dispense a sample suspense at a uniform application rate or across a decreasing concentration gradient. PMID:16844965

  20. Technique for Measurements of Elastic Wave Velocities and Thickness of Solid Plate from Access on Only One Side

    NASA Astrophysics Data System (ADS)

    Kim, Young H.; Song, Sung-Jin; Lee, Jeong-Ki

    2005-07-01

    A novel method is proposed for the simultaneous measurement of longitudinal and transverse wave velocities and the thickness of isotropic solid plates from access on only one side. Line contact transducers were placed on the same side of the specimen, and waveforms were acquired at various distances between the transducers. Longitudinal wave velocity and the thickness of the specimen can be simultaneously determined from the relationship between the transit time of the longitudinal wave mode and the ultrasonic beam path. A least-squares fitting method was employed to increase the accuracy of measurements. Transverse wave velocity also can be determined from the transit time of the mode-converted transverse wave and the corresponding beam path determined by Snell’s law. Experimental results for several specimens of different materials as well as different thicknesses show good agreement with those measured by conventional methods.

  1. Evaluation of Thickness Reduction in a Thin Plate Using a Non-Contact Guided Wave Technique

    NASA Astrophysics Data System (ADS)

    Song, Won-Joon; Park, Ik-Keun; Kim, Tae-Hyung; Kim, Hyun-Mook; Kim, Yong-Kwon; Cho, Yong-Sang

    2006-03-01

    Ultrasonic guided waves are widely being studied and successfully applied to various non-destructive tests with the advantage of a long range inspection. Recently, non-contact methods are also adopted and combined with the guided wave techniques. In this paper, an advanced technique for the nondestructive detection of thinning defects simulating hidden corrosion in thin plates using non-contact guided waves is presented. The proposed approach uses EMAT(Electro-Magnetic Acoustic Transducer) for the non-contact generation and detection of guided plate waves in aluminum plates. Interesting features of the dispersive behavior in selected wave modes are used for the detection of plate thinning. The experimental results show that the mode cutoff measurements provide a qualitative measurement of thinning defects and change in the mode group velocity can be used as quantitative parameter of thinning depth measurement.

  2. Variation of crack-opening stresses in three-dimensions - Finite thickness plate

    NASA Technical Reports Server (NTRS)

    Chermahini, R. G.; Blom, A. F.

    1991-01-01

    A 3D elastic-plastic finite-element analysis is conducted to study crack-growth behavior of thin and thick center-cracked specimens under constant-amplitude loading conditions. The numerical analysis and the specimen configuration and loading are described for both the thin and thick conditions. Stabilized crack-opening stresses of interior and exterior regions are given as are the closure and opening profiles of the crack-surface plane after the tenth cycle. The effect of thickness is discussed with respect to the crack-opening stress levels and the plastic zones of the interior and exterior regions. A load-reduced-displacement technique allows the calculation of the crack-opening stresses at three locations on the crack surface plane. The constraint effect related to thickness gives a lower stabilized crack-opening stress level for the thick specimens.

  3. Coating thickness affects surface stress measurement of brush electro-plating nickel coating using Rayleigh wave approach.

    PubMed

    Liu, Bin; Dong, Shiyun; Xu, Binshi; He, Peng

    2012-09-01

    A surface ultrasonic wave approach was presented for measuring surface stress of brush electro-plating nickel coating specimen, and the influence of coating thickness on surface stress measurement was discussed. In this research, two Rayleigh wave transducers with 5MHz frequency were employed to collect Rayleigh wave signals of coating specimen with different static tensile stresses and different coating thickness. The difference in time of flight between two Rayleigh wave signals was determined based on normalized cross correlation function. The influence of stress on propagation velocity of Rayleigh wave and the relationship between the difference in time of flight and tensile stress that corresponded to different coating thickness were discussed. Results indicate that inhomogeneous deformation of coating affects the relationship between the difference in time of flight and tensile stress, velocity of Rayleigh wave propagating in coating specimen increases with coating thickness increasing, and the variation rate reduces of difference in time of flight with tensile stress increasing as coating thickness increases. PMID:22534060

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

    SciTech Connect

    Dong, Liang; Li, Shuhui [Shanghai Key Laboratory of Digital Manufacture for Thin-walled Structures, Shanghai Jiao Tong University, Shanghai 200240 (China); Yang, Bing; Gao, Yongsheng [Automotive Steel Research Institute, R and D Center, BaoShan Iron and Steel Co.,Ltd, Shanghai 201900 (China)

    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.

  5. Asymptotic analysis of an arbitrary anisotropic plate of variable thickness (sloping shell)

    SciTech Connect

    Nazarov, S A [St. Petersburg State University, St. Petersburg (Russian Federation)

    2000-08-31

    The leading terms of the asymptotics of the solution of the problem of elasticity theory for a thin plane with curved bases are constructed; in addition, the resulting problem (a two-dimensional model) is written out explicitly. Arbitrary anisotropy of elastic properties is allowed; moreover, these properties may depend on the 'rapid' transversal and the 'slow' longitudinal variables. The substantiation of these asymptotics is carried out on the basis of Korn's weighted inequality. The cases of laminated plates, sloping shells, and plates with sharp edges are discussed separately.

  6. Plate motion and dragging of the upper mantle - Lateral variations of lithospheric thickness and their implications for intraplate deformation

    NASA Astrophysics Data System (ADS)

    Sabadini, Roberto; Giunchi, Carlo; Gasperini, Paolo; Boschi, Enzo

    1992-04-01

    The impact of lateral variations in the thickness of the lithosphere on surface topography, horizontal intraplate deformation and stress accumulation is studied for plates that drift with respect to the highly viscous lower mantle and the transition zone. The lithosphere and upper mantle are described by a viscoelastic Maxwell rheology within the frame-work of a finite element scheme which allows the modeling of heterogeneous lithospheric structures in 2D vertical cross sections. The geophysical signatures are found to be extremely sensitive to lateral viscosity contrasts which interact with the upper mantle flow. This mechanism can contribute to a certain extent and in concert with the other driving forces of plate tectonics to the evolution of back-arc basins, to the explanation of the largest angle of subduction in west-dipping slabs and to the initiation of subduction of an oceanic lithosphere underneath a stable continental one.

  7. An approximate semi-analytical method for prediction of interlaminar shear stresses in an arbitrarily laminated thick plate

    NASA Technical Reports Server (NTRS)

    Chaudhuri, Reaz A.; Seide, Paul

    1987-01-01

    An approximate semianalytical method for determination of interlaminar shear stress distribution through the thickness of an arbitrarily laminated thick plate has been presented. The method is based on the assumptions of transverse inextensibility and layerwise constant shear angle theory (LCST) and utilizes an assumed quadratic displacement potential energy based finite element method (FEM). Centroid of the triangular surface has been proved from a rigorous mathematical point of view (Aubin-Nitsche theory), to be the point of exceptional accuracy for the interlaminar shear stresses. Numerical results indicate close agreement with the available three-dimensional elasticity theory solutions. A comparison between the present theory and that due to an assumed stress hybrid FEM suggest that the (normal) traction-free-edge condition is not satisfied in the latter approach. Furthermore, the present paper is the first to present the results for interlaminar shear stresses in a two-layer thick square plate of balanced unsymmetric angle-ply construction. A comparison with the recently proposed Equilibrium Method (EM) indicates the superiority of the present method, because the latter assures faster convergence as well as simultaneous vanishing of the transverse shear stresses on both of the exposed surfaces of the laminate. Superiority of the present method over the EM, in the case of a symmetric laminate, is limited to faster convergence alone. It has also been demonstrated that the combination of the present method and the reduced (quadratic order) numerical integration scheme yields convergence of the interlaminar shear stresses almost as rapidly as that of the nodal displacements, in the case of a thin plate.

  8. 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 for Aircraft...action amends the emission standards for turbine engine powered airplanes to incorporate...The EPA also proposed adopting the gas turbine engine test procedures of ICAO. The...

  9. Short Communication Thickness vibration of piezoelectric plates of 6 mm crystals with tilted six-fold

    E-print Network

    Wang, Ji

    ­5]. AlN and ZnO plates with the six-fold axis normal, in-plane or tilted [3] with re- spected on the electric potential, but their mechanical effects like stiffness and inertia are neglected. While the thin- fects of electrode stiffness or inertia need to be considered. This is especially true for FBARs because

  10. A finite-element approach to solving a thermal conductivity problem for thick plates

    Microsoft Academic Search

    B. L. Bozhenko

    1993-01-01

    A method is proposed for the numerical solution of a problem in the thermal conductivity a plate heated by a moving heat source, taking into account the dependence of the thermal properties of the material on temperature. A hypothesis of N. N. Rykalin concerning the state of the thermal field is adopted. The method is based on a spline variant

  11. Longitudinal change in femorotibial cartilage thickness and subchondral bone plate area in male and female adolescent vs. mature athletes.

    PubMed

    Eckstein, Felix; Boeth, Heide; Diederichs, Gerd; Wirth, Wolfgang; Hudelmaier, Martin; Cotofana, Sebastian; Hofmann-Amtenbrink, Margarethe; Duda, Georg

    2014-05-01

    Little is known about changes in human cartilage thickness and subchondral bone plate area (tAB) during growth. The objective of this study was to explore longitudinal change in femorotibial cartilage thickness and tAB in adolescent athletes, and to compare these data with those of mature former athletes. Twenty young (baseline age 16.0 ± 0.6 years) and 20 mature (46.3 ± 4.7 years) volleyball athletes were studied (10 men and 10 women in each group). Magnetic resonance images were acquired at baseline and at year 2-follow-up, and longitudinal changes in cartilage thickness and tAB were determined quantitatively after segmentation. The yearly increase in total femorotibial cartilage thickness was 0.8% (95% confidence interval [CI]: -0.5; 2.1%) in young men and 1.4% (95% CI: 0.7; 2.2%) in young women; the gain in tAB was 0.4% (95% CI: -0.1; 0.8%) and 0.7% (95% CI: 0.2; 1.2%), respectively (no significant difference between sexes). The cartilage thickness increase was greatest in the medial femur, and was not significantly associated with the variability in tAB growth (r=-0.19). Mature athletes showed smaller gains in tAB, and lost >1% of femorotibial cartilage per annum, with the greatest loss observed in the lateral tibia. In conclusion, we find an increase in cartilage thickness (and some in tAB) in young athletes toward the end of adolescence. This increase appeared somewhat greater in women than men, but the differences between both sexes did not reach statistical significance. Mature (former) athletes displayed high rates of (lateral) femorotibial cartilage loss, potentially due to a high prevalence of knee injuries. PMID:24439995

  12. 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.

  13. An ultrasonic method for determination of elastic moduli, density, attenuation and thickness of a polymer coating on a stiff plate.

    PubMed

    Lavrentyev, A I; Rokhlin, S I

    2001-04-01

    An ultrasonic method proposed by us for determination of the complete set of acoustical and geometrical properties of a thin isotropic layer between semispaces (J. Acoust. Soc. Am. 102 (1997) 3467) is extended to determination of the properties of a coating on a thin plate. The method allows simultaneous determination of the coating thickness, density, elastic moduli and attenuation (longitudinal and shear) from normal and oblique incidence reflection (transmission) frequency spectra. Reflection (transmission) from the coated plate is represented as a function of six nondimensional parameters of the coating which are determined from two experimentally measured spectra: one at normal and one at oblique incidence. The introduction of the set of nondimensional parameters allows one to transform the reconstruction process from one search in a six-dimensional space to two searches in three-dimensional spaces (one search for normal incidence and one for oblique). Thickness, density, and longitudinal and shear elastic moduli of the coating are calculated from the nondimensional parameters determined. The sensitivity of the method to individual properties and its stability against experimental noise are studied and the inversion algorithm is accordingly optimized. An example of the method and experimental measurement for comparison is given for a polypropylene coating on a steel foil. PMID:11350002

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

    E-print Network

    Wang, Ji

    the weighted error to vanish, we have obtained a nonlinear ordinary differential equation depending on time also employed the perturbation method to solve this ordinary differential equation and obtained attempts to study nonlinear effects of thickness-shear vibrations for the various purposes. Equations

  15. 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...

  16. Analytical and numerical methods for vibration analysis of thick rectangular plates by modified Mindlin theory

    NASA Astrophysics Data System (ADS)

    Senjanovi?, I.; Hadži?, N.; Tomi?, M.; Vladimir, N.; Cho, D. S.

    2014-10-01

    Total deflection and angles of rotations in the Mindlin plate theory are decomposed into bending and transverse shear deflection, bending rotations and in-plane shear angles. Single differential equation of flexural vibrations is derived in terms of bending deflection as potential function for determination of all displacements and sectional forces. The equation is solved analytically for different combinations of boundary conditions. Shear locking-free rectangular finite element is formulated. Illustrative examples are solved analytically and numerically, and the obtained results are compared with the ones available in the relevant literature.

  17. 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.

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-01

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

  19. 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

  20. Investigation of trapped thickness-twist waves induced by functionally graded piezoelectric material in an inhomogeneous plate

    NASA Astrophysics Data System (ADS)

    Li, Peng; Jin, Feng; Cao, Xiao-Shan

    2013-09-01

    The effect of functional graded piezoelectric materials on the propagation of thickness-twist waves is investigated through equations of the linear theory of piezoelectricity. The elastic and piezoelectric coefficients, dielectric permittivity, and mass density are assumed to change in a linear form but with different graded parameters along the wave propagation direction. We employ the power-series technique to solve the governing differential equations with variable coefficients attributed to the different graded parameters and prove the correction and convergence of this method. As a special case, the functional graded middle layer resulting from piezoelectric damage and material bonding is investigated. Piezoelectric damaged material can facilitate energy trapping, which is impossible in perfect materials. The increase in the damaged length and the reduction in the piezoelectric coefficient decrease the resonance frequency but increase the number of modes. Higher modes of thickness-twist waves appear periodically along the damaged length. Moreover, the displacement of the center of the damaged portion is neither symmetric nor anti-symmetric, unlike the non-graded plate. The conclusions are theoretically and practically significant for wave devices.

  1. 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.

  2. On standardization of the plate impact experiment for polymeric and metallic materials

    Microsoft Academic Search

    Y. Sato; K. Nishimura

    2006-01-01

    A modified Unsteady-Wave-Sensing-System (M-UWSS) is proposed to standardize of the plate impact experiment combined with in-material gauges in the target specimen for two kinds of materials, i.e. polymeric and metallic materials. The M-UWSS has some unique features as follows: (1) Nanosecond Lagrangian analyses are used to extract strain-time histories from experimental stress data. (2) A new charge mode which measures

  3. 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

    Microsoft Academic Search

    Steven C. Cohen; Desmond J. Darby

    2003-01-01

    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

  4. An analysis of residual stress patterns resulting from hole expansion in an infinite plate, a thick cylinder, and an asymmetric lug

    NASA Astrophysics Data System (ADS)

    Walker, C. A.; McKelvie, J.; Hyzer, J. B.

    1997-05-01

    Residual stresses were induced in three specimen geometries: a quasiinfinite plate, a thick cylinder and an asymmetric lug. In each case, a hole expansion process was used, whereby the bore was expanded into the plastic regime; this in effect left residual compression at the bore and residual tension in the far field. In view of the symmetry, the stress patterns in the quasi-infinite plate were measured by a hole drilling method, using an interferometric moiré method to measure the resulting strain patterns. In the case of the thick cylinder and the asymmetric lug, the residual stresses were evidenced by a dissection method. A comparison with theoretical treatments shows that the theory predicts an approximate upper bound to the actual stress levels in the quasi-infinite plate. In the lug geometry, there was a similar systematic difference between theory and experiment.

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

    SciTech Connect

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

    2011-08-15

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

  6. On the relationship between statistical distributions of defect size and fatigue life in 7050-T7451 thick plate and A356-T6 castings

    Microsoft Academic Search

    Murat Tiryakio?lu

    2009-01-01

    The relationship between the distributions for the size of fatigue-initiating defects and fatigue life of 7050-T7451 thick plate and A356-T6 alloy castings reported previously in the literature were analyzed. Results showed that (i) the size of fatigue-initiating defects in all four datasets follow the Gumbel distribution, (ii) the fatigue life model based on the Paris-Erdo?an law for crack propagation provides

  7. Development of a standard reference material for diesel mutagenicity in the Salmonella plate incorporation assay.

    PubMed

    Hughes, T J; Lewtas, J; Claxton, L D

    1997-07-14

    The present study documents the mutagenicity of a new National Institute of Standards and Technology (NIST) standard reference material (SRM) in the Salmonella plate incorporation assay. This study is in response to a previous recommendation by the World Health Organization to develop large batches of new SRMs for biological and chemical research. SRM 1975 is a dichloromethane (DCM) extract of 5.6 kg of filter-collected combustion particulate matter (SRM 2975) from operating forklifts with diesel engines. The mutagenicity and a summary of the related chemical analysis of mutagens in SRM 1975 is presented in this paper, and are available from the NIST. Mutagenicity test conditions were: Salmonella typhimurium TA98, TA100 (standard strains); TA98NR, TA100NR (nitroreductase (NR) gene deficient); and YG1021 and YG1026 (NR gene addition); 10 dose levels in the linear portion of the dose-response curve; duplicate plates per dose; and S9 at 6.4% or 1.1 mg of protein/plate. Four rounds of testing were conducted. Rounds were conducted at least 1 week apart. Slopes (revertants/microg) were calculated by the linear regression rejection model of Bernstein and by the Stead and Krewski models which analyze non-linear data. The GeneTox Manager software package developed at the EPA was used to record the data and calculate the slopes. Results demonstrated: (1) the ranking of slopes without S9 was: YG1021 > TA98 > TA98NR > YG1026 > TA100 > TA100NR in all three statistical models; (2) the mutagenic activity of SRM 1975 was significantly increased by the presence of the NR gene; (3) the slope values for the TA100 series were significantly less than for the TA98 series; (4) in general, the addition of the S9 significantly reduced mutagenic activity; (5) the mutagenic activity of the SRM 1975 was stable over time and variability was low (generally less than 20% in slope values over the 4 rounds); and (6) agreement of the slope values among the three models was excellent due to the linear nature of the data. These data will be useful in ranking other diesel and air samples for mutagenic activity, for quality assurance of data generated in different laboratories, for quality control within a laboratory, and as positive control values for future air and automotive emission studies. PMID:9268049

  8. Free and Forced Vibrations of Thick Rectangular Plates using Higher-Or~er Shear and Normal Deformable Plate Theory and Meshless Petrov-Galerkin (MLPG) Method

    Microsoft Academic Search

    L. F. Qianl; R. C. Batra; L. M. Chenl

    2003-01-01

    We use a meshless local Petrov-Galerkin Liu (2001) have used the MLPG method to find natu- (MLPG) method to analyze three-dimensional infinitesi- ral frequencies and forced plane ,strain deformations.of mal elastodynamic deformations of a homogeneous rect- a cantilever beam. Batra and Chmg .(2002~ have de!m- angular plate subjected to different edge conditions. We eated the time evolution of the stress-mtenslty

  9. Simple Method for Plating Escherichia coli Bacteriophages Forming Very Small Plaques or No Plaques under Standard Conditions

    Microsoft Academic Search

    J. M. Los; Piotr Golec; G. Wegrzyn; A. Wegrzyn; M. Los

    2008-01-01

    The use of low concentrations (optimally 2.5 to 3.5 g\\/ml, depending on top agar thickness) of ampicillin in the bottom agar of the plate allows for formation of highly visible plaques of bacteriophages which otherwise form extremely small plaques or no plaques on Escherichia coli lawns. Using this method, we were able to obtain plaques of newly isolated bacteriophages, propagated

  10. TWO DIMENSIONAL ANALYSIS OF THIN SHELL OR PLATE-LIKE MUFFLER ELEMENTS OF NON-UNIFORM THICKNESS

    Microsoft Academic Search

    P. C.-C. Lai; W. Soedel

    1996-01-01

    A general procedure for the analysis of curved, thin muffler elements, which can efficiently utilize the limited space in hermetically sealed compressors or compact engine installations [1], is extended to take non-uniform thickness into account. The inhomogeneous 2-D wave equation for the non-uniform thickness case is derived in two dimensional curvilinear coordinates defined on a curved surface by the application

  11. 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.

