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1

Thickness-shear approximation for piezoelectric ceramic plates  

Microsoft Academic Search

The thickness-shear mode in piezoelectric ceramic plates has been analysed theoretically with the approximate two-dimensional plate theory. The theoretical dispersion for a fully electroded infinite plate has been compared with experimental results on rectangular plate resonators. Limits of the application of the thickness-shear approximation related to the plate geometry have been established.

V. L. STRASHILOV; M. M. NADOLIISKI

1989-01-01

2

Plate Thickness Variation Effects on Crack Growth Rates in 7050-T7451 Alloy Thick Plate  

NASA Astrophysics Data System (ADS)

A study has been accomplished to characterize the fatigue crack growth rates and mechanisms in thick plate (16.51 cm) commercial grade 7050-T7451 aluminum plate in the L-S orientation. Examination of the effects of potential property gradients in the plate material was accomplished through hardness measurements along the short transverse direction and with compact tension tests. Tests exhibited a distinct trend of reduced center plane hardness in the plates. Compact tension specimens and the compliance method were used to determine crack growth rates for specimens machined from the t/4 and t/2 planar locations and oriented for L-S crack growth. Crack growth rate data (long crack) from the tests highlighted significant growth rate differences between the t/4 and t/2 locations. No significant effect of R-ratio was observed in the 0.05-0.3 range tested. Additionally, crack front splitting was noted in all specimens to differing degrees with data showing significant retardation of growth rate curves for the L-S orientation above 13 MPa ?m in the center plane, and 10 MPa ?m at quarter plane, where branching and splitting parallel to the load axis are dominant growth mechanisms.

Schubbe, Joel J.

2011-02-01

3

Accurate vibration analysis of thick, cracked rectangular plates  

Microsoft Academic Search

This work applies the Ritz method to accurately determine the frequencies and nodal patterns of thick, cracked rectangular plates analyzed using Mindlin plate theory. Two types of cracked configuration are considered, namely, side crack and internal crack. To enhance the capabilities of the Ritz method in dealing with cracked plates, new sets of admissible functions are proposed to represent the

C. S. Huang; A. W. Leissa; R. S. Li

2011-01-01

4

Design of a Variable Thickness Plate to Focus Bending Waves  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

5

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

SciTech Connect

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

Inui, Norio [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2201 (Japan)

2011-11-15

6

Trapped thickness-twist modes in an inhomogeneous piezoelectric plate  

NASA Astrophysics Data System (ADS)

We show the existence of certain thickness-twist modes in an unbounded, inhomogeneous piezoelectric plate of crystals with 6-mm symmetry or in polarized ceramics. The modes found are trapped, with the vibration confined to a portion of the plate. These modes are exact and satisfy the three-dimensional equations of piezoelectricity. Potentially, they can be used as the operating modes of plate resonators and acoustic wave sensors, in particular, thin film resonators of ZnO and AlN.

Yang, J.; Chen, Z.; Hu, Y.

2006-11-01

7

Thermoelastic buckling response of thick functionally graded plates  

NASA Astrophysics Data System (ADS)

The thermoelastic buckling behavior of a thick plate made of a functionally graded material is investigated in this paper by using an exponential shear deformation plate theory. A simple power law based on the rule of mixtures is used to estimate the effective material properties as functions of the plate thickness. The neutral surface position for such functionally graded plates is determined on the basis of the nonlinear strain-displacement relations. Uniform, linear, and nonlinear temperature distributions across the plate are considered. An analytical approach is presented to find the critical buckling temperature, which can be used in engineering calculations. A numerical solution of the problem with the use of an exponential dependence for shear strains is presented. The results obtained are compared with available data.

Tebboune, W.; Merdjah, M.; Benrahou, K. H.; Tounsi, A.

2014-09-01

8

Stability and vibration of thick laminated composite sector plates  

NASA Astrophysics Data System (ADS)

This study presents a simple analytical formulation for the eigenvalue problem of buckling and free vibration analysis of shear deformable laminated sector plates made up of cylindrically orthotropic layers. The non-axisymmetric formulation in cylindrical coordinates is discretized in space domain in terms of two-dimensional Chebyshev polynomials. Several combinations of simply supported, clamped and free edge conditions are considered. Convergence study has been carried out and the obtained results are compared with the results of laminated square plates and isotropic sector plates available in literature. Extensive results pertaining to critical buckling loads and natural frequencies are presented. Effects of boundary conditions, number of layers, moduli ratio, rotary and in-plane inertia, plate thickness, sector angle and annularity are studied.

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

2005-10-01

9

Growth defects in thick ion-plated coatings  

NASA Technical Reports Server (NTRS)

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

Spalvins, T.

1975-01-01

10

Holographic inspection of plates containing areas of localized thickness variation  

SciTech Connect

Circular plates, under unknown clamping conditions and containing simulated defects in the form of circular localized thinning or thickening, are inspected by double-exposure holography. With an incremental uniform pressure applied between exposures, eccentric defects are readily revealed from the distinct irregular fringe patterns. In the case of central circular defects, however, the absence of distinct irregular fringe patterns does not enable easy visual detection of the defects. The simple method of analysis described in this paper, based on the fact that the displacement in a defective plate differs from that in a defect-free plate, alloys easy deduction of central and eccentric defects from the fringe patterns. Furthermore, this method enables identification of the type of defect (localized thinning or thickening), the extent of thickness variation, as well as an accurate estimation of the location and size of the defect.

Shang, H.M.; Lwin, M.; Tay, T.E. (National Univ. of Singapore, Kent Ridge (Singapore))

1994-04-01

11

Incremental ECAP of thick continuous plates - machine and initial trials  

NASA Astrophysics Data System (ADS)

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 (10501000) 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.

Rosochowski, A.; Olejnik, L.

2014-08-01

12

? 3 Hierarchy plate theories for thick and thin composite plates: The generalized unified formulation  

Microsoft Academic Search

Each displacement component is expanded along the thickness of the plate by using a powerful compact formulation. Infinite different types of expansions can be independently used for the displacements ux, uy and uz. Therefore, the present formulation here introduced for the first time, leads to the writing, with a single formal theory, of a class of ?3 theories. These theories

Luciano Demasi

2008-01-01

13

49 CFR 179.200-6 - Thickness of plates.  

Code of Federal Regulations, 2010 CFR

...pressure in psig; S = Minimum tensile strength of plate material in p.s...pressure in psig; S = Minimum tensile strength of plate material in p.s...pressure in psig; S = Minimum tensile strength of plate material in...

2010-10-01

14

49 CFR 179.200-6 - Thickness of plates.  

Code of Federal Regulations, 2011 CFR

...pressure in psig; S = Minimum tensile strength of plate material in p.s...pressure in psig; S = Minimum tensile strength of plate material in p.s...pressure in psig; S = Minimum tensile strength of plate material in...

2011-10-01

15

49 CFR 179.200-6 - Thickness of plates.  

Code of Federal Regulations, 2013 CFR

...pressure in psig; S = Minimum tensile strength of plate material in p.s...pressure in psig; S = Minimum tensile strength of plate material in p.s...pressure in psig; S = Minimum tensile strength of plate material in...

2013-10-01

16

49 CFR 179.200-6 - Thickness of plates.  

Code of Federal Regulations, 2012 CFR

...pressure in psig; S = Minimum tensile strength of plate material in p.s...pressure in psig; S = Minimum tensile strength of plate material in p.s...pressure in psig; S = Minimum tensile strength of plate material in...

2012-10-01

17

Estimates of elastic plate thicknesses beneath large volcanos on Venus  

NASA Technical Reports Server (NTRS)

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.

Mcgovern, Patrick J.; Solomon, Sean C.

1992-01-01

18

49 CFR 179.220-6 - Thickness of plates.  

Code of Federal Regulations, 2013 CFR

...required bursting pressure in psig; S = Minimum tensile strength of plate material in p.s.i. as prescribed in...required bursting pressure in psig; S = Minimum tensile strength of plate material in psi as prescribed in AAR...

2013-10-01

19

49 CFR 179.220-6 - Thickness of plates.  

Code of Federal Regulations, 2012 CFR

...required bursting pressure in psig; S = Minimum tensile strength of plate material in p.s.i. as prescribed in...required bursting pressure in psig; S = Minimum tensile strength of plate material in psi as prescribed in AAR...

2012-10-01

20

49 CFR 179.220-6 - Thickness of plates.  

Code of Federal Regulations, 2010 CFR

...required bursting pressure in psig; S = Minimum tensile strength of plate material in p.s.i. as prescribed in...required bursting pressure in psig; S = Minimum tensile strength of plate material in psi as prescribed in AAR...

2010-10-01

21

49 CFR 179.220-6 - Thickness of plates.  

Code of Federal Regulations, 2011 CFR

...required bursting pressure in psig; S = Minimum tensile strength of plate material in p.s.i. as prescribed in...required bursting pressure in psig; S = Minimum tensile strength of plate material in psi as prescribed in AAR...

2011-10-01

22

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

Microsoft Academic Search

Laser-assisted stir welding is a hybrid process that combines energy from a laser with functional heating and mechanical energy to join materials in the solid state. The technology is an adaptation of friction stir welding which is particularly suited for joining thick plates. Aluminum plates up to 75 mm thick have been successfully joined using friction stir welding. Since joining

Keith M. Williamson

2002-01-01

23

The BEM for plates of variable thickness on nonlinear biparametric elastic foundation. An analog equation solution  

Microsoft Academic Search

The BEM is developed for the analysis of plates with variable thickness resting on a nonlinear biparametric elastic foundation. The presented solution is achieved using the Analog Equation Method (AEM). According to the AEM the fourth-order partial differential equation with variable coefficients describing the response of the plate is converted to an equivalent linear problem for a plate with constant

J. T. Katsikadelis; A. J. Yiotis

2003-01-01

24

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

Microsoft Academic Search

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

Seyyed M. Hasheminejad; Ahmad Rafsanjani

2009-01-01

25

49 CFR 179.100-6 - Thickness of plates.  

Code of Federal Regulations, 2010 CFR

...s.i.; S = Minimum tensile strength of plate material in p.s...are clad with material having tensile strength properties at least equal...cladding material does not have tensile strength at least equal to the...

2010-10-01

26

49 CFR 179.100-6 - Thickness of plates.  

Code of Federal Regulations, 2012 CFR

...s.i.; S = Minimum tensile strength of plate material in p.s...are clad with material having tensile strength properties at least equal...cladding material does not have tensile strength at least equal to the...

2012-10-01

27

49 CFR 179.300-6 - Thickness of plates.  

Code of Federal Regulations, 2013 CFR

...pressure in psig; S = minimum tensile strength of plate material in p.s...are clad with material having tensile strength at least equal to the base...cladding material does not have tensile strength at least equal to the...

2013-10-01

28

49 CFR 179.300-6 - Thickness of plates.  

Code of Federal Regulations, 2010 CFR

...pressure in psig; S = minimum tensile strength of plate material in p.s...are clad with material having tensile strength at least equal to the base...cladding material does not have tensile strength at least equal to the...

2010-10-01

29

49 CFR 179.100-6 - Thickness of plates.  

Code of Federal Regulations, 2013 CFR

...s.i.; S = Minimum tensile strength of plate material in p.s...are clad with material having tensile strength properties at least equal...cladding material does not have tensile strength at least equal to the...

2013-10-01

30

49 CFR 179.300-6 - Thickness of plates.  

Code of Federal Regulations, 2012 CFR

...pressure in psig; S = minimum tensile strength of plate material in p.s...are clad with material having tensile strength at least equal to the base...cladding material does not have tensile strength at least equal to the...

2012-10-01

31

49 CFR 179.300-6 - Thickness of plates.  

Code of Federal Regulations, 2011 CFR

...pressure in psig; S = minimum tensile strength of plate material in p.s...are clad with material having tensile strength at least equal to the base...cladding material does not have tensile strength at least equal to the...

2011-10-01

32

49 CFR 179.100-6 - Thickness of plates.  

Code of Federal Regulations, 2011 CFR

...s.i.; S = Minimum tensile strength of plate material in p.s...are clad with material having tensile strength properties at least equal...cladding material does not have tensile strength at least equal to the...

2011-10-01

33

Earthquakes, Plate Boundaries, and Depth Indiana Standard Indicators  

E-print Network

Earthquakes, Plate Boundaries, and Depth Indiana Standard Indicators: ES.1.23 ­ Explain motions the movement of the plates that make up the crust of the earth and the resulting formation of earthquakes Voyager, Jr." to correlate and assess the location of earthquakes and plate boundaries, the age

Polly, David

34

A simple method to measure the thickness and order number of a wave plate  

NASA Astrophysics Data System (ADS)

Thickness and order number are important parameters for a wave plate in optical experiments. However, the encapsulation of the wave plate makes its thickness difficult to measure directly. In this paper, we propose an indirect measurement method to obtain the thickness and order number of a uniaxial crystal wave plate. With this method only the maximum and minimum values of the optical power of the transmitted light through the wave plate are measured in the experiment by rotating the wave plate around its optical axis. This simple method is easy to realize in the college physics laboratory, and it is also of importance for students to further understand the underlying physics of the wave plates.

Hu, Yichuan; Yi, Zhenglei; Yang, Hujiang; Xiao, Jinghua

2013-09-01

35

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

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

36

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

PubMed

Energy trapping has important applications in the design of thickness-shear resonators. Considerable efforts have been made for the effective utilization and improvement of energy trapping with variations of plate configurations, such as adding electrodes and contouring. As a new approach in seeking improved energy trapping feature, we analyze thickness-shear vibrations in an elastic plate with functionally graded material (FGM) of in-plane variation of mechanical properties, such as elastic constants and density. A simple and general equation governing the thickness-shear modes is derived from a variational analysis. A plate with piecewise constant material properties is analyzed as an example. It is shown that such a plate can support thickness-shear vibration modes with obvious energy trapping. Bechmann's number for the existence of only one trapped mode also can be determined accordingly. PMID:17375839

Wang, Ji; Yang, Jiashi; Li, Jiangyu

2007-03-01

37

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

38

Nonlinear transient analysis of moderately thick laminated composite sector plates  

NASA Astrophysics Data System (ADS)

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

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

2007-09-01

39

Convective Heat Transfer from a Thick Hemispherical Plate during Free Liquid Jet Impingement  

Microsoft Academic Search

Convective heat transfer during free liquid jet impingement on a hemispherical solid plate of finite thickness has been examined. The model included the entire fluid region (impinging jet and flow spreading out over the hemispherical surface) and solid plate as a conjugate problem. Solution was done for both isothermal and constant heat flux boundary conditions at the inner surface of

Muhammad M. Rahman; Jorge C. Lallave; Cesar F. Hernandez

2008-01-01

40

Bending of an axisymmetrically loaded thick circular plate on a granular half-space  

Microsoft Academic Search

A numerical procedure is presented for the determination of the contact pressure, bending moment distributions and the displacements of an axisymmetrically loaded thick circular plate which rests without friction on a granular or on an isotropic elastic half-space. Some numerical results are presented which show the effect of the various parameters on the mechanical behaviour of the plate.

E. N. Mastrojannis

1989-01-01

41

The displacement field in the vibration analysis of laminated thick plates  

SciTech Connect

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.

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

1995-11-01

42

Prediction of bending limits in friction-stir-processed thick plate aluminum  

NASA Astrophysics Data System (ADS)

Friction-stir processing (FSP) was used to modify surface microstructures, to enhance the bending of thick-plate 6061-T6 and 7050-T7451 aluminum alloys. Plates were bent at room temperature into a V-shaped die, to various angles. Bending performance in the friction-stir-processed plates was significantly better than that in the base plates, where processing caused localized softening of the pretensile surface of the plate. A finite-element model of the plate-bending process was developed, to predict the bending limits of both the unprocessed base plates and of the friction-stir-processed plates. For the friction-stir-processed plates, the model employed a mesh divided into two or more zones; one zone was for unprocessed base material and other zones were for the processed material or for material that was affected by the heat of processing. The model used both the von Mises and the Latham and Cockroft criteria to predict bending limits. The bending-limit predictions were reasonably accurate, provided the gradient in true stress-strain behavior through the plate thickness was well characterized.

Miles, M. P.; Mahoney, M. W.; Fuller, C. B.

2006-02-01

43

Europa's `Mitten': Estimate of Ice Thickness Using an Elastic Plate Model  

NASA Astrophysics Data System (ADS)

Results of a 2-D elastic plate model used to estimate the thickness of ice below Europa's 'mitten' are presented. Using properties of polycrystalline water ice and inferred Europan 'cryomagma', we calculate an elastic thickness of ~2.1-2.6 km.

Chuang, F. C.; Figueredo, P. H.; Kirk, R. L.; Greeley, R.

2001-03-01

44

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

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

45

Crack growth and fracture of thick 5083-O plate under liquefied natural gas ship spectrum loading  

Microsoft Academic Search

Data are presented on the growth rate of surface flaws and through cracks in thick aluminum alloy 5083-O plate for spherical liquefied natural gas (LNG) cargo tanks. Tests were made using 135-mm (5.3-in.) thick specimens loaded so as to simulate the bending and membrane stresses in the equatorial ring and 43-mm (1³\\/-in.) thick specimens loaded to simulate the membrane stresses

R. A. Kelsey; R. H. Wygonik; P. Tenge

1975-01-01

46

Thickness measurement of transparent glass plates using a lateral shearing cyclic path optical configuration setup and polarization phase shifting interferometry  

SciTech Connect

We present a measurement technique to determine the thickness of a transparent glass plate (GP) by using a lateral shearing cyclic path optical configuration (CPOC) setup and polarization phase shifting interferometry (PPSI). In the technique, the GP introduces a longitudinal shift in the focus of the beam and, as a result, a spherical wavefront emerges from the lens, which is otherwise set for producing a collimated beam. Using CPOC, two laterally sheared orthogonally polarized beams are generated from the incident spherical wavefront. By applying PPSI, the slope of the optical path difference variation between the laterally sheared interfering beams is evaluated, and the radius of the spherical wavefront and the longitudinal shift of the beam focus are calculated. The thickness of the GP is determined from the standard relation between the longitudinal shift of the focus introduced by the GP and the thickness of the GP. Results obtained for a GP of 9.810mm thickness are presented.

Kumar, Y. Pavan; Chatterjee, Sanjib

2010-11-20

47

Propagating plane harmonic waves through finite length plates of variable thickness using finite element techniques  

NASA Technical Reports Server (NTRS)

An analysis is given using finite element techniques which addresses the propagaton of a uniform incident pressure wave through a finite diameter axisymmetric tapered plate immersed in a fluid. The approach utilized in developing a finite element solution to this problem is based upon a technique for axisymmetric fluid structure interaction problems. The problem addressed is that of a 10 inch diameter axisymmetric fixed plate totally immersed in a fluid. The plate increases in thickness from approximately 0.01 inches thick at the center to 0.421 inches thick at a radius of 5 inches. Against each face of the tapered plate a cylindrical fluid volume was represented extending five wavelengths off the plate in the axial direction. The outer boundary of the fluid and plate regions were represented as a rigid encasement cylinder as was nearly the case in the physical problem. The primary objective of the analysis is to determine the form of the transmitted pressure distribution on the downstream side of the plate.

Clark, J. H.; Kalinowski, A. J.; Wagner, C. A.

1983-01-01

48

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

E-print Network

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

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

2014-01-13

49

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

E-print Network

June 2008) We consider the deposition of a film of viscous liquid on a flat plate being withdrawn from a bath, experimentally and theoretically. For any plate speed U, there is a range of ``thick'' filmThick Films of Viscous Fluid Coating a Plate Withdrawn from a Liquid Reservoir J. H. Snoeijer,1 J

50

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

51

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

52

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

53

Thickness-shear vibration analysis of rectangular quartz plates by a differential quadrature finite element method  

NASA Astrophysics Data System (ADS)

Thickness-shear vibration of quartz plates is characterized by high frequency vibration that needs high accuracy and huge computational cost. In this paper, a differential quadrature finite element method (DQFEM) is applied to thickness-shear vibration of a rectangular quartz plate. The DQFEM is an effective means of implementing the p-version finite element method that is capable of providing highly accurate results using a few grid points. The fundamental thickness-shear modes obtained by the DQFEM are compared with those in literature, which validates the correctness of the results. The fundamental thickness-shear mode of the DQFEM could satisfy the completely free boundary conditions very well, so the accuracy of the DQFEM results are much better than those obtained recently in literature that could not satisfy the boundary conditions very well.

Liu, Bo; Xing, Yufeng

2014-10-01

54

Engineering Design Data for Aluminum Alloy 2124-T851 Thick Plate.  

National Technical Information Service (NTIS)

Tensile, fracture, fatigue, fatigue crack growth, and stress corrosion properties for aluminum alloy 2124-T851 thick plate were determined. Material property comparisons were then drawn between the 2124-T851 alloy and its parent alloy, 2024, in the T851 c...

K. A. Fudge, R. E. Jones

1974-01-01

55

Plate thickness and transducer distance dual inversion with dry contact ultrasonic Lamb wave transducers  

Microsoft Academic Search

Ultrasonic Lamb wave techniques are widely used in a number of NDE applications. Recent development in dry contact Lamb wave transducers enables one to efficiently excite Lamb waves without the aid of liquid couplant. However, in order to perform thickness measurement in a plate-like structures, the transducer to transducer distance has to be fixed and known to a good accuracy,

J. Pei; B. T. Khuri-Yakub

1997-01-01

56

Microstructure and pitting corrosion of friction stir welded joints in 2219-O aluminum alloy thick plate  

Microsoft Academic Search

Effect of welding parameters on the microstructure and pitting corrosion of different positions along the thickness of weld nugget zone in friction stir welded 2219-O aluminum alloy plate was investigated using scanning electron microscopy (SEM), polarization experiment and electrochemical impedance tests (EIS). It was found that the material presents significant passivation and the top has best corrosion resistance compared to

Weifeng Xu; Jinhe Liu

2009-01-01

57

Pitting corrosion of friction stir welded aluminum alloy thick plate in alkaline chloride solution  

Microsoft Academic Search

The pitting corrosion of different positions (Top, Middle and Bottom) of weld nugget zone (WNZ) along thickness plate in friction stir welded 2219-O aluminum alloy in alkaline chloride solution was investigated by using open circuit potential, cyclic polarization, scanning electron microscopy and atomic force microscope. The results indicate that the material presents significant passivation, the top has highest corrosion potential,

Weifeng Xu; Jinhe Liu; Hongqiang Zhu

2010-01-01

58

Finite Element Analysis of Nonlinear Thickness-shear Vibrations of AT-cut Quartz Crystal Plates  

E-print Network

Finite Element Analysis of Nonlinear Thickness-shear Vibrations of AT-cut Quartz Crystal Plates Ji, dujianke}@nbu.edu.cn Abstract--The nonlinear finite element analysis is performed with the nonlinear a smaller size in comparison with the 3D approach. General procedure of nonlinear finite element analysis

Wang, Ji

59

Aluminum-Copper-Lithium Alloy 2050 Developed for Medium to Thick Plate  

NASA Astrophysics Data System (ADS)

This article discusses Al-Cu-Li 2050 alloy developed, qualified, and produced by Alcan Aerospace as plates. AA2050 alloy offers a low density high corrosion resistant alternative to incumbent medium to thick plate alloys like 7050-T7451, and to thin plate alloys like 2024 or higher damage tolerant versions. The fundamentals behind the choice of the Al-Cu-Li chemistry are highlighted, as well as the property balance generated in a wide range of thickness from 12 to 127 mm (0.5 to 5 in.). Manufacturing behavior of the alloy when machining or friction stir welding is also discussed in detail. Finally, it is shown that the appropriate recycling investments and logistics permit the use of 2050 alloy at an acceptable level of extra cost per kilo saved, when weight benefits are taken into account.

Lequeu, Ph.; Smith, K. P.; Danilou, A.

