Combined effect of matrix cracking and stress-free edge on delamination

NASA Technical Reports Server (NTRS)

Salpekar, Satish A.; O'Brien, T. K.

1991-01-01

The effect of the stress-free edge on the growth of local delaminations initiating from a matrix crack in (O sub 2/90 sub 4) sub s and (+/- 45.90 sub 4) sub s glass epoxy laminates is investigated using 3D finite element analysis. The presence of high interlaminar normal stresses at the intersection (corner) of the matrix crack with the stress-free edge, suggests that a mode I delamination may initiate at the corners. The strain energy release rates (G) were calculated by modeling a uniform through-width delamination and two inclined delaminations at 10.6 deg and 45 deg to the matrix crack. All components of G have high values near the free edges. The mode I component of G is high at small delamination length and becomes zero for a delamination length of one-ply thickness. The total G values near the free edge agreed well with previously derived closed form solution. The quasi-3D solutions agreed well with the 3D interior solutions.

Calculating corner singularities by boundary integral equations.

PubMed

Shi, Hualiang; Lu, Ya Yan; Du, Qiang

2017-06-01

Accurate numerical solutions for electromagnetic fields near sharp corners and edges are important for nanophotonics applications that rely on strong near fields to enhance light-matter interactions. For cylindrical structures, the singularity exponents of electromagnetic fields near sharp edges can be solved analytically, but in general the actual fields can only be calculated numerically. In this paper, we use a boundary integral equation method to compute electromagnetic fields near sharp edges, and construct the leading terms in asymptotic expansions based on numerical solutions. Our integral equations are formulated for rescaled unknown functions to avoid unbounded field components, and are discretized with a graded mesh and properly chosen quadrature schemes. The numerically found singularity exponents agree well with the exact values in all the test cases presented here, indicating that the numerical solutions are accurate.

Acoustic Scattering from Corners, Edges and Circular Cones

NASA Astrophysics Data System (ADS)

Elschner, Johannes; Hu, Guanghui

2018-05-01

Consider the time-harmonic acoustic scattering from a bounded penetrable obstacle imbedded in an isotropic homogeneous medium. The obstacle is supposed to possess a circular conic point or an edge point on the boundary in three dimensions and a planar corner point in two dimensions. The opening angles of cones and edges are allowed to be any number in {(0,2π)π}. We prove that such an obstacle scatters any incoming wave non-trivially (that is, the far field patterns cannot vanish identically), leading to the absence of real non-scattering wavenumbers. Local and global uniqueness results for the inverse problem of recovering the shape of penetrable scatterers are also obtained using a single incoming wave. Our approach relies on the singularity analysis of the inhomogeneous Laplace equation in a cone.

Distribution of contact loads over the flank-land of the cutter with a rounded cutting edge

NASA Astrophysics Data System (ADS)

Kozlov, V.; Gerasimov, A.; Kim, A.

2016-04-01

In this paper, contact conditions between a tool and a workpiece material for wear-simulating turning by a cutter with a sharp-cornered edge and with a rounded cutting edge are analysed. The results of the experimental study of specific contact load distribution over the artificial flank wear-land of the cutter in free orthogonal turning of the disk from titanium alloy (Ti6Al2Mo2Cr), ductile (63Cu) and brittle (57Cu1Al3Mn) brasses are described. Investigations were carried out by the method of ‘split cutter’ and by the method of the artificial flank-land of variable width. The experiments with a variable feed rate and a cutting speed show that in titanium alloy machining with a sharp-cornered cutting edge the highest normal contact load (σh max = 3400…2200 MPa) is observed immediately at the cutting edge, and the curve has a horizontal region with the length of 0.2… 0.6 mm. At a distance from the cutting edge, the value of specific normal contact load is dramatically reduced to 1100…500 MPa. The character of normal contact load for a rounded cutting edge is different -it is uniform, and its value is approximately 2 times smaller compared to machining with a sharp-cornered cutting edge. In author’s opinion it is connected with generation of a seizure zone in a chip formation region and explains the capacity of highly worn-out cutting tools for titanium alloys machining. The paper analyses the distribution of tangential contact loads over the flank land, which pattern differs considerably for machining with a sharp-cornered edge and with a rounded cutting edge. Abbreviation and symbols: m/s - meter per second (cutting speed v); mm/r - millimeter per revolution (feed rate f); MPa - mega Pascal (specific contact load as a stress σ or τ) hf - the width of the flank wear land (chamfer) of the cutting tool, flank wear land can be natural or artificial like the one in this paper [mm]; xh - distance from the cutting edge on the surface of the flank-land [mm]; σh - normal specific contact load on the flank land [MPa]; τh - tangential (shear) specific contact load on the flank land [MPa]; HSS - high speed steel (material of cutting tool); Py - radial component of cutting force [N]; Py r - radial component of cutting force on the rake face [N]; Pz - tangential component of cutting force [N]; γ - rake angle of the cutting tool [°] α - clearance angle of the sharp cutting tool [°] αh - clearance angle of the flank wear land [°] ρ - rounding off radius of the cutting edge [mm]; b - width of the machined disk [mm].

Matching Aerial Images to 3D Building Models Using Context-Based Geometric Hashing

PubMed Central

Jung, Jaewook; Sohn, Gunho; Bang, Kiin; Wichmann, Andreas; Armenakis, Costas; Kada, Martin

2016-01-01

A city is a dynamic entity, which environment is continuously changing over time. Accordingly, its virtual city models also need to be regularly updated to support accurate model-based decisions for various applications, including urban planning, emergency response and autonomous navigation. A concept of continuous city modeling is to progressively reconstruct city models by accommodating their changes recognized in spatio-temporal domain, while preserving unchanged structures. A first critical step for continuous city modeling is to coherently register remotely sensed data taken at different epochs with existing building models. This paper presents a new model-to-image registration method using a context-based geometric hashing (CGH) method to align a single image with existing 3D building models. This model-to-image registration process consists of three steps: (1) feature extraction; (2) similarity measure; and matching, and (3) estimating exterior orientation parameters (EOPs) of a single image. For feature extraction, we propose two types of matching cues: edged corner features representing the saliency of building corner points with associated edges, and contextual relations among the edged corner features within an individual roof. A set of matched corners are found with given proximity measure through geometric hashing, and optimal matches are then finally determined by maximizing the matching cost encoding contextual similarity between matching candidates. Final matched corners are used for adjusting EOPs of the single airborne image by the least square method based on collinearity equations. The result shows that acceptable accuracy of EOPs of a single image can be achievable using the proposed registration approach as an alternative to a labor-intensive manual registration process. PMID:27338410

33 CFR 334.1310 - Lutak Inlet, Alaska; restricted areas.

Code of Federal Regulations, 2010 CFR

2010-07-01

... follows: Beginning at the water's edge 900 feet northwest of the centerline of the landward end of the POL...'s edge at a point approximately 720 feet from the most southwest corner of the seaward end of the POL dock; thence along the water's edge to the point of beginning. (ii) The area will be marked at...

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).

View of southeastern Washington State

NASA Image and Video Library

1973-08-30

SL3-22-0214 (July-September 1973) --- A vertical view of southeastern Washington State as photographed from Earth orbit by one of the six lenses of the Itek-furnished S190-A Multispectral Photographic Facility Experiment aboard the Skylab space station. The Snake River flows into the Columbia River in the most southerly corner of the picture. The Wallula Lake is below the junction of the two rivers. The Yakima Valley is at the southwestern edge of the photograph. The Columbia Basin is in the center of the picture. The Cascade Range extends across the northwest corner of the photograph. This picture was taken with type SO-356 regular color film. The S190-A experiment is part of the Earth Resources Experiments Package. Federal agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce, Interior, the Environmental Protection Agency and the Corps of Engineers. All EREP photography is available to the public through the Department of Interior?s Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota, 57198. Photo credit: NASA

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.

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.

Investigation of stress concentration at corner points for orthotropic plate bending problem

NASA Astrophysics Data System (ADS)

Vasilyan, N. G.

2018-04-01

This article deals with the bending problem for an orthotropic semi-infinite plate strip when three edges of the plate are hinged and the fourth edge goes to infinity. The plate is loaded with distributed load of intensity q(y). A. Nadai’s approach is applied, which says that to obtain the solution at a far distance from the edge, it is necessary to solve the problem of cylindrical bending. The generalized shearing forces on the fixed edge are investigated.

Wall shear stress measurement in blade end-wall corner region

NASA Technical Reports Server (NTRS)

Bhargava, R.; Raj, R.; Boldman, D. R.

1987-01-01

The magnitude and the direction of wall shear stress and surface pressure in the blade end-wall corner region were investigated. The measurements were obtained on a specially designed Preston tube, the tip of which could be concentrically rotated about its axis of rotation at the measurement location. The magnitude of wall shear stress in the vicinity of the corner was observed to increase significantly (170 percent) compared to its far-upstream value; the increase was consistently higher on the blade surface compared to the value on the plate surface of the blade end-wall corner. On both surfaces in the blade end-wall corner, the variation of the wall shear stress direction was found to be more predominant in the vicinity of the blade leading-edge location. The trend of the measured wall shear stress direction showed good agreement with the limiting streamline directions obtained from the flow visualization studies.

Transformation-optics description of plasmonic nanostructures containing blunt edges/corners: from symmetric to asymmetric edge rounding.

PubMed

Luo, Yu; Lei, Dang Yuan; Maier, Stefan A; Pendry, John B

2012-07-24

The sharpness of corners/edges can have a large effect on the optical responses of metallic nanostructures. Here we deploy the theory of transformation optics to analytically investigate a variety of blunt plasmonic structures, including overlapping nanowire dimers and crescent-shaped nanocylinders. These systems are shown to support several discrete optical modes, whose energy and line width can be controlled by tuning the nanoparticle geometry. In particular, the necessary conditions are highlighted respectively for the broadband light absorption effect and the invisibility dips that appear in the radiative spectrum. More detailed discussions are provided especially with respect to the structures with asymmetric edge rounding. These structures can support additional subradiant modes, whose interference with the neighboring dipolar modes results in a rapid change of the scattering cross-section, similar to the phenomenon observed in plasmonic Fano resonances. Finite element numerical calculations are also performed to validate the analytical predictions. The physical insights into blunt nanostructures presented in this work may be of great interest for the design of broadband light-harvesting devices, invisible and noninvasive biosensors, and slowing-light devices.

The St. Elias orogen as an early stage in the development of indentor corners: Initial results from the STEEP project

NASA Astrophysics Data System (ADS)

Pavlis, T. L.; Bruhn, R. L.; Koons, P.; Berger, A.; Spotila, J.; Barker, A.; Chapman, J.; Doser, D.; Pavlis, G.

2006-12-01

The actively deforming St. Elias orogen of southern Alaska is developed at the transition between the Aleutian trench and the Queen Charlottes transform, and has produced a "one sided" indentor corner as the collided block has been carried obliquely into the subduction-transform transition. A distinctive feature generated within this evolving corner is a 90o bend in the suture at the western edge of the orogen that is associated with a refolding of earlier thin-skinned fold-thrust systems in the collided block. The refolding is recognizable in the area between the bent suture and a major glacial valley, the Bering Glacier, but is absent to the east. Bruhn et al. (2004, GSAB) used this observation to infer an active structure along the Bering Glacier, and speculated that the refolding may be active. New data collected as part of the St. Elias Erosion and tectonics Project (STEEP) provides support for this hypothesis from two observations: 1) clear evidence that many of the hundreds of surface ruptures in this region represent fault-scarps-- probably representing fold-related, bedding- plane slip during refolding; and 2) extremely young (locally <500Ka) U-Th-He apatite cooling ages just west of the Bering Glacier are consistent with the hypothesis of an active structure along the glacial valley. However, young cooling ages to the east of the Bering Glacier as well as geomorphology suggest that at least one of the fold-thrust belt structures is also active, indicating that the interplay of active faults is complex. Additional support for active deformation along the Bering Glacier comes from the spatial distribution of seismicity between the Bering Glacier and Bagley icefield and these observations should be further constrained as data are obtained from the new STEEP broadband seismic network in the area. Analog (sand) and numerical models suggest that this type of feature can originate as the indentor is driven into the corner through a variable vertical axis vorticity; clockwise along the transform boundary and counterclockwise at the outboard edge of the indentor. A secondary complication in this system, however, is its constriction as the collided block is carried obliquely into an acute-angle corner. We speculate here that the development of an active structure along the Bering Glacier is not coincidental. Some type of structure would be required to accommodate differential motion between the refolding domain and areas to the east where more normal convergence is occurring, and the spatial position of the boundary may be controlled by the position of a deep glacial valley within the orogen. Once the structure is formed, focused glacial erosion along the valley can serve to rapidly evacuate mass from the orogen and over time could easily develop into an "aneurism" analogous to the Himalayan syntaxes.

An experimental study of near wall flow parameters in the blade end-wall corner region

NASA Technical Reports Server (NTRS)

Bhargava, Rakesh K.; Raj, Rishi S.

1989-01-01

The near wall flow parameters in the blade end-wall corner region is investigated. The blade end-wall corner region was simulated by mounting an airfoil section (NACA 65-015 base profile) symmetric blades on both sides of the flat plate with semi-circular leading edge. The initial 7 cm from the leading edge of the flat plate was roughened by gluing No. 4 floor sanding paper to artificially increase the boundary layer thickness on the flat plate. The initial flow conditions of the boundary layer upstream of the corner region are expected to dictate the behavior of flow inside the corner region. Therefore, an experimental investigation was extended to study the combined effect of initial roughness and increased level of free stream turbulence on the development of a 2-D turbulent boundary layer in the absence of the blade. The measurement techniques employed in the present investigation included, the conventional pitot and pitot-static probes, wall taps, the Preston tube, piezoresistive transducer and the normal sensor hot-wire probe. The pitot and pitot-static probes were used to obtain mean velocity profile measurements within the boundary layer. The measurements of mean surface static pressure were obtained with the surface static tube and the conventional wall tap method. The wall shear vector measurements were made with a specially constructed Preston tube. The flush mounted piezoresistive type pressure transducer were employed to measure the wall pressure fluctuation field. The velocity fluctuation measurements, used in obtaining the wall pressure-velocity correlation data, were made with normal single sensor hot-wire probe. At different streamwise stations, in the blade end-wall corner region, the mean values of surface static pressure varied more on the end-wall surface in the corner region were mainly caused by the changes in the curvature of the streamlines. The magnitude of the wall shear stress in the blade end-wall corner region increased significantly in the close vicinity of the corner line. The maximum value of the wall shear stress and its location from the corner line, on both the surfaces forming the corner region, were observed to change along the corner. These observed changes in the maximum values of the wall shear stress and its location from the corner line could be associated with the stretching and attenuation of the horseshoe vortex. The wall shear stress vectors in the blade end-wall corner region were observed to be more skewed on the end-wall surface as compared to that on the blade surface. The differences in the wall shear stress directions obtained with the Preston tube and flow visualization method were within the range in which the Preston tube was found to be insensitive to the yaw angle.

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.

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%.

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.

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

The visual system prioritizes locations near corners of surfaces (not just locations near a corner).

PubMed

Bertamini, Marco; Helmy, Mai; Bates, Daniel

2013-11-01

When a new visual object appears, attention is directed toward it. However, some locations along the outline of the new object may receive more resources, perhaps as a consequence of their relative importance in describing its shape. Evidence suggests that corners receive enhanced processing, relative to the straight edges of an outline (corner enhancement effect). Using a technique similar to that in an original study in which observers had to respond to a probe presented near a contour (Cole et al. in Journal of Experimental Psychology: Human Perception and Performance 27:1356-1368, 2001), we confirmed this effect. When figure-ground relations were manipulated using shaded surfaces (Exps. 1 and 2) and stereograms (Exps. 3 and 4), two novel aspects of the phenomenon emerged: We found no difference between corners perceived as being convex or concave, and we found that the enhancement was stronger when the probe was perceived as being a feature of the surface that the corner belonged to. Therefore, the enhancement is not based on spatial aspects of the regions in the image, but critically depends on figure-ground stratification, supporting the link between the prioritization of corners and the representation of surface layout.

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.

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.

Northeastern Exterior, Northwestern Exterior, & Southwestern Exterior Elevations, Northeastern Interior, ...

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

Northeastern Exterior, Northwestern Exterior, & Southwestern Exterior Elevations, Northeastern Interior, Southeastern Interior, & Southwestern Interior Elevations, Floor Plan, and Eastern Corner Detail - Manatoc Reservation, Vale Edge Adirondack, 1075 Truxell Road, Peninsula, Summit County, OH

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.

Rural Critical Care Nurse Training Project--Four Corners Area, November 14, 1975.

ERIC Educational Resources Information Center

New Mexico Regional Medical Program, Albuquerque.

Project objectives were to train 10 nurses from hospitals in the Four Corners Area in rural critical care nursing, to have a training director organize and coordinate the project, and to utilize the replacement nurse concept. The course curriculum was determined through a needs assessment survey conducted by a team of health professionals from…

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

Core logs from five holes near Kramer, in the Mojave Desert, California

USGS Publications Warehouse

Benda, William K.; Erd, Richard C.; Smith, Ward C.

1958-01-01

In 1957, five test holes were drilled near Kramer, California, in =he western Mojave Desert. The drill sites are in topographic basins where gravimetric and geologic surveys indicated the presence, beneath alluvium, of a thick section of Quaternary and Tertiary sedimentary and volcanic rocks. Two holes which were deeper tests at sites drilled in 1954 cored only silts, sands and gravels: Four Corners test hole No. 1 was drilled in sec. 20, T. I0 N., R. 6 W., to a depth of 3,500 feet. Four Corners No. 2, in sec. 5, T. I0 N., R. 8 W., was drilled to 2,328 feet. Three holes which were drilled at new sites north of the intersection of U. S. Highways 395 and 466, locally known as Four Corners, encountered colemanite-bearing sediments. The locations and total depths of these holes are as follows: Four Corners No. 3, sec. T. 11 N., R. 6 W., depth 2,568 feet; Four Corners No. 4, near northern edge of sec. 30, T. ll N., R. 6 W., depth 3,500 feet; Four Corners No. 5, near southern edge of sec. 30, depth 1,604 feet. The sections of rocks encountered in these three holes are similar. In each, the colemanite is in fine-grained sediments that lie below sands and gravels, which are about 600 to 800 feet thick, and are underlain by sandstones and conglomerates. Colemanite is most abundant in the cores from Four Corners to hole No. 5, particularly in the 76 feet of core recovered between depths of 1,051 and 1,131 feet. Chemical analysis shows that in this section of core the average content of B203 is above 14 percent. In addition to colemanite, the cores contain sulfides of arsenic, an unusual iron sulfide, and zeolites. This mineralogy of the colemanite-bearing sediments north of Four Corners, together with the general lake bed lithology and the occurrence as a tilted section of beds below sands and gravels, supports correlation with the upper or marginal parts of the borate-bearin8 sediments at the Kramer borate mining district, which have similar features. There is, however, no evidence that any beds are exactly equivalent in age.

Quasiconvexity at the Boundary and the Nucleation of Austenite

NASA Astrophysics Data System (ADS)

Ball, J. M.; Koumatos, K.

2016-01-01

Motivated by experimental observations of H. Seiner et al., we study the nucleation of austenite in a single crystal of a CuAlNi shape-memory alloy stabilized as a single variant of martensite. In the experiments the nucleation process was induced by localized heating and it was observed that, regardless of where the localized heating was applied, the nucleation points were always located at one of the corners of the sample—a rectangular parallelepiped in the austenite. Using a simplified nonlinear elasticity model, we propose an explanation for the location of the nucleation points by showing that the martensite is a local minimizer of the energy with respect to localized variations in the interior, on faces and edges of the sample, but not at some corners, where a localized microstructure, involving austenite and a simple laminate of martensite, can lower the energy. The result for the interior, faces and edges is established by showing that the free-energy function satisfies a set of quasiconvexity conditions at the stabilized variant in the interior, faces and edges, respectively, provided the specimen is suitably cut.

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...

Electrical control of flying spin precession in chiral 1D edge states

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

Nakajima, Takashi; Komiyama, Susumu; Lin, Kuan-Ting

2013-12-04

Electrical control and detection of spin precession are experimentally demonstrated by using spin-resolved edge states in the integer quantum Hall regime. Spin precession is triggered at a corner of a biased metal gate, where electron orbital motion makes a sharp turn leading to a nonadiabatic change in the effective magnetic field via spin-orbit interaction. The phase of precession is controlled by the group velocity of edge-state electrons tuned by gate bias voltage: Spin-FET-like coherent control of spin precession is thus realized by all-electrical means.

Real Time Corner Detection for Miniaturized Electro-Optical Sensors Onboard Small Unmanned Aerial Systems

PubMed Central

Forlenza, Lidia; Carton, Patrick; Accardo, Domenico; Fasano, Giancarmine; Moccia, Antonio

2012-01-01

This paper describes the target detection algorithm for the image processor of a vision-based system that is installed onboard an unmanned helicopter. It has been developed in the framework of a project of the French national aerospace research center Office National d’Etudes et de Recherches Aérospatiales (ONERA) which aims at developing an air-to-ground target tracking mission in an unknown urban environment. In particular, the image processor must detect targets and estimate ground motion in proximity of the detected target position. Concerning the target detection function, the analysis has dealt with realizing a corner detection algorithm and selecting the best choices in terms of edge detection methods, filtering size and type and the more suitable criterion of detection of the points of interest in order to obtain a very fast algorithm which fulfills the computation load requirements. The compared criteria are the Harris-Stephen and the Shi-Tomasi, ones, which are the most widely used in literature among those based on intensity. Experimental results which illustrate the performance of the developed algorithm and demonstrate that the detection time is fully compliant with the requirements of the real-time system are discussed. PMID:22368499

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.

View of Central Texas as seen from Apollo 9

NASA Technical Reports Server (NTRS)

1969-01-01

Central Texas area as photographed from the Apollo 9 spacecraft during its earth-orbital mission. Interstate 35 runs from Austin (right center edge of pictures) to Waco (near bottom left corner). Also, visible are the cities of Georgetown, Taylor, Temple and Killeen. The Colorado River runs through Austin. The Brazos River flows through Waco. Lake Travis is upstream from Austin. Lake Whitney is at bottom left corner of picture. The Belton Reservoir is near bottom center. The lake formed by the dam on the Lampasas River near Belton is also clearly visible.

The Role of Connectivity on Electronic Properties of Lead Iodide Perovskite-Derived Compounds

PubMed Central

2017-01-01

We use a layered solution crystal growth method to synthesize high-quality single crystals of two different benzylammonium lead iodide perovskite-like organic/inorganic hybrids. The well-known (C6H5CH2NH3)2PbI4 phase is obtained in the form of bright orange platelets, with a structure comprised of single ⟨100⟩-terminated sheets of corner-sharing PbI6 octahedra separated by bilayers of the organic cations. The presence of water during synthesis leads to formation of a novel minority phase that crystallizes in the form of nearly transparent, light yellow bar-shaped crystals. This phase adopts the monoclinic space group P21/n and incorporates water molecules, with structural formula (C6H5CH2NH3)4Pb5I14·2H2O. The crystal structure consists of ribbons of edge-sharing PbI6 octahedra separated by the organic cations. Density functional theory calculations including spin–orbit coupling show that these edge-sharing PbI6 octahedra cause the band gap to increase with respect to corner-sharing PbI6 octahedra in (C6H5CH2NH3)2PbI4. To gain systematic insight, we model the effect of the connectivity of PbI6 octahedra on the band gap in idealized lead iodide perovskite-derived compounds. We find that increasing the connectivity from corner-, via edge-, to face-sharing causes a significant increase in the band gap. This provides a new mechanism to tailor the optical properties in organic/inorganic hybrid compounds. PMID:28677956

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...

Graphene microsheets enter cells through spontaneous membrane penetration at edge asperities and corner sites

PubMed Central

Li, Yinfeng; Yuan, Hongyan; von dem Bussche, Annette; Creighton, Megan; Hurt, Robert H.; Kane, Agnes B.; Gao, Huajian

2013-01-01

Understanding and controlling the interaction of graphene-based materials with cell membranes is key to the development of graphene-enabled biomedical technologies and to the management of graphene health and safety issues. Very little is known about the fundamental behavior of cell membranes exposed to ultrathin 2D synthetic materials. Here we investigate the interactions of graphene and few-layer graphene (FLG) microsheets with three cell types and with model lipid bilayers by combining coarse-grained molecular dynamics (MD), all-atom MD, analytical modeling, confocal fluorescence imaging, and electron microscopic imaging. The imaging experiments show edge-first uptake and complete internalization for a range of FLG samples of 0.5- to 10-μm lateral dimension. In contrast, the simulations show large energy barriers relative to kBT for membrane penetration by model graphene or FLG microsheets of similar size. More detailed simulations resolve this paradox by showing that entry is initiated at corners or asperities that are abundant along the irregular edges of fabricated graphene materials. Local piercing by these sharp protrusions initiates membrane propagation along the extended graphene edge and thus avoids the high energy barrier calculated in simple idealized MD simulations. We propose that this mechanism allows cellular uptake of even large multilayer sheets of micrometer-scale lateral dimension, which is consistent with our multimodal bioimaging results for primary human keratinocytes, human lung epithelial cells, and murine macrophages. PMID:23840061

Enabler operator station

NASA Technical Reports Server (NTRS)

Bailey, Andrea; Kietzman, John; King, Shirlyn; Stover, Rae; Wegner, Torsten

1992-01-01

The objective of this project was to design an onboard operator station for the conceptual Lunar Work Vehicle (LWV). The LWV would be used in the colonization of a lunar outpost. The details that follow, however, are for an Earth-bound model. The operator station is designed to be dimensionally correct for an astronaut wearing the current space shuttle EVA suit (which include life support). The proposed operator station will support and restrain an astronaut as well as to provide protection from the hazards of vehicle rollover. The threat of suit puncture is eliminated by rounding all corners and edges. A step-plate, located at the front of the vehicle, provides excellent ease of entry and exit. The operator station weight requirements are met by making efficient use of rigid members, semi-rigid members, and woven fabrics.

View of Central Texas as seen from Apollo 9

NASA Image and Video Library

1969-03-09

AS09-22-3341 (3-13 March 1969) --- Central Texas area as photographed from the Apollo 9 spacecraft during its Earth-orbital mission. Interstate 35 runs from Austin (right center edge of picture) to Waco (near bottom left corner). Also visible are the cities of Georgetown, Taylor, Temple and Killeen. The Colorado River runs through Austin. The Brazos River flows through Waco. Lake Travis is upstream from Austin. Lake Whitney is at bottom left corner of picture. The Belton Reservoir is near bottom center. The lake formed by the dam on the Lampasas River near Belton is also clearly visible.

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.

Proyecto MercadoFRESCO: A Multi-level, Community-Engaged Corner Store Intervention in East Los Angeles and Boyle Heights

PubMed Central

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.

2014-01-01

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. PMID:25209600

4. Aerial view of turnpike path running through center of ...

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

4. Aerial view of turnpike path running through center of photograph along row of trees. South edge of original alignment visible at left at cluster of white trailers. North edge of original alignment visible at right at the W.K. Smith house (HABS No. NY-6356-A) at the top right corner. Migel mansion visible on ridgetop at right-center of photograph, surrounded by trees. View looking west. - Orange Turnpike, Parallel to new Orange Turnpike, Monroe, Orange County, NY

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.

Slylab (SL)-3 View - North Central Wyoming (WY) - Southern Montana (MT)

NASA Image and Video Library

1973-08-15

S73-35081 (July-September 1973) --- A view of approximately 3,600 square miles of north central Wyoming and southern Montana is seen in this Skylab 3 Earth Resources Experiments Package S190-B (five-inch Earth terrain camera) photograph taken from the Skylab space station in Earth orbit. The Big Horn River following northward crosses between the northwest trending Big Horn Mountains and the Pryor Mountains. Yellowtail Reservoir, named after a former chief of the Crow Indian tribe in the center of the picture is impounded by a dam across the small rectangular crop area along the Big Horn River (upper right) and the strip farming (yellow) practiced on the rolling hill along the Big Horn River and its tributaries (upper left corner and right edge). The low sun angle enhances the structural features of the mountains as well as the drainage patterns in the adjacent basins. Rock formation appears in this color photograph as they would to the eye from this altitude. The distinctive redbeds can be traced along the front of the Pryor Mountains and indicate the folding that occurred during mountain building. EREP investigators, Dr. Houston of the University of Wyoming and Dr. Hoppin of the University of Iowa, will analyze the photograph and use the results in geological mapping and mineral resource studies. Lowell, Wyoming (lower left corner) and Hardin, Montana (upper right corner) can be recognized. Federal agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce, Interior, the Environmental Protection Agency and the Corps of Engineers. All EREP photography is available to the public through the Department of Interior?s Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota, 57198. (Alternate number SL3-86-337) Photo credit: NASA

MTR MAIN FLOOR. NEUTRON TUNNEL (SPANNED BY STILELIKE STEPS) PROJECTS ...

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

MTR MAIN FLOOR. NEUTRON TUNNEL (SPANNED BY STILE-LIKE STEPS) PROJECTS FROM THE SOUTHEAST CORNER OF THE MTR TOWARD SOUTHEAST CORNER OF BUILDING, WHERE SHIELDING BLOCKS BEGIN TO SURROUND THE TUNNEL AS IT NEARS DETECTING INSTRUMENTS NEAR THE BUILDING WALL. GEAR RELATED TO CRYSTAL NEUTRON SPECTROMETER IS IN FOREGROUND SURROUNDED BY SHIELDING. DATA CONSOLES ARE AT MID-LEVEL OF EAST FACE. OTHER WORK PROCEEDS ON TOP OF AND ELSEWHERE AROUND REACTOR. NOTE TOOLS HANGING AGAINST SOUTHEAST CORNER, USED TO CHANGE FUEL ELEMENTS AND OTHER REACTOR ITEMS DURING REFUELING CYCLES. INL NEGATIVE NO. 10439. Unknown Photographer, 4/20/1954 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

An ideal clamping analysis for a cross-ply laminate

NASA Technical Reports Server (NTRS)

Valisetty, R. R.; Murthy, P. L. N.; Rehfield, L. W.

1988-01-01

Different elementary clamping models are discussed for a three layer crossply laminate to study the sensitivity of clamping to the definition of cross-sectional rotation. All of these models leave a considerable residual warping at the edges. Using a complimentary energy principle and principle of superposition, an analysis is conducted to reduce this residual warping. This led to the identification of exact interior solution corresponding to the ideal clamping. This study also suggests a presence of stress singularities at the corners and between different layers near the fixed edge.

Rotary seal with enhanced lubrication and contaminant flushing

DOEpatents

Dietle, Lannie L.

2000-01-01

A resilient, ring shaped interference-type hydrodynamic rotary seal having waves on the lubricant side which provide increased film thickness and flushing action by creating contact pressure induced angulated restrictions formed by abrupt restrictive diverters. The angulated restrictions are defined by projecting ridges, corners at the trailing edge of the waves, or simply by use of a converging shape at the trailing edge of the waves which is more abrupt than the gently converging hydrodynamic inlet shape at the leading edge of the waves. The abrupt restrictive diverter performs two functions; a restricting function and a diverting function. The angulated restrictions cause a local film thickness restriction which produces a damming effect preventing a portion of the lubricant from leaking out of the dynamic sealing interface at the trailing edge of the wave, and results in a much thicker lubricant film thickness under the waves. This contributes to more film thickness in the remainder of the dynamic sealing interface toward the environment because film thickness tends to decay gradually rather than abruptly due to the relative stiffness of the seal material. Because of the angle of the abrupt restrictive diverter relative to the relative rotation direction, in conjunction with the restriction or damming effect, a strong diverting action is produced which pumps lubricant across the dynamic sealing interface toward the environment. The lubricant diversion is caused by the component of the rotational velocity tangent to the abrupt restrictive diverter. The component of rotational velocity normal to the abrupt restrictive diverter causes a portion of the lubricant film to be pumped past the abrupt restrictive diverter, thereby assuring adequate lubrication thereof.

Manufacturability: from design to SPC limits through "corner-lot" characterization

NASA Astrophysics Data System (ADS)

Hogan, Timothy J.; Baker, James C.; Wesneski, Lisa; Black, Robert S.; Rothenbury, Dave

2004-12-01

Texas Instruments" Digital Micro-mirror Device, is used in a wide variety of optical display applications ranging from fixed and portable projectors to high-definition television (HDTV) to digital cinema projection systems. A new DMD pixel architecture, called "FTP", was designed and qualified by Texas Instruments DLPTMTM Group in 2003 to meet increased performance objectives for brightness and contrast ratio. Coordination between design, test and fabrication groups was required to balance pixel performance requirements and manufacturing capability. "Corner Lot" designed experiments (DOE) were used to verify "fabrication space" available for the pixel design. The corner lot technique allows confirmation of manufacturability projections early in the design/qualification cycle. Through careful design and analysis of the corner-lot DOE, a balance of critical dimension (cd) "budgets" is possible so that specification and process control limits can be established that meet both customer and factory requirements. The application of corner-lot DOE is illustrated in a case history of the DMD "FTP" pixel. The process for balancing test parameter requirements with multiple critical dimension budgets is shown. MEMS/MOEMS device design and fabrication can use similar techniques to achieve agressive design-to-qualification goals.

Manufacturability: from design to SPC limits through "corner-lot" characterization

NASA Astrophysics Data System (ADS)

Hogan, Timothy J.; Baker, James C.; Wesneski, Lisa; Black, Robert S.; Rothenbury, Dave

2005-01-01

Texas Instruments" Digital Micro-mirror Device, is used in a wide variety of optical display applications ranging from fixed and portable projectors to high-definition television (HDTV) to digital cinema projection systems. A new DMD pixel architecture, called "FTP", was designed and qualified by Texas Instruments DLPTMTM Group in 2003 to meet increased performance objectives for brightness and contrast ratio. Coordination between design, test and fabrication groups was required to balance pixel performance requirements and manufacturing capability. "Corner Lot" designed experiments (DOE) were used to verify "fabrication space" available for the pixel design. The corner lot technique allows confirmation of manufacturability projections early in the design/qualification cycle. Through careful design and analysis of the corner-lot DOE, a balance of critical dimension (cd) "budgets" is possible so that specification and process control limits can be established that meet both customer and factory requirements. The application of corner-lot DOE is illustrated in a case history of the DMD "FTP" pixel. The process for balancing test parameter requirements with multiple critical dimension budgets is shown. MEMS/MOEMS device design and fabrication can use similar techniques to achieve agressive design-to-qualification goals.

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

3. CONSTRUCTION DETAIL WEST PORTAL SHOWING CONCRETE LINING. NOTE DRILL ...

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

3. CONSTRUCTION DETAIL WEST PORTAL SHOWING CONCRETE LINING. NOTE DRILL HOLES IN GRANITE AT RIGHT EDGE. US GEOLOGICAL SURVEY BENCHMARK AT BOTTOM CORNER OF SIDEWALK - 4,621 FEET. SLOT IN FAR WALL FOR SEMAPHORE OF OBSOLETE CARBON MONOXIDE WARNING SYSTEM. - Wawona Tunnel, Wawona Road through Turtleback Dome, Yosemite Village, Mariposa County, CA

Design and Preparation of Supported Au Catalyst with Enhanced Catalytic Activities by Rationally Positioning Au Nanoparticles on Anatase.

PubMed

Wang, Liang; Wang, Hong; Rice, Andrew E; Zhang, Wei; Li, Xiaokun; Chen, Mingshu; Meng, Xiangju; Lewis, James P; Xiao, Feng-Shou

2015-06-18

A synergistic effect between individual components is crucial for increasing the activity of metal/metal oxide catalysts. The greatest challenge is how to control the synergistic effect to obtain enhanced catalytic performance. Through density functional theory calculations of model Au/TiO2 catalysts, it is suggested that there is strong interaction between Au nanoparticles and Ti species at the edge/corner sites of anatase, which is favorable for the formation of stable oxygen vacancies. Motivated by this theoretical analysis, we have rationally prepared Au nanoparticles attached to edge/corner sites of anatase support (Au/TiO2-EC), confirmed by their HR-TEM images. As expected, this strong interaction is well characterized by Raman, UV-visible, and XPS techniques. Very interestingly, compared with conventional Au catalysts, Au/TiO2-EC exhibits superior catalytic activity in the oxidations using O2. Our approach to controlling Au nanoparticle positioning on anatase to obtain enhanced catalytic activity offers an efficient strategy for developing more novel supported metal catalysts.

Optical properties of truncated Au nanocages with different size and shape

NASA Astrophysics Data System (ADS)

Chen, Qin; Qi, Hong; Ren, Ya-Tao; Sun, Jian-Ping; Ruan, Li-Ming

2017-06-01

The hollow nanostructures are conducive to applications including drug delivery, energy storage and conversion, and catalysis. In the present work, a versatile type of Au nanoparticles, i.e. nanocage with hollow interior, was studied thoroughly. Simulation of the optical properties of nanocages with different sizes and shapes was presented, which is essential for tuning the localized surface plasmon resonance peak. The edge length, side length of triangle, and wall thickness were used as structural parameters of truncated Au nanocage. The dependence of absorption efficiency, resonant wavelength, and absorption quantum yield on the structural parameters were discussed. Meanwhile, the applications of absorption quantum yield in biomedical imaging and laser induced thermal therapy were investigated. It was found that the phenomenon of multipolar plasmon resonances exists on truncated Au nanocage. Furthermore, the electric field distribution at different resonant wavelengths was also investigated. It is found that the electromagnetic field corresponds to the dipolar mode in an individual nanocage is largely distributed at the corners. Whereas, the electromagnetic field corresponds to the multipolar region is mainly located in the internal corners and edges.

FNS Research Corner: Summary of Research

ERIC Educational Resources Information Center

Gola, Alice Ann H.; Burdg, Jinee

2018-01-01

The FNS Research Corner provides a continuing series to summarize recently completed and current research conducted by the U.S. Department of Agriculture's Food and Nutrition Service (FNS) in the area of child nutrition. Summaries of recently completed research projects and in-progress research are provided in this article.

22. Detail of interior corner showing truss system, dock no. ...

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

22. Detail of interior corner showing truss system, dock no. 492. View to south. - Offutt Air Force Base, Looking Glass Airborne Command Post, Nose Docks, On either side of Hangar Access Apron at Northwest end of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

Enabler operator station. [lunar surface vehicle

NASA Technical Reports Server (NTRS)

Bailey, Andrea; Keitzman, John; King, Shirlyn; Stover, Rae; Wegner, Torsten

1992-01-01

The objective of this project was to design an onboard operator station for the conceptual Lunar Work Vehicle (LWV). This LWV would be used in the colonization of a lunar outpost. The details that follow, however, are for an earth-bound model. Several recommendations are made in the appendix as to the changes needed in material selection for the lunar environment. The operator station is designed dimensionally correct for an astronaut wearing the current space shuttle EVA suit (which includes life support). The proposed operator station will support and restrain an astronaut as well as provide protection from the hazards of vehicle rollover. The threat of suit puncture is eliminated by rounding all corners and edges. A step-plate, located at the front of the vehicle, provides excellent ease of entry and exit. The operator station weight requirements are met by making efficient use of grid members, semi-rigid members and woven fabrics.

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.

An Agile Framework for Real-Time Visual Tracking in Videos

DTIC Science & Technology

2012-09-05

multiplied by the structure tensor , for which there are two eigenvalues λ1 and λ2; if either or both is large and positive, an edge or corner is found...cannot learn to an accuracy better than 1/2. This holds even if the boosting algorithm stops early or the voting weights are bounded. Consider two sets

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...

View of crater Posidonius at edge of Sea of Serenity seen by Apollo 15

NASA Technical Reports Server (NTRS)

1971-01-01

An oblique view of a portion of the large crater Posidonius at the northeastern edge of the Sea of Serenity, as photographed from the Apollo 15 spacecraft in lunar orbit. Posidonius P is in the corner of the picture. The much smaller crater nearby is Posidonius F. The crater inside Posidonius is Posidonius A. Rima Posidonius II extends along inside Posidonius. The diamter of Posidonius is approximately 100 kilometers (about 62 statute miles). Posidonius is partly filled and the rim partly covered with mare material. This view is looking northwestward.

Multi-sensor image registration based on algebraic projective invariants.

PubMed

Li, Bin; Wang, Wei; Ye, Hao

2013-04-22

A new automatic feature-based registration algorithm is presented for multi-sensor images with projective deformation. Contours are firstly extracted from both reference and sensed images as basic features in the proposed method. Since it is difficult to design a projective-invariant descriptor from the contour information directly, a new feature named Five Sequential Corners (FSC) is constructed based on the corners detected from the extracted contours. By introducing algebraic projective invariants, we design a descriptor for each FSC that is ensured to be robust against projective deformation. Further, no gray scale related information is required in calculating the descriptor, thus it is also robust against the gray scale discrepancy between the multi-sensor image pairs. Experimental results utilizing real image pairs are presented to show the merits of the proposed registration method.

Directional control of lamellipodia extension by constraining cell shape and orienting cell tractional forces

NASA Technical Reports Server (NTRS)

Parker, Kevin Kit; Brock, Amy Lepre; Brangwynne, Cliff; Mannix, Robert J.; Wang, Ning; Ostuni, Emanuele; Geisse, Nicholas A.; Adams, Josephine C.; Whitesides, George M.; Ingber, Donald E.

2002-01-01

Directed cell migration is critical for tissue morphogenesis and wound healing, but the mechanism of directional control is poorly understood. Here we show that the direction in which cells extend their leading edge can be controlled by constraining cell shape using micrometer-sized extracellular matrix (ECM) islands. When cultured on square ECM islands in the presence of motility factors, cells preferentially extended lamellipodia, filopodia, and microspikes from their corners. Square cells reoriented their stress fibers and focal adhesions so that tractional forces were concentrated in these corner regions. When cell tension was dissipated, lamellipodia extension ceased. Mechanical interactions between cells and ECM that modulate cytoskeletal tension may therefore play a key role in the control of directional cell motility.

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.

Step Bunching: Influence of Impurities and Solution Flow

NASA Technical Reports Server (NTRS)

Chernov, A. A.; Vekilov, P. G.; Coriell, S. R.; Murray, B. T.; McFadden, G. B.

1999-01-01

Step bunching results in striations even at relatively early stages of its development and in inclusions of mother liquor at the later stages. Therefore, eliminating step bunching is crucial for high crystal perfection. At least 5 major effects causing and influencing step bunching are known: (1) Basic morphological instability of stepped interfaces. It is caused by concentration gradient in the solution normal to the face and by the redistribution of solute tangentially to the interface which redistribution enhances occasional perturbations in step density due to various types of noise; (2) Aggravation of the above basic instability by solution flowing tangentially to the face in the same directions as the steps or stabilization of equidistant step train if these flows are antiparallel; (3) Enhanced bunching at supersaturation where step velocity v increases with relative supersaturation s much faster than linear. This v(s) dependence is believed to be associated with impurities. The impurities of which adsorption time is comparable with the time needed to deposit one lattice layer may also be responsible for bunching; (4) Very intensive solution flow stabilizes growing interface even at parallel solution and step flows; (5) Macrosteps were observed to nucleate at crystal corners and edges. Numerical simulation, assuming step-step interactions via surface diffusion also show that step bunching may be induced by random step nucleation at the facet edge and by discontinuity in the step density (a ridge) somewhere in the middle of a face. The corresponding bunching patterns produce the ones observed in experiment. The nature of step bunching generated at the corners and edges and by dislocation step sources, as well as the also relative importance and interrelations between mechanisms 1-5 is not clear, both from experimental and theoretical standpoints. Furthermore, several laws controlling the evolution of existing step bunches have been suggested, though unambiguous conclusions are still missing. Addressing these issues is the major goal of the present project. The theory addressing the above problem, experimental methods, several figures which include: (1) the spatial wave numbers at which the system is neutrally stable as a function of growth velocity for linear kinetics and supersaturation for nonlinear kinetics; (2) a schematic of the experiment of lysozyme crystal growing under conditions of natural convection; (3) fluctuations in time, t, of the normal growth rate, R(t), vicinal slope, p(t) and Fourier Spectra of R(t), discussions and conclusions are presented.

Seamless stitching of tile scan microscope images.