  12. Fluids Mechanics -1 Consider a circular plate of outer radius Ro (a portion of which is shown in the figure). A fluid filled gap of thickness h(t)

    E-print Network

    Virginia Tech

    Fluids Mechanics - 1 Consider a circular plate of outer radius Ro (a portion of which is shown in the figure). A fluid filled gap of thickness h(t) exists between the bottom of the plate and the flat surface that the fluid filling the gap is incompressible, inviscid and its motion is irrotational. Also assume the radial

  13. Plate Tectonics

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2007-03-21

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

  14. Experimental analysis of thermal performance of flat plate and evacuated tube solar collectors in stationary standard and daily conditions

    Microsoft Academic Search

    E. Zambolin; D. Del Col

    2010-01-01

    New comparative tests on two different types of solar collectors are presented in this paper. A standard glazed flat plate collector and an evacuated tube collector are installed in parallel and tested at the same working conditions; the evacuated collector is a direct flow through type with external compound parabolic concentrator (CPC) reflectors. Efficiency in steady-state and quasi-dynamic conditions is

  15. Subcellular in vivo time-lapse imaging and optical manipulation of Caenorhabditis elegans in standard multiwell plates

    Microsoft Academic Search

    Christopher B. Rohde; Mehmet Fatih Yanik

    2011-01-01

    High-resolution in vivo time-lapse assays require repeated immobilization and imaging of whole animals. Here we report a technology for screening Caenorhabditis elegans at cellular resolution over its entire lifespan inside standard multiwell plates using repeated immobilization, imaging and optical manipulation. Our system does not use any fluidic or mechanical components, and can operate for tens of thousands of cycles without

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

    Microsoft Academic Search

    P. Corcoran; L. Bynoe

    2010-01-01

    Quartz arenites are significant components of the rock record and appear to be most abundant during specific time intervals in Earth history. Thick quartz arenite successions are typical in Precambrian strata and have been associated with extensive cratonization during the late Archean to early Proterozoic. These supermature sandstones can also be attributed to the intense weathering conditions of early Earth's

  17. 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.

  18. Piezoelectric coupling factor calculations for plates of langatate driven in simple thickness modes by lateral-field-excitation.

    PubMed

    Khan, Ajmal; Ballato, Arthur

    2002-07-01

    Piezoelectric coupling factors for langatate (La3Ga5.5Ta0.5O14) single-crystals driven by lateral-field-excitation have been calculated using the extended Christoffel-Bechmann method. Calculations were made using published materials constants. The results are presented in terms of the lateral piezoelectric coupling factor as functions of in-plane (azimuthal) rotation angle for the three simple thickness vibration modes of some non-rotated, singly-rotated, and doubly-rotated orientations. It is shown that lateral-field-excitation offers the potential to eliminate unwanted vibration modes and to achieve considerably greater piezoelectric coupling versus thickness-field-excitation for the rotated cuts considered and for a doubly-rotated cut that is of potential technological interest. PMID:12152946

  19. "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.

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

    NASA Astrophysics Data System (ADS)

    Corcoran, P.; Bynoe, L.

    2010-12-01

    Quartz arenites are significant components of the rock record and appear to be most abundant during specific time intervals in Earth history. Thick quartz arenite successions are typical in Precambrian strata and have been associated with extensive cratonization during the late Archean to early Proterozoic. These supermature sandstones can also be attributed to the intense weathering conditions of early Earth’s atmosphere, source rocks rich in quartz, recycling and diagenesis, or simply the higher preservation potential of quartz compared with other minerals. Modern quartz-rich sands develop in low relief settings where high residence times contribute to chemical breakdown of labile grains. The lack of land vegetation during the Precambrian would have precluded confined sedimentation patterns and stabilization of soils, both of which enhance sediment residence times. Thus, the generation of first-cycle late Archean quartz arenites in fault-controlled, high relief basins necessitates periods of intense chemical weathering. The inferred change from a greenhouse to oxygenated atmosphere at around 2.3-2.2 Ga could have been the major control on the relative change to thinner units of pure sandstones with time. In order to test this hypothesis, detailed facies and compositional analyses are being conducted on the ca. 2.2 Ga Bar River Formation of the Huronian Supergroup, Canada. Four groups comprise Huronian stratigraphy, three of which contain basal glaciogenic conglomerates, followed by mudstone-dominated then quartz-rich formations. It has been suggested that these tripartite cycles could have been climatically controlled. Detailed facies analysis of the 500-750 m thick quartz arenite indicates shallow water, wave-influenced settings, akin to shoreface environments along extensive stable shelves. Thin mudstone interbeds, representing brief periods of suspension sedimentation, have been sampled for geochemical analysis in order to determine the degree of chemical weathering that occurred. Preliminary investigations of heavy mineral suites have indicated an abundance of the stable minerals zircon and tourmaline, which is consistent with physical and chemical weathering. Depending on preservation, detailed examination of quartz and heavy mineral surface textures and grain boundaries using SEM could provide an idea of the relative degree of recycling versus chemical erosion that has occurred. Finally, the Bar River Formation is primarily exposed as the “core” of a string of islands stretching approximately 40 km within Lake Huron. Preservation of the quartz arenite, but not the over- and underlying formations reflects how it better withstands billions of years of weathering and erosion compared with other less pure sedimentary rocks. Thus the apparent abundance of thick ancient quartz arenite relative to younger examples may simply be a function of mineral stability.

  1. 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

    ...received one comment concerning the amended rule. Comment: One comment was received from a semiconductor wafer and photovoltaic (PV) cell manufacturer who performs electroless nickel plating onto silicon wafers in clean rooms or segregated...

  2. Experimental analysis of thermal performance of flat plate and evacuated tube solar collectors in stationary standard and daily conditions

    Microsoft Academic Search

    E. Zambolin; D. Del Col

    2010-01-01

    New comparative tests on two different types of solar collectors are presented in this paper. A standard glazed flat plate collector and an evacuated tube collector are installed in parallel and tested at the same working conditions; the evacuated collector is a direct flow through type with external compound parabolic concentrator (CPC) reflectors.Efficiency in steady-state and quasi-dynamic conditions is measured

  3. Real time monitoring of electroless nickel plating

    NASA Astrophysics Data System (ADS)

    Rains, Aaron E.; Kline, Ronald A.

    2013-01-01

    This work deals with the design and manufacturing of the heat and chemical resistant transducer case required for on-line immersion testing, experimental design, data acquisition and signal processing. Results are presented for several depositions with an accuracy of two ten-thousandths of an inch in coating thickness obtained. Monitoring the deposition rate of Electroless Nickel (EN) plating in-situ will provide measurement of the accurate dimensions of the component being plated, in real time. EN is used as for corrosion and wear protection for automotive an - Electroless Nickel (EN) plating is commonly used for corrosion and wear protection for automotive and aerospace components. It plates evenly and symmetrically, theoretically allowing the part to be plated to its final dimension. Currently the standard approach to monitoring the thickness of the deposited nickel is to remove the component from the plating bath and physically measure the part. This can lead to plating problems such as pitting, non-adhesion of the deposit and contamination of the plating solution. The goal of this research effort is to demonstrate that plating thickness can be rapidly and accurately measured using ultrasonic testing. Here a special housing is designed to allow immersion of the ultrasonic transducers directly into the plating bath. An FFT based signal processing algorithm was developed to resolve closely spaced echoes for precise thickness determination. The technique in this research effort was found to be capable of measuring plating thicknesses to within 0.0002 inches. It is expected that this approach will lead to cost savings in many EN plating operations.

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

    NASA Astrophysics Data System (ADS)

    Sharkov, Evgenii

    2010-05-01

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

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

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2010-01-01

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

  6. 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).

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

    NASA Technical Reports Server (NTRS)

    Simon, F.

    1975-01-01

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

  8. Gel microbead cultivation with a subenrichment procedure can yield better bacterial cultivability from a seawater sample than standard plating method

    NASA Astrophysics Data System (ADS)

    Ji, Shiqi; Zhao, Rui; Yin, Qi; Zhao, Yuan; Liu, Chenguang; Xiao, Tian; Zhang, Xiaohua

    2012-03-01

    A gel microbead (GMD) cultivation method was employed to cultivate microorganisms from an amphioxus breeding zone in Qingdao, P. R. China. The culture results were compared with those by standard plating method. In the GMD-based method, the microcolony-forming GMDs were sorted by fluorescence-activated cell sorting (FACS). To further get pure cultures, a subsequent enrichment culture and a streaking purification procedure were conducted on marine R2A medium. Eighty bacterial strains isolated by the GMD-based method were randomly selected for sequencing. These isolates belonged to Alphaproteobacteria (33%), Gammaproteobacteria (44%), Bacteroidetes (11%), Actinobacteria (5%), Firmicutes (5%), Epsilonproteobacteria (1%), and Verrucomicrobia (1%), the last two groups being usually difficult to culture. The 16S rRNA gene sequences revealed a diverse community with 91.1%-100% of the bacterial rRNAs similarities. Thirteen strains were sharing 16S rRNA gene sequence which was less than 97% similar to any other rRNA genes currently deposited in TYP16S database. Seventy isolates derived from the standard plating method fell into 4 different taxonomic groups: Alphaproteobacteria (9%), Gammaproteobacteria (81%), Bacteroidetes (7%) and Firmicutes (3%) with a 16S rRNA gene sequence similarities between 95.8%-100%, in which only 3 strains were sharing 16S rRNA gene sequence of less than 97%. The results indicated that the GMD-based method with subenrichment culture yielded more taxonomic groups and more novel microbial strains, including members of previously rarely cultured groups, when compared with the standard plating method, and that this method markedly improved the bacterial cultivability.

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

    PubMed Central

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

    2014-01-01

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

  10. 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.

  11. 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.

  12. Experimental analysis of thermal performance of flat plate and evacuated tube solar collectors in stationary standard and daily conditions

    SciTech Connect

    Zambolin, E.; Del Col, D. [Dipartimento di Fisica Tecnica, Universita degli Studi di Padova, Via Venezia 1, 35131 Padova (Italy)

    2010-08-15

    New comparative tests on two different types of solar collectors are presented in this paper. A standard glazed flat plate collector and an evacuated tube collector are installed in parallel and tested at the same working conditions; the evacuated collector is a direct flow through type with external compound parabolic concentrator (CPC) reflectors. Efficiency in steady-state and quasi-dynamic conditions is measured following the standard and it is compared with the input/output curves measured for the whole day. The first purpose of the present work is the comparison of results in steady-state and quasi-dynamic test methods both for flat plate and evacuated tube collectors. Besides this, the objective is to characterize and to compare the daily energy performance of these two types of collectors. An effective mean for describing and analyzing the daily performance is the so called input/output diagram, in which the collected solar energy is plotted against the daily incident solar radiation. Test runs have been performed in several conditions to reproduce different conventional uses (hot water, space heating, solar cooling). Results are also presented in terms of daily efficiency versus daily average reduced temperature difference: this allows to represent the comparative characteristics of the two collectors when operating under variable conditions, especially with wide range of incidence angles. (author)

  13. Angular shear plate

    DOEpatents

    Ruda, Mitchell C. (Tucson, AZ); Greynolds, Alan W. (Tucson, AZ); Stuhlinger, Tilman W. (Tucson, AZ)

    2009-07-14

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

  14. 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).

  15. Enhanced sensitivity to dielectric function and thickness of absorbing thin films by combining total internal reflection ellipsometry with standard ellipsometry and reflectometry

    NASA Astrophysics Data System (ADS)

    Lizana, A.; Foldyna, M.; Stchakovsky, M.; Georges, B.; Nicolas, D.; Garcia-Caurel, E.

    2013-03-01

    High sensitivity of spectroscopic ellipsometry and reflectometry for the characterization of thin films can strongly decrease when layers, typically metals, absorb a significant fraction of the light. In this paper, we propose a solution to overcome this drawback using total internal reflection ellipsometry (TIRE) and exciting a surface longitudinal wave: a plasmon-polariton. As in the attenuated total reflectance technique, TIRE exploits a minimum in the intensity of reflected transversal magnetic (TM) polarized light and enhances the sensitivity of standard methods to thicknesses of absorbing films. Samples under study were stacks of three films, ZnO?:?Al/Ag/ZnO?:?Al, deposited on glass substrates. The thickness of the silver layer varied from sample to sample. We performed measurements with a UV-visible phase-modulated ellipsometer, an IR Mueller ellipsometer and a UV-NIR reflectometer. We used the variance-covariance formalism to evaluate the sensitivity of the ellipsometric data to different parameters of the optical model. Results have shown that using TIRE doubled the sensitivity to the silver layer thickness when compared with the standard ellipsometry. Moreover, the thickness of the ZnO?:?Al layer below the silver layer can be reliably quantified, unlike for the fit of the standard ellipsometry data, which is limited by the absorption of the silver layer.

  16. One Inch Thermal Bubble Jet Printhead With Laser Structured Integrated Polyimide Nozzle Plate

    Microsoft Academic Search

    Timo Lindemann; Heidi Ashauer; Ying Yu; Duccio Spartaco Sassano; Roland Zengerle; Peter Koltay

    2007-01-01

    This paper reports on a novel 1\\/3 and 1-in thermal bubble jet printhead with integrated nozzle plate. The printheads are made by a combination of a standard printhead substrate with a new three-dimensional (3-D) structured polyimide nozzle plate avoiding a three-layer assembly known from other commercial printheads. The 50-mum- (respectively, 75-mum)-thick nozzle plate contains the fluidic channels and 208 (respectively,

  17. 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.

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

    Microsoft Academic Search

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

    1975-01-01

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

  19. 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.

  20. Casting/mold thermal contact heat transfer during solidification of Al-Cu-Si alloy (LM 21) plates in thick and thin molds

    NASA Astrophysics Data System (ADS)

    Prabhu, K. Narayan; Chowdary, Bheemappa; Venkataraman, N.

    2005-10-01

    Heat flow at the casting/mold interface was assessed and studied during solidification of Al-Cu-Si (LM 21) alloy in preheated cast iron molds of two different thicknesses, coated with graphite and alumina based dressings. The casting and the mold were instrumented with thermocouples connected to a computer controlled temperature data acquisition system. The thermal history at nodal locations in the mold and casting obtained during experimentation was used to estimate the heat flux by solving the one-dimensional inverse heat conduction problem. The cooling rate and solidification time were measured using the computer-aided cooling curve analysis data. The estimated heat flux transients showed a peak due to the formation of a stable solid shell, which has a higher thermal conductivity compared with the liquid metal in contact with the mold wall prior to the occurrence of the peak. The high values of heat flux transients obtained with thin molds were attributed to mold distortion due to thermal stresses. For thin molds, assumption of Newtonian heating yielded reliable interfacial heat transfer coefficients as compared with one-dimensional inverse modeling. The time of occurrence of peak heat flux increased with a decrease in the mold wall thickness and increase in the casting thickness.

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

    Microsoft Academic Search

    S. M. Johnson

    1976-01-01

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

  2. 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.

  3. 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.

  4. Plate TectonicsPlate Tectonics Plate TectonicsPlate Tectonics

    E-print Network

    Siebel, Wolfgang

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

  5. Measuring Metal Thickness With an Electric Probe

    NASA Technical Reports Server (NTRS)

    Shumka, A.

    1986-01-01

    Thickness of metal parts measured from one side with aid of Kelvin probe. Method developed for measuring thickness of end plate on sealed metal bellows from outside. Suitable for thicknesses of few thousandth's of inch (few hundred micrometers). Method also used to determine thickness of metal coatings applied by sputtering, electroplating, and flame spraying.

  6. The quadratic MITC plate and MITC shell elements in plate bending

    Microsoft Academic Search

    Phill-Seung Lee; Klaus-Jürgen Bathe

    2010-01-01

    The analysis of plates can be achieved using the quadratic MITC plate or MITC shell elements. The plate elements have a strong mathematical basis and have been shown to be optimal in their convergence behavior, theoretically and numerically. The shell elements have not (yet) been analyzed mathematically in depth for their rates of convergence, with the plate\\/shell thickness varying, but

  7. Plate motion

    SciTech Connect

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

    1991-01-01

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

  8. Martian plate tectonics

    Microsoft Academic Search

    N. H. Sleep

    1994-01-01

    The northern lowlands of Mars have been produced by plate tectonics. Preexisting old thick highland crust was subducted, while seafloor spreading produced thin lowland crust during late Noachian and Early Hesperian time. In the preferred reconstruction, a breakup margin extended north of Cimmeria Terra between Daedalia Planum and Isidis Planitia where the highland-lowland transition is relatively simple. South dipping subduction

  9. Plate Tectonics

    NSDL National Science Digital Library

    Mrs. Rohlfing

    2011-02-03

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

  10. Violin plate modes.

    PubMed

    Gough, Colin

    2015-01-01

    As the first step toward developing a generic model for the acoustically radiating vibrational modes of the violin and related instruments, the modes of both freely supported and edge-constrained top and back plates have been investigated as functions of shape, arching height, elastic anisotropy, the f-holes and associated island area, thickness graduations, and the additional boundary constraints of the ribs, soundpost, and bass-bar present in the assembled instrument. Comsol shell structure finite element software has been used as a quasi-experimental tool, with physical and geometric properties varied smoothly, often over several orders of magnitude, allowing the development of the plate modes to be followed continuously from those of an initially square plate to those of doubly-arched, guitar-shaped, orthotropic plates and their dependence on all the above factors. PMID:25618046

  11. 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.

  12. Plate Tectonics

    NSDL National Science Digital Library

    Smoothstone

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

  13. Plate Tectonics

    NSDL National Science Digital Library

    Mrs. Walls

    2011-01-30

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

  14. Adherent protective coatings plated on magnesium-lithium alloy

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Zinc is plated on a magnesium-lithium alloy by using a modification of the standard zinc-plate immersion bath. Further protection is given the alloy by applying a light plating of copper on the zinc plating. Other metals are plated on the copper by using conventional plating baths.

  15. Thick Toenails

    MedlinePLUS

    ... also be seen in individuals with nail fungus (onychomycosis), psoriasis, and hypothyroidism. Those who have problems with the thickness of their toenails should consult a foot and ankle surgeon for proper diagnosis and treatment. and or or and or or, ...

  16. Tectonic Plates and Plate Boundaries

    NSDL National Science Digital Library

    2005-12-17

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

  17. Standardizing

    NSDL National Science Digital Library

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

  18. 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.

  19. Evaluation of ISO 10272:2006 standard versus alternative enrichment and plating combinations for enumeration and detection of Campylobacter in chicken meat.

    PubMed

    Habib, Ihab; Uyttendaele, Mieke; De Zutter, Lieven

    2011-09-01

    In the present study, we evaluate the recommended ISO 10272:2006 versus alternative procedures for Campylobacter enumeration and enrichment in naturally contaminated chicken meat samples (n = 49). Three enrichment media were evaluated; Bolton broth, Preston broth and CampyFood broth(®) (bioMérieux SA, Marcy l'Etoile, France). In addition, three selective plating agars were compared; modified charcoal cefoperazone deoxycholate agar (mCCDA), CampyFood agar(®) (CFA; bioMérieux SA) and Brilliance CampyCount agar(®) (BCC; Oxoid, Basingstoke, England). Direct plating on CFA provided the highest number of Campylobacter positive samples (17/49); however this was not statistically different (P > 0.05) from numbers of positive samples recovered by direct plating on mCCDA (15/49) or BCC agars (14/49). Also, there was no significant difference between Campylobacter counts on the three compared media (P > 0.05). The coloured colonies of Campylobacter on CFA and BCC were easier to record and count than those on mCCDA. Enrichment of chicken meat samples in Bolton broth for 48 h and subsequent plating on CFA provided significantly higher (P < 0.05) Campylobacter detection compared to the other broth-agar combinations. Enrichment in Preston broth for 24 h followed by plating on mCCDA gave a higher number of positive samples (20/49) than 48 h enrichment in Bolton broth and plating on mCCDA (15/49). Enrichment in Bolton broth for 48 h followed by plating on CFA recovered 35% of samples below the limit for quantifications (<10 CFU/g, n = 34), as identified by direct plating on mCCDA. Compared to the current ISO method, some alternative combinations of enrichment and agar media could provide significantly better detection and enumeration of Campylobacter in chicken meat. PMID:21645809

  20. Plate Tectonics

    NSDL National Science Digital Library

    2006-01-01

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

  1. Plate Tectonics

    NSDL National Science Digital Library

    Timothy Heaton

    This site contains 25 questions on the topic of plate tectonics, which covers the development of the theory, crustal movements, geologic features associated with tectonics, and plate boundaries (convergent, divergent, transform). This is part of the Principles of Earth Science course at the University of South Dakota. Users submit their answers and are provided immediate verification.

