Planetary benchmarks. [structural design criteria for radar reference devices on planetary surfaces

NASA Technical Reports Server (NTRS)

Uphoff, C.; Staehle, R.; Kobrick, M.; Jurgens, R.; Price, H.; Slade, M.; Sonnabend, D.

1978-01-01

Design criteria and technology requirements for a system of radar reference devices to be fixed to the surfaces of the inner planets are discussed. Offshoot applications include the use of radar corner reflectors as landing beacons on the planetary surfaces and some deep space applications that may yield a greatly enhanced knowledge of the gravitational and electromagnetic structure of the solar system. Passive retroreflectors with dimensions of about 4 meters and weighing about 10 kg are feasible for use with orbiting radar at Venus and Mars. Earth-based observation of passive reflectors, however, would require very large and complex structures to be delivered to the surfaces. For Earth-based measurements, surface transponders offer a distinct advantage in accuracy over passive reflectors. A conceptual design for a high temperature transponder is presented. The design appears feasible for the Venus surface using existing electronics and power components.

Experimental studies of hypersonic shock-wave boundary-layer interactions

NASA Technical Reports Server (NTRS)

Lu, Frank K.

1992-01-01

Two classes of shock-wave boundary-layer interactions were studied experimentally in a shock tunnel in which a low Reynolds number, turbulent flow at Mach 8 was developed on a cold, flat test surface. The two classes of interactions were: (1) a swept interaction generated by a wedge ('fin') mounted perpendicularly on the flat plate; and (2) a two-dimensional, unseparated interaction induced by a shock impinging near an expansion corner. The swept interaction, with wedge angles of 5-20 degrees, was separated and there was also indication that the strongest interactions prossessed secondary separation zones. The interaction spread out extensively from the inviscid shock location although no indication of quasi-conical symmetry was evident. The surface pressure from the upstream influence to the inviscid shock was relatively low compared to the inviscid downstream value but it rose rapidly past the inviscid shock location. However, the surface pressure did not reach the downstream inviscid value and reasons were proposed for this anomalous behavior compared to strongly separated, supersonic interactions. The second class of interactions involved weak shocks impinging near small expansion corners. As a prelude to studying this interaction, a hypersonic similarity parameter was identified for the pure, expansion corner flow. The expansion corner severely damped out surface pressure fluctuations. When a shock impinged upstream of the corner, no significant changes to the surface pressure were found as compared to the case when the shock impinged on a flat plate. But, when the shock impinged downstream of the corner, a close coupling existed between the two wave systems, unlike the supersonic case. This close coupling modified the upstream influence. Regardless of whether the shock impinged ahead or behind the corner, the downstream region was affected by the close coupling between the shock and the expansion. Not only was the mean pressure distribution modified but the unsteadiness in the surface pressure was reduced compared to the flat-plate case.

The wavefront compensation of free space optics utilizing micro corner-cube-reflector arrays

NASA Astrophysics Data System (ADS)

You, Shengzui; Yang, Guowei; Li, Changying; Bi, Meihua; Fan, Bing

2018-01-01

The wavefront compensation effect of micro corner-cube-reflector arrays (MCCRAs) in modulating retroreflector (MRR) free-space optical (FSO) link is investigated theoretically and experimentally. Triangular aperture of MCCRAs has been optically characterized and studied in an indoor atmospheric turbulence channel. The use of the MCCRAs instead of a single corner-cube reflector (CCR) as the reflective device is found to improve dramatically the quality of the reflected beam spot. We draw a conclusion that the MCCRAs can in principle yield a powerful wavefront compensation in MRR FSO communication links.

A finite element formulation for supersonic flows around complex configurations

NASA Technical Reports Server (NTRS)

Morino, L.

1974-01-01

The problem of small perturbation potential supersonic flow around complex configurations is considered. This problem requires the solution of an integral equation relating the values of the potential on the surface of the body to the values of the normal derivative, which is known from the small perturbation boundary conditions. The surface of the body is divided into small (hyperboloidal quadrilateral) surface elements which are described in terms of the Cartesian components of the four corner points. The values of the potential (and its normal derivative) within each element are assumed to be constant and equal to its value at the centroid of the element. This yields a set of linear algebraic equations whose coefficients are given by source and doublet integrals over the surface elements. Closed form evaluations of the integrals are presented.

Sum rules for the uniform-background model of an atomic-sharp metal corner

NASA Astrophysics Data System (ADS)

Streitenberger, P.

1994-04-01

Analytical results are derived for the electrostatic potential of an atomic-sharp 90° metal corner in the uniform-background model. The electrostatic potential at a free jellium edge and the jellium corner, respectively, is determined exactly in terms of the energy per electron of the uniform electron gas integrated over the background density. The surface energy, the edge formation energy and the derivative of the corner formation energy with respect to the background density are given as integrals over the electrostatic potential. The present approach represents a novel approach to such sum rules, inclusive of the Budd-Vannimenus sum rules for a free jellium surface, based on general properties of linear response functions.

Helium as a tracer for fluids released from Juan de Fuca lithosphere beneath the Cascadia forearc

USGS Publications Warehouse

McCrory, Patricia A.; Constantz, James E.; Hunt, Andrew G.; Blair, James Luke

2016-01-01

The ratio between helium isotopes (3He/4He) provides an excellent geochemical tracer for investigating the sources of fluids sampled at the Earth's surface. 3He/4He values observed in 25 mineral springs and wells above the Cascadia forearc document a significant component of mantle-derived helium above Juan de Fuca lithosphere, as well as variability in 3He enrichment across the forearc. Sample sites arcward of the forearc mantle corner (FMC) generally yield significantly higher ratios (1.2-4.0 RA) than those seaward of the corner (0.03-0.7 RA). The highest ratios in the Cascadia forearc coincide with slab depths (40-45 km) where metamorphic dehydration of young oceanic lithosphere is expected to release significant fluid and where tectonic tremor occurs, whereas little fluid is expected to be released from the slab depths (25-30 km) beneath sites seaward of the corner.Tremor (considered a marker for high fluid pressure) and high RA values in the forearc are spatially correlated. The Cascadia tremor band is centered on its FMC, and we tentatively postulate that hydrated forearc mantle beneath Cascadia deflects a significant portion of slab-derived fluids updip along the subduction interface, to vent in the vicinity of its corner. Furthermore, high RA values within the tremor band just arcward of the FMC, suggest that the innermost mantle wedge is relatively permeable.Conceptual models require: (1) a deep fluid source as a medium to transport primordial 3He; (2) conduits through the lithosphere which serve to speed fluid ascent to the surface before significant dilution from radiogenic 4He can occur; and (3) near lithostatic fluid pressure to keep conduits open. Our spatial correlation between high RA values and tectonic tremor provides independent evidence that tremor is associated with deep fluids, and it further suggests that high pore pressures associated with tremor may serve to keep fractures open for 3He migration through ductile upper mantle and lower crust.

Surface-Wave Pulse Routing around Sharp Right Angles

NASA Astrophysics Data System (ADS)

Gao, Z.; Xu, H.; Gao, F.; Zhang, Y.; Luo, Y.; Zhang, B.

2018-04-01

Surface-plasmon polaritons (SPPs), or localized electromagnetic surface waves propagating on a metal-dielectric interface, are deemed promising information carriers for future subwavelength terahertz and optical photonic circuitry. However, surface waves fundamentally suffer from scattering loss when encountering sharp corners in routing and interconnection of photonic signals. Previous approaches enabling scattering-free surface-wave guidance around sharp corners are limited to either volumetric waveguide environments or extremely narrow bandwidth, being unable to guide a surface-wave pulse (SPP wave packet) on an on-chip platform. Here, in a surface-wave band-gap crystal implemented on a single metal surface, we demonstrate in time-domain routing a surface-wave pulse around multiple sharp right angles without perceptible scattering. Our work not only offers a solution to on-chip surface-wave pulse routing along an arbitrary path, but it also provides spatiotemporal information on the interplay between surface-wave pulses and sharp corners, both of which are desirable in developing high-performance large-scale integrated photonic circuits.

Experimental investigation of the braking and cornering characteristics of 30 x 11.5-14.5, type 8, aircraft tires with different tread patterns

NASA Technical Reports Server (NTRS)

Dreher, R. C.; Tanner, J. A.

1974-01-01

An investigation was conducted at the aircraft landing loads and traction facility to study the braking and cornering characteristics, including the drag-force and cornering-force friction coefficients, of 30 by 11.5-14.5, type VIII aircraft tires with five different tread patterns. Test data were obtained on dry, damp, and flooded runway surfaces over a range of yaw angles from 0 deg to 12 deg at ground speeds from 5 knots to 100 knots. The results of this investigation indicate that a tread pattern consisting of transverse cuts across the entire width of the tread slightly improved the tire traction performance on wet surfaces. The braking and cornering capability of the tires was degraded by thin-film lubrication and tire hydroplaning effects on the wet runway surfaces. The braking capability of the tires decreased when the yaw angle was increased.

Cornering characteristics of a 40 by 14-16 type 7 aircraft tire and a comparison with characteristics of a C40 by 14-21 cantilever aircraft tire

NASA Technical Reports Server (NTRS)

Tanner, J. A.; Dreher, R. C.

1973-01-01

An investigation was conducted at the Langley aircraft landing loads and traction facility to determine the cornering characteristics of a 40 x 14-16 type VII aircraft tire. These characteristics, which include the cornering-force and drag-force friction coefficients and self-alining torque, were obtained for the tire operating on dry, damp and flooded runway surfaces over a range of yaw angles from 0 deg to 20 deg and at ground speeds from 5 to 100 knots, both with and without braking. The results of this investigation indicated that the cornering capability of the 40 x 14-16 type VII aircraft tire is degraded by high ground speeds, thin-film lubrication and tire hydroplaning effects on the wet surfaces, and brake torque. The cornering capability is greatly diminished when locked-wheel skids are encountered.

3-D Topo Surface Visualization of Acid-Base Species Distributions: Corner Buttes, Corner Pits, Curving Ridge Crests, and Dilution Plains

ERIC Educational Resources Information Center

Smith, Garon C.; Hossain, Md Mainul

2017-01-01

Species TOPOS is a free software package for generating three-dimensional (3-D) topographic surfaces ("topos") for acid-base equilibrium studies. This upgrade adds 3-D species distribution topos to earlier surfaces that showed pH and buffer capacity behavior during titration and dilution procedures. It constructs topos by plotting…

A finite-element analysis for steady and oscillatory supersonic flows around complex configurations

NASA Technical Reports Server (NTRS)

Morino, L.; Chen, L. T.

1974-01-01

The problem of small perturbation potential supersonic flow around complex configurations is considered. This problem requires the solution of an integral equation relating the values of the potential on the surface of the body to the values of the normal derivative, which is known from the small perturbation boundary conditions. The surface of the body is divided into small (hyperboloidal quadrilateral) surface elements, sigma sub i, which are described in terms of the Cartesian components of the four corner points. The values of the potential (and its normal derivative) within each element is assumed to be constant and equal to its value at the centroid of the element, and this yields a set of linear algebraic equations. The coefficients of the equation are given by source and doublet integrals over the surface elements, sigma sub i. The results obtained using the above formulation are compared with existing analytical and experimental results.

Experimental investigation of the cornering of a C40 x 14-21 cantilever aircraft tire

NASA Technical Reports Server (NTRS)

Dreher, R. C.; Tanner, J. A.

1973-01-01

An experimental investigation was conducted at the Langley aircraft landing loads and traction facility to define the cornering characteristics of a size C40 x14-21 aircraft tire of cantilever design. These characteristics, which include the cornering-force and drag-force friction coefficients and self-alining torque, were obtained for the tire operating on dry, damp, and flooded runway surfaces over a range of yaw angles from 0 deg to 20 deg and at ground speeds of 5 to 100 knots, both with and without braking. The results of this investigation show that the cornering-force and drag-force friction coefficients and self-alining torque were influenced by the yaw angle, ground speed, brake torque, surface wetness, and the locked-wheel condition.

Stress intensity factors for surface and corner cracks emanating from a wedge-loaded hole

NASA Technical Reports Server (NTRS)

Zhao, W.; Sutton, M. A.; Shivakumar, K. N.; Newman, J. C., Jr.

1994-01-01

To assist analysis of riveted lap joints, stress intensity factors are determined for surface and corner cracks emanating from a wedge-loaded hole by using a 3-D weight function method in conjunction with a 3-D finite element method. A stress intensity factor equation for surface cracks is also developed to provide a closed-form solution. The equation covers commonly-encountered geometrical ranges and retains high accuracy over the entire range.

Damage prediction of 7025 aluminum alloy during equal-channel angular pressing

NASA Astrophysics Data System (ADS)

Ebrahimi, M.; Attarilar, Sh.; Gode, C.; Djavanroodi, F.

2014-10-01

Equal-channel angular pressing (ECAP) is a prominent technique that imposes severe plastic deformation into materials to enhance their mechanical properties. In this research, experimental and numerical approaches were utilized to investigate the mechanical properties, strain behavior, and damage prediction of ECAPed 7025 aluminum alloy in various conditions, such as die channel angle, outer corner angle, and friction coefficient. Experimental results indicate that, after the first pass, the yield strength, ultimate tensile strength, and hardness magnitude are improved by approximately 95%, 28%, and 48.5%, respectively, compared with the annealed state, mainly due to grain refinement during the deformation. Finite element analysis shows that the influence of die channel angle is more important than that of outer corner angle or friction coefficient on both the strain behavior and the damage prediction. Also, surface cracks are the main cause of damage during the ECAP process for every die channel angle except for 90°; however, the cracks initiated from the neighborhood of the central regions are the possible cause of damage in the ECAPed sample with the die channel angle of 90°.

Growth Angle: A Microscopic View

NASA Technical Reports Server (NTRS)

Mazuruk, Konstantin; Croll, Arne; Volz, Martin P.

2017-01-01

A microscopic continuum mechanical model of the growth angle is proposed. It is based on the van der Waals type framework that is used for surface force phenomena. The obtained augmented Laplace type integro-differential equations are, in general, difficult to analyze. Here we focused primarily on the particular case of equal melt and crystal surface energies. We derived an approximate equation for the meniscus shape, and obtained an analytical relationship between the contact and the growth angle. Interestingly, the same result can be obtained using the macroscopic model of Herring. The case of a macroscopically sharp corner is also considered. For this case, the macroscopic angle is not defined and it can be any angle between the contact angles of both flat surfaces. The microscopic model yields the smooth shape for the meniscus that also is not unique, but depends on the initial position of the meniscus.

Full-Scale Evaluation of DuraDeck (registered trademark) and MegaDeck (trademark) Matting Systems

DTIC Science & Technology

2013-07-01

plates studded with threaded bolts were placed ERDC/GSL TR-13-27 10 underneath two pre-drilled corners of the panel. The plates were positioned so...metal plates studded with threaded ERDC/GSL TR-13-27 4 Figure 1. DuraDeck® mat panel, top surface. Figure 2. DuraDeck® mat panel, bottom surface...ERDC/GSL TR-13-27 5 bolts , as shown in Figure 3, underneath the mat corners and then installing special connector nuts from the top surface

Supported PV module assembly

DOEpatents

Mascolo, Gianluigi; Taggart, David F.; Botkin, Jonathan D.; Edgett, Christopher S.

2013-10-15

A supported PV assembly may include a PV module comprising a PV panel and PV module supports including module supports having a support surface supporting the module, a module registration member engaging the PV module to properly position the PV module on the module support, and a mounting element. In some embodiments the PV module registration members engage only the external surfaces of the PV modules at the corners. In some embodiments the assembly includes a wind deflector with ballast secured to a least one of the PV module supports and the wind deflector. An array of the assemblies can be secured to one another at their corners to prevent horizontal separation of the adjacent corners while permitting the PV modules to flex relative to one another so to permit the array of PV modules to follow a contour of the support surface.

Investigation of corner shock boundary layer interactions to understand inlet unstart

NASA Astrophysics Data System (ADS)

Funderburk, Morgan

2015-11-01

Inlet unstart is a detrimental phenomenon in dual-mode ramjet/scramjet engines that causes severe loss of thrust, large transient structural load, and potentially a loss of the aircraft. In order to analyze the effects that the corner shock boundary layer interaction (SBLI) has on initiating and perpetuating inlet unstart, a qualitative and quantitative investigation into mean and dynamic features of corner SBLI at various Mach numbers is made. Surface streakline visualization showed that the corner SBLI is highly three-dimensional with a dominant presence of corner separation vortex. Further, the peak r.m.s. pressure was located at the periphery of corner separation vortex, suggesting that the unsteady loading is caused by the corner vortex. Power spectral densities of wall-pressure fluctuations in the peak r.m.s. location were analyzed in order to characterize the dominant frequencies of oscillation of the flow structures and to unravel the dynamic interactions between them in order to expand the operating margin of future hypersonic air breathing vehicles.

Wear, friction, and temperature characteristics of an aircraft tire undergoing braking and cornering

NASA Technical Reports Server (NTRS)

Mccarty, J. L.; Yager, T. J.; Riccitiello, S. R.

1979-01-01

An investigation to evaluate the wear, friction, and temperature characteristics of aircraft tire treads fabricated from different elastomers is presented. The braking and cornering tests performed on aircraft tires retreaded with currently employed and experimental elastomers are described. The tread wear rate is discussed in relation to the slip ratio during braking and yaw angle during cornering. The extent of wear in either operational mode is examined in relation to the runway surface.

Spontaneous rise in open rectangular channels under gravity.

PubMed

Thammanna Gurumurthy, Vignesh; Roisman, Ilia V; Tropea, Cameron; Garoff, Stephen

2018-05-17

Fluid movement in microfluidic devices, porous media, and textured surfaces involves coupled flows over the faces and corners of the media. Spontaneous wetting of simple grooved surfaces provides a model system to probe these flows. This numerical study investigates the spontaneous rise of a liquid in an array of open rectangular channels under gravity, using the Volume-of-Fluid method with adaptive mesh refinement. The rise is characterized by the meniscus height at the channel center, outer face and the interior and exterior corners. At lower contact angles and higher channel aspect ratios, the statics and dynamics of the rise in the channel center show little deviation with the classical model for capillarity, which ignores the existence of corners. For contact angles smaller than 45°, rivulets are formed in the interior corners and a cusp at the exterior corner. The rivulets at long times obey the one-third power law in time, with a weak dependence on the geometry. The cusp behaviour at the exterior corner transforms into a smooth meniscus when the capillary force is higher in the channel, even for contact angles smaller than 45°. The width of the outer face does not influence the capillary rise inside the channel, and the channel size does not influence the rise on the outer face. Copyright © 2018 Elsevier Inc. All rights reserved.

Traction Characteristics of a 30 by 11.5-14.5, Type 8, Aircraft Tire on Dry, Wet and Flooded Surfaces

NASA Technical Reports Server (NTRS)

Yager, T. J.; Dreher, R. C.

1976-01-01

A limited test program was conducted to extend and supplement the braking and cornering data on a 30 x 11.5-14.5, type VIII, aircraft tire to refine the tire/runway friction model for use in the development of an aircraft ground performance simulation. Tire traction data were obtained on dry, wet and flooded runway surfaces at ground speeds ranging from 5 to 100 knots and at yaw angles extending up to 12 deg. These friction coefficients are presented as a function of slip characteristics, namely, the maximum and skidding drag coefficients and the maximum cornering coefficients are presented as a function of both ground speed and yaw angle to extend existing data on that tire size. Tire braking and cornering capabilities were shown to be affected by vehicle ground speed, wheel yaw attitude and the extent of surface wetness.

Hypothetical Reentry Thermostructural Performance of Space Shuttle Orbiter With Missing or Eroded Thermal Protection Tiles

NASA Technical Reports Server (NTRS)

Ko, William L.; Gong, Leslie; Quinn, Robert D.

2004-01-01

This report deals with hypothetical reentry thermostructural performance of the Space Shuttle orbiter with missing or eroded thermal protection system (TPS) tiles. The original STS-5 heating (normal transition at 1100 sec) and the modified STS-5 heating (premature transition at 800 sec) were used as reentry heat inputs. The TPS missing or eroded site is assumed to be located at the center or corner (spar-rib juncture) of the lower surface of wing midspan bay 3. For cases of missing TPS tiles, under the original STS-5 heating, the orbiter can afford to lose only one TPS tile at the center or two TPS tiles at the corner (spar-rib juncture) of the lower surface of wing midspan bay 3. Under modified STS-5 heating, the orbiter cannot afford to lose even one TPS tile at the center or at the corner of the lower surface of wing midspan bay 3. For cases of eroded TPS tiles, the aluminum skin temperature rises relatively slowly with the decreasing thickness of the eroded central or corner TPS tile until most of the TPS tile is eroded away, and then increases exponentially toward the missing tile case.

Detection of honeycomb cell walls from measurement data based on Harris corner detection algorithm

NASA Astrophysics Data System (ADS)

Qin, Yan; Dong, Zhigang; Kang, Renke; Yang, Jie; Ayinde, Babajide O.

2018-06-01

A honeycomb core is a discontinuous material with a thin-wall structure—a characteristic that makes accurate surface measurement difficult. This paper presents a cell wall detection method based on the Harris corner detection algorithm using laser measurement data. The vertexes of honeycomb cores are recognized with two different methods: one method is the reduction of data density, and the other is the optimization of the threshold of the Harris corner detection algorithm. Each cell wall is then identified in accordance with the neighboring relationships of its vertexes. Experiments were carried out for different types and surface shapes of honeycomb cores, where the proposed method was proved effective in dealing with noise due to burrs and/or deformation of cell walls.

Finite element model study of the effect of corner rounding on detectability of corner cracks using bolt hole eddy current

NASA Astrophysics Data System (ADS)

Underhill, P. R.; Krause, T. W.

2017-02-01

Recent work has shown that the detectability of corner cracks in bolt-holes is compromised when rounding of corners arises, as might occur during bolt-hole removal. Probability of Detection (POD) studies normally require a large number of samples of both fatigue cracks and electric discharge machined notches. In the particular instance of rounding of bolt-hole corners the generation of such a large set of samples representing the full spectrum of potential rounding would be prohibitive. In this paper, the application of Finite Element Method (FEM) modeling is used to supplement the study of detection of cracks forming at the rounded corners of bolt-holes. FEM models show that rounding of the corner of the bolt-hole reduces the size of the response to a corner crack to a greater extent than can be accounted for by loss of crack area. This reduced sensitivity can be ascribed to a lower concentration of eddy currents at the rounded corner surface and greater lift-off of pick-up coils relative to that of a straight-edge corner. A rounding with a radius of 0.4 mm (.016 inch) showed a 20% reduction in the strength of the crack signal. Assuming linearity of the crack signal with crack size, this would suggest an increase in the minimum detectable size by 25%.

Nb-Based Nb-Al-Fe Alloys: Solidification Behavior and High-Temperature Phase Equilibria

NASA Astrophysics Data System (ADS)

Stein, Frank; Philips, Noah

2018-03-01

High-melting Nb-based alloys hold significant promise for the development of novel high-temperature materials for structural applications. In order to understand the effect of alloying elements Al and Fe, the Nb-rich part of the ternary Nb-Al-Fe system was investigated. A series of Nb-rich ternary alloys were synthesized from high-purity Nb, Al, and Fe metals by arc melting. Solidification paths were identified and the liquidus surface of the Nb corner of the ternary system was established by analysis of the as-melted microstructures and thermal analysis. Complementary analysis of heat-treated samples yielded isothermal sections at 1723 K and 1873 K (1450 °C and 1600 °C).

Dual surface interferometer

DOEpatents

Pardue, R.M.; Williams, R.R.

1980-09-12

A double-pass interferometer is provided which allows direct measurement of relative displacement between opposed surfaces. A conventional plane mirror interferometer may be modified by replacing the beam-measuring path cube-corner reflector with an additional quarterwave plate. The beam path is altered to extend to an opposed plane mirrored surface and the reflected beam is placed in interference with a retained reference beam split from dual-beam source and retroreflected by a reference cube-corner reflector mounted stationary with the interferometer housing. This permits direct measurement of opposed mirror surfaces by laser interferometry while doubling the resolution as with a conventional double-pass plane mirror laser interferometer system.

Dual surface interferometer

DOEpatents

Pardue, Robert M.; Williams, Richard R.

1982-01-01

A double-pass interferometer is provided which allows direct measurement of relative displacement between opposed surfaces. A conventional plane mirror interferometer may be modified by replacing the beam-measuring path cube-corner reflector with an additional quarter-wave plate. The beam path is altered to extend to an opposed plane mirrored surface and the reflected beam is placed in interference with a retained reference beam split from dual-beam source and retroreflected by a reference cube-corner reflector mounted stationary with the interferometer housing. This permits direct measurement of opposed mirror surfaces by laser interferometry while doubling the resolution as with a conventional double-pass plane mirror laser interferometer system.

Nanoscale Phase Stability Reversal During the Nucleation and Growth of Titanium Oxide Minerals

NASA Astrophysics Data System (ADS)

Hummmer, D. R.; Heaney, P. J.; Kubicki, J. D.; Kent, P. R.; Post, J. E.

2008-12-01

Fine-grained titanium oxide minerals are important in soils, where they affect a variety of geochemical processes. They are also industrially important as catalysts, pigments, food additives, and dielectrics. Recent research has indicated an apparent reversal of thermodynamic stability between TiO2 phases at the nanoscale thought to be caused by an increased contribution of surface energy to the total free energy. Time-resolved X-ray diffraction (XRD) experiments in which titanium oxides crystallize from aqueous TiCl4 solutions confirm that anatase, a metastable phase, is always the first phase to nucleate under our range of initial conditions. Rutile peaks are observed only minutes after the first appearance of anatase, after which anatase abundance slowly decreases while rutile continues to form. Whole pattern refinement of diffraction data reveals that lattice constants of both phases increase throughout the crystallization process. In addition, transmission electron microscope (TEM) observations and kinetic modeling indicate that anatase does not undergo a solid-state transformation to the rutile structure as once thought. Instead, anatase appears to re-dissolve and then feed the growth of already nucleated rutile nanocrystals. Density functional theory (DFT) calculations were employed to model 1, 2, and 3 nm particles of both mineral phases. The total surface energies calculated from these models did yield lower values for anatase than for rutile by 8-13 kJ/mol depending on particle size, indicating that surface free energy is sufficient to account for stability reversal. However, these whole-particle surface energies were much higher than the sum of energies of each particle's constituent crystallographic surfaces. We attribute the excess energy to defects associated with the edges and corners of nanoparticles, which are not present on a 2-D periodic surface. This previously unreported edge and corner energy may play a dominant role in the stability reversal of nanocrystalline titanium oxides, as well as other mineral systems susceptible to reversals in phase stability at the nanoscale.

Enhancement of plasma generation in catalyst pores with different shapes

NASA Astrophysics Data System (ADS)

Zhang, Yu-Ru; Neyts, Erik C.; Bogaerts, Annemie

2018-05-01

Plasma generation inside catalyst pores is of utmost importance for plasma catalysis, as the existence of plasma species inside the pores affects the active surface area of the catalyst available to the plasma species for catalytic reactions. In this paper, the electric field enhancement, and thus the plasma production inside catalyst pores with different pore shapes is studied with a two-dimensional fluid model. The results indicate that the electric field will be significantly enhanced near tip-like structures. In a conical pore with small opening, the strongest electric field appears at the opening and bottom corners of the pore, giving rise to a prominent ionization rate throughout the pore. For a cylindrical pore, the electric field is only enhanced at the bottom corners of the pore, with lower absolute value, and thus the ionization rate inside the pore is only slightly enhanced. Finally, in a conical pore with large opening, the electric field is characterized by a maximum at the bottom of the pore, yielding a similar behavior for the ionization rate. These results demonstrate that the shape of the pore has a significantly influence on the electric field enhancement, and thus modifies the plasma properties.

Three-dimensional turbulent near-wall flows in streamwise corners: Current state and questions

NASA Astrophysics Data System (ADS)

Kornilov, V. I.

2017-10-01

Current advances in experimental and computational studies of three-dimensional (3-D) near-wall turbulent flows in streamwise corners (SC) including the boundary-layer transition are reviewed. The focus is the structure, properties and main regularities of such flows in a wide range of variable conditions and basic parameters. A variety of different kinds of near-wall streamwise corner flows is displayed. Analysis of approaches for modeling of the near-wall corner flow in laboratory experiment is given. The problem of simulation of such flows where some ambiguities remain is discussed. The main factors on the structure of the flow in streamwise corners are analyzed. Also, the effectiveness of flow control by streamwise vortices in the junction regions of aerodynamic surfaces is shown. Finally, some important properties of the modified near-wall turbulent corner flows which have been revealed experimentally, in particular, for the flow near the wing/body junction (WBJ), can be used as an attractive alternative for real applications.

Corner wetting during the vapor-liquid-solid growth of faceted nanowires

NASA Astrophysics Data System (ADS)

Spencer, Brian; Davis, Stephen

2016-11-01

We consider the corner wetting of liquid drops in the context of vapor-liquid-solid growth of nanowires. Specifically, we construct numerical solutions for the equilibrium shape of a liquid drop on top of a faceted nanowire by solving the Laplace-Young equation with a free boundary determined by mixed boundary conditions. A key result for nanowire growth is that for a range of contact angles there is no equilibrium drop shape that completely wets the corner of the faceted nanowire. Based on our numerical solutions we determine the scaling behavior for the singular surface behavior near corners of the nanowire in terms of the Young contact angle and drop volume.

Effects of the shape of the foil corners on the irradiation performance of U10Mo alloy based monolithic mini-plates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozaltun, Hakan; Medvedev, Pavel G

2015-06-01

Monolithic plate-type fuel is a fuel form being developed for high performance research and test reactors to minimize the use of enriched material. These fuel elements are comprised of a high density, low enrichment, U-Mo alloy based fuel foil, sandwiched between Zirconium liners and encapsulated in Aluminum cladding. The use of a high density fuel in a foil form presents a number of fabrication and operational concerns, such as: foil centering, flatness of the foil, fuel thickness variation, geometrical tilting, foil corner shape etc. To benchmark this new design, effects of various geometrical and operational variables on irradiation performance havemore » been evaluated. As a part of these series of sensitivity studies, the shape of the foil corners were studied. To understand the effects of the corner shapes of the foil on thermo-mechanical performance of the plates, a behavioral model was developed for a selected plate from RERTR-12 experiments (Plate L1P785). Both fabrication and irradiation processes were simulated. Once the thermo-mechanical behavior the plate is understood for the nominal case, the simulations were repeated for two additional corner shapes to observe the changes in temperature, displacement and stress-strain fields. The results from the fabrication simulations indicated that the foil corners do not alter the post-fabrication stress-strain magnitudes. Furthermore, the irradiation simulations revealed that post-fabrication stresses of the foil would be relieved very quickly in operation. While, foils with chamfered and filleted corners yielded stresses with comparable magnitudes, they are slightly lower in magnitudes, and provided a more favorable mechanical response compared with the foil with sharp corners.« less

Surface tension effects on fully developed liquid layer flow over a convex corner

NASA Astrophysics Data System (ADS)

Bhatti, Ifrah; Farid, Saadia; Ullah, Saif; Riaz, Samia; Faryad, Maimoona

2018-04-01

This investigation deals with the study of fully developed liquid layer flow along with surface tension effects, confronting a convex corner in the direction of fluid flow. At the point of interaction, the related equations are formulated using double deck structure and match asymptotic techniques. Linearized solutions for small angle are obtained analytically. The solutions corresponding to similar flow neglecting surface tension effects are also recovered as special case of our general solutions. Finally, the influence of pertinent parameters on the flow, as well as a comparison between models, are shown by graphical illustration.

Stress and Friction Distribution around Slab Corner in Continuous Casting Mold with Different Corner Structures

NASA Astrophysics Data System (ADS)

Yu, Sheng; Long, Mujun; Chen, Huabiao; Chen, Dengfu; Liu, Tao; Duan, Huamei; Cao, Junsheng

2018-06-01

The non-uniform friction and thermal stress in the mold are important as causes of the transverse cracks around strand corner. To analyze the stress distribution features around strand corner, a three-dimensional thermo-elastoplastic finite-element mold model with different corner structures (right-angle, big-chamfer, multi-chamfer, and fillet) was established. The temperature field in the mold was indirectly coupled through a three-dimensional fluid flow and heat transfer model. In addition, the non-uniform mold friction stress loaded on the strand surface was calculated through a friction model. The results show that the stress distribution on the shell is similar to the temperature distribution. The stress concentration appears in the strand corner and the lower part of wide face. The friction stress enhances the corner stress around the edge of the air-gap. For chamfered molds, the stress around the corner between the wide face and chamfer face is larger than that between the narrow face and chamfer face. Around the corner region, both the stress peak and the area of the large stress zone of the right-angle strand are the largest, while those of big-chamfered, multi-chamfered, and fillet strands decrease in that order. The stress peak position of the chamfered strands is closer to the mold exit than that of the right-angle strand. Compared with the use of the right-angle mold, the application of chamfered molds is able to reduce the stress concentration around the strand corner.

Stress and Friction Distribution around Slab Corner in Continuous Casting Mold with Different Corner Structures

NASA Astrophysics Data System (ADS)

Yu, Sheng; Long, Mujun; Chen, Huabiao; Chen, Dengfu; Liu, Tao; Duan, Huamei; Cao, Junsheng

2018-02-01

The non-uniform friction and thermal stress in the mold are important as causes of the transverse cracks around strand corner. To analyze the stress distribution features around strand corner, a three-dimensional thermo-elastoplastic finite-element mold model with different corner structures (right-angle, big-chamfer, multi-chamfer, and fillet) was established. The temperature field in the mold was indirectly coupled through a three-dimensional fluid flow and heat transfer model. In addition, the non-uniform mold friction stress loaded on the strand surface was calculated through a friction model. The results show that the stress distribution on the shell is similar to the temperature distribution. The stress concentration appears in the strand corner and the lower part of wide face. The friction stress enhances the corner stress around the edge of the air-gap. For chamfered molds, the stress around the corner between the wide face and chamfer face is larger than that between the narrow face and chamfer face. Around the corner region, both the stress peak and the area of the large stress zone of the right-angle strand are the largest, while those of big-chamfered, multi-chamfered, and fillet strands decrease in that order. The stress peak position of the chamfered strands is closer to the mold exit than that of the right-angle strand. Compared with the use of the right-angle mold, the application of chamfered molds is able to reduce the stress concentration around the strand corner.

Landing Trail in 3-D

NASA Technical Reports Server (NTRS)

2004-01-01

A three-dimensional color model created using data from the Mars Exploration Rover's panoramic camera shows images of airbag drag marks on the martian surface. The triangular rock in the upper left corner is approximately 20 centimeters (8 inches) tall. The meatball-shaped rock in the upper right corner is approximately 10 centimeters (4 inches) tall. The dark portion of the surface, or 'trough' is approximately 1 centimeter (0.4 inches) deep at its deepest point. This model is displayed using software developed by NASA's Ames Research Center.

A Unified Overset Grid Generation Graphical Interface and New Concepts on Automatic Gridding Around Surface Discontinuities

NASA Technical Reports Server (NTRS)

Chan, William M.; Akien, Edwin (Technical Monitor)

2002-01-01

For many years, generation of overset grids for complex configurations has required the use of a number of different independently developed software utilities. Results created by each step were then visualized using a separate visualization tool before moving on to the next. A new software tool called OVERGRID was developed which allows the user to perform all the grid generation steps and visualization under one environment. OVERGRID provides grid diagnostic functions such as surface tangent and normal checks as well as grid manipulation functions such as extraction, extrapolation, concatenation, redistribution, smoothing, and projection. Moreover, it also contains hyperbolic surface and volume grid generation modules that are specifically suited for overset grid generation. It is the first time that such a unified interface existed for the creation of overset grids for complex geometries. New concepts on automatic overset surface grid generation around surface discontinuities will also be briefly presented. Special control curves on the surface such as intersection curves, sharp edges, open boundaries, are called seam curves. The seam curves are first automatically extracted from a multiple panel network description of the surface. Points where three or more seam curves meet are automatically identified and are called seam corners. Seam corner surface grids are automatically generated using a singular axis topology. Hyperbolic surface grids are then grown from the seam curves that are automatically trimmed away from the seam corners.

Thales SESO's hollow and massive corner cube solutions

NASA Astrophysics Data System (ADS)

Fappani, Denis; Dahan, Déborah; Costes, Vincent; Luitot, Clément

2017-11-01

For Space Activities, more and more Corner Cubes, used as solution for retro reflection of light (telemetry and positioning), are emerging worldwide in different projects. Depending on the application, they can be massive or hollow Corner Cubes. For corners as well as for any kind of space optics, it usual that use of light/lightened components is always a baseline for purpose of mass reduction payloads. But other parameters, such as the system stability under severe environment, are also major issues, especially for the corner cube systems which require generally very tight angular accuracies. For the particular case of the hollow corner cube, an alternative solution to the usual cementing of the 3 reflective surfaces, has been developed with success in collaboration with CNES to guarantee a better stability and fulfill the weight requirements.. Another important parameter is the dihedral angles that have a great influence on the wavefront error. Two technologies can be considered, either a Corner Cubes array assembled in a very stable housing, or the irreversible adherence technology used for assembling the three parts of a cube. This latter technology enables in particular not having to use cement. The poster will point out the conceptual design, the manufacturing and control key-aspects of such corner cube assemblies as well as the technologies used for their assembling.

Higher-order topological insulators and superconductors protected by inversion symmetry

NASA Astrophysics Data System (ADS)

Khalaf, Eslam

2018-05-01

We study surface states of topological crystalline insulators and superconductors protected by inversion symmetry. These fall into the category of "higher-order" topological insulators and superconductors which possess surface states that propagate along one-dimensional curves (hinges) or are localized at some points (corners) on the surface. We provide a complete classification of inversion-protected higher-order topological insulators and superconductors in any spatial dimension for the 10 symmetry classes by means of a layer construction. We discuss possible physical realizations of such states starting with a time-reversal-invariant topological insulator (class AII) in three dimensions or a time-reversal-invariant topological superconductor (class DIII) in two or three dimensions. The former exhibits one-dimensional chiral or helical modes propagating along opposite edges, whereas the latter hosts Majorana zero modes localized to two opposite corners. Being protected by inversion, such states are not pinned to a specific pair of edges or corners, thus offering the possibility of controlling their location by applying inversion-symmetric perturbations such as magnetic field.

Growth of surface and corner cracks in beta-processed and mill-annealed Ti-6Al-4V

NASA Technical Reports Server (NTRS)

Bell, P. D.

1975-01-01

Empirical stress-intensity expressions were developed to relate the growth of cracks from corner flaws to the growth of cracks from surface flaws. An experimental program using beta-processed Ti-6Al-4V verified these expressions for stress ratios, R greater than or equal to 0. An empirical crack growth-rate expression which included stress-ratio and stress-level effects was also developed. Cracks grew approximately 10 percent faster in transverse-grain material than in longitudinal-grain material and at approximately the same rate in longitudinal-grain mill-annealed Ti-6Al-4V. Specimens having surface and corner cracks and made of longitudinal-grain, beta-processed material were tested with block loads, and increasing the stresses in a block did not significantly change the crack growth rates. Truncation of the basic ascending stress sequence within a block caused more rapid crack growth, whereas both the descending and low-to-high stress sequences slowed crack growth.

Gaseous Oxidized Mercury Dry Deposition Measurements in the FourCorners Area and Eastern Oklahoma, U.S.A.

EPA Science Inventory

Gaseous oxidized mercury (GOM) dry deposition measurements using surrogate surface passive samplers were collected in the Four Corners area and eastern Oklahoma from August, 2009–August, 2011. Using data from a six site area network, a characterization of the magnitude and spatia...

Capillary Corner Flows With Partial and Nonwetting Fluids

NASA Technical Reports Server (NTRS)

Bolleddula, D. A.; Weislogel, M. M.

2009-01-01

Capillary flow in containers or conduits with interior corners are common place in nature and industry. The majority of investigations addressing such flows solve the problem numerically in terms of a friction factor for flows along corners with contact angles below the Concus-Finn critical wetting condition for the particular conduit geometry of interest. This research effort provides missing numerical data for the flow resistance function F(sub i) for partially and nonwetting systems above the Concus-Finn condition. In such cases the fluid spontaneously de-wets the interior corner and often retracts into corner-bound drops. A banded numerical coefficient is desirable for further analysis and is achieved by careful selection of length scales x(sub s) and y(sub s) to nondimensionalize the problem. The optimal scaling is found to be identical to the wetting scaling, namely x(sub s) = H and y(sub s) = Htan (alpha), where H is the height from the corner to the free surface and a is the corner half-angle. Employing this scaling produces a relatively weakly varying flow resistance F(sub i) and for subsequent analyses is treated as a constant. Example solutions to steady and transient flow problems are provided that illustrate applications of this result.

Fabrication of corner cube array retro-reflective structure with DLP-based 3D printing technology

NASA Astrophysics Data System (ADS)

Riahi, Mohammadreza

2016-06-01

In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article.

Styles of Deformation on Either Side of a Ridge-Transform Intersection, Troodos Ophiolite, Cyprus

NASA Astrophysics Data System (ADS)

Titus, S.; Wagner, C.; Alexander, S. O.; Scott, C. P.; Davis, J. R.

2015-12-01

The Troodos ophiolite in Cyprus includes two orthogonal structures - the NS-striking Solea graben and the EW-striking Arakapas fault - that form a ridge-transform intersection. Sheeted dikes and gabbros are preserved on both the inside and outside corners providing a view of mid-crustal deformation in the system. We examine and model these patterns of deformation using existing map and paleomagnetic data combined with new rock magnetic data. The inside corner of the system has been well studied. The most notable feature is the changing orientation of sheeted dikes, which shift from NW- to NE- to E-striking with increasing proximity to the Arakapas fault. Paleomagnetic data from many studies, including our own, show declination anomalies that vary with distance from the ridge and the transform. The three principal axes from anisotropy of magnetic susceptibility (AMS) ellipsoids in the gabbros seem to be correlated with local sheeted dike orientations. The outside corner of the system has been less well studied. Sheeted dike orientations change more subtly; many are NS-striking and dip towards the Solea Graben, but near the inferred ridge-transform intersection, they are NNE-striking. Our new paleomagnetic data from 26 sites record declination and inclination anomalies that vary spatially within the outside corner. AMS data from the gabbros and sheeted dikes again seem loosely linked to sheeted dike orientations. To summarize, the structural and rock magnetic results on either side of the Solea Graben are distinct, confirming the idea that these rocks formed on different sides of a ridge-transform system. The paleomagnetic data yield insights about the styles of deformation following crystallization. The AMS data may yield insights about magmatic plumbing systems when combined systematically with paleomagnetic results. Our results from the outside corner show that patterns of deformation can be complex even on the non-plate boundary side of a ridge-transform system.

How books are wet by water

NASA Astrophysics Data System (ADS)

Kim, Jungchul; Kim, Ho-Young

2013-11-01

It is well known that a sheet of paper, a hydrophilic porous medium, imbibes water via capillary action. The wicking on two-dimensional sheets has no preferred direction, in general. However, when water is spilled on a book, a number of pieces of paper fastened together on one side, we notice that corners are wet first compared to the rest of the area. This is because the wicking along the sharp corner experiences weaker resistance than that into pores within paper. We study a simple model of this wicking dynamics in the context of the surface-tension-driven vertical rise of a liquid along a corner of folded paper. We find that the liquid height at the corner follows a power law different from that at the corner formed by impermeable walls (A. Ponomarenko, D. Quere, and C. Clanet, J. Fluid Mech. 666, 146-154, 2011). The difference is caused by the fact that the Laplace pressure that drives the vertical rise is independent of the liquid height on permeable walls (paper) while it increases with height at the corner of impermeable walls. The experiments are shown to be consistent with our theory.

Stress-intensity factor equations for cracks in three-dimensional finite bodies

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.; Raju, I. S.

1981-01-01

Empirical stress intensity factor equations are presented for embedded elliptical cracks, semi-elliptical surface cracks, quarter-elliptical corner cracks, semi-elliptical surface cracks at a hole, and quarter-elliptical corner cracks at a hole in finite plates. The plates were subjected to remote tensile loading. Equations give stress intensity factors as a function of parametric angle, crack depth, crack length, plate thickness, and where applicable, hole radius. The stress intensity factors used to develop the equations were obtained from three dimensional finite element analyses of these crack configurations.

Contact sheet recording with a self-acting negative air bearing

NASA Technical Reports Server (NTRS)

Muftu , Sinan (Inventor); Hinteregger, Hans F (Inventor)

2000-01-01

A flat head and a tape transport arrangement impart a wrap angle to the tape at the upstream corner of the head. The wrap angle, corner sharpness and tape stiffness are sufficient to cause a moving tape to form a hollow bump at the upstream corner, thereby creating a hollow into which entrained air can expand, causing a subambient pressure within and downstream of the bump. This pressure keeps the tape in contact with the head. It is created without the need for a groove or complex pressure relief slot(s). No contact pressure arises at the signal exchange site due to media wrap. The highest contact pressures are developed at a wrapped upstream corner. For a tape drive, traveling in both forward and reverse, the wrap can be at both the upstream and downstream (which is the reverse upstream) corners. Heads that are not flat can also be used, if the wrap angle relative to a main surface is sufficient and not too large. The wrapped head can also be used with rotating media, such as disks (floppy and hard) and rotating heads, such as helical wound heads for video recording. Multiple flat tape bearing surfaces can be separated by grooves and/or angles. Each flat can carry heads along one or more gap lines. Multiple adjacent narrow tracks can thus be written for extreme high track density recording.

Corner entanglement as a probe of quantum criticality

NASA Astrophysics Data System (ADS)

Witczak-Krempa, William; Bueno, Pablo; Myers, Robert C.

The entanglement entropy in many gapless quantum systems in 2+1D receives a contribution from corners in the entangling surface. It is characterized by a universal function a (θ) that depends non-trivially on the corner opening angle θ. Focusing on a large family of quantum critical theories with emergent Lorentz invariance (CFTs), we argue that the smooth limit a (θ ~ π) is entirely determined by the energy-density or stress tensor 2-point function coefficient. This explains recent results obtained via cutting edge simulations on the quantum critical Ising, XY and Heisenberg models. We also show how to extract the full thermal entropy of the quantum critical system using corner entanglement of the groundstate alone. ** Bueno, Myers, WK, Phys. Rev. Lett. (2015) Work supported by Perimeter Institute and NSERC.

Stress intensity factors for deep cracks emanating from the corner formed by a hole intersecting a plate surface

NASA Technical Reports Server (NTRS)

Mcgowan, J. J.; Smith, C. W.

1976-01-01

The stress intensity factors (SIFs) at the end points of flaws emanating from the corner formed by the intersection of a plate with a hole were determined using stress freezing photoelasticity and a numerical technique known as the Taylor series correction method to extract the SIF values from the photoelastic data. The geometries studied were crack depth to thickness ratios of about 0.2, 0.5, and 0.75; crack depth to crack length ratios of about 1.0 to 2.0; and crack length to hole radius ratios of about 0.5 to 2.0. The SIFs were determined at the intersection of the flaw border with the plate surface (KS) and with the edge of the hole (KH). It is shown that extension of a crack emanating from a corner of intersection of a hole with a plate under monotonically increasing load is not self-similar and that as the flaw depth increases, KH decreases and KS increases. Existing theories and design criteria significantly overestimate the SIF at both the hole and the surface except for shallow flaws at the hole and deep flaws at the surface.

The bulk, surface and corner free energies of the square lattice Ising model

NASA Astrophysics Data System (ADS)

Baxter, R. J.

2017-01-01

We use Kaufman’s spinor method to calculate the bulk, surface and corner free energies {f}{{b}},{f}{{s}},{f}{{s}}\\prime ,{f}{{c}} of the anisotropic square lattice zero-field Ising model for the ordered ferromagnetic case. For {f}{{b}},{f}{{s}},{f}{{s}}\\prime our results of course agree with the early work of Onsager, McCoy and Wu. We also find agreement with the conjectures made by Vernier and Jacobsen (VJ) for the isotropic case. We note that the corner free energy f c depends only on the elliptic modulus k that enters the working, and not on the argument v, which means that VJ’s conjecture applies for the full anisotropic model. The only aspect of this paper that is new is the actual derivation of f c, but by reporting all four free energies together we can see interesting structures linking them.

Global Source Parameters from Regional Spectral Ratios for Yield Transportability Studies

NASA Astrophysics Data System (ADS)

Phillips, W. S.; Fisk, M. D.; Stead, R. J.; Begnaud, M. L.; Rowe, C. A.

2016-12-01

We use source parameters such as moment, corner frequency and high frequency rolloff as constraints in amplitude tomography, ensuring that spectra of well-studied earthquakes are recovered using the ensuing attenuation and site term model. We correct explosion data for path and site effects using such models, which allows us to test transportability of yield estimation techniques based on our best source spectral estimates. To develop a background set of source parameters, we applied spectral ratio techniques to envelopes of a global set of regional distance recordings from over 180,000 crustal events. Corner frequencies and moment ratios were determined via inversion using all event pairs within predetermined clusters, shifting to absolute levels using independently determined regional and teleseismic moments. The moment and corner frequency results can be expressed as stress drop, which has considerable scatter, yet shows dramatic regional patterns. We observe high stress in subduction zones along S. America, S. Mexico, the Banda Sea, and associated with the Yakutat Block in Alaska. We also observe high stress at the Himalayan syntaxes, the Pamirs, eastern Iran, the Caspian, the Altai-Sayan, and the central African rift. Low stress is observed along mid ocean spreading centers, the Afar rift, patches of convergence zones such as Nicaragua, the Zagros, Tibet, and the Tien Shan, among others. Mine blasts appear as low stress events due to their low corners and steep rolloffs. Many of these anomalies have been noted by previous studies, and we plan to compare results directly. As mentioned, these results will be used to constrain tomographic imaging, but can also be used in model validation procedures similar to the use of ground truth in location problems, and, perhaps most importantly, figure heavily in quality control of local and regional distance amplitude measurements.

Corner-Cube Retroreflector Instrument for Advanced Lunar Laser Ranging

NASA Technical Reports Server (NTRS)

Turyshev, Slava G.; Folkner, William M.; Gutt, Gary M.; Williams, James G.; Somawardhana, Ruwan P.; Baran, Richard T.

2012-01-01

A paper describes how, based on a structural-thermal-optical-performance analysis, it has been determined that a single, large, hollow corner cube (170- mm outer diameter) with custom dihedral angles offers a return signal comparable to the Apollo 11 and 14 solid-corner-cube arrays (each consisting of 100 small, solid corner cubes), with negligible pulse spread and much lower mass. The design of the corner cube, and its surrounding mounting and casing, is driven by the thermal environment on the lunar surface, which is subject to significant temperature variations (in the range between 70 and 390 K). Therefore, the corner cube is enclosed in an insulated container open at one end; a narrow-bandpass solar filter is used to reduce the solar energy that enters the open end during the lunar day, achieving a nearly uniform temperature inside the container. Also, the materials and adhesive techniques that will be used for this corner-cube reflector must have appropriate thermal and mechanical characteristics (e.g., silica or beryllium for the cube and aluminum for the casing) to further reduce the impact of the thermal environment on the instrument's performance. The instrument would consist of a single, open corner cube protected by a separate solar filter, and mounted in a cylindrical or spherical case. A major goal in the design of a new lunar ranging system is a measurement accuracy improvement to better than 1 mm by reducing the pulse spread due to orientation. While achieving this goal, it was desired to keep the intensity of the return beam at least as bright as the Apollo 100-corner-cube arrays. These goals are met in this design by increasing the optical aperture of a single corner cube to approximately 170 mm outer diameter. This use of an "open" corner cube allows the selection of corner cube materials to be based primarily on thermal considerations, with no requirements on optical transparency. Such a corner cube also allows for easier pointing requirements, because there is no dependence on total internal reflection, which can fail off-axis.

Ion beam figuring technique used as final step in the manufacturing of the optics for the E-ELT

NASA Astrophysics Data System (ADS)

Ghigo, M.; Vecchi, G.; Basso, S.; Citterio, O.; Civitani, M.; Pareschi, G.; Sironi, G.

The INAF-Astronomical Observatory of Brera (INAF-OAB) is exploring the technical problems related to the ion beam figuring (IBF) of the Zerodur hexagonal mirrors (1.45 m corner to corner) of M1 for the European Extremely Large Telescope (E-ELT). As starting step a scaled down version mirror of the same material having size of 1 m corner to corner has been used to assess the relevant figuring problems. This specific mirror is spherical and has a radius of curvature of 3 m which allows a simple interferometric measurement setup. A mechanical support was designed to minimize its deformations due to gravity. The Ion Beam Figuring Facility used for this study has been recently completed in the Brera Observatory and has a figuring area of 170 cm x 140 cm. Aim of this study is the estimation and optimization of the time requested for the correction of the surface using also strategies to control the well-known thermal problems related to the Zerodur material. In this paper we report the results obtained figuring the 1 m corner-to-corner test segment.

Gold coatings for cube-corner retro-reflectors

NASA Astrophysics Data System (ADS)

Dligatch, Svetlana; Gross, Mark; Netterfield, Roger P.; Pereira, Nathan; Platt, Benjamin C.; Nemati, Bijan

2005-09-01

The Space Interferometry Mission (SIM) PlanetQuest is managed by the Jet Propulsion Laboratory for the National Aeronautics and Space Administration. SIM requires, among other things, high precision double cube-corner retroreflectors. A test device has recently been fabricated for this project with demanding specifications on the optical surfaces and gold reflective coatings. Several gold deposition techniques were examined to meet the stringent specifications on uniformity, optical properties, micro-roughness and surface quality. We report on a comparative study of optical performance of gold films deposited by resistive and e-beam pvaporation, including measurements of the scattering from the coated surfaces. The effects of oxygen bombardment and titanium under-layer on optical properties and adhesion were evaluated. The influence of surface preparation on the optical properties was examined also.

The dual boundary element formulation for elastoplastic fracture mechanics

NASA Astrophysics Data System (ADS)

Leitao, V.; Aliabadi, M. H.; Rooke, D. P.

1993-08-01

The extension of the dual boundary element method (DBEM) to the analysis of elastoplastic fracture mechanics (EPFM) problems is presented. The dual equations of the method are the displacement and the traction boundary integral equations. When the displacement equation is applied to one of the crack surfaces and the traction equation on the other, general mixed-mode crack problems can be solved with a single-region formulation. In order to avoid collocation at crack tips, crack kinks, and crack-edge corners, both crack surfaces are discretized with discontinuous quadratic boundary elements. The elastoplastic behavior is modeled through the use of an approximation for the plastic component of the strain tensor on the region expected to yield. This region is discretized with internal quadratic, quadrilateral, and/or triangular cells. A center-cracked plate and a slant edge-cracked plate subjected to tensile load are analyzed and the results are compared with others available in the literature. J-type integrals are calculated.

Initial stage oxidation on nano-trenched Si(1 0 0) surface

NASA Astrophysics Data System (ADS)

Sun, Yu; Liu, Yi-Lun; Izumi, Satoshi; Chen, Xue-Feng; Zhai, Zhi; Tian, Shao-Hua

2018-01-01

As the size of an electronic element shrinks to nanoscale, trench design of Si strongly influences the performance of related semiconductor devices. By reactive force field molecular dynamics (ReaxFF MD) simulation, the initial stage oxidation on nano-trenched Si(1 0 0) angled 60°, 90°, 120°, 150° under temperatures from 300 K to 1200 K has been studied. Inhomogeneous oxidation at the convex-concave corners of the Si surface was observed. In general, the initial oxidation process on the Si surface was that, firstly, the O atoms ballistically transported into surface, then a high O concentration induced compressive stress at the surface layers, which prevented further oxidation. Compared to the concave corner, the convex one contacted a larger volume of oxygen at the very beginning stage, leading an anisotropic absorption of O atoms. Afterwards, a critical compression was produced at both the convex and concave corners to limit the oxidation. As a result, an inhomogeneous oxide film grew on nano-trenched Si. Meanwhile, due to enhanced O transport and compression relaxation by increasing temperature, the inhomogeneous oxidation was more obvious under 1200 K. These present results explained the observed experimental phenomena on the oxidation of non-planar Si and provided an aspect on the design of nano-trenched electronic components in the semiconductor field.

Cornering and wear behavior of the Space Shuttle Orbiter main gear tire

NASA Technical Reports Server (NTRS)

Daugherty, Robert H.; Stubbs, Sandy M.

1987-01-01

One of the factors needed to describe the handling characteristics of the Space Shuttle Orbiter during the landing rollout is the response of the vehicle's tires to variations in load and yaw angle. An experimental investigation of the cornering characteristics of the Orbiter main gear tires was conducted at the NASA Langley Research Center Aircraft Landing Dynamics Facility. This investigation compliments earlier work done to define the Orbiter nose tire cornering characteristics. In the investigation, the effects of load and yaw angle were evaluated by measuring parameters such as side load and drag load, and obtaining measurements of aligning torque. Because the tire must operate on an extremely rough runway at the Shuttle Landing Facility at Kennedy Space Center (KSC), tests were also conducted to describe the wear behavior of the tire under various conditions on a simulated KSC runway surface. Mathematical models for both the cornering and the wear behavior are discussed.