PubMed

Legesse, F B; Chernavskaia, O; Heuke, S; Bocklitz, T; Meyer, T; Popp, J; Heintzmann, R

2015-06-01

For diagnostic purposes, optical imaging techniques need to obtain high-resolution images of extended biological specimens in reasonable time. The field of view of an objective lens, however, is often smaller than the sample size. To image the whole sample, laser scanning microscopes acquire tile scans that are stitched into larger mosaics. The appearance of such image mosaics is affected by visible edge artefacts that arise from various optical aberrations which manifest in grey level jumps across tile boundaries. In this contribution, a technique for stitching tiles into a seamless mosaic is presented. The stitching algorithm operates by equilibrating neighbouring edges and forcing the brightness at corners to a common value. The corrected image mosaics appear to be free from stitching artefacts and are, therefore, suited for further image analysis procedures. The contribution presents a novel method to seamlessly stitch tiles captured by a laser scanning microscope into a large mosaic. The motivation for the work is the failure of currently existing methods for stitching nonlinear, multimodal images captured by our microscopic setups. Our method eliminates the visible edge artefacts that appear between neighbouring tiles by taking into account the overall illumination differences among tiles in such mosaics. The algorithm first corrects the nonuniform brightness that exists within each of the tiles. It then compensates for grey level differences across tile boundaries by equilibrating neighbouring edges and forcing the brightness at the corners to a common value. After these artefacts have been removed further image analysis procedures can be applied on the microscopic images. Even though the solution presented here is tailored for the aforementioned specific case, it could be easily adapted to other contexts where image tiles are assembled into mosaics such as in astronomical or satellite photos. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

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.

Control of electromagnetic edge effects in electrically-small rectangular plasma reactors

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

Trampel, Christopher P.; Stieler, Daniel S.; PowerFilm, Inc., 2337 230th Street, Ames, Iowa 50014

Electromagnetic fields supported by rectangular reactors for plasma enhanced chemical vapor deposition are studied theoretically. Expressions for the fields in an electrically-small rectangular reactor with plasma in the chamber are derived. Modal field decompositions are employed under the homogeneous plasma slab approximation. The amplitude of each mode is determined analytically. It is shown that the field can be represented by the standing wave, evanescent waves tied to the edges, and an evanescent wave tied to the corners of the reactor. The impact of boundary conditions at the plasma edge on nonuniformity is quantified. Uniformity may be improved by placing amore » lossy magnetic layer on the reactor sidewalls. It is demonstrated that nonuniformity is a decreasing function of layer thickness.« less

78 FR 53467 - John H. Chafee Coastal Barrier Resources System; Delaware, North Carolina, South Carolina...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-29

... shorelines, stream channels, edges of marshes or wetlands, roads, and jetties. The CBRS boundaries must be..., intersections of roads, corners of large buildings, etc.) tested to be accurate to 1/50 of an inch on the map... shorelines, accreted sand spits, changes in the configuration of the wetlands, etc.) have occurred since 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...

New Failure Mode of Flip-Chip Solder Joints Related to the Metallization of an Organic Substrate

NASA Astrophysics Data System (ADS)

Jang, J. W.; Yoo, S. J.; Hwang, H. I.; Yuk, S. Y.; Kim, C. K.; Kim, S. J.; Han, J. S.; An, S. H.

2015-10-01

We report a new failure phenomenon during flip-chip die attach. After reflow, flip-chip bumps were separated between the Al and Ti layers on the Si die side. This was mainly observed at the Si die corner. Transmission electron microscopy images revealed corrosion of the Al layer at the edge of the solder bump metallization. The corrosion at the metallization edge exhibited a notch shape with high stress concentration factor. The organic substrate had Cu metallization with an organic solderable preservative (OSP) coating layer, where a small amount of Cl ions were detected. A solder bump separation mechanism is suggested based on the reaction between Al and Cl, related to the flow of soldering flux. During reflow, the flux will dissolve the Cl-containing OSP layer and flow up to the Al layer on the Si die side. Then, the Cl-dissolved flux will actively react with Al, forming AlCl3. During cooling, solder bumps at the Si die corner will separate through the location of Al corrosion. This demonstrated that the chemistry of the substrate metallization can affect the thermomechanical reliability of flip-chip solder joints.

Asymptotic modal analysis and statistical energy analysis

NASA Technical Reports Server (NTRS)

Dowell, Earl H.

1988-01-01

Statistical Energy Analysis (SEA) is defined by considering the asymptotic limit of Classical Modal Analysis, an approach called Asymptotic Modal Analysis (AMA). The general approach is described for both structural and acoustical systems. The theoretical foundation is presented for structural systems, and experimental verification is presented for a structural plate responding to a random force. Work accomplished subsequent to the grant initiation focusses on the acoustic response of an interior cavity (i.e., an aircraft or spacecraft fuselage) with a portion of the wall vibrating in a large number of structural modes. First results were presented at the ASME Winter Annual Meeting in December, 1987, and accepted for publication in the Journal of Vibration, Acoustics, Stress and Reliability in Design. It is shown that asymptotically as the number of acoustic modes excited becomes large, the pressure level in the cavity becomes uniform except at the cavity boundaries. However, the mean square pressure at the cavity corner, edge and wall is, respectively, 8, 4, and 2 times the value in the cavity interior. Also it is shown that when the portion of the wall which is vibrating is near a cavity corner or edge, the response is significantly higher.

Characterization of Fatigue Damage for Bonded Composite Skin/Stringer Configurations

NASA Technical Reports Server (NTRS)

Paris, Isabelle; Cvitkovich, Michael; Krueger, Ronald

2008-01-01

The fatigue damage was characterized in specimens which consisted of a tapered composite flange bonded onto a composite skin. Quasi-static tension tests were performed first to determine the failure load. Subsequently, tension fatigue tests were performed at 40%, 50%, 60% and 70% of the failure load to evaluate the debonding mechanisms. For four specimens, the cycling loading was stopped at intervals. Photographs of the polished specimen edges were taken under a light microscope to document the damage. At two diagonally opposite corners of the flange, a delamination appeared to initiate at the flange tip from a matrix crack in the top 45deg skin ply and propagated at the top 45deg/-45deg skin ply interface. At the other two diagonally opposite corners, a delamination running in the bondline initiated from a matrix crack in the adhesive pocket. In addition, two specimens were cut longitudinally into several sections. Micrographs revealed a more complex pattern inside the specimen where the two delamination patterns observed at the edges are present simultaneously across most of the width of the specimen. The observations suggest that a more sophisticated nondestructive evaluation technique is required to capture the complex damage pattern of matrix cracking and multi-level delaminations.

Comparison of test protocols for standard room/corner tests

Treesearch

R. H. White; M. A. Dietenberger; H. Tran; O. Grexa; L. Richardson; K. Sumathipala; M. Janssens

1998-01-01

As part of international efforts to evaluate alternative reaction-to-fire tests, several series of room/comer tests have been conducted. This paper reviews the overall results of related projects in which different test protocols for standard room/corner tests were used. Differences in the test protocols involved two options for the ignition burner scenario and whether...

Robot acting on moving bodies (RAMBO): Preliminary results

NASA Technical Reports Server (NTRS)

Davis, Larry S.; Dementhon, Daniel; Bestul, Thor; Ziavras, Sotirios; Srinivasan, H. V.; Siddalingaiah, Madju; Harwood, David

1989-01-01

A robot system called RAMBO is being developed. It is equipped with a camera, which, given a sequence of simple tasks, can perform these tasks on a moving object. RAMBO is given a complete geometric model of the object. A low level vision module extracts and groups characteristic features in images of the object. The positions of the object are determined in a sequence of images, and a motion estimate of the object is obtained. This motion estimate is used to plan trajectories of the robot tool to relative locations nearby the object sufficient for achieving the tasks. More specifically, low level vision uses parallel algorithms for image enchancement by symmetric nearest neighbor filtering, edge detection by local gradient operators, and corner extraction by sector filtering. The object pose estimation is a Hough transform method accumulating position hypotheses obtained by matching triples of image features (corners) to triples of model features. To maximize computing speed, the estimate of the position in space of a triple of features is obtained by decomposing its perspective view into a product of rotations and a scaled orthographic projection. This allows the use of 2-D lookup tables at each stage of the decomposition. The position hypotheses for each possible match of model feature triples and image feature triples are calculated in parallel. Trajectory planning combines heuristic and dynamic programming techniques. Then trajectories are created using parametric cubic splines between initial and goal trajectories. All the parallel algorithms run on a Connection Machine CM-2 with 16K processors.

National Program of Inspection of Non-Federal Dams, Tennessee. Glady Hollow Dam (OFDBA Site 41-1) (Inventory Number TN 13113), Obion River Basin, near Lassiter Corner, Tennessee, Obion County, Tennessee. Phase I Investigation Report.

DTIC Science & Technology

1981-09-01

collection pipes wrapped in filter cloth. The dam is situated near the edge of the loess bluffs in northwest Tennessee that overlooks Reelfoot Lake ...roughly six miles west of Hornbeak, in Obion County, Tennessee. The site is located near the edge of the loess bluff overlooking Reelfoot Lake to the...feet long with a crest width of 15 feet. It is in the small size and high hazard potential category. The structure impounds a 5.5 acre lake used for

Methodology for evaluating pattern transfer completeness in inkjet printing with irregular edges

NASA Astrophysics Data System (ADS)

Huang, Bo-Cin; Chan, Hui-Ju; Hong, Jian-Wei; Lo, Cheng-Yao

2016-06-01

A methodology for quantifying and qualifying pattern transfer completeness in inkjet printing through examining both pattern dimensions and pattern contour deviations from reference design is proposed, which enables scientifically identifying and evaluating inkjet-printed lines, corners, circles, ellipses, and spirals with irregular edges of bulging, necking, and unpredictable distortions resulting from different process conditions. This methodology not only avoids differences in individual perceptions of ambiguous pattern distortions but also indicates the systematic effects of mechanical stresses applied in different directions to a polymer substrate, and is effective for both optical and electrical microscopy in direct and indirect lithography or lithography-free patterning.

Earth Science

NASA Image and Video Library

2001-01-01

A NASA team studying the causes of electrical storms and their effects on our home planet achieved a milestone on August 21, 2002, completing the study's longest-duration research flight and monitoring four thunderstorms in succession. Radio news media can talk with Dr. Richard Blakeslee, the project's principal investigator, and Tony Kim, project manager at the Marshall Space Flight Center (MSFC), about their results and how their work will help improve future weather forecasting ability. Based at the Naval Air Station Key West, Florida, researchers with the Altus Cumulus Electrification Study (ACES) used the Altus II remotely- piloted aircraft to study a thunderstorm in the Atlantic Ocean off Key West, two storms at the western edge of the Everglades, and a large storm over the northwestern corner of the Everglades. This photograph shows Tony Kim And Dr. Richard Blakeslee of MSFC testing aircraft sensors that would be used to measure the electric fields produced by thunderstorm as part of NASA's ACES. With dual goals of gathering weather data safely and testing the adaptability of the uninhabited aircraft, the ACES study is a collaboration among the MSFC, the University of Alabama in Huntsville, NASA's Goddard Space Flight Center in Greenbelt, Maryland, Pernsylvania State University in University Park, and General Atomics Aeronautical Systems, Inc.

Acoustic Emission Measurements for Tool Wear Evaluation in Drilling

NASA Astrophysics Data System (ADS)

Gómez, Martín P.; Migliori, Julio; Ruzzante, José E.; D'Attellis, Carlos E.

2009-03-01

In this work, the tool condition in a drilling process of SAE 1040 steel samples was studied by means of acoustic emission. The studied drill bits were modified with artificial and real failures, such as different degrees of wear in the cutting edge and in the outer corner. Some correlation between mean power of the acoustic emission parameters and the drill bit wear condition was found.

Majorana states in prismatic core-shell nanowires

NASA Astrophysics Data System (ADS)

Manolescu, Andrei; Sitek, Anna; Osca, Javier; Serra, Llorenç; Gudmundsson, Vidar; Stanescu, Tudor Dan

2017-09-01

We consider core-shell nanowires with conductive shell and insulating core and with polygonal cross section. We investigate the implications of this geometry on Majorana states expected in the presence of proximity-induced superconductivity and an external magnetic field. A typical prismatic nanowire has a hexagonal profile, but square and triangular shapes can also be obtained. The low-energy states are localized at the corners of the cross section, i.e., along the prism edges, and are separated by a gap from higher energy states localized on the sides. The corner localization depends on the details of the shell geometry, i.e., thickness, diameter, and sharpness of the corners. We study systematically the low-energy spectrum of prismatic shells using numerical methods and derive the topological phase diagram as a function of magnetic field and chemical potential for triangular, square, and hexagonal geometries. A strong corner localization enhances the stability of Majorana modes to various perturbations, including the orbital effect of the magnetic field, whereas a weaker localization favorizes orbital effects and reduces the critical magnetic field. The prismatic geometry allows the Majorana zero-energy modes to be accompanied by low-energy states, which we call pseudo Majorana, and which converge to real Majoranas in the limit of small shell thickness. We include the Rashba spin-orbit coupling in a phenomenological manner, assuming a radial electric field across the shell.

Time for a Change; Spirit's View on Sol 1843 (Polar)

NASA Technical Reports Server (NTRS)

2009-01-01

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends.

This view is presented as a polar projection with geometric seam correction. North is at the top.

The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.'

The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

Time for a Change; Spirit's View on Sol 1843 (Vertical)

NASA Technical Reports Server (NTRS)

2009-01-01

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends.

This view is presented as a vertical projection with geometric seam correction. North is at the top.

The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.'

The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

View Ahead After Spirit's Sol 1861 Drive

NASA Technical Reports Server (NTRS)

2009-01-01

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this 210-degree view of the rover's surroundings during the 1,861st to 1,863rd Martian days, or sols, of Spirit's surface mission (March 28 to 30, 2009).

The center of the scene is toward the south-southwest. East is on the left. West-northwest is on the right.

The rover had driven 22.7 meters (74 feet) southwestward on Sol 1861 before beginning to take the frames in this view. The drive brought Spirit past the northwestern corner of Home Plate.

In this view, the western edge of Home Plate is on the portion of the horizon farthest to the left. A mound in middle distance near the center of the view is called 'Tsiolkovsky' and is about 40 meters (about 130 feet) from the rover's position.

This view is presented as a cylindrical projection with geometric seam correction.

Time for a Change; Spirit's View on Sol 1843

NASA Technical Reports Server (NTRS)

2009-01-01

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends.

The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.'

The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

This view is presented as a cylindrical projection with geometric seam correction.

Saturn's moon Rhea

NASA Technical Reports Server (NTRS)

1980-01-01

NASA's Voyager 1 took this high resolution color image of Rhea just before the spacecraft's closest approach to the Saturnian moon on Nov. 12, 1980 from a range of 128,000 kilometers (79,500 miles). The area shown is one of the most heavily cratered on Rhea, and indicates an ancient surface dating back to the period immediately following the formation of the planets 4.5 billion years ago. The photograph shows surface features about 2.5 kilometers (1.5 miles) in diameter, similar to a view of Earth's Moon through a telescope. Other areas of Rhea's surface are deficient in the very large (100 kilometers or 62 miles or larger) craters, indicating a change in the nature of the impacting bodies and an early period of surface activity. White areas on the edges of several of the craters in the upper right corner are probably fresh ice exposed on steep slopes or possibly deposited by volatiles leaking from fractured regions. The Voyager Project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California.

Modeling the Project Capacity of the Sacramento District Army Corps of Engineers

DTIC Science & Technology

2011-06-01

District. Added were all of Utah, except the southwest corner, Colorado from the Continental Divide west, the southwest corner of Wyoming, northeast corner...Sacramento 2011). 3 !. !. !. !. !. !. ^̀ Redding Reno St. George Bountiful Grand Junction Durango O r e g o n I d a h o W y o m i n gi C o l o r a d oU t a...114°W 114°W 123°W 123°W 42°N 42°N 34°N 34°N Legend Colorado West BranchCalifornia North Branch California Delta Branch ^̀ District Office District

Facile synthesis of silver nanocubes with sharp corners and edges in an aqueous solution

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

Zhou, Shan; Li, Jianhua; Gilroy, Kyle D.

It remains a challenge to synthesize Ag nanocubes in an aqueous system, although the polyol process was successfully adopted more than one decade ago. Here, we report an aqueous method for the synthesis of Ag nanocubes with an average edge length of 35–95 nm. It involves the formation of AgCl octahedra by mixing CF 3COOAg with cetyltrimethylammonium chloride, followed by the nucleation and growth of Ag nanocrystals in the presence of ascorbic acid (AA) and FeCl 3. The Fe 3+/Fe 2+ redox pair is responsible for the removal of multiply twinned seeds through oxidative etching. Here, the Cl – ionsmore » play two critical roles in the nucleation and growth of Ag nanocubes with a single-crystal structure. First, the Cl – ions react with Ag + ions to generate nanometer-sized AgCl octahedra in the initial stage of a synthesis. In the presence of room light and a proper reducing agent such as AA, the AgCl can be reduced to generate Ag n nuclei followed by their evolution into single-crystal seeds and then Ag nanocrystals. Second, the Cl – ions can act as a specific capping agent toward the Ag(100) surface, enabling the formation of Ag nanocubes with sharp corners and edges. Based on the results from a set of time-lapse studies and control experiments, we formulate a plausible mechanism to account for the formation of Ag nanocubes that resembles the formation and development of latent image centers in silver halide grains in the photographic process.« less

Facile synthesis of silver nanocubes with sharp corners and edges in an aqueous solution

DOE PAGES

Zhou, Shan; Li, Jianhua; Gilroy, Kyle D.; ...

2016-09-20

It remains a challenge to synthesize Ag nanocubes in an aqueous system, although the polyol process was successfully adopted more than one decade ago. Here, we report an aqueous method for the synthesis of Ag nanocubes with an average edge length of 35–95 nm. It involves the formation of AgCl octahedra by mixing CF 3COOAg with cetyltrimethylammonium chloride, followed by the nucleation and growth of Ag nanocrystals in the presence of ascorbic acid (AA) and FeCl 3. The Fe 3+/Fe 2+ redox pair is responsible for the removal of multiply twinned seeds through oxidative etching. Here, the Cl – ionsmore » play two critical roles in the nucleation and growth of Ag nanocubes with a single-crystal structure. First, the Cl – ions react with Ag + ions to generate nanometer-sized AgCl octahedra in the initial stage of a synthesis. In the presence of room light and a proper reducing agent such as AA, the AgCl can be reduced to generate Ag n nuclei followed by their evolution into single-crystal seeds and then Ag nanocrystals. Second, the Cl – ions can act as a specific capping agent toward the Ag(100) surface, enabling the formation of Ag nanocubes with sharp corners and edges. Based on the results from a set of time-lapse studies and control experiments, we formulate a plausible mechanism to account for the formation of Ag nanocubes that resembles the formation and development of latent image centers in silver halide grains in the photographic process.« less

Master-slave mixed arrays for data-flow computations

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

Chang, T.L.; Fisher, P.D.

1983-01-01

Control cells (masters) and computation cells (slaves) are mixed in regular geometric patterns to form reconfigurable arrays known as master-slave mixed arrays (MSMAS). Interconnections of the corners and edges of the hexagonal control cells and the edges of the hexagonal computation cells are used to construct synchronous and asynchronous communication networks, which support local computation and local communication. Data-driven computations result in self-directed ring pipelines within the MSMA, and composite data-flow computations are executed in a pipelined fashion. By viewing an MSMA as a computing network of tightly-linked ring pipelines, data-flow programs can be uniformly distributed over these pipelines formore » efficient resource utilisation. 9 references.« less

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

Sanjeewa, Liurukara D.; McMillen, Colin D.; McGuire, Michael A.

We synthesized manganese vanadate fluorides using high-temperature hydrothermal techniques with BaF 2 as a mineralizer. Ba 3Mn 2(V 2O 7) 2F 2 crystallizes in space group C2/c and consists of dimers built from edge-sharing MnO 4F 2 trigonal prisms with linking V 2O 7 groups. Ba 7Mn 8O 2(VO 4) 2F 23 crystallizes in space group Cmmm, with a manganese oxyfluoride network built from edge- and corner-sharing Mn 2+/3+(O,F) 6 octahedra. The resulting octahedra form alternating Mn 2+ and Mn 2+/3+ layers separated by VO 4 tetrahedra. This latter compound exhibits a canted antiferromagnetic order below TN = 25 K.

Far from City Lights: Current TCJ Staff Brings Variety of Talents, Enthusiasm for Their Work

ERIC Educational Resources Information Center

Talahongva, Patty

2009-01-01

Far from the glitzy streets of New York or Los Angeles... where many of this nation's magazines are published... and on the edge of the famed Four Corners Region in the town of Mancos, Colorado ...is the home of the Tribal College Journal (TCJ). Tucked away in the Rocky Mountains, it's much like the tribal colleges it serves, far from big city…

Oxygen reduction reaction activity and structural stability of Pt-Au nanoparticles prepared by arc-plasma deposition.

PubMed

Takahashi, Shuntaro; Chiba, Hiroshi; Kato, Takashi; Endo, Shota; Hayashi, Takehiro; Todoroki, Naoto; Wadayama, Toshimasa

2015-07-28

The oxygen reduction reaction (ORR) activity and durability of various Au(x)/Pt100 nanoparticles (where x is the atomic ratio of Au against Pt) are evaluated herein. The samples were fabricated on a highly-oriented pyrolytic graphite substrate at 773 K through sequential arc-plasma depositions of Pt and Au. The electrochemical hydrogen adsorption charges (electrochemical surface area), particularly the characteristic currents caused by the corner and edge sites of the Pt nanoparticles, decrease with increasing Au atomic ratio (x). In contrast, the specific ORR activities of the Au(x)/Pt100 samples were dependent on the atomic ratios of Pt and Au: the Au28/Pt100 sample showed the highest specific activity among all the investigated samples (x = 0-42). As for ORR durability evaluated by applying potential cycles between 0.6 and 1.0 V in oxygen-saturated 0.1 M HClO4, Au28/Pt100 was the most durable sample against the electrochemical potential cycles. The results clearly showed that the Au atoms located at coordinatively-unsaturated sites, e.g. at the corners or edges of the Pt nanoparticles, can improve the ORR durability by suppressing unsaturated-site-induced degradation of the Pt nanoparticles.

Mechanism of mechanically induced optoelectronic and spintronic phase transitions in 1D graphene spirals: insight into the role of interlayer coupling.

PubMed

Xu, Xiaodong; Liu, Bingyi; Zhao, Wenyu; Jiang, Yongyuan; Liu, Linhua; Li, Weiqi; Zhang, Guiling; Tian, Wei Quan

2017-07-13

Graphene spirals (GSs), an emerging carbonic nano-material with a Riemann surface, demonstrate extraordinary topological electronic signatures: interlayer coupling similar to van der Waals (vdW) heterojunctions and intralayer coupling within the spiral conformation. Based on the state-of-the-art first-principles technique, the electronic properties of the periphery-modified GSs with geometry deformation are explored under axial strain. For all GSs, there emerges a remarkable phase transition from metal to semiconductor, due to the attenuation of interlayer "σ-bonds" reducing the interlayer tunneling probability for carriers. Analogous to graphene, GSs consist of bipartite sublattices with carbonic sp 2 hybridization as well. Once the balance of the bipartite sublattices is lost, there will emerge intense edge (corner) states, contributed by the p z orbitals. In contrast to isolated graphene nanoflakes, GSs realize the continuous spin-polarized edge (corner) state coupling with 1D morphology. However, the spin-polarization is blocked by the robust interlayer "σ-bonds" so that the spintronic transition takes place until this interlayer coupling is broken. More intriguingly, an indirect-direct bandgap transition is observed, revealing excellent optical on-off features. Their tunable properties provide great potential for their application in optoelectronics, spintronics and chemical or biological sensors.

Endohedral gallide cluster superconductors and superconductivity in ReGa5.

PubMed

Xie, Weiwei; Luo, Huixia; Phelan, Brendan F; Klimczuk, Tomasz; Cevallos, Francois Alexandre; Cava, Robert Joseph

2015-12-22

We present transition metal-embedded (T@Gan) endohedral Ga-clusters as a favorable structural motif for superconductivity and develop empirical, molecule-based, electron counting rules that govern the hierarchical architectures that the clusters assume in binary phases. Among the binary T@Gan endohedral cluster systems, Mo8Ga41, Mo6Ga31, Rh2Ga9, and Ir2Ga9 are all previously known superconductors. The well-known exotic superconductor PuCoGa5 and related phases are also members of this endohedral gallide cluster family. We show that electron-deficient compounds like Mo8Ga41 prefer architectures with vertex-sharing gallium clusters, whereas electron-rich compounds, like PdGa5, prefer edge-sharing cluster architectures. The superconducting transition temperatures are highest for the electron-poor, corner-sharing architectures. Based on this analysis, the previously unknown endohedral cluster compound ReGa5 is postulated to exist at an intermediate electron count and a mix of corner sharing and edge sharing cluster architectures. The empirical prediction is shown to be correct and leads to the discovery of superconductivity in ReGa5. The Fermi levels for endohedral gallide cluster compounds are located in deep pseudogaps in the electronic densities of states, an important factor in determining their chemical stability, while at the same time limiting their superconducting transition temperatures.

Description of the Posterolateral Rotatory Drawer Maneuver for the Identification of Posterolateral Corner Injury

PubMed Central

Angelini, Fábio Janson; Bonadio, Marcelo Batista; Helito, Camilo Partezani; da Mota e Albuquerque, Roberto Freire; Pécora, José Ricardo; Camanho, Gilberto Luis

2014-01-01

Injury to the posterolateral corner (PLC) is difficult to diagnose; most lesions of this type are included within the context of complex knee injuries. Study of the posterolateral complex is growing in importance because of the complex instability generated by these injuries. Although various physical examination tests are described for the diagnosis of PLC lesions, in 72% of cases these lesions are not identified at their initial presentation, which shows the difficulty in both performing these tests and interpreting the results. The maneuver described in this report is performed by executing external rotation of the leg. With the thumb of the proximally positioned hand, the examiner evaluates the positioning of the lateral tibial plateau in relation to the femoral condyle. With this maneuver, in lesions of the PLC and particularly lesions of its external rotation–restricting structures, we observe external rotation of the tibia and posterior subluxation of the lateral tibial plateau that cause the anterior edge of the tibial plateau to be posteriorized in relation to the anterior edge of the lateral femoral condyle. The idea behind this maneuver is not to eliminate the use of other tests but, rather, to add it to a diagnostic arsenal that still has interpretation flaws. PMID:24904781

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.

Effects of Wing Leading Edge Penetration with Venting and Exhaust Flow from Wheel Well at Mach 24 in Flight

NASA Technical Reports Server (NTRS)

Gnoffo, Peter A.

2003-01-01

A baseline solution for CFD Point 1 (Mach 24) in the STS-107 accident investigation was modified to include effects of: (1) holes through the leading edge into a vented cavity; and (2) a scarfed, conical nozzle directed toward the centerline of the vehicle from the forward, inboard corner of the landing gear door. The simulations were generated relatively quickly and early in the investigation because simplifications were made to the leading edge cavity geometry and an existing utility to merge scarfed nozzle grid domains with structured baseline external domains was implemented. These simplifications in the breach simulations enabled: (1) a very quick grid generation procedure; and (2) high fidelity corroboration of jet physics with internal surface impingements ensuing from a breach through the leading edge, fully coupled to the external shock layer flow at flight conditions. These simulations provided early evidence that the flow through a two-inch diameter (or larger) breach enters the cavity with significant retention of external flow directionality. A normal jet directed into the cavity was not an appropriate model for these conditions at CFD Point 1 (Mach 24). The breach diameters were of the same order or larger than the local, external boundary-layer thickness. High impingement heating and pressures on the downstream lip of the breach were computed. It is likely that hole shape would evolve as a slot cut in the direction of the external streamlines. In the case of the six-inch diameter breach the boundary layer is fully ingested. The intent of externally directed jet simulations in the second scenario was to approximately model aerodynamic effects of a relatively large internal wing pressure, fueled by combusting aluminum, which deforms the corner of the landing gear door and directs a jet across the windside surface. These jet interactions, in and of themselves, were not sufficiently large to explain observed aerodynamic behavior.

Tungsten Carbide Grain Size Computation for WC-Co Dissimilar Welds

NASA Astrophysics Data System (ADS)

Zhou, Dongran; Cui, Haichao; Xu, Peiquan; Lu, Fenggui

2016-06-01

A "two-step" image processing method based on electron backscatter diffraction in scanning electron microscopy was used to compute the tungsten carbide (WC) grain size distribution for tungsten inert gas (TIG) welds and laser welds. Twenty-four images were collected on randomly set fields per sample located at the top, middle, and bottom of a cross-sectional micrograph. Each field contained 500 to 1500 WC grains. The images were recognized through clustering-based image segmentation and WC grain growth recognition. According to the WC grain size computation and experiments, a simple WC-WC interaction model was developed to explain the WC dissolution, grain growth, and aggregation in welded joints. The WC-WC interaction and blunt corners were characterized using scanning and transmission electron microscopy. The WC grain size distribution and the effects of heat input E on grain size distribution for the laser samples were discussed. The results indicate that (1) the grain size distribution follows a Gaussian distribution. Grain sizes at the top of the weld were larger than those near the middle and weld root because of power attenuation. (2) Significant WC grain growth occurred during welding as observed in the as-welded micrographs. The average grain size was 11.47 μm in the TIG samples, which was much larger than that in base metal 1 (BM1 2.13 μm). The grain size distribution curves for the TIG samples revealed a broad particle size distribution without fine grains. The average grain size (1.59 μm) in laser samples was larger than that in base metal 2 (BM2 1.01 μm). (3) WC-WC interaction exhibited complex plane, edge, and blunt corner characteristics during grain growth. A WC ( { 1 {bar{{1}}}00} ) to WC ( {0 1 1 {bar{{0}}}} ) edge disappeared and became a blunt plane WC ( { 10 1 {bar{{0}}}} ) , several grains with two- or three-sided planes and edges disappeared into a multi-edge, and a WC-WC merged.

Science Explorers Translation Project.

ERIC Educational Resources Information Center

Jacobs, Dolores

This paper describes a pilot project of Los Alamos National Laboratory (New Mexico) to translate a science education curriculum for junior and senior high school students into Navajo. The project consisted of translating a video, a teacher's guide, and an interactive multimedia product on the 1993 hantavirus outbreak in the Four Corners area…

Advanced Concepts for Composite Structure Joints and Attachment Fittings. Volume I. Design and Evaluation.

DTIC Science & Technology

1981-11-01

interlaminar tension). The analysis is also influenced by other factors such as bolt location, washer/bolt size, fastener pattern, laminate thickness, corner...to reduce the cost of tooling were also studied. These include: * Pultrusion dies for under $5, 000 * Stable, accurate, low-cost chopped-fiber phenolic ...fittings were state-of- the-art methods developed for laminated composite plates, shells, beams, and columns as used in analyses of discontinuities, edge

An Experimental and Analytical Study of TIP Clearance Effects in Axial Flow Compressors

DTIC Science & Technology

1991-12-01

increasingly being used for design insight into the flow field. Implementations of the Navier Stokes equations using interacting grids or similar schemes...analytical reason for the existence of a pressure minimum locus lving away from the suction corner is provided by Barclay (1982) in a solution for the...relief at the leading edge on the suction side, grid Sensitivity and similar computational concerns, the computations predict %khat the blade loading

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.

Midwestern United States as seen from STS-58

NASA Image and Video Library

1993-10-30

STS058-102-018 (18 Oct-1 Nov 1993) --- A cloud-free, wide-angle view from above western Tennessee to the northern edge of Lake Michigan. The view extends from Saint Louis, Missouri near the lower left-hand corner, past Evansville, Indiana and Louisville, Kentucky to Cincinnati, Ohio. A range of hills covered by trees in Fall foliage extends from the Ohio River toward Lake Michigan, ending just southwest of Indianapolis, Indiana.

UTD analysis of electromagnetic scattering by flat structures. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Sikta, F. A.; Peters, L., Jr.

1981-01-01

The different scattering mechanisms that contribute to the radar cross of finite flat plates were identified and analyzed. The geometrical theory of diffraction, the equivalent current and the corner diffraction are used for this study. A study of the cross polarized field for a monopole mounted on a plate is presented, using novel edge wave mechanism in the analysis. The results are compared with moment method solutions as well as measured data.

MTR BUILDING, TRA603. SOUTHEAST CORNER, EAST SIDE FACING TOWARD RIGHT ...

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

MTR BUILDING, TRA-603. SOUTHEAST CORNER, EAST SIDE FACING TOWARD RIGHT OF VIEW. CAMERA FACING NORTHWEST. LIGHT-COLORED PROJECTION AT LEFT IS ENGINEERING SERVICES BUILDING, TRA-635. SMALL CONCRETE BLOCK BUILDING AT CENTER OF VIEW IS FAST CHOPPER DETECTOR HOUSE, TRA-665. INL NEGATIVE NO. HD46-43-3. Mike Crane, Photographer, 4/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

All-quad meshing without cleanup

DOE PAGES

Rushdi, Ahmad A.; Mitchell, Scott A.; Mahmoud, Ahmed H.; ...

2016-08-22

Here, we present an all-quad meshing algorithm for general domains. We start with a strongly balanced quadtree. In contrast to snapping the quadtree corners onto the geometric domain boundaries, we move them away from the geometry. Then we intersect the moved grid with the geometry. The resulting polygons are converted into quads with midpoint subdivision. Moving away avoids creating any flat angles, either at a quadtree corner or at a geometry–quadtree intersection. We are able to handle two-sided domains, and more complex topologies than prior methods. The algorithm is provably correct and robust in practice. It is cleanup-free, meaning wemore » have angle and edge length bounds without the use of any pillowing, swapping, or smoothing. Thus, our simple algorithm is fast and predictable. This paper has better quality bounds, and the algorithm is demonstrated over more complex domains, than our prior version.« less

All-quad meshing without cleanup

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

Rushdi, Ahmad A.; Mitchell, Scott A.; Mahmoud, Ahmed H.

Here, we present an all-quad meshing algorithm for general domains. We start with a strongly balanced quadtree. In contrast to snapping the quadtree corners onto the geometric domain boundaries, we move them away from the geometry. Then we intersect the moved grid with the geometry. The resulting polygons are converted into quads with midpoint subdivision. Moving away avoids creating any flat angles, either at a quadtree corner or at a geometry–quadtree intersection. We are able to handle two-sided domains, and more complex topologies than prior methods. The algorithm is provably correct and robust in practice. It is cleanup-free, meaning wemore » have angle and edge length bounds without the use of any pillowing, swapping, or smoothing. Thus, our simple algorithm is fast and predictable. This paper has better quality bounds, and the algorithm is demonstrated over more complex domains, than our prior version.« less

Analysis and numerical simulation research of the heating process in the oven

NASA Astrophysics Data System (ADS)

Chen, Yawei; Lei, Dingyou

2016-10-01

How to use the oven to bake delicious food is the most concerned problem of the designers and users of the oven. For this intent, this paper analyzed the heat distribution in the oven based on the basic operation principles and proceeded the data simulation of the temperature distribution on the rack section. Constructing the differential equation model of the temperature distribution changes in the pan when the oven works based on the heat radiation and heat transmission, based on the idea of utilizing cellular automation to simulate heat transfer process, used ANSYS software to proceed the numerical simulation analysis to the rectangular, round-cornered rectangular, elliptical and circular pans and giving out the instantaneous temperature distribution of the corresponding shapes of the pans. The temperature distribution of the rectangular and circular pans proves that the product gets overcooked easily at the corners and edges of rectangular pans but not of a round pan.

Apollo 9 Mission image - S0-65 Multispectral Photography - Alabama

NASA Image and Video Library

2009-02-19

AS09-26A-3790A (11 March 1969) --- Color infrared photograph of the Birmingham to Gadsden area of Alabama as seen from the Apollo 9 spacecraft during its 121st revolution of Earth. This picture was taken as a part of the SO65 Multispectral Terrain Photography Experiment. Birmingham is at left center edge of picture; Gadsden is near top center edge of photograph. Note folded mountains of southern Appalachian chain extending northeast-southwest. The major river in picture which runs generally southward is the Coosa River. The Tallapoosa River, which flows into Lake Martin, is in the southeast corner of picture. Interstate 20 runs from Birmingham eastward toward Atlanta. The City of Anniston is south of Gadsden on Interstate 20.

The Influence of Clocking Angle of the Projectile on the Simulated Impact Response of a Shuttle Leading Edge Wing Panel

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fasanella, Edwin L.; Lyle, Karen H.; Spellman, Regina L.

2005-01-01

An analytical study was conducted to determine the influence of clocking angle of a foam projectile impacting a space shuttle leading edge wing panel. Four simulations were performed using LS-DYNA. The leading edge panels are fabricated of multiple layers of reinforced carbon-carbon (RCC) material. The RCC material was represented using Mat 58, which is a material property that can be used for laminated composite fabrics. Simulations were performed of a rectangular-shaped foam block, weighing 0.23-lb., impacting RCC Panel 9 on the top surface. The material properties of the foam were input using Mat 83. The impact velocity was 1,000 ft/s along the Orbiter X-axis. In two models, the foam impacted on a corner, in one model the foam impacted the panel initially on the 2-in.-long edge, and in the last model the foam impacted the panel on the 7-in.- long edge. The simulation results are presented as contour plots of first principal infinitesimal strain and time history plots of contact force and internal and kinetic energy of the foam and RCC panel.

Volcanic signature of Basin and Range extension on the shrinking Cascade arc, Klamath Falls-Keno area, Oregon

NASA Astrophysics Data System (ADS)

Priest, George R.; Hladky, Frank R.; Mertzman, Stanley A.; Murray, Robert B.; Wiley, Thomas J.

2013-08-01

geologic mapping of the Klamath Falls-Keno area revealed the complex relationship between subduction, crustal extension, and magmatic composition of the southern Oregon Cascade volcanic arc. Volcanism in the study area at 7-4 Ma consisted of calc-alkaline basaltic andesite and andesite lava flowing over a relatively flat landscape. Local angular unconformities are evidence that Basin and Range extension began at by at least 4 Ma and continues today with fault blocks tilting at a long-term rate of 2°/Ma to 3°/Ma. Minimum NW-SE extension is 1.5 km over 28 km ( 5%). High-alumina olivine tholeiite (HAOT) or low-K, low-Ti transitional high-alumina olivine tholeiite (LKLT) erupted within and adjacent to the back edge of the calc-alkaline arc as the edge receded westward at a rate of 10 km/Ma at 2.7-0.45 Ma. The volcanic front migrated east much slower than the back arc migrated west: 0 km/Ma for 6-0.4 Ma calc-alkaline rocks; 0.7 km/Ma, if 6 Ma HAOT-LKLT is included; and 1 km/Ma, if highly differentiated 17-30 Ma volcanic rocks of the early Western Cascades are included. Declining convergence probably decreased asthenospheric corner flow, decreasing width of calc-alkaline and HAOT-LKLT volcanism and the associated heat flow anomaly, the margins of which focused on Basin and Range extension and leakage of HAOT-LKLT magma to the surface. This declining corner flow combined with steepening slab dip shifted the back arc west. Compensation of extension by volcanic intrusion and extrusion allowed growth of imposing range-front fault scarps only behind the trailing edge of the shrinking arc.

Photonic topological boundary pumping as a probe of 4D quantum Hall physics

NASA Astrophysics Data System (ADS)

Zilberberg, Oded; Huang, Sheng; Guglielmon, Jonathan; Wang, Mohan; Chen, Kevin P.; Kraus, Yaacov E.; Rechtsman, Mikael C.

2018-01-01

When a two-dimensional (2D) electron gas is placed in a perpendicular magnetic field, its in-plane transverse conductance becomes quantized; this is known as the quantum Hall effect. It arises from the non-trivial topology of the electronic band structure of the system, where an integer topological invariant (the first Chern number) leads to quantized Hall conductance. It has been shown theoretically that the quantum Hall effect can be generalized to four spatial dimensions, but so far this has not been realized experimentally because experimental systems are limited to three spatial dimensions. Here we use tunable 2D arrays of photonic waveguides to realize a dynamically generated four-dimensional (4D) quantum Hall system experimentally. The inter-waveguide separation in the array is constructed in such a way that the propagation of light through the device samples over momenta in two additional synthetic dimensions, thus realizing a 2D topological pump. As a result, the band structure has 4D topological invariants (known as second Chern numbers) that support a quantized bulk Hall response with 4D symmetry. In a finite-sized system, the 4D topological bulk response is carried by localized edge modes that cross the sample when the synthetic momenta are modulated. We observe this crossing directly through photon pumping of our system from edge to edge and corner to corner. These crossings are equivalent to charge pumping across a 4D system from one three-dimensional hypersurface to the spatially opposite one and from one 2D hyperedge to another. Our results provide a platform for the study of higher-dimensional topological physics.

Photonic topological boundary pumping as a probe of 4D quantum Hall physics.

PubMed

Zilberberg, Oded; Huang, Sheng; Guglielmon, Jonathan; Wang, Mohan; Chen, Kevin P; Kraus, Yaacov E; Rechtsman, Mikael C

2018-01-03

When a two-dimensional (2D) electron gas is placed in a perpendicular magnetic field, its in-plane transverse conductance becomes quantized; this is known as the quantum Hall effect. It arises from the non-trivial topology of the electronic band structure of the system, where an integer topological invariant (the first Chern number) leads to quantized Hall conductance. It has been shown theoretically that the quantum Hall effect can be generalized to four spatial dimensions, but so far this has not been realized experimentally because experimental systems are limited to three spatial dimensions. Here we use tunable 2D arrays of photonic waveguides to realize a dynamically generated four-dimensional (4D) quantum Hall system experimentally. The inter-waveguide separation in the array is constructed in such a way that the propagation of light through the device samples over momenta in two additional synthetic dimensions, thus realizing a 2D topological pump. As a result, the band structure has 4D topological invariants (known as second Chern numbers) that support a quantized bulk Hall response with 4D symmetry. In a finite-sized system, the 4D topological bulk response is carried by localized edge modes that cross the sample when the synthetic momenta are modulated. We observe this crossing directly through photon pumping of our system from edge to edge and corner to corner. These crossings are equivalent to charge pumping across a 4D system from one three-dimensional hypersurface to the spatially opposite one and from one 2D hyperedge to another. Our results provide a platform for the study of higher-dimensional topological physics.

NASA Studies Lightning Storms Using High-Flying, Uninhabited Vehicle

NASA Technical Reports Server (NTRS)

2001-01-01

A NASA team studying the causes of electrical storms and their effects on our home planet achieved a milestone on August 21, 2002, completing the study's longest-duration research flight and monitoring four thunderstorms in succession. Radio news media can talk with Dr. Richard Blakeslee, the project's principal investigator, and Tony Kim, project manager at the Marshall Space Flight Center (MSFC), about their results and how their work will help improve future weather forecasting ability. Based at the Naval Air Station Key West, Florida, researchers with the Altus Cumulus Electrification Study (ACES) used the Altus II remotely- piloted aircraft to study a thunderstorm in the Atlantic Ocean off Key West, two storms at the western edge of the Everglades, and a large storm over the northwestern corner of the Everglades. This photograph shows Tony Kim And Dr. Richard Blakeslee of MSFC testing aircraft sensors that would be used to measure the electric fields produced by thunderstorm as part of NASA's ACES. With dual goals of gathering weather data safely and testing the adaptability of the uninhabited aircraft, the ACES study is a collaboration among the MSFC, the University of Alabama in Huntsville, NASA's Goddard Space Flight Center in Greenbelt, Maryland, Pernsylvania State University in University Park, and General Atomics Aeronautical Systems, Inc.

Design study of the geometry of the blanking tool to predict the burr formation of Zircaloy-4 sheet

NASA Astrophysics Data System (ADS)

Ha, Jisun; Lee, Hyungyil; Kim, Dongchul; Kim, Naksoo

2013-12-01

In this work, we investigated factors that influence burr formation for zircaloy-4 sheet used for spacer grids of nuclear fuel roads. Factors we considered are geometric factors of punch. We changed clearance and velocity in order to consider the failure parameters, and we changed shearing angle and corner radius of L-shaped punch in order to consider geometric factors of punch. First, we carried out blanking test with failure parameter of GTN model using L-shaped punch. The tendency of failure parameters and geometric factors that affect burr formation by analyzing sheared edges is investigated. Consequently, geometric factor's influencing on the burr formation is also high as failure parameters. Then, the sheared edges and burr formation with failure parameters and geometric factors is investigated using FE analysis model. As a result of analyzing sheared edges with the variables, we checked geometric factors more affect burr formation than failure parameters. To check the reliability of the FE model, the blanking force and the sheared edges obtained from experiments are compared with the computations considering heat transfer.

Reaction-to-Fire of Wood Products and Other Building Materials: Part 1, Room/Corner Test Performance

Treesearch

Ondrej Grexa; Mark A. Dietenberger; Robert H. White

2012-01-01

This project researched the assessment of reaction-to-fire of common materials using the full-scale room/corner test (ISO 9705) protocol and the predictions of time to flashover using results from the bench-scale cone calorimeter test (ISO 5660-1). Using a burner protocol of 100 kW for 10 min, followed by 300 kW for 10 min and the test materials on the walls only, we...

