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1

Apparatus and methods for installing, removing and adjusting an inner turbine shell section relative to an outer turbine shell section  

DOEpatents

A turbine includes upper and lower inner shell sections mounting the nozzles and shrouds and which inner shell is supported by pins secured to a surrounding outer shell. To disassemble the turbine for access to the inner shell sections and rotor, an alignment fixture is secured to the lower outer shell section and has pins engaging the inner shell section. To disassemble the turbine, the inner shell weight is transferred to the lower outer shell section via the alignment fixture and cradle pins. Roller assemblies are inserted through access openings vacated by support pins to permit rotation of the lower inner shell section out of and into the lower outer shell section during disassembly and assembly. The alignment fixture includes adjusting rods for adjusting the inner shell axially, vertically, laterally and about a lateral axis. A roller over-cage is provided to rotate the inner shell and a dummy shell to facilitate assembly and disassembly in the field.

Leach, David (Niskayuna, NY); Bergendahl, Peter Allen (Scotia, NY); Waldo, Stuart Forrest (Salem, NC); Smith, Robert Leroy (Milford, OH); Phelps, Robert Kim (Milford, OH)

2001-01-01

2

Resource partitioning and competition for shells between intertidal hermit crabs on the outer coast of Washington  

Microsoft Academic Search

Resource partitioning was quantified for 6 species of intertidal hermit crabs in the genus Pagurus, that occur on the outer coast of Washington. This, together with field evidence of shell shortage and with laboratory experiments to quantify the mechanism of interactions for shells, allowed estimation of the relative intensities of inter-and intraspecific competition between these species. The findings were that:

P. A. Abrams

1987-01-01

3

Comparative study of the shell development of hard- and soft-shelled turtles.  

PubMed

The turtle shell provides a fascinating model for the investigation of the evolutionary modifications of developmental mechanisms. Different conclusions have been put forth for its development, and it is suggested that one of the causes of the disagreement could be the differences in the species of the turtles used - the differences between hard-shelled turtles and soft-shelled turtles. To elucidate the cause of the difference, we compared the turtle shell development in the two groups of turtle. In the dorsal shell development, these two turtle groups shared the gene expression profile that is required for formation, and shared similar spatial organization of the anatomical elements during development. Thus, both turtles formed the dorsal shell through a folding of the lateral body wall, and the Wnt signaling pathway appears to have been involved in the development. The ventral portion of the shell, on the other hand, contains massive dermal bones. Although expression of HNK-1 epitope has suggested that the trunk neural crest contributed to the dermal bones in the hard-shelled turtles, it was not expressed in the initial anlage of the skeletons in either of the types of turtle. Hence, no evidence was found that would support a neural crest origin. PMID:24754673

Nagashima, Hiroshi; Shibata, Masahiro; Taniguchi, Mari; Ueno, Shintaro; Kamezaki, Naoki; Sato, Noboru

2014-07-01

4

Search for the Outer Shell of the Crab Nebula  

Microsoft Academic Search

The Crab Nebula is unique among supernova remnants in that there is no evidence for rapidly moving debris from the explosion. We propose to search for an outer shock with sensitivity 10-100 times that of previous X-ray observations. If found, the properties of the shock will determine properties of the progenitor star. Chandra is very well suited for this observation.

Frederick Seward

2001-01-01

5

Evolution of Titan's outer icy shell: Role of ocean crystallization and surface weathering  

NASA Astrophysics Data System (ADS)

The Cassini-Huygens mission has brought evidences for an internal ocean lying under an outer ice shell. The structure and evolution of the outer ice shell and of the internal ocean are essential to understand Titan's surface morphology as well as its atmosphere evolution. The observed shape and the gravity field of Titan provide information on the present-day structure of the H2O mantle, in terms of ocean/ice interface depth and crustal density. By modeling consistently topography and gravity data, we have quantified the amplitudes of ice shell thickness and/or crustal density variations. Moreover, we have constrained the possible viscosity structure of the outer shell and thermal gradients by modeling the topography relaxation rate. Lateral variations in the thickness of the outer ice shell may be explained by heterogeneous ocean crystallization, while surface weathering by liquid hydrocarbons may generate surface erosion and crustal alteration. To determine how these processes affect Titan's dynamics, we model heat and mass transfers between the internal ocean, the ice shell and the atmosphere and we determine the time evolution of long-wavelength topography and surface stress patterns for different evolutionary scenarios. Finally, we compare our predicted maps of surface stress and heat flux anomalies with the global repartition of the morphological features observed by VIMS and Radar.

Lefevre, A.; Tobie, G.; Amit, H.; Cadek, O.; Choblet, G.; Le Mouelic, S.; Mitri, G.; Sotin, C.

2013-12-01

6

DETECTING THE RAPIDLY EXPANDING OUTER SHELL OF THE CRAB NEBULA: WHERE TO LOOK  

SciTech Connect

We present a range of steady-state photoionization simulations, corresponding to different assumed shell geometries and compositions, of the unseen postulated rapidly expanding outer shell to the Crab Nebula. The properties of the shell are constrained by the mass that must lie within it, and by limits to the intensities of hydrogen recombination lines. In all cases the photoionization models predict very strong emissions from high ionization lines that will not be emitted by the Crab's filaments, alleviating problems with detecting these lines in the presence of light scattered from brighter parts of the Crab. The near-NIR [Ne VI] {lambda}7.652 {mu}m line is a particularly good case; it should be dramatically brighter than the optical lines commonly used in searches. The C IV {lambda}1549 doublet is predicted to be the strongest absorption line from the shell, which is in agreement with Hubble Space Telescope observations. We show that the cooling timescale for the outer shell is much longer than the age of the Crab, due to the low density. This means that the temperature of the shell will actually ''remember'' its initial conditions. However, the recombination time is much shorter than the age of the Crab, so the predicted level of ionization should approximate the real ionization. In any case, it is clear that IR observations present the best opportunity to detect the outer shell and so guide future models that will constrain early events in the original explosion.

Wang Xiang; Ferland, G. J. [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Baldwin, J. A.; Loh, E. D.; Richardson, C. T., E-mail: xiang.wang@uky.edu [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824-2320 (United States)

2013-09-10

7

Matrix Proteins in the Outer Shells of Molluscs  

Microsoft Academic Search

The shells of molluscs are composed mainly of calcium carbonate crystals, with small amounts of matrix proteins. For more\\u000a than 50 years, they have attracted attention for their unique mechanical and biological properties. Only recently, however,\\u000a have researchers begun to realize that it is the matrix proteins that control the formation of calcium carbonate crystals\\u000a and play key roles in

Cen Zhang; Rongqing Zhang

2006-01-01

8

Search for the Outer Shell of the Crab Nebula  

NASA Astrophysics Data System (ADS)

The Crab Nebula is unique among supernova remnants in that there is no evidence for rapidly moving debris from the explosion. We propose to search for an outer shock with sensitivity 10-100 times that of previous X-ray observations. If found, the properties of the shock will determine properties of the progenitor star. Chandra is very well suited for this observation. We will also obtain an excellent image of the dust halo. Properties of the interstellar grains and their distribution can be derived.

Seward, Frederick

2001-09-01

9

Ultrastructural characteristics of ostrich eggshell: outer shell membrane and the calcified layers.  

PubMed

The ultrastructure of the eggshell of the domestic hen has been well researched and structural studies of other avian species, such as the ostrich, often base their interpretation of egg shell structure on that of the chicken. In the ostrich, lowered hatchability and hatching trauma may be due to shell ultrastructural abnormalities. In the present study the ultrastructure of the calcified portion, and the outer shell membrane (OSM), of domesticated ostrich eggshells was investigated using standard electron microscopic techniques. Transmission and scanning electron microscopy studies demonstrated intimate contact between cup-shaped structures present on the OSM and the mammillary layer of the calcified portion of the shell. The initial calcium carbonate growth of the calcified shell was of a dendritic nature with nucleation sites on the surface of the cup's contents. The dendritic growth gave way to a more randomly-orientated, smaller crystallite growth structure, which changed in form as it neared the vertical crystal layer (VCL). The VCL is described as being both amorphous and 'crumbly' depending on the plane of fracture. These observations suggest that firstly, initial calcification is contained within the cups and is then directed outwards to form the shell and that secondly, the VCL may contain an evolutionary, calcified cuticular layer. These observations serve as a baseline for studies investigating the effect of shell structure and strength on hatchling trauma and the influence of maternal diet. PMID:11030359

Richards, P D; Richards, P A; Lee, M E

2000-06-01

10

Surface response of spherical core-shell structured nanoparticle by optically induced elastic oscillations of soft shell against hard core  

E-print Network

The optically induced oscillatory response of a spherical two-component, shell-core structured, nanoparticle by nodeless elastic vibrations of soft peripheral shell against hard and dynamically immobile inner core is considered. The eigenfrequencies of the even-parity, spheroidal and odd-parity torsional vibrational modes trapped in the finite-depth shell are obtained which are of practical interest for modal specification of individual resonances in spectra of resonant scattering of long wavelength electromagnetic waves by ultrafine particles.

S. I. Bastrukov; P. -Y. Lai; I. V. Molodtsova; H. -K. Chang; D. V. Podgainy

2009-03-13

11

HOW SOME POLLUTANTS AFFECT EMBRYOS & LARVAE OF AMERICAN OYSTER & HARD-SHELL CLAM  

E-print Network

T his article reports the effects of detergents, pH, and pe s ticide s on development of embryos and survival and growth of larvae of the American oy ster and hard -shell clam. Although LAS detergents , Crassostrea vir- ginica, and the hard -she ll cla m, Mercenaria mercenaria. The effects of detergents, p

12

Scattering functions of core-shell-structured hard spheres with Schulz-distributed radii.  

PubMed

The scattering intensity of polydisperse systems of core-shell and layered hard spheres is considered. The Percus-Yevick solution for the partial structure factors is cast in a form suitable for numerical and analytical treatment. Closed-form, analytical expressions are given for an effective hard-sphere model of the scattering intensity of particles with an internal layered structure and a size polydispersity governed by a Schulz distribution. A similar model for polydisperse hard spheres of core-shell structure but with a monodisperse shell thickness is also presented. The models are tested against small-angle X-ray scattering experiments on a hard-sphere-like microemulsion system. PMID:19462945

Nayeri, M; Zackrisson, M; Bergenholtz, J

2009-06-18

13

Quantifying Shell Hardness in the Southern Rock Lobster (Jasus edwardsii)  

Microsoft Academic Search

Southern rock lobsters Jasus edwardsii that are about to moult or have recently moulted have reduced market value due to higher mortality in live transport, higher cannibalism and lower meat recovery. Limiting the landing of softer shelled lobsters is desirable to maintain product quality; however, attempts to set closed seasons or to introduce industry self-regulation have been hampered by subjectivity

Caleb Gardnerm; Richard Musgrove

2006-01-01

14

The original kinematic plate tectonic model proposed that the outer shell (lithosphere) of the Earth is divided into a small  

E-print Network

The original kinematic plate tectonic model proposed that the outer shell (lithosphere driver of plate tectonics and mantle convection, but much of the energy dissipation may be in this part rele- vant to plate tectonics. Here we have compiled a series of global maps that help to confirm

Sandwell, David T.

15

The pollen tube: a soft shell with a hard core Hannes Vogler1  

E-print Network

The pollen tube: a soft shell with a hard core Hannes Vogler1 , Christian Draeger1 , Alain Weber2 in-depth knowl- edge of cell wall mechanics. Pollen tubes are tip-growing cells that provide an ideal it was not easy to measure important mechanical parameters of pollen tubes, such as the elasticity of the cell

Kuhlemeier, Cris

16

Triple assembly of ZnO, large-scale hollow spherical shells with flower-like species consisting of rods grown on the outer surfaces of shells  

SciTech Connect

Novel large-scale hollow ZnO spherical shells were synthesized by ionic liquids assisted hydrothermal oxidization of pure zinc powder without any catalyst at a relatively low temperature of 160 deg. C. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) patterns show that the shells are composed of ZnO and the structure of the shells is very unique. Textured flower-like ZnO consisting of ZnO rods is grown on the outer surfaces of shells forming a triple assembly. Room-temperature photoluminescence spectra of the oxidized material show a sharp peak at 379 nm and a wider broad peak centered at 498 nm. The possible growth mechanism of the triple assembly of ZnO is discussed in detail. - Graphical abstract: A proposed growth mechanism of large scale hollow ZnO. Bubbles provide the aggregation center for ionic liquids that leads to the formation of hollow Zn particle-dotted shells, buoyancy promotes shells to go upward, the breach occurs when shells are subjected to overpressure.

Shang Yazhuo; Hu Jun [Key Laboratory for Advanced Materials, East China University of Science and Technology, Shanghai, 200237 (China); Liu Honglai, E-mail: yazhuoshang@ecust.edu.c [Key Laboratory for Advanced Materials, East China University of Science and Technology, Shanghai, 200237 (China); Hu Ying [Key Laboratory for Advanced Materials, East China University of Science and Technology, Shanghai, 200237 (China)

2010-03-15

17

Building nanocomposite magnets by coating a hard magnetic core with a soft magnetic shell.  