See around the corner using active imaging

NASA Astrophysics Data System (ADS)

Steinvall, Ove; Elmqvist, Magnus; Larsson, Håkan

2011-11-01

This paper investigates the prospects of "seeing around the corner" using active imaging. A monostatic active imaging system offers interesting capabilities in the presence of glossy reflecting objects. Examples of such surfaces are windows in buildings and cars, calm water, signs and vehicle surfaces. During daylight it might well be possible to use mirrorlike reflection by the naked eye or a CCD camera for non-line of sight imaging. However the advantage with active imaging is that one controls the illumination. This will not only allow for low light and night utilization but also for use in cases where the sun or other interfering lights limit the non-line of sight imaging possibility. The range resolution obtained by time gating will reduce disturbing direct reflections and allow simultaneous view in several directions using range discrimination. Measurements and theoretical considerations in this report support the idea of using laser to "see around the corner". Examples of images and reflectivity measurements will be presented together with examples of potential system applications.

Numerical studies of singularity formation at free surfaces and fluid interfaces in two-dimensional Stokes flow

NASA Astrophysics Data System (ADS)

Pozrikidis, C.

1997-01-01

We consider the analytic structure of interfaces in several families of steady and unsteady two-dimensional Stokes flows, focusing on the formation of corners and cusps. Previous experimental and theoretical studies have suggested that, without surface tension, the interfaces spontaneously develop such singular points. We investigate whether and how corners and cusps actually develop in a time-dependent flow, and assess the stability of stationary cusped shapes predicted by previous authors. The motion of the interfaces is computed with high resolution using a boundary integral method for three families of flows. In the case of a bubble that is subjected to the family of straining flows devised by Antanovskii, we find that a stationary cusped shape is not likely to occur as the asymptotic limit of a transient deformation. Instead, the pointed ends of the bubble disintegrate in a process that is reminiscent of tip streaming. In the case of the flow due to an array of point-source dipoles immersed beneath a free surface, which is the periodic version of a flow proposed by Jeong & Moffatt, we find evidence that a cusped shape indeed arises as the result of a transient deformation. In the third part of the numerical study, we show that, under certain conditions, the free surface of a liquid film that is levelling under the action of gravity on a horizontal or slightly inclined surface develops an evolving corner or cusp. In certain cases, the film engulfs a small air bubble of ambient fluid to obtain a composite shape. The structure of a corner or a cusp in an unsteady flow does not have a unique shape, as it does at steady state. In all cases, a small amount of surface tension is able to prevent the formation of a singularity, but replacing the inviscid gas with a viscous liquid does not have a smoothing effect. The ability of the thin-film lubrication equation to produce mathematical singularities at the free surface of a levelling film is also discussed.

Capillary Driven Flows Along Differentially Wetted Interior Corners

NASA Technical Reports Server (NTRS)

Golliher, Eric L. (Technical Monitor); Nardin, C. L.; Weislogel, M. M.

2005-01-01

Closed-form analytic solutions useful for the design of capillary flows in a variety of containers possessing interior corners were recently collected and reviewed. Low-g drop tower and aircraft experiments performed at NASA to date show excellent agreement between theory and experiment for perfectly wetting fluids. The analytical expressions are general in terms of contact angle, but do not account for variations in contact angle between the various surfaces within the system. Such conditions may be desirable for capillary containment or to compute the behavior of capillary corner flows in containers consisting of different materials with widely varying wetting characteristics. A simple coordinate rotation is employed to recast the governing system of equations for flows in containers with interior corners with differing contact angles on the faces of the corner. The result is that a large number of capillary driven corner flows may be predicted with only slightly modified geometric functions dependent on corner angle and the two (or more) contact angles of the system. A numerical solution is employed to verify the new problem formulation. The benchmarked computations support the use of the existing theoretical approach to geometries with variable wettability. Simple experiments to confirm the theoretical findings are recommended. Favorable agreement between such experiments and the present theory may argue well for the extension of the analytic results to predict fluid performance in future large length scale capillary fluid systems for spacecraft as well as for small scale capillary systems on Earth.

Development of a Pavement Maintenance Management System. Volume 9. Development of Airfield Pavement Performance Prediction Models.

DTIC Science & Technology

1984-05-01

materials, traffic, and climate, were used to develop PCI and key distress prediction models for both asphalt-concrete- and jointed-concrete- surfaced...Predicted PCI for PCC and AC/PCC Pavements Using Model Presented in Section III ...... 35 31 Effect of PCC Thickness on the PCI as a Function of Age...of Corner Breaking Observed vs Predicted Percent of Corner Breaking Using Model Presented in Section III

Teaching Real Business Cycles to Undergraduates

ERIC Educational Resources Information Center

Brevik, Frode; Gartner, Manfred

2007-01-01

The authors review the graphical approach to teaching the real business cycle model introduced in Barro. They then look at where this approach cuts corners and suggest refinements. Finally, they compare graphical and exact models by means of impulse-response functions. The graphical models yield reliable qualitative results. Sizable quantitative…

High-Throughput Microfluidic Labyrinth for the Label-free Isolation of Circulating Tumor Cells.

PubMed

Lin, Eric; Rivera-Báez, Lianette; Fouladdel, Shamileh; Yoon, Hyeun Joong; Guthrie, Stephanie; Wieger, Jacob; Deol, Yadwinder; Keller, Evan; Sahai, Vaibhav; Simeone, Diane M; Burness, Monika L; Azizi, Ebrahim; Wicha, Max S; Nagrath, Sunitha

2017-09-27

We present "Labyrinth," a label-free microfluidic device to isolate circulating tumor cells (CTCs) using the combination of long loops and sharp corners to focus both CTCs and white blood cells (WBCs) at a high throughput of 2.5 mL/min. The high yield (>90%) and purity (600 WBCs/mL) of Labyrinth enabled us to profile gene expression in CTCs. As proof of principle, we used previously established cancer stem cell gene signatures to profile single cells isolated from the blood of breast cancer patients. We observed heterogeneous subpopulations of CTCs expressing genes for stem cells, epithelial cells, mesenchymal cells, and cells transitioning between epithelial and mesenchymal. Labyrinth offers a cell-surface marker-independent single-cell isolation platform to study heterogeneous CTC subpopulations. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of boundary-layer separation controllers on a desktop fume hood.

PubMed

Huang, Rong Fung; Chen, Jia-Kun; Hsu, Ching Min; Hung, Shuo-Fu

2016-10-02

A desktop fume hood installed with an innovative design of flow boundary-layer separation controllers on the leading edges of the side plates, work surface, and corners was developed and characterized for its flow and containment leakage characteristics. The geometric features of the developed desktop fume hood included a rearward offset suction slot, two side plates, two side-plate boundary-layer separation controllers on the leading edges of the side plates, a slanted surface on the leading edge of the work surface, and two small triangular plates on the upper left and right corners of the hood face. The flow characteristics were examined using the laser-assisted smoke flow visualization technique. The containment leakages were measured by the tracer gas (sulphur hexafluoride) detection method on the hood face plane with a mannequin installed in front of the hood. The results of flow visualization showed that the smoke dispersions induced by the boundary-layer separations on the leading edges of the side plates and work surface, as well as the three-dimensional complex flows on the upper-left and -right corners of the hood face, were effectively alleviated by the boundary-layer separation controllers. The results of the tracer gas detection method with a mannequin standing in front of the hood showed that the leakage levels were negligibly small (≤0.003 ppm) at low face velocities (≥0.19 m/s).

Drying in porous media with gravity-stabilized fronts: experimental results.

PubMed

Yiotis, A G; Salin, D; Tajer, E S; Yortsos, Y C

2012-08-01

In a recent paper [Yiotis et al., Phys. Rev. E 85, 046308 (2012)] we developed a model for the drying of porous media in the presence of gravity. It incorporated effects of corner film flow, internal and external mass transfer, and the effect of gravity. Analytical results were derived when gravity opposes drying and hence leads to a stable percolation drying front. In this paper, we test the theory using laboratory experiments. A series of isothermal drying experiments in glass bead packings saturated with volatile hydrocarbons is conducted. The transparent glass cells containing the packing allow for the visual monitoring of the phase distribution patterns below the surface, including the formation of liquid films, as the gaseous phase invades the pore space, and for the control of the thickness of the diffusive mass boundary layer over the packing. The experimental results agree very well with theory, provided that the latter is generalized to account for the effects of corner roundness in the film region (which was neglected in the theoretical part). We demonstrate the existence of an early constant rate period (CRP), which lasts as long as the films saturate the surface of the packing, and of a subsequent falling rate period (FRP), which begins practically after the detachment of the film tips from the external surface. During the CRP, the process is controlled by diffusion within the stagnant gaseous phase in the upper part of the cells, yielding a Stefan tube problem solution. During the FRP, the process is controlled by diffusion within the packing, with a drying rate inversely proportional to the observed position of the film tips in the cell. Theoretical and experimental results compare favorably for a specific value of the roundness of the films, which is found to be constant and equal to 0.2 for various conditions, and verify the theoretical dependence on the capillary Ca(f), Bond Bo, and Sherwood Sh numbers.

Molecular-Scale Structural Controls on Nanoscale Growth Processes: Step-Specific Regulation of Biomineral Morphology

NASA Astrophysics Data System (ADS)

Dove, P. M.; Davis, K. J.; De Yoreo, J. J.; Orme, C. A.

2001-12-01

Deciphering the complex strategies by which organisms produce nanocrystalline materials with exquisite morphologies is central to understanding biomineralizing systems. One control on the morphology of biogenic nanoparticles is the specific interactions of their surfaces with the organic functional groups provided by the organism and the various inorganic species present in the ambient environment. It is now possible to directly probe the microscopic structural controls on crystal morphology by making quantitative measurements of the dynamic processes occurring at the mineral-water interface. These observations can provide crucial information concerning the actual mechanisms of growth that is otherwise unobtainable through macroscopic techniques. Here we use in situ molecular-scale observations of step dynamics and growth hillock morphology to directly resolve roles of principal impurities in regulating calcite surface morphologies. We show that the interactions of certain inorganic as well as organic impurities with the calcite surface are dependent upon the molecular-scale structures of step-edges. These interactions can assume a primary role in directing crystal morphology. In calcite growth experiments containing magnesium, we show that growth hillock structures become modified owing to the preferential inhibition of step motion along directions approximately parallel to the [010]. Compositional analyses have shown that Mg incorporates at different levels into the two types of nonequivalent steps, which meet at the hillock corner parallel to [010]. A simple calculation of the strain caused by this difference indicates that we should expect a significant retardation at this corner, in agreement with the observed development of [010] steps. If the low-energy step-risers produced by these [010] steps is perpendicular to the c-axis as seems likely from crystallographic considerations, this effect provides a plausible mechanism for the elongated calcite crystal habits found in natural environments that contain magnesium. In a separate study, step-specific interactions are also found between chiral aspartate molecules and the calcite surface. The L and D- aspartate enantiomers exhibit structure preferences for the different types of step-risers on the calcite surface. These site-specific interactions result in the transfer of asymmetry from the organic molecule to the crystal surface through the formation of chiral growth hillocks and surface morphologies. These studies yield direct experimental insight into the molecular-scale structural controls on nanocrystal morphology in biomineralizing systems.

Experimental Investigation of SBLI to Unravel Inlet Unstart Physics

NASA Astrophysics Data System (ADS)

Funderburk, Morgan; Narayanaswamy, Venkateswaran

2016-11-01

The phenomenon of shock boundary layer interaction (SBLI) driven inlet unstart persists as one of the most significant problems facing supersonic ramjet/scramjet engines. In order to determine how the characteristics of the SBLI units specific to rectangular inlets evolve during an unstart event, an experimental investigation is made using surface streakline methods and pitot/wall pressure measurements in the vicinity of the floor and corner SBLI induced by a compression ramp in a rectangular channel. Mean and unsteady measurements were taken at a variety of shock strengths to simulate the evolution of the combustion-induced back pressure ratio during unstart. The freestream Mach number was also varied. Statistical correlation methods were used to determine the degree of interaction between the floor and corner SBLI with different flowfield locations for the various test conditions. Finally, comparison to a two-dimensional compression ramp SBLI was made to determine any modification caused by the introduction of the corner SBLI. Results indicate that the floor and corner SBLI transition from distinct units to members of a global separated flow with increasing back pressure, and that considerable modification of the floor SBLI by the corner flow occurs. AFOSR Grant FA9550-15-1-0296.

Measurement of corner separation zone response on a compression ramp to plasma actuation within the hypersonic boundary layer

NASA Astrophysics Data System (ADS)

Hedlund, Brock E.; Houpt, Alec W.; Gordeyev, Stanislav V.; Leonov, Sergey B.

2017-10-01

This study was performed to characterize the dominant frequencies present in the boundary layer uptsream of and in the corner separation zone of a compression surface in Mach 4.5 flow and to determine a control effect of transient plasma actuation on the boundary layer. Schlieren imaging was used to distinguish the corner separation zone for 20°, 25°, and 30° compression ramps mounted on flat plates. Spectra of the natural disturbances present in the boundary layer and separation zone were gathered using a high-speed Shack-Hartmann wavefront sensor and surface mounted PCBTM pressure sensors while varying flow parameters by adjusting total pressure, temperature, and ramp angle. Shallow cavity discharge plasma actuators were used as a high-frequency localized thermal forcing mechanism of the boundary layer. The plasma effect was negligible for forcing frequencies (50 kHz) below the natural dominant frequency (~55-80 kHz). High frequency perturbations that can promote the transition to turbulence were amplified when the plasma forcing frequency (100 kHz) was higher than the natural dominant frequency (~55-80 kHz). This technique can potentially be used for active control of hypersonic boundary layer transition and the supersonic flow structure on the compression surface.

Strength analysis of welded corners of PVC window profiles

NASA Astrophysics Data System (ADS)

Postawa, P.; Stachowiak, T.; Gnatowski, A.

2017-08-01

The article presents the results of researches which main purpose was to define the influence of welding parameters on strength of welded corners of PVC window profile. PVC profiles of a branded name GENEO® produced by Rehau Company were used for this research. The profiles were made by using a co-extrusion method. The surface of the profile was made of PVC mixture with no additives. Its main task was to get a smooth surface resistant to a smudge. The use of an unfilled polyester provides an aesthetic look and improves the resistance of extrudate to water getting into inner layers. The profile's inner layers have been filled up with glass fibre in order to improve its stiffness and mechanical properties. Window frames with cut corners used for this research, were produced on technological line of EUROCOLOR Company based in Pyskowice (Poland). The main goal of this analysis was to evaluate the influence of the main welding parameter (temperature upsetting) on hardness of welds we received in whole process. A universal testing machine was used for the research.

A New Technique for System-to-system Transfer of Surface Data

NASA Technical Reports Server (NTRS)

Sterling, M. W.; Lucius, M. E.; Gordon, W. J.

1985-01-01

The purpose is to describe a recently developed technique aimed at providing a universal interface between surface types. In brief, a software package was developed which functions a common denominator of CAD/CAM surface types. This software enable one to convert from any given surface representation to any other target representation. The tiles maintain the same slope continuity as the target surface gram, bicubic patches are used since they allow one to match point, slope, and twist vectors to the target surface. Thus, slopes can be continuous or discontinuous as they are on the target surface. The patches can be of lower order if desired. For example, if only point information is available, the patches produced will be bilinear; however, the number of patches required is likely to increase correspondingly. The patches can be of higher order although many systems will not accept patches of more than order four. The final result of the program is a rectangular grid of bicubic patches. The patches fit the target surface exactly at their corners. Also, the patch corners have the same tangent and twist vectors. Adjacent patches will have slope continuity, unless a discontinuity was indicated by the target surface.

42. GARRET, SOUTHWEST CORNER. The roof rafters have been notched ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

42. GARRET, SOUTHWEST CORNER. The roof rafters have been notched for shingle lath. In some places the notches and lath do not align. Attached to each joist are furring strips for the 1812 ceiling, allowing it to be lowered about one inch below the under surfaces of the joists. Note that the 1851 shingles were left in place when the 1873-74 tin roof was added. - Twelfth Street Meeting House, 20 South Twelfth Street, Philadelphia, Philadelphia County, PA

Rotary piston engine equipped with an improved air or fuel injection opening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasaki, Y.

An improved air or fuel injection opening is described for a rotary piston engine having a trochoidal inner surface of a center housing and an eccentrically rotating polygonal rotor. The air or fuel injection opening provided in a side housing wall is confined within a region limited so as to be outside of an outer envelope of traces of a side seal and inside an outer corner seal, with the opening having a contour smaller than that of the corner seal.

Free-surface phenomena under low- and zero-gravity conditions

NASA Technical Reports Server (NTRS)

Coles, D.

1985-01-01

An apparatus to measure contact angle was constructed to exploit the proposed internal-corner criterion. If 2 alfa is the internal angle between two intersecting vertical planes and gamma is the contact angle, a meniscus at the corner rises to a finite height if alfa + gamma pi/2 and to an infinite height if alfa + gamma pi/2. The apparatus operates by decreasing the angle alfa from pi/2 until the meniscus height changes abruptly. A number of liquids are tested on glass and plexiglas.

Distinctive styles of salt deformation formed by radial, convergent gliding into the sharp corners of the northeastern and northwestern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Bugti, M. N.; Mann, P.

2016-12-01

Previous workers have described the effects both downslope motion of salt and shale along straight margins and the more complex three-dimensional cases of downslope salt motion and deformation: 1) radial, divergent gliding off of coastal salients accompanied by strike-parallel extension increasing downslope; and 2) radial, convergent gliding into coastal reentrants or "corners" accompanied by strike-parallel contraction and differential loading increasing downslope. The northwestern Gulf of Mexico (GOM) forms a sharp, right-angle corner defined northeastern shelf of Mexico and South Texas and the shelf of the northern GOM; in a similar way the northwestern GOM forms a sharp, right-angle corner defined by the northern shelf of the GOM and the shelf of west Florida. Despite their physical separation by over 700 km, both the NW and NE GOM corners exhibit similar salt structures not observed in adjacent areas outside of the two corners. These corner-related features include: 1) detached salt stocks with positive surface expression; we interpret the detached salt stocks as reflecting a higher degree of radial convergent gliding and compression from three sides into the bend areas; 2) slightly elongate, surficial, diapir shapes with positive bathymetric expression and ranging in diameter from 2 to 22 km and localized fold axes with the long diapiric axes and fold axes aligned parallel to the bisector of the bend; these features are also attributed to radial convergent gliding into the bend areas; 3) zones of deformation at depth that occupy the corner areas: the northwestern GOM corresponds to the Port Isabel passive-margin fold and thrust belt and the northeastern GOM corresponds to the Mississippi Canyon fold and thrust belt; while these are older convergent features we propose that they are being reactivated by the corner-centric, gravity-driven process of radial, convergent gliding; and 4) salt welds in both corner areas record more intensive and complete salt extrusion of salt; outside the corner areas salt canopies and the lack of salt welds indicates a less convergent environment for salt. These two proposed areas of radial convergent gliding are compared to other examples of radial, convergent gliding described by previous workers in the Gulf of Lions and Santos basins.

Comparison of experimental surface pressures with theoretical predictions on twin two-dimensional convergent-divergent nozzles

NASA Technical Reports Server (NTRS)

Carlson, J. R.; Pendergraft, O. C., Jr.; Burley, J. R., II

1986-01-01

A three-dimensional subsonic aerodynamic panel code (VSAERO) was used to predict the effects of upper and lower external nozzle flap geometry on the external afterbody/nozzle pressure coefficient distributions and external nozzle drag of nonaxisymmetric convergent-divergent exhaust nozzles having parallel external sidewalls installed on a generic twin-engine high performance aircraft model. Nozzle static pressure coefficient distributions along the upper and lower surfaces near the model centerline and near the outer edges (corner) of the two surfaces were calculated, and nozzle drag was predicted using these surface pressure distributions. A comparison between the theoretical predictions and experimental wind tunnel data is made to evaluate the utility of the code in calculating the flow about these types of non-axisymmetric afterbody configurations. For free-stream Mach numbers of 0.60 and 0.90, the conditions where the flows were attached on the boattails yielded the best comparison between the theoretical predictions and the experimental data. For the Boattail terminal angles of greater than 15 deg., the experimental data for M = 0.60 and 0.90 indicated areas of separated flow, so the theoretical predictions failed to match the experimental data. Even though calculations of regions of separated flows are within the capabilities of the theoretical method, acceptable solutions were not obtained.

Dual boundary element formulation for elastoplastic fracture mechanics

NASA Astrophysics Data System (ADS)

Leitao, V.; Aliabadi, M. H.; Rooke, D. P.

1995-01-01

In this paper the extension of the dual boundary element method (DBEM) to the analysis of elastoplastic fracture mechanics (EPFM) problems is presented. The dual equations of the method are the displacement and the traction boundary integral equations. When the displacement equation is applied on one of the crack surfaces and the traction equation on the other, general mixed-mode crack problems can be solved with a single-region formulation. In order to avoid collocation at crack tips, crack kinks and crack-edge corners, both crack surfaces are discretized with discontinuous quadratic boundary elements. The elasto-plastic behavior is modelled through the use of an approximation for the plastic component of the strain tensor on the region expected to yield. This region is discretized with internal quadratic, quadrilateral and/or triangular cells. This formulation was implemented for two-dimensional domains only, although there is no theoretical or numerical limitation to its application to three-dimensional ones. A center-cracked plate and a slant edge-cracked plate subjected to tensile load are analysed and the results are compared with others available in the literature. J-type integrals are calculated.

Ion figuring of large prototype mirror segments for the E-ELT

NASA Astrophysics Data System (ADS)

Ghigo, M.; Vecchi, G.; Basso, S.; Citterio, O.; Civitani, M.; Mattaini, E.; Pareschi, G.; Sironi, G.

2014-07-01

At INAF-Astronomical Observatory of Brera a study is under way to explore the problems related to the ion beam figuring of full scale Zerodur hexagonal mirrors of M1 for the European Extremely Large Telescope (E-ELT), having size of 1.4 m corner to corner. During this study it is initially foreseen the figuring of a scaled down version mirror of the same material having size of 1 m corner to corner to assess the relevant figuring problems and issues. This specific mirror has a radius of curvature of 3 m, which allows for easy interferometric measurement. A mechanical support was designed to minimize its deformations due to the gravity. The Ion Beam Figuring Facility used for this study has been recently completed in the Brera Observatory and has a figuring area of 140 cm x 170 cm. It employs a Kaufman ion source having 50 mm grids mounted on three axis. This system has been designed and developed to be autonomous and self-monitoring during the figuring process. The software and the mathematical tools used to compute the dwell time solution have been developed at INAF-OAB as well. Aim of this study is the estimation and optimization of the time requested to correct the surface adopting strategies to mitigate the well-known thermal problems related to the Zerodur material. In this paper, the results obtained figuring the 1 m corner-to-corner test segment are reported.

Thermal fatigue behavior of H-13 die steel for aluminum die casting with various ion sputtered coatings

NASA Technical Reports Server (NTRS)

Nieh, C. Y.; Wallace, J. F.

1981-01-01

Sputtered coatings of Mo, W, Pt, Ag, Au, Co, Cr, Ni, Ag + Cu, Mo + Pt, Si3N4, A1N, Cr3C2, Ta5Si3, and ZrO2 were applied to a 2-inch-square, 7-inch-long thermal fatigue test specimen which was then internally water cooled and alternately immersed in molten aluminum and cooled in air. After 15,000 cycles the thermal fatigue cracks at the specimen corners were measured. Results indicate that a significant improvement in thermal fatigue resistance was obtained with platinum, molybdenum, and tungsten coatings. Metallographic examination indicates that the improvement in thermal fatigue resistance resulted from protection of the surface of the die steel from oxidation. The high yield strength and ductility of molybdenum and tungsten contributed to the better thermal fatigue resistance.

Surface cracks in a plate of finite width under tension or bending

NASA Technical Reports Server (NTRS)

Erdogan, F.; Boduroglu, H.

1984-01-01

The problem of a finite plate containing collinear surface cracks is considered and solved by using the line spring model with plane elasticity and Reissner's plate theory. The main focus is on the effect of interaction between two cracks or between cracks and stress-free plate boundaries on the stress intensity factors in an effort to provide extensive numerical results which may be useful in applications. Some sample results are obtained and are compared with the existing finite element results. Then the problem is solved for a single (internal) crack, two collinear cracks, and two corner cracks for wide range of relative dimensions. Particularly in corner cracks, the agreement with the finite element solution is surprisingly very good. The results are obtained for semi-elliptic and rectangular crack profiles which may, in practice, correspond to two limiting cases of the actual profile of a subcritically growing surface crack.

Surface cracks in a plate of finite width under extension or bending

NASA Technical Reports Server (NTRS)

Erdogan, F.; Boduroglu, H.

1984-01-01

In this paper the problem of a finite plate containing collinear surface cracks is considered. The problem is solved by using the line spring model with plane elasticity and Reissner's plate theory. The main purpose of the study is to investigate the effect of interaction between two cracks or between cracks and stress-free plate boundaries on the stress intensity factors and to provide extensive numerical results which may be useful in applications. First, some sample results are obtained and are compared with the existing finite element results. Then the problem is solved for a single (internal) crack, two collinear cracks and two corner cracks for wide range of relative dimensions. Particularly in corner cracks the agreement with the finite element solution is surprisingly very good. The results are obtained for semielliptic and rectangular crack profiles which may, in practice, correspond to two limiting cases of the actual profile of a subcritically growing surface crack.

Controlling surface-plasmon-polaritons launching with hot spot cylindrical waves in a metallic slit structure.

PubMed

Yao, Wenjie; Sun, Chengwei; Gong, Qihuang; Chen, Jianjun

2016-09-23

Plasmonic nanostructures, which are used to generate surface plasmon polaritons (SPPs), always involve sharp corners where the charges can accumulate. This can result in strong localized electromagnetic fields at the metallic corners, forming the hot spots. The influence of the hot spots on the propagating SPPs are investigated theoretically and experimentally in a metallic slit structure. It is found that the electromagnetic fields radiated from the hot spots, termed as the hot spot cylindrical wave (HSCW), can greatly manipulate the SPP launching in the slit structure. The physical mechanism behind the manipulation of the SPP launching with the HSCW is explicated by a semi-analytic model. By using the HSCW, unidirectional SPP launching is experimentally realized in an ultra-small metallic step-slit structure. The HSCW bridges the localized surface plasmons and the propagating surface plasmons in an integrated platform and thus may pave a new route to the design of plasmonic devices and circuits.

A new formulation of electromagnetic wave scattering using an on-surface radiation boundary condition approach

NASA Technical Reports Server (NTRS)

Kriegsmann, Gregory A.; Taflove, Allen; Umashankar, Koradar R.

1987-01-01

A new formulation of electromagnetic wave scattering by convex, two-dimensional conducting bodies is reported. This formulation, called the on-surface radiation condition (OSRC) approach, is based upon an expansion of the radiation condition applied directly on the surface of a scatterer. It is now shown that application of a suitable radiation condition directly on the surface of a convex conducting scatterer can lead to substantial simplification of the frequency-domain integral equation for the scattered field, which is reduced to just a line integral. For the transverse magnetic case, the integrand is known explicitly. For the transverse electric case, the integrand can be easily constructed by solving an ordinary differential equation around the scatterer surface contour. Examples are provided which show that OSRC yields computed near and far fields which approach the exact results for canonical shapes such as the circular cylinder, square cylinder, and strip. Electrical sizes for the examples are ka = 5 and ka = 10. The new OSRC formulation of scattering may present a useful alternative to present integral equation and uniform high-frequency approaches for convex cylinders larger than ka = 1. Structures with edges or corners can also be analyzed, although more work is needed to incorporate the physics of singular currents at these discontinuities. Convex dielectric structures can also be treated using OSRC.

Integrated surface management for pipeline construction: The Mid-America Pipeline Company Four Corners Project

Treesearch

Maria L. Sonett

1999-01-01

Integrated surface management techniques for pipeline construction through arid and semi-arid rangeland ecosystems are presented in a case history of a 412-mile pipeline construction project in New Mexico. Planning, implementation and monitoring for restoration of surface hydrology, soil stabilization, soil cover, and plant species succession are discussed. Planning...

Using an extreme bony prominence anatomical model to examine the influence of bed sheet materials and bed making methods on the distribution of pressure on the support surface.

PubMed

Iuchi, Terumi; Nakajima, Yukari; Fukuda, Moriyoshi; Matsuo, Junko; Okamoto, Hiroyuki; Sanada, Hiromi; Sugama, Junko

2014-05-01

Bed sheets generate high surface tension across the support surface and increase pressure to the body through a process known as the hammock effect. Using an anatomical model and a loading device characterized by extreme bony prominences, the present study compared pressure distributions on support surfaces across different bed making methods and bed sheet materials to determine the factors that influence pressure distribution. The model was placed on a pressure mapping system (CONFORMat; NITTA Corp., Osaka, Japan), and interface pressure was measured. Bed sheet elasticity and friction between the support surface and the bed sheets were also measured. For maximum interface pressure, the relative values of the following methods were higher than those of the control method, which did not use any bed sheets: cotton sheets with hospital corners (1.28, p = 0.02), polyester with no corners (1.29, p = 0.01), cotton with no corners (1.31, p = 0.003), and fitted polyester sheets (1.35, p = 0.002). Stepwise multiple regression analysis indicated that maximum interface pressure was negatively correlated with bed sheet elasticity (R(2) = 0.74). A statistically significant negative correlation was observed between maximum interface pressure and immersion depth, which was measured using the loading device (r = -0.40 and p = 0.04). We found that several combinations of bed making methods and bed sheet materials induced maximum interface pressures greater than those observed for the control method. Bed sheet materials influenced maximum interface pressure, and bed sheet elasticity was particularly important in reducing maximum interface pressure. Copyright © 2014 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

Stress intensity factors for deep cracks emanating from the corner formed by a hole intersecting a plate surface

NASA Technical Reports Server (NTRS)

Mcgowan, J. J.; Smith, C. W.

1974-01-01

A technique consisting of freezing photo-elasticity and a numerical method was used to obtain stress intensity factors for natural cracks emanating from the corner at which a hole intersects a plate surface. Geometries studied were: (1) crack depth to thickness ratios of approximately 0.2, (2) 0.5 and 0.75; (3) crack depth to crack length ratios of approximately 1.0 to 2.0; and (4) crack length to hole radius ratios of about 0.5 to 2.0. All final crack geometries were grown under monotonic loading and growth was not self similar, with most of the growth occuring through the thickness under remote extension. Stress intensity factors were determined at the intersection of the flaw border.

3D Thermal/Mechanical Evolution Of The Plate Boundary Corner In SE Alaska

NASA Astrophysics Data System (ADS)

Barker, A.; Koons, P.; Upton, P.; Pavlis, T.; Chapman, J.

2007-12-01

The St Elias orogen of southeast Alaska forms part of an actively deforming plate boundary corner. The corner accommodates the transition from a strike-slip lateral boundary to a convergent normal boundary. Oblique convergence of the Yakutat microplate into the corner generates early stage tectonic characteristics associated with other corner systems (e.g. Himalayan Eastern Syntaxis). In combination with the high relief, the extreme erosive processes of the region redistribute crustal material, partition tectonic strain, and influence the advection of deep crustal material. The evolution of the convergent corner is investigated using 3D numerical models and sandbox analog models. Preliminary model results indicate the deformation partitions into a narrow two-sided orogen along the lateral boundary. The pattern transitions into a wider zone of shortening bounded by inboard and outboard directed thrusts along the frontal boundary. The inclusion of erosion boundary conditions leads to nascent tectonic aneurysm behavior, involving increased strain localization and focused vertical advection of deep crustal material. Thermal models, using the 3D velocity field from these mechanical solutions, show a vertical deflection (towards the surface) of isotherms beneath the eroding region. Sensitivity of the aneurysm behavior is related to the efficiency of the imposed erosion rate (i.e. greater erosion rates led to greater bedrock uplift rates). Higher erosion rates are localized within zones containing major glacier systems in SE Alaska: Bering Glacier, Bagley Icefield, Malaspina Glacier, and Seward Glacier. Combined thermal/mechanical solutions identify the glacier valleys as rheological weakspots, defined by localized strain and differential advection of deep crustal material.

Study of the Effect of Mold Corner Shape on the Initial Solidification Behavior of Molten Steel Using Mold Simulator

NASA Astrophysics Data System (ADS)

Lyu, Peisheng; Wang, Wanlin; Long, Xukai; Zhang, Kaixuan; Gao, Erzhuo; Qin, Rongshan

2018-02-01

The chamfered mold with a typical corner shape (angle between the chamfered face and hot face is 45 deg) was applied to the mold simulator study in this paper, and the results were compared with the previous results from a well-developed right-angle mold simulator system. The results suggested that the designed chamfered structure would increase the thermal resistance and weaken the two-dimensional heat transfer around the mold corner, causing the homogeneity of the mold surface temperatures and heat fluxes. In addition, the chamfered structure can decrease the fluctuation of the steel level and the liquid slag flow around the meniscus at mold corner. The cooling intensities at different longitudinal sections of shell are close to each other due to the similar time-average solidification factors, which are 2.392 mm/s1/2 (section A-A: chamfered center), 2.372 mm/s1/2 (section B-B: 135 deg corner), and 2.380 mm/s1/2 (section D-D: face), respectively. For the same oscillation mark (OM), the heights of OM roots at different positions (profile L1 (face), profile L2 (135 deg corner), and profile L3 (chamfered center)) are very close to each other. The average value of height difference (HD) between two OMs roots for L1 and L2 is 0.22 mm, and for L2 and L3 is 0.38 mm. Finally, with the help of metallographic examination, the shapes of different hooks were also discussed.

Alignment of smectic mesogens over engineered surfaces

NASA Astrophysics Data System (ADS)

Chandran, Achu; Joshi, Tilak; Khanna, P. K.; Mehta, Dalip. S.; Haranath, D.; Biradar, Ashok M.

2017-07-01

The alignment of smectic C* liquid crystals (LCs) has been manipulated over and near different surfaces such as bare glass, indium tin oxide (ITO) coated glass, patterned glass, and near spacers. The LC sample cell is made of one ITO coated glass plate and other having striped ITO with a Mylar spacer maintaining a finite cell gap between them. Laser scribing is used to make striped ITO, while the scribed area results in the formation of the patterned glass surface. The geometry of the cell is such that overlapped ITO lie in the middle and spacers are placed in the two extreme corners of the cell. The alignment of LC is found to be homeotropic over the ITO coated glass, while it is planar near the spacer. Interestingly, a transition from homeotropic to planar is observed while moving away from the middle towards either corner of the cell. The origin of both types of alignment in the same cell has been explained by considering the difference in the surface energy of different surfaces. This work renders new advancement towards the manipulation of LC alignment using different surfaces and interfaces for advanced electro-optical and photonic devices based on LCs.

43 CFR 3863.1-3 - Data to be filed in support of application.

Code of Federal Regulations, 2012 CFR

2012-10-01

... possible: If the claim be for a deposit of placer gold, there must be stated the yield per pan, or cubic... deposits of placer gold. If it be a building stone or other deposit than gold claimed under the placer laws..., giving their dimensions, value, and the course and distance thereof to the nearest corner of the public...

43 CFR 3863.1-3 - Data to be filed in support of application.

Code of Federal Regulations, 2013 CFR

2013-10-01

... possible: If the claim be for a deposit of placer gold, there must be stated the yield per pan, or cubic... deposits of placer gold. If it be a building stone or other deposit than gold claimed under the placer laws..., giving their dimensions, value, and the course and distance thereof to the nearest corner of the public...

43 CFR 3863.1-3 - Data to be filed in support of application.

Code of Federal Regulations, 2014 CFR

2014-10-01

... possible: If the claim be for a deposit of placer gold, there must be stated the yield per pan, or cubic... deposits of placer gold. If it be a building stone or other deposit than gold claimed under the placer laws..., giving their dimensions, value, and the course and distance thereof to the nearest corner of the public...

43 CFR 3863.1-3 - Data to be filed in support of application.

Code of Federal Regulations, 2011 CFR

2011-10-01

... possible: If the claim be for a deposit of placer gold, there must be stated the yield per pan, or cubic... deposits of placer gold. If it be a building stone or other deposit than gold claimed under the placer laws..., giving their dimensions, value, and the course and distance thereof to the nearest corner of the public...

Hydraulic conductivity of variably saturated porous media: Film and corner flow in angular pore space

NASA Astrophysics Data System (ADS)

Tuller, Markus; Or, Dani

2001-05-01

Many models for hydraulic conductivity of partially saturated porous media rely on oversimplified representation of the pore space as a bundle of cylindrical capillaries and disregard flow in liquid films. Recent progress in modeling liquid behavior in angular pores of partially saturated porous media offers an alternative framework. We assume that equilibrium liquid-vapor interfaces provide well-defined and stable boundaries for slow laminar film and corner flow regimes in pore space comprised of angular pores connected to slit-shaped spaces. Knowledge of liquid configuration in the assumed geometry facilitates calculation of average liquid velocities in films and corners and enables derivation of pore-scale hydraulic conductivity as a function of matric potential. The pore-scale model is statistically upscaled to represent hydraulic conductivity for a sample of porous medium. Model parameters for the analytical sample-scale expressions are estimated from measured liquid retention data and other measurable medium properties. Model calculations illustrate the important role of film flow, whose contribution dominates capillary flow (in full pores and corners) at relatively high matric potentials (approximately -100 to -300 J kg-1, or -1 to 3 bars). The crossover region between film and capillary flow is marked by a significant change in the slope of the hydraulic conductivity function as often observed in measurements. Model predictions are compared with the widely applied van Genuchten-Mualem model and yield reasonable agreement with measured retention and hydraulic conductivity data over a wide range of soil textural classes.

Cornering and wear characteristics of the Space Shuttle Orbiter nose-gear tire

NASA Technical Reports Server (NTRS)

Davis, Pamela A.; Stubbs, Sandy M.; Vogler, William A.

1989-01-01

Tests of the Space Shuttle Orbiter nose-gear tire have been completed at NASA Langley's Aircraft Landing Dynamics Facility. The purpose of these tests was to determine the cornering and wear characteristics of the Space Shuttle Orbiter nose-gear tire under realistic operating conditions. The tire was tested on a simulated Kennedy Space Center runway surface at speeds from 100 to 180 kts. The results of these tests defined the cornering characteristics which included side forces and associated side force friction coefficient over a range of yaw angles from 0 deg to 12 deg. Wear characteristics were defined by tire tread and cord wear over a yaw angle range of 0 deg to 4 deg under dry and wet runway conditions. Wear characteristics were also defined for a 15 kt crosswind landing with two blown right main-gear tires and nose-gear steering engaged.

Gold coatings for cube-corner retro-reflectors

NASA Technical Reports Server (NTRS)

Dligatch, Svetlana; Gross, Mark; Netterfield, Roger P.; Pereira, Nathan; Platt, Benjamin C.; Nemati, Bijan

2005-01-01

We report on a comparative study of optical performance of gold films deposited by resistive and e-beam evaporation, including measurements of the scattering from the coated surfaces. The effects of oxygen bombardment and titanium under-layer on optical properties and adhesion were evaluated. The influence of surface preparation on the optical properties was examined also.

Thermal Performance of Surface Wick Structures.

NASA Astrophysics Data System (ADS)

Chen, Yongkang; Tavan, Noel; Baker, John; Melvin, Lawrence; Weislogel, Mark

2010-03-01

Microscale surface wick structures that exploit capillary driven flow in interior corners have been designed. In this study we examine the interplay between capillary flow and evaporative heat transfer that effectively reduces the surface temperature. The tests are performed by raising the surface temperature to various levels before the flow is introduced to the surfaces. Certainly heat transfer weakens the capillary driven flow. It is observed, however, the surface temperature can be reduced significantly. The effects of geometric parameters and interconnectivity are to be characterized to identify optimal configurations.

Numerical investigation of sliding drops on an inclined surface

NASA Astrophysics Data System (ADS)

Legendre, Dominique; Pedrono, Annaig; Interface Group Team

2017-11-01

Despite it apparent simplicity, the behavior of a drop on an inclined solid surface is far to be properly reproduced by numerical simulation. It involves static, hysteresis and dynamic contact line behaviors. Depending on the fluid properties, the hysteresis and the wall inclination, different drop shapes (rounded, corner or pearling drop) can be observed. The 3D numerical simulations of sliding droplets presented in this work are based on a Volume of Fluid (VoF) solver without any interface reconstruction developed in the JADIM code. The surface tension is solved using the classical CSF (Continuum Surface Force) model and a sub grid model is used to describe under hysteresis conditions both the shape, the dissipation of the non resolved scales of a moving contact line. Numerical simulations are compared with the experiments of. The agreement with experiments is found to be very good for both he critical angle of inclination for siding as well as for the specific shapes: rounded, corner and pearling drops. The simulations have been used to extend the range of hysteresis covered by the experiments.

STS-55 Earth observation of the Timor Sea

NASA Technical Reports Server (NTRS)

1993-01-01

STS-55 Earth observation taken from Columbia, Orbiter Vehicle (OV) 102, shows the Timor Sea along the south coast of Timor. The sunglint pattern shows a sharp boundary in sea surface temperature, with cooler water along the coast and warmer water offshore. The sunglint brightness reveals water surface roughness with bright indicating smooth water and dark representing rough water. Cooler water is smoother because it acts to stabilize the atmospheric boundary layer, while the warm water acts to destabilize the atmosphere. Another indication of water temperature is the cloud pattern. Advection within the atmosphere as a result of warming at the sea surface forms low-level clouds with the small, popcorn-like appearance seen in upper right corner of the photograph. The cool water, on the other hand, is relatively free of the popcorn-like clouds. The distribution of the clouds indicates that the wind is blowing toward the upper right corner of the photograph. Also note the line of low-level

Diffraction of a plane wave by a three-dimensional corner

NASA Technical Reports Server (NTRS)

Ting, L.; Kung, F.

1971-01-01

By the superposition of the conical solution for the diffraction of a plane pulse by a three dimensional corner, the solution for a general incident plane wave is constructed. A numerical program is presented for the computation of the pressure distribution on the surface due to an incident plane wave of any wave form and at any incident angle. Numerical examples are presented to show the pressure signature at several points on the surface due to incident wave with a front shock wave, two shock waves in succession, or a compression wave with same peak pressure. The examples show that when the distance of a point on the surface from the edges or the vertex is comparable to the distance for the front pressure raise to reach the maximum, the peak pressure at that point can be much less than that given by a regular reflection, because the diffracted wave front arrives at that point prior to the arrival of the peak incident wave.

Performance of an aircraft tire under cyclic braking and of a currently operational antiskid braking system

NASA Technical Reports Server (NTRS)

Tanner, J. A.

1972-01-01

An experimental investigation was conducted to study the performance of an aircraft tire under cyclic braking conditions and to study the performance of a currently operational aircraft antiskid braking system. Dry, damp, and flooded runway surface conditions were used in the investigation. The results indicated that under cyclic braking conditions the braking and cornering-force friction coefficients may be influenced by fluctuations in the vertical load, flexibility in the wheel support, and the spring coupling between the wheel and the tire-pavement interface. The cornering capability was shown to be negligible at wheel slip ratios well below a locked-wheel skid under all test surface conditions. The maximum available brake-force friction coefficient was shown to be dependent upon the runway surface condition, upon velocity, and, for wet runways, upon tire differences. Moderate reductions in vertical load and brake system pressure did not significantly affect the overall wet-runway performance of the tire.

Three Dimensional Viscous Flow Field in an Axial Flow Turbine Nozzle Passage

NASA Technical Reports Server (NTRS)

Ristic, D.; Lakshminarayana, B.

1997-01-01

The objective of this investigation is experimental and computational study of three dimensional viscous flow field in the nozzle passage of an axial flow turbine stage. The nozzle passage flow field has been measured using a two sensor hot-wire probe at various axial and radial stations. In addition, two component LDV measurements at one axial station (x/c(sum m) = 0.56) were performed to measure the velocity field. Static pressure measurements and flow visualization, using a fluorescent oil technique, were also performed to obtain the location of transition and the endwall limiting streamlines. A three dimensional boundary layer code, with a simple intermittency transition model, was used to predict the viscous layers along the blade and endwall surfaces. The boundary layers on the blade surface were found to be very thin and mostly laminar, except on the suction surface downstream of 70% axial chord. Strong radial pressure gradient, especially close to the suction surface, induces strong cross flow components in the trailing edge regions of the blade. On the end-walls the boundary layers were much thicker, especially near the suction corner of the casing surface, caused by secondary flow. The secondary flow region near the suction-casing surface corner indicates the presence of the passage vortex detached from the blade surface. The corner vortex is found to be very weak. The presence of a closely spaced rotor downstream (20% of the nozzle vane chord) introduces unsteadiness in the blade passage. The measured instantaneous velocity signal was filtered using FFT square window to remove the periodic unsteadiness introduced by the downstream rotor and fans. The filtering decreased the free stream turbulence level from 2.1% to 0.9% but had no influence on the computed turbulence length scale. The computation of the three dimensional boundary layers is found to be accurate on the nozzle passage blade surfaces, away from the end-walls and the secondary flow region. On the nozzle passage endwall surfaces the presence of strong pressure gradients and secondary flow limit the validity of the boundary layer code.

Heat Transfer in Conical Corner and Short Superelliptical Transition Ducts

NASA Technical Reports Server (NTRS)

Poinsatte, Philip; Thurman, Douglas; Hippensteele, Steven

2008-01-01

Local surface heat transfer measurements were experimentally mapped using a transient liquid-crystal heat-transfer technique on the surface of two circular-to-rectangular transition ducts. One has a transition cross section defined by conical corners (Duct 1) and the other by an elliptical equation with changing coefficients (Duct 2). Duct 1 has a length-to-diameter ratio of 0.75 and an exit plane aspect ratio of 1.5. Duct 2 has a length-to-diameter ratio of 1.0 and an exit plane aspect ratio of 2.9. Test results are reported for various inlet-diameter-based Reynolds numbers ranging from 0.45 106 to 2.39 106 and two freestream turbulence intensities of about 1 percent, which is typical of wind tunnels, and up to 16 percent, which may be more typical of real engine conditions.

Capillary Flow in an Interior Corner

NASA Technical Reports Server (NTRS)

Weislogel, Mark Milton

1996-01-01

The design of fluids management processes in the low-gravity environment of space requires an accurate model and description of capillarity-controlled flow in containers of irregular geometry. Here we consider the capillary rise of a fluid along an interior corner of a container following a rapid reduction in gravity. The analytical portion of the work presents an asymptotic formulation in the limit of a slender fluid column, slight surface curvature along the corner, small inertia, and low gravity. New similarity solutions are found and a list of closed form expressions is provided for flow rate and column length. In particular, it is found that the flow is proportional to t(exp 1/2) for a constant height boundary condition, t(exp 2/5) for a spreading drop, and t(exp 3/5) for constant flow. In the experimental portion of the work, measurements from a 2.2s drop tower are reported. An extensive data set, collected over a previously unexplored range of flow parameters, includes estimates of repeatability and accuracy, the role of inertia and column slenderness, and the effects of corner angle, container geometry, and fluid properties. Comprehensive comparisons are made which illustrate the applicability of the analytic results to low-g fluid systems design.

Source parameters of the 1999 Osa peninsula (Costa Rica) earthquake sequence from spectral ratios analysis

NASA Astrophysics Data System (ADS)

Verdecchia, A.; Harrington, R. M.; Kirkpatrick, J. D.

2017-12-01

Many observations suggest that duration and size scale in a self-similar way for most earthquakes. Deviations from the expected scaling would suggest that some physical feature on the fault surface influences the speed of rupture differently at different length scales. Determining whether differences in scaling exist between small and large earthquakes is complicated by the fact that duration estimates of small earthquakes are often distorted by travel-path and site effects. However, when carefully estimated, scaling relationships between earthquakes may provide important clues about fault geometry and the spatial scales over which it affects fault rupture speed. The Mw 6.9, 20 August 1999, Quepos earthquake occurred on the plate boundary thrust fault along southern Costa Rica margin where the subducting seafloor is cut by numerous normal faults. The mainshock and aftershock sequence were recorded by land and (partially by) ocean bottom (OBS) seismic arrays deployed as part of the CRSEIZE experiment. Here we investigate the size-duration scaling of the mainshock and relocated aftershocks on the plate boundary to determine if a change in scaling exists that is consistent with a change in fault surface geometry at a specific length scale. We use waveforms from 5 short-period land stations and 12 broadband OBS stations to estimate corner frequencies (the inverse of duration) and seismic moment for several aftershocks on the plate interface. We first use spectral amplitudes of single events to estimate corner frequencies and seismic moments. We then adopt a spectral ratio method to correct for non-source-related effects and refine the corner frequency estimation. For the spectral ratio approach, we use pairs of earthquakes with similar waveforms (correlation coefficient > 0.7), with waveform similarity implying event co-location. Preliminary results from single spectra show similar corner frequency values among events of 0.5 ≤ M ≤ 3.6, suggesting a decrease in static stress drop with magnitude. Our next step is to refine corner frequency estimates using spectral ratios to see if the trend in corner frequency persists with small events, and to extend the magnitude range of the estimations using land-based recordings of the mainshock and two largest aftershocks, which occurred prior to the Osa array deployment.

Modified TMAH based etchant for improved etching characteristics on Si{1 0 0} wafer

NASA Astrophysics Data System (ADS)

Swarnalatha, V.; Narasimha Rao, A. V.; Ashok, A.; Singh, S. S.; Pal, P.

2017-08-01

Wet bulk micromachining is a popular technique for the fabrication of microstructures in research labs as well as in industry. However, increasing the throughput still remains an active area of research, and can be done by increasing the etching rate. Moreover, the release time of a freestanding structure can be reduced if the undercutting rate at convex corners can be improved. In this paper, we investigate a non-conventional etchant in the form of NH2OH added in 5 wt% tetramethylammonium hydroxide (TMAH) to determine its etching characteristics. Our analysis is focused on a Si{1 0 0} wafer as this is the most widely used in the fabrication of planer devices (e.g. complementary metal oxide semiconductors) and microelectromechanical systems (e.g. inertial sensors). We perform a systematic and parametric analysis with concentrations of NH2OH varying from 5% to 20% in step of 5%, all in 5 wt% TMAH, to obtain the optimum concentration for achieving improved etching characteristics including higher etch rate, undercutting at convex corners, and smooth etched surface morphology. Average surface roughness (R a), etch depth, and undercutting length are measured using a 3D scanning laser microscope. Surface morphology of the etched Si{1 0 0} surface is examined using a scanning electron microscope. Our investigation has revealed a two-fold increment in the etch rate of a {1 0 0} surface with the addition of NH2OH in the TMAH solution. Additionally, the incorporation of NH2OH significantly improves the etched surface morphology and the undercutting at convex corners, which is highly desirable for the quick release of microstructures from the substrate. The results presented in this paper are extremely useful for engineering applications and will open a new direction of research for scientists in both academic and industrial laboratories.

Analysis of Condensation Heat Transfer Performance in Curved Triangle Microchannels Based on the Volume of Fluid Method

NASA Astrophysics Data System (ADS)

Lei, Yuchuan; Chen, Zhenqian; Shi, Juan

2017-12-01

Numerical simulations of condensation heat transfer of R134a in curved triangle microchannels with various curvatures are proposed. The model is established on the volume of fluid (VOF) approach and user-defined routines which including mass transfer at the vapor-liquid interface and latent heat. Microgravity operating condition is assumed in order to highlight the surface tension. The predictive accuracy of the model is assessed by comparing the simulated results with available correlations in the literature. Both an increased mass flux and the decreased hydraulic diameter could bring better heat transfer performance. No obvious effect of the wall heat flux is observed in condensation heat transfer coefficient. Changes in geometry and surface tension lead to a reduction of the condensate film thickness at the sides of the channel and accumulation of the condensate film at the corners of the channel. Better heat transfer performance is obtained in the curved triangle microchannels over the straight ones, and the performance could be further improved in curved triangle microchannels with larger curvatures. The minimum film thickness where most of the heat transfer process takes place exists near the corners and moves toward the corners in curved triangle microchannels with larger curvatures.

Composite View from Phoenix Lander

NASA Image and Video Library

2009-07-02

This mosaic of images from the Surface Stereo Imager camera on NASA Phoenix Mars Lander shows several trenches dug by Phoenix, plus a corner of the spacecraft deck and the Martian arctic plain stretching to the horizon.

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2013 CFR

2013-07-01

... tile, surface hardened steel, glass block, live rock, face brick or hollow title. (5) Fasteners shall... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into...

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2012 CFR

2012-07-01

... tile, surface hardened steel, glass block, live rock, face brick or hollow title. (5) Fasteners shall... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into...

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2011 CFR

2011-07-01

... tile, surface hardened steel, glass block, live rock, face brick or hollow title. (5) Fasteners shall... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into...

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2014 CFR

2014-07-01

... tile, surface hardened steel, glass block, live rock, face brick or hollow title. (5) Fasteners shall... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into...

Photogrammetric Method and Software for Stream Planform Identification

NASA Astrophysics Data System (ADS)

Stonedahl, S. H.; Stonedahl, F.; Lohberg, M. M.; Lusk, K.; Miller, D.

2013-12-01

Accurately characterizing the planform of a stream is important for many purposes, including recording measurement and sampling locations, monitoring change due to erosion or volumetric discharge, and spatial modeling of stream processes. While expensive surveying equipment or high resolution aerial photography can be used to obtain planform data, our research focused on developing a close-range photogrammetric method (and accompanying free/open-source software) to serve as a cost-effective alternative. This method involves securing and floating a wooden square frame on the stream surface at several locations, taking photographs from numerous angles at each location, and then post-processing and merging data from these photos using the corners of the square for reference points, unit scale, and perspective correction. For our test field site we chose a ~35m reach along Black Hawk Creek in Sunderbruch Park (Davenport, IA), a small, slow-moving stream with overhanging trees. To quantify error we measured 88 distances between 30 marked control points along the reach. We calculated error by comparing these 'ground truth' distances to the corresponding distances extracted from our photogrammetric method. We placed the square at three locations along our reach and photographed it from multiple angles. The square corners, visible control points, and visible stream outline were hand-marked in these photos using the GIMP (open-source image editor). We wrote an open-source GUI in Java (hosted on GitHub), which allows the user to load marked-up photos, designate square corners and label control points. The GUI also extracts the marked pixel coordinates from the images. We also wrote several scripts (currently in MATLAB) that correct the pixel coordinates for radial distortion using Brown's lens distortion model, correct for perspective by forcing the four square corner pixels to form a parallelogram in 3-space, and rotate the points in order to correctly orient all photos of the same square location. Planform data from multiple photos (and multiple square locations) are combined using weighting functions that mitigate the error stemming from the markup-process, imperfect camera calibration, etc. We have used our (beta) software to mark and process over 100 photos, yielding an average error of only 1.5% relative to our 88 measured lengths. Next we plan to translate the MATLAB scripts into Python and release their source code, at which point only free software, consumer-grade digital cameras, and inexpensive building materials will be needed for others to replicate this method at new field sites. Three sample photographs of the square with the created planform and control points

Instability mechanisms in microfluidics and nanomaterials

NASA Astrophysics Data System (ADS)

Thamida, Sunil Kumar

Recent scientific advances in chemical engineering are leading to synthesis of micro-scale and nano-scale functional devices and materials. However, optimal design and performance of these devices and materials requires a fundamental under standing of the interfacial phenomena at micro-scale and nano-scale. Due to new physical forces unique to small scales, new phenomena appear that are unexpected at large scales. A study of new interfacial patterns that arise from various interfacial instabilities at these scales is carried out in this dissertation. Nevertheless, interfacial patterns ranging from micro to macro scale are ubiquitous in multiphase systems and material synthesis involving a surface reaction. Fractal break up of a thin viscous oil film dewetting between two separating plates is studied experimentally. Unlike the classical patterns of pores and dendrites, it forms a fractal pattern like a branching tree with its origin at the center of the circular film. Lubrication theory is extended to such a fractal geometry, which is unlike the circular geometry of a classical dewetting problem. A power law scaling is obtained for the radial air finger length distribution to construct an idealized Cayley fractal structure. Our theory yields a result that the plate detach time decreases by half in the limit of a fully fractal pattern that is confirmed experimentally. Nanopore formation in anodized alumina is also found to bear similarities to the interfacial pattern formation of the dewetting film between two separating plates. The oxide layer formed on the aluminum during the initial stages of anodizing is found to be unstable to perturbations on the scale of a few nanometers and hence it leads to the nanopore formation. A linear stability analysis of the dual interfacial dynamics followed by a leading mode projection produces a single evolution equation for the pores. Numerical simulations of the nonlinear model reveals the hexagonal packing and self-organization dynamics of the pores. In microfluidic devices, electrokinetic flow produces spiral vortices and corner aggregation of particles and proteins at an inner corner of a channel turn that is unexplained by the short ranged DLVO forces. Field leakage effect due to the non perfectly insulating wall reveals a nonlinear singular and ejecting slip velocity condition at an acute angled sharp corner. The complete flow streamlines, vortices and the corner entrainment are revealed by conformal mapping, harmonic analysis and numerical simulation using Lattice-Boltzmann-Method (LBM). The method of hodograph transform developed for the earlier projects to solve the Laplace equation is also applied to find optimum shapes of dispersion free turns for electro-osmotic microfluidic channels.