Visualization of defect-induced excitonic properties of the edges and grain boundaries in synthesized monolayer molybdenum disulfide

NASA Astrophysics Data System (ADS)

Newaz, Akm; Yore, A. E.; Miller, A.; Crumrine, W.; Redd, B.; Tuck, J. A.; Wang, Bin; Smithe, K. K. H.; Pop, E.

Understanding nanoscale optical behavior of the edges and grain boundaries of synthetically grown transition metal dichalcogenides (TMDCs) is vital for optimizing their optoelectronic properties. Here we present our experimental work on spatial photoluminescence (PL) scanning of large size (>= 50 μ m) monolayer MoS2 grown by chemical vapor deposition (CVD) using a diffraction limited blue laser beam spot (wavelength 405 nm) with a beam diameter as small as 200 nm allowing us to probe nanoscale excitonic phenomena which was not observed before. We have found several important features: (i) there exists a sub-micron width strip ( 500 nm) along the edges that fluoresces 1000 % brighter than the region far inside; (ii) there is another brighter wide region consisting of parallel fluorescing lines ending at the corners of the zig-zag peripheral edges; (iii) there is a giant blue shifted A-excitonic peak, as large as 120 meV, in the PL spectra from the edges. Using density functional theory calculations, we attribute this giant blue shift to the adsorption of oxygen dimers at the edges, which reduces the excitonic binding energy. Our results offer an attractive route to tailor optical properties at the TMDC edges through defect engineering. AFOSR Grant FA9550-14-1-0251, NSF EFRI 2-DARE Grant 1542883, NSF Graduate Research Fellowship under Grant DGE-114747.

Vortex Dynamics around Pitching Plates

DTIC Science & Technology

2014-04-29

electrical signals are A/D converted in an ATI NetBox interface and recorded using a Java application, and are filtered in three steps. The first is a low...the plate while staying attached to the corners of the leading edge. During this process, a second vortex loop, created by the quick angular ...is a spike in CL centered around t = 0 due to non-circulatory6 effects from the angular acceleration of the wing. The amplitude of the peak is

Endohedral gallide cluster superconductors and superconductivity in ReGa5

PubMed Central

Xie, Weiwei; Luo, Huixia; Phelan, Brendan F.; Klimczuk, Tomasz; Cevallos, Francois Alexandre; Cava, Robert Joseph

2015-01-01

We present transition metal-embedded (T@Gan) endohedral Ga-clusters as a favorable structural motif for superconductivity and develop empirical, molecule-based, electron counting rules that govern the hierarchical architectures that the clusters assume in binary phases. Among the binary T@Gan endohedral cluster systems, Mo8Ga41, Mo6Ga31, Rh2Ga9, and Ir2Ga9 are all previously known superconductors. The well-known exotic superconductor PuCoGa5 and related phases are also members of this endohedral gallide cluster family. We show that electron-deficient compounds like Mo8Ga41 prefer architectures with vertex-sharing gallium clusters, whereas electron-rich compounds, like PdGa5, prefer edge-sharing cluster architectures. The superconducting transition temperatures are highest for the electron-poor, corner-sharing architectures. Based on this analysis, the previously unknown endohedral cluster compound ReGa5 is postulated to exist at an intermediate electron count and a mix of corner sharing and edge sharing cluster architectures. The empirical prediction is shown to be correct and leads to the discovery of superconductivity in ReGa5. The Fermi levels for endohedral gallide cluster compounds are located in deep pseudogaps in the electronic densities of states, an important factor in determining their chemical stability, while at the same time limiting their superconducting transition temperatures. PMID:26644566

A tectonic model for the spatial occurrence of porphyry copper and polymetallic vein deposits - applications to Central Europe

USGS Publications Warehouse

Drew, Lawrence J.

2006-01-01

A structural-tectonic model, which was developed to assess the occurrence of undiscovered porphyry copper deposits and associated polymetallic vein systems for the Matra Mountains, Hungary, has been expanded here and applied to other parts of central Europe. The model explains how granitoid stocks are emplaced and hydrothermal fluids flow within local strain features (duplexes) within strike-slip fault systems that develop in continental crust above subducting plates. Areas of extension that lack shear at the corners and along the edges of the fault duplexes are structural traps for the granitoid stocks associated with porphyry copper deposits. By contrast, polymetallic vein deposits are emplaced where shear and extension are prevalent in the interior of the duplexes. This model was applied to the Late Cretaceous-age porphyry copper and polymetallic vein deposits in the Banat-Timok-Srednogorie region of Romania-Serbia-Bulgaria and the middle Miocene-age deposits in Romania and Slovakia. In the first area, porphyry copper deposits are most commonly located at the corners, and occasionally along the edges, of strike-slip fault duplexes, and the few polymetallic vein deposits identified are located at interior sites of the duplexes. In the second area, the model accounts for the preferred sites of porphyry copper and polymetallic vein deposits in the Apuseni Mountains (Romania) and central Slovakian volcanic field (Slovakia).

Mechanisms of Pb(II) sorption on a biogenic manganese oxide.

PubMed

Villalobos, Mario; Bargar, John; Sposito, Garrison

2005-01-15

Macroscopic Pb(II) uptake experiments and Pb L3-edge extended X-ray absorption fine structure (EXAFS) spectroscopy were combined to examine the mechanisms of Pb(II) sequestration by a biogenic manganese oxide and its synthetic analogues, all of which are layer-type manganese oxides (phyllomanganates). Relatively fast Pb(II) sorption was observed, as well as extremely high sorption capacities, suggesting Pb incorporation into the structure of the oxides. EXAFS analysis revealed similar uptake mechanisms regardless of the specific nature of the phyllomanganate, electrolyte background, total Pb(II) loading, or equilibration time. One Pb-O and two Pb-Mn shells at distances of 2.30, 3.53, and 3.74 A, respectively, were found, as well as a linear relationship between Brunauer-Emmett-Teller (BET; i.e., external) specific surface area and maximum Pb(II) sorption that also encompassed data from previous work. Both observations support the existence of two bonding mechanisms in Pb(II) sorption: a triple-corner-sharing complex in the interlayers above/ below cationic sheet vacancies (N theoretical = 6), and a double-corner-sharing complex on particle edges at exposed singly coordinated -O(H) bonds (N theoretical = 2). General prevalence of external over internal sorption is predicted, but the two simultaneous sorption mechanisms can account for the widely noted high affinity of manganese oxides for Pb(ll) in natural environments.

Durability study of the US-23 aggregate test road and recent JPCP projects with premature joint deterioration.

DOT National Transportation Integrated Search

2010-12-01

Materials related distress (MRD) characterized by starburst type corner spalling at the longitudinal centerline joint, and occasional transverse joint spalling have developed at a rapid rate in a number of JPCP projects constructed since 1999. ...

Sn–Ag–Cu nanosolders: Melting behavior and phase diagram prediction in the Sn-rich corner of the ternary system

PubMed Central

Roshanghias, Ali; Vrestal, Jan; Yakymovych, Andriy; Richter, Klaus W.; Ipser, Herbert

2015-01-01

Melting temperatures of Sn–Ag–Cu (SAC) alloys in the Sn-rich corner are of interest for lead-free soldering. At the same time, nanoparticle solders with depressed melting temperatures close to the Sn–Pb eutectic temperature have received increasing attention. Recently, the phase stability of nanoparticles has been the subject of plenty of theoretical and empirical investigations. In the present study, SAC nanoparticles of various sizes have been synthesized via chemical reduction and the size dependent melting point depression of these particles has been specified experimentally. The liquidus projection in the Sn-rich corner of the ternary SAC system has also been calculated as a function of particle size, based on the CALPHAD-approach. The calculated melting temperatures were compared with those obtained experimentally and with values reported in the literature, which revealed good agreement. The model also predicts that with decreasing particle size, the eutectic composition shifts towards the Sn-rich corner. PMID:26082567

Interface wave propagation and edge conversion at a low stiffness interphase layer between two solids: A numerical study.

PubMed

Cho, Hideo; Rokhlin, Stanislav I

2015-09-01

The Rayleigh-to-interface wave conversion and the propagation of the resulting symmetric and antisymmetric modes on a bonded interface between solids is analyzed by the two dimensional finite difference time domain method. The propagated patterns were visualized to improve understanding of the phenomena. It is found that the partition of the energy of the interface waves above and below the interface changes repeatedly with propagation distance due to interference between the two modes which have slightly different phase velocities. The destructive interference of those two modes results in dips in the amplitude spectrum of the interface waves, which shift in frequency with propagation distance. The Rayleigh wave received that is created by the interface wave at the exit corner of the joint also shows interference dips in its spectrum. Those dips depend on the interface properties and can potentially be used for interface characterization. Conversion factors related to the interface wave at the upward and downward corners are determined and discussed. As a result, the total transition factor through the upward and downward corners for the interface wave was estimated as 0.37 and would be sufficiently large to probe the interface by coupling from the Rayleigh to the interface wave. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

The End-to-end Demonstrator for improved decision making in the water sector in Europe (EDgE)

NASA Astrophysics Data System (ADS)

Wood, Eric; Wanders, Niko; Pan, Ming; Sheffield, Justin; Samaniego, Luis; Thober, Stephan; Kumar, Rohinni; Prudhomme, Christel; Houghton-Carr, Helen

2017-04-01

High-resolution simulations of water resources from hydrological models are vital to supporting important climate services. Apart from a high level of detail, both spatially and temporally, it is important to provide simulations that consistently cover a range of timescales, from historical reanalysis to seasonal forecast and future projections. In the new EDgE project commissioned by the ECMWF (C3S) we try to fulfill these requirements. EDgE is a proof-of-concept project which combines climate data and state-of-the-art hydrological modelling to demonstrate a water-oriented information system implemented through a web application. EDgE is working with key European stakeholders representative of private and public sectors to jointly develop and tailor approaches and techniques. With these tools, stakeholders are assisted in using improved climate information in decision-making, and supported in the development of climate change adaptation and mitigation policies. Here, we present the first results of the EDgE modelling chain, which is divided into three main processes: 1) pre-processing and downscaling; 2) hydrological modelling; 3) post-processing. Consistent downscaling and bias corrections for historical simulations, seasonal forecasts and climate projections ensure that the results across scales are robust. The daily temporal resolution and 5km spatial resolution ensure locally relevant simulations. With the use of four hydrological models (PCR-GLOBWB, VIC, mHM, Noah-MP), uncertainty between models is properly addressed, while consistency is guaranteed by using identical input data for static land surface parameterizations. The forecast results are communicated to stakeholders via Sectoral Climate Impact Indicators (SCIIs) that have been created in collaboration with the end-user community of the EDgE project. The final product of this project is composed of 15 years of seasonal forecast and 10 climate change projections, all combined with four hydrological models. These unique high-resolution climate information simulations in the EDgE project provide an unprecedented information system for decision-making over Europe.

International Physics Summer Camp for High School Students

NASA Astrophysics Data System (ADS)

Pope, Damian T.; Korsunsky, B.

2006-12-01

Each year for the past three years, Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada, has staged an annual physics summer camp for high school students worldwide. Known as the International Summer School for Young Physicists (ISSYP), it attracts students from all corners of the globe and this year had attendees from 15 countries and 5 continents. The camp is aimed at motivated students around the age of 16 and is a two-week immersion into the exciting world of cutting-edge physics today. It covers topics such as dark matter, superstring theory and quantum computers, and exposes attendees to some of the very latest research results. It includes lectures, tutorials, laboratory visits and small-group projects and, in addition to teaching new material, strives to give students a deeper appreciation of the true nature of science. Throughout, attendees have a great deal of interaction with the institute's scientists. This presentation will give an overview of the camp including the material taught within it, its impact on students and the goals of the program. More information about the camp can be found at: http://www.youngphysicists.ca

Is there a common orientational order for the liquid phase of tetrahedral molecules?

PubMed

Rey, Rossend

2009-08-14

The title question is addressed with molecular dynamics simulations for a broad set of molecules: methane (CH4), neopentane (C(CH3)4), carbon tetrafluoride (CF4), carbon tetrachloride (CCl4), silicon tetrachloride (SiCl4), vanadium tetrachloride (VCl4), tin tetrachloride (SnCl4), carbon tetrabromide (CBr4), and tin tetraiodide (SnI4). In all cases the sequence of most populated relative orientations, for increasing distances, is found to be identical: The closest distances correspond to face-to-face followed by a dominant role of edge-to-face, while for larger distances the main configuration is edge-to-edge. The corner-to-face configuration plays an almost negligible role. The range of orientational order is also similar, with remnants of orientational correlation discernible up to the fourth solvation shell. The equivalence does not only hold in the qualitative terms just stated but is also quantitative to a large extent once the center-center distance is properly scaled.

Is there a common orientational order for the liquid phase of tetrahedral molecules?

NASA Astrophysics Data System (ADS)

Rey, Rossend

2009-08-01

The title question is addressed with molecular dynamics simulations for a broad set of molecules: methane (CH4), neopentane (C(CH3)4), carbon tetrafluoride (CF4), carbon tetrachloride (CCl4), silicon tetrachloride (SiCl4), vanadium tetrachloride (VCl4), tin tetrachloride (SnCl4), carbon tetrabromide (CBr4), and tin tetraiodide (SnI4). In all cases the sequence of most populated relative orientations, for increasing distances, is found to be identical: The closest distances correspond to face-to-face followed by a dominant role of edge-to-face, while for larger distances the main configuration is edge-to-edge. The corner-to-face configuration plays an almost negligible role. The range of orientational order is also similar, with remnants of orientational correlation discernible up to the fourth solvation shell. The equivalence does not only hold in the qualitative terms just stated but is also quantitative to a large extent once the center-center distance is properly scaled.

Directional change in tunneling of subterranean termites (Isoptera: Rhinotermitidae) in response to decayed wood attractants.

PubMed

Su, Nan-Yao

2005-04-01

Wood discs decayed with brown rot fungi and polymer discs impregnated with acetone extract of decayed wood were embedded in sand of a two-dimensional foraging arena to evaluate their attractant potential in directing termite tunnels toward them. Termites were released near one arena corner and were guided to follow the physical guideline of the arena edges. In the absence of the attractants, termites generally formed a relatively linear tunnel along the edges. When decayed wood discs or treated polymer discs were placed in wet sand near one side of the arena, termite tunnels departed from the arena edges and were oriented toward them. The attraction distance ranged from 12 to 18 cm. The attractant properties were most likely water soluble and permeated through wet sand to cause termites to change their orientation. The results demonstrated that when such attractants are placed near a bait station in the field, they may be used to direct termite foraging toward the station.

Robot Acting on Moving Bodies (RAMBO): Interaction with tumbling objects

NASA Technical Reports Server (NTRS)

Davis, Larry S.; Dementhon, Daniel; Bestul, Thor; Ziavras, Sotirios; Srinivasan, H. V.; Siddalingaiah, Madhu; Harwood, David

1989-01-01

Interaction with tumbling objects will become more common as human activities in space expand. Attempting to interact with a large complex object translating and rotating in space, a human operator using only his visual and mental capacities may not be able to estimate the object motion, plan actions or control those actions. A robot system (RAMBO) equipped with a camera, which, given a sequence of simple tasks, can perform these tasks on a tumbling object, is being developed. RAMBO is given a complete geometric model of the object. A low level vision module extracts and groups characteristic features in images of the object. The positions of the object are determined in a sequence of images, and a motion estimate of the object is obtained. This motion estimate is used to plan trajectories of the robot tool to relative locations rearby the object sufficient for achieving the tasks. More specifically, low level vision uses parallel algorithms for image enhancement by symmetric nearest neighbor filtering, edge detection by local gradient operators, and corner extraction by sector filtering. The object pose estimation is a Hough transform method accumulating position hypotheses obtained by matching triples of image features (corners) to triples of model features. To maximize computing speed, the estimate of the position in space of a triple of features is obtained by decomposing its perspective view into a product of rotations and a scaled orthographic projection. This allows use of 2-D lookup tables at each stage of the decomposition. The position hypotheses for each possible match of model feature triples and image feature triples are calculated in parallel. Trajectory planning combines heuristic and dynamic programming techniques. Then trajectories are created using dynamic interpolations between initial and goal trajectories. All the parallel algorithms run on a Connection Machine CM-2 with 16K processors.

Determination of the crystal structure and composition of Li6Be4OH12 by the stochastic method.

PubMed Central

Pauling, L

1990-01-01

Because of the failure to find a structure for LiBeH3 with a face-centered unit cube with edge 5.09 A, the x-ray powder pattern has been reindexed for a body-centered unit cube with edge 7.24 A. Application of the principles of structural chemistry leads to the formula Li6Be4OH12 and to a structure involving Be4OH12 clusters formed by 4 BeOH3 tetrahedra with their O corner shared, Be--(H,O) bond length 1.59 A, and with the clusters joined to one another by Li with octahedral or rectangular-planar coordination of 6 H or 4 H, Li-H bond lengths about 1.92 A. PMID:11607052

Determination of the crystal structure and composition of Li6Be4OH12 by the stochastic method.

PubMed

Pauling, L

1990-01-01

Because of the failure to find a structure for LiBeH3 with a face-centered unit cube with edge 5.09 A, the x-ray powder pattern has been reindexed for a body-centered unit cube with edge 7.24 A. Application of the principles of structural chemistry leads to the formula Li6Be4OH12 and to a structure involving Be4OH12 clusters formed by 4 BeOH3 tetrahedra with their O corner shared, Be--(H,O) bond length 1.59 A, and with the clusters joined to one another by Li with octahedral or rectangular-planar coordination of 6 H or 4 H, Li-H bond lengths about 1.92 A.

Heat transfer to four fineness-ratio-1.6 hexagonal prisms with various corner radii at Mach 6

NASA Technical Reports Server (NTRS)

Hunt, J. L.

1972-01-01

An investigation was conducted in the Langley 20-inch Mach 6 tunnel to define the aerodynamic heat transfer to the radioisotope fuel cask (heat source) of the SNAP-19/Pioneer power system. The shape of the SNAP-19/Pioneer heat source is that of a hexagonal prism with flat ends; the fineness ratio, based on maximum (edge to edge) diameter, is 1.61. Phase-change-paint heat-transfer data and schlieren photographs were obtained on four possible 1/2-scale entry configurations of the SNAP-19/Pioneer heat source. Tests were conducted over a wide range of attitudes and at nominal Reynolds numbers, based on the length of the unablated configuration, of 33,000; 84,000; and 2,200,000.

Timing discriminator using leading-edge extrapolation

DOEpatents

Gottschalk, Bernard

1983-01-01

A discriminator circuit to recover timing information from slow-rising pulses by means of an output trailing edge, a fixed time after the starting corner of the input pulse, which is nearly independent of risetime and threshold setting. This apparatus comprises means for comparing pulses with a threshold voltage; a capacitor to be charged at a certain rate when the input signal is one-third threshold voltage, and at a lower rate when the input signal is two-thirds threshold voltage; current-generating means for charging the capacitor; means for comparing voltage capacitor with a bias voltage; a flip-flop to be set when the input pulse reaches threshold voltage and reset when capacitor voltage reaches the bias voltage; and a clamping means for discharging the capacitor when the input signal returns below one-third threshold voltage.

Near vertical view of Lubbock area in west Texas as seen from Apollo 9

NASA Image and Video Library

1969-03-11

AS09-23-3561 (3-13 March 1969) --- Near vertical view of the Lubbock area in west Texas as photographed from the Apollo 9 spacecraft during its Earth-orbital mission. Conspicuous patterns of farmland surround the city and extend eastward (up) to the Caprock Escarpment. The Double Mountain fork of the Brazos River drains east (toward upper center); Leeland is at lower center; Brownfield at lower right. The sharp edge of a cloud disk cuts across the upper right corner.

22. 1988 aerial of Tempe Canal, Sections 9, 16 and ...

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

22. 1988 aerial of Tempe Canal, Sections 9, 16 and 17 (T1N R5E) (left of page is north). Tempe Crosscut enters from center left. The Trunk Ditch right of way is visible just north of Mesa Country Club as a gray line running along the edge of a vacant lot. The Salt River bed is in the upper left corner. Photographer: Unknown, 1988. Source: SRP Cartographic Drafting - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

Singularities of the quad curl problem

NASA Astrophysics Data System (ADS)

Nicaise, Serge

2018-04-01

We consider the quad curl problem in smooth and non smooth domains of the space. We first give an augmented variational formulation equivalent to the one from [25] if the datum is divergence free. We describe the singularities of the variational space which correspond to the ones of the Maxwell system with perfectly conducting boundary conditions. The edge and corner singularities of the solution of the corresponding boundary value problem with smooth data are also characterized. We finally obtain some regularity results of the variational solution.

Making a georeferenced mosaic of historical map series using constrained polynomial fit

NASA Astrophysics Data System (ADS)

Molnár, G.

2009-04-01

Present day GIS software packages make it possible to handle several hundreds of rasterised map sheets. For proper usage of such datasets we usually have two requirements: First these map sheets should be georeferenced, secondly these georeferenced maps should fit properly together, without overlap and short. Both requirements can be fulfilled easily, if the geodetic background for the map series is accurate, and the projection of the map series is known. In this case the individual map sheets should be georeferenced in the projected coordinate system of the map series. This means every individual map sheets are georeferenced using overprinted coordinate grid or image corner projected coordinates as ground control points (GCPs). If after this georeferencing procedure the map sheets do not fit together (for example because of using different projection for every map sheet, as it is in the case of Third Military Survey) a common projection can be chosen, and all the georeferenced maps should be transformed to this common projection using a map-to-map transformation. If the geodetic background is not so strong, ie. there are distortions inside the map sheets, a polynomial (linear quadratic or cubic) polynomial fit can be used for georeferencing the map sheets. Finding identical surface objects (as GCPs) on the historical map and on a present day cartographic map, let us to determine a transformation between raw image coordinates (x,y) and the projected coordinates (Easting, Northing, E,N). This means, for all the map sheets, several GCPs should be found, (for linear, quadratic of cubic transformations at least 3, 5 or 10 respectively) and every map sheets should be transformed to a present day coordinate system individually using these GCPs. The disadvantage of this method is that, after the transformation, the individual transformed map sheets not necessarily fit together properly any more. To overcome this problem neither the reverse order of procedure helps: if we make the mosaic first (eg. graphically) and we try the polynomial fit of this mosaic afterwards, neither using this can we reduce the error of internal inaccuracy of the map-sheets. We can overcome this problem by calculating the transformation parameters of polynomial fit with constrains (Mikhail, 1976). The constrain is that the common edge of two neighboring map-sheets should be transformed identically, ie. the right edge of the left image and the left edge of the right image should fit together after the transformation. This condition should fulfill for all the internal (not only the vertical, but also for the horizontal) edges of the mosaic. Constrains are expressed as a relationship between parameters: The parameters of the polynomial transformation should fulfill not only the least squares adjustment criteria but also the constrain: the transformed coordinates should be identical on the image edges. (With the example mentioned above, for image points of the rightmost column of the left image the transformed coordinates should be the same a for the image points of the leftmost column of the right image, and these transformed coordinates can depend on the line number image coordinate of the raster point.) The normal equation system can be calculated with Lagrange-multipliers. The resulting set of parameters for all map-sheets should be applied on the transformation of the images. This parameter set can not been directly applied in GIS software for the transformation. The simplest solution applying this parameters is ‘simulating' GCPs for every image, and applying these simulated GCPs for the georeferencing of the individual map sheets. This method is applied on a set of map-sheets of the First military Survey of the Habsburg Empire with acceptable results. Reference: Mikhail, E. M.: Observations and Least Squares. IEP—A Dun-Donnelley Publisher, New York, 1976. 497 pp.

Unsteady aerodynamics and vortex-sheet formation of a two-dimensional airfoil

NASA Astrophysics Data System (ADS)

Xia, X.; Mohseni, K.

2017-11-01

Unsteady inviscid flow models of wings and airfoils have been developed to study the aerodynamics of natural and man-made flyers. Vortex methods have been extensively applied to reduce the dimensionality of these aerodynamic models, based on the proper estimation of the strength and distribution of the vortices in the wake. In such modeling approaches, one of the most fundamental questions is how the vortex sheets are generated and released from sharp edges. To determine the formation of the trailing-edge vortex sheet, the classical Kutta condition can be extended to unsteady situations by realizing that a flow cannot turn abruptly around a sharp edge. This condition can be readily applied to a flat plate or an airfoil with cusped trailing edge since the direction of the forming vortex sheet is known to be tangential to the trailing edge. However, for a finite-angle trailing edge, or in the case of flow separation away from a sharp corner, the direction of the forming vortex sheet is ambiguous. To remove any ad-hoc implementation, the unsteady Kutta condition, the conservation of circulation, as well as the conservation laws of mass and momentum are coupled to analytically solve for the angle, strength, and relative velocity of the trailing-edge vortex sheet. The two-dimensional aerodynamic model together with the proposed vortex-sheet formation condition is verified by comparing flow structures and force calculations with experimental results for airfoils in steady and unsteady background flows.

Membrane triangles with corner drilling freedoms. III - Implementation and performance evaluation

NASA Technical Reports Server (NTRS)

Felippa, Carlos A.; Alexander, Scott

1992-01-01

This paper completes a three-part series on the formulation of 3-node, 9-dof membrane triangles with corner drilling freedoms based on parametrized variational principles. The first four sections cover element implementation details including determination of optimal parameters and treatment of distributed loads. Then three elements of this type, labeled ALL, FF and EFF-ANDES, are tested on standard plane stress problems. ALL represents numerically integrated versions of Allman's 1988 triangle; FF is based on the free formulation triangle presented by Bergan and Felippa in 1985; and EFF-ANDES represent two different formulations of the optimal triangle derived in Parts I and II. The numerical studies indicate that the ALL, FF and EFF-ANDES elements are comparable in accuracy for elements of unitary aspect ratios. The ALL elements are found to stiffen rapidly in inplane bending for high aspect ratios, whereas the FF and EFF elements maintain accuracy. The EFF and ANDES implementations have a moderate edge in formation speed over the FF.

Effects of rat sex differences and lighting on locomotor exploration of a circular open field with free-standing central corners and without peripheral walls.

PubMed

Alstott, Jeff; Timberlake, William

2009-01-23

A typical open field consists of a square enclosure, bounded by four straight walls joined by identical corners. For decades behavioral researchers have used the open center and more sheltered perimeter of such fields to examine the effects of drugs, sex differences, and illumination on the behavioral expression of fear and anxiety. The present study "reversed" the relative security of the center and periphery of a circular field to re-examine the functional relation of open field behavior to experience, sex differences and lighting. Across six daily exposures, males in both the light and dark rapidly increased their preference for the center. Females in the light developed a similar pattern, though more slowly; females in the dark continued to spend the great majority of their time in the open periphery, including the edge of the field. The behavior of all groups, but especially the dark females, strongly supports the continued importance of environmental assessment in open field behavior.

STS-57 Earth observation of the Eastern Mediterranean, Nile River, Asia Minor

NASA Technical Reports Server (NTRS)

1993-01-01

STS-57 Earth observation of the Eastern Mediterranean. From a high vantage point over the Nile River, this north-looking view shows the eastern Mediterranean and the entire landmass of Asia Minor, with the Black Sea dimly visible at the horizon. Many of the Greek islands can be seen in the Aegean Sea (top left), off the coast of Asia Minor. Cyprus is visible under atmospheric dust in the northeastern corner of the Mediterranean. The dust cloud covers the east end of the Mediterranean, its western edge demarcated by a line that cuts the center of the Nile Delta. This dust cloud originated far to the west, in Algeria, and moved northeast. A gyre of clouds in the southeast corner of the Mediterranean indicates a complementary counterclockwise (cyclonic) circulation of air. The Euphrates River appears as a thin green line (upper right) in the yellow Syrian desert just south of the mountains of Turkey. The Dead Sea (lower right) lies in a rift valley which extends north into Turkey and sout

Trigonometrical sums connected with the chiral Potts model, Verlinde dimension formula, two-dimensional resistor network, and number theory

NASA Astrophysics Data System (ADS)

Chair, Noureddine

2014-02-01

We have recently developed methods for obtaining exact two-point resistance of the complete graph minus N edges. We use these methods to obtain closed formulas of certain trigonometrical sums that arise in connection with one-dimensional lattice, in proving Scott's conjecture on permanent of Cauchy matrix, and in the perturbative chiral Potts model. The generalized trigonometrical sums of the chiral Potts model are shown to satisfy recursion formulas that are transparent and direct, and differ from those of Gervois and Mehta. By making a change of variables in these recursion formulas, the dimension of the space of conformal blocks of SU(2) and SO(3) WZW models may be computed recursively. Our methods are then extended to compute the corner-to-corner resistance, and the Kirchhoff index of the first non-trivial two-dimensional resistor network, 2×N. Finally, we obtain new closed formulas for variant of trigonometrical sums, some of which appear in connection with number theory.

Combined Aero and Underhood Thermal Analysis for Heavy Duty Trucks

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

Vegendla, Prasad; Sofu, Tanju; Saha, Rohit

2017-01-31

Aerodynamic analysis of the medium-duty delivery truck was performed to achieve vehicle design optimization. Three dimensional CFD simulations were carried out for several improved designs, with a detailed external component analysis of wheel covers, side skirts, roof fairings, and rounded trailer corners. The overall averaged aerodynamics drag reduction through the design modifications were shown up to 22.3% through aerodynamic considerations alone, which is equivalent to 11.16% fuel savings. The main identified fuel efficiencies were based on second generation devices, including wheel covers, side skirts, roof fairings, and rounded trailer corners. The important findings of this work were; (i) the optimummore » curvature radius of the rounded trailer edges found to be 125 mm, with an arc length of 196.3 mm, (ii) aerodynamic drag reduction increases with dropping clearance of side skirts between wheels and ground, and (iii) aerodynamic drag reduction increases with an extension of front bumper towards the ground.« less

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.

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.

Measurement of damping of graphite epoxy materials

NASA Technical Reports Server (NTRS)

Crocker, M. J.

1985-01-01

The design of an experiment to measure the damping of a cylindrical graphite-epoxy specimen with a three point support and a knife edge support is described as well as equipment used in tests conducted to determine the influence of the support at the two ends of the specimen and to simulate an idealized free-free boundary condition at the two edges. A curve fitting technique is being used to process the frequency response data obtained. Experiments conducted on the thin plate specimen also reveal the influence of the end support condition on the damping ratio of the specimen. The damping ratio values measured for both specimens appear to be strongly influenced by the shape of the specimen and appear to depend on length and fiber orientation as well as the presence of discontinuities such as sharp bends, corners, and notches.

Timing discriminator using leading-edge extrapolation

DOEpatents

Gottschalk, B.

1981-07-30

A discriminator circuit to recover timing information from slow-rising pulses by means of an output trailing edge, a fixed time after the starting corner of the input pulse, which is nearly independent of risetime and threshold setting is described. This apparatus comprises means for comparing pulses with a threshold voltage; a capacitor to be charged at a certain rate when the input signal is one-third threshold voltage, and at a lower rate when the input signal is two-thirds threshold voltage; current-generating means for charging the capacitor; means for comparing voltage capacitor with a bias voltage; a flip-flop to be set when the input pulse reaches threshold voltage and reset when capacitor voltage reaches the bias voltage; and a clamping means for discharging the capacitor when the input signal returns below one-third threshold voltage.

Crafty Corner.

ERIC Educational Resources Information Center

Naturescope, 1986

1986-01-01

Contains three projects that relate to plants and animals of wetlands. Includes instructions and patterns for making cattails, pitcher plants (that really catch flies), and stand-up wetland animals such as insects, birds, crabs, and alligators. (TW)

Anion-Anion Bonding and Topology in Ternary Iridium Seleno-Stannides.

PubMed

Trump, Benjamin A; Tutmaher, Jake A; McQueen, Tyrel M

2015-12-21

The synthesis and physical properties of two new and one known Ir-Sn-Se compound are reported. Their crystal structures are elucidated with transmission electron microscopy and powder X-ray diffraction. IrSn0.45Se1.55 is a pyrite phase which consists of tilted corner-sharing IrX6 octahedra with randomly distributed (Sn-Se)(4-) and (Se-Se)(2-) dimers. Ir2Sn3Se3 is a known trigonally distorted skutterudite that consists of cooperatively tilted corner-sharing IrSn3Se3 octahedra with ordered (Sn-Se)2(4-) tetramers. Ir2SnSe5 is a layered, distorted β-MnO2 (pyrolusite) structure consisting of a double IrSe6 octrahedral row, corner sharing in the a direction and edge sharing in the b direction. This distorted pyrolusite contains (Se-Se)(2-) dimers and Se(2-) anions, and each double row is "capped" with a (Sn-Se)n polymeric chain. Resistivity, specific heat, and magnetization measurements show that all three have insulating and diamagnetic behavior, indicative of low-spin 5d(6) Ir(3+). Electronic structure calculations on Ir2Sn3Se3 show a single, spherical, nonspin-orbit split valence band and suggest that Ir2Sn3Se3 is topologically nontrivial under tensile strain due to inversion of Ir-d and Se-p states.

Anion–Anion Bonding and Topology in Ternary Iridium Seleno–Stannides

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

Trump, Benjamin A.; Tutmaher, Jake A.; McQueen, Tyrel M.

2015-12-21

The synthesis and physical properties of two new and one known Ir–Sn–Se compound are reported. Their crystal structures are elucidated with transmission electron microscopy and powder X-ray diffraction. IrSn0.45Se1.55 is a pyrite phase which consists of tilted corner-sharing IrX6 octahedra with randomly distributed (Sn–Se)4– and (Se–Se)2– dimers. Ir2Sn3Se3 is a known trigonally distorted skutterudite that consists of cooperatively tilted corner-sharing IrSn3Se3 octahedra with ordered (Sn–Se)24– tetramers. Ir2SnSe5 is a layered, distorted β-MnO2 (pyrolusite) structure consisting of a double IrSe6 octrahedral row, corner sharing in the a direction and edge sharing in the b direction. This distorted pyrolusite contains (Se–Se)2– dimersmore » and Se2– anions, and each double row is “capped” with a (Sn–Se)n polymeric chain. Resistivity, specific heat, and magnetization measurements show that all three have insulating and diamagnetic behavior, indicative of low-spin 5d6 Ir3+. Electronic structure calculations on Ir2Sn3Se3 show a single, spherical, nonspin–orbit split valence band and suggest that Ir2Sn3Se3 is topologically nontrivial under tensile strain due to inversion of Ir-d and Se-p states.« less

76 FR 2648 - Hand Trucks and Certain Parts Thereof From the People's Republic of China: Preliminary Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-14

... the vertical frame, the handling area and the projecting edges or toe plate, and any combination... edge or edges, or toe plate, perpendicular or angled to the vertical frame, at or near the lower section of the vertical frame. The projecting edge or edges, or toe plate, slides under a load for...

Modeling of turbulent separated flows for aerodynamic applications

NASA Technical Reports Server (NTRS)

Marvin, J. G.

1983-01-01

Steady, high speed, compressible separated flows modeled through numerical simulations resulting from solutions of the mass-averaged Navier-Stokes equations are reviewed. Emphasis is placed on benchmark flows that represent simplified (but realistic) aerodynamic phenomena. These include impinging shock waves, compression corners, glancing shock waves, trailing edge regions, and supersonic high angle of attack flows. A critical assessment of modeling capabilities is provided by comparing the numerical simulations with experiment. The importance of combining experiment, numerical algorithm, grid, and turbulence model to effectively develop this potentially powerful simulation technique is stressed.

Computer vision

NASA Technical Reports Server (NTRS)

Gennery, D.; Cunningham, R.; Saund, E.; High, J.; Ruoff, C.

1981-01-01

The field of computer vision is surveyed and assessed, key research issues are identified, and possibilities for a future vision system are discussed. The problems of descriptions of two and three dimensional worlds are discussed. The representation of such features as texture, edges, curves, and corners are detailed. Recognition methods are described in which cross correlation coefficients are maximized or numerical values for a set of features are measured. Object tracking is discussed in terms of the robust matching algorithms that must be devised. Stereo vision, camera control and calibration, and the hardware and systems architecture are discussed.

Apollo 9 Mission image - S0-65 Multispectral Photography - California and Mexico

NASA Image and Video Library

1969-03-12

AS09-26A-3799A (12 March 1969) --- Color infrared photograph of the Salton Sea and Imperial Valley area of Southern California as seen from the Apollo 9 spacecraft. This picture was taken as a part of the SO-65 Multispectral Terrain Photography Experiment. On the eastern edge of the picture are the Colorado River and a small portion of Arizona. Yuma, Arizona, is at the bottom right corner. The cities of El Centro, California, and Mexicali, Mexico, are at the bottom center.

WMSA for wireless communication applications

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

Vats, Monika; Agarwal, Alok, E-mail: alokagarwal26@yahoo.com; Kumar, Ravindra

2016-03-09

Modified rectangular compact microstrip patch antenna having finite ground plane is proposed in this paper. Wideband Microstrip Antenna (WMSA) is achieved by corner cut and inserting air gaps inside the edges of the radiating patch having finite ground plane. The obtained impedance bandwidth for 10 dB return loss for the operating frequency f{sub 0} = 2.09 GHz is 28.7 % (600 MHz), which is very high as compared to the bandwidth obtained for the conventional microstrip antenna. Compactness with wide bandwidth of this antenna is practically useful for the wireless communication systems.

Precise seismic velocity structure beneath the Hokkaido corner, northern Japan: Arc-arc collision and the 1970 M 6.7 Hidaka region earthquake and the 1982 M 7.1 Urakawa-oki earthquake

NASA Astrophysics Data System (ADS)

Kita, S.; Hasegawa, A.; Nakajima, J.; Okada, T.; Matsuzawa, T.; Katsumata, K.

2011-12-01

Using arrival-time data both from the nationwide Kiban seismic network and from a dense temporary seismic network covering the area of the Hokkaido corner [Katsumata et al., 2002a; 2003, JGR], we precisely determined three-dimensional seismic velocity structure beneath this area to understand the collision process between the Kuril and northeasetern Japan forearcs. Tomographic inversions were performed with smaller grid spacing [5 x 10 x 5 km] than our previous study [Kita et al., 2010b, EPSL] by using the double-difference tomography method [Zhang and Thurber, 2003; 2006]. Inhomogeneous seismic velocity structure was more precisely imaged in the Hokkaido corner at depths of 0-120 km. A broad low-velocity zone of P- and S- waves having velocities of crust materials with a total volume of 80 km x 100 km x 50 km is distributed to the west of the Hidaka metamorphic belt (the Hidaka main thrust) at depths of 30-90km. On the other hand, several small-scale high-velocity zones having velocities of mantle materials were detected at depths of 0-35 km), inclined east-northeastward at a high angle of 40-60 degrees. All of these anomaly high velocity zones are respectively located in the deeper extension of the Neogene thrust faults, striking almost N-S direction and dipping 40-50 degrees at depths of 0-10km [e.g. Ito 2000]. The largest high-velocity zone is located in the deeper extension of the Hidaka main thrust, being in contact with the eastern edge of the low-V zone. This high-V zone reaches near the surface at the Hidaka metamorphic belt and its southern edge is located just beneath the Horoman-peridotite, which is one of the most famous peridotite outcrops. Moreover, the boundary of the high-V zone with the broad low-V zone corresponds to the fault plane of the 1970 Mj 6.7 Hidaka region earthquake [Moriya 1972]. Another high-V zone is located within the broad low-V zone at depths of 20-30km and in the deeper extension of thrust, which belongs to the Ishikari Low land eastern edge fault groups. The western boundary of this small high-V zone corresponds to the fault plane of the 1982 Mj 7.1 Urakawa-oki earthquake [Moriya et al, 1983]. Both of the hanging walls of the fault planes of two M 7 class big earthquakes have anomalously high velocities, while both of the foot walls have low velocities. A considerable number of earthquakes, including aftershocks of these two big earthquake and, occur in the broad low-V zone at depths of 0-80 km (even at depths of the mantle wedge), whereas seismicity is very low in other areas. These present observations provide important in formation to deepen our understanding of the ongoing arc-arc collision process and earthquake generation mechanism in the Hokkaido corner.

Structure of short-range-ordered iron(III)-precipitates formed by iron(II) oxidation in water containing phosphate, silicate, and calcium

NASA Astrophysics Data System (ADS)

Voegelin, A.; Frommer, J.; Vantelon, D.; Kaegi, R.; Hug, S. J.

2009-04-01

The oxidation of Fe(II) in water leads to the formation of Fe(III)-precipitates that strongly affect the fate of nutrients and contaminants in natural and engineered systems. Examples include the cycling of As in rice fields irrigated with As-rich groundwater or the treatment of drinking water for As removal. Knowledge of the types of Fe(III)-precipitates forming in such systems is essential for the quantitative modeling of nutrient and contaminant dynamics and for the optimization of water purification techniques on the basis of a mechanistic understanding of the relevant biogeochemical processes. In this study, we investigated the local coordination of Fe, P, and Ca in Fe(III)-precipitates formed by aeration of synthetic Fe(II)-containing groundwater with variable composition (pH 7, 2-30 mg/L Fe(II), 2-20 mg/L phosphate-P, 2-20 mg/L silicate-Si, 8 mM Na-bicarbonate or 2.5 mM Ca-&1.5 mM Mg-bicarbonate). After 4 hours of oxidation, Fe(III)-precipitates were collected on 0.2 µm nylon filters and dried. The precipitates were analyzed by Fe K-edge EXAFS (XAS beamline, ANKA, Germany) and by P and Ca K-edge XANES spectroscopy (LUCIA beamline, SLS, Switzerland). The Fe K-edge EXAFS spectra indicated that local Fe coordination in the precipitates systematically shifted with water composition. As long as water contained P, mainly short-range-ordered Fe(III)-phosphate formed (with molar P/Fe ~0.5). In the absence of P, Fe(III) precipitated as hydrous ferric oxide at high Si/Fe>0.5, as ferrihydrite at intermediate Si/Fe, and mainly as lepidocrocite at Si/Fe<0.2. Analysis of the EXAFS by shell-fitting indicated that Fe(III)-phosphates mainly contained mono- or oligomeric (edge- or corner-sharing) Fe and that the linkage between neighboring Fe(III)-octahedra changed from predominantly edge-sharing in Si-rich hydrous ferric oxide to edge- and corner-sharing in ferrihydrite. Electron microscopic data showed that changes in local precipitate structure were systematically reflected in particle morphology and SAED patterns. The P K-edge XANES spectra revealed that phosphate was bound to both Fe as well as Ca (if present). The Ca K-edge XANES spectra showed that the mode of Ca uptake by the Fe(III)-precipitates shifted from mainly adsorption at high Fe/P to coprecipitation at low Fe/P ratio. Despite oversaturation, neither calcite nor hydroxyapatite formed to a significant extent. The results from this study indicated that, depending on water composition, Fe(II) oxidation in natural waters leads to different types of short-range-ordered Fe(III)-phases. Since these phases are expected to differ in their effect on contaminant and nutrient dynamics, their specific physical and chemical properties warrant further research. Methodologically, this work demonstrated the usefulness of investigating the local structure of short-range-ordered precipitates along compositional gradients and by combining the element-selective information from different X-ray absorption edges.

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...

TreeRipper web application: towards a fully automated optical tree recognition software.

PubMed

Hughes, Joseph

2011-05-20

Relationships between species, genes and genomes have been printed as trees for over a century. Whilst this may have been the best format for exchanging and sharing phylogenetic hypotheses during the 20th century, the worldwide web now provides faster and automated ways of transferring and sharing phylogenetic knowledge. However, novel software is needed to defrost these published phylogenies for the 21st century. TreeRipper is a simple website for the fully-automated recognition of multifurcating phylogenetic trees (http://linnaeus.zoology.gla.ac.uk/~jhughes/treeripper/). The program accepts a range of input image formats (PNG, JPG/JPEG or GIF). The underlying command line c++ program follows a number of cleaning steps to detect lines, remove node labels, patch-up broken lines and corners and detect line edges. The edge contour is then determined to detect the branch length, tip label positions and the topology of the tree. Optical Character Recognition (OCR) is used to convert the tip labels into text with the freely available tesseract-ocr software. 32% of images meeting the prerequisites for TreeRipper were successfully recognised, the largest tree had 115 leaves. Despite the diversity of ways phylogenies have been illustrated making the design of a fully automated tree recognition software difficult, TreeRipper is a step towards automating the digitization of past phylogenies. We also provide a dataset of 100 tree images and associated tree files for training and/or benchmarking future software. TreeRipper is an open source project licensed under the GNU General Public Licence v3.