  2. Statistical tests of additional plate boundaries from plate motion inversions

    Microsoft Academic Search

    Seth Stein; R. G. Gordon

    1984-01-01

    The application of the F-ratio test, a standard statistical technique, to the results of relative plate motion inversions has been investigated. The method tests whether the improvement in fit of the model to the data resulting from the addition of another plate to the model is greater than that expected purely by chance. This approach appears to be useful in

  3. Earth science: The slippery base of a tectonic plate

    NASA Astrophysics Data System (ADS)

    Rychert, Catherine A.

    2015-02-01

    High-resolution imaging of the base of the Pacific plate as it descends beneath New Zealand discloses a 10-kilometre-thick channel that decouples the plate from underlying upper mantle. See Letter p.85

  4. Plate motions: fundamentals

    E-print Network

    Déverchère, Jacques

    lithospheric plates" · Plate tectonics = a kinematic theory ­ Rigid plates (no intraplate deformation") · Convergent = subductions ("trenches") · Strike-slip = transform faults · Plate tectonics describesPlate motions: fundamentals · Assume a pie-shaped wedge plate B, rotating around E (=rotation pole

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

    SciTech Connect

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

    1995-11-10

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

  6. Plate Motions

    NSDL National Science Digital Library

    Jeffrey Nunn

    To prepare for this exercise students read the Chapter on plate tectonics in their text book. In class, they are given a color isochron map of the sea floor. They are given 4 tasks: Answer basic questions about the timing and rate of opening of the N. and S. Atlantic; Determine what has happened to the oceanic crust that is created on the eastern side of the East Pacific Rise; Determine what type of plate boundary existed on the western edge of the N. America plate before the San Andreas Fault and when this transition occurred; and Reconstruct the motion of the plates over the last 40 Ma assuming that the surface area of the Earth has not changed.

  7. Plate Tectonics

    NSDL National Science Digital Library

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

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

    Microsoft Academic Search

    S. Johnson

    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.

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

    PubMed

    Mehrkash, Milad; Azhari, Mojtaba; Mirdamadi, Hamid Reza

    2014-01-01

    The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates. PMID:23714123

  10. 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...

  11. 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.

  12. 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.

  13. Buckling Analysis of Rectangular Plates With Holes

    NASA Technical Reports Server (NTRS)

    Nemeth, M. P.

    1987-01-01

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

  14. THE STABILIZED MITC PLATE BENDING ELEMENTS

    Microsoft Academic Search

    Mikko Lyly; Rolf Stenberg

    Three new families of nite element methods for the Reissner-Mindlin plate bending model are described. The methods are based on a combination of the stabilized formulation presented in (25) and the MITC reduction technique (6). The families use identical basis functions for the deflection and the rotation. Optimal order of convergence, independent of the plate thickness, is proved. The theoretical

  15. Mechanical properties and microstructure of gas tungsten arc welded magnesium AZ91D plates

    Microsoft Academic Search

    A. Munitz; C. Cotler; A. Stern; G. Kohn

    2001-01-01

    Gas tungsten arc (GTA) welds were performed on 4-mm thick plates, machined from as-cast magnesium AZ91D ingots. The microstructure and defect formation was investigated by optical and scanning electron microscopy. Mechanical properties were determined by standard tensile tests on small-scale specimens. A wide heat affected zone (HAZ) (>3 mm) was created adjacent to the fusion line that consisted of two

  16. Assumed strain distributions for a finite strip plate bending element using Mindlin-Reissner plate theory

    NASA Technical Reports Server (NTRS)

    Chulya, Abhisak; Mullen, Robert L.

    1989-01-01

    A linear finite strip plate element based on Mindlin-Reissner plate theory is developed. The analysis is suitable for both thin and thick plates. In the formulation, new transverse shear strains are introduced and assumed constant in each two-node linear strip. The element stiffness matrix is explicitly formulated for efficient computation and computer implementation. Numerical results showing the efficiency and predictive capability of the element for the analysis of plates are presented for different support and loading conditions and a wide range of thicknesses. No sign of shear locking is observed with the newly developed element.

  17. Musical Plates

    NSDL National Science Digital Library

    2007-12-12

    This on-line project is part of the Center for Improved Engineering and Science Education (CIESE) program. As they complete this series of lessons, students will use real-time data to solve a problem, study the correlation between earthquakes and tectonic plates, and determine whether or not there is a relationship between volcanoes and plate boundaries. Musical Plates has four Core Activities that will teach students how to access and interpret real-time earthquake and volcano data and to how use the information to solve a real-world problem. Each of the core activities is designed to be used in a 45-minute class period. This unit also has three enrichment lessons and a final project lesson that can also be used for assessment.

  18. 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.

  19. 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.

  20. Musical Plates: A Study of Plate Tectonics

    NSDL National Science Digital Library

    2007-01-01

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

  1. Boron-loaded photographic plates as detectors of slow neutrons

    Microsoft Academic Search

    A R Baker

    1954-01-01

    The variations with position in the plate of the emulsion thickness and of the number of slow neutrons recorded per unit area have been determined for a 10 in. × 8 in. × 100 ? boron-loaded plate that had been irradiated uniformly with slow neutrons. The measurements were consistent with a constant concentration of boron throughout the plate and upper

  2. Analysis of tongue and groove joints for thick laminatesq Karel Matous, George J. Dvorak*

    E-print Network

    Matous, Karel

    &G) joint for joining thick quasi-isotropic laminated plates to metal or laminate adherends. As shown in Fig of a homogenized thick composite laminate to steel plate. The quasi-isotropic laminate is made of glass fabric rights reserved. Keywords: Adhesive joints 1. Introduction Adhesive joining of thick composite laminates

  3. An analytical study on the free vibration of smart circular thin FGM plate based on classical plate theory

    Microsoft Academic Search

    Farzad Ebrahimi; Abbas Rastgo

    2008-01-01

    Analytical investigation of the free vibration behavior of thin circular functionally graded (FG) plates integrated with two uniformly distributed actuator layers made of piezoelectric (PZT4) material based on the classical plate theory (CPT) is presented in this paper. The material properties of the FG substrate plate are assumed to be graded in the thickness direction according to the power-law distribution

  4. Tectonic Plates and Plate Boundaries

    NSDL National Science Digital Library

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

  5. 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.

  6. Asymmetric flexural vibration and thermoelastic stability of FGM circular plates using finite element method

    Microsoft Academic Search

    T. Prakash; M. Ganapathi

    2006-01-01

    Here, asymmetric free vibration characteristics and thermoelastic stability of functionally graded circular plates are investigated using finite element procedure. A three-noded shear flexible plate element based on the field-consistency principle is used. Temperature field is assumed to be a uniform distribution over the plate surface and varied in thickness direction only. Material properties are graded in the thickness direction according

  7. FINITE ELEMENT ANALYSIS FOR THERMAL BUCKLING BEHAVIOUR IN FUNCTIONALLY GRADED PLATES WITH CUT-OUTS

    Microsoft Academic Search

    D. Saji; S. C. Pradhan

    Finite element formulation for the thermal buckling of moderately thick rectangular functionally graded material (FGM) plates is developed. This is based on the first order shear deformation theory (FSDT). One dimensional heat conduction equation is employed to represent the temperature distribution across thickness of the FGM plate. Material properties of the plate are considered to be function of temperature. It

  8. Standard practice for evaluation of disbonding of bimetallic stainless alloy/steel plate for use in high-pressure, high-temperature refinery hydrogen service

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This practice covers a procedure for the evaluation of disbonding of bimetallic stainless alloy/steel plate for use in refinery high-pressure/high-temperature (HP/HT) gaseous hydrogen service. It includes procedures to (1) produce suitable laboratory test specimens, (2) obtain hydrogen charging conditions in the laboratory that are similar to those found in refinery HP/HT hydrogen gas service for evaluation of bimetallic specimens exposed to these environments, and (3) perform analysis of the test data. The purpose of this practice is to allow for comparison of data among test laboratories on the resistance of bimetallic stainless alloy/steels to hydrogen-induced disbonding (HID). 1.2 This practice applies primarily to bimetallic products fabricated by weld overlay of stainless alloy onto a steel substrate. Most of the information developed using this practice has been obtained for such materials. The procedures described herein, may also be appropriate for evaluation of hot roll bonded, explosive bonded...

  9. Characterizing Plate Boundaries

    NSDL National Science Digital Library

    Bill Hirt

    To prepare for this exercise students read about the processes that operate at plate boundaries and how they are related to the distinct patterns of seismicity, volcanism, surface elevations (e.g., ridges versus trenches), and seafloor ages characteristic of different boundary types. During the week the assignment is available online, students have access to: (1) an index map that locates three boundaries they are to study; and (2) four maps from Sawyer's Discovering Plate Boundaries website that provide the data mentioned above. Student tasks are to: (1) document patterns in each type of data along the three targeted boundaries; and (2) use these observations in conjunction with their understandings of the processes that operate along different types of boundaries to decide whether each of the targeted sites is most likely to be a divergent, convergent, or shear boundary. This activity gives students practice in map reading, interpreting the likely tectonic setting of a boundary by pulling together constraints from several types of data, and collaborating with their classmates in an online environment. The activity also provides a foundation for understanding a wide range of phenomena that are discussed later in the semester in the context of plate tectonic processes. Teaching Tips Adaptations that allow this activity to be successful in an online environment Sawyer's Discovering Plate Boundaries is a jigsaw exercise in which students collaboratively develop an empirical classification of plate boundaries by first studying an individual data set (e.g., seismicity) and then working as part of a multidisciplinary team to develop a composite classification for the boundaries of a single plate using several types of data. In order for the classification to be truly empirical, students are not introduced to the "traditional" classification of plate boundaries till the end of the exercise. In adapting this assignment to the online environment I have: (1) asked students to prepare by becoming familiar with the standard classification of plate boundaries and the processes that operate at them; (2) limited their work to three targeted boundaries of different types; and (3) provided guidance about which features to look for in the each data set. I have found that these modifications help online students, who often work alone "on their own schedules", to avoid getting "lost" and frustrated with the assignment and to compensate for the lack of collaborative input they would receive in a classroom setting. Elements of this activity that are most effective The success of this exercise is really seems to depend on how well a student follows the directions. If a student learns about the geologic differences among plate boundaries, makes careful observations, and thoughtfully compares his or her observations to the expected patterns he or she typically does quite well based on answers to the follow-up questions. If, on the other hand, a student simply looks up the types of the targeted boundaries on a map and then attempts to "back out" the observations that he or she thinks should fit, the result is often inconsistency and a poor score on the questions. (I can often tell which approach a student is taking based on the queries they post to the discussion board, but rarely seem to be able to get those who are trying to work backwards through the assignment to change direction.) Recommendations for other faculty adapting this activity to their own course: To date my experience developing an engaging online exercise to help students learn the principles of plate tectonics has only been partly successful. I think that having such an exercise is critical, however, because this topic provides the framework for so much of what we learn in the geosciences. Based on my efforts to adapt elements of Discovering Plate Boundaries to an online environment I would offer three recommendations. (1) Provide examples. Confronted with an unfamiliar map students are sometimes confused when asked to decide if seafloor age, for example, is uniform or variable

  10. Statistical tests of additional plate boundaries from plate motion inversions

    NASA Technical Reports Server (NTRS)

    Stein, S.; Gordon, R. G.

    1984-01-01

    The application of the F-ratio test, a standard statistical technique, to the results of relative plate motion inversions has been investigated. The method tests whether the improvement in fit of the model to the data resulting from the addition of another plate to the model is greater than that expected purely by chance. This approach appears to be useful in determining whether additional plate boundaries are justified. Previous results have been confirmed favoring separate North American and South American plates with a boundary located beween 30 N and the equator. Using Chase's global relative motion data, it is shown that in addition to separate West African and Somalian plates, separate West Indian and Australian plates, with a best-fitting boundary between 70 E and 90 E, can be resolved. These results are generally consistent with the observation that the Indian plate's internal deformation extends somewhat westward of the Ninetyeast Ridge. The relative motion pole is similar to Minster and Jordan's and predicts the NW-SE compression observed in earthquake mechanisms near the Ninetyeast Ridge.

  11. Voltage-current characteristics of a pin-plate system with different plate configurations

    NASA Astrophysics Data System (ADS)

    Feng, Zhuangbo; Long, Zhengwei

    2013-03-01

    In this paper, the voltage-current (V-I) characteristics of a pin-plate system with four types of collection plate configurations are studied experimentally. The collection plates consider a single metal plate, a metal plate with a fly ash cake layer, a metal plate with a clean filter media and a metal plate with a dirty filter media. The results show that the clean filter media has no obvious effect on the V-I characteristics. But the dirty filter media reduces the current density because of its high resistance. The thick fly ash cake layer increase current density because of the anti-corona effect but the increment is not very obvious.

  12. Learning Assessment #1 - Plate Tectonics

    NSDL National Science Digital Library

    Michelle Speta

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

  13. Plate Tectonics II: Plates, plate boundaries, and driving forces

    NSDL National Science Digital Library

    Anne Egger

    2003-03-18

    The distribution of earthquakes and volcanoes around the world confirmed the theory of plate tectonics first proposed by Wegener. These phenomena also help categorize plate boundaries into three different types: convergent, divergent, and transform.

  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. A preliminary study of bending stiffness alteration in shape changing nitinol plates for fracture fixation.

    PubMed

    Olender, Gavin; Pfeifer, Ronny; Müller, Christian W; Gösling, Thomas; Barcikowski, Stephan; Hurschler, Christof

    2011-05-01

    Nitinol is a promising biomaterial based on its remarkable shape changing capacity, biocompatibility, and resilient mechanical properties. Until now, very limited applications have been tested for the use of Nitinol plates for fracture fixation in orthopaedics. Newly designed fracture-fixation plates are tested by four-point bending to examine a change in equivalent bending stiffness before and after shape transformation. The goal of stiffness alterable bone plates is to optimize the healing process during osteosynthesis in situ that is customized in time of onset, percent change as well as being performed non-invasively for the patient. The equivalent bending stiffness in plates of varying thicknesses changed before and after shape transformation in the range of 24-73% (p values <0.05 for all tests). Tests on a Nitinol plate of 3.0 mm increased in stiffness from 0.81 to 0.98 Nm² (corresponding standard deviation 0.08 and 0.05) and shared a good correlation to results from numerical calculation. The stiffness of the tested fracture-fixation plates can be altered in a consistent matter that would be predicted by determining the change of the cross-sectional area moment of inertia. PMID:21286815

  16. Asymptotic analysis of contact problems between an elastic material and thin-rigid plates

    Microsoft Academic Search

    Mustapha El Jarroudi

    2010-01-01

    We consider an elastic material in contact with a three-dimensional rigid plate of varying thickness. We suppose that a perfect adhesion occurs along thin zones disposed in a self-similar way on the interface between the two materials. We suppose that the elasticity coefficients in the plate depend on its thickness and tend to infinity as this thickness tends to zero.

  17. 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...

  18. 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...

  19. 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...

  20. 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.

  1. Tectonic Plates and Plate Boundaries (WMS)

    NSDL National Science Digital Library

    Eric Sokolowsky

    2004-06-14

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

  2. A theoretical analysis of FGM thin plates based on physical neutral surface

    Microsoft Academic Search

    Da-Guang Zhang; You-He Zhou

    2008-01-01

    This paper presents a theoretical analysis to the FGM (functionally graded materials) thin plates based on the physical neutral surface. Under the assumption of changeable parameters such as the Young’s modulus E and the mass density ? along the thickness of the plate, the physical neutral surface of a FGM plate is determined by the theory of thin plate when

  3. Rozhen Observatory wide-field plate archives

    NASA Astrophysics Data System (ADS)

    Tsvetkova, K.; Tsvetkov, M.

    2013-01-01

    This paper provides an overview of the wide-field (>10) plate archives at disposal in the Institute of Astronomy and National Astronomical Observatory Rozhen of the Bulgarian Academy of Sciences. The plates with total number 10093 are obtained in the period November 1978 - February 1998 with the 2 m RCC telescope and 50/70/172 cm Schmidt telescope. The available plate catalogues are upgraded with new information, as well as with link to the digitized logbooks (in JPEG file format). The digitization with high quality EPSON flatbed scanners of the available 2 m RCC telescope plates (with low resolution in JPEG, and with high resolution in standardized FITS file format) is accomplished. The digitization of the available 50/70/172 cm Schmidt telescope plates is running. The low resolution images of the scanned Rozhen plates are included in the Wide-Field Plate Database (http://wfpdb.org) and accessible online.

  4. 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.

  5. The Biggest Plates on Earth: Plate Tectonics

    NSDL National Science Digital Library

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

  6. Earth's Decelerating Tectonic Plates

    Microsoft Academic Search

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

    2008-01-01

    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

  7. Flat Plate Cascades at Supersonic Speed

    NASA Technical Reports Server (NTRS)

    El Badrawy, Rashad M

    1956-01-01

    A brief review of exact two-dimensional supersonic flow theory and Ackeret's linearized theory are first presented. The lift and drag coefficients of a cascade of flat plates are calculated exactly and compared to those obtained using the linearized theory. The forces on the cascade are determined for unsteady inlet flow. The flat plate cascade theory is extended to compute the efficiency of a supersonic propeller with friction and finite blade thickness.

  8. 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.

  9. Orthogonal femoral plating

    PubMed Central

    Auston, D. A.; Werner, F. W.; Simpson, R. B.

    2015-01-01

    Objectives This study tests the biomechanical properties of adjacent locked plate constructs in a femur model using Sawbones. Previous studies have described biomechanical behaviour related to inter-device distances. We hypothesise that a smaller lateral inter-plate distance will result in a biomechanically stronger construct, and that addition of an anterior plate will increase the overall strength of the construct. Methods Sawbones were plated laterally with two large-fragment locking compression plates with inter-plate distances of 10 mm or 1 mm. Small-fragment locking compression plates of 7-hole, 9-hole, and 11-hole sizes were placed anteriorly to span the inter-plate distance. Four-point bend loading was applied, and the moment required to displace the constructs by 10 mm was recorded. Results We found that a 1 mm inter-plate distance supported greater moments than a 10 mm distance in constructs with only lateral plates. Moments supported after the addition of a 9- or 11-hole anterior plate were greater for both 10 mm and 1 mm inter-plate distance, with the 11-hole anterior plate supporting a greater moment than a 9-hole plate. Femurs with a 7-hole anterior plate fractured regardless of lateral inter-plate distance size. Conclusion This suggests that the optimal plate configuration is to minimise lateral inter-plate distance and protect it with an anterior plate longer than seven holes. Cite this article: Bone Joint Res 2015;4:23–8. PMID:25715873

  10. Caribbean plate tectonics

    NSDL National Science Digital Library

    Sting

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

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

    NSDL National Science Digital Library

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

  12. 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...

  13. 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.

  14. Closed-form solution for free vibration of piezoelectric coupled annular plates using Levinson plate theory

    NASA Astrophysics Data System (ADS)

    Hosseini Hashemi, Sh.; Es'haghi, M.; Karimi, M.