Avalanching strain dynamics during the hydriding phase transformation in individual palladium nanoparticles

NASA Astrophysics Data System (ADS)

Ulvestad, A.; Welland, M. J.; Collins, S. S. E.; Harder, R.; Maxey, E.; Wingert, J.; Singer, A.; Hy, S.; Mulvaney, P.; Zapol, P.; Shpyrko, O. G.

2015-12-01

Phase transitions in reactive environments are crucially important in energy and information storage, catalysis and sensors. Nanostructuring active particles can yield faster charging/discharging kinetics, increased lifespan and record catalytic activities. However, establishing the causal link between structure and function is challenging for nanoparticles, as ensemble measurements convolve intrinsic single-particle properties with sample diversity. Here we study the hydriding phase transformation in individual palladium nanocubes in situ using coherent X-ray diffractive imaging. The phase transformation dynamics, which involve the nucleation and propagation of a hydrogen-rich region, are dependent on absolute time (aging) and involve intermittent dynamics (avalanching). A hydrogen-rich surface layer dominates the crystal strain in the hydrogen-poor phase, while strain inversion occurs at the cube corners in the hydrogen-rich phase. A three-dimensional phase-field model is used to interpret the experimental results. Our experimental and theoretical approach provides a general framework for designing and optimizing phase transformations for single nanocrystals in reactive environments.

Avalanching strain dynamics during the hydriding phase transformation in individual palladium nanoparticles

PubMed Central

Ulvestad, A.; Welland, M. J.; Collins, S. S. E.; Harder, R.; Maxey, E.; Wingert, J.; Singer, A.; Hy, S.; Mulvaney, P.; Zapol, P.; Shpyrko, O. G.

2015-01-01

Phase transitions in reactive environments are crucially important in energy and information storage, catalysis and sensors. Nanostructuring active particles can yield faster charging/discharging kinetics, increased lifespan and record catalytic activities. However, establishing the causal link between structure and function is challenging for nanoparticles, as ensemble measurements convolve intrinsic single-particle properties with sample diversity. Here we study the hydriding phase transformation in individual palladium nanocubes in situ using coherent X-ray diffractive imaging. The phase transformation dynamics, which involve the nucleation and propagation of a hydrogen-rich region, are dependent on absolute time (aging) and involve intermittent dynamics (avalanching). A hydrogen-rich surface layer dominates the crystal strain in the hydrogen-poor phase, while strain inversion occurs at the cube corners in the hydrogen-rich phase. A three-dimensional phase-field model is used to interpret the experimental results. Our experimental and theoretical approach provides a general framework for designing and optimizing phase transformations for single nanocrystals in reactive environments. PMID:26655832

Localised surface plasmon-like resonance generated by microwave electromagnetic waves in pipe defects

NASA Astrophysics Data System (ADS)

Alobaidi, Wissam M.; Nima, Zeid A.; Sandgren, Eric

2018-01-01

Localised surface plasmon (LSP)-like resonance phenomena were simulated in COMSOL Multiphysics™, and the electric field enhancement was evaluated in eight pipe defects using the microwave band from 1.80 to 3.00 GHz and analysed by finite element analysis (FEA). The simulation was carried out, in each defect case, on a pipe that has 762 mm length and 152.4 mm inner diameter, and 12.7 mm pipe wall thickness. Defects were positioned in the middle of the pipe and were named as follows; SD: Square Defect, FCD: fillet corner defect, FD: fillet defect, HCD: half circle defect, TCD: triangle corner defect, TD: triangle defect, ZD: zigzag defect, GD: gear defect. The LSP electric field, and scattering parametric (S21, and S11) waves were evaluated in all cases and found to be strongly dependent on the size and the shape of the defect rather than the pipe and or the medium materials.

Elements of the Chicxulub Impact Structure as Revealed in SRTM and Surface GPS Topographic Data

NASA Technical Reports Server (NTRS)

Kinsland, Gary L.; Sanchez, Gary; Kobrick, Michael; Cardador, Manuel Hurtado

2003-01-01

Pope et al. [1] utilized the elevations from the Petroleos Mexicanos (PEMEX) gravity data files to show that the main component of the surface expression of the Chicxulub Impact Structure is a roughly semi-circular, lowrelief depression about 90 km in diameter. They also identified other topographic features and the elements of the buried impact, which possibly led to the development of these features. These are summarized in Table 1. Kinsland et al. [2] presented a connection between these topographic anomalies, small gravity anomalies and buried structure of the impact. Very recently we have acquired digital topography data from NASA s Shuttle Radar Topography Mission (SRTM). Our subset covers 6 square degrees from 20deg N 91degW to 22deg N 88degW (corner to corner) with a pixel size of about 90m. This area includes all of the identified portion of the crater on land.

Stress-intensity factors for small surface and corner cracks in plates

NASA Technical Reports Server (NTRS)

Raju, I. S.; Atluri, S. N.; Newman, J. C., Jr.

1988-01-01

Three-dimensional finite-element and finite-alternating methods were used to obtain the stress-intensity factors for small surface and corner cracked plates subjected to remote tension and bending loads. The crack-depth-to-crack-length ratios (a/c) ranged from 0.2 to 1 and the crack-depth-to-plate-thickness ratios (a/t) ranged from 0.05 to 0.2. The performance of the finite-element alternating method was studied on these crack configurations. A study of the computational effort involved in the finite-element alternating method showed that several crack configurations could be analyzed with a single rectangular mesh idealization, whereas the conventional finite-element method requires a different mesh for each configuration. The stress-intensity factors obtained with the finite-element-alternating method agreed well (within 5 percent) with those calculated from the finite-element method with singularity elements.

Diffraction of a shock wave by a compression corner; regular and single Mach reflection

NASA Technical Reports Server (NTRS)

Vijayashankar, V. S.; Kutler, P.; Anderson, D.

1976-01-01

The two dimensional, time dependent Euler equations which govern the flow field resulting from the injection of a planar shock with a compression corner are solved with initial conditions that result in either regular reflection or single Mach reflection of the incident planar shock. The Euler equations which are hyperbolic are transformed to include the self similarity of the problem. A normalization procedure is employed to align the reflected shock and the Mach stem as computational boundaries to implement the shock fitting procedure. A special floating fitting scheme is developed in conjunction with the method of characteristics to fit the slip surface. The reflected shock, the Mach stem, and the slip surface are all treated as harp discontinuities, thus, resulting in a more accurate description of the inviscid flow field. The resulting numerical solutions are compared with available experimental data and existing first-order, shock-capturing numerical solutions.

Quantitative analysis and predictive engineering of self-rolling of nanomembranes under anisotropic mismatch strain

NASA Astrophysics Data System (ADS)

Chen, Cheng; Song, Pengfei; Meng, Fanchao; Li, Xiao; Liu, Xinyu; Song, Jun

2017-12-01

The present work presents a quantitative modeling framework for investigating the self-rolling of nanomembranes under different lattice mismatch strain anisotropy. The effect of transverse mismatch strain on the roll-up direction and curvature has been systematically studied employing both analytical modeling and numerical simulations. The bidirectional nature of the self-rolling of nanomembranes and the critical role of transverse strain in affecting the rolling behaviors have been demonstrated. Two fabrication strategies, i.e., third-layer deposition and corner geometry engineering, have been proposed to predictively manipulate the bidirectional rolling competition of strained nanomembranes, so as to achieve controlled, unidirectional roll-up. In particular for the strategy of corner engineering, microfabrication experiments have been performed to showcase its practical application and effectiveness. Our study offers new mechanistic knowledge towards understanding and predictive engineering of self-rolling of nanomembranes with improved roll-up yield.

Toward an Empirically-Based Parametric Explosion Spectral Model

DTIC Science & Technology

2010-09-01

estimated (Richards and Kim, 2009). This archive could potentially provide 200 recordings of explosions at Semipalatinsk Test Site of the former Soviet...estimates of explosion yield, and prior work at the Nevada Test Site (NTS) (e.g., Walter et al., 1995) has found that explosions in weak materials have...2007). Corner frequency scaling of regional seismic phases for underground nuclear explosions at the Nevada Test Site , Bull. Seismol. Soc. Am. 97

Corner detection and sorting method based on improved Harris algorithm in camera calibration

NASA Astrophysics Data System (ADS)

Xiao, Ying; Wang, Yonghong; Dan, Xizuo; Huang, Anqi; Hu, Yue; Yang, Lianxiang

2016-11-01

In traditional Harris corner detection algorithm, the appropriate threshold which is used to eliminate false corners is selected manually. In order to detect corners automatically, an improved algorithm which combines Harris and circular boundary theory of corners is proposed in this paper. After detecting accurate corner coordinates by using Harris algorithm and Forstner algorithm, false corners within chessboard pattern of the calibration plate can be eliminated automatically by using circular boundary theory. Moreover, a corner sorting method based on an improved calibration plate is proposed to eliminate false background corners and sort remaining corners in order. Experiment results show that the proposed algorithms can eliminate all false corners and sort remaining corners correctly and automatically.

Coining seal

DOEpatents

Mancebo, Lloyd

1976-01-01

A bakeable high pressure-vacuum seal is provided in which an inductile sealing element having a butterfly shaped crosssection with protruding sharp edges at each of the four corners, is sandwiched between two ductile sealing elements, the sandwiched assembly then being compressed between the surfaces of the flange elements of a high pressure or high vacuum vessel to coin the ductile sealing element into the surface of the inductile sealing element as well as the surfaces of the flange elements.

The gravitational potential of a homogeneous polyhedron or don't cut corners

NASA Technical Reports Server (NTRS)

Werner, Robert A.

1994-01-01

A polyhedron can model irregularly shaped objects such as asteroids, comet nuclei, and small planetary satellites. With minor effort, such a model can incorporate important surface features such as large craters. Here we develop closed-form expressions for the exterior gravitational potential and acceleration components due to a constant-density polyhedron. An equipotential surface of Phobos is illustrated.

Stress intensity factors for deep cracks emanating from the corner formed by a hole intersecting a plate surface

NASA Technical Reports Server (NTRS)

Mcgowan, J. J.; Smith, C. W.

1974-01-01

A technique consisting of a marriage between stress freezing photoelasticity and a numerical method was used to obtain stress intensity factors for natural cracks emanating from the corner at which a hole intersects a plate surface. Geometrics studied were: crack depth to thickness ratios of approximately 0.2, 0.5, and 0.75; crack depth to crack length ratios of approximately 1.0 to 2.0. All final crack geometries were grown under monotonic loading and growth was not self similar with most of the growth occurring through the thickness under remote extension. Stress intensity plate surface K sub s factors were determined at the intersection of the flaw border with the plate surface K sub s and with the edge of the hole K sub h. Results showed that for the relatively shallow flaws K sub h approximately equal to 1.5 K sub s, for the moderately deep flaws K sub h approximately equal to K sub s, and for the deep flaws K sub h approximately equal to 0.5 K sub s, revealing a severe sensitivity of K to flaw geometry.

29 CFR 1915.135 - Powder actuated fastening tools.

Code of Federal Regulations, 2010 CFR

2010-07-01

... into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into... 2×4 inch lumber to a concrete surface, fasteners of greater than 7/32 inch shank diameter shall not...

49 CFR 238.233 - Interior fittings and surfaces.

Code of Federal Regulations, 2010 CFR

2010-10-01

... determined by the railroad: (1) Longitudinal: 8g; (2) Vertical: 4g; and (3) Lateral: 4g. (c) Other interior..., except seats, shall be recessed or flush-mounted. (e) Sharp edges and corners in a locomotive cab and a...

Mines in the Four Corners anticipate growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buchsbaum, L.

2008-02-15

Productive mines in the southwest deplete reserves, while the government drags its heels on new power projects. Production in Arizona and New Mexico has fallen 18% over the last four years to 34.1 million tons. With Chevron Mining's McKinley mine rapidly depleting its reserves the industry will continue to contract. In the last three years at least three large mines in the Four Corners have terminated operations. Three others remain captive operations: BHP Billiton's San Juan Underground and Navajo Surface operations and Peabody Energy's Kayenta surface mine. In 2006 the Black Mesa mine stopped producing coal. These four mines aremore » isolated from the national railways. Peabody's new El Segundo surface mine near Grants, NM is increasing production. If the planned $3 billion Desert Rock coal-fired power plant is built this will present a new market for the Navajo mine. The article gives details about the state of the aforementioned mines and of the new King II coal mine on the northern periphery of the San Juan basin and discusses the state of plans for the Desert Rock Energy Project. 5 photos.« less

Optimizing Vacuum Assisted Resin Transfer Moulding (VARTM) Processing Parameters to Improve Part Quality

NASA Astrophysics Data System (ADS)

Polowick, Christopher

The Low Cost Composites (LCC) group at Carleton University is studying out-of-autoclave composite manufacturing processes such as Vacuum Assisted Resin Transfer Moulding (VARTM) and Closed Cavity Bag Moulding (CCBM). These processes are used to produce inexpensive and high performance components for the GeoSurv II, an Unmanned Aerial Vehicle (UAV) being developed at Carleton University. This research has focused on optimizing VARTM processing parameters to reduce the weight and improve the strength and surface finish of GeoSurv II composite components. A simulation was developed to model resin flow through in VARTM infusions and was used to simulate mould filling and resin emptying of the GeoSurv II inverted V-empennage and mission avionics hatch. The resin infusion schemes of these parts were designed to ensure full preform resin saturation, and minimize thickness variations. An experimental study of the effects of the presence of a corner on composite thickness, void content, and strength was conducted. It was found that inside corners result in local increases in thickness and void content due to poor preform compaction. A novel bagging technique was developed to improve corner compaction, and this technique was shown to reduce thickness variability and void content. The strength, void content, and thickness variation were found to be heavily dependent on corner radius, with corner radii greater than 6.4 mm displaying the greatest improvement in performance for the layups considered. The design of the empennage and hatch mould incorporated the results of this study to improve the quality of these components.

Investigation of Materials for Boundary Layer Control in a Supersonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Braafladt, Alexander; Lucero, John M.; Hirt, Stefanie M.

2013-01-01

During operation of the NASA Glenn Research Center 15- by 15-Centimeter Supersonic Wind Tunnel (SWT), a significant, undesirable corner flow separation is created by the three-dimensional interaction of the wall and floor boundary layers in the tunnel corners following an oblique-shock/ boundary-layer interaction. A method to minimize this effect was conceived by connecting the wall and floor boundary layers with a radius of curvature in the corners. The results and observations of a trade study to determine the effectiveness of candidate materials for creating the radius of curvature in the SWT are presented. The experiments in the study focus on the formation of corner fillets of four different radii of curvature, 6.35 mm (0.25 in.), 9.525 mm (0.375 in.), 12.7 mm (0.5 in.), and 15.875 mm (0.625 in.), based on the observed boundary layer thickness of 11.43 mm (0.45 in.). Tests were performed on ten candidate materials to determine shrinkage, surface roughness, cure time, ease of application and removal, adhesion, eccentricity, formability, and repeatability. Of the ten materials, the four materials which exhibited characteristics most promising for effective use were the heavy body and regular type dental impression materials, the basic sculpting epoxy, and the polyurethane sealant. Of these, the particular material which was most effective, the heavy body dental impression material, was tested in the SWT in Mach 2 flow, and was observed to satisfy all requirements for use in creating the corner fillets in the upcoming experiments on shock-wave/boundary-layer interaction.

Effect of cutting fluids and cutting conditions on surface integrity and tool wear in turning of Inconel 713C

NASA Astrophysics Data System (ADS)

Hikiji, R.

2018-01-01

The trend toward downsizing of engines helps to increase the number of turbochargers around Europe. As for the turbocharger, the temperature of the exhaust gas is so high that the parts made of nickel base super alloy Inconel 713C are used as high temperature strength metals. External turning of Inconel 713C which is used as the actual automotive parts was carried out. The effect of the cutting fluids and cutting conditions on the surface integrity and tool wear was investigated, considering global environment and cost performance. As a result, in the range of the cutting conditions used this time, when the depth of cut was small, the good surface integrity and tool life were obtained. However, in the case of the large corner radius, it was found that the more the cutting length increased, the more the tool wear increased. When the cutting length is so large, the surface integrity and tool life got worse. As for the cutting fluids, it was found that the synthetic type showed better performance in the surface integrity and tool life than the conventional emulsion. However, it was clear that the large corner radius made the surface roughness and tool life good, but it affected the size error etc. in machining the workpiece held in a cantilever style.

Ground-water appraisal of the Fishkill-Beacon area, Dutchess County, New York

USGS Publications Warehouse

Snavely, Deborah S.

1980-01-01

The most productive aquifers in the Fishkill-Beacon area, Dutchess County, N.Y., are the sand and gravel beds in the northeast corner of the area and along the valleys of Fishkill and Clove Creeks. The average yield of these aquifers to wells is 190 gal/min (gallons per minute). The most productive bedrock aquifer is limestone, which yields an average of about 150 gal/min. Shale and granite each yield an average of less than 35 gal/min. About 4 billion gallons of available ground water is estimated to be in storage in the sand and gravel aquifers in the area. The area withdraws an average of 3.3 Mgal/d (million gallons per day) of water in June, July, and August and 2 Mgal/d during the remainder of the year. (USGS)

Comparison of tool feed influence in CNC polishing between a novel circular-random path and other pseudo-random paths.

PubMed

Takizawa, Ken; Beaucamp, Anthony

2017-09-18

A new category of circular pseudo-random paths is proposed in order to suppress repetitive patterns and improve surface waviness on ultra-precision polished surfaces. Random paths in prior research had many corners, therefore deceleration of the polishing tool affected the surface waviness. The new random path can suppress velocity changes of the polishing tool and thus restrict degradation of the surface waviness, making it suitable for applications with stringent mid-spatial-frequency requirements such as photomask blanks for EUV lithography.

Capillary surfaces in a wedge: Differing contact angles

NASA Technical Reports Server (NTRS)

Concus, Paul; Finn, Robert

1994-01-01

The possible zero-gravity equilibrium configurations of capillary surfaces u(x, y) in cylindrical containers whose sections are (wedge) domains with corners are investigated mathematically, for the case in which the contact angles on the two sides of the wedge may differ. In such a situation the behavior can depart in significant qualitative ways from that for which the contact angles on the two sides are the same. Conditions are described under which such qualitative changes must occur. Numerically computed surfaces are depicted to indicate the behavior.

Structural changes caused by H 2 adsorption on the Si(111)7 × 7 surface

NASA Astrophysics Data System (ADS)

Wolff, S. H.; Wagner, S.; Gibson, J. M.; Loretto, D.; Robinson, I. K.; Bean, J. C.

1990-12-01

Structural changes caused by the adsorption of molecular hydrogen adsorption onto the Si(111)7 × 7 surface reconstruction are quantified using the first structure parameter refinement on transmission electron diffraction (TED) data. We find that initial adsorption of molecular hydrogen onto the Si(111)7 × 7 surface causes a preferential decrease in the occupancy of the center adatoms. Further adsorption of hydrogen results in the breaking of the dimer bonds and the removal of the corner adatoms.

Detail, corner pilaster remnant, gable return on facade, Our Corner ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail, corner pilaster remnant, gable return on facade, Our Corner Saloon, view to northeast (210mm lens with electronic flash fill) - Our Corner Saloon, 301 First Street, Eureka, Humboldt County, CA

Strong and weak second-order topological insulators with hexagonal symmetry and ℤ3 index

NASA Astrophysics Data System (ADS)

Ezawa, Motohiko

2018-06-01

We propose second-order topological insulators (SOTIs) whose lattice structure has a hexagonal symmetry C6. We start with a three-dimensional weak topological insulator constructed on a stacked triangular lattice, which has only side topological surface states. We then introduce an additional mass term which gaps out the side surface states but preserves the hinge states. The resultant system is a three-dimensional SOTI. The bulk topological quantum number is shown to be the Z3 index protected by inversion time-reversal symmetry I T and rotoinversion symmetry I C6 . We obtain three phases: trivial, strong, and weak SOTI phases. We argue the origin of these two types of SOTIs. A hexagonal prism is a typical structure respecting these symmetries, where six topological hinge states emerge at the side. The building block is a hexagon in two dimensions, where topological corner states emerge at the six corners in the SOTI phase. Strong and weak SOTIs are obtained when the interlayer hopping interaction is strong and weak, respectively.

Computational Simulation of High Energy Density Plasmas

DTIC Science & Technology

2009-10-30

the imploding liner. The PFS depends on a lithium barrier foil slowing the advance of deuterium up the coaxial gun to the corner. There the plasma ...the coaxial gun section, and Figure 4 shows the physical state of the plasma just prior to pinch. Figure 5 shows neutron yield reaching 1014 in this...details the channel geometry between the center cylinder and coaxial gas gun . The deuterium injection starts when the pressure of the deuterium gas in

Conjunctive-use optimization model of the Mississippi River Valley alluvial aquifer of Southeastern Arkansas

USGS Publications Warehouse

Czarnecki, John B.; Clark, Brian R.; Stanton, Gregory P.

2003-01-01

The Mississippi River Valley alluvial aquifer is a water-bearing assemblage of gravels and sands that underlies about 32,000 square miles of Missouri, Kentucky, Tennessee, Mississippi, Louisiana, and Arkansas. Because of the heavy demands placed on the aquifer, several large cones of depression have formed in the potentiometric surface, resulting in lower well yields and degraded water quality in some areas. A ground-water flow model of the alluvial aquifer was previously developed for an area covering 3,826 square miles, extending south from the Arkansas River into the southeastern corner of Arkansas, parts of northeastern Louisiana, and western Mississippi. The flow-model results indicated that continued ground-water withdrawals at rates commensurate with those of 1997 could not be sustained indefinitely without causing water levels to decline below half the original saturated thickness of the aquifer. Conjunctive-use optimization modeling was applied to the flow model of the alluvial aquifer to develop withdrawal rates that could be sustained relative to the constraints of critical ground-water area designation. These withdrawal rates form the basis for estimates of sustainable yield from the alluvial aquifer and from rivers specified within the alluvial aquifer model. A management problem was formulated as one of maximizing the sustainable yield from all ground-water and surface-water withdrawal cells within limits imposed by plausible withdrawal rates, and within specified constraints involving hydraulic head and streamflow. Steady-state conditions were selected because the maximized withdrawals are intended to represent sustainable yield of the system (a rate that can be maintained indefinitely).One point along the Arkansas River and one point along Bayou Bartholomew were specified for obtaining surface-water sustainable-yield estimates within the optimization model. Streamflow constraints were specified at two river cells based on average 7-day low flows with 10-year recurrence intervals. Sustainable-yield estimates were affected by the allowable upper limit on withdrawals from wells specified in the optimization model. Withdrawal rates were allowed to increase to 200 percent of the withdrawal rate in 1997. As the overall upper limit is increased, the sustainable yield generally increases. Tests with the optimization model show that without limits on pumping, wells adjacent to sources of water, such as large rivers, would have optimal withdrawal rates that were orders of magnitude larger than rates corresponding to those of 1997. Specifying an upper withdrawal limit of 100 percent of the 1997 withdrawal rate, the sustainable yield from ground water for the entire study area is 70.3 million cubic feet per day, which is about 96 percent of the amount withdrawn in 1997 (73.5 million cubic feet per day). If the upper withdrawal limit is increased to 150 percent of the 1997 withdrawal rate, the sustainable yield from ground water for the entire study area is 80.6 million cubic feet per day, which is about 110 percent of the amount withdrawn in 1997. If the upper withdrawal limit is increased to 200 percent of the 1997 withdrawal rate, the sustainable yield from ground water for the entire study area is 110.2 million cubic feet per day, which is about 150 percent of the amount withdrawn in 1997. Total sustainable yield from the Arkansas River and Bayou Bartholomew is about 4,900 million cubic feet per day, or about 6,700 percent of the amount of ground-water withdrawn in 1997. The large, sustainable yields from surface water represent a potential source of water that could supplement ground water and meet the total water demand. Unmet demand (defined as the difference between the optimized withdrawal rate or sustainable yield, and the anticipated demand) was calculated using different demand rates based on multiples of the 1997-withdrawal rate. Assuming that demand is the 1997 withdrawal rate, and that sustainable-

Study on Warm Forging Prosess of 45 Steel Asymmetric Gear

NASA Astrophysics Data System (ADS)

Qi, Yushi; Du, Zhiming; Sun, Hongsheng; Chen, Lihua; Wang, Changshun

2017-09-01

Asymmetric gear has complex structure, so using plastic forming technology to process the gear has problems of large forming load, short die life, bad tooth filling, and so on. To solve these problems, this paper presents a radial warm extrusion process of asymmetric gear to reduce the forming load and improve the filling in the toothed corner portion. Using the new mold and No. 45 steel to conducting forming experiments under the optimal forming parameters: billet temperature is 800°C, mold temperature is 250°C, the forming speed is 30mm/s, and the friction coefficient is 0.15, we can obtain the complete asymmetric gear with better surface and tooth filling. Asymmetric gears’ microstructure analysis and mechanical testing showed that the small grain evenly distributed in the region near the addendum circle with high strength; the area near the central portion of the gear had a coarse grain size, uneven distribution and low strength. Significant metal flow lines at the corner part of the gear indicated that a large number of late-forming metal flowed into the tooth cavity filling the corner portion.

Rounding corners of nano-square patches for multispectral plasmonic metamaterial absorbers.

PubMed

Ayas, Sencer; Bakan, Gokhan; Dana, Aykutlu

2015-05-04

Multispectral metamaterial absorbers based on metal-insulator-metal nano-square patch resonators are studied here. For a geometry consisting of perfectly nano-square patches and vertical sidewalls, double resonances in the visible regime are observed due to simultaneous excitation of electric and magnetic plasmon modes. Although slightly modifying the sizes of the square patches makes the resonance wavelengths simply shift, rounding corners of the square patches results in emergence of a third resonance due to excitation of the circular cavity modes. Sidewall angle of the patches are also observed to affect the absorption spectra significantly. Peak absorption values for the triple resonance structures are strongly affected as the sidewall angle varies from 90 to 50 degrees. Rounded corners and slanted sidewalls are typical imperfections for lithographically fabricated metamaterial structures. The presented results suggest that imperfections caused during fabrication of the top nano-structures must be taken into account when designing metamaterial absorbers. Furthermore, it is shown that these fabrication imperfections can be exploited for improving resonance properties and bandwidths of metamaterials for various potential applications such as solar energy harvesting, thermal emitters, surface enhanced spectroscopies and photodetection.

Inviscid, nonadiabatic flow fields over blunt, sonic corner bodies for outer planet entry conditions by a method of integral relations

NASA Technical Reports Server (NTRS)

Gnoffo, P. A.

1978-01-01

An investigation has been made into the ability of a method of integral relations to calculate inviscid zero degree angle of attack, radiative heating distributions over blunt, sonic corner bodies for some representative outer planet entry conditions is investigated. Comparisons have been made with a more detailed numerical method, a time asymptotic technique, using the same equilibrium chemistry and radiation transport subroutines. An effort to produce a second order approximation (two-strip) method of integral relations code to aid in this investigation is also described and a modified two-strip routine is presented. Results indicate that the one-strip method of integral relations cannot be used to obtain accurate estimates of the radiative heating distribution because of its inability to resolve thermal gradients near the wall. The two-strip method can sometimes be used to improve these estimates; however, the two-strip method has only a small range of conditions over which it will yield significant improvement over the one-strip method.

Impurity re-distribution in the corner regions of the JET divertor

NASA Astrophysics Data System (ADS)

Widdowson, A.; Coad, J. P.; Alves, E.; Baron-Wiechec, A.; Barradas, N. P.; Catarino, N.; Corregidor, V.; Heinola, K.; Krat, S.; Likonen, J.; Matthews, G. F.; Mayer, M.; Petersson, P.; Rubel, M.; Contributors, JET

2017-12-01

The International Thermonuclear Experimental Reactor (ITER) will use a mixture of deuterium (D) and tritium (T) as the fuel to generate power. Since T is both radioactive and expensive the Joint European Torus (JET) has been at the forefront of research to discover how much T is used and where it may be retained within the main reaction chamber. Until the year 2010 the JET plasma facing components were constructed of carbon fibre composites. During the JET carbon (C) phases impurities accumulated at the corners of the divertor located towards the bottom of the chamber in regions shadowed from the plasma where they are very difficult to reach and remove. This build-up of C and the associated H-isotope (including T) retention were of particular concern for future fusion reactors therefore, in 2010 JET changed the wall protection to (mainly) Be and the divertor to tungsten (W)—the JET ITER-like wall (ILW)—the choice of materials for ITER. This paper reveals that with the JET ILW impurities are still accumulating in the shadowed regions, with Be being the majority element, though the overall quantities are very much reduced from those in the C phases. Material will be transported into the shadowed regions principally when the plasma strike points are on the corner tiles, but particles typically have about a 75% probability of reflection from line-of sight surfaces, and multiple reflection/scattering results in deposition over all surfaces.

Strength Behaviour of Fatigue Cracked Lugs (Festigkeitsverhalten von Rissbehafteten Augenstaeben),

DTIC Science & Technology

1981-01-01

either surface cracks or corner cracks at holes. NASA TN 1)-8244 64 A.F. Grandt Stress intensity factors for some through fracked fastener holes...with Hydropuise L~ngszylinder longitudinal cylinder Druckblversorgung =pressure oil Supply Hydraulikaggregat = hydraulic control unit Fig 7.5 Plan of

One-shot 3D scanning by combining sparse landmarks with dense gradient information

NASA Astrophysics Data System (ADS)

Di Martino, Matías; Flores, Jorge; Ferrari, José A.

2018-06-01

Scene understanding is one of the most challenging and popular problems in the field of robotics and computer vision and the estimation of 3D information is at the core of most of these applications. In order to retrieve the 3D structure of a test surface we propose a single shot approach that combines dense gradient information with sparse absolute measurements. To that end, we designed a colored pattern that codes fine horizontal and vertical fringes, with sparse corners landmarks. By measuring the deformation (bending) of horizontal and vertical fringes, we are able to estimate surface local variations (i.e. its gradient field). Then corner sparse landmarks are detected and matched to infer spare absolute information about the test surface height. Local gradient information is combined with the sparse absolute values which work as anchors to guide the integration process. We show that this can be mathematically done in a very compact and intuitive way by properly defining a Poisson-like partial differential equation. Then we address in detail how the problem can be formulated in a discrete domain and how it can be practically solved by straight forward linear numerical solvers. Finally, validation experiment are presented.

Robot Hand Grips Cylinders Securely

NASA Technical Reports Server (NTRS)

Parma, George F.

1989-01-01

Jaws and linkage accommodate various sizes. Robot hand includes two pairs of parallel jaws that grasp rods, pipes, tubes, struts, and other long, heavy cylindrical objects. Hand features compact rotary drive and butterfly configuration simplifying approach and gripping maneuvers of robot. Parallelogram linkages maintain alignment of each jaw with other jaws. One bar of each linkage connected to one of two concentric, counterrotating shafts; rotation of shafts moves jaws in each pair toward or away from each other to grasp or release workpiece. Each jaw includes rigid gripping pad lined with rubber to give firm grip and to prevent damage to workpiece. Inner cylindrical surface (corner) of each jaw tapers off to flat sides. Enables jaw to grasp workpieces with diameters larger than or equal to twice the corner radius.

Construction, geologic, and hydrologic data for observation wells in the Reelfoot Lake area, Tennessee and Kentucky

USGS Publications Warehouse

Bradley, M.W.

1987-01-01

Twenty-three observation wells were installed at 12 sites in the Reelfoot Lake area of Kentucky and Tennessee during July 1986. The wells were installed to supplement an existing water level network and to provide additional data on the hydraulic characteristics and vertical hydraulic gradients in the alluvial aquifer near Reelfoot Lake. Well yields ranged from less than 20 gallons per minute to about 140 gallons per minute. The specific capacities of the wells ranged from less than 1 to 17.1 gallons per minute per foot of drawdown. Dissolved-solids concentrations ranged from 153 to 475 milligrams per liter at six wells. Three lithological sequences were encountered during drilling. Deep clay and silty clay occurred near the southwest corner of Reelfoot Lake. Predominantly medium- to coarse-grained sand occurred below about 15 feet of silt and clay near the west and northwest sides of the Lake. Along the western limit of the study area, near Lake No. 9 and the Mississippi River, at least about 50 feet of silt and silty sand occurred below land surface. (USGS)

Biomimetic fabrication of materials: the minimalist approach

NASA Astrophysics Data System (ADS)

Lahiri, Joydeep; Xu, Guofeng; Lee, Tu; Dabbs, Daniel M.; Yao, Nan; Aksay, Ilhan A.; Groves, John T.

1996-02-01

The interfacial chemistry between inorganic ceramics and defined organic surfaces is the focus of intense investigation. Partially compressed Langmuir-Blodgett monolayers of anionic porphyrins have been used as modified nucleation sites for calcium carbonate. The porphyrin monolayer has an ordered array of carboxylates, and hence the system serves as a minimalist template for the modeling of complex biogenic acidic glycoproteins for biomineralization. The initial results suggest the formation of calcite with morphologically distinct calcitic rhombs with truncated, 3-edged corners and intricately articulated facial cavities. Stearic acid monolayers yield distinctly different calcite crystals, indicative that the geometrically defined carboxylate array is probably important. Phosphatidylcholine vesicles have been used as a tool for the formation of membrane encapsulated iron-oxides. Gramicindin A ion channels have been embedded in vesicles to kinetically alter the formation and growth of iron oxides, starting with intravesicular ferrous chloride. The results indicate that the presence of ion channels lead to the formation of magnetite vis-a-vis maghemite formation in vesicles lacking the ion channels. The use of ion channels has important implications in probable signal transduction processes during biomineralization pathways.

Space hardware designs, volume 1

NASA Technical Reports Server (NTRS)

Meyer, Rudolf X.; Cribbs, Richard; Honda, Mark; Ma, Christina; Robson, Christopher

1994-01-01

The design of a solar sail space vehicle with a novel sail deployment mechanism is described. The sail is triangular in shape and is deployed and stabilized by three miniature spacecraft, one at each corner of the triangle. A concept demonstrator for a spherical microrover for the exploration of a planetary surface is described. Lastly, laboratory experiments have been conducted to study the migration of thin oil films on metal surfaces in the presence of a thermal gradient.

Evaluation of mechanical properties of some glycine complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagaraju, D.; Raja Shekar, P. V., E-mail: pvrsleo@gmail.com; Chandra, Ch. Sateesh

2014-04-24

The variation of Vickers hardness with load for (101) glycine zinc chloride (GZC), (001) glycine lithium sulphate (GLS), (001) triglycine sulphate (TGS) and (010) glycine phosphite (GPI) crystals was studied. From the cracks initiated along the corners of the indentation impression, crack lengths were measured and the fracture toughness value and brittle index number were determined. The hardness related parameters viz. yield strength and Young’s modulus were also estimated. The anisotropic nature of the crystals was studied using Knoop indentation technique.

Electroosmotic flow mixing in zigzag microchannels.

PubMed

Chen, Jia-Kun; Yang, Ruey-Jen

2007-03-01

In this study we performed numerical and experimental investigations into the mixing of EOFs in zigzag microchannels with two different corner geometries, namely sharp corners and flat corners. In the zigzag microchannel with sharp corners, the flow travels more rapidly near the inner wall of the corner than near the outer wall as a result of the higher electric potential drop. The resulting velocity gradient induces a racetrack effect, which enhances diffusion within the fluid and hence improves the mixing performance. The simulation results reveal that the mixing index is approximately 88.83%. However, the sharp-corner geometry causes residual liquid or bubbles to become trapped in the channel at the point where the flow is almost stationary, when the channel is in the process of cleaning. Accordingly, a zigzag microchannel with flat-corner geometry is developed. The flat-corner geometry forms a convergent-divergent type nozzle which not only enhances the mixing performance in the channel, but also prevents the accumulation of residual liquid or bubbles. Scaling analysis reveals that this corner geometry leads to an effective increase in the mixing length. The experimental results reveal that the mixing index is increased to 94.30% in the flat-corner zigzag channel. Hence, the results demonstrate that the mixing index of the flat-corner zigzag channel is better than that of the conventional sharp-corner microchannel. Finally, the results of Taguchi analysis indicate that the attainable mixing index is determined primarily by the number of corners in the microchannel and by the flow passing height at each corner.

Gaseous Oxidized Mercury Dry Deposition Measurements in Southwestern USA: Comparison between texas, Eastern Oklahoma, and the Four Corners Area

EPA Science Inventory

Gaseous oxidized mercury (GOM) dry deposition measurements using aerodynamic surrogate surface passive samplers were collected in central and eastern Texas and eastern Oklahoma, from September 2011 to September 2012.The purpose of this study was to provide an initial characteriza...

A Secret Support Network

ERIC Educational Resources Information Center

Wasley, Paula

2007-01-01

This article describes Hanover College's Early Alert Team, an early-alert program that seeks to identify students' academic, social, or personal troubles as soon as they surface. The team's five members gather information about students from all corners of the campus and then devise strategies to help them. The early-alert system has not only…

50 CFR 218.4 - Mitigation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... visually searching at night, they shall look a little to one side and out of the corners of their eyes...; surfaced submarines shall have at least one lookout with binoculars. Lookouts already posted for safety of... least two watchstanders are posted, including at least one lookout who has completed required MSAT...

50 CFR 218.4 - Mitigation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... visually searching at night, they shall look a little to one side and out of the corners of their eyes...; surfaced submarines shall have at least one lookout with binoculars. Lookouts already posted for safety of... least two watchstanders are posted, including at least one lookout who has completed required MSAT...

50 CFR 218.13 - Mitigation.

Code of Federal Regulations, 2013 CFR

2013-10-01

... visually searching at night, they shall look a little to one side and out of the corners of their eyes...; surfaced submarines shall have at least one lookout with binoculars. Lookouts already posted for safety of... least one lookout who has completed required MSAT training. (D) Navy vessels shall not knowingly...

50 CFR 218.13 - Mitigation.

Code of Federal Regulations, 2011 CFR

2011-10-01

... visually searching at night, they shall look a little to one side and out of the corners of their eyes...; surfaced submarines shall have at least one lookout with binoculars. Lookouts already posted for safety of... least one lookout who has completed required MSAT training. (D) Navy vessels shall not knowingly...

Experimental Evaluation of Turning Vane Designs for High-speed and Coupled Fan-drive Corners of 0.1-scale Model of NASA Lewis Research Center's Proposed Altitude Wind Tunnel

NASA Technical Reports Server (NTRS)

Gelder, Thomas F.; Moore, Royce D.; Shyne, Rickey J.; Boldman, Donald R.

1987-01-01

Two turning vane designs were experimentally evaluated for the fan-drive corner (corner 2) coupled to an upstream diffuser and the high-speed corner (corner 1) of the 0.1 scale model of NASA Lewis Research Center's proposed Altitude Wind Tunnel. For corner 2 both a controlled-diffusion vane design (vane A4) and a circular-arc vane design (vane B) were studied. The corner 2 total pressure loss coefficient was about 0.12 with either vane design. This was about 25 percent less loss than when corner 2 was tested alone. Although the vane A4 design has the advantage of 20 percent fewer vanes than the vane B design, its vane shape is more complex. The effects of simulated inlet flow distortion on the overall losses for corner 1 or 2 were small.

Autocalibration of multiprojector CAVE-like immersive environments.

PubMed

Sajadi, Behzad; Majumder, Aditi

2012-03-01

In this paper, we present the first method for the geometric autocalibration of multiple projectors on a set of CAVE-like immersive display surfaces including truncated domes and 4 or 5-wall CAVEs (three side walls, floor, and/or ceiling). All such surfaces can be categorized as swept surfaces and multiple projectors can be registered on them using a single uncalibrated camera without using any physical markers on the surface. Our method can also handle nonlinear distortion in the projectors, common in compact setups where a short throw lens is mounted on each projector. Further, when the whole swept surface is not visible from a single camera view, we can register the projectors using multiple pan and tilted views of the same camera. Thus, our method scales well with different size and resolution of the display. Since we recover the 3D shape of the display, we can achieve registration that is correct from any arbitrary viewpoint appropriate for head-tracked single-user virtual reality systems. We can also achieve wallpapered registration, more appropriate for multiuser collaborative explorations. Though much more immersive than common surfaces like planes and cylinders, general swept surfaces are used today only for niche display environments. Even the more popular 4 or 5-wall CAVE is treated as a piecewise planar surface for calibration purposes and hence projectors are not allowed to be overlapped across the corners. Our method opens up the possibility of using such swept surfaces to create more immersive VR systems without compromising the simplicity of having a completely automatic calibration technique. Such calibration allows completely arbitrary positioning of the projectors in a 5-wall CAVE, without respecting the corners.

Surface chemistry of ferrihydrite: Part 1. EXAFS studies of the geometry of coprecipitated and adsorbed arsenate

USGS Publications Warehouse

Waychunas, G.A.; Rea, B.A.; Fuller, C.C.; Davis, J.A.

1993-01-01

EXAFS spectra were collected on both the As and Fe K-edges from samples of two-line ferrihydrite with adsorbed (ADS) and coprecipitated (CPT) arsenate prepared over a range of conditions and arsenate surface coverages. Spectra also were collected for arsenate adsorbed on the surfaces of three FeOOH crystalline polymorphs, ?? (goethite), ?? (akaganeite), and ?? (lepidocrocite), and as a free ion in aqueous: solution. Analyses of the As EXAFS show clear evidence for inner sphere bidentate (bridging) arsenate complexes on the ferrihydrite surface and on the surfaces of the crystalline FeOOH polymorphs. The bridging arsenate is attached to adjacent apices of edge-sharing Fe oxyhydroxyl octahedra. The arsenic-iron distance at the interface (3.28 ??0.01 A ??) is close to that expected for this geometry on the FeOOH polymorph surfaces, but is slightly shorter on the ferrihydrite surfaces (3.25 ?? 0.02 A ??). Mono-dentate arsenate linkages (3.60 ?? 0.03 A ??) also occur on the ferrihydrite, but are not generally observed on the crystalline FeOOH polymorphs. The proportion of monodentate bonds appears largest for adsorption samples with the smallest As Fe molar ratio. In all cases the arsenate tetrahedral complex is relatively undistorted with As-O bonds of 1.66 ?? 0.01 A ??. Precipitation of arsenate or scorodite-like phases was not observed for any samples, all of which were prepared at a pH value of 8. The Fe EXAFS results confirm that the Fe-Fe correlations in the ferrihydrite are progressively disrupted in the CPT samples as the As Fe ratio is increased. Coherent crystallite size is probably no more than 10 A?? in diameter and no Fe oxyhydroxyl octahedra corner-sharing linkages (as would be present in FeOOH polymorphs) are observed at the largest As Fe ratios. Comparison of the number and type of Fe-Fe neighbors with the topological constraints imposed by the arsenate saturation limit in the CPT samples (about 0.7 As Fe) indicates ferrihydrite units consisting mainly of Fe oxyhydroxyl octahedra arranged in short dioctahedral chains with minimal interchain linking by octahedra corners. This is consistent with an enlarged surface area and a larger proportion of sites for bidentate arsenate bonding in CPT samples as compared to the ADS samples, which saturate with arsenate at lower As Fe ratios. The latter samples have larger crystallite sizes and a definite proportion of ferric octahedra sharing corners. The ratio of corner-sharing to edge-sharing Fe oxyhydroxyl octahedra in the ADS samples, and CPT samples with small As loadings, is very similar to what would be present in very small particles of goethite or akaganeite. The difference in the polymeric structure of ADS and CPT samples at higher As Fe ratios is due to strong arsenate bidentate adsorption that poisons the surface of particles of ferrihydrite precipitated in the presence of substantial arsenate, limiting their normal crystallization, and preventing further Fe-O-Fe polymerization. If the arsenate is applied after precipitation much less adsorption occurs since polymerization has already progressed. In both ADS and CPT samples, Fe-O-Fe polymerization increases with age, though at different rates for each type of sample. ?? 1993.

Corner stores: the perspective of urban youth.

PubMed

Sherman, Sandra; Grode, Gabrielle; McCoy, Tara; Vander Veur, Stephanie S; Wojtanowski, Alexis; Sandoval, Brianna Almaguer; Foster, Gary D

2015-02-01

We examined the perspectives of low-income, urban youth about the corner store experience to inform the development of corner store interventions. Focus groups were conducted to understand youth perceptions regarding their early shopping experiences, the process of store selection, reasons for shopping in a corner store, parental guidance about corner stores, and what their ideal, or "dream corner store" would look like. Thematic analysis was employed to identify themes using ATLAS.ti (version 6.1, 2010, ATLAS.ti GmbH) and Excel (version 2010, Microsoft Corp). Focus groups were conducted in nine kindergarten-through-grade 8 (K-8) public schools in low-income neighborhoods with 40 fourth- to sixth-graders with a mean age of 10.9±0.8 years. Youth report going to corner stores with family members at an early age. By second and third grades, a growing number of youth reported shopping unaccompanied by an older sibling or adult. Youth reported that the products sold in stores were the key reason they choose a specific store. A small number of youth said their parents offered guidance on their corner store purchases. When youth were asked what their dream corner store would look like, they mentioned wanting a combination of healthy and less-healthy foods. These data suggest that, among low-income, urban youth, corner store shopping starts at a very young age and that product, price, and location are key factors that affect corner store selection. The data also suggest that few parents offer guidance about corner store purchases, and youth are receptive to having healthier items in corner stores. Corner store intervention efforts should target young children and their parents/caregivers and aim to increase the availability of affordable, healthier products. Copyright © 2015 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

A Wideband Corner-Reflector Antenna for 240 to 400 MHz.

DTIC Science & Technology

1983-09-19

8217 .; ,:,:. .-.:.,.;.. - -... - .- . -.. .-- v...- ..... .-. .-.- 1,.:..- FIGURES 1. Corner Reflector with Open-Sleeve Dipole Feed ............ ...... 7 2...Open-Sleeve Dipole Feed for Corner Reflector, 240-400 MHz........ 8 3. Closeup Photo of Open-Sleeve Dpole ..................... ...... 8 4. VSWR of...4-ft Corner Reflector, Open-Sleeve Dipole Feed .......... 9 5. Gain of Corner Reflector............ .............. . ....... 9 6. Measured E- and H

JOCG Aircraft/Stores Compatibility Symposium Proceedings (8th) Held in Fort Walton Beach, Florida on 23-25 October 1990

DTIC Science & Technology

1990-10-25

Compatibility Sub- Group Steering Committee Sub- Group Chairman Wiley I. Robinson Air Force Systems Command Study Group Chairmen Electrical Interface Joe...on the surface of the body organized into groups defining the corners of a series of four -sided surface panel elements which represent a faceted...Structures Technology. In the Aeroanalysis Group , Dr. Cunningham has conducted many studies leading to devel- opments in the area of analytically

Relevance of impacter shape to nonvisible damage and residual tensile strength of a thick graphite/epoxy laminate

NASA Technical Reports Server (NTRS)

Poe, Clarence C., Jr.

1991-01-01

A study was made to determine the relevance of impacter shape to nonvisible damage and tensile residual strength of a 36 mm thick graphite/epoxy motor case. The shapes of the impacters were as follows: 12.7 mm and 25.4 mm diameter hemispheres, a sharp corner, and a 6.3 mm diameter bolt-like rod. The investigation revealed that damage initiated when the contact pressure exceeded a critical level. However, the damage was not visible on the surface until an even higher pressure was exceeded. The impact energy to initiate damage or cause visible damage on the surface increased approximately with impacter diameter to the third power. The reduction in strength for nonvisible damage increased with increasing diameter, 9 and 30 percent for the 12.7 mm and 25.4 mm diameter hemispheres, respectively. The corner impacter made visible damage on the surface for even the smallest impact energy. The rod impacter acted like a punch and sliced through the composite. Even so, the critical level of pressure to initiate damage was the same for the rod and hemispherical impacters. Factors of safety for nonvisible damage increased with increasing kinetic energy of impact. The effects of impacter shape on impact force, damage size, damage visibility, and residual tensile strength were predicted quite well assuming Hertzian contact and using maximum stress criteria and a surface crack analysis.

Experimental Study of Fillets to Reduce Corner Effects in an Oblique Shock-Wave/Boundary Layer Interaction

NASA Technical Reports Server (NTRS)

Hirt, Stefanie M.

2015-01-01

A test was conducted in the 15 cm x 15 cm supersonic wind tunnel at NASA Glenn Research Center that focused on corner effects of an oblique shock-wave/boundary-layer interaction. In an attempt to control the interaction in the corner region, eight corner fillet configurations were tested. Three parameters were considered for the fillet configurations: the radius, the fillet length, and the taper length from the square corner to the fillet radius. Fillets effectively reduced the boundary-layer thickness in the corner; however, there was an associated penalty in the form of increased boundary-layer thickness at the tunnel centerline. Larger fillet radii caused greater reductions in boundary-layer thickness along the corner bisector. To a lesser, but measureable, extent, shorter fillet lengths resulted in thinner corner boundary layers. Overall, of the configurations tested, the largest radius resulted in the best combination of control in the corner, evidenced by a reduction in boundary-layer thickness, coupled with minimal impacts at the tunnel centerline.

Method for protecting chip corners in wet chemical etching of wafers

DOEpatents

Hui, Wing C.

1994-01-01

The present invention is a corner protection mask design that protects chip corners from undercutting during anisotropic etching of wafers. The corner protection masks abut the chip corner point and extend laterally from segments along one or both corner sides of the corner point, forming lateral extensions. The protection mask then extends from the lateral extensions, parallel to the direction of the corner side of the chip and parallel to scribe lines, thus conserving wafer space. Unmasked bomb regions strategically formed in the protection mask facilitate the break-up of the protection mask during etching. Corner protection masks are useful for chip patterns with deep grooves and either large or small chip mask areas. Auxiliary protection masks form nested concentric frames that etch from the center outward are useful for small chip mask patterns. The protection masks also form self-aligning chip mask areas. The present invention is advantageous for etching wafers with thin film windows, microfine and micromechanical structures, and for forming chip structures more elaborate than presently possible.

Method for protecting chip corners in wet chemical etching of wafers

DOEpatents

Hui, W.C.

1994-02-15

The present invention is a corner protection mask design that protects chip corners from undercutting during anisotropic etching of wafers. The corner protection masks abut the chip corner point and extend laterally from segments along one or both corner sides of the corner point, forming lateral extensions. The protection mask then extends from the lateral extensions, parallel to the direction of the corner side of the chip and parallel to scribe lines, thus conserving wafer space. Unmasked bomb regions strategically formed in the protection mask facilitate the break-up of the protection mask during etching. Corner protection masks are useful for chip patterns with deep grooves and either large or small chip mask areas. Auxiliary protection masks form nested concentric frames that etch from the center outward are useful for small chip mask patterns. The protection masks also form self-aligning chip mask areas. The present invention is advantageous for etching wafers with thin film windows, microfine and micromechanical structures, and for forming chip structures more elaborate than presently possible. 63 figures.

The generation of tire cornering forces in aircraft with a free-swiveling nose gear

NASA Technical Reports Server (NTRS)

Daugherty, R. H.; Stubbs, S. M.

1985-01-01

An experimental investigation was conducted to study the effect of various parameters on the cornering forces produced by a rolling aircraft tire installed on a tilted, free-swiveling nose gear. The parameters studied included tilt angle, trial, tire inflation pressure, rake angle, vertical load, and whether or not a twin tire configuration corotates. These parameters were evaluated by measuring the cornering force produced by an aircraft tire installed on the nose gear of a modified vehicle as it was towed slowly. Cornering force coefficient increased with increasing tilt angle. Increasing trial or rake angle decreased the magnitude of the cornering force coefficient. Tire inflation pressure had no effect on the cornering force coefficient. Increasing vertical load decreased the cornering force coefficient. When the tires of a twin tire system rotated independently, the cornering force coefficients were the same as those for the single-tire configuration. When the twin tire system was made to corotate, however, the cornering force coefficients increased significantly.

A study of the cornering forces generated by aircraft tires on a tilted, free-swiveling nose gear

NASA Technical Reports Server (NTRS)

Daugherty, R. H.; Stubbs, S. M.

1985-01-01

An experimental investigation was conducted to study the effect of various parameters on the cornering forces produced by a rolling aircraft tire installed on a tilted, free-swiveling nose gear. The parameters studied included tilt angle, trial, tire inflation pressure, rake angle, vertical load, and whether or not a twin tire configuration corotates. These parameters were evaluated by measuring the cornering force produced by an aircraft tire installed on the nose gear of a modified vehicle as it was towed slowly. Cornering force coefficient increased with increasing tilt angle. Increasing trial or rake angle decreased the magnitude of the cornering force coefficient. Tire inflation pressure had no effect on the cornering force coefficient. Increasing vertical load decreased the cornering force coefficient. When the tires of a twin tire system rotated independently, the cornering force coefficients were the same as those for the single-tire configuration. When the twin tire system was made to corotate, however, the cornering force coefficients increased significantly.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abercrombie, Robert Knox; Richardson, Gregory David; Scudiere, Matthew Bligh

A pad is disclosed for use in a weighing system for weighing a load. The pad includes a weighing platform, load cells, and foot members. Improvements to the pad reduce or substantially eliminate rotation of one or more of the corner foot members. A flexible foot strap disposed between the corner foot members reduces rotation of the respective foot members about vertical axes through the corner foot members and couples the corner foot members such that rotation of one corner foot member results in substantially the same amount of rotation of the other corner foot member. In a strapless variantmore » one or more fasteners prevents substantially all rotation of a foot member. In a diagonal variant, a foot strap extends between a corner foot member and the weighing platform to reduce rotation of the foot member about a vertical axis through the corner foot member.« less

ARC-1979-AC79-7081

NASA Image and Video Library

1979-07-08

P-21747 C Range: 2,200,000 miles This image shows a region of the Jovian atmosphere from approximately 25° N to the equatorial region. The north temperate jet, at approximately 23° N, where the wind speed is about 150 meters per second, is seen as a dark brown line from the left-hand edge to the right-hand corner of the picture. The wispy clouds of the north equatorial belt appear as shades of brown. The lower right-hand corner of the image shows the brighter (white) clouds of the equatorial region. A small blue area is apparent near the lower edge, which corresponds to a region free of the upper clouds, where it is possible to penetrate to cloud layers approximately 60 kilometers below the visible surface.

ARC-1979-A79-7081

NASA Image and Video Library

1979-07-08

P-21747 BW Range: 2,200,000 miles This image shows a region of the Jovian atmosphere from approximately 25° N to the equatorial region. The north temperate jet, at approximately 23° N, where the wind speed is about 150 meters per second, is seen as a dark brown line from the left-hand edge to the right-hand corner of the picture. The wispy clouds of the north equatorial belt appear as shades of brown. The lower right-hand corner of the image shows the brighter (white) clouds of the equatorial region. A small blue area is apparent near the lower edge, which corresponds to a region free of the upper clouds, where it is possible to penetrate to cloud layers approximately 60 kilometers below the visible surface.

Stabilization of Landslides for the Improvement of Aquatic Habitat

Treesearch

Michael J. Furniss

1989-01-01

Chronic surface and mass erosion from recent landslides often prevents the recovery of productive stream habitats following initial mass failure events. Low-cost methods that can accelerate recovery and stabilization processes have been employed on numerous failed slopes in the Six Rivers National Forest in the northwest corner of California, with notable success. Two...

Gregg T. Beckham | NREL

Science.gov Websites

Molecular Dynamics, and a suite of free energy methods such as MD Umbrella Sampling, Equilibrium Path chain on the crystal surface, and the degree of crystallinity in the substrate. We have used free energy shows the free energy results for edge, middle, and corner chains for all four types of cellulose. All

Borescope Device Takes Impressions In Ducts

NASA Technical Reports Server (NTRS)

Walter, Richard F.; Turner, Laura J.

1990-01-01

Maneuverable device built around borescope equipped to make impression molds of welded joints in interior surfaces of ducts. Molds then examined to determine degress of mismatch in welds. Inserted in duct, and color-coded handles on ends of cables used to articulate head to maneuver around corners. Use of device fairly easy and requires little training.

System for loading slab-gel holders for electrophoresis separation

DOEpatents

Anderson, Norman G.; Anderson, Norman L.