2010-08-01

60

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

61

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

SciTech Connect

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

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

2010-02-01

62

Calculation of diffraction efficiencies of a grating made on a thick transparent plate  

NASA Astrophysics Data System (ADS)

Mathematical formulas are derived for predicting diffraction efficiencies of a grating made on a thick transparent parallel plate (substrate) or cemented between two plates. The formulas are applicable in two situations: (1) when the coherence length of the light source is greater than the thickness of the grating but less than that of the substrate; (2) when the thickness of the substrate is not precisely known, therefore only the average values of the diffraction efficiencies can be expected. There is no limitation on the number of propagating diffraction orders that are present in the system. The derivation uses the concept of energy scattering matrix, therefore it is simpler than a previous method that yielded limited results.

Li, Lifeng

1999-02-01

63

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

E-print Network

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

Beuthe, Mikael

2007-01-01

64

Active sound radiation control of a thick piezolaminated smart rectangular plate  

NASA Astrophysics Data System (ADS)

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.

Hasheminejad, Seyyed M.; Keshavarzpour, Hemad

2013-09-01

65

Influence of piezoceramic to fused silica plate thickness on the radii of curvature of piezoelectric bimorph mirror  

SciTech Connect

Piezoelectric based bimorph mirrors (PBM) find extensive use in focusing of x-ray beams. Many optical instruments require use of PBM whose radii of curvature can be tuned precisely. The 100 mm and 300 mm PBMs were fabricated with varying piezoelectric to fused silica plate thicknesses. The radii of curvature of free standing mirrors were measured as a function of voltage and it was found to decrease with increasing voltage. For a given piezoelectric plate thickness, as the fused silica thickness increases, the radii of curvature was found to increase owing to increase in stiffness of the mirror. On the other hand, for a given fused silica plate thickness, when the piezoelectric plate thickness is increased, the radii of curvature are decreased for a given electric field, due to increase in generated force. This study brings out the influence of piezoceramic to fused silica plate thickness on the radii of curvature of PBM.

Libu, M.; Susanth, S.; Vasanthakumari, K. G.; Dileep Kumar, C. J.; Raghu, N. [Centre for Materials for Electronics Technology (C-MET), Shoranur Road, M. G. Kavu P.O., Thrissur 680 581 (India)

2012-01-15

66

Testing Plate Reconstructions For The High Arctic Using Crustal Thickness Mapping From Gravity Inversion  

NASA Astrophysics Data System (ADS)

The plate tectonic history of the Amerasia Basin (High Arctic) and its distribution of oceanic and continental lithosphere is poorly known. A new method of gravity inversion with an embedded lithosphere thermal gravity anomaly correction has been applied to the NGA (U) Arctic Gravity Project data to predict crustal thickness and to test different plate reconstructions within the Arctic region. Two end member plate reconstruction models have been tested: in one model the Mendeleev Ridge is rifted from the Canadian margin while in the other it is rifted from the Lomonosov Ridge. The inversion of gravity data to map crustal thickness variation within oceanic and rifted continental margin lithosphere requires the incorporation of a lithosphere thermal gravity anomaly correction for both oceanic and continental lithosphere. Oceanic lithosphere and stretched continental margin lithosphere produce a large negative residual thermal gravity anomaly (up to -380 mGal), for which a correction must be made in order to determine realistic Moho depth by gravity anomaly inversion. The lithosphere thermal model used to predict the lithosphere thermal gravity anomaly correction may be conditioned using plate reconstruction models to provide the age and location of oceanic lithosphere. Two end- member plate reconstruction models have been constructed for the opening of the Amerasia Basin and used to determine lithosphere thermal gravity anomaly corrections: in one model the (presumably) continental Mendeleev Ridge is rifted from the Canadian margin in the Jurassic while in the other it is rifted off the Lomonosov Ridge (Eurasia Basin) in the Late-Cretaceous. Crustal thickness predicted by gravity anomaly inversion for the two plate reconstructions is significantly different in the Makarov Basin because of their different lithosphere thermal gravity corrections. The plate reconstruction with younger Makarov Basin ages gives a crustal thickness of the order 6-8 km thinner than the older Makarov Basin model. A crustal thickness of approximately 20 km has been obtained from seismic refraction data (Lebedeva-Ivanova et al., 2006) which would imply a Late Mid-Cretaceous age for the Makarov Basin. In this case plume-related forces may have contributed to the opening of this basin, as regional plate tectonics predict compression and not extension in the Makarov Basin area at this time.

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

2006-12-01

67

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

PubMed Central

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

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

2014-01-01

68

The Plate Paradigm; the Standard Model Reductio ~ ad ~Absurdum  

NASA Astrophysics Data System (ADS)

Midplate volcanism, volcanic chains, diffuse boundaries and variable chemistry basalts are usually considered to be outside the plate tectonic hypothesis and to need separate explanations. This is true only for the instantaneous, steady state, kinematic and hard plate versions of the hypothesis. In the more general plate paradigm (with fewer restrictive adjectives), melting `anomalies', seamount chains, and LIPs are by-products of plate tectonics. This assumes that the shallow mantle is close to the (variable) melting point and that athermal and episodic processes are important. Cooling of the surface generates forces that drive, break and reorganize plates; global reorganizations (including new plate boundaries) are intrinsic; regions of intense, long-lived magmatism and shallow tensile stress are (usually but not always) plate boundaries. Plates are regions of lateral compression. Plate boundaries have shallow extensional or strike-slip earthquakes; where the mantle is near the melting point the buoyancy of magma generates dikes and volcanoes. When compressional forces dominate, upwelling magmas pond beneath the plate until released by extensional stresses. Large melting anomalies are episodic and associated with changes in plate stress and new plate boundaries (often triple-junctions). Incipient boundaries can be extensional and volcanic, as can abandoned ones. Ridges, island arcs, seamount fields and chains, and reactivated and incipient boundaries, are part of a single process. The plate paradigm thereby reverses the assumptions of current geodynamic and geochemical reservoir models : Locations of volcanoes are controlled by lithospheric stress and fabric ( not mantle temperature ).The volumes of magma are controlled by lithospheric extension and shallow mantle fertility (not by conditions at the core mantle boundary).The stress-, fertility- and thermal-states are controlled by plate tectonics and upper mantle recycling (not by infusions from the deep mantle).The upper mantle has variable chemistry, melting point, potential temperature and is perisolidus everywhere ( not just under hotspots). The upper mantle is not dry, refractory, isothermal, uniform, or well-stirred . The ends of volcanic chains are not `fixed' . One even reverses the motivating question, why are there not volcanoes everywhere (instead of why are there volcanoes some places)? Non-fixity, aberrant ages and directions, absence of uplift and thermal rejuvenation, low heat flow, `normal' magma temperatures, distributed volcanism, and seamount chemistry are not `anomalies' as they are in hotspot theory. The associations of LIPs with suture belts and cratons are no longer coincidences. Predictions: Midplate volcanism implies extensional stress, not necessarily high heat flow, uplift or thermally thinned plate. It need not be age-progressive, parallel or in chains. Basalts are variable in chemistry (central limit theorem) and involve the same recycled components . Recycled oceanic crust and gabbro cumulates are variably distributed in the shallow mantle . The scale of chemical heterogeneity corresponds to the scale of recycled components (crust, sediments, lithosphere) and arc segments. Volcanic chains are stress gages, not motion detectors. If the shallow mantle is perisolidus (near the melting point) then even the deepest slowest ridges will be magmatic; melting will occur under thick plates (not likely in thermal theories). Ponding and underplating should be common. In contrast to thermal theories, volcanism can initiate and terminate abruptly. The technique of testing a hypothesis by assuming the opposite, is {reductio~ ad ~absurdum}. A simpler more powerful theory emerges when we drop the adjectives and reverse the assumptions.

Anderson, D. L.

2003-12-01

69

Effect of Initial Stress on a Fiber-Reinforced Anisotropic Thermoelastic Thick Plate  

NASA Astrophysics Data System (ADS)

The two-dimensional problem of generalized thermoelasticity for a fiber-reinforced anisotropic thick plate under initial stress is studied in the context of the Lord and Shulman theory. The upper surface of the plate is thermally insulated with prescribed surface loading while the lower surface of the plate rests on a rigid foundation and temperature. The problem is solved numerically using a finite element method. Numerical results for the temperature distribution, and the displacement and stress components are given and illustrated graphically. It is found from the graphs that the initial stress significantly influences the variations of field quantities. The results obtained in this paper may offer a theoretical basis and meaningful suggestions for the design of various fiber-reinforced anisotropic thermoelastic elements under loading to meet special engineering requirements.

Abbas, Ibrahim A.; Abd-alla, Abo-el-nour N.

2011-05-01

70

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

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

71

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

NASA Technical Reports Server (NTRS)

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.

Roth, Don J.

1996-01-01

72

Preparation of Lead Zirconate Titanate Thick Films by Arc-Discharged Reactive Ion-Plating Method  

NASA Astrophysics Data System (ADS)

Lead zirconate titanate (PZT) thick films of 1 to 3 ?m thickness were prepared by an arc-discharged reactive ion-plating (ADRIP) method. Each PZT thick film had a columnar dense structure. The films showed a perovskite single phase without any thermal treatment after deposition. A high plasma density of the arc discharge enabled a high deposition rate of more than 3 ?m/h. The relative dielectric constant (\\varepsilonr) of the PZT thick films with the Zr/Ti=53/47 composition was about 2000. This value was almost equivalent to that of PZT bulk ceramics. The films typically showed well-saturated P-E hysteresis curves with the remanent polarization (Pr) of 44 ?C/cm2 and the coercive field (Ec) of 39 kV/cm. The butterfly-shaped property of the displacement curve, which is caused by the bending motion in the vertical direction on the film surface, was also observed. Furthermore, the PZT thick films with the (100)-dominant orientation could be obtained by depositing them onto (100)-preferred PZT thin layers which were prepared by a chemical solution deposition (CSD) process.

Yasuda, Yoshiaki; Akamatsu, Masahiro; Tani, Masanao; Yoshida, Makoto; Kondo, Ken-ichi; Iijima, Takashi

2001-09-01

73

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

NASA Astrophysics Data System (ADS)

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.

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

74

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

NASA Technical Reports Server (NTRS)

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.

Powell, W. B.

1973-01-01

75

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

PubMed

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

Miks, Antonin; Novak, Jiri; Novak, Pavel

2010-06-10

76

Simple method for plating Escherichia coli bacteriophages forming very small plaques or no plaques under standard conditions.  

PubMed

The use of low concentrations (optimally 2.5 to 3.5 microg/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 after induction of prophages present in six E. coli O157:H(-) strains which did not form plaques when standard plating procedures were employed. PMID:18586961

Lo?, Joanna M; Golec, Piotr; Wegrzyn, Grzegorz; Wegrzyn, Alicja; Lo?, Marcin

2008-08-01

77

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

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

78

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

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

79

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

NASA Astrophysics Data System (ADS)

Laser-assisted stir welding is a hybrid process that combines energy from a laser with functional heating and mechanical energy to join materials in the solid state. The technology is an adaptation of friction stir welding which is particularly suited for joining thick plates. Aluminum plates up to 75 mm thick have been successfully joined using friction stir welding. Since joining occurs in the solid state, stir technology offers the capability for fabricating full penetration joints in thick plates with better mechanical properties and less weld distortion than is possible by fusion processes. Currently friction stir welding is being used in several industries to improve productivity, reduce weight, and increase the strength of welded structures. Examples include: (a) the aircraft/aerospace industry where stir technology is currently being used to fabricate the space shuttle's external tank as well as components of the Delta family of rockets; (b) the shipping industry where container manufacturers are using stir technology to produce lighter containers with more payload capacity; and (c) the oil industry where offshore platform manufactures are using automated stir welding plants to fabricate large panels and structures up to 16 meters long with widths as required. In all these cases, stir technology has been restricted to aluminum alloys; however, stainless and HSLA 65 steels have been recently stir welded with friction as the primary heat source. One of the difficulties in adapting stir welding to steel is tool wear aggravated by the high tool rubbing velocities needed to provide frictional heat input into the material. Early work showed that the tool shoulder reached temperatures above 1000 C and the weld seam behind the tool stayed within this temperature range for up to 25 mm behind the tool. Cross sections of stir welded samples showed that the heat-affected zone is relatively wide and follows the profile of the tool shoulder. Besides minimizing the tool wear by increasing the energy into the material, another benefit of the proposed Laser Assisted Stir Welding (LASW is to reduce the width of the heat affected zone which typically has the lowest hardness in the weld region. Additionally, thermal modeling of the friction stir process shows that the heat input is asymmetric and suggests that the degree of asymmetry could improve the efficiency of the process. These asymmetries occur because the leading edge of the tool supplies heat to cold material while the trailing edge provides heat to material already preheated by the leading edge. As a result, flow stresses on the advancing side of the joint are lower than corresponding values on the retreating side. The proposed LASW process enhances these asymmetries by providing directional heating to increase the differential in flow stress across the joint and improve the stir tool efficiency. Theoretically the LASW process can provide the energy input to allow the flow stresses on the advancing side to approach zero and the stir efficiency to approach 100 percent. Reducing the flow stresses on the advancing side of the weld creates the greatest pressure differential across the stir weld and eliminates the possibility of voids on the advancing side of the joint. Small pressure differentials result in poor stir welds because voids on the advancing side are not filled by the plastic flow of material from the retreating side.

Williamson, Keith M.

2002-12-01

80

A Comparison of Closed-Form and Finite-Element Solutions of Thick, Laminated, Anisotropic Rectangular Plates.  

National Technical Information Service (NTIS)

In this study the effects of reduced integration, mesh size, and element type (i.e. linear or quadratic) on the accuracy of a penalty finite element based on the theory governing thick, laminated, anisotropic composite plates, are investigated. In order t...

J. N. Reddy

1979-01-01

81

Cryogenic fracture toughness and temperature rise of thick section weldments in forged JJ1 type austenitic stainless steel plate  

Microsoft Academic Search

JJ1 type austenitic stainless steel is emerging as the preferred structural material for nuclear fusion reactor superconducting magnet casings designed to operate at the temperature of liquid helium (4 K). To evaluate the cryogenic fracture toughness and temperature rise of tungsten inert gas (TIG) welds in 200 mm thick forged JJ1 type austenitic stainless steel plate for the next generation

Y. Shindo; T. Takahashi; K. Horiguchi; K. Sanada; T. Kobori

1998-01-01

82

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

83

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

E-print Network

Craphy. 52 55 66 FIG LTiES Page 1. Flow Diagram of &&uipment 2. Photograph of the "ouipmvnt 10 Sketch of Perforated Plate with i!achined Insert . . 4. Typioal Supportinq and Recov"ry Volocitl' Curves for a 15 Perforation Disaster Study 22 5.... Supporting Velocity versus Liquid Iiei'ht by Dif. eront Definitions. 6A. Supporting Velocity versus Perforation ziamoter with Four Inohes of Water on the Plate 27 63. Supportin. Velocity versus Perforation Diameter with o. ' Inches oi' iqater on *he...

Cottle, John Ernest

2012-06-07

84

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

Federal Register 2010, 2011, 2012, 2013

...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...

2013-10-23

85

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

Federal Register 2010, 2011, 2012, 2013

...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...

2013-10-23

86

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

NASA Astrophysics Data System (ADS)

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.

Lpez-Vzquez, J. Carlos; Den-Ben, X. Lus; Trillo, Cristina; Doval, ngel F.; Fernndez, Jos L.; Amlani, Faisal; Bruno, Oscar P.

2010-09-01

87

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

88

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

89

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

SciTech Connect

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.

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

90

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

PubMed

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

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

2012-09-01

91

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

Microsoft Academic Search

An overview of seismic, thermal, and petrological evidence on the structure of Precambrian lithosphere suggests that its local maximum thickness is highly variable (140350 km), with a bimodal distribution for Archean cratons (200220 km and 300350 km). We discuss the origin of such large differences in lithospheric thickness, and propose that the lithospheric base can have large depth variations over

Irina M. Artemieva; Walter D. Mooney

2002-01-01

92

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

E-print Network

(ZnO) both belong to crystals of 6 mm symmetry. Thin AlN and ZnO plates are of current and growing research interest because of the development of thin film bulk acoustic wave resonators (FBAR), e.g., [1. This fact also needs to be included in the analysis for an accurate description of a thin film resonator

Wang, Ji

93

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

94

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

Federal Register 2010, 2011, 2012, 2013

...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...

2012-12-31

95

Rate effects of standard and high-strip-current microchannel plate image intensifiers  

Microsoft Academic Search

The gains of gated MCPIIs at high repetition rate (up to 10 kHz) were measured. Comparisons were made between the gain behavior of a standard ITT type F4111 MCPII and similar device incorporating a high strip current microchannel plate. The most notable effect observed for the standard MCPII is a decline in luminous gain with increasing gate repetition rate and

George J. Yates; Kevin L. Albright; Paul A. Zagarino; Matthew C. Thomas

1992-01-01

96

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

97

Thick Plate Rollinga Numerical Approach in Comparison with Analytics and Experimental Data  

NASA Astrophysics Data System (ADS)

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.

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

2011-05-01

98

Effects of specimen thickness and side-groove on fracture toughness of JN1 austenitic stainless steel rolled plate at liquid helium temperature  

SciTech Connect

In order to evaluate the fracture toughness (J{sub IC}) of JN1 austenitic stainless steel rolled plate, we performed elastic-plastic fracture toughness tests with standard and modified compact tension specimens at liquid helium temperature. These tests were conducted in accordance with ASTM standards E813-81 and E813-87 for determining J{sub IC} using the unloading compliance method to monitor crack growth. The effects of specimen thickness and side-groove on J{sub IC} and tearing modulus (T{sub mat}) are reported. The final value of physical crack extension was taken as the average of nine measurements using an optical microscope. Fracture surfaces were examined by scanning electron microscopy (SEM) to verify the failure mechanisms. The effects of crack tunneling on the determination of J-integral resistance curves and valid J{sub IC} values, and a difference between ASTM standards E813-81 and E813-87 are also discussed.

Shindo, Y.; Horiguchi, K.; Kobori, T. [Tohoku Univ., Sendai (Japan)] [and others

1997-06-01

99

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

Federal Register 2010, 2011, 2012, 2013

...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...

2013-11-01

100

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

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

101

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

PubMed

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

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

2014-09-01

102

Enumeration and characterization of standard plate count bacteria in chlorinated and raw water supplies.  

PubMed Central

Nearly 700 standard plate count (SPC) bacteria were isolated from drinking water and untreated surface water and identified according to a scheme developed to permit the rapid, simple classification of microorganisms to genus, species, or group. Actinomycetes and Aeromonas species were the two most common groups of SPC bacteria in chlorinated distribution water. Aeromonas spp. and Enterobacter agglomerans were the two most common groups of SPC bacteria in raw water. Identification of bacterial populations before and after contact with chlorine (1 to 2 mg/liter) for 1 h revealed that chlorination selected for gram-positive bacteria. Water that contained high densities of bacteria known to be antagonistic to coliforms had low coliform isolation rates. The membrane filtration technique for enumerating SPC bacteria recovered significantly higher numbers (P < 0.001) than the standard pour plate technique. PMID:7447444

LeChevallier, M W; Seidler, R J; Evans, T M

1980-01-01

103

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

Microsoft Academic Search

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

Y. Sato; K. Nishimura

2006-01-01

104

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

SciTech Connect

Low resistivity Ga-doped ZnO films were prepared on a glass substrate by ion plating with direct current arc discharge. Thickness dependent changes in the electrical properties of the films are reported, focusing on the thin films of less than 100 nm thickness. Structural analyses showed that the thinnest film of 30 nm thickness consists of well-oriented columnar grains normal to the substrate, and the resistivity was as low as 4.4x10{sup -4} {omega} cm. The changes in lattice strain and c-axis fluctuation with the growth of grains are also shown to be associated with the electrical properties.

Yamada, Takahiro; Miyake, Aki; Kishimoto, Seiichi; Makino, Hisao; Yamamoto, Naoki; Yamamoto, Tetsuya [Kochi University of Technology, 185, Miyanokuchi, Tosayamada, Kami, Kochi 782-8502 (Japan)

2007-07-30

105

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

106

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

NASA Astrophysics Data System (ADS)

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 and computes the output charge of the PVDF gauge itself is used instead of the usual charge mode which measures the charge of the output capacity. (3) The phase velocity associated with stress passing through a metallic target specimen is determined by considering the phase velocity of stress across the in-material gauge, e.g., the manganin or PVDF gauge sandwiched between the laminated target specimens.

Sato, Y.; Nishimura, K.

2006-08-01

107

Prospective randomized study of transurethral vaporization resection of the prostate using the thick loop and standard transurethral prostatectomy  

Microsoft Academic Search

Objectives. Transurethral vaporization resection of the prostate (TUVRP) is a recent modification of the standard transurethral prostatectomy (TURP). The procedure uses one of the novel, thick resection loops coupled to augmented electrocutting energy. We evaluated the safety and efficacy of TUVRP in comparison with TURP.Methods. Sixty-eight patients with prostatic outflow obstruction were prospectively randomized between equal TUVRP and TURP treatment

Abdul-Moniem El Tiraifi; Salah R El Faqih; Salah H Hassan; Ramiz A Attassi; Rabie E Abdel-Halim

2000-01-01

108

Comparative Evaluation of TLC and HPTLC Plates Containing Standard and Enhanced UV Indicators for Efficiency, Resolution, Detection, and Densitometric Quantification Using Fluorescence Quenching  

Microsoft Academic Search

Thin layer chromatography (TLC) and high performance TLC (HPTLC) commercially precoated silica gel plates, with enhanced brightness ultraviolet (UV)?indicator, were compared with comparable plates formulated with standard indicators. Caffeine, acetaminophen, and salicylamide were used as the model test compounds. Results showed that the increased UV?indicator plates had visually brighter backgrounds, however, the limits of detection (LOD) did not improve. Differences

Caitlin Sullivan; Joseph Sherma

2005-01-01

109

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

E-print Network

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.

R. Y. Chiao

2010-11-14

110

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

NASA Astrophysics Data System (ADS)

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

Bird, P.; Kagan, Y. Y.

2003-12-01

111

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

SciTech Connect

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

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

1991-07-01

112

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

E-print Network

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

American Society for Testing and Materials. Philadelphia

2010-01-01

113

Secondary Electron Yield of Emissive Materials for Large-Area Micro-Channel Plate Detectors: Surface Composition and Film Thickness Dependencies  

NASA Astrophysics Data System (ADS)

The ongoing development of Atomic Layer Deposition (ALD) enables the use of relatively inexpensive and robust borosilicate micro-channel substrates for use as Micro-Channel Plates (MCPs). The surfaces of the channels in these glass plates are functionalized to control the conductivity as well as the Secondary Electron Yield (SEY). The extensive SEY data found in literature show significant variation for a given material depending on the apparatus, the measurement procedure, and the sample preparation and handling. We present systematic studies on the effects of film thickness and surface chemical composition on SEY. We have modified an existing ultra-high vacuum apparatus containing X-ray and Ultraviolet Photoelectron Spectrometers (XPS and UPS, respectively) by adding a modified Low Energy Electron Diffraction (LEED) module for SEY measurements. With these tools, we have characterized the secondary electron emissive properties for MgO, Al2O3, and multilayered MgO/TiO2 structures to serve as electron emissive layers in the channels of the MCPs.

Jokela, Slade J.; Veryovkin, Igor V.; Zinovev, Alexander V.; Elam, Jeffrey W.; Mane, Anil U.; Peng, Qing; Insepov, Z.; Large Area Picosecond Photodetector Collaborationd

114

Practical Bench Comparison of BBL CHROMagar Orientation and Standard Two-Plate Media for Urine Cultures  

Microsoft Academic Search

A total of 1,023 urine samples sent for routine culture were plated onto sheep blood and MacConkey agars and a BBL CHROMagar Orientation (CO; Becton Dickinson, Cockeysville, Md.) plate, and the results were compared. Of these, 250 urine samples (24%) grew >10,000 CFU of one or two putative pathogens\\/ml and 773 showed no growth (NG), mixed growth of <10,000 CFU\\/ml,

Holly A. D'Souza; Mary Campbell; Ellen Jo Baron

2004-01-01

115

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

E-print Network

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...