Automatic classification of singular elements for the electrostatic analysis of microelectromechanical systems

NASA Astrophysics Data System (ADS)

Su, Y.; Ong, E. T.; Lee, K. H.

2002-05-01

The past decade has seen an accelerated growth of technology in the field of microelectromechanical systems (MEMS). The development of MEMS products has generated the need for efficient analytical and simulation methods for minimizing the requirement for actual prototyping. The boundary element method is widely used in the electrostatic analysis for MEMS devices. However, singular elements are needed to accurately capture the behavior at singular regions, such as sharp corners and edges, where standard elements fail to give an accurate result. The manual classification of boundary elements based on their singularity conditions is an immensely laborious task, especially when the boundary element model is large. This process can be automated by querying the geometric model of the MEMS device for convex edges based on geometric information of the model. The associated nodes of the boundary elements on these edges can then be retrieved. The whole process is implemented in the MSC/PATRAN platform using the Patran Command Language (the source code is available as supplementary data in the electronic version of this journal issue).

Robust mosiacs of close-range high-resolution images

NASA Astrophysics Data System (ADS)

Song, Ran; Szymanski, John E.

2008-03-01

This paper presents a robust algorithm which relies only on the information contained within the captured images for the construction of massive composite mosaic images from close-range and high-resolution originals, such as those obtained when imaging architectural and heritage structures. We first apply Harris algorithm to extract a selection of corners and, then, employ both the intensity correlation and the spatial correlation between the corresponding corners for matching them. Then we estimate the eight-parameter projective transformation matrix by the genetic algorithm. Lastly, image fusion using a weighted blending function together with intensity compensation produces an effective seamless mosaic image.

Fuel cell separator plate with bellows-type sealing flanges

DOEpatents

Louis, G.A.

1984-05-29

A fuel cell separator includes a rectangular flat plate having two unitary upper sealing flanges respectively comprising opposite marginal edges of the plate folded upwardly and back on themselves and two lower sealing flanges respectively comprising the other two marginal edges of the plate folded downwardly and back on themselves. Each of the sealing flanges includes a flat wall spaced from the plate and substantially parallel thereto and two accordion-pleated side walls, one of which interconnects the flat wall with the plate and the other of which steps just short of the plate, these side walls affording resilient compressibility to the sealing flange in a direction generally normal to the plane of the plate. Four corner members close the ends of the sealing flanges. An additional resiliently compressible reinforcing member may be inserted in the passages formed by each of the sealing flanges with the plate.

Oxygen evolution on a SrFeO3 anode - Mechanistic considerations from molecular orbital theory

NASA Technical Reports Server (NTRS)

Mehandru, S. P.; Anderson, Alfred B.

1989-01-01

Various pathways proposed in the literature for the evolution of O2 in electrochemical oxidations are explored using the atom superposition and electron delocalization molecular orbital (ASED-MO) theory and the cluster models of the SrFeO3 surface as a prototype material. Calculations indicate that oxygen atoms can be easily formed on the (100) surface as well as on the edge cation sites of a SrFeO3 anode by the discharge of OH(-), followed by its deprotonation and electron transfer to the electrode. The O atoms can form O2 on the edge and corner sites, where the Fe(4+) is coordinated to four and three bulk oxygen anions, respectively. The calculations strongly disfavor mechanisms involving coupling of oxygen atoms adsorbed on different cations as well as a mechanism featuring an ozone intermediate.

Tailoring graphene magnetism by zigzag triangular holes: A first-principles thermodynamics study

DOE PAGES

Khan, Muhammad Ejaz; Zhang, P.; Sun, Yi -Yang; ...

2016-03-30

In this study, we discuss the thermodynamic stability and magnetic property of zigzag triangular holes (ZTHs) in graphene based on the results of first-principles density functional theory calculations. We find that ZTHs with hydrogen-passivated edges in mixed sp 2/sp 3 configurations (z 211) could be readily available at experimental thermodynamic conditions, but ZTHs with 100% sp 2 hydrogen-passivation (z 1) could be limitedly available at high temperature and ultra-high vacuum conditions. Graphene magnetization near the ZTHs strongly depends on the type and the size of the triangles. While metallic z 1 ZTHs exhibit characteristic edge magnetism due to the same-sublatticemore » engineering, semiconducting z 211 ZTHs do show characteristic corner magnetism when the size is small < 2 nm. Our findings could be useful for experimentally tailoring metal-free carbon magnetism by simply fabricating triangular holes in graphene.« less

Role of Tool Shoulder End Features on Friction Stir Weld Characteristics of 6082 Aluminum Alloy

NASA Astrophysics Data System (ADS)

Mugada, Krishna Kishore; Adepu, Kumar

2018-03-01

Understanding the temperature generation around the tool shoulder contact is one of the important aspects of the friction stir welding process. In the present study, the effects of various tool shoulder end feature on the temperature and mechanical properties of the 6082 aluminum alloy were investigated. The experimental results show that the axial force during the welding is considerably reduced by using tools with shoulder end features. The detailed observation revealed that around the tool shoulder contact, the amount of heat generation is higher between trialing edge (TE) to retreating side-leading edge corner (RS-LE) counter clockwise direction and lower between RS-LE to TE clockwise direction. Out of the four shoulder end featured tools, the welds produced with ridges shoulder tool resulted in superior properties with significantly lower axial force (approximately 32%) compared to plane shoulder tool.

Tailoring graphene magnetism by zigzag triangular holes: A first-principles thermodynamics study

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

Khan, Muhammad Ejaz; Zhang, P.; Kim, Yong-Hyun, E-mail: yong.hyun.kim@kaist.ac.kr

We discuss the thermodynamic stability and magnetic property of zigzag triangular holes (ZTHs) in graphene based on the results of first-principles density functional theory calculations. We find that ZTHs with hydrogen-passivated edges in mixed sp{sup 2}/sp{sup 3} configurations (z{sub 211}) could be readily available at experimental thermodynamic conditions, but ZTHs with 100% sp{sup 2} hydrogen-passivation (z{sub 1}) could be limitedly available at high temperature and ultra-high vacuum conditions. Graphene magnetization near the ZTHs strongly depends on the type and the size of the triangles. While metallic z{sub 1} ZTHs exhibit characteristic edge magnetism due to the same-sublattice engineering, semiconducting z{submore » 211} ZTHs do show characteristic corner magnetism when the size is small <2 nm. Our findings could be useful for experimentally tailoring metal-free carbon magnetism by simply fabricating triangular holes in graphene.« less

Deterministic blade row interactions in a centrifugal compressor stage

NASA Technical Reports Server (NTRS)

Kirtley, K. R.; Beach, T. A.

1991-01-01

The three-dimensional viscous flow in a low speed centrifugal compressor stage is simulated using an average passage Navier-Stokes analysis. The impeller discharge flow is of the jet/wake type with low momentum fluid in the shroud-pressure side corner coincident with the tip leakage vortex. This nonuniformity introduces periodic unsteadiness in the vane frame of reference. The effect of such deterministic unsteadiness on the time-mean is included in the analysis through the average passage stress, which allows the analysis of blade row interactions. The magnitude of the divergence of the deterministic unsteady stress is of the order of the divergence of the Reynolds stress over most of the span, from the impeller trailing edge to the vane throat. Although the potential effects on the blade trailing edge from the diffuser vane are small, strong secondary flows generated by the impeller degrade the performance of the diffuser vanes.

Fuel cell separator plate with bellows-type sealing flanges

DOEpatents

Louis, George A.

1986-08-05

A fuel cell separator includes a rectangular flat plate having two unitary upper sealing flanges respectively comprising opposite marginal edges of the plate folded upwardly and back on themselves and two lower sealing flanges respectively comprising the other two marginal edges of the plate folded downwardly and back on themselves. Each of the sealing flanges includes a flat wall spaced from the plate and substantially parallel thereto and two accordion-pleated side walls, one of which interconnects the flat wall with the plate and the other of which stops just short of the plate, these side walls affording resilient compressibility to the sealing flange in a directiongenerally normal to the plane of the plate. Four corner members close the ends of the sealing flanges. An additional resiliently compressible reinforcing member may be inserted in the passages formed by each of the sealing flanges with the plate.

Manganese Vanadate Chemistry in Hydrothermal BaF 2 Brines: Ba 3 Mn 2 (V 2 O 7 ) 2 F 2 and Ba 7 Mn 8 O 2 (VO 4 ) 2 F 23

DOE PAGES

Sanjeewa, Liurukara D.; McMillen, Colin D.; McGuire, Michael A.; ...

2016-12-05

We synthesized manganese vanadate fluorides using high-temperature hydrothermal techniques with BaF 2 as a mineralizer. Ba 3Mn 2(V 2O 7) 2F 2 crystallizes in space group C2/c and consists of dimers built from edge-sharing MnO 4F 2 trigonal prisms with linking V 2O 7 groups. Ba 7Mn 8O 2(VO 4) 2F 23 crystallizes in space group Cmmm, with a manganese oxyfluoride network built from edge- and corner-sharing Mn 2+/3+(O,F) 6 octahedra. The resulting octahedra form alternating Mn 2+ and Mn 2+/3+ layers separated by VO 4 tetrahedra. This latter compound exhibits a canted antiferromagnetic order below TN = 25 K.

Magnetic Binary Silicide Nanostructures.

PubMed

Goldfarb, Ilan; Cesura, Federico; Dascalu, Matan

2018-05-02

In spite of numerous advantageous properties of silicides, magnetic properties are not among them. Here, the magnetic properties of epitaxial binary silicide nanostructures are discussed. The vast majority of binary transition-metal silicides lack ferromagnetic order in their bulk-size crystals. Silicides based on rare-earth metals are usually weak ferromagnets or antiferromagnets, yet both groups tend to exhibit increased magnetic ordering in low-dimensional nanostructures, in particular at low temperatures. The origin of this surprising phenomenon lies in undercoordinated atoms at the nanostructure extremities, such as 2D (surfaces/interfaces), 1D (edges), and 0D (corners) boundaries. Uncompensated superspins of edge atoms increase the nanostructure magnetic shape anisotropy to the extent where it prevails over its magnetocrystalline counterpart, thus providing a plausible route toward the design of a magnetic response from nanostructure arrays in Si-based devices, such as bit-patterned magnetic recording media and spin injectors. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrable subsectors from holography

NASA Astrophysics Data System (ADS)

de Mello Koch, Robert; Kim, Minkyoo; Van Zyl, Hendrik J. R.

2018-05-01

We consider operators in N=4 super Yang-Mills theory dual to closed string states propagating on a class of LLM geometries. The LLM geometries we consider are specified by a boundary condition that is a set of black rings on the LLM plane. When projected to the LLM plane, the closed strings are polygons with all corners lying on the outer edge of a single ring. The large N limit of correlators of these operators receives contributions from non-planar diagrams even for the leading large N dynamics. Our interest in these fluctuations is because a previous weak coupling analysis argues that the net effect of summing the huge set of non-planar diagrams, is a simple rescaling of the 't Hooft coupling. We carry out some nontrivial checks of this proposal. Using the su(2|2)2 symmetry we determine the two magnon S-matrix and demonstrate that it agrees, up to two loops, with a weak coupling computation performed in the CFT. We also compute the first finite size corrections to both the magnon and the dyonic magnon by constructing solutions to the Nambu-Goto action that carry finite angular momentum. These finite size computations constitute a strong coupling confirmation of the proposal.

Undermining position effects in choices from arrays, with implications for police lineups.

PubMed

Palmer, Matthew A; Sauer, James D; Holt, Glenys A

2017-03-01

Choices from arrays are often characterized by position effects, such as edge-aversion. We investigated position effects when participants attempted to pick a suspect from an array similar to a police photo lineup. A reanalysis of data from 2 large-scale field studies showed that choices made under realistic conditions-closely matching eyewitness identification decisions in police investigations-displayed edge-aversion and bias to choose from the top row (Study 1). In a series of experiments (Studies 2a-2c and 3), participants guessing the location of a suspect exhibited edge-aversion regardless of whether the lineup was constructed to maximize the chances of the suspect being picked, to ensure the suspect did not stand out, or randomly. Participants favored top locations only when the lineup was constructed to maximize the chances of the suspect being picked. In Studies 4 and 5, position effects disappeared when (a) response options were presented in an array with no obvious center, edges, or corners, and (b) instructions stated that the suspect was placed randomly. These findings show that position effects are influenced by a combination of task instructions and array shape. Randomizing the location of the suspect and modifying the shape of the lineup array may reduce misidentification. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

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.

POWERHOUSES, SOUTH ELEVATIONS SHOWING OIL HOUSE, FILER SUBSTATION, AND DRAFT ...

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

POWERHOUSES, SOUTH ELEVATIONS SHOWING OIL HOUSE, FILER SUBSTATION, AND DRAFT TUBE OUTLET (TAILRACE), VERTICAL VIEW; FACING WEST - Shoshone Falls Hydroelectric Project, Canyon Road, North Bank of Snake River below Shoshone Falls, Tipperary Corner, Jerome County, ID

UNM in the Community.

ERIC Educational Resources Information Center

Quantum: Research & Scholarship, 1998

1998-01-01

Profiles 10 University of New Mexico community programs: University Art Museum, Rio Grande and Four Corners Writing Projects, Blacks in the Southwest (exhibit), New Mexico Engineering Research Institute's Environmental Finance Center, Adolescent Social Action Program, Minority Engineering Programs, Rural Community College Initiative, Valencia…

Fully developed pipe and triangular channel flow measurement using Magnetic Resonance Velocimetry

NASA Astrophysics Data System (ADS)

Baek, Seungchan; Hwang, Wontae

2017-11-01

Magnetic resonance velocimetry (MRV) is a non-intrusive flow visualization method which is able to measure the 3 dimensional 3 component (3D3C) mean velocity field in complex geometries, using a healthcare MRI scanner. Since this technique is based on nuclear magnetic resonance (NMR), it is free from optical distortion and does not require tracer particles. Due to these powerful advantages, MRV usage is gradually expanding from biomedical fields to the engineering domain. In this study, we validate the performance of MRV by measuring fully developed pipe flow and compare measured data with time averaged DNS data. We then investigate the overall flow characteristics in a triangular channel with a sharp corner. At the sharp corner, boundary layer effects dominate and the effect of turbulence is reduced. This information has implications for engineering applications such as flow in a turbine blade internal cooling passage at the sharp trailing edge. This research was supported by the Seoul National University Research Grant in 2017, and Doosan Heavy Industries & Construction. (Contract No. 2016900298 and 2017900095).

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.

A fast RCS accuracy assessment method for passive radar calibrators

NASA Astrophysics Data System (ADS)

Zhou, Yongsheng; Li, Chuanrong; Tang, Lingli; Ma, Lingling; Liu, QI

2016-10-01

In microwave radar radiometric calibration, the corner reflector acts as the standard reference target but its structure is usually deformed during the transportation and installation, or deformed by wind and gravity while permanently installed outdoor, which will decrease the RCS accuracy and therefore the radiometric calibration accuracy. A fast RCS accuracy measurement method based on 3-D measuring instrument and RCS simulation was proposed in this paper for tracking the characteristic variation of the corner reflector. In the first step, RCS simulation algorithm was selected and its simulation accuracy was assessed. In the second step, the 3-D measuring instrument was selected and its measuring accuracy was evaluated. Once the accuracy of the selected RCS simulation algorithm and 3-D measuring instrument was satisfied for the RCS accuracy assessment, the 3-D structure of the corner reflector would be obtained by the 3-D measuring instrument, and then the RCSs of the obtained 3-D structure and corresponding ideal structure would be calculated respectively based on the selected RCS simulation algorithm. The final RCS accuracy was the absolute difference of the two RCS calculation results. The advantage of the proposed method was that it could be applied outdoor easily, avoiding the correlation among the plate edge length error, plate orthogonality error, plate curvature error. The accuracy of this method is higher than the method using distortion equation. In the end of the paper, a measurement example was presented in order to show the performance of the proposed method.

Three-dimensional vibrations of cylindrical elastic solids with V-notches and sharp radial cracks

NASA Astrophysics Data System (ADS)

McGee, O. G.; Kim, J. W.

2010-02-01

This paper provides free vibration data for cylindrical elastic solids, specifically thick circular plates and cylinders with V-notches and sharp radial cracks, for which no extensive previously published database is known to exist. Bending moment and shear force singularities are known to exist at the sharp reentrant corner of a thick V-notched plate under transverse vibratory motion, and three-dimensional (3-D) normal and transverse shear stresses are known to exist at the sharp reentrant terminus edge of a V-notched cylindrical elastic solid under 3-D free vibration. A theoretical analysis is done in this work utilizing a variational Ritz procedure including these essential singularity effects. The procedure incorporates a complete set of admissible algebraic-trigonometric polynomials in conjunction with an admissible set of " edge functions" that explicitly model the 3-D stress singularities which exist along a reentrant terminus edge (i.e., α>180°) of the V-notch. The first set of polynomials guarantees convergence to exact frequencies, as sufficient terms are retained. The second set of edge functions—in addition to representing the corner stress singularities—substantially accelerates the convergence of frequency solutions. This is demonstrated through extensive convergence studies that have been carried out by the investigators. Numerical analysis has been carried out and the results have been given for cylindrical elastic solids with various V-notch angles and depths. The relative depth of the V-notch is defined as (1- c/ a), and the notch angle is defined as (360°- α). For a very small notch angle (1° or less), the notch may be regarded as a "sharp radial crack." Accurate (four significant figure) frequencies are presented for a wide spectrum of notch angles (360°- α), depths (1- c/ a), and thickness ratios ( a/ h for plates and h/ a for cylinders). An extended database of frequencies for completely free thick sectorial, semi-circular, and segmented plates and cylinders are also reported herein as interesting special cases. A generalization of the elasticity-based Ritz analysis and findings applicable here is an arbitrarily shaped V-notched cylindrical solid, being a surface traced out by a family of generatrix, which pass through the circumference of an arbitrarily shaped V-notched directrix curve, r( θ), several of which are described for future investigations and close extensions of this work.

Iron Polymerization and Arsenic Removal During In-Situ Iron Electrocoagulation in Synthetic Bangladeshi Groundwater

NASA Astrophysics Data System (ADS)

van Genuchten, C. M.; Pena, J.; Addy, S.; Gadgil, A.

2010-12-01

Millions of people worldwide are exposed to arsenic-contamination in groundwater drinking supplies. The majority of affected people live in rural Bangladesh. Electrocoagulation (EC) using iron electrodes is a promising arsenic removal strategy that is based on the generation of iron precipitates with a high affinity for arsenic through the electrochemical dissolution of a sacrificial iron anode. Many studies of iron hydrolysis in the presence of co-occurring ions in groundwater such as PO43-, SiO44-, and AsO43- suggest that these ions influence the polymerization and formation of iron oxide phases. However, the combined impact of these ions on precipitates generated by EC is not well understood. X-ray absorption spectroscopy (XAS) was used to examine EC precipitates generated in synthetic Bangladeshi groundwater (SBGW). The iron oxide structure and arsenic binding geometry were investigated as a function of EC operating conditions. As and Fe k-edge spectra were similar between samples regardless of the large range of current density (0.02, 1.1, 5.0, 100 mA/cm2) used during sample generation. This result suggests that current density does not play a large role in the formation EC precipitates in SBGW. Shell-by-shell fits of Fe K-edge data revealed the presence of a single Fe-Fe interatomic distance at approximately 3.06 Å. The absence of longer ranged Fe-Fe correlations suggests that EC precipitates consist of nano-scale chains (polymers) of FeO6 octahedra sharing equatorial edges. Shell-by-shell fits of As K-edge spectra show arsenic bound in primarily bidentate, binuclear corner sharing complexes. In this coordination geometry, arsenic prevents the formation of FeO6 corner-sharing linkages, which are necessary for 3-dimensional crystal growth. The individual and combined effects of other anions, such as PO43- and SiO44- present in SBGW are currently being investigated to determine the role of these ions in stunting crystal growth. The results provided by this study are useful in explaining the large adsorption capacity of EC precipitates. This study will also lead to better predictions of arsenic removal efficiency during EC and a better understanding of the long-term stability of arsenic-laden EC sludge.

Map Projection Induced Variations in Locations of Polygon Geofence Edges

NASA Technical Reports Server (NTRS)

Neeley, Paula; Narkawicz, Anthony

2017-01-01

This Paper under-estimates answers to the following question under various constraints: If a geofencing algorithm uses a map projection to determine whether a position is inside/outside a polygon region, how far outside/inside the polygon can the point be and the algorithm determine that it is inside/outside (the opposite and therefore incorrect answer)? Geofencing systems for unmanned aircraft systems (UAS) often model stay-in and stay-out regions using 2D polygons with minimum and maximum altitudes. The vertices of the polygons are typically input as latitude-longitude pairs, and the edges as paths between adjacent vertices. There are numerous ways to generate these paths, resulting in numerous potential locations for the edges of stay-in and stay-out regions. These paths may be geodesics on a spherical model of the earth or geodesics on the WGS84 reference ellipsoid. In geofencing applications that use map projections, these paths are inverse images of straight lines in the projected plane. This projected plane may be a projection of a spherical earth model onto a tangent plane, called an orthographic projection. Alternatively, it may be a projection where the straight lines in the projected plane correspond to straight lines in the latitudelongitude coordinate system, also called a Plate Carr´ee projection. This paper estimates distances between different edge paths and an oracle path, which is a geodesic on either the spherical earth or the WGS84 ellipsoidal earth. This paper therefore estimates how far apart different edge paths can be rather than comparing their path lengths, which are not considered. Rather, the comparision is between the actual locations of the edges between vertices. For edges drawn using orthographic projections, this maximum distance increases as the distance from the polygon vertices to the projection point increases. For edges drawn using Plate Carr´ee projections, this maximum distance increases as the vertices become further from the equator. Distances between geodesics on a spherical earth and a WGS84 ellipsoidal earth are also analyzed, using the WGS84 ellipsoid as the oracle. Bounds on the 2D distance between a straight line and a great circle path, in an orthographically projected plane rather than on the surface of the earth, have been formally verified in the PVS theorem prover, meaning that they are mathematically correct in the absence of floating point errors.

Experimental investigation of starting characteristics and wave propagation from a shallow open cavity and its acoustic emission at supersonic speed

NASA Astrophysics Data System (ADS)

Pandian, S.; Desikan, S. L. N.; Niranjan, Sahoo

2018-01-01

Experiments were carried out on a shallow open cavity (L/D = 5) at a supersonic Mach number (M = 1.8) to understand its transient starting characteristics, wave propagation (inside and outside the cavity) during one vortex shedding cycle, and acoustic emission. Starting characteristics and wave propagation were visualized through time resolved schlieren images, while acoustic emissions were captured through unsteady pressure measurements. Results showed a complex shock system during the starting process which includes characteristics of the bifurcated shock system, shock train, flow separation, and shock wave boundary layer interaction. In one vortex shedding cycle, vortex convection from cavity leading edge to cavity trailing edge was observed. Flow features outside the cavity demonstrated the formation and downstream movement of a λ-shock due to the interaction of shock from the cavity leading edge and shock due to vortex and generation of waves on account of shear layer impingement at the cavity trailing edge. On the other hand, interesting wave structures and its propagation were monitored inside the cavity. In one vortex shedding cycle, two waves such as a reflected compression wave from a cavity leading edge in the previous vortex shedding cycle and a compression wave due to the reflection of Mach wave at the cavity trailing edge corner in the current vortex shedding cycle were visualized. The acoustic emission from the cavity indicated that the 2nd to 4th modes/tones are dominant, whereas the 1st mode contains broadband spectrum. In the present studies, the cavity feedback mechanism was demonstrated through a derived parameter coherence coefficient.

Modeling and measurement of a micro-optic beam deflector

NASA Technical Reports Server (NTRS)

Milster, Tom D.; Wong, J. Nan

1992-01-01

The use is studied of a unity-magnification micro-optic beam deflector. The defelector consists of two arrays of positively powered lenslets. The lenslets on each array are arranged in a square grid. Design criteria are based on usefulness in optical data storage devices. The deflector is designed to operate over a + or - 1.6 range of deflection angles. Modeling results are compared with interferometric analysis of the wavefront from a single lenslet pair. The results indicate that the device is nearly diffraction limited, but there are substantial wavefront errors at the edges and corners of the lenslets.

Multiple feature extraction by using simultaneous wavelet transforms

NASA Astrophysics Data System (ADS)

Mazzaferri, Javier; Ledesma, Silvia; Iemmi, Claudio

2003-07-01

We propose here a method to optically perform multiple feature extraction by using wavelet transforms. The method is based on obtaining the optical correlation by means of a Vander Lugt architecture, where the scene and the filter are displayed on spatial light modulators (SLMs). Multiple phase filters containing the information about the features that we are interested in extracting are designed and then displayed on an SLM working in phase mostly mode. We have designed filters to simultaneously detect edges and corners or different characteristic frequencies contained in the input scene. Simulated and experimental results are shown.

Thin-layer approximation and algebraic model for separated turbulent flows

NASA Technical Reports Server (NTRS)

Baldwin, B.; Lomax, H.

1978-01-01

An algebraic turbulence model for two- and three-dimensional separated flows is specified that avoids the necessity for finding the edge of the boundary layer. Properties of the model are determined and comparisons made with experiment for an incident shock on a flat plate, separated flow over a compression corner, and transonic flow over an airfoil. Separation and reattachment points from numerical Navier-Stokes solutions agree with experiment within one boundary-layer thickness. Use of law-of-the-wall boundary conditions does not alter the predictions significantly. Applications of the model to other cases are contained in companion papers.

d +i d chiral superconductivity in a triangular lattice from trigonal bipyramidal complexes

NASA Astrophysics Data System (ADS)

Lu, Chen; Zhang, Li-Da; Wu, Xianxin; Yang, Fan; Hu, Jiangping

2018-04-01

We model the newly predicted high-Tc superconducting candidates constructed by corner-shared trigonal bipyramidal complexes with an effective three-orbital tight-binding Hamiltonian and investigate the pairing symmetry of their superconducting states driven by electron-electron interactions. Our combined weak- and strong-coupling-based calculations consistently identify the chiral d +i d superconductivity as the leading pairing symmetry in a wide doping range with realistic interaction parameters. This pairing state has a nontrivial topological Chern number and can host gapless chiral edge modes, and the vortex cores under magnetic field can carry Majorana zero modes.

Air flow testing on aerodynamic truck

NASA Technical Reports Server (NTRS)

1975-01-01

After leasing a cab-over tractor-trailer from a Southern California firm, Dryden researchers added sheet metal modifications like those shown here. They rounded the front corners and edges, and placed a smooth fairing on the cab's roofs and sides extending back to the trailer. During the investigation of truck aerodynamics, the techniques honed in flight research proved highly applicable. By closing the gap between the cab and the trailer, for example, researchers discovered a significant reduction in aerodynamic drag, one resulting in 20 to 25 percent less fuel consumption than the standard design. Many truck manufacturers subsequently incorporated similar modifications on their products.

Evaluation Transportability Testing of the Joint Modular Intermodal Platform (JMIP) Unit #4 TP-94-01, Revision 2, June 2004, Transportability Testing Procedures

DTIC Science & Technology

2007-07-01

Weight: 19,340 lbs 3-1 5. Semitrailer, flatbed , breakbulk/container transporter, 34 ton Model #: M872A1 Manufactured by Heller Truck Body Corporation...REQD). LAMINATE TO BEARING PIECE W/6-10d NAILS EVENLY SPACED. SIDE STRAPPING BOARD ASSEMBLY (4 RECD) EPAGE 5 NOTE: PRODUCE EQUAL QUANTITES OF ASSEMBLY...A AND ASSEMBLY B. EACH JMIP LOAD REQUIRES iWO OF EACH (4 TOTAL). STEEL EDGE PROTECTORS (2 REQD). LAMINATE TO BEARING AND CORNER PIECES W/4-6d NALS AND

Gas Dynamic Spray Technology Demonstration

NASA Technical Reports Server (NTRS)

Burford, Pattie Lewis

2011-01-01

Zinc primer systems are currently used across NASA and AFSPC for corrosion protection of steel. AFSPC and NASA have approved the use of Thermal Spray Coatings (TSCs) as an environmentally preferable alternative. TSCs are approved in NASA-STD-5008 and AFSPC and KSC is currently looking for additional applications in which TSC can be used. Gas Dynamic Spray (GDS, also known as Cold Spray) is being evaluated as a means of repairing TSCs and for areas such as corners and edges where TSCs do not work as well. Other applications could include spot repair/maintenance of steel on structures, facilities, and ground support equipment.

Numerical analysis of the impact of permeability on trailing-edge noise

NASA Astrophysics Data System (ADS)

Koh, Seong Ryong; Meinke, Matthias; Schröder, Wolfgang

2018-05-01

The impact of porous surfaces on the near-wall turbulent structures and the generated trailing-edge noise is analyzed for several trailing-edge shapes of finite thickness using a high resolution large-eddy simulation (LES)/computational aeroacoustics (CAA) method. The porous surface of the trailing edge is defined by the porosity and the viscous permeability determined by the solution of a turbulent flat plate boundary layer at a Reynolds number 1280 based on the displacement thickness in the inflow cross section. The volume-averaged approach for the homogeneous porous medium shows that the porous impedance scales linearly with the porosity and exponentially with the mean structure size of a porous medium. The drag induced by the porous surface changes the friction velocity and the permeability Reynolds number ReK which determines the porous impedance Rs scaled by ReK-2/3. The trailing-edge noise is analyzed for three solid and three porous trailing edges. The effect of a finite span is investigated by the spanwise correlation model based on the measured coherence distribution. The acoustic prediction shows a good agreement with measurements of the broadband spectrum and the strong tone generated by a finite trailing-edge thickness. The pressure gradient inside the porous media is redistributed by the Darcy drag defined by the viscous permeability and the porosity. The mean pressure increases in the upstream direction inside the porous medium such that the flow acceleration involved in the acoustic generation is reduced inside the porous medium. The noise reduction by a porous medium reaches 11 dB for the trailing-edge shape which possesses a sharp corner for the solid surface. The porous surface applied to a semi-circular trailing edge achieves a 4 dB noise reduction. The directivity pattern for individual components of the acoustic spectrum shows that the massive noise reduction is determined at the tone. Enhanced wave diffraction by the thick flat plate changes the directivity pattern in the high frequency range.

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.

Arthroscopic Anatomy of the Ankle Joint.

PubMed

Ray, Ronald G

2016-10-01

There are a number of variations in the intra-articular anatomy of the ankle which should not be considered pathological under all circumstances. The anteromedial corner of the tibial plafond (between the anterior edge of the tibial plafond and the medial malleolus) can have a notch, void of cartilage and bone. This area can appear degenerative arthroscopically; it is actually a normal variant of the articular surface. The anterior inferior tibiofibular ligament (AITF) can possess a lower, accessory band which can impinge on the anterolateral edge of the talar dome. In some cases it can cause irritation along this area of the talus laterally. If it is creating local irritation it can be removed since it does not provide any additional stabilization to the syndesmosis. There is a beveled region at the anterior leading edge of the lateral and dorsal surfaces of the talus laterally. This triangular region is void of cartilage and subchondral bone. The lack of talar structure in this region allows the lower portion of the AITF ligament to move over the talus during end range dorsiflexion of the ankle, preventing impingement. The variation in talar anatomy for this area should not be considered pathological. Copyright © 2016 Elsevier Inc. All rights reserved.

38 CFR 39.32 - Plan preparation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... a previously approved project and there have been no changes. Relevant information may then be shown... having other change or direction between corners) shall be referenced with curve data (including... indicated. The master plan shall analyze all factors affecting the design, including climate, soil...

AFRC2016-0082-13

NASA Image and Video Library

2016-03-10

NASA photographer Jim Ross captured this shot while pilot Troy Asher flew inverted in an F-15D. The F-15B is seen here flying over the mirror farm, AKA the Abengoa Mojave Solar Project, east of Four Corners off of Highway 58 in Southern California.

38 CFR 39.8 - Plan preparation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... previously approved project and there have been no changes. Relevant information may then be shown on the.... Boundaries of an unusual nature (curvilinear, off-set, or having other change or direction between corners..., including climate, soil conditions, site boundaries, topography, views, hydrology, environmental constraints...

A DUAL APPROACH TO MODELING CORNER SOLUTIONS IN RECREATION DEMAND. (R826615)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

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.

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.

REMEDIATION TECHNOLOGY EVALUATION AT THE GILT EDGE MINE, SOUTH DAKOTA

EPA Science Inventory

This document reports the findings of the Mine Waste Technology Program's Activity III, Project 29,The Remediation Technology Evaluation Project at the Gilt Edge Mine, S.D. This project consisted of evaluating three emerging acidic waste rock stabilization technologies and compar...

Entrepreneurship Competencies.

ERIC Educational Resources Information Center

Cataldo, Paul F.

Enterprise Skills Development Project for Youth (ESDPY), renamed Project EDGE (Encouraging the Development and Growth of Entrepreneurship), is described in this report. Project EDGE is a training program that assists youth in acquiring the entrepreneurial and life skills necessary to become successful employees/employers in the information age.…

Flight and full-scale wind-tunnel comparison of pressure distributions from an F-18 aircraft at high angles of attack. [Conducted in NASA Ames Research Center's 80 by 120 ft wind tunnel

NASA Technical Reports Server (NTRS)

Fisher, David F.; Lanser, Wendy R.

1994-01-01

Pressure distributions were obtained at nearly identical fuselage stations and wing chord butt lines in flight on the F-18 HARV at NASA Dryden Flight Research Center and in the NASA Ames Research Center's 80 by 120 ft wind tunnel on a full-scale F/A-18 aircraft. The static pressures were measured at the identical five stations on the forebody, three stations on the left and right leading-edge extensions, and three spanwise stations on the wing. Comparisons of the flight and wind-tunnel pressure distributions were made at alpha = 30 deg, 45 deg, and 60 deg/59 deg. In general, very good agreement was found. Minor differences were noted at the forebody at alpha = 45 deg and 60 deg in the magnitude of the vortex footprints and a Mach number effect was noted at the leading-edge extension at alpha = 30 deg. The inboard leading edge flap data from the wind tunnel at alpha = 59 deg showed a suction peak that did not appear in the flight data. This was the result of a vortex from the corner of the leading edge flap whose path was altered by the lack of an engine simulation in the wind tunnel.

Vertical view of Arab Republic of Egypt from ASTP mission

NASA Image and Video Library

1975-07-19

AST-09-555 (19 July 1975) --- A vertical view of a portion of the Arab Republic of Egypt, as photographed from the Apollo spacecraft in Earth orbit during the joint U.S.-USSR Apollo-Soyuz Test Project mission. The Nile Delta is in the most northerly corner of the picture. The City of Cairo on the Nile River is in the center of the photograph. The Gulf of Suez is in the most easterly corner of the picture. El Faiyum is south-southwest of Cairo. This picture was taken at an altitude of 223 kilometers (138 statute miles), with a 70mm Hasselblad camera using medium-speed Ektachrome QX-807 type film.

Mechanical properties of Fe rich Fe-Si alloys: ab initio local bulk-modulus viewpoint

NASA Astrophysics Data System (ADS)

Bhattacharya, Somesh Kr; Kohyama, Masanori; Tanaka, Shingo; Shiihara, Yoshinori; Saengdeejing, Arkapol; Chen, Ying; Mohri, Tetsuo

2017-11-01

Fe-rich Fe-Si alloys show peculiar bulk-modulus changes depending on the Si concentration in the range of 0-15 at.%Si. In order to clarify the origin of this phenomenon, we have performed density-functional theory calculations of supercells of Fe-Si alloy models with various Si concentrations. We have applied our recent techniques of ab initio local energy and local stress, by which we can obtain a local bulk modulus of each atom or atomic group as a local constituent of the cell-averaged bulk modulus. A2-phase alloy models are constructed by introducing Si substitution into bcc Fe as uniformly as possible so as to prevent mutual neighboring, while higher Si concentrations over 6.25 at.%Si lead to contacts between SiFe8 cubic clusters via sharing corner Fe atoms. For 12.5 at.%Si, in addition to an A2 model, we deal with partial D03 models containing local D03-like layers consisting of edge-shared SiFe8 cubic clusters. For the cell-averaged bulk modulus, we have successfully reproduced the Si-concentration dependence as a monotonic decrease until 11.11 at.%Si and a recovery at 12.5 at.%Si. The analysis of local bulk moduli of SiFe8 cubic clusters and Fe regions is effective to understand the variations of the cell-averaged bulk modulus. The local bulk moduli of Fe regions become lower for increasing Si concentration, due to the suppression of bulk-like d-d bonding states in narrow Fe regions. For higher Si concentrations till 11.11 at.%Si, corner-shared contacts or 1D chains of SiFe8 clusters lead to remarkable reduction of local bulk moduli of the clusters. At 12 at.%Si, on the other hand, two- or three-dimensional arrangements of corner- or edge-shared SiFe8 cubic clusters show greatly enhanced local bulk moduli, due to quite different bonding nature with much stronger p-d hybridization. The relation among the local bulk moduli, local electronic and magnetic structures, and local configurations such as connectivity of SiFe8 clusters and Fe-region sizes has been analyzed. The ab initio local stress has opened the way for obtaining accurate local elastic properties reflecting local valence-electron behaviors.

High pressure synthesis and properties of ternary titanium (III) fluorides in the system KF-TiF 3 containing regular pentagonal bipyramids [TiF 7

NASA Astrophysics Data System (ADS)

Yamanaka, Shoji; Yasuda, Akira; Miyata, Hajime

2010-01-01

Titanium trifluoride TiF 3 has the distorted ReO 3 structure composed of corner sharing TiF 6 octahedra linked with Ti-F-Ti bridges. Potassium fluoride KF was inserted into the bridges using high-pressure and high-temperature conditions (5 GPa, 1000-1200 °C). When the molar ratio KF/TiF 3≥1, a few low dimensional compounds were obtained forming non-bridged F ions. At the composition KF/TiF 3=1/2, a new compound KTi 2F 7 was formed, which crystallizes with the space group Cmmm and the lattice parameters of a=6.371(3), b=10.448(6), c=3.958(2) Å, consisting of edge-sharing pentagonal bipyramids [TiF 7] forming ribbons running along the a axis. The ribbons are linked by corners to construct a three-dimensional framework without forming non-bridged F ions. The compound is antiferromagnetic with the Néel temperature T N=75 K, and the optical band gap was 6.4 eV. A new fluoride K 2TiF 5 (KF/TiF 3=2) with the space group Pbcn and the lattice parameters of a=7.4626(2), b=12.9544(4) and c=20.6906(7) Å was also obtained by the high pressure and high temperature treatment (5 GPa at 1000 °C) of a molar mixture of 2 KF+TiF 3. The compound contains one-dimensional chains of corner-sharing TiF 6 octahedra.

The new high-pressure borate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O-Formation of edge-sharing BO{sub 4} tetrahedra in a hydrated borate

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

Neumair, Stephanie C.; Kaindl, Reinhard; Huppertz, Hubert, E-mail: hubert.huppertz@uibk.ac.at

2012-01-15

The new borate hydrate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O was synthesized under high-pressure/high-temperature conditions of 6 GPa and 880 Degree-Sign C in a Walker-type multianvil apparatus. The compound crystallizes in the orthorhombic space group Pbam (Z=2) with the lattice parameters a=819.0(2), b=2016.9(4), c=769.9(2) pm, V=1.2717(4) nm{sup 3}, R{sub 1}=0.0758, wR{sub 2}=0.0836 (all data). The new structure type of Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O is built up from corner-sharing BO{sub 4} tetrahedra forming corrugated layers, that are interconnected among each other by two edge-sharing BO{sub 4} tetrahedra (B{sub 2}O{sub 6} units) forming Z-shaped channels. Interestingly, the heremore » presented structure of Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O is closely related to the structures of M{sub 6}B{sub 22}O{sub 39}{center_dot}H{sub 2}O (M=Fe, Co), which exhibit BO{sub 4} tetrahedra in an intermediate state on the way to edge-sharing BO{sub 4} tetrahedra. - Graphical Abstract: The new high-pressure borate hydrate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O is built up from corner-sharing BO{sub 4} tetrahedra forming corrugated layers, that are interconnected among each other by two edge-sharing BO{sub 4} tetrahedra (B{sub 2}O{sub 6} units). In this paper we report on synthesis, structural details, and properties of the new compound Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O. Highlights: Black-Right-Pointing-Pointer High-pressure/high-temperature synthesis of the new borate hydrate Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O. Black-Right-Pointing-Pointer In the structure of Co{sub 7}B{sub 24}O{sub 42}(OH){sub 2}{center_dot}2 H{sub 2}O, two B{sub 2}O{sub 6} units are connected to 'vierer' rings. Black-Right-Pointing-Pointer Pressure favours the formation of edge-sharing BO{sub 4} tetrahedra in the chemistry of borates.« less

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.

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.

ARC-1989-A89-7004

NASA Image and Video Library

1989-08-19

Range : 8.6 million kilometers (5.3 million miles) The Voyager took this 61 second exposure through the clear filter with the narrow angle camera of Neptune. The Voyager cameras were programmed to make a systematic search for faint ring arcs and new satellites. The bright upper corner of the image is due to a residual image from a previous long exposure of the planet. The portion of the arc visible here is approximately 35 degrees in longitudinal extent, making it approximately 38,000 kilometers (24,000 miles) in length, and is broken up into three segments separated from each other by approximately 5 degrees. The trailing edge is at the upper right and has an abrupt end while the leading edge seems to fade into the background more gradually. This arc orbits very close to one of the newly discovered Neptune satellites, 1989N4. Close-up studies of this ring arc will be carried out in the coming days which will give higher spatial resolution at different lighting angles. (JPL Ref: P-34617)

11. photographer unknown 3 September 1984 AERIAL VIEW OF BONNEVILLE ...

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

11. photographer unknown 3 September 1984 AERIAL VIEW OF BONNEVILLE PROJECT TAKEN AT 6000-FOOT ELEVATION. POWERHOUSE #1 AND NAVIGATION LOCK ARE IN UPPER/CENTER PART OF PHOTO, AND THE DAM/SPILLWAY IS IN LEFT/CENTER; THE SECOND POWERHOUSE IS PARTIALLY VISIBLE IN LOWER LEFT CORNER. COLUMBIA RIVER FLOWS FROM LEFT-TO-RIGHT. - Bonneville Project, Columbia River, 1 mile Northeast of Exit 40, off Interstate 84, Bonneville, Multnomah County, OR

VALUING WATER QUALITY IMPROVEMENTS USING REVEALED PREFERENCE METHODS WHEN CORNER SOLUTIONS ARE PRESENT. (R826615)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

13. DETAIL VIEW, OF TAINTER GATE PIER, SHOWING RECESSES FOR ...

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

13. DETAIL VIEW, OF TAINTER GATE PIER, SHOWING RECESSES FOR EMERGENCY BULKHEADS AND DOGGING DEVICES, LOOKING SOUTHEAST (DOWN FACE). UPSTREAM FACE OF TAINTER GATE IS VISIBLE IN UPPER RIGHT CORNER - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 26R, Alton, Madison County, IL

Pinwheel Prints.

ERIC Educational Resources Information Center

Derby, Marie

1998-01-01

Presents a printmaking project that enables students to work with lines and shapes by having them create tile designs on Scratch-Foam Board. Explains that the shape of the combined four tiles should be a pinwheel while the design on one corner of each tile should connect forming a design within itself. (CMK)

Chemically attached gold nanoparticle-carbon nanotube hybrids for highly sensitive SERS substrate

NASA Astrophysics Data System (ADS)

Beqa, Lule; Singh, Anant Kumar; Fan, Zheng; Senapati, Dulal; Ray, Paresh Chandra

2011-08-01

Surface-enhanced Raman spectroscopy (SERS) has been shown as one of the most powerful analytical tool with high sensitivity. In this manuscript, we report the chemical design of SERS substrate, based on gold nanoparticles of different shapes-decorated with carbon nanotube with an enhancement factor of 7.5 × 1010. Shape dependent result shows that popcorn shape gold nanoparticle decorated SWCNT is the best choice for SERS substrate due to the existence of 'lightning rod effect' through several sharp edges or corners. Our results provide a good approach to develop highly sensitive SERS substrates and can help to improve the fundamental understanding of SERS phenomena.