1979-01-01

A slab-gel loading system includes a prismatic chamber for filling a plurality of slab-gel holders simultaneously. Each slab-gel holder comprises a pair of spaced apart plates defining an intermediate volume for gel containment. The holders are vertically positioned in the chamber with their major surfaces parallel to the chamber end walls. A liquid inlet is provided at the corner between the bottom and a side wall of the chamber for distributing a polymerizable monomer solution or a coagulable colloidal solution into each of the holders. The chamber is rotatably supported so that filling can begin with the corner having the liquid inlet directed downwardly such that the solution is gently funneled upwardly, without mixing, along the diverging side and bottom surfaces. As filling proceeds, the chamber is gradually rotated to position the bottom wall in a horizontal mode. The liquid filling means includes a plastic envelope with a septum dividing it into two compartments for intermixing two solutions of different density and thereby providing a liquid flow having a density gradient. The resulting gels have a density gradient between opposite edges for subsequent use in electrophoresis separations.

Exhumation at orogenic indentor corners under long-term glacial conditions: Example of the St. Elias orogen, Southern Alaska

NASA Astrophysics Data System (ADS)

Spotila, James A.; Berger, Aaron L.

2010-07-01

Syntaxial bends in convergent plate boundaries, or indentor corners, display some of the most intriguing deformation patterns on Earth and are type localities for "aneurysms" of coupled erosion, thermal weakening, and strain. The St. Elias orogen in Alaska is a small, young convergent system that has been dominated by a glacial climate for much of its history and exhibits two prominent indentor corners that are not well understood. We have added 40 new apatite (U-Th)/He ages to the already extensive dataset for the low-temperature cooling history of this orogen to constrain the pattern of exhumation in these indentor corners. Ages from the western syntaxis show minor variation across the structural hinge, suggesting that the bend has little effect on the pattern of exhumation and that structures, including the Bagley fault, connect smoothly from the orogen core to the subduction zone to the southwest. Rock uplift on the north flank of the range appears to increase steadily towards the eastern syntaxis, which represents the apex in the right-angle bend between a transform fault in the south and the collision zone in the west. Based on age-elevation relationships, zones of relative rock uplift can be defined in which the Mt. Logan massif, or the area just north of the eastern syntaxis, experienced ˜ 4.8 km greater rock uplift than background levels northwest of the western syntaxis. A bulge in relative rock uplift is symmetric about the hinge in the eastern indentor corner. However, rates of denudation in this bulge are not as rapid as the core of the fold and thrust belt and are lower than those implied by detrital cooling ages from beneath the Seward Glacier. This implies that a large bull's eye of ultra-rapid (˜ 5 mm/yr) exhumation does not occur and that the subpopulation of young detrital ages may be sourced from a narrow transpressional zone along the Fairweather fault. Unlike the Himalayan syntaxes, it thus appears that an aneurysm of coupled erosion-strain has not developed in either indentor corner of the St. Elias orogen. This may indicate a limit to the degree to which glacial erosion can partition strain in convergent orogens. Similarly, the likely existence of a through-going dextral fault, the Totschunda fault, through the eastern syntaxis implies that tectonics, rather than surface processes, exerts the main control on strain partitioning in these corners.

Line spring model and its applications to part-through crack problems in plates and shells

NASA Technical Reports Server (NTRS)

Erdogan, Fazil; Aksel, Bulent

1988-01-01

The line spring model is described and extended to cover the problem of interaction of multiple internal and surface cracks in plates and shells. The shape functions for various related crack geometries obtained from the plane strain solution and the results of some multiple crack problems are presented. The problems considered include coplanar surface cracks on the same or opposite sides of a plate, nonsymmetrically located coplanar internal elliptic cracks, and in a very limited way the surface and corner cracks in a plate of finite width and a surface crack in a cylindrical shell with fixed end.

Line Spring Model and Its Applications to Part-Through Crack Problems in Plates and Shells

NASA Technical Reports Server (NTRS)

Erdogan, F.; Aksel, B.

1986-01-01

The line spring model is described and extended to cover the problem of interaction of multiple internal and surface cracks in plates and shells. The shape functions for various related crack geometries obtained from the plane strain solution and the results of some multiple crack problems are presented. The problems considered include coplanar surface cracks on the same or opposite sides of a plate, nonsymmetrically located coplanar internal elliptic cracks, and in a very limited way the surface and corner cracks in a plate of finite width and a surface crack in a cylindrical shell with fixed end.

Experimental Modeling of Dynamic Shallow Dip-Slip Faulting

NASA Astrophysics Data System (ADS)

Uenishi, K.

2010-12-01

In our earlier study (AGU 2005, SSJ 2005, JPGU 2006), using a finite difference technique, we have conducted some numerical simulations related to the source dynamics of shallow dip-slip earthquakes, and suggested the possibility of the existence of corner waves, i.e., shear waves that carry concentrated kinematic energy and generate extremely strong particle motions on the hanging wall of a nonvertical fault. In the numerical models, a dip-slip fault is located in a two-dimensional, monolithic linear elastic half space, and the fault plane dips either vertically or 45 degrees. We have investigated the seismic wave field radiated by crack-like rupture of this straight fault. If the fault rupture, initiated at depth, arrests just below or reaches the free surface, four Rayleigh-type pulses are generated: two propagating along the free surface into the opposite directions to the far field, the other two moving back along the ruptured fault surface (interface) downwards into depth. These downward interface pulses may largely control the stopping phase of the dynamic rupture, and in the case the fault plane is inclined, on the hanging wall the interface pulse and the outward-moving Rayleigh surface pulse interact with each other and the corner wave is induced. On the footwall, the ground motion is dominated simply by the weaker Rayleigh pulse propagating along the free surface because of much smaller interaction between this Rayleigh and the interface pulse. The generation of the downward interface pulses and corner wave may play a crucial role in understanding the effects of the geometrical asymmetry on the strong motion induced by shallow dip-slip faulting, but it has not been well recognized so far, partly because those waves are not expected for a fault that is located and ruptures only at depth. However, the seismological recordings of the 1999 Chi-Chi, Taiwan, the 2004 Niigata-ken Chuetsu, Japan, earthquakes as well as a more recent one in Iwate-Miyagi Inland, Japan in 2008, for example, seem to support the need for careful mechanical consideration. In this contribution, utilizing two-dimensional dynamic photoelasticity in conjunction with high speed digital cinematography, we try to perform "fully controlled" laboratory experiments of dip-slip faulting and observe the propagation of interface pulses and corner waves mentioned above. A birefringent material containing a (model) dip-slip fault plane is prepared, and rupture is initiated in that material using an Nd:YAG laser system, and the evolution of time-dependent isochromatic fringe patterns (contours of maximum in-plane shear stress) associated with the dynamic process of shallow dip-slip faulting is recorded. Use of Nd:YAG laser pulses, instead of ignition of explosives, for rupture initiation may enhance the safety of laboratory fracture experiments and enable us to evaluate the energy entering the material (and hence the energy balance in the system) more precisely, possibly in a more controlled way.

Guiding, bending, and splitting of coupled defect surface modes in a surface-wave photonic crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Zhen; Gao, Fei; Zhang, Baile, E-mail: blzhang@ntu.edu.sg

2016-01-25

We experimentally demonstrate a type of waveguiding mechanism for coupled surface-wave defect modes in a surface-wave photonic crystal. Unlike conventional spoof surface plasmon waveguides, waveguiding of coupled surface-wave defect modes is achieved through weak coupling between tightly localized defect cavities in an otherwise gapped surface-wave photonic crystal, as a classical wave analogue of tight-binding electronic wavefunctions in solid state lattices. Wave patterns associated with the high transmission of coupled defect surface modes are directly mapped with a near-field microwave scanning probe for various structures including a straight waveguide, a sharp corner, and a T-shaped splitter. These results may find usemore » in the design of integrated surface-wave devices with suppressed crosstalk.« less

Preliminary Geological Map of the Ac-H-7 Kerwan Quadrangle of Ceres: An Integrated Mapping Study Using Dawn Spacecraft Data

NASA Astrophysics Data System (ADS)

Williams, D. A.; Crown, D. A.; Mest, S. C.; Buczkowski, D.; Schenk, P.; Scully, J. E. C.; Jaumann, R.; Roatsch, T.; Preusker, F.; Platz, T.; Nathues, A.; Hoffmann, M.; Schäfer, M.; Marchi, S.; De Sanctis, M. C.; Russell, C. T.; Raymond, C. A.

2015-12-01

We used geologic mapping applied to Dawn spacecraft data as a tool to understand the geologic history of the Ac-H-7 Kerwan Quadrangle of dwarf planet Ceres. This region, located between 22˚S-22˚N and 72-144˚E, hosts four primary features: 1) the northern part of the 284 km diameter impact basin Kerwan in the center and SE corner of the quadrangle, whose rim is degraded and whose interior has been filled with a 'smooth material' that hosts a significantly lower impact crater density than most of the rest of Ceres' surface; 2) a portion of the 125 km diameter crater Dantu, whose ejecta field covers the NE corner of the quadrangle and where color data show both bright and dark materials, suggesting excavation of terrains of different compositions; 3) an unnamed double crater in the NW corner of the quadrangle surrounded by an ejecta field; and 4) a heavily cratered plains unit in the SW corner of the quadrangle that appears to be part of the dominant unit across Ceres surface. Key goals of the ongoing mapping are to assess the types of processes that might be responsible for resurfacing by the smooth unit, and understanding the nature of the variably-colored Dantu ejecta. The Dantu region is one of two longitudinally distinct regions on Ceres where ESA Hershel space telescope data suggested a release of water vapor (1). At the time of this writing geologic mapping was performed on Framing Camera (FC) mosaics from the Approach (1.3 km/px) and Survey (415 m/px) orbits, including grayscale and color images and digital terrain models derived from stereo images. In Fall 2015 images from the High Altitude Mapping Orbit (140 m/px) will be used to refine the mapping, followed by Low Altitude Mapping Orbit (35 m/px) images in January 2016. Support of the Dawn Instrument, Operations, and Science Teams is acknowledged. This work is supported by grants from NASA, and from the German and Italian Space Agencies. Reference: (1) Küppers, M., et al. (2014). Nature, v. 505, 525-527.

Analysis of Curved Target-Type Thrust Reversers

DTIC Science & Technology

1974-06-07

methods f-or two -dimensional cases, the Levi - Civita method provides a \\ariet> t>l bucket shapes and enables one to round off the sharp corners of...surface In the present work three methods arc employed to investigate the deflection of mviscid. incompressible curved surfaces: Levi - Civitas ...shapes are shown in Fig. V A special case for (T, =0 31416 and fr2= 0.47124, and A = 0. ,*46, (/< = 6X ), is shown in Fig 4. Fvidently, Levi - Civita "s

Crystalline embryos at ice-vapor interfaces

NASA Technical Reports Server (NTRS)

Bartley, D. L.

1976-01-01

The nucleation of small monolayer ice-like clusters at the basal and prism ice-vapor interfaces is considered. It is found that the basal surfaces prefer triangular embryos with an orientation that reverses from layer to layer, whereas the most stable clusters on the prism surfaces are rectangular in configuration. At any given saturation ratio, the preferred prism clusters are found to have a critical energy of formation significantly lower than that of the basal clusters, basically because of differences in cluster corner free energies.

Universal corner entanglement of Dirac fermions and gapless bosons from the continuum to the lattice

NASA Astrophysics Data System (ADS)

Helmes, Johannes; Hayward Sierens, Lauren E.; Chandran, Anushya; Witczak-Krempa, William; Melko, Roger G.

2016-09-01

A quantum critical (QC) fluid exhibits universal subleading corrections to the area law of its entanglement entropies. In two dimensions, when the partition involves a corner of angle θ , the subleading term is logarithmic with coefficient aα(θ ) for the α -Rényi entropy. In the smooth limit θ →π ,a1(θ ) yields the central charge of the stress tensor when the QC point is described by a conformal field theory (CFT). For general Rényi indices and angles, aα(θ ) is richer and few general results exist. We study aα(θ ) focusing on two benchmark CFTs, the free Dirac fermion and boson. We perform numerical lattice calculations to obtain high precision results in θ ,α regimes hitherto unexplored. We derive field theory estimates for aα(θ ) , including exact results, and demonstrate an excellent quantitative match with our numerical calculations. We also develop and test strong lower bounds, which apply to both free and interacting QC systems. Finally, we comment on the near collapse of aα(θ ) for various theories, including interacting O (N ) models.

Formative evaluation for a healthy corner store initiative in Pitt County, North Carolina: engaging stakeholders for a healthy corner store initiative, part 2.

PubMed

Pitts, Stephanie B Jilcott; Bringolf, Karamie R; Lloyd, Cameron L; McGuirt, Jared T; Lawton, Katherine K; Morgan, Jo

2013-07-18

We examined the feasibility of increasing access to healthful food in corner stores to inform a Communities Putting Prevention to Work (CPPW) initiative by engaging stakeholders (corner store owners and customers) in a formative evaluation. Qualitative interviews were conducted with corner store owners and managers (n = 11). Customer intercept surveys (n = 179) were also conducted with customers of 9 stores. Corner stores were located in rural food deserts (municipalities without a chain supermarket) and in low-income, urban municipalities in eastern North Carolina. Interviews were transcribed verbatim and double-coded. Qualitative themes related to feasibility of increasing access to healthful foods were extracted. Shopping patterns of rural and urban customers were compared by using t tests. Corner store owners were willing to stock more healthful foods, but they perceived that customer demand for these foods was low. Rural customers reported more frequently shopping at corner stores than urban customers and more frequently stated that the reason they do not eat more fruits and vegetables is that the stores in which they shop do not sell them. Most customers reported they would be very or somewhat likely to purchase fresh produce at a corner store. Corner stores may be an important source of food for rural and low-income residents and thus a good place in which to intervene. The results of this formative evaluation were used to plan and evaluate a CPPW healthy corner store initiative.

Hydrogeologic and water-quality characteristics of the Red River-Winnipeg aquifer northwestern Minnesota

USGS Publications Warehouse

Ruhl, J.F.; Adolphson, D.G.

1986-01-01

Ground water generally flows eastward through the aquifer from North Dakota and discharges upward to wells and to overlying deposits. Yields of wells open to the full thickness of the aquifer range from 100 t 250 gallons per minute. The water is unsuitable for most uses because of the high mineral content. Dissolved-solids concentrations range from about 3,000 milligrams per liter in the eastern part of the aquifer to about 60,000 milligrams per liter in the northwestern corner of Minnesota.

Personality and Strategy: How the Personalities of General MacArthur and Admiral King Shaped Allied Strategy in the Pacific in World War Two

DTIC Science & Technology

2002-05-31

one corner of New Mexico to another.9 While it is unlikely that a four - year -old kept pace at the head of the column for very...final year . Not surprisingly Reminiscences contains no mention of the incident above. In fact his memoirs spend only three brief pages on the four years ...dominant personalities 4 of two men primarily directing the course of the war, yields a highly illuminating case study in the influence of

Reducing the burden of diarrhea among children under five years old: lessons learned from oral rehydration therapy corner program implementation in Northern Nigeria.

PubMed

Charyeva, Zulfiya; Cannon, Molly; Oguntunde, Olugbenga; Garba, Aminu Magashi; Sambisa, William; Bassi, Amos Paul; Ibrahim, Mohammed Auwal; Danladi, Saba'atu Elizabeth; Lawal, Nurudeen

2015-05-01

In Nigeria, diarrhea remains one of the leading causes of death among children under five years old. Oral Rehydration Therapy (ORT) corners were introduced to health facilities in Bauchi and Sokoto states to serve as points of treatment for sick children and equip caregivers with necessary skills in case management of diarrhea and diarrhea prevention. The operations research study examined the effect of facility-based ORT corners on caregivers' knowledge and skills in management of simple and moderate diarrhea at home, as well as caregivers' and service providers' perceived facilitators and barriers to utilization and delivering of ORT corner services. It also examined whether ORT activities were conducted according to the established protocols. This quantitative study relied on multiple sources of information to provide a complete picture of the current status of ORT corner services, namely surveys with ORT corner providers (N = 21), health facility providers (N = 23) and caregivers (N = 229), as well as a review of service statistics and health facility observations. Frequency distribution and binary analysis were conducted. The study revealed that ORT corner users were more knowledgeable in diarrhea prevention and management and demonstrated better skills for managing diarrhea at home than ORT corner non-users. However, the percentage of knowledgeable ORT users is not optimal, and providers need to continue to work toward improving such knowledge. ORT corner providers identified a lack of supplies as the major barrier for providing services. Furthermore, the study revealed a lack of information, education and communication materials, supportive supervision, and protocols and guidelines for delivering ORT corner services, as well as inadequate documentation of services provided at ORT corners. Recommendations for ORT corners program planners and implementers include ensuring all ORT corners have oral rehydration salt (ORS) packages and salt, sugar, and zinc tablets in stock, a secured commodity supply chain to avoid stockouts, and adequate policies and procedures in place.

Balanced Can

ERIC Educational Resources Information Center

Shakerin, Said

2013-01-01

The ordinary 12-oz beverage cans in the figures below are not held up with any props or glue. The bottom of such cans is stepped at its circumference for better stacking. When this kind of can is tilted, as shown in Fig. 1, the outside corners of the step touch the surface beneath, providing an effective contact about 1 cm wide. Because the…

30 CFR 7.67 - Construction test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... § 7.66. (a) Test procedures. (1) The blasting unit shall be dropped 20 times from a height of 3 feet... each time in an attempt to have a different surface, corner, or edge strike the floor first for each... shall be submerged in 1 foot of water for 1 hour in each of 3 tests. The water temperature shall be...

Corner Store Inventories, Purchases, and Strategies for Intervention: A Review of the Literature.

PubMed

Langellier, Brent A; Garza, Jeremiah R; Prelip, Michael L; Glik, Deborah; Brookmeyer, Ron; Ortega, Alexander N

2013-01-01

An increasingly popular strategy to improving the food retail environment and promoting healthy eating in low-income and minority communities is the corner store conversion. This approach involves partnering with small 'corner' food stores to expand access to high-quality fruits, vegetables, and other healthy foods. We conducted a structured review of the literature to assess inventories and sales in corner stores, as well as to identify intervention strategies employed by corner store conversions. Our review returned eight descriptive studies that discussed corner store inventories and sales, as well as ten intervention studies discussing six unique corner store conversion interventions in the United States, the Marshall Islands, and Canada. Common intervention strategies included: 1) partnering with an existing store, 2) stocking healthy foods, and 3) social marketing and nutrition education. We summarize each strategy and review the effectiveness of overall corner store conversions at changing peoples' food purchasing, preparation, and consumption behaviors. Consumption of fresh, healthy, affordable foods could be improved by supporting existing retailers to expand their selection of healthy foods and promoting healthy eating at the neighborhood level. Additional corner store conversions should be conducted to determine the effectiveness and importance of specific intervention strategies.

49 CFR 231.29 - Road locomotives with corner stairways.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must be... 49 Transportation 4 2011-10-01 2011-10-01 false Road locomotives with corner stairways. 231.29...

49 CFR 231.29 - Road locomotives with corner stairways.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must be... 49 Transportation 4 2010-10-01 2010-10-01 false Road locomotives with corner stairways. 231.29...

Metal dusting behavior of 321 stainless steel: Effects of edge and corner

NASA Astrophysics Data System (ADS)

Chang, Chia-Hao; Tsai, Wen-Ta

2011-04-01

The metal dusting behavior of 321 stainless steel (SS) in a flowing mixed CO/H2/H2O gas stream at 600 °C for 500 h and 1000 h was investigated. The microstructures and chemical compositions of the reaction products at the surface and those in the substrate under the pits were examined by using a scanning electron microscope (SEM) and a transmission electron microscope (TEM), each combined with an energy dispersive spectrometer (EDS). The phenomenon of a pitting attack that occurred preferentially at the edges and corners of the specimens was the focus of this study. The carburization behavior in the steel substrate under the pits was also characterized. Matrix carbide in the form of Cr7C3 and grain boundary carbide in the form of Cr23C6 were identified by TEM.

Assessment of the effects of air pollution on european monuments through a geochemical characterization of black crusts

NASA Astrophysics Data System (ADS)

Comite, Valeria; Barca, Donatella; Belfiore, Cristina Maria; Bonazza, Alessandra; La Russa, Mauro Francesco; Ruffolo, SIlvestro Antonio; Pezzino, Antonino; Sabbioni, Cristina

2014-05-01

This contribution focuses on spectrometric analyses carried out on black crust samples, collected from buildings and churches belonging to the European built Heritage, i.e., the Corner Palace in Venice (Italy), the Cathedral of St. Rombouts in Mechelen (Belgium), the Church of St. Eustache in Paris (France) and the Tower of London (United Kingdom). Such monuments, all built in carbonate stones, were selected for their historic and artistic relevance, as well as for their location in different urban environments. For an exhaustive account of the sampled black crusts, an approach integrating complementary techniques was used, including OM, SEM-EDS, FT-IR and LA-ICP-MS. The complete characterization of the damage layers provided information on their chemical composition, the state of conservation of the underlying substrates and the interactions between crusts and stones. In particular, the geochemical study in terms of trace elements revealed that all crusts are enriched in heavy metals (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Sn, Ti, V, and Zn) compared to substrates. The different concentrations of such elements in all analyzed crust samples can be ascribed to several factors, such as: height of sampling, morphology of the sampled surfaces (vertical or horizontal), exposure to atmospheric agents as well as to direct (road or boat traffic) or indirect (industries) sources of pollution, accumulation time of pollutants on the surface, wash out and particulate air pollution. Specifically, the crusts collected at lower heights (Corner Palace, Cathedral of St. Rombouts, Tower of London) resulted to be mainly influenced by mobile sources of pollution (vehicular or boat traffic), while samples taken at higher heights (Church of St. Eustache and Corner Palace) are generally mostly affected by stationary combustion sources. In some cases, the detailed analysis of multilayered crusts (Palazzo Corner) contributed to recognize the variation of combustion sources responsible for the deterioration of surfaces over time. In addition, the possibility of analyzing altered portions of the substrate (Tower of London) permitted to observe that some elements (Zn, Cu and Ni) show concentrations similar and, sometimes, higher than the overlying crusts. This result can be explained by the geochemical mobility of such elements (at specific environmental conditions), which accelerate the process of sulfating, rapidly promoting the formation of new layers of crust. In conclusion, the study of black crusts and altered substrates in terms of trace elements may provide information useful to understand the influence of the pollutants in the genesis of such degradation forms.

Microfabricated discontinuous-edge surface topographies influence osteoblast adhesion, migration, cytoskeletal organization, and proliferation and enhance matrix and mineral deposition in vitro.

PubMed

Hamilton, D W; Wong, K S; Brunette, D M

2006-05-01

The fabrication of surfaces that stimulate increased adhesion, migration, and differentiated function of osteoblasts has been viewed as being desirable for many orthopedic applications. Previous studies have shown that microfabricated pits and grooves alter adhesion, spreading, matrix secretion, and production of mineral by rat calvarial osteoblasts (RCOs). The mechanisms underlying these effects are unknown, although microenvironment and cell alignment are considered to play a role. The aim of this work was to investigate the behavior of RCOs on microfabricated discontinuous-edge surfaces (DESs), which could provide an alternative means to control both the microenvironment and cellular alignment. Two types of discontinuous-type structures were employed, gap-cornered boxes and micron scale pillars. DES gap-cornered boxes and the pillars influenced the arrangement of F-actin, microtubules, and vinculin. Osteoblasts were guided in their direction of migration on both types of substrata. Both box DESs and pillars altered the staining intensity and localization pattern of phosphotyrosine and src-activated FAK localization. Cell multilayering, matrix deposition, and mineralization were enhanced on both discontinuous topographies when compared with smooth controls. This study shows that DESs alter adhesion, migration, and proliferative responses from osteoblasts at early time points (<1 week) and promote multilayering, matrix deposition, and mineral deposition at later times (2-6 weeks). Such topographical patterns could potentially be employed as effective surface features on bone-contacting implants or in membrane-based periodontal applications.

Identifying Financially Sustainable Pricing Interventions to Promote Healthier Beverage Purchases in Small Neighborhood Stores.

PubMed

Nau, Claudia; Kumanyika, Shiriki; Gittelsohn, Joel; Adam, Atif; Wong, Michelle S; Mui, Yeeli; Lee, Bruce Y

2018-01-25

Residents of low-income communities often purchase sugar-sweetened beverages (SSBs) at small, neighborhood "corner" stores. Lowering water prices and increasing SSB prices are potentially complementary public health strategies to promote more healthful beverage purchasing patterns in these stores. Sustainability, however, depends on financial feasibility. Because in-store pricing experiments are complex and require retailers to take business risks, we used a simulation approach to identify profitable pricing combinations for corner stores. The analytic approach was based on inventory models, which are suitable for modeling business operations. We used discrete-event simulation to build inventory models that use data representing beverage inventory, wholesale costs, changes in retail prices, and consumer demand for 2 corner stores in Baltimore, Maryland. Model outputs yielded ranges for water and SSB prices that increased water demand without loss of profit from combined water and SSB sales. A 20% SSB price increase allowed lowering water prices by up to 20% while maintaining profit and increased water demand by 9% and 14%, for stores selling SSBs in 12-oz cans and 16- to 20-oz bottles, respectively. Without changing water prices, profits could increase by 4% and 6%, respectively. Sensitivity analysis showed that stores with a higher volume of SSB sales could reduce water prices the most without loss of profit. Various combinations of SSB and water prices could encourage water consumption while maintaining or increasing store owners' profits. This model is a first step in designing and implementing profitable pricing strategies in collaboration with store owners.

Quantitative analysis of surface characteristics and morphology in Death Valley, California using AIRSAR data

NASA Technical Reports Server (NTRS)

Kierein-Young, K. S.; Kruse, F. A.; Lefkoff, A. B.

1992-01-01

The Jet Propulsion Laboratory Airborne Synthetic Aperture Radar (JPL-AIRSAR) is used to collect full polarimetric measurements at P-, L-, and C-bands. These data are analyzed using the radar analysis and visualization environment (RAVEN). The AIRSAR data are calibrated using in-scene corner reflectors to allow for quantitative analysis of the radar backscatter. RAVEN is used to extract surface characteristics. Inversion models are used to calculate quantitative surface roughness values and fractal dimensions. These values are used to generate synthetic surface plots that represent the small-scale surface structure of areas in Death Valley. These procedures are applied to a playa, smooth salt-pan, and alluvial fan surfaces in Death Valley. Field measurements of surface roughness are used to verify the accuracy.

Relevance of impacter shape to nonvisible damage and residual tensile strength of a thick graphite/epoxy laminate

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1990-01-01

A study was made to determine the relevance of impacter shape to nonvisible damage and tensile residual strength of a 36 mm (1.4 in.) thick graphite/epoxy motor case. The shapes of the impacters were as follows: 12.7 mm (0.5 in.) and 25.4 mm (1.0 in.) diameter hemispheres, a sharp corner, and a 6.3 mm (0.25 in.) diameter bolt-like rod. The investigation revealed that damage initiated when the contact pressure exceeded a critical level. However, the damage was not visible on the surface until an even higher pressure was exceeded. The damage on the surface consisted of a crater shaped like the impacter, and the damage below the surface consisted of broken fibers. The impact energy to initiate damage or cause visible damage on the surface increased approximately with impacter diameter to the third power. The reduction in strength for nonvisible damage increased with increasing diameter, 9 and 30 percent for the 12.7 mm (0.5 in.) and 25.4 mm (1.0 in.) diameter hemispheres, respectively. The corner impacter made visible damage on the surface for even the smallest impact energy. The rod impacter acted like a punch and sliced through the composite. Even so, the critical level of pressure to initiate damage was the same for the rod and hemispherical impacters. Factors of safety for nonvisible damage increased with increasing kinetic energy of impact. The effects of impacter shape on impact force, damage size, damage visibility, and residual tensile strength were predicted quite well assuming Hertzian contact and using maximum stress criteria and a surface crack analysis.

Conjunctive-use optimization model of the Mississippi River Valley alluvial aquifer of northeastern Arkansas

USGS Publications Warehouse

Czarnecki, John B.; Clark, Brian R.; Reed, Thomas B.

2003-01-01

The Mississippi River Valley alluvial aquifer is a water-bearing assemblage of gravels and sands that underlies about 32,000 square miles of Missouri, Kentucky, Tennessee, Mississippi, Louisiana, and Arkansas. Because of the heavy demands placed on the aquifer, several large cones of depression over 100 feet deep have formed in the potentiometric surface, resulting in lower well yields and degraded water quality in some areas. A ground-water flow model of the alluvial aquifer was previously developed for an area covering 14,104 square miles, extending northeast from the Arkansas River into the northeast corner of Arkansas and parts of southeastern Missouri. The flow model showed that continued ground-water withdrawals at rates commensurate with those of 1997 could not be sustained indefinitely without causing water levels to decline below half the original saturated thickness of the aquifer. To develop estimates of withdrawal rates that could be sustained in compliance with the constraints of critical ground-water area designation, conjunctive-use optimization modeling was applied to the flow model of the alluvial aquifer in northeastern Arkansas. Ground-water withdrawal rates form the basis for estimates of sustainable yield from the alluvial aquifer and from rivers specified within the alluvial aquifer model. A management problem was formulated as one of maximizing the sustainable yield from all ground-water and surface-water withdrawal cells within limits imposed by plausible withdrawal rates, and within specified constraints involving hydraulic head and streamflow. Steady-state flow conditions were selected because the maximized withdrawals are intended to represent sustainable yield of the system (a rate that can be maintained indefinitely). Within the optimization model, 11 rivers are specified. Surface-water diversion rates that occurred in 2000 were subtracted from specified overland flow at the appropriate river cells. Included in these diversions were the planned diversions of 63,339,248 ft3/d for the Bayou Meto project area and 55,078,367 ft3/d for the Grand Prairie project area, which factor in an additional 30 and 40 percent transmission loss, respectively. Streamflow constraints were specified at all 1,165 river cells based on average 7-day minimum flows for 10 years. Sustainable yield for all rivers ranged from 0 (Current, Little Red, and Bayou Meto Rivers) to almost 5 billion cubic feet per day for the Arkansas River. Total sustainable yield from all rivers combined was 12.8 billion cubic feet per day, which represents a substantial source for supplementing ground water to meet the total water demand. Sustainable-yield estimates are affected by the allowable upper limit on withdrawals from wells specified in the optimization model. Ground-water withdrawal rates were allowed to vary as much as 200 percent of the withdrawal rate in 1997. As the overall upper limit on withdrawals is increased, the sustainable yield generally increases. Tests with the optimization model show that without limits on pumping, wells adjacent to sources of water would have optimized withdrawal rates that were orders of magnitude larger than rates corresponding to those of 1997. The sustainable yield from ground water for the entire study area while setting the maximum upper limit as the amount withdrawn in 1997 is 360 million cubic feet per day, which is only about 57 percent of the amount withdrawn in 1997 (635.6 million cubic feet per day). Optimal sustainable yields from within the Bayou Meto irrigation project area and within the Grand Prairie irrigation project area are 18.1 and 9.1 million cubic feet per day, respectively, assuming a maximum allowable withdrawal rate equal to 1997 rates. These values of sustainable yield represent 35 and 30 percent respectively of the amount pumped from these project areas in 1997. Unmet demand (defined as the difference between the optimized withdrawal rate or sustainable yield, a

Laplacian scale-space behavior of planar curve corners.

PubMed

Zhang, Xiaohong; Qu, Ying; Yang, Dan; Wang, Hongxing; Kymer, Jeff

2015-11-01

Scale-space behavior of corners is important for developing an efficient corner detection algorithm. In this paper, we analyze the scale-space behavior with the Laplacian of Gaussian (LoG) operator on a planar curve which constructs Laplacian Scale Space (LSS). The analytical expression of a Laplacian Scale-Space map (LSS map) is obtained, demonstrating the Laplacian Scale-Space behavior of the planar curve corners, based on a newly defined unified corner model. With this formula, some Laplacian Scale-Space behavior is summarized. Although LSS demonstrates some similarities to Curvature Scale Space (CSS), there are still some differences. First, no new extreme points are generated in the LSS. Second, the behavior of different cases of a corner model is consistent and simple. This makes it easy to trace the corner in a scale space. At last, the behavior of LSS is verified in an experiment on a digital curve.

7 CFR 905.16 - Regulation Area II.

Code of Federal Regulations, 2011 CFR

2011-01-01

... counties to the Southwest corner of Section 23, Township 14 South, Range 31 East; thence continue South to the Southwest corner of Section 35, Township 14 South, Range 31 East; thence East to the Northwest corner of Township 15 South, Range 32 East; thence South to the Southwest corner of Township 17 South...

Vertical Corner Feature Based Precise Vehicle Localization Using 3D LIDAR in Urban Area

PubMed Central

Im, Jun-Hyuck; Im, Sung-Hyuck; Jee, Gyu-In

2016-01-01

Tall buildings are concentrated in urban areas. The outer walls of buildings are vertically erected to the ground and almost flat. Therefore, the vertical corners that meet the vertical planes are present everywhere in urban areas. These corners act as convenient landmarks, which can be extracted by using the light detection and ranging (LIDAR) sensor. A vertical corner feature based precise vehicle localization method is proposed in this paper and implemented using 3D LIDAR (Velodyne HDL-32E). The vehicle motion is predicted by accumulating the pose increment output from the iterative closest point (ICP) algorithm based on the geometric relations between the scan data of the 3D LIDAR. The vertical corner is extracted using the proposed corner extraction method. The vehicle position is then corrected by matching the prebuilt corner map with the extracted corner. The experiment was carried out in the Gangnam area of Seoul, South Korea. In the experimental results, the maximum horizontal position error is about 0.46 m and the 2D Root Mean Square (RMS) horizontal error is about 0.138 m. PMID:27517936

Detonation corner turning in vapor-deposited explosives using the micromushroom test

NASA Astrophysics Data System (ADS)

Tappan, Alexander S.; Yarrington, Cole D.; Knepper, Robert

2017-06-01

Detonation corner turning describes the ability of a detonation wave to propagate into unreacted explosive that is not immediately in the path normal to the wave. The classic example of corner turning is cylindrical and involves a small diameter explosive propagating into a larger diameter explosive as described by Los Alamos' Mushroom test (e.g. (Hill, Seitz et al. 1998)), where corner turning is inferred from optical breakout of the detonation wave. We present a complimentary method to study corner turning in millimeter-scale explosives through the use of vapor deposition to prepare the slab (quasi-2D) analog of the axisymmetric mushroom test. Because the samples are in a slab configuration, optical access to the explosive is excellent and direct imaging of the detonation wave and ``dead zone'' that results during corner turning is possible. Results are compared for explosives that demonstrate a range of behaviors, from pentaerythritol tetranitrate (PETN), which has corner turning properties that are nearly ideal; to HNAB (hexanitroazobenzene), which has corner turning properties that reveal a substantial dead zone. Results are discussed in the context of microstructure and detonation failure thickness.

Feasibility of increasing access to healthy foods in neighborhood corner stores.

PubMed

O'Malley, Keelia; Gustat, Jeanette; Rice, Janet; Johnson, Carolyn C

2013-08-01

The feasibility of working with neighborhood corner stores to increase the availability of fresh fruit and vegetables in low-income neighborhoods in New Orleans was assessed. Household interviews and 24-hour dietary recalls (n = 97), corner store customer intercept interviews (n = 60) and interviews with corner store operators (owners/managers) (n = 12) were conducted in three neighborhoods without supermarkets. Regional produce wholesalers were contacted by phone. Results indicated that the majority of neighborhood residents use supermarkets or super stores as their primary food source. Those who did shop at corner stores typically purchased prepared foods and/or beverages making up nearly one third of their daily energy intake. Most individuals would be likely to purchase fresh fruit and vegetables from the corner stores if these foods were offered. Store operators identified cost, infrastructure and lack of customer demand as major barriers to stocking more fresh produce. Produce wholesalers did not see much business opportunity in supplying fresh produce to neighborhood corner stores on a small scale. Increasing availability of fresh fruit and vegetables in corner stores may be more feasible with the addition of systems changes that provide incentives and make it easier for neighborhood corner stores to stock and sell fresh produce.

Brain medical image diagnosis based on corners with importance-values.

PubMed

Gao, Linlin; Pan, Haiwei; Li, Qing; Xie, Xiaoqin; Zhang, Zhiqiang; Han, Jinming; Zhai, Xiao

2017-11-21

Brain disorders are one of the top causes of human death. Generally, neurologists analyze brain medical images for diagnosis. In the image analysis field, corners are one of the most important features, which makes corner detection and matching studies essential. However, existing corner detection studies do not consider the domain information of brain. This leads to many useless corners and the loss of significant information. Regarding corner matching, the uncertainty and structure of brain are not employed in existing methods. Moreover, most corner matching studies are used for 3D image registration. They are inapplicable for 2D brain image diagnosis because of the different mechanisms. To address these problems, we propose a novel corner-based brain medical image classification method. Specifically, we automatically extract multilayer texture images (MTIs) which embody diagnostic information from neurologists. Moreover, we present a corner matching method utilizing the uncertainty and structure of brain medical images and a bipartite graph model. Finally, we propose a similarity calculation method for diagnosis. Brain CT and MRI image sets are utilized to evaluate the proposed method. First, classifiers are trained in N-fold cross-validation analysis to produce the best θ and K. Then independent brain image sets are tested to evaluate the classifiers. Moreover, the classifiers are also compared with advanced brain image classification studies. For the brain CT image set, the proposed classifier outperforms the comparison methods by at least 8% on accuracy and 2.4% on F1-score. Regarding the brain MRI image set, the proposed classifier is superior to the comparison methods by more than 7.3% on accuracy and 4.9% on F1-score. Results also demonstrate that the proposed method is robust to different intensity ranges of brain medical image. In this study, we develop a robust corner-based brain medical image classifier. Specifically, we propose a corner detection method utilizing the diagnostic information from neurologists and a corner matching method based on the uncertainty and structure of brain medical images. Additionally, we present a similarity calculation method for brain image classification. Experimental results on two brain image sets show the proposed corner-based brain medical image classifier outperforms the state-of-the-art studies.

New vibration-assisted magnetic abrasive polishing (VAMAP) method for microstructured surface finishing.

PubMed

Guo, Jiang; Kum, Chun Wai; Au, Ka Hing; Tan, Zhi'En Eddie; Wu, Hu; Liu, Kui

2016-06-13

In order to polish microstructured surface without deteriorating its profile, we propose a new vibration-assisted magnetic abrasive polishing (VAMAP) method. In this method, magnetic force guarantees that the magnetic abrasives can well contact the microstructured surface and access the corners of microstructures while vibration produces a relative movement between microstructures and magnetic abrasives. As the vibration direction is parallel to the microstructures, the profile of the microstructures will not be deteriorated. The relation between vibration and magnetic force was analyzed and the feasibility of this method was experimentally verified. The results show that after polishing, the surface finish around microstructures was significantly improved while the profile of microstructures was well maintained.

Forest conditions in the Black Mesa Forest Reserve, Arizona

USGS Publications Warehouse

Plummer, F.G.; Rixon, T.F.; Dodwell, Arthur

1904-01-01

The Black Mesa Forest Reserve, in Arizona, was created by proclamation of President McKinley dated August 17, 1898. The following are its boundaries; "Beginning at a point on the boundary line between Arizona and New Mexico where it is intersected by the north line of township seven (7) north, range thirty-one (31) east, Gila and Salt River meridian, Arizona; thence westerly along the township line to the southeast corner of township eight (8) north, range twenty-seven (27) east; thence northerly to the northeast corner of said township; thence westerly along the second (2nd) standard parallel north to the southeast corner of township nine (9) north, range twenty-six (26) east; thence northerly to the northeast corner of said township; thence westerly along the township line to the southeast corner of township ten (10) north, range twenty-two (22) east; thence northerly to the northeast corner of said township; thence westerly along the township line to the southeast corner of township eleven (11) north, range nineteen (19) east; thence northerly.along the range line to its point of intersection with the forty miles limit of the grant to the Atlantic and Pacific Railroad Company; thence westerly following the forty miles limit of said grant to its intersection with the range line between ranges five (5) and six (6) east, in township fifteen (15) north; thence southerly to the southwest corner of said township; thence easterly along the township line to the northwest corner of township fourteen (14) north, range seven (7) east; thence southerly along the range line to the southwest corner of township thirteen (13) north, range seven (7) east; thence easterly along the third (3rd) standard parallel north to the northwest corner of township twelve (12) north, range eight (8) east; thence southerly to the south- west corner of said township; thence easterly along the township line to the north- west corner of township eleven (11) north, range twelve (12) east; thence southerly to the southwest corner of said township; thence easterly to the northwest corner of the White Mountain Indian Reservation; thence in a general easterly, southeasterly, and southerly direction along the northern and eastern boundaries of said reservation to its intersection with the Gila and Salt River base line; thence easterly along said base line to its intersection with the boundary line between Arizona and New Mexico; thence northerly along said boundary line to the point where it intersects the north line of township seven (7) north, range thirty-one (31) east, the place of beginning." 

Gaseous oxidized mercury dry deposition measurements in the southwestern USA: a comparison between Texas, eastern Oklahoma, and the Four Corners area.

PubMed

Sather, Mark E; Mukerjee, Shaibal; Allen, Kara L; Smith, Luther; Mathew, Johnson; Jackson, Clarence; Callison, Ryan; Scrapper, Larry; Hathcoat, April; Adam, Jacque; Keese, Danielle; Ketcher, Philip; Brunette, Robert; Karlstrom, Jason; Van der Jagt, Gerard

2014-01-01

Gaseous oxidized mercury (GOM) dry deposition measurements using aerodynamic surrogate surface passive samplers were collected in central and eastern Texas and eastern Oklahoma, from September 2011 to September 2012. The purpose of this study was to provide an initial characterization of the magnitude and spatial extent of ambient GOM dry deposition in central and eastern Texas for a 12-month period which contained statistically average annual results for precipitation totals, temperature, and wind speed. The research objective was to investigate GOM dry deposition in areas of Texas impacted by emissions from coal-fired utility boilers and compare it with GOM dry deposition measurements previously observed in eastern Oklahoma and the Four Corners area. Annual GOM dry deposition rate estimates were relatively low in Texas, ranging from 0.1 to 0.3 ng/m(2)h at the four Texas monitoring sites, similar to the 0.2 ng/m(2)h annual GOM dry deposition rate estimate recorded at the eastern Oklahoma monitoring site. The Texas and eastern Oklahoma annual GOM dry deposition rate estimates were at least four times lower than the highest annual GOM dry deposition rate estimate previously measured in the more arid bordering western states of New Mexico and Colorado in the Four Corners area.

[Arthrodesis of the shoulder. A new and soft-tissue-sparing technique with a deep locking plate in the supraspinatus fossa].

PubMed

Klonz, A; Habermeyer, P

2007-10-01

Arthrodesis of the glenohumeral joint is a difficult intervention that involves a relatively high probability of complications. A stable internal fixation and secure consolidation is required. The operation needs to achieve several conditions: thorough denudation of the cartilage and partial decortication of the subchondral bone; good congruence of the corresponding surfaces; compression of the gap by tension screws and lasting stability. For increased primary stability a neutralizing plate is generally used as well as a compression screw. Up to now, the plate has usually been applied starting from the scapular spine and extending across the acromial corner to the humeral shaft. A wide exposure is needed for this procedure; the plate is difficult to shape during the operation and often causes some discomfort because it protrudes at the acromial corner. We present an alternative position of the plate in the supraspinatus fossa, where we have sited a 4.5 mm LCP locking plate (Synthes). The implant is inserted under the acromion, does not cause any discomfort at the acromial corner, and is far easier to shape. When it is used in association with a transarticular compressive screw, the technique results in a very stable situation, which allows physiotherapy from the first day after surgery onward.

A quantized microwave quadrupole insulator with topologically protected corner states

NASA Astrophysics Data System (ADS)

Peterson, Christopher W.; Benalcazar, Wladimir A.; Hughes, Taylor L.; Bahl, Gaurav

2018-03-01

The theory of electric polarization in crystals defines the dipole moment of an insulator in terms of a Berry phase (geometric phase) associated with its electronic ground state. This concept not only solves the long-standing puzzle of how to calculate dipole moments in crystals, but also explains topological band structures in insulators and superconductors, including the quantum anomalous Hall insulator and the quantum spin Hall insulator, as well as quantized adiabatic pumping processes. A recent theoretical study has extended the Berry phase framework to also account for higher electric multipole moments, revealing the existence of higher-order topological phases that have not previously been observed. Here we demonstrate experimentally a member of this predicted class of materials—a quantized quadrupole topological insulator—produced using a gigahertz-frequency reconfigurable microwave circuit. We confirm the non-trivial topological phase using spectroscopic measurements and by identifying corner states that result from the bulk topology. In addition, we test the critical prediction that these corner states are protected by the topology of the bulk, and are not due to surface artefacts, by deforming the edges of the crystal lattice from the topological to the trivial regime. Our results provide conclusive evidence of a unique form of robustness against disorder and deformation, which is characteristic of higher-order topological insulators.

Reduced-Dimensionality Semiclassical Transition State Theory: Application to Hydrogen Atom Abstraction and Exchange Reactions of Hydrocarbons.

PubMed

Greene, Samuel M; Shan, Xiao; Clary, David C

2015-12-17

Quantum mechanical methods for calculating rate constants are often intractable for reactions involving many atoms. Semiclassical transition state theory (SCTST) offers computational advantages over these methods but nonetheless scales exponentially with the number of degrees of freedom (DOFs) of the system. Here we present a method with more favorable scaling, reduced-dimensionality SCTST (RD SCTST), that treats only a subset of DOFs of the system explicitly. We apply it to three H abstraction and exchange reactions for which two-dimensional potential energy surfaces (PESs) have previously been constructed and evaluated using RD quantum scattering calculations. We differentiated these PESs to calculate harmonic frequencies and anharmonic constants, which were then used to calculate cumulative reaction probabilities and rate constants by RD SCTST. This method yielded rate constants in good agreement with quantum scattering results. Notably, it performed well for a heavy-light-heavy reaction, even though it does not explicitly account for corner-cutting effects. Recent extensions to SCTST that improve its treatment of deep tunneling were also evaluated within the reduced-dimensionality framework. The success of RD SCTST in this study suggests its potential applicability to larger systems.

Air Monitoring Network at Tonopah Test Range: Network Description, Capabilities, and Analytical Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartwell, William T.; Daniels, Jeffrey; Nikolich, George

2012-01-01

During the period April to June 2008, at the behest of the Department of Energy (DOE), National Nuclear Security Administration, Nevada Site Office (NNSA/NSO); the Desert Research Institute (DRI) constructed and deployed two portable environmental monitoring stations at the Tonopah Test Range (TTR) as part of the Environmental Restoration Project Soils Activity. DRI has operated these stations since that time. A third station was deployed in the period May to September 2011. The TTR is located within the northwest corner of the Nevada Test and Training Range (NTTR), and covers an area of approximately 725.20 km2 (280 mi2). The primarymore » objective of the monitoring stations is to evaluate whether and under what conditions there is wind transport of radiological contaminants from Soils Corrective Action Units (CAUs) associated with Operation Roller Coaster on TTR. Operation Roller Coaster was a series of tests, conducted in 1963, designed to examine the stability and dispersal of plutonium in storage and transportation accidents. These tests did not result in any nuclear explosive yield. However, the tests did result in the dispersal of plutonium and contamination of surface soils in the surrounding area.« less

Energy band gaps in graphene nanoribbons with corners

NASA Astrophysics Data System (ADS)

Szczȩśniak, Dominik; Durajski, Artur P.; Khater, Antoine; Ghader, Doried

2016-05-01

In the present paper, we study the relation between the band gap size and the corner-corner length in representative chevron-shaped graphene nanoribbons (CGNRs) with 120° and 150° corner edges. The direct physical insight into the electronic properties of CGNRs is provided within the tight-binding model with phenomenological edge parameters, developed against recent first-principle results. We show that the analyzed CGNRs exhibit inverse relation between their band gaps and corner-corner lengths, and that they do not present a metal-insulator transition when the chemical edge modifications are introduced. Our results also suggest that the band gap width for the CGNRs is predominantly governed by the armchair edge effects, and is tunable through edge modifications with foreign atoms dressing.

From clusters to bulk: A relativistic density functional investigation on a series of gold clusters Aun, n=6,…,147

NASA Astrophysics Data System (ADS)

Häberlen, Oliver D.; Chung, Sai-Cheong; Stener, Mauro; Rösch, Notker

1997-03-01

A series of gold clusters spanning the size range from Au6 through Au147 (with diameters from 0.7 to 1.7 nm) in icosahedral, octahedral, and cuboctahedral structure has been theoretically investigated by means of a scalar relativistic all-electron density functional method. One of the main objectives of this work was to analyze the convergence of cluster properties toward the corresponding bulk metal values and to compare the results obtained for the local density approximation (LDA) to those for a generalized gradient approximation (GGA) to the exchange-correlation functional. The average gold-gold distance in the clusters increases with their nuclearity and correlates essentially linearly with the average coordination number in the clusters. An extrapolation to the bulk coordination of 12 yields a gold-gold distance of 289 pm in LDA, very close to the experimental bulk value of 288 pm, while the extrapolated GGA gold-gold distance is 297 pm. The cluster cohesive energy varies linearly with the inverse of the calculated cluster radius, indicating that the surface-to-volume ratio is the primary determinant of the convergence of this quantity toward bulk. The extrapolated LDA binding energy per atom, 4.7 eV, overestimates the experimental bulk value of 3.8 eV, while the GGA value, 3.2 eV, underestimates the experiment by almost the same amount. The calculated ionization potentials and electron affinities of the clusters may be related to the metallic droplet model, although deviations due to the electronic shell structure are noticeable. The GGA extrapolation to bulk values yields 4.8 and 4.9 eV for the ionization potential and the electron affinity, respectively, remarkably close to the experimental polycrystalline work function of bulk gold, 5.1 eV. Gold 4f core level binding energies were calculated for sites with bulk coordination and for different surface sites. The core level shifts for the surface sites are all positive and distinguish among the corner, edge, and face-centered sites; sites in the first subsurface layer show still small positive shifts.

49 CFR 178.609 - Test requirements for packagings for infectious substances.

Code of Federal Regulations, 2011 CFR

2011-10-01

... free-fall drops onto a rigid, nonresilient, flat, horizontal surface from a height of 9 m (30 feet... must be dropped, one in each of the following orientation: (i) Flat on the base; (ii) Flat on the top; (iii) Flat on the longest side; (iv) Flat on the shortest side; and (v) On a corner. (2) Where the...

49 CFR 173.175 - Permeation devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., flat and horizontal surface from a height of 1.8 m (5.9 feet): (i) One drop flat on the bottom; (ii) One drop flat on the top; (iii) One drop flat on the long side; (iv) One drop flat on the short side; (v) One drop on a corner at the junction of three intersecting edges; and (2) A force applied to the...

49 CFR 173.175 - Permeation devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., flat and horizontal surface from a height of 1.8 m (5.9 feet): (i) One drop flat on the bottom; (ii) One drop flat on the top; (iii) One drop flat on the long side; (iv) One drop flat on the short side; (v) One drop on a corner at the junction of three intersecting edges; and (2) A force applied to the...

Envirenmental Baseline Survey, Manch Manor Housing Area, Nellis Air Force Base, Nevada

DTIC Science & Technology

2003-12-01

within the Manch Manor Housing Area three times within the last 5 years. 3.2.1.3 Surface Drainage. Nellis AFB is in the Colorado River Drainage Basin...PAVING CORNER DURANGO AND CHEYENNE SHWS TC736310.3s Page 3 of 7 ORPHAN SUMMARY Clly EDRIO Si!eName Site Address Zip Dalabase{s) Facility JD LAS VEGAS

Negative refractive index, perfect lenses and checkerboards: Trapping and imaging effects in folded optical spaces

NASA Astrophysics Data System (ADS)

Guenneau, Sébastien; Ramakrishna, S. Anantha

2009-06-01

Newly discovered metamaterials have opened new vistas for better control of light via negative refraction, whereby light refracts in the "wrong" manner. These are dielectric and metallic composite materials structured at subwavelength lengthscales. Their building blocks consist of local resonators such as conducting thin bars and split rings driving the material parameters such as the dielectric permittivity and magnetic permeability to negative (complex) values. Combined together, these structural elements can bring about a (complex valued) negative effective refractive index for the Snell-Descartes law and result in negative refraction of radiation. Negative refractive index materials can support a host of surface plasmon states for both polarizations of light. This makes possible unique effects such as imaging with subwavelength image resolution through the Pendry-Veselago slab lens. Other geometries have also been investigated, such as cylindrical or spherical lenses that enable a magnification of images with subwavelength resolution. Superlenses of three-fold (equilateral triangle), four-fold (square) and six-fold (hexagonal) geometry allow for multiple images, respectively two, three, and five. Generalization to rectangular and triangular checkerboards consisting of alternating cells of positive and negative refractive index represents a very singular situation in which the density of modes diverges at the corners, with an infinity of images. Sine-cosecant anisotropic heterogeneous square and triangular checkerboards can be respectively mapped onto three-dimensional cubic and icosahedral corner lenses consisting of alternating positive and negative refractive regions. All such systems with corners between negative and positive refractive media display very singular behavior with the local density of states becoming infinitely large at the corner, in the limit of no dissipation. We investigate all of these, using the unifying viewpoint of transformation optics. To cite this article: S. Guenneau, S.A. Ramakrishna, C. R. Physique 10 (2009).

Enhanced visible light photocatalytic activity in N-doped edge- and corner-truncated octahedral Cu2O

NASA Astrophysics Data System (ADS)

Zou, Mingming; Liu, Honghong; Feng, Lu; Thomas, Tiju; Yang, Minghui

2017-03-01

Edge- and corner-truncated octahedral Cu2O is successfully synthesized using an aqueous mixture of CuCl2, sodium dodecyl sulfate, NaOH, and NH2OH3·HCl. Cu2O1-xNx(150 °C, 30 min) samples are synthesized by nitridation of Cu2O using an ammonothermal process. Cu retains a formal valence state through and beyond the nitridation process. N concentration in this sample is 1.73 at%, out of which 1.08 at% is substitutional in nature. Photocatalytic activity of Cu2O1-xNx(150 °C, 30 min) sample is investigated and compared to that of pristine edge- and corner-truncated octahedral Cu2O. Results show that Cu2O1-xNx(150 °C, 30 min) sample with dominant {110} facets has a higher photocatalytic activity than the pristine Cu2O material. Higher surface energy and a greater density of the ;Cu; dangling bonds on {110} facets of edge- and corner-truncated octahedral Cu2O1-xNx is the plausible reason for the observed optimum catalytic activity. Furthermore defect states induced by nitridation results in improved visible light adsorption. And also the band edge states changes which brought about by N doping. This is an interesting result since it bypasses the usual challenge faced by pristine Cu2O which have band edge states between which transitions are normally forbidden. Selective radical quenching experiments suggest that photocatalytic activity of Cu2O1-xNx is due to formation of hydroxyl radicals in water, subsequent to photogeneration of charge carriers in the photocatalyst.

Aircraft radial-belted tire evaluation

NASA Technical Reports Server (NTRS)

Yager, Thomas J.; Stubbs, Sandy M.; Davis, Pamela A.

1990-01-01

An overview is given of the ongoing joint NASA/FAA/Industry Surface Traction And Radial Tire (START) Program being conducted at NASA Langley's Aircraft Landing Dynamics Facility (ALDF). The START Program involves tests using three different tire sizes to evaluate tire rolling resistance, braking, and cornering performance throughout the aircraft ground operational speed range for both dry and wet runway surfaces. Preliminary results from recent 40 x 14 size bias-ply, radial-belted, and H-type aircraft tire tests are discussed. The paper concludes with a summary of the current program status and planned ALDF test schedule.

EM-ANIMATE: A Computer Program for Displaying and Animating Electromagnetic Near-Field and Surface-Current Solutions: Video Supplement to NASA Technical Memorandum 4539

NASA Technical Reports Server (NTRS)

Hom, Kam W.

1994-01-01

In this video, several examples of electromagnetic field and surface-current animation sequences are shown to demonstrate the visualization capabilities of the EM-ANIMATE computer program. These examples show the animation of total and scattered electric near fields from test bodies of a flat plate, a corner reflector, and a sphere. These test cases show the electric-field behavior caused by different scattering mechanisms through the animation of electromagnetic data from the EM-ANIMATE routine.

Recognising and responding to 'cutting corners' when providing nursing care: a qualitative study.

PubMed

Jones, Angela; Johnstone, Megan-Jane; Duke, Maxine

2016-08-01

The aim of this study is to report on a key finding of a larger study investigating the 'gaps' in patient care that registered nurses encounter during the course of their practice. A key finding of this larger study was that 'cutting corners' was a gap discerned by nurses. 'Cutting corners' has been characterised as a 'violation' and threat to patient safety, although there is a paucity of research on this issue. Naturalistic inquiry using a qualitative exploratory descriptive approach. Data were collected from a purposeful sample of 71 registered nurses from emergency department, critical care, perioperative, rehabilitation and transitional care and neurosciences settings in Australia and analysed using content and thematic analysis strategies. Cutting corners was a common practice that encompassed (1) the partial or complete omission of patient care, (2) delays in providing care and (3) the failure to do things correctly. Corners were cut in patient assessment, essential nursing care, the care of central venous catheters and medication administration. The practice of cutting corners was perceived as contributing to preventable adverse events. The study found that cutting corners created gaps that contributed to unfinished nursing care and preventable adverse events. The findings of the study raise the possibility that cutting corners is a salient but underinvestigated characteristic of nursing practice. Further research and inquiry are needed to deepen understanding of cutting corners and its impact on patient safety. Identifying the nature and implications of cutting corners when providing nursing care is an important contributing factor to improving patient safety and quality care. © 2016 John Wiley & Sons Ltd.