PubMed

Controlling exchange coupling between hard magnetic and soft magnetic phases is the key to the fabrication of advanced magnets with tunable magnetism and high energy density. Using FePt as an example, control over the magnetism in exchange-coupled nanocomposites of hard magnetic face-centered tetragonal (fct) FePt and soft magnetic Co (or Ni, Fe2C) is shown. The dispersible hard magnetic fct-FePt nanoparticles are first prepared with their coercivity (Hc) reaching 33?kOe. Then core/shell fct-FePt/Co (or Ni, Fe2C) nanoparticles are synthesized by reductive thermal decomposition of the proper metal precursors in the presence of fct-FePt nanoparticles. These core/shell nanoparticles are strongly coupled by exchange interactions and their magnetic properties can be rationally tuned by the shell thickness of the soft phase. This work provides an ideal model system for the study of exchange coupling at the nanoscale, which will be essential for building superstrong magnets for various permanent magnet applications in the future. PMID:24453167

Liu, Fei; Zhu, Jinghan; Yang, Wenlong; Dong, Yunhe; Hou, Yanglong; Zhang, Chenzhen; Yin, Han; Sun, Shouheng

2014-02-17

18

Multiple outer-shell ionization effect in inner-shell x-ray production by light ions  

SciTech Connect

L-shell x-ray production cross sections by 0.25--2.5-MeV /sub 2//sup 4/He/sup +/ ions in /sub 28/Ni, /sub 29/Cu, /sub 32/Ge, /sub 33/As, /sub 37/Rb, /sub 38/Sr, /sub 39/Y, /sub 40/Zr, and /sub 46/Pd are reported. The data are compared to the first Born approximation and the ECPSSR theory that accounts for the projectile energy loss (E) and Coulomb deflection (C) as well as the perturbed-stationary-state (PSS) and relativistic (R) effects in the treatment of the target L-shell electron. Surprisingly, the first Born approximation appears to converge to the data while the ECPSSR predictions underestimate them in the low-velocity limit. This is explained as the result of improper use of single-hole fluorescence yields. A heuristic formula is proposed to account for multiple ionizations in terms of a classical probability for these phenomena and, after it is applied, the ECPSSR theory of L-shell ionization is found to be in good agreement with the data.

Lapicki, G.; Mehta, R.; Duggan, J.L.; Kocur, P.M.; Price, J.L.; McDaniel, F.D.

1986-11-01

19

Two Large H I Shells in the Outer Galaxy near L=279°  

NASA Astrophysics Data System (ADS)

As part of a survey of H I ?21 cm emission in the southern Milky Way, we have detected two large shells in the interstellar neutral hydrogen near l=279°. The center velocities are +36 and +59 km s-1, which puts the shells at kinematic distances of 7 and 10 kpc. The larger shell is about 610 pc in diameter and very empty, with density contrast of at least 15 between the middle and the shell walls. It has expansion velocity of about 20 km s-1 and swept-up mass of several million solar masses. The energy indicated by the expansion may be as high as 2.4×1053 ergs. We estimate its age to be 15 to 20 million years. The smaller shell has diameter of about 400 pc, expansion velocity about 10 km s-1, and swept-up mass of about 106 Msolar. Morphologically both regions appear to be shells, with high-density regions mostly surrounding the voids, although the first appears to have channels of low density that connect with the halo above and below the H I layer. They lie on the edge of the Carina arm, which suggests that they may be expanding horizontally into the interarm region, as well as vertically out of the disk. If this interpretation is correct, this is the first detection of an H I chimney which has blown out of both sides of the disk.

McClure-Griffiths, N. M.; Dickey, John M.; Gaensler, B. M.; Green, A. J.; Haynes, R. F.; Wieringa, M. H.

2000-06-01

20

Two Large HI Shells in the Outer Galaxy near l=279 degrees  

E-print Network

As part of a survey of HI 21-cm emission in the Southern Milky Way, we have detected two large shells in the interstellar neutral hydrogen near l=279 deg. The center velocities are +36 and +59 km/s, which puts the shells at kinematic distances of 7 and 10 kpc. The larger shell is about 610 pc in diameter and very empty, with density contrast of at least 15 between the middle and the shell walls. It has expansion velocity of about 20 km/s and swept up mass of several million solar masses. The energy indicated by the expansion may be as high as 2.4 X 10^53 ergs. We estimate its age to be 15 to 20 million years. The smaller shell has diameter of about 400 pc, expansion velocity about 10 km/s and swept up mass of about 10^6 solar masses. Morphologically both regions appear to be shells, with high density regions mostly surrounding the voids, although the first appears to have channels of low density which connect with the halo above and below the HI layer. They lie on the edge of the Carina arm, which suggests that they may be expanding horizontally into the interarm region as well as vertically out of the disk. If this interpretation is correct, this is the first detection of an HI chimney which has blown out of both sides of the disk.

N. M. McClure-Griffiths; John M. Dickey; B. M. Gaensler; A. J. Green; R. F. Haynes; M. H. Wieringa

2000-03-11

21

Multiple outer-shell ionization effect in inner-shell x-ray production by light ions  

Microsoft Academic Search

L-shell x-ray production cross sections by 0.25--2.5-MeV â⁴He\\/sup +\\/ ions in ââNi, ââCu, ââGe, ââAs, ââRb, ââSr, ââY, ââZr, and ââPd are reported. The data are compared to the first Born approximation and the ECPSSR theory that accounts for the projectile energy loss (E) and Coulomb deflection (C) as well as the perturbed-stationary-state (PSS) and relativistic (R) effects in the

G. Lapicki; R. Mehta; J. L. Duggan; P. M. Kocur; J. L. Price; F. D. McDaniel

1986-01-01

22

Multiple outer-shell ionization effect in inner-shell x-ray production by light ions  

Microsoft Academic Search

L-shell x-ray production cross sections by 0.25-2.5-MeV 42He+ ions in 28Ni, 29Cu, 32Ge, 33As, 37Rb, 38Sr, 39Y, 40Zr, and 46Pd are reported. The data are compared to the first Born approximation and the ECPSSR theory that accounts for the projectile energy loss (E) and Coulomb deflection (C) as well as the perturbed-stationary-state (PSS) and relativistic (R) effects in the treatment

G. Lapicki; R. Mehta; J. L. Duggan; P. M. Kocur; J. L. Price; F. D. McDaniel

1986-01-01

23

VideoLab: Holding on by a (Hard-Shell) Thread  

NSDL National Science Digital Library

Similar in concept to spider silk, mussels use a thread-like, acellular tissue called the byssus (or â??beardâ?) to anchor themselves in turbulent aqueous environments. The movie shows the musselâ??s foot attaching to and detaching from a surface, leaving behind an adhesive pad and rope-like byssal thread that keeps the mussel affixed to the surface. A Perspective by P.B. Messersmith reports on recent study of the chemistry of byssal thread cuticles. It highlights the importance of the catecholic amino acid dopa, which coordinates with iron to fabricate the byssus' hard-shelled cuticles.

Phillip B. Messersmith (Northwestern University; Departments of Biomedical Engineering, Materials Science and Engineering, Chemical and Biological Engineering, Chemistry of Life Processes Institute, and Institute for Bionanotechnology in Medicine)

2010-04-09

24

Collision safety of a hard-shell low-mass vehicle  

SciTech Connect

Low-mass vehicles and in particular low-mass electric vehicles as produced today in very small quantities are in general not designed for crashworthiness in collisions. Particular problems of compact low-mass cars are: reduced length of the car front, low mass compared to other vehicles, and heavy batteries in the case of an electric car. With the intention of studying design improvements, three frontal crash tests were run last year: the first one with a commercial, lightweight electric car; the second with a reinforced version of the same car; and the last one with a car based on a different structural design with a `hard-shell` car body. Crash tests showed that the latter solution made better use of the small zone available for continuous energy absorption. The paper discusses further the problem of frontal collisions between vehicles of different weight and, in particular, the side collision. A side-collision test was run with the hard-shell vehicle following the ECE lateral-impact test procedure at 50 km/h and led to results for the EuroSIDI-dummy well below current injury tolerance criteria.

Kaeser, R.; Walz, F.H.; Brunner, A.

1994-06-01

25

The performance and radiation hardness of the Outer Tracker detector for LHCb  

NASA Astrophysics Data System (ADS)

The LHCb experiment is designed to study B and D-meson decays at the LHC, in the forward region. It is crucial to accurately and efficiently detect the charged decay particles in the high-density particle environment of the LHC. For this, the Outer Tracker (OT) has been constructed. The detector has operated reliably under the challenging LHC conditions in 2011 and 2012. The performance of the detector is discussed in terms of high voltage stability, noise rate and single hit efficiency. New results on the hit resolution are presented. Finally, latest results on the radiation tolerance of this sensitive gas detector are discussed, after having received a total dose corresponding to about 100 mC/cm in the hottest region, and having operated with proton-ion collisions in 2013.

Gersabeck, E.

2014-06-01

26

Some Investigations on Hardness of Investment Casting Process After Advancements in Shell Moulding for Reduction in Cycle Time  

NASA Astrophysics Data System (ADS)

In the present work surface hardness investigations have been made on acrylonitrile butadiene styrene (ABS) pattern based investment castings after advancements in shell moulding for replication of biomedical implants. For the present study, a hip joint, made of ABS material, was fabricated as a master pattern by fused deposition modelling (FDM). After preparation of master pattern, mold was prepared by deposition of primary (1°), secondary (2°) and tertiary (3°) coatings with the addition of nylon fibre (1-2 cm in length of 1.5D). This study outlines the surface hardness mechanism for cast component prepared from ABS master pattern after advancement in shell moulding. The results of study highlight that during shell production, fibre modified shells have a much reduced drain time. Further the results are supported by cooling rate and micro structure analysis of casting.

Singh, R.; Mahajan, V.

2014-07-01

27

Flexural models of trench/outer rise topography of coronae on Venus with axisymmetric spherical shell elastic plates  

NASA Technical Reports Server (NTRS)

Magellan altimetry has revealed that many coronae on Venus have trenches or moats around their peripheries and rises outboard of the trenches. This trench/outer rise topographic signature is generally associated with the tectonic annulus of the corona. Sandwell and Schubert have interpreted the trench/outer rise topography and the associated tectonic annulus around coronae to be the result of elastic bending of the Venus lithosphere (though the tectonic structures are consequences of inelastic deformation of the lithosphere). They used two-dimensional elastic plate flexure theory to fit topographic profiles across a number of large coronae and inferred elastic lithosphere thicknesses between about 15 and 40 km, similar to inferred values of elastic thickness for the Earth's lithosphere at subduction zones around the Pacific Ocean. Here, we report the results of using axisymmetric elastic flexure theory for the deformation of thin spherical shell plates to interpret the trench/outer rise topography of the large coronae modeled by Sandwell and Schubert and of coronae as small as 250 km in diameter. In the case of a corona only a few hundred kilometers in diameter, the model accounts for the small planform radius of the moat and the nonradial orientation of altimetric traces across the corona. By fitting the flexural topography of coronae we determine the elastic thickness and loading necessary to account for the observed flexure. We calculate the associated bending moment and determine whether the corona interior topographic load can provide the required moment. We also calculate surface stresses and compare the stress distribution with the location of annular tectonic features.

Moore, W.; Schubert, Gerald; Sandwell, David T.

1992-01-01

28

Evidence for a Highly Elastic Shell-Core Organization of Cochlear Outer Hair Cells by Local Membrane Indentation  

PubMed Central

Cochlear outer hair cells (OHCs) are thought to play an essential role in the high sensitivity and sharp frequency selectivity of the hearing organ by generating forces that amplify the vibrations of this organ at frequencies up to several tens of kHz. This tuning process depends on the mechanical properties of the cochlear partition, which OHC activity has been proposed to modulate on a cycle-by-cycle basis. OHCs have a specialized shell-core ultrastructure believed to be important for the mechanics of these cells and for their unique electromotility properties. Here we use atomic force microscopy to investigate the mechanical properties of isolated living OHCs and to show that indentation mechanics of their membrane is consistent with a shell-core organization. Indentations of OHCs are also found to be highly nonhysteretic at deformation rates of more than 40 ?m/s, which suggests the OHC lateral wall is a highly elastic structure, with little viscous dissipation, as would appear to be required in view of the very rapid changes in shape and mechanics OHCs are believed to undergo in vivo. PMID:15653728

Zelenskaya, Alexandra; Boutet de Monvel, Jacques; Pesen, Devrim; Radmacher, Manfred; Hoh, Jan H.; Ulfendahl, Mats

2005-01-01

29

A Detailed Kinematic Map of Cassiopeia A's Optical Main Shell and Outer High-velocity Ejecta  

NASA Astrophysics Data System (ADS)

We present three-dimensional (3D) kinematic reconstructions of optically emitting material in the young Galactic supernova remnant Cassiopeia A (Cas A). These Doppler maps have the highest spectral and spatial resolutions of any previous survey of Cas A and represent the most complete catalog of its optically emitting material to date. We confirm that the bulk of Cas A's optically bright ejecta populate a torus-like geometry tilted approximately 30° with respect to the plane of the sky with a -4000 to +6000 km s-1 radial velocity asymmetry. Near-tangent viewing angle effects and an inhomogeneous surrounding circumstellar material/interstellar medium environment suggest that this geometry and velocity asymmetry may not be faithfully representative of the remnant's true 3D structure or the kinematic properties of the original explosion. The majority of the optical ejecta are arranged in several well-defined and nearly circular ring-like structures with diameters between approximately 30'' (0.5 pc) and 2' (2 pc). These ejecta rings appear to be a common phenomenon of young core-collapse remnants and may be associated with post-explosion input of energy from plumes of radioactive 56Ni-rich ejecta that rise, expand, and compress non-radioactive material. Our optical survey encompasses Cas A's faint outlying ejecta knots and exceptionally high-velocity NE and SW streams of S-rich debris often referred to as "jets." These outer knots, which exhibit a chemical make-up suggestive of an origin deep within the progenitor star, appear to be arranged in opposing and wide-angle outflows with opening half-angles of ?40°.