American Society for Testing and Materials. Philadelphia

2010-01-01

116

Angular shear plate  

Microsoft Academic Search

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

Mitchell C. Ruda; Alan W. Greynolds; Tilman W. Stuhlinger

2009-01-01

117

Plate Tectonics  

NSDL National Science Digital Library

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.

National Science Teachers Association (NSTA)

2007-03-21

118

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

NASA Technical Reports Server (NTRS)

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.

Simon, F.

1975-01-01

119

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

PubMed Central

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 525.9034.08 m, 525.9234.10 m, 530.3035.62 m, and 543.5037.11 m 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 -0.056.77 m (13.3/-13.3) between SD-OCT and Scheimpflug-Placido topographer, 4.383.79 m (11.8/-3.1) between OLCR and SD-OCT, 4.386.03 m (16.2/-7.5) between OLCR and Scheimpflug-Placido topographer, 13.206.46 m (25.9/0.5) between USP and OLCR, 17.596.76 m (30.8/4.3) between USP and SD-OCT, and 17.588.13 m (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

Bayhan, Hasan Ali; Aslan Bayhan, Seray; Can, Izzet

2014-01-01

120

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)

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.

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

2014-06-01

121

Comparison of Limulus assay, standard plate count, and total coliform count for microbiological assessment of renovated wastewater.  

PubMed Central

The Limulus endotoxin assay was compared to the standard plate count and total coliform count for assessment of the bacteriological quality of reclaimed wastewater. A total of 48 water samples from an advanced waste treatment plant in Dallas, Tex. were examined by the three techniques. Limulus assays were technically simpler to perform and provided results much sooner than conventional culture methods. However, the endotoxin values did not correlate extremely well with determinations of viable bacterial numbers. This lack of correlation may have been due to alterations in the normal ratio of viable gram-negative cells to endotoxin caused by water reclamation procedures. PMID:384901

Jorgensen, J H; Lee, J C; Alexander, G A; Wolf, H W

1979-01-01

122

Chromium ion plating studies for enhancement of bearing lifetime  

NASA Technical Reports Server (NTRS)

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).

Davis, J. H.

1982-01-01

123

The prevalence of some mastitis pathogens in bulk milk of Dutch dairy goats and the relationship with bulk milk somatic cell count and bulk milk standard plate count  

Microsoft Academic Search

The aim of this study was to assess the correlation of bulk milk somatic cell count (BMSCC) with bulk milk standard plate count (BMSPC) and with the number of coliform bacteria, coagulase negative staphylococci (CNS) and S. aureus . We also described the prevalence of these pathogens in bulk milk of Dutch dairy goat farms. In total 53 dairy goat

N. Dik; G. Koop; L. Lipman

124

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)

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.

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

2013-03-01

125

Beyond Plate Tectonics: Plate Dynamics  

E-print Network

Plate tectonics dogma has resulted in a variety of theories that frequently violate first principles. In this article it is suggested that ridges are in compression, not tension from convection cells, triple junctions cause hot spots (not vice versa), mantle plumes do not cause hot spot tracks, chord push creates pressures well in excess of lithostatic load, the arch effect demonstrates that rifts form both in compression and tension, surging (i.e. the sudden and rapid motion of the plates) occurs episodically, the presence of a basal shear zone a few meters thick during surging, the preferred initiation of subduction zones at the ridge, revision of the Wilson Cycle, the conformance of old school geologists and plate tectonicians, earth-based non bolide impact mass extinctions, the loss of the earths magnetic field and its subsequent reappearance, additional application of the least work (or maximum

Richard Moody

126

Hypervelocity plate acceleration  

SciTech Connect

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.

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

1991-01-01

127

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

NASA Technical Reports Server (NTRS)

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.

Johnson, S. M.

1976-01-01

128

Channel plate for DNA sequencing  

DOEpatents

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.

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

1998-01-01

129

Channel plate for DNA sequencing  

DOEpatents

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.

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

1998-01-13

130

Thru-thickness bending stress distribution at elevated temperatures  

E-print Network

the extreme fiber strains exceeded ten percent, which further adds to the increased risk of the flange plate cracking during fabrication. The highest residual stresses through the plate??s thickness occurred during cold bending. The residual stresses through...

Christian, Lee Conner

2005-08-29

131

Development of methods for estimating the Z properties of thick rolled products  

NASA Astrophysics Data System (ADS)

The main stages of developing the methods for estimating the mechanical properties of rolled plates across the plate thickness ( Z properties) and the corresponding standards are described in a chronological manner. The application of experimental fracture mechanics methods for estimating the sensitivity of building steels to laminated fracture is discussed. The effects of the structure dispersity, the steel purity in non-metallic inclusions, and the reduction on the Z properties of rolled products are described.

Odesskii, P. D.; Egorova, A. A.

2010-10-01

132

Standard reference radiographs for steel fusion welds  

E-print Network

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

American Society for Testing and Materials. Philadelphia

2011-01-01

133

Overriding plate controls on subduction evolution  

NASA Astrophysics Data System (ADS)

Geologic and geophysical observations indicate that the thickness, density, and strength of the lithosphere vary on the Earth. However, the role of the overriding plate lithosphere properties on the evolution and morphology of subduction is not well understood. This paper presents time-dependent numerical models of subduction that vary the overriding plate thickness, strength, and density and allow for a plate interface that evolves with time via an anisotropic brittle failure rheology. We examine the effect of these parameters on subduction evolution, in particular, the emergence of (a) asymmetric versus symmetric subduction, (b) trench retreat versus advance, (c) subduction zone geometry, (d) slab stagnation versus penetration into the lower mantle, and (e) flat slab subduction. Almost all of the models presented result in sustained asymmetric subduction from initiation. Trench advance occurs in models with a thick and or strong overriding plate. Slab dip, measured at a depth below the plate boundary interface, has a negative correlation with an increase in overriding plate thickness. Overriding plate thickness exerts a first-order control over slab penetration into the lower mantle, with penetration most commonly occurring in models with a thick overriding plate. Periods of flat slab subduction occur with thick, strong overriding plates producing strong plate boundary interface coupling. The results provide insight into how the overriding plate plays a role in establishing advancing and retreating subduction as well as providing an explanation for the variation of slab geometry across subduction zones on Earth, where similar patterns of evolution are observed.

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

2014-08-01

134

>.........standard  

E-print Network

, develop software to implement them, test such techniques against the state of the art. #12;. ......... IETF standard protocols Collaborators / Customers Standards Groups: MPEG, SMPTE NIST Collaborators: ATP Other Collaborators: Academic

135

Plate Tectonics  

NSDL National Science Digital Library

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 ...

Rohlfing, Mrs.

2011-02-03

136

Plate Tectonics  

NSDL National Science Digital Library

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 ...

Walls, Mrs.

2011-01-30

137

Plate Tectonics  

NSDL National Science Digital Library

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.

Smoothstone; Company, Houghton M.

138

Plates with incompatible prestrain  

E-print Network

We study the effective elastic behavior of incompatibly prestrained plates, where the prestrain is independent of thickness as well as uniform through the thickness. We model such plates as three-dimensional elastic bodies with a prescribed pointwise stress-free state characterized by a Riemannian metric $G$ with the above properties, and seek the limiting behavior as the thickness goes to zero. Our results extand the prior analysis in M. Lewicka, M. R. Pakzad ESAIM Control Optim. Calc. Var. 17 (2011), no. 4. We first establish that the $\\Gamma$-limit is a Kirchhoff type bending. Further, we show that the minimum energy configuration contains non-trivial Kirchhoff type bending -- i.e., the scaling of the three-dimensional energy is of the order of the cube of the plate thickness -- if and only if the Riemann curvatures $R^3_{112}, R^3_{221}$ and $ R_{1212}$ of $G$ do not identically vanish. We demonstrate through examples, the existence of a new regime where the three above curvatures of $G$ vanish (while the mid-plane of the plate may or may not be flat), but the limiting configuration still has energy that is of the order of F\\"oppl - von K\\'arm\\'an plates. Finally, we apply these results to a model of nematic glass, including a characterization of the condition when the metric is immersible, for $G=\\mbox{Id}_3 +\\gamma\\vec n\\otimes \\vec n$ given in terms of the inhomogeneous unit director field distribution $\\vec n\\in\\mathbb{R}^3$.

Kaushik Bhattacharya; Marta Lewicka; Mathias Schffner

2014-01-08

139

Adherent protective coatings plated on magnesium-lithium alloy  

NASA Technical Reports Server (NTRS)

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.

1965-01-01

140

Thick Toenails  

MedlinePLUS

... 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 and or and or or, browse by ...

141

Bipolar battery plate  

NASA Technical Reports Server (NTRS)

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.

Rowlette, John J. (Inventor)

1987-01-01

142

Plating Processes Utilizing High Intensity Acoustic Beams  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

143

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

PubMed

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() (bioMrieux SA, Marcy l'Etoile, France). In addition, three selective plating agars were compared; modified charcoal cefoperazone deoxycholate agar (mCCDA), CampyFood agar() (CFA; bioMrieux 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 48h 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 24h followed by plating on mCCDA gave a higher number of positive samples (20/49) than 48h enrichment in Bolton broth and plating on mCCDA (15/49). Enrichment in Bolton broth for 48h followed by plating on CFA recovered 35% of samples below the limit for quantifications (<10CFU/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

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

2011-09-01

144

Plate Tectonics  

NSDL National Science Digital Library

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.

2006-01-01

145

30 CFR 20.13 - Approval plate.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

146

30 CFR 20.13 - Approval plate.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

147

30 CFR 20.13 - Approval plate.  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

148

30 CFR 20.13 - Approval plate.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

149

Parallel Plate Antenna.  

National Technical Information Service (NTIS)

The invention as disclosed is a parallel plate antenna having a number of stacked horizontal plates and two vertical plates. Alternating ones of the horizontal plates are electrically coupled to one vertical plate such that the horizontal plates coupled t...

D. F. Rivera

2009-01-01

150

Ballistic Limit of CFRP Plates  

Microsoft Academic Search

JAXA has carried out the hypervelocity impact tests of carbon fiber reinforced plastic (CFRP) plates together with University of Padova. Quasi-isotropic CFRP plates of 2.3, 3.5, and 4.7 mm in thickness were tested. Aluminum sphere of 0.8 to 2.9 mm in diameter was used as projectiles. With a two-stage light gas gun, the projectile was launched with a velocity range

Masumi Higashide; Yosuke Nagao; Seishiro Kibe; Alessandro Francesconi; Daniele Pavarin

2009-01-01

151

Efficient magnetic flier plate propulsion  

Microsoft Academic Search

Factors which govern the efficient propulsion of magnetic flier plates by capacitor banks are discussed. The advantages of a unidirectional crowbarred current discharge for the propulsion of energetic flier plates are demonstrated by an experiment in which 1.4 m2 of 0.046 cm thick copper sheet was accelerated to 310 m s-1. The flier terminal velocity was measured both by multiple-flash

R. Bealing; P. G. Carpenter

1976-01-01

152

Reconciling strong slab pull and weak plate bending: The plate motion constraint on the strength of mantle slabs  

E-print Network

Keywords: subduction zones plate bending mantle slabs plate tectonics mantle convection rheology Although. This gentle bending may ultimately permit plate tectonics on Earth. © 2008 Elsevier B.V. All rights reserved is fundamental to plate tectonics because it allows the entire thickness of the oceanic lithosphere

Demouchy, Sylvie

153

Plate Motions  

NSDL National Science Digital Library

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.

Nunn, Jeffrey

154

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.

2002-09-01

155

THREE-DIMENSIONAL ANALYSIS OF TRANSIENT THERMAL STRESSES IN FUNCTIONALLY GRADED PLATES  

E-print Network

: Functionally graded material, thick plate, thermal stress, elasticity solution 1 Assistant Professor, senthilTHREE-DIMENSIONAL ANALYSIS OF TRANSIENT THERMAL STRESSES IN FUNCTIONALLY GRADED PLATES Senthil S deformations of a simply supported functionally graded (FG) rectangular plate subjected to time

Vel, Senthil

156

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

NASA Technical Reports Server (NTRS)

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.

Johnson, S.

1976-01-01

157

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

SciTech Connect

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.

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

158

Deflection and stress-resultants of axisymmetric mindlin plates in terms of corresponding Kirchhoff solutions  

Microsoft Academic Search

The Kirchhoff plate theory, when used for the analysis of bending of plates that are relatively thick, underpredicts the deflections. This is because it does not account for the effect of transverse shear deformation which becomes significant in thick plates. A more refined plate theory proposed by Mindlin allows for this shear deformation effect by relaxing the condition that the

C. M. Wang; K. H. Lee

1996-01-01

159

3D Finite Element Analysis Of The Tube Plate Stress Strain State  

Microsoft Academic Search

The choice of optimal tube plate thickness of high-pressure preheaters of chamber-type (HPCP) by modern computation methods is an actual engineer problem. In the paper the scheme, which allows defining the tube plate thickness of the HPCP by finite element (FE) modeling with application of the composite structure mechanics methods is presented. Tube plate thickness was chosen with the use

Alexey I. Borovkov; Victor S. Modestov; Dmitry B. Birukov; Sergey O. Gostevskich; Evgeny V. Pereyaslavets

160

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

PubMed

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

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

2014-01-01

161

Assessment of the chest wall thickness of the lawrence livermore torso phantom using a voxel image.  

PubMed

This paper describes the methodology of measuring the chest wall thickness using the voxel image of the Lawrence Livermore National Lab (LLNL) torso phantom. The LLNL phantom is used as a standard to calibrate a lung counter consisting of a 2 2 array of germanium detectors. In general, an average thickness estimated from four counting positions is used as the chest wall thickness for a given overlay plate. For a given overlay, the outer chest surface differs from that of inner one, and the chest wall thickness varies from one position to other. The LLNL phantom with chest plate and C4 overlay plate installed was scanned with a CT (computed tomography) scanner. The image data, collected in DICOM (Digital Imaging and Communication) format, were converted to the MCNP input file by using the Scan2Mcnp program. The MCNP file was visualized and analyzed with the Moritz visual editor. An analytic expression was formulated and solved to calculate the chest wall thickness by using the point detector responses (F 5 tally of MCNP). To map the chest thickness, the entire chest wall was meshed into virtual grids of 1 cm width. A source and detector pair was moved along the inner and outer surface of the chest wall from right to left at different heights from neck to abdomen. For each height (z(k)), (x(i), y(j)) coordinates for the detector source pair were calculated from the visual editor and were scaled on-screen. For each (x(i), y(j), z(k)) position, a mesh thickness was measured from on-screen measurement and by solving the detector responses. The chest wall thicknesses at different positions on the outer surface of the chest were compared and verified using two methods. PMID:22004927

Ahmed, A S M Sabbir; Capello, Kevin; Kramer, Gary H

2011-06-01

162

Preparation of thick molybdenum targets  

NASA Technical Reports Server (NTRS)

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.

Singh, J. J.

1974-01-01

163

Bipolar battery plate  

NASA Technical Reports Server (NTRS)

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.

Rowlette, John J. (Inventor)

1985-01-01

164

Stability optimization of laminated composite plates  

NASA Technical Reports Server (NTRS)

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

Hirano, Y.

1980-01-01

165

Cadmium plating replacements  

SciTech Connect

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.

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

1995-03-01

166

Cadmium plating replacements  

NASA Technical Reports Server (NTRS)

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.

Nelson, Mary J.; Groshart, Earl C.

1995-01-01

167

Plate TectonicsPlate Tectonics Plate TectonicsPlate Tectonics  

E-print Network

ridge systems #12;Concentration of earthquakes #12;Mid-ocean ridge systems #12;Deep Sea Drilling Project, transform boundaries ­ travel 1 to 11 cm/yr relative to one another #12;14 tectonic plates today #12;Mid-ocean

Siebel, Wolfgang

168

Musical Plates: A Study of Plate Tectonics  

NSDL National Science Digital Library

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.

2007-01-01

169

Vibrations of twisted cantilevered plates - Experimental investigation  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

170

Shear bands and cracking of metallic glass plates in bending  

Microsoft Academic Search

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

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

2006-01-01

171

Short report: an agar plate method for culturing hookworm larvae: analysis of growth kinetics and infectivity compared with standard coproculture techniques.  

PubMed

An agar plate (AP) method has been developed for culturing infectious larvae of the hookworm Ancylostoma ceylanicum. The third-stage larvae reared using the AP method displayed similar morphology to those cultured using Baermann or Harada-Mori coproculture techniques. The yield of viable larvae from the AP method (50%) was comparable to that of the Baermann (47%), and both were superior to Harada-Mori (2.1%). Third-stage larvae cultured by the AP method established patent infection in naturally permissive laboratory hosts, although the yield of adult worms was reduced compared with animals infected with L3 obtained by Baermann culture. The AP method is useful for defining growth requirements for hookworm development, as well as characterizing the effects of bacterially expressed compounds on hookworm larvae in vivo. PMID:18165527

Reiss, Daniel; Harrison, Lisa M; Bungiro, Richard; Cappello, Michael

2007-12-01

172

Determining dielectric constants using a parallel plate capacitor  

Microsoft Academic Search

The availability of low cost digital multimeters capable of measuring capacitance has made parallel plate capacitor investigations common in the introductory laboratory. Typically, students add multiple thin sheets of dielectric material between conducting plates. The capacitance is measured and then plotted versus the reciprocal of the dielectric thickness (the nominal plate separation). We explain why the experiment fails for small

T. T. Grove; M. F. Masters; R. E. Miers

2005-01-01

173

Effect of multiple reflections in retardation plates with elliptical birefringence  

NASA Astrophysics Data System (ADS)

The theory of elliptical retardation plates that takes into account a phenomenon of multiple reflections is presented. An analytical form of a transition matrix for a normally incident plane wave is shown. Sample calculations of phase shift introduced by quartz retardation plates and of the output-beam parameters as a function of plate thickness and optical axis orientation are done.

Pietraszkiewicz, Kazimierz; Wozniak, Wladyslaw A.; Kurzynowski, Piotr

1995-02-01

174

Seismic evidence for a moderately thick lithosphere beneath the Siberian Platform  

E-print Network

on the fast-moving Australian plate, suggests that a moderately thick seismic lithosphere beneath Precambrian. Our observation of a $200 thick seismic lithosphere beneath the Siberian platform on the slow-moving Eurasian plate, similar to the thickness of the seismic lithosphere beneath Precambrian terrains

175

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

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...

American Society for Testing and Materials. Philadelphia

2001-01-01

176

Impact on multilayered composite plates  

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

177

Statistical tests of additional plate boundaries from plate motion inversions  

NASA Technical Reports Server (NTRS)

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.

Stein, S.; Gordon, R. G.

1984-01-01

178

Tube wall thickness measurement apparatus  

DOEpatents

An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

Lagasse, Paul R. (Santa Fe, NM)

1987-01-01

179

Tube wall thickness measurement apparatus  

DOEpatents

An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

Lagasse, P.R.

1985-06-21

180

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

NSDL National Science Digital Library

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.

Egger, Anne

2003-03-18

181

Elastic Plate Deformation with Transverse Variation of Microrotation  

E-print Network

The purpose of this paper is to present a new mathematical model for the deformation of thin Cosserat elastic plates. Our approach, which is based on a generalization of the classical Reissner plate theory, takes into account the transverse variation of microrotation of the plates. The model assumes polynomial approximations over the plate thickness of asymmetric stress, couple stress, displacement, and microrotation, which are consistent with the elastic equilibrium, boundary conditions and the constitutive relationships. Based on the generalized Hellinger-Prange -Reissner variational principle and strain-displacement relation we obtain the complete theory of Cosserat plate. We also proved the solution uniqueness for the plate boundary value problem.

Lev Steinberg

2008-11-10

182

Electromagnetic semitransparent $?$-function plate: Casimir interaction energy between parallel infinitesimally thin plates  

E-print Network

We derive boundary conditions for electromagnetic fields on a $\\delta$-function plate. The optical properties of such a plate are shown to necessarily be anisotropic in that they only depend on the transverse properties of the plate. We unambiguously obtain the boundary conditions for a perfectly conducting $\\delta$-function plate in the limit of infinite dielectric response. We show that a material does not "optically vanish" in the thin-plate limit. The thin-plate limit of a plasma slab of thickness $d$ with plasma frequency $\\omega_p^2=\\zeta_p/d$ reduces to a $\\delta$-function plate for frequencies ($\\omega=i\\zeta$) satisfying $\\zeta d \\ll \\sqrt{\\zeta_p d} \\ll 1$. We show that the Casimir interaction energy between two parallel perfectly conducting $\\delta$-function plates is the same as that for parallel perfectly conducting slabs. Similarly, we show that the interaction energy between an atom and a perfect electrically conducting $\\delta$-function plate is the usual Casimir-Polder energy, which is verified by considering the thin-plate limit of dielectric slabs. The "thick" and "thin" boundary conditions considered by Bordag are found to be identical in the sense that they lead to the same electromagnetic fields.

Prachi Parashar; Kimball A. Milton; K. V. Shajesh; M. Schaden

2012-06-01

183

Quaternions as astrometric plate constants  

NASA Technical Reports Server (NTRS)

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

Jefferys, William H.

1987-01-01

184

30 CFR 56.12032 - Inspection and cover plates.  

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

185

46 CFR 64.53 - Information plate for MPTs.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

186

46 CFR 64.53 - Information plate for MPTs.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

187

46 CFR 64.53 - Information plate for MPTs.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

188

46 CFR 64.53 - Information plate for MPTs.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

189

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

NASA Astrophysics Data System (ADS)

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.

Sedlak, Petr; Hirose, Yuichiro; Enoki, Manabu

2013-04-01

190

Heat Treatment of Friction-Stir-Welded 7050 Aluminum Plates  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

191

Stop motion microphotography of laser driven plates  

SciTech Connect

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

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

1994-09-01

192

TFSSRA - THICK FREQUENCY SELECTIVE SURFACE WITH RECTANGULAR APERTURES  

NASA Technical Reports Server (NTRS)

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.

Chen, J. C.

1994-01-01

193

New heat transfer and friction factor design data for perforated plate heat exchangers  

Microsoft Academic Search

Perforated plate heat exchangers have been found to have inherently low axial conduction and are therefore excellent candidates for cryogenic applications where an all-metal design is required. A total of three plate cores were tested; two were chemically etched and the other mechanically punched. Hole size, percent open area and plate thickness parameters were varied among the plates. Experimental results

Richard H. Hubbell; Christina L. Cain

1988-01-01

194

Computing relative plate velocities: a primer  

SciTech Connect

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.

Bevis, M.

1987-08-01

195

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.

196

Natural frequencies of twisted rotating plates  

NASA Technical Reports Server (NTRS)

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

Ramamurti, V.; Kielb, R.

1984-01-01

197

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)

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.

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

2013-09-01

198

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

E-print Network

~mplitudes Found. by t, he Amplitude Pickup Instruments for l/8- in. Plat e 0 ~ 0 ~ 0 ~ eeoc' Bibliography ~ o ~ eoaa gaea VIBRATION OP CIRCULAR PLi'. TZS, OF SEVERAL THICi'KZSSZS, ;11TH THREE SUFPORTS INTRODUCTION The different. 1al equations for the vibrat.... ion of thin plat, es ancl clast, ic bodies with cert, ain simple boundary conditions snd. certain definite support configurations have been solved, Many texts on vibrations have these solut, iona, but their' solution reouires idea3. 1zations...

Ballentine, John Richard

2012-06-07

199

49 CFR 179.400-8 - Thickness of plates.  

Code of Federal Regulations, 2012 CFR

...see 171.7 of this subchapter), in psi; E = 0.9, a factor representing the...for Tank Cars, Appendix M, Table M1, in psi; E = 0.9, a factor representing the...for Tank Cars, appendix M, table M1, in psi; E = 0.9, a factor representing...