    2010-04-01

    Free vibration analysis of annular moderately thick plates integrated with piezoelectric layers is investigated in this study for different combinations of soft simply supported, hard simply supported and clamped boundary conditions at the inner and outer edges of the annular plate on the basis of the Levinson plate theory (LPT). The distribution of electric potential along the thickness direction in the piezoelectric layer is assumed as a sinusoidal function so that the Maxwell static electricity equation is approximately satisfied. The differential equations of motion are solved analytically for various boundary conditions of the plate. In this study the closed-form solution for characteristic equations, displacement components of the plate and electric potential are derived for the first time in the literature. To demonstrate the accuracy of the present solution, comparison studies is first carried out with the available data in the literature and then natural frequencies of the piezoelectric coupled annular plate are presented for different thickness-radius ratios, inner-outer radius ratios, thickness of piezoelectric, material of piezoelectric and boundary conditions. Present analytical model provides design reference for piezoelectric material application, such as sensors, actuators and ultrasonic motors.

  15. 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.

  16. Network formalism for modeling functionally gradient piezoelectric plates and stacks and simulations of RAINBOW ceramic actuators.

    PubMed

    Ballato, J; Schwartz, R; Ballato, A

    2001-03-01

    A simple network representation is given for a stack of thin, homogeneous piezoelectric plates, executing a single thickness mode of motion. All plates may differ in thickness and material properties, including dielectric loss, ohmic conductivity, and viscous loss. Each plate is driven by a thickness-directed electric field, and all stack elements are connected electrically in series. Functionally gradient single plates and composites are readily modeled by the network, to a desired precision, using a sequence of circuit elements representing stepwise variations in material properties and layer thicknesses. Simulations of RAINBOW (Reduced And Internally Biased Oxide Wafer) ceramics are given. PMID:11370360

  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. 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

  19. Volcano spacing and plate rigidity

    SciTech Connect

    Brink, U. (Stanford Univ., California (USA))

    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.

  20. MTR plates modeling with MAIA

    SciTech Connect

    Marelle, V.; Dubois, S.; Ripert, M.; Noirot, J. [DEN/DEC, CEA Cadarache, 13108 St Paul Lez Durance (France); Lemoine, P. [DEN/DSOE, CEA Saclay, 91191 Gif sur Yvette (France)

    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)

  1. 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.

  2. 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.

  3. 49 CFR 179.100-6 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... d = Inside diameter in inches; E = 1.0 welded joint efficiency; except for heads with seams=0.9...sufficient to bring the entire width of the longitudinal welded joint, including welds, above the bolster. [29 FR...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...representing the efficiency of welded joints, except that for seamless heads...representing the efficiency of welded joints, except that for seamless heads...representing the efficiency of welded joints, except that for seamless...

  5. 49 CFR 179.200-6 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...diameter in inches; E = 0.9 Welded joint efficiency; except E =1.0...diameter in inches; E = 0.9 Welded joint efficiency; except E =1.0...EC13NO91.034 Where: E = 0.9 Welded joint efficiency; except E...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... d = Inside diameter in inches; E = 0.9 welded joint efficiency; except E =1.0 for seamless heads...following formula: EC13NO91.036 Where: E = 0.9 welded joint efficiency; except E =1.0 for seamless...

  7. 49 CFR 179.220-6 - Thickness of plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... d = Inside diameter in inches; E = 0.9 welded joint efficiency; except E =1.0 for seamless heads...following formula: EC13NO91.036 Where: E = 0.9 welded joint efficiency; except E =1.0 for seamless...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...representing the efficiency of welded joints, except that for seamless heads...representing the efficiency of welded joints, except that for seamless heads...representing the efficiency of welded joints, except that for seamless...

  9. 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.

  10. 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...

  11. Plate Tectonics Animation

    NSDL National Science Digital Library

    2002-01-01

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

  12. Planet Earth: Plate Tectonics

    E-print Network

    Watts, A. B. "Tony"

    , ice and sediment for long periods of geological time (>105 a). · Controlled and passive (e-plate system #12;Relative plate motions on a sphere A In a three-plate system, A, B and C, if AB and BC are known then CA can be found. See GG p23-24. Euler's theorem: motion of any spherical plate can

  13. Cerebral Cortical Thickness Measurements

    Microsoft Academic Search

    M. L. J. Scott; N. A. Thacker

    2004-01-01

    The assessment of human cerebral cortical thickness (the thickness of the cortical grey matter ribbon) has massive clinical importance in the determination of pathology and in assessing the processes of \\

  14. Compression buckling response of tailored rectangular composite plates

    NASA Technical Reports Server (NTRS)

    Biggers, Sherrill B.; Srinivasan, Sundar

    1993-01-01

    Buckling resistance is often a controlling criterion in the design of structures composed of plate elements. Design concepts that lead to increased buckling loads (or strains) of these plate elements can directly lower the structural cost and/or weight by a number of means. This study quantifies the improvements that can be achieved in compression buckling loads of rectangular composite plates by using a simple stiffness-tailoring concept. The approach is to position the unidirectional lamina through the thickness and over the planform of the plate so that the buckling load is increased with no loss in in-plane stiffness or increase in weight. Finite element analyses have been used to determine the effects of tailoring on the buckling loads of plates with various boundary conditions, aspect ratios, thicknesses, and membrane stiffnesses. Increases in buckling loads (or strains) of 200 percent or more compared to the uniform plate-buckling loads are shown possible with this tailoring concept.

  15. Thermal postbuckling analysis of FGM skew plates

    Microsoft Academic Search

    T. Prakash; M. K. Singha; M. Ganapathi

    2008-01-01

    In this paper, the postbuckling behavior of functionally graded material (FGM) skew plates under thermal load is investigated based on the shear deformable finite element approach. The material is graded in the thickness direction according to a power-law distribution in terms of the volume fractions of the constituents. The Mori–Tanaka homogenization method is used to estimate the effective material properties

  16. Mapping Plate Tectonic Boundaries

    NSDL National Science Digital Library

    Michael Kerwin

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

  17. Transition conditions at the interface between floating plates Hyuck Chung

    E-print Network

    Fox, Colin

    ice thickness, mass density and Young's modulus to be constant. This model is often used to study-H to list them all here.) A similar technique is used in [3] to solve a plate-plate interaction with an open

  18. Thin shell vesicles composed of hydrophilic plate-like nanoparticles

    Microsoft Academic Search

    Anand Subramaniam; Jiandi Wan; Arvind Gopinath; Howard Stone

    2011-01-01

    Nanopowders of graphene oxide, montmorillonite and laponite spontaneously delaminate into ultrathin nanoscopic plates when dispersed in water. These plates, which are typically ˜ 1 nm thick and microns in lateral dimension, have found many uses as precursors to graphene, ceramics, layer-by-layer structures, and as structural modifiers of nanocomposites. Here we show that mechanical forces due to shear in a narrow

  19. Characterization of an ultra-thick positive photoresist for electroplating applications

    NASA Astrophysics Data System (ADS)

    Flack, Warren W.; Nguyen, Ha-Ai; Capsuto, Elliott S.

    2003-06-01

    The performance requirements for ultra-thick photoresists have increased rapidly with the dramatic growth in new lithographic applications that require electroplating processes. Two of the main applications for ultra-thick photoresists are nanotechnology (MEMS) and advanced packaging. Flipchip packaging has become widely adopted to address electrical device performance and chip form factor considerations. The growth in the nanotechnology market is driven by a wide range of products, which include accelerometers, ink jet print heads, biomedical sensors and optical switches. Electroplating levels for these applications require a photosensitive polymer material capable of coating, exposing and plating with conventional semiconductor equipment and standard ancillary process chemicals. A single coat step to achieve the final photoresist thickness is critical to minimize the number of process steps and cycle time. The sidewall profile, aspect ratio, electroplating durability and subsequent stripability are all important. This study characterized a novel positive photosensitive chemically amplified photoresist (ShinEtsu SIPR) for the use in a 65?m thick electroplating level on copper. The lithographic performance of the ultra-thick positive photoresist was optimized using a broad band, low numerical aperture, 1x stepper to control critical dimensions (CD), sidewall angles and aspect ratios. Cross sectional SEM analysis, contrast curves, process linearity, and process latitude plots were used to establish the lithographic capabilities. High aspect ratio structures were then electroplated using the optimized photoresist process to demonstrate photoresist durability and stripability. A recommended process flow is described for this photoresist and stepper.

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

    SciTech Connect

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

    2010-08-15

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

  1. Non-cyanide silver plating

    SciTech Connect

    Dini, J.W.

    1995-11-07

    Lawrence Livermore National Laboratory (LLNL) and Technic, Inc. have entered into a CRADA (Cooperative Research and Development Agreement) with the goal of providing industry with an environmentally benign alternative to the presently used silver cyanide plating process. This project has been in place for about six months and results are quite promising. The main objective, that of deposition of deposits as thick as 125 um (5 mils), has been met. Property data such as stress and hardness have been obtained and the structure of the deposit has been analyzed via metallography and x-ray diffraction. These results will be presented in this paper, along with plans for future work.

  2. Analysis and optimal design of thick composite structures with passive damping considerations

    NASA Technical Reports Server (NTRS)

    Saravanos, D. A.

    1992-01-01

    A design methodology to tailor thick composite plates for optimal static and damping performance is presented. The method is based on discrete layer composite mechanics, hence, is suitable for thick composite laminates. The design criteria include static deflections, frequency and damping constraints. Evaluations on cross-ply simply-supported plates illustrate the advantages of the methodology. Comparisons with design methods based on the classical laminate theory show significant deviations in the resultant optimal designs at higher thicknesses.

  3. 78 FR 30271 - Stainless Steel Plate in Coils From Belgium, South Africa, and Taiwan: Notice of Court Decision...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-22

    ...Steel Plate in Coils From Belgium, South Africa, and Taiwan: Notice of Court...in coils (SSPC) from Belgium, South Africa, and Taiwan with a nominal thickness...Plate in Coils from Belgium and South Africa; and Notice of...

  4. Effects of Plasma Instabilities on Tungsten Divertor Plate

    E-print Network

    Effects of Plasma Instabilities on Tungsten Divertor Plate Ahmed Hassanein Argonne National 03 SurfaceTemperature,K Time, µs 10 MJ/m2 1 ms Vaporization Thickness (µm) Tungsten Melted Thickness (µm) Ts HEIGHTS Analysis of Tungsten Target Thermal Evolution during Plasma Energy Deposition #12;1 0

  5. Nonlinear analysis of FGM plates under pressure loads using the higher-order shear deformation theories

    Microsoft Academic Search

    R. Sarfaraz Khabbaz; B. Dehghan Manshadi; A. Abedian

    2009-01-01

    In this study, the energy concept along with the first- and third-order shear deformation theories (FSDT and TSDT) are used to predict the large deflection and through the thickness stress of FGM plates. These responses are studied and discussed as a function of plate thickness and the order “n” of a power law function which is considered for the through

  6. Dynamic stability analysis of FGM plates by the moving least squares differential quadrature method

    Microsoft Academic Search

    Wu Lanhe; Wang Hongjun; Wang Daobin

    2007-01-01

    The present paper investigates the dynamic stability of thick functionally graded material plates subjected to aero-thermo-mechanical loads, using a novel numerical solution technique, the moving least squares differential quadrature method. Temperature field is assumed to be a uniform distribution over the plate plane, and varied in the thickness direction only. Material properties are assumed to be temperature dependent and graded

  7. Nonlinear free flexural vibrations of functionally graded rectangular and skew plates under thermal environments

    Microsoft Academic Search

    N. Sundararajan; T. Prakash; M. Ganapathi

    2005-01-01

    The nonlinear formulation developed based on von Karman's assumptions is employed to study the free vibration characteristics of functionally graded material (FGM) plates subjected to thermal environment. Temperature field is assumed to be a uniform distribution over the plate surface and varied in the thickness direction. The material is assumed to be temperature dependent and graded in the thickness direction

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

    NASA Technical Reports Server (NTRS)

    Biricikoglu, V.

    1971-01-01

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

  9. Ultrasonic metal sheet thickness measurement without prior wave speed calibration

    NASA Astrophysics Data System (ADS)

    Dixon, S.; Petcher, P. A.; Fan, Y.; Maisey, D.; Nickolds, P.

    2013-11-01

    Conventional ultrasonic mensuration of sample thickness from one side only requires the bulk wave reverberation time and a calibration speed. This speed changes with temperature, stress, and microstructure, limiting thickness measurement accuracy. Often, only one side of a sample is accessible, making in situ calibration impossible. Non-contact ultrasound can generate multiple shear horizontal guided wave modes on one side of a metal plate. Measuring propagation times of each mode at different transducer separations, allows sheet thickness to be calculated to better than 1% accuracy for sheets of at least 1.5 mm thickness, without any calibration.

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

    SciTech Connect

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

    1995-11-01

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

  11. Macular Thickness and Amblyopia

    PubMed Central

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

    2014-01-01

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

  12. Lead Thickness Measurements

    SciTech Connect

    Rucinski, R.; /Fermilab

    1998-02-16

    The preshower lead thickness applied to the outside of D-Zero's superconducting solenoid vacuum shell was measured at the time of application. This engineering documents those thickness measurements. The lead was ordered in sheets 0.09375-inch and 0.0625-inch thick. The tolerance on thickness was specified to be +/- 0.003-inch. The sheets all were within that thickness tolerance. The nomenclature for each sheet was designated 1T, 1B, 2T, 2B where the numeral designates it's location in the wrap and 'T' or 'B' is short for 'top' or 'bottom' half of the solenoid. Micrometer measurements were taken at six locations around the perimeter of each sheet. The width,length, and weight of each piece was then measured. Using an assumed pure lead density of 0.40974 lb/in{sup 3}, an average sheet thickness was calculated and compared to the perimeter thickness measurements. In every case, the calculated average thickness was a few mils thinner than the perimeter measurements. The ratio was constant, 0.98. This discrepancy is likely due to the assumed pure lead density. It is not felt that the perimeter is thicker than the center regions. The data suggests that the physical thickness of the sheets is uniform to +/- 0.0015-inch.

  13. Create Your Plate

    MedlinePLUS

    ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal Planning ... Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with ...

  14. Plate Tectonics: Further Evidence

    NSDL National Science Digital Library

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

  15. 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.

  16. External Resource: Plate Tectonics

    NSDL National Science Digital Library

    1900-01-01

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

  17. The PLATES Project

    NSDL National Science Digital Library

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

  18. Growth Plate Injuries

    MedlinePLUS

    ... may be negatively affected. How Are Growth Plate Fractures Diagnosed? A child who has persistent pain, or ... 1999. Used with the author’s permission. Type I: Fracture Through the Growth Plate The epiphysis is completely ...

  19. Ultrasonic measurement of condensate film thickness.

    PubMed

    Kimball, Jeramy T; Bailey, Michael R; Hermanson, James C

    2008-10-01

    The current work describes a modified time-of-flight ultrasound signal processing technique applied to the study of a distal liquid layer with a free surface. The technique simulates multiple reflections analytically and determines the film thickness by comparison to the measured pulse echo signal. The technique is applied with 20 MHz transducers to an n-pentane film condensing on a copper plate. The technique proved capable of measuring liquid thickness from approximately 8 microm, 16 the acoustic wavelength in pentane, to greater than 5 mm. Near the lower thickness limit, echoes from the liquid/vapor interface overlap each other and the significantly larger echoes from the metal/liquid interface. PMID:19062786

  20. Postbuckling of FGM plates with piezoelectric actuators under thermo-electro-mechanical loadings

    Microsoft Academic Search

    Hui-Shen Shen

    2005-01-01

    A postbuckling analysis is presented for a simply supported, shear deformable functionally graded plate with piezoelectric actuators subjected to the combined action of mechanical, electrical and thermal loads. The temperature field considered is assumed to be of uniform distribution over the plate surface and through the plate thickness and the electric field considered only has non-zero-valued component EZ. The material

  1. Active control of FGM plates with integrated piezoelectric sensors and actuators

    Microsoft Academic Search

    X. Q. He; T. Y. Ng; S. Sivashanker; K. M. Liew

    2001-01-01

    In this paper, a finite element formulation based on the classical laminated plate theory is presented for the shape and vibration control of the functionally graded material (FGM) plates with integrated piezoelectric sensors and actuators. The properties of the FGM plates are functionally graded in the thickness direction according to a volume fraction power law distribution. A constant velocity feedback

  2. Vibration and dynamic response of functionally graded plates with piezoelectric actuators in thermal environments

    Microsoft Academic Search

    Xiao-Lin Huang; Hui-Shen Shen

    2006-01-01

    This paper deals with the nonlinear vibration and dynamic response of a functionally graded material (FGM) plate with surface-bonded piezoelectric layers in thermal environments. Heat conduction and temperature-dependent material properties are both taken into account. The temperature field considered is assumed to be a uniform distribution over the plate surface and varied in the thickness direction of the plate, and

  3. Nonlinear thermomechanical post-buckling of circular FGM plate with geometric imperfection

    Microsoft Academic Search

    Shi-Rong Li; Jing-Hua Zhang; Yong-Gang Zhao

    2007-01-01

    Nonlinear thermomechanical post-buckling of an imperfect functionally graded material (FGM) circular plate, subjected to both mechanical load and transversely non-uniform temperature rise, is presented. The material properties of FGM plates are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Based on von Kármán's plate

  4. The optimum arrangement of the plates in a multi-layered shield

    Microsoft Academic Search

    G. Ben-Dor; A. Dubinsky; T. Elperin

    2000-01-01

    A normal impact of a three-dimensional rigid conical impactor penetrating into a layered shield is studied using a simplified model for an impactor–shield interaction. The shield consists of adjacent plates manufactured from one of two possible materials, and the total thickness of the plates manufactured from every material is given. It is found that advancing any plate inside a shield

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

    Microsoft Academic Search

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

    1991-01-01

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

  6. Plate Tectonics: Moving Middle School Science

    NSDL National Science Digital Library

    Carolee Barber

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

  7. A generalized plane-strain theory for transversally isotropic plates

    Microsoft Academic Search

    A. Kotousov; C. H. Wang

    2003-01-01

    Summary.  ?By adopting Kane and Mindlin's assumption that the through-the-thickness extensional strain is uniform through the plate\\u000a thickness, a generalized plane-strain theory is developed for transversely isotropic plates. The three-dimensional governing\\u000a equations are successfully reduced to two coupled equations in the two-dimensional space. With the new theory, explicit solutions\\u000a of the three-dimensional stresses, especially the through-the-thickness component, around a circular hole

  8. Plate Tectonic Primer

    NSDL National Science Digital Library

    Lynn Fichter

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

  9. Earthquakes and Plate Tectonics

    NSDL National Science Digital Library

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

  10. Rotatable shear plate interferometer

    DOEpatents

    Duffus, Richard C. (Livermore, CA)

    1988-01-01

    A rotatable shear plate interferometer comprises a transparent shear plate mounted obliquely in a tubular supporting member at 45.degree. with respect to its horizontal center axis. This tubular supporting member is supported rotatably around its center axis and a collimated laser beam is made incident on the shear plate along this center axis such that defocus in different directions can be easily measured.

  11. Solderability and environmental testing of Sn-plated surfaces

    SciTech Connect

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

    1990-01-01

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

  12. Thick film hydrogen sensor

    DOEpatents

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

    1995-01-01

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

  13. 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.

  14. 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…

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

    SciTech Connect

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

    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).

  16. 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.

  17. 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.

  18. Rifting consequences of three plate separation

    NASA Astrophysics Data System (ADS)

    Sibuet, Jean-Claude; Srivastava, Shiri

    1994-04-01

    Submarine sedimentary basins parallel to the trends of passive continental margins are well explained by tensional processes between two lithospheric plates. This leaves open the enigma of many basins which strike across margins. We use examples from the North Atlantic to show that such basins may be formed during the initial rifting stage due to enhanced lithospheric thinning caused by the separation of three plates. We suggest that volcanics can be emplaced in these basins and, in the extreme case, where mantle temperature and consequently the degree of partial melting are particularly high, that basaltic flows can be thick enough to fill and hide the basins.