Milisavljevic, Dan; Fesen, Robert A.

2013-08-01

30

A DETAILED KINEMATIC MAP OF CASSIOPEIA A'S OPTICAL MAIN SHELL AND OUTER HIGH-VELOCITY EJECTA  

SciTech Connect

We present three-dimensional (3D) kinematic reconstructions of optically emitting material in the young Galactic supernova remnant Cassiopeia A (Cas A). These Doppler maps have the highest spectral and spatial resolutions of any previous survey of Cas A and represent the most complete catalog of its optically emitting material to date. We confirm that the bulk of Cas A's optically bright ejecta populate a torus-like geometry tilted approximately 30 Degree-Sign with respect to the plane of the sky with a -4000 to +6000 km s{sup -1} radial velocity asymmetry. Near-tangent viewing angle effects and an inhomogeneous surrounding circumstellar material/interstellar medium environment suggest that this geometry and velocity asymmetry may not be faithfully representative of the remnant's true 3D structure or the kinematic properties of the original explosion. The majority of the optical ejecta are arranged in several well-defined and nearly circular ring-like structures with diameters between approximately 30'' (0.5 pc) and 2' (2 pc). These ejecta rings appear to be a common phenomenon of young core-collapse remnants and may be associated with post-explosion input of energy from plumes of radioactive {sup 56}Ni-rich ejecta that rise, expand, and compress non-radioactive material. Our optical survey encompasses Cas A's faint outlying ejecta knots and exceptionally high-velocity NE and SW streams of S-rich debris often referred to as ''jets''. These outer knots, which exhibit a chemical make-up suggestive of an origin deep within the progenitor star, appear to be arranged in opposing and wide-angle outflows with opening half-angles of Almost-Equal-To 40 Degree-Sign.

Milisavljevic, Dan [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA, 02138 (United States); Fesen, Robert A., E-mail: dmilisav@cfa.harvard.edu [6127 Wilder Lab, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

2013-08-01

31

Oxygen and Carbon Stable Isotope and Sr:Ca Records in Outer and Middle Microstructural Layers of Bivalve Shells (Mercenaria campechiensis)  

NASA Astrophysics Data System (ADS)

? 18O, ? 13C, and Sr:Ca records contained in the aragonitic shells of the northern and southern quahogs (Mercenaria mercenaria and M. campechiensis, respectively) have been used in paleoclimate and paleoecological studies, although these environmental proxies have not yet been calibrated. Early geochemical studies of quahog shells focused on the outer prismatic layer. Because of innovations in microsampling techniques, recent studies focus on the middle cross-lamellar layer, providing high temporal resolution. Do both microstructural layers record similar profiles of ? 18O, ? 13C, and Sr:Ca? If not, which layer more faithfully records ambient conditions? Here, we provide a preliminary calibration of ? 18O and ? 13C using shells of M. campechiensis and test the hypothesis that both microstructural layers record similar geochemical information. Quahogs were collected alive near Bokeelia, SW Florida. The USGS maintained fortnightly to monthly temperature and salinity records at this site. These data, together with mixing equations of ? 18OWATER- and ? 13CDIC-salinity, were used to construct predictive model shells. The last 2 years of shell growth were sampled at 0.1-0.5 mm intervals yielding ˜100 ? g of material that was split for isotopic and elemental analyses. Comparison of model and observed shells reveals a predictable offset in ? 18O, where the model is offset by +1.3‰ relative to the observed shell. When corrected for the offset, ? 18O shell closely matches the model. Values range from -2.5 to +2‰ . Profiles of ? 18O from outer and middle layers are nearly identical. ? 13C of the middle layer is more variable and can be as much as 2.4‰ more positive than the outer layer. Observed ? 13C in the middle layer follows the general trend of the model, but winter-spring shell growth is offset by -1.7‰ relative to the model. Sr:Ca ratios from the middle layer can be as much as 0.4 mmol/mol higher than the outer layer. We conclude that either microstructural layer can be used to study variation in ? 18O because both layers preserve nearly identical profiles. Observed offsets in ? 13C and Sr:Ca ratios between microstructural layers can potentially complicate calibration and environmental/ climate reconstructions. The next phase of our research is to understand the mechanisms that control these offsets and determine which microstructural layer is better suited for geochemical study.

Surge, D.; Owens, S.

2003-12-01

32

Imprinting on empty hard gelatin capsule shells containing titanium dioxide by application of the UV laser printing technique.  

PubMed

The purpose of this study was to examine the application of ultraviolet (UV) laser irradiation to printing hard gelatin capsule shells containing titanium dioxide (TiO2) and to clarify how the color strength of the printing by the laser could be controlled by the power of the irradiated laser. Hard gelatin capsule shells containing 3.5% TiO2 were used in this study. The capsules were irradiated with pulsed UV laser at a wavelength of 355 nm. The color strength of the printed capsule was determined by a spectrophotometer as total color difference (dE). The capsules could be printed gray by the UV laser. The formation of many black particles which were agglomerates of oxygen-defected TiO2 was associated with the printing. In the relationship between laser peak power of a pulse and dE, there were two inflection points. The lower point was the minimal laser peak power to form the black particles and was constant regardless of the dosage forms, for example film-coated tablets, soft gelatin capsules and hard gelatin capsules. The upper point was the minimal laser peak power to form micro-bubbles in the shells and was variable with the formulation. From the lower point to the upper point, the capsules were printed gray and the dE of the printing increased linearly with the laser peak power. Hard gelatin capsule shells containing TiO2 could be printed gray using the UV laser printing technique. The color strength of the printing could be controlled by regulating the laser energy between the two inflection points. PMID:23786207

Hosokawa, Akihiro; Kato, Yoshiteru; Terada, Katsuhide

2014-08-01

33

Migration of Salmonella Enteritidis PT 30 through almond hulls and shells  

Technology Transfer Automated Retrieval System (TEKTRAN)

The ability of Salmonella to migrate from an external aqueous environment through the almond hull and shell, and to colonize the kernel, was evaluated in two ways. First, the outer surface of shell halves from five varieties of almonds that differed in shell hardness were placed in contact with a s...

34

Uptake and adherence with soft- and hard-shelled hip protectors in Norwegian nursing homes: a cluster randomised trial  

Microsoft Academic Search

Summary  A comparison between soft- and hard-shelled hip protectors in nursing homes shows no clinical relevant difference in acceptance\\u000a and probability of continued use. However, significantly more users of the soft hip protector used the protector 24 hours\\u000a a day.\\u000a \\u000a \\u000a \\u000a Introduction and hypothesis  Uptake and adherence with the use of hip protectors are poor due to discomfort and impracticality. The aim of

H. Bentzen; L. Forsén; C. Becker; A. Bergland

2008-01-01

35

7 CFR 51.2289 - Shell.  

Code of Federal Regulations, 2013 CFR

...FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2289 Shell. Shell means the outer shell and/or the woody...

2013-01-01

36

7 CFR 51.2289 - Shell.  

Code of Federal Regulations, 2012 CFR

...FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2289 Shell. Shell means the outer shell and/or the woody...

2012-01-01

37

7 CFR 51.2289 - Shell.  

Code of Federal Regulations, 2011 CFR

...FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2289 Shell. Shell means the outer shell and/or the woody...

2011-01-01

38

7 CFR 51.2289 - Shell.  

Code of Federal Regulations, 2014 CFR

...FRUITS, VEGETABLES AND OTHER PRODUCTS 1 2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2289 Shell. Shell means the outer shell and/or the woody...

2014-01-01

39

7 CFR 51.2289 - Shell.  

Code of Federal Regulations, 2010 CFR

...FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2289 Shell. Shell means the outer shell and/or the woody...

2010-01-01

40

Ocean acidification alters the material properties of Mytilus edulis shells.  

PubMed

Ocean acidification (OA) and the resultant changing carbonate saturation states is threatening the formation of calcium carbonate shells and exoskeletons of marine organisms. The production of biominerals in such organisms relies on the availability of carbonate and the ability of the organism to biomineralize in changing environments. To understand how biomineralizers will respond to OA the common blue mussel, Mytilus edulis, was cultured at projected levels of pCO2 (380, 550, 750, 1000 µatm) and increased temperatures (ambient, ambient plus 2°C). Nanoindentation (a single mussel shell) and microhardness testing were used to assess the material properties of the shells. Young's modulus (E), hardness (H) and toughness (KIC) were measured in mussel shells grown in multiple stressor conditions. OA caused mussels to produce shell calcite that is stiffer (higher modulus of elasticity) and harder than shells grown in control conditions. The outer shell (calcite) is more brittle in OA conditions while the inner shell (aragonite) is softer and less stiff in shells grown under OA conditions. Combining increasing ocean pCO2 and temperatures as projected for future global ocean appears to reduce the impact of increasing pCO2 on the material properties of the mussel shell. OA may cause changes in shell material properties that could prove problematic under predation scenarios for the mussels; however, this may be partially mitigated by increasing temperature. PMID:25540244

Fitzer, Susan C; Zhu, Wenzhong; Tanner, K Elizabeth; Phoenix, Vernon R; Kamenos, Nicholas A; Cusack, Maggie

2015-02-01

41

Anti-Inflammatory Activity and Mechanism of a Lipid Extract from Hard-Shelled Mussel (Mytilus Coruscus) on Chronic Arthritis in Rats  

PubMed Central

The present study was designed to investigate the anti-inflammatory activity and mechanism of a lipid extract from hard-shelled mussel (Mytilus coruscus) on adjuvant-induced (AIA) and collagen-induced arthritis (CIA) in rats. AIA and CIA rats that received hard-shelled mussel lipid extract (HMLE group) at a dose of 100 mg/kg demonstrated significantly lower paw swelling and arthritic index, but higher body weight gain than those which received olive oil (control group). Similar results were found in arthritic rats that received New Zealand green-lipped mussel lipid extract (GMLE) at the same dosage. The levels of leukotriene B4 (LTB4), prostaglandin E2 (PGE2), thromboxane B2 (TXB2) in the serum, and interleukin-1? (IL-1?), IL-6, interferon-? (INF-?), tumor necrosis factor-? (TNF-?) in the ankle joint synovial fluids of HMLE group rats were significantly lower than those of control group. However, the levels of IL-4 and IL-10 in HMLE group rats were significantly higher than those in the control group. Decreased mRNA expressions of matrix metalloproteinase 1 (MMP1) and MMP13, but increased tissue inhibitor of metalloproteinase 1 (TIMP1) were observed in the knee joint synovium tissues of HMLE group rats when compared with the control group. No hepatotoxicity was observed in both HMLE and GMLE group rats. The present results indicated that HMLE had a similarly strong anti-inflammatory activity as GMLE. Such a strong efficacy could result from the suppression of inflammatory mediators (LTB4, PGE2, TXB2), pro-inflammatory cytokines (IL-1?, IL-6, INF-?, TNF-?) and MMPs (MMP1, MMP13), and the promotion of anti-inflammatory cytokines (IL-4, IL-10) and TIMPs (TIMP1) productions. PMID:24473164

Li, Guipu; Fu, Yuanqing; Zheng, Jusheng; Li, Duo

2014-01-01

42

Micromechanical properties and structural characterization of modern inarticulated brachiopod shells  

NASA Astrophysics Data System (ADS)

We investigated micromechanical properties and ultrastructure of the shells of the modern brachiopod species Lingula anatina, Discinisca laevis, and Discradisca stella with scanning electron microscopy (SEM, EDX), transmission electron microscopy (TEM) and Vickers microhardness indentation analyses. The shells are composed of two distinct layers, an outer primary layer and an inner secondary layer. Except for the primary layer in Lingula anatina, which is composed entirely of organic matter, all other shell layers are laminated organic/inorganic composites. The organic matter is built of chitin fibers, which provide the matrix for the incorporation of calcium phosphate. Amorphous calcium phosphate in the outer, primary layer and crystalline apatite is deposited into the inner, secondary layer of the shell. Apatite crystallite sizes in the umbonal region of the shell are about 50 × 50 nm, while within the valves crystallite sizes are significantly smaller, averanging 10 × 25 nm. There is great variation in hardness values between shell layers and between the investigated brachiopod species. The microhardness of the investigated shells is significantly lower than that of inorganic hydroxyapatite. This is caused by the predominantly organic material component that in these shells is either developed as purely organic layers or as an organic fibrous matrix reinforced by crystallites. Our results show that this particular fiber composite material is very efficient for the protection and the support of the soft animal tissue. It lowers the probability of crack formation and effectively impedes crack propagation perpendicular to the shell by crack-deviation mechanisms. The high degree of mechanical stability and toughness is achieved by two design features. First, there is the fiber composite material which overcomes some detrimental and enhances some advantageous properties of the single constituents, that is the softness and flexibility of chitin and the hardness and brittleness of apatite. Second, there is a hierarchical structuring from the nanometer to a micrometer level. We could identify at least seven levels of hierarchy within the shells.

Merkel, C.; Griesshaber, E.; Kelm, K.; Neuser, R.; Jordan, G.; Logan, A.; Mader, W.; Schmahl, W. W.