2012-10-01

200

49 CFR 179.400-8 - Thickness of plates.  

Code of Federal Regulations, 2011 CFR

...see 171.7 of this subchapter), in psi; E = 0.9, a factor representing the...for Tank Cars, Appendix M, Table M1, in psi; E = 0.9, a factor representing the...for Tank Cars, appendix M, table M1, in psi; E = 0.9, a factor representing...

2011-10-01

201

49 CFR 179.400-8 - Thickness of plates.  

Code of Federal Regulations, 2010 CFR

...see 171.7 of this subchapter), in psi; E = 0.9, a factor representing the...for Tank Cars, Appendix M, Table M1, in psi; E = 0.9, a factor representing the...for Tank Cars, appendix M, table M1, in psi; E = 0.9, a factor representing...

2010-10-01

202

49 CFR 179.400-8 - Thickness of plates.  

Code of Federal Regulations, 2013 CFR

...see 171.7 of this subchapter), in psi; E = 0.9, a factor representing the...for Tank Cars, Appendix M, Table M1, in psi; E = 0.9, a factor representing the...for Tank Cars, appendix M, table M1, in psi; E = 0.9, a factor representing...

2013-10-01

203

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

E-print Network

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

Milan Batista

2010-07-15

204

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

PubMed

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

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

2013-12-01

205

Thermal equivalency study for steel propulsion shafting and flat plate  

SciTech Connect

The electroslag strip surfacing (ESS) process despite its advantage of high deposition rates, low base metal dilutions, and uniform penetrations, over unknown in the United States and has only recently started to gain acceptance as a feasible process for surfacing on large components, e.g., propulsion shafting. Electroslag strip surfacing was made on service scale shaft and on various flat plates using the same surfacing materials and parameters. Thermal history measurements were made by chromel-alumel thermocouples mounted on the shaft and the flat plates. The data were collected by a computer-controlled data acquisition system and subsequently postprocessed using commercial spreadsheet/graphics software programs. The t{sub 8-5} cooling times for the shaft and the flat plates showed a strong dependence on the interpass preheat temperature, but was independent of the maximum temperature. The t{sub 8-5} cooling times for the shaft and flat plate of the same thickness, and for the 76 and 127 mm thick flat plates were found to match very closely. This led to the conclusion that the thermal history results for 127 mm thick shaft and 127 to 67 mm thick flat plates made from similar steels show thermal equivalence for ESS and provide the justification for using 67 to 127 mm thick plates instead of 127 mm thick service scale shafting for process characterization.

Dikshit, V.A.; Atteridge, D.G.

1994-12-31

206

Steady-state heat conduction in multilayered composite plates and shells  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

207

Volcano spacing and plate rigidity  

SciTech Connect

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.

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

1991-04-01

208

MTR plates modeling with MAIA  

SciTech Connect

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)

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

209

Cerebral Cortical Thickness Measurements  

Microsoft Academic Search

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 \\

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

2004-01-01

210

Measuring insulation thickness  

NASA Technical Reports Server (NTRS)

Calibrated eddy-current meter measures thickness of thermal insulation on metal substrates with specially designed adapters; for example, thickness of fiberglass parts for boats or automobiles. Technique is particlarly useful for sprayed-on insulation.

Munn, D. M.

1979-01-01

211

Plate Tectonics Animation  

NSDL National Science Digital Library

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.

2002-01-01

212

Toward the Standard Population Synthesis Model of the X-Ray Background: Evolution of X-Ray Luminosity and Absorption Functions of Active Galactic Nuclei Including Compton-thick Populations  

NASA Astrophysics Data System (ADS)

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

Ueda, Yoshihiro; Akiyama, Masayuki; Hasinger, Gnther; Miyaji, Takamitsu; Watson, Michael G.

2014-05-01

213

Inevitability of Plate Tectonics on Super-Earths  

E-print Network

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.

Valencia, Diana; Sasselov, Dimitar D

2007-01-01

214

Inevitability of Plate Tectonics on Super-Earths  

E-print Network

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.

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

2007-10-03

215

Inevitability of Plate Tectonics on Super-Earths  

E-print Network

The recent discovery of super-Earths (masses ? 10 M?) has initiated a discussion about conditions for habitable worlds. Among these is the mode of convection, which influences a planets 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. Subject headings: planetary systems planets and satellites Earth 1 corresponding author 2

Diana Valencia; Richard J. Oconnell; Dimitar D. Sasselov

216

Mapping Plate Tectonic Boundaries  

NSDL National Science Digital Library

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.

Kerwin, Michael

217

Minimal Pixilated Resistive Plate Chamber  

NASA Astrophysics Data System (ADS)

Two conducting plates, separated by a suitable gas at atmospheric pressure, can be used as a detector for minimum ionizing particles. However, if a spark develops the energy carried by the spark can damage the surface of the plates. The energy available to a spark can be reduced to a harmless level by covering one of the plates with a material with a high resistance. This insulating layer must be thick enough so that transient voltages do not punch holes in the layer (0.2-0.5 mm). The resistance between the front and the back of the layer needs to be large but still small enough so that the surface charge can be replenished in a time of the order of one microsecond. This requires a resistance of the order of 500 M?/cm^2, which is in the range of ceramic enamels that are made for application to metal surfaces. The other plate can be divided into pixels, in effect making a number of separate detectors.

Norbeck, Edwin; Onel, Yasar

2009-10-01

218

Characterizing Plate Boundaries  

NSDL National Science Digital Library

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 along the length of a boundary. Showing them what you mean using snapshots from a map can often clear questions like this up quickly. Similarly, for written work a single example that gives them a clear sense of "what you're looking for" and can often head off a lot of questions. (2) Choose the boundaries you ask students to study carefully. The scarcity of documented volcanism along a mid-ocean ridge or the burial of seafloor age belts by sediment along a trench can result in student observations that are correct, but problematic for correctly assessing the nature of a boundary. (3) Stay on top of student questions and comments, and be prepared to make well-publicized "mid-course corrections" if something you thought was clear turns out to be misunderstood. These minor corrections happen naturally in face-to-face classes but can require real diligence to catch and correct in the online environment.

Hirt, Bill

219

Compression buckling response of tailored rectangular composite plates  

NASA Technical Reports Server (NTRS)

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.

Biggers, Sherrill B.; Srinivasan, Sundar

1993-01-01

220

Stamping and wrinkling of elastic plates  

E-print Network

We study the peculiar wrinkling pattern of an elastic plate stamped into a spherical mold. We show that the wavelength of the wrinkles decreases with their amplitude, but reaches a maximum when the amplitude is of the order of the thickness of the plate. The force required for compressing the wrinkled plate presents a maximum independent of the thickness. A model is derived and verified experimentally for a simple one-dimensional case. This model is extended to the initial situation through an effective Young modulus representing the mechanical behavior of wrinkled state. The theoretical predictions are shown to be in good agreement with the experiments. This approach provides a complement to the "tension field theory" developed for wrinkles with unconstrained amplitude.

J. Hure; B. Roman; J. Bico

2012-06-30

221

Combinatorial performance characteristics of agitated nickel hypophosphite electroless plating baths  

Microsoft Academic Search

In this article, we present the combinatorial performance characteristics of agitated sodium hypophosphite electroless plating baths. Various performance characteristics assessed include bath conversion, plating efficiency, selective conversion, metal film thickness, average pore size, effective porosity and percent pore densification (PPD). Bath agitation was brought forward by rotating a symmetric disk shaped porous ceramic substrate with a nominal pore size of

Vijaya Kumar Bulasara; Harjyoti Thakuria; Ramgopal Uppaluri; Mihir Kumar Purkait

2011-01-01

222

Multilayer plated wire shows promise as memory device  

NASA Technical Reports Server (NTRS)

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

Kadish, D.

1968-01-01

223

Automated design of composite plates for improved damage tolerance  

NASA Technical Reports Server (NTRS)

The present effort toward design automation for local damage tolerance in composite plates under compressive loading, simulating the local damage condition by a central, through-the-thickness crack-like notch, uses a micromechanical failure model for the fiber kink formation in the load-carrying layers. This accounts for the combined effects of compressive and shearing stresses around the notch. For stiffened plates, minimum-weight configurations are obtained where the crack is isolated in low stiffness plate regions.

Gurdal, Zafer; Haftka, Raphael T.

1988-01-01

224

Air-coupled thickness measurements of stainless steel  

E-print Network

A method of measuring the thickness of steel plates using through transmission of an acoustic pulse is demonstrated. This study has been done on a stainless steel plate with regions of thickness 10:0 mm, 9:8 mm, and 9:6 mm, using broadband pulses with energy in 200 kHz to 600 kHz band. Ultimately the goal is to perform similar air-coupled thickness measurements in a single sided pitch-catch measurement setup. The spectra of the transmitted pulses show the first and second harmonics of the compressional waves in the plate. When compared to a plane wave model of a fluid layer embedded in air, the second harmonic of the plate resonance fits well with the expected value. However, the first harmonic deviates such that the plate appears thicker at this resonance. This is believed to be caused by the finite aperture of the transmitting transducer, causing deviations from a plane wave. Thickness differences of 0:2 mm between the different regions of the plate were shown to be resolved. A third peak was found in the s...

Waag, Grunde; Norli, Petter

2012-01-01

225

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

SciTech Connect

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.

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

226

CMUT Fabrication Based On A Thick Buried Oxide Layer  

PubMed Central

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

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

2010-01-01

227

External Resource: Plate Tectonics  

NSDL National Science Digital Library

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.

1900-01-01

228

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.

229

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.

230

40 CFR Table 1 to Subpart Wwwwww... - Applicability of General Provisions to Plating and Polishing Area Sources  

Code of Federal Regulations, 2013 CFR

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

2013-07-01

231

40 CFR Table 1 to Subpart Wwwwww... - Applicability of General Provisions to Plating and Polishing Area Sources  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

232

European Journal of Mechanics A/Solids 25 (2006) 215229 The response of clamped sandwich plates with lattice cores  

E-print Network

resistance than monolithic plates of equal mass, and the square-honeycomb sandwich plates outperformEuropean Journal of Mechanics A/Solids 25 (2006) 215�229 The response of clamped sandwich plates circular monolithic and sandwich plates of equal areal mass and thickness has been measured by loading

Fleck, Norman A.

233

The nonlinear transient response of thin, rectangular elastic plates  

NASA Technical Reports Server (NTRS)

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

Rajagopal, G.; Lowery, R. L.

1976-01-01

234

Plate Tectonic Primer  

NSDL National Science Digital Library

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.

Fichter, Lynn

235

Optimal truss plates  

Microsoft Academic Search

Sandwich plates comprised of truss cores faced with either planar trusses or solid sheets are optimally designed for minimum weight subject to prescribed combinations of bending and transverse shear loads. Motivated by recent advances in manufacturing possibilities, attention is focussed on plates with truss elements and faces made from a single material. The optimized plates are compared with similarly optimized

Nathan Wicks; John W Hutchinson

2001-01-01

236

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.

237

Thick film hydrogen sensor  

Microsoft Academic Search

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.

B. S. Hoffheins; R. J. Lauf

1995-01-01

238

Pavement Thickness Design Parameter  

E-print Network

Pavement Thickness Design Parameter Impacts 2012 Municipal Streets Seminar November 14, 2012 Paul D Thickness Design · Design Traffic ­ Average daily traffic volume ­ Percent trucks on the street · Usually 2RoadXpress (Asphalt Institute) ­ American Concrete Paving Association · StreetPave ­ AASHTO 1993 Pavement Design Guide

239

Education and "Thick" Epistemology  

ERIC Educational Resources Information Center

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

Kotzee, Ben

2011-01-01

240

Accurate stress resultants equations for laminated composite deep thick shells  

SciTech Connect

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.

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

1995-11-01

241

Rotation angle measurement based on white-light interferometry with a standard optical flat.  

PubMed

We propose a simple white-light interferometric method of measuring a one-dimensional rotation angle with use of an optical plane parallel plate of standard refractive index. The phase change of the interference pattern of the interferometer during the rotation of the flat plate of known refractive index and thickness placed in one of the interferometer's arms is used for determination of the rotation angle. This method has been demonstrated for an accurate angle measurement over the angle range from 0 to 40 within a maximum uncertainty of 0.057. PMID:22358161

Yun, Hyo Geun; Kim, Seung Hwan; Jeong, Heung Sun; Kim, Kyong Hon

2012-02-20

242

Plate Tectonics: Moving Middle School Science  

NSDL National Science Digital Library

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.

Barber, Carolee; Ridgway, Judith

2004-11-01

243

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

NASA Technical Reports Server (NTRS)

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.

Biricikoglu, V.

1971-01-01

244

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

Microsoft Academic Search

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

S. S. Akavci

2007-01-01

245

An improved plating process  

NASA Technical Reports Server (NTRS)

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.

Askew, John C.

1994-01-01

246

Discovering Plate Boundaries  

NSDL National Science Digital Library

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

Henning, Alison

247

Paper microzone plates.  

PubMed

This paper describes 96- and 384-microzone plates fabricated in paper as alternatives to conventional multiwell plates fabricated in molded polymers. Paper-based plates are functionally related to plastic well plates, but they offer new capabilities. For example, paper-microzone plates are thin (approximately 180 microm), require small volumes of sample (5 microL per zone), and can be manufactured from inexpensive materials ($0.05 per plate). The paper-based plates are fabricated by patterning sheets of paper, using photolithography, into hydrophilic zones surrounded by hydrophobic polymeric barriers. This photolithography used an inexpensive formulation photoresist that allows rapid (approximately 15 min) prototyping of paper-based plates. These plates are compatible with conventional microplate readers for quantitative absorbance and fluorescence measurements. The limit of detection per zone loaded for fluorescence was 125 fmol for fluorescein isothiocyanate-labeled bovine serum albumin, and this level corresponds to 0.02 the quantity of analyte per well used to achieve comparable signal-to-noise in a 96-well plastic plate (using a solution of 25 nM labeled protein). The limits of detection for absorbance on paper was approximately 50 pmol per zone for both Coomassie Brilliant Blue and Amaranth dyes; these values were 0.4 that required for the plastic plate. Demonstration of quantitative colorimetric correlations using a scanner or camera to image the zones and to measure the intensity of color, makes it possible to conduct assays without a microplate reader. PMID:19572563

Carrilho, Emanuel; Phillips, Scott T; Vella, Sarah J; Martinez, Andres W; Whitesides, George M

2009-08-01

248

Thick sandwich panel fabrication for bridge deck structure and its joint strength  

NASA Astrophysics Data System (ADS)

The purpose of this study is to evaluate the static strength of thick plate laser welded lap joint and the performance of thick sandwich panel for bridge deck structure. The strength of thin sheet laser welded lap joint whose thickness is less than 1.6 mm have been already reported, but the strength of thick plate laser welded lap joint whose thickness is more than 10 mm is not known. The authors believe this thick laser welded lap jont enable heavy industries to make a revolution on applying it for sandwich panel fabrication. Then, they have conducted mechanical tests of 10 mm + 6 mm thick laser welded lap joints to grasp their static strength. According to the obtained data, they fabricate a thick sandwich panel model of newly designed bridge deck structure for evaluation. The static lading test, cyclic loading test and collapsing test show that the thick sandwich panel has enough performance for the practical application.

Kitagawa, Akikazu; Fukuda, Naoaki; Takeda, Shinnosuke; Matsunawa, Akira

2003-03-01

249

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.

250

Screen test for cadmium and nickel plates  

NASA Technical Reports Server (NTRS)

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.

Phan, Angie H.; Zimmerman, Albert H.

1994-01-01

251

Waveguiding in two-dimensional piezoelectric phononic crystal plates  

NASA Astrophysics Data System (ADS)

We investigate the possibility of designing phononic crystal-based devices for telecommunication applications using materials commonly employed in microfabrication. We focus our attention on a phononic crystal made of a square array of cylindrical holes drilled in an active piezoelectric PZT5A matrix. Two different structures are considered, namely, a freestanding phononic crystal plate and a plate deposited on a silicon substrate. The geometrical characteristics of the phononic crystal plates (lattice parameter and thickness) were chosen to ensure the existence of an absolute band gap around 1.5GHz; a common frequency in radio frequency telecommunications. Computations of the dispersion curves of these active structures were conducted with the help of the finite element method. We demonstrate the existence of absolute band gaps in the band structure of the phononic crystal plates and, then, the possibility of guided modes inside a linear defect created by removing one row of air holes in the phononic crystal. In the case of the supported phononic crystal plates, we show the existence of an absolute forbidden band in the plate modes when the thickness of the substrate significantly exceeds the plate thickness. We discuss the conditions to realize waveguiding through a linear defect inside the supported plate. The present work provides evidences that phononic crystal properties can be integrated with existing silicon based microdevice technology.

Vasseur, J. O.; Hladky-Hennion, A.-C.; Djafari-Rouhani, B.; Duval, F.; Dubus, B.; Pennec, Y.; Deymier, P. A.

2007-06-01

252

Combination field plate\\/field ring termination structures for integrated power devices  

Microsoft Academic Search

The issues associated with termination structure design for vertical, integrated power devices are defined. The interaction of the oxide thickness running over the device isolation and the breakdown voltage of the device is explored. In light of these constraints, a comparison of single field plate, two-level field plate, field ring only, and combination field plate\\/field ring termination structures is performed.

S. L. Kosier; A. Wei; M. A. Shibib; J. C. Desko; R. D. Schrimpf; K. F. Galloway; K. C. Yau

1993-01-01

253

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

Microsoft Academic Search

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

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

1991-01-01

254

Characterization of oligodeoxyribonucleotide synthesis on glass plates  

PubMed Central

Achieving high fidelity chemical synthesis on glass plates has become increasingly important, since glass plates are substrates widely used for miniaturized chemical and biochemical reactions and analyses. DNA chips can be directly prepared by synthesizing oligonucleotides on glass plates, but the characterization of these micro-syntheses has been limited by the sub-picomolar amount of material available. Most DNA chip syntheses have been assayed using in situ coupling of fluorescent molecules to the 5?-OH of the synthesized oligonucleotides. We herein report a systematic investigation of oligonucleotide synthesis on glass plates with the reactions carried out in an automated DNA synthesizer using standard phosphoramidite chemistry. The analyses were performed using 32P gel electrophoresis of the oligonucleotides cleaved from glass plates to provide product distribution profiles according to chain length of oligonucleotides. 5?-Methoxythymidine was used as the chain terminator, which permits assay of coupling reaction yields as a function of chain length growth. The results of this work reveal that a major cause of lower fidelity synthesis on glass plates is particularly inefficient reactions of the various reagents with functional groups close to glass plate surfaces. These problems cannot be detected by previous in situ fluorescence assays. The identification of this origin of low fidelity synthesis on glass plates should help to achieve improved synthesis for high quality oligonucleotide microarrays. PMID:11353087

LeProust, Eric; Zhang, Hua; Yu, Peilin; Zhou, Xiaochuan; Gao, Xiaolian

2001-01-01

255

Linear versus nonlinear theories for laminated composite plates and shells  

SciTech Connect

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).

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

1995-11-01

256

Gradient index lenses for flexural waves based on thickness variations  

NASA Astrophysics Data System (ADS)

This work presents a method for the realization of gradient index devices for flexural waves in thin plates. Unlike recent approaches based on phononic crystals, the present approach is based on the thickness-dependence of the dispersion relation of flexural waves, which is used to create gradient index devices by means of local variations of the plate's thickness. Numerical simulations of known circularly symmetrical gradient index lenses have been performed. These simulations have been done using the multilayer multiple scattering method and the results prove their broadband efficiency and omnidirectional properties. Finally, finite element simulations employing the full three-dimensional elasticity equations also support the validity of the designed approach.

Climente, Alfonso; Torrent, Daniel; Snchez-Dehesa, Jos

2014-08-01

257

Three-dimensional heat flow and solidification during the autogenous GTA welding of aluminum plates  

Microsoft Academic Search

A theoretical and experimental study of heat flow and solidification during the autogenous GTA welding of aluminum plates\\u000a was carried out. The theoretical part of the study involves the development of a computer model which describes three-dimensional\\u000a heat flow during welding. The model, though valid for any plate thickness, is particularly useful for moderately thick plates\\u000a since both full- and

S. Kou; Y. Le

1983-01-01

258

Fuel Cell Thermal Management Through Conductive Cooling Plates  

NASA Technical Reports Server (NTRS)

An analysis was performed to evaluate the concept of utilizing conductive cooling plates to remove heat from a fuel cell stack, as opposed to a conventional internal cooling loop. The potential advantages of this type of cooling system are reduced stack complexity and weight and increased reliability through the reduction of the number of internal fluid seals. The conductive cooling plates would extract heat from the stack transferring it to an external coolant loop. The analysis was performed to determine the required thickness of these plates. The analysis was based on an energy balance between the thermal energy produced within the stack and the heat removal from the cooling plates. To accomplish the energy balance, the heat flow into and along the plates to the cooling fluid was modeled. Results were generated for various numbers of cells being cooled by a single cooling plate. The results provided cooling plate thickness, mass, and operating temperature of the plates. It was determined that utilizing high-conductivity pyrolitic graphite cooling plates can provide a specific cooling capacity (W/kg) equivalent to or potentially greater than a conventional internal cooling loop system.

Colozza, Anthony J.; Burke, Kenneth A.

2008-01-01

259

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

260

Laser-printing of toner-based 96-microzone plates for immunoassays.  

PubMed

This work describes the quick and simple fabrication of toner-based 96-microzone plates by a direct-printing technology. The printer deposits a toner layer (ca. 5 ?m thick) on the polyester surface which acts as a hydrophobic barrier to confine small volumes of sample on test zones (wells). A 96-microzone toner plate was explored to demonstrate its capability of performing enzyme-linked immunosorbent assay (ELISA). The detection of anti-immunoglobulin G (anti-IgG) and immunoglobulin M (IgM) antibodies has been successfully achieved in cell culture and serum samples, respectively. The use of a conventional microplate reader has allowed obtaining a limit of detection of 13 fmol of mouse IgG per zone on printed microplates. The IgM antibody has been detected in a serum sample collected from a patient infected with dengue virus. The detection of a primary infection has been provided by a microplate reader and also by a cell phone camera. Besides the bioanalytical feasibility, toner-based zones have shown good repeatability for inter-zone and intra-plate comparisons. The relative standard deviation (RSD) values for inter-zone (n = 12) and intra-plate (n = 3) comparisons were lower than 6% and 11%, respectively. Furthermore, it was found that the lifetime of each printed microplate depends on the storage temperature. The shelf life for devices stored at 10 C has been estimated to be ca. four weeks. PMID:23248817

Oliveira, Karoliny Almeida; Rodrigues de Oliveira, Cristina; Antonelli da Silveira, Lucimeire; Coltro, Wendell Karlos Tomazelli

2013-02-21

261

A double layer plaque assay using spread plate technique for enumeration of bacteriophage MS2.  