Composite materials: Fatigue and fracture. Vol. 3

NASA Technical Reports Server (NTRS)

O'Brien, T. K. (Editor)

1991-01-01

The present volume discusses topics in the fields of matrix cracking and delamination, interlaminar fracture toughness, delamination analysis, strength and impact characteristics, and fatigue and fracture behavior. Attention is given to cooling rate effects in carbon-reinforced PEEK, the effect of porosity on flange-web corner strength, mode II delamination in toughened composites, the combined effect of matrix cracking and free edge delamination, and a 3D stress analysis of plain weave composites. Also discussed are the compression behavior of composites, damage-based notched-strength modeling, fatigue failure processes in aligned carbon-epoxy laminates, and the thermomechanical fatigue of a quasi-isotropic metal-matrix composite.

A topological coordinate system for the diamond cubic grid.

PubMed

Čomić, Lidija; Nagy, Benedek

2016-09-01

Topological coordinate systems are used to address all cells of abstract cell complexes. In this paper, a topological coordinate system for cells in the diamond cubic grid is presented and some of its properties are detailed. Four dependent coordinates are used to address the voxels (triakis truncated tetrahedra), their faces (hexagons and triangles), their edges and the points at their corners. Boundary and co-boundary relations, as well as adjacency relations between the cells, can easily be captured by the coordinate values. Thus, this coordinate system is apt for implementation in various applications, such as visualizations, morphological and topological operations and shape analysis.

KMg0.09Fe1.91(PO4)2

PubMed Central

Yatskin, Michael M.; Zatovsky, Igor V.; Baumer, Vyacheslav N.; Ogorodnyk, Ivan V.; Slobodyanik, Nikolay S.

2012-01-01

KMg0.09Fe1.91(PO4)2, potassium [iron(II)/magnesium] iron(III) bis(orthophosphate), is a solid solution derived from compounds with general formula KM IIFe(PO4)2 (M II = Fe, Cu), in which the Mg atoms substitute Fe atoms only in the octa­hedrally surrounded sites. The framework of the structure is built up from [FeO5] trigonal bipyramids and [MO6] (M = (Fe, Mg) octa­hedra sharing corners and edges and connected by two types of bridging PO4 tetra­hedra. The K+ cations are nine-coordinated and are situated in channels running along [101]. PMID:22719280

Pyramidal space frame and associated methods

DOEpatents

Clark, Ryan Michael; White, David; Farr, Jr, Adrian Lawrence

2016-07-19

A space frame having a high torsional strength comprising a first square bipyramid and two planar structures extending outward from an apex of the first square bipyramid to form a "V" shape is disclosed. Some embodiments comprise a plurality of edge-sharing square bipyramids configured linearly, where the two planar structures contact apexes of all the square bipyramids. A plurality of bridging struts, apex struts, corner struts and optional internal bracing struts increase the strength and rigidity of the space frame. In an embodiment, the space frame supports a solar reflector, such as a parabolic solar reflector. Methods of fabricating and using the space frames are also disclosed.

Low dose CBCT reconstruction via prior contour based total variation (PCTV) regularization: a feasibility study

NASA Astrophysics Data System (ADS)

Chen, Yingxuan; Yin, Fang-Fang; Zhang, Yawei; Zhang, You; Ren, Lei

2018-04-01

Purpose: compressed sensing reconstruction using total variation (TV) tends to over-smooth the edge information by uniformly penalizing the image gradient. The goal of this study is to develop a novel prior contour based TV (PCTV) method to enhance the edge information in compressed sensing reconstruction for CBCT. Methods: the edge information is extracted from prior planning-CT via edge detection. Prior CT is first registered with on-board CBCT reconstructed with TV method through rigid or deformable registration. The edge contours in prior-CT is then mapped to CBCT and used as the weight map for TV regularization to enhance edge information in CBCT reconstruction. The PCTV method was evaluated using extended-cardiac-torso (XCAT) phantom, physical CatPhan phantom and brain patient data. Results were compared with both TV and edge preserving TV (EPTV) methods which are commonly used for limited projection CBCT reconstruction. Relative error was used to calculate pixel value difference and edge cross correlation was defined as the similarity of edge information between reconstructed images and ground truth in the quantitative evaluation. Results: compared to TV and EPTV, PCTV enhanced the edge information of bone, lung vessels and tumor in XCAT reconstruction and complex bony structures in brain patient CBCT. In XCAT study using 45 half-fan CBCT projections, compared with ground truth, relative errors were 1.5%, 0.7% and 0.3% and edge cross correlations were 0.66, 0.72 and 0.78 for TV, EPTV and PCTV, respectively. PCTV is more robust to the projection number reduction. Edge enhancement was reduced slightly with noisy projections but PCTV was still superior to other methods. PCTV can maintain resolution while reducing the noise in the low mAs CatPhan reconstruction. Low contrast edges were preserved better with PCTV compared with TV and EPTV. Conclusion: PCTV preserved edge information as well as reduced streak artifacts and noise in low dose CBCT reconstruction. PCTV is superior to TV and EPTV methods in edge enhancement, which can potentially improve the localization accuracy in radiation therapy.

Nilosyrtis Mensae

NASA Technical Reports Server (NTRS)

1997-01-01

A color image of part of the Nilosyrtis Mensae region of Mars containing the impact craters Antoniadi and Baldet (south to north) in the lower left corner; north toward top. The scene shows heavily cratered highlands on the south separated from the relatively smooth lowland plains on the northeast corner by a belt of dissected terrain, containing flat-floored valleys, mesas, buttes, and channels. The channels are (left to right) Auqakuh and Huo Hsing Valles; Nili Fossae lie in lower right corner of image.

This image is a composite of Viking medium-resolution images in black and white and low-resolution images in color. The image extends from latitude 20 degrees N. to 40 degrees N. and from longitude 280 degrees to 305 degrees. Mercator projection is used below 30 degrees N.; Lambert projection is used above 30 degrees N.

The dissected terrain along the highlands/lowlands boundary consist of the flat-floored valleys (mensae) and farther north the small, rounded hills of knobby terrain. Flows on the mensa floors contain striae that run parallel to valley walls; where valleys meet, the striae merge, similar to medial moraines on glaciers. Terraces within the valley hills have been interpreted as either layer rocks or wave terraces. The knobby terrain has been interpreted as remnants of the old, densely cratered highland terrain perhaps eroded by mass wasting. Auqakuh and Huo Hsing Valles and Nili Fossae are fretted channels and linear depressions that likely formed by sapping and mass wasting along lines of structural weakness.

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.

Synthesis, crystal structure, and vibrational study of K2Cu(HPO4)2·6H2O: A new metal hydrogenphosphate compound

NASA Astrophysics Data System (ADS)

Ettoumi, Houda; Bulou, Alain; Suñol, Joan Josep; Mhiri, Tahar

2015-11-01

The study reports on the synthesis, single-crystal X-ray structure, and infrared and polarized Raman spectra of a new metal phosphate. The chemical formula of the compound K2Cu(HPO4)2·6H2O resembled that of Tutton salts. The compound crystallized in the monoclinic system, space group P21/c, with a = 6.166(9), b = 12.118(19), c = 9.077(14) Å, β = 104.33(2), and Z = 2. The compound consisted of transition metal cations octahedrally coordinated by six water molecules, [Cu(H2O)6]2+, HPO4 pseudo-tetrahedra, and KO8 polyhedra. The KO8 polyhedra shared two edges with two HPO4 groups, two corners with the two other HPO4 groups, and two corners with Cu(H2O)6. The connection between [Cu(H2O)6]2+ octahedral and (HPO4)2- pseudo-tetrahedra was reinforced by hydrogen bonds formed between the water molecules and other oxygen atoms linked to the P atom. These structural results were corroborated by infrared and polarized Raman spectroscopy.

Wind tunnel tests for wind pressure distribution on gable roof buildings.

PubMed

Jing, Xiao-kun; Li, Yuan-qi

2013-01-01

Gable roof buildings are widely used in industrial buildings. Based on wind tunnel tests with rigid models, wind pressure distributions on gable roof buildings with different aspect ratios were measured simultaneously. Some characteristics of the measured wind pressure field on the surfaces of the models were analyzed, including mean wind pressure, fluctuating wind pressure, peak negative wind pressure, and characteristics of proper orthogonal decomposition results of the measured wind pressure field. The results show that extremely high local suctions often occur in the leading edges of longitudinal wall and windward roof, roof corner, and roof ridge which are the severe damaged locations under strong wind. The aspect ratio of building has a certain effect on the mean wind pressure coefficients, and the effect relates to wind attack angle. Compared with experimental results, the region division of roof corner and roof ridge from AIJ2004 is more reasonable than those from CECS102:2002 and MBMA2006.The contributions of the first several eigenvectors to the overall wind pressure distributions become much bigger. The investigation can offer some basic understanding for estimating wind load distribution on gable roof buildings and facilitate wind-resistant design of cladding components and their connections considering wind load path.

Stage Cylindrical Immersive Display

NASA Technical Reports Server (NTRS)

Abramyan, Lucy; Norris, Jeffrey S.; Powell, Mark W.; Mittman, David S.; Shams, Khawaja S.

2011-01-01

Panoramic images with a wide field of view intend to provide a better understanding of an environment by placing objects of the environment on one seamless image. However, understanding the sizes and relative positions of the objects in a panorama is not intuitive and prone to errors because the field of view is unnatural to human perception. Scientists are often faced with the difficult task of interpreting the sizes and relative positions of objects in an environment when viewing an image of the environment on computer monitors or prints. A panorama can display an object that appears to be to the right of the viewer when it is, in fact, behind the viewer. This misinterpretation can be very costly, especially when the environment is remote and/or only accessible by unmanned vehicles. A 270 cylindrical display has been developed that surrounds the viewer with carefully calibrated panoramic imagery that correctly engages their natural kinesthetic senses and provides a more accurate awareness of the environment. The cylindrical immersive display offers a more natural window to the environment than a standard cubic CAVE (Cave Automatic Virtual Environment), and the geometry allows multiple collocated users to simultaneously view data and share important decision-making tasks. A CAVE is an immersive virtual reality environment that allows one or more users to absorb themselves in a virtual environment. A common CAVE setup is a room-sized cube where the cube sides act as projection planes. By nature, all cubic CAVEs face a problem with edge matching at edges and corners of the display. Modern immersive displays have found ways to minimize seams by creating very tight edges, and rely on the user to ignore the seam. One significant deficiency of flat-walled CAVEs is that the sense of orientation and perspective within the scene is broken across adjacent walls. On any single wall, parallel lines properly converge at their vanishing point as they should, and the sense of perspective within the scene contained on only one wall has integrity. Unfortunately, parallel lines that lie on adjacent walls do not necessarily remain parallel. This results in inaccuracies in the scene that can distract the viewer and subtract from the immersive experience of the CAVE.

Engaging Students in Learning: An Application with Quantitative Psychology

ERIC Educational Resources Information Center

Harlow, Lisa L.; Burkholder, Gary J.; Morrow, Jennifer A.

2006-01-01

In response to calls for more engaging and interactive pedagogy, we simultaneously implemented 4 rousing learning activities: peer-mentored learning, student reports of what was clear (or not) from a previous lecture, consult corners where student groups provided course-informed solutions to problem-based scenarios, and applied projects presented…

ESTIMATION AND WELFARE CALCULATIONS IN A GENERALIZED CORNER SOLUTION MODEL WITH AN APPLICATION TO RECREATION DEMAND. (R826615)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Window type: paired 3x2 multipaned steel window flanked by 1x3 ...

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

Window type: paired 3x2 multipaned steel window flanked by 1x3 multipaned steel casements, breaking building corner. Broad overhanging eave also illustrated. Second story detail. Building 13, facing east - Harbor Hills Housing Project, 26607 Western Avenue, Lomita, Los Angeles County, CA

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.

Reduced heat input keyhole welding through improved joint design

NASA Technical Reports Server (NTRS)

Sanders, John M. (Inventor); Harwig, Dennis D. (Inventor)

1993-01-01

An improved high energy density welding method for reducing input keyhole welding prepares the weld joint (8) between two edges (10, 14) of at least one member by separating the edges (10, 14) of the member (12, 16) with a controllable gap (22) by a projecting portion (24) selectively positioned on one edge (10, 14) of the member (12, 16). The projecting portion (24) closely abuts the other edge of the member for maintaining the controlled distance (d) of the controllable gap (22) to enhance the welding method.

Context dependent anti-aliasing image reconstruction

NASA Technical Reports Server (NTRS)

Beaudet, Paul R.; Hunt, A.; Arlia, N.

1989-01-01

Image Reconstruction has been mostly confined to context free linear processes; the traditional continuum interpretation of digital array data uses a linear interpolator with or without an enhancement filter. Here, anti-aliasing context dependent interpretation techniques are investigated for image reconstruction. Pattern classification is applied to each neighborhood to assign it a context class; a different interpolation/filter is applied to neighborhoods of differing context. It is shown how the context dependent interpolation is computed through ensemble average statistics using high resolution training imagery from which the lower resolution image array data is obtained (simulation). A quadratic least squares (LS) context-free image quality model is described from which the context dependent interpolation coefficients are derived. It is shown how ensembles of high-resolution images can be used to capture the a priori special character of different context classes. As a consequence, a priori information such as the translational invariance of edges along the edge direction, edge discontinuity, and the character of corners is captured and can be used to interpret image array data with greater spatial resolution than would be expected by the Nyquist limit. A Gibb-like artifact associated with this super-resolution is discussed. More realistic context dependent image quality models are needed and a suggestion is made for using a quality model which now is finding application in data compression.

The structural diversity of ABS{sub 3} compounds with d{sup 0} electronic configuration for the B-cation

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

Brehm, John A., E-mail: brehmj@sas.upenn.edu; Bennett, Joseph W.; Schoenberg, Michael Rutenberg

2014-06-14

We use first-principles density functional theory within the local density approximation to ascertain the ground state structure of real and theoretical compounds with the formula ABS{sub 3} (A = K, Rb, Cs, Ca, Sr, Ba, Tl, Sn, Pb, and Bi; and B = Sc, Y, Ti, Zr, V, and Nb) under the constraint that B must have a d{sup 0} electronic configuration. Our findings indicate that none of these AB combinations prefer a perovskite ground state with corner-sharing BS{sub 6} octahedra, but that they prefer phases with either edge- or face-sharing motifs. Further, a simple two-dimensional structure field map createdmore » from A and B ionic radii provides a neat demarcation between combinations preferring face-sharing versus edge-sharing phases for most of these combinations. We then show that by modifying the common Goldschmidt tolerance factor with a multiplicative term based on the electronegativity difference between A and S, the demarcation between predicted edge-sharing and face-sharing ground state phases is enhanced. We also demonstrate that, by calculating the free energy contribution of phonons, some of these compounds may assume multiple phases as synthesis temperatures are altered, or as ambient temperatures rise or fall.« less

White Beam Slits and Pink Beam Slits for the Hard X-ray Nanoprobe Beamline at the Advanced Photon Source

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

Benson, C.; Jaski, Y.; Powers, T.

2007-01-19

A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a cleanmore » cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam.The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.« less

White beam slits and pink beam slits for the hard x-ray nanoprobe beamline at the Advanced Photon Source.

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

Benson, C.; Jaski, Y.; Maser, J.

2007-01-01

A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a cleanmore » cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam. The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.« less

Numerical and experimental investigation of a beveled trailing-edge flow field and noise emission

NASA Astrophysics Data System (ADS)

van der Velden, W. C. P.; Pröbsting, S.; van Zuijlen, A. H.; de Jong, A. T.; Guan, Y.; Morris, S. C.

2016-12-01

Efficient tools and methodology for the prediction of trailing-edge noise experience substantial interest within the wind turbine industry. In recent years, the Lattice Boltzmann Method has received increased attention for providing such an efficient alternative for the numerical solution of complex flow problems. Based on the fully explicit, transient, compressible solution of the Lattice Boltzmann Equation in combination with a Ffowcs-Williams and Hawking aeroacoustic analogy, an estimation of the acoustic radiation in the far field is obtained. To validate this methodology for the prediction of trailing-edge noise, the flow around a flat plate with an asymmetric 25° beveled trailing edge and obtuse corner in a low Mach number flow is analyzed. Flow field dynamics are compared to data obtained experimentally from Particle Image Velocimetry and Hot Wire Anemometry, and compare favorably in terms of mean velocity field and turbulent fluctuations. Moreover, the characteristics of the unsteady surface pressure, which are closely related to the acoustic emission, show good agreement between simulation and experiment. Finally, the prediction of the radiated sound is compared to the results obtained from acoustic phased array measurements in combination with a beamforming methodology. Vortex shedding results in a strong narrowband component centered at a constant Strouhal number in the acoustic spectrum. At higher frequency, a good agreement between simulation and experiment for the broadband noise component is obtained and a typical cardioid-like directivity is recovered.

Evaluation of double drop beads pavement edge lines : SPR project description.

DOT National Transportation Integrated Search

2009-01-01

In UTCA projects 01465 and 04405, the retroreflectivities and the life cycle costs were measured and compared for standard Alabama Department of Transportation (ALDOT) thermoplastic edge : stripes that contained only one size of retroreflective beads...

77 FR 49006 - Buy American Exceptions Under the American Recovery and Reinvestment Act of 2009

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-15

... power cords for the Village at River's Edge project, and to the Hammond Housing Authority for the... CFRFC grant funds, in connection with the Village at River's Edge project. The exception was granted by...

14. Photocopy of a photographca. 1902taken by A.W. Peters showing ...

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

14. Photocopy of a photograph--ca. 1902--taken by A.W. Peters showing Eastwood and his party surveying for the Big Creek Project. The surveying party is visible in the upper right corner. Courtesy Mr. Charles Allan Whitney. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

Facilitating Learnscape Development, Maintenance and Use: Teachers' Perceptions and Self-Reported Practices.

ERIC Educational Resources Information Center

Skamp, Keith; Bergmann, Iris

2001-01-01

Introduces two pilot schools participating in the project Learnscapes, a learning program in which users interact with the environment on school grounds with features such as an edible garden, a poetry corner, or a wildlife corridor. Presents teachers' ideas on the relationship of learnscapes to environmental education and discusses pedagogical…

Role of herbicide treatments and application times in cogongrass eradication under open field infestation scenario

USDA-ARS?s Scientific Manuscript database

A Cogongrass eradication project was conducted from spring 2008 through fall 2011 on natural, open-field Cogongrass infestations at two locations near Tilman's Corner and Bayou La Batre in southwestern Alabama. Treatments consisted of glyphosate alone (4 lb/acre), imazapyr alone (0.75 lb/acre) and ...

Corner Office Interview: Gates Foundation's Deborah Jacobs

ERIC Educational Resources Information Center

Miller, Rebecca

2010-01-01

U.S. libraries gave the world a top talent when Deborah Jacobs left her transformational role as City Librarian of Seattle in 2008 to head the Bill & Melinda Gates Foundation's Global Libraries program, the international sibling to the U.S. Libraries program. The initiative fosters national-scale projects with grantees in transitioning countries…

Window type: paired 2x4 multipaned steel windows flanked by 1x4 ...

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

Window type: paired 2x4 multipaned steel windows flanked by 1x4 multipaned steel casements, breaking building corner. Raised panel door front entry also illustrated. Ground floor detail Building 19, facing north - Harbor Hills Housing Project, 26607 Western Avenue, Lomita, Los Angeles County, CA

Demonstration of a fully differential VGA chip with small THD for ECG acquisition system

NASA Astrophysics Data System (ADS)

Gongli, Xiao; Yuliang, Qin; Weilin, Xu; Baolin, Wei; Jihai, Duan; Xueming, Wei

2015-10-01

We present both a theoretical and experimental demonstration of a fully differential variable gain amplifier (VGA) with small total harmonic distortion (THD) for an electrocardiogram (ECG) acquisition system. Capacitive feedback technology is adopted to reduce the nonlinearity of VGA. The fully differential VGA has been fabricated in SMIC 0.18-μm CMOS process, and it only occupies 0.11 mm2. The measurements are in good agreement with simulation results. Experimental results show that the gain of VGA changes from 6.17 to 43.75 dB with a gain step of 3 dB. The high-pass corner frequency and low-pass corner frequency are around 0.22 Hz and 7.9 kHz, respectively. For each gain configuration, a maximal THD of 0.13% is obtained. The fully differential VGA has a low THD and its key performance parameters are well satisfied with the demands of ECG acquisition system application in the UWB wireless body area network. Project supported by the National Natural Science Foundation of China (Nos. 61264001, 61465004, 61161003, 61166004), the Guangxi Natural Science Foundation (Nos. 2013GXNSFAA019333, 2013GXNSFAA019338), the Science and Technology Research Key Project of Guangxi Department of Education (No. 2013ZD026), and the Innovation Project of GUET Graduate Education (No. GDYCSZ201457).

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

Multimillion Dollar Construction Project Completed in Glenn's Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Kevdzija, Susan L.

2001-01-01

Over the last year, the Glenn Research Center's Icing Research Tunnel (IRT) underwent a major $5.2 million rehabilitation project as part of the Construction of Facilities program. The scope of the project included redesign and replacement of the 55-yr-old heat exchanger, the addition of fan outlet guide vanes for flow conditioning downstream of the 25-ft-diameter fan, and redesign and replacement of the C and D corner-turning vanes. The purpose of the rehabilitation was to replace old portions of the infrastructure and to improve the aerodynamic flow quality in the tunnel.

Development of a Single-Longitudinal-Mode Ho:YAG Laser Based on Corner Cube

NASA Astrophysics Data System (ADS)

Jing, Wu; You-Lun, Ju; Tong-Yu, Dai; Zhen-Guo, Zhang; Bao-Quan, Yao; Yue-Zhu, Wang

2016-04-01

Not Available Supported by the National Natural Science Foundation of China under Grant Nos 61308009 and 61405047, the China Postdoctoral Science Foundation Funded Project under Grant No 2013M540288, the Fundamental Research Funds for the Central Universities under Grant Nos HIT.NSRIF.2014044 and HIT.NSRIF.2015042, the Science Fund for Outstanding Youths of Heilongjiang Province under Grant No JQ201310, and the Heilongjiang Postdoctoral Science Foundation Funded Project under Grant No LBH-Z14085.

A Method of Strengthening Composite/Metal Joints

NASA Technical Reports Server (NTRS)

Polis, Daniel L.

2011-01-01

The term tape setback method denotes a method of designing and fabricating bonded joints between (1) box beams or other structural members made of laminated composite (matrix/ fiber) materials and (2) metal end fittings used to fasten these structural members to other structural members. The basic idea of the tape setback method is to mask the bonded interface between the metallic end fitting and composite member such that the bond does not extend out to the free edges of the composite member. The purpose served by the tape setback method is to strengthen the joints by decoupling stress concentrations from edge defects, which can cause premature failures. A related prior method that serves a similar purpose, involving the use of tapered adherends at the joints, can be too difficult and costly to be acceptable in some applications. The tape setback method offers an easier, less costly alternative. The structural members to which the method was originally applied were box beams in the form of composite tubes having flat faces with rounded corners. The end fittings were plugs made of a low-thermal- expansion nickel/iron alloy (see figure). In computational-simulation studies of tensile and compressive loading of members without tape setback, stresses were found to be concentrated at the free end edges of the composite tubes, and inspection of members that had been subjected to real tension and compression tests showed that cracks started at the free end edges. As applied to these members, the tape setback method makes them less vulnerable to initiation of failure at edge defects produced during fabrication. In real tension tests of comparable members without and with tape setback, the average mean tensile strength of the members with tape setback was found to be 1.9 times that of the members without tape setback.

Recruiting first generation college students into the Geosciences: Alaska's EDGE project

NASA Astrophysics Data System (ADS)

Prakash, A.; Connor, C.

2008-12-01

Funded in 2005-2008, by the National Science Foundation's Geoscience Education Division, the Experiential Discoveries in Geoscience Education (EDGE) project was designed to use glacier and watershed field experiences as venues for geospatial data collected by Alaska's grade 6-12 middle and high school teachers and their students. EDGE participants were trained in GIS and learned to analyze geospatial data to answer questions about the warming Alaska environment and to determine rates of ongoing glacier recession. Important emphasis of the program was the recruitment of Alaska Native students of Inupiat, Yup'ik, Athabascan, and Tlingit populations, living in both rural and urban areas around the state. Twelve of Alaska's 55 school districts have participated in the EDGE program. To engage EDGE students in the practice of scientific inquiry, each was required to carry out a semester scale research project using georeferenced data, guided by their EDGE teacher and mentor. Across Alaska students investigated several Earth systems processes including freezing conditions of lake ice; the changes in water quality in storm drains after rainfall events; movements of moose, bears, and bison across Alaskan landscapes; changes in permafrost depth in western Alaska; and the response of migrating waterfowl to these permafrost changes. Students correlated the substrate beneath their schools with known earthquake intensities; measured cutbank and coastal erosion on northern rivers and southeastern shorelines; tracked salmon infiltration of flooded logging roads; noted the changing behavior of eagles during late winter salmon runs; located good areas for the use of tidal power for energy production; tracked the extent and range of invasive plant species with warming; and the change of forests following deglaciation. Each cohort of EDGE students and teachers finished the program by attended a 3-day EDGE symposium at which students presented their research projects first in a practice sessions at the University and then in an actual competition in a Regional High School Science Fair at which they could qualify to compete at the Intel International Science and Engineering fair. Thirty-four teachers, 30 high school students (over 40 percent of whom were Alaska Native) and over 1000 middle school students (25 percent Alaska natives) participated in EDGE activities, increasing their knowledge of Earth science, GIS skills, and data management and analysis. More information on the EDGE project is available at www.edge.alaska.edu.

INFLIGHT (CREW ACTIVITY) - STS-2 - OUTER SPACE

NASA Image and Video Library

1981-11-16

S81-39573 (12-14 Nov. 1981) --- This photograph was taken during a two-and a fourth-day stay in Earth orbit by astronauts Joe H. Engle, here shaving, and Richard H. Truly, photographer for this frame. A portion of that time was spent in the living area of middeck portion of the 122-ft-long (37 meters) vehicle as the astronauts ate, slept and took care of hygiene matters here. An onboard fire extinguisher is in upper right corner. Partially out of the frame at right edge is a photograph of George W. S. Abbey, Director of Flight Operations at Johnson Space Center. Engle is attired in an onboard constant wear type garment. Photo credit: NASA

Polar User’s Manual.

DTIC Science & Technology

1985-10-01

elements with BOTTON faces. 5. Thin plates may only intersect each other at the edges or corners. 6. Double points must be assigned TOP and BOTTOM sets...10 ExPONEP4T 1.7� INCNE) 1.7B.CZC (NONE) 11 YIELDC FOR IKEV PROTONS 𔃾.9C-CC! INCNE) N.-’O S(ONE) 12 AX oC/ aw FRa PROTONS ..zz0=2 KEY ±.Z:-CCZ...AEV 13 PHCTOCURPE~t Z.90-C:S Aw ..Z 1.91-,cE 1/"’sZ I& SURFACE RESISTIVITY -i.Z.C *0 OH*PS -6.d5-C1! v-Sic is SPACE DISCHARGE POT’L I.3IC*CC; VCLTS 1.Z

SPERTI/PBF. Contextual aerial view after PBF had begun operating, but ...

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

SPERT-I/PBF. Contextual aerial view after PBF had begun operating, but prior to expansion of southwest corner of Reactor Building (PER-620). Camera facing northeast. Reactor Building in center of view. Cooling Tower (PER-720) to its left. Warehouse (PER-625) at lower left was built in 1966. SPERT-I Reactor Building (PER-605) and Instrument Cell Building (PER-604) at right of view. Buried cables and piping proceed from PBF toward lower edge of view to Control Building further south and out of view. Photographer: Farmer. Date: March 26, 1976. INEEL negative no. 76-1344 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

Wulff polyhedra derived from morse potentials and crystal habits of bcc and fcc metal particles

NASA Astrophysics Data System (ADS)

Saito, Yahachi

1981-05-01

Using the broken-bond method and the pairwise potentials of Morse type, relative surface energies were calculated to derive the Wulff polyhedra for bcc and fcc metals. When only the first and the second nearest neighbour interactions are taken into account, the resulting Wulff polyhedron is a rhombic dodecahedron truncated by {100} faces and an octahedron truncated by {100} and {100} faces for bcc and fcc metals, respectively. The truncation degrees calculated are in good agreement with those measured from smoke particles grown in an atmosphere of rarefied inactive gas. The effect of the higher order terms of interactions is simply to make the edges and corners round.

The electric field of a uniformly charged cubic shell

NASA Astrophysics Data System (ADS)

McCreery, Kaitlin; Greenside, Henry

2018-01-01

As an integrative and insightful example for undergraduates learning about electrostatics, we discuss how to use symmetry, Coulomb's law, superposition, Gauss's law, and visualization to understand the electric field E (x ,y ,z ) produced by a uniformly charged cubic shell. We first discuss how to deduce qualitatively, using freshman-level physics, the perhaps surprising fact that the interior electric field is nonzero and has a complex structure, pointing inwards from the middle of each face of the shell and pointing outwards towards each edge and corner. We then discuss how to understand the quantitative features of the electric field by plotting an analytical expression for E along symmetry lines and on symmetry surfaces of the shell.

62. VIEW OF MILL SOLUTION TANKS FLOOR FROM WEST. THE ...

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

62. VIEW OF MILL SOLUTION TANKS FLOOR FROM WEST. THE BOTTOM OF MILL SOLUTION TANK No. 1 IS IN THE LOWER RIGHT QUADRANT UNDER A PILE OF SOLUTION SEDIMENT. JOISTS OF TANK No. 2 ARE ABOVE AND SLIGHTLY LEFT OF No. 1. THE BOTTOM OF THE MILL SOLUTION SURGE TANK WITH ATTACHED DISCHARGE PIPE IS VISIBLE ON LOWER RIGHT HAND EDGE OF VIEW; TANKS ORIGINALLY SAT ON DIAGONAL BEAM CUTTING ACROSS UPPER LEFT CORNER OF VIEW. DISCHARGE LAUNDER FROM THE UNOXIDIZED ORE CIRCUIT PIERCES THE FOUNDATION WALL ABOVE TANK No. 1 (FOR DETAIL SEE SD-2-61). - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

Redetermination of Na(3)TaF(8).

PubMed

Langer, Vratislav; Smrcok, Lubomír; Boca, Miroslav

2010-09-01

The crystal structure of trisodium octafluoridotantalate, Na(3)TaF(8), has been redetermined using diffractometer data collected at 153 K, resulting in more accurate bond distances and angles than obtained from a previous structure determination based on film data. The structure is built from layers running along [101], which are formed by distorted [TaF(8)] antiprisms and [NaF(6)] rectangular bipyramids sharing edges and corners. The individual layers are separated by eight-coordinated Na ions. Two atoms in the asymmetric unit are in special positions: the Ta atom is on a twofold axis in Wyckoff position 4e and one of the Na ions lies on an inversion centre in Wyckoff site 4d.

Experimental and numerical investigation of slabs on ground subjected to concentrated loads

NASA Astrophysics Data System (ADS)

Øverli, Jan

2014-09-01

An experimental program is presented where a slab on ground is subjected to concentrated loading at the centre, the edges and at the corners. Analytical solutions for the ultimate load capacity fit well with the results obtained in the tests. The non-linear behaviour of the slab is captured by performing nonlinear finite element analyses. The soil is modelled as a no-tension bedding and a smeared crack approach is employed for the concrete. Through a parametric study, the finite element model has been used to assess the influence of subgrade stiffness and shrinkage. The results indicate that drying shrinkage can cause severe cracking in slabs on grade.

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.

Impact of edge lines on safety of rural two-lane highways.

DOT National Transportation Integrated Search

2005-10-01

This report documents the results of the project for Impact of Edge Lines on Safety of Rural Two Lane Highways. This research project was initiated in the effort of compliance with the updated version of the Manual on Uniform Traffic Control De...

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

Firebrand Production from Building Components Fitted with Siding Treatments

PubMed Central

Suzuki, Sayaka; Manzello, Samuel L.

2016-01-01

Firebrand production from real-scale building components under well-controlled laboratory conditions was investigated. Re-entrant corner assemblies were ignited and during the combustion process, firebrands were collected to determine the size/mass distribution generated from such real-scale building components under varying wind speed. In prior work, a unique ignition methodology was developed to generate firebrands from re-entrant corner assemblies constructed of wood studs and oriented strand board (OSB). In this study, this ignition methodology was applied to re-entrant corners constructed from wood studs/OSB but fitted with actual siding treatments (tar paper and cedar siding) to determine the influence of siding treatments on firebrand generation from wall assemblies. Firebrands were collected with pans filled with water, and then the size and mass of firebrands were measured after drying. The size and mass distributions of firebrands collected in this study were compared with the data from prior component tests as well as the limited studies available in the literature on this topic. Some firebrands were found to be lighter for a given projected area than others, likely produced from cedar siding or tar paper. The effects of applied siding treatments on firebrand production are discussed in detail. PMID:27114643

Firebrand Production from Building Components Fitted with Siding Treatments.

PubMed

Suzuki, Sayaka; Manzello, Samuel L

2016-02-01

Firebrand production from real-scale building components under well-controlled laboratory conditions was investigated. Re-entrant corner assemblies were ignited and during the combustion process, firebrands were collected to determine the size/mass distribution generated from such real-scale building components under varying wind speed. In prior work, a unique ignition methodology was developed to generate firebrands from re-entrant corner assemblies constructed of wood studs and oriented strand board (OSB). In this study, this ignition methodology was applied to re-entrant corners constructed from wood studs/OSB but fitted with actual siding treatments (tar paper and cedar siding) to determine the influence of siding treatments on firebrand generation from wall assemblies. Firebrands were collected with pans filled with water, and then the size and mass of firebrands were measured after drying. The size and mass distributions of firebrands collected in this study were compared with the data from prior component tests as well as the limited studies available in the literature on this topic. Some firebrands were found to be lighter for a given projected area than others, likely produced from cedar siding or tar paper. The effects of applied siding treatments on firebrand production are discussed in detail.

GIS integration of the 1:75,000 Romanian topographic map series from the World War I

NASA Astrophysics Data System (ADS)

Timár, G.; Mugnier, C. J.

2009-04-01

During the WWI, the Kingdom of Romania developed a 1:75,000 topographic map series, covering not only the actual territory of the country (the former Danube Principalities and Dobrogea) but also Bessarabia (now the Republic of Moldova), which was under Russian rule. The map sheets were issued between 1914 and 1917. The whole map consists of two zones; Columns A-F are the western zone, while Columns G-Q are belonging to the eastern one. To integrate the scanned map sheets to a geographic information system (GIS), the parameters of the map projection and the geodetic datum should be defined as well as the sheet labelling system. The sheets have no grid lines indicated; most of them have latitude and longitude lines but some of them have no coordinate descriptions. The sheets, however, can be rectified using their four corners as virtual control points, and using the following grid and datum parameters: Eastern zone: • Projection type: Bonne. • Projection center: latitude=46d 30m; longitude=27d 20m 13.35s (from Greenwich). • Base ellipsoid: Bessel 1841 • Datum parameters (from local to WGS84): dX=+875 m; dY=-119 m; dZ=+313 m. • Sheet size: 40*40 kilometers, projection center is the NW corner of the 779 (Column L; Row VII) sheet. Western zone: • Projection type: Bonne. • Projection center: latitude=45d; longitude=26d 6m 41.18s (from Greenwich); • Base ellipsoid: Bessel 1841 • Datum parameters (from local to WGS84): dX=+793 m; dY=+364 m; dZ=+173 m. • Sheet size: 0.6*0.4 grad (new degrees), except Column F, which is wider to east to fill the territory to the zone boundary. In Columns E and F geographic coordinates are indicated in new degrees, with the prime meridian of Bucharest. Apart from the system of columns and rows, each sheet has its own label of three or four digit. The last two digit correspond to the column number (69 for Column A going up to 84 for Column Q) while the first digit(s) refer directly to row number (1-15). During the rectification process, the coordinates of the corners (the control points) should be defined in the respective Bonne zone projected coordinates. It can be done by simple additions in the eastern zone but it needs conversion from geographic to projected coordinates in the western one. The general accuracy of this geo-referencing method is up to 200 meters - this error is the same in the 1:75,000 series of the Habsburg Empire made from the 1880s.

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.

Analytical and Experimental Study of Flow Through an Axial Turbine Stage with a Nonuniform Inlet Radial Temperature Profile

NASA Technical Reports Server (NTRS)

Schwab, J. R.; Stabe, R. G.; Whitney, W. J.

1983-01-01

Results are presented for a typical nonuniform inlet radial temperature profile through an advanced single-stage axial turbine and compared with the results obtained for a uniform profile. Gas temperature rises of 40 K to 95 K are predicted at the hub and tip corners at the trailing edges of the pressure surfaces in both the stator and rotor due to convection of hot fluid from the mean by the secondary flow. The inlet temperature profile is shown to be mixed out at the rotor exit survey plane (2.3 axial chords downstream of the rotor trailing edge) in both the analysis and the experiment. The experimental rotor exit angle profile for the nonuniform inlet temperature profile indicates underturning at the tip caused by increased clearance. Severe underturning also occurs at the mean, both with and without the nonuniform inlet temperature profile. The inviscid rotational flow code used in the analysis fails to predict the underturning at the mean, which may be caused by viscous effects.

Analytical and experimental study of flow through an axial turbine stage with a nonuniform inlet radial temperature profile

NASA Technical Reports Server (NTRS)

Schwab, J. R.; Stabe, R. G.; Whitney, W. J.

1983-01-01

Results are presented for a typical nonuniform inlet radial temperature profile through an advanced single-stage axial turbine and compared with the results obtained for a uniform profile. Gas temperature rises of 40 K to 95 K are predicted at the hub and tip corners at the trailing edges of the pressure surfaces in both the stator and rotor due to convection of hot fluid from the mean by the secondary flow. The inlet temperature profile is shown to be mixed out at the rotor exit survey plane (2.3 axial chords downstream of the rotor trailing edge) in both the analysis and the experiment. The experimental rotor exit angle profile for the nonuniform inlet temperature profile indicates underturning at the tip caused by increased clearance. Severe underturning also occurs at the mean, both with and without the nonuniform inlet temperature profile. The inviscid rotational flow code used in the analysis fails to predict the underturning at the mean, which may be caused by viscous effects. Previously announced in STAR as N83-27958

Design and development of LED-based irregular leather area measuring machine

NASA Astrophysics Data System (ADS)

Adil, Rehan; Khan, Sarah Jamal

2012-01-01

Using optical sensor array, a precision motion control system in a conveyer follows the irregular shaped leather sheet to measure its surface area. In operation, irregular shaped leather sheet passes on conveyer belt and optical sensor array detects the leather sheet edge. In this way outside curvature of the leather sheet is detected and is then feed to the controller to measure its approximate area. Such system can measure irregular shapes, by neglecting rounded corners, ellipses etc. To minimize the error in calculating surface area of irregular curve to the above mentioned system, the motion control system only requires the footprint of the optical sensor to be small and the distance between the sensors is to be minimized. In the proposed technique surface area measurement of irregular shaped leather sheet is done by defining velocity and detecting position of the move. The motion controller takes the information and creates the necessary edge profile on point-to-point bases. As a result irregular shape of leather sheet is mapped and is then feed to the controller to calculate surface area.

An approximate stationary solution for multi-allele neutral diffusion with low mutation rates.

PubMed

Burden, Conrad J; Tang, Yurong

2016-12-01

We address the problem of determining the stationary distribution of the multi-allelic, neutral-evolution Wright-Fisher model in the diffusion limit. A full solution to this problem for an arbitrary K×K mutation rate matrix involves solving for the stationary solution of a forward Kolmogorov equation over a (K-1)-dimensional simplex, and remains intractable. In most practical situations mutations rates are slow on the scale of the diffusion limit and the solution is heavily concentrated on the corners and edges of the simplex. In this paper we present a practical approximate solution for slow mutation rates in the form of a set of line densities along the edges of the simplex. The method of solution relies on parameterising the general non-reversible rate matrix as the sum of a reversible part and a set of (K-1)(K-2)/2 independent terms corresponding to fluxes of probability along closed paths around faces of the simplex. The solution is potentially a first step in estimating non-reversible evolutionary rate matrices from observed allele frequency spectra. Copyright © 2016 Elsevier Inc. All rights reserved.

Development of n+-in-p large-area silicon microstrip sensors for very high radiation environments - ATLAS12 design and initial results

NASA Astrophysics Data System (ADS)

Unno, Y.; Edwards, S. O.; Pyatt, S.; Thomas, J. P.; Wilson, J. A.; Kierstead, J.; Lynn, D.; Carter, J. R.; Hommels, L. B. A.; Robinson, D.; Bloch, I.; Gregor, I. M.; Tackmann, K.; Betancourt, C.; Jakobs, K.; Kuehn, S.; Mori, R.; Parzefall, U.; Wiik-Fucks, L.; Clark, A.; Ferrere, D.; Gonzalez Sevilla, S.; Ashby, J.; Blue, A.; Bates, R.; Buttar, C.; Doherty, F.; Eklund, L.; McMullen, T.; McEwan, F.; O`Shea, V.; Kamada, S.; Yamamura, K.; Ikegami, Y.; Nakamura, K.; Takubo, Y.; Nishimura, R.; Takashima, R.; Chilingarov, A.; Fox, H.; Affolder, A. A.; Allport, P. P.; Casse, G.; Dervan, P.; Forshaw, D.; Greenall, A.; Wonsak, S.; Wormald, M.; Cindro, V.; Kramberger, G.; Mandic, I.; Mikuz, M.; Gorelov, I.; Hoeferkamp, M.; Palni, P.; Seidel, S.; Taylor, A.; Toms, K.; Wang, R.; Hessey, N. P.; Valencic, N.; Arai, Y.; Hanagaki, K.; Dolezal, Z.; Kodys, P.; Bohm, J.; Mikestikova, M.; Bevan, A.; Beck, G.; Ely, S.; Fadeyev, V.; Galloway, Z.; Grillo, A. A.; Martinez-McKinney, F.; Ngo, J.; Parker, C.; Sadrozinski, H. F.-W.; Schumacher, D.; Seiden, A.; French, R.; Hodgson, P.; Marin-Reyes, H.; Parker, K.; Paganis, S.; Jinnouchi, O.; Motohashi, K.; Todome, K.; Yamaguchi, D.; Hara, K.; Hagihara, M.; Garcia, C.; Jimenez, J.; Lacasta, C.; Marti i Garcia, S.; Soldevila, U.

2014-11-01

We have been developing a novel radiation-tolerant n+-in-p silicon microstrip sensor for very high radiation environments, aiming for application in the high luminosity large hadron collider. The sensors are fabricated in 6 in., p-type, float-zone wafers, where large-area strip sensor designs are laid out together with a number of miniature sensors. Radiation tolerance has been studied with ATLAS07 sensors and with independent structures. The ATLAS07 design was developed into new ATLAS12 designs. The ATLAS12A large-area sensor is made towards an axial strip sensor and the ATLAS12M towards a stereo strip sensor. New features to the ATLAS12 sensors are two dicing lines: standard edge space of 910 μm and slim edge space of 450 μm, a gated punch-through protection structure, and connection of orphan strips in a triangular corner of stereo strips. We report the design of the ATLAS12 layouts and initial measurements of the leakage current after dicing and the resistivity of the wafers.

Surface complexation model for multisite adsorption of copper(II) onto kaolinite

NASA Astrophysics Data System (ADS)

Peacock, Caroline L.; Sherman, David M.

2005-08-01

We measured the adsorption of Cu(II) onto kaolinite from pH 3-7 at constant ionic strength. EXAFS spectra show that Cu(II) adsorbs as (CuO 4H n) n-6 and binuclear (Cu 2O 6H n) n-8 inner-sphere complexes on variable-charge ≡AlOH sites and as Cu 2+ on ion exchangeable ≡X-H + sites. Sorption isotherms and EXAFS spectra show that surface precipitates have not formed at least up to pH 6.5. Inner-sphere complexes are bound to the kaolinite surface by corner-sharing with two or three edge-sharing Al(O,OH) 6 polyhedra. Our interpretation of the EXAFS data are supported by ab initio (density functional theory) geometries of analog clusters simulating Cu complexes on the {110} and {010} crystal edges and at the ditrigonal cavity sites on the {001}. Having identified the bidentate (≡AlOH) 2Cu(OH) 20, tridentate (≡Al 3O(OH) 2)Cu 2(OH) 30 and ≡X-Cu 2+ surface complexes, the experimental copper(II) adsorption data can be fit to the reactions

Wind Tunnel Tests for Wind Pressure Distribution on Gable Roof Buildings

PubMed Central

2013-01-01

Gable roof buildings are widely used in industrial buildings. Based on wind tunnel tests with rigid models, wind pressure distributions on gable roof buildings with different aspect ratios were measured simultaneously. Some characteristics of the measured wind pressure field on the surfaces of the models were analyzed, including mean wind pressure, fluctuating wind pressure, peak negative wind pressure, and characteristics of proper orthogonal decomposition results of the measured wind pressure field. The results show that extremely high local suctions often occur in the leading edges of longitudinal wall and windward roof, roof corner, and roof ridge which are the severe damaged locations under strong wind. The aspect ratio of building has a certain effect on the mean wind pressure coefficients, and the effect relates to wind attack angle. Compared with experimental results, the region division of roof corner and roof ridge from AIJ2004 is more reasonable than those from CECS102:2002 and MBMA2006.The contributions of the first several eigenvectors to the overall wind pressure distributions become much bigger. The investigation can offer some basic understanding for estimating wind load distribution on gable roof buildings and facilitate wind-resistant design of cladding components and their connections considering wind load path. PMID:24082851

Geometrically robust image watermarking by sector-shaped partitioning of geometric-invariant regions.