A physical optics/equivalent currents model for the RCS of trihedral corner reflectors

NASA Technical Reports Server (NTRS)

Balanis, Constantine A.; Polycarpou, Anastasis C.

1993-01-01

The scattering in the interior regions of both square and triangular trihedral corner reflectors is examined. The theoretical model presented combines geometrical and physical optics (GO and PO), used to account for reflection terms, with equivalent edge currents (EEC), used to account for first-order diffractions from the edges. First-order, second-order, and third-order reflection terms are included. Calculating the first-order reflection terms involves integrating over the entire surface of the illuminated plate. Calculating the second- and third-order reflection terms, however, is much more difficult because the illuminated area is an arbitrary polygon whose shape is dependent upon the incident angles. The method for determining the area of integration is detailed. Extensive comparisons between the high-frequency model, Finite-Difference Time-Domain (FDTD) and experimental data are used for validation of the radar cross section (RCS) of both square and triangular trihedral reflectors.

Raman scattering enhanced within the plasmonic gap between an isolated Ag triangular nanoplate and Ag film

NASA Astrophysics Data System (ADS)

Li, Kuanguo; Jiang, Kang; Zhang, Lan; Wang, Yong; Mao, Lei; Zeng, Jie; Lu, Yonghua; Wang, Pei

2016-04-01

Enhanced electromagnetic field in the tiny gaps between metallic nanostructures holds great promise in optical applications. Herein, we report novel out-of-plane nanogaps composed of micrometer-sized Ag triangular nanoplates (AgTN) on Ag films. Notably, the new coupled plasmonic structure can dramatically enhance the surface-enhanced Raman scattering (SERS) by visible laser excitation, although the micrometer-sized AgTN has localized plasmon resonance at infrared wavelength. This enhancement is derived from the gap plasmon polariton between the AgTN and Ag film, which is excited via the antenna effect of the corner and edge of the AgTN. Systematic SERS studies indicated that the plasmon enhancement was on the order of corner > edge > face. These results were further verified by theoretical simulations. Our device paves the way for rational design of sensitive SERS substrates by judiciously choosing appropriate nanoparticles and optimizing the gap distance.

S/Ka Dichroic Plate with Rounded Corners for NASA's 34-m Beam-Waveguide Antenna

NASA Astrophysics Data System (ADS)

Veruttipong, W.; Khayatian, B.; Imbriale, W.

2016-02-01

An S-/Ka-band frequency selective surface (FSS) or a dichroic plate is designed, manufactured, and tested for use in NASA's Deep Space Network (DSN) 34-m beam-waveguide (BWG) antennas. Due to its large size, the proposed dichroic incorporates a new design feature: waveguides with rounded corners to cut cost and allow ease of manufacturing the plate. The dichroic is designed using an analysis that combines the finite-element method (FEM) for arbitrarily shaped guides with the method of moments and Floquet mode theory for periodic structures. The software was verified by comparison with previously measured and computed dichroic plates. The large plate was manufactured with end-mill machining. The RF performance was measured and is in excellent agreement with the analytical results. The dichroic has been successfully installed and is operational at DSS-24, DSS-34, and DSS-54.

Numerical simulation of aerothermal loads in hypersonic engine inlets due to shock impingement

NASA Technical Reports Server (NTRS)

Ramakrishnan, R.

1992-01-01

The effect of shock impingement on an axial corner simulating the inlet of a hypersonic vehicle engine is modeled using a finite-difference procedure. A three-dimensional dynamic grid adaptation procedure is utilized to move the grids to regions with strong flow gradients. The adaptation procedure uses a grid relocation stencil that is valid at both the interior and boundary points of the finite-difference grid. A linear combination of spatial derivatives of specific flow variables, calculated with finite-element interpolation functions, are used as adaptation measures. This computational procedure is used to study laminar and turbulent Mach 6 flows in the axial corner. The description of flow physics and qualitative measures of heat transfer distributions on cowl and strut surfaces obtained from the analysis are compared with experimental observations. Conclusions are drawn regarding the capability of the numerical scheme for enhanced modeling of high-speed compressible flows.

Numerical simulation of supersonic gap flow.

PubMed

Jing, Xu; Haiming, Huang; Guo, Huang; Song, Mo

2015-01-01

Various gaps in the surface of the supersonic aircraft have a significant effect on airflows. In order to predict the effects of attack angle, Mach number and width-to-depth ratio of gap on the local aerodynamic heating environment of supersonic flow, two-dimensional compressible Navier-Stokes equations are solved by the finite volume method, where convective flux of space term adopts the Roe format, and discretization of time term is achieved by 5-step Runge-Kutta algorithm. The numerical results reveal that the heat flux ratio is U-shaped distribution on the gap wall and maximum at the windward corner of the gap. The heat flux ratio decreases as the gap depth and Mach number increase, however, it increases as the attack angle increases. In addition, it is important to find that chamfer in the windward corner can effectively reduce gap effect coefficient. The study will be helpful for the design of the thermal protection system in reentry vehicles.

Investigation of Corner Effect and Identification of Tunneling Regimes in L-Shaped Tunnel Field-Effect-Transistor.

PubMed

Najam, Faraz; Yu, Yun Seop

2018-09-01

Corner-effect existing in L-shaped tunnel field-effect-transistor (LTFET) was investigated using numerical simulations and band diagram analysis. It was found that the corner-effect is caused by the convergence of electric field in the sharp source corner present in an LTFET, thereby increasing the electric field in the sharp source corner region. It was found that in the corner-effect region tunneling starts early, as a function of applied bias, as compared to the rest of the channel not affected by corner-effect. Further, different tunneling regimes as a function of applied bias were identified in the LTFET including source to channel and channel to channel tunneling regimes. Presence of different tunneling regimes in LTFET was analytically justified with a set of equations developed to model source to channel, and channel to channel tunneling currents. Drain-current-gate-voltage (Ids-Vgs) characteristics obtained from the equations is in reasonable qualitative agreement with numerical simulation.

Single-stage evaluation of highly-loaded high-Mach-number compressor stages 5. Data and performance of baseline, corner-blow wall suction and combined corner blow wall suction stator

NASA Technical Reports Server (NTRS)

Nikkanen, J. P.; Brooky, J. P.

1972-01-01

A single-stage compressor with a rotor tip speed of 1600 ft/sec and a 0.5 hub tip ratio was used to investigate the effects of several stator endwall treatment methods on stage range and performance. These endwall treatment methods consisted of stator corner-blow, annular wall suction upstream of stator leading edge, and combined corner-blow and annular wall suction. The overall stage performance with corner blow was essentially the same as the baseline performance. The performance for the annular wall suction and the combined corner-blow and wall suction showed a reduction in peak efficiency of 2.5 percentage points compared to the baseline data.

4-corner arthrodesis and proximal row carpectomy: a biomechanical comparison of wrist motion and tendon forces.

PubMed

Debottis, Daniel P; Werner, Frederick W; Sutton, Levi G; Harley, Brian J

2013-05-01

Controversy exists as to whether a proximal row carpectomy (PRC) is a better procedure than scaphoid excision with 4-corner arthrodesis for preserving motion in the painful posttraumatic arthritic wrist. The purpose of this study was to determine how the kinematics and tendon forces of the wrist are altered after PRC and 4-corner arthrodesis. We tested 6 fresh cadaver forearms for the extremes of wrist motion and then used a wrist simulator to move them through 4 cyclic dynamic wrist motions, during which time we continuously recorded the tendon forces. We repeated the extremes of wrist motion measurements and the dynamic motions after scaphoid excision with 4-corner arthrodesis, and then again after PRC. We analyzed extremes of wrist motion and the peak tendon forces required for each dynamic motion using a repeated measures analysis of variance. Wrist extremes of motion significantly decreased after both the PRC and 4-corner arthrodesis compared with the intact wrist. Wrist flexion decreased on average 13° after 4-corner arthrodesis and 12° after PRC. Extension decreased 20° after 4-corner arthrodesis and 12° after PRC. Four-corner arthrodesis significantly decreased wrist ulnar deviation from the intact wrist. Four-corner arthrodesis allowed more radial deviation but less ulnar deviation than the PRC. The average peak tendon force was significantly greater after 4-corner arthrodesis than after PRC for the extensor carpi ulnaris during wrist flexion-extension, circumduction, and dart throw motions. The peak forces were significantly greater after 4-corner arthrodesis than in the intact wrist for the extensor carpi ulnaris during the dart throw motion and for the flexor carpi ulnaris during the circumduction motion. The peak extensor carpi radialis brevis force after PRC was significantly less than in the intact wrist. The measured wrist extremes of motion decreased after both 4-corner arthrodesis and PRC. Larger peak tendon forces were required to achieve identical wrist motions with the 4-corner arthrodesis compared with the intact wrist. We observed smaller forces for the PRC. These results may help explain why PRC shows early clinical improvement, yet may lead to degenerative arthritis. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Assessing the risk of nitrogen deposition to natural resources in the Four Corners area

USGS Publications Warehouse

Reed, Sasha C.; Belnap, Jayne; Floyd-Hanna, Lisa; Crews, Tim; Herring, Jack; Hanna, Dave; Miller, Mark E.; Duniway, Michael C.; Roybal, Carla M.

2013-01-01

Nitrogen (N) deposition in the western U.S. is on the rise and is already dramatically affecting terrestrial ecosystems. For example, N deposition has repeatedly been shown to lower air and water quality, increase greenhouse gas emissions, alter plant community composition, and significantly modify fire regimes. Accordingly, the effects of N deposition represent one of our largest environmental challenges and make difficult the National Park Service’s (NPS) important mission to “preserve the scenery and the natural and historic objects and the wildlife… unimpaired for the enjoyment of future generations”. Due to increased population growth and energy development (e.g., natural gas wells), the Four Corners region has become a notable ‘hotspot’ for N deposition. However, our understanding of how increased N deposition will affect these unique ecosystems, as well as how much deposition is actually occurring, remains notably poor. Here we used a multi-disciplinary approach to gathering information in an effort to help NPS safeguard the Four Corners national parks, both now and into the future. We applied modeling, field, and laboratory techniques to clarify current N deposition gradients and to help elucidate the ecosystem consequences of N deposition to the national parks of the Four Corners area. Our results suggest that NOx deposition does indeed represent a significant source of N to Mesa Verde National Park and, as expected, N deposition significantly affects coupled biogeochemical cycling (N, carbon, and phosphorus) of these landscapes. We also found some surprising results. For example, perhaps due to the low nutrient availability in these (and other) dryland ecosystems, although most other research suggests that adding N reduces N fixation rates, N additions did not consistently reduce natural N inputs via biological N2 fixation at our dryland sites. While the timeline of this pilot project is too brief to elucidate all the potential insight from the approach utilized here (e.g., we have fertilization plots to explore how N deposition affects Bromus tectorum invasion that will surely yield provoking results), we plan to continue this exciting line of questioning and expect further insight to be forthcoming.

11. VIEW NORTHEAST, DETAIL OF BRIDGE BEARING AT SOUTHEAST CORNER, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. VIEW NORTHEAST, DETAIL OF BRIDGE BEARING AT SOUTHEAST CORNER, SHOWING WELDED REINFORCEMENT - Perkins Corner Bridge, Spanning Willimantic River at Flanders & Cider Mill Roads, Coventry, Tolland County, CT

51. Ground floor, southeast corner, looking southeast in mezzanine (original ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

51. Ground floor, southeast corner, looking southeast in mezzanine (original function unknown) - Sheffield Farms Milk Plant, 1075 Webster Avenue (southwest corner of 166th Street), Bronx, Bronx County, NY

Corner store purchases made by adults, adolescents and children: items, nutritional characteristics and amount spent.

PubMed

Lent, Michelle R; Vander Veur, Stephanie; Mallya, Giridhar; McCoy, Tara A; Sanders, Timothy A; Colby, Lisa; Rauchut Tewksbury, Colleen; Lawman, Hannah G; Sandoval, Brianna; Sherman, Sandy; Wylie-Rosett, Judith; Foster, Gary D

2015-06-01

Corner stores, also known as bodegas, are prevalent in low-income urban areas and primarily stock high-energy foods and beverages. Little is known about individual-level purchases in these locations. The purpose of the present study was to assess corner store purchases (items, nutritional characteristics and amount spent) made by children, adolescents and adults in a low-income urban environment. Evaluation staff used 9238 intercept surveys to directly examine food and beverage purchases. Intercepts were collected at 192 corner stores in Philadelphia, PA, USA. Participants were adult, adolescent and child corner store shoppers. Among the 9238 intercept surveys, there were 20 244 items. On average, at each corner store visit, consumers purchased 2.2 (sd 2.1) items (1.3 (sd 2.0) foods and 0.9 (sd 0.9) beverages) that cost $US 2.74 (sd $US 3.52) and contained 2786.5 (sd 4454.2) kJ (666.0 (sd 1064.6) kcal). Whether the data were examined as a percentage of total items purchased or as a percentage of intercepts, the most common corner store purchases were beverages, chips, prepared food items, pastries and candy. Beverage purchases occurred during 65.9% of intercepts and accounted for 39.2% of all items. Regular soda was the most popular beverage purchase. Corner store purchases averaged 66.2 g of sugar, 921.1 mg of sodium and 2.5 g of fibre per intercept. Compared with children and adolescents, adults spent the most money and purchased the most energy. Urban corner store shoppers spent almost $US 3.00 for over 2700 kJ (650 kcal) per store visit. Obesity prevention efforts may benefit from including interventions aimed at changing corner store food environments in low-income, urban areas.

Copper(II) sorption onto goethite, hematite and lepidocrocite: a surface complexation model based on ab initio molecular geometries and EXAFS spectroscopy

NASA Astrophysics Data System (ADS)

Peacock, Caroline L.; Sherman, David M.

2004-06-01

We measured the adsorption of Cu(II) onto goethite (α-FeOOH), hematite (α-Fe 2O 3) and lepidocrocite (γ-FeOOH) from pH 2-7. EXAFS spectra show that Cu(II) adsorbs as (CuO 4H n) n-6 and binuclear (Cu 2O 6H n) n-8 complexes. These form inner-sphere complexes with the iron (hydr)oxide surfaces by corner-sharing with two or three edge-sharing Fe(O,OH) 6 polyhedra. Our interpretation of the EXAFS data is supported by ab initio (density functional theory) geometries of analogue Fe 2(OH) 2(H 2O) 8Cu(OH) 4and Fe 3(OH) 4(H 2O) 10Cu 2(OH) 6 clusters. We find no evidence for surface complexes resulting from either monodentate corner-sharing or bidentate edge-sharing between (CuO 4H n) n-6 and Fe(O,OH) 6 polyhedra. Sorption isotherms and EXAFS spectra show that surface precipitates have not formed even though we are supersaturated with respect to CuO and Cu(OH) 2. Having identified the bidentate (FeOH) 2Cu(OH) 20 and tridentate (Fe 3O(OH) 2)Cu 2(OH) 30 surface complexes, we are able to fit the experimental copper(II) adsorption data to the reactions 3( FeOH)+2 Cu2++3 H2O=( Fe3O( OH) 2) Cu2( OH) 30+4 H+ and 2( FeOH)+ Cu2++2 H2O=( FeOH) 2Cu( OH) 20+2 H+. The two stability constants are similar for the three iron (hydr)oxide phases investigated.

Source Spectra and Site Response for Two Indonesian Earthquakes: the Tasikmalaya and Kerinci Events of 2009

NASA Astrophysics Data System (ADS)

Gunawan, I.; Cummins, P. R.; Ghasemi, H.; Suhardjono, S.

2012-12-01

Indonesia is very prone to natural disasters, especially earthquakes, due to its location in a tectonically active region. In September-October 2009 alone, intraslab and crustal earthquakes caused the deaths of thousands of people, severe infrastructure destruction and considerable economic loss. Thus, both intraslab and crustal earthquakes are important sources of earthquake hazard in Indonesia. Analysis of response spectra for these intraslab and crustal earthquakes are needed to yield more detail about earthquake properties. For both types of earthquakes, we have analysed available Indonesian seismic waveform data to constrain source and path parameters - i.e., low frequency spectral level, Q, and corner frequency - at reference stations that appear to be little influenced by site response.. We have considered these analyses for the main shocks as well as several aftershocks. We obtain corner frequencies that are reasonably consistent with the constant stress drop hypothesis. Using these results, we consider using them to extract information about site response form other stations form the Indonesian strong motion network that appear to be strongly affected by site response. Such site response data, as well as earthquake source parameters, are important for assessing earthquake hazard in Indonesia.

1. Exterior, corner, wall, and barrel of cannon used to ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Exterior, corner, wall, and barrel of cannon used to protect corner of building from cart wheels. 1960. - Jefferson Barracks, Brick & Stone Powder Magazine, Jefferson Barracks, St. Louis County, MO

Novices "In Story": What First-Year Teachers' Narratives Reveal about the Shady Corners of Teaching

ERIC Educational Resources Information Center

Orland-Barak, Lily; Maskit, Ditza

2011-01-01

In a national contest of story writing in Israel, first-year teachers from all educational sectors were invited to write a story that mirrors their first year of teaching experience. The narrative analysis of the stories sheds light on the hostile and adverse sides of teaching, surfacing novices' sense of impotence in their capacity to act. The…

49 CFR 173.4 - Small quantities for highway and rail.

Code of Federal Regulations, 2011 CFR

2011-10-01

... drops made from a height of 1.8 m (5.9 feet) directly onto a solid unyielding surface without breakage... package: (A) One drop flat on bottom; (B) One drop flat on top; (C) One drop flat on the long side; (D) One drop flat on the short side; and (E) One drop on a corner at the junction of three intersecting...

Summary of a study to determine low-velocity impact damage and residual tension strength for a thick graphite/epoxy motor case

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1990-01-01

Impacters of various shapes and masses were dropped from various heights onto 36 mm (1.4 in.) thick graphite/epoxy cylinders, which represented filament wound cases (FWC) for the booster motors of the Space Shuttle. Insert solid propellant was cast into some of the cylinders. The cylinders were impacted numerous times around the circumference and then cut into 51 mm (2.0 in.) wide tension specimens, each containing an impact site. Four indenters were used: a sharp corner, two hemispheres, and a bolt-like rod. The diameters of the hemispheres were 12.7 mm (0.5 in.) and 25.4 mm (1.0 in.), and the diameter of the rod was 6.3 mm (0.25 in.). Impacts with the rod were simulated by pressing the rod against the face of specimens. For the hemispheres, the damage initiated beneath the surface at a critical contact pressure and was not visible on the surface until an even larger pressure was exceeded. The damage consisted of matrix cracking and broken fiber. The rod and corner made visible surface damage in all tests. For the hemispheres, the tension strength was reduced considerably before the damage was visible on the surface, 30 percent for the 25.4 mm (1.0 in.) diameter hemisphere and 10 percent for the 12.7 mm (0.5 in.) diameter hemisphere. Analytical methods were used to predict the damage and residual tension strength. A factor of safety to account for nonvisible damage was determined.

Summary of a study to determine low-velocity impact damage and residual tension strength for a thick graphite/epoxy motor case

NASA Technical Reports Server (NTRS)

Poe, C. C., Jr.

1990-01-01

Impacters of various shapes and masses were dropped from various heights onto 36 mm (1.4 in.) thick graphite/epoxy cylinders, which represented filament wound cases (FWC) for the booster motors of the Space Shuttle. Insert solid propellant was cast into some of the cylinders. The cylinders were impacted numerous times around the circumference and then cut into 51 mm (2.0 in.) wide tension specimens, each containing an impact site. Four indenters were used: a sharp corner, two hemispheres, and a bolt-like rod. The diameters of the hemispheres were 12.7 mm mm (0.5 in.) and 25.4 mm (1.0 in.), and the diameter of the rod was 6.3 mm (0.25 in.). Impacts with the rod were simulated by pressing the rod against the face of specimens. For the hemispheres, the damage initiated beneath the surface at a critical contact pressure and was not visible on the surface until an even larger pressure was exceeded. The damage consisted of matrix cracking and broken fiber. The rod an corner made visible surface damage in all tests. For the hemispheres, the tension strength was reduced considerably before the damage was visible on the surface, 30 percent for the 25.4 mm (1.0 in.) diameter hemisphere and 10 percent for the 12.7 mm (0.5 in.) diameter hemisphere. Analytical methods were used to predict the damage and residual tension strength. A factor of safety to account for nonvisible damage was determined.

Corner Store Inventories, Purchases, and Strategies for Intervention: A Review of the Literature

PubMed Central

Langellier, Brent A; Garza, Jeremiah R; Prelip, Michael L; Glik, Deborah; Brookmeyer, Ron; Ortega, Alexander N

2014-01-01

Introduction An increasingly popular strategy to improving the food retail environment and promoting healthy eating in low-income and minority communities is the corner store conversion. This approach involves partnering with small ‘corner’ food stores to expand access to high-quality fruits, vegetables, and other healthy foods. Methods We conducted a structured review of the literature to assess inventories and sales in corner stores, as well as to identify intervention strategies employed by corner store conversions. Results Our review returned eight descriptive studies that discussed corner store inventories and sales, as well as ten intervention studies discussing six unique corner store conversion interventions in the United States, the Marshall Islands, and Canada. Common intervention strategies included: 1) partnering with an existing store, 2) stocking healthy foods, and 3) social marketing and nutrition education. We summarize each strategy and review the effectiveness of overall corner store conversions at changing peoples’ food purchasing, preparation, and consumption behaviors. Conclusions Consumption of fresh, healthy, affordable foods could be improved by supporting existing retailers to expand their selection of healthy foods and promoting healthy eating at the neighborhood level. Additional corner store conversions should be conducted to determine the effectiveness and importance of specific intervention strategies. PMID:25374481

Distributed coupling high efficiency linear accelerator

DOEpatents

Tantawi, Sami G.; Neilson, Jeffrey

2016-07-19

A microwave circuit for a linear accelerator includes multiple monolithic metallic cell plates stacked upon each other so that the beam axis passes vertically through a central acceleration cavity of each plate. Each plate has a directional coupler with coupling arms. A first coupling slot couples the directional coupler to an adjacent directional coupler of an adjacent cell plate, and a second coupling slot couples the directional coupler to the central acceleration cavity. Each directional coupler also has an iris protrusion spaced from corners joining the arms, a convex rounded corner at a first corner joining the arms, and a corner protrusion at a second corner joining the arms.

Core shroud corner joints

DOEpatents

Gilmore, Charles B.; Forsyth, David R.

2013-09-10

A core shroud is provided, which includes a number of planar members, a number of unitary corners, and a number of subassemblies each comprising a combination of the planar members and the unitary corners. Each unitary corner comprises a unitary extrusion including a first planar portion and a second planar portion disposed perpendicularly with respect to the first planar portion. At least one of the subassemblies comprises a plurality of the unitary corners disposed side-by-side in an alternating opposing relationship. A plurality of the subassemblies can be combined to form a quarter perimeter segment of the core shroud. Four quarter perimeter segments join together to form the core shroud.

Acute posterior cruciate ligament injuries: effect of location, severity, and associated injuries on surgical management.

PubMed

Anderson, Mark A; Simeone, F Joseph; Palmer, William E; Chang, Connie Y

2018-06-01

To correlate MRI findings of patients with posterior cruciate ligament (PCL) injury and surgical management. A retrospective search yielded 79 acute PCL injuries (36 ± 16 years old, 21 F, 58 M). Two independent readers graded PCL tear location (proximal, middle, or distal third) and severity (low-grade or high-grade partial/complete) and evaluated injury of other knee structures. When available, operative reports were examined and the performed surgical procedure was compared with injury grade, location, and presence of associated injuries. The most commonly injured knee structures in acute PCL tears were posterolateral corner (58/79, 73%) and anterior cruciate ligament (ACL) (48/79, 61%). Of the 64 patients with treatment information, 31/64 (48%) were managed surgically: 12/31 (39%) had PCL reconstruction, 13/31 (42%) had ACL reconstruction, 10/31 (32%) had posterolateral corner reconstruction, 9/31 (29%) had LCL reconstruction, 8/31 (26%) had meniscectomy, and 8/31 (26%) had fixation of a fracture. Proximal third PCL tear and multiligamentous injury were more commonly associated with surgical management (P < 0.05). Posterolateral and posteromedial corner, ACL, collateral ligament, meniscus, patellar retinaculum, and gastrocnemius muscle injury, and fracture were more likely to result in surgical management (P < 0.05). Patients with high-grade partial/complete PCL tear were more likely to have PCL reconstruction as a portion of surgical management (P < 0.05). Location of PCL tear and presence of other knee injuries were associated with surgical management while high-grade/complete PCL tear grade was associated with PCL reconstruction. MRI reporting of PCL tear location, severity, and of other knee structure injuries is important for guiding clinical management.

23. SOUTHWEST CORNER OF BUILDING 220 (ENTRY CONTROL BUILDING) IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. SOUTHWEST CORNER OF BUILDING 220 (ENTRY CONTROL BUILDING) IN ASSEMBLY AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

26. SOUTH CORNER OF BUILDING 227 (FIRE STATION) IN ASSEMBLY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. SOUTH CORNER OF BUILDING 227 (FIRE STATION) IN ASSEMBLY AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

32. NORTHEAST CORNER OF BUILDING 232 (MINE SHOP) IN ASSEMBLY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. NORTHEAST CORNER OF BUILDING 232 (MINE SHOP) IN ASSEMBLY AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

34. SOUTHWEST CORNER OF BUILDING 233 (MISSILE ASSEMBLY SHOP) IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

34. SOUTHWEST CORNER OF BUILDING 233 (MISSILE ASSEMBLY SHOP) IN ASSEMBLY AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

30. EAST CORNER OF BUILDING 229 (ELECTRIC POWER STATION) IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. EAST CORNER OF BUILDING 229 (ELECTRIC POWER STATION) IN ASSEMBLY AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

FACILITY 810, CORNER ENTRY TO UNIT B, OBLIQUE VIEW FACING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FACILITY 810, CORNER ENTRY TO UNIT B, OBLIQUE VIEW FACING SOUTH-SOUTHWEST. - Schofield Barracks Military Reservation, Duplex Housing Type with Corner Entries, Between Hamilton & Tidball Streets near Williston Avenue, Wahiawa, Honolulu County, HI

62. SOUTH CORNER OF BUILDING 372 (HAZARDOUS STORAGE) IN BASE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

62. SOUTH CORNER OF BUILDING 372 (HAZARDOUS STORAGE) IN BASE SPARES AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

5. SOUTHEAST CORNER OF BUILDING 260 (STORAGE STRUCTURE A) IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. SOUTHEAST CORNER OF BUILDING 260 (STORAGE STRUCTURE A) IN STORAGE AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

2. SOUTHWEST CORNER OF BUILDING 259 (NORTH SENTRY POST) IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. SOUTHWEST CORNER OF BUILDING 259 (NORTH SENTRY POST) IN STORAGE AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

12. NORTHWEST CORNER OF STORAGE MAGAZINE (BUILDING 342) IN STORAGE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. NORTHWEST CORNER OF STORAGE MAGAZINE (BUILDING 342) IN STORAGE AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

17. NORTHEAST CORNER OF BUILDING 345 (ENTRY CONTROL BUILDING) IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. NORTHEAST CORNER OF BUILDING 345 (ENTRY CONTROL BUILDING) IN STORAGE AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qingcheng, E-mail: qiy9@pitt.edu; To, Albert C., E-mail: albertto@pitt.edu

Surface effects have been observed to contribute significantly to the mechanical response of nanoscale structures. The newly proposed energy-based coarse-grained atomistic method Multiresolution Molecular Mechanics (MMM) (Yang, To (2015), ) is applied to capture surface effect for nanosized structures by designing a surface summation rule SR{sup S} within the framework of MMM. Combined with previously proposed bulk summation rule SR{sup B}, the MMM summation rule SR{sup MMM} is completed. SR{sup S} and SR{sup B} are consistently formed within SR{sup MMM} for general finite element shape functions. Analogous to quadrature rules in finite element method (FEM), the key idea to themore » good performance of SR{sup MMM} lies in that the order or distribution of energy for coarse-grained atomistic model is mathematically derived such that the number, position and weight of quadrature-type (sampling) atoms can be determined. Mathematically, the derived energy distribution of surface area is different from that of bulk region. Physically, the difference is due to the fact that surface atoms lack neighboring bonding. As such, SR{sup S} and SR{sup B} are employed for surface and bulk domains, respectively. Two- and three-dimensional numerical examples using the respective 4-node bilinear quadrilateral, 8-node quadratic quadrilateral and 8-node hexahedral meshes are employed to verify and validate the proposed approach. It is shown that MMM with SR{sup MMM} accurately captures corner, edge and surface effects with less 0.3% degrees of freedom of the original atomistic system, compared against full atomistic simulation. The effectiveness of SR{sup MMM} with respect to high order element is also demonstrated by employing the 8-node quadratic quadrilateral to solve a beam bending problem considering surface effect. In addition, the introduced sampling error with SR{sup MMM} that is analogous to numerical integration error with quadrature rule in FEM is very small. - Highlights: • Surface effect captured by Multiresolution Molecular Mechanics (MMM) is presented. • A novel surface summation rule within the framework of MMM is proposed. • Surface, corner and edges effects are accuterly captured in two and three dimension. • MMM with less 0.3% degrees of freedom of atomistics reproduces atomistic results.« less

Mechanical Behavior of CFRP Lattice Core Sandwich Bolted Corner Joints

NASA Astrophysics Data System (ADS)

Zhu, Xiaolei; Liu, Yang; Wang, Yana; Lu, Xiaofeng; Zhu, Lingxue

2017-12-01

The lattice core sandwich structures have drawn more attention for the integration of load capacity and multifunctional applications. However, the connection of carbon fibers reinforced polymer composite (CFRP) lattice core sandwich structure hinders its application. In this paper, a typical connection of two lattice core sandwich panels, named as corner joint or L-joint, was investigated by experiment and finite element method (FEM). The mechanical behavior and failure mode of the corner joints were discussed. The results showed that the main deformation pattern and failure mode of the lattice core sandwich bolted corner joints structure were the deformation of metal connector and indentation of the face sheet in the bolt holes. The metal connectors played an important role in bolted corner joints structure. In order to save the calculation resource, a continuum model of pyramid lattice core was used to replace the exact structure. The computation results were consistent with experiment, and the maximum error was 19%. The FEM demonstrated the deflection process of the bolted corner joints structure visually. So the simplified FEM can be used for further analysis of the bolted corner joints structure in engineering.

Around the Corner to Better Health: A Milwaukee Corner Store Initiative.

PubMed

Young, Staci; DeNomie, Melissa; Sabir, JoAnne; Gass, Eric; Tobin, Jessie

2017-01-01

To discuss successes and challenges of a collaborative pilot project to increase healthy food availability in corner stores in Milwaukee, Wisconsin. The Lindsay Heights Healthy Corner Store Initiative aimed to help corner stores sell high-quality produce by increasing supply of healthy foods and funding minor store upgrades to facilitate change. Evaluation research. Milwaukee, Wisconsin. Corner stores; youth and adult community members. (1) Supporting businesses in purchasing equipment to stock fresh produce, (2) connecting stores with produce sources, and (3) community outreach and marketing. Partnership capacity, youth engagement in food justice, and community members' usage of corner stores. Qualitative analysis; descriptive statistics. Storeowners reported more sold produce items per week and increased noticeable fresh produce upon entrance into the store. There was increased or improved store redesign, fresh produce signage, in-store cooking demonstrations, and small business development resources. Youth learned about new vegetables, increased kitchen skills and proper food storage, and the effects of obesity on overall health. Similar interventions must address infrastructure costs, cooperation with property owners, and local policies and regulations affecting business practices.

CFD Analysis of a Finite Linear Array of Savonius Wind Turbines

NASA Astrophysics Data System (ADS)

Belkacem, Belabes; Paraschivoiu, Marius

2016-09-01

Vertical axis wind turbines such as Savonius rotors have been shown to be suitable for low wind speeds normally associated with wind resources in all corners of the world. However, the efficiency of the rotor is low. This paper presents results of Computational Fluid Dynamics (CFD) simulations for an array of Savonius rotors that show a significant increase in efficiency. It looks at identifying the effect on the energy yield of a number of turbines placed in a linear array. Results from this investigation suggest that an increase in the energy yield could be achieved which can reach almost two times than the conventional Savonius wind turbine in the case of an array of 11turbines with a distance of 1.4R in between them. The effect of different TSR values and different wind inlet speeds on the farm has been studied for both a synchronous and asynchronous wind farm.

Static and fatigue testing of full-scale fuselage panels fabricated using a Therm-X(R) process

NASA Technical Reports Server (NTRS)

Dinicola, Albert J.; Kassapoglou, Christos; Chou, Jack C.

1992-01-01

Large, curved, integrally stiffened composite panels representative of an aircraft fuselage structure were fabricated using a Therm-X process, an alternative concept to conventional two-sided hard tooling and contour vacuum bagging. Panels subsequently were tested under pure shear loading in both static and fatigue regimes to assess the adequacy of the manufacturing process, the effectiveness of damage tolerant design features co-cured with the structure, and the accuracy of finite element and closed-form predictions of postbuckling capability and failure load. Test results indicated the process yielded panels of high quality and increased damage tolerance through suppression of common failure modes such as skin-stiffener separation and frame-stiffener corner failure. Finite element analyses generally produced good predictions of postbuckled shape, and a global-local modelling technique yielded failure load predictions that were within 7% of the experimental mean.

Behavior of Three Metallic Alloys Under Combined Axial-Shear Stress at 650 C

NASA Technical Reports Server (NTRS)

Colaiuta, Jason F.; Lerch, Bradley (Technical Monitor)

2001-01-01

Three materials, Inconel 718, Haynes 188, and 316 stainless steel, were tested under an axial-torsional stress state at 650 C. The objective of this study was to quantify the evolution of the material while in the viscoplastic domain. Initial and subsequent yield surfaces were experimentally determined to quantify hardening. Subsequent yield surfaces (yield surfaces taken after a preload) had a well-defined front side, in the prestrain direction, but a poorly defined back side, opposite the prestrain direction. Subsequent yield surfaces exhibited isotropic hardening by expansion of the yield surface, kinematic hardening by translation of the yield surface, and distortional hardening by flattening of the yield surface in the direction opposite to the last prestrain. An existing yield function capable of representing isotropic, kinematic, and distortional hardening was used to fit each yield surface. Four variables are used to describe each surface. These variables evolve as the material state changes and have been regressed to the yield surface data.

Friction evaluation of concrete paver blocks for airport pavement applications

NASA Technical Reports Server (NTRS)

Yager, Thomas J.

1992-01-01

The development and use of concrete paver blocks is reviewed and some general specifications for application of this type of pavement surface at airport facilities are given. Two different shapes of interlocking concrete paver blocks installed in the track surface at NASA Langley's Aircraft Landing Dynamics Facility (ALDF) are described. Preliminary cornering performance results from testing of 40 x 14 radial-belted and bias-ply aircraft tires are reviewed. These tire tests are part of a larger, ongoing joint NASA/FAA/Industry Surface Traction and Radial Tire (START) Program involving several different tire sizes. Both dry and wet surface conditions were evaluated on the two concrete paver block test surfaces and a conventional, nongrooved Portland cement concrete surface. Future test plans involving evaluation of other concrete paver block designs at the ALDF are indicated.

50. EAST CORNER OF BUILDING 365 (ARMAMENT TESTING BUILDING) IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

50. EAST CORNER OF BUILDING 365 (ARMAMENT TESTING BUILDING) IN BASE SPARES AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

52. Ground floor, northeast corner, looking northeast at former delivery ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

52. Ground floor, northeast corner, looking northeast at former delivery entries (archways have since been filled in) - Sheffield Farms Milk Plant, 1075 Webster Avenue (southwest corner of 166th Street), Bronx, Bronx County, NY

In-gap corner states in core-shell polygonal quantum rings.

PubMed

Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

2017-01-10

We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states.

In-gap corner states in core-shell polygonal quantum rings

NASA Astrophysics Data System (ADS)

Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

2017-01-01

We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states.

Multi-Objective Sliding Mode Control on Vehicle Cornering Stability with Variable Gear Ratio Actuator-Based Active Front Steering Systems.

PubMed

Ma, Xinbo; Wong, Pak Kin; Zhao, Jing; Xie, Zhengchao

2016-12-28

Active front steering (AFS) is an emerging technology to improve the vehicle cornering stability by introducing an additional small steering angle to the driver's input. This paper proposes an AFS system with a variable gear ratio steering (VGRS) actuator which is controlled by using the sliding mode control (SMC) strategy to improve the cornering stability of vehicles. In the design of an AFS system, different sensors are considered to measure the vehicle state, and the mechanism of the AFS system is also modelled in detail. Moreover, in order to improve the cornering stability of vehicles, two dependent objectives, namely sideslip angle and yaw rate, are considered together in the design of SMC strategy. By evaluating the cornering performance, Sine with Dwell and accident avoidance tests are conducted, and the simulation results indicate that the proposed SMC strategy is capable of improving the cornering stability of vehicles in practice.

Tunable Majorana corner states in a two-dimensional second-order topological superconductor induced by magnetic fields

NASA Astrophysics Data System (ADS)

Zhu, Xiaoyu

2018-05-01

A two-dimensional second-order topological superconductor exhibits a finite gap in both bulk and edges, with the nontrivial topology manifesting itself through Majorana zero modes localized at the corners, i.e., Majorana corner states. We investigate a time-reversal-invariant topological superconductor in two dimensions and demonstrate that an in-plane magnetic field could transform it into a second-order topological superconductor. A detailed analysis reveals that the magnetic field gives rise to mass terms which take distinct values among the edges, and Majorana corner states naturally emerge at the intersection of two adjacent edges with opposite masses. With the rotation of the magnetic field, Majorana corner states localized around the boundary may hop from one corner to a neighboring one and eventually make a full circle around the system when the field rotates by 2 π . In the end, we briefly discuss physical realizations of this system.

Measuring Cyclic Error in Laser Heterodyne Interferometers

NASA Technical Reports Server (NTRS)

Ryan, Daniel; Abramovici, Alexander; Zhao, Feng; Dekens, Frank; An, Xin; Azizi, Alireza; Chapsky, Jacob; Halverson, Peter

2010-01-01

An improved method and apparatus have been devised for measuring cyclic errors in the readouts of laser heterodyne interferometers that are configured and operated as displacement gauges. The cyclic errors arise as a consequence of mixing of spurious optical and electrical signals in beam launchers that are subsystems of such interferometers. The conventional approach to measurement of cyclic error involves phase measurements and yields values precise to within about 10 pm over air optical paths at laser wavelengths in the visible and near infrared. The present approach, which involves amplitude measurements instead of phase measurements, yields values precise to about .0.1 microns . about 100 times the precision of the conventional approach. In a displacement gauge of the type of interest here, the laser heterodyne interferometer is used to measure any change in distance along an optical axis between two corner-cube retroreflectors. One of the corner-cube retroreflectors is mounted on a piezoelectric transducer (see figure), which is used to introduce a low-frequency periodic displacement that can be measured by the gauges. The transducer is excited at a frequency of 9 Hz by a triangular waveform to generate a 9-Hz triangular-wave displacement having an amplitude of 25 microns. The displacement gives rise to both amplitude and phase modulation of the heterodyne signals in the gauges. The modulation includes cyclic error components, and the magnitude of the cyclic-error component of the phase modulation is what one needs to measure in order to determine the magnitude of the cyclic displacement error. The precision attainable in the conventional (phase measurement) approach to measuring cyclic error is limited because the phase measurements are af-

Modeling and calculation of impact friction caused by corner contact in gear transmission

NASA Astrophysics Data System (ADS)

Zhou, Changjiang; Chen, Siyu

2014-09-01

Corner contact in gear pair causes vibration and noise, which has attracted many attentions. However, teeth errors and deformation make it difficulty to determine the point situated at corner contact and study the mechanism of teeth impact friction in the current researches. Based on the mechanism of corner contact, the process of corner contact is divided into two stages of impact and scratch, and the calculation model including gear equivalent error—combined deformation is established along the line of action. According to the distributive law, gear equivalent error is synthesized by base pitch error, normal backlash and tooth profile modification on the line of action. The combined tooth compliance of the first point lying in corner contact before the normal path is inversed along the line of action, on basis of the theory of engagement and the curve of tooth synthetic compliance & load-history. Combined secondarily the equivalent error with the combined deflection, the position standard of the point situated at corner contact is probed. Then the impact positions and forces, from the beginning to the end during corner contact before the normal path, are calculated accurately. Due to the above results, the lash model during corner contact is founded, and the impact force and frictional coefficient are quantified. A numerical example is performed and the averaged impact friction coefficient based on the presented calculation method is validated. This research obtains the results which could be referenced to understand the complex mechanism of teeth impact friction and quantitative calculation of the friction force and coefficient, and to gear exact design for tribology.

Mechanical environmental transport of actinides and ¹³⁷Cs from an arid radioactive waste disposal site.

PubMed

Snow, Mathew S; Clark, Sue B; Morrison, Samuel S; Watrous, Matthew G; Olson, John E; Snyder, Darin C

2015-10-01

Aeolian and pluvial processes represent important mechanisms for the movement of actinides and fission products at the Earth's surface. Soil samples taken in the early 1970's near a Department of Energy radioactive waste disposal site (the Subsurface Disposal Area, SDA, located in southeastern Idaho) provide a case study for studying the mechanisms and characteristics of environmental actinide and (137)Cs transport in an arid environment. Multi-component mixing models suggest actinide contamination within 2.5 km of the SDA can be described by mixing between 2 distinct SDA end members and regional nuclear weapons fallout. The absence of chemical fractionation between (241)Am and (239+240)Pu with depth for samples beyond the northeastern corner and lack of (241)Am in-growth over time (due to (241)Pu decay) suggest mechanical transport and mixing of discrete contaminated particles under arid conditions. Occasional samples northeast of the SDA (the direction of the prevailing winds) contain anomalously high concentrations of Pu with (240)Pu/(239)Pu isotopic ratios statistically identical to those in the northeastern corner. Taken together, these data suggest flooding resulted in mechanical transport of contaminated particles into the area between the SDA and a flood containment dike in the northeastern corner, following which subsequent contamination spreading in the northeastern direction resulted from wind transport of discrete particles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Gaseous Oxidized Mercury Dry Deposition Measurements in the Southwestern USA: A Comparison between Texas, Eastern Oklahoma, and the Four Corners Area

PubMed Central

Sather, Mark E.; Allen, Kara L.; Smith, Luther; Mathew, Johnson; Jackson, Clarence; Callison, Ryan; Scrapper, Larry; Hathcoat, April; Adam, Jacque; Keese, Danielle; Brunette, Robert; Karlstrom, Jason; Van der Jagt, Gerard

2014-01-01

Gaseous oxidized mercury (GOM) dry deposition measurements using aerodynamic surrogate surface passive samplers were collected in central and eastern Texas and eastern Oklahoma, from September 2011 to September 2012. The purpose of this study was to provide an initial characterization of the magnitude and spatial extent of ambient GOM dry deposition in central and eastern Texas for a 12-month period which contained statistically average annual results for precipitation totals, temperature, and wind speed. The research objective was to investigate GOM dry deposition in areas of Texas impacted by emissions from coal-fired utility boilers and compare it with GOM dry deposition measurements previously observed in eastern Oklahoma and the Four Corners area. Annual GOM dry deposition rate estimates were relatively low in Texas, ranging from 0.1 to 0.3 ng/m2h at the four Texas monitoring sites, similar to the 0.2 ng/m2h annual GOM dry deposition rate estimate recorded at the eastern Oklahoma monitoring site. The Texas and eastern Oklahoma annual GOM dry deposition rate estimates were at least four times lower than the highest annual GOM dry deposition rate estimate previously measured in the more arid bordering western states of New Mexico and Colorado in the Four Corners area. PMID:24955412

FRONT ELEVATIONS OF THE HOUSE PAIR AT THE CORNER OF ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FRONT ELEVATIONS OF THE HOUSE PAIR AT THE CORNER OF DIAMOND AND NINETEENTH STREETS, LOOKING NORTH. NO. 1835 IS THE CORNER HOUSE WITH THE TURRET. - 1800 Block Diamond Street (Houses), North side, Philadelphia, Philadelphia County, PA

47. EAST CORNER OF BUILDING 361 (MUNITIONS MAINTENANCE SQUADRON ADMINISTRATION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

47. EAST CORNER OF BUILDING 361 (MUNITIONS MAINTENANCE SQUADRON ADMINISTRATION BUILDING) IN BASE SPARES AREA. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

Diverticula, Diverticulosis, Diverticulitis: What's the Difference?

MedlinePlus

... Publications Library En Español Digestive Health Matters Medical Definitions Links Books of Interest Video Corner Clinical Corner Survey Corner News Medical and Treatment News Events Press Releases Commentary For Media Research Research Awards Research Grants Funding Research Clinical Trials & ...

Image registration based on subpixel localization and Cauchy-Schwarz divergence

NASA Astrophysics Data System (ADS)

Ge, Yongxin; Yang, Dan; Zhang, Xiaohong; Lu, Jiwen

2010-07-01

We define a new matching metric-corner Cauchy-Schwarz divergence (CCSD) and present a new approach based on the proposed CCSD and subpixel localization for image registration. First, we detect the corners in an image by a multiscale Harris operator and take them as initial interest points. And then, a subpixel localization technique is applied to determine the locations of the corners and eliminate the false and unstable corners. After that, CCSD is defined to obtain the initial matching corners. Finally, we use random sample consensus to robustly estimate the parameters based on the initial matching. The experimental results demonstrate that the proposed algorithm has a good performance in terms of both accuracy and efficiency.

Multiscale corner detection and classification using local properties and semantic patterns

NASA Astrophysics Data System (ADS)

Gallo, Giovanni; Giuoco, Alessandro L.

2002-05-01

A new technique to detect, localize and classify corners in digital closed curves is proposed. The technique is based on correct estimation of support regions for each point. We compute multiscale curvature to detect and to localize corners. As a further step, with the aid of some local features, it's possible to classify corners into seven distinct types. Classification is performed using a set of rules, which describe corners according to preset semantic patterns. Compared with existing techniques, the proposed approach inscribes itself into the family of algorithms that try to explain the curve, instead of simple labeling. Moreover, our technique works in manner similar to what is believed are typical mechanisms of human perception.

On the origin of enhanced sensitivity in nanoscale FET-based biosensors

PubMed Central

Shoorideh, Kaveh; Chui, Chi On

2014-01-01

Electrostatic counter ion screening is a phenomenon that is detrimental to the sensitivity of charge detection in electrolytic environments, such as in field-effect transistor-based biosensors. Using simple analytical arguments, we show that electrostatic screening is weaker in the vicinity of concave curved surfaces, and stronger in the vicinity of convex surfaces. We use this insight to show, using numerical simulations, that the enhanced sensitivity observed in nanoscale biosensors is due to binding of biomolecules in concave corners where screening is reduced. We show that the traditional argument, that increased surface area-to-volume ratio for nanoscale sensors is responsible for their increased sensitivity, is incorrect. PMID:24706861

In-gap corner states in core-shell polygonal quantum rings

PubMed Central

Sitek, Anna; Ţolea, Mugurel; Niţă, Marian; Serra, Llorenç; Gudmundsson, Vidar; Manolescu, Andrei

2017-01-01

We study Coulomb interacting electrons confined in polygonal quantum rings. We focus on the interplay of localization at the polygon corners and Coulomb repulsion. Remarkably, the Coulomb repulsion allows the formation of in-gap states, i.e., corner-localized states of electron pairs or clusters shifted to energies that were forbidden for non-interacting electrons, but below the energies of corner-side-localized states. We specify conditions allowing optical excitation to those states. PMID:28071750

38. VIEW OF NORTHWEST CORNER OF STATION 85.5 ANTEROOM SHOWING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

38. VIEW OF NORTHWEST CORNER OF STATION 85.5 ANTEROOM SHOWING HYDRAULIC ACTUATOR ARM (NEAR CEILING) FOR WEST ENVIRONMENTAL DOOR ON NORTH SIDE OF SLC-3W MST. HYDRAULIC PUMP FOR ARM, AND CORNER OF ELEVATOR DOOR VISIBLE IN LOWER LEFT CORNER OF PHOTOGRAPH. WRIGHT SPEEDWAY WINCH MOTOR AND PULLEY FOR RAISING SERVICE PLATFORM ON LEFT. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

A randomized, controlled study of a healthy corner store initiative on the purchases of urban, low-income youth

PubMed Central

Lent, Michelle R.; Veur, Stephanie S. Vander; McCoy, Tara A.; Wojtanowski, Alexis C.; Sandoval, Brianna; Sherman, Sandy; Komaroff, Eugene; Foster, Gary D.

2014-01-01

Objective Although many initiatives exist to improve the availability of healthy foods in corner stores, few randomized trials have assessed their effects. This study evaluated, in a randomized, controlled trial, the effects of a first-generation healthy corner store intervention on students’ food and beverage purchases over a two-year period. Design and Methods Participants (n=767) were 4th-6th grade students. Ten schools and their nearby corner stores (n=24) were randomly assigned to the healthy corner store intervention or an assessment-only control. Intercept surveys directly assessed the nutritional characteristics of students’ corner store purchases at baseline, 1 and 2 years. Students’ weight and heights were measured at baseline, 1 and 2 years. Results There were no differences in energy content per intercept purchased from control or intervention schools at year 1 (p=0.12) or 2 (p=0.58). There were no differences between control and intervention students in BMI-z score (year 1, p=0.83; year 2, p=0. 98) or obesity prevalence (year 1, p=0.96; year 2, p=0.58). Conclusions A healthy corner store initiative did not result in significant changes in the energy content of corner store purchases or in continuous or categorical measures of obesity. These data will help to inform future interventions. PMID:25311881

Geohydrology and water quality of the Inyan Kara, Minnelusa, and Madison aquifers of the northern Black Hills, South Dakota and Wyoming, and Bear Lodge Mountains, Wyoming

USGS Publications Warehouse

Kyllonen, D.P.; Peter, K.D.

1987-01-01

The Inyan Kara, Minnelusa, and Madison aquifers are the principal sources of ground water in the northern Black Hills, South Dakota and Wyoming, and Bear Lodge Mountains, Wyoming. The aquifers are exposed in the Bear Lodge Mountains and the Black Hills and are about 3,000 to 5,000 ft below the land surface in the northeast corner of the study area. The direction of groundwater movement is from the outcrop area toward central South Dakota. Recharge is by infiltration of precipitation and streamflow is by springs and well withdrawals. All three aquifers yield water to flowing wells in some part of the area. Measured and reported well yields in each of the three aquifers exceed 100 gal/min (gpm). A well open to the Minnelusa Formation and the upper part of the Madison Limestone yielded more than 2 ,000 gpm. Water from the Inyan Kara aquifer may require treatment for gross alpha radiation, iron, manganese, sulfate, and hardness before use in public water systems. Water from the Minnelusa aquifer in the northern one-half of the study area may require treatment for sulfate and hardness before use in public water systems. Water from the Madison aquifer in the northern one-half of the study area may require treatment of fluoride, gross alpha radiation, sulfate, and hardness before use in public water systems. Water from the Minnelusa and Madison aquifers in the southern one-half of the study area, though very hard (more than 180 mg/L hardness as calcium carbonate), is suitable for public water systems and irrigation. Flow between the Minnelusa and the Inyan Kara aquifers appears to be insignificant, based on the results of a digital model results. The model indicated there may be significant recharge to the Minnelusa and Madison aquifers by leakage between these two aquifers and perhaps deeper aquifers. (Author 's abstract)

33. SOUTHWEST CORNER OF BUILDING 232 (MINE SHOP) IN ASSEMBLY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. SOUTHWEST CORNER OF BUILDING 232 (MINE SHOP) IN ASSEMBLY AREA WITH INDEPENDENT BLAST WALL AT LEFT. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

Contour-Based Corner Detection and Classification by Using Mean Projection Transform

PubMed Central

Kahaki, Seyed Mostafa Mousavi; Nordin, Md Jan; Ashtari, Amir Hossein

2014-01-01

Image corner detection is a fundamental task in computer vision. Many applications require reliable detectors to accurately detect corner points, commonly achieved by using image contour information. The curvature definition is sensitive to local variation and edge aliasing, and available smoothing methods are not sufficient to address these problems properly. Hence, we propose Mean Projection Transform (MPT) as a corner classifier and parabolic fit approximation to form a robust detector. The first step is to extract corner candidates using MPT based on the integral properties of the local contours in both the horizontal and vertical directions. Then, an approximation of the parabolic fit is calculated to localize the candidate corner points. The proposed method presents fewer false-positive (FP) and false-negative (FN) points compared with recent standard corner detection techniques, especially in comparison with curvature scale space (CSS) methods. Moreover, a new evaluation metric, called accuracy of repeatability (AR), is introduced. AR combines repeatability and the localization error (Le) for finding the probability of correct detection in the target image. The output results exhibit better repeatability, localization, and AR for the detected points compared with the criteria in original and transformed images. PMID:24590354

Contour-based corner detection and classification by using mean projection transform.

PubMed

Kahaki, Seyed Mostafa Mousavi; Nordin, Md Jan; Ashtari, Amir Hossein

2014-02-28

Image corner detection is a fundamental task in computer vision. Many applications require reliable detectors to accurately detect corner points, commonly achieved by using image contour information. The curvature definition is sensitive to local variation and edge aliasing, and available smoothing methods are not sufficient to address these problems properly. Hence, we propose Mean Projection Transform (MPT) as a corner classifier and parabolic fit approximation to form a robust detector. The first step is to extract corner candidates using MPT based on the integral properties of the local contours in both the horizontal and vertical directions. Then, an approximation of the parabolic fit is calculated to localize the candidate corner points. The proposed method presents fewer false-positive (FP) and false-negative (FN) points compared with recent standard corner detection techniques, especially in comparison with curvature scale space (CSS) methods. Moreover, a new evaluation metric, called accuracy of repeatability (AR), is introduced. AR combines repeatability and the localization error (Le) for finding the probability of correct detection in the target image. The output results exhibit better repeatability, localization, and AR for the detected points compared with the criteria in original and transformed images.

Distribution majorization of corner points by reinforcement learning for moving object detection

NASA Astrophysics Data System (ADS)

Wu, Hao; Yu, Hao; Zhou, Dongxiang; Cheng, Yongqiang

2018-04-01

Corner points play an important role in moving object detection, especially in the case of free-moving camera. Corner points provide more accurate information than other pixels and reduce the computation which is unnecessary. Previous works only use intensity information to locate the corner points, however, the information that former and the last frames provided also can be used. We utilize the information to focus on more valuable area and ignore the invaluable area. The proposed algorithm is based on reinforcement learning, which regards the detection of corner points as a Markov process. In the Markov model, the video to be detected is regarded as environment, the selections of blocks for one corner point are regarded as actions and the performance of detection is regarded as state. Corner points are assigned to be the blocks which are seperated from original whole image. Experimentally, we select a conventional method which uses marching and Random Sample Consensus algorithm to obtain objects as the main framework and utilize our algorithm to improve the result. The comparison between the conventional method and the same one with our algorithm show that our algorithm reduce 70% of the false detection.

26 x 6.6 radial-belted aircraft tire performance

NASA Technical Reports Server (NTRS)

Davis, Pamela A.; Martinson, Veloria J.; Yager, Thomas J.; Stubbs, Sandy M.

1991-01-01

Preliminary results from testing of 26 x 6.6 radial-belted and bias-ply aircraft tires at NASA Langley's Aircraft Landing Dynamics Facility (ALDF) are reviewed. The 26 x 6.6 tire size evaluation includes cornering performance tests throughout the aircraft ground operational speed range for both dry and wet runway surfaces. Static test results to define 26 x 6.6 tire vertical stiffness properties are also presented and discussed.