PubMed

Bacteriophage MS2 is used widely as a model organism to estimate pathogenic virus survival in various environments, and is usually quantified by plaque assay. Although current plaque assays work well in enumeration of MS2 in environmental samples, quantification of MS2 calls for better visibility and higher consistency. In an attempt to improve the visibility and consistency of the current plaque assay, spread plate technique was introduced, instead of the pour plate technique used commonly in existing methods. Other parameters that influence the outcome of the plaque assay were also compared. Using spread plate technique resulted in an increase of plaque size by approximately 50% and contributed to a better visibility. Addition of supplements (glucose, CaCl2 and thiamine); reduction of agar thickness and hardness, also contributed to enhanced plaque visibility and increased plaque count. Among all the conditions tested, a supplemented thin bottom agar (10ml 1% agar) and a supplemented thin top agar (10ml 0.45% agar) with spread plate technique gave the maximum countable plaques with a minimum standard deviation. When compared to other methods, it produced significantly higher plaque count and lower variation. The optimized plaque assay significantly improved visibility and consistency of the existing plaque assay methods and could be used in quantification of MS2. PMID:24211298

Cormier, Jiemin; Janes, Marlene

2014-02-01

262

Waveguiding in supported phononic crystal plates  

NASA Astrophysics Data System (ADS)

We investigate, with the help of the finite element method, the existence of absolute band gaps in the band structure of a free-standing phononic crystal plate and of a phononic crystal slab deposited on a substrate. The two-dimensional phononic crystal is constituted by a square array of holes drilled in an active piezoelectric (PZT5A or AlN) matrix. For both matrix materials, an absolute band gap occurs in the band structure of the free-standing plate provided the thickness of the plate is on the order of magnitude of the lattice parameter. When the plate is deposited on a Si substrate, the absolute band gap still remains when the matrix of the phononic crystal is made of PZT5A. The AlN phononic crystal plate losses its gap when supported by the Si substrate. In the case of the PZT5A matrix, we also study the possibility of localized modes associated with a linear defect created by removing one row of air holes in the deposited phononic crystal plate.

Vasseur, J.; Hladky-Hennion, A.-C.; Deymier, P.; Djafari-Rouhani, B.; Duval, F.; Dubus, B.; Pennec, Y.

2007-12-01

263

Thermal diffusivity of nonflat plates using the flash method  

SciTech Connect

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.

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

264

Thick film sol gel PZT transducer using dip coating  

Microsoft Academic Search

A sol gel process has been used to develop a 30 ?m thick PZT coating on a sapphire wafer. The sol gel film was removed and plated with platinum electrodes. The free-standing film had a free dielectric constant (?T) of 820, a thickness-mode coupling coefficient (kt) of 0.17, a speed of sound (c) of 3700 m\\/s, and an acoustic impedance

Kenneth L. Gentry; Jason M. Zara; Sang-Don Bu; Chang-Beom Eom; Stephen W. Smith

2000-01-01

265

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.

266

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.

267

Plate Motion Calculator  

NSDL National Science Digital Library

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

Estey, Lou

268

Introduction to Plate Tectonics  

NSDL National Science Digital Library

In this lab students interpret bathymetric, topography, sea floor ages, and earthquake distributions to reinforce concepts about the different types of plate boundaries. Each student must interpret several sets of data to determine the location and type of plate boundary. To develop a set of basic analytical skills, the students draw several diagrams and graphs to reinforce the data presented in figures. Students are also asked to think critically about plate rates and what happens to the crust at the different plate boundaries. This activity uses online and/or real-time data and has minimal/no quantitative component.

Cochran, Elizabeth

269

Variations in elastic thickness and flexure of the Maracaibo block  

NASA Astrophysics Data System (ADS)

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 30km to 18km with a mean value of 23.6km and a mode of 26km. 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 Mrida 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 Mrida Andes position. The load of the Perij 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.

Arnaiz-Rodrguez, Mariano S.; Audemard, Franck

2014-12-01

270

Elastic Plates Motions with Transverse Variation of Microrotation  

E-print Network

The purpose of this paper is to present a new mathematical model for the dynamics of thin Cosserat elastic plates. Our approach, which is based on a generalization of the classical Reissner-Mindlin plate theory, takes into account the transverse variation of microrotation and corresponding microintertia of the the elastic plates. The model assumes polynomial approximations over the plate thickness of asymmetric stress, couple stress, displacement, and microrotation, which are consistent with the elastic equilibrium, boundary conditions and the constitutive relationships. Based on the generalized Hellinger-Prange-Reissner variational principle for the dynamics and strain-displacement relation we obtain the complete dynamic theory of Cosserat plate. Key words: Cosserat materials, elastic plates, transverse microrotation, variational principle, elastodynamics

Lev Steinberg

2009-01-14

271

Elastic theory of unconstrained non-Euclidean plates  

E-print Network

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.

Efi Efrati; Eran Sharon; Raz Kupferman

2008-10-14

272

Crustal Thickness of Iran Inferred from Converted Waves  

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

273

Composite plates impact damage - An atlas  

NASA Technical Reports Server (NTRS)

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.

Finn, Scott R.; Springer, George S.

1991-01-01

274

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)

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.

1976-01-01

275

Spreading continents kick-started plate tectonics  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

276

Spreading continents kick-started plate tectonics.  

PubMed

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

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

2014-09-18

277

Industrialization of the ion plating process  

NASA Technical Reports Server (NTRS)

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

Spalvins, T.

1976-01-01

278

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.

279

Accurate license plate localization  

Microsoft Academic Search

Vehicle license plate identification system is an image- processing technology used to identify vehicles by their license plates. This technology is used in various security and traffic applications. This data is also used for enforcement, data collection, and can be used to keep a time record on the entry or exit of vehicles for automatic payment calculations. The significant advantage

S. Mohamed Mansoor Roomi; M. Anitha; R. Bhargavi

2011-01-01

280

Mapping Plate Boundaries  

NSDL National Science Digital Library

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.

Johnson, Rurik

2009-11-12

281

Wave propagation of functionally graded material plates in thermal environments.  

PubMed

The wave propagation of an infinite functionally graded plate in thermal environments is studied using the higher-order shear deformation plate theory. The thermal effects 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 in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Considering the effects of transverse shear deformation and rotary inertia, the governing equations of the wave propagation in the functionally graded plate are derived by using the Hamilton's principle. The analytic dispersion relation of the functionally graded plate is obtained by solving an eigenvalue problem. Numerical examples show that the characteristics of wave propagation in the functionally graded plate are relates to the volume fraction index and thermal environment of the functionally graded plate. The influences of the volume fraction distributions and temperature on wave propagation of functionally graded plate are discussed in detail. The results carried out can be used in the ultrasonic inspection techniques and structural health monitoring. PMID:21663930

Sun, Dan; Luo, Song-Nan

2011-12-01

282

49 CFR 229.85 - Doors and cover plates marked Danger.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

283

49 CFR 229.85 - Doors and cover plates marked Danger.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

284

Thick film ink chemistry  

Microsoft Academic Search

Twenty-six thick film inks from two vendors were proved for hybrid microcircuit production use. A data base of chemical information was established for all the inks to aid in future diagnostic and failure analysis activities. Efforts included both organic chemical analysis of printing vehicles and binders and inorganic chemical analysis of glass frits and electrically active phases. Analytical methods included

R. W. Gehman

1982-01-01

285

Optically thick plasmas  

Microsoft Academic Search

Experimental evidence is presented to show that plasmas are often ; optically thick. Data are included on the absorption and emission spectra of Ar ; and N plasmas produced in a plasmajet torch. These plasmas were found to be ; optically thin only at wavelengths shonter than 0.65 . (J.R.D.);

R. Tourin

1963-01-01

286

Mechanosensing of substrate thickness  

PubMed Central

Structure and function of the adherent cell depend in a crucial way on its microenvironment, including the stiffness of its substrate. It is often asserted that substrate thickness (as opposed to stiffness) plays a negligible role and therefore may be considered semi-infinite. This assertion has been recently challenged, but the characteristic length scale to consider in this regard is poorly understood. We show here that this characteristic length scale is the lateral cell size. As substrate thickness approaches the lateral dimension of the cell, the apparent stiffness of the substrate is amplified to levels much greater than the intrinsic stiffness of the substrate. This change in apparent stiffness is readily sensed by the cell, leading to changes in cell spreading area, stiffness, and contractile forces. In contrast to these responses that occur over the length of the cell, mechanosensing around an isolated point force is influenced greatly by intrinsic substrate stiffness but to a negligible extent by substrate thickness. We conclude that mechanosensing of substrate thickness is dominated in large part by traction forces spread over the lateral dimension of the cell. PMID:21230324

Lin, Yu-Chun; Tambe, Dhananjay T.; Park, Chan Young; Wasserman, Michael R.; Trepat, Xavier; Krishnan, Ramaswamy; Lenormand, Guillaume; Fredberg, Jeffrey J.; Butler, James P.

2012-01-01

287

Intro to Plate Tectonic Theory  

NSDL National Science Digital Library

This website from PBS provides information about the plate tectonics, the theory that the Earth's outer layer is made up of plates, which have moved throughout time. The four types of plate boundaries are described and illustrated with animations. The first page of plate tectonics also provides a plate tectonics activity and information about related people and discoveries.

2008-05-28

288

Plate Tectonics Prof. Thomas Herring  

E-print Network

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

Herring, Thomas

289

Influence of filter thickness on PESA calibration  

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

290

Population-based design of mandibular fixation plates with bone quality and morphology considerations.  

PubMed

In this paper we present a new population-based implant design methodology, which advances the state-of-the-art approaches by combining shape and bone quality information into the design strategy. The method may enhance the mechanical stability of the fixation and reduces the intra-operative in-plane bending which might impede the functionality of the locking mechanism. The computational method is presented for the case of mandibular locking fixation plates, where the mandibular angle and the bone quality at screw locations are taken into account. The method automatically derives the mandibular angle and the bone thickness and intensity values at the path of every screw from a set of computed tomography images. An optimization strategy is then used to optimize the two parameters of plate angle and screw position. The method was applied to two populations of different genders. Results for the new design are presented along with a comparison with a commercially available mandibular locking fixation plate (MODUS() TriLock() 2.0/2.3/2.5, Medartis AG, Basel, Switzerland). The proposed designs resulted in a statistically significant improvement in the available bone thickness when compared to the standard plate. There is a higher probability that the proposed implants cover areas of thicker cortical bone without compromising the bone mineral density around the screws. The obtained results allowed us to conclude that an angle and screw separation of 129 and 9mm for females and 121 and 10mm for males are more suitable designs than the commercially available 120 and 9mm. PMID:23053302

Bousleiman, Habib; Iizuka, Tateyuki; Nolte, Lutz-Peter; Reyes, Mauricio

2013-02-01

291

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

E-print Network

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 ...

Xu, Zhiguang

292

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

293

Improved compression buckling for rectangular composite plates by stiffness tailoring  

NASA Technical Reports Server (NTRS)

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.

Biggers, Sherrill B.; Srinivasan, Sundar

1991-01-01

294

COMPPAP - COMPOSITE PLATE BUCKLING ANALYSIS PROGRAM (UNIX VERSION)  

NASA Technical Reports Server (NTRS)

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.

Smith, J. P.

1994-01-01

295

40 CFR 426.46 - Pretreatment standards for new sources.  

Code of Federal Regulations, 2011 CFR

...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...

2011-07-01

296

40 CFR 426.46 - Pretreatment standards for new sources.  

Code of Federal Regulations, 2012 CFR

...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...

2012-07-01

297

40 CFR 426.44 - Pretreatment standards for existing sources.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

298

40 CFR 426.44 - Pretreatment standards for existing sources.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

299

40 CFR 426.46 - Pretreatment standards for new sources.  

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

300

Uranium Plate Test Stack: Test of CC Design  

SciTech Connect

A test needed to be set up to determine if it is possible, using different pressures and button spacings, to successfully flatten the uranium plates, and test the current CC design. To run the test a series of 12 plates was set up in a cryogenic bath with bellows at one end of the bath to apply pressure to the stack. Each plate was numbered for identification and this can be noted on figure one, and plate flatness data. To determine the flatness of each uranium plate before stacking a number of measurements were taken. These included: (1) overall dimensions of each plate; (2) thickness of each plate at different locations on the plate; (3) ultrasound thickness test; (4) dial gauge front contour; and (5) dial gauge back contour. The plates were stacked as indicated in figure 1. they were randomly oriented, and orientation of each is noted in figure 1. The Fermilab number will always be located on the front of the plate. the locations noted on figure 1 are the locations of the Fermi-number. The plates were compressed then flooded with liquid nitrogen. Compression using 20 PSI in the bellows. Gap measurements could now be taken. This was accomplished by using a set of rods of known diameters. A rod was inserted into the gap, if it did not fit the next size smaller rod was inserted, thereby giving a range for gap width. For a rod to fit in the gap it was inserted and moved back and forth in the east-west direction. If the rod hung up at any point in the gap it was considered to large for the gap. The pressure was lowered to 1 psi in the bellows and the measurements repeated; the pressure was brought back to the original 20 psi and measurements were again taken.

Stepanek, G.; /Fermilab

1985-12-18

301

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

E-print Network

Author's personal copy Plate tectonic reconstructions with continuously closing plates$ Michael are downwellings controlled by the history of subduction, that these mantle down- wellings push hot mantle

Bower, Dan J.

302

Plate forming and break down pizza box  

DOEpatents

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.

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

1992-01-01

303

Plate Tectonics Jigsaw  

NSDL National Science Digital Library

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.

Egger, Anne

304

Mechanical forcing of the wake of a flat plate  

Microsoft Academic Search

We report experimental results of the forced wake of a thin symmetric flat plate, placed parallel to an uniform air stream, in the range of thickness-based Reynolds number 50Re e<200. External wake forcing was introduced by small harmonic oscillations of a moving flap, placed at the trailing-edge of the flat plate. When the flap remains in a fixed horizontal position,

M. Vial; L. Bellon; R. H. Hernndez

2004-01-01

305

Weldability evaluation of high tensile plates using GMAW process  

Microsoft Academic Search

High tensile plates, SAILMA-450 high impact (HI) (yield strength, 45 kg\\/mm2 minimum; ultimate tensile strength, 57 kg\\/mm2 minimum; elongation, 19% minimum; Charpy impact energy 2.0 kg.m at ?20 C minimum) were successfully developed at the Steel\\u000a Authority of India Ltd., up to 32 mm plate thickness. Since then the steel has been extensively used for the fabrication of\\u000a impellers, bridges,

R. Datta; D. Mukerjee; K. L. Rohira; R. Veeraraghavan

1999-01-01

306

Effect of Curvature on the Impact Damage Characteristics and Residual Strength of Composite Plates  

NASA Technical Reports Server (NTRS)

The results of a study of the response and failure characteristics of thin, cylindrically curved, composite plates subjected to low-speed impact damage are presented. The results indicate that the plate radius and the plate thickness are important structural parameters that influence the nonlinear response of a plate for a given amount of impact energy. Analytical and experimental contact-force results are compared for several plates and the results correlate well. The impact-energy levels required to cause damage initiation and barely visible impact damage are a function of the plate radius for a given plate thickness. The impact-energy levels required to initiate impact damage for plates with a certain range of radii are greater than plates with other radii. The contact-force results corresponding to these impact-energy levels follow a similar trend. Residual strength results for plates with barely visible impact damage suggest that the compression-after-impact residual strength is also a function of plate radius. The residual strength of impact-damaged flat plates appears to be lower than the residual strength of the corresponding cylindrically curved plates.

Ambur, Damodar R.; Starnes, James H., Jr.

1998-01-01

307

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.

308

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.

309

Curved-Channel Microchannel Plates  

NASA Astrophysics Data System (ADS)

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

Laprade, Bruce; Cortez, Jose

1984-01-01

310

Lithospheric strength and its relationship to the elastic and seismogenic layer thickness  

E-print Network

Lithospheric strength and its relationship to the elastic and seismogenic layer thickness A 2003 Abstract Plate flexure is a phenomenon that describes how the lithosphere responds to long of the lithosphere, Te. In the oceans, Te is the range 2^50 km and is determined mainly by plate and load age

Watts, A. B. "Tony"

311

Gold thick film conductors  

Microsoft Academic Search

Conventional thick film conductors rely for their adhesion on the formation of a glassy layer which keys them both chemically\\u000a and mechanically to the substrate surface. A newer type of conductor contains no glass frit but is reactively-bonded to the\\u000a substrate, resulting in different properties which may be advantageous for certain applications. This article is based upon\\u000a a contribution presented

M. V. Coleman; G. E. Gurnett

1977-01-01

312

Conversion of 45 rotated X-cut KNbO3 plates to Y-cut plates by compression  

Microsoft Academic Search

Potassium niobate (KNbO3) single crystals with a pseudo-cubic structure exhibit very high piezoelectric coupling factors for thickness-extensional modes and surface acoustic waves, kt and kSAW. To obtain a better understanding of domain-behavior with a stress, conversion of high-kt 45 rotated X-cut plates of KNbO3 to high-kSAW Y-cut plates was attempted by applying a compressive force obliquely to the major surface

Kiyoshi NAKAMURA; Norihiro CHIBA; Shigeo ITO

2004-01-01

313

Growth Plate Injuries  

MedlinePLUS

... knee or ankle. Prognosis is poor, since premature stunting of growth is almost inevitable. A newer classification, ... and growth. Will the Affected Limb of a Child With a Growth Plate Injury Still Grow? Most ...

314

Half Wave Plate Program  

NSDL National Science Digital Library

The Half Wave Plate program displays the effect of a half wave plate on an incident electromagnetic wave. The default electromagnetic wave is plane polarized but this polarization can be changed by specifying the components of the waves Jones vector using the input fields. The slider can be used to rotate the half wave plate to change its orientation. Half Wave Plate is an Open Source Physics program written for the teaching of optics. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the optics_halfwave.jar file will run the program if Java is installed. Other optics programs are also available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Optics.

Simov, Kiril; Christian, Wolfgang

2008-05-20

315

Quarter Wave Plate Program  

NSDL National Science Digital Library

The Quarter Wave Plate program displays the effect of a quarter wave plate on an incident electromagnetic wave. The default electromagnetic wave is plane polarized but this polarization can be changed by specifying the components of the waves Jones vector using the input fields. The slider can be used to rotate the quarter wave plate to change its orientation. Quarter Wave Plate is an Open Source Physics program written for the teaching of optics. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the optics_quarterwave.jar file will run the program if Java is installed. Other optics programs are also available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Optics.

Simov, Kiril; Christian, Wolfgang

2008-05-20

316

How Plates Move  

NSDL National Science Digital Library

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

317

Positive battery plate  

NASA Technical Reports Server (NTRS)

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.

Rowlette, John R. (Inventor)

1985-01-01

318

Normal-Pressure Tests of Circular Plates with Clamped Edges  

NASA Technical Reports Server (NTRS)

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.

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

1942-01-01

319

Status of high-density fuel plates fabrication  

SciTech Connect

Progress has continued on the fabrication of fuel plates with fuel zone loadings approaching 9gU/cm{sup 3}. Using Hot Isostatic Pressing (HIPping) successful diffusion bonds have been made with 110 Al and 6061 Al alloys. These bonds demonstrated the most critical processing step for proof-of-concept hardware. Two types of prototype highly-loaded fuel plates have been fabricated. First, a fuel plate in which 0.030 in. (0.76 mm) uranium compound wires are bonded within an aluminum cladding and second, a dispersion fuel plate with uniform cladding and fuel zone thickness. The successful fabrication of these fuel plates derives from the unique ability of the HIPping process to produce diffusion bonds with minimal deformation. 2 refs., 3 figs.

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

1989-09-01

320

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

NASA Astrophysics Data System (ADS)

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 75C. 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 70C and 110C 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.

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

2011-04-01

321

The use of split-thickness dermal grafts to resurface full thickness skin defects.  

PubMed

Coverage of large burns may be difficult when skin graft donor sites are limited. This study explored the use of the split-thickness dermal graft (STDG), as an alternative to the standard split-thickness skin graft (STSG). STSGs and STDGs were compared experimentally by their ability to resurface full thickness skin defects in a pig model. Both types of grafts were harvested from the backs of six pigs and placed on full thickness wounds. From the same donor site a 0.012in. thick STSG and another two 0.012in. thick STDGs were harvested. Thus the deep surface of grafts measured 0.012, 0.024 and 0.036in. from the skin surface, respectively. All grafts were placed on 6cmx6cm full thickness wounds. The donor areas healed at 1 week. Epithelialization of the STDGs, was assessed by computerized planimetry, and was 100% at 4 weeks. Graft biopsies revealed that STSGs were significant thinner than STDGs at 1 week (P=0.0422, 0.0135), 2 weeks (P=0.0240) and 4 weeks (P=0.0516, 0.0425). We conclude that STDGs my provide definitive coverage of full thickness skin deficits in a pig wound model. PMID:12464473

Rubis, Brent A; Danikas, Dimitrios; Neumeister, Michael; Williams, W Geoff; Suchy, Hans; Milner, Stephen M

2002-12-01

322

Analytical Studies of Thickness-Extensional Trapped Energy Mode Resonators and Transducers  

NASA Astrophysics Data System (ADS)

Partially electroded PZT-7A plates undergoing free and forced thickness-extensional trapped energy mode vibrations are treated analytically. In each problem the solution consists of a sum of the dominant plate eigensolutions for shorted electrodes in the electroded region and for zero surface charge in the unelectroded region. The driven thickness solution is also included in the electroded region in the problems of forced vibrations. Since the solution chosen automatically satisfies the differential equations of motion and the boundary conditions on the major surfaces of the plate, substitution into the appropriate variational principle of linear piezoelectricity yields integral conditions across the thickness of the plate at the edge of the electrode. In problems of free vibrations these integral conditions yield a system of homogeneous algebraic equations to which a number of auxiliary conditions may be imposed. In forced problems, a system of inhomogeneous equations results. Resonant modes of free vibrations for plates with infinite strip electrodes are determined in the frequency range between the thickness-extensional frequencies for electroded and unelectroded plates. Then by including in the solution in the unelectroded region traveling-wave modes, which carry energy away from the electroded region, forced vibrations are treated from very low frequency, where energy trapping due to a mode with complex wavenumber is exhibited, up to the thickness frequency of the unelectroded plate. Finally, the thickness solution and the plate eigensolutions for infinite plates are determined taking into account acoustic radiation into. a surrounding fluid medium, and these solutions are used in the forced problem of a transducer radiating into a fluid. *This work was supported in part by the Office of Naval Research under Contract No. N00014-76-C-0368 and by the National Science Foundation under Grant No. ECS 8024297.

Shick, Douglas V.

323

Nonlinear analysis of smart composite plate and shell structures  

E-print Network

............................54 3. 5 Vibration suppression characteristics for different smart material location ........57 3. 6 Vibration suppression times for CFRP laminated plate.......................................59 3. 7 Effect of lamina thickness on vibration... ..........................................................65 3. 10 Vibration suppression characteristics of CFRP spherical shells ( 2 10 ) for the different mode; (a) Thin shell ( 100), (b) Thick shell ( 10)...68 3. 11 Vibration suppression characteristics of CFRP spherical shells ( 2 3...

Lee, Seung Joon

2005-08-29

324

Influence of cortical bone thickness on the ultrasound velocity  

PubMed Central

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

Mandarano-Filho, Luiz Garcia; Bezuti, Marcio Takey; Mazzer, Nilton; Barbieri, Claudio Henrique

2012-01-01

325

Caribbean plate interactions  

SciTech Connect

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.

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

1993-02-01

326

Subcutaneous adipose tissue thickness alters cooling time during cryotherapy  

Microsoft Academic Search

Otte JW, Merrick MA, Ingersoll CD, Cordova ML. Subcutaneous adipose tissue thickness alters cooling time during cryotherapy. Arch Phys Med Rehabil 2002;83:1501-5. Objective: To determine if differing subcutaneous adipose thickness alters the treatment duration required to produce a standard cooling effect during cryotherapy. Design: A 4-group, between-groups comparison in which the independent variable was skinfold thickness (0[ndash ]10mm, 11[ndash ]20mm,

Jeffrey W. Otte; Mark A. Merrick; Christopher D. Ingersoll; Mitchell L. Cordova

2002-01-01

327

Thick Lens Model  

NSDL National Science Digital Library

The EJS Thick Lens model allows the user to simulate a lens (mirror) by adjusting the physical properties of a transparent (reflecting) object and observing the object's effect on a beam of light.  The user can adjust the concavity of the sides, the index of refraction and its environment, and the height and width of the object as well as the size of the incident light and the horizontal position of the transparent object.  Spherical aberration can be observed at large angles. You can examine and modify this simulation if you have Ejs installed by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. Ejs Thiuck Lens model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ntnu_optics_ThickLens.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for optics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Hwang, Fu-Kwun

2008-11-02

328

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.