2007-06-01

43

Lipid Extract from Hard-Shelled Mussel (Mytilus coruscus) Improves Clinical Conditions of Patients with Rheumatoid Arthritis: A Randomized Controlled Trial  

PubMed Central

Studies have suggested a lipid extract from hard-shelled mussel (Mytilus coruscus) (HMLE) possessed strong anti-inflammatory activity in arthritis model of rats. This study investigated whether HMLE could improve clinical conditions of rheumatoid arthritis patients. Fifty rheumatoid arthritis patients (28–75 years) were randomly assigned to receive HMLE capsules or receive placebo capsules for 6 months. Forty-two subjects and 50 subjects were included in per-protocol and intention-to-treat analysis, respectively. Significant differences in changes on disease activity score (DAS28) and clinical disease activity index (CDAI) after 6-month intervention (p < 0.01) were observed in both analyses with more evident efficacy shown in per-protocol population (?DAS28 = 0.47; ?CDAI = 4.17), which favored the benefits of the HMLE group. TNF-? (tumor necrosis factor ?), interleukin (IL)-1? and PGE2 (prostaglandin E2) but not IL-6, were significantly decreased in both groups, and the decrements were much larger in the HMLE group for TNF-? and PGE2 after 6 months from baseline (p < 0.05). IL-10 was significantly increased in both groups and the change was much more evident in the HMLE group (p < 0.05). In conclusion, HMLE exhibited benefits for the clinical conditions of rheumatoid patients in relation to improvement in the balance between pro- and anti-inflammatory factors, which indicated its potential to serve as adjunctive treatment for rheumatoid arthritis. (ClinicalTrials.gov NCT02173587). PMID:25602164

Fu, Yuanqing; Li, Guipu; Zhang, Xinhua; Xing, Gengyan; Hu, Xiaojie; Yang, Lifeng; Li, Duo

2015-01-01

44

Lipid extract from hard-shelled mussel (Mytilus coruscus) improves clinical conditions of patients with rheumatoid arthritis: a randomized controlled trial.  

PubMed

Studies have suggested a lipid extract from hard-shelled mussel (Mytilus coruscus) (HMLE) possessed strong anti-inflammatory activity in arthritis model of rats. This study investigated whether HMLE could improve clinical conditions of rheumatoid arthritis patients. Fifty rheumatoid arthritis patients (28-75 years) were randomly assigned to receive HMLE capsules or receive placebo capsules for 6 months. Forty-two subjects and 50 subjects were included in per-protocol and intention-to-treat analysis, respectively. Significant differences in changes on disease activity score (DAS28) and clinical disease activity index (CDAI) after 6-month intervention (p < 0.01) were observed in both analyses with more evident efficacy shown in per-protocol population (?DAS28 = 0.47; ?CDAI = 4.17), which favored the benefits of the HMLE group. TNF-? (tumor necrosis factor ?), interleukin (IL)-1? and PGE2 (prostaglandin E2) but not IL-6, were significantly decreased in both groups, and the decrements were much larger in the HMLE group for TNF-? and PGE2 after 6 months from baseline (p < 0.05). IL-10 was significantly increased in both groups and the change was much more evident in the HMLE group (p < 0.05). In conclusion, HMLE exhibited benefits for the clinical conditions of rheumatoid patients in relation to improvement in the balance between pro- and anti-inflammatory factors, which indicated its potential to serve as adjunctive treatment for rheumatoid arthritis. (ClinicalTrials.gov NCT02173587). PMID:25602164

Fu, Yuanqing; Li, Guipu; Zhang, Xinhua; Xing, Gengyan; Hu, Xiaojie; Yang, Lifeng; Li, Duo

2015-01-01

45

Material with core-shell structure  

DOEpatents

Disclosed is a material having a composite particle, the composite particle including an outer shell and a core. The core is made from a lithium alloying material and the outer shell has an inner volume that is greater in size than the core of the lithium alloying material. In some instances, the outer mean diameter of the outer shell is less than 500 nanometers and the core occupies between 5 and 99% of the inner volume. In addition, the outer shell can have an average wall thickness of less than 100 nanometers.

Luhrs, Claudia (Rio Rancho, NM); Richard, Monique N. (Ann Arbor, MI); Dehne, Aaron (Maumee, OH); Phillips, Jonathan (Rio Rancho, NM); Stamm, Kimber L. (Ann Arbor, MI); Fanson, Paul T. (Brighton, MI)

2011-11-15

46

Limits on a radio shell around the Crab Nebula  

Microsoft Academic Search

A search at radio wavelengths for the hypothetical outer shell of the Crab Nebula is reported, and no shell has been detected. It is indicated that such a shell is fainter than expected for the surface brightness-linear diameter relation for shell type supernova remnants. Alternative explanations for the optical shell include emission from the hypothetical remnant shell, light scattered off

A. S. Wilson; K. W. Weiler

1982-01-01

47

46 CFR 154.170 - Outer hull steel plating.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Outer hull steel plating. 154.170 Section 154.170...Hull Structure § 154.170 Outer hull steel plating. (a) Except as required in...paragraph (b) of this section, the outer hull steel plating, including the shell and...

2013-10-01

48

46 CFR 154.170 - Outer hull steel plating.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Outer hull steel plating. 154.170 Section 154.170...Hull Structure § 154.170 Outer hull steel plating. (a) Except as required in...paragraph (b) of this section, the outer hull steel plating, including the shell and...

2012-10-01

49

46 CFR 154.170 - Outer hull steel plating.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Outer hull steel plating. 154.170 Section 154.170...Hull Structure § 154.170 Outer hull steel plating. (a) Except as required in...paragraph (b) of this section, the outer hull steel plating, including the shell and...

2011-10-01

50

46 CFR 154.170 - Outer hull steel plating.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Outer hull steel plating. 154.170 Section 154.170...Hull Structure § 154.170 Outer hull steel plating. (a) Except as required in...paragraph (b) of this section, the outer hull steel plating, including the shell and...

2014-10-01

51

Shell forming system  

NASA Technical Reports Server (NTRS)

Hollow shells of high uniformity are formed by emitting liquid through an outer nozzle and gas through an inner nozzle, to form a hollow extrusion, by flowing the gas at a velocity between about 1.3 and 10 times the liquid velocity. The natural breakup rate of the extrusion can be increased to decrease shell size by applying periodic perturbations to one of the materials prior to exiting the nozzles, to a nozzle, or to the extrusion.

Kendall, Jr., James M. (Inventor); Wang, Taylor G. (Inventor); Elleman, Daniel D. (Inventor)

1990-01-01

52

Thick-shell nanocrystal quantum dots  

DOEpatents

Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

Hollingsworth, Jennifer A. (Los Alamos, NM); Chen, Yongfen (Eugene, OR); Klimov, Victor I. (Los Alamos, NM); Htoon, Han (Los Alamos, NM); Vela, Javier (Los Alamos, NM)

2011-05-03

53

Shell-Tile Thermal-Protection System  

NASA Technical Reports Server (NTRS)

Durable shell-tile thermal-protection system consists of interlocking upper and lower hard caps, incorporating appropriate stiffeners and enclosing lightweight fibrous insulation. New shell tile more durable than reusable surface insulation (RSI) currently used on Space Shuttle orbiter.

Macconochie, I. O.; Lowson, A. G.; Kelly, H. N.

1983-01-01

54

Gizzard and other lean mass components increase, yet Basal Metabolic Rates decrease, when red knots Calidris canutus are shifted from soft to hard-shelled food  

Microsoft Academic Search

We measured basal metabolic rate (BMR), body mass, lean mass, and gizzard mass of captive red knots Calidris canutus islandica maintained on a trout chow diet (soft- texture, low ash and water content) for several years and then shifted to small mussels Mytilus edulis (hard-texture, high ash and water content). During a 3-week period of feeding on mussels, body mass,

Theunis Piersma; James A. Gessaman; Anne Dekinga; G. Henk Visser

2004-01-01

55

Inner and outer ear anatomy  

NSDL National Science Digital Library

Sounds are actually waves from vibrations. The outer ear catches these waves and funnels them down into the inner ear. The waves reach the eardrum and in turn make the eardrum vibrate. Three small bones receive these vibrations next, then a snail shell-shaped structure called the cochlea. The cochlea is filled with liquid, and this liquid stimulates hairs inside the inner ear. The hairs transmit the signal to the auditory nerve where the signal is taken to the brain and processed as sound.

Zina Deretsky (National Science Foundation; )

2006-10-23

56

Bio-relevant dissolution testing of hard capsules prepared from different shell materials using the dynamic open flow through test apparatus.  

PubMed

Current compendial dissolution and disintegrating testing is unable to mimic physiological conditions affecting gastric drug release from immediate release dosage forms. In order to obtain more realistic data, a novel test setup was developed that we term a 'dynamic open flow through test apparatus'. It is based on the previously described dissolution stress test device and attempts to simulate the intra-gastric dissolution conditions pertinent to immediate release dosage forms administered under fasting conditions with respect to flow rates, intra-gastric temperature profiles and gastric motility. The concept of the dynamic open flow through test apparatus has been tested using five different types of hard capsules: conventional hard gelatin capsules (HGC), three hypromellose based capsules (Vcaps, Vcaps Plus and DRcaps) and pullulan based capsules (Plantcaps). These were of different sizes but all contained 100mg caffeine in each formulation, adjusted to avoid buoyancy by addition of excipient. When the capsules were stressed in the apparatus under the dynamic flow conditions applying mild pressure simulating gastric motility, release from release from Vcaps Plus, Vcaps and Plantcaps capsules was very well comparable to HGC. Capsules are usually swallowed with cold water and the temperature dependency of release from gelatin was noted as a significant factor, since heat exchange in the stomach is slow. PMID:24021609

Garbacz, Grzegorz; Cadé, Dominique; Benameur, Hassan; Weitschies, Werner

2014-06-16

57

G359.97-0.038: A Hard X-Ray Filament Associated with a Supernova Shell-Molecular Cloud Interaction  

NASA Astrophysics Data System (ADS)

We present the first high-energy X-ray (>10 keV) observations of the non-thermal filament G359.97-0.038 using the Nuclear Spectroscopic Telescope Array (NuSTAR). This filament is one of approximately 20 X-ray filaments of unknown origin located in the central 20 pc region in the Galactic Center near Sgr A*. Its NuSTAR and Chandra broadband spectrum is characterized by a single power law with ? = 1.3 ± 0.3 that extends from 2 to 50 keV, with an unabsorbed luminosity of 1.3 × 1033 erg s-1 (d/8 kpc)2 in the 2-8 keV band. Despite possessing a cometary X-ray morphology that is typical of a pulsar wind nebula (PWN) in high-resolution Chandra imaging, our spatially resolved Chandra spectral analysis found no significant spectral softening along the filament as would be expected from particle synchrotron cooling. Coincident radio emission is detected using the Very Large Array at 5.5 and 8.3 GHz. We examine and subsequently discard a PWN or magnetic flux tube as the origin of G359.97-0.038. We use broadband spectral characteristics and a morphological analysis to show that G359.97-0.038 is likely an interaction site between the shell of Sgr A East and an adjacent molecular cloud. This is supported by CS molecular line spectroscopy and the presence of an OH maser.

Nynka, Melania; Hailey, Charles J.; Zhang, Shuo; Morris, Mark M.; Zhao, Jun-Hui; Goss, Miller; Bauer, Franz E.; Boggs, Stephen E.; Craig, William W.; Christensen, Finn E.; Gotthelf, Eric V.; Harrison, Fiona A.; Mori, Kaya; Perez, Kerstin M.; Stern, Daniel; Zhang, William W.

2015-02-01

58

76 FR 3152 - Agency Information Collection Activity: 1010-NEW, Upcoming Projects Considering the Use of Outer...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Use of Outer Continental Shelf (OCS) Sand, Gravel, and Shell Resources for Coastal...respondents will submit to BOEMRE to obtain OCS sand, gravel, and shell resources for use...Information and procedures for obtaining sand, gravel, and shell resources can be...

2011-01-19

59

Diffusion, sedimentation, and rheology of concentrated suspensions of core-shell particles  

NASA Astrophysics Data System (ADS)

Short-time dynamic properties of concentrated suspensions of colloidal core-shell particles are studied using a precise force multipole method which accounts for many-particle hydrodynamic interactions. A core-shell particle is composed of a rigid, spherical dry core of radius a surrounded by a uniformly permeable shell of outer radius b and hydrodynamic penetration depth ?-1. The solvent flow inside the permeable shell is described by the Brinkman-Debye-Bueche equation, and outside the particles by the Stokes equation. The particles are assumed to interact non-hydrodynamically by a hard-sphere no-overlap potential of radius b. Numerical results are presented for the high-frequency shear viscosity, ??, sedimentation coefficient, K, and the short-time translational and rotational self-diffusion coefficients, Dt and Dr. The simulation results cover the full three-parametric fluid-phase space of the composite particle model, with the volume fraction extending up to 0.45, and the whole range of values for ?b, and a/b. Many-particle hydrodynamic interaction effects on the transport properties are explored, and the hydrodynamic influence of the core in concentrated systems is discussed. Our simulation results show that for thin or hardly permeable shells, the core-shell systems can be approximated neither by no-shell nor by no-core models. However, one of our findings is that for ?(b - a) ? 5, the core is practically not sensed any more by the weakly penetrating fluid. This result is explained using an asymptotic analysis of the scattering coefficients entering into the multipole method of solving the Stokes equations. We show that in most cases, the influence of the core grows only weakly with increasing concentration.