Characterization of microchannel anechoic corners formed by surface acoustic waves

NASA Astrophysics Data System (ADS)

Destgeer, Ghulam; Alam, Ashar; Ahmed, Husnain; Park, Jinsoo; Jung, Jin Ho; Park, Kwangseok; Sung, Hyung Jin

2018-02-01

Surface acoustic waves (SAWs) generated in a piezoelectric substrate couple with a liquid according to Snell's law such that a compressional acoustic wave propagates obliquely at a Rayleigh angle ( θ t) inside the microchannel to form a region devoid of a direct acoustic field, which is termed a microchannel anechoic corner (MAC). In the present study, we used microchannels with various heights and widths to characterize the width of the MAC region formed by a single travelling SAW. The attenuation of high-frequency SAWs produced a strong acoustic streaming flow that moved the particles in and out of the MAC region, whereas reflections of the acoustic waves within the microchannel resulted in standing acoustic waves that trapped particles at acoustic pressure nodes located within or outside of the MAC region. A range of actuation frequencies and particle diameters were used to investigate the effects of the acoustic streaming flow and the direct acoustic radiation forces by the travelling as well as standing waves on the particle motion with respect to the MAC region. The width of the MAC ( w c), measured experimentally by tracing the particles, increased with the height of the microchannel ( h m) according to a simple trigonometric equation w c = h m × tan ( θ t ).

4. CORNER OF LA GRANADA AND PASEO DELICIAS, SERVICE STATION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. CORNER OF LA GRANADA AND PASEO DELICIAS, SERVICE STATION FAR RIGHT. CAPTION NOTES 'CORNER NOW OCCUPIED BY FOUNTAIN LUNCH. FIRST SCHOOL OPENED IN THIS COTTAGE ROOM.' - Garage Block Building, 6033 Paseo Delicias, Rancho Santa Fe, San Diego County, CA

Forecast Model and Product Assessment Project User’s Guide

DTIC Science & Technology

2011-05-01

Domain Filter FIXED LENGTH SECTION...1 0 - don’t filter 1 - return stations within latitude/longitude corners 2 - return...Latitude/Longitude Corners (lines skipped if not Domain Filter 1) -------------------------- CapeC_1_d1 26.000 SW corner latitude

44. NORTHWEST CORNER OF BUILDING 272 (STORAGE STRUCTURE A2) IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

44. NORTHWEST CORNER OF BUILDING 272 (STORAGE STRUCTURE A-2) IN ASSEMBLY AREA SHOWING SHAPE OF EARTHEN BERM. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

Domain wall kinetics of lithium niobate single crystals near the hexagonal corner

NASA Astrophysics Data System (ADS)

Choi, Ju Won; Ko, Do-Kyeong; Yu, Nan Ei; Kitamura, Kenji; Ro, Jung Hoon

2015-03-01

A mesospheric approach based on a simple microscopic 2D Ising model in a hexagonal lattice plane is proposed to explain macroscopic "asymmetric in-out domain wall motion" observation in the (0001) plane of MgO-doped stoichiometric lithium niobate. Under application of an electric field that was higher than the conventional coercive field (Ec) to the ferroelectric crystal, a natural hexagonal domain was obtained with walls that were parallel to the Y-axis of the crystal. When a fraction of the coercive field of around 0.1Ec is applied in the reverse direction, this hexagonal domain is shrunk (moved inward) from the corner site into a shape with a corner angle of around 150° and 15° wall slopes to the Y-axis. A flipped electric field of 0.15Ec is then applied to recover the natural hexagonal shape, and the 150° corner shape changes into a flat wall with 30° slope (moved outward). The differences in corner domain shapes between inward and outward domain motion were analyzed theoretically in terms of corner and wall site energies, which are described using the domain corner angle and wall slope with respect to the crystal Y-axis, respectively. In the inward domain wall motion case, the energy levels of the evolving 150° domain corner and 15° slope walls are most competitive, and could co-exist. In the outward case, the energy levels of corners with angles >180° are highly stable when compared with the possible domain walls; only a flat wall with 30° slope to the Y-axis is possible during outward motion.

Impact of rounded electrode corners on breakdown characteristics of AlGaN/GaN high-electron mobility transistors

NASA Astrophysics Data System (ADS)

Yamazaki, Taisei; Asubar, Joel T.; Tokuda, Hirokuni; Kuzuhara, Masaaki

2018-05-01

We investigated the impact of rounded electrode corners on the breakdown characteristics of AlGaN/GaN high-electron mobility transistors. For standard reference devices, catastrophic breakdown occurred predominantly near the sharp electrode corners. By introducing a rounded-electrode architecture, premature breakdown at the corners was mitigated. Moreover, the rate of breakdown voltage (V BR) degradation with an increasing gate width (W G) was significantly lower for devices with rounded corners. When W G was increased from 100 µm to 10 mm, the V BR of the reference device dropped drastically, from 1,200 to 300 V, whereas that of the rounded-electrode device only decreased to a respectable value of 730 V.

Experiments versus modeling of buoyant drying of porous media

NASA Astrophysics Data System (ADS)

Salin, D.; Yiotis, A.; Tajer, E.; Yortsos, Y. C.

2012-12-01

Experiments versus modeling of buoyant drying of porous media D. Salin and A.G. Yiotis, Laboratoire FAST, Univ Pierre & Marie Curie, Univ. Paris-Sud, CNRS, Orsay 91405, France and E.S. Tajer and Y.C. Yortsos, Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1450 A series of isothermal drying experiments in packed glass beads saturated with volatile hydrocarbons (hexane or pentane) are conducted. The transparent glass cells containing the packing allow for the visual monitoring of the phase distribution patterns below the surface, including the formation of liquid films, as the gaseous phase invades the pore space, and for the control of the thickness of the diffusive mass boundary layer over the packing. We demonstrate the existence of an early Constant Rate Period, CRP, that lasts as long as the films saturate the surface of the packing, and of a subsequent Falling Rate Period, FRP, that begins practically after the detachment of the film tips from the external surface. During the CRP, the process is controlled by diffusion within the stagnant gaseous phase in the upper part of the cells, yielding a Stefan tube problem solution. During the FRP, the process is controlled by diffusion within the packing, with a drying rate inversely proportional to the observed position of the film tips in the cell. The critical residual liquid saturation that marks the transition between these two regimes is found to be a function of the average bead size in our packs and the incline of the cells with respect to the flat vertical, with larger beads and angles closer to the vertical position leading to earlier film detachment times and higher critical saturations. We developed a model for the drying of porous media in the presence of gravity. It incorporated effects of corner film flow, internal and external mass transfer and the effect of gravity. Analytical results were derived when gravity opposes drying and hence leads to a stable percolation drying front. We are thus able to obtain results for the drying rates, the critical saturation and the extent of the film region with respect to the various dimensionless numbers that describe the process; the Bond (Bo)number, a film-based Capillary (Ca) number and the dimensionless extent of the mass boundary layer (Sh). The experimental results agree very well with the theory, provided that the latter is generalized to account for the effects of corner roundness in the film region which were neglected in our analytical approach. The agreement is achieved for a specific value of the roundness of the films, which is found to be constant and equal to 0.2 for various conditions, and verify the theoretical dependence on Ca, Bo and Sh numbers.

20. NORTHWEST CORNER OF BUILDING 216 (AMMUNITION MAINTENANCE SHOP) IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. NORTHWEST CORNER OF BUILDING 216 (AMMUNITION MAINTENANCE SHOP) IN ASSEMBLY AREA SHOWING SHAPE OF EARTHEN MOUND COVERING AND RETAINING WALL. - Loring Air Force Base, Weapons Storage Area, Northeastern corner of base at northern end of Maine Road, Limestone, Aroostook County, ME

Multi-Objective Sliding Mode Control on Vehicle Cornering Stability with Variable Gear Ratio Actuator-Based Active Front Steering Systems

PubMed Central

Ma, Xinbo; Wong, Pak Kin; Zhao, Jing; Xie, Zhengchao

2016-01-01

Active front steering (AFS) is an emerging technology to improve the vehicle cornering stability by introducing an additional small steering angle to the driver’s input. This paper proposes an AFS system with a variable gear ratio steering (VGRS) actuator which is controlled by using the sliding mode control (SMC) strategy to improve the cornering stability of vehicles. In the design of an AFS system, different sensors are considered to measure the vehicle state, and the mechanism of the AFS system is also modelled in detail. Moreover, in order to improve the cornering stability of vehicles, two dependent objectives, namely sideslip angle and yaw rate, are considered together in the design of SMC strategy. By evaluating the cornering performance, Sine with Dwell and accident avoidance tests are conducted, and the simulation results indicate that the proposed SMC strategy is capable of improving the cornering stability of vehicles in practice. PMID:28036037

Accurate Analysis of Target Characteristic in Bistatic SAR Images: A Dihedral Corner Reflectors Case.

PubMed

Ao, Dongyang; Li, Yuanhao; Hu, Cheng; Tian, Weiming

2017-12-22

The dihedral corner reflectors are the basic geometric structure of many targets and are the main contributions of radar cross section (RCS) in the synthetic aperture radar (SAR) images. In stealth technologies, the elaborate design of the dihedral corners with different opening angles is a useful approach to reduce the high RCS generated by multiple reflections. As bistatic synthetic aperture sensors have flexible geometric configurations and are sensitive to the dihedral corners with different opening angles, they specially fit for the stealth target detections. In this paper, the scattering characteristic of dihedral corner reflectors is accurately analyzed in bistatic synthetic aperture images. The variation of RCS with the changing opening angle is formulated and the method to design a proper bistatic radar for maximizing the detection capability is provided. Both the results of the theoretical analysis and the experiments show the bistatic SAR could detect the dihedral corners, under a certain bistatic angle which is related to the geometry of target structures.

Corners in M-theory

NASA Astrophysics Data System (ADS)

Sati, Hisham

2011-06-01

M-theory can be defined on closed manifolds as well as on manifolds with boundary. As an extension, we show that manifolds with corners appear naturally in M-theory. We illustrate this with four situations: the lift to bounding 12 dimensions of M-theory on anti-de Sitter spaces, ten-dimensional heterotic string theory in relation to 12 dimensions, and the two M-branes within M-theory in the presence of a boundary. The M2-brane is taken with (or as) a boundary and the worldvolume of the M5-brane is viewed as a tubular neighborhood. We then concentrate on the (variant) of the heterotic theory as a corner and explore analytical and geometric consequences. In particular, we formulate and study the phase of the partition function in this setting and identify the corrections due to the corner(s). The analysis involves considering M-theory on disconnected manifolds and makes use of the extension of the Atiyah-Patodi-Singer index theorem to manifolds with corners and the b-calculus of Melrose.

Accurate Analysis of Target Characteristic in Bistatic SAR Images: A Dihedral Corner Reflectors Case

PubMed Central

Ao, Dongyang; Hu, Cheng; Tian, Weiming

2017-01-01

The dihedral corner reflectors are the basic geometric structure of many targets and are the main contributions of radar cross section (RCS) in the synthetic aperture radar (SAR) images. In stealth technologies, the elaborate design of the dihedral corners with different opening angles is a useful approach to reduce the high RCS generated by multiple reflections. As bistatic synthetic aperture sensors have flexible geometric configurations and are sensitive to the dihedral corners with different opening angles, they specially fit for the stealth target detections. In this paper, the scattering characteristic of dihedral corner reflectors is accurately analyzed in bistatic synthetic aperture images. The variation of RCS with the changing opening angle is formulated and the method to design a proper bistatic radar for maximizing the detection capability is provided. Both the results of the theoretical analysis and the experiments show the bistatic SAR could detect the dihedral corners, under a certain bistatic angle which is related to the geometry of target structures. PMID:29271917

Cornering characteristics of the nose-gear tire of the space shuttle orbiter

NASA Technical Reports Server (NTRS)

Vogler, W. A.; Tanner, J. A.

1981-01-01

An experimental investigation was conducted to evaluate cornering characteristics of the 32 x 8.8 nose gear tire of the space shuttle orbiter. Data were obtained on a dry concrete runway at nominal ground speeds ranging from 50 to 100 knots and over a range of tire vertical loads and yaw angles which span the expected envelope of loads and yaw angles to be encountered during space shuttle landing operations. The cornering characteristics investigated included side and drag forces and friction coefficients, aligning and overturning torques, friction force moment arm, and the lateral center of pressure shift. Results of this investigation indicate that the cornering characteristics of the space shuttle nose gear tire are insensitive to variations in ground speed over the range tested. The effects on cornering characteristics of variations in the tire vertical load and yaw angle are as expected. Trends observed are consistent with trends observed during previous cornering tests involving other tire sizes.

Nanoantennas for enhancing and confining the magnetic optical field

NASA Astrophysics Data System (ADS)

Grosjean, Thierry; Mivelle, Mathieu; Baida, Fadi I.; Burr, Geoffrey W.; Fischer, Ulrich C.

2011-05-01

We propose different optical antenna structures for enhancing and confining the magnetic optical field. A common feature of these structures are concave corners in thin metal films as locations of the enhanced magnetic field. This proposal is inspired by Babinet's principle as the concave edges are the complementary structures to convex metal corners, which are known to be locations of a strongly enhanced electric field. Bowtie antennas and the bowtie apertures of appropriate size were shown to exhibit resonances in the infrared frequency range with an especially strong enhancement of the electrical field in the gap between 2 convex metal corners. We show by numerical calculations, that the complementary structures, the complementary bowtie aperture - the diabolo antenna - and the complementary bow tie antenna - two closely spaced triangular apertures in a metal film with a narrow gap between two opposing concave corners - exhibit resonances with a strongly enhanced magnetic field at the narrow metal constriction between the concave corners. We suggest sub-wavelength circuits of concave and convex corners as building blocks of planar metamaterials.

Model for growth of fractal solid state surface and possibility of its verification by means of atomic force microscopy

NASA Astrophysics Data System (ADS)

Kulikov, D. A.; Potapov, A. A.; Rassadin, A. E.; Stepanov, A. V.

2017-10-01

In the paper, methods of verification of models for growth of solid state surface by means of atomic force microscopy are suggested. Simulation of growth of fractals with cylindrical generatrix on the solid state surface is presented. Our mathematical model of this process is based on generalization of the Kardar-Parisi-Zhang equation. Corner stones of this generalization are both conjecture of anisotropy of growth of the surface and approximation of small angles. The method of characteristics has been applied to solve the Kardar-Parisi-Zhang equation. Its solution should be considered up to the gradient catastrophe. The difficulty of nondifferentiability of fractal initial generatrix has been overcome by transition from a mathematical fractal to a physical one.

Orange River, Africa

NASA Image and Video Library

1996-01-20

STS072-738-036 (11-20 Jan. 1996) --- The astronauts used a 70mm handheld camera to expose this frame of the west-flowing Orange River, which constitutes the international boundary between Namibia and the Republic of South Africa. The railroad and highway connecting the two countries is seen as a ribbon crossing the corner of the view. The broad color difference between strong browns/reds in the northern half of the view and lighter yellows in the southern corresponds to two land surfaces. The darker is a higher, flat land surface developed on horizontal Nama Sandstone’s, with rock surfaces widely coated with a dark manganese stain, typical of desert regions. This region is known as Namaqualand and borders the Namib Desert. Where rivers have cut down into this surface, the lighter underlying rock and soil colors show up.

Component having cooling channel with hourglass cross section

DOEpatents

Campbell, Christian X; Lee, Ching-Pang

2015-04-28

A cooling channel (36, 36B, 63-66) cools inner surfaces (48, 50) of exterior walls (41, 43) of a component (20, 60). Interior side surfaces (52, 54) of the channel converge to a waist (W2), forming an hourglass shaped transverse profile (46). The inner surfaces (48, 50) may have fins (44) aligned with the coolant flow (22). The fins may have a transverse profile (56A, 56B) highest at mid-width of the inner surfaces (48, 50). Turbulators (92) may be provided on the side surfaces (52, 54) of the channel, and may urge the coolant flow toward the inner surfaces (48, 50). Each turbulator (92) may have a peak (97) that defines the waist of the cooling channel. Each turbulator may have a convex upstream side (93). These elements increase coolant flow in the corners (C) of the channel to more uniformly and efficiently cool the exterior walls (41, 43).

A view looking northwest toward the southeast corner of the ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

A view looking northwest toward the southeast corner of the building. Just to the right of the corner is an indication of scale - an extended surveyor's rod - Department of Energy, Mound Facility, Electronics Laboratory Building (E Building), One Mound Road, Miamisburg, Montgomery County, OH

The synthesis of high yield Au nanoplate and optimized optical properties

NASA Astrophysics Data System (ADS)

Ni, Yuan; Kan, Caixia; Xu, Juan; Liu, Yang

2018-02-01

The applications of Au nanoplates based on the tunable plasmon properties and enhanced electromagnetic field at the sharp tip and straight edges, have generated a great deal of interest in recent years, especially in the fields of the bio-chemical sensing and imaging. In this review, we focus on the synthesis of nanoscale platelike structures by multiple synthetic strategies (such as thermal solution method, seed-mediated method, seedless method, and some greener methods), and explore corresponding growth mechanism in different synthetic approaches. Other than to review the fabrication of Au nanoplates, the purification strategies are also discussed in order to support the applications in various fields. Modifying synthetic method to obtain well-defined nanoplates can tuned optical absorption from visible to near-infrared region. Moreover, the Au nanoplate dimers (vertex-to-vertex and edge-by-edge assemblies) can induce more specific plasmon properties and stronger localized field due to coupling of interparticles. Compared with 0D quasi-spherical nanoparticles and 1D nanorods, the 2D nanoplates can be applied as a good surface-enhanced Raman scattering (SERS) substrate because of the sharp corners and straight edges. This review will provide background information for the controllable synthesis of anisotropic nanoparticles and advance the application of coupled nanostructures.

Grid-coordinate generation program

USGS Publications Warehouse

Cosner, Oliver J.; Horwich, Esther

1974-01-01

This program description of the grid-coordinate generation program is written for computer users who are familiar with digital aquifer models. The program computes the coordinates for a variable grid -used in the 'Pinder Model' (a finite-difference aquifer simulator), for input to the CalComp GPCP (general purpose contouring program). The program adjusts the y-value by a user-supplied constant in order to transpose the origin of the model grid from the upper left-hand corner to the lower left-hand corner of the grid. The user has the options of, (1.) choosing the boundaries of the plot; (2.) adjusting the z-values (altitudes) by a constant; (3.) deleting superfluous z-values and (4.) subtracting the simulated surfaces from each other to obtain the decline. Output of this program includes the fixed format CNTL data cards and the other data cards required for input to GPCP. The output from GPCP then is used to produce a potentiometric map or a decline map by means of the CalComp plotter.

Numerical Simulation of Supersonic Gap Flow

PubMed Central

Jing, Xu; Haiming, Huang; Guo, Huang; Song, Mo

2015-01-01

Various gaps in the surface of the supersonic aircraft have a significant effect on airflows. In order to predict the effects of attack angle, Mach number and width-to-depth ratio of gap on the local aerodynamic heating environment of supersonic flow, two-dimensional compressible Navier-Stokes equations are solved by the finite volume method, where convective flux of space term adopts the Roe format, and discretization of time term is achieved by 5-step Runge-Kutta algorithm. The numerical results reveal that the heat flux ratio is U-shaped distribution on the gap wall and maximum at the windward corner of the gap. The heat flux ratio decreases as the gap depth and Mach number increase, however, it increases as the attack angle increases. In addition, it is important to find that chamfer in the windward corner can effectively reduce gap effect coefficient. The study will be helpful for the design of the thermal protection system in reentry vehicles. PMID:25635395

STS-48 ESC Earth observation of southwestern corner of the Great Salt Lake

NASA Technical Reports Server (NTRS)

1991-01-01

STS-48 Earth observation of the southwestern corner of the Great Salt Lake, 308 nautical miles below Discovery, Orbiter Vehicle (OV) 103, was provided by the electronic still camera (ESC). While the image is mostly covered with a thin veil of cirrus clouds, many of the surface features can be recognized. The causeway linking the northern tip of the peninsula to the southwest shore of the lake is clearly visible as is the interstate highway. Considerable topographic detail is visible in the snow covered peaks to the south of the lake. The commercial salt pans between the peninsula and the interstate show high contrast with the brightness dependent on the concentration of the brackish water in the pan. Recent heavy rainfall has caused considerable runoff into the lake but the flooding hazard of a few years past no longer exists due to a pumping system that now transfers excess water to the Bonneville Salt Flats. The ESC image was stored on a removable hard disk or small optical disk and

Study of hollow corner retroreflectors for use in a synchronous orbit

NASA Technical Reports Server (NTRS)

Yoder, P. R., Jr.

1975-01-01

The performance of a hollow corner cube retroreflector made up of three mutually perpendicular optically flat mirrors when undergoing the thermal-mechanical strains induced by a spacecraft environment was studied. Of particular interest was a device of 200 square centimeter optical aperture used on a satellite in a synchronous orbit. It was assumed that the reflector always faces the earth. The effects of direct solar irradiance, earthshine, and albedo were considered. The results included the maximum mirror surface temperature during the orbit as well as the worst-case loss of optical performance due to thermally-induced mirror distortions. It was concluded that a device made of three suitably coated flat ULE mirrors, optically contacted to each other and supported mechanically in a nonrigid mount, would be expected to concentrate over 80 percent of the theoretical maximum energy in the central of the far field diffraction pattern. Continued development of the device through a detailed design, fabrication, and test phase was recommended.

Spatiotemporal Modeling of Community Risk

DTIC Science & Technology

2016-03-01

HOUR OF THE DAY .................................... 35 1. Hourly Distribution Summary Analysis .......................... 40 2. Blackstone Corner...Figure 15. Total EMS Calls Compared to Station 5 EMS Calls ...................... 42 Figure 16. Blackstone Corner...Total EMS Calls for the Fresno City Fire Department 2. Blackstone Corner Not all of the coverage area requests for service follow a daytime

Geometrical optics analysis of the structural imperfection of retroreflection corner cubes with a nonlinear conjugate gradient method.

PubMed

Kim, Hwi; Min, Sung-Wook; Lee, Byoungho

2008-12-01

Geometrical optics analysis of the structural imperfection of retroreflection corner cubes is described. In the analysis, a geometrical optics model of six-beam reflection patterns generated by an imperfect retroreflection corner cube is developed, and its structural error extraction is formulated as a nonlinear optimization problem. The nonlinear conjugate gradient method is employed for solving the nonlinear optimization problem, and its detailed implementation is described. The proposed method of analysis is a mathematical basis for the nondestructive optical inspection of imperfectly fabricated retroreflection corner cubes.

Mixer assembly for a gas turbine engine having a pilot mixer with a corner flame stabilizing recirculation zone

NASA Technical Reports Server (NTRS)

Dai, Zhongtao (Inventor); Cohen, Jeffrey M. (Inventor); Fotache, Catalin G. (Inventor)

2012-01-01

A mixer assembly for a gas turbine engine is provided, including a main mixer, and a pilot mixer having an annular housing in which a corner is formed between an aft portion of the housing and a bulkhead wall in which a corner recirculation zone is located to stabilize and anchor the flame of the pilot mixer. The pilot mixer can further include features to cool the annular housing, including in the area of the corner recirculation zone.

Predominance of sperm motion in corners.

PubMed

Nosrati, Reza; Graham, Percival J; Liu, Qiaozhi; Sinton, David

2016-05-23

Sperm migration through the female tract is crucial to fertilization, but the role of the complex and confined structure of the fallopian tube in sperm guidance remains unknown. Here, by confocal imaging microchannels head-on, we distinguish corner- vs. wall- vs. bulk-swimming bull sperm in confined geometries. Corner-swimming dominates with local areal concentrations as high as 200-fold that of the bulk. The relative degree of corner-swimming is strongest in small channels, decreases with increasing channel size, and plateaus for channels above 200 μm. Corner-swimming remains predominant across the physiologically-relevant range of viscosity and pH. Together, boundary-following sperm account for over 95% of the sperm distribution in small rectangular channels, which is similar to the percentage of wall swimmers in circular channels of similar size. We also demonstrate that wall-swimming sperm travel closer to walls in smaller channels (~100 μm), where the opposite wall is within the hydrodynamic interaction length-scale. The corner accumulation effect is more than the superposition of the influence of two walls, and over 5-fold stronger than that of a single wall. These findings suggest that folds and corners are dominant in sperm migration in the narrow (sub-mm) lumen of the fallopian tube and microchannel-based sperm selection devices.

Predominance of sperm motion in corners

PubMed Central

Nosrati, Reza; Graham, Percival J.; Liu, Qiaozhi; Sinton, David

2016-01-01

Sperm migration through the female tract is crucial to fertilization, but the role of the complex and confined structure of the fallopian tube in sperm guidance remains unknown. Here, by confocal imaging microchannels head-on, we distinguish corner- vs. wall- vs. bulk-swimming bull sperm in confined geometries. Corner-swimming dominates with local areal concentrations as high as 200-fold that of the bulk. The relative degree of corner-swimming is strongest in small channels, decreases with increasing channel size, and plateaus for channels above 200 μm. Corner-swimming remains predominant across the physiologically-relevant range of viscosity and pH. Together, boundary-following sperm account for over 95% of the sperm distribution in small rectangular channels, which is similar to the percentage of wall swimmers in circular channels of similar size. We also demonstrate that wall-swimming sperm travel closer to walls in smaller channels (~100 μm), where the opposite wall is within the hydrodynamic interaction length-scale. The corner accumulation effect is more than the superposition of the influence of two walls, and over 5-fold stronger than that of a single wall. These findings suggest that folds and corners are dominant in sperm migration in the narrow (sub-mm) lumen of the fallopian tube and microchannel-based sperm selection devices. PMID:27211846

Nutrition environments in corner stores in Philadelphia.

PubMed

Cavanaugh, Erica; Mallya, Giridhar; Brensinger, Colleen; Tierney, Ann; Glanz, Karen

2013-02-01

To examine the availability, quality, and price of key types of healthy and less-healthy foods found in corner stores in low-income urban neighborhoods and the associations between store characteristics and store food environments. A sample of 246 corner stores was selected from all corner stores participating in the Philadelphia Healthy Corner Store Initiative (HCSI). The Nutrition Environment Measures Survey for Corner Stores (NEMS-CS) was used to assess the availability, quality, and price of foods and beverages in 11 common categories between February and May, 2011. NEMS-CS measures were completed in 233 stores, 94.7% of the 246 stores approached. The healthier options were significantly less available in all food categories and often more expensive. Baked goods, bread, chips and cereals were sold at nearly all stores, with significantly fewer offering low-fat baked goods (5.7%, p<0.0001), whole grain bread (56.2%, p<0.0001), or baked chips (35.2%, p<0.0001). Number of aisles was positively associated with availability score (p<0.05). Findings from this study point toward potential targets for intervention to improve the corner store food environment and dietary choices among low-income urban populations. Availability of certain healthier foods could be improved. Copyright © 2012 Elsevier Inc. All rights reserved.

Simulations of super-ellipse hohlraum targets as a path to high neutron yields

NASA Astrophysics Data System (ADS)

Milovich, Jose; Amendt, Peter; Storm, Erik; Robey, Harry; Haan, Steve; Landen, Otto; Meezan, Nathan; Lindl, John

2017-10-01

Recently neutron yields in excess of 1016 have been achieved at the National Ignition Facility (NIF) using a low-density gas fill hohlraum and a subscale high-density-carbon capsule. The laser power used was near the current maximum level allowed on the inner cones of the NIF laser. While more energy can be extracted from the laser to provide additional improvement on the neutron yield, a more efficient design is desired. A new effort has begun to investigate alternatives to the current cylinder-shaped hohlraum for driving larger capsules (1.1 mm outer radius). If these new hohlraums can preserve the implosion symmetry, the additional absorbed energy is expected to provide a path to high neutron yield and potential ignition. Super-ellipse hohlraums, a generalization of an earlier rugby hohlraum design, have the advantage of a larger waist diameter and reduced parasitic energy losses from the corners of cylindrical hohlraums while still being able to produce the required capsule drive at the current energy and power limits available at the NIF. We will present plausible designs of these hohlraums based on the Lamé mathematical construction, and discuss their prospects to reach high neutron gains. Prepared by LLNL under Contract DE-AC52-07NA27344.

Surface-enhanced Raman scattering from silver nanostructures with different morphologies

NASA Astrophysics Data System (ADS)

Zhang, W. C.; Wu, X. L.; Kan, C. X.; Pan, F. M.; Chen, H. T.; Zhu, J.; Chu, Paul K.

2010-07-01

Scanning electron microscopy and X-ray diffraction reveal that four different types of crystalline silver nanostructures including nanoparticles, nanowires, nanocubes, and bipyramids are synthesized by a solvothermal method by reducing silver nitrate with ethylene glycol using poly(vinylpyrrolidone) as an adsorption agent and adding different quantities of sodium chloride to the solution. These nanostructures which exhibit different surface plasma resonance properties in the ultraviolet-visible region are shown to be good surface-enhanced Raman scattering (SERS) substrates using rhodamine 6G molecules. Our results demonstrate that the silver nanocubes, bipyramids with sharp corners and edges, and aggregated silver nanoparticles possess better SERS properties than the silver nanowires, indicating that they can serve as high-sensitivity substrates in SERS-based measurements.

Shuttle landing runway modification to improve tire spin-up wear performance

NASA Technical Reports Server (NTRS)

Daugherty, Robert H.; Yager, Thomas J.; Stubbs, Sandy M.

1988-01-01

This paper presents the results of a series of tire spin-up wear tests on a simulated Kennedy Space Center (KSC) runway that were carried out to investigate the tire wear problem for Space Shuttle landings on the KSC runway and to test several modifications of the runway surface designed to alleviate the problem. It was found that the runway surface produced by a concrete smoothing machine using cutters spaced one and three-quarters blades per centimeter provided adequate wet cornering while limiting spin-up wear. Based on the test results, the KSC runway was smoothed for about 1066 m at each end, leaving the original high friction surface, for better wet steering and braking, in the 2438-m central section.

Bit error rate tester using fast parallel generation of linear recurring sequences

DOEpatents

Pierson, Lyndon G.; Witzke, Edward L.; Maestas, Joseph H.

2003-05-06

A fast method for generating linear recurring sequences by parallel linear recurring sequence generators (LRSGs) with a feedback circuit optimized to balance minimum propagation delay against maximal sequence period. Parallel generation of linear recurring sequences requires decimating the sequence (creating small contiguous sections of the sequence in each LRSG). A companion matrix form is selected depending on whether the LFSR is right-shifting or left-shifting. The companion matrix is completed by selecting a primitive irreducible polynomial with 1's most closely grouped in a corner of the companion matrix. A decimation matrix is created by raising the companion matrix to the (n*k).sup.th power, where k is the number of parallel LRSGs and n is the number of bits to be generated at a time by each LRSG. Companion matrices with 1's closely grouped in a corner will yield sparse decimation matrices. A feedback circuit comprised of XOR logic gates implements the decimation matrix in hardware. Sparse decimation matrices can be implemented with minimum number of XOR gates, and therefore a minimum propagation delay through the feedback circuit. The LRSG of the invention is particularly well suited to use as a bit error rate tester on high speed communication lines because it permits the receiver to synchronize to the transmitted pattern within 2n bits.

High explosive corner turning performance and the LANL Mushroom test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, L.G.; Seitz, W.L.; Forest, C.A.

1997-09-01

The Mushroom test is designed to characterize the corner turning performance of a new generation of less insensitive booster explosives. The test is described in detail, and three corner turning figures-of-merit are examined using pure TATB (both Livermore`s Ultrafine and a Los Alamos research blend) and PBX9504 as examples.

75 FR 48665 - Heritage Stoney Corners Wind Farm I, LLC; Supplemental Notice That Initial Market-Based Rate...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-11

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER10-2108-000] Heritage Stoney Corners Wind Farm I, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...-referenced proceeding, of Heritage Stoney Corners Wind Farm I, LLC's application for market- based rate...

Shear-Panel Test Fixture Eliminates Corner Stresses

NASA Technical Reports Server (NTRS)

Kiss, J. J.; Farley, G. L.; Baker, D. J.

1984-01-01

New design eliminates corner stresses while maintaining uniform stress across panel. Shear panel test fixture includes eight frames and eight corner pins. Fixture assembled in two halves with shear panel sandwiched in between. Results generated from this fixture will result in good data base for design of efficient aircraft structures and other applications.

Analysis of 2D hyperbolic metamaterial dispersion by elementary excitation coupling

NASA Astrophysics Data System (ADS)

Vaianella, Fabio; Maes, Bjorn

2016-04-01

Hyperbolic metamaterials are examined for many applications thanks to the large density of states and extreme confinement of light they provide. For classical hyperbolic metal/dielectric multilayer structures, it was demon- strated that the properties originate from a specific coupling of the surface plasmon polaritons between the metal/dielectric interfaces. We show a similar analysis for 2D hyperbolic arrays of square (or rectangular) silver nanorods in a TiO2 host. In this case the properties derive from a specific coupling of the plasmons carried by the corners of the nanorods. The dispersion can be seen as the coupling of single rods for a through-metal connection of the corners, as the coupling of structures made of four semi-infinite metallic blocks separated by dielectric for a through-dielectric connection, or as the coupling of two semi-infinite rods for a through-metal and through-dielectric situation. For arrays of small square nanorods the elementary structure that explains the dispersion of the array is the single rod, and for arrays of large square nanorods it is four metallic corners. The medium size square nanorod case is more complicated, because the elementary structure can be one of the three basic designs, depending on the frequency and symmetry of the modes. Finally, we show that for arrays of rectangular nanorods the dispersion is explained by coupling of the two coupled rod structure. This work opens the way for a better understanding of a wide class of metamaterials via their elementary excitations.

New perspectives on self-similarity for shallow thrust earthquakes

NASA Astrophysics Data System (ADS)

Denolle, Marine A.; Shearer, Peter M.

2016-09-01

Scaling of dynamic rupture processes from small to large earthquakes is critical to seismic hazard assessment. Large subduction earthquakes are typically remote, and we mostly rely on teleseismic body waves to extract information on their slip rate functions. We estimate the P wave source spectra of 942 thrust earthquakes of magnitude Mw 5.5 and above by carefully removing wave propagation effects (geometrical spreading, attenuation, and free surface effects). The conventional spectral model of a single-corner frequency and high-frequency falloff rate does not explain our data, and we instead introduce a double-corner-frequency model, modified from the Haskell propagating source model, with an intermediate falloff of f-1. The first corner frequency f1 relates closely to the source duration T1, its scaling follows M0∝T13 for Mw<7.5, and changes to M0∝T12 for larger earthquakes. An elliptical rupture geometry better explains the observed scaling than circular crack models. The second time scale T2 varies more weakly with moment, M0∝T25, varies weakly with depth, and can be interpreted either as expressions of starting and stopping phases, as a pulse-like rupture, or a dynamic weakening process. Estimated stress drops and scaled energy (ratio of radiated energy over seismic moment) are both invariant with seismic moment. However, the observed earthquakes are not self-similar because their source geometry and spectral shapes vary with earthquake size. We find and map global variations of these source parameters.

Full-Scale Experimental Investigation to Quantify Building Component Ignition Vulnerability from Mulch Beds Attacked by Firebrand Showers.

PubMed

Manzello, Samuel L; Suzuki, Sayaka; Nii, Daisaku

2017-03-01

Structure ignition by wind-driven firebrand showers is an important fire spread mechanism in large outdoor fires. Experiments were conducted with three common mulch types (shredded hardwood mulch, Japanese Cypress wood chips, and pine bark nuggets) placed adjacent to realistic-scale reentrant corners. In the first series of experiments, mulch beds were placed adjacent to a re-entrant corner constructed with wood studs and lined with oriented strand board (OSB) as the sheathing. The premise behind conducting experiments with no siding treatments applied was predicated on the notion that bare OSB mulch contact would be a worst-case scenario, and therefore, a wall assembly in the most vulnerable state to mulch ignition. In the second series of experiments, vinyl siding was applied to the re-entrant corner assemblies (wood studs/OSB/moisture barrier/vinyl siding), and the influence of vertical separation distance (102 mm or 203 mm) on wall ignition from adjacent mulch beds was determined. The vertical separation distance was maintained by applying gypsum board to the base of the re-entrant corner. The siding itself did not influence the ignition process for the mulch beds, as the mulch beds were the first to ignite from the firebrand showers. In all experiments, it was observed that firebrands produced smoldering ignition in the mulch beds, this transitioned to flaming ignition, and the re-entrant corner assembly was exposed to the flaming mulch beds. With no siding treatments applied, the flaming mulch beds ignited the re-entrant corner, and ignition was observed to propagate to the back side of re-entrant corner assembly under all wind speeds (6 m/s to 8 m/s). With respect to the re-entrant corners fitted with vinyl siding, the mulch type, vertical separation distance, and wind speed were important parameters as to whether flaming ignition was observed to propagate to the back-side of a reentrant corner assembly. Mulches clearly pose an ignition hazard to structures in large outdoor fires.

Extended Range Passive Wireless Tag System and Method

NASA Technical Reports Server (NTRS)

Fink, Patrick W. (Inventor); Lin, Gregory Y. (Inventor); Kennedy, Timothy F. (Inventor)

2013-01-01

A passive wireless tag assembly comprises a plurality of antennas and transmission lines interconnected with circuitry and constructed and arranged in a Van Atta array or configuration to reflect an interrogator signal in the direction from where it came. The circuitry may comprise at least one surface acoustic wave (SAW)-based circuit that functions as a signal reflector and is operatively connected with an information circuit. In another embodiment, at least one delay circuit and/or at least one passive modulation circuit(s) are utilized. In yet another embodiment, antennas connected to SAW-based devices are mounted to at least one of the orthogonal surfaces of a corner reflector.

Electromagnetic scattering by impedance structures

NASA Technical Reports Server (NTRS)

Balanis, Constantine A.; Griesser, Timothy

1987-01-01

The scattering of electromagnetic waves from impedance structures is investigated, and current work on antenna pattern calculation is presented. A general algorithm for determining radiation patterns from antennas mounted near or on polygonal plates is presented. These plates are assumed to be of a material which satisfies the Leontovich (or surface impedance) boundary condition. Calculated patterns including reflection and diffraction terms are presented for numerious geometries, and refinements are included for antennas mounted directly on impedance surfaces. For the case of a monopole mounted on a surface impedance ground plane, computed patterns are compared with experimental measurements. This work in antenna pattern prediction forms the basis of understanding of the complex scattering mechanisms from impedance surfaces. It provides the foundation for the analysis of backscattering patterns which, in general, are more problematic than calculation of antenna patterns. Further proposed study of related topics, including surface waves, corner diffractions, and multiple diffractions, is outlined.

Polygons on a rotating fluid surface.

PubMed

Jansson, Thomas R N; Haspang, Martin P; Jensen, Kåre H; Hersen, Pascal; Bohr, Tomas

2006-05-05

We report a novel and spectacular instability of a fluid surface in a rotating system. In a flow driven by rotating the bottom plate of a partially filled, stationary cylindrical container, the shape of the free surface can spontaneously break the axial symmetry and assume the form of a polygon rotating rigidly with a speed different from that of the plate. With water, we have observed polygons with up to 6 corners. It has been known for many years that such flows are prone to symmetry breaking, but apparently the polygonal surface shapes have never been observed. The creation of rotating internal waves in a similar setup was observed for much lower rotation rates, where the free surface remains essentially flat [J. M. Lopez, J. Fluid Mech. 502, 99 (2004). We speculate that the instability is caused by the strong azimuthal shear due to the stationary walls and that it is triggered by minute wobbling of the rotating plate.

Healthy versus Unhealthy Suppliers in Food Desert Neighborhoods: A Network Analysis of Corner Stores' Food Supplier Networks.

PubMed

Mui, Yeeli; Lee, Bruce Y; Adam, Atif; Kharmats, Anna Y; Budd, Nadine; Nau, Claudia; Gittelsohn, Joel

2015-11-30

Products in corner stores may be affected by the network of suppliers from which storeowners procure food and beverages. To date, this supplier network has not been well characterized. Using network analysis, we examined the connections between corner stores (n = 24) in food deserts of Baltimore City (MD, USA) and their food/beverage suppliers (n = 42), to determine how different store and supplier characteristics correlated. Food and beverage suppliers fell into two categories: Those providing primarily healthy foods/beverages (n = 15) in the healthy supplier network (HSN) and those providing primarily unhealthy food/beverages (n = 41) in the unhealthy supplier network (UHSN). Corner store connections to suppliers in the UHSN were nearly two times greater (t = 5.23, p < 0.001), and key suppliers in the UHSN core were more diverse, compared to the HSN. The UHSN was significantly more cohesive and densely connected, with corner stores sharing a greater number of the same unhealthy suppliers, compared to HSN, which was less cohesive and sparsely connected (t = 5.82; p < 0.001). Compared to African Americans, Asian and Hispanic corner storeowners had on average -1.53 (p < 0.001) fewer connections to suppliers in the HSN (p < 0.001). Our findings indicate clear differences between corner stores' HSN and UHSN. Addressing ethnic/cultural differences of storeowners may also be important to consider.

Healthy versus Unhealthy Suppliers in Food Desert Neighborhoods: A Network Analysis of Corner Stores’ Food Supplier Networks

PubMed Central

Mui, Yeeli; Lee, Bruce Y.; Adam, Atif; Kharmats, Anna Y.; Budd, Nadine; Nau, Claudia; Gittelsohn, Joel

2015-01-01

Background: Products in corner stores may be affected by the network of suppliers from which storeowners procure food and beverages. To date, this supplier network has not been well characterized. Methods: Using network analysis, we examined the connections between corner stores (n = 24) in food deserts of Baltimore City (MD, USA) and their food/beverage suppliers (n = 42), to determine how different store and supplier characteristics correlated. Results: Food and beverage suppliers fell into two categories: Those providing primarily healthy foods/beverages (n = 15) in the healthy supplier network (HSN) and those providing primarily unhealthy food/beverages (n = 41) in the unhealthy supplier network (UHSN). Corner store connections to suppliers in the UHSN were nearly two times greater (t = 5.23, p < 0.001), and key suppliers in the UHSN core were more diverse, compared to the HSN. The UHSN was significantly more cohesive and densely connected, with corner stores sharing a greater number of the same unhealthy suppliers, compared to HSN, which was less cohesive and sparsely connected (t = 5.82; p < 0.001). Compared to African Americans, Asian and Hispanic corner storeowners had on average −1.53 (p < 0.001) fewer connections to suppliers in the HSN (p < 0.001). Conclusions: Our findings indicate clear differences between corner stores’ HSN and UHSN. Addressing ethnic/cultural differences of storeowners may also be important to consider. PMID:26633434

47 CFR 61.52 - Form, size, type, legibility, etc.

Code of Federal Regulations, 2010 CFR

2010-10-01

... type may not be used. Erasures or alterations in writing must not be made in any tariff publication...-hand corner the name of the issuing carrier; in the upper right-hand corner the FCC number of the tariff, with the page designation directly below; in the lower left-hand corner the issued date; in the...

33 CFR 334.1080 - San Francisco Bay adjacent to northeast corner of Treasure Island; naval restricted area.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false San Francisco Bay adjacent to northeast corner of Treasure Island; naval restricted area. 334.1080 Section 334.1080 Navigation and... RESTRICTED AREA REGULATIONS § 334.1080 San Francisco Bay adjacent to northeast corner of Treasure Island...

A surface structural model for ferrihydrite I: Sites related to primary charge, molar mass, and mass density

NASA Astrophysics Data System (ADS)

Hiemstra, Tjisse; Van Riemsdijk, Willem H.

2009-08-01

A multisite surface complexation (MUSIC) model for ferrihydrite (Fh) has been developed. The surface structure and composition of Fh nanoparticles are described in relation to ion binding and surface charge development. The site densities of the various reactive surface groups, the molar mass, the mass density, the specific surface area, and the particle size are quantified. As derived theoretically, molecular mass and mass density of nanoparticles will depend on the types of surface groups and the corresponding site densities and will vary with particle size and surface area because of a relatively large contribution of the surface groups in comparison to the mineral core of nanoparticles. The nano-sized (˜2.6 nm) particles of freshly prepared 2-line Fh as a whole have an increased molar mass of M ˜ 101 ± 2 g/mol Fe, a reduced mass density of ˜3.5 ± 0.1 g/cm 3, both relatively to the mineral core. The specific surface area is ˜650 m 2/g. Six-line Fh (5-6 nm) has a molar mass of M ˜ 94 ± 2 g/mol, a mass density of ˜3.9 ± 0.1 g/cm 3, and a surface area of ˜280 ± 30 m 2/g. Data analysis shows that the mineral core of Fh has an average chemical composition very close to FeOOH with M ˜ 89 g/mol. The mineral core has a mass density around ˜4.15 ± 0.1 g/cm 3, which is between that of feroxyhyte, goethite, and lepidocrocite. These results can be used to constrain structural models for Fh. Singly-coordinated surface groups dominate the surface of ferrihydrite (˜6.0 ± 0.5 nm -2). These groups can be present in two structural configurations. In pairs, the groups either form the edge of a single Fe-octahedron (˜2.5 nm -2) or are present at a single corner (˜3.5 nm -2) of two adjacent Fe octahedra. These configurations can form bidentate surface complexes by edge- and double-corner sharing, respectively, and may therefore respond differently to the binding of ions such as uranyl, carbonate, arsenite, phosphate, and others. The relatively low PZC of ferrihydrite can be rationalized based on the estimated proton affinity constant for singly-coordinated surface groups. Nanoparticles have an enhanced surface charge. The charging behavior of Fh nanoparticles can be described satisfactory using the capacitance of a spherical Stern layer condenser in combination with a diffuse double layer for flat plates.

The role of lines and corners of geometric figures in recognition performance.

PubMed

Shevelev, Igor A; Kamenkovich, Viktorina M; Sharaev, George A

2003-01-01

A relative role of lines and corners of images of outline geometric figures in recognition performance was studied psychophysically. Probability of correct response to the shape of the whole figure (control) and figures with lines or corners masked to a different extent was compared. Increase in the extent of masking resulted in a drop of recognition performance that was significantly lower for figures without corners, than for figures without part of their lines. The whole 3D figures were recognized better than 2D ones, whereas the opposite relations were observed under conditions of masking. Significant gender difference in a recognition performance was found: men recognize entire and partly masked figures better than women. Possible mechanisms of relatively better recognition of figures with corners than with lines are discussed in connection with finding of high sensitivity of many neurons in the primary visual cortex to line crossing and branching.

Method and system for detecting polygon boundaries of structures in images as particle tracks through fields of corners and pixel gradients

DOEpatents

Paglieroni, David W [Pleasanton, CA; Manay, Siddharth [Livermore, CA

2011-12-20

A stochastic method and system for detecting polygon structures in images, by detecting a set of best matching corners of predetermined acuteness .alpha. of a polygon model from a set of similarity scores based on GDM features of corners, and tracking polygon boundaries as particle tracks using a sequential Monte Carlo approach. The tracking involves initializing polygon boundary tracking by selecting pairs of corners from the set of best matching corners to define a first side of a corresponding polygon boundary; tracking all intermediate sides of the polygon boundaries using a particle filter, and terminating polygon boundary tracking by determining the last side of the tracked polygon boundaries to close the polygon boundaries. The particle tracks are then blended to determine polygon matches, which may be made available, such as to a user, for ranking and inspection.

Geology and hydrology for environmental planning in Washtenaw County, Michigan

USGS Publications Warehouse

Fleck, William B.

1980-01-01

Washteaw County is underlain by glacial deposits that range in thickness from about 50 feet to about 450 feet. Underlying the glacial deposits are sedimentary rocks of Mississippian and Devonian age. The youngest of these rocks are the sandstones of the Marshall Formation in the western part of the county;  the oldest are the limestones of the Detroit River Group in the southeast corner.Sand and gravel deposits in some places in the county may yield more than 500 gallons per minute of water. Approximately 50 percent of the wells tapping the Marshall Formation, the most reliable bedrock aquifer, can yield as much as 60 gallons per minute.Washtenaw County has sand and gravel deposits that are more than 50 feet thick. The deposits are mined in several areas and are of economic importance. In addition, there may be potential for peat production in the western part of the county and for clay production in the eastern part.

A new species of Mastigodiaptomus Light, 1939 from Mexico, with notes of species diversity of the genus (Copepoda, Calanoida, Diaptomidae)

PubMed Central

Gutiérrez-Aguirre, Martha Angélica; Cervantes-Martínez, Adrián

2016-01-01

Abstract A new species of the genus Mastigodiaptomus Light, 1939, named Mastigodiaptomus cuneatus sp. n. was found in a freshwater system in the City of Mazatlán, in the northern region of Mexico. Morphologically, the females of this new species are distinguishable from those of its congeners by the following combination of features: the right distal corner of the genital double-somite and second urosomite have a wedge-shaped projection, the fourth urosomite has no dorsal projection and its integument is smooth. The males are distinct by the following features: the right caudal ramus has a wedge-shaped structure at the disto-ventral inner corner; the basis of the right fifth leg has one triangular and one rounded projection at the distal and proximal margins, respectively, plus one hyaline membrane on the caudal surface close to the inner margin; the aculeus length is almost the width of the right second exopod (Exp2); and the frontal and caudal surfaces of the right Exp2 are smooth. Furthermore, the analysis of the COI gene of Mastigodiaptomus cuneatus sp. n. has revealed that Mastigodiaptomus albuquerquensis (Herrick, 1895) is its nearest congener, with 18.64% of genetic distance. A key for the identification of the known species of the genus is provided. PMID:28138275

surf3d: A 3-D finite-element program for the analysis of surface and corner cracks in solids subjected to mode-1 loadings

NASA Technical Reports Server (NTRS)

Raju, I. S.; Newman, J. C., Jr.

1993-01-01

A computer program, surf3d, that uses the 3D finite-element method to calculate the stress-intensity factors for surface, corner, and embedded cracks in finite-thickness plates with and without circular holes, was developed. The cracks are assumed to be either elliptic or part eliptic in shape. The computer program uses eight-noded hexahedral elements to model the solid. The program uses a skyline storage and solver. The stress-intensity factors are evaluated using the force method, the crack-opening displacement method, and the 3-D virtual crack closure methods. In the manual the input to and the output of the surf3d program are described. This manual also demonstrates the use of the program and describes the calculation of the stress-intensity factors. Several examples with sample data files are included with the manual. To facilitate modeling of the user's crack configuration and loading, a companion program (a preprocessor program) that generates the data for the surf3d called gensurf was also developed. The gensurf program is a three dimensional mesh generator program that requires minimal input and that builds a complete data file for surf3d. The program surf3d is operational on Unix machines such as CRAY Y-MP, CRAY-2, and Convex C-220.

Flexible corner cube retroreflector array for temperature and strain sensing† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7ra13284k

PubMed Central

Khalid, Muhammad Waqas; Ahmed, Rajib; Yetisen, Ali K.

2018-01-01

Optical sensors for detecting temperature and strain play a crucial role in the analysis of environmental conditions and real-time remote sensing. However, the development of a single optical device that can sense temperature and strain simultaneously remains a challenge. Here, a flexible corner cube retroreflector (CCR) array based on passive dual optical sensing (temperature and strain) is demonstrated. A mechanical embossing process was utilised to replicate a three-dimensional (3D) CCR array in a soft flexible polymer film. The fabricated flexible CCR array samples were experimentally characterised through reflection measurements followed by computational modelling. As fabricated samples were illuminated with a monochromatic laser beam (635, 532, and 450 nm), a triangular shape reflection was obtained at the far-field. The fabricated flexible CCR array samples tuned retroreflected light based on external stimuli (temperature and strain as an applied force). For strain and temperature sensing, an applied force and temperature, in the form of weight suspension, and heat flow was applied to alter the replicated CCR surface structure, which in turn changed its optical response. Directional reflection from the heated flexible CCR array surface was also measured with tilt angle variation (max. up to 10°). Soft polymer CCRs may have potential in remote sensing applications, including measuring the temperature in space and in nuclear power stations. PMID:29568510

The Boston Middle School-Corner Store Initiative: Development, Implementation, and Initial Evaluation of a Program Designed to Improve Adolescents' Beverage-Purchasing Behaviors

ERIC Educational Resources Information Center

Hoffman, Jessica A.; Morris, Vivien; Cook, John

2009-01-01

The Boston Middle School Corner Store Initiative (CSI) brought together schools, businesses, and community partners to develop, implement, and evaluate a multicomponent pilot program designed to promote healthier beverage purchasing at corner stores among 3,500 middle school students living in Boston, Massachusetts. Healthy drinks were defined for…

47 CFR 61.52 - Form, size, type, legibility, etc.

Code of Federal Regulations, 2012 CFR

2012-10-01

...,” “Original page 1,” “Original page 2,” etc. (1) All such pages must show, in the upper left-hand corner the... designation directly below; in the lower left-hand corner the issued date; in the lower right-hand corner the... and check sheet only. (2) As an alternative, the issuing carrier may show in the upper left-hand...

47 CFR 61.52 - Form, size, type, legibility, etc.

Code of Federal Regulations, 2014 CFR

2014-10-01

...,” “Original page 1,” “Original page 2,” etc. (1) All such pages must show, in the upper left-hand corner the... designation directly below; in the lower left-hand corner the issued date; in the lower right-hand corner the... and check sheet only. (2) As an alternative, the issuing carrier may show in the upper left-hand...

47 CFR 61.52 - Form, size, type, legibility, etc.

Code of Federal Regulations, 2013 CFR

2013-10-01

...,” “Original page 1,” “Original page 2,” etc. (1) All such pages must show, in the upper left-hand corner the... designation directly below; in the lower left-hand corner the issued date; in the lower right-hand corner the... and check sheet only. (2) As an alternative, the issuing carrier may show in the upper left-hand...

The Pause That Refreshes: A Study of the Discovery Corners in the National Museum of History and Technology Smithsonian Institution.

ERIC Educational Resources Information Center

Wolf, Robert L.; Tymitz, Barbara L.

This report examines the impact and effectiveness of an educational program (Discovery Corners) offered by the National Museum of History and Technology. The main objective is to offer feedback to museum personnel regarding the impact of museum exhibits and programs. The Discovery Corners program involves on-site presentations and demonstrations…

In Defense of Education's "Wild West": Charter Schools Thrive in the Four Corners States

ERIC Educational Resources Information Center

Ladner, Matthew

2018-01-01

The point at which the corners of Arizona, Colorado, New Mexico, and Utah meet is the only spot in the United States where the borders of four states converge. Beyond geography, the Four Corners states share a similar approach to charter schooling. All four states have adopted relatively freewheeling authorization policies, and charter schools…

47 CFR 61.52 - Form, size, type, legibility, etc.

Code of Federal Regulations, 2011 CFR

2011-10-01

...,” “Original page 1,” “Original page 2,” etc. (1) All such pages must show, in the upper left-hand corner the... designation directly below; in the lower left-hand corner the issued date; in the lower right-hand corner the... and check sheet only. (2) As an alternative, the issuing carrier may show in the upper left-hand...

Thin walled channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowther, R.L.; Johansson, E.B.

1988-06-07

A fuel assembly is described comprising fuel rods positioned in a spaced array by upper and lower tie-plates, an open ended flow channel surrounding the array for conducting coolant upward about the fuel rods, the open ended channel having a polygon shaped cross section with flat side sections connected between the corner sections; means separate from the channel connecting the upper and lower tie-plates together and maintaining the fuel rods in spaced array independent of the flow channel, improvement in the flow channel comprising: four corners having a first thickness; four sides having a second and reduced thickness from themore » corner thickness, the sides welded to the corner sections.« less

Hiding Techniques for Dynamic Encryption Text based on Corner Point

NASA Astrophysics Data System (ADS)

Abdullatif, Firas A.; Abdullatif, Alaa A.; al-Saffar, Amna

2018-05-01

Hiding technique for dynamic encryption text using encoding table and symmetric encryption method (AES algorithm) is presented in this paper. The encoding table is generated dynamically from MSB of the cover image points that used as the first phase of encryption. The Harris corner point algorithm is applied on cover image to generate the corner points which are used to generate dynamic AES key to second phase of text encryption. The embedded process in the LSB for the image pixels except the Harris corner points for more robust. Experimental results have demonstrated that the proposed scheme have embedding quality, error-free text recovery, and high value in PSNR.

Further evidence that rats rely on local rather than global spatial information to locate a hidden goal: reply to Cheng and Gallistel (2005).

PubMed

McGregor, Anthony; Jones, Peter M; Good, Mark A; Pearce, John M

2006-07-01

Naive male Hooded Lister rats (Rattus norvegicus) were required to find a submerged platform in a right-angled corner between a long and a short wall of a pool in the shape of an irregular pentagon. Tests in a rectangular pool revealed a preference for the corners that corresponded with the correct corner in the pentagon. These findings indicate that rats identified the correct corner in the pentagon by local cues. They contradict the suggestion that rats navigate by moving in a particular direction relative to the principal axis of the shape of their environment.

A corner store intervention in a low-income urban community is associated with increased availability and sales of some healthy foods.

PubMed

Song, Hee-Jung; Gittelsohn, Joel; Kim, Miyong; Suratkar, Sonali; Sharma, Sangita; Anliker, Jean

2009-11-01

While corner store-based nutrition interventions have emerged as a potential strategy to increase healthy food availability in low-income communities, few evaluation studies exist. We present the results of a trial in Baltimore City to increase the availability and sales of healthier food options in local stores. Quasi-experimental study. Corner stores owned by Korean-Americans and supermarkets located in East and West Baltimore. Seven corner stores and two supermarkets in East Baltimore received a 10-month intervention and six corner stores and two supermarkets in West Baltimore served as comparison. During and post-intervention, stocking of healthy foods and weekly reported sales of some promoted foods increased significantly in intervention stores compared with comparison stores. Also, intervention storeowners showed significantly higher self-efficacy for stocking some healthy foods in comparison to West Baltimore storeowners. Findings of the study demonstrated that increases in the stocking and promotion of healthy foods can result in increased sales. Working in small corner stores may be a feasible means of improving the availability of healthy foods and their sales in a low-income urban community.