  19. NSTX Upgrade Armor Plate Backing Plate

    E-print Network

    Princeton Plasma Physics Laboratory

    .1 Finite Element Software and OPERA Electromagnetic program. 3.) Opera electromagnetic program and results backing plate calculation 2.) Build and evaluate a Finite Element Model for The Armor Eddy Current

  20. Mantle Convection Moving Plates

    NSDL National Science Digital Library

    This demonstration models the manner in which the convection currents in the mantle of the Earth cause movement of the plates. Convection currents in the mantle were thought, for many years, to be solely responsible for plate tectonic movements, with the movement taking rocks down at destructive margins and new rocks forming when plates spread. It is now thought likely that there are three possible driving mechanisms for plate tectonics. In addition to movement of mantle convection currents as shown in this demonstration, scientists also consider the mass of the subducted plate (the sinking slab) at the subduction zone dragging the surface part of the plate across the surface and the new plate material sliding off the higher oceanic ridges at constructive margins.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

    Böttcher, Andreas; Peschel, Astrid; Johannsmann, Diethelm

    2015-03-01

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

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

    PubMed

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

    2015-04-01

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

  4. Thermal diffusivity of nonflat plates using the flash method

    SciTech Connect

    Salazar, Agustin; Fuente, Raquel; Apinaniz, Estibaliz; Mendioroz, Arantza [Departamento de Fisica Aplicada I, Escuela Tecnica Superior de Ingenieria, Universidad del Pais Vasco, Alameda Urquijo s/n, 48013 Bilbao (Spain)

    2011-01-15

    The flash method is the standard technique to measure the thermal diffusivity of solid samples. It consists of heating the front surface of an opaque sample by a brief light pulse and detecting the temperature evolution at its rear surface. The thermal diffusivity is obtained by measuring the time corresponding to the half maximum of the temperature rise, which only depends on the sample thickness and thermal diffusivity through a simple formula. Up to now, the flash method has been restricted to flat samples. In this work, we extend the flash method to measure the thermal diffusivity of nonflat samples. In particular, we focus on plates with cylindrical and spherical shapes. The theoretical model indicates that the same expression for flat samples can also be applied to cylindrical and spherical plates, except for extremely curved samples. Accordingly, a curvature limit for the application of the expression for flat samples is established. Flash measurements on lead foils of cylindrical shape confirm the validity of the model.

  5. Improvement of protective coating on Nd-Fe-B magnet by pulse nickel plating

    Microsoft Academic Search

    C. W. Cheng; F. T. Cheng; H. C. Man

    1998-01-01

    Sintered Nd-Fe-B magnets were coated by pulse nickel plating at different plating conditions. Optimal pulse plating condition was established (average current density=1 A\\/dm2, peak current density=6 A\\/dm2 with Ton:Toff=1:2). In order to make a comparison, magnets with similar nickel coating thickness plated by dc were also prepared. The corrosion resistance of the coated magnets was evaluated by (i) Normal Salt

  6. Improvement of protective coating on Nd–Fe–B magnet by pulse nickel plating

    Microsoft Academic Search

    C. W. Cheng; F. T. Cheng; H. C. Man

    1998-01-01

    Sintered Nd–Fe–B magnets were coated by pulse nickel plating at different plating conditions. Optimal pulse plating condition was established (average current density=1 A\\/dm2, peak current density=6 A\\/dm2 with Ton:Toff=1:2). In order to make a comparison, magnets with similar nickel coating thickness plated by dc were also prepared. The corrosion resistance of the coated magnets was evaluated by (i) Normal Salt

  7. A fracture mechanics analysis for delamination growth during impact on composite plates

    NASA Technical Reports Server (NTRS)

    Bostaph, G. M.; Elber, W.

    1983-01-01

    A fracture mechanics analysis has been developed that describes the progress of delamination damage in composite plates struck by a hard spherical object. The analysis is based on large deflection plate mechanics for circular isotropic plates wherein multiple axisymmetric delaminations grow. Test data show that the analysis predicts the influence of plate thickness, support conditions, and matrix toughness on the onset and propagation of delamination.

  8. 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...

  9. Physics of thick polymers

    E-print Network

    D. Marenduzzo; A. Flammini; A. Trovato; J. R. Banavar; A. Maritan

    2005-08-19

    We present the results of analytic calculations and numerical simulations of the behaviour of a new class of chain molecules which we call thick polymers. The concept of the thickness of such a polymer, viewed as a tube, is encapsulated by a special three body interaction and impacts on the behaviour both locally and non-locally. When thick polymers undergo compaction due to an attractive self-interaction, we find a new type of phase transition between a compact phase and a swollen phase at zero temperature on increasing the thickness. In the vicinity of this transition, short tubes form space filling helices and sheets as observed in protein native state structures. Upon increasing the chain length, or the number of chains, we numerically find a crossover from secondary structure motifs to a quite distinct class of structures akin to the semi-crystalline phase of polymers or amyloid fibers in polypeptides.

  10. Elastic theory of unconstrained non-Euclidean plates

    NASA Astrophysics Data System (ADS)

    Efrati, E.; Sharon, E.; Kupferman, R.

    2009-04-01

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

  11. 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.

  12. United States crustal thickness

    NASA Technical Reports Server (NTRS)

    Allenby, R. J.; Schnetzler, C. C.

    1983-01-01

    The thickness of the crust, the thickness of the basal (intermediate or lower) crustal layer, and the average velocity at the top of the mantle have been mapped using all available deep-penetrating seismic-refraction profiles in the conterminous United States and surrounding border areas. These profiles are indexed to their literature data sources. The more significant long wavelength anomalies on the three maps are briefly discussed and analyzed. An attempt to use Bouguer gravity to validate mantle structure was inconclusive.

  13. Thick frequency selective surfaces

    Microsoft Academic Search

    D. B. Webb; E. Michielssen; R. Mittra

    1992-01-01

    As an additional means of controlling bandwidth, the use of periodic screens in free space with thick metallization was investigated for single-square loop and double-concentric-square loop elements. These loops elements were chosen because the passbands of such screens, with tight lattice spacing, display a remarkable insensitivity to incident polarization and angle of incidence. The effect of thick metallization on passband

  14. Teaching Box: Evidence for Plate Tectonics

    NSDL National Science Digital Library

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

  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. 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.

  17. 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.

  18. Understanding Plate Motions

    NSDL National Science Digital Library

    This interactive site uses illustrations and photographs along with text to explain the movement of tectonic plates and the result of this movement on the surface of the Earth. There is a detailed discussion of the movement at each of the four types of plate boundaries: divergent, convergent, transform, and plate boundary zones. Both lateral and vertical movements are depicted by maps and diagrams and resulting Earth structures are shown in photographs.

  19. Geology - Plate Tectonics

    NSDL National Science Digital Library

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

  20. Measurement of sediment and crustal thickness corrected RDA for 2D profiles at rifted continental margins: Applications to the Iberian, Gulf of Aden and S Angolan margins

    NASA Astrophysics Data System (ADS)

    Cowie, Leanne; Kusznir, Nick

    2014-05-01

    Subsidence analysis of sedimentary basins and rifted continental margins requires a correction for the anomalous uplift or subsidence arising from mantle dynamic topography. Whilst different global model predictions of mantle dynamic topography may give a broadly similar pattern at long wavelengths, they differ substantially in the predicted amplitude and at shorter wavelengths. As a consequence the accuracy of predicted mantle dynamic topography is not sufficiently good to provide corrections for subsidence analysis. Measurements of present day anomalous subsidence, which we attribute to mantle dynamic topography, have been made for three rifted continental margins; offshore Iberia, the Gulf of Aden and southern Angola. We determine residual depth anomaly (RDA), corrected for sediment loading and crustal thickness variation for 2D profiles running from unequivocal oceanic crust across the continental ocean boundary onto thinned continental crust. Residual depth anomalies (RDA), corrected for sediment loading using flexural backstripping and decompaction, have been calculated by comparing observed and age predicted oceanic bathymetries at these margins. Age predicted bathymetric anomalies have been calculated using the thermal plate model predictions from Crosby & McKenzie (2009). Non-zero sediment corrected RDAs may result from anomalous oceanic crustal thickness with respect to the global average or from anomalous uplift or subsidence. Gravity anomaly inversion incorporating a lithosphere thermal gravity anomaly correction and sediment thickness from 2D seismic reflection data has been used to determine Moho depth, calibrated using seismic refraction, and oceanic crustal basement thickness. Crustal basement thicknesses derived from gravity inversion together with Airy isostasy have been used to correct for variations of crustal thickness from a standard oceanic thickness of 7km. The 2D profiles of RDA corrected for both sediment loading and non-standard crustal thickness provide a measurement of anomalous uplift or subsidence which we attribute to mantle dynamic topography. We compare our sediment and crustal thickness corrected RDA analysis results with published predictions of mantle dynamic topography from global models.

  1. 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.

  2. 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.

  3. Composite plates impact damage - An atlas

    NASA Astrophysics Data System (ADS)

    Finn, Scott R.; Springer, George S.

    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.

  4. Surface preparation and plating

    SciTech Connect

    Dini, J.W.; Waldrop, F.B.; Reno, R.W.

    1982-10-06

    This chapter covers electroplating and electroless nickel plating since coatings of this type play an important role in diamond turning technology. Items to be discussed include preparation of substrates prior to coating, plating defects such as pits and nodules and their influence on optics, the influence of stress in coatings, plating details for copper, gold, silver, and electroless nickel, and the importance of additives and their influence on grain size and structure of deposits. Some comments are made on future challenges that could be presented to the plating community to further improve the quality of coatings applied for diamond turning purposes. 60 references, 8 figures, 9 tables.

  5. Plates on the Move

    NSDL National Science Digital Library

    This fun Web article is part of OLogy, where kids can collect virtual trading cards and create projects with them. Here, they learn about the Earth's outer shell and its constant movement. It begins with an overview that explains tectonic plates. There is an animation that shows recent earthquakes and their relationship to plate boundaries. Students can click to explore 12 individual volcanoes, mountains, hotspots, and earthquakes. For each of the geological formations or events, they will see a map that shows how the plates are moving, an animation about plate interaction, stats, and a story about that particular formation or event.

  6. Acceleration of metal plates

    NASA Astrophysics Data System (ADS)

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

    1989-08-01

    High-explosive charges were used to accelerate stainless steel plates to velocities of 6 to 7 km/s. A two-stage system was 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.

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

    NASA Astrophysics Data System (ADS)

    Chen, Xing-Le; Lei, Yin-Zhao

    2015-03-01

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

  8. 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

  9. Spreading continents kick-started plate tectonics

    NASA Astrophysics Data System (ADS)

    Rey, Patrice F.; Coltice, Nicolas; Flament, Nicolas

    2014-09-01

    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.

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

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

    NASA Technical Reports Server (NTRS)

    1976-01-01

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

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

    NASA Technical Reports Server (NTRS)

    1976-01-01

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

  20. 40 CFR 426.40 - Applicability; description of the plate glass manufacturing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  1. 40 CFR 426.40 - Applicability; description of the plate glass manufacturing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  2. 40 CFR 426.40 - Applicability; description of the plate glass manufacturing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  3. 40 CFR 426.40 - Applicability; description of the plate glass manufacturing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  5. 76 FR 60531 - National Institute of Justice Interview Room Recording Systems and License Plate Readers Workshop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-29

    ...1569] National Institute of Justice Interview Room Recording Systems and License Plate...Institute of Justice. ACTION: Notice of the Interview Room Recording Systems and License Plate...development of NIJ performance standards for Interview Room Recording Systems and License...

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

    E-print Network

    Xu, Zhiguang

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

  7. 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

  8. Solderability of environmentally exposed Sn-plated surfaces

    SciTech Connect

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

    1990-01-01

    Solderability of Class II environmentally exposed Ni-Sn plated Cu substrates was evaluated with 60Sn-40Pb solder. Tin thickness were 10, 50, and 150 {mu}in. The 10 {mu}in. plating gave the smallest solder meniscus rise. A general decrease in contact angle, or increase in wettability, was observed with increasing Sn plating. The environmental exposures retarded the wetting rate and increased the time to maximum wetting, particularly with only 10 {mu}in. of Sn. Although the solderability of the 50 and 150 {mu}in. surfaces were not significantly affected by the test conditions, an intermediate plating thickness of 100 {mu}in. is preferred for processing flexibility. 13 refs., 6 figs., 1 tab.

  9. Improved compression buckling for rectangular composite plates by stiffness tailoring

    NASA Technical Reports Server (NTRS)

    Biggers, Sherrill B.; Srinivasan, Sundar

    1991-01-01

    Buckling resistance is often a controlling criterion in the design of structural elements. Design concepts that lead to increased buckling loads (or strains) can directly lower the structural cost and/or weight by a number of means. This study quantifies the improvements that can be achieved in compression buckling loads of rectangular composite plates by using a simple stiffness tailoring concept. The approach is to position the unidirectional lamina through the thickness and over the planform of the plate so that the buckling load is increased with no loss in in-plane stiffness or increase in weight. Finite element analyses have been used to determine the effects of tailoring on the buckling load of plates with various boundary conditions, aspect ratios, thicknesses, and membrane stiffnesses. Increases in buckling loads (or strains) of nearly 200 percent over the uniform plate buckling loads are shown possible with this tailoring concept.

  10. New acoustic plate modes with quasi-linear polarizations.

    PubMed

    Anisimkin, Vladimir

    2012-10-01

    New acoustic plate modes (APMs) with quasishear- vertical (QSV) and quasi-shear-horizontal (QSH) polarizations are found numerically in piezoelectric, nonpiezoelectric, and isotropic plates with free faces. Experimental verification of the modes is accomplished for ST,X-quartz plate, as an example. Similar to the modes with quasi-longitudinal displacement reported recently, the new counterparts exist when their velocities v(APM) are close to the velocities v(BAW) of the relevant bulk waves, the value of the dispersion slope dv(APM)/d(h/?) is low enough (dv(APM)/d(h/?) ~100 m/s, where h is thickness and ? is wavelength), and allowable plate thickness h/? form a regular succession. All modes with quasi-linear polarization originate from generalized Lamb modes transformed at the aforementioned conditions. PMID:23143587

  11. Monitoring production target thickness

    SciTech Connect

    Oothoudt, M.A.

    1993-01-01

    Pion and muon production targets at the Clinton P. Anderson Meson Physics Facility consist of rotating graphite wheels. The previous target thickness monitoring Procedure scanned the target across a reduced intensity beam to determine beam center. The fractional loss in current across the centered target gave a measure of target thickness. This procedure, however, required interruption of beam delivery to experiments and frequently indicated a different fractional loss than at normal beam currents. The new monitoring Procedure compares integrated ups and downs toroid current monitor readings. The current monitors are read once per minute and the integral of readings are logged once per eight-hour shift. Changes in the upstream to downstream fractional difference provide a nonintrusive continuous measurement of target thickness under nominal operational conditions. Target scans are now done only when new targets are installed or when unexplained changes in the current monitor data are observed.

  12. Monitoring production target thickness

    SciTech Connect

    Oothoudt, M.A.

    1993-06-01

    Pion and muon production targets at the Clinton P. Anderson Meson Physics Facility consist of rotating graphite wheels. The previous target thickness monitoring Procedure scanned the target across a reduced intensity beam to determine beam center. The fractional loss in current across the centered target gave a measure of target thickness. This procedure, however, required interruption of beam delivery to experiments and frequently indicated a different fractional loss than at normal beam currents. The new monitoring Procedure compares integrated ups and downs toroid current monitor readings. The current monitors are read once per minute and the integral of readings are logged once per eight-hour shift. Changes in the upstream to downstream fractional difference provide a nonintrusive continuous measurement of target thickness under nominal operational conditions. Target scans are now done only when new targets are installed or when unexplained changes in the current monitor data are observed.

  13. 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,...

  14. 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,...

  15. 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.

  16. Mapping Plate Boundaries

    NSDL National Science Digital Library

    Rurik Johnson

    2009-11-12

    This in-class exercise, profiled on the Starting Point website, is intended to have the students discover plate boundaries based on the uneven geographic occurrence of geologic hazards. The website details the learning goals, teaching notes and materials, and context for this activity. It offers an extensive list of links to additional resources and materials for lecture on geologic hazards and plate tectonics.

  17. How Do Plates Move?

    NSDL National Science Digital Library

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

  18. 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.

  19. The Moving Plates

    NSDL National Science Digital Library

    This lesson focuses on relative versus absolute velocity. Students can use a program (must be connected to the internet) to calculate the different types of velocities for different points along plate boundaries. A very brief description of the earth's plates is given, with links to additional information and images. Includes discussion questions.

  20. Review of plate tectonics

    Microsoft Academic Search

    Kevin Burke; A. M. C. Sengor

    1979-01-01

    This article reviews advances in plate tectonics in a variety of different plate environments. Mapping using multibeam echo sounding and deep-water photographic and geophysical packages and understanding of mid-oceanic ridges, the subsidence of sea floor as oceanic lithosphere cools with age, the nature and behavior of oceanic and continental transform faults, and advances in knowledge of subduction zones including the

  1. Impact failure mechanisms in alumina tiles on finite thickness support and the effect of confinement

    Microsoft Academic Search

    Dov Sherman

    2000-01-01

    The quasi-static and the dynamic damage mechanisms in alumina tiles backed by finite thickness support plates and subjected to a variety of boundary conditions were investigated. The tile\\/plate assemblies were impacted by NATO 0.3cal. armor piercing (AP) rounds with hardened and sharpened steel core. The alumina tile samples were 50×50mm2 area, their thicknesses ranging from 3 to 12mm. The backup

  2. Influence of filter thickness on PESA calibration

    NASA Astrophysics Data System (ADS)

    Trompetter, W. J.; Davy, P.; Barry, B.; Kennedy, J.

    2014-08-01

    Elemental analysis of air particulate matter collected on Teflon filters using ion beam analysis (IBA) allows simultaneous analysis of the hydrogen content. Hydrogen is determined by a method known as particle elastic scattering analysis (PESA). The hydrogen concentration in the air particulate matter samples is determined by comparing the ratio of the hydrogen peak yield to the yields from standards of known hydrogen composition. The study presented in this paper shows that this process can be inaccurate if the calibration standards used are of different thicknesses compared to the air pollution samples. A series of experiments were undertaken to investigate the effect of sample and standard thickness on the determination of hydrogen concentrations. It was found that the filter thickness and the distribution of the air particulate matter within the filter significantly affected the yield of the hydrogen peak in the PESA spectra. Therefore, it is important to consider the effect of thickness and the distribution of the hydrogen in both the calibration standards and the sample filters for PESA analysis.

  3. General properties of the Anisimkin Jr. plate modes.

    PubMed

    Anisimkin, Vladimir I

    2010-09-01

    Acoustic plate modes of different orders n, having equal velocities v(n) close to that of the longitudinal BAW v(L), are numerically studied in crystals of different symmetries. Three families of the modes with v(n) ? v(L), each at relevant plate thickness h/? = (h/?)n, are found (h is the thickness, ? is the wavelength): the generalized Lamb mode with comparable longitudinal u1, shear-horizontal u2, and shear-vertical u3 displacements, the Anisimkin Jr. (AN) mode with u1 > u2 and u3, and u1 ? constant ? 0 at any depth, and the quasilongitudinal (QL) mode with u1 > u2, and u3, but u1 ? constant over the plate thickness. Existence of the families does not depend on anisotropy or piezoelectric properties of the plate, but on the closeness of the mode velocity v(n) to the BAW velocity v(L), the value of the dispersion slope dv(n)/d(h/?) at v(n) = v(L) and h/? = (h/?)n, and the proximity of the plate thickness (h/?)n supporting the mode, to the thickness (h/?)R providing transverse BAW resonance between plate faces. The Lamb modes approach v(n) = v(L) at irregular (h/?)n far from resonance (h/?)R and at large dv(n)/d(h/?) ~10(3) m/s. The two other modes are characterized by lower dispersion dv(n)/d(h/?) ? 10(3) m/s and regular (h/?)n close to the resonance (h/?)R. Because both modes have small vertical displacement on plate faces and propagate almost entirely within the crystals, they are attractive for liquid sensing. PMID:20875992

  4. Fashion Plate Collection

    NSDL National Science Digital Library

    There are fashion plates, and then there are the exquisite fashion plates that constitute the University of Washington Libraries digitized collection. The plates were first collected by long-time home economics professor Blanche Payne, who taught at the University from 1927 to 1966. The plates come from leading French, American, and British fashion journals of the 19th and early 20th century and they document many stylistic periods, such as the Empire, Romantic, Victorian, and Edwardian. Visitors will want to start by reading an essay on the collection, and then they should feel welcome to browse the collection of over 400 plates at their leisure, or to browse the collection by subject. One fascinating aspect of the site is an extended excerpt from the 1913 book "Dame fashion" which comments on the history and transformation of various fashions during the 19th century.