PubMed

Tian, Huawei; Zhao, Yao; Ni, Rongrong; Cao, Gang

2009-11-23

In a feature-based geometrically robust watermarking system, it is a challenging task to detect geometric-invariant regions (GIRs) which can survive a broad range of image processing operations. Instead of commonly used Harris detector or Mexican hat wavelet method, a more robust corner detector named multi-scale curvature product (MSCP) is adopted to extract salient features in this paper. Based on such features, disk-like GIRs are found, which consists of three steps. First, robust edge contours are extracted. Then, MSCP is utilized to detect the centers for GIRs. Third, the characteristic scale selection is performed to calculate the radius of each GIR. A novel sector-shaped partitioning method for the GIRs is designed, which can divide a GIR into several sector discs with the help of the most important corner (MIC). The watermark message is then embedded bit by bit in each sector by using Quantization Index Modulation (QIM). The GIRs and the divided sector discs are invariant to geometric transforms, so the watermarking method inherently has high robustness against geometric attacks. Experimental results show that the scheme has a better robustness against various image processing operations including common processing attacks, affine transforms, cropping, and random bending attack (RBA) than the previous approaches.

A 4-node assumed-stress hybrid shell element with rotational degrees of freedom

NASA Technical Reports Server (NTRS)

Aminpour, Mohammad A.

1990-01-01

An assumed-stress hybrid/mixed 4-node quadrilateral shell element is introduced that alleviates most of the deficiencies associated with such elements. The formulation of the element is based on the assumed-stress hybrid/mixed method using the Hellinger-Reissner variational principle. The membrane part of the element has 12 degrees of freedom including rotational or drilling degrees of freedom at the nodes. The bending part of the element also has 12 degrees of freedom. The bending part of the element uses the Reissner-Mindlin plate theory which takes into account the transverse shear contributions. The element formulation is derived from an 8-node isoparametric element. This process is accomplished by assuming quadratic variations for both in-plane and out-of-plane displacement fields and linear variations for both in-plane and out-of-plane rotation fields along the edges of the element. In addition, the degrees of freedom at midside nodes are approximated in terms of the degrees of freedom at corner nodes. During this process the rotational degrees of freedom at the corner nodes enter into the formulation of the element. The stress field are expressed in the element natural-coordinate system such that the element remains invariant with respect to node numbering.

Distribution of slab-derived fluids around the edge of the Philippine Sea Plate from Central to Northeast Japan

NASA Astrophysics Data System (ADS)

Nakamura, Hitomi; Iwamori, Hikaru; Ishizuka, Osamu; Nishizawa, Tatsuji

2018-01-01

Marginal parts of a plate and subducting slab can play important roles in geodynamics. This is because in areas where a plate interacts with other plates or with the mantle thermal, geochemical, and mechanical interactions are expected. The Philippine Sea (PHS) slab that subducts beneath the Japan arcs has such an edge. To examine the relationship between arc magmatism and the slab edge in the transition zone from Northeast Japan to Central Japan, we investigated isotopic systematics of the regional volcanic rocks, incorporating data from literature and new data for five isotopic ratios of Sr, Nd, and Pb. The new data included major element compositions of 22 samples from the back-arc area, and 5 isotopic ratios for 6 samples selected from Pleistocene to early Quaternary epochs. Consequently, several findings were determined based on the spatial variation of the isotopic ratios and the estimated amount of slab-derived fluid: (1) the amount of fluid derived from the two subducting slabs (i.e., the Pacific slab and the PHS slab) decreases northward from a significantly high value ( 5 wt% fluid added to the source mantle), away from the seismically determined edge of the PHS slab; (2) the proportion of the PHS component in the total slab-derived fluid also decays northward; and (3) the PHS component spreads to the north beyond the seismically determined edge of the PHS slab. These observations strongly suggest that the existence of an aseismic PHS slab beneath southernmost parts of Northeast Japan delivers the PHS component to the arc magmatism. As was indicated by previous geodynamical studies, subduction of the PHS and PAC slabs may generate suction force towards the corner of mantle wedge, which might account for the large amount of fluid near the seismically determined slab edge as described in (1) above.

Experimental investigation on laser-induced plasma ignition of hydrocarbon fuel in scramjet engine at takeover flight conditions

NASA Astrophysics Data System (ADS)

Li, Xipeng; Liu, Weidong; Pan, Yu; Yang, Leichao; An, Bin

2017-09-01

Laser-induced plasma ignition of an ethylene fuelled cavity is successfully conducted in a model scramjet engine combustor with dual cavities. The simulated flight condition corresponds to takeover flight Mach 4, with isolator entrance Mach number of 2.1, the total pressure of 0.65 MPa and stagnation temperature of 947 K. Ethylene is injected 35 mm upstream of cavity flameholder from four orifices with 2-mm-diameter. The 1064 nm laser beam, from a Q-switched Nd:YAG laser source running at 10 Hz and 940 mJ per pulse, is focused into cavity for ignition. High speed photography is used to capture the transient ignition process. The laser-induced gas breakdown, flame kernel generation and propagation are all recorded and ensuing stable supersonic combustion is established in cavity. The highly ionized plasma zone is almost round at starting, and then the surface of the flame kernel is wrinkled severely in 150 μs after the laser pulse due to the strong turbulence flow in cavity. The flame kernel is found rotating anti-clockwise and gradually moves upstream as the entrainment of circulation flow in cavity. The flame is stabilized at the corner of the cavity for about 200 μs, and then spreads from leading edge to trailing edge via the under part of shear layer to fully fill the entire cavity. The corner recirculation zone of cavity is of great importance for flame spreading. Eventually, a cavity shear-layer stabilized combustion is established in the supersonic flow roughly 2.9 ms after the laser pulse. Both the temporal evolution of normalized chemiluminescence intensity and normalized flame area show that the entire ignition process can be divided into four stages, which are referred as turbulent dissipation stage, combustion enhancement stage, reverting stage and combustion stabilization stage. The results show promising potentials of laser induced plasma for ignition in real scramjets.

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.

Overview of Edge Simulation Laboratory (ESL)

NASA Astrophysics Data System (ADS)

Cohen, R. H.; Dorr, M.; Hittinger, J.; Rognlien, T.; Umansky, M.; Xiong, A.; Xu, X.; Belli, E.; Candy, J.; Snyder, P.; Colella, P.; Martin, D.; Sternberg, T.; van Straalen, B.; Bodi, K.; Krasheninnikov, S.

2006-10-01

The ESL is a new collaboration to build a full-f electromagnetic gyrokinetic code for tokamak edge plasmas using continuum methods. Target applications are edge turbulence and transport (neoclassical and anomalous), and edge-localized modes. Initially the project has three major threads: (i) verification and validation of TEMPEST, the project's initial (electrostatic) edge code which can be run in 4D (neoclassical and transport-timescale applications) or 5D (turbulence); (ii) design of the next generation code, which will include more complete physics (electromagnetics, fluid equation option, improved collisions) and advanced numerics (fully conservative, high-order discretization, mapped multiblock grids, adaptivity), and (iii) rapid-prototype codes to explore the issues attached to solving fully nonlinear gyrokinetics with steep radial gradiens. We present a brief summary of the status of each of these activities.

LBP-based penalized weighted least-squares approach to low-dose cone-beam computed tomography reconstruction

NASA Astrophysics Data System (ADS)

Ma, Ming; Wang, Huafeng; Liu, Yan; Zhang, Hao; Gu, Xianfeng; Liang, Zhengrong

2014-03-01

Cone-beam computed tomography (CBCT) has attracted growing interest of researchers in image reconstruction. The mAs level of the X-ray tube current, in practical application of CBCT, is mitigated in order to reduce the CBCT dose. The lowering of the X-ray tube current, however, results in the degradation of image quality. Thus, low-dose CBCT image reconstruction is in effect a noise problem. To acquire clinically acceptable quality of image, and keep the X-ray tube current as low as achievable in the meanwhile, some penalized weighted least-squares (PWLS)-based image reconstruction algorithms have been developed. One representative strategy in previous work is to model the prior information for solution regularization using an anisotropic penalty term. To enhance the edge preserving and noise suppressing in a finer scale, a novel algorithm combining the local binary pattern (LBP) with penalized weighted leastsquares (PWLS), called LBP-PWLS-based image reconstruction algorithm, is proposed in this work. The proposed LBP-PWLS-based algorithm adaptively encourages strong diffusion on the local spot/flat region around a voxel and less diffusion on edge/corner ones by adjusting the penalty for cost function, after the LBP is utilized to detect the region around the voxel as spot, flat and edge ones. The LBP-PWLS-based reconstruction algorithm was evaluated using the sinogram data acquired by a clinical CT scanner from the CatPhan® 600 phantom. Experimental results on the noiseresolution tradeoff measurement and other quantitative measurements demonstrated its feasibility and effectiveness in edge preserving and noise suppressing in comparison with a previous PWLS reconstruction algorithm.

Steering Control in a Low-Cost Driving Simulator: A Case for the Role of Virtual Vehicle Cab.

PubMed

Mecheri, Sami; Lobjois, Régis

2018-04-01

The aim of this study was to investigate steering control in a low-cost driving simulator with and without a virtual vehicle cab. In low-cost simulators, the lack of a vehicle cab denies driver access to vehicle width, which could affect steering control, insofar as locomotor adjustments are known to be based on action-scaled visual judgments of the environment. Two experiments were conducted in which steering control with and without a virtual vehicle cab was investigated in a within-subject design, using cornering and straight-lane-keeping tasks. Driving around curves without vehicle cab information made drivers deviate more from the lane center toward the inner edge in right (virtual cab = 4 ± 19 cm; no cab = 42 ± 28 cm; at the apex of the curve, p < .001) but not in left curves. More lateral deviation from the lane center toward the edge line was also found in driving without the virtual cab on straight roads (virtual cab = 21 ± 28 cm; no cab = 36 ± 27 cm; p < .001), whereas driving stability and presence ratings were not affected. In both experiments, the greater lateral deviation in the no-cab condition led to significantly more time driving off the lane. The findings strongly suggest that without cab information, participants underestimate the distance to the right edge of the car (in contrast to the left edge) and thus vehicle width. This produces considerable differences in the steering trajectory. Providing a virtual vehicle cab must be encouraged for more effectively capturing drivers' steering control in low-cost simulators.

Time for a Change; Spirit's View on Sol 1843 (Stereo)

NASA Technical Reports Server (NTRS)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11973 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11973

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends.

This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.'

The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

This view is presented as a cylindrical-perspective projection with geometric seam correction.

View Ahead After Spirit's Sol 1861 Drive (Stereo)

NASA Technical Reports Server (NTRS)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11977 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11977

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images combined into this stereo, 210-degree view of the rover's surroundings during the 1,861st to 1,863rd Martian days, or sols, of Spirit's surface mission (March 28 to 30, 2009).

This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

The center of the scene is toward the south-southwest. East is on the left. West-northwest is on the right.

The rover had driven 22.7 meters (74 feet) southwestward on Sol 1861 before beginning to take the frames in this view. The drive brought Spirit past the northwestern corner of Home Plate.

In this view, the western edge of Home Plate is on the portion of the horizon farthest to the left. A mound in middle distance near the center of the view is called 'Tsiolkovsky' and is about 40 meters (about 130 feet) from the rover's position.

This view is presented as a cylindrical-perspective projection with geometric seam correction.

Text extraction method for historical Tibetan document images based on block projections

NASA Astrophysics Data System (ADS)

Duan, Li-juan; Zhang, Xi-qun; Ma, Long-long; Wu, Jian

2017-11-01

Text extraction is an important initial step in digitizing the historical documents. In this paper, we present a text extraction method for historical Tibetan document images based on block projections. The task of text extraction is considered as text area detection and location problem. The images are divided equally into blocks and the blocks are filtered by the information of the categories of connected components and corner point density. By analyzing the filtered blocks' projections, the approximate text areas can be located, and the text regions are extracted. Experiments on the dataset of historical Tibetan documents demonstrate the effectiveness of the proposed method.

Low Reynolds Number Wing Transients in Rotation and Translation

NASA Astrophysics Data System (ADS)

Jones, Anya; Schlueter, Kristy

2012-11-01

The unsteady aerodynamic forces and flow fields generated by a wing undergoing transient motions in both rotation and translation were investigated. An aspect ratio 2 flat plate wing at a 45 deg angle of attack was driven over 84 deg of rotation (3 chord-lengths of travel at 3/4 span) and 3 and 10 chord-lengths of translation in quiescent water at Reynolds numbers between 2,500 and 15,000. Flow visualization on the rotating wing revealed a leading edge vortex that lifted off of the wing surface, but remained in the vicinity of the wing for the duration of the wing stroke. A second spanwise vortex with strong axial flow was also observed. As the tip vortex grew, the leading edge vortex joined the tip vortex in a loop-like structure over the aft half of the wing. Near the leading edge, spanwise flow in the second vortex became entrained in the tip vortex near the corner of the wing. Unsteady force measurements revealed that lift coefficient increased through the constant-velocity portion of the wing stroke. Forces were compared for variations in wing acceleration and Reynolds number for both rotational and translational motions. The effect of tank blockage was investigated by repeating the experiments on multiple wings, varying the distance between the wing tip and tank wall. U.S. Air Force Research Laboratory, Summer Faculty Fellowship Program.

Commissioning a hobby cutting device for radiochromic film preparation.

PubMed

Zolfaghari, Somayeh; Francis, Kirby E; Kairn, Tanya; Crowe, Scott B

2017-06-01

In addition to a high spatial resolution and well characterised dose response, one of the major advantages of radiochromic film as a dosimeter is that sheets of film can be cut into pieces suitable for use as calibration films, and for in vivo and phantom measurements. The cutting of film is typically done using scissors or a guillotine, and this process can be time-consuming, limited in precision, requires extensive handling and does not allow holes to be cut from the film without cutting from an existing edge. This study investigated the use of a Brother ScanNCut hobby cutting system for EBT3 film preparation. The optimal operating parameters (blade size, pressure, speed) that resulted in precise cuts with minimal delamination at cut edges were identified using test cutting patterns. These parameters were then used to cut a large film insert for a stereotactic head phantom for comparison against an insert cut with scissors. While the hobby cutting system caused a wider region of delamination at the film edge (1.8 mm) compared to scissors (1 mm), the hobby cutting system was found to be able to produce reproducible cuts more efficiently and more accurately than scissors. The use of the hobby cutting system is recommended for complex phantom inserts (containing sharp corners or holes for alignment rods) or in situations where large numbers of film pieces need to be prepared.

Final Report Navajo Transmission Project (NTP)

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

Bennie Hoisington; Steven Begay

2006-09-14

The Diné Power Authority is developing the Navajo Transmission Project (NTP) to relieve the constraints on the transmission of electricity west of the Four Corners area and to improve the operation flexibility and reliability of the extra-high-voltage transmission system in the region. The NTP creates the wholesale transmission capacity for more economical power transfers, sales, and purchases in the region. It will facilitate the development of Navajo energy resources, improve economic conditions on the Navajo Nation as well as allow DPA to participate in the western electrical utility industry.

First Article Testing of the USMC Container Consolidation Pallet Manufactured by Grate Pallet Solutions

DTIC Science & Technology

2009-05-28

posts use a small sliding “ latch ” to insure they remain in place (Appendix 2, Figure 4). AFPTEF Report No. 09-R-02 USMC CCP AFPTEF Project No. 09...A total of 8 inflated air bladders, measuring 30 in. x 30 in. before inflation, shall be wedged between the end panel and each shelf load, and the...sliding “ latch ”. AFPTEF Report No. 09-R-02 USMC CCP AFPTEF Project No. 09-P-104 25 Figure 5. Corner post indexing tab and lockable slide

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.

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

The Cutting Edge: Workplace English. Instructional Guide.

ERIC Educational Resources Information Center

El Paso Community Coll., TX. Literacy Center.

The instructional guide for the Cutting Edge workplace literacy program, a cooperative project of El Paso Community College (Texas) and Levi Strauss and Company, is an expanded version of one appendix the project handbook. It describes and provides an instructional model for the three-part, job-specific, video-based program of English as a Second…

Evaluation of the Safety Edge application in Oregon.

DOT National Transportation Integrated Search

2012-03-01

This report summarizes a recent assessment of the Safety Edge SM that was performed to determine the feasibility of using this pavement edge treatment on Oregon construction projects. The report includes a review of research that has been published a...

Evaluation of the safety edge application in Oregon.

DOT National Transportation Integrated Search

2012-03-01

This report summarizes a recent assessment of the Safety Edge SM that was performed to determine the feasibility of using this pavement edge treatment on Oregon construction projects. The report includes a review of research that has been published a...

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.

Trisodium citrate, Na 3 (C 6 H 5 O 7 )

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

Rammohan, Alagappa; Kaduk, James A.

2016-05-10

The crystal structure of anhydrous trisodium citrate, Na 3(C 6H 5O 7), has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory (DFT). There are two independent five-coordinate Na +and one six-coordinate Na +cations in the asymmetric unit. The [NaO 5] and [NaO 6] polyhedra share edges and corners to form a three-dimensional framework. There are channels parallel to theaandbaxes in which the remainder of the citrate anions reside. The only hydrogen bonds are an intramolecular one between the hydroxy group and one of the terminal carboxylate O atoms and an intermolecular onemore » between a methylene group and the hydroxyl O atom.« less

Pilot Fullerton plans menu as packaged food and beverages float around him

NASA Image and Video Library

1982-03-31

S82-28912 (March 1982) --- This picture, photographed with a 35mm camera operated by astronaut Jack R. Lousma, STS-3 commander, shows astronaut C. Gordon Fullerton, crew pilot, busy with mealtime preparations aboard the Earth-orbiting Columbia. The astronaut has positioned himself in the corner of the middeck area. Fullerton holds a beverage in his right hand in an accordion-like squeeze dispenser. Many packages of pre-packaged dehydrated foods and other meal items can be seen in the photo. Many are fastened to the locker doors and to trays in the locker doors by velcro. Reminiscent of STS-2 days, a portrait of George W. S. Abbey, director of flight operations at JSC, is at left edge. Photo credit: NASA

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.

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.

Mexico, Arizona, Gulf of California as seen from Apollo 6 unmanned spacecraft

NASA Image and Video Library

1968-04-04

AS06-02-1436 (4 April 1968) --- View of the mouth of the Colorado River and the Gulf of California in northwestern Mexico as photographed from the unmanned Apollo 6 (Spacecraft 020/Saturn 502) space mission. Altitude of the spacecraft at the time picture was taken was 120 nautical miles. NORTH IS TOWARD LEFT SIDE OF PICTURE. At bottom edge of photograph is Baja California. In the upper left corner is the Mexican state of Sonora showing the Sonoran Desert and the Pinacate Mountains. This photograph was made three hours and seven minutes after liftoff using Eastman Kodak SO-121 high resolution aerial Ektachrome film (exposure setting was f/5.6 at 1/500 second) in a J.A. Maurer model 2200 camera.

What do you measure when you measure the Hall effect?

NASA Astrophysics Data System (ADS)

Koon, D. W.; Knickerbocker, C. J.

1993-02-01

A formalism for calculating the sensitivity of Hall measurements to local inhomogeneities of the sample material or the magnetic field is developed. This Hall weighting function g(x,y) is calculated for various placements of current and voltage probes on square and circular laminar samples. Unlike the resistivity weighting function, it is nonnegative throughout the entire sample, provided all probes lie at the edge of the sample. Singularities arise in the Hall weighting function near the current and voltage probes except in the case where these probes are located at the corners of a square. Implications of the results for cross, clover, and bridge samples, and the implications of our results for metal-insulator transition and quantum Hall studies are discussed.

Compact cell-centered discretization stencils at fine-coarse block structured grid interfaces

NASA Astrophysics Data System (ADS)

Pletzer, Alexander; Jamroz, Ben; Crockett, Robert; Sides, Scott

2014-03-01

Different strategies for coupling fine-coarse grid patches are explored in the context of the adaptive mesh refinement (AMR) method. We show that applying linear interpolation to fill in the fine grid ghost values can produce a finite volume stencil of comparable accuracy to quadratic interpolation provided the cell volumes are adjusted. The volume of fine cells expands whereas the volume of neighboring coarse cells contracts. The amount by which the cells contract/expand depends on whether the interface is a face, an edge, or a corner. It is shown that quadratic or better interpolation is required when the conductivity is spatially varying, anisotropic, the refinement ratio is other than two, or when the fine-coarse interface is concave.

Elementary Career Education Units for Integration in Subject Areas at Grades Kindergarten through Six. Project SPAN.

ERIC Educational Resources Information Center

Bell, Lorraine P., Comp.

Units in the curriculum guide are presented in two sections, K-3 and 4-6, and emphasize hands-on activities, role-playing, resource persons, field trips, and classroom career corners. Organized on the career cluster concept, the K-3 units cover self-concept, home and family, familiar community occupations, zoo animals, travel, school, and the…

Connecting for High Potential... "Here Comes Summer." CHP Issue 27

ERIC Educational Resources Information Center

Danielian, Jeff; Nilles, Kathleen

2015-01-01

Summer vacation is right around the corner! However, just as quickly as summer approaches, it also passes in the blink of an eye. This time of year, both parents and teachers face the same dilemma: Should high-ability kids stay busy with summer projects, courses, sports, camps, and travel...or should they be allowed to completely unplug with no…

Capacities Facilitating School Change Involving Project-Based Learning at the Middle School Level

ERIC Educational Resources Information Center

Browder, Lee Shane

2014-01-01

With schools continuing to fall short of No Child Left Behind standards and with future challenges just around the corner, educators must identify and make positive changes in schools. Researchers must work to recognize and exhibit how student achievement is fostered and inform educators of options on how to move in a positive direction according…

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

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.

Exact solution of corner-modified banded block-Toeplitz eigensystems

NASA Astrophysics Data System (ADS)

Cobanera, Emilio; Alase, Abhijeet; Ortiz, Gerardo; Viola, Lorenza

2017-05-01

Motivated by the challenge of seeking a rigorous foundation for the bulk-boundary correspondence for free fermions, we introduce an algorithm for determining exactly the spectrum and a generalized-eigenvector basis of a class of banded block quasi-Toeplitz matrices that we call corner-modified. Corner modifications of otherwise arbitrary banded block-Toeplitz matrices capture the effect of boundary conditions and the associated breakdown of translational invariance. Our algorithm leverages the interplay between a non-standard, projector-based method of kernel determination (physically, a bulk-boundary separation) and families of linear representations of the algebra of matrix Laurent polynomials. Thanks to the fact that these representations act on infinite-dimensional carrier spaces in which translation symmetry is restored, it becomes possible to determine the eigensystem of an auxiliary projected block-Laurent matrix. This results in an analytic eigenvector Ansatz, independent of the system size, which we prove is guaranteed to contain the full solution of the original finite-dimensional problem. The actual solution is then obtained by imposing compatibility with a boundary matrix, whose shape is also independent of system size. As an application, we show analytically that eigenvectors of short-ranged fermionic tight-binding models may display power-law corrections to exponential behavior, and demonstrate the phenomenon for the paradigmatic Majorana chain of Kitaev.

Hydrogeology and ground-water-flow simulation of the Cave Springs area, Hixson, Tennessee

USGS Publications Warehouse

Haugh, Connor J.

2002-01-01

The ground-water resource in the Cave Springs area is used by the Hixson Utility District as a water supply and is one of the more heavily stressed in the Valley and Ridge Physiographic Province. In 1999, ground-water withdrawals by the Hixson Utility District averaged about 6.4 million gallons per day (Mgal/d) from two pumping centers. The Hixson Utility District has historically withdrawn about 5.8 Mgal/d from wells at Cave Springs. In 1995 to meet increasing demand, an additional well field was developed at Walkers Corner, located about 3 miles northeast of Cave Springs. From 1995 through 2000, pumping from the first production well at Walkers Corner averaged about 1.8 Mgal/d. A second production well at Walkers Corner was approved for use in 2000. Hixson Utility District alternates the use of the two production wells at Walkers Corner except when drought conditions occur when they are used simultaneously. The second production well increased the capacity of the well field by an additional 2 Mgal/d. The aquifer framework in the study area consists of dense Paleozoic carbonate rocks with secondary permeability that are mantled by thick residual clay-rich regolith in most of the area and by coarse-grained alluvium in the valley of North Chickamauga Creek. Cave Springs, one of the largest springs in Tennessee, derives its flow from conduits in a carbonate rock (karst) aquifer. Production wells at Cave Springs draw water from these conduits. Production wells at Walkers Corner primarily draw water from gravel zones in the regolith near the top of rock. Transmissivities estimated from hydraulic tests conducted across the Cave Springs area span a range from 240 to 900,000 feet squared per day (ft2/d) with a median value of 5,200 ft2/d. Recharge to the aquifer occurs from direct infiltration of precipitation and from losing streams. Most recharge occurs during the winter and spring months. Computer modeling was used to provide a better understanding of the ground-water-flow system and to simulate the effects of additional ground-water withdrawals. A numerical ground-water-flow model of the ground-water system was constructed and calibrated using MODFLOW 2000. Modeling results indicate that losing streams along the base of the Cumberland Plateau escarpment at the western edge of the study area are an important source of recharge to the ground-water system, supplying about 50 percent of the recharge to the study area. Direct infiltration of precipitation accounts for the remaining recharge to the study area. In 1999, ground-water withdrawals of 6.4 Mgal/d [9.9 cubic feet per second (ft3/s)] equaled about 11 percent of the total simulated ground-water recharge. The remaining ground-water recharge discharges to rivers (48 percent, 41.1 ft3/s), springs (19 percent, 16.8 ft3/s), and Chickamauga Lake (22 percent, 19.0 ft3/s). Drawdown at the Walkers Corner well field in 2000 was about 33 feet at the center of a cone of depression that is elongated along strike. If additional pumping at Walkers Corner increases withdrawals by 2 Mgal/d, simulated drawdown at the Walkers Corner well field increases to about 60 feet and simulated ground-water discharges decrease by amounts of 1.0 ft3/s to Chickamauga Lake, 0.8 ft3/s to North Chickamauga Creek, 0.5 ft3/s to Lick Branch-Rogers Spring drainage, 0.5 ft3/s to Poe Branch, and 0.2 ft3/s to Cave Springs.

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

EDGE (Experiential Discoveries in Geoscience Education) Field Course Provides Alaskan High School and Middle School students with Earth Science and GIS Skills for Science Fair Projects and a College Experience

NASA Astrophysics Data System (ADS)

Connor, C. L.; Prakash, A.; Brownlee, M.; Nagorski, S.; Walling, R.

2006-12-01

For this outreach project we created watershed scale field activities in the Mendenhall Glacier system in Juneau, Alaska to introduce pre-college students to earth surface processes. These activities were designed to teach field data collection methods and to provide experiences that included exposure to the disciplines of glaciology, hydrology, and geomorphology. Students used their own observations to understand the on-going effects of warming climate in southeastern Alaska. Twenty seven, pre-college students from throughout the state participated in a 5-day, two-credit, introductory college-level course. This course was designed to introduce them to earth science as practiced in the field. Students divided their time between field sessions with data collection and indoor GIS labs. EDGE field excursions enabled students to learn about glacial geomorphology from river rafts, to collect stream discharge and other hydrologic data in local streams, and to integrate glacier recession observations with GPS waypoints collected from observed recessional positions. In labs at the University of Alaska Southeast campus, EDGE students were introduced to the fundamentals of ArcGIS. They downloaded their GPS waypoints onto modern and historic maps. They analyzed their stream flow data and created dynamic maps using their own observations in the field. During Fall 2006 semester, the students will generate earth science projects in their villages and towns that they can complete and present to their peers. EDGE teachers who attended a 10 day workshop in June will mentor their EDGE students. EDGE teachers and students will return to the UAS Juneau campus in March 2007 for a symposium. EGDE students will present their projects to Juneau area undergraduates and Juneau School District K-12 classes. In addition EDGE high school students will have the option to enter and compete in the Southeast Alaska Regional Science Fair held the same weekend. Funding from the National Science Foundation (NSF), US Department of Education, and NASA Space Grant programs will support 3-4 cohorts of EDGE teachers and 2-3 cohorts of EDGE students.

iMAST Quarterly, Number 4, 1999

DTIC Science & Technology

1999-01-01

ELEMENT NUMBER 6 . AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Penn State... 6 Calendar of Events .............................................. 8 Good-bye We are rapidly approaching the end of 1999 and...U.Ed. ARL 00- 6 DIRECTOR’S CORNER iMAST Quarterly 1999 No. 4 3 FEATURE ARTICLE Focus on Environmentally Friendly Technologies Automated Paint

Fiber-optics couple arthroscope to TV

NASA Technical Reports Server (NTRS)

Franke, J. M.; Rhodes, D. B.

1981-01-01

Convenient, hand-held coupler images output of arthroscope onto coherent fiber bundle. Arthroscope allows surgeons to examine internal organs through any small opening in body. Coupler is also used for engine inspection, instrument repair, and around-corner visual inspection. Image from arthroscope travels along flexible bundle and appears at other cable end where it is recollimated by lens. Image is read from lens or projected on color TV camera.

Physical Education "in All Sorts of Corners:" Student Activists Transgressing Formal Physical Education Curricular Boundaries

ERIC Educational Resources Information Center

Enright, Eimear; O'Sullivan, Mary

2012-01-01

The data for this paper were generated during a 3-year, participatory action research project, with 41 female coresearchers and activists ages 15-19 years old, within and beyond the walls of a secondary school. The two questions we sought to answer were (a) what happens when we engage with students to challenge formal physical education curricular…

JPRS Report, Nuclear Developments.

DTIC Science & Technology

1989-09-18

institution had strongly supported the project, which was proposed by experts from the Peruvian Nuclear Energy Institute (IPEN) with the cooperation of...the Science College of the National Engineering Univer- sity. The equipment was obtained under a Peruvian - Argentine agreement, [passage omitted...A football shaped thing was on a stand in the other corner. The official said that was the Islamic bomb and asked if we Pakistanis still denied

Consider outsourcing IT projects when cutting-edge technology, specialized focus are needed.

PubMed

1999-05-01

Looking outside to meet information technology needs proves a smart way to avert extra staffing costs. Kaiser Permanente saves thousands each year by contracting out cutting-edge IT projects instead of hiring more full-time staff it doesn't need. Learn how the organization incorporates outsourcing and other temporary work methods into its IT staffing strategy.

Quantification of local strain distributions in nanoscale strained SiGe FinFET structures

NASA Astrophysics Data System (ADS)

Mochizuki, Shogo; Murray, Conal E.; Madan, Anita; Pinto, Teresa; Wang, Yun-Yu; Li, Juntao; Weng, Weihao; Jagannathan, Hemanth; Imai, Yasuhiko; Kimura, Shigeru; Takeuchi, Shotaro; Sakai, Akira

2017-10-01

Strain within nanoscale strained SiGe FinFET structures has been investigated using a combination of X-ray diffraction and transmission electron microscopy-based nanobeam diffraction (NBD) techniques to reveal the evolution of the stress state within the FinFETs. Reciprocal space maps collected using high-resolution X-ray diffraction exhibited distinct features corresponding to the SiGe fin width, pitch, and lattice deformation and were analyzed to quantify the state of stress within the fins. Although the majority of the SiGe fin volume exhibited a uniaxial stress state due to elastic relaxation of the transverse in-plane stress, NBD measurements confirmed a small interaction region near the SOI interface that is mechanically constrained by the underlying substrate. We have quantitatively characterized the evolution of the fin stress state from biaxial to uniaxial as a function of fin aspect ratio and Ge fraction and confirmed that the fins obey elastic deformation based on a model that depends on the relative difference between the equilibrium Si and SiGe lattice constants and relative fraction of in-plane stress transverse to the SiGe fins. Spatially resolved, nanobeam X-ray diffraction measurements conducted near the SiGe fin edge indicate the presence of additional elastic relaxation from a uniaxial stress state to a fully relaxed state at the fin edge. Mapping of the lattice deformation within 500 nm of this fin edge by NBD revealed large gradients, particularly at the top corner of the fin. The values of the volume averaged lattice deformation obtained by nanoXRD and NBD are qualitatively consistent. Furthermore, the modulation of strain at the fin edge obtained by quantitative analysis of the nanoXRD results agrees with the lattice deformation profile obtained by NBD.

A{sub 5}RE{sub 4}X[TO{sub 4}]{sub 4} crystal growth: Fluoride flux synthesis of Na{sub 5}Ln{sub 4}F[GeO{sub 4}]{sub 4} (Ln=Pr, Nd), the first quaternary germanate oxyfluorides

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

Latshaw, Allison M.; Wilkins, Branford O.; Morrison, Gregory

Crystals of Na{sub 5}Pr{sub 4}F[GeO{sub 4}]{sub 4} and Na{sub 5}Nd{sub 4}F[GeO{sub 4}]{sub 4} were synthesized using a eutectic sodium fluoride, sodium chloride flux. Both compounds crystallize in the tetragonal space group I-4 with lattice parameters of a=12.1173(4) Å and c=5.6795(2) Å (Pr) and of a=12.0642(17) Å and c=5.6674(11) Å (Nd). The structure of the reported compounds is three-dimensional with face and corner sharing lanthanide polyhedra which edge and corner share with isolated germanium tetrahedra. These novel compositions represent the first example of quaternary germanium containing oxyfluorides. - Graphical abstract: Structural image of the first examples of quaternary germanate oxyfluorides. Displaymore » Omitted - Highlights: • Molten flux growth of crystals of two lanthanide germanate oxyfluorides. • Expansion of the A{sub 5}RE{sub 4}X[TO{sub 4}]{sub 4} family into germanate oxyfluorides. • Synthesis of Na{sub 5}Nd{sub 4}F[GeO{sub 4}]{sub 4} and Na{sub 5}Pr{sub 4}F[GeO{sub 4}]{sub 4}.« less

Na(7)Mg(13)Nd(PO(4))(12).

PubMed

Jerbi, Hasna; Hidouri, Mourad; Mongi, Ben Amara

2012-06-01

Investigations of the quasi-ternary system Na(3)PO(4)-Mg(3)(PO(4))(2)-NdPO(4) allowed us to obtain the new phosphate hepta-sodium trideca-magnesium neodymium dodeca-kis-phosphate, Na(7)Mg(13)Nd(PO(4))(12), by applying a flux method. The crystal structure is isotypic with that of the previously reported Na(7)Mg(13)Ln(PO(4))(12) (Ln = Eu, La) compounds. It consists of a complex three-dimensional framework built up from an NdO(8) polyhedron (m symmetry), an MO(6) octa-hedron statistically occupied by M = Mg and Na, and eight MgO(x) (x = 5, 6) polyhedra (four with site symmetry m), linked either directely by sharing corners, edges and faces, or by one of the eight unique PO(4) tetra-hedra through common corners. Two of the PO(4) tetra-hedra are statisticaly disordered over a mirror plane. The whole structure can be described as resutling from an assembly of two types of structural units, viz [Mg(4)MP(4)O(22)](∞) (2) layers extending parallel to (100) and stacked along [100], and [Mg(4)NdP(4)O(36)](∞) (1) undulating chains running along the [010] direction. The six different Na(+) cations (five with site symmetry m and one with 0.5 occupancy) are situated in six distinct cavities delimited by the framework. The structure was refined from data of a racemic twin.

An innovative small angle slot divertor concept for long pulse advanced tokamaks

NASA Astrophysics Data System (ADS)

Guo, Houyang

2017-10-01

A new Small Angle Slot (SAS) divertor is being developed in DIII-D to address the challenge of efficient divertor heat dispersal at the relatively low plasma density required for non-inductive current drive in future advanced tokamaks. SAS features a small incident angle near the plasma strike point on the divertor target plate with a progressively opening slot. SOLPS (B2-Eirene) edge code analysis finds that SAS can achieve strong plasma cooling when the strike point is placed near the small angle target plate in the slot, leading to low electron temperature Te across the entire divertor target. This is enabled by strong coupling between a gas tight slot and directed neutral recycling by the small angle target to enhance neutral buildup near the target. SOLPS analysis reveals a strong correlation between Te and D2 density at the target for various divertor configurations including the flat target, slanted target, and lower single null divertor. The strong correlation suggests that achievement of low Te may reduce essentially to identifying the divertor baffle geometry that achieves the highest target gas density at a given upstream condition. The SAS divertor concept has recently been tested in DIII-D for a range of plasma configurations and conditions with precise control of slot strike point location. In confirmation of SOLPS predictions, a sharp transition is observed when the strike point is moved to the critical outer corner of SAS. A set of Langmuir probes imbedded in SAS show that the Te radial profile, which is peaked at the strike point when it is located away from the SAS corner, becomes low across the target when the strike point is located near the corner. With further increase in density, deep-slot detachment occurs with Te 1 eV, measured by the unique DIII-D divertor Thomson Scattering diagnostic. Work supported by US DOE under DE-FC02-04ER54698.

YCrWO 6 : Polar and Magnetic Oxide with CaTa 2O 6 -Related Structure

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

Kim, Sun Woo; Emge, Thomas J.; Deng, Zheng

Here, a new polar and magnetic oxide, YCrWO 6, was successfully synthesized and characterized. YCrWO 6 crystallizes in polar orthorhombic space group Pna21 (no. 33) of edge-sharing dimers of CrO 6 and WO 6 octahedra, which are connected by corner-sharing to form a three-dimensional framework structure with Y 3+ cations located in the channels. The structure of YCrWO 6 is related to that of CaTa2O 6; however, the ordering of Cr 3+ and W 6+ in the octahedral sites breaks the inversion symmetry of the parent CaTa 2O 6 structure. X-ray absorption near edge spectroscopy of YCrWO 6 confirmed themore » oxidation state of Cr 3+ and W 6+. Temperature-dependent optical second harmonic generation measurements on YCrWO 6 confirmed the noncentrosymmetric character and evidenced a noncentrosymmetric-to-centrosymmetric phase transition above 800 °C. Piezoresponse force microscopy measurements on YCrWO 6 at room temperature show strong piezoelectric domains. Magnetic measurements of YCrWO 6 indicate antiferromagnetic order at T N of ~22 K with Weiss temperature of -34.66 K.« less

Shape-Dependent Electrocatalytic Reduction of CO2 to CO on Triangular Silver Nanoplates.

PubMed

Liu, Subiao; Tao, Hongbiao; Zeng, Li; Liu, Qi; Xu, Zhenghe; Liu, Qingxia; Luo, Jing-Li

2017-02-15

Electrochemical reduction of CO 2 (CO 2 RR) provides great potential for intermittent renewable energy storage. This study demonstrates a predominant shape-dependent electrocatalytic reduction of CO 2 to CO on triangular silver nanoplates (Tri-Ag-NPs) in 0.1 M KHCO 3 . Compared with similarly sized Ag nanoparticles (SS-Ag-NPs) and bulk Ag, Tri-Ag-NPs exhibited an enhanced current density and significantly improved Faradaic efficiency (96.8%) and energy efficiency (61.7%), together with a considerable durability (7 days). Additionally, CO starts to be observed at an ultralow overpotential of 96 mV, further confirming the superiority of Tri-Ag-NPs as a catalyst for CO 2 RR toward CO formation. Density functional theory calculations reveal that the significantly enhanced electrocatalytic activity and selectivity at lowered overpotential originate from the shape-controlled structure. This not only provides the optimum edge-to-corner ratio but also dominates at the facet of Ag(100) where it requires lower energy to initiate the rate-determining step. This study demonstrates a promising approach to tune electrocatalytic activity and selectivity of metal catalysts for CO 2 RR by creating optimal facet and edge site through shape-control synthesis.

Twin lead ballistic conductor based on nanoribbon edge transport

NASA Astrophysics Data System (ADS)

Konôpka, Martin; Dieška, Peter

2018-03-01

If a device like a graphene nanoribbon (GNR) has all its four corners attached to electric current leads, the device becomes a quantum junction through which two electrical circuits can interact. We study such system theoretically for stationary currents. The 4-point energy-dependent conductance matrix of the nanostructure and the classical resistors in the circuits are parameters of the model. The two bias voltages in the circuits are the control variables of the studied system while the electrochemical potentials at the device's terminals are non-trivially dependent on the voltages. For the special case of the linear-response regime analytical formulae for the operation of the coupled quantum-classical device are derived and applied. For higher bias voltages numerical solutions are obtained. The effects of non-equilibrium Fermi levels are captured using a recursive algorithm in which self-consistency between the electrochemical potentials and the currents is reached within few iterations. The developed approach allows to study scenarios ranging from independent circuits to strongly coupled ones. For the chosen model of the GNR with highly conductive zigzag edges we determine the regime in which the single device carries two almost independent currents.

Computer design synthesis of a below knee-Syme prosthesis

NASA Technical Reports Server (NTRS)

Elangovan, P. T.; Ghista, D. N.; Alwar, R. S.

1979-01-01

A detailed design synthesis analysis of the BK Syme prosthesis is provided, to determine the socket's cutout orientation size and shape, cutout fillet shape, socket wall thickness distribution and the reinforced fiber distribution in the socket wall, for a minimally stressed structurally safe lightweight prosthesis. For analysis purposes, the most adverse socket loading is obtained at the push-off stage of gait; this loading is idealized as an axial in-plane loading on the bottom edge of the circular cylindrical socket shell whose top edge is considered fixed. Finite element stress analysis of the socket shell (with uniform and graded wall thickness) are performed for various orientations of the cutout and for various types of corner fillets. A lateral cutout with a streamline fillet is recommended. The wall material (i.e., thickness) distribution is determined so as to minimize the stresses, while ensuring that the wall material's stress limits are not exceeded. For such a maximally stressed lightweight socket shell, the panels in the neighborhood of the cutout are checked to ensure that they do not buckle under their acquired stresses. A fiber-reinforced laminated composite socket shell is also analyzed in order to recommend optimum variables in orientations and densities of reinforcing fibers.

Image wavelet decomposition and applications

NASA Technical Reports Server (NTRS)

Treil, N.; Mallat, S.; Bajcsy, R.

1989-01-01

The general problem of computer vision has been investigated for more that 20 years and is still one of the most challenging fields in artificial intelligence. Indeed, taking a look at the human visual system can give us an idea of the complexity of any solution to the problem of visual recognition. This general task can be decomposed into a whole hierarchy of problems ranging from pixel processing to high level segmentation and complex objects recognition. Contrasting an image at different representations provides useful information such as edges. An example of low level signal and image processing using the theory of wavelets is introduced which provides the basis for multiresolution representation. Like the human brain, we use a multiorientation process which detects features independently in different orientation sectors. So, images of the same orientation but of different resolutions are contrasted to gather information about an image. An interesting image representation using energy zero crossings is developed. This representation is shown to be experimentally complete and leads to some higher level applications such as edge and corner finding, which in turn provides two basic steps to image segmentation. The possibilities of feedback between different levels of processing are also discussed.

YCrWO 6 : Polar and Magnetic Oxide with CaTa 2O 6 -Related Structure

DOE PAGES

Kim, Sun Woo; Emge, Thomas J.; Deng, Zheng; ...

2018-01-05

Here, a new polar and magnetic oxide, YCrWO 6, was successfully synthesized and characterized. YCrWO 6 crystallizes in polar orthorhombic space group Pna21 (no. 33) of edge-sharing dimers of CrO 6 and WO 6 octahedra, which are connected by corner-sharing to form a three-dimensional framework structure with Y 3+ cations located in the channels. The structure of YCrWO 6 is related to that of CaTa2O 6; however, the ordering of Cr 3+ and W 6+ in the octahedral sites breaks the inversion symmetry of the parent CaTa 2O 6 structure. X-ray absorption near edge spectroscopy of YCrWO 6 confirmed themore » oxidation state of Cr 3+ and W 6+. Temperature-dependent optical second harmonic generation measurements on YCrWO 6 confirmed the noncentrosymmetric character and evidenced a noncentrosymmetric-to-centrosymmetric phase transition above 800 °C. Piezoresponse force microscopy measurements on YCrWO 6 at room temperature show strong piezoelectric domains. Magnetic measurements of YCrWO 6 indicate antiferromagnetic order at T N of ~22 K with Weiss temperature of -34.66 K.« less

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.