Corner flow control in high through-flow axial commercial fan/booster using blade 3-D optimization

NASA Astrophysics Data System (ADS)

Zhu, Fang; Jin, Donghai; Gui, Xingmin

2012-02-01

This study is aimed at using blade 3-D optimization to control corner flows in the high through-flow fan/booster of a high bypass ratio commercial turbofan engine. Two kinds of blade 3-D optimization, end-bending and bow, are focused on. On account of the respective operation mode and environment, the approach to 3-D aerodynamic modeling of rotor blades is different from stator vanes. Based on the understanding of the mechanism of the corner flow and the consideration of intensity problem for rotors, this paper uses a variety of blade 3-D optimization approaches, such as loading distribution optimization, perturbation of departure angles and stacking-axis manipulation, which are suitable for rotors and stators respectively. The obtained 3-D blades and vanes can improve the corner flow features by end-bending and bow effects. The results of this study show that flows in corners of the fan/booster, such as the fan hub region, the tip and hub of the vanes of the booster, are very complex and dominated by 3-D effects. The secondary flows there are found to have a strong detrimental effect on the compressor performance. The effects of both end-bending and bow can improve the flow separation in corners, but the specific ways they work and application scope are somewhat different. Redesigning the blades via blade 3-D optimization to control the corner flow has effectively reduced the loss generation and improved the stall margin by a large amount.

High explosive corner turning performance and the LANL mushroom test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, L.G.; Seitz, W.L.; Forest, C.A.

1998-07-01

The Mushroom test is designed to characterize the corner turning performance of a new generation of less sensitive booster explosives. The test is described in detail, and three corner turning figures-of-merit are examined using pure TATB (both Livermore{close_quote}s Ultrafine and a Los Alamos research blend) and PBX9504 as examples. {copyright} {ital 1998 American Institute of Physics.}

On non-symmetric axial corner-layer flow

NASA Astrophysics Data System (ADS)

Boiko, A. V.; Kirilovskiy, S. V.; Nechepurenko, Y. M.; Poplavskaya, T. V.

2017-10-01

The problem of asymmetric incompressible axial flow in a corner formed of two intersecting plates at a right angle is considered. The asymptotic behaviour of the flow far away from the corner is analysed. Two types of asymptotic behaviour are found. It is shown that the flow is very sensitive to the asymmetry parameter. A comparison of the results with computations of full Navier-Stokes equations was performed.

37. GENERAL VIEW OF SLC3W MST STATION 85.5 FROM NORTHEAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

37. GENERAL VIEW OF SLC-3W MST STATION 85.5 FROM NORTHEAST CORNER SHOWING PLATFORM CONTROLS IN SOUTHWEST CORNER, COMMUNICATION STATION AND ELEVATOR ON WEST SIDE. STRETCH SLING CYLINDER PRESSURE GAUGE IN SOUTHWEST CORNER OF STATION 78 VISIBLE THROUGH CENTRAL OPENING. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Full-Scale Experimental Investigation to Quantify Building Component Ignition Vulnerability from Mulch Beds Attacked by Firebrand Showers

PubMed Central

Manzello, Samuel L.; Suzuki, Sayaka; Nii, Daisaku

2015-01-01

Structure ignition by wind-driven firebrand showers is an important fire spread mechanism in large outdoor fires. Experiments were conducted with three common mulch types (shredded hardwood mulch, Japanese Cypress wood chips, and pine bark nuggets) placed adjacent to realistic-scale reentrant corners. In the first series of experiments, mulch beds were placed adjacent to a re-entrant corner constructed with wood studs and lined with oriented strand board (OSB) as the sheathing. The premise behind conducting experiments with no siding treatments applied was predicated on the notion that bare OSB mulch contact would be a worst-case scenario, and therefore, a wall assembly in the most vulnerable state to mulch ignition. In the second series of experiments, vinyl siding was applied to the re-entrant corner assemblies (wood studs/OSB/moisture barrier/vinyl siding), and the influence of vertical separation distance (102 mm or 203 mm) on wall ignition from adjacent mulch beds was determined. The vertical separation distance was maintained by applying gypsum board to the base of the re-entrant corner. The siding itself did not influence the ignition process for the mulch beds, as the mulch beds were the first to ignite from the firebrand showers. In all experiments, it was observed that firebrands produced smoldering ignition in the mulch beds, this transitioned to flaming ignition, and the re-entrant corner assembly was exposed to the flaming mulch beds. With no siding treatments applied, the flaming mulch beds ignited the re-entrant corner, and ignition was observed to propagate to the back side of re-entrant corner assembly under all wind speeds (6 m/s to 8 m/s). With respect to the re-entrant corners fitted with vinyl siding, the mulch type, vertical separation distance, and wind speed were important parameters as to whether flaming ignition was observed to propagate to the back-side of a reentrant corner assembly. Mulches clearly pose an ignition hazard to structures in large outdoor fires. PMID:28184098

Scaling A Moment-Rate Function For Small To Large Magnitude Events

NASA Astrophysics Data System (ADS)

Archuleta, Ralph; Ji, Chen

2017-04-01

Since the 1980's seismologists have recognized that peak ground acceleration (PGA) and peak ground velocity (PGV) scale differently with magnitude for large and moderate earthquakes. In a recent paper (Archuleta and Ji, GRL 2016) we introduced an apparent moment-rate function (aMRF) that accurately predicts the scaling with magnitude of PGA, PGV, PWA (Wood-Anderson Displacement) and the ratio PGA/2πPGV (dominant frequency) for earthquakes 3.3 ≤ M ≤ 5.3. This apparent moment-rate function is controlled by two temporal parameters, tp and td, which are related to the time for the moment-rate function to reach its peak amplitude and the total duration of the earthquake, respectively. These two temporal parameters lead to a Fourier amplitude spectrum (FAS) of displacement that has two corners in between which the spectral amplitudes decay as 1/f, f denotes frequency. At higher or lower frequencies, the FAS of the aMRF looks like a single-corner Aki-Brune omega squared spectrum. However, in the presence of attenuation the higher corner is almost certainly masked. Attempting to correct the spectrum to an Aki-Brune omega-squared spectrum will produce an "apparent" corner frequency that falls between the double corner frequency of the aMRF. We reason that the two corners of the aMRF are the reason that seismologists deduce a stress drop (e.g., Allmann and Shearer, JGR 2009) that is generally much smaller than the stress parameter used to produce ground motions from stochastic simulations (e.g., Boore, 2003 Pageoph.). The presence of two corners for the smaller magnitude earthquakes leads to several questions. Can deconvolution be successfully used to determine scaling from small to large earthquakes? Equivalently will large earthquakes have a double corner? If large earthquakes are the sum of many smaller magnitude earthquakes, what should the displacement FAS look like for a large magnitude earthquake? Can a combination of such a double-corner spectrum and random vibration theory explain the PGA, PGV scaling relationships for larger magnitude?

Yield surface evolution for columnar ice

NASA Astrophysics Data System (ADS)

Zhou, Zhiwei; Ma, Wei; Zhang, Shujuan; Mu, Yanhu; Zhao, Shunpin; Li, Guoyu

A series of triaxial compression tests, which has capable of measuring the volumetric strain of the sample, were conducted on columnar ice. A new testing approach of probing the experimental yield surface was performed from a single sample in order to investigate yield and hardening behaviors of the columnar ice under complex stress states. Based on the characteristic of the volumetric strain, a new method of defined the multiaxial yield strengths of the columnar ice is proposed. The experimental yield surface remains elliptical shape in the stress space of effective stress versus mean stress. The effect of temperature, loading rate and loading path in the initial yield surface and deformation properties of the columnar ice were also studied. Subsequent yield surfaces of the columnar ice have been explored by using uniaxial and hydrostatic paths. The evolution of the subsequent yield surface exhibits significant path-dependent characteristics. The multiaxial hardening law of the columnar ice was established experimentally. A phenomenological yield criterion was presented for multiaxial yield and hardening behaviors of the columnar ice. The comparisons between the theoretical and measured results indicate that this current model is capable of giving a reasonable prediction for the multiaxial yield and post-yield properties of the columnar ice subjected to different temperature, loading rate and path conditions.

Centroid stabilization for laser alignment to corner cubes: designing a matched filter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Awwal, Abdul A. S.; Bliss, Erlan; Brunton, Gordon

2016-11-08

Automation of image-based alignment of National Ignition Facility high energy laser beams is providing the capability of executing multiple target shots per day. One important alignment is beam centration through the second and third harmonic generating crystals in the final optics assembly (FOA), which employs two retroreflecting corner cubes as centering references for each beam. Beam-to-beam variations and systematic beam changes over time in the FOA corner cube images can lead to a reduction in accuracy as well as increased convergence durations for the template-based position detector. A systematic approach is described that maintains FOA corner cube templates and guaranteesmore » stable position estimation.« less

Centroid stabilization for laser alignment to corner cubes: designing a matched filter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Awwal, Abdul A. S.; Bliss, Erlan; Brunton, Gordon

2016-11-08

Automation of image-based alignment of NIF high energy laser beams is providing the capability of executing multiple target shots per day. One important alignment is beam centration through the second and third harmonic generating crystals in the final optics assembly (FOA), which employs two retro-reflecting corner cubes as centering references for each beam. Beam-to-beam variations and systematic beam changes over time in the FOA corner cube images can lead to a reduction in accuracy as well as increased convergence durations for the template-based position detector. A systematic approach is described that maintains FOA corner cube templates and guarantees stable positionmore » estimation.« less

Picometer Level Modeling of a Shared Vertex Double Corner Cube in the Space Interferometry Mission Kite Testbed

NASA Technical Reports Server (NTRS)

Kuan, Gary M.; Dekens, Frank G.

2006-01-01

The Space Interferometry Mission (SIM) is a microarcsecond interferometric space telescope that requires picometer level precision measurements of its truss and interferometer baselines. Single-gauge metrology errors due to non-ideal physical characteristics of corner cubes reduce the angular measurement capability of the science instrument. Specifically, the non-common vertex error (NCVE) of a shared vertex, double corner cube introduces micrometer level single-gauge errors in addition to errors due to dihedral angles and reflection phase shifts. A modified SIM Kite Testbed containing an articulating double corner cube is modeled and the results are compared to the experimental testbed data. The results confirm modeling capability and viability of calibration techniques.

Surface topography of two trematodes parasites infecting grey heron Ardea cinerea Jouyi (Aves, Ciconiiformes) in Qena, Egypt.

PubMed

Ammar, Khalaf Nour Abd El-Wahed

2015-04-01

Apharyngostrigea ardeolina and Echinoparyphium recurvatum are two important digenean parasites that were recovered from small intestine of grey heron with an infection rate (16.2%) and (8.8%) respectively. The surface topography of two species was redescribed by both light and scanning electron microscopy. Using SEM studies showed that the body surface of two trematodes were covered by contact receptors, several types of sensory tegumental papillae which may have useful function in orientation and feeding through increasing the surface area of absorption, could also play a role in sensation or in selection of the materials for ingestion by the fluke. The head collar of E. recurvatum is reniform in shape, bearing uninterrupted double row of 41 collar finger-like spines, a total including 4 end group ones on both ventral corners., tegumental spines were tongue-shaped without a terminal tip.

A finite-element analysis for steady and oscillatory subsonic flow around complex configurations

NASA Technical Reports Server (NTRS)

Chen, L. T.; Suciu, E. O.; Morino, L.

1974-01-01

The problem of potential subsonic flow around complex configurations is considered. The solution is given of an integral equation relating the values of the potential on the surface of the body to the values of the normal derivative, which is known from the boundary conditions. The surface of the body is divided into small (hyperboloidal quadrilateral) surface elements, which are described in terms of the Cartesian components of the four corner points. The values of the potential (and its normal derivative) within each element is assumed to be constant and equal to its value at the centroid of the element. The coefficients of the equation are given by source and doublet integrals over the surface elements. Closed form evaluations of the integrals are presented. The results obtained with the above formulation are compared with existing analytical and experimental results.

A Study of Supersonic Compression-Corner Interactions using Hybrid LES/RANS Models

DTIC Science & Technology

2014-01-20

Mach 2.5 shock / boundary layer interaction in a wind tunnel (experiments conducted at Cambridge University [15]) as a means of assessing methods... wind tunnel . The shock impinges upon the bottom surface of the wind tunnel , creating a region of shock -separated flow. The structure of the SBLI... waves into a shock wave (Figure 19, X = 0.1016 and X = 0.1278 stations) are also not well-predicted. The hot-wire measurements may not be as

Safety Grooving

NASA Technical Reports Server (NTRS)

1985-01-01

Safety grooving, the cutting of grooves in concrete to increase traction and prevent injury, was first developed to reduce aircraft accidents on wet runways. Represented by the International Grooving and Grinding Association (IG&GA), the industry expanded into highway and pedestrian applications. The technique originated at Langley, which assisted in testing the grooving at airports and on highways. Skidding was reduced, stopping distance decreased, and a vehicle's cornering ability on curves was increased. The process has been extended to animal holding pens, steps, parking lots and other potentially slippery surfaces.

Enhanced backscatter of optical beams reflected in turbulent air

NASA Astrophysics Data System (ADS)

Nelson, W.; Palastro, J. P.; Wu, C.; Davis, C. C.

2015-07-01

Optical beams propagating through air acquire phase distortions from turbulent fluctuations in the refractive index. While these distortions are usually deleterious to propagation, beams reflected in a turbulent medium can undergo a local recovery of spatial coherence and intensity enhancement referred to as enhanced backscatter (EBS). Using a combination of lab-scale experiments and simulations, we investigate the EBS of optical beams reflected from corner cubes and rough surfaces, and identify the regimes in which EBS is most distinctly observed.

STS-37 Gamma Ray Observatory (GRO) grappled by RMS

NASA Image and Video Library

1991-04-07

Backdropped against the Earth's surface, the Gamma Ray Observatory (GRO) with its solar array (SA) panels deployed is grappled by the remote manipulator system (RMS) during STS-37 systems checkout. GRO's four complement instruments are visible: the Energetic Gamma Ray Experiment Telescope (EGRET) (at the bottom); the Imaging Compton Telescope (COMPTEL) (center); the Oriented Scintillation Spectrometer Experiment (OSSE) (top); and Burst and Transient Source Experiment (BATSE) (on four corners). The view was taken by STS-37 crew through an aft flight deck overhead window.

Delayed diagnosis of an isolated posterolateral corner injury: a case report

PubMed Central

Welsh, Patrick; DeGraauw, Christopher; Whitty, David

2016-01-01

Introduction: Isolated injuries to the posterolateral corner of the knee are a rare and commonly missed injury associated with athletic trauma, motor vehicle accidents, and falls. Delayed or missed diagnoses can negatively impact patient prognosis, contributing to residual instability, chronic pain, and failure of surgical repair to other ligaments. Case Presentation: A 44-year-old male CrossFit athlete presented with a history of two non-contact hyperextension injuries to his left knee while walking on ice. The only positive finding was the Dial Test at 30 degrees of knee flexion, indicative of an isolated posterolateral corner injury. After a delay in diagnosis, the patient underwent a reconstruction of the posterolateral corner and subsequent rehabilitation. Early recognition of this injury is important as this can affect the prognosis and activities of daily living of the patient. Summary: This case will discuss the clinical presentation, diagnostic procedures, and management of an isolated posterolateral corner injury and highlight the importance of early recognition and referrals from primary contact healthcare practitioners. PMID:28065990

An accurate real-time model of maglev planar motor based on compound Simpson numerical integration

NASA Astrophysics Data System (ADS)

Kou, Baoquan; Xing, Feng; Zhang, Lu; Zhou, Yiheng; Liu, Jiaqi

2017-05-01

To realize the high-speed and precise control of the maglev planar motor, a more accurate real-time electromagnetic model, which considers the influence of the coil corners, is proposed in this paper. Three coordinate systems for the stator, mover and corner coil are established. The coil is divided into two segments, the straight coil segment and the corner coil segment, in order to obtain a complete electromagnetic model. When only take the first harmonic of the flux density distribution of a Halbach magnet array into account, the integration method can be carried out towards the two segments according to Lorenz force law. The force and torque analysis formula of the straight coil segment can be derived directly from Newton-Leibniz formula, however, this is not applicable to the corner coil segment. Therefore, Compound Simpson numerical integration method is proposed in this paper to solve the corner segment. With the validation of simulation and experiment, the proposed model has high accuracy and can realize practical application easily.

Numerical solutions of the Navier-Stokes equations for the supersonic laminar flow over a two-dimensional compression corner

NASA Technical Reports Server (NTRS)

Carter, J. E.

1972-01-01

Numerical solutions have been obtained for the supersonic, laminar flow over a two-dimensional compression corner. These solutions were obtained as steady-state solutions to the unsteady Navier-Stokes equations using the finite difference method of Brailovskaya, which has second-order accuracy in the spatial coordinates. Good agreement was obtained between the computed results and wall pressure distributions measured experimentally for Mach numbers of 4 and 6.06, and respective Reynolds numbers, based on free-stream conditions and the distance from the leading edge to the corner. In those calculations, as well as in others, sufficient resolution was obtained to show the streamline pattern in the separation bubble. Upstream boundary conditions to the compression corner flow were provided by numerically solving the unsteady Navier-Stokes equations for the flat plate flow field, beginning at the leading edge. The compression corner flow field was enclosed by a computational boundary with the unknown boundary conditions supplied by extrapolation from internally computed points.

Delayed diagnosis of an isolated posterolateral corner injury: a case report.

PubMed

Welsh, Patrick; DeGraauw, Christopher; Whitty, David

2016-12-01

Isolated injuries to the posterolateral corner of the knee are a rare and commonly missed injury associated with athletic trauma, motor vehicle accidents, and falls. Delayed or missed diagnoses can negatively impact patient prognosis, contributing to residual instability, chronic pain, and failure of surgical repair to other ligaments. A 44-year-old male CrossFit athlete presented with a history of two non-contact hyperextension injuries to his left knee while walking on ice. The only positive finding was the Dial Test at 30 degrees of knee flexion, indicative of an isolated posterolateral corner injury. After a delay in diagnosis, the patient underwent a reconstruction of the posterolateral corner and subsequent rehabilitation. Early recognition of this injury is important as this can affect the prognosis and activities of daily living of the patient. This case will discuss the clinical presentation, diagnostic procedures, and management of an isolated posterolateral corner injury and highlight the importance of early recognition and referrals from primary contact healthcare practitioners.

Stability of Capillary Surfaces in Rectangular Containers: The Right Square Cylinder

NASA Technical Reports Server (NTRS)

Weislogel, M. M.; Hsieh, K. C.

1998-01-01

The linearized governing equations for an ideal fluid are presented for numerical analysis for the stability of free capillary surfaces in rectangular containers against unfavorable disturbances (accelerations,i.e. Rayleigh-Taylor instability). The equations are solved for the case of the right square cylinder. The results are expressed graphically in term of a critical Bond number as a function of system contact angle. A critical wetting phenomena in the corners is shown to significantly alter the region of stability for such containers in contrast to simpler geometries such as the right circular cylinder or the infinite rectangular slot. Such computational results provide additional constraints for the design of fluids systems for space-based applications.

The Science, Engineering and Technology Career Library Corner. Final report, February 1, 1995--January 31, 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cole, P.R.

1996-03-01

A grant was made to install and pilot-test the Science, Engineering and Technology (SET) Career Library Corner at the New York Hall of Science. The SET Career Library Corner is located in a multi-media library setting where visitors can explore careers in a quiet, uninterrupted environment, in contrast to the original installation designed as a museum floor exhibit.

Laws of trigonometry on SU(3)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aslaksen, H.

1988-01-01

In this paper we will study triangles in SU(3). The orbit space of congruence classes of triangles in SU(3) has dimension 8. Each corner is made up of a pair of tangent vectors (X,Y), and we consider the 8 functions trX{sup 2}, i trX{sup 3}, trY{sup 2}, i trY{sup 3}, trXY, i trY{sup 2}Y, i trXY{sup 2}, trX{sup 2}Y{sup 2} which are invariant under the full isometry group of SU(3). We show that these 8 corner invariants determine the isometry class of the triangle. We give relations (laws of trigonometry) between the invariants at the different corners, enabling us tomore » determine the invariants at the remaining corners, including the values of the remaining side and angles, if we know one set of corner invariants. The invariants that only depend on one tangent vector we will call side invariants, while those that depend on two tangent vectors will be called angular invariants. For each triangle we then have 6 side invariants and 12 angular invariants. Hence we need 18 {minus} 8 = 10 laws of trigonometry. The basic tool for deriving these laws is a formula expressing tr(exp X exp Y) in terms of the corner invariants.« less

Development and Implementation: B’More Healthy Communities for Kid’s Store and Wholesaler Intervention

PubMed Central

Schwendler, Teresa; Shipley, Cara; Budd, Nadine; Trude, Angela; Surkan, Pamela J.; Steeves, Elizabeth Anderson; de Morais Sato, Priscila; Eckmann, Thomas; Loh, Hong; Gittelsohn, Joel

2017-01-01

Higher rates of obesity and obesity-related chronic disease are prevalent in communities where there is limited access to affordable, healthy food. The B’More Healthy Communities for Kids (BHCK) trial worked at multiple levels of the food environment including food wholesalers and corner stores to improve the surrounding community’s access to healthy food. The objective of this article is to describe the development and implementation of BHCK’s corner store and wholesaler interventions through formal process evaluation. Researchers evaluated each level of the intervention to assess reach, dose delivered, and fidelity. Corner store and wholesaler reach, dose delivered, and fidelity were measured by number of interactions, promotional materials distributed, and maintenance of study materials, respectively. Overall, the corner store implementation showed moderate reach, dose delivered, and high fidelity. The wholesaler intervention was implemented with high reach, dose, and fidelity. The program held 355 corner store interactive sessions and had 9,347 community member interactions, 21% of which were with children between the ages of 10 and 14 years. There was a 15% increase in corner store promoted food stocking during Wave 1 and a 17% increase during Wave 2. These findings demonstrate a successfully implemented food retailer intervention in a low-income urban setting. PMID:28343413

Changes in food and beverage environments after an urban corner store intervention.

PubMed

Cavanaugh, Erica; Green, Sarah; Mallya, Giridhar; Tierney, Ann; Brensinger, Colleen; Glanz, Karen

2014-08-01

In response to the obesity epidemic, interventions to improve the food environment in corner stores have gained attention. This study evaluated the availability, quality, and price of foods in Philadelphia corner stores before and after a healthy corner store intervention with two levels of intervention intensity ("basic" and "conversion"). Observational measures of the food environment were completed in 2011 and again in 2012 in corner stores participating in the intervention, using the Nutrition Environment Measures Survey for Corner Stores (NEMS-CS). Main analyses included the 211 stores evaluated at both time-points. A time-by-treatment interaction analysis was used to evaluate the changes in NEMS-CS scores by intervention level over time. Availability of fresh fruit increased significantly in conversion stores over time. Specifically, there were significant increases in the availability of apples, oranges, grapes, and broccoli in conversion stores over time. Conversion stores showed a trend toward a significantly larger increase in the availability score compared to basic stores over time. Interventions aimed at increasing healthy food availability are associated with improvements in the availability of low-fat milk, fruits, and some vegetables, especially when infrastructure changes, such as refrigeration and shelving enhancements, are offered. Copyright © 2014 Elsevier Inc. All rights reserved.

Baseline ambient gaseous ammonia concentrations in the Four Corners area and eastern Oklahoma, USA.

PubMed

Sather, Mark E; Mathew, Johnson; Nguyen, Nghia; Lay, John; Golod, George; Vet, Robert; Cotie, Joseph; Hertel, Terry; Aaboe, Erik; Callison, Ryan; Adam, Jacque; Keese, Danielle; Freise, Jeremy; Hathcoat, April; Sakizzie, Brenda; King, Michael; Lee, Chris; Oliva, Sylvia; San Miguel, George; Crow, Leon; Geasland, Frank

2008-11-01

Ambient ammonia monitoring using Ogawa passive samplers was conducted in the Four Corners area and eastern Oklahoma, USA during 2007. The resulting data will be useful in the multipollutant management of ozone, nitrogen oxides, and visibility (atmospheric regional haze) in the Four Corners area, an area with growing oil/gas production and increasing coal-based power plant construction. The passive monitoring data also add new ambient ammonia concentration information for the U.S. and will be useful to scientists involved in present and future visibility modeling exercises. Three week integrated passive ammonia samples were taken at five sites in the Four Corners area and two sites in eastern Oklahoma from December, 2006 through December, 2007 (January, 2008 for two sites). Results show significantly higher regional background ammonia concentrations in eastern Oklahoma (1.8 parts per billion (ppb) arithmetic mean) compared to the Four Corners area (0.2 ppb arithmetic mean). Annual mean ammonia concentrations for all Four Corners area sites for the 2007 study ranged from 0.2 ppb to 1.5 ppb. Peak ambient ammonia concentrations occurred in the spring and summer in both areas. The passive samplers deployed at the Stilwell, Oklahoma site compared favorably with other passive samplers and a continuous ammonia monitoring instrument.

Precipitation variability in the Four Corners region USA from 2002 to 2015

NASA Astrophysics Data System (ADS)

Tulley-Cordova, C. L.; Bowen, G. J.; Brady, I.; Bekis, J.

2016-12-01

Due to the arid climate, the Navajo Nation situated in the southwestern United States (US) is sensitive to small changes in precipitation. The Navajo Nation is the largest land based tribe in the US; Navajo residents, wildlife, livestock, and vegetation are highly dependent on water resources including precipitation, surface, ground, and spring waters for vitality. Changes in precipitation directly impacts the Navajo Nation's ecosystem including a variety of interconnected effects such as ground water recharge, frequency of dust migration and strength of winds, flow in ephemeral and perennial streams, plant and animal populations, wildfires, change in vegetative cover and possible alterations in species composition. This study examines hydroclimatic changes during months, seasons, and water years across the Navajo Nation from 2002 to 2015 and how Four Corners USA precipitation variability and trends compares to large-scale atmospheric circulation patterns. Examination of spatial and temporal trends of precipitation variability during this time period can be used to assist an area with limited water management infrastructure with future water planning and help understand a region that has been poorly studied in the past.

Etch Profile Simulation Using Level Set Methods

NASA Technical Reports Server (NTRS)

Hwang, Helen H.; Meyyappan, Meyya; Arnold, James O. (Technical Monitor)

1997-01-01

Etching and deposition of materials are critical steps in semiconductor processing for device manufacturing. Both etching and deposition may have isotropic and anisotropic components, due to directional sputtering and redeposition of materials, for example. Previous attempts at modeling profile evolution have used so-called "string theory" to simulate the moving solid-gas interface between the semiconductor and the plasma. One complication of this method is that extensive de-looping schemes are required at the profile corners. We will present a 2D profile evolution simulation using level set theory to model the surface. (1) By embedding the location of the interface in a field variable, the need for de-looping schemes is eliminated and profile corners are more accurately modeled. This level set profile evolution model will calculate both isotropic and anisotropic etch and deposition rates of a substrate in low pressure (10s mTorr) plasmas, considering the incident ion energy angular distribution functions and neutral fluxes. We will present etching profiles of Si substrates in Ar/Cl2 discharges for various incident ion energies and trench geometries.

Revisiting Turbulence Model Validation for High-Mach Number Axisymmetric Compression Corner Flows

NASA Technical Reports Server (NTRS)

Georgiadis, Nicholas J.; Rumsey, Christopher L.; Huang, George P.

2015-01-01

Two axisymmetric shock-wave/boundary-layer interaction (SWBLI) cases are used to benchmark one- and two-equation Reynolds-averaged Navier-Stokes (RANS) turbulence models. This validation exercise was executed in the philosophy of the NASA Turbulence Modeling Resource and the AIAA Turbulence Model Benchmarking Working Group. Both SWBLI cases are from the experiments of Kussoy and Horstman for axisymmetric compression corner geometries with SWBLI inducing flares of 20 and 30 degrees, respectively. The freestream Mach number was approximately 7. The RANS closures examined are the Spalart-Allmaras one-equation model and the Menter family of kappa - omega two equation models including the Baseline and Shear Stress Transport formulations. The Wind-US and CFL3D RANS solvers are employed to simulate the SWBLI cases. Comparisons of RANS solutions to experimental data are made for a boundary layer survey plane just upstream of the SWBLI region. In the SWBLI region, comparisons of surface pressure and heat transfer are made. The effects of inflow modeling strategy, grid resolution, grid orthogonality, turbulent Prandtl number, and code-to-code variations are also addressed.

The food environment and student weight status, Los Angeles County, 2008-2009.

PubMed

Langellier, Brent A

2012-01-01

One factor believed to affect overweight status is the food environment, or the distribution of outlets that serve healthful or unhealthful foods in residential areas, workplaces, and schools. Few studies have investigated the association between the food environment and the prevalence of overweight among children and adolescents. The objective of this study was to investigate the association between the distribution of corner stores and fast food restaurants around Los Angeles County public schools and the prevalence of overweight among students. Hierarchical linear models were used to assess the association between the presence of corner stores or fast food restaurants within a half-mile of Los Angeles County schools (N = 1,694) and overweight prevalence among students in grades 5, 7, and 9. The presence of corner stores and fast food restaurants varied significantly by schools' racial/ethnic composition, Title 1 eligibility, and rural/suburban vs urban location. After adjustment for other factors, overweight prevalence was 1.6 percentage points higher at majority-Latino schools that had at least 1 corner store within a half-mile than at majority-Latino schools that did not have a corner store within a half-mile. The association between corner stores and overweight prevalence varied significantly between majority-Latino schools and schools that were majority-white or that had no racial/ethnic majority. The presence of fast food restaurants within a half-mile of schools was not associated with overweight prevalence among students. This study underscores the importance of interventions that seek to improve the healthfulness of corner store inventories and of student purchases.

Improved Mirror Source Method in Roomacoustics

NASA Astrophysics Data System (ADS)

Mechel, F. P.

2002-10-01

Most authors in room acoustics qualify the mirror source method (MS-method) as the only exact method to evaluate sound fields in auditoria. But evidently nobody applies it. The reason for this discrepancy is the abundantly high numbers of needed mirror sources which are reported in the literature, although such estimations of needed numbers of mirror sources mostly are used for the justification of more or less heuristic modifications of the MS-method. The present, intentionally tutorial article accentuates the analytical foundations of the MS-method whereby the number of needed mirror sources is reduced already. Further, the task of field evaluation in three-dimensional spaces is reduced to a sequence of tasks in two-dimensional room edges. This not only allows the use of easier geometrical computations in two dimensions, but also the sound field in corner areas can be represented by a single (directional) source sitting on the corner line, so that only this "corner source" must be mirror-reflected in the further process. This procedure gives a drastic reduction of the number of needed equivalent sources. Finally, the traditional MS-method is not applicable in rooms with convex corners (the angle between the corner flanks, measured on the room side, exceeds 180°). In such cases, the MS-method is combined below with the second principle of superposition(PSP). It reduces the scattering task at convex corners to two sub-tasks between one flank and the median plane of the room wedge, i.e., always in concave corner areas where the MS-method can be applied.

The effect of retrosplenial cortex lesions in rats on incidental and active spatial learning

PubMed Central

Nelson, A. J. D.; Hindley, E. L.; Pearce, J. M.; Vann, S. D.; Aggleton, J. P.

2015-01-01

The study examined the importance of the retrosplenial cortex for the incidental learning of the spatial arrangement of distinctive features within a scene. In a modified Morris water-maze, rats spontaneously learnt the location of an escape platform prior to swimming to that location. For this, rats were repeatedly placed on a submerged platform in one corner of either a rectangular (Experiment 1) or square (Experiments 2, 3) pool with walls of different appearance. The rats were then released in the center of the pool for their first test trial. In Experiment 1, the correct corner and its diagonally opposite partner (also correct) were specified by the geometric properties of the pool. Rats with retrosplenial lesions took longer to first reach a correct corner, subsequently showing an attenuated preference for the correct corners. A reduced preference for the correct corner was also found in Experiment 2, when platform location was determined by the juxtaposition of highly salient visual cues (black vs. white walls). In Experiment 3, less salient visual cues (striped vs. white walls) led to a robust lesion impairment, as the retrosplenial lesioned rats showed no preference for the correct corner. When subsequently trained actively to swim to the correct corner over successive trials, retrosplenial lesions spared performance on all three discriminations. The findings not only reveal the importance of the retrosplenial cortex for processing various classes of visuospatial information but also highlight a broader role in the incidental learning of the features of a spatial array, consistent with the translation of scene information. PMID:25705182

Forest conditions in the Gila River Forest Reserve, New Mexico

USGS Publications Warehouse

Rixon, T.F.

1905-01-01

The Gila River Forest Reserve was established by proclamation of President McKinley on March 2, 1899. The following is a statement of the boundaries as laid down in the proclamation: "Beginning at a point on the boundary line between New Mexico and Arizona, where it is intersected by the north line of township five (5) south, range twenty-one (21) west, New Mexico principle meridian, New Mexico; thence easterly along the township line to the northeast corner of township five (5) south, range sixteen (16) west; thence southerly along the range line between ranges fifteen (15) and sixteen (16) west, to the southeast corner of township eight (8) south, range sixteen (16) west; thence easterly along the township line to the northeast corner of township nine (9) south, range fifteen (15) west; thence southerly along the range line to the southeast corner of said township; thence easterly along the township line to the northeast corner of township ten (10) south, range ten (10) west; thence southerly along the first guide meridian west, between ranges nine (9) and ten (10) west, to its intersection with the third (3rd) standard parallel south, between townships fifteen (15) and sixteen (16) south; thence westerly along the said third (3rd) standard parallel south to the southwest corner of township fifteen (15) south, range sixteen (16) west; thence northerly along the range line to the northwest corner of said township; thence westerly along the township line to the northeast corner of township fifteen (15) south, range nineteen (19) west; thence southerly along the range line to its intersection with the third (3d) standard parallel south; thence westerly along the third (3rd) standard parallel south to its intersection with the boundary line between New Mexico and Arizona; thence northerly along said boundary line to the point where it intersects the north line of township five (5) south, range twenty-one (21) west, the place of beginning."

A comparison of the interaction of nitric oxide with the heteropolytungstic acids H{sub 3}PW{sub 12}O{sub 40}, H{sub 0.5}Cs{sub 2.5}PW{sub 12}O{sub 40}, HMgPW{sub 12}O{sub 40}, H{sub 8}SiW{sub 11}O{sub 38}, H{sub 4}SiW{sub 12}O{sub 40}, and H{sub 10}CoW{sub 12}O{sub 42}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herring, A.M.; McCormick, R.L.; Boonrueng, S.R.

2000-05-18

The interaction between NO and the heteropolytungstic acids (HPAs) H{sub 3}PW{sub 12}O{sub 40} (HPW), H{sub 0.5}Cs{sub 2.5}PW{sub 12}O{sub 40} (HCsPW), HMgPW{sub 12}O{sub 40} (HMgPW), H{sub 8}SiW{sub 11}O{sub 38} (HSiW{sub 11}), H{sub 4}SiW{sub 12}O{sub 40} (HSiW), and H{sub 10}CoW{sub 12}{sub 42}(HCoW) in the presence of O{sub 2}(g) was investigated. The tools employed were in situ diffuse reflectance infrared spectroscopy, X-ray powder diffraction, and solid-state {sup 1}H NMR. It was determined that protons may either be present in the HPAs secondary structure as anhydrous protons or be bound to one or two water molecules as H{sub 3}O{sup +} or H{sub 5}O{sub 2}{supmore » +}, respectively. A previous investigation found that HPW sorbed NO into its bulk structure as NOH{sup +}, whereas the anhydrous potassium salt of HPW exhibited weak chemisorption of NO on its surface. In the present study, it was found that NO chemisorbed weakly on the surface of the anhydrous HCsPW. For HMgPW and HSiW, IR and NMR evidence suggests that water is present as H{sub 3}O{sup +}, and the formation of surface-bound NOH{sup +} was observed. Inclusion of NO into the secondary structure as NOH{sup +} was observed for HPW, HSiW{sub 11}, and HCoW. Literature data for HPW, as well as IR and NMR results reported here, indicate that these HPAs contain water as H{sub 5}O{sub 2}{sup +}. The presence of H{sub 5}O{sub 2}{sup +} is, therefore, a prerequisite for NO incorporation as NOH{sup +} in the HPA secondary structure. These HPAs exhibited two modes of NO bonding in the secondary structure: a strongly hydrogen-bound hydrated form, NOH{sup +}{center_dot}H{sub 2}O, and a more weakly bound anhydrous form, NOH{sup +}. Evidence suggests that it is the hydrated form that decomposes, yielding N{sub 2} upon rapid heating. Both NO-containing species interact with terminal and corner-sharing oxygen atoms of the Keggin ion. Anions that are held apart by terminal oxygen-hydrogen bonds have a larger lattice parameter than those held apart by terminal oxygen-hydrogen and corner-sharing oxygen-nitrogen bonds. The lattice contraction upon NO incorporation implies activation of NO by an intimate interaction with oxygen of the Keggin anion.« less

Surface sampling techniques for 3D object inspection

NASA Astrophysics Data System (ADS)

Shih, Chihhsiong S.; Gerhardt, Lester A.

1995-03-01

While the uniform sampling method is quite popular for pointwise measurement of manufactured parts, this paper proposes three novel sampling strategies which emphasize 3D non-uniform inspection capability. They are: (a) the adaptive sampling, (b) the local adjustment sampling, and (c) the finite element centroid sampling techniques. The adaptive sampling strategy is based on a recursive surface subdivision process. Two different approaches are described for this adaptive sampling strategy. One uses triangle patches while the other uses rectangle patches. Several real world objects were tested using these two algorithms. Preliminary results show that sample points are distributed more closely around edges, corners, and vertices as desired for many classes of objects. Adaptive sampling using triangle patches is shown to generally perform better than both uniform and adaptive sampling using rectangle patches. The local adjustment sampling strategy uses a set of predefined starting points and then finds the local optimum position of each nodal point. This method approximates the object by moving the points toward object edges and corners. In a hybrid approach, uniform points sets and non-uniform points sets, first preprocessed by the adaptive sampling algorithm on a real world object were then tested using the local adjustment sampling method. The results show that the initial point sets when preprocessed by adaptive sampling using triangle patches, are moved the least amount of distance by the subsequently applied local adjustment method, again showing the superiority of this method. The finite element sampling technique samples the centroids of the surface triangle meshes produced from the finite element method. The performance of this algorithm was compared to that of the adaptive sampling using triangular patches. The adaptive sampling with triangular patches was once again shown to be better on different classes of objects.

Constraining the location of the Archean--Proterozoic suture in the Great Basin based on magnetotelluric soundings

USGS Publications Warehouse

Rodriguez, Brian D.; Sampson, Jay A.

2012-01-01

It is important to understand whether major mining districts in north-central Nevada are underlain by Archean crust, known to contain major orogenic gold deposits, or, alternatively, by accreted crust of the Paleoproterozoic Mojave province. Determining the location and orientation of the Archean-Proterozoic suture zone between the Archean crust and Mojave province is also critical because it may influence subsequent patterns of sedimentation, deformation, magmatism, and hydrothermal activity. In the Great Basin, the attitude of the suture zone is unknown because it is concealed below cover. A regional magnetotelluric sounding profile along the Utah-Nevada State line reveals a deeply penetrating, broad electrical conductor that may be the Archean-Proterozoic suture zone in the northwest corner of Utah. This major crustal conductor's strike direction is northwest, where it broadens to about 80 km wide below about 3-km depth. These results suggest that the southwestern limit of intact Archean crust in this part of the Great Basin is farther north than previously reported. These results also suggest that the major gold belts in north-central Nevada are located over the Paleoproterozoic Mojave province, and the Archean terrain lies northeast in the northwest corner of Utah. Rifted Archean crust segments south and west of the suture suggest that future mineral exploration northeast of current mineral trends may yield additional gold deposits.

Fracture Decoupling of Small Chemical Explosions in Granite and Limestone

NASA Astrophysics Data System (ADS)

Stroujkova, A. F.; Bonner, J. L.; Reinke, R.; Lenox, E. A.

2012-12-01

Reduction of the seismic amplitudes produced by underground explosions due to dissipation in a low-coupling medium poses a significant challenge for nuclear test monitoring. We examined the data from two experiments, which involved conducting explosions in the damage zone created by previous explosions ("repeat shots"). The first experiment was conducted in central New Hampshire in a fluid saturated granodiorite. The experiment involved detonating two 46 kg explosions: one in virgin rock and the other in the fractured rock zone produced by a larger (232 kg) explosion. The second experiment took place near Albuquerque, NM, in dry limestone. In this scenario the second explosion was conducted in the cavity created by the first explosion. Both limestone explosions had yields of 90.5 kg. The reduction of the seismic amplitudes was observed for both repeat shots: in granodiorite the amplitudes were reduced by a factor of 2-3, in limestone by a factor of 3-4 compared to the shots in the undamaged rocks. For the granodiorite repeat shot the decoupling ratios were frequency dependent with stronger amplitude reduction at higher frequencies. In addition, the virgin rock shot produced higher corner frequency and overshoot parameter than the repeat shot. For the limestone shot the decoupling ratios were nearly flat at all frequencies with similar corner frequencies. This observation suggests different mechanisms of energy dissipation for the two experiments.

Studies of Itokawa's Surface Exposure by Measurements of Cosmic-ray Produced Nuclides

NASA Technical Reports Server (NTRS)

Caffee, M. W.; Nishiizumi, K.; Tsuchiyama, A.; Uesugi, M.; Zolensky, M. E.

2014-01-01

We plan to investigate the evolutionary history of surface materials from 25143 Itokawa, the Hayabusa samples. Our studies are based on the measurement of nuclides produced in asteroidal surface materials by cosmic rays. Cosmogenic radionuclides are used to determine the duration and nature of the exposure of materials to energetic particles. Our goals are to understand both the fundamental processes on the asteroidal surface and the evolutionary history of its surface materials. They are also key to understanding the history of Itokawa's surface and asteroid-meteoroid evolutionary dynamics. To achieve our key goals, in particular reconstructing the evolutionary histories of the asteroidal surface, we proposed: (1) characterizing Itokawa particles using SXCT, SXRD, and FE-SEM without modification of the sample; (2) embedding each particle in acrylic resin, then slicing a small corner with an ultra-microtome and examining it using super-STEM and SIMS for characterizing surface morphology, space weathering, and oxygen three-isotope analysis; and finally (3) measuring small amounts of cosmogenic radionuclides (104-105 atoms) in Hayabusa samples by AMS. However, we have to modify our plan due to unexpected situation.

Searching for the corner seismic moment in worldwide data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Felgueiras, Miguel; Santos, Rui; Martins, João Paulo

2015-12-31

In this paper the existence of the corner frequency value for the seismic moment distribution is investigated, analysing worldwide data. Pareto based distributions, usually considered as the most suitable to this type of data, are fitted to the most recent data, available in a global earthquake catalog. Despite the undeniable finite nature of the seismic moment data, we conclude that no corner frequency can be established considering the available data set.

The posterolateral corner of the knee.

PubMed

Vinson, Emily N; Major, Nancy M; Helms, Clyde A

2008-02-01

The purpose of this article is to review the clinical importance and MRI appearances of injuries to the posterolateral corner of the knee. Injuries to the posterolateral corner structures of the knee can cause significant disability due to instability, cartilage degeneration, and cruciate graft failure. Becoming familiar with the anatomy of this region can improve one's ability to detect subtle abnormalities and can perhaps lead to improvements in diagnosing and understanding injuries to this area.

31. VIEW OF DRILL HALL FROM NORTH END OF DRILL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. VIEW OF DRILL HALL FROM NORTH END OF DRILL FLOOR FACING SOUTH. SHOWS EAST AND WEST BALCONIES, VEHICLE ENTRANCE AT THE SOUTHWEST CORNER OF THE DRILL FLOOR, THE CONCESSION STAND IN THE SOUTHEAST CORNER OF THE DRILL FLOOR AND THE FOUR WINDOWS IN THE SOUTH TRUSS SPACE. NOTE CRACKS IN THE UPPER RIGHT CORNER (WEST) OF THE SOUTH WALL. - Yakima National Guard Armory, 202 South Third Street, Yakima, Yakima County, WA

VIEW LOOKING NORTHWEST TOWARD SOUTHEAST CORNER OF SETTLING RESERVOIR NO. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW LOOKING NORTHWEST TOWARD SOUTHEAST CORNER OF SETTLING RESERVOIR NO. 3. THE SOUTHWEST CORNER OF SETTLING RESERVOIR NO. 1 IS AT THE FAR LEFT. THE BLAISDELL SLOW SAND FILTER WASHING MACHINE IS SEEN AT THE RIGHT. THE SOUTHERN PACIFIC RAILROAD RESERVOIR IS SEEN ON THE HORIZON AT LEFT. JONES STREET IS IN THE FOREGROUND. - Yuma Main Street Water Treatment Plant, Jones Street at foot of Main Street, Yuma, Yuma County, AZ

Next-Generation MDAC Discrimination Procedure Using Multi-Dimensional Spectral Analyses

DTIC Science & Technology

2007-09-01

explosions near the Lop Nor, Novaya Zemlya, Semipalatinsk , Nevada, and Indian test sites . We have computed regional phase spectra and are correcting... test sites as mainly due to differences in explosion P and S corner frequencies. Fisk (2007) used source model fits to estimate Pn, Pg, and Lg corner...frequencies for Nevada Test Site (NTS) explosions and found that Lg corner frequencies exhibit similar scaling with source size as for Pn and Pg

Automatic streak endpoint localization from the cornerness metric

NASA Astrophysics Data System (ADS)

Sease, Brad; Flewelling, Brien; Black, Jonathan

2017-05-01

Streaked point sources are a common occurrence when imaging unresolved space objects from both ground- and space-based platforms. Effective localization of streak endpoints is a key component of traditional techniques in space situational awareness related to orbit estimation and attitude determination. To further that goal, this paper derives a general detection and localization method for streak endpoints based on the cornerness metric. Corners detection involves searching an image for strong bi-directional gradients. These locations typically correspond to robust structural features in an image. In the case of unresolved imagery, regions with a high cornerness score correspond directly to the endpoints of streaks. This paper explores three approaches for global extraction of streak endpoints and applies them to an attitude and rate estimation routine.

Development of Condensing Mesh Method for Corner Domain at Numerical Simulation Magnetic System

NASA Astrophysics Data System (ADS)

Perepelkin, E.; Tarelkin, A.; Polyakova, R.; Kovalenko, A.

2018-05-01

A magnetostatic problem arises in searching for the distribution of the magnetic field generated by magnet systems of many physics research facilities, e.g., accelerators. The domain in which the boundaryvalue problem is solved often has a piecewise smooth boundary. In this case, numerical calculations of the problem require the consideration of the solution behavior in the corner domain. In this work we obtained the upper estimation of the magnetic field growth and propose a method of condensing the differential grid near the corner domain of vacuum in case of 3-dimensional space based on this estimation. An example of calculating a real model problem for SDP NICA in the domain containing a corner point is given.

Assessment of Proper Bonding Methods and Mechanical Characterization FPGA CQFPs

NASA Technical Reports Server (NTRS)

Davis, Milton C.

2008-01-01

This presentation discusses fractured leads on field-programmable gate array (FPGA) during flight vibration. Actions taken to determine root cause and resolution of the failure include finite element analysis (FEA) and vibration testing and scanning electron microscopy (with X-ray microanalysis) and energy dispersive spectrometry (SEM/EDS) failure assessment. Bonding methods for surface mount parts is assessed, including critical analysis and assessment of random fatigue damage. Regarding ceramic quad flat pack (CQFP) lead fracture, after disassembling the attitude control electronics (ACE) configuration, photographs showed six leads cracked on FPGA RTSX72SU-1 CQ208B package located on the RWIC card. An identical package (FPGA RTSX32SU-1 CQ208B) mounted on the RWIC did not results in cracked pins due to vibration. FPGA lead failure theories include workmanship issues in the lead-forming, material defect in the leads of the FPGA packages, and the insecure mounting of the board in the card guides, among other theories. Studies were conducted using simple calculations to determine the response and fatigue life of the package. Shorter packages exhibited more response when loaded by out-of-plane displacement of PCB while taller packages exhibit more response when loaded by in-plane acceleration of PCB. Additionally, under-fill did not contribute to reducing stress in leads due to out-of-plane PCB loading or from component twisting, as much as corner bonding. The combination of corner bond and under-fill is best to address mechanical and thermal S/C environment. Test results of bonded parts showed reduced (dampened) amplitude and slightly shifted peaks at the un-bonded natural frequency and an additional response at the bonded frequency. Stress due to PCBB out-of-plane loading was decreased on in the corners when only a corner bond was used. Future work may address CQFP fatigue assessment, including the investigation of discrepancy in predicted fatigue damage, as well as comparing fatigue life and fatigue damage cycle ration computed using FEA and Miner's rule to results from a fatigue assessment software program.

Corrosion and hydrogen pick-up behaviors of cladding and structural components in BWR high burnup 9x9 lead use assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyashita, Toshiyasu; Nakae, Nobuo; Ogata, Keizo

The high burnup BWR 9x9 lead use fuel assemblies, which have been designed for maximum assembly burnup of 55 GWd/t in Japan, have been examined after irradiations to confirm the reliability of the current safety evaluation methodology, and to accumulate data to judge the adequacy to apply it to the future higher burnup fuel. After 3 and 5 cycle irradiations, post irradiation examinations were performed for both 9x9 Type-A and Type-B fuel assemblies. Both Type LUAs utilize Zry-2 claddings, while there are deviation in the contents of impurity and alloying elements between Type-A and Type-B, especially in Fe and Simore » concentration. Measured oxide thicknesses of fuel rods showed no significant difference between after 3 and 5 cycle irradiation except for some rods at corner position in Type B LUA. The axial profile of hydrogen concentration and oxide thickness for the corner rods in Type B LUA after 5 cycle irradiation had peaks at the second lowest span from the bottom. The maximum oxide thickness is about 50 {mu}m on the surface facing the bundle outside at the second lowest span and dense hydrides layer (Hydride rim) is observed in peripheral region of cladding showing unexpected high hydrogen concentration. The results of calculated thermal-hydraulic conditions show that the thermal neutron flux at the corner position was higher than the other position. On the other hand, the void fraction and the mass flux were relatively lower at the corner position. The oxide thickness on spacer band and spacer cell of Zry-2 increases from 3 to 5 cycle irradiations. Spacer band of Zry-4 showed significantly thick oxide after 5 cycle irradiations but Hydrogen concentration was relatively small in contrast its obviously thick oxide in comparison with Zry-2 spacer bands. The large increase in hydrogen concentration was measured in Zry-2 spacers after 5 cycle irradiations and the evaluated hydrogen pick-up rate also increased remarkably. (authors)« less

The distribution, structure, and composition of freshwater ice deposits in Bolivian salt lakes

USGS Publications Warehouse

Hurlbert, S.H.; Chang, Cecily C.Y.

1988-01-01

Freshwater ice deposits are described from seven, high elevation (4117-4730 m), shallow (mean depth <30 cm), saline (10-103 g l-1) lakes in the southwestern corner of Bolivia. The ice deposits range to several hundred meters in length and to 7 m in height above the lake or playa surface. They are located near the lake or salar margins; some are completely surrounded by water, others by playa deposits or salt crusts. Upper surfaces and sides of the ice deposits usually are covered by 20-40 cm of white to light brown, dry sedimentary materials. Calcite is the dominant crystalline mineral in these, and amorphous materials such as diatom frustules and volcanic glass are also often abundant. Beneath the dry overburden the ice occurs primarily as horizontal lenses 1-1000 mm thick, irregularly alternating with strata of frozen sedimentary materials. Ice represents from 10 to 87% of the volume of the deposits and yields freshwater (TFR <3 g l-1) when melted. Oxygen isotope ratios for ice are similar to those for regional precipitation and shoreline seeps but much lower than those for the lakewaters. Geothermal flux is high in the region as evidenced by numerous hot springs and deep (3.0-3.5 m) sediment temperatures of 5-10??C. This flux is one cause of the present gradual wasting away of these deposits. Mean annual air temperatures for the different lakes probably are all in the range of -2 to 4??C, and mean midwinter temperatures about 5??C lower. These deposits apparently formed during colder climatic conditions by the freezing of low salinity porewaters and the building up of segregation ice lenses. ?? 1988 Dr W. Junk Publishers.

Estimating global and North American methane emissions with high spatial resolution using GOSAT satellite data

NASA Astrophysics Data System (ADS)

Turner, A. J.; Jacob, D. J.; Wecht, K. J.; Maasakkers, J. D.; Biraud, S. C.; Boesch, H.; Bowman, K. W.; Deutscher, N. M.; Dubey, M. K.; Griffith, D. W. T.; Hase, F.; Kuze, A.; Notholt, J.; Ohyama, H.; Parker, R.; Payne, V. H.; Sussmann, R.; Velazco, V. A.; Warneke, T.; Wennberg, P. O.; Wunch, D.

2015-02-01

We use 2009-2011 space-borne methane observations from the Greenhouse Gases Observing SATellite (GOSAT) to constrain global and North American inversions of methane emissions with 4° × 5° and up to 50 km × 50 km spatial resolution, respectively. The GOSAT data are first evaluated with atmospheric methane observations from surface networks (NOAA, TCCON) and aircraft (NOAA/DOE, HIPPO), using the GEOS-Chem chemical transport model as a platform to facilitate comparison of GOSAT with in situ data. This identifies a high-latitude bias between the GOSAT data and GEOS-Chem that we correct via quadratic regression. The surface and aircraft data are subsequently used for independent evaluation of the methane source inversions. Our global adjoint-based inversion yields a total methane source of 539 Tg a-1 and points to a large East Asian overestimate in the EDGARv4.2 inventory used as a prior. Results serve as dynamic boundary conditions for an analytical inversion of North American methane emissions using radial basis functions to achieve high resolution of large sources and provide full error characterization. We infer a US anthropogenic methane source of 40.2-42.7 Tg a-1, as compared to 24.9-27.0 Tg a-1 in the EDGAR and EPA bottom-up inventories, and 30.0-44.5 Tg a-1 in recent inverse studies. Our estimate is supported by independent surface and aircraft data and by previous inverse studies for California. We find that the emissions are highest in the South-Central US, the Central Valley of California, and Florida wetlands, large isolated point sources such as the US Four Corners also contribute. We attribute 29-44% of US anthropogenic methane emissions to livestock, 22-31% to oil/gas, 20% to landfills/waste water, and 11-15% to coal with an additional 9.0-10.1 Tg a-1 source from wetlands.

Ground-water resources and geology of Waukesha County, Wisconsin

USGS Publications Warehouse

Gonthier, Joseph B.

1975-01-01

Good-quality water is available from the sand-and-gravel, Niagara, and sandstone aquifers in Waukesha County, Wis. As much as 15 gallons per minute (0.95 litres per second) can be obtained from wells almost everywhere in the county. Several hundred gallons per minute are available from aquifers in the glacial drift that fill bedrock valleys to thicknesses of 300 feet (91 metres) or more. Estimated well yields from much of the surficial outwash in western Waukesha County exceed 500 gallons per minute (31 litres per second). Estimated well yields from most of the Niagara aquifer, a dolomite as much as 325 feet (99 metres) thick in the eastern two-thirds of the county, exceed 50 gallons per minute (3.2 litres per second). The sandstone aquifer underlies the entire county and ranges in thickness from about 400 feet (120 metres) in the northwest corner to about 2,400 feet (730 metres) in the southeast corner. This aquifer yields more than 1,000 gallons per minute (63 litres per second) to wells over most of the county and is the principal source for municipal and subdivision water. Ground water in Waukesha County is of good quality and is suitable for most uses. Most of the water is a calcium magnesium bicarbonate type, is very hard [more than 180 mg/l (milligrams per litre) hardness], and requires softening for some uses. The ground water locally contains iron and manganese concentrations that exceed the limits (0.3 and 0.05 mg/l, respectively) recommended by the U.S. Public Health Service (1962, p. 7). Water high in sulfate and dissolved solids (saline water) is present locally in the Niagara and sandstone aquifers. Water from one well contained excessive nitrate (more than 45 mg/l). With one exception, wells sampled at irregular intervals indicated no significant changes in their chemical characteristics with time. About 24.3 million gallons per day (1.06 cubic metres per second) of ground water was pumped in the county in 1970. Sixty-two percent was withdrawn from the sandstone aquifer. More than one-half of the latter amount was for domestic use, and more than one-third was for industrial and commercial uses. 