Abade, Gustavo C.; Cichocki, Bogdan; Ekiel-Je?ewska, Maria L.; Nägele, Gerhard; Wajnryb, Eligiusz

2012-03-01

60

Sound Transmission through Two Concentric Cylindrical Sandwich Shells  

NASA Technical Reports Server (NTRS)

This paper solves the problem of sound transmission through a system of two infinite concentric cylindrical sandwich shells. The shells are surrounded by external and internal fluid media and there is fluid (air) in the annular space between them. An oblique plane sound wave is incident upon the surface of the outer shell. A uniform flow is moving with a constant velocity in the external fluid medium. Classical thin shell theory is applied to the inner shell and first-order shear deformation theory is applied to the outer shell. A closed form for transmission loss is derived based on modal analysis. Investigations have been made for the impedance of both shells and the transmission loss through the shells from the exterior into the interior. Results are compared for double sandwich shells and single sandwich shells. This study shows that: (1) the impedance of the inner shell is much smaller than that of the outer shell so that the transmission loss is almost the same in both the annular space and the interior cavity of the shells; (2) the two concentric sandwich shells can produce an appreciable increase of transmission loss over single sandwich shells especially in the high frequency range; and (3) design guidelines may be derived with respect to the noise reduction requirement and the pressure in the annular space at a mid-frequency range.

Tang, Yvette Y.; Silcox, Richard J.; Robinson, Jay H.

1996-01-01

61

Method of fabricating nested shells and resulting product  

DOEpatents

A multiple shell structure and a method of manufacturing such structure wherein a hollow glass microsphere is surface treated in an organosilane solution so as to render the shell outer surface hydrophobic. The surface treated glass shell is then suspended in the oil phase of an oil-aqueous phase dispersion. The oil phase includes an organic film-forming monomer, a polymerization initiator and a blowing agent. A polymeric film forms at each phase boundary of the dispersion and is then expanded in a blowing operation so as to form an outer homogeneously integral monocellular substantially spherical thermoplastic shell encapsulating an inner glass shell of lesser diameter.

Henderson, Timothy M. (Ann Arbor, MI); Kool, Lawrence B. (Ann Arbor, MI)

1982-01-01

62

Method of fabricating nested shells and resulting product  

SciTech Connect

A multiple shell structure and a method of manufacturing such structure wherein a hollow glass microsphere is surface treated in an organosilane solution so as to render the shell outer surface hydrophobic. The surface treated glass shell is then suspended in the oil phase of an oil-aqueous phase dispersion. The oil phase includes an organic film-forming monomer, a polymerization initiator and a blowing agent. A polymeric film forms at each phase boundary of the dispersion and is then expanded in a blowing operation so as to form an outer homogeneously integral monocellular substantially spherical thermoplastic shell encapsulating an inner glass shell of lesser diameter.

Henderson, T.M.; Kool, L.B.

1982-04-27

63

hard-core 1st shell  

E-print Network

: unveiling the rules of collec7ve animal behavior A Cavagna, A Cimarelli, I Giardina, A Procaccini Arxiv preprint arXiv:0802.1674312008 Interac7on ruling animal collec7ve behavior, 1491-1510 Large-scale behaviour in animal groups A Cavagna, I Giardina

Turner, Matthew

64

Turbine blade with spar and shell  

DOEpatents

A turbine blade with a spar and shell construction in which the spar and the shell are both secured within two platform halves. The spar and the shell each include outward extending ledges on the bottom ends that fit within grooves formed on the inner sides of the platform halves to secure the spar and the shell against radial movement when the two platform halves are joined. The shell is also secured to the spar by hooks extending from the shell that slide into grooves formed on the outer surface of the spar. The hooks form a serpentine flow cooling passage between the shell and the spar. The spar includes cooling holes on the lower end in the leading edge region to discharge cooling air supplied through the platform root and into the leading edge cooling channel.

Davies, Daniel O. (Palm City, FL); Peterson, Ross H. (Loxahatchee, FL)

2012-04-24

65

Saturn's outer magnetosphere  

NASA Technical Reports Server (NTRS)

Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like Earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc.

Schardt, A. W.; Behannon, K. W.; Carbary, J. F.; Eviatar, A.; Lepping, R. P.; Siscoe, G. L.

1983-01-01

66

DIFFUSION OF PROTONS IN THE OUTER RADIATION BELT  

Microsoft Academic Search

The diffusion of protons in the outer radiation belt due to violation of the third adiabatic invariant has been examined. The particular mechanism studied is one in which variations in the intensity of the solar wind produce magnetic disturbances causing motion of particles between L shells. A Fokker-Planck diffusion equation is used with terms describing Coulomb energy degradation and charge-exchange

M. P. Nakada; G. D. Mead

1965-01-01

67

Law in Outer Space.  

ERIC Educational Resources Information Center

Provides an overview of the current practice and fascinating future of legal issues involved in outer space exploration and colonization. Current space law, by necessity, addresses broad principles rather than specific incidents. Nonetheless, it covers a variety of issues including commercial development, rescue agreements, object registration,…

Schmidt, William G.

1997-01-01

68

Lunch in Outer Space!  

NSDL National Science Digital Library

Students learn about the unique challenges astronauts face while eating in outer space. They explore different food choices and food packaging. Students learn about the engineering design process, and then, as NASA engineering teams, they design and build original model devices to help astronauts eat in a microgravity environment --- their own creative devices for food storage and meal preparation.

Integrated Teaching and Learning Program,

69

Mining outer space  

Microsoft Academic Search

The need to develop new mineral resources as terrestrial supplies are depleted could lead to mining efforts in outer space, where other bodies can be found with materials similar to those of the earth. The high cost of direct sampling requires that earth-based observations be made first, followed by unmanned flights and landing missions. The surface composition of over 100

M. J. Gaffey; T. B. McCord

1977-01-01

70

Ionic bonding of lanthanides, as influenced by d- and f-atomic orbitals, by core-shells and by relativity.  

PubMed

Lanthanide trihalide molecules LnX3 (X = F, Cl, Br, I) were quantum chemically investigated, in particular detail for Ln = Lu (lutetium). We applied density functional theory (DFT) at the nonrelativistic and scalar and SO-coupled relativistic levels, and also the ab initio coupled cluster approach. The chemically active electron shells of the lanthanide atoms comprise the 5d and 6s (and 6p) valence atomic orbitals (AO) and also the filled inner 4f semivalence and outer 5p semicore shells. Four different frozen-core approximations for Lu were compared: the (1s(2) -4d(10) ) [Pd] medium core, the [Pd+5s(2) 5p(6) = Xe] and [Pd+4f(14) ] large cores, and the [Pd+4f(14) +5s(2) 5p(6) ] very large core. The errors of Lu?X bonding are more serious on freezing the 5p(6) shell than the 4f(14) shell, more serious upon core-freezing than on the effective-core-potential approximation. The Ln?X distances correlate linearly with the AO radii of the ionic outer shells, Ln(3+) -5p(6) and X(-) -np(6) , characteristic for dominantly ionic Ln(3+) -X(-) binding. The heavier halogen atoms also bind covalently with the Ln-5d shell. Scalar relativistic effects contract and destabilize the Lu?X bonds, spin orbit coupling hardly affects the geometries but the bond energies, owing to SO effects in the free atoms. The relativistic changes of bond energy BE, bond length Re , bond force k, and bond stretching frequency vs do not follow the simple rules of Badger and Gordy (Re ?BE?k?vs ). The so-called degeneracy-driven covalence, meaning strong mixing of accidentally near-degenerate, nearly nonoverlapping AOs without BE contribution is critically discussed. © 2015 Wiley Periodicals, Inc. PMID:25565146

Ji, Wen-Xin; Xu, Wei; Schwarz, W H Eugen; Wang, Shu-Guang

2015-03-15

71

Biomineral repair of abalone shell apertures.  

PubMed

The shell of the gastropod mollusc, abalone, is comprised of nacre with an outer prismatic layer that is composed of either calcite or aragonite or both, depending on the species. A striking characteristic of the abalone shell is the row of apertures along the dorsal margin. As the organism and shell grow, new apertures are formed and the preceding ones are filled in. Detailed investigations, using electron backscatter diffraction, of the infill in three species of abalone: Haliotis asinina, Haliotis gigantea and Haliotis rufescens reveals that, like the shell, the infill is composed mainly of nacre with an outer prismatic layer. The infill prismatic layer has identical mineralogy as the original shell prismatic layer. In H. asinina and H. gigantea, the prismatic layer of the shell and infill are made of aragonite while in H. rufescens both are composed of calcite. Abalone builds the infill material with the same high level of biological control, replicating the structure, mineralogy and crystallographic orientation as for the shell. The infill of abalone apertures presents us with insight into what is, effectively, shell repair. PMID:23707541

Cusack, Maggie; Guo, Dujiao; Chung, Peter; Kamenos, Nicholas A

2013-08-01

72

Outer Solar System Exploration  

E-print Network

are similar to Uranus and Neptune #12;Oh the Places we'll Go · The outer solar system is target-rich. We'd like to learn more about volcanoes on Io, storms on Titan, the rings around Uranus and whether Ariel ocean and how to access it in the future ­ Uranus orbiter, to study an ice giant in our own solar system

Rathbun, Julie A.

73

Exploring the outer planets  

NASA Technical Reports Server (NTRS)

Initial, current and planned United States projects for the spacecraft exploration of the outer planets of the solar system are presented. Initial plans were developed in the mid-1960's for the exploration of the outer planets by utilizing the gravity-assist technique during a fortuitous alignment of the outer planets in the Grand Tour Project, however although state-of-the-art space technology could have supported the project, it was considered too expensive, therefore politically infeasible. Subsequently, the Pioneer Project was undertaken to explore the asteroid belt and the environment around Jupiter and the Voyager Project was undertaken to send two spacecraft to fly by Jupiter and utilize its gravity assist to reach Saturn. The successful Pioneer 10 and 11 missions have provided important information on the effects of the asteroid belt and the severe radiation environment around Jupiter, and Voyager 1 has collected information about Jupiter, its magnetic fields and radiation zones, and its satellites. Project Galileo is intended to be launched in January 1982 to conduct an intensive investigation of Jupiter, its satellites and immediate environment and a Saturn Orbiter dual probe mission and a Uranus orbiter are also under consideration.

Parks, R. J.

1979-01-01

74

Snail Shell  

USGS Multimedia Gallery

Plant seems to be a Heliotropum sp. Huge snail shells litter the wetland around Asuncion Bay. Near 25°15’49’’S, 57°37’47’’W. La plantita detrás del caracol parece ser un Heliotropium sp., Boraginaceae....

75

Shelled opisthobranchs.  

PubMed

In his contributions to the monographic series "Manual of Conchology", Henry Pilsbry reviewed the subgroup Tectibranchiata, comprising those opisthobranch snails that (at least primitively) still possess a shell (Pilsbry, 1894-1896). Exemplified by the Cephalaspidea (bubble shells), others included in this group at Pilsbry's time and since were Anaspidea (sea hares) and the shelled members of Notaspidea (side-gilled slugs) and Sacoglossa (leaf slugs). Pilsbry (and others since his time) considered tectibranchs to be the "root stock" from which more advanced gastropods such as Nudibranchia and Pulmonata were derived. Tectibranch systematics is firmly based on conchology and most species were originally described from empty shells. However, soft-anatomical characters were acknowledged quite early on as equally important in tectibranchs, due to the reduction of their shells and their evolutionary proximity to unshelled gastropods. Today, Tectibranchiata is not recognized as a natural taxon although the word "tectibranch" (like "prosobranch" and "mesogastropod") continues in vernacular use. Shelled opisthobranchs have been redistributed among various taxa, including several new ones--the unresolved basal opisthobranchs (Architectibranchia) and the "lower Heterobranchia", an enigmatic and currently much-studied group of families considered basal to all of Euthyneura (Opisthobranchia and landsnails (Pulmonata)). Despite their polyphyletic status, shelled opisthobranchs remain important subjects in evolutionary studies of gastropods--as the most basal members of nearly every opisthobranch clade and as organisms with mosaic combinations of primitive and derived features within evolutionary "trends" (e.g., loss of the shell, detorsion, concentration of the nervous system, ecological specialization, etc.). Although they play a pivotal role, the shelled opisthobranchs have received minimal attention in more comprehensive gastropod studies, often relegated to token representatives at the derived end of prosobranchs or at the basal end of nudibranchs. The choice of this representative in a larger study is critical if its morphology and/or molecules are to adequately exemplify a larger group. This review explores the shelled opisthobranchs, including their history, current status and presumed synapomorphies, and emphasizes the importance of anatomical data to our current understanding of these "transitional" forms. A synthetic phylogenetic analysis, based on a combination of characters used in four published phylogenies involving tectibranchs, shows the current state of our knowledge and emphasizes areas for future study. The results indicate that Opisthobranchia, Cephalaspidea and Sacoglossa are monophyletic taxa, and that Acteon, the traditional basal opisthobranch, is convincingly a lower heterobranch. In most of the resulting cladograms, Anaspidea formed a monophyletic group with Cephalaspidea, as did pleurobranchoidean Notaspidea with Nudibranchia (the latter recently named as Nudipleura Wägele and Willan, 2000). PMID:12094725

Mikkelsen, Paula M

2002-01-01

76

Outer Solar System Nomenclature  

NASA Technical Reports Server (NTRS)

The Principal Investigator's responsibilities on this grant fell into two categories according to his participation. In the nomenclature work of the International Astronomical Union (IAU). Owen is chair of the Task Group for the Outer Solar System. He is also a member of the IAU's Working Group on Planetary and Satellite Nomenclature (WGPSN) which is composed of the chairs of the several Task Groups plus the presidents of two IAU Commissions and several outside consultants. The WGPSN is presided over by its President, Professor Kaare Aksnes from the Rosseland Institute for Theoretical Astrophysics in Oslo, Norway.