  5. Thermophoresis of Graphene Plates

    NASA Astrophysics Data System (ADS)

    Bubenchikov, A. M.; Bubenchikov, M. A.; Potekaev, A. I.; Maslov, A. S.; Ovcharenko, V. V.; Usenko, O. V.

    2014-11-01

    Thermophoresis of graphene plates in an air medium is discussed within the framework of a molecular-kinetic approach. Its rate is found to be independent of the plate area and the aspect ratio of a rectangular graphene. It does depend on the plate orientation in space, which is controlled by the principle of least resistance. The dependence is expressed via a geometrical parameter ?, whose limiting values within the variation interval are found to be 0.46 and 0.65. A solution of the Euler problem on the Brownian rotation of a plate around its center of mass as a result of collisions of molecules in the temperature gradient field allowed us to obtain for the graphene plates a statistical average of ? =0.5. This value turned out to be the same as the one for spherical nanoparticles, for which rotations are irrelevant.

  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. Research on the Bistablity of FGM Laminate Plates

    Microsoft Academic Search

    Zheng Zhang; Yumei Bao; Hongxia Sun

    2010-01-01

    Bi-stable functionally graded material (FGM) laminated plates are studied in this paper. Considering the bistablity, the isotropic and anisotropic composite laminate plates are analyzed. The numerical results of different FGM under different loading are compared with homogeneous materials by using continuous graded thickness integration rule of shell element. Then, the bistablity of different rotation angle layered composites including [-45°\\/45°], [0°\\/90°],

  8. Optical vortices produced with a nonspiral phase plate

    NASA Astrophysics Data System (ADS)

    Kim, Guang-Hoon; Jeon, Jin-Ho; Ko, Kwang-Hoon; Moon, Hee-Jong; Lee, Jai-Hyung; Chang, Joon-Sung

    1997-11-01

    We present simple methods to produce optical vortices on the axis of beam propagation with nonspiral phase plates. We show that a phase plate that provides linear phase retardation on one half of a laser beam produces optical vortices, which is demonstrated experimentally by use of a thickness-varying glass platelet. We also demonstrate and explain that mixed dislocations of a bent edge dislocation transform into a pair of vortices with opposing topological charges.

  9. Thermal cycle reliability of solder joints to alternate plating finishes

    Microsoft Academic Search

    R. Wayne Johnson; Vicky Wang; Michael Palmer

    1999-01-01

    Studies immersion gold over electroless nickel, immersion gold over electroless palladium, immersion gold over electroless palladium over electroless nickel, immersion gold over immersion silver and immersion silver. In the palladium finishes, two palladium thicknesses were evaluated: 10-12?in. and 18-20?in. Multiple plating chemistry suppliers provided plated test vehicles. HASL and OSP test vehicles were included as control samples. In total, 14

  10. PLATE TECTONICS USING GIS Understanding plate tectonics using real

    E-print Network

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

  11. Improved finite strip Mindlin plate bending element using assumed shear strain distributions

    NASA Technical Reports Server (NTRS)

    Chulya, Abhisak; Thompson, Robert L.

    1988-01-01

    A linear finite strip plate element based on Mindlin/Reissner plate theory is developed. The analysis is suitable for both thin and thick plates. In the formulation new transverse shear strains are introduced and assumed constant in each two-code linear strip. The element stiffness matrix is explicitly formulated for efficient computation and computer implementation. Numerical results showing the efficiency and predictive capability of the element for the analysis of plates are presented for different support and loading conditions and a wide range of thicknesses. No sign of shear locking phenomenon was observed with the newly developed element.

  12. Compton Thick AGN

    NASA Astrophysics Data System (ADS)

    Levenson, N. A.

    2014-07-01

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

  13. 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.

  14. Finite element approximation of free vibration of folded plates

    Microsoft Academic Search

    Erwin Hernández; Luis Hervella-Nieto

    2009-01-01

    In this paper a finite element approximation of the free vibration of folded plates is studied. Naghdi model, including bending, shear and membrane terms for the plate, is considered. Quadrilateral low order MITC (Mixed Interpolation Tensorial Component) elements are used for the bending and shear effect, coupled with standard quadratic elements enriched with a drilling degree of freedom for the

  15. 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.

  16. Tree-thickness and caterpillar-thickness under girth constraints

    E-print Network

    West, Douglas B.

    Tree-thickness and caterpillar-thickness under girth constraints Qi Liu Douglas B. West Abstract We study extremal problems for decomposing a connected n-vertex graph G into trees or into caterpillars. The least size of such a decomposition is the tree thickness T(G) or caterpillar thickness C(G). If G has

  17. 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

  18. Static analysis of functionally graded plates using third-order shear deformation theory and a meshless method

    Microsoft Academic Search

    A. J. M. Ferreira; R. C. Batra; C. M. C. Roque; L. F. Qian; P. A. L. S. Martins

    2005-01-01

    The collocation multiquadric radial basis functions are used to analyze static deformations of a simply supported functionally graded plate modeled by a third-order shear deformation theory. The plate material is made of two isotropic constituents with their volume fractions varying only in the thickness direction. The macroscopic response of the plate is taken to be isotropic and the effective properties

  19. Plate Tectonics Jigsaw

    NSDL National Science Digital Library

    Anne Egger

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

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

    NASA Technical Reports Server (NTRS)

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

    1942-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1942-01-01

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

  2. 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.

  3. 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.

  4. Three-dimensional exact solution for the vibration of functionally graded rectangular plates

    NASA Astrophysics Data System (ADS)

    Vel, Senthil S.; Batra, R. C.

    2004-05-01

    A three-dimensional exact solution is presented for free and forced vibrations of simply supported functionally graded rectangular plates. Suitable displacement functions that identically satisfy boundary conditions are used to reduce equations governing steady state vibrations of a plate to a set of coupled ordinary differential equations, which are then solved by employing the power series method. The exact solution is valid for thick and thin plates, and for arbitrary variation of material properties in the thickness direction. Results are presented for two-constituent metal-ceramic functionally graded rectangular plates that have a power-law through-the-thickness variation of the volume fractions of the constituents. The effective material properties at a point are estimated by either the Mori-Tanaka or the self-consistent schemes. Exact natural frequencies, displacements and stresses are used to assess the accuracy of the classical plate theory, the first order shear deformation theory and a third order shear deformation theory for functionally graded plates. Parametric studies are performed for varying ceramic volume fractions, volume fraction profiles and length-to-thickness ratios. Results are also computed for a functionally graded plate that has a varying microstructure in the thickness direction using a combination of the Mori-Tanaka and the self-consistent methods. Forced vibrations of a plate with a sinusoidal spatial variation of the pressure applied on its top surface are scrutinized.

  5. Mountains and Moving Plates

    NSDL National Science Digital Library

    These are the lecture notes for a class on plate tectonics and mountain building which is taught at the University of Wisconsin-Madison. The course describes the connections between the earth's tectonic plates, earthquakes, and its many mountain ranges. Topics include basic geography, the structure of the earth's interior, the relationships between the seismic cycle, volcanism, and plate movements, erosion of mountains, and mass wasting. Links are provided to additional resources, including aerial photos of geologic features, an interactive map of geology and topography of the United States, and a glossary.

  6. Plate Tectonics at Work

    NSDL National Science Digital Library

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

  7. Nonlinearity Parameter Measurement for Polymer Plates Using Focused Ultrasound

    NASA Astrophysics Data System (ADS)

    Saito, Shigemi

    2008-06-01

    To select an appropriate material for acoustic window available for B/A imaging, the acoustic property including B/A has been measured for 1 mm thick polymer plates with a focusing system. Observing the second harmonic components contained in the sound transmitted through the polymer plate which is put, together with a sound reflector set at the back, within the focal region of 18.6 MHz focused ultrasound yields an extraordinary B/A value as large as 26.6, for example, in polystyrene. Taking into account the phase advances of the second harmonic due to velocity dispersion in polymer plate and multiple reflections at the gap between the plate and reflector, however, the B/A in polystyrene is corrected to 11.4. In a similar manner, the B/A values are obtained for other polymer plates.

  8. 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.

  9. 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.

  10. Optimizing material properties of composite plates for sound transmission problem

    NASA Astrophysics Data System (ADS)

    Tsai, Yu-Ting; Pawar, S. J.; Huang, Jin H.

    2015-01-01

    To calculate the specific transmission loss (TL) of a composite plate, the conjugate gradient optimization method is utilized to estimate and optimize material properties of the composite plate in this study. For an n-layer composite plate, a nonlinear dynamic stiffness matrix based on the thick plate theory is formulated. To avoid huge computational efforts due to the combination of different composite material plates, a transfer matrix approach is proposed to restrict the dynamic stiffness matrix of the composite plate to a 4×4 matrix. Moreover, the transfer matrix approach has also been used to simplify the complexity of the objective function gradient for the optimization method. Numerical simulations are performed to validate the present algorithm by comparing the TL of the optimal composite plate with that of the original plate. Small number of iterations required during convergence tests illustrates the efficiency of the optimization method. The results indicate that an excellent estimation for the composite plate can be obtained for the desired sound transmission.

  11. Correlations between force plate measures for assessment of balance

    Microsoft Academic Search

    Annica Karlsson; Gunilla Frykberg

    2000-01-01

    Objective. To compare different force plate measures for assessment of postural stability during normal standing. Five types of measures were analysed: (1) The standard deviation of the horizontal ground reaction force, (2) the standard deviation of the centre of pressure, (3) the mean velocity of the centre of pressure, (4) movement strategy measures, and (5) the standard deviation of the

  12. Plate Tectonics Learning Module

    NSDL National Science Digital Library

    Rita Haberlin

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

  13. myPlate (image)

    MedlinePLUS

    ... food choices. The guide encourages you to eat less and avoid oversized portions. Half your plate should be filled with fruits and vegetables. At least half of your grains should be whole grains. You also should switch ...

  14. 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)

  15. elementsair ceramic plate

    E-print Network

    many current day applications. Anything that creates waste heat (e.g. engines, computers, electronicsearth elementsair L ceramic plate Thermoelectric Module Construction for Low Temperature Gradient related carbon dioxide emissions are the largest contributors to greenhouse gasses [1]. Thermoelectric

  16. Farallon Plate Remnants

    NSDL National Science Digital Library

    NASA/Goddard Space Flight Center Scientific Visualization Studio

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

  17. 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.

  18. Flat plate solar oven

    SciTech Connect

    Parikh, M.

    1981-01-01

    The construction of an Indian Rs. 186 (US $20.33) flat-plate solar oven is described. Detailed drawings are provided and relevant information on cooking times and temperature for different foods is given.

  19. Growth Plate Fractures

    MedlinePLUS

    ... Harris system and is described here. Type I Fractures These fractures break through the bone at the ... and completely disrupting the growth plate. Type II Fractures These fractures break through part of the bone ...

  20. 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.

  1. Influence of cortical bone thickness on the ultrasound velocity

    PubMed Central

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

    2012-01-01

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

  2. 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.

  3. Plate Tectonics: An Introduction

    NSDL National Science Digital Library

    In the early 1900s, most geologists thought that Earth's appearance, including the arrangement of the continents, had changed little since its formation. This video segment describes the impact the theory of plate tectonics has had on our understanding of Earth's geological history, and provides a brief overview of what is currently known about the Earth's tectonic plates and their motions. The segment is two minutes twenty-one seconds in length. A background essay and list of discussion questions are also provided.

  4. Fabrication of a micro-hole array on metal foil by nanosecond pulsed laser beam machining using a cover plate

    NASA Astrophysics Data System (ADS)

    Ha, Kyoung Ho; Lee, Se Won; Kim, Janggil; Jee, Won Young; Chu, Chong Nam

    2015-02-01

    A novel laser beam machining (LBM) method is proposed to achieve higher precision and better quality beyond the limits of a commercialized nanosecond pulsed laser system. The use of a cover plate is found to be effective for the precision machining of a thin metal foil at micro scale. For verifying the capability of cover plate laser beam machining (c-LBM) technology, a 30 by 30 array of micro-holes was fabricated on 8?µm-thick stainless steel 304 (STS) foil. As a result, thermal deformation and cracks were significantly reduced in comparison with the results using LBM without a cover plate. The standard deviation of the inscribed and circumscribed circle of the holes with a diameter of 12?µm was reduced to 33% and 81%, respectively and the average roundness improved by 77%. Moreover, the smallest diameter obtainable by c-LBM in the given equipment was found to be 6.9?µm, which was 60% less than the minimum size hole by LBM without a cover plate.

  5. 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.

  6. 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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

    Xu, Ling; Nitsche, Monika

    2015-03-01

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

  9. Effectiveness of nickel plating in inhibiting atmospheric corrosion of copper alloy contacts

    SciTech Connect

    Ernest, T.; Sorensen, R.; Guilinger, T.

    1997-12-31

    A series of tests was run to determine the effect of Ni plating thickness on connector contact resistance. Copper coupons were plated with an electrolytic nickel strike followed by electroless nickel to produce Ni layers of 10, 20, 55 and 100 {micro}in. The coupons were then exposed to a simulated industrial environment. Pore corrosion was observed after the exposure, which correlated with Ni thickness. In a second series of tests, beryllium-copper four-tine contacts with 50 {micro}in of gold plate over electrolytic nickel strike/electroless-nickel plates of varying thickness were exposed the same corrosive environment. Contact resistance of mated pairs was monitored over a two-month period. The degradation in contact resistance correlated with the Ni thickness used in the connectors.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  11. Final report on APMP regional key comparison APMP.L-K6: Calibration of ball plate and hole plate

    NASA Astrophysics Data System (ADS)

    Takatsuji, Toshiyuki; Eom, Taebong; Tonmueanwai, Anusorn; Yin, Ruimin; van der Walt, Floris; Gao, Sitian; Thu, Bui Quoc; Singhal, R. P.; Howick, Eleanor; Doytchinov, Kostadin; Valente de Oliveira, José Carlos; Lassila, Antti; O'Donnell, Jim; Balsamo, Alessandro

    2014-01-01

    The results of the APMP key comparisons on ball plate and hole plate (APMP.L-K6.2007) are reported. Both transfer standards were provided by NMIJ, Japan. The ball plate standard is 532 mm by 532 mm in nominal dimension and 25 spheres are embedded. Thirteen National Metrology Institutes (8 from APMP, 5 from other Regional Metrology Organizations) participated in the ball plate measurement comparison. The hole plate standard is 550 mm by 550 mm in nominal dimension and there are 44 cylindrical holes in it. Nine National Metrology Institutes (5 from APMP, 4 from other Regional Metrology Organizations) participated in the hole plate measurement comparison. The comparison started in May 2006 and finished in October 2008. The participants used different measurement techniques which were used for their routine calibration services. For determining the key comparison reference values, a two-dimensional coordinates-based analysis was performed. The measurement results on the ball plate show good agreement in ten out of thirteen participants. In contrast, those on the hole plate are in agreement for five out of nine participants. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. Coating thickness and elastic modulus measurement using ultrasonic bulk wave resonance

    NASA Astrophysics Data System (ADS)

    Dixon, S.; Lanyon, B.; Rowlands, G.

    2006-04-01

    Measurement of the resonant through thickness ultrasonic modes of a homogeneous plate using a fast Fourier transform of the temporal data can be used to calculate plate thickness very accurately. We describe an extension of this principle to two-layer systems, examining a thin coating on a substrate of known properties. The resonant behavior of these systems is predicted and we explain how this approach is used to measure coating thickness and elastic modulus. Noncontact electromagnetic acoustic transducers are used for ultrasonic measurement, as they do not significantly affect the resonant response of the system, unlike alternative contact transducers.

  13. An Introduction to Plate Tectonics

    NSDL National Science Digital Library

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

  14. Caribbean plate interactions

    SciTech Connect

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

    1993-02-01

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

  15. 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.

  16. 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.

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

    SciTech Connect

    Ichinomiya, Osamu; Maruyama, Koichi; Sekine, Kouji [Hokkaido Inst. of Tech., Sapporo (Japan). Dept. of Mechanical engineering

    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.

  18. Mechanical behavior of functionally graded material plates under transverse load—Part I: Analysis

    Microsoft Academic Search

    Shyang-Ho Chi; Yen-Ling Chung

    2006-01-01

    An elastic, rectangular, and simply supported, functionally graded material (FGM) plate of medium thickness subjected to transverse loading has been investigated. The Poisson’s ratios of the FGM plates are assumed to be constant, but their Young’s moduli vary continuously throughout the thickness direction according to the volume fraction of constituents defined by power-law, sigmoid, or exponential function. Based on the

  19. Polar Plate Theory for Orthogonal Anisotropy

    NASA Technical Reports Server (NTRS)

    Bailey, Michelle D.; Bower, Mark V.

    2000-01-01

    Laminated fiber-reinforced (or filamentary) composites are used today for their high strength-to-weight and stiffness-to-weight ratios. However, because of the anisotropic behavior of composites, determining the response on a macroscopic scale is challenging. This is particularly evident in the evaluation of the governing differential equations of a circular disk with the fibers of the lamina oriented with rectilinear orthogonality. This includes any situation involving a composite plate of circular geometry in which out-of-plane displacements due to load are desired, such as fastener pull through loading of a composite plate. Current analysis techniques use numerical methods with rectilinear coordinate systems to solve problems with circular geometry. These analyses over predict plate stiffness by 20% and underpredict failure by 70%. Consequently, there is a need to transform classical composite plate theory to a polar coordinate system. In order to better analyze structures with circular geometries the classical composite plate equations are transformed into the plate equations for a rectilinearly anisotropic composite in polar coordinates. A composite plate is typically a laminate of fibers in rectilinear directions. Subsequent to the lay-tip the necessary geometry is cut out of a rectangular plate. In a similar manner, the derivation of the plate equation starts with the fundamental definitions of strain, displacement and curvature and incorporates the material property angular dependence into the equilibrium equations for a differential polar element. In the transformed state, the stiffness coefficients are no longer constant, adding to the complexity of the governing differential equations. This paper discusses the new derivation and evaluation of the plate equations for a circular composite disk with orthogonal rectilinear anisotropy. The resultant new three partial differential equations, which describe the circular anisotropic plate, can be used to evaluate out-of-plane displacements for given load conditions in design of composite Structures. Without the formation of these unique plate equations, design of such structures is not a precise engineering accomplishment due to the lack of precise design tools. Such structures are over designed to compensate and costly tests need to be performed after production to validate safety. Though impossible to present the mathematical solution within the limits of this paper, the application of the newly derived plate equation in its orthotropic form for a balanced symmetric laminate compared favorably with test results and surpassed the results of standard numerical methods. Within the limitations of the problem foundation the predictive model provides a mechanism for establishing out-of-plane deflection levels for a circular composite plate. Future work in this area should include incorporating the circular composite plate equations in Finite Element Models. The new anisotropic polar plate equations call be utilized as a design tool so that the design more accurately meets the requirements, thus taking full advantage of the weight savings of composites. These accomplishments have not previously been presented to the engineering community nor ever proposed to the IAF. Should the proposed paper be accepted for presentation, attendance is assured.