329

India Plate Motion, Intraplate deformation and Plate Boundary Processes (Invited)  

NASA Astrophysics Data System (ADS)

We use GPS-measured velocities to geodetically constrain India plate motion, intraplate strain, and examine plate boundary deformation and plate interactions around the India plate. Our solution includes 15 GPS velocities from continuously recording stations from within the stable India plate interior that are used to estimate angular velocity of the India plate with respect to its neighbors. We test a two-plate India system divided along the topographically prominent Narmada Son Lineament and find this scenario to be significant only to 89%. Dense station coverage along the Himalayan range front allows us to rigorously test boundary parameterizations and develop a preferred plate boundary model. In our preferred model the Himalayan Range Front accumulates ~50% of the India-Eurasia convergence with as much as 18 mm/yr of slip accumulation along some segments. We compare earthquake slip vector orientations with predicted divergence directions from our preferred model along the India-Somalia plate boundary. We see good agreement between predicted plate directions from our preferred model and the seismological data. Deviations between our model and the slip vectors highlight areas of diffuse oceanic deformation along the plate boundary. We estimate convergence vectors for the relative plate pairs along the Sumatra subduction zone. We test for the transition between Australian plate convergence and India plate convergence along the Sumatra subduction zone and refine the estimated motion of the Burman sliver plate.

Apel, E. V.; Burgmann, R.; Banerjee, P.

2010-12-01

330

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

SciTech Connect

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

Lee, S.Y.; Ou, J.J. [National Cheng Kung Univ. Tainan (Taiwan, Province of China). Dept. of Mechanical Engineering

1993-12-31

331

A New Exponential Plate Theory for Laminated Composites under Cylindrical Bending  

NASA Astrophysics Data System (ADS)

This paper presents a new laminated plate theory for cylindrical bending of laminated plates. The new theory assumes that inplane displacements vary exponentially through plate thickness. The accuracy of the new theory is examined for symmetric/antisymmetric cross-ply, angle-ply and unsymmetric laminates under cylindrical bending. The numerical results show that the new theory provides displacements and stresses very accurately as compared to three-dimensional elasticity solutions. In particular, transverse shear stresses obtained from constitutive equations are predicted very accurately. The results are compared with those obtained from the first-order shear deformation plate theory and the classical laminated plate theory.

Park, Jungsun; Lee, Soo-Yong

332

Got Standards? "Got Standards?"  

E-print Network

in order to bring harmony to global standards for international trade. Enter ISO 9000. The Basics In order to fully understand the concept of ISO 9000, it is very important to have a good idea of what a standard is for Standards. ISO 9000 standards are sometimes called "generic management system standards." "Generic

Vardeman, Stephen B.

333

49 CFR 229.85 - High voltage markings: doors, cover plates, or barriers.  

Code of Federal Regulations, 2013 CFR

...Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System 229.85 High voltage markings: doors, cover plates, or barriers. All...

2013-10-01

334

49 CFR 229.85 - High voltage markings: doors, cover plates, or barriers.  

Code of Federal Regulations, 2012 CFR

...Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System 229.85 High voltage markings: doors, cover plates, or barriers. All...

2012-10-01

335

Asymptotic behavior of a flat plate wake  

NASA Technical Reports Server (NTRS)

An experimental study has been conducted to investigate the far-field, self-similar properties of a flat plate wake. A plane turbulent wake was generated at the trailing edge of a smooth splitter plate separating two legs of a Mixing Layer Wind Tunnel, with both initial boundary layers tripped. For the present study, both legs were operated at a free-steam velocity in the test section of 15 m/s, giving a Reynolds number based on wake momentum thickness of about 1750. Single profile measurements were obtained at five streamwise locations using a Pitot probe for the mean velocity measurements and a single cross-wire probe for the turbulence data, which included statistics up to third order. The mean flow data indicated a self-similar behavior beyond a streamwise distance equivalent to about 350 wake momentum thicknesses. However, the turbulence data show better collapse beyond a distance equivalent to about 500 momentum thicknesses, with all the measured peak Reynolds stresses achieving constant, asymptotic levels. The asymptotic mean flow behavior and peak primary stress levels agree well with theoretical predictions based on a constant eddy viscosity model. The present data also agree reasonably well with previous measurements, of which only one set extends into the self-similar region. Detailed comparisons with previous data are presented and discussed in this report.

Weygandt, James H.; Mehta, Rabindra D.

1989-01-01

336

Polar Plate Theory for Orthogonal Anisotropy  

NASA Technical Reports Server (NTRS)

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.

Bailey, Michelle D.; Bower, Mark V.

2000-01-01

337

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

NASA Astrophysics Data System (ADS)

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).

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, Jos Carlos; Lassila, Antti; O'Donnell, Jim; Balsamo, Alessandro

2014-01-01

338

NET AND GROSS THICKNESS  

E-print Network

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American Stratigraphic Code). Use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U. S. Geological Survey. PP-1 TABLE OF CONTENTS

Philip H. Nelson; Wildlife Refuge; Anwr Assessment Team; U. S. Geological

339

Nitrided Metallic Bipolar Plates  

SciTech Connect

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.

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

340

Critical thickness in silicone thermosets  

E-print Network

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 ...

Deopura, Manish, 1975-

2005-01-01

341

Reproducibility of Nerve Fiber Thickness, Macular Thickness, and Optic Nerve Head Measurements Using StratusOCT  

PubMed Central

Purpose The measurement reproducibility of the third generation of commercial optical coherence tomography, OCT-3 (StratusOCT, software ver. A2, Carl Zeiss Meditec Inc., Dublin, CA) was investigated. The nerve fiber layer (NFL) thickness, macula thickness map, and optic nerve head (ONH) parameters in normal eyes were studied. Methods Ten normal subjects were imaged six times (three before and three after dilation) per day, and the series was repeated on three different days. The order of the scans before pupil dilation was randomized in each of the 3 days of scanning. After pupil dilation, the scans were also randomized in each of the 3 days of scanning. Each series was performed separately for standard-density (128 A-scans per macular and ONH image and 256 A-scans per NFL image) and high-density (512 A-scans per image for all three scan types) scanning. Results The mean macular thickness was 235 9.8 ?m. A-scan density (or image acquisition speed) had a statistically significant effect (P < 0.05) on the reproducibility of the mean macular thickness, macular volume, and a few sectors of the macular map. No significant dilation effect was found for any of the macular parameters. The best intraclass correlation coefficient (ICC; 94%) for macular scans was found for dilated high-density scanning, with an intervisit SD of 2.4 ?m and an intravisit SD of 2.2 ?m. The mean NFL thickness for standard scanning was 98 9 ?m. NFL reproducibility showed mixed results and had interactions between scan density and dilation for some parameters. For most of the NFL parameters, reproducibility was better with dilated standard-density scanning. The mean NFL thickness ICC for dilated standard scanning was 79%, with an intervisit SD of 2.5 ?m and an intravisit SD of 1.6 ?m. For the ONH analysis, the reproducibility was better for dilated standard-density scanning for almost all the parameters, except for disc area, horizontal integrated rim volume, and vertical integrated rim area, which were better before dilation. The best reproducibility was found for cup-to-disc ratio (ICC = 97%, with intervisit SD of 0.04 ?m and intravisit SD of 0.02 ?m). Conclusions StratusOCT demonstrated reproducible measurements of NFL thickness, macular thickness, and optic nerve head parameters. The best reproducibility was found for dilated standard scanning for NFL and ONH parameters and for dilated high-density scanning for macular parameters. PMID:15161831

Paunescu, Lelia A.; Schuman, Joel S.; Price, Lori Lyn; Stark, Paul C.; Beaton, Siobahn; Ishikawa, Hiroshi; Wollstein, Gadi; Fujimoto, James G.

2007-01-01

342

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.

343

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.

344

Plate Tectonics and Volcanism  

NSDL National Science Digital Library

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

345

Buckling transition and boundary layer in non-Euclidean plates  

E-print Network

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

Efi Efrati; Eran Sharon; Raz Kupferman

2009-02-17

346

Dual passband dichroic plate for X-band  

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

347

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 ...

348

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

SciTech Connect

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.

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

1995-11-01

349

A database of worldwide glacier thickness observations  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

350

Peripapillary and Macular Choroidal Thickness in Glaucoma  

PubMed Central

Purpose To compare choroidal thickness (CT) between individuals with and without glaucomatous damage and to explore the association of peripapillary and submacular CT with glaucoma severity using spectral domain optical coherence tomography (SD-OCT). Methods Ninety-one eyes of 20 normal subjects and 43 glaucoma patients from the UCLA SD-OCT Imaging Study were enrolled. Imaging was performed using Cirrus HD-OCT. Choroidal thickness was measured at four predetermined points in the macular and peripapillary regions, and compared between glaucoma and control groups before and after adjusting for potential confounding variables. Results The average ( standard deviation) mean deviation (MD) on visual fields was ?0.3 (2.0) dB in controls and ?3.5 (3.5) dB in glaucoma patients. Age, axial length and their interaction were the most significant factors affecting CT on multivariate analysis. Adjusted average CT (corrected for age, axial length, their interaction, gender and lens status) however, was not different between glaucoma patients and the control group (P=0.083) except in the temporal parafoveal region (P=0.037); nor was choroidal thickness related to glaucoma severity (r=?0.187, P=0.176 for correlation with MD, r=?0.151, P=0.275 for correlation with average nerve fiber layer thickness). Conclusions Choroidal thickness of the macular and peripapillary regions is not decreased in glaucoma. Anatomical measurements with SD-OCT do not support the possible influence of the choroid on the pathophysiology of glaucoma.

Hosseini, Hamid; Nilforushan, Naveed; Moghimi, Sasan; Bitrian, Elena; Riddle, Jay; Lee, Gina Yoo; Caprioli, Joseph; Nouri-Mahdavi, Kouros

2014-01-01

351

Explosion Bulge Testing of Australian HY-80 Steel Plate.  

National Technical Information Service (NTIS)

This report describes the program of explosion bulge testing of 50 mm thick Australian sourced HY-80 steel plate, supplied by Bunge Industrial Steels P/L to Industry Development Branch (NSW Region) to specification MIL-S-16216H (SHIPS). The testing was un...

B. F. Dixon, J. C. Ritter

1985-01-01

352

Three-dimensional analysis of transient thermal stresses in functionally graded plates  

E-print Network

-7683(03)00361-5 #12;is to use functionally graded materials (FGMs). In a functionally graded (FG) plate, the volumeThree-dimensional analysis of transient thermal stresses in functionally graded plates Senthil S. Material properties are taken to be analytical functions of the thickness coordinate. The uncoupled quasi

Vel, Senthil

353

The Finite Element Analysis of Quartz Crystal Resonators with Nonlinear Plate Equations  

E-print Network

The Finite Element Analysis of Quartz Crystal Resonators with Nonlinear Plate Equations Ji Wang1, dujianke, wanglihong}@nbu.edu.cn, yyong@rci.rutgers.edu Abstract--The finite element analysis of quartz for typical thickness-shear vibrations of quartz crystal plates. While linear finite element analysis

Wang, Ji

354

The ballistic properties of tool steel as a potential improvised armour plate  

Microsoft Academic Search

The ballistic behaviour of a 0.95 weight per cent carbon tool steel against 7.62 mm ball and armour piercing bullets was investigated in the unwelded and welded condition. Gross cracking occurred at plate hardnesses of 510 HV and greater. The mode of perforation for tool steel of hardness 380 H V, which was petalling for 5 mm thick plates and

M. R. Edwards; A. Mathewson

1997-01-01

355

Manufacturing of composite violin top plates and design of composite tailpieces By : Maxime Beaulieu  

E-print Network

. Manufacturing Steps Conclusions ·Carbon fiber/epoxy can produce parts much lighter than spruce wood where the wood core was present. Another violin part that could benefit from composite materials then a typical 2.5mm thick spruce plate which weighs 84g but some plates were made heavy on purpose

Barthelat, Francois

356

Weldability characteristics of shielded metal arc welded high strength quenched and tempered plates  

Microsoft Academic Search

High strength, quench and tempered (Q&T) plates having yield strength of a minimum of 670 MPa and conforming to SA 517 Gr.\\u000a F specification were successfully developed at Rourkela Steel Plant in plates up to 40 mm thickness. The plates are used extensively\\u000a for the fabrication of impellers, penstocks, excavators, dumpers, and raw material handling devices, where welding is an

R. Datta; D. Mukerjee; S. Jha; K. Narasimhan; R. Veeraraghavan

2002-01-01

357

Waterway Ice Thickness Measurements  

NASA Technical Reports Server (NTRS)

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.

1978-01-01

358

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.

359

Plate Tectonic Movement Visualizations  

NSDL National Science Digital Library

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

2007-04-15

360

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.

361

elementsair ceramic plate  

E-print Network

and earth to generate electrical power [7, 8]. Temperature differences of about -0.35° to 0.7°C werearth elementsair L ceramic plate Thermoelectric Module Construction for Low Temperature Gradient Power Generation Y. Meydbray, R. Singh, Ali Shakouri University of California at Santa Cruz, Electrical

362

Liquid film thickness measurement by two-line TDLAS  

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

363

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.

364

The magma ocean as an impediment to lunar plate tectonics  

NASA Technical Reports Server (NTRS)

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.

Warren, Paul H.

1993-01-01

365

Design of Fracture Fixation Plate for Necessary and Sufficient Bone Stress Shielding  

NASA Astrophysics Data System (ADS)

The objective of treating the fractured bone is to achieve painless functioning of the bone and undisturbed healing at the fracture. Internal fixation by stiff bone-plate is one of the standard methods to achieve these objectives. Recently, there is considerable interest in the usage of compliant plates to enhance bone healing with reduced stress shielding. Herein, first an analytical solution is developed to determine screw forces in the bone-plate assembly that conforms the plate and the bone under bending load. Based on the analytical calculations, an optimal fixator plate selection criterion for necessary and sufficient stress shielding is proposed. Second, effectiveness of employing a non-homogeneous stiffness graded (SG) plate rather than a homogeneous stainless steel (SS) plate for stress shielding is investigated using a finite element method. It is found that stress shielding on bone by SG plate is less compared to SS plate.

Ramakrishna, Kotlanka; Sridhar, Idapalapati; Sivashanker, Sathiamoorthy; Khong, Kok Sun; Ghista, Dhanjoo N.

366

Thick films of X-ray polycrystalline mercuric iodide detectors  

Microsoft Academic Search

Polycrystalline HgI2 thick film detectors are among the leading semiconductor materials to be used as direct converters in X-ray digital radiography. Their properties along with a survey of the properties of alternative materials, such as PbI2 or A-Se, will be given. The preparation of HgI2 detector plates, both by direct evaporation (Physical vapor deposition, (PVD)) and by binding the individual

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

2001-01-01

367

Plating of patella fractures: techniques and outcomes.  

PubMed

Operative treatment of displaced patella fractures with tension band fixation remains the gold standard, but is associated with a significant rate of complications and symptomatic implants. Despite the evolution of tension band fixation to include cannulated screws, surprisingly little other development has been made to improve overall patient outcomes. In this article, we present the techniques and outcomes of patella plating for displaced patella fractures and patella nonunions. PMID:24343252

Taylor, Benjamin C; Mehta, Sanjay; Castaneda, Joaquin; French, Bruce G; Blanchard, Chris

2014-09-01

368

Plate Puzzle Page 1 of 20 Plate Puzzle 1  

E-print Network

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

Benitez-Nelson, Claudia

369

Accurate Simulation of Acoustic Emission Sources in Composite Plates  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

370

Analytical modeling and vibration analysis of internally cracked rectangular plates  

NASA Astrophysics Data System (ADS)

This study proposes an analytical model for nonlinear vibrations in a cracked rectangular isotropic plate containing a single and two perpendicular internal cracks located at the center of the plate. The two cracks are in the form of continuous line with each parallel to one of the edges of the plate. The equation of motion for isotropic cracked plate, based on classical plate theory is modified to accommodate the effect of internal cracks using the Line Spring Model. Berger's formulation for in-plane forces makes the model nonlinear. Galerkin's method used with three different boundary conditions transforms the equation into time dependent modal functions. The natural frequencies of the cracked plate are calculated for various crack lengths in case of a single crack and for various crack length ratio for the two cracks. The effect of the location of the part through crack(s) along the thickness of the plate on natural frequencies is studied considering appropriate crack compliance coefficients. It is thus deduced that the natural frequencies are maximally affected when the crack(s) are internal crack(s) symmetric about the mid-plane of the plate and are minimally affected when the crack(s) are surface crack(s), for all the three boundary conditions considered. It is also shown that crack parallel to the longer side of the plate affect the vibration characteristics more as compared to crack parallel to the shorter side. Further the application of method of multiple scales gives the nonlinear amplitudes for different aspect ratios of the cracked plate. The analytical results obtained for surface crack(s) are also assessed with FEM results. The FEM formulation is carried out in ANSYS.

Joshi, P. V.; Jain, N. K.; Ramtekkar, G. D.

2014-10-01

371

North American plate dynamics  

NASA Technical Reports Server (NTRS)

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.

Richardson, Randall M.; Reding, Lynn M.

1991-01-01

372

Microchannel plate streak camera  

DOEpatents

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.

Wang, C.L.

1984-09-28

373

Microchannel plate streak camera  

DOEpatents

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.

Wang, Ching L. (Livermore, CA)

1989-01-01

374

Microchannel plate streak camera  

DOEpatents

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.

Wang, C.L.

1989-03-21

375

Interpolating Mean Rainfall Using Thin Plate Smoothing Splines  

Microsoft Academic Search

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

M. F. Hutchinson

1995-01-01

376

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

SciTech Connect

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

Moore, D.M.

1980-03-01

377

Effects of transverse shearing flexibility on the postbuckling of plates loaded by inplane shear  

NASA Technical Reports Server (NTRS)

This paper presents buckling and postbuckling results for plates loaded by inplane shear. The buckling results have been plotted to show the effects of thickness on the stress coefficient for aluminum plates. Results are given for various length-to-width ratios. Postbuckling results for thin plates with transverse shearing flexibility are compared to results from classical theory. The problems considered are the postbuckling response of plates in shear made of aluminum and of a + or - 45 deg graphite-epoxy laminate. Thus the materials are isotropic and orthotropic, respectively. The plates are considered to be long with side edges simply supported, with various inplane edge conditions, and the plates are subject to a constant shearing displacement along the side edges. Characteristic curves presenting the average shear stress resultant as a function of the applied displacement are given. These curves indicate that change in inplane edge conditions influence plate postbuckling stiffness and that transverse shearing is important in some cases.

Stein, Manuel

1987-01-01

378

Perforated plates for cryogenic regenerators and method of fabrication  

DOEpatents

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.

Hendricks, J.B.

1994-03-29

379

Perforated plates for cryogenic regenerators and method of fabrication  

DOEpatents

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.

Hendricks, John B. (Huntsville, AL)

1994-01-01

380

Flutter of a rectangular plate?  

Microsoft Academic Search

We address theoretically the linear stability of a variable aspect ratio, rectangular plate in an uniform and incompressible axial flow. The flutter modes are assumed to be two-dimensional but the potential flow is calculated in three dimensions. For dierent values of aspect ratio, two boundary conditions are studied: a clamped- free plate and a pinned-free plate. We assume that the

Christophe Eloy; Claire Souilliez; Lionel Schouveiler

2006-01-01

381

Warm Working of Armor Plate.  

National Technical Information Service (NTIS)

Taking advantage of warm working to improve the toughness of armor plate requires that the plates be able to be rolled on present day mills. Calculations indicated that a 50 inch wide steel plate with hardnesses in excess of 400 BHN could not be rolled th...

E. J. Ripling, N. N. Breyer, R. P. O'Shea

1967-01-01

382

Vibration analysis of folded plates  

Microsoft Academic Search

The finite element-transfer matrix method (FETMM) is used to study the natural frequencies of folded plate structures. The FETMM used is based on combining the stiffness and mass matrices of each flat plate element in one strip to establish the transfer matrix relation between the left side and right side of a folded strip. The cantilever folded plate or supported

W. H. Liu; C. C. Huang

1992-01-01

383

Lesson 3. Plate Tectonics Overview  

E-print Network

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

Chen, Po

384

Chest wall thickness measurements of the LLNL and JAERI torso phantoms for germanium detector counting  

SciTech Connect

The Lawrence Livermore National Laboratory and Japanese Atomic Energy Research Institute torso phantoms were developed to calibrate lung counting systems that are used to estimate plutonium and other radionuclides deposited in the lung. Originally, low energy photon counting systems consisted of phoswich detectors. The average chest wall thicknesses and individual measurement points of the Lawrence Livermore National Laboratory phantom and its overlay plates in the regions covered by these detectors were provided by the manufacturer. Germanium detectors are of a different size and are placed in different locations on the phantom so that the manufacturer`s data are no longer applicable for the locations of the germanium detectors on the phantom. The Human Monitoring Laboratory has re-evaluated the chest wall thickness of both the Lawrence Livermore National Laboratory and Japanese Atomic Energy Research Institute phantoms and their overlay plates for its germanium lung counting system. The measurements were made in the upper right, lower right, upper left, and lower left positions on the phantom`s torso plate above the lungs. The effective chest wall thicknesses (17 keV) for the Lawrence Livermore National Laboratory torso plate are 1.46 cm, 1.43 cm, 1.66 cm, 1.48 cm, respectively. The manufacturer`s quoted average effective chest wall thickness for a pair of phoswich detectors is 1.63 cm. The measured effective chest wall thicknesses (17 keV) for the JAERI`s torso plate are 1.76 cm, 2.15 cm, 1.79 cm, 2.15 cm, respectively. The manufacturer`s quoted average chest wall thickness for an unspecified region of the chest is 1.50 cm. This paper presents effective chest wall thickness data for the phantoms with and without their overlay plates at 17 keV, 60 keV, 200 keV and 1,500 keV. 13 refs., 2 figs., 4 tabs.

Kramer, G.H.; Hauck, B.M. [Human Monitoring Lab., Ottawa, Ontario (Canada)

1997-11-01

385

Flexural Thickness Variations of the Maracaibo Block  

NASA Astrophysics Data System (ADS)

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: Mrida Andes (MA), Perij 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 Bocon 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.

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

2013-05-01

386

The thickness of the ventral midline of the spinal cord in human embryos during the fifth week.  

PubMed

The thickness of the ventral midline of the spinal cord was determined in 9 human embryos aged five weeks (developmental stages 13-15). This part of the spinal cord consists of floor plate, mantle and marginal layers. The floor plate ependymal cells form pseudostratified columnar epithelium. The thickness of the investigated structure varied from 20 to 50 micrometers at different levels of the spinal cord. PMID:18828103

Wo?niak, W; Lupicka, J; Sroka, A; Bruska, M; Pytel, A

2008-08-01

387

Panel flutter characteristics of sandwich plates with CNT reinforced facesheets using an accurate higher-order theory  

NASA Astrophysics Data System (ADS)

In this paper, the flutter characteristics of sandwich panels with carbon nanotube (CNT) reinforced face sheets are investigated using QUAD-8 shear flexible element developed based on higher-order structural theory. The formulation accounts for the realistic variation of the displacements through the thickness, the possible discontinuity in the slope at the interface, and the thickness stretch affecting the transverse deflection. The in-plane and rotary inertia terms are also included in the formulation. The first-order high Mach number approximation to linear potential flow theory is employed for evaluating the aerodynamic pressure. The solutions of the complex eigenvalue problem, developed based on Lagrange's equation of motion are obtained using the standard method for finding the eigenvalues. The accuracy of the present formulation is demonstrated considering the problems for which solutions are available. A detailed numerical study is carried out to bring out the efficacy of the higher-order model over the first-order theory and also to examine the influence of the volume fraction of the CNT, core-to-face sheet thickness, the plate thickness and the aspect ratio, damping and the temperature on the flutter boundaries and the associated vibration modes.