Owen, Tobias C.

1998-01-01

77

The ultimate step towards a tailored engineering of core@shell and core@shell@shell nanoparticles  

NASA Astrophysics Data System (ADS)

Complex core@shell and core@shell@shell nanoparticles are systems that combine the functionalities of the inner core and outer shell materials together with new physico-chemical properties originated by their low (nano) dimensionality. Such nanoparticles are of prime importance in the fast growing field of nanotechnology as building blocks for more sophisticated systems and a plethora of applications. Here, it is shown that although conceptually simple a modified gas aggregation approach allows the one-step generation of well-controlled complex nanoparticles. In particular, it is demonstrated that the atoms of the core and the shell of the nanoparticles can be easily inverted, avoiding intrinsic constraints of chemical methods.Complex core@shell and core@shell@shell nanoparticles are systems that combine the functionalities of the inner core and outer shell materials together with new physico-chemical properties originated by their low (nano) dimensionality. Such nanoparticles are of prime importance in the fast growing field of nanotechnology as building blocks for more sophisticated systems and a plethora of applications. Here, it is shown that although conceptually simple a modified gas aggregation approach allows the one-step generation of well-controlled complex nanoparticles. In particular, it is demonstrated that the atoms of the core and the shell of the nanoparticles can be easily inverted, avoiding intrinsic constraints of chemical methods. Electronic supplementary information (ESI) available: 1: Scheme illustrating the different strategies to grow nanoparticles with controlled chemical composition and structure. 2: Examples of TEM results on Ag@Au nanoparticles. 3: Magnetic measurements results on Co@Au and Au@Co nanoparticles. See DOI: 10.1039/c4nr02913e

Llamosa, D.; Ruano, M.; Martínez, L.; Mayoral, A.; Roman, E.; García-Hernández, M.; Huttel, Y.

2014-10-01

78

Energetic particle drift motions in the outer dayside magnetosphere  

SciTech Connect

Models of the geomagnetic field predict that within a distance of approximately one earth radius inside the dayside magnetopause, magnetic fields produced by the Chapman-Ferraro magnetopause currents create high-latitude minimum-B ''pockets'' in the geomagnetic field. Drift-shell branching caused by the minimum-B pockets is analyzed and interpreted in terms of an adiabatic shell branching and rejoining process. We examine the shell-branching process for a static field in detail, using the Choe-Beard 1974 magnetospheric magnetic field model. We find that shell branching annd rejoining conserves the particle mirror field B/sub M/, the fieldline integral invariant I, and the directional electron flux j. We determine the spatial extent of the stable trapping regions for the Choe-Beard model. We develop an adiabatic branching map methodology which completely identifies and describes the location of shell-branching points and the adiabatic trajectories of particles on branched shells, for any model field. We employ the map to develop synthetic pitch angle distributions near the dayside magnetopause by adiabatically transforming observed midnight distributions to the dayside. We find that outer dayside lines contain particles moving on branched and unbranched shells, giving rise to distinctive pitch angle distribution features. We find a good correlation between the pitch angles which mark the transition from branched to unbranched shells in the model, and the distinctive features of the OGO-5 distributions. In the morning sector, we observe large flux changes at critical pitch angles which correspond to B-pocket edges in the model. Measurements on inbound passes in the afternoon sector show first the adiabatic particle shadow, then the arrival of fluxes on rejoined shells, then fluxes on unbranced shells - in accord with model predictions. 204 refs., 138 figs., 2 tabs.

Buck, R.M.

1987-12-01

79

The microindentation behavior of several mollusk shells  

SciTech Connect

An investigation of the relationship between structure and mechanical behavior is reported for mollusk shells employing foliated, nacreous, and crossed-lamellar structures by microindentation in the Knoop and Vickers geometries. Indentation damage zones develop crack systems that reflect the micro-architecture. For the crosed-lamellar structure, the system of cracks about the indentation normally developed in a brittle material is suppressed. Previous reports that shells are harder than the corresponding minerals, calcite and aragonite, are confirmed, but it is found that this effect can be strongly dependent on orientation. This anomalous hardness is not an artifact of the indentation test technique, since scratch tests confirm the relative hardness of shell over the mineral. It is suggested that microstructural organization is of central importance in producing this hardness, as opposed to intrinsic properties of the mineral or matrix phases. 17 refs., 6 figs., 1 tab.

Laraia, V.J.; Heuer, A.H. (Case Western Reserve Univ., Cleveland, OH (USA). Dept. of Materials Science and Engineering)

1990-01-01

80

Inner and outer beauty.  

PubMed

Symmetry and pattern are precious forms of beauty that can be appreciated on both the macroscopic and molecular scales. Crystallographers have long appreciated the intimate connections between symmetry and molecular structure, reflected in their appreciation for the artwork of Escher. This admiration has been applied in the design of highly symmetrical coordination compounds. Two classes of materials are discussed: extended coordination arrays and discrete supramolecular assemblies. Extended coordination polymers have been implemented in gas separation and storage due to the remarkably porosity of these materials, aided by the ability to design ever-larger inner spaces within these frameworks. In the case of discrete symmetrical structures, defined inner and outer space present a unique aesthetic and chemical environment. The consequent host-guest chemistry and applications in catalysis are discussed. PMID:22076081

Raymond, Kenneth N; Brown, Casey J

2012-01-01

81

Saturn's outer satellite - Phoebe  

NASA Technical Reports Server (NTRS)

Voyager 2 took these images of Saturn's outer satellite Phoebe, on Sept. 4, 1981, from 2.2 million kilometers (1.36 million miles)away. This pair shows two different hemispheres of the satellite. The left image shows a bright mountain on the upper right edge reflecting the light of the setting sun. This mountain is possibly the central peak of a large impact crater taking up most of the upper right quadrant of Phoebe in this view. The right images shows a hemisphere with an intrinsically bright spot in the top portion of the image as well as the ridges appearing bright in the sunset light of the lower right. These images were processed by the Multimission Image Processing Laboratory of the Jet Propulsion Laboratory. The Jet Propulsion Laboratory manages the Voyager Project for NASA's Office of Space Science and Applications.

1999-01-01

82

LHCb outer tracker prototypes  

E-print Network

This note describes measurements performed on various prototype modules of LHCb Outer Tracker drift chambers in the test beam periods of 1998 and 1999. Presented are measurements of various drift cell characteristics. The single cell efficiency is shown to be better than 98%. The gas mixture Ar:CF4:CO2 (68:27:05) in a 5 mm straw tube is just fast enough to keep the maximum drift time within two LHC bunch crossings. It is shown that 8 mm cells do not satisfy this criterium. The noise in the tested 5 mm prototypes is below 0.2%, the main source of this noise is the amplifier/shaper. Next to presenting the measurements, the test beam setup is described. Furthermore a description is given of the used analysis methods. The same methods will be used to analyse the data taken in 2000. This data will be reported in a seperate note.

Van der Eijk, R

2000-01-01

83

The leptospiral outer membrane.  

PubMed

The outer membrane (OM) is the front line of leptospiral interactions with their environment and the mammalian host. Unlike most invasive spirochetes, pathogenic leptospires must be able to survive in both free-living and host-adapted states. As organisms move from one set of environmental conditions to another, the OM must cope with a series of conflicting challenges. For example, the OM must be porous enough to allow nutrient uptake, yet robust enough to defend the cell against noxious substances. In the host, the OM presents a surface decorated with adhesins and receptors for attaching to, and acquiring, desirable host molecules such as the complement regulator, Factor H.Factor H. On the other hand, the OM must enable leptospires to evade detection by the host's immune system on their way from sites of invasion through the bloodstream to the protected niche of the proximal tubule. The picture that is emerging of the leptospiral OM is that, while it shares many of the characteristics of the OMs of spirochetes and Gram-negative bacteria, it is also unique and different in ways that make it of general interest to microbiologists. For example, unlike most other pathogenic spirochetes, the leptospiral OM is rich in lipopolysaccharide (LPS). Leptospiral LPS is similar to that of Gram-negative bacteria but has a number of unique structural features that may explain why it is not recognized by the LPS-specific Toll-like receptor 4 of humans. As in other spirochetes, lipoproteins are major components of the leptospiral OM, though their roles are poorly understood. The functions of transmembrane outer membrane proteins (OMPs) in many cases are better understood, thanks to homologies with their Gram-negative counterparts and the emergence of improved genetic techniques. This chapter will review recent discoveries involving the leptospiral OM and its role in leptospiral physiology and pathogenesis. PMID:25388136

Haake, David A; Zückert, Wolfram R

2015-01-01

84

CORNER OF SUBPILE ROOM: NORTH AND EAST SIDES. STEEL OUTER ...  

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

CORNER OF SUBPILE ROOM: NORTH AND EAST SIDES. STEEL OUTER SHELL HAS BEEN AFFIXED. SIGN SAYS "HERRICK IRON WORKS STEEL, OAKLAND, CALIFORNIA." NOTE CONDUIT FOR FUTURE INSTRUMENTATION. TOP OF STEEL CASE WILL BE LEVEL WITH BASEMENT CEILING. CAMERA FACES SOUTHEAST. INL NEGATIVE NO. 734. Unknown Photographer, 10/6/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

85

Strategy for outer planets exploration  

NASA Technical Reports Server (NTRS)

NASA's Planetary Programs Office formed a number of scientific working groups to study in depth the potential scientific return from the various candidate missions to the outer solar system. The results of these working group studies were brought together in a series of symposia to evaluate the potential outer planet missions and to discuss strategies for exploration of the outer solar system that were consistent with fiscal constraints and with anticipated spacecraft and launch vehicle capabilities. A logical, scientifically sound, and cost effective approach to exploration of the outer solar system is presented.

1975-01-01

86

Vibration of Shells  

NASA Technical Reports Server (NTRS)

The vibrational characteristics and mechanical properties of shell structures are discussed. The subjects presented are: (1) fundamental equations of thin shell theory, (2) characteristics of thin circular cylindrical shells, (3) complicating effects in circular cylindrical shells, (4) noncircular cylindrical shell properties, (5) characteristics of spherical shells, and (6) solution of three-dimensional equations of motion for cylinders.

Leissa, A. W.

1973-01-01

87

Shell worlds  

NASA Astrophysics Data System (ADS)

The traditional concept of terraforming assumes ready availability of candidate planets with acceptable qualities: orbiting a star in its "Goldilocks zone", liquid water, enough mass, years longer than days, magnetic field, etc. But even stipulating affordable interstellar travel, we still might never find a good candidate elsewhere. Whatever we found likely would require centuries of heavy terraforming, just as Mars or Venus would here. Our increasing appreciation of the ubiquity of life suggests that any terra nova would already possess it. We would then face the dilemma of introducing alien life forms (us, our microbes) into another living world. Instead, we propose a novel method to create habitable environments for humanity by enclosing airless, sterile, otherwise useless planets, moons, and even large asteroids within engineered shells, which avoids the conundrum. These shells are subject to two opposing internal stresses: compression due to the primary's gravity, and tension from atmospheric pressure contained inside. By careful design, these two cancel each other resulting in zero net shell stress. Beneath the shell an Earth-like environment could be created similar in almost all respects to that of Home, except for gravity, regardless of the distance to the sun or other star. Englobing a small planet, moon, or even a dwarf planet like Ceres, would require astronomical amounts of material (quadrillions of tons) and energy, plus a great deal of time. It would be a quantum leap in difficulty over building Dyson Dots or industrializing our solar system, perhaps comparable to a mission across interstellar space with a living crew within their lifetime. But when accomplished, these constructs would be complete (albeit small) worlds, not merely large habitats. They could be stable across historic timescales, possibly geologic. Each would contain a full, self-sustaining ecology, which might evolve in curious directions over time. This has interesting implications for SETI as well.

Roy, Kenneth I.; Kennedy, Robert G., III; Fields, David E.

2013-02-01

88

Method to produce large, uniform hollow spherical shells  

DOEpatents

The invention is a method to produce large uniform hollow spherical shells by (1) forming uniform size drops of heat decomposable or vaporizable material, (2) evaporating the drops to form dried particles, (3) coating the dried particles with a layer of shell forming material and (4) heating the composite particles to melt the outer layer and to decompose or vaporize the inner particle to form an expanding inner gas bubble. The expanding gas bubble forms the molten outer layer into a shell of relatively large diameter. By cycling the temperature and pressure on the molten shell, nonuniformities in wall thickness can be reduced. The method of the invention is utilized to produce large uniform spherical shells, in the millimeter to centimeter diameter size range, from a variety of materials and of high quality, including sphericity, concentricity and surface smoothness, for use as laser fusion or other inertial confinement fusion targets as well as other applications.

Hendricks, C.D.