Diffusion of small Cu islands on the Ni(111) surface: A self-learning kinetic Monte Carlo study

NASA Astrophysics Data System (ADS)

Acharya, Shree Ram; Shah, Syed Islamuddin; Rahman, Talat S.

2017-08-01

We elucidate the diffusion kinetics of a heteroepitaxial system consisting of two-dimensional small (1-8 atoms) Cu islands on the Ni(111) surface at (100-600) K using the Self-Learning Kinetic Monte Carlo (SLKMC-II) method. Study of the statics of the system shows that compact CuN (3≤N≤8) clusters made up of triangular units on fcc occupancy sites are the energetically most stable structures of those clusters. Interestingly, we find a correlation between the height of the activation energy barrier (Ea) and the location of the transition state (TS). The Ea of processes for Cu islands on the Ni(111) surface are in general smaller than those of their counterpart Ni islands on the same surface. We find this difference to correlate with the relative strength of the lateral interaction of the island atoms in the two systems. While our database consists of hundreds of possible processes, we identify and discuss the energetics of those that are the most dominant, or are rate-limiting, or most contributory to the diffusion of the islands. Since the Ea of single- and multi-atom processes that convert compact island shapes into non-compact ones are larger (with a significantly smaller Ea for their reverse processes) than that for the collective (concerted) motion of the island, the later dominate in the system kinetics - except for the cases of the dimer, pentamer and octamer. Short-jump involving one atom, long jump dimer-shearing, and long-jump corner shearing (via a single-atom) are, respectively, the dominating processes in the diffusion of the dimer, pentamer and octamer. Furthermore single-atom corner-rounding are the rate-limiting processes for the pentamer and octamer islands. Comparison of the energetics of selected processes and lateral interactions obtained from semi-empirical interatomic potentials with those from density functional theory show minor quantitative differences and overall qualitative agreement.

Evaluation of finite-element models and stress-intensity factors for surface cracks emanating from stress concentrations

NASA Technical Reports Server (NTRS)

Tan, P. W.; Raju, I. S.; Shivakumar, K. N.; Newman, J. C., Jr.

1990-01-01

A re-evaluation of the 3-D finite-element models and methods used to analyze surface crack at stress concentrations is presented. Previous finite-element models used by Raju and Newman for surface and corner cracks at holes were shown to have ill-shaped elements at the intersection of the hole and crack boundaries. Improved models, without these ill-shaped elements, were developed for a surface crack at a circular hole and at a semi-circular edge notch. Stress-intensity factors were calculated by both the nodal-force and virtual-crack-closure methods. Comparisons made between the previously developed stress-intensity factor equations and the results from the improved models agreed well except for configurations with large notch-radii-to-plate-thickness ratios. Stress-intensity factors for a semi-elliptical surface crack located at the center of a semi-circular edge notch in a plate subjected to remote tensile loadings were calculated using the improved models.

Streamer propagation in air near and on curved dielectrics

NASA Astrophysics Data System (ADS)

Dubinova, Anna; Ebert, Ute

2016-09-01

We simulate propagation of a positive streamer in air around a curved dielectric with a pronounced shading effect. In our setup a positive streamer is launched at the tip of a pin anode and propagates towards a grounded plate cathode. On the way of the streamer propagation path we place a curved dielectric body (e.g., a dielectric ball) of a diameter larger than the streamer diameter. This obstacle makes a streamer move around it. At the corner of the dielectric a surface streamer has a choice of moving along the surface or moving away from it. We explore physical mechanisms that can force a surface streamer to move all the way around a curved dielectric in air and nitrogen-oxygen mixtures. The potential candidates are secondary electron emission such as photoemission or field emission, higher dielectric permittivity, surface charge, lack of photoionization (in pure nitrogen). The problem is relevant for high-voltage technology, where surface streamers are often to be avoided. This research is supported by ABB Corporate Research.

Kinematic hardening of a porous limestone

NASA Astrophysics Data System (ADS)

Cheatham, J. B.; Allen, M. B.; Celle, C. C.

1984-10-01

A concept for a kinematic hardening yield surface in stress space for Cordova Cream limestone (Austin Chalk) developed by Celle and Cheatham (1981) has been improved using Ziegler's modification of Prager's hardening rule (Ziegler, 1959). Data to date agree with the formulated concepts. It is shown how kinematic hardening can be used to approximate the yield surface for a wide range of stress states past the initial yield surface. The particular difficulty of identifying the yield surface under conditions of unloading or extension is noted. A yield condition and hardening rule which account for the strain induced anisotropy in Cordova Cream Limestone were developed. Although the actual yield surface appears to involve some change of size and shape, it is concluded that true kinematic hardening provides a basis for engineering calculations.

Robust feature detection and local classification for surfaces based on moment analysis.

PubMed

Clarenz, Ulrich; Rumpf, Martin; Telea, Alexandru

2004-01-01

The stable local classification of discrete surfaces with respect to features such as edges and corners or concave and convex regions, respectively, is as quite difficult as well as indispensable for many surface processing applications. Usually, the feature detection is done via a local curvature analysis. If concerned with large triangular and irregular grids, e.g., generated via a marching cube algorithm, the detectors are tedious to treat and a robust classification is hard to achieve. Here, a local classification method on surfaces is presented which avoids the evaluation of discretized curvature quantities. Moreover, it provides an indicator for smoothness of a given discrete surface and comes together with a built-in multiscale. The proposed classification tool is based on local zero and first moments on the discrete surface. The corresponding integral quantities are stable to compute and they give less noisy results compared to discrete curvature quantities. The stencil width for the integration of the moments turns out to be the scale parameter. Prospective surface processing applications are the segmentation on surfaces, surface comparison, and matching and surface modeling. Here, a method for feature preserving fairing of surfaces is discussed to underline the applicability of the presented approach.

Small-crack effects in high-strength aluminum alloys

NASA Technical Reports Server (NTRS)

Newman, J. C., Jr.; Wu, X. R.; Venneri, S. L.; Li, C. G.

1994-01-01

The National Aeronautics and Space Administration and the Chinese Aeronautical Establishment participated in a Fatigue and Fracture Mechanics Cooperative Program. The program objectives were to identify and characterize crack initiation and growth of small cracks (10 microns to 2 mm long) in commonly used US and PRC aluminum alloys, to improve fracture mechanics analyses of surface- and corner-crack configurations, and to develop improved life-prediction methods. Fatigue and small-crack tests were performed on single-edgenotch tension (SENT) specimens and large-crack tests were conducted on center-crack tension specimens for constant-amplitude (stress ratios of -1, 0, and 0.5) and Mini-TWIST spectrum loading. The plastic replica method was used to monitor the initiation and growth of small fatigue cracks at the semicircular notch. Crack growth results from each laboratory on 7075-T6 bare and LC9cs clad aluminum alloys agreed well and showed that fatigue life was mostly crack propagation from a material defect (inclusion particles or void) or from the cladding layer. Finite-element and weight-function methods were used to determine stress intensity factors for surface and corner cracks in the SENT specimens. Equations were then developed and used in a crack growth and crack-closure model to correlate small- and large-crack data and to make life predictions for various load histories. The cooperative program produced useful experimental data and efficient analysis methods for improving life predictions. The results should ultimately improve aircraft structural reliability and safety.

Subsidence detection by TerraSAR-X interferometry on a network of natural persistent scatterers and artificial corner reflectors

NASA Astrophysics Data System (ADS)

Yu, Bing; Liu, Guoxiang; Li, Zhilin; Zhang, Rui; Jia, Hongguo; Wang, Xiaowen; Cai, Guolin

2013-08-01

The German satellite TerraSAR-X (TSX) is able to provide high-resolution synthetic aperture radar (SAR) images for mapping surface deformation by the persistent scatterer interferometry (PSI) technique. To extend the application of PSI in detecting subsidence in areas with frequent surface changes, this paper presents a method of TSX PSI on a network of natural persistent scatterers (NPSs) and artificial corner reflectors (CRs) deployed on site. We select a suburban area of southwest Tianjin (China) as the testing site where 16 CRs and 10 leveling points (LPs) are deployed, and utilize 13 TSX images collected over this area between 2009 and 2010 to extract subsidence by the method proposed. Two types of CRs are set around the fishponds and crop parcels. 6 CRs are the conventional ones, i.e., fixed CRs (FCRs), while 10 CRs are the newly-designed ones, i.e., so-called portable CRs (PCRs) with capability of repeatable installation. The numerical analysis shows that the PCRs have the higher temporal stability of radar backscattering than the FCRs, and both of them are better than the NPSs in performance of radar reflectivity. The comparison with the leveling data at the CRs and LPs indicates that the subsidence measurements derived by the TSX PSI method can reach up to a millimeter level accuracy. This demonstrates that the TSX PSI method based on a network of NPSs and CRs is useful for detecting land subsidence in cultivated lands.

Comments on numerical solution of boundary value problems of the Laplace equation and calculation of eigenvalues by the grid method

NASA Technical Reports Server (NTRS)

Lyusternik, L. A.

1980-01-01

The mathematics involved in numerically solving for the plane boundary value of the Laplace equation by the grid method is developed. The approximate solution of a boundary value problem for the domain of the Laplace equation by the grid method consists of finding u at the grid corner which satisfies the equation at the internal corners (u=Du) and certain boundary value conditions at the boundary corners.

Clinical outcomes of proximal row carpectomy versus four-corner arthrodesis for post-traumatic wrist arthropathy: a systematic review.

PubMed

Saltzman, B M; Frank, J M; Slikker, W; Fernandez, J J; Cohen, M S; Wysocki, R W

2015-06-01

We conducted a systematic review of studies reporting clinical outcomes after proximal row carpectomy or to four-corner arthrodesis for scaphoid non-union advanced collapse or scapholunate advanced collapse arthritis. Seven studies (Levels I-III; 240 patients, 242 wrists) were evaluated. Significantly different post-operative values were as follows for four-corner arthrodesis versus proximal row carpectomy groups: wrist extension, 39 (SD 11º) versus 43 (SD 11º); wrist flexion, 32 (SD 10º) versus 36 (SD 11º); flexion-extension arc, 62 (SD 14º) versus 75 (SD 10º); radial deviation, 14 (SD 5º) versus 10 (SD 5º); hand grip strength as a percentage of contralateral side, 74% (SD 13) versus 67% (SD 16); overall complication rate, 29% versus 14%. The most common post-operative complications were non-union (grouped incidence, 7%) after four-corner arthrodesis and synovitis and clinically significant oedema (3.1%) after proximal row carpectomy. Radial deviation and post-operative hand grip strength (as a percentage of the contralateral side) were significantly better after four-corner arthrodesis. Four-corner arthrodesis gave significantly greater post-operative radial deviation and grip strength as a percentage of the opposite side. Wrist flexion, extension, and the flexion-extension arc were better after proximal row carpectomy, which also had a lower overall complication rate. © The Author(s) 2014.

Experimental evaluation of two turning vane designs for fan drive corner of 0.1-scale model of NASA Lewis Research Center's proposed altitude wind tunnel

NASA Technical Reports Server (NTRS)

Boldman, Donald R.; Moore, Royce D.; Shyne, Rickey J.

1987-01-01

Two turning vane designs were experimentally evaluated for corner 2 of a 0.1 scale model of the NASA Lewis Research Center's proposed Altitude Wind Tunnel (AWT). Corner 2 contained a simulated shaft fairing for a fan drive system to be located downstream of the corner. The corner was tested with a bellmouth inlet followed by a 0.1 scale model of the crossleg diffuser designed to connect corners 1 and 2 of the AWT. Vane A was a controlled-diffusion airfoil shape; vane B was a circular-arc airfoil shape. The A vanes were tested in several arrangements which included the resetting of the vane angle by -5 degrees or the removal of the outer vane. The lowest total pressure loss for vane A configuration was obtained at the negative reset angle. The loss coefficient increased slightly with the Mach number, ranging from 0.165 to 0.175 with a loss coefficient of 0.170 at the inlet design Mach number of 0.24. Removal of the outer vane did not alter the loss. Vane B loss coefficients were essentially the same as those for the reset vane A configurations. The crossleg diffuser loss coefficient was 0.018 at the inlet design Mach number of 0.33.

Formative Evaluation for a Healthy Corner Store Initiative in Pitt County, North Carolina: Assessing the Rural Food Environment, Part 1

PubMed Central

Bringolf, Karamie R.; Lawton, Katherine K.; McGuirt, Jared T.; Wall-Bassett, Elizabeth; Morgan, Jo; Laska, Melissa Nelson; Sharkey, Joseph R.

2013-01-01

Introduction Obesity prevalence in the rural United States is higher than in urban or suburban areas, perhaps as a result of the food environment. Because rural residents live farther from supermarkets than their urban- and suburban-dwelling counterparts, they may be more reliant on smaller corner stores that offer fewer healthful food items. Methods As part of a Communities Putting Prevention to Work (CPPW) healthy corner store initiative, we reviewed audit tools in the fall of 2010 to measure the consumer food environment in eastern North Carolina and chose the NEMS-S-Rev (Nutrition Environment Measures Survey-Stores-Revised) to assess 42 food stores. During the spring and summer of 2011, 2 trained graduate assistants audited stores, achieving interrater reliability of at least 80%. NEMS-S-Rev scores of stores in rural versus urban areas were compared. Results Overall, healthful foods were less available and of lower quality in rural areas than in urban areas. NEMS-S-Rev scores indicated that healthful foods were more likely to be available and had similar pricing and quality in rural corner stores than in urban corner stores. Conclusion Food store audit data provided a baseline to implement and evaluate a CPPW healthy corner store initiative in Pitt County. This work serves as a case study, providing lessons learned for engaging community partners when conducting rural food store audits. PMID:23866165

The cross-cut statistic and its sensitivity to bias in observational studies with ordered doses of treatment.

PubMed

Rosenbaum, Paul R

2016-03-01

A common practice with ordered doses of treatment and ordered responses, perhaps recorded in a contingency table with ordered rows and columns, is to cut or remove a cross from the table, leaving the outer corners--that is, the high-versus-low dose, high-versus-low response corners--and from these corners to compute a risk or odds ratio. This little remarked but common practice seems to be motivated by the oldest and most familiar method of sensitivity analysis in observational studies, proposed by Cornfield et al. (1959), which says that to explain a population risk ratio purely as bias from an unobserved binary covariate, the prevalence ratio of the covariate must exceed the risk ratio. Quite often, the largest risk ratio, hence the one least sensitive to bias by this standard, is derived from the corners of the ordered table with the central cross removed. Obviously, the corners use only a portion of the data, so a focus on the corners has consequences for the standard error as well as for bias, but sampling variability was not a consideration in this early and familiar form of sensitivity analysis, where point estimates replaced population parameters. Here, this cross-cut analysis is examined with the aid of design sensitivity and the power of a sensitivity analysis. © 2015, The International Biometric Society.

Investigation of the layout and optical proximity correction effects to control the trench etching process on 4H-SiC

NASA Astrophysics Data System (ADS)

Kyoung, Sinsu; Jung, Eun-Sik; Sung, Man Young

2017-07-01

Although trench gate and super-junction technology have micro-trench problems when applied to the SiC process due to the material characteristics. In this paper, area effects are analyzed from the test element group with various patterns and optical proximity correction (OPC) methods are proposed and analyzed to reduce micro-trenches in the SiC trench etching process. First, the loading effects were analyzed from pattern samples with various trench widths (Wt). From experiments, the area must limited under a proper size for a uniform etching profile and reduced micro-trenches because a wider area accelerates the etch rate. Second, the area effects were more severely unbalanced at corner patterns because the corner pattern necessarily has an in-corner and out-corner that have different etching areas to each other. We can balance areas using OPC patterns to overcome this. Experiments with OPC represented improved micro-trench profile from when comparing differences of trench depth (Δdt) at out corner and in corner. As a result, the area effects can be used to improve the trench profile with optimized etching process conditions. Therefore, the trench gate and super-junction pillar of the SiC power MOSFET can have an improved uniform profile without micro-trenches using proper design and OPC.[Figure not available: see fulltext.

More vertical etch profile using a Faraday cage in plasma etching

NASA Astrophysics Data System (ADS)

Cho, Byeong-Ok; Hwang, Sung-Wook; Ryu, Jung-Hyun; Moon, Sang Heup

1999-05-01

Scanning electron microscope images of sidewalls obtained by plasma etching of an SiO2 film with and without a Faraday cage have been compared. When the substrate film is etched in the Faraday cage, faceting is effectively suppressed and the etch profile becomes more vertical regardless of the process conditions. This is because the electric potential in the cage is nearly uniform and therefore distortion of the electric field at the convex corner of a microfeature is prevented. The most vertical etch profile is obtained when the cage is used in fluorocarbon plasmas, where faceting is further suppressed due to the decrease in the chemical sputtering yield and the increase in the radical/ion flux on the substrate.

Impact of a pilot walking school bus intervention on children's pedestrian safety behaviors: a pilot study.

PubMed

Mendoza, Jason A; Watson, Kathy; Chen, Tzu-An; Baranowski, Tom; Nicklas, Theresa A; Uscanga, Doris K; Hanfling, Marcus J

2012-01-01

Walking school buses (WSB) increased children's physical activity, but impact on pedestrian safety behaviors (PSB) is unknown. We tested the feasibility of a protocol evaluating changes to PSB during a WSB program. Outcomes were school-level street crossing PSB prior to (Time 1) and during weeks 4-5 (Time 2) of the WSB. The protocol collected 1252 observations at Time 1 and 2548 at Time 2. Mixed model analyses yielded: intervention schoolchildren had 5-fold higher odds (p<0.01) of crossing at the corner/crosswalk but 5-fold lower odds (p<0.01) of stopping at the curb. The protocol appears feasible for documenting changes to school-level PSB. Copyright © 2011 Elsevier Ltd. All rights reserved.

Experimental Investigations on Subsequent Yield Surface of Pure Copper by Single-Sample and Multi-Sample Methods under Various Pre-Deformation.

PubMed

Liu, Gui-Long; Huang, Shi-Hong; Shi, Che-Si; Zeng, Bin; Zhang, Ke-Shi; Zhong, Xian-Ci

2018-02-10

Using copper thin-walled tubular specimens, the subsequent yield surfaces under pre-tension, pre-torsion and pre-combined tension-torsion are measured, where the single-sample and multi-sample methods are applied respectively to determine the yield stresses at specified offset strain. The rule and characteristics of the evolution of the subsequent yield surface are investigated. Under the conditions of different pre-strains, the influence of test point number, test sequence and specified offset strain on the measurement of subsequent yield surface and the concave phenomenon for measured yield surface are studied. Moreover, the feasibility and validity of the two methods are compared. The main conclusions are drawn as follows: (1) For the single or multi-sample method, the measured subsequent yield surfaces are remarkably different from cylindrical yield surfaces proposed by the classical plasticity theory; (2) there are apparent differences between the test results from the two kinds of methods: the multi-sample method is not influenced by the number of test points, test order and the cumulative effect of residual plastic strain resulting from the other test point, while those are very influential in the single-sample method; and (3) the measured subsequent yield surface may appear concave, which can be transformed to convex for single-sample method by changing the test sequence. However, for the multiple-sample method, the concave phenomenon will disappear when a larger offset strain is specified.

Simulation research of the tire Basic Relaxation Model in conditions of the wheel cornering angle oscillations

NASA Astrophysics Data System (ADS)

Luty, W.

2016-09-01

- A description of the tire Basic Relaxation Model (BRM) is presented in this paper. Simulation research of the tire BRM model in conditions of oscillatory changes of the wheel cornering angle were performed. During the simulation tests the courses of changes in the value of lateral reaction force, transmitted by the wheel, as a response to the sinusoidal changes in the value of the wheel cornering angle have been presented. There have been compared the simulation results obtained for the model of tire-road interaction in two modes: including and not including the BRM. The simulation results allowed to verify prepared BRM and also to determine the influence of the tire relaxation process on the tire behavior in conditions of dynamic changes of the wheel cornering angle.

A method of camera calibration with adaptive thresholding

NASA Astrophysics Data System (ADS)

Gao, Lei; Yan, Shu-hua; Wang, Guo-chao; Zhou, Chun-lei

2009-07-01

In order to calculate the parameters of the camera correctly, we must figure out the accurate coordinates of the certain points in the image plane. Corners are the important features in the 2D images. Generally speaking, they are the points that have high curvature and lie in the junction of different brightness regions of images. So corners detection has already widely used in many fields. In this paper we use the pinhole camera model and SUSAN corner detection algorithm to calibrate the camera. When using the SUSAN corner detection algorithm, we propose an approach to retrieve the gray difference threshold, adaptively. That makes it possible to pick up the right chessboard inner comers in all kinds of gray contrast. The experiment result based on this method was proved to be feasible.

Multi-scale reflection modulator-based optical interconnects

NASA Astrophysics Data System (ADS)

Nair, Rohit

This dissertation describes the design, analysis, and experimental validation of micro- and macro-optical components for implementing optical interconnects at multiple scales for varied applications. Three distance scales are explored: millimeter, centimeter, and meter-scales. At the millimeter-scale, we propose the use of optical interconnects at the intra-chip level. With the rapid scaling down of CMOS critical dimensions in accordance to Moore's law, the bandwidth requirements of global interconnects in microprocessors has exceeded the capabilities of metal links. These are the wires that connect the most remote parts of the chip and are disproportionately problematic in terms of chip area and power consumption. Consequently, in the mid-2000s, we saw a shift in the chip architecture: a move towards multicore designs. However, this only delays the inevitable communication bottleneck between cores. To satisfy this bandwidth, we propose to replace the global metal interconnects with optical interconnects. We propose to use the hybrid integration of silicon with GaAs/AlAs-based multiple quantum well devices as optical modulators and photodetectors along with polymeric waveguides to transport the light. We use grayscale lithography to fabricate curved facets into the waveguides to couple light into the modulators and photodetectors. Next, at the chip-to-chip level in high-performance multiprocessor computing systems, communication distances vary from a few centimeters to tens of centimeters. An optical design for coupling light from off-chip lasers to on-chip surface-normal modulators is proposed in order to implement chip-to-chip free-space optical interconnects. The method uses a dual-prism module constructed from prisms made of two different glasses. The various alignment tolerances of the proposed system are investigated and found to be well within pick-and-place accuracies. For the off-chip lasers, vertical cavity surface emitting lasers (VCSELs) are proposed. The rationale behind using on-chip modulators rather than VCSELs is to avoid VCSEL thermal loads on chip, and because of higher reliability of modulators than VCSELs. Particularly above 10Gbps, an empirical model developed shows the rapid decrease of VCSEL median time to failure vs. data rate. Thus the proposed interconnect scheme which utilizes continuous wave VCSELs that are externally modulated by on-chip multiple quantum well modulators is applicable for chip-to-chip optical interconnects at 20Gbps and higher line data rates. Finally, for applications such as remote telemetry, where the interrogation distances can vary from a few meters to tens or even hundreds of meters we demonstrate a modulated retroreflector that utilizes InGaAs/InAlAs-based large-area multiple quantum well modulators on all three faces of a retroreflector. The large-area devices, fabricated by metalorganic chemical vapor deposition, are characterized in terms of the yield and leakage currents. A yield higher than that achieved previously using devices fabricated by molecular beam epitaxy is observed. The retroreflector module is constructed using standard FR4 printed circuit boards, thereby simplifying the wiring issue. A high optical contrast ratio of 8.23dB is observed for a drive of 20V. A free-standing PCB retroreflector is explored and found to have insufficient angular tolerances (+/-0.5 degrees). We show that the angular errors in the corner-cube construction can be corrected for using off-the-shelf optical components as opposed to mounting the PCBs on a precision corner cube, as has been done previously.

Detail view of upper southwest corner, showing representative view of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail view of upper southwest corner, showing representative view of cornice and window ornamentation - Hungarian Sick Benefit Societies Building, 1406-1418 State Street, Bridgeport, Fairfield County, CT

11. Exterior detail view of northeast corner, showing stucco finish ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Exterior detail view of northeast corner, showing stucco finish and woodwork details - American Railway Express Company Freight Building, 1060 Northeast Division Street, Bend, Deschutes County, OR

Oblique view of southeast corner; camera facing northwest. Mare ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Oblique view of southeast corner; camera facing northwest. - Mare Island Naval Shipyard, Defense Electronics Equipment Operating Center, I Street, terminus west of Cedar Avenue, Vallejo, Solano County, CA

Instructor Manual for Social Awareness and Influence Workshop

DTIC Science & Technology

2008-07-01

28 15 Module 2: Planning Phase Influence GoalI fl c l Evaluation of Situation v l ti f it ti Influence Strategy I fl c tr t y Phase 1...Inner corners of eyebrows raised, eyebrows drawn together Corner of lips pulled down Corner of lips tightened and pressed Eyebrows...being naïve, but I suppose I could pull a few strings and send in a requisition for more funding,” said James. “Can you guarantee me that I won’t be

Pavement Maintenance Management for Roads and Parking Lots.

DTIC Science & Technology

1981-10-01

PAVEMENT INSPECTION SHEET aRANCH SECT ION DA TE SAMPLE UNIT SURVEYED BY SLAB SIZE * 0 0 0 Distress Types !0 2f Blow- Up 3’ Polished Buckling/Shattering...10 21 Blow- up 31 Poisnec Buckling/Shatternrg Aggregate 0 1 22. Corner Break 32 Porouis 23. D’viOea SIcD 33 Ptmo,nq 9 24 Durability . " 34 Pancnout...Load Durability Drainage Other Factors Corner Break Blow- up Corner Break Faulting Divided Slab Ŕ" Cracking Divided Slab Lane/Shoulder Dropoff

Interpretive Overview of Cultural Resources in Saylorville Lake, Iowa. Volume 1,

DTIC Science & Technology

1985-09-01

Rice Corner Notched variety; CN9, Turin variety). Similar side notched points were found in horizons I and II at the Cherokee Sewer site (Anderson...1980) and in the Middle Archaic levels at Koster (Brown and Vierra 1983:182-4) and the Pigeon Roost Creek site (O’Brien and Warren 1983). The Rice ...triangular blades are like the Rice Corner Notched style of the Archaic periods. Slightly smaller Manker Corner Notched points (Figures A.6, A.13) are

Transition of Corner Cracks at Holes into Through-The-Thickness Cracks

DTIC Science & Technology

1983-12-01

upon an imaginary crack depth, which is arrived at by allowing the flaw to continually grow in the same elliptical shape it had when it penetrated the...approximately 0.75, and then they deteriorate rapidly . This value of 0.75 agrees with the value selected as the start of the transition region along the bore of...a corner crack emanating from a hole as it grows until it reaches final fracture. However, in a region near where the corner crack penetrates the back

Effects of Source RDP Models and Near-source Propagation: Implication for Seismic Yield Estimation

NASA Astrophysics Data System (ADS)

Saikia, C. K.; Helmberger, D. V.; Stead, R. J.; Woods, B. B.

- It has proven difficult to uniquely untangle the source and propagation effects on the observed seismic data from underground nuclear explosions, even when large quantities of near-source, broadband data are available for analysis. This leads to uncertainties in our ability to quantify the nuclear seismic source function and, consequently the accuracy of seismic yield estimates for underground explosions. Extensive deterministic modeling analyses of the seismic data recorded from underground explosions at a variety of test sites have been conducted over the years and the results of these studies suggest that variations in the seismic source characteristics between test sites may be contributing to the observed differences in the magnitude/yield relations applicable at those sites. This contributes to our uncertainty in the determination of seismic yield estimates for explosions at previously uncalibrated test sites. In this paper we review issues involving the relationship of Nevada Test Site (NTS) source scaling laws to those at other sites. The Joint Verification Experiment (JVE) indicates that a magnitude (mb) bias (δmb) exists between the Semipalatinsk test site (STS) in the former Soviet Union (FSU) and the Nevada test site (NTS) in the United States. Generally this δmb is attributed to differential attenuation in the upper-mantle beneath the two test sites. This assumption results in rather large estimates of yield for large mb tunnel shots at Novaya Zemlya. A re-examination of the US testing experiments suggests that this δmb bias can partly be explained by anomalous NTS (Pahute) source characteristics. This interpretation is based on the modeling of US events at a number of test sites. Using a modified Haskell source description, we investigated the influence of the source Reduced Displacement Potential (RDP) parameters ψ ∞ , K and B by fitting short- and long-period data simultaneously, including the near-field body and surface waves. In general, estimates of B and K are based on the initial P-wave pulse, which various numerical analyses show to be least affected by variations in near-source path effects. The corner-frequency parameter K is 20% lower at NTS (Pahute) than at other sites, implying larger effective source radii. The overshoot parameter B appears to be low at NTS (although variable) relative to other sites and is probably due to variations in source conditions. For a low B, the near-field data require a higher value of ψ ∞ to match the long-period MS and short-period mb observations. This flexibility in modeling proves useful in comparing released FSU yields against predictions based on mb and MS.

6. DETAIL OF FRONT ENTRANCE IN NORTHWEST CORNER. VIEW TO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. DETAIL OF FRONT ENTRANCE IN NORTHWEST CORNER. VIEW TO EAST. - Commercial & Industrial Buildings, International Harvester Company Showroom, Office & Warehouse, 10 South Main Street, Dubuque, Dubuque County, IA

16. Detail of southeast corner of Gwing, looking northwest ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. Detail of southeast corner of G-wing, looking northwest - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE

Magnetic second-order topological insulators and semimetals

NASA Astrophysics Data System (ADS)

Ezawa, Motohiko

2018-04-01

We propose magnetic second-order topological insulators (SOTIs). First, we study a three-dimensional model. It is pointed out that the previously proposed topological hinge insulator has actually surface states along the [001] direction in addition to hinge states. We gap out these surface states by introducing magnetization, obtaining a SOTI only with hinge states. The bulk topological number is the Z2 index protected by the combined symmetry of the fourfold rotation and the inversion symmetry. We next study two-dimensional magnetic SOTIs, where the corner states are robust also in the presence of the magnetization. Finally, we construct a magnetic second-order topological semimetal by layering the two-dimensional magnetic SOTIs, where hinge-arc states are robust also in the presence of the magnetization.

Nanostructured Metal Oxides for Stoichiometric Degradation of Chemical Warfare Agents.

PubMed

Štengl, Václav; Henych, Jiří; Janoš, Pavel; Skoumal, Miroslav

2016-01-01

Metal oxides have very important applications in many areas of chemistry, physics and materials science; their properties are dependent on the method of preparation, the morphology and texture. Nanostructured metal oxides can exhibit unique characteristics unlike those of the bulk form depending on their morphology, with a high density of edges, corners and defect surfaces. In recent years, methods have been developed for the preparation of metal oxide powders with tunable control of the primary particle size as well as of a secondary particle size: the size of agglomerates of crystallites. One of the many ways to take advantage of unique properties of nanostructured oxide materials is stoichiometric degradation of chemical warfare agents (CWAs) and volatile organic compounds (VOC) pollutants on their surfaces.

Bangor International/Dow AFB, Maine. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

DTIC Science & Technology

1981-11-06

UNCLASSIFIED 16 OISTRIBuJTION ST ATEMEN T I tin, Ro- Approved for public release; distribution unlimited. 𔄁 DISTRIBJTION ST ATEMEN’ oI rho *hottott *,I...temporary site at ground GM1-1l RO-2 Surfac level in ramp area. 6 Apr 60 Located approx 200 ft from corner Same RO-2A 13 ft of old rnwy 33 taxiway and...SAND TO VISION Os J ,’,~~~ 10aJ: o ~ i isII~ 13.*.6-. 2.2 1 v4,U " _.71 13.51 19 * 15. 1 o 3 1_7 _ 17_7_ 4; S ,I ’ 1 ’: SI .5 13.3’ .19.1 16 .t, 󈧰

The Design, Synthesis, and Characterization of Open Sites on Metal Clusters

NASA Astrophysics Data System (ADS)

Nigra, Michael Mark

Coordinatively unsaturated corner and edge atoms have been hypothesized to have the highest activity of sites responsible for many catalytic reactions on a metal surface. Recent studies have validated this hypothesis in varied reaction systems. However, quantification of different types of coordinatively unsaturated sites, and elucidation of their individual catalytic rates has remained a largely unresolved challenge when understanding catalysis on metal surfaces. Yet such structure-function knowledge would be invaluable to the design of more active and selective metal-surface catalysts in the future. I investigated the catalytic contributions of undercoordinated sites such as corner and edge atoms are investigated in a model reaction system using organic ligands bound to the gold nanoparticle surface. The catalyst consisted of 4 nm gold nanoparticles on a metal oxide support, using resazurin to resorufin as a model reaction system. My results demonstrate that in this system, corner atom sites are the most undercoordinated sites, and are over an order of magnitude more active when compared to undercoordinated edge atom sites, while terrace sites remain catalytically inactive for the reduction reaction of resazurin to resorufin. Catalytic activity has been also demonstrated for calixarene-bound gold nanoparticles using the reduction of 4-nitrophenol. With the 4-nitrophenol reduction reaction, a comparative study was undertaken to compare calixarene phosphine and calixarene thiol bound 4 nm gold particles. The results of the study suggested that a leached site was responsible for catalysis and not sites on the original gold nanoparticles. Future experiments with calixarene bound gold clusters could investigate ligand effects in reactions where the active site is not a leached or aggregated gold species, possibly in oxidation reactions, where electron-rich gold is hypothesized to be a good catalyst. The results that emphasize the enhanced catalytic activity of undercoordinated sites led me to synthesize small gold clusters consisting of a high fraction of coordinatively unsaturated open sites. This was enabled through an approach that utilized bulky calix[4]arene ligands that are bound to a gold core. Since the size of the calix[4]arene ligand is commensurate with the size of the gold cluster core, the calix[4]arene ligand does not pack closely together on the gold cluster surface. This in turn results in areas of accessible gold atom sites between ligands. Additionally, these calix[4]arene ligands prevent cluster aggregation and electronically tune the gold core in a manner conceptually similar to enzymes affecting reactivity through organic side-chains acting as ligands. I quantified the number of open sites that result from this packing problem on the gold cluster surface, using fluorescence probe chemisorption experiments. The results of these chemisorption measurements support the mechanical model of accessibility whereby accessibility is not dependent on the identity of the functional group, whether it be calixarene phosphines or N-heterocyclic carbenes, bound to the gold surface, but rather to the relative radii of curvature of bound ligands and the gold cluster core. Additional materials characterization was completed with transmission electron microscopy in both bright-field imaging of zeolites, in MCM-22 and delaminated ITQ-2 and UCB-1 materials, and in dark field imaging of glucan coatings on oxide particles. These materials could prove to be interesting materials as to use as supports for the calixarene-bound metal clusters described above or for other metal clusters.

Spectral dependence of backscattering coefficient of mixed phase clouds over West Africa measured with two-wavelength Raman polarization lidar: Features attributed to ice-crystals corner reflection

NASA Astrophysics Data System (ADS)

Veselovskii, I.; Goloub, P.; Podvin, T.; Tanre, D.; Ansmann, A.; Korenskiy, M.; Borovoi, A.; Hu, Q.; Whiteman, D. N.

2017-11-01

The existing models predict that corner reflection (CR) of laser radiation by simple ice crystals of perfect shape, such as hexagonal columns or plates, can provide a significant contribution to the ice cloud backscattering. However in real clouds the CR effect may be suppressed due to crystal deformation and surface roughness. In contrast to the extinction coefficient, which is spectrally independent, consideration of diffraction associated with CR results in a spectral dependence of the backscattering coefficient. Thus measuring the spectral dependence of the cloud backscattering coefficient, the contribution of CR can be identified. The paper presents the results of profiling of backscattering coefficient (β) and particle depolarization ratio (δ) of ice and mixed-phase clouds over West Africa by means of a two-wavelength polarization Mie-Raman lidar operated at 355 nm and 532 nm during the SHADOW field campaign. The lidar observations were performed at a slant angle of 43 degree off zenith, thus CR from both randomly oriented crystals and oriented plates could be analyzed. For the most of the observations the cloud backscatter color ratio β355/β532 was close to 1.0, and no spectral features that might indicate the presence of CR of randomly oriented crystals were revealed. Still, in two measurement sessions we observed an increase of backscatter color ratio to a value of nearly 1.3 simultaneously with a decrease of the spectral depolarization ratio δ355/δ532 ratio from 1.0 to 0.8 inside the layers containing precipitating ice crystals. We attribute these changes in optical properties to corner reflections by horizontally oriented ice plates.

De-icing of the altitude wind tunnel turning vanes by electro-magnetic impulse

NASA Technical Reports Server (NTRS)

Zumwalt, G. W.; Ross, R.

1986-01-01

The Altitude Wind Tunnel at the NASA-Lewis facility is being proposed for a refurbishment and moderization. Two major changes are: (1) the increasing of the test section Mach number to 0.90, and (2) the addition of spray nozzles to provide simulation of flight in icing clouds. Features to be retained are the simulation of atmospheric temperature and pressure to 50,000 foot altitude and provision for full-scale aircraft engine operation by the exhausting of the aircraft combustion gases and ingestion of air to replace that used in combustion. The first change required a re-design of the turning vanes in the two corners downstream of the test section due to the higher Mach number at the corners. The second change threatens the operation of the turning vanes by the expected ice build-up, particulary on the first-corner vanes. De-icing by heat has two drawbacks: (1) an extremely large amount of heat is required, and (2) the melted ice would tend to collect as ice on some other surfaces in the tunnel, namely, the tunnel propellers and the cooling coils. An alternate de-icing method had been under development for three years under NASA-Lewis grants to the Wichita State University. This report describes the electro-impulse de-icing (EIDI) method and the testing work done to assess its applicability to wind tunnel turning vane de-icing. Tests were conducted in the structural dynamics laboratory and in the NASA Icing Research Tunnel. Good ice protection was achieved at lower power consumption and at a wide range of tunnel operations conditions. Recommendations for design and construction of the system for this application of the EIDI method are given.

A proposed method for wind velocity measurement from space

NASA Technical Reports Server (NTRS)

Censor, D.; Levine, D. M.

1980-01-01

An investigation was made of the feasibility of making wind velocity measurements from space by monitoring the apparent change in the refractive index of the atmosphere induced by motion of the air. The physical principle is the same as that resulting in the phase changes measured in the Fizeau experiment. It is proposed that this phase change could be measured using a three cornered arrangement of satellite borne source and reflectors, around which two laser beams propagate in opposite directions. It is shown that even though the velocity of the satellites is much larger than the wind velocity, factors such as change in satellite position and Doppler shifts can be taken into account in a reasonable manner and the Fizeau phase measured. This phase measurement yields an average wind velocity along the ray path through the atmosphere. The method requires neither high accuracy for satellite position or velocity, nor precise knowledge of the refractive index or its gradient in the atmosphere. However, the method intrinsically yields wind velocity integrated along the ray path; hence to obtain higher spatial resolution, inversion techniques are required.

Southeast corner with overhead crane in foreground Bureau of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Southeast corner with overhead crane in foreground - Bureau of Mines Boulder City Experimental Station, Titanium Development Plant, Date Street north of U.S. Highway 93, Boulder City, Clark County, NV

1. EXTERIOR SOUTHWEST CORNER VIEW, FACING NORTHEAST. BUILDING NO. 42 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. EXTERIOR SOUTHWEST CORNER VIEW, FACING NORTHEAST. BUILDING NO. 42 GARAGE & TRANSPORTATION MAINTENANCE FACILITY - NASA Industrial Plant, Garage & Transportation Maintenance Facility, 12214 Lakewood Boulevard, Downey, Los Angeles County, CA

2. EXTERIOR SOUTHEAST CORNER VIEW, FACING NORTHWEST. BUILDING NO 42 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. EXTERIOR SOUTHEAST CORNER VIEW, FACING NORTHWEST. BUILDING NO 42 GARAGE & TRANSPORTATION MAINTENANCE FACILITY - NASA Industrial Plant, Garage & Transportation Maintenance Facility, 12214 Lakewood Boulevard, Downey, Los Angeles County, CA

4. EXTERIOR NORTHWEST CORNER VIEW, FACING SOUTHEAST. BUILDING NO 42 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. EXTERIOR NORTHWEST CORNER VIEW, FACING SOUTHEAST. BUILDING NO 42 GARAGE & TRANSPORTATION MAINTENANCE FACILITY - NASA Industrial Plant, Garage & Transportation Maintenance Facility, 12214 Lakewood Boulevard, Downey, Los Angeles County, CA

3. EXTERIOR NORTHEAST CORNER VIEW, FACING SOUTHWEST. BUILDING NO 42 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. EXTERIOR NORTHEAST CORNER VIEW, FACING SOUTHWEST. BUILDING NO 42 GARAGE & TRANSPORTATION MAINTENANCE FACILITY - NASA Industrial Plant, Garage & Transportation Maintenance Facility, 12214 Lakewood Boulevard, Downey, Los Angeles County, CA

22. INTERIOR, FIRST FLOOR, EAST SECTION, NORTHEAST ROOM, NORTHWEST CORNER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. INTERIOR, FIRST FLOOR, EAST SECTION, NORTHEAST ROOM, NORTHWEST CORNER (NOTE EXPOSED BRICK NOGGING) - Peter Burr House, Vicinity of State Route 9 & Ridge Road, Shenandoah Junction, Jefferson County, WV

22. SOUTHWEST CORNER OF BANKING ROOM, FROM EAST, SHOWING CLOCK ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. SOUTHWEST CORNER OF BANKING ROOM, FROM EAST, SHOWING CLOCK ON SOUTH WALL AND TWO MEZZANINES BEYOND COLUMNS - Philadelphia Saving Fund Society, Twelfth & Market Streets, Philadelphia, Philadelphia County, PA

Observation of ground deformation associated with hydraulic fracturing and seismicity in the Western Canadian Sedimentary Basin

NASA Astrophysics Data System (ADS)

Kubanek, J.; Liu, Y.; Harrington, R. M.; Samsonov, S.

2017-12-01

In North America, the number of induced earthquakes related to fluid injection due to the unconventional recovery of oil and gas resources has increased significantly within the last five years. Recent studies demonstrate that InSAR is an effective tool to study surface deformation due to large-scale wastewater injection, and highlight the value of surface deformation monitoring with respect to understanding evolution of pore pressure and stress at depth - vital parameters to forecast fault reactivation, and thus, induced earthquakes. In contrast to earthquakes related to the injection of large amounts of wastewater, seismic activity related to the hydraulic fracturing procedure itself was, until recently, considered to play a minor role without significant hazard. In the Western Canadian Sedimentary Basin (WCSB), however, Mw>4 earthquakes have recently led to temporary shutdown of industrial injection activity, causing multi-million dollar losses to operators and raising safety concerns with the local population. Recent studies successfully utilize seismic data and modeling to link seismic activity with hydraulic fracturing in the WCSB. Although the study of surface deformation is likely the most promising tool for monitoring integrity of a well and to derive potential signatures prior to moderate or large induced events, InSAR has, to date, not been utilized to detect surface deformation related to hydraulic fracturing and seismicity. We therefore plan to analyze time-series of SAR data acquired between 1991 to present over two target sites in the WCSB that will enable the study of long- and short-term deformation. Since the conditions for InSAR are expected to be challenging due to spatial and temporal decorrelation, we have designed corner reflectors that will be installed at one target site to improve interferometric performance. The corner reflectors will be collocated with broadband seismometers and Trimble SeismoGeodetic Systems that simultaneously measure GNSS positioning and acceleration. We expect the joint data analysis of dense seismic and geodetic observations to give new insights about the correlation between surface deformation, fluid injection, and induced seismicity that can be used to assess the hazard potential of hydraulic fracturing in the WCSB.

3. VIEW OF WILLOW CREEK TRESTLE FROM CORNER BASELINE AVENUE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VIEW OF WILLOW CREEK TRESTLE FROM CORNER BASELINE AVENUE AND 185TH AVENUE, FACING NORTHEAST - Oregon Electric Railway Westside Corridor, Between Watson & 185th Avenues, Beaverton, Washington County, OR

14. CAR DUMP BUILDING, SOUTHWEST CORNER, VIEW SHOWING CABLE CAR ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. CAR DUMP BUILDING, SOUTHWEST CORNER, VIEW SHOWING CABLE CAR #20 BENEATH COAL CHUTES - Pennsylvania Railroad, Canton Coal Pier, Clinton Street at Keith Avenue (Canton area), Baltimore, Independent City, MD

38. Cafeteria, Dwing, building 500, looking northeast from southwest corner ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

38. Cafeteria, D-wing, building 500, looking northeast from southwest corner - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE

21. Threequarter view of northeast corner of Hwing, looking southwest ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. Three-quarter view of northeast corner of H-wing, looking southwest - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE

18. Threequarter view of southeast corner of Hwing, looking northwest ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. Three-quarter view of southeast corner of H-wing, looking northwest - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE

3. Southeast corner of Building 202, looking northwest from steps ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. Southeast corner of Building 202, looking northwest from steps on hillside near water tank. - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

FACADE OF THE CLUB MODERNE, SHOWING THE ORIGINAL CURVED CORNER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FACADE OF THE CLUB MODERNE, SHOWING THE ORIGINAL CURVED CORNER PROFILE AND TRI-COLOR CARRERE GLASS FACADE. - Anaconda Historic District, Club Moderne, 801 East Park Avenue, Anaconda, Deer Lodge County, MT

4. Cement and Plaster Warehouse, southeast corner, showing alterations; pent ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Cement and Plaster Warehouse, southeast corner, showing alterations; pent roof, window and door openings, siding, brick foundation sheathing. - Curtis Wharf, Cement & Plaster Warehouse, O & Second Streets, Anacortes, Skagit County, WA

Southwest corner, looking north U.S. Veterans Hospital, Jefferson Barracks, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Southwest corner, looking north - U.S. Veterans Hospital, Jefferson Barracks, Medical Officer in Charge Residence, VA Medical Center, Jefferson Barracks Division 1 Jefferson Barracks Drive, Saint Louis, Independent City, MO

Northeast corner, looking southwest U.S. Veterans Hospital, Jefferson Barracks, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Northeast corner, looking southwest - U.S. Veterans Hospital, Jefferson Barracks, Medical Officer in Charge Residence, VA Medical Center, Jefferson Barracks Division 1 Jefferson Barracks Drive, Saint Louis, Independent City, MO

6. SOUTHWEST CORNER OF BUILDING 8965 (SECURITY POLICE ENTRY CONTROL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. SOUTHWEST CORNER OF BUILDING 8965 (SECURITY POLICE ENTRY CONTROL BUILDING). - Loring Air Force Base, Alert Area, Southeastern portion of base, east of southern end of runway, Limestone, Aroostook County, ME

7. SOUTHEAST CORNER OF BUILDING 8965 (SECURITY POLICE ENTRY CONTROL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. SOUTHEAST CORNER OF BUILDING 8965 (SECURITY POLICE ENTRY CONTROL BUILDING). - Loring Air Force Base, Alert Area, Southeastern portion of base, east of southern end of runway, Limestone, Aroostook County, ME

20. DETAIL OF OFFICE FURNITURE IN NORTHEAST CORNER OF SECRETARIES' ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. DETAIL OF OFFICE FURNITURE IN NORTHEAST CORNER OF SECRETARIES' OFFICE ALONG NORTH SIDE OF FIRST FLOOR. VIEW TO NORTHEAST. - Boise Project, Boise Project Office, 214 Broadway, Boise, Ada County, ID

19. Detail of southeast corner of physical plant showing observation ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. Detail of southeast corner of physical plant showing observation lookout (view is looking northwest) - Skinner Meat Packing Plant, Main Plant, 6006 South Twenty-seventh Street, Omaha, Douglas County, NE

17. Oblique view of northwest corner of main plant looking ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. Oblique view of northwest corner of main plant looking southeast with railroad tracks in foreground - Skinner Meat Packing Plant, Main Plant, 6006 South Twenty-seventh Street, Omaha, Douglas County, NE

Northwest corner, showing arcade at ground level, and triple leaded ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Northwest corner, showing arcade at ground level, and triple leaded glass windows of bender room high on north elevation. - Stanford University Library, Stanford University, Palo Alto, Santa Clara County, CA

2. NORTHEAST CORNER OF LARD REFINERY (CONNECTING BUILDING ON THE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. NORTHEAST CORNER OF LARD REFINERY (CONNECTING BUILDING ON THE RIGHT) - Wilson's Oil House, Lard Refinery, & Edible Fats Factory, Lard Refinery, 2801 Southwest Fifteenth Street, Oklahoma City, Oklahoma County, OK

1. VIEW TO SOUTHEAST (NORTHWEST CORNER OF EDIBLE FATS FACTORY) ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. VIEW TO SOUTHEAST (NORTHWEST CORNER OF EDIBLE FATS FACTORY) - Wilson's Oil House, Lard Refinery, & Edible Fats Factory, Edible Fats Factory, 2801 Southwest Fifteenth Street, Oklahoma City, Oklahoma County, OK

3. VIEW TO SOUTHWEST (NORTHEAST CORNER OF EDIBLE FATS FACTORY) ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VIEW TO SOUTHWEST (NORTHEAST CORNER OF EDIBLE FATS FACTORY) - Wilson's Oil House, Lard Refinery, & Edible Fats Factory, Edible Fats Factory, 2801 Southwest Fifteenth Street, Oklahoma City, Oklahoma County, OK

18. NORTHEAST CORNER OF BUILDING 8990 (MASTER SURVEILLANCE ADN CONTROL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. NORTHEAST CORNER OF BUILDING 8990 (MASTER SURVEILLANCE ADN CONTROL TOWER). - Loring Air Force Base, Alert Area, Southeastern portion of base, east of southern end of runway, Limestone, Aroostook County, ME

17. SOUTHEAST CORNER OF BUILDING 8990 (MASTER SURVEILLANCE AND CONTROL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. SOUTHEAST CORNER OF BUILDING 8990 (MASTER SURVEILLANCE AND CONTROL TOWER). - Loring Air Force Base, Alert Area, Southeastern portion of base, east of southern end of runway, Limestone, Aroostook County, ME

122. BENCH SHOP, SOUTHWEST CORNER SHOWING WOOD BORING MACHINE. DOOR ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

122. BENCH SHOP, SOUTHWEST CORNER SHOWING WOOD BORING MACHINE. DOOR TO WOODSHOP ON RIGHT. - Gruber Wagon Works, Pennsylvania Route 183 & State Hill Road at Red Bridge Park, Bernville, Berks County, PA

1. Bombproof barracks, southwest corner from atop curtain wall, looking ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Bomb-proof barracks, southwest corner from atop curtain wall, looking easterly. Two lightning rods can be seen in background. - Fort Hamilton, Bomb-Proof Barracks, Rose Island, Newport, Newport County, RI

6. SOUTHWEST CORNER DETAIL (FRONT AND LEFT SIDE) SHOWING LOG ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. SOUTHWEST CORNER DETAIL (FRONT AND LEFT SIDE) SHOWING LOG JOINERY AND WEATHERBOARDING (copy negative, original 35 mm negative in field records) - Thomas Jefferson Walling Log Cabin, Henderson, Rusk County, TX

Perspective view toward the southwest from the corner of Line ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Perspective view toward the southwest from the corner of Line Street and Idaho Avenue - University of Idaho, University Classroom Building, Line Street between University Avenue & Idaho Avenue, Moscow, Latah County, ID

8. Detail, west corner, showing entrance fenestration, carved rafters supporting ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. Detail, west corner, showing entrance fenestration, carved rafters supporting metal-tiled pent roofs, tinted mortar; view to east. - Larco Building, 214 State Street, Santa Barbara, Santa Barbara County, CA

Electromagnetic backscattering by corner reflectors

NASA Technical Reports Server (NTRS)

Balanis, C. A.; Griesser, T.

1986-01-01

The Geometrical Theory of Diffraction (GTD), which supplements Geometric Optics (GO), and the Physical Theory of Diffraction (PTD), which supplements Physical Optics (PO), are used to predict the backscatter cross sections of dihedral corner reflectors which have right, obtuse, or acute included angles. These theories allow individual backscattering mechanisms of the dihedral corner reflectors to be identified and provide good agreement with experimental results in the azimuthal plane. The advantages and disadvantages of the geometrical and physical theories are discussed in terms of their accuracy, usefulness, and complexity. Numerous comparisons of analytical results with experimental data are presented. While physical optics alone is more accurate and more useful than geometrical optics alone, the combination of geometrical optics and geometrical diffraction seems to out perform physical optics and physical diffraction when compared with experimental data, especially for acute angle dihedral corner reflectors.

Application of Novel Lateral Tire Force Sensors to Vehicle Parameter Estimation of Electric Vehicles.

PubMed

Nam, Kanghyun

2015-11-11

This article presents methods for estimating lateral vehicle velocity and tire cornering stiffness, which are key parameters in vehicle dynamics control, using lateral tire force measurements. Lateral tire forces acting on each tire are directly measured by load-sensing hub bearings that were invented and further developed by NSK Ltd. For estimating the lateral vehicle velocity, tire force models considering lateral load transfer effects are used, and a recursive least square algorithm is adapted to identify the lateral vehicle velocity as an unknown parameter. Using the estimated lateral vehicle velocity, tire cornering stiffness, which is an important tire parameter dominating the vehicle's cornering responses, is estimated. For the practical implementation, the cornering stiffness estimation algorithm based on a simple bicycle model is developed and discussed. Finally, proposed estimation algorithms were evaluated using experimental test data.

A new numerical approach for uniquely solvable exterior Riemann-Hilbert problem on region with corners

NASA Astrophysics Data System (ADS)

Zamzamir, Zamzana; Murid, Ali H. M.; Ismail, Munira

2014-06-01

Numerical solution for uniquely solvable exterior Riemann-Hilbert problem on region with corners at offcorner points has been explored by discretizing the related integral equation using Picard iteration method without any modifications to the left-hand side (LHS) and right-hand side (RHS) of the integral equation. Numerical errors for all iterations are converge to the required solution. However, for certain problems, it gives lower accuracy. Hence, this paper presents a new numerical approach for the problem by treating the generalized Neumann kernel at LHS and the function at RHS of the integral equation. Due to the existence of the corner points, Gaussian quadrature is employed which avoids the corner points during numerical integration. Numerical example on a test region is presented to demonstrate the effectiveness of this formulation.

Prehistoric mitochondrial DNA of domesticate animals supports a 13th century exodus from the northern US southwest

PubMed Central

Judd, Kathleen; Monroe, Cara; Hilldorfer, Lindsay; Cordray, Connor; Schad, Rebecca; Reams, Erin

2017-01-01

The 13th century Puebloan depopulation of the Four Corners region of the US Southwest is an iconic episode in world prehistory. Studies of its causes, as well as its consequences, have a bearing not only on archaeological method and theory, but also social responses to climate change, the sociology of social movements, and contemporary patterns of cultural diversity. Previous research has debated the demographic scale, destinations, and impacts of Four Corners migrants. Much of this uncertainty stems from the substantial differences in material culture between the Four Corners vs. hypothesized destination areas. Comparable biological evidence has been difficult to obtain due to the complete departure of farmers from the Four Corners in the 13th century CE and restrictions on sampling human remains. As an alternative, patterns of genetic variation among domesticated species were used to address the role of migration in this collapse. We collected mitochondrial haplotypic data from dog (Canis lupus familiaris) and turkey (Meleagris gallopavo) remains from archaeological sites in the most densely-populated portion of the Four Corners region, and the most commonly proposed destination area for that population under migration scenarios. Results are consistent with a large-scale migration of humans, accompanied by their domestic turkeys, during the 13th century CE. These results support scenarios that suggest contemporary Pueblo peoples of the Northern Rio Grande are biological and cultural descendants of Four Corners populations. PMID:28746407

Proyecto MercadoFRESCO: a multi-level, community-engaged corner store intervention in East Los Angeles and Boyle Heights.

PubMed

Ortega, Alexander N; Albert, Stephanie L; Sharif, Mienah Z; Langellier, Brent A; Garcia, Rosa Elena; Glik, Deborah C; Brookmeyer, Ron; Chan-Golston, Alec M; Friedlander, Scott; Prelip, Michael L

2015-04-01

Urban food swamps are typically situated in low-income, minority communities and contribute to overweight and obesity. Changing the food landscape in low income and underserved communities is one strategy to combat the negative health consequences associated with the lack of access to healthy food resources and an abundance of unhealthy food venues. In this paper, we describe Proyecto MercadoFRESCO (Fresh Market Project), a corner store intervention project in East Los Angeles and Boyle Heights in California that used a multi-level approach with a broad range of community, business, and academic partners. These are two neighboring, predominantly Latino communities that have high rates of overweight and obesity. Located in these two communities are approximately 150 corner stores. The project used a community-engaged approach to select, recruit, and convert four corner stores, so that they could become healthy community assets in order to improve residents' access to and awareness of fresh and affordable fruits and vegetables in their immediate neighborhoods. We describe the study framework for the multi-level intervention, which includes having multiple stakeholders, expertise in corner store operations, community and youth engagement strategies, and social marketing campaigns. We also describe the evaluation and survey methodology to determine community and patron impact of the intervention. This paper provides a framework useful to a variety of public health stakeholders for implementing a community-engaged corner store conversion, particularly in an urban food swamp.