Sankar, A.; Natarajan, S.; Haboussi, M.; Ramajeyathilagam, K.; Ganapathi, M.

2014-10-01

388

Trans-iliosacral plating for vertically unstable fractures of sacral spine associated with spinopelvic dissociation: A cadaveric study  

PubMed Central

Background: The treatment algorithm for sacral fracture associated with vertical shear pelvic fracture has not emerged. Our aim was to study a new approach of fixation for comminuted and vertically unstable fracture pattern with spinopelvic dissociation to overcome inconsistent outcome and avoid complications associated with fixations. We propose fixation with well-contoured thick reconstruction plate spreading across sacrum from one iliac bone to another with fixation points in iliac wing, sacral ala and sacral pedicle on either side. Present biomechanical study tests the four fixation pattern to compare their stiffness to vertical compressive forces. Materials and Methods: Dissection was performed on human cadavers through posterior midline paraspinal approach elevating erector spinae from insertion with two flaps. Feasibility of surgical exposure and placement of contoured plate for fixation was evaluated. Ten age and sex matched computed tomography scans of pelvis with both hips were obtained. Reconstructions were performed with advantage windows 4.2 (GE Light Speed QX/I, General Electric, Milwaukee, WI, USA). Using the annotation tools, direct digital CT measurement (0.6 mm increments) of three linear parameters was carried out. Readings were recorded at S2 sacral level. Pelvic CT scans were extensively studied for entry point, trajectory and estimated length for screw placement in S2 pedicle, sacral ala and iliac wing. Readings were recorded for desired angulation of screw in iliac wing ala of sacrum and sacral pedicle with respect to midline. The readings were analyzed by the values of mean and standard deviation. Biomechanical efficacy of fixation methods was studied separately on synthetic bone. Four fixation patterns given below were tested to compare their stiffness to vertical compressive forces: 1) Single S1 iliosacral screw (7.5 mm cancellous screw), 2) Two S1 and S2 iliosacral screws, 3) Isolated trans-iliosacral plate, 4) Trans-iliosacral plate + single S1 iliosacral screw. Statistical Analysis: Mean of desired angulation for inserting screws and percentage of displacement on biomechanical testing was evaluated. Results: Mean angulations for inserting sacral pedicel were 12.3 (SD 2.7) convergent to midline and divergent of 14 (SD 2.3) for sacral ala screw and 23 (SD 4.9) for iliac wing screw. All screws needed to be inserted at an angle of 90 to sacral dorsum to avoid violation of root canals. Cross headed displacement across fracture site was measured and plotted against the applied vertical shear load of 300 N in five cycles each for all the four configurations. Also, the force required for cross headed displacement of 2.5 mm and 5 mm was recorded for all configurations. Transmitted load across both ischial tuberosities was measured to resolve unequal distribution of forces. Taking one screw construct (configuration 1) as standard base reference, trans-iliosacral plate construct (configuration 3) showed equal rigidity to standard reference. Two screw construct (configuration 2) was 12% stronger and trans-iliosacral plate (configuration 4) with screw was 9% stronger at 2.5 mm displacing on 300 N force, while it showed 30% and 6%, respectively, at 5 mm cross-headed displacement. Conclusions: Trans-iliosacral plating is feasible anatomically, biomechanically and radiologically for sacral fractures associated with vertical shear pelvic fractures. Low profile of plate reduces the risk of hardware prominence and decreases the need for implant removal. Also, the fixation pattern of plate allows to spare mobile lumbosacral junction which is an important segment for spinal mobility. Biomechanical studies revealed that rigidity offered by plate for cross headed displacement across fracture site is equal to sacroiliac screws and further rigidity of construct can be increased with addition of one more screw. There is need for precountered thicker plate in future. PMID:22719112

Padalkar, Pravin; Pereira, Barry P; Kathare, Ambadas; Sun, Khong Kok; Kagda, Fareed; Joseph, Thambiah

2012-01-01

389

Non-standard subduction of gabbroic lithosphere into gabbroic mush ocean  

NASA Astrophysics Data System (ADS)

Plate tectonics efficiently transports heat on the modern Earth. It will cease about 1 billion years in the future when the mantle becomes too cold to melt extensively at ridge axes. Conversely, the high temperature of the Earth's interior produced thick oceanic crust on the early Earth, which made standard subduction difficult. Yet a non-standard form of subduction may have occurred. The Earth self-organized so that the upper about 100 km was gabbroic mush, capped by gabbroic lithosphere (away from continents). That is, ridge axes resembled very thick modern fast ridge mush chambers. The gabbroic lithosphere, once aged, cooled, and thickened, subducted into the mush. It transformed to eclogite at about 100 km depth and continued to descend. The need for gabbro to transform to dense eclogite buffered the thickness of the mush to 100 km. The mantle temperature was comparable to that of modern hotspots, 200-300 K above modern MORB sources. Melting of peridotite below 100-km depth determined the input composition to the gabbroic layer. The Earth may have alternated between episodes of mush ocean and intervening plate tectonic episodes where the interior heated up from radioactivity. Non-standard subduction is very efficient at generating Si-rich melts because the wedge above the slab is gabbroic mush rather than peridotite. Refractory olivine-rich continental lithosphere may have formed above the slab at greater depths. This hypothesis provides for the coexistence of structures resembling those formed at plate boundaries with voluminous arc magmas formed by direct hydrous melting of sources with gabbroic composition. It also provides for global periods of rapid tectonics and heat loss.

Sleep, N. H.

2006-12-01

390

Mantle Convection with Strong Plates and the Thermal Evolution of the Earth  

NASA Astrophysics Data System (ADS)

We present an analytic model for thermal convection with a finite-strength plate and a depth-dependent viscosity. The model differentiates between the lithosphere and the overall convective cell and has distinct energy balance equations for both. The model yields the plate velocity, plate thickness and heat flow, as well as the depth-dependent flow profile for the convective cell. The introduction of a strong plate has a significant impact on the behavior of the system. We demonstrate that the dominant plate driving force depends not only on the material properties of the mantle and lithosphere, but also on the velocity of the plate. Multiple solutions for the plate velocity are possible with three solution branches (fast, intermediate, and slow) representing three distinct modes of thermal convection with plate tectonics. The pressence of an asthenosphere above a high viscosity lower mantle modifies the dynamics by altering the plate-mantle coupling. Lowering the asthenospheric viscosity, relative to the lower mantle, can promote plate motion by providing a lubricating layer. However, a very low viscosity layer beneath a strong plate can inhibit plate motion and produce sluggish lid convection. The model allows us to explore a new class of thermal evolution models for the Earth that incorporate transitions between different mantle convection regimes.

Crowley, J. W.; O'Connell, R. J.

2011-12-01

391

Bending Behavior of Simply Suppoted Metallic Sandwich Plates with Dimpled Cores  

NASA Astrophysics Data System (ADS)

Metallic sandwich plates are lightweight structural materials with load-bearing and multi-functional characteristics. Previous analytic studies have shown that the bendability of these plates increases as the thickness decreases. Due to difficulty in the manufacture of thin sandwich plates, dimpled cores (structures called egg-box cores) are employed as a sandwich core. High-precision dimpled cores are easily fabricated in a sectional forming process. The cores are then bonded with skin sheets by multi-point resistance welding. The bending characteristics of simply supported plates were observed by the defining measure, including the radius ratio of the small dimple, the thickness of a sandwich plate, and the pattern angle (0/90, 45). Experimental results revealed that sandwich plates with a thickness of 2.2 mm and a pattern angle of 0/90 showed good bendability as the punch stroke under a collapse load was longer than other cases. In addition, the gap between attachment points was found to be an important parameter for the improvement of the bendability. Finally, sandwich plates with dimpled cores were bent with a radius of curvature of 330 mm for the sheet thickness of 2.2 mm using an incremental bending apparatus.

Seong, Dae-Yong; Jung, Chang Gyun; Yang, Dong-Yol; Ahn, Dong Gyu

392

Syneresis and delayed detachment in agar plates  

E-print Network

Biogels made of crosslinked polymers such as proteins or polysaccharides behave as porous soft solids and store large amount of solvent. These gels undergo spontaneous aging, called syneresis that consists in the shrinkage of the gel matrix and the progressive expulsion of the solvent, which eventually leads to the gel detachment from its container. Here we report on the syneresis phenomena in agar plates that consist in Petri dishes filled with a gel mainly composed of agar. Direct observations and speckle pattern correlation analyses allow us to rationalize the delayed detachment of the gel from the sidewall of the Petri dish. The detachment time $t^*$ is mainly controlled by the gel minimum thickness $e_{min}$ along the periphery of the plate: $t^*$ increases as a robust function of $e_{min}$ that neither depends on the age of the gel nor on any previous mass loss. Time-resolved correlation spectroscopy reveals that the speckle decorrelation rate increases a few hours before $t^*$ and that the gel detachment can be anticipated. This work provides quantitative observables to predict the shelf life of agar plates and highlights the key role of the competition between the syneresis and the gel adhesion to the wall in the detachment process.

Thibaut Divoux; Bosi Mao; Patrick Snabre

2014-10-30

393

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

E-print Network

-to-thickness ratios. Keywords: Functionally graded material; thick plate; cylindrical bending; vibration. INTRODUCTION in the material. One way to overcome these adverse effects is to use "functionally graded materials" in which function- ally graded plates. Displacement functions that identically satisfy boundary conditions are used

Vel, Senthil

394

Sea ice thickness measurements - data management considerations  

NASA Astrophysics Data System (ADS)

IPY is in full swing with numerous ice stations, voyages, and autonomous systems. Thickness is a key variable being measured intensively during this period to assess the mass balance of sea ice and its rate of change under increasingly warming conditions. Within this context, quantification of sea ice thickness variability at a multiple of scales is being investigated and recorded in both hemispheres by scores of scientists from around the globe. While this measured variability will lead to new understanding of sea ice and its relationship to the global climate, variability in data structures used to record and archive these results will only lead to inconsistencies, incompatibilities, and a lack of spatiotemporal coherence. The sea ice community (small and adaptable as it is) needs to develop a consensus of critical thickness parameters and associated meta data criterion that can profit from two main sources of data gathering: operations (which usually produce high data volume with minimal analysis) and science projects (offering low data volume, but considerable analysis). Consensus between the operational and science community on key data and meta data requirements will make the difference in both the quality and volume of a long-term sea ice thickness archive. This presentation explores ways to address these issues by considering a fundamental set of protocol/format requirements when recording thickness measurements. In particular, records of the sampling rates and spatial scales, instrument type and uncertainties, etc. Essentially, we need to develop and follow a standard format for archiving sea ice thickness measurements. This does not mean "ASCII" or "CSV", rather a clearly defined parameter set which covers major scales, procedures, and algorithms used to define thickness and associated uncertainties. Efforts on this topic can be used to spearhead a white paper to circulate throughout the community to build a common set of protocols for archiving sea ice thickness from the drilled point measurement to the satellite footprint. We present this topic to stimulate discussion within both operational and research communities on how best to proceed.

Geiger, C.; Fetterer, F.; Meier, W.

2007-12-01

395

The Theory of Plate Tectonics  

NSDL National Science Digital Library

This is a brief overview of the Theory of Plate Tectonics. According to the theory, the Earth's surface layer, or lithosphere, consists of seven large and 18 smaller plates that move and interact in various ways. Along their boundaries, they converge, diverge, and slip past one another, creating the Earth's seismic and volcanic activities. These plates lie atop a layer of partly molten rock called the asthenosphere. The plates can carry both continents and oceans, or exclusively one or the other. The site also explains interaction at the plate boundaries, which causes earthquakes, volcanoes and other forms of mountain building.

396

Subduction of thick crust: the Alaska example (Invited)  

NASA Astrophysics Data System (ADS)

It is a paradigm of plate tectonics that oceanic lithosphere subducts readily, while lithosphere transporting much thicker continental crust does not. Analyses of plate buoyancy have included a variety of effects, such as eclogitization, crustal compositional stratification, and plate strength, but all lead to the conclusion that crust needs to be thinner than about 15-25 km in order to subduct. A test of this conclusion is underway in southern Alaska, where the Yakutat terrane is being driven by the Pacific plate into the Alaskan margin. Its crust is 15-30 km thick, varying along strike, with a seismic velocity structure resembling an oceanic plateau; thus it spans the predicted limit in thickness of subductable crust. In the eastern thicker part, the terrane appears to be colliding and driving orogenesis in the St. Elias-Chugach ranges, although voluminous volcanism of the Wrangell Volcanic Field may be a consequence of some crust subducting. Farther west, the Yakutat terrane is 15-20 km thick and clearly subducting beneath the Prince William Sound and Kenai Peninsula. It forms the slab subducting beneath the central Alaska Range 400 km inland. The thick crust has been imaged at all depths less than 130 km, through receiver functions, travel-time tomography, and offshore by active-source imaging, with similar structure in most images. Greater than 130 km depth the imaged crust vanishes in seismic images, consistent with predicted depths of eclogitization of weakly hydrated metagabbroic crust, and the lack of a velocity contrast between eclogite and peridotite. Lithosphere including the thick Yakutat crust gives a net buoyancy close to neutral, so its subduction will depend on other factors. The high buoyancy may be responsible for the remarkably shallow dip of the plate at depths less than 50 km, producing one of the widest seismogenic thrust zones on the planet, allowing it to host the great (Mw 9.3) 1964 Gulf of Alaska earthquake. The shallow dip may also aid in driving deformation in the Alaska Range, several hundred km inland. Analogous mountain-building may occur at other sites where oceanic plateaus or rises subduct, for example in southeast Costa Rica, or where leading edges of continents subduct, such as Timor or northern New Guinea.

Abers, G. A.; Kim, Y.; Christensen, D. H.

2013-12-01

397

Fabrication of Ordered Blue Nanostructure by Anodization of an Aluminum Plate  

NASA Astrophysics Data System (ADS)

Colors in organisms are created by chemical interactions of molecular pigments and by optical interactions of incident light with biological nanostructures. The latter classes are called structural colors and form an important component of the phenotypes of many animals and even some plants. In this paper, we report on the fabrication of an ordered blue nanostructure by the anodization of an Al plate. In the fabrication of such an ordered nanostructure by the anodization of an Al plate, ordered nanostructures with a pitch and an alumina thickness of approximately 100 nm were produced on the Al plate. The ordered nanostructures on the Al plate showed no colors. However, an ordered nanostructure deposited with a Pt thin film with a thickness of approximately 10 nm showed a blue reflection with a peak reflectivity of approximately 370 nm. We conclude that this blue nanostructure on the Al plate is caused by an interference between the Al surface and the Pt surface.

Kurashima, Yuichi; Yokota, Yoshihiko; Miyamoto, Iwao; Itatani, Taro

2007-03-01

398

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

SciTech Connect

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.

Mattas, R.F.

1990-03-01

399

Apparent thickness of Saturn's rings  

Microsoft Academic Search

The determination of the physical thickness of Saturn's rings is crucial for a better understanding of the nature, the dynamics and the evolution of a system of colliding ring particles. Ground-based observations with electronographic cameras and CCD during the transit of the earth through the ring plane in March 1980, reveal a photometric apparent thickness of 1.4 + or -

Andr Brahic; Bruno Sicardy

1981-01-01

400

Measuring Thicknesses of Wastewater Films  

NASA Technical Reports Server (NTRS)

Sensor determines when thickness of film of electrically conductive wastewater on rotating evaporator drum exceeds preset value. Sensor simple electrical probe that makes contact with liquid surface. Made of materials resistant to chemicals in liquid. Mounted on shaft in rotating cylinder, liquid-thickness sensor extends toward cylinder wall so tip almost touches. Sensor body accommodates probe measuring temperature of evaporated water in cylinder.

Schubert, F. H.; Davenport, R. J.

1987-01-01

401

Free vibration analysis of magnetoelectroelastic plate resting onaPasternak foundation  

NASA Astrophysics Data System (ADS)

Free vibration of a magnetoelectroelastic plate resting on a Pasternak foundation is investigated based on Mindlin theory. The in-plane electric and magnetic fields can be ignored for plates. According to the Maxwell equation and magnetoelectric boundary condition, the variation of electric and magnetic potentials along the thickness direction of the plate is determined. Using Hamilton’s principle, the governing equations of motion for the magnetoelectroelastic plate are derived. Numerical results reveal the effects of the electric and magnetic potentials, spring and shear coefficients of the Pasternak foundation on the vibration frequency. These results may be useful in the analysis and design of smart structures constructed from magnetoelectroelastic materials.

Li, Yansong; Zhang, Jingjun

2014-02-01

402

The interfacial structure of plated copper alloy resistance spot welded joint  

NASA Astrophysics Data System (ADS)

Plated copper alloys are widely used in electron industry. The plating lay caused the farther decreasing of the welding property of copper alloys, whose intrinsic weldability was poor. In this paper, the bronze and brass specimens with nickel-tin double plating layer were joined by resistance spot welding method. The microstructure and peel strength of the joints were investigated. The experiment results show that a sandwich-like structure was obtained in the faying surface after welding, and the nickel plating layer thickness had severe effect on the reliability of the joints.

Wu, Jingwei; Zhai, Guofu; Chen, Qing; Wang, Jianqi; Ren, Gang

2008-09-01

403

Alumina plate containing photosystem I reaction center complex oriented inside plate-penetrating silica nanopores.  

PubMed

The photosynthetic photosystem I reaction center complex (PSI-RC), which has a molecular diameter of 21 nm with 100 pigments, was incorporated into silica nanopores with a 100-nm diameter that penetrates an alumina plate of 60-?m thickness to make up an inorganic-biological hybrid photocell. PSI-RCs, purified from a thermophilic cyanobacterium, were stable inside the nanopores and rapidly photoreduced a mediator dye methyl viologen. The reduced dye was more stable inside nanopores suggesting the decrease of dissolved oxygen. The analysis by a cryogenic electron spin paramagnetic resonance indicated the oriented arrangement of RCs inside the 100-nm nanopores, with their surface parallel to the silica wall and perpendicular to the plane of the alumina plate. PSI RC complex in the semicrystalline orientation inside silica nanopores can be a new type of light energy conversion unit to supply strong reducing power selectively to other molecules inside or outside nanopores. PMID:23888886

Kamidaki, Chihiro; Kondo, Toru; Noji, Tomoyasu; Itoh, Tetsuji; Yamaguchi, Akira; Itoh, Shigeru

2013-08-22

404

New Eddy Current Probe for Thickness Gauging of Conductive Materials  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

405

Sudden stretching of a four layered composite plate  

NASA Technical Reports Server (NTRS)

An approximate theory of laminated plates is developed by assuming that the extensioral and thickness mode of vibration are coupled. The mixed boundary value crack problem of a four layered composite plate is solved. Dynamic stress intensity factors for a crack subjected to suddenly applied stress are found to vary as a function of time and depend on the material properties of the laminate. Stress intensification in the region near the crack front can be reduced by having the shear modulus of the inner layers to be larger than that of the outer layers.

Sih, G. C.; Chen, E. P.

1980-01-01

406

Welded tie plate feasibility study for ITER central solenoid structure  

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

407

Dynamics of Tectonic Plates  

E-print Network

We suggest a model that describes a mutual dynamic of tectonic plates. The dynamic is a sort of stick-slip one which is modeled by a Markov random process. The process defines a microlevel of the dynamic. A macrolevel is obtained by a scaling limit which leads to a system of integro-differential equations which determines a kind of mean field systems. Conditions when Gutenberg-Richter empirical law are presented on the mean field level. These conditions are rather universal and do not depend on features of resistant forces.

Pechersky, E; Sadowski, G; Yambartsev, A

2014-01-01

408

Ultrafast microchannel plate photomultipliers.  

PubMed

Performance characteristics of several new types of photomultiplier tubes (PMT) with microchannel plates (MCP) are presented in this paper. They are the MCP-PMT with 6-microm diam channels, MCP-PMT with an S-l photocathode, and MCP-PMT with multi (discrete) anode and gatable MCP-PMT. Important requirements of an optical detector for picosecond lasers, fluorescence measurements, and material analysis are low light detectability, ultrafast time response, and versatile operation including modulation. The basic configuration, characteristics, and practical results of these detectors are described. PMID:20531532

Kume, H; Koyama, K; Nakatsugawa, K; Suzuki, S; Fatlowitz, D

1988-03-15

409

Earthquakes and Plate Tectonics  

NSDL National Science Digital Library

This activity, from the Real World Learning Objects Resource Library, allows students to use first-hand data analysis to "determine if there is any pattern to earthquake events and speculate on the causes of earthquakes." Intended to be an introductory activity for a unit of study on earthquakes, this 60-minute activity is complete with learning goals, step-by-step classroom procedures, materials, assessment activities, and resources for further information. The "Content Materials" section contains directions for students and graphics to help students understand earthquakes and plate tectonics. This is an excellent resource for geology and earth science instructors that is ready to use for the classroom.

2007-10-04

410

Plated wire memory subsystem  

NASA Technical Reports Server (NTRS)

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

Carpenter, K. H.

1974-01-01

411

Shuttle plate braiding machine  

NASA Technical Reports Server (NTRS)

A method and apparatus for moving yarn in a selected pattern to form a braided article. The apparatus includes a segmented grid of stationary support elements and a plurality of shuttles configured to carry yarn. The shuttles are supported for movement on the grid assembly and each shuttle includes a retractable plunger for engaging a reciprocating shuttle plate that moves below the grid assembly. Such engagement at selected times causes the shuttles to move about the grid assembly in a selected pattern to form a braided article of a particular geometry.

Huey, Jr., Cecil O. (Inventor)

1994-01-01

412

Plates on the Move  

NSDL National Science Digital Library

In this activity, students create a model of sea floor spreading using two sheets of white paper and a metric ruler. The paper strips are pulled through a slit representing a mid-ocean ridge and divergent plate boundary. The model mimics how molten material rises to the surface and then spreads out in both directions. The resource is part of the teacher's guide accompanying the video, NASA SCI Files: The Case of the Shaky Quake. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.

413

40 CFR 426.45 - Standards of performance for new sources.  

Code of Federal Regulations, 2012 CFR

...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...

2012-07-01

414

40 CFR 426.45 - Standards of performance for new sources.  

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

415

40 CFR 426.45 - Standards of performance for new sources.  

Code of Federal Regulations, 2011 CFR

...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...

2011-07-01

416

40 CFR 426.45 - Standards of performance for new sources.  

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

417

Electrochemical Machining of Metal Plates  

SciTech Connect

Electrochemical machining (ECM) with concentrated sodium chlorate electrolyte was used to rapidly cut a circular groove (13 cm diameter, 0.2 cm wide) through a 0.15 cm thick sheet of steel--thus opening a 5-inch porthole in as little as 10 minutes. The most favorable operating conditions were: T = 22 C; chlorate concentration 600 g NaClO{sub 3}/liter-solution; electric power of 100 A at 10 V; and flow of 0.5 l/s at a pressure drop of 10 kPa (1.5 psi). The porthole may be removed entirely by electrochemical means, or the electrochemical dissolution may continue until only thin membrane remains that is subsequently cut with a utility knife. An array of thermocouples was used to track temperature in the flowing solution and in the trough being machined; the maximum increase in temperature in the trough was 5 C over that of the flowing electrolyte which increased in temperature by 19 C because of power dissipation. ECM is shown feasible for rapid perforation of plates of ferrous and non-ferrous metals using portable equipment and commercial batteries. The technique can be extended to cut perforations of arbitrary shape through non-planar surfaces using a deformable ring cathode. Analysis of the power requirements for electrolyte flow and ECM indicate a total system weight of less than 45 kg (100 lb) using a commercial NiMH battery. The technique is recommended for reduction to practice and demonstration on full scale as an engineering prototype.