1983-09-26

89

Acute Zonal Occult Outer Retinopathy  

Microsoft Academic Search

Acute zonal occult outer retinopathy (AZOOR) is a rare unilateral or bilateral disease of unknown etiology characterized by focal degeneration of photoreceptors. A total of 131 cases of AZOOR (205 eyes), including the variant known as acute annular outer retinopathy, have been reported in the English language literature. In this group of predominantly white individuals, average age at presentation was

Dinelli M. Monson; Justine R. Smith

2011-01-01

90

Monte Carlo simulations of nematic and chiral nematic shells  

NASA Astrophysics Data System (ADS)

We present a systematic Monte Carlo simulation study of thin nematic and cholesteric shells with planar anchoring using an off-lattice model. The results obtained using the simple model correspond with previously published results for lattice-based systems, with the number, type, and position of defects observed dependent on the shell thickness with four half-strength defects in a tetrahedral arrangement found in very thin shells and a pair of defects in a bipolar (boojum) configuration observed in thicker shells. A third intermediate defect configuration is occasionally observed for intermediate thickness shells, which is stabilized in noncentrosymmetric shells of nonuniform thickness. Chiral nematic (cholesteric) shells are investigated by including a chiral term in the potential. Decreasing the pitch of the chiral nematic leads to a twisted bipolar (chiral boojum) configuration with the director twist increasing from the inner to the outer surface.

Wand, Charlie R.; Bates, Martin A.

2015-01-01

91

IMPROVEMENT EFFECT OF PLAYGROUND SURFACE BY WASTE CRUSHED SHELL MIXING  

NASA Astrophysics Data System (ADS)

If sandy soil with appropriate gradation is compacted, hard and dense ground will be generated. Even if the soil material is hard enough against shock load, the permeability of the soil decreases significantly. This paper examines the improvement effect of playground surface by waste crushed shell mixing technique. The following conclusions are obtained from the present study: 1. The maximum dry density of the sandy soil increases gradually by mixing the crushed shell. However, if the crushed shell is put into the soil too much, the density decreases conversely. 2. Although the density of the soil sample becomes high by mixing the crushed shell, the coefficient of permeability increases. 3. The soil particles once attached to the shell is not washed away easily. 4. The crushed shell doesn't change the quality of groundwater so much. 5. This repair method is applicable to improvement of playground surface.

Shigematsu, Hiroaki; Oda, Kenichi; Higuchi, Emiko; Takano, Morihiro; Tasaki, Hiroshi

92

Characterization of 12 cm Diameter Triple-shell Gas Puff Z-pinch Loads  

Microsoft Academic Search

To mitigate the Rayleigh-Taylor instability and thus increase the x-ray yield, shell-on-shell gas puff loads have been studied on high current z-pinch drivers such as Double-EAGLE, DQ and Z. A triple-shell gas puff has been developed, where a gas jet is introduced in the center and the outer and inner gas shell radii are 5.5 and 2.5 cm, respectively. We

Niansheng Qi; Jeff Banister; Sophie Chantrenne; Bruce Failor; Jerry Levine; Paul Steen; Henry Sze; Yuanxu Song

2003-01-01

93

Waste Package Outer Barrier Stress Due to Thermal Expansion with Various Barrier Gap Sizes  

SciTech Connect

The objective of this activity is to determine the tangential stresses of the outer shell, due to uneven thermal expansion of the inner and outer shells of the current waste package (WP) designs. Based on the results of the calculation ''Waste Package Barrier Stresses Due to Thermal Expansion'', CAL-EBS-ME-000008 (ref. 10), only tangential stresses are considered for this calculation. The tangential stresses are significantly larger than the radial stresses associated with thermal expansion, and at the WP outer surface the radial stresses are equal to zero. The scope of this activity is limited to determining the tangential stresses the waste package outer shell is subject to due to the interference fit, produced by having two different shell coefficients of thermal expansions. The inner shell has a greater coefficient of thermal expansion than the outer shell, producing a pressure between the two shells. This calculation is associated with Waste Package Project. The calculations are performed for the 21-PWR (pressurized water reactor), 44-BWR (boiling water reactor), 24-BWR, 12-PWR Long, 5 DHLW/DOE SNF - Short (defense high-level waste/Department of Energy spent nuclear fuel), 2-MCO/2-DHLW (multi-canister overpack), and Naval SNF Long WP designs. The information provided by the sketches attached to this calculation is that of the potential design for the types of WPs considered in this calculation. This calculation is performed in accordance with the ''Technical Work Plan for: Waste Package Design Description for SR (Ref.7). The calculation is documented, reviewed, and approved in accordance with AP-3.12Q, Calculations (Ref.1).

M. M. Lewis

2001-11-27

94

Thermoelectric Outer Planets Spacecraft (TOPS)  

NASA Technical Reports Server (NTRS)

The research and advanced development work is reported on a ballistic-mode, outer planet spacecraft using radioisotope thermoelectric generator (RTG) power. The Thermoelectric Outer Planet Spacecraft (TOPS) project was established to provide the advanced systems technology that would allow the realistic estimates of performance, cost, reliability, and scheduling that are required for an actual flight mission. A system design of the complete RTG-powered outer planet spacecraft was made; major technical innovations of certain hardware elements were designed, developed, and tested; and reliability and quality assurance concepts were developed for long-life requirements. At the conclusion of its active phase, the TOPS Project reached its principal objectives: a development and experience base was established for project definition, and for estimating cost, performance, and reliability; an understanding of system and subsystem capabilities for successful outer planets missions was achieved. The system design answered long-life requirements with massive redundancy, controlled by on-board analysis of spacecraft performance data.

1973-01-01

95

The Double Chooz Outer Veto  

NASA Astrophysics Data System (ADS)

Double Chooz is unique among reactor neutrino experiments for its Outer Veto -- a multi-layered plastic scintillator strip muon detector. The far detector Outer Veto covers 95,^2 on top of the main detector volumes and is composed of 44 modules, each made up of 64 scintillator strips outfitted with wavelength-shifting fibers coupled to a multi-anode PMT. The Outer Veto serves two purposes: first, as a veto, it reduces muon-induced backgrounds to the neutrino signal, in particular the fast neutron and stopping muon backgrounds; second, the high-quality muon tracking it provides allows for detailed studies of these backgrounds, as well as long-lived backgrounds, which cannot be vetoed, such as ^9Li and ^8He. I will describe the design of the Outer Veto, its performance, and some background studies.

Conover, Emily

2013-04-01

96

Outer planet satellite ephemeris development.  

NASA Technical Reports Server (NTRS)

Discussion of the possible effectiveness of an earth-based ephemeris development program for the outer planet natural satellites. Technologies for obtaining and reducing photographic plates are available and new satellite theories needed for data processing are being developed. It is shown that satellite ephemeris accuracies could be reduced to hundreds of km by the end of the 1970s. An earth-based program would have great benefits to future outer planet missions requiring this level of accuracy.

Duxbury, T. C.; Ananda, M. P.

1972-01-01

97

Role of bioerosion in taphonomy: effect of predatory drillholes on preservation of mollusc shells  

Microsoft Academic Search

Although bioerosion is recognized as causing significant destruction of hard substrates, few studies have assessed loss of\\u000a hard substrates by taphonomic bias against shells with predatory borings (the trace fossil Oichnus). Results of point-load compression experiments suggest preferential loss of Oichnus-bearing shells; however, studies of drilling predation often assume lack of taphonomic bias against drilled shells.This project\\u000a tested the hypothesis

Patricia H. Kelley

98

Role of reactant transport in determining the properties of NIF shells made by interfacial polycondensation  

SciTech Connect

Polymer shells up to 2 mm in diameter were prepared using an interfacial polycondensation / cross-linking reaction occurring at the surface of an oil drop. The oil phase is comprised of a solution (20 wt% or less) of isophthaloyl dichloride (IPC) dissolved in an organic solvent. An interfacial reaction is initiated when the IPC-loaded oil drop is submerged in an aqueous solution of poly(p-vinylphenol) (PVP), a poly(electrolyte) at elevated pH. Composition, structure, and surface finish for fully-formed dry shells were assessed using a number of techniques including scanning electron microscopy (SEM), atomic force microscopy (AFM), fourier-transform infrared spectroscopy (FTIR), pyrolysis-gas chromatography (GC) mass spectroscopy (MS), microhardness measurements, gas permeability, and solvent permeability measurements. From deposition rate data, a reaction mechanism and key reaction parameters were identified. The deposition rate of shell membrane material was found to be a diffusion limited reaction of IPC through the forming membrane to the exterior shell interface (which is believed to be the reaction front). The final thickness of the film deposited at the interface and the rate of deposition were found to be strong functions of the IPC concentration and oil phase solvent. Films made with diethyl phthalate (DEP) were thinner and harder than films made using 1,6-dichlorohexane (DCH) as a solvent. Differences in solubility of the forming membrane in DCH and DEP appear to be able to account for the differences in deposition rate and the hardness (related to cross-linking density). The deposition can be thought of as a phase separation which is affected by both the poly(electrolyte) / ionomer transition and the amount of cross-linking. Finally, it was found that the choice of oil phase solvent profoundly affects the evolution of the outer surface roughness.

Hamilton, K.E.; Letts, S.A.; Buckley, S.R.; Fearon, E.M.; Wilemski, G.; Cook, R.C. [Lawrence Livermore National Lab., CA (United States); Schroen-Carey, D. [W.J. Schafer and Associates, Livermore, CA (United States)

1997-03-01

99

Nanorod and nanoparticle shells in concentration gradient core-shell lithium oxides for rechargeable lithium batteries.  

PubMed

The structure, electrochemistry, and thermal stability of concentration gradient core-shell (CGCS) particles with different shell morphologies were evaluated and compared. We modified the shell morphology from nanoparticles to nanorods, because nanorods can result in a reduced surface area of the shell such that the outer shell would have less contact with the corrosive electrolyte, resulting in improved electrochemical properties. Electron microscopy studies coupled with electron probe X-ray micro-analysis revealed the presence of a concentration gradient shell consisting of nanoparticles and nanorods before and after thermal lithiation at high temperature. Rietveld refinement of the X-ray diffraction data and the chemical analysis results showed no variations of the lattice parameters and chemical compositions of both produced CGCS particles except for the degree of cation mixing (or exchange) in Li and transition metal layers. As anticipated, the dense nanorods present in the shell gave rise to a high tap density (2.5 g?cm(-3) ) with a reduced pore volume and surface area. Intimate contact among the nanorods is likely to improve the resulting electric conductivity. As a result, the CGCS Li[Ni0.60 Co0.15 Mn0.25 ]O2 with the nanorod shell retained approximately 85.5% of its initial capacity over 150 cycles in the range of 2.7-4.5 V at 60?°C. The charged electrode consisting of Li0.16 [Ni0.60 Co0.15 Mn0.25 ]O2 CGCS particles with the nanorod shell also displayed a main exothermic reaction at 279.4?°C releasing 751.7?J?g(-1) of heat. Due to the presence of the nanorod shell in the CGCS particles, the electrochemical and thermal properties are substantially superior to those of the CGCS particles with the nanoparticle shell. PMID:25044175

Yoon, Sung-June; Myung, Seung-Taek; Noh, Hyung-Joo; Lu, Jun; Amine, Khalil; Sun, Yang-Kook

2014-12-01

100

Origin of Outer Solar System  

NASA Technical Reports Server (NTRS)

Our ongoing research program combines extensive deep and wide-field observations using a variety of observational platforms with numerical studies of the dynamics of small bodies in the outer solar system in order to advance the main scientific goals of the community studying the Kuiper belt and the outer solar system. These include: (1) determining the relative populations of the known classes of KBOs as well as other possible classes; ( 2 ) determining the size distributions or luminosity function of the individual populations or the Kuiper belt as a whole; (3) determining the inclinations distributions of these populations; (4) establishing the radial extent of the Kuiper belt; ( 5 ) measuring and relating the physical properties of different types of KBOs to those of other solar system bodies; and, (6) completing our systematic inventory of the satellites of the outer planets.

Holman, Matthew J.; Lindstrom, David (Technical Monitor)

2005-01-01

101

Outer Shock Interaction in Young Core-Collapse SNRs  

NASA Astrophysics Data System (ADS)

Studying the environments in which core-collapse supernovae (SNe) explode and then subsequently evolve is essential to establish the nature of the mass loss and the explosion of the progenitor star. The spatial structure of the outer shock in young core-collapse SNRs provides an opportunity to study the nature of the medium into which the remnant has been expanding. We present our X-ray study of the outer shocks in young core-collapse SNRs in our Galaxy. For Cas A and G292.0+1.8, we find that both remnants have been likely interacting with dense red supergiant winds. For other remnants with bright thermal X-ray emission from the shell, we suggest that they are interacting with pre-existing circumstellar structure. We discuss the nature of the winds and the progenitor stars.

Lee, Jae-Joon

2014-01-01

102

Shell-armored wood cobbles as a potential criterion for detrital coal deposits  

SciTech Connect

Shell-armored wood cobbles occur on detrital-peat beaches along the seaward edge of the Mississippi Delta. Shell material consists exclusively of Mulinia lateralis, a dwarf surf clam. Soft, heavy, waterlogged wood fragments are abraded and become armored by hard shells in response to wave activity on the beach. Although their preservation potential is suspect, fossilized shell-armored wood clasts would probably be recognized as a type of coal ball and might indicate an allochthonous origin for the host coal.

DiMarco, M.J.; Nummedal, D.

1986-01-01

103

Elastic properties of the composite outer hair cell wall.  