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

    PubMed

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

    2015-02-01

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

  1. An automatic system for measurement of retardation of wave plates based on phase-shifted method

    Microsoft Academic Search

    Zhishan Gao; Ming Yan

    2005-01-01

    A practical system is described to measure the retardation of wave plates with phase-shifted method. The tested wave plate is put in and the original angle between the axis of it and the analyzer is random, not 45 degree. For the measurement is made rapidly and automatically, a standard wave plate act as a compensator, the stepping motor is used

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

    EPA Science Inventory

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

  3. Measurement of Thin Oil Film Thickness Using Ultrasonic Technique

    NASA Astrophysics Data System (ADS)

    Takeuchi, Akitoshi; Terada, Seiichi; Toda, So

    An application of ultrasonic technique is attempted for the purpose of measuring thin oil film thickness between two surfaces. The amplitude of the wave reflected from the boundary is vary depending on film thickness, because the ultrasonic wave emitted to the interface between two surfaces does multiple reflection and interference in oil film. Quantitative measurement of oil film thickness then can be possible. For instance, it is possible to measure the submicron film thickness which exists near the point contact formed by convex glass and plate with high frequency probe. And it is confirmed that the oil film thickness estimated from the echo height agrees with the film thickness decided by the curvature of the lens or obtained by the optical interference method, even if it is 100 nm. On the other hand, the thickness of oil film between cylinder and piston ring can be easily measured by setting the small ultrasonic probe on the back of piston ring. For example, the influence of the second ring and oil ring for the behavior of an oil film formed on a top ring is able to evaluate quantitatively. As mentioned above, it is cleared that quantitative evaluation of thin film thickness is possible with investigating the echo height obtained by ultrasonic wave pulse reflection method.

  4. 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.

  5. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

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

  7. Increasing the impact fatigue strength of ring valve plates

    Microsoft Academic Search

    V. A. Pyshkin; V. A. Yakovlev; V. Yu. Kuznetsov; S. A. Abramenko

    1976-01-01

    The authors have made an investigation with the object of selecting the optimum shot treatment conditions for ring valve plates. The investigations were conducted on testpieces of grade 30Kh13 steel of length 60 mm, width 10 mm, and thickness 3 mm. These were heat treated as follows: hardening at a temperature of 10301050~ with cooling in oil, tempering at a

  8. Stress magnitude estimates from earthquakes in oceanic plate interiors

    Microsoft Academic Search

    R. Govers; M. J. R. Wortel; S. A. P. L. Cloetingh; C. A. Stein

    1992-01-01

    A method is proposed to estimate stress magnitudes in oceanic plate interiors from focal depths and focal mechanisms. Using a depth-dependent rheology, it is shown that it is possible to estimate the differential stress averaged over some reference lithospheric thickness. The resolving power of the method is investigated by evaluating the effect of uncertainties in parameters that are involved in

  9. A LOCKING-FREE LAMINATED COMPOSITE PLATE FINITE ELEMENT

    Microsoft Academic Search

    Ivan Moura Belo

    2005-01-01

    A plate finite element which is locking-free is developed usi ng strain gradient notation for the analysis of laminated composites. The element is based on a first-order s hear deformation theory and on the equivalent lamina assumption. Strains and stresses can be calculated at diffe rent points through the laminate's thickness. The paraboli c nature of the transverse shear strain

  10. An oceanic flood basalt province within the Caribbean plate

    Microsoft Academic Search

    C. W. Sinton; R. A. Duncan; M. Storey; J. Lewis; J. J. Estrada

    1998-01-01

    The thick oceanic crust of the Caribbean plate appears to be the tectonized remnant of an eastern Pacific oceanic plateau that has been inserted between North and South America. The emplacement of the plateau into its present position has resulted in the obduction and exposure of its margins, providing an opportunity to study the age relations, internal structure and compositional

  11. The symmetric turbulent wake of a flat plate

    NASA Technical Reports Server (NTRS)

    Ramaprian, B. R.; Patel, V. C.; Sastry, M. S.

    1982-01-01

    Detailed measurements of mean flow and turbulence in the developing symmetric wake of a smooth, flat plate are presented. The results are discussed in the light of previous data and theories for near and far wakes. It is shown that evolution of the upstream boundary layers into the classical asymptotic wake occurs in three quite distinct stages and takes about 350 wake momentum thicknesses.

  12. Anatomical research on the subacromial interval following implantation of clavicle hook plates.

    PubMed

    Deng, Z; Cai, L; Ping, A; Ai, Q; Wang, Y

    2014-09-01

    This article aimed to explore whether hook plate implantation significantly narrowed the subacromial space. 24 shoulder joints were implanted with clavicle hook plates. A Vernier caliper was used to measure the length and thickness of the acromion. In addition, the length and thickness of the hook of the plate were measured. The data from all measurements recorded were divided into 2 groups Group A, the length group: the length of acromion and the hook, and Group B, the thickness group: the thickness of acromion and the depth of hook. There are significant statistical differences when comparing between the subgroups within each group. The depth of the hook exceeds the thickness of the acromion (12.41±2.80?mm vs. 10.44±2.59?mm, respectively), the hook plate implantation significantly narrowed the subacromial space by 1.97±1.19?mm (p<0.01), and the length of the hook was shorter than that of the acromion by 9.75±3.64?mm (p<0.01). Our findings revealed that the hook plate with only 3 depths could not match the acromion satisfactorily and the hook plate implantation significantly narrowed the subacromial space. A hook plate with a variable depth, which can match better with patient's anatomy, is worthy of further investigation in the future. PMID:24577855

  13. Limb lengthening over plate

    PubMed Central

    Kulkarni, Ruta; Singh, Nishant; Kulkarni, Govind S; Kulkarni, Milind; Kulkarni, Sunil; Kulkarni, Vidisha

    2012-01-01

    Background: The limb lengthening over plate eliminates the associated risk of infection with limb lengthening over intramedullary nail. We present our experience of limb lengthening in 15 patients with a plate fixed on the proximal segment, followed by corticotomy and application of external fixator. Materials and Methods: 15 patients (7 females, 8 males) were included in this consecutive series. The average age was 18.1 years (range 8–35 years). Fifteen tibiae and one femur were lengthened in 15 patients. Lengthening was achieved at 1 mm/day followed by distal segment fixation with three or four screws on reaching the target length. Results: The preoperative target length was successfully achieved in all patients at a mean of 4.1 cm (range 1.8–6.5 cm). The mean duration of external fixation was 75.3 days (range 33–116 days) with the mean external fixation index at 19.2 days/cm (range 10.0–38.3 days/cm). One patient suffered deep infection up to the plate, three patients had mild procurvatum deformities, and one patient developed mild tendo achilles contracture. Conclusion: Lengthening over a plate allows early removal of external fixator and eliminates the risk of creating deep intramedullary infection as with lengthening over nail. Lengthening over plate is also applicable to children with open physis. PMID:22719123

  14. Tectonic Plates, Earthquakes, and Volcanoes

    NSDL National Science Digital Library

    According to theory of plate tectonics, Earth is an active planet -- its surface is composed of many individual plates that move and interact, constantly changing and reshaping Earth's outer layer. Volcanoes and earthquakes both result from the movement of tectonic plates. This interactive feature shows the relationship between earthquakes and volcanoes and the boundaries of tectonic plates. By clicking on a map, viewers can superimpose the locations of plate boundaries, volcanoes and earthquakes.

  15. Material Characterization of FGM Plates Using Elastic Waves and an Inverse Procedure

    Microsoft Academic Search

    G. R. Liu; X. Han; K. Y. Lam

    2001-01-01

    A computational inverse procedure is presented for characterization of the material properties of functionally graded materials (FGMs) using the surface displacement response of the plate. Amodified hybrid numerical method is first developed combining some existing techniques to compute the wave field in an FGM plate for given material properties and their variation in the thickness direction. The modified HNM allows

  16. A meshfree radial point interpolation method for analysis of functionally graded material (FGM) plates

    Microsoft Academic Search

    K. Y. Dai; G. R. Liu; K. M. Lim; X. Han; S. Y. Du

    2004-01-01

    A meshfree model is presented for the static and dynamic analyses of functionally graded material (FGM) plates based on the radial point interpolation method (PIM). In the present method, the mid-plane of an FGM plate is represented by a set of distributed nodes while the material properties in its thickness direction are computed analytically to take into account their continuous

  17. Nonlinear vibration and dynamic response of functionally graded plates in thermal environments

    Microsoft Academic Search

    Xiao-Lin Huang; Hui-Shen Shen

    2004-01-01

    This paper deals with the nonlinear vibration and dynamic response of functionally graded material plates in thermal environments. Heat conduction and temperature-dependent material properties are both taken into account. The temperature field considered is assumed to be a uniform distribution over the plate surface and varied in the thickness direction only. Material properties are assumed to be temperature-dependent, and graded

  18. VIBRATION CHARACTERISTICS AND TRANSIENT RESPONSE OF SHEAR-DEFORMABLE FUNCTIONALLY GRADED PLATES IN THERMAL ENVIRONMENTS

    Microsoft Academic Search

    J. Yang; H.-S. SHEN

    2002-01-01

    Free and forced vibration analyses for initially stressed functionally graded plates in thermal environment are presented. Material properties are assumed to be temperature dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Theoretical formulations are based on Reddy's higher order shear deformation plate theory and include

  19. CAPACITANCE EVALUATION ON PERPENDICULAR PLATE CAPACITORS BY MEANS OF FINITE ELEMENT ANALYSIS

    Microsoft Academic Search

    Jose-M. Bueno-Barrachina; César-S. Cañas-Peñuelas; S. Catalan-Izquierdo; Francisco Cavallé-Sesé

    In this work we show the influence of the edge-effect on the electric field distribution, and hence on inner capacitance and outer capacitance of the inclined angle, of a inclined-plate capacitor system in a plane, surrounded by an insulating medium taking into account the thickness of the conducting plates for a complete set of dimensions and insulating characteristics. Where available

  20. Support system design of the sub-mirror cell of the LAMOST Schmidt plate

    Microsoft Academic Search

    Dehua Yang; Fanghua Jiang

    2006-01-01

    The reflecting Schmidt plate of the Large sky Area Multi-Object Spectroscopic Telescope (LAMOST) is composed of 24 hexagonal segments, each of which is 1100 mm from corner to corner and 25 mm in thickness. Both segmented mirror active optics and deformable mirror active optics are involved in the Schmidt plate so as to compensate for optical aberration and structural deformation.

  1. Thermomechanical analysis of functionally graded material (FGM) plates using element-free Galerkin method

    Microsoft Academic Search

    K. Y. Dai; G. R. Liu; X. Han; K. M. Lim

    2005-01-01

    A meshfree model is presented for the active shape control as well as the dynamic response repression of the functionally graded material (FGM) plate containing distributed piezoelectric sensors and actuators. The FGM plate is assumed to be made of ceramics and metals whose volume fractions vary continuously in the thickness direction according to a power law. The element-free Galerkin method

  2. Design of laminated composite plates for optimal dynamic characteristics using a constrained global optimization technique

    Microsoft Academic Search

    T. Y. Kam; F. M. Lai

    1995-01-01

    The lamination arrangements of moderately thick laminated composite plates for optimal dynamic characteristics are studied via a constrained multi-start global optimization technique. In the optimization process, the dynamical analysis of laminated composite plates is accomplished by utilizing a shear deformable laminated composite finite element, in which the exact expressions for determining shear correction factors were adopted and the modal damping

  3. Design of laminated composite plates for optimal dynamic characteristics using a constrained global optimization technique

    Microsoft Academic Search

    T. Y. Kam; F. M. Lai

    1995-01-01

    The lamination arrangements of moderately thick laminated composite plates for optimal dynamic characteristics are studied via a constrained multi-start global optimization technique. In the optimization process, the dynamical analysis of laminated composite plates is accomplished by utilizing a shear deformable laminated composite finite element, in which the exact expressions for determining shear correction factors were adopted, and the modal damping

  4. Closed-Form Solutions of Three-Dimensional Functionally Graded Plates

    Microsoft Academic Search

    Zheng Zhong; Ertao Shang

    2008-01-01

    Three-dimensional analysis of a functionally graded plate is presented in this paper. The plate is subjected to normal and shear tractions of arbitrary form on the lower and upper surfaces while edge boundary conditions are given as simply supported. The problem is formulated on the assumption that the elastic modulus depends on the z-coordinate along the thickness direction. Plevako's solution

  5. Research of a Large Dielectric Plate Antenna Charging in Low-Altitude Polar Orbit Environment

    Microsoft Academic Search

    Wang Li; Liu Yang; Lu Yusun; Li Kai; Guo Shenhou

    1998-01-01

    This paper reports the study of the charging of a large dielectric plate antenna in low-altitude polar orbit plasma environment. The work presented here consists of three parts. First, the surface charging of the large dielectric plate antenna and its effects due to aurora precipitate electron are analyzed. The antenna surface could charge to kV magnitude because of its thick

  6. Assessing the Relationship between Central Corneal Thickness and Retinal Nerve Fiber Layer Thickness in Healthy Subjects

    PubMed Central

    Mumcuoglu, Tarkan; Townsend, Kelly A; Wollstein, Gadi; Ishikawa, Hiroshi; Bilonick, Richard A; Sung, Kyung Rim; Kagemann, Larry; Schuman, Joel S

    2008-01-01

    Purpose To determine the relationship between central corneal thickness (CCT) and retinal nerve fiber layer (RNFL) thickness obtained by scanning laser polarimetry (GDx-VCC; Carl Zeiss Meditec, Dublin, CA) confocal scanning laser ophthalmoscopy (HRT II; Heidelberg Engineering, Heidelberg, Germany) and optical coherence tomography (Stratus OCT; Carl Zeiss Meditec, Dublin, CA). Design Multi-center clinical trial, retrospective cross-sectional study. Methods One hundred and nine healthy subjects from the Advanced Imaging in Glaucoma Study were enrolled in this study. All subjects had a standard clinical examination, including visual field and good quality scans from all three imaging devices. Central corneal thickness was measured using an ultrasonic pachymeter. A linear mixed effects model was used to assess the relationship between RNFL thickness and CCT, accounting for clustering of eyes within subjects, testing site, ethnicity, family history of glaucoma, axial length intraocular pressure and visual field global indices. Results For OCT and GDx, there was a slight non-statistically significant positive relationship between CCT and RNFL thickness. For HRT, there was a slight non-statistically significant negative relationship between CCT and RNFL thickness. Relationships for each device were found to differ between sites. Conclusions CCT was not statistically significantly related to RNFL thickness in healthy eyes. PMID:18657796

  7. Static bending resistance of metal-plated joints constructed of oriented strandboard for upholstered furniture frames

    Microsoft Academic Search

    Xiaodong Wang; Mohammad Mohammad; Alexander Salenikovich; Robert M. Knudson; Jilei Zhang

    Metal-plate connectors are commonly used to connect critical joints in upholstered furniture frames due to their high load resistance, rapid assembly, and easy connection of members with uniform thickness. To successfully introduce oriented strand- board (OSB) into furniture frames, basic data for metal-plated joints constructed of OSB is needed. In this study, static moment capacity of T-shaped joints with metal-plates

  8. Experimental studies of quasi-longitudinal waves power flow in corrugated plates

    Microsoft Academic Search

    Nirmal Kumar Mandal

    2006-01-01

    The structural intensity technique using cross-spectral densities is used to estimate the quasi-longitudinal wave power in rectangular and trapezoidal corrugated plates in the frequency domain. The two-point transducer method for in-plane power in naturally orthotropic plate, whose thickness is uniform, is used for measuring in-plane vibration power transmission of these plates. The method of elastic equivalence is used to facilitate

  9. Got Standards? "Got Standards?"

    E-print Network

    Vardeman, Stephen B.

    increase reliability and quality, not to mention, make life a whole lot easier. Standards now known as ISO 9000 standards were developed by the International Organization for Standardization, which was founded in 1946. The purpose of the organization was to promote the development of international standards

  10. Brazed plate heat exchangers for geothermal applications

    SciTech Connect

    Rafferty, K. (Geo-Heat Center, Klamath Falls, OR (United States))

    1993-08-01

    Most geothermal fluids used for direct use purposes contain various chemical species which can be detrimental to conventional materials of construction. For this reason, the standard design practice is to isolate the geothermal fluid from the balance of the system through the use of a heat exchanger. In the majority of applications, the plate and frame heat exchanger has been the design of choice for this duty. Recently, a low-cost version of the plate heat exchanger, the brazed plate heat exchanger has become available. Due to their simpler construction these units can be economically produced in very small sizes. Considering the reduced cost these exchangers could greatly enhance the economics of small direct use geothermal systems. Brazed plate heat exchangers were placed in three geothermal fluids (Klamath Falls, OR; Boise, ID; and Pagosa Springs, CO) in order to determine the effect of H[sub 2]S on braze material. Based on subsequent analysis, it appears that the rate of corrosion of the braze material is much slower than corrosion of copper tube materials in the same fluids. Minimum expected life of the heat exchangers based on these corrosion rates is reported to be 12 years in fluids of less than 1 ppM H[sub 2]S and 10 years in fluids of less than 5 ppM. Based on these expected lives, and using a 3% inflation rate and 8% discount rate, brazed plate heat exchangers are a clear economic choice in which the capital cost is 50% or less of the cost of a plate and frame heat exchanger for the same duty. Due to their single pass design, brazed plate heat exchangers are generally limited to approach temperatures of 10[degrees]F or greater. Size limitations restrict applications to 100 gpm and/or 200 ft[sup 2] heat transfer surface area. 7 refs., 7 figs., 2 tabs.

  11. Stress Concentration Around an Open Circular Hole in a Plate Subjected to Bending Normal to the Plane of the Plate

    NASA Technical Reports Server (NTRS)

    Dumont, C

    1939-01-01

    An aluminum-alloy plate containing an open circular hole of diameter large compared with the thickness of the plate was subjected to bending forces normal to the plane of the plate. Deflection and strain measurements were taken for two different loads. Stress concentrations occurred at the edge of the hole and the maximum stresses were tangential to the hole at the ends of the transverse diameter. The maximum stress at the edge of the hole was 1.59 times the computed stress on the net section and 1.85 times the computed stress in a solid plate of the same dimensions subjected to the same bending forces. The maximum deflections were about 20 percent greater than the corresponding deflection for a solid plate of the same size subjected to the same bending forces. The smallest edge distance was equal to 2-1/2 times the diameter of the hole and the stress concentration on this side of the hole was the same as on the side where the edge distance was about 4-1/2 diameters. A theoretical analysis of the problem shows that, for an aluminum plate of infinite width, the stress concentration at the edge of the hole would be 1.87 times the stress in a solid plate, which is substantially the same relation obtained for the plate tested.

  12. 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 ...

  13. Flat plate project

    NASA Astrophysics Data System (ADS)

    Wijbrans, Klaas C.; Korsten, Maarten J.

    1991-03-01

    The flat plate project is a pilot study for the creation of intelligent robotic systems. In these systems vision robotics and artificial intelligence aspects have to be combined. The final goal is to give a robot the capacity to learn to solve the problem represented by a toy for a two year old child. This toy is called the ''Holle Bol'' in Dutch. It consists of a plastic ball with differently shaped holes in it and a number of small blocks that must be put into the corresponding holes. To investigate the problems associated with this project first a simplification of the problem has been studied. In this case a flat plate with differently shaped holes is used. The paper describes the results of the flat plate pilot project.

  14. Miniature plasmonic wave plates

    E-print Network

    Drezet, Aurelien; Ebbesen, Thomas W

    2010-01-01

    Linear birefringence, as implemented in wave plates, is a natural way to control the state of polarization of light. We report on a general method for designing miniature planar wave plates using surface plasmons. The resonant optical device considered here is a single circular aperture surrounded by an elliptical antenna grating. The difference in short and long axis of each ellipses introduces a phase shift on the surface plasmons which enables the realization of a quarter wave plate. Furthermore, the experimental results and the theoretical analysis show that the general procedure used does not influence the optical coherence of the polarization state and allows us to explore completely the surface of the unit Poincare sphere by changing only the shape of the elliptical grating.