Surface structure of micro-diamond from ultrahigh-pressure felsic granulite, Bohemian Massif: AFM study of growth and resorption phenomena

NASA Astrophysics Data System (ADS)

Kotková, J.; Klapetek, P.

2012-04-01

Morphology, associated phases and retrogression phenomena of in-situ microdiamonds formed at extreme pressures in ultrahigh-pressure metamorphic terranes represent excellent tools to study character of diamond-forming media at great depths. Well-preserved microdiamonds discovered recently along with coesite in ultrahigh-pressure granulites of the north Bohemian crystalline basement, European Variscan belt (Kotková et al., 2011), provide unique material for such investigations. The diamonds are enclosed in major granulite phases, i.e. garnet both in felsic and intermediate lithologies and in kyanite in the felsic sample, as well as in zircon. Transmitted and reflected light microscopy of the felsic granulite sample, with peak mineral assemblage garnet, kyanite, feldspar and quartz, revealed presence of numerous, 5-20 μm-sized, perfectly preserved diamond crystals enclosed in kyanite grains. In contrast, diamonds within garnet are rare, can reach up to 30 μm in size, and graphite rims as well as polycrystalline graphite aggregates possibly representing complete diamond retrogression are common. We applied atomic force microscopy to study in-situ crystal morphology and surface microtopographic features, representing clues to the conditions and mechanisms of crystal formation as well as diamond resorption and retrogression. Both diamond enclosed in garnet and in kyanite of the felsic granulite occur exclusively as single crystals. The crystals have octahedral crystal shapes with straight but rounded edges and rounded corners. Concentric triangular terraces delimiting a flat triangular table on crystal scale and small micron-sized negatively oriented downward-pointing trigons developed on the octahedron crystal faces. Higher magnification reveals presence of discontinuous elongate hillocks oriented parallel to the octahedron face edge with positively oriented trigons. We suggest that the large-scale triangular terraces represent growth features. In contrast, the rounding of crystal edges and corners and development of negative trigons reflect diamond resorption. According to experimental works, such features are attributed to high temperature resorption, i.e. oxidation above ~ 950°C due to interaction with CO2 and/or H2O-bearing fluids (or fluid-bearing melts). Our results are consistent with presence of supercritical C-O-H fluid in the rocks in subduction zones documented from other ultrahigh-pressure metamorphic terranes, the resorption morphology corresponding rather to the interaction with water-rich than CO2-rich fluids. Kotková J., ÓBrien P., Ziemann M. (2011): Diamond and coesite discovered in Saxony-type granulite: Solution to the Variscan garnet peridotite enigma. Geology, 39, 7, 667-670.

Structural alteration of hexagonal birnessite by aqueous Mn(II): Impacts on Ni(II) sorption

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

Lefkowitz, Joshua P.; Elzinga, Evert J.

We studied the impacts of aqueous Mn(II) (1 mM) on the sorption of Ni(II) (200 μM) by hexagonal birnessite (0.1 g L- 1) at pH 6.5 and 7.5 with batch experiments and XRD, ATR-FTIR and Ni K-edge EXAFS analyses. In the absence of Mn(II)aq, sorbed Ni(II) was coordinated predominantly as triple corner-sharing complexes at layer vacancies at both pH values. Introduction of Mn(II)aq into Ni(II)-birnessite suspensions at pH 6.5 caused Ni(II) desorption and led to the formation of edge-sharing Ni(II) complexes. This was attributed to competitive displacement of Ni(II) from layer vacancies by either Mn(II) or by Mn(III) formed throughmore » interfacial Mn(II)-Mn(IV) comproportionation, and/or incorporation of Ni(II) into the birnessite lattice promoted by Mn(II)-catalyzed recrystallization of the sorbent. Similar to Mn(II)aq, the presence of HEPES or MES caused the formation of edge-sharing Ni(II) sorption complexes in Ni(II)-birnessite suspensions, which was attributed to partial reduction of the sorbent by the buffers. At pH 7.5, interaction with aqueous Mn(II) caused reductive transformation of birnessite into secondary feitknechtite that incorporated Ni(II), enhancing removal of Ni(II) from solution. These results demonstrate that reductive alteration of phyllomanganates may significantly affect the speciation and solubility of Ni(II) in anoxic and suboxic environments.« less

Adaptive Gaze Strategies for Locomotion with Constricted Visual Field

PubMed Central

Authié, Colas N.; Berthoz, Alain; Sahel, José-Alain; Safran, Avinoam B.

2017-01-01

In retinitis pigmentosa (RP), loss of peripheral visual field accounts for most difficulties encountered in visuo-motor coordination during locomotion. The purpose of this study was to accurately assess the impact of peripheral visual field loss on gaze strategies during locomotion, and identify compensatory mechanisms. Nine RP subjects presenting a central visual field limited to 10–25° in diameter, and nine healthy subjects were asked to walk in one of three directions—straight ahead to a visual target, leftward and rightward through a door frame, with or without obstacle on the way. Whole body kinematics were recorded by motion capture, and gaze direction in space was reconstructed using an eye-tracker. Changes in gaze strategies were identified in RP subjects, including extensive exploration prior to walking, frequent fixations of the ground (even knowing no obstacle was present), of door edges, essentially of the proximal one, of obstacle edge/corner, and alternating door edges fixations when approaching the door. This was associated with more frequent, sometimes larger rapid-eye-movements, larger movements, and forward tilting of the head. Despite the visual handicap, the trajectory geometry was identical between groups, with a small decrease in walking speed in RPs. These findings identify the adaptive changes in sensory-motor coordination, in order to ensure visual awareness of the surrounding, detect changes in spatial configuration, collect information for self-motion, update the postural reference frame, and update egocentric distances to environmental objects. They are of crucial importance for the design of optimized rehabilitation procedures. PMID:28798674

Analyzing the effect of tool edge radius on cutting temperature in micro-milling process

NASA Astrophysics Data System (ADS)

Liang, Y. C.; Yang, K.; Zheng, K. N.; Bai, Q. S.; Chen, W. Q.; Sun, G. Y.

2010-10-01

Cutting heat is one of the important physical subjects in the cutting process. Cutting heat together with cutting temperature produced by the cutting process will directly have effects on the tool wear and the life as well as on the workpiece processing precision and surface quality. The feature size of the workpiece is usually several microns. Thus, the tiny changes of cutting temperature will affect the workpiece on the surface quality and accuracy. Therefore, cutting heat and temperature generated in micro-milling will have significantly different effect than the one in the traditional tools cutting. In this paper, a two-dimensional coupled thermal-mechanical finite element model is adopted to determine thermal fields and cutting temperature during the Micro-milling process, by using software Deform-2D. The effect of tool edge radius on effective stress, effective strain, velocity field and cutting temperature distribution in micro-milling of aluminum alloy Al2024-T6 were investigated and analyzed. Also, the transient cutting temperature distribution was simulated dynamically. The simulation results show that the cutting temperature in Micro-milling is lower than those occurring in conventional milling processes due to the small loads and low cutting velocity. With increase of tool edge radius, the maximum temperature region gradually occurs on the contact region between finished surfaced and flank face of micro-cutter, instead of the rake face or the corner of micro-cutter. And this phenomenon shows an obvious size effect.

Flow simulations on an organ pipe foot model.

PubMed

Vaik, István; Paál, György

2013-02-01

The present paper shows numerical simulations of the flow responsible for the sound generation in an organ pipe. Only the foot model of the organ pipe (i.e., with the resonator detached) is investigated by two-dimensional incompressible CFD simulations. It is shown that in spite of the moderately high Reynolds number (Re≈2350) no turbulence modeling is necessary. Free jet simulation (foot model without the upper lip) showed that the jet oscillates due to its natural instability. The velocity profile, the centerline and the width of the jet is determined at different heights above the flue. Edge tone simulations (foot model with the upper lip) were carried out having the upper lip at a constant height but at different x positions. It was found that the strongest and most stable edge tone oscillation occurs if the lower left corner of the upper lip is in the centerline of the jet (optimum position). When the upper lip is far from its optimum position the oscillation of the jet is rather due to the natural instability of the jet than the edge tone phenomenon. The results agree well with the experimental results of Außerlechner et al. [J. Acoust. Soc. Am. 126, 878-886 (2009)] and Außerlechner (Ph.D. thesis, Universität Stuttgart, Stuttgart, Germany) and with former results of the authors [Paál and Vaik, Int. J. Heat Fluid Flow 28, 575-586 (2007); Paál and Vaik, in Conference on Modelling Fluid Flow (CMFF'09), Budapest, Hungary].

Murzuk Sand Sea, Sahara Desert, Libya, Africa

NASA Image and Video Library

1993-01-19

STS054-152-189 (13-19 Jan. 1993) --- This near-vertical color photograph shows the very diverse landscape that is part of the great Sahara Desert of north Africa. Specifically, the vast expanse of sand dunes, located in the extreme southwestern corner of Libya, is known as the Murzuk Sand Sea. Close inspection of this photograph shows the agricultural village of Murzuk as evidenced by the numerous center pivot irrigation patterns at the edge of the Murzuk Sand Sea. The very rugged, dissected terrain to the west of this sand sea is the eastern tip of the Tassili N'ajjer Mountains and the Tadrart Plateau that are in neighboring Algeria. Several smaller areas of sand dunes are interspersed between the major areas of rock outcrops. The photograph was taken with a Linhof camera.

GEMINI-7 - EARTH-SKY VIEW - MIDDLE-EAST AREA - OUTER SPACE

NASA Image and Video Library

1965-12-08

S65-63849 (8 Dec. 1965) --- The eastern Mediterranean area as seen from the National Aeronautics and Space Administration's Gemini-7 spacecraft. The Nile Delta in Egypt is at bottom. The Suez Canal, Gulf of Suez and Red Sea are in the center of the photograph. The Sinai Peninsula is in the upper right corner of the picture. The body of water at the top edge of the photograph is the Gulf of Aqaba. The Dead Sea can be seen at top center. Israel, Palestine, Jordan and Syria are also at top center. The Island of Cyprus is at extreme left. Astronauts Frank Borman and James A. Lovell Jr. took this picture using a modified 70mm Hasselblad camera, with Eastman Kodak, Ektachrome MS (S.O. 217) color film. Photo credit: NASA

Linear fitting of multi-threshold counting data with a pixel-array detector for spectral X-ray imaging

PubMed Central

Muir, Ryan D.; Pogranichney, Nicholas R.; Muir, J. Lewis; Sullivan, Shane Z.; Battaile, Kevin P.; Mulichak, Anne M.; Toth, Scott J.; Keefe, Lisa J.; Simpson, Garth J.

2014-01-01

Experiments and modeling are described to perform spectral fitting of multi-threshold counting measurements on a pixel-array detector. An analytical model was developed for describing the probability density function of detected voltage in X-ray photon-counting arrays, utilizing fractional photon counting to account for edge/corner effects from voltage plumes that spread across multiple pixels. Each pixel was mathematically calibrated by fitting the detected voltage distributions to the model at both 13.5 keV and 15.0 keV X-ray energies. The model and established pixel responses were then exploited to statistically recover images of X-ray intensity as a function of X-ray energy in a simulated multi-wavelength and multi-counting threshold experiment. PMID:25178010

Linear fitting of multi-threshold counting data with a pixel-array detector for spectral X-ray imaging.

PubMed

Muir, Ryan D; Pogranichney, Nicholas R; Muir, J Lewis; Sullivan, Shane Z; Battaile, Kevin P; Mulichak, Anne M; Toth, Scott J; Keefe, Lisa J; Simpson, Garth J

2014-09-01

Experiments and modeling are described to perform spectral fitting of multi-threshold counting measurements on a pixel-array detector. An analytical model was developed for describing the probability density function of detected voltage in X-ray photon-counting arrays, utilizing fractional photon counting to account for edge/corner effects from voltage plumes that spread across multiple pixels. Each pixel was mathematically calibrated by fitting the detected voltage distributions to the model at both 13.5 keV and 15.0 keV X-ray energies. The model and established pixel responses were then exploited to statistically recover images of X-ray intensity as a function of X-ray energy in a simulated multi-wavelength and multi-counting threshold experiment.

Floquet high Chern insulators in periodically driven chirally stacked multilayer graphene

NASA Astrophysics Data System (ADS)

Li, Si; Liu, Cheng-Cheng; Yao, Yugui

2018-03-01

Chirally stacked N-layer graphene is a semimetal with ±p N band-touching at two nonequivalent corners in its Brillioun zone. We predict that an off-resonant circularly polarized light (CPL) drives chirally stacked N-layer graphene into a Floquet Chern insulators (FCIs), aka quantum anomalous Hall insulators, with tunable high Chern number C F = ±N and large gaps. A topological phase transition between such a FCI and a valley Hall (VH) insulator with high valley Chern number C v = ±N induced by a voltage gate can be engineered by the parameters of the CPL and voltage gate. We propose a topological domain wall between the FCI and VH phases, along which perfectly valley-polarized N-channel edge states propagate unidirectionally without backscattering.

The structural and magnetic phase transitions in Ca 0.73La 0.27FeAs 2 with electron overdoped FeAs layers.

DOE PAGES

Jiang, Shan; Liu, Chang; Cao, H.; ...

2016-02-26

Here we report a study of the Ca 0.73La 0.27FeAs 2 single crystals. We unravel a monoclinic to triclinic phase transition at 58 K, and a paramagnetic to stripe antiferromagnetic (AFM) phase transition at 54 K, below which spins order 45° away from the stripe direction. Furthermore, we demonstrate this material is substantially structurally untwinned at ambient pressure with the formation of spin rotation walls (S-walls). Finally, in addition to the central-hole and corner-electron Fermi pockets usually appearing in FPS, angle-resolved photoemission (ARPES) measurements resolve a Fermiology where an extra electron pocket of mainly As chain character exists at themore » Brillouin zone edge.« less

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.

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.

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...

ALMA from the Users' Perspective

NASA Astrophysics Data System (ADS)

Johnson, Kelsey

2010-05-01

After decades of dreaming and preparation, the call for early science with ALMA is just around the corner. The goal of this talk is to illustrate the process of preparing and carrying out a research program with ALMA. This presentation will step through the user interface for proposal preparation, proposal review, project tracking, data acquisition, and post-processing. Examples of the software tools, including the simulator and spectral line catalog, will be included.

Cycle/Cocycle Oblique Projections on Oriented Graphs

NASA Astrophysics Data System (ADS)

Polettini, Matteo

2015-01-01

It is well known that the edge vector space of an oriented graph can be decomposed in terms of cycles and cocycles (alias cuts, or bonds), and that a basis for the cycle and the cocycle spaces can be generated by adding and removing edges to an arbitrarily chosen spanning tree. In this paper, we show that the edge vector space can also be decomposed in terms of cycles and the generating edges of cocycles (called cochords), or of cocycles and the generating edges of cycles (called chords). From this observation follows a construction in terms of oblique complementary projection operators. We employ this algebraic construction to prove several properties of unweighted Kirchhoff-Symanzik matrices, encoding the mutual superposition between cycles and cocycles. In particular, we prove that dual matrices of planar graphs have the same spectrum (up to multiplicities). We briefly comment on how this construction provides a refined formalization of Kirchhoff's mesh analysis of electrical circuits, which has lately been applied to generic thermodynamic networks.

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.

National Uranium Resource Evaluation Program. Hydrogeochemical and stream sediment reconnaissance basic data for Beeville NTMS Quadrangle, Texas. Uranium resource evaluation project

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

Not Available

Results of a reconnaissance geochemical survey of the Beeville Quadrangle, Texas are reported. Field and laboratory data are presented for 373 groundwater and 364 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are displayed. A generalized geologic map of the survey area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. The groundwater data indicate that the northwestern corner of the quadrangle is the most favorable for potential uranium mineralization. Favorability is indicated by high uranium concentrations; high arsenic, molybdenum, and vanadium concentrations;more » and proximity and similar geologic setting to the mines of the Karnes County mining district. Other areas that appear favorable are an area in Bee and Refugio Counties and the northeastern part of the quadrangle. Both areas have water chemistry similar to the Karnes County area, but the northeastern area does not have high concentrations of pathfinder elements. The stream sediment data indicate that the northeastern corner of the quadrangle is the most favorable for potential mineralization, but agricultural practices and mineralogy of the outcropping Beaumont Formation may indicate a false anomaly. The northwestern corner of the quadrangle is considered favorable because of its proximity to the known uranium deposits, but the data do not seem to support this.« less

Automatic Edging and Trimming of Hardwood Lumber

Treesearch

D. Earl Kline; Eugene M. Wengert; Philip A. Araman

1990-01-01

Studies have shown that there is a potential to increase hardwood lumber value by more than 20 percent through optimum edging and trimming. Even a small portion of this percentage can boost the profitability of hardwood lumber manufacturers substantially. The objective of this research project is to develop an automated system which would assist in correct edging and...

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.

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

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.

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.

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." 

New HErschel Multi-wavelength Extragalactic Survey of Edge-on Spirals (NHEMESES)

NASA Astrophysics Data System (ADS)

Holwerda, B. W.; Bianchi, S.; Baes, M.; de Jong, R. S.; Dalcanton, J. J.; Radburn-Smith, D.; Gordon, K.; Xilouris, M.

2012-08-01

Edge-on spiral galaxies offer a unique perspective on the vertical structure of spiral disks, both stars and the iconic dark dustlanes. The thickness of these dustlanes can now be resolved for the first time with Herschel in far-infrared and sub-mm emission. We present NHEMESES, an ongoing project that targets 12 edge-on spiral galaxies with the PACS and SPIRE instruments on Herschel. These vertically resolved observations of edge-on spirals will impact on several current topics. First and foremost, these Herschel observations will settle whether or not there is a phase change in the vertical structure of the ISM with disk mass. Previously, a dramatic change in dustlane morphology was observed as in massive disks the dust collapses into a thin lane. If this is the case, the vertical balance between turbulence and gravity dictates the ISM structure and consequently star-formation and related phenomena (spiral arms, bars etc.). We specifically target lower mass nearby edge-ons to complement existing Herschel observations of high-mass edge-on spirals (the HEROES project). Secondly, the combined data-set, together with existing Spitzer observations, will drive a new generation of spiral disk Spectral Energy Distribution models. These model how dust reprocesses starlight to thermal emission but the dust geometry remains the critical unknown. And thirdly, the observations will provide an accurate and unbiased census of the cold dusty structures occasionally seen extending out of the plane of the disk, when backlit by the stellar disk. To illustrate the NHEMESES project, we present early results on NGC 4244 and NGC 891, two well studies examples of a low and high-mass edge-on spiral.

Pavement edge treatment.

DOT National Transportation Integrated Search

2013-01-01

Four projects were built over two construction seasons using special devices attached to the paving machine that produces a 30 slope on the outside pavement edge instead of the near vertical drop-off common with conventional paving equipment. This ...

Electron-beam lithography with character projection technique for high-throughput exposure with line-edge quality control

NASA Astrophysics Data System (ADS)

Ikeno, Rimon; Maruyama, Satoshi; Mita, Yoshio; Ikeda, Makoto; Asada, Kunihiro

2016-07-01

The high throughput of character projection (CP) electron-beam (EB) lithography makes it a promising technique for low-to-medium volume device fabrication with regularly arranged layouts, such as for standard-cell logics and memory arrays. However, non-VLSI applications such as MEMS and MOEMS may not be able to fully utilize the benefits of the CP method due to the wide variety of layout figures including curved and oblique edges. In addition, the stepwise shapes that appear because of the EB exposure process often result in intolerable edge roughness, which degrades device performances. In this study, we propose a general EB lithography methodology for such applications utilizing a combination of the CP and variable-shaped beam methods. In the process of layout data conversion with CP character instantiation, several control parameters were optimized to minimize the shot count, improve the edge quality, and enhance the overall device performance. We have demonstrated EB shot reduction and edge-quality improvement with our methodology by using a leading-edge EB exposure tool, ADVANTEST F7000S-VD02, and a high-resolution hydrogen silsesquioxane resist. Atomic force microscope observations were used to analyze the resist edge profiles' quality to determine the influence of the control parameters used in the data conversion process.

Line-edge quality optimization of electron beam resist for high-throughput character projection exposure utilizing atomic force microscope analysis

NASA Astrophysics Data System (ADS)

Ikeno, Rimon; Mita, Yoshio; Asada, Kunihiro

2017-04-01

High-throughput electron-beam lithography (EBL) by character projection (CP) and variable-shaped beam (VSB) methods is a promising technique for low-to-medium volume device fabrication with regularly arranged layouts, such as standard-cell logics and memory arrays. However, non-VLSI applications like MEMS and MOEMS may not fully utilize the benefits of CP method due to their wide variety of layout figures including curved and oblique edges. In addition, the stepwise shapes that appear on such irregular edges by VSB exposure often result in intolerable edge roughness, which may degrade performances of the fabricated devices. In our former study, we proposed a general EBL methodology for such applications utilizing a combination of CP and VSB methods, and demonstrated its capabilities in electron beam (EB) shot reduction and edge-quality improvement by using a leading-edge EB exposure tool, ADVANTEST F7000S-VD02, and high-resolution Hydrogen Silsesquioxane resist. Both scanning electron microscope and atomic force microscope observations were used to analyze quality of the resist edge profiles to determine the influence of the control parameters used in the exposure-data preparation process. In this study, we carried out detailed analysis of the captured edge profiles utilizing Fourier analysis, and successfully distinguish the systematic undulation by the exposed CP character profiles from random roughness components. Such capability of precise edge-roughness analysis is useful to our EBL methodology to maintain both the line-edge quality and the exposure throughput by optimizing the control parameters in the layout data conversion.

SKYLAB III - POSTLAUNCH (JOKE)

NASA Image and Video Library

1973-09-25

S73-34456 (September 1973) --- Flight Director Neil B. Hutchinson, left, and astronaut Bruce McCandless II hold up a glass enclosure - home for the spider Arachne, which is the same species as the two spiders carried on the Skylab 3 mission. The real spider is the one barely visible at the upper right corner of the square; the larger one is a projected image on the rear-screen-projected map in the front of the Mission Operations Control Room (MOCR) of the Mission Control Center (MCC). McCandless served as backup pilot for the first manned Skylab mission and was a spacecraft communicater (CAPCOM) for the second crew. Photo credit: NASA

Personnel in Mission Control examine replica of spider habitat from Skylab 3

NASA Technical Reports Server (NTRS)

1973-01-01

Flight Director Neil B. Hutchinson, left, and Astronaut Bruce McCandless II hold up a glass enclosure - home for the spider Arachne, which is the same species as the two spiders carried on the Skylab 3 mission. The real spider is the one barely visible at the upper right corner of the square; the larger one is a projected image on the rear-screen-projected map in the front of the Mission Operations Control Room (MOCR) of the Mission Control Center (MCC). McCandless served as backup pilot for the first manned Skylab mission and was a spacecraft-communicater (CAPCOM) for the second crew.

Sociable Machines: Expressive Social Exchange between Humans and Robots

DTIC Science & Technology

2000-05-01

many occasions about theories on emotion. I’ve cornered Robert Irie’s again and again about auditory processing. I’ve bugged Matto Marjanovic throughout...development at the MIT Artificial Intel- ligence Lab (Brooks, Breazeal, Marjanovic , Scassellati & Williamson 1999). Cog is a general purpose humanoid...RA-2, 253-262. Brooks, R. A., Breazeal, C., Marjanovic , M., Scassellati, B. & Williamson, M. M. (1999), The Cog Project: Building a Humanoid Robot, in

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.

Potential environmental effects of the leading edge hydrokinetic energy technology.

DOT National Transportation Integrated Search

2017-05-01

The Volpe Center evaluated potential environmental challenges and benefits of the ARPA-E funded research project, Marine Hydrokinetic Energy Harvesting Using Cyber-Physical Systems, led by Brown University. The Leading Edge research team develo...

5. Long view from canyon edge, west of the overlook, ...

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

5. Long view from canyon edge, west of the overlook, showing relationship of Mather Point to neighboring south rim projections; view to southeast - Mather Point Overlook, South Entrance Road, Grand Canyon Village, Coconino County, AZ

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.

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.

Experimental investigation of the cornering characteristics of 18 by 5.5, type 7, aircraft tires with different tread patterns

NASA Technical Reports Server (NTRS)

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

1974-01-01

The characteristics, which include the cornering-force and drag-force friction coefficients and self-alining torque, were obtained on dry, damp, and flooded runway surfaces over a range of yaw angles from 0 deg to 12 deg and at ground speeds from approximately 5 to 90 knots. The results indicate that a tread pattern with pinholes in the ribs reduces the tire cornering capability at high yaw angles on a damp surface but improves cornering on a dry surface. A tread pattern which has transverse grooves across the entire width of the tread improves the tire cornering performance slightly at high speeds on the flooded runway surface. The cornering capability of all the tires is degraded at high ground speeds by thin film lubrication and/or tire hydroplaning effects. Alterations to the conventional tread pattern provide only marginal improvements in the tire cornering capability which suggests that runway surface treatments may be a more effective way of improving aircraft ground performance during wet operations.

Observation of Phase Objects by Using an X-ray Microscope with a Foucault Knife-Edge

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

Watanabe, N.; Sasaya, T.; Imai, Y.

2011-09-09

An x-ray microscope with a zone plate was assembled at the synchrotron radiation source of BL3C, Photon Factory. A Foucault knife-edge was set at the back focal plate of the objective zone plate and phase retrieval was tested by scanning the knife-edge. A preliminary result shows that scanning the knife-edge during exposure was effective for phase retrieval. Phase-contrast tomography was investigated using differential projection images calculated from two Schlieren images with the oppositely oriented knife-edges. Fairly good reconstruction images of polystyrene beads and spores could be obtained.

Development Challenges of Utilizing a Corner Cube Mechanism Design with Successful IASI Flight Heritage for the Infrared Sounder (IRS) on MTG: Recurrent Mechanical Design not Correlated to Recurrent Development

NASA Astrophysics Data System (ADS)

Spanoudakis, Peter; Schwab, Philippe; Kiener, Lionel; Saudan, Herve; Perruchoud, Gerald

2015-09-01

The Corner Cube Mechanism (CCM) design for the Infra-Red Sounder (IRS) on MTG is based on the successful mechanism currently in orbit on the Infrared Atmospheric Sounding Interferometers (IASI) on the Metop satellites. The overall CCM performance is described with attention given to the specific design developments for the MTG project. A description is presented of the modifications introduced and challenges encountered to adapt the IASI space heritage design (which is only 15 years old) to meet the MTG specifications. A detailed account is provided regarding the tests performed on the adapted components for the new programme. The major issues encountered and solutions proposed are illustrated concerning the voice- coil actuator development, optical switch design, fatigue life of the flexure components and the adaptation of the launch locking device. Nevertheless, an Engineering Qualification Model was rapidly manufactured and now undergoing a qualification test campaign.

Experimental study of the heated contact line region for a pure fluid and binary fluid mixture in microgravity.

PubMed

Nguyen, Thao T T; Kundan, Akshay; Wayner, Peter C; Plawsky, Joel L; Chao, David F; Sicker, Ronald J

2017-02-15

Understanding the dynamics of phase change heat and mass transfer in the three-phase contact line region is a critical step toward improving the efficiency of phase change processes. Phase change becomes especially complicated when a fluid mixture is used. In this paper, a wickless heat pipe was operated on the International Space Station (ISS) to study the contact line dynamics of a pentane/isohexane mixture. Different interfacial regions were identified, compared, and studied. Using high resolution (50×), interference images, we calculated the curvature gradient of the liquid-vapor interface at the contact line region along the edges of the heat pipe. We found that the curvature gradient in the evaporation region increases with increasing heat flux magnitude and decreasing pentane concentration. The curvature gradient for the mixture case is larger than for the pure pentane case. The difference between the two cases increases as pentane concentration decreases. Our data showed that the curvature gradient profile within the evaporation section is separated into two regions with the boundary between the two corresponding to the location of a thick, liquid, "central drop" region at the point of maximum internal local heat flux. We found that the curvature gradients at the central drop and on the flat surfaces where condensation begins are one order of magnitude smaller than the gradients in the corner meniscus indicating the driving forces for fluid flow are much larger in the corners. Copyright © 2016 Elsevier Inc. All rights reserved.

Finite Source Inversion for Laboratory Earthquakes

NASA Astrophysics Data System (ADS)

Parker, J. M.; Glaser, S. D.

2017-12-01

We produce finite source inversion results for laboratory earthquakes (LEQ) in PMMA confirmed by video recording of the fault contact. The LEQs are generated under highly controlled laboratory conditions and recorded by an array of absolutely calibrated acoustic emissions (AE) sensors. Following the method of Hartzell and Heaton (1983), we develop a solution using only the single-component AE sensors common in laboratory experiments. A set of calibration tests using glass capillary sources of varying size resolves the material characteristics and synthetic Green's Functions such that uncertainty in source location is reduced to 3σ<1mm; typical source radii are 1mm. Well-isolated events with corner frequencies on the order of 0.1 MHz (Mw -6) are recorded at 20 MHz and initially band-pass filtered from 0.1 to 1.0 MHz; in comparison, large earthquakes with corner frequencies around 0.1 Hz are commonly filtered from 0.1 to 1.0 Hz. We compare results of the inversion and video recording to slip distribution predicted by the Cattaneo partial slip asperity and numerical modeling. Not all asperities are large enough to resolve individually so some results must be interpreted as the smoothed effects of clusters of tiny contacts. For large asperities, partial slip is observed originating at the asperity edges and moving inward as predicted by the theory. Furthermore, expanding shear rupture fronts are observed as they reach resistive patches of asperities and halt or continue, depending on the relative energies of rupture and resistance.

Geologic map of the Jam Up Cave and Pine Crest quadrangles, Shannon, Texas, and Howell Counties, Missouri

USGS Publications Warehouse

Weary, David J.; Orndorff, Randall C.; Repetski, John E.

2013-01-01

The Jam Up Cave and Pine Crest 7.5-minute quadrangles are located in south-central Missouri within the Salem Plateau region of the Ozark Plateaus physiographic province. About 2,400 to 3,100 feet (ft) of flat-lying to gently dipping Lower Paleozoic sedimentary rocks, mostly dolomite, chert, sandstone, and orthoquartzite, overlie Mesoproterozoic igneous basement rocks. Unconsolidated residuum, colluvium, terrace deposits, and alluvium overlie the sedimentary rocks. Numerous karst features, such as sinkholes, caves, and springs, have formed in the carbonate rocks. Many streams are spring fed. The topography is a dissected karst plain with elevations ranging from about 690 ft where the Jacks Fork River exits the northeastern corner of the Jam Up Cave quadrangle to about 1,350 ft in upland areas along the north-central edge and southwestern corner of the Pine Crest quadrangle. The most prominent physiographic feature is the valley of the Jacks Fork River. This reach of the upper Jacks Fork, with its clean, swiftly-flowing water confined by low cliffs and bluffs, provides one of the most beautiful canoe float trips in the nation. Most of the land in the quadrangles is privately owned and used primarily for grazing cattle and horses and growing timber. A large minority of the land within the quadrangles is publicly owned by the Ozark National Scenic Riverways of the National Park Service. Geologic mapping for this investigation was conducted in 2005 and 2006.

Aerodynamic analysis of seamless horizontal stabilizer

NASA Astrophysics Data System (ADS)

Nithya, S.; Kanimozhi, S.

2017-05-01

This project presents an investigative view into the concept of seamless aeroelastic wing and hingeless flexible trailing edge. Wings are designed to provide maximum lift and minimal drag and weight. But with conventional wings where rivets are used and the control surfaces are separately hinged, parasite drag comes into play. This project is about analysing a smooth seamless wing with hinge-less flexible trailing edge. This type of wing reduces the drag considerably and the hinge-less trailing edge leads to a minimal control demand and reduces the noise produced when the aircraft comes for landing. Seamless aeroelastic wing will function as an integrated one piece lifting and control surface. It has been designed to enhance a desirable wing camber for control by deflecting a hinge-less flexible trailing edge part instead of a traditional hinged control surface. This kind of flexible wing can be achieved either by a curved beam and disc actuation mechanism or by piezo-electric materials, whose shape change can be achieved by electricity. The intent of this project is to analyze the effects of introducing the concept of Seamless Wing to the horizontal stabilizer. While the removal of rivets and serrations that hinge the elevators to the stabilizer reduces the overall drag by a reasonable value, the overall concept of a control surface-less stabilizer where the maneuvers are done by deflecting the trailing edge offers better maneuverability.

Li0.5Al0.5Mg2(MoO4)3

PubMed Central

Ennajeh, Ines; Zid, Mohamed Faouzi; Driss, Ahmed

2013-01-01

The title compound, lithium/aluminium dimagnesium tetra­kis­[orthomolybdate(VI)], was prepared by a solid-state reaction route. The crystal structure is built up from MgO6 octa­hedra and MoO4 tetra­hedra sharing corners and edges, forming two types of chains running along [100]. These chains are linked into layers parallel to (010) and finally linked by MoO4 tetra­hedra into a three-dimensional framework structure with channels parallel to [001] in which lithium and aluminium cations equally occupy the same position within a distorted trigonal–bipyramidal coordination environment. The title structure is isotypic with LiMgIn(MoO4)3, with the In site becoming an Mg site and the fully occupied Li site a statistically occupied Li/Al site in the title structure. PMID:24426975

Nonlinear regimes on polygonal hydraulic jumps

NASA Astrophysics Data System (ADS)

Rojas, Nicolas

2016-11-01

This work extends previous leading and higher order results on the polygonal hydraulic jump in the framework of inertial lubrication theory. The rotation of steady polygonal jumps is observed in the transition from one wavenumber to the next one, induced by a change in height of an external obstacle near the outer edge. In a previous publication, the study of stationary polygons is considered under the assumption that the reference frame rotates with the polygons when the number of corners change, in order to preserve their orientation. In this research work I provide a Hamiltonian approach and the stability analysis of the nonlinear oscillator that describe the polygonal structures at the jump interface, in addition to a perturbation method that enables to explain, for instance, the diversity of patterns found in experiments. GRASP, Institute of Physics, University of Liege, Belgium.

Redetermination of AgPO(3).

PubMed

Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

2011-02-09

Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure.

TURKEY-EARTH RESOURCES (MT.ARARAT)

NASA Image and Video Library

2013-10-28

SL3-122-2562 (July-September 1973) --- A near vertical view of the border area of Turkey-Iran?Union of Soviet Socialist Republics as seen from the Skylab space station in Earth orbit. This picture was taken by one of the Skylab 3 crewmen using a hand-held 70mm Hasselblad camera. THE PICTURE SHOULD BE HELD WITH THE MASS OF WHITE CLOUDS ON THE RIGHT SIDE. The lake at the top center edge is Ozero (Lake) Sevan in the USSR?s Armenian Soviet Socialist Republic. The other body of water is Iran?s Lake Urmia. The major feature in this photograph can be seen in the upper left corner. Mount Ararat is in Turkey only a few miles from Iran and USSR borders. Yerevan, the capital of Armenian SSR, is located north-northwest of Mount Ararat. Photo credit: NASA

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.

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

Forests on the Edge: A GIS-based Approach to Projecting Housing Development on Private Forests

Treesearch

Ron McRoberts; Mark Nelson; David Theobald; Mike Eley; Mike Dechter

2006-01-01

The private working land base of America’s forests, farms, and ranches is being converted at the rate of nearly 1,620 ha (4,000 acres) per day with tremendous economic, ecological, and social impacts. The United States Department of Agriculture (USDA) Forest Service is sponsoring the “Forests on the Edge” project to develop a better understanding of the contributions...

Internal and external axial corner flows

NASA Technical Reports Server (NTRS)

Kutler, P.; Shankar, V.; Anderson, D. A.; Sorenson, R. L.

1975-01-01

The inviscid, internal, and external axial corner flows generated by two intersecting wedges traveling supersonically are obtained by use of a second-order shock-capturing, finite-difference approach. The governing equations are solved iteratively in conical coordinates to yield the complicated wave structure of the internal corner and the simple peripheral shock of the external corner. The numerical results for the internal flows compare favorably with existing experimental data.

Pilot Construction Project for Granular Shoulder Stabilization

DOT National Transportation Integrated Search

2013-09-30

Granular shoulders need to be maintained on a regular basis because edge ruts and potholes develop, posing a safety hazard to motorists. The successful mitigation of edge-rut issues for granular shoulders would increase safety and reduce the number o...

Evolution of supersonic corner vortex in a hypersonic inlet/isolator model

NASA Astrophysics Data System (ADS)

Huang, He-Xia; Tan, Hui-Jun; Sun, Shu; Ling, Yu

2016-12-01

There are complex corner vortex flows in a rectangular hypersonic inlet/isolator. The corner vortex propagates downstream and interacts with the shocks and expansion waves in the isolator repeatedly. The supersonic corner vortex in a generic hypersonic inlet/isolator model is theoretically and numerically analyzed at a freestream Mach number of 4.92. The cross-flow topology of the corner vortex flow is found to obey Zhang's theory ["Analytical analysis of subsonic and supersonic vortex formation," Acta Aerodyn. Sin. 13, 259-264 (1995)] strictly, except for the short process with the vortex core situated in a subsonic flow which is surrounded by a supersonic flow. In general, the evolution history of the corner vortex under the influence of the background waves in the hypersonic inlet/isolator model can be classified into two types, namely, from the adverse pressure gradient region to the favorable pressure gradient region and the reversed one. For type 1, the corner vortex is a one-celled vortex with the cross-sectional streamlines spiraling inwards at first. Then the Hopf bifurcation occurs and the streamlines in the outer part of the limit cycle switch to spiraling outwards, yielding a two-celled vortex. The limit cycle shrinks gradually and finally vanishes with the streamlines of the entire corner vortex spiraling outwards. For type 2, the cross-sectional streamlines of the corner vortex spiral outwards first. Then a stable limit cycle is formed, yielding a two-celled vortex. The short-lived limit cycle forces the streamlines in the corner vortex to change the spiraling trends rapidly. Although it is found in this paper that there are some defects on the theoretical proof of the limit cycle, Zhang's theory is proven useful for the prediction and qualitative analysis of the complex corner vortex in a hypersonic inlet/isolator. In addition, three conservation laws inside the limit cycle are obtained.

A fast method to emulate an iterative POCS image reconstruction algorithm.

PubMed

Zeng, Gengsheng L

2017-10-01

Iterative image reconstruction algorithms are commonly used to optimize an objective function, especially when the objective function is nonquadratic. Generally speaking, the iterative algorithms are computationally inefficient. This paper presents a fast algorithm that has one backprojection and no forward projection. This paper derives a new method to solve an optimization problem. The nonquadratic constraint, for example, an edge-preserving denoising constraint is implemented as a nonlinear filter. The algorithm is derived based on the POCS (projections onto projections onto convex sets) approach. A windowed FBP (filtered backprojection) algorithm enforces the data fidelity. An iterative procedure, divided into segments, enforces edge-enhancement denoising. Each segment performs nonlinear filtering. The derived iterative algorithm is computationally efficient. It contains only one backprojection and no forward projection. Low-dose CT data are used for algorithm feasibility studies. The nonlinearity is implemented as an edge-enhancing noise-smoothing filter. The patient studies results demonstrate its effectiveness in processing low-dose x ray CT data. This fast algorithm can be used to replace many iterative algorithms. © 2017 American Association of Physicists in Medicine.

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

Electron-beam lithography with character projection exposure for throughput enhancement with line-edge quality optimization

NASA Astrophysics Data System (ADS)

Ikeno, Rimon; Maruyama, Satoshi; Mita, Yoshio; Ikeda, Makoto; Asada, Kunihiro

2016-03-01

Among various electron-beam lithography (EBL) techniques, variable-shaped beam (VSB) and character projection (CP) methods have attracted many EBL users for their high-throughput feature, but they are considered to be more suited to small-featured VLSI fabrication with regularly-arranged layouts like standard-cell logics and memory arrays. On the other hand, non-VLSI applications like photonics, MEMS, MOEMS, and so on, have not been fully utilized the benefit of CP method due to their wide variety of layout patterns. In addition, the stepwise edge shapes by VSB method often causes intolerable edge roughness to degrade device characteristics from its intended performance with smooth edges. We proposed an overall EBL methodology applicable to wade-variety of EBL applications utilizing VSB and CP methods. Its key idea is in our layout data conversion algorithm that decomposes curved or oblique edges of arbitrary layout patterns into CP shots. We expect significant reduction in EB shot count with a CP-bordered exposure data compared to the corresponding VSB-alone conversion result. Several CP conversion parameters are used to optimize EB exposure throughput, edge quality, and resultant device characteristics. We demonstrated out methodology using the leading-edge VSB/CP EBL tool, ADVANTEST F7000S-VD02, with high resolution Hydrogen Silsesquioxane (HSQ) resist. Through our experiments of curved and oblique edge lithography under various data conversion conditions, we learned correspondence of the conversion parameters to the resultant edge roughness and other conditions. They will be utilized as the fundamental data for further enhancement of our EBL strategy for optimized EB exposure.

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.

Crustal structure across the lateral edge of the Southern Tyrrhenian slab

NASA Astrophysics Data System (ADS)

Pio Lucente, Francesco; Piana Agostinetti, Nicola; Di Bona, Massimo; Govoni, Aladino; Bianchi, Irene

2015-04-01

In the southeastern corner of the Tyrrhenian basin, in the central Mediterranean Sea, a tight alignment of earthquakes along a well-defined Benioff zone reveals the presence of one of the narrowest active trenches worldwide, where one of the last fragments of the former Tethys ocean is consumed. Seismic tomography furnishes snapshot images of the present-day position and shape of this slab. Through receiver function analysis we investigate the layered structures overlying the slab. We compute receiver functions from the P-coda of teleseismic events at 13 temporary station deployed during the "Messina 1908-2008" research project (Margheriti, 2008), and operating for an average period of 15 months each. The crustal and uppermost mantle structure has been investigated using a trans-dimensional McMC algorithm developed by Piana Agostinetti and Malinverno (2010), obtaining a 1D S-wave velocity profile for each station. At three of the stations, operating for a longer period of time, the number and the azimuthal distribution of teleseisms allowed us to stack the RF data-set with back azimuth and to compute the harmonic expansion. The analysis of the back-azimuthal harmonics gave us insight on the presence of dipping interfaces and anisotropic layers at depth. The strike and the dip of interfaces and the anisotropic parameters have been quantified using the Neighbourhood Algorithm (Sambridge, 1999). Preliminary results highlight: (1) a neat differentiation of the isotropic S-wave velocity structure passing through the slab edge, from the tip of the Calabrian arc to the Peloritani Range, and (2) the presence of crustal complexities, such as dipping interfaces and anisotropic layers, both in the upper and lower crust. Margheriti, L. (2008), Understanding Crust Dynamics and Subduction in Southern Italy, Eos Trans. AGU, 89(25), 225-226, doi:10.1029/2008EO250002. Piana Agostinetti, N. and A. Malinverno (2010) Receiver Function inversion by trans-dimensional Monte Carlo sampling, Geophys. J. Int., 181(2) 858-872, doi: 10.1111/j.1365-246X.2010.04530.x Sambridge, M. (1999), Geophysical inversion with a neighbourhood algorithm-I. Searching a parameter space, Geophys. J. Int., 138, 479-494, doi:10.1046/j.1365-246X.1999.00876.x.

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

DSMC computations of hypersonic flow separation and re-attachment in the transition to continuum regime

NASA Astrophysics Data System (ADS)

Prakash, Ram; Gai, Sudhir L.; O'Byrne, Sean; Brown, Melrose

2016-11-01

The flow over a `tick' shaped configuration is performed using two Direct Simulation Monte Carlo codes: the DS2V code of Bird and the code from Sandia National Laboratory, called SPARTA. The configuration creates a flow field, where the flow is expanded initially but then is affected by the adverse pressure gradient induced by a compression surface. The flow field is challenging in the sense that the full flow domain is comprised of localized areas spanning continuum and transitional regimes. The present work focuses on the capability of SPARTA to model such flow conditions and also towards a comparative evaluation with results from DS2V. An extensive grid adaptation study is performed using both the codes on a model with a sharp leading edge and the converged results are then compared. The computational predictions are evaluated in terms of surface parameters such as heat flux, shear stress, pressure and velocity slip. SPARTA consistently predicts higher values for these surface properties. The skin friction predictions of both the codes don't give any indication of separation but the velocity slip plots indicate an incipient separation behavior at the corner. The differences in the results are attributed towards the flow resolution at the leading edge that dictates the downstream flow characteristics.