Cooper, J F; Evans, M C

2005-03-04

418

Automatic number plate detection for Korean vehicles  

Microsoft Academic Search

We consider the task of detection of Korean vehicle number plates (also named license plates or registration plates in other countries). A system for number plate detection must cope with wide variations in the appearance of the plates. Few yeas ago, Korea government permits the new types of license plates with wide width as same as foreign country. It occurred

Ho-Sub Yoon; Hong-Chang Lee; Jae-Yeon Lee

2009-01-01

419

Plate tectonics on Venus  

NASA Technical Reports Server (NTRS)

The high surface temperature of Venus implies a permanently buoyant lithosphere and a thick basaltic crust. Terrestrial-style tectonics with deep subduction and crustal recycling is not possible. Overthickened basaltic crust partially melts instead of converting to eclogite. Because mantle magmas do not have convenient access to the surface the Ar-40 abundance in the atmosphere should be low. Venus may provide an analog to Archean tectonics on the earth.

Anderson, D. L.

1981-01-01

420

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

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Nominal wall thickness (t) for steel pipe. 192...STANDARDS Pipe Design 192.109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall thickness for steel pipe is not...

2011-10-01

421

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Nominal wall thickness (t) for steel pipe. 192...STANDARDS Pipe Design 192.109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall thickness for steel pipe is not...

2013-10-01

422

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Nominal wall thickness (t) for steel pipe. 192...STANDARDS Pipe Design 192.109 Nominal wall thickness (t ) for steel pipe. (a) If the nominal wall thickness for steel pipe is not...

2010-10-01

423

EGDT-1040 AutoCAD - Drawing Standards  

NSDL National Science Digital Library

Lines Letters Location - Many Items Contribute To Drawing Standards Core Standards: The following standard from the Technical Design 1 standards will be promoted on this page. Standard 2 Students will be able to understand and demonstrate the use of the alphabet of Lines. Objective 1 Understand and demonstrate the recommended thickness of lines.

Allred, Jonathan

2012-09-05

424

Hybrid damping of smart, functionally graded plates using piezoelectric, fiber-reinforced composites.  

PubMed

This paper deals with the investigation of active, constrained layer damping (ACLD) of smart, functionally graded (FG) plates. The constraining layer of the ACLD treatment is considered to be made of a piezoelectric, fiber-reinforced composite (PFRC) material with enhanced effective piezoelectric coefficient that quantifies the in-plane actuating force due to the electric field applied across the thickness of the layer. The Young's modulus and the mass density of the FG plates are assumed to vary exponentially along the thickness of the plate, and the Poisson's ratio is assumed to be constant over the domain of the plate. A finite-element model has been developed to model the open-loop and closed-loop dynamics of the FG plates integrated with two patches of ACLD treatment. The frequency response of the plates revealed that the active patches of ACLD treatment significantly improve the damping characteristics of the FG plates over the passive damping. Emphasis has been placed on investigating the effect of variation of piezoelectric fiber angle in the constraining layer of the ACLD treatment on the attenuating capability of the patches. The analysis also revealed that the activated patches of the ACLD treatment are more effective in controlling the vibrations of FG plates when the patches are attached to the surface of the FG plates with minimum stiffness than when they are attached to the surface of the same with maximum stiffness. PMID:17091850

Ray, Manas C

2006-11-01

425

Plating on difficult-to-plate metals: what's new  

SciTech Connect

Some of the changes since 1970 in procedures for plating on such materials as titanium, molybdenum, silicon, aluminum, and gallium arsenide are summarized. While basic procedures for plating some of these materials were developed as many as 30 to 40 years ago, changes in the end uses of the plated products have necessitated new plating processes. In some cases, vacuum techniques - such as ion bombardment, ion implantation, and vacuum metallization - have been introduced to improve the adhesion of electrodeposits. In other cases, these techniques have been used to deposit materials upon which electrodeposits are required.

Wiesner, H.J.

1980-07-30

426

Laser detection of material thickness  

DOEpatents

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

Early, James W. (Los Alamos, NM)

2002-01-01

427

Development of simple model for creep analysis of thick welded joints (1st report): Creep characteristics of thick welded joints and their improvement  

Microsoft Academic Search

To ensure the safety of high?temperature facilities, such as fast breeder reactors, throughout their service life, it is necessary to be able to predict their creep deformation with sufficient accuracy. The welds produced in the thick plates of these facilities have an extremely complex thermal history and therefore extremely in?homogeneous characteristics, including creep behaviour. This makes it difficult and laborious

K. Nakacho; Y. Ueda; J. Kinugawa; M. Yamazaki

1994-01-01

428

Bobbin-Tool Friction-Stir Welding of Thick-Walled Aluminum Alloy Pressure Vessels  

Microsoft Academic Search

It was desired to assemble thick-walled Al alloy 2219 pressure vessels by bobbin-tool friction-stir welding. To develop the welding-process, mechanical-property, and fitness-for-service information to support this effort, extensive friction-stir welding-parameter studies were conducted on 2.5 cm. and 3.8 cm. thick 2219 Al alloy plate. Starting conditions of the plate were the fully-heat-treated (-T62) and in the annealed (-O) conditions. The

E C Dalder; J W Pastrnak; J Engel; R S Forrest; E Kokko; K M Ternan; D Waldron

2007-01-01

429

Focusing and waveguiding of Lamb waves in micro-fabricated piezoelectric phononic plates.  

PubMed

This paper presents results on the numerical and experimental studies of focusing and waveguiding of the lowest anti-symmetric Lamb wave in micro-fabricated piezoelectric phononic plates. The phononic structure was based on an AT-cut quartz plate and consisted of a gradient-index phononic crystal (GRIN PC) lens and a linear phononic plate waveguide. The band structures of the square-latticed AT-cut quartz phononic crystal plates with different filling ratios were analyzed using the finite element method. The design of a GRIN PC plate lens which is attached with a linear phononic plate waveguide is proposed. In designing the waveguide, propagation modes in square-latticed PC plates with different waveguide widths were studied and the results were served for the experimental design. In the micro-fabrication, deep reactive ion etching (Deep-RIE) process with a laboratory-made etcher was utilized to fabricate both the GRIN PC plate lens and the linear phononic waveguide on an 80 ?m thick AT-cut quartz plate. Interdigital transducers were fabricated directly on the quartz plate to generate the lowest anti-symmetric Lamb waves. A vibro-meter was used to detect the wave fields and the measured results on the focusing and waveguiding of the piezoelectric GRIN PC lens and waveguide are in good accordance with the numerical predictions. The results of this study may serve as a basis for developing an active micro plate lens and related devices. PMID:24909597

Chiou, Meng-Jhen; Lin, Yu-Ching; Ono, Takahito; Esashi, Masayoshi; Yeh, Sih-Ling; Wu, Tsung-Tsong

2014-09-01

430

Nonlinear analysis of piezoelectric nanocomposite energy harvesting plates  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

431

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

NASA Astrophysics Data System (ADS)

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

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

2007-06-01

432

Constraining the Mean Crustal Thickness on Mercury  

NASA Technical Reports Server (NTRS)

The topography of Mercury is poorly known, with only limited radar and stereo coverage available. However, radar profiles reveal topographic contrasts of several kilometers over wavelengths of approximately 1000 km. The bulk of Mercury's geologic activity took place within the first 1 Ga of the planet's history), and it is therefore likely that these topographic features derive from this period. On Earth, long wavelength topographic features are supported either convectively, or through some combination of isostasy and flexure. Photographic images show no evidence for plume-like features, nor for plate tectonics; I therefore assume that neither convective support nor Pratt isostasy are operating. The composition and structure of the crust of Mercury are almost unknown. The reflectance spectrum of the surface of Mercury is similar to that of the lunar highlands, which are predominantly plagioclase. Anderson et al. used the observed center-of-mass center-of-figure offset together with an assumption of Airy isostasy to infer a crustal thickness of 100-300 km. Based on tidal despinning arguments, the early elastic thickness (T(sub e)) of the (unfractured) lithosphere was approximately equal to or less than 100 km. Thrust faults with lengths of up to 500 km and ages of about 4 Ga B.P. are known to exist on Mercury. Assuming a semicircular slip distribution and a typical thrust fault angle of 10 degrees, the likely vertical depth to the base of these faults is about 45 km. More sophisticated modelling gives similar or slightly smaller answers. The depth to the base of faulting and the elastic layer are usually similar on Earth, and both are thought to be thermally controlled. Assuming that the characteristic temperature is about 750 K, the observed fault depth implies that the heat flux at 4 Ga B.P. is unlikely to be less than 20 mW m(exp -2) for a linear temperature gradient. For an elastic thickness of 45 km, topography at 1000 km wavelength is likely to be about 60% compensated. There are thus likely to be considerable lateral variations in crustal thickness. Additional information is contained in the original extended abstract.

Nimmo, F.

2001-01-01

433

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

Microsoft Academic Search

We have used free-air gravity anomaly and bathymetric data, together with a moving window admittance technique, to determine the spatial variation in oceanic elastic thickness, Te, in the Western Pacific ocean. Synthetic tests using representative seamounts show that Te can be recovered to an accuracy of 5 km for plates up to 30 km thick, with increased accuracy of

L. M. Kalnins; A. B. Watts

2009-01-01

434

The science behind Plate Tectonics  

NSDL National Science Digital Library

Plate tectonics is a quantitative, robust and testable, geologic model describing the surface motions of Earth's outer skin. It is based on real data and assumptions, and built using the scientific method. New space geodesy data provide important quantitative (and independent) tests of this model. In general, these new data show a close match to model predictions, and suggest that plate motion is steady and uniform over millions of years. Active research continues to refine the model and to better our understanding of plate motion and tectonics. The exercise presented here aims to help students experience the process of doing science and to understand the science underlying the plate tectonic theory. Key words: plate tectonics, global plate motion models, assumptions, geologic data (spreading rates, transform fault azimuths, earthquake slip vectors), space geodesy tests.

Weber, John

435

Plate Tectonics: Lines of Evidence  

NSDL National Science Digital Library

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.

National Science Teachers Association (NSTA)

2006-11-01

436

Tectonics of the Easter plate  

NASA Technical Reports Server (NTRS)

A new model for the Easter plate is presented in which rift propagation has resulted in the formation of a rigid plate between the propagating and dying ridges. The distribution of earthquakes, eleven new focal mechanisms, and existing bathymetric and magnetic data are used to describe the tectonics of this area. Both the Easter-Nazca and Easter-Pacific Euler poles are sufficiently close to the Easter plate to cause rapid changes in rates and directions of motion along the boundaries. The east and west boundaries are propagating and dying ridges; the southwest boundary is a slow-spreading ridge and the northern boundary is a complex zone of convergent and transform motion. The Easter plate may reflect the tectonics of rift propagation on a large scale, where rigid plate tectonics requires boundary reorientation. Simple schematic models to illustrate the general features and processes which occur at plates resulting from large-scale rift propagation are used.

Engeln, J. F.; Stein, S.

1984-01-01

437

Tectonic Plate Movements and Hotspots  

NSDL National Science Digital Library

This lesson introduces the idea that rates and directions of plate movements can be measured. The discussion centers on the use of mantle 'hotspots' to determine plate motions. Examples include the Hawaiian Islands, the Galapagos Islands, and the Yellowstone hotspot. The lesson includes an activity in which students use online resources to answer questions about the Galapagos Islands and measure plate movement rates using online data for the Hawaiian Islands hotspot.

Rhinehart, Ken

438

Improved Coal-Thickness Measurement  

NASA Technical Reports Server (NTRS)

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

Barr, T. A.

1984-01-01

439

Active control of plates using compressional constrained layer damping  

NASA Astrophysics Data System (ADS)

Sound radiation from a plate into an acoustic cavity is actively controlled using patches of Active Compressional Constrained Layer Damping (ACCLD). The ACCLD, under consideration, consists of piezoelectric fibers embedded across the thickness of a visco-elastic matrix in order to control the compressional damping characteristics of the composite. The effectiveness of the ACCLD treatments in attenuating the sound radiation from thin plates into cavities is demonstrated theoretically and experimentally. A Finite Element Model (FEM) is developed to describe the dynamic interaction between the plate, the ACCLD patches and the acoustic cavity. The FEM is used to predict the dynamics of the plate/acoustic cavity and the sound pressure field for different control strategies. The predictions of the FEM are validated experimentally using a square aluminum plate whose sides are 29.8 cm and thickness of 0.04 cm. The plate is mounted on a 29.8 cm x 29.8 cm x 75 cm cavity. The test plate is treated with a single ACCLD patch placed at the plate center. The patch is 5 cm x 5 cm x 0.03125 cm which is made of 15-25% lead zirconate titanate (PZT) fibers embedded in soft and hard polymeric resin matrices and provided with silver-epoxy electrodes. Vibration and sound pressure level attenuations of about 70% are obtained, at the plate/cavity first mode of vibration, with a maximum control voltage of 330 volts using a derivative feedback controller. Such attenuations are attributed to the effectiveness of the ACCLD treatment in increasing the modal damping ratios by about a factor of four over those or conventional Passive Constrained Layer Damping (PCLD) treatments. Comparisons between the theoretical predictions of the FEM with the experimental results indicate close agreement between theory and experiments. The obtained results suggest the potential of the ACCLD treatments in controlling the sound radiation from plates into acoustic cavities. Such potential can be exploited in many critical applications such as cabins of aircrafts and automobiles to ensure quiet environments for the occupants.

Shields, Wilfred Henry

1997-12-01

440

Carbon-assisted flyer plates  

DOEpatents

A laser driven flyer plate utilizing an optical fiber connected to a laser. The end of the optical fiber has a layer of carbon and a metal layer deposited onto it. The carbon layer provides the laser induced plasma which is superior to the plasma produced from most metals. The carbon layer plasma is capable of providing a flatter flyer plate, converting more of the laser energy to driving plasma, promoting a higher flyer plate acceleration, and providing a more uniform pulse behind the plate. In another embodiment, the laser is in optical communication with a substrate onto which a layer of carbon and a layer of metal have been deposited.

Stahl, David B. (Los Alamos, NM); Paisley, Dennis L. (Santa Fe, NM)

1994-01-01

441

The Nature of Tectonic Plates  

NSDL National Science Digital Library

This lesson provides an overview of the various types of interactions between tectonic plates. The discussion uses the analogy of a cracked egg to describe the tectonic plates composing Earth's crust. Other topics include the concentrated earthquake and volcanic activity associated with plate boundaries, types of interactions at the boundaries, and how plate motions are affecting the Atlantic and Pacific Oceans. The lesson includes an activity in which students will use online references to locate a hypothetical nuclear power plant in a geologically safe area, investigate the history of large earthquakes in South Carolina, provide a likely location for a hypothetical geothermal power plant, and others.

Rhinehart, Ken

442

License Plates of the World  

NSDL National Science Digital Library

Whether you're interested in collecting license plates, or are just moving to Andorra and wonder what your car will be wearing when it gets there, this site provided by collector Michael Kustermann can be a handy reference. A winner in the "labor of love" website category, this frames-based directory contains pictures of and descriptive information about a dizzying range of automobile license plates, arranged geographically. Special issue and commemorative plates are also covered, as well as links to collector's clubs and a bibliography about the art and science of license plate hunting and gathering. You'll never look at bumpers quite the same way.

443

The Generation Mechanism of Material Property Distribution induced by Fiber Behavior for FRP Products during Injection Molding Detailed Analyses of Fiber Length Distribution in Thin Plates  

Microsoft Academic Search

Injection molded products used with fiber-reinforced plastics often exhibit deformation and cracking because of anisotropic property induced fiber orientation. In our previous study, using the thin-plate less than 1 mm thick, the fiber length distribution through the plate thickness and along the molding direction was investigated. In the present study, detailed analyses of the fiber length distribution, comparing 0.7 mm-thick

Hiroshi Furuhashi; Kosuke Noda; Kazuhito Satoh; Masahiro Seto; Masashi Yamabe

2010-01-01

444

Intermittent plate tectonics?  

PubMed

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

Silver, Paul G; Behn, Mark D

2008-01-01

445

Plate Tectonics: Earthquake Epicenter  

NSDL National Science Digital Library

This lesson provides an overview of destructive earthquakes and their connection to tectonic movements of the Earth's crust. It includes a discussion of some especially destructive historic earthquakes, and a brief introduction to contintental drift and the theory of plate tectonics. There is also discussion of basic seismology (types of waves) and measures of the magnitude of an earthquake (the Richter Scale). The lesson inlcudes an activity in which students use an online simulator to locate the epicenter of an earthquake using readings from three different seismograph stations. After they have completed the simulation, they attempt to locate the epicenter of a real earthquake using data from the United States Geological Survey (USGS) earthquake website.

Pratte, John

446

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

447

A model of convergent plate margins based on the recent tectonics of Shikoku, Japan  

NASA Technical Reports Server (NTRS)

A viscoelastic finite element plate tectonic model is applied to displacement data for the island of Shikoku, Japan. The flow properties and geometry of the upper portions of the earth are assumed known from geophysical evidence, and the loading characteristics are determined from the model. The nature of the forces acting on the Philippine Sea plate, particularly in the vicinity of the Nankai trough, is determined. Seismic displacement data related to the 1946 Nankaido earthquake are modeled in terms of a thick elastic plate overlying a fluidlike substratum. The sequence of preseismic and seismic displacements can be explained in terms of two independent processes operating on elastic lithospheric plates: a strain accumulation process caused by vertical downward forces acting on or within the lithosphere in the vicinity of the trench, and a strain release process caused by plate failure along a preexisting zone on weakness. This is a restatement of Reid's elastic rebound theory in terms of elastic lithospheric plates.

Bischke, R. E.

1974-01-01

448

Modeling RERTR experimental fuel plates using the plate code  

Microsoft Academic Search

Modeling results using the PLATE dispersion fuel performance code are presented for the U-Mo\\/Al experimental fuel plates from the RERTR-1, ?2, -3 and -5 irradiation tests. Agreement of the calculations with experimental data obtained in postirradiation examinations of these fuels, where available, is shown to be good. Use of the code to perform a series of parametric evaluations highlights the

S. L. Hayes; M. K. Meyer; G. L. Hofman; J. L. Snelgrove

2007-01-01

449

Geodynamical Analysis of Plate Reconstructions based on Subduction History Models  

NASA Astrophysics Data System (ADS)

We present a novel method to produce global subduction history models from plate reconstructions and use their predicted geodynamic behaviour as a quality metric for the physical consistency of absolute motions. We show that modelled slabs constructed by advecting material into the mantle according to absolute and relative plate motions given by a particular reconstruction are better correlated with the present day slab dips observed in mantle tomography than instantaneous kinematic quantities like present convergence rate. A complete simulation incorporating lithospheric thickness derived from oceanic age and a rheological model of the lithosphere was run using the Boundary Element Method-based software BEMEarth to infer the global pattern of mantle flow. The predicted plate motion orientations in the form of Euler pole location for the present day and mid-Cretaceous (125 Ma) were compared with the kinematic model for a set of rheologies and mantle structures, and found to be a robust and efficient indicator of the physical consistency of kinematic reconstructions based on their effect on the balance of plate driving forces. As an application example, during the Early Cretaceous, the predicted motion of the Farallon plate was found to be more consistent with the regional geology of the Western North American Cordillera system than the instantaneous motion suggested by a reconstruction at 125 Ma based on sparse hotspot track data on the Pacific Plate. This suggests that a methodology based on forward geodynamic modellling could be used to predict absolute plate motions in reconstructions for times that are ill-constrained by observations constraining absolute plate motions.

Quevedo, L. E.; Butterworth, N. P.; Matthews, K. J.; Morra, G.; Mller, R. D.

2011-12-01

450

Thickness of 90 ferroelectric domain walls in (Ba,Pb)TiO3 single crystals  

Microsoft Academic Search

90 ferroelectric domain boundaries were observed by direct transmission electron microscopy in single crystals of pure BaTiO3 and (Ba,Pb)TiO3 solid solutions. Domain-wall thickness measurements were made from electron image plates by a densitometer-trace-curve-fitting technique. Boundary widths varied from 50 to 150 . These results are compared with theoretical estimates of 90 domain-wall thicknesses and correlated with the relative purity levels

M. D. Dennis; R. C. Bradt

1974-01-01

451

Tin oxide coating of aluminous porcelain by reactive ion plating.  

PubMed

Alumina reinforced dental porcelain has been coated directly with tin oxide by reactive ion plating. Samples were prepared at different distances from the tin source in the ion plating rig. Tensile bond strengths of treated and untreated porcelain discs to a commercially available phosphate-methacrylate based dental cement were determined. Bond strengths of certain coated samples were found to be in excess of the cohesive strength of the porcelain substrates (greater than 7.8 MPa), whereas untreated porcelain achieved an average bond strength of only 3.4 MPa. The microstructures of coatings produced under conditions similar to those which yielded the maximum bond strength were examined in a scanning electron microscope and were found to be approximately 0.5 microns thick. It is believed that ion plating has great potential for rendering inert ceramic surfaces capable of direct bonding to dental cements. PMID:1939818

McCrory, P V; Tinston, S; Piddock, V; Kelly, P; Combe, E C; Arnell, R D

1991-06-01

452

Rapid Weakening of Subducting Plates From Trench-Parallel Estimates of Flexural Rigidity  

NASA Astrophysics Data System (ADS)

The percentage of slab pull force transmitted from the slab to the subducting plate depends on the slab strength (e.g., Conrad and Hager, 2001). Slab strength has been studied in the context of plate bending within subduction zones for a wide range of rheologies (i.e., perfectly elastic, perfectly viscous, perfectly plastic, layered brittle-ductile layered), but applicability of these rheologic models cannot be distinguished based on trench-perpendicular plate bending models alone (Forsyth, 1980). Consequently, a method was developed to directly measure variations in plate strength with distance from the trench and has found significant plate weakening within 100 km of the Kermadec trench (Billen and Gurnis, 2005). Using the same method we show that rapid plate weakening trenchward of the forebulge also exists at the Tonga and Japan-Izu-Bonin subduction zones within 100 km of the trench. The observed plate weakening provides further evidence for a plate rheology that leads to significant lithospheric-scale yielding (loss of elastic strength and reduction in effective viscosity) within the bending region of the subducting plate. This rapid weakening within the shallow, low curvature, region of the plate may significantly decrease energy dissipation related to plate bending compared to past calculations that assume constant strength, plate thickness and plate curvature. While a decrease in bending energy dissipation would provide more energy for slab pull, lithospheric plate weakening may decrease transmission to the subducting plate. Additionally, the high degree of lithospheric weakening suggests that plate age has a weaker influence on slab strength and energy dissipation then previously believed, as very old oceanic lithosphere weakens to effective elastic thickness predicted for relatively young plates. Billen, M. I., Gurnis, H.A., 2005. Constraints on subducting plate strength within the Kermadec trench. J. Geophys. Res. 110, B05407, doi:10.1029/2004JB003308. Conrad, C.P., Hager, B.H., 2001. Mantle convection with strong subduction zones. Geophys. J. Int. 144 (2), 271-288. Forsyth, D.W., 1980. Comparison of mechanical models of oceanic lithosphere. J. Geophys. Res. 85, 6364-6368.

Arredondo, K.; Billen, M. I.

2011-12-01

453

Spall behavior of rolled aluminum 5083-H116 plate  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

454

Optimization of electromagnetic absorption in laminated composite plates  

Microsoft Academic Search

Analyzes an electromagnetic model of radar-absorbing layered structures for several stacking sequences of a woven glass\\/vinyl ester laminate, foam layers, and resistive sheets. It considers configurations that are either deposited on different backing materials or embedded in a laminated sandwich plate. Through-the-thickness layer dimensions and sheet resistances offering the best signal absorption over a specified frequency range are found for

Karel Matous; George J. Dvorak

2003-01-01

455

Carbon\\/Carbon Composite Bipolar Plate for PEM Fuel Cells  

Microsoft Academic Search

Carbon\\/carbon-composite bipolar plates for proton- exchange-membrane fuel cells have been fabricated by slurry molding a chopped -fiber preform followed by sealing with chemically vapor-infiltrated ca