  15. Miniature plasmonic wave plates.

    PubMed

    Drezet, Aurélien; Genet, Cyriaque; Ebbesen, Thomas W

    2008-07-25

    Linear birefringence, as implemented in wave plates, is a natural way to control the state of polarization of light. We report on a general method for designing miniature planar wave plates using surface plasmons. The resonant optical device considered here is a single circular aperture surrounded by an elliptical antenna grating. The difference between the short and long axis of each ellipsis introduces a phase shift on the surface plasmons which enables the realization of a quarter wave plate. Furthermore, the experimental results and the theoretical analysis show that the general procedure used does not influence the optical coherence of the polarization state and allows us to explore completely the surface of the unit Poincaré sphere by changing only the shape of the elliptical grating. PMID:18764329

  16. Nitrided Metallic Bipolar Plates

    SciTech Connect

    Brady, Michael P [ORNL; Tortorelli, Peter F [ORNL; Pihl, Josh A [ORNL; Toops, Todd J [ORNL; More, Karren Leslie [ORNL; Meyer III, Harry M [ORNL; Vitek, John Michael [ORNL; Wang, Heli [National Renewable Energy Laboratory (NREL); Turner, John [National Renewable Energy Laboratory (NREL); Wilson, Mahlon [Los Alamos National Laboratory (LANL); Garzon, Fernando [Los Alamos National Laboratory (LANL); Rockward, Tommy [Los Alamos National Laboratory (LANL); Connors, Dan [GenCell Corp; Rakowski, Jim [Allegheny Ludlum; Gervasio, Don [Arizona State University

    2008-01-01

    The objectives are: (1) Develop and optimize stainless steel alloys amenable to formation of a protective Cr-nitride surface by gas nitridation, at a sufficiently low cost to meet DOE targets and with sufficient ductility to permit manufacture by stamping. (2) Demonstrate capability of nitridation to yield high-quality stainless steel bipolar plates from thin stamped alloy foils (no significant stamped foil warping or embrittlement). (3) Demonstrate single-cell fuel cell performance of stamped and nitrided alloy foils equivalent to that of machined graphite plates of the same flow-field design ({approx}750-1,000 h, cyclic conditions, to include quantification of metal ion contamination of the membrane electrode assembly [MEA] and contact resistance increase attributable to the bipolar plates). (4) Demonstrate potential for adoption in automotive fuel cell stacks. Thin stamped metallic bipolar plates offer the potential for (1) significantly lower cost than currently-used machined graphite bipolar plates, (2) reduced weight/volume, and (3) better performance and amenability to high volume manufacture than developmental polymer/carbon fiber and graphite composite bipolar plates. However, most metals exhibit inadequate corrosion resistance in proton exchange membrane fuel cell (PEMFC) environments. This behavior leads to high electrical resistance due to the formation of surface oxides and/or contamination of the MEA by metallic ions, both of which can significantly degrade fuel cell performance. Metal nitrides offer electrical conductivities up to an order of magnitude greater than that of graphite and are highly corrosion resistant. Unfortunately, most conventional coating methods (for metal nitrides) are too expensive for PEMFC stack commercialization or tend to leave pinhole defects, which result in accelerated local corrosion and unacceptable performance.

  17. Tectonic Plate Motion

    NSDL National Science Digital Library

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

  18. License plate detection algorithm

    NASA Astrophysics Data System (ADS)

    Broitman, Michael; Klopovsky, Yuri; Silinskis, Normunds

    2013-12-01

    A novel algorithm for vehicle license plates localization is proposed. The algorithm is based on pixel intensity transition gradient analysis. Near to 2500 natural-scene gray-level vehicle images of different backgrounds and ambient illumination was tested. The best set of algorithm's parameters produces detection rate up to 0.94. Taking into account abnormal camera location during our tests and therefore geometrical distortion and troubles from trees this result could be considered as passable. Correlation between source data, such as license Plate dimensions and texture, cameras location and others, and parameters of algorithm were also defined.

  19. 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.

  20. Plate Tectonics and Volcanism

    NSDL National Science Digital Library

    2012-08-03

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

  1. Plating under reduced pressure

    SciTech Connect

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

    1992-06-01

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

  2. Volcanoes, Plates, and Chains

    NSDL National Science Digital Library

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

  3. Discovering Plate Boundaries

    NSDL National Science Digital Library

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

  4. The effects of the overriding plate thermal state on the slab dip in an ocean-continent subduction system

    NASA Astrophysics Data System (ADS)

    Roda, Manual; Marotta, Anna Maria; Iolle Spalla, Maria

    2011-05-01

    To evaluate the effects of variations in the thermal state of the overriding plate on the slab dip in an ocean-continent subduction system, a 2-D finite element thermo-mechanical model was implemented. The lithosphere base was located at the depth of the 1600 K isotherm. Numerical simulations were performed while taking into account four different initial thicknesses for the oceanic lithosphere (60, 80, 95 and 110 km) and five different thicknesses of the overriding plate, as compared in terms of the continental-oceanic plate thickness ratio (100, 120, 140, 160 and 200% of the oceanic lithosphere thickness). The results of numerical modeling indicate that a high variability of the subducting plate geometry occurs for an oceanic lithosphere thickness ranging from 60 to 80 km, while the variability decreases where the oceanic plates are thicker (95 and 110 km). Furthermore, the slab dip strongly depends on the thermal state of the overriding plate, and, in particular, the slab dip decreases with the increase in the upper plate thickness. The model predictions also confirm that a direct correlation between the slab dip and the age of the oceanic lithosphere does not exist, at least for subduction plates thinner that 110 km. These conclusions are supported by the good agreement between the model results and the natural data referring to worldwide ocean-continent subduction zones.

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

    NASA Astrophysics Data System (ADS)

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

    2008-02-01

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

  6. Liquid film thickness measurement by two-line TDLAS

    SciTech Connect

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

    2014-04-11

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

  7. A high-resolution local network study of the Nazca plate Wadati-Benioff zone under western Argentina

    NASA Technical Reports Server (NTRS)

    Smalley, Robert F., Jr.; Isacks, Bryan L.

    1987-01-01

    Seismic data, recorded by INPRES telemetered network located above one of the subhorizontal segments of the subducted Nazca plate Wadati-Benioff zone beneath western Argentina, were analyzed to determine the zone's fine structure. The depth of the center and the thickness of the subhorizontal Wadati-Benioff zone beneath the network were calculated to be about 107 km and about 20 km, respectively, with most of the seismogenic zone concentrated in a region about 12 km thick. The Nazca plate is interpreted to be in a state of down-dip tension and to be decoupled from the overriding South American plate by a weak zone of asthenospheric or shear-heated material. The South American plate is estimated to be 80 km thick, based on the location of the subducted Nazca plate and an inferred decoupling zone between the plates.

  8. Theory and performance of plated thermocouples.

    NASA Technical Reports Server (NTRS)

    Pesko, R. N.; Ash, R. L.; Cupschalk, S. G.; Germain, E. F.

    1972-01-01

    A theory has been developed to describe the performance of thermocouples which have been formed by electroplating portions of one thermoelectric material with another. The electroplated leg of the thermocouple was modeled as a collection of infinitesimally small homogeneous thermocouples connected in series. Experiments were performed using several combinations of Constantan wire sizes and copper plating thicknesses. A transient method was used to develop the thermoelectric calibrations, and the theory was found to be in quite good agreement with the experiments. In addition, data gathered in a Soviet experiment were also found to be in close agreement with the theory.

  9. 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.

  10. 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.

  11. 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.

  12. Impact response of thick glass fibre reinforced polyester laminates

    Microsoft Academic Search

    G. Zhou; G. A. O. Davies

    1995-01-01

    Thick glass\\/polyester woven roving laminated plates subject to low-velocity impact have been investigated using a guided drop-weight test rig in ascending energy order up to 1500 J. The impact response and energy-absorbing characteristics have been determined by impact-forces and absorbed-energy histories, and by force-displacement relationships. Impact damage is examined by visual inspection, ultrasonic C-scan and an optical microscope so that

  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. Earthquakes and Plates

    NSDL National Science Digital Library

    The representation depicts global distribution of earthquakes. A world map shows the location of large earthquakes that occurred from 1975-1995. A slider at the bottom left of the map allows the user to change the map to reveal the location of major plates or to select both views layered on top of one another.

  17. University Center Plated Entrees

    E-print Network

    Lee, Herbie

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

  18. Plate Tectonics Quiz

    NSDL National Science Digital Library

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

  19. Plate Tectonics: Lines of Evidence

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2006-11-01

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

  20. Earth: Plates on the Move

    NSDL National Science Digital Library

    In this activity, students explore how the movement of tectonic plates forms mountains, volcanoes, oceans, and earthquakes. It first describes the plates and the various types of interaction at plate boundaries. An interactive map of the world shows the relationship between plate boundaries and earthquakes, allowing the student to click on selected place to explore a volcano, mountain, hotspot or earthquake. They then zoom in the see how the plates are moving, play an animation about the plate interaction, and read a story about the event. In addition, a set of links lead to more detailed information.

  1. 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.

  2. 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.

  3. 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.

  4. Crustal Thickness Along the Central American Volcanic Arc

    NASA Astrophysics Data System (ADS)

    Auger, L. S.; Abers, G.; Rossi, G.; Plank, T.; Fischer, K.; Gonzalez, V.; Protti, M.; Strauch, W.

    2004-12-01

    Crustal thickness of volcanic arcs in subduction zones has been used to infer the time-integrated rate of mantle melting and the consequent rate of continental growth. Subduction of the Cocos Plate under the Caribbean Plate results in active volcanism in Central America. Tomography Under Costa Rica And Nicaragua (TUCAN) is an eighteen month broadband seismic experiment that began in the summer of 2004 with the goal of seismically imaging the upper mantle and subducting slab. Forty-eight IRIS/PASSCAL instruments were installed in two densely spaced cross-arc lines and two arc-parallel lines. Initial analysis has focused on three permanent and one pilot station in the region. Receiver functions calculated from teleseismic events recorded on these stations have strong signals from the Moho as well as a signal from a dipping slab, exhibiting a strong tangential component. The P-to-S conversions from the Moho seen in receiver functions in Costa Rica have approximately a two second delay relative to those in Nicaragua, indicating crustal thickening from Nicaragua into Costa Rica. A station in Costa Rica has an estimated crustal thickness of thirty to thirty-one kilometers whereas a station in Nicaragua has a thickness between forty and forty five kilometers depending on the velocity models used. This is consistent with previous crustal thickness estimates from Bouguer gravity and regional elevation, assuming Airy isostasy, meaning that elevation is controlled by crustal thickness. The difference in crustal thickness between Nicaragua and Costa Rica could be the result of different rates of crustal growth, or more likely, tectonic changes to crustal thickness (as a result of extension or compression) in one or both places.

  5. Plate Puzzle Page 1 of 20 Plate Puzzle 1

    E-print Network

    Benitez-Nelson, Claudia

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

  6. Interpolating Mean Rainfall Using Thin Plate Smoothing Splines

    Microsoft Academic Search

    M. F. Hutchinson

    1995-01-01

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

  7. 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...

  8. Analyses of functionally graded plates with a magnetoelectroelastic layer

    NASA Astrophysics Data System (ADS)

    Sladek, J.; Sladek, V.; Krahulec, S.; Pan, E.

    2013-03-01

    A meshless local Petrov-Galerkin (MLPG) method is presented for the analysis of functionally graded material (FGM) plates with a sensor/actuator magnetoelectroelastic layer localized on the top surface of the plate. The Reissner-Mindlin shear deformation theory is applied to describe the plate bending problem. The expressions for the bending moment, shear force and normal force are obtained by integration through the FGM plate and magnetoelectric layer for the corresponding constitutive equations. Then, the original three-dimensional (3D) thick-plate problem is reduced to a two-dimensional (2D) problem. Nodal points are randomly distributed over the mean surface of the considered plate. Each node is the center of a circle surrounding the node. The weak-form on small subdomains with a Heaviside step function as the test function is applied to derive local integral equations. After performing the spatial MLS approximation, a system of ordinary differential equations of the second order for certain nodal unknowns is obtained. The derived ordinary differential equations are solved by the Houbolt finite-difference scheme. Pure mechanical loads or electromagnetic potentials are prescribed on the top of the layered plate. Both stationary and transient dynamic loads are analyzed.

  9. 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.

  10. 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.

  11. Orthodontic skeletal anchorage using a palatal external plate.

    PubMed

    Kobayashi, Masaru; Fushima, Kenji

    2014-03-01

    We have developed the Anchor-Lock external plate system, which is fitted on the palate for the purpose of orthodontic skeletal anchorage. The aim of this study was to introduce the Anchor-Lock and assess its success rate. The Anchor-Lock is composed of titanium screws of 2·0-mm diameter and a titanium plate of 1·0-mm thickness. The external plate is rigidly interlocked with the heads of the screws, which are implanted trans-mucosally into palatal bone. Three types of Anchor-Lock are available. These were applied to 137 orthodontic patients (104 females and 33 males) aged 10-54 years. Two types of plate were used, a straight-shaped plate applied to the hard palate and to the anterior palate and a double-Y-shaped plate applied after tooth-borne rapid maxillary expansion. Success rate of the Anchor-Lock was 92·0% overall. No significant difference in success rate was found by age or sex of patients. Type or screw length of the Anchor-Lock did not affect success rate significantly. Success rate was significantly increased by the use of the surgical stent. The Anchor-Lock was effectively applied to distalize and/or intrude the upper molars. The Anchor-Lock system appears suitable for clinical use as an alternative to conventional screw- and plate-type orthodontic implants. PMID:24671290

  12. The origin of thick discs

    NASA Astrophysics Data System (ADS)

    Comerón, Sébastien

    2015-03-01

    Thick discs are defined to be disc-like components with a scale height larger than that of the classical discs. They are ubiquitous (Yoachim & Dalcanton 2006; Comerón et al. 2011a), they are made of mostly old and metal-poor stars and are most easily detected in close to edge-on galaxies. Their origin has been considered mysterious and several formation theories have been proposed: • The thick disc being formed secularly by thin disc stars heated by disc overdensities such as giant molecular clouds or spiral arms (Villumsen 1985, ApJ, 290, 75) and by stars moved outwards from their original orbits by radial migration mechanisms (Schönrich & Binney 2009). • The thick disc being formed by the heating of the thin disc by satellites (Quinn et al. 1993) and the tidal stripping of them (Abadi et al. 2003). • The thick disc being formed fast and already thick at high redshift in an highly unstable disc. Inside that thick disc, a thin disc would form afterwards as suggested by Elemgreen & Elmegreen (2006). • The thick disc being formed originally thick at high redshift by the merger of gas-rich protogalactic fragments and a thin disc forming afterwards within it (Brook et al. 2007). The first mechanism is a secular evolution mechanism. The time-scale of the second one is dependent on the merger history of the main galaxy. In the two last mechanisms, the thick disc forms already thick in a short time-scale at high redshift. Recent Milky Way studies, (see, e.g., Bovy et al. 2012), have shown indications that there is no discontinuity between the thin and the thick disc chemical and kinematic properties. Instead, those studies indicate the presence of a monotonic distribution of disc thicknesses. This would suggest a secular origin for the Milky Way thick disc. Studies in external galaxies (Yoachim & Dalcanton 2006; Comerón et al. 2011b), have shown that low-mass disc galaxies have thick disc relative masses much larger than those found in large-mass galaxies. Because low-mass galaxies are dynamically younger than their larger counterparts, it seems difficult for their thick discs to have a secular evolution origin, but simulations show that their thick disc masses are compatible with those of a thick disc formed at high redshift. Thus, recent studies seem to indicate that large-mass galaxies have their thick discs formed mainly due to secular evolution and that low-mass galaxies have them formed at high redshift.

  13. Renewable liquid reflecting zone plate

    DOEpatents

    Toor, Arthur; Ryutov, Dmitri D.

    2003-12-09

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

  14. Plate Tectonics: Lake Mead, Nevada

    NSDL National Science Digital Library

    2005-10-21

    Using animations to illustrate the theory of plate tectonics, this video segment adapted from Discovering Women takes you to Lake Mead, Nevada, to see visual evidence of how plate movement has been stretching the North American continent.

  15. Tectonic Plates, Earthquakes, and Volcanoes

    NSDL National Science Digital Library

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

  16. What Are Growth Plate Injuries?

    MedlinePLUS

    ... for growth plate injuries are: ? Falling down ? Competitive sports (like football) ? Recreational activities. Other reasons for growth plate injuries are: ? Child abuse ? Injury from extreme cold (for example, frostbite) ? Radiation ( ...

  17. What Are Growth Plate Injuries?

    MedlinePLUS

    ... for growth plate injuries are: Falling down Competitive sports (like football) Recreational activities. Other reasons for growth plate injuries are: Child abuse Injury from extreme cold (for example, frostbite) Radiation ( ...

  18. 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.

  19. 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.

  20. Flexural vibration of perforated plates and porous elastic materials under acoustic loading.

    PubMed

    Takahashi, D; Tanaka, M

    2002-10-01

    This paper presents a method of theoretical treatment of acoustic coupling due to flexural vibration of perforated plates and plates of porous elastic materials. The analytical model is developed by introducing flow continuity at the plate surface in a spatially mean sense and air-solid interaction within the plate material. To demonstrate the method of application, some fundamental acoustic problems based on a classical thin-plate theory are analyzed and discussed in relation to the interactive effect of flexural vibration and plate permeability. For acoustic radiation from a vibrating plate excited by a harmonic point-force, the attenuation effect of power radiation appears at frequencies below the critical frequency of coincidence. In the problem of sound absorption of a perforated plate or a plate of porous elastic material backed by an air layer, as permeability decreases, the effect of plate vibration increases. For perforated absorber systems including plate vibration effects, the trend of variation from ordinary theory depends on plate thickness. PMID:12398453

  1. Radiation efficiency of damped plates.

    PubMed

    Kou, Yiwei; Liu, Bilong; Tian, Jing

    2015-02-01

    The radiation efficiency of damped plates is discussed in this letter. Below the critical frequency of a plate, numerical results show that the radiation efficiency is much influenced by damping. Some modifications of the classical formulas given by Cremer for an infinite plate and Leppington for a finite rectangular plate are proposed to include the influence of the damping on the radiation efficiency. PMID:25698034

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

    NASA Astrophysics Data System (ADS)

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

    2004-05-01

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

  3. 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.

  4. THE PARALLEL PLATE PLASMA PROBLEM

    Microsoft Academic Search

    Hall

    1962-01-01

    The parallel plate plasma problem is considered under the assumption of ; uniform density and a specular reflection boundary condition at the plates. The ; impedance of the device is derived for several different models of the plasma ; medium. The impedance of a hydromagnetic medium exhibits resonances whenever the ; plate separation is an odd multiple of a half

  5. Lesson 3. Plate Tectonics Overview

    E-print Network

    Chen, Po

    Lesson 3. Plate Tectonics #12;Overview · Prior to the 1970s that with the development of the theory of plate tectonics. · Knowledge of the ocean floors of the Earth #12;Overview · Plate tectonics explains the formaBon of the Earth's two

  6. Glacial isostasy and plate motion

    Microsoft Academic Search

    Volker Klemann; Zdenek Martinec; Erik R. Ivins

    2008-01-01

    The influence of glacial-isostatic adjustment (GIA) on the motion of tectonic plates is usually neglected. Employing a recently developed numerical approach, we examine the effect of glacial loading on the motion of the Earth’s tectonic plates where we consider an elastic lithosphere of laterally variable strength and the plates losely connected by low viscous zones. The aim of this paper

  7. Registration based cortical thickness measurement.

    PubMed

    Das, Sandhitsu R; Avants, Brian B; Grossman, Murray; Gee, James C

    2009-04-15

    Cortical thickness is an important biomarker for image-based studies of the brain. A diffeomorphic registration based cortical thickness (DiReCT) measure is introduced where a continuous one-to-one correspondence between the gray matter-white matter interface and the estimated gray matter-cerebrospinal fluid interface is given by a diffeomorphic mapping in the image space. Thickness is then defined in terms of a distance measure between the interfaces of this sheet like structure. This technique also provides a natural way to compute continuous estimates of thickness within buried sulci by preventing opposing gray matter banks from intersecting. In addition, the proposed method incorporates neuroanatomical constraints on thickness values as part of the mapping process. Evaluation of this method is presented on synthetic images. As an application to brain images, a longitudinal study of thickness change in frontotemporal dementia (FTD) spectrum disorder is reported. PMID:19150502

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. 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.