Nanopore fabricated in pyramidal HfO2 film by dielectric breakdown method

NASA Astrophysics Data System (ADS)

Wang, Yifan; Chen, Qi; Deng, Tao; Liu, Zewen

2017-10-01

The dielectric breakdown method provides an innovative solution to fabricate solid-state nanopores on insulating films. A nanopore generation event via this method is considered to be caused by random charged traps (i.e., structural defects) and high electric fields in the membrane. Thus, the position and number of nanopores on planar films prepared by the dielectric breakdown method is hard to control. In this paper, we propose to fabricate nanopores on pyramidal HfO2 films (10-nm and 15-nm-thick) to improve the ability to control the location and number during the fabrication process. Since the electric field intensity gets enhanced at the corners of the pyramid-shaped film, the probability of nanopore occurrence at vertex and edge areas increases. This priority of appearance provides us chance to control the location and number of nanopores by monitoring a sudden irreversible discrete increase in current. The experimental results showed that the probability of nanopore occurrence decreases in an order from the vertex area, the edge area to the side face area. The sizes of nanopores ranging from 30 nm to 10 nm were obtained. Nanopores fabricated on the pyramid-shaped HfO2 film also showed an obvious ion current rectification characteristic, which might improve the nanopore performance as a biomolecule sequencing platform.

Origins of Moiré Patterns in CVD-grown MoS2 Bilayer Structures at the Atomic Scales.

PubMed

Wang, Jin; Namburu, Raju; Dubey, Madan; Dongare, Avinash M

2018-06-21

The chemical vapor deposition (CVD)-grown two-dimensional molybdenum disulfide (MoS 2 ) structures comprise of flakes of few layers with different dimensions. The top layers are relatively smaller in size than the bottom layers, resulting in the formation of edges/steps across adjacent layers. The strain response of such few-layer terraced structures is therefore likely to be different from exfoliated few-layered structures with similar dimensions without any terraces. In this study, the strain response of CVD-grown few-layered MoS 2 terraced structures is investigated at the atomic scales using classic molecular dynamics (MD) simulations. MD simulations suggest that the strain relaxation of CVD-grown triangular terraced structures is observed in the vertical displacement of the atoms across the layers that results in the formation of Moiré patterns. The Moiré islands are observed to nucleate at the corners or edges of the few-layered structure and propagate inwards under both tensile and compressive strains. The nucleation of these islands is observed to happen at tensile strains of ~ 2% and at compressive strains of ~2.5%. The vertical displacements of the atoms and the dimensions of the Moiré islands predicted using the MD simulation are in excellent agreement with that observed experimentally.

A Possible Role for End-Stopped V1 Neurons in the Perception of Motion: A Computational Model

PubMed Central

Zarei Eskikand, Parvin; Kameneva, Tatiana; Ibbotson, Michael R.; Burkitt, Anthony N.; Grayden, David B.

2016-01-01

We present a model of the early stages of processing in the visual cortex, in particular V1 and MT, to investigate the potential role of end-stopped V1 neurons in solving the aperture problem. A hierarchical network is used in which the incoming motion signals provided by complex V1 neurons and end-stopped V1 neurons proceed to MT neurons at the next stage. MT neurons are categorized into two types based on their function: integration and segmentation. The role of integration neurons is to propagate unambiguous motion signals arriving from those V1 neurons that emphasize object terminators (e.g. corners). Segmentation neurons detect the discontinuities in the input stimulus to control the activity of integration neurons. Although the activity of the complex V1 neurons at the terminators of the object accurately represents the direction of the motion, their level of activity is less than the activity of the neurons along the edges. Therefore, a model incorporating end-stopped neurons is essential to suppress ambiguous motion signals along the edges of the stimulus. It is shown that the unambiguous motion signals at terminators propagate over the rest of the object to achieve an accurate representation of motion. PMID:27741307

First characterization of a digital SiPM based time-of-flight PET detector with 1 mm spatial resolution

NASA Astrophysics Data System (ADS)

Seifert, Stefan; van der Lei, Gerben; van Dam, Herman T.; Schaart, Dennis R.

2013-05-01

Monolithic scintillator detectors can offer a combination of spatial resolution, energy resolution, timing performance, depth-of-interaction information, and detection efficiency that make this type of detector a promising candidate for application in clinical, time-of-flight (TOF) positron emission tomography (PET). In such detectors the scintillation light is distributed over a relatively large number of photosensor pixels and the light intensity per pixel can be relatively low. Therefore, monolithic scintillator detectors are expected to benefit from the low readout noise offered by a novel photosensor called the digital silicon photomultiplier (dSiPM). Here, we present a first experimental characterization of a TOF PET detector comprising a 24 × 24 × 10 mm3 LSO:Ce,0.2%Ca scintillator read out by a dSiPM array (DPC-6400-44-22) developed by Philips Digital Photon Counting. A spatial resolution of ˜1 mm full-width-at-half-maximum (FWHM) averaged over the entire crystal was obtained (varying from just below 1 mm FWHM in the detector center to ˜1.2 mm FWHM close to the edges). Furthermore, the bias in the position estimation at the crystal edges that is typically found in monolithic scintillators is well below 1 mm even in the corners of the crystal.

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.

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.

Aerial gamma ray and magnetic survey: Powder River R and D Project, Arminto Detail, Wyoming. Final report

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

Not Available

1979-05-01

The small detail area, 18 miles by 18 miles, lying near the center of the Powder River Basin, is covered entirely by sediments of the Eocene Wasatch Formation. Historically economic uranium deposits have been worked in the southeast corner of the area which includes the northern extremity of the Pumpkin Buttes district. 127 statistical uranium anomalies were generated for the study area, based on area wide statistics.

KSC-04pd0651

NASA Image and Video Library

2004-03-26

KENNEDY SPACE CENTER, FLA. -- This aerial photo shows the storage area containing Launch Umbilical Towers that were used during the early years of the Space Program. In the lower left corner of the storage field is a Caterpillar excavator with a 48-inch shear demolishing LUT-1, used to launch Apollo 8, Apollo 11, Skylab manned missions and the Apollo-Soyuz Test Project. The shear is one used in the deconstruction of the Twin Towers in New York City after 9/11.

KSC-04pd0649

NASA Image and Video Library

2004-03-26

KENNEDY SPACE CENTER, FLA. -- This aerial photo shows the storage area containing Launch Umbilical Towers that were used during the early years of the Space Program. In the lower right corner of the storage field is a Caterpillar excavator with a 48-inch shear demolishing LUT-1, used to launch Apollo 8, Apollo 11, Skylab manned missions and the Apollo-Soyuz Test Project. The shear is one used in the deconstruction of the Twin Towers in New York City after 9/11.

KSC-04pd0648

NASA Image and Video Library

2004-03-26

KENNEDY SPACE CENTER, FLA. -- This aerial photo shows the storage area containing Launch Umbilical Towers that were used during the early years of the Space Program. In the upper right corner of the storage field is a Caterpillar excavator with a 48-inch shear demolishing LUT-1, used to launch Apollo 8, Apollo 11, Skylab manned missions and the Apollo-Soyuz Test Project. The shear is one used in the deconstruction of the Twin Towers in New York City after 9/11.

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

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.

Geologic map of the Valle 30' x 60' quadrangle, Coconino County, northern Arizona

USGS Publications Warehouse

Billingsley, George H.; Felger, Tracey J.; Priest, Susan S.

2006-01-01

The geologic map of the Valle 30' x 60' quadrangle is the result of a cooperative effort between the U.S. Geological Survey and the National Park Service to provide geologic information for regional resource management and visitor information services for Grand Canyon National Park, Arizona. The map area encompasses approximately 1,960 sq.mi. within Coconino County, northern Arizona and is bounded by long 112 deg to 113 deg W. and lat 35 deg 30 min to 36 deg N. and lies within the southern Colorado Plateaus geologic province (herein Colorado Plateau). The map area is locally subdivided into four physiographic parts; (1) the Grand Canyon (Cataract Canyon and extreme northeast corner of the map area), (2) the Coconino Plateau, (3) the Mount Floyd Volcanic Field, and (4) the San Francisco Volcanic Field as defined by Billingsley and others, 1997. Elevations range from 7,460 ft (2,274 m) on the Coconino Plateau along State Highway 64 northeast corner of the map area, to about 4,200 ft (1,280 m) at the bottom of Cataract Canyon. Settlements within the map area include Tusayan and Valle, Arizona. State Highway 64 and U.S. Highway 180 provide access to the Tusayan and Valle areas. Indian Route 18 is a paved highway in the northwest corner of the map area that is maintained by the Hualapai and Havasupai Indian Tribes and leads from State Route 66 about 7 mi (11 km) east of Peach Springs, Arizona to Hualapai Hilltop, a parking lot just north of the map area at the rim of Cataract Canyon where visitors begin an 8 mi (13 km) hike into Havasupai, Arizona. Other remote parts of the map are accessed by two dirt roads, which are maintained by Coconino County, and by several unmaintained local ranch roads. Weather conditions restrict travel within the area and visitors must obtain permission to access a few local ranch lands in the south-central edge of the map area. Extra water and food are highly recommended when traveling in this remote region. Access into Cataract Canyon is restricted to horse or foot travel and visitors must obtain permission from the Havasupai Tribe to hike within the Havasupai Indian Reservation. In the central part of the map area, most of the land is privately owned and managed by the Babbitt Ranches Inc. in conjunction with the Nature Conservancy and the Navajo Tribe. In the southern half of the map, land alternates between privately owned land and State land forming a checkerboard pattern. The National Park Service manages land in Grand Canyon National Park (extreme northeast edge of map area), the U.S. Forest Service manages lands in the Kaibab National Forest, the Hualapai Tribe manages lands in the northwest quarter of the map area, and the Havasupai Tribe manages lands within Cataract Canyon and adjacent parts of the Coconino Plateau.

Research in VLSI Systems. Heuristic Programming Project and VLSI Theory Project. A Fast Turn Around Facility for Very Large Scale Integration (VLSI)

DTIC Science & Technology

1982-11-01

to occur). When a rectangle is inserted, all currently selected items are de -selected, and the newly inserted rectangle is selected. This makes it...Items are de - * selected before the selection takes place. A selected symbol instance is displayed with a bold outline, and a selected rectangle edge...symbol instance or set of rectangle edges, everything previously selected is first de -selected. If the selected object is a reference point the old

Development of a community-sensitive strategy to increase availability of fresh fruits and vegetables in Nashville's urban food deserts, 2010-2012.

PubMed

Larson, Celia; Haushalter, Alisa; Buck, Tracy; Campbell, David; Henderson, Trevor; Schlundt, David

2013-07-25

Food deserts, areas that lack full-service grocery stores, may contribute to rising rates of obesity and chronic diseases among low-income and racial/ethnic minority residents. Our corner store project, part of the Centers for Disease Control and Prevention's Communities Putting Prevention to Work initiative, aimed to increase availability of healthful foods in food deserts in Nashville, Tennessee. We identified 4 food deserts in which most residents are low-income and racially and ethnically diverse. Our objectives were to develop an approach to increase availability of fresh fruits and vegetables, low-fat or nonfat milk, and 100% whole-wheat bread in Nashville's food deserts and to engage community members to inform our strategy. Five corner stores located in food deserts met inclusion criteria for our intervention. We then conducted community listening sessions, proprietor surveys, store audits, and customer-intercept surveys to identify needs, challenges to retailing the products, and potential intervention strategies. Few stores offered fresh fruits, fresh vegetables, low-fat or nonfat milk, or 100% whole-wheat bread, and none stocked items from all 4 categories. Major barriers to retailing healthful options identified by community members are mistrust of store owners, history of poor-quality produce, and limited familiarity with healthful options. Store owners identified neighborhood crime as the major barrier. We used community input to develop strategies. Engaging community residents and understanding neighborhood context is critical to developing strategies that increase access to healthful foods in corner stores.

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.

Geology of the State of Morelos and contiguous areas in south-central Mexico

USGS Publications Warehouse

Fries, Carl F.

1959-01-01

The area described lies in south-central Mexico and embraces all but the southeastern corner and easternmost border of the State of Moreles, the second smallest State in the Mexican Republic. It includes small contiguous parts of the State of Mexico, in the northeastern corner, and of the State of Guerrero in the southwestern corner. Limiting geographic coordinates are 98 45 to 99 39 west longitude and 18 18 to 19 08 north latitude, the northern boundary being only 35 km south of Mexico City, capital of the Republic. The geological map does not cover the entire rectangle outlined, but is irregular in form and measures roughly 4150 sq. km, three-quarters of it representing two0thirds of the State of Moreles and the rest lying outside the State. The region ranges in altitude from 730 m above sea level at Iguala near the south edge of the map, to a general level of about 3000 m at the north edge, although individual peaks rise to 3900 m and Popocatepetl Volcano, a few kilometers east of the northeastern border of the map, rises to 5452 m above sea level. Annual rainfall ranges from a minimum of about 640 mm in the low country, to 1200 mm and more at altitudes above 2000 m. Most of it falls in summer between June and September. Winter frosts are rare below 1800 m. The climate is of savanna to steppe type; soils are thin and may be classified as belonging to the tachernoses group, with strong development of calcareous evaporates (caliche) at altitudes below 1800 m. The northern border of the area forms the southern half of the late Pliocene to Recent Neo-volcanic Belt of basic volcanism that crosses Mexico in the direction N. 80 W., and thus has constructional topography. The rest of the area belongs to the Balsas Basin physiographic province, which is characterized by maturely dissected terrain tributary to the large Balsas River. All but the southwestern corner of the area drains southward via the Amacuzac River into the Mexcala-Balsas River, and thence westward into the Pacific Ocean. The southwestern corner drains directly into the Balsas River via the Iguala River. Local relief is of the order of 300 to 600 m. The mature topography was partly buried by late Pliocene alluvium in the central part of the area, owing largely to local volcanism. Dissolution of limestone, dolomite, and anhydrite of the Cretaceous formations has produced sinks and poljes, some of which contain small lakes. Other karst features are also common, such as caves, caverns, underground rivers, and surficial lapies or karren. Drainage blocking by lava and polje development in late Pleistocene and Recent time produced new alluvial flats in this otherwise dissected region. The oldest rock unit in the region is the Texco schist series of late Paleozoic (?) age. It was folded, metamorphosed, foliated, intruded by dikes, and strongly eroded before the next unit, the Texco Viejo green volcanic series of Late Triassic (?) age, was deposited. Another period of metamorphism and erosion followed before the calcareous clastic sediments of the Upper Jurassic (?) Acahuizotla formation were laid down. The next unit consists of the partly phyllitic calcareous shale of the Acuitlapan formation, which is of Neocenian (?) age and rests with at least disconformity on the Acahuizotla formation. The overlying Aptian-Barresian Kochicalco formation of thin-bedded limestone appears to grade upward from the Acuitlapan formation, locally, but it seems to be unconformable elsewhere. All these units have small outcrops in the area mapped and were not studied in detail. Warping and erosion occurred before the overlying Morelos formation began to accumulate in early Albian time. The basal member is anhydrite in the eastern part of the area mapped, but limestone and dolomite were deposited elsewhere. The formation consists largely of shallow-water calcareous bank deposits, with a maximum thickness of about 900 m. Deposition ceased in early Cenomanian time and further warpi

NCMS ESS 2000 Project

NASA Technical Reports Server (NTRS)

Gibbel, Mark; Bellamy, Marvin; DeSantis, Charlie; Hess, John; Pattok, Tracy; Quintero, Andrew; Silver, R.

1996-01-01

ESS 2000 has the vision of enhancing the knowledge necessary to implement cost-effective, leading-edge ESS technologies and procedures in order to increase U.S. electronics industry competitiveness. This paper defines EES and discusses the factors driving the project, the objectives of the project, its participants, the three phases of the project, the technologies involved, and project deliverables.

Creativity of Student Information System Projects: From the Perspective of Network Embeddedness

ERIC Educational Resources Information Center

Yang, Heng-Li; Cheng, Hsiu-Hua

2010-01-01

Many companies have pursued innovation to obtain a competitive edge. Thus, educational reform focuses mainly on training creative students. This study adopted the concept of an affiliated network of projects to investigate how project embeddedness influences project team creativity. This work surveys 60 projects in a Management Information Systems…

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.

Computer simulation of CaSiO3 glass under compression: correlation between Si-Si pair radial distribution function and intermediate range order structure

NASA Astrophysics Data System (ADS)

Lan, Mai Thi; Thuy Duong, Tran; Iitaka, Toshiaki; Van Hong, Nguyen

2017-06-01

The structural organization of CaSiO3 glass at 600 K and under pressure of 0-100 GPa is investigated by molecular dynamics simulation (MDS). Results show that the atomic structure of CaSiO3 comprises SiO n and CaO m units considered as basic structural polyhedra. At low pressure, most of the basic structural polyhedra are SiO4, CaO5, CaO6 and CaO7. At high pressure most of the basic structural polyhedra are SiO5, SiO6 and CaO9, CaO10 and CaO11. The distribution of basic structural polyhedra is not uniform resulting in formation of Ca-rich and Si-rich regions. The distribution of SiO4, SiO5 and SiO6 polyhedra is also not uniform, but it tends to form SiO4-, SiO5-, and SiO6-clusters. For the Si-O network, under compression there is a gradual transition from the tetrahedral network (SiO4) to the octahedral network (SiO6) via SiO5 polyhedra. The SiO5-clusters are the same as immediate-phase in the transformation process. The size and shape of SiO4 tetrahedra change strongly under compression. While the size of SiO5 and SiO6 has also changed significantly, but the shape is almost unchanged under compression. The SiO n polyhedra can connect to each other via one common oxygen ion (corner-sharing bond), two common oxygen ions (edge-sharing bond) or three common oxygen ions (face-sharing bond). The Si-Si bond length in corner-sharing bonds is much longer than the ones in edge-sharing and face-sharing bonds. The change of intermediate range order (IRO) structure under compression relating to edge- and face-sharing bonds amongst SiO n at high pressure is the origin of the first peak splitting of the radial distribution functions of Si-Si pair. Under compression, the number of non-bridging oxygen (NBO) decreases. This makes the Si-O network more polymerized. At low pressure, most of the Ca2+ ions incorporate into the Si-O network via NBOs. At high pressure, the amount of NBO decreases, Ca2+ ions mainly incorporate into the Si-O network via bridging oxygen (BO) that belongs to SiO5 and SiO6 with a negative charge. And this is the principle for immobilization of heavy metal as well as fissile materials in hazardous waste (nuclear waste).

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 & ...

STS-57 Earth observation of the Eastern Mediterranean, Nile River, Asia Minor

NASA Image and Video Library

1993-07-01

STS057-73-075 (21 June-1 July 1993) --- Eastern Mediterranean from an unusually high vantage point over the Nile River, this north-looking view shows not only the eastern Mediterranean but also the entire landmass of Asia Minor, with the Black Sea dimly visible at the horizon. Many of the Greek islands can be seen in the Aegean Sea (top left), off the coast of Asia Minor. Cyprus is visible under atmospheric dust in the northeast corner of the Mediterranean. The dust cloud covers the east end of the Mediterranean, its western edge demarcated by a line that cuts the center of the Nile Delta. This dust cloud originated far to the west, in Algeria, and moved northeast over Sicily, southern Italy, and Greece. Part of the cloud then moved on over the Black Sea, but another part swerved southward back towards Egypt. A gyre of clouds in the southeast corner of the Mediterranean indicates a complementary counterclockwise (cyclonic) circulation of air. The Euphrates River appears as a thin green line (upper right) in the yellow Syrian Desert just south of the blue-green mountains of Turkey. The Dead Sea (lower right) lies in a rift valley which extends north into Turkey and south thousands of miles down the Gulf of Aqaba, the Red Sea, and on through East Africa. The straight international boundary between Israel and Egypt (where the coastline angles) is particularly clear in this view, marked by the thicker vegetation on the Israeli side of the border. The green delta of the Nile River appears in the foreground, with the great conurbation of Cairo seen as a gray area at the apex of the triangle. Most of Egypt's 52 million inhabitants live in the delta. On the east side of the delta, the Suez Canal is visible. On the western corner of the delta lies the ancient city of Alexandria, beside the orange and white salt pans. The World War II battlesite El Alamein lies on the coast.

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.

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.

Subduction and Plate Edge Tectonics in the Southern Caribbean

NASA Astrophysics Data System (ADS)

Levander, A.; Schmitz, M.; Niu, F.; Bezada, M. J.; Miller, M. S.; Masy, J.; Ave Lallemant, H. G.; Pindell, J. L.

2012-12-01

The southern Caribbean plate boundary consists of a subduction zone at at either end connected by a strike-slip fault system: In the east at the Lesser Antilles subduction zone, the Atlantic part of the South American plate subducts beneath the Caribbean. In the north and west in the Colombia basin, the Caribbean subducts under South America. In a manner of speaking, the two plates subduct beneath each other. Finite-frequency teleseismic P-wave tomography confirms this, imaging the Atlantic and the Caribbean subducting steeply in opposite directions to transition zone depths under northern South America (Bezada et al, 2010). The two subduction zones are connected by the El Pilar-San Sebastian strike-slip fault system, a San Andreas scale system that has been cut off at the Bocono fault, the southeastern boundary of the Maracaibo block. A variety of seismic probes identify where the two plates tear as they begin to subduct (Niu et al, 2007; Clark et al., 2008; Miller et al. 2009; Growdon et al., 2009; Huang et al., 2010; Masy et al., 2011). The El Pilar system forms at the southeastern corner of the Antilles subduction zone with the Atlantic plate tearing from South America. The deforming plate edges control mountain building and basin formation at the eastern end of the strike-slip system. In northwestern South America the Caribbean plate very likely also tears, as its southernmost element subducts at shallow angles under northernmost Colombia and the northern, nonsubducting part underthrusts the continental edge. The subducting segment rapidly descends to transition zone depths under Lake Maracaibo (Bezada et al., 2010). We believe that the flat slab produces the Merida Andes, the Perija, and the Santa Marta ranges. The nonsubducting part of the Caribbean plate underthrusts northern Venezuela to about the width of the coastal mountains (Miller et al., 2009), where the plate edge supports the coastal mountains, and controls continuing deformation.

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

Mercury: Photomosaic of the Shakespeare Quadrangle (Northern Half) H-3

NASA Technical Reports Server (NTRS)

1974-01-01

This computer generated photomosaic from Mariner 10 is of the northern half of Mercury's Shakespeare Quadrangle, named for the ancient Shakespeare crater located on the lower edge to the left of center. This portion of the quadrangle covers the geographic region from 45 to 70 degrees north latitude and from 90 to 180 degrees longitude. The photomosaic was produced using computer techniques and software developed in the Image Processing Laboratory of NASA's Jet Propulsion Laboratory. The pictures have been high-pass filtered and contrast enhanced to accentuate surface detail, and geometrically transformed into a Lambert conformal projection.

The illuminated surface observed by Mariner 10 as it first approached Mercury is dominated by craters and basins. In marked contrast to this view, the surface photographed after the flyby exhibited features totally different, including large basins and extensive relatively smooth areas with few craters. The most striking feature in this region of the planet is a huge circular basin, 1300 kilometers in diameter, that was undoubtedly produced from a tremendous impact comparable to the event that formed the Imbrium basin on the Moon. This prominent Mercurian structure in the Shakespeare and Tolstoj quadrangles (lower left corner of this image), named Caloris Planitia, is filled with material forming a smooth surface or plain that appears similar in many respects to the lunar maria.

The above material was taken from the following publication... Davies, M. E., S. E. Dwornik, D. E. Gault, and R. G. Strom, Atlas of Mercury, NASA SP-423 (1978).

The Mariner 10 mission was managed by the Jet Propulsion Laboratory for NASA's Office of Space Science.

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

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.

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.

STS-31 crew activity on the middeck of the Earth-orbiting Discovery, OV-103

NASA Image and Video Library

1990-04-29

STS031-05-002 (24-29 April 1990) --- A 35mm camera with a "fish eye" lens captured this high angle image on Discovery's middeck. Astronaut Kathryn D. Sullivan works with the IMAX camera in foreground, while Astronaut Steven A. Hawley consults a checklist in corner. An Arriflex motion picture camera records student ion arc experiment in apparatus mounted on stowage locker. The experiment was the project of Gregory S. Peterson, currently a student at Utah State University.

Precision annotation of predetermined primary sampling units on ERTS-1 MSS images

NASA Technical Reports Server (NTRS)

Vanroessel, J. W.; Langley, P. G.

1973-01-01

Resectioning programs were developed for projecting the boundary corners of sample units, management units, and counties into U2 RC-10 and ERTS-1 MSS images. The technique used includes corrections for earth curvature, terrain elevation, and MSS distortions. The minimum standard error obtained was about 0.15 mm or 150 meters on the ground. This technique now makes it possible to include land ownership as an integral part of forest resource sampling plans using ERTS imagery.

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

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

First results of geodetic deformation monitoring after commencement of CO2 injection at the Aquistore underground CO2 storage site

NASA Astrophysics Data System (ADS)

Craymer, M.; White, D.; Piraszewski, M.; Zhao, Y.; Henton, J.; Silliker, J.; Samsonov, S.

2015-12-01

Aquistore is a demonstration project for the underground storage of CO2 at a depth of ~3350 m near Estevan, Saskatchewan, Canada. An objective of the project is to design, adapt, and test non-seismic monitoring methods that have not been systematically utilized to date for monitoring CO2 storage projects, and to integrate the data from these various monitoring tools to obtain quantitative estimates of the change in subsurface fluid distributions, pressure changes and associated surface deformation. Monitoring methods being applied include satellite-, surface- and wellbore-based monitoring systems and comprise natural- and controlled-source electromagnetic methods, gravity monitoring, continuous GPS, synthetic aperture radar interferometry (InSAR), tiltmeter array analysis, and chemical tracer studies. Here we focus on the GPS, InSAR and gravity monitoring. Five monitoring sites were installed in 2012 and another six in 2013, each including GPS and InSAR corner reflector monuments (some collocated on the same monument). The continuous GPS data from these stations have been processed on a daily basis in both baseline processing mode using the Bernese GPS Software and precise point positioning mode using CSRS-PPP. Gravity measurements at each site have also been performed in fall 2013, spring 2014 and fall 2015, and at two sites in fall 2014. InSAR measurements of deformation have been obtained for a 5 m footprint at each site as well as at the corner reflector point sources. Here we present the first results of this geodetic deformation monitoring after commencement of CO2 injection on April 14, 2015. The time series of these sites are examined, compared and analyzed with respect to monument stability, seasonal signals, longer term trends, and any changes in motion and mass since CO2 injection.

Simulation of Sentinel-2A Red Edge Bands with RPAS Based Multispectral Data

NASA Astrophysics Data System (ADS)

Davids, Corine; Storvold, Rune; Haarpaintner, Jorg; Arnason, Kolbeinn

2016-08-01

Very high spatial and spectral resolution multispectral data was collected over the Hallormstađur test site in eastern Iceland using a fixed wing remotely piloted aerial system as part of the EU FP7 project North State (www.northstatefp7.eu). The North State project uses forest variable estimates derived from optical and radar satellite data as either input or validation for carbon flux models. The RPAS data from the Hallormsstađur forest test site in Iceland is here used to simulate Landsat and Sentinel-2A data and to explore the advantages of the new Sentinel-2A red edge bands for forest vegetation mapping. Simple supervised classification shows that the inclusion of the red edge bands improves the tree species classification considerably.

Wigner crystalline edges in ν<~1 quantum dots

NASA Astrophysics Data System (ADS)

Goldmann, Eyal; Renn, Scot R.

1999-12-01

We investigate the edge reconstruction phenomenon believed to occur in quantum dots in the quantum Hall regime when the filling fraction is ν<~1. Our approach involves the examination of large dots (<= 40 electrons) using a partial diagonalization technique in which the occupancies of the deep interior orbitals are frozen. To interpret the results of this calculation, we evaluate the overlap between the diagonalized ground state and a set of trial wave functions which we call projected necklace (PN) states. A PN state is simply the angular momentum projection of a maximum density droplet surrounded by a ring of localized electrons. Our calculations reveal that PN states have up to 99% overlap with the diagonalized ground states, and are lower in energy than the states identified in Chamon and Wen's study of the edge reconstruction.

A Motion-Based Feature for Event-Based Pattern Recognition

PubMed Central

Clady, Xavier; Maro, Jean-Matthieu; Barré, Sébastien; Benosman, Ryad B.

2017-01-01

This paper introduces an event-based luminance-free feature from the output of asynchronous event-based neuromorphic retinas. The feature consists in mapping the distribution of the optical flow along the contours of the moving objects in the visual scene into a matrix. Asynchronous event-based neuromorphic retinas are composed of autonomous pixels, each of them asynchronously generating “spiking” events that encode relative changes in pixels' illumination at high temporal resolutions. The optical flow is computed at each event, and is integrated locally or globally in a speed and direction coordinate frame based grid, using speed-tuned temporal kernels. The latter ensures that the resulting feature equitably represents the distribution of the normal motion along the current moving edges, whatever their respective dynamics. The usefulness and the generality of the proposed feature are demonstrated in pattern recognition applications: local corner detection and global gesture recognition. PMID:28101001

Applying Workspace Limitations in a Velocity-Controlled Robotic Mechanism

NASA Technical Reports Server (NTRS)

Abdallah, Muhammad E. (Inventor); Hargrave, Brian (Inventor); Platt, Robert J., Jr. (Inventor)

2014-01-01

A robotic system includes a robotic mechanism responsive to velocity control signals, and a permissible workspace defined by a convex-polygon boundary. A host machine determines a position of a reference point on the mechanism with respect to the boundary, and includes an algorithm for enforcing the boundary by automatically shaping the velocity control signals as a function of the position, thereby providing smooth and unperturbed operation of the mechanism along the edges and corners of the boundary. The algorithm is suited for application with higher speeds and/or external forces. A host machine includes an algorithm for enforcing the boundary by shaping the velocity control signals as a function of the reference point position, and a hardware module for executing the algorithm. A method for enforcing the convex-polygon boundary is also provided that shapes a velocity control signal via a host machine as a function of the reference point position.

Calculation of three dimensional viscous flows in annular cascades using parabolized Navier-Stokes equations

NASA Astrophysics Data System (ADS)

Lawerenz, M.

Numerical algorithms for describing the endwall boundary layers and secondary flows in high turning turbine cascades are described. Partially-parabolic methods which cover three-dimensional viscous flow effects are outlined. Introduction of tip-clearance models and modifications of no-slip conditions without the use of wall functions expand the range of application and improve accuracy. Simultaneous computation of the profile boundary layers by refinement of the mesh size in the circumferential direction makes it possible to describe the boundary layer interaction in the corners formed by the bladings and the endwalls. The partially-parabolic method means that the streamwise elliptic coupling is well represented by the given pressure field and that separation does not occur, but it is not possible to describe the separation of the endwall boundary layer near the leading edge and the horse-shoe vortex there properly.

Accurate reconstruction in digital holographic microscopy using antialiasing shift-invariant contourlet transform

NASA Astrophysics Data System (ADS)

Zhang, Xiaolei; Zhang, Xiangchao; Xu, Min; Zhang, Hao; Jiang, Xiangqian

2018-03-01

The measurement of microstructured components is a challenging task in optical engineering. Digital holographic microscopy has attracted intensive attention due to its remarkable capability of measuring complex surfaces. However, speckles arise in the recorded interferometric holograms, and they will degrade the reconstructed wavefronts. Existing speckle removal methods suffer from the problems of frequency aliasing and phase distortions. A reconstruction method based on the antialiasing shift-invariant contourlet transform (ASCT) is developed. Salient edges and corners have sparse representations in the transform domain of ASCT, and speckles can be recognized and removed effectively. As subsampling in the scale and directional filtering schemes is avoided, the problems of frequency aliasing and phase distortions occurring in the conventional multiscale transforms can be effectively overcome, thereby improving the accuracy of wavefront reconstruction. As a result, the proposed method is promising for the digital holographic measurement of complex structures.

High Above Jupiter's Clouds

NASA Image and Video Library

2018-01-04

NASA's Juno spacecraft was a little more than one Earth diameter from Jupiter when it captured this mind-bending, color-enhanced view of the planet's tumultuous atmosphere. Jupiter completely fills the image, with only a hint of the terminator (where daylight fades to night) in the upper right corner, and no visible limb (the curved edge of the planet). Juno took this image of colorful, turbulent clouds in Jupiter's northern hemisphere on Dec. 16, 2017 at 9:43 a.m. PST (12:43 p.m. EST) from 8,292 miles (13,345 kilometers) above the tops of Jupiter's clouds, at a latitude of 48.9 degrees. The spatial scale in this image is 5.8 miles/pixel (9.3 kilometers/pixel).. Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21973

Anchored but not internalized: shape dependent endocytosis of nanodiamond

NASA Astrophysics Data System (ADS)

Zhang, Bokai; Feng, Xi; Yin, Hang; Ge, Zhenpeng; Wang, Yanhuan; Chu, Zhiqin; Raabova, Helena; Vavra, Jan; Cigler, Petr; Liu, Renbao; Wang, Yi; Li, Quan

2017-04-01

Nanoparticle-cell interactions begin with the cellular uptake of the nanoparticles, a process that eventually determines their cellular fate. In the present work, we show that the morphological features of nanodiamonds (NDs) affect both the anchoring and internalization stages of their endocytosis. While a prickly ND (with sharp edges/corners) has no trouble of anchoring onto the plasma membrane, it suffers from difficult internalization afterwards. In comparison, the internalization of a round ND (obtained by selective etching of the prickly ND) is not limited by its lower anchoring amount and presents a much higher endocytosis amount. Molecular dynamics simulation and continuum modelling results suggest that the observed difference in the anchoring of round and prickly NDs likely results from the reduced contact surface area with the cell membrane of the former, while the energy penalty associated with membrane curvature generation, which is lower for a round ND, may explain its higher probability of the subsequent internalization.

Role of thermal history in atomic dynamics of chalcogenide glass: A case study on Ge{sub 20}Te{sub 80} glass

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

Sharma, Yashika; Kalra, Geetanjali; Murugavel, Sevi, E-mail: murug@physics.du.ac.in

The non-existence of thermodynamic equilibrium in glasses, their thermal history plays a very crucial role in explaining the relaxation behavior in various time scales and its configurational states. More importantly, the associated relaxation behavior is related mainly to the structural phenomenon of the glasses. Here, we report the dependence of quenching rate on the variation of structural units. The local structures of these glasses are monitored by recording the Raman spectroscopy and related to the different configurational states. The observed variations in structural differences are reflected in the measured density of the corresponding glasses. The quenching rate dependent of themore » relative fractions of edge-shared and corner-shared GeTe{sub 4} tetrahedral units are shown to be consistent with the corresponding variations in the measured density values.« less

The effect of kerosene injection on ignition probability of local ignition in a scramjet combustor

NASA Astrophysics Data System (ADS)

Bao, Heng; Zhou, Jin; Pan, Yu

2017-03-01

The spark ignition of kerosene is investigated in a scramjet combustor with a flight condition of Ma 4, 17 km. Based plentiful of experimental data, the ignition probabilities of the local ignition have been acquired for different injection setups. The ignition probability distributions show that the injection pressure and injection location have a distinct effect on spark ignition. The injection pressure has both upper and lower limit for local ignition. Generally, the larger mass flow rate will reduce the ignition probability. The ignition position also affects the ignition near the lower pressure limit. The reason is supposed to be the cavity swallow effect on upstream jet spray near the leading edge, which will make the cavity fuel rich. The corner recirculation zone near the front wall of the cavity plays a significant role in the stabilization of local flame.

The crystal structure and crystal chemistry of fernandinite and corvusite

USGS Publications Warehouse

Evans, H.T.; Post, J.E.; Ross, D.R.; Nelen, J.A.

1994-01-01

Using type material of fernandinite from Minasragra, Peru, and corvusite from the Jack Claim, La Sal Mountains, Utah, the properties and crystal chemistry of these minerals have been determined by Rietveld analysis of the powder X-ray-diffraction patterns. The crystal structure of both species is isotypic with the V2O5 -type layer first found for ??-Ag0.68V2O5; it consists of chains of VO6 octahedra linked by opposite corners (parallel to b) condensed by edge-sharing to form the layer. The vanadium has average valence 4.8, and the resulting layer-charge is balanced by varying amounts of Ca, Na, and K in the interlayer region accompanied by labile water. This study has confirmed the validity of fernandinite as a unique mineral species. It is closely related to corvusite, from which it is distinguished on the basis of the dominant interlayer cation: Ca for fernandinite, Na for curvusite. -Authors

Redetermination of AgPO3

PubMed Central

Terebilenko, Katherina V.; Zatovsky, Igor V.; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.

2011-01-01

Single crystals of silver(I) polyphosphate(V), AgPO3, were prepared via a phospho­ric acid melt method using a solution of Ag3PO4 in H3PO4. In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779–784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO5] polyhedra, giving rise to multidirectional ribbons, and from two types of PO4 tetra­hedra linked into meandering chains (PO3)n spreading parallel to the b axis with a repeat unit of four tetra­hedra. The calculated bond-valence sum value of one of the two AgI ions indicates a significant strain of the structure. PMID:21522230

Optical proximity correction (OPC) in near-field lithography with pixel-based field sectioning time modulation

NASA Astrophysics Data System (ADS)

Oh, Seonghyeon; Han, Dandan; Shim, Hyeon Bo; Hahn, Jae W.

2018-01-01

Subwavelength features have been successfully demonstrated in near-field lithography. In this study, the point spread function (PSF) of a near-field beam spot from a plasmonic ridge nanoaperture is discussed with regard to the complex decaying characteristic of a non-propagating wave and the asymmetry of the field distribution for pattern design. We relaxed the shape complexity of the field distribution with pixel-based optical proximity correction (OPC) for simplifying the pattern image distortion. To enhance the pattern fidelity for a variety of arbitrary patterns, field-sectioning structures are formulated via convolutions with a time-modulation function and a transient PSF along the near-field dominant direction. The sharpness of corners and edges, and line shortening can be improved by modifying the original target pattern shape using the proposed approach by considering both the pattern geometry and directionality of the field decay for OPC in near-field lithography.

Optical proximity correction (OPC) in near-field lithography with pixel-based field sectioning time modulation.

PubMed

Oh, Seonghyeon; Han, Dandan; Shim, Hyeon Bo; Hahn, Jae W

2018-01-26

Subwavelength features have been successfully demonstrated in near-field lithography. In this study, the point spread function (PSF) of a near-field beam spot from a plasmonic ridge nanoaperture is discussed with regard to the complex decaying characteristic of a non-propagating wave and the asymmetry of the field distribution for pattern design. We relaxed the shape complexity of the field distribution with pixel-based optical proximity correction (OPC) for simplifying the pattern image distortion. To enhance the pattern fidelity for a variety of arbitrary patterns, field-sectioning structures are formulated via convolutions with a time-modulation function and a transient PSF along the near-field dominant direction. The sharpness of corners and edges, and line shortening can be improved by modifying the original target pattern shape using the proposed approach by considering both the pattern geometry and directionality of the field decay for OPC in near-field lithography.

Lake Powell, Colorado River, Utah and Grand Canyon, Arizona

NASA Image and Video Library

1973-06-22

SL2-04-018 (June 1973) --- A vertical view of the Arizona-Utah border area showing the Colorado River and Grand Canyon photographed from the Skylab 1/2 space station in Earth orbit. This picture was taken by one of the six lenses of the Itek-furnished S190-A Multispectral Photographic Facility Experiment in the Multiple Docking Adapter of the space station. Type S0-356 film was used. The row of white clouds extend north-south over the dark colored Kaibab Plateau. The junction of the Colorado and Little Colorado rivers is in the southwest corner of the picture. The body of water is Lake Powell on the Colorado River upstream from the Grand Canyon. The lone peak at the eastern edge of the photograph south of Colorado River is the 10,416-foot Navajo Mountain. The S190-A experiment is part of the Skylab Earth Resources Experiments Package(EREP). Photo credit: NASA

Galaxy Centaurus A

NASA Image and Video Library

2003-07-25

This image of the active galaxy Centaurus A was taken by NASA's Galaxy Evolution Explorer on June 7, 2003. The galaxy is located 30 million light-years from Earth and is seen edge on, with a prominent dust lane across the major axis. In this image the near ultraviolet emission is represented as green, and the far ultraviolet emission as blue. The galaxy exhibits jets of high energy particles, which were traced by the X-ray emission and measured by NASA's Chandra X-ray Observatory. These X-ray emissions are seen as red in the image. Several regions of ultraviolet emission can be seen where the jets of high energy particles intersect with hydrogen clouds in the upper left corner of the image. The emission shown may be the result of recent star formation triggered by the compression of gas by the jet. http://photojournal.jpl.nasa.gov/catalog/PIA04624

Fast and efficient indexing approach for object recognition

NASA Astrophysics Data System (ADS)

Hefnawy, Alaa; Mashali, Samia A.; Rashwan, Mohsen; Fikri, Magdi

1999-08-01

This paper introduces a fast and efficient indexing approach for both 2D and 3D model-based object recognition in the presence of rotation, translation, and scale variations of objects. The indexing entries are computed after preprocessing the data by Haar wavelet decomposition. The scheme is based on a unified image feature detection approach based on Zernike moments. A set of low level features, e.g. high precision edges, gray level corners, are estimated by a set of orthogonal Zernike moments, calculated locally around every image point. A high dimensional, highly descriptive indexing entries are then calculated based on the correlation of these local features and employed for fast access to the model database to generate hypotheses. A list of the most candidate models is then presented by evaluating the hypotheses. Experimental results are included to demonstrate the effectiveness of the proposed indexing approach.

Mojave Desert, California

NASA Image and Video Library

1973-06-22

SL2-03-126 (June 1973) --- A color infrared photograph of the Los Angeles County and Kern County area, taken from the Skylab space station in Earth orbit during its first manned Skylab mission. The Mojave Desert occupies the northeast one-fourth of the photograph. Lake Isabella in the Sierra Nevada Mountains is the v-shaped body of water. The San Gabriel Mountains extend across the southern part of the picture. At lower center is the intersection of the San Andreas and Garlock faults. The San Joaquin Valley is in the center at the left edge. (The picture should be held with the heavy cloud cover at lower right corner so that north will be at top.) This picture was exposed by one of the six lenses of the Itek-furnished S190-A Multispectral Photographic Facility experiment in the Multiple Docking Adapter of the Skylab space station. Type 2443 film was used. Photo credit: NASA

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.

Damage-induced reactive oxygen species regulate vimentin and dynamic collagen-based projections to mediate wound repair

PubMed Central

Freisinger, Chrissy; Rindy, Julie; Golenberg, Netta; Frecentese, Grace; Gibson, Angela; Eliceiri, Kevin W

2018-01-01

Tissue injury leads to early wound-associated reactive oxygen species (ROS) production that mediate tissue regeneration. To identify mechanisms that function downstream of redox signals that modulate regeneration, a vimentin reporter of mesenchymal cells was generated by driving GFP from the vimentin promoter in zebrafish. Early redox signaling mediated vimentin reporter activity at the wound margin. Moreover, both ROS and vimentin were necessary for collagen production and reorganization into projections at the leading edge of the wound. Second harmonic generation time-lapse imaging revealed that the collagen projections were associated with dynamic epithelial extensions at the wound edge during wound repair. Perturbing collagen organization by burn wound disrupted epithelial projections and subsequent wound healing. Taken together our findings suggest that ROS and vimentin integrate early wound signals to orchestrate the formation of collagen-based projections that guide regenerative growth during efficient wound repair. PMID:29336778

46 CFR 163.002-13 - Construction.

Code of Federal Regulations, 2013 CFR

2013-10-01

... sharp edges and projections of excessive length. A pilot hoist must not have nonfunctional sharp edges... vessel's side rails for support; and (3) Unobstructed passage between the ladder or lift platform of the... between the vessel's compressed air source and the pneumatic motor. (l) Hoist control lever. Each pilot...

46 CFR 163.002-13 - Construction.

Code of Federal Regulations, 2014 CFR

2014-10-01

... sharp edges and projections of excessive length. A pilot hoist must not have nonfunctional sharp edges... vessel's side rails for support; and (3) Unobstructed passage between the ladder or lift platform of the... between the vessel's compressed air source and the pneumatic motor. (l) Hoist control lever. Each pilot...

46 CFR 163.002-13 - Construction.

Code of Federal Regulations, 2012 CFR

2012-10-01

... sharp edges and projections of excessive length. A pilot hoist must not have nonfunctional sharp edges... vessel's side rails for support; and (3) Unobstructed passage between the ladder or lift platform of the... between the vessel's compressed air source and the pneumatic motor. (l) Hoist control lever. Each pilot...