PubMed

We propose a mathematical model for analyses of the elastic properties of the wall of the outer hair cell (OHC) in the inner ear. The model reflects the properties of the major components of the OHC wall: the subsurface cisternae, the cortical lattice, the plasma membrane, and the radial pillars. The wall is treated as a composite consisting of three elastic cylindrical shells. Two inner shells, isotropic and orthotropic/ are adjacent to each other, and the outermost isotropic shell is connected to the combined inner shell by elastic springs. We derive Flugge-type equations for the composite wall and apply the model to the interpretation of the experiments with axial loading and with inflation of the OHC. We derive expressions for the axial stiffness and the wall strains measured in these experiments in terms of the elastic properties of the wall components. We also consider a conceivable experiment with torsion of the OHC and obtain relations between the torque (the axial reaction) and the angle of torsion. These solutions provide necessary information for the future determination of the OHC elastic properties. PMID:10355560

Spector, A A; Brownell, W E; Popel, A S

1998-01-01

104

Slingshot to the Outer Planets  

NSDL National Science Digital Library

Students are introduced to the engineering challenges involved with interplanetary space travel. In particular, they learn about the gravity assist or "slingshot" maneuver often used by engineers to send spacecraft to the outer planets. Using magnets and ball bearings to simulate a planetary flyby, students investigate what factors influence the deflection angle of a gravity assist maneuver.

Integrated Teaching and Learning Program,

105

Paclitaxel and suramin-loaded core\\/shell microspheres in the treatment of brain tumors  

Microsoft Academic Search

This work presents a modified method, namely coaxial electrohydrodynamic atomization, for the preparation of microspheres with distinct core\\/shell structures. This allows the encapsulation of two drugs with different characteristics in hydrophilic properties in one single step. Variation of ratios between outer flow and inner flow produces polymer microspheres with different core\\/shell ratios, and consequently results in variable release rates of

Hemin Nie; Yilong Fu; Chi-Hwa Wang

2010-01-01

106

Buoyancy Driven Convection in Rotating Spherical Shells and Its Dynamo Action  

E-print Network

Buoyancy Driven Convection in Rotating Spherical Shells and Its Dynamo Action E. Grote, F.R. Busse influences such as the distribution of buoyancy or the effect of laterally inhomogeneous boundary conditions Heidelberg 2002 #12;Buoyancy Driven Convection in Rotating Spherical Shells 13 temperature at the outer

Simitev, Radostin D

107

Magnetic properties of core/shell nanoparticles with magnetic or nonmagnetic shells  

NASA Astrophysics Data System (ADS)

In a model presented here, the effects of interparticle exchange and random magnetocrystalline anisotropy are added to the previous models of magnetization reversal for core/shell nanostructures in order to achieve better agreement with experimental data. The results from this model are compared with ones from the Stoner-Wohlfarth model in order to help us to interpret the shell thickness dependence of the coercivity in FePt/Fe3O4 core/shell nanoparticles and describe the difference between the results from the Stoner-Wohlfarth model and experimental data arising as the shell thickness increases. For magnetic shells in the FePt/Fe3O4 core/shell system, the effective coupling between particles increases with increasing shell thickness, which leads to coercivity destruction for stronger couplings. The nucleation mode penetrates from the soft phase into the hard phase when the exchange energy density is able to compete against the random anisotropy. According to the boundary conditions, in the harder regions with higher exchange stiffness, the magnetization variation should be small and so the magnetization modes should become more localized. We discuss localized and delocalized modes. The nonlocalized modes propagating in the soft phase for the non-zero shell thickness can have an effect on the quality of particle exchange interactions. In the case of nonmagnetic shells in the FePt/SiO2 core/shell system, the same model predicts a coercivity increase with increasing shell thickness. The increase in coercivity is due to the weakening of the particle coupling with the increasingly nonmagnetic shell. We present a model for exchange bias in these systems in order to interpret the coupling effects for the core and shell in the core/shell system. Chemical intermixing at the interface leads to ‘spin glass-like’ behavior of the core/shell interface which affects the strength of coupling of the core and shell spins. In the random anisotropy model there is not so much of an effect when just high anisotropy cores and we do not expect a major difference between the superparamagnetic limits predicted by the Stoner-Wohlfarth and exchange models. Considering a bulging mode to occur in the core will have an effect on the results due to the magnetization reversal mechanisms.

Sebt, S. A.; Bakhshayeshi, A.; Abolhassani, M. R.

2012-09-01

108

Strategy for exploration of the outer planets: 1986-1996  

NASA Technical Reports Server (NTRS)

Over the past decade COMPLEX has published three strategy reports which, taken together, encompass the entire planetary system and recommend a coherent program of planetary exploration. The highest priority for outer planet exploration during the next decade is intensive study of Saturn (the planet, satellites, rings, and magnetosphere) as a system. The Committee additionally recommends that NASA engage in the following supporting activities: increased support of laboratory and theoretical studies; pursuit of earth-based and earth-orbital observations; commitment to continued operation of productive spacecraft; implementation of the instrument development plan as appropriate for the outer solar system; studies of deep atmospheric probes; development of penetrators or other hard landers; development of radiation-hardened spacecraft; and development of low-thrust propulsion systems. Longer-term objectives include exploration and intensive study of: the Uranus and Neptune systems; planetology of the Galilean satellites and Titan; and the inner Jovian system.

1986-01-01

109

Turbine airfoil with a compliant outer wall  

DOEpatents

A turbine airfoil usable in a turbine engine with a cooling system and a compliant dual wall configuration configured to enable thermal expansion between inner and outer layers while eliminating stress formation in the outer layer is disclosed. The compliant dual wall configuration may be formed a dual wall formed from inner and outer layers separated by a support structure. The outer layer may be a compliant layer configured such that the outer layer may thermally expand and thereby reduce the stress within the outer layer. The outer layer may be formed from a nonplanar surface configured to thermally expand. In another embodiment, the outer layer may be planar and include a plurality of slots enabling unrestricted thermal expansion in a direction aligned with the outer layer.

Campbell, Christian X. (Oviedo, FL); Morrison, Jay A. (Oviedo, FL)

2012-04-03

110

Double Gas Puff Z-Pinch with Axial Magnetic Field for K-Shell Radiation Production  

Microsoft Academic Search

A double gas puff with a solid fill inner shell and an annular outer shell with axial magnetic field is proposed as a possible load configuration for a plasma radiation source for K-shell radiation production of high-Z materials. This load configuration is investigated in the experiments with neon gas puffs on the IMRI-5 generator (400 kA, 430 ns) and with

Alexander V. Shishlov; Rina B. Baksht; Stanislav A. Chaikovsky; Aleksey Yu. Labetsky; Vladimir I. Oreshkin; Alexander G. Rousskikh; Anatoly V. Fedunin

2002-01-01

111

Characterization of Post-mortem Shell Alteration in Aransas Bay, Texas  

E-print Network

and chipping of outer layers (Figure 4D), and cementation of sediment grains (Figure 4E). Biological alteration consisted primarily of encrustation by bryozoans (Figure 5A), barnacles (Figure 5B), serpulid worms (Figure 5C), mussels (byssal threads; Figure 5... 12 Figure 5, Images of encrusters to shells. A, Bryozoan matrix on the exterior of an Ischadium shell; B, Three barnacles on the exterior of a Crassostrea shell; C, Two serpulid worms; D; Byssal threads from a mussel; E, Three oysters cemented...

Schirm, David Edward

2013-06-04

112

Circumstellar shells resolved in IRAS survey data. II - Analysis  

NASA Technical Reports Server (NTRS)

IRAS survey data for 512 red giant stars and young planetary nebulae were processed using a computer program which fitted the data to an idealized model of a circumstellar shell. Seventy-six of these stars were found to have circumstellar shells resolved in the 60-micron survey data. Forty pct of the 76 stars are carbon stars. Thirteen are Mira variables. The evolution of these shells, involving the interaction of the expelled material with the ISM, is modeled, and the results suggest that the period during which Mira variables lose mass lasts for approximately 10 exp 5 yr. Carbon stars are found to shed mass for about 2 x 10 exp 5 yr. The expansion velocity of the outer shell for the largest shells will normally be lower by a factor of 3-5 than the expansion velocity obtained from CO observations.

Young, K.; Phillips, T. G.; Knapp, G. R.

1993-01-01

113

Modelling of the outer heliosphere  

NASA Astrophysics Data System (ADS)

The interaction of the outflowing solar wind with the local interstellar medium (LISM) is complicated by many factors--the solar wind itself is a highly dynamical medium, interstellar neutral atoms can interact with the heliospheric boundaries in a complex fashion and the solar wind can be decelerated via mass-loading associated with pick-up ions, for example. Anomalous and galactic cosmic rays besides being modulated by the solar wind, may react back on the heliospheric boundaries leading to possibly significant structural modifications. These and other factors suggest that the physics of the outer heliosphere is strongly influenced by the properties of the very LISM and is quite different from the physics of the inner heliosphere. In this talk, we will try to synthesize the many recent developments in modelling the outer heliosphere and boundaries, encompassing both local and global models. Special emphasis will be placed on identifying those aspects of the various models which have observational implications.

Zank, G. P.

1995-06-01

114

Analyzing the Structure of CoFe-Fe3O4 Core-Shell Nanoparticles by Electron Imaging and Diffraction  

E-print Network

(magnetic hard phase) and the shell (magnetic soft phase), which may lead to magnets with improved energy-shell semiconductor nanoparticles, for example, show a comprehensively improved photostability, electronic accessi between the core and the shell is favorable, but an epitaxial growth is determined by their crystal

Liu, J. Ping

115

Origin of Outer Solar System  

NASA Technical Reports Server (NTRS)

We feel that at the present moment the available theoretical models of the Kuiper belt are still in advance of the data, and thus our main task has been to conduct observational work guided by theoretical motivations. Our efforts over the past year can be divided into four categories: A) Wide-field Searches for Kuiper Belt Objects; B) Pencil-beam Searches for Kuiper Belt Objects; C) Wide-field Searches for Moons of the Outer Planets; D) Pencil-beam Searches for Faint Uranian and Neptunian Moons; E) Recovery Observations. As of April 2002, we have conducted several searches for Kuiper belt objects using large-format mosaic CCD camera on 4-meter class telescopes. In May 1999, we used the Kitt Peak 4-meter with the NOAO Mosaic camera we attempted a search for KBOs at a range of ecliptic latitudes. In addition to our wide-field searches, we have conducted three 'pencil-beam' searches in the past year. In a pencil-beam search we take repeated integrations of the same field throughout a night. After preprocessing the resulting images we shift and recombine them along a range of rates and directions consistent with the motion of KBOs. Stationary objects then smear out, while objects moving at near the shift rate appear as point sources. In addition to our searches for Kuiper belt objects, we are completing the inventory of the outer solar system by search for faint satellites of the outer planets. In August 2001 we conducted pencil beam searches for faint Uranian and Neptunian satellites at CFHT and CTIO. These searches resulted in the discover of two Neptunian and four Uranian satellite candidates. The discovery of Kuiper belt objects and outer planet satellites is of little use if the discoveries are not followed by systematic, repeated astrometric observations that permit reliable estimates of their orbits.

Holman, Matthew J.; Boyce, J. (Technical Monitor)

2003-01-01

116

Hard thermal effective action in QCD through the thermal operator  

E-print Network

Through the application of the thermal operator to the zero temperature retarded Green's functions, we derive in a simple way the well known hard thermal effective action in QCD. By relating these functions to forward scattering amplitudes for on-shell particles, this derivation also clarifies the origin of important properties of the hard thermal effective action, such as the manifest Lorentz and gauge invariance of its integrand.

Ashok Das; J. Frenkel

2007-06-01

117

Hollow Pollen Shells to Enhance Drug Delivery  

PubMed Central

Pollen grain and spore shells are natural microcapsules designed to protect the genetic material of the plant from external damage. The shell is made up of two layers, the inner layer (intine), made largely of cellulose, and the outer layer (exine), composed mainly of sporopollenin. The relative proportion of each varies according to the plant species. The structure of sporopollenin has not been fully characterised but different studies suggest the presence of conjugated phenols, which provide antioxidant properties to the microcapsule and UV (ultraviolet) protection to the material inside it. These microcapsule shells have many advantageous properties, such as homogeneity in size, resilience to both alkalis and acids, and the ability to withstand temperatures up to 250 °C. These hollow microcapsules have the ability to encapsulate and release actives in a controlled manner. Their mucoadhesion to intestinal tissues may contribute to the extended contact of the sporopollenin with the intestinal mucosa leading to an increased efficiency of delivery of nutraceuticals and drugs. The hollow microcapsules can be filled with a solution of the active or active in a liquid form by simply mixing both together, and in some cases operating a vacuum. The active payload can be released in the human body depending on pressure on the microcapsule, solubility and/or pH factors. Active release can be controlled by adding a coating on the shell, or co-encapsulation with the active inside the shell. PMID:24638098

Diego-Taboada, Alberto; Beckett, Stephen T.; Atkin, Stephen L.; Mackenzie, Grahame

2014-01-01

118

The Fabrication of Replicated Optics for Hard X-Ray Astronomy  

NASA Technical Reports Server (NTRS)

We describe the fabrication process for producing shallow-graze-angle mirrors for hard x-ray astronomy. This presentation includes the generation of the necessary super-polished mandrels, their metrology, and the subsequent mirror shell electroforming and testing.

Speegle, C. O.; Ramsey, B. D.; Engelhaupt, D.

2000-01-01

119

Formation of Gaseous Shells  

NASA Astrophysics Data System (ADS)

HI observations have revealed in several shell galaxies the presence of gaseous shells slightly displaced from the stellar shells radially, in the outward direction. We propose a mechanism to form this gaseous shells, based on the well-known phase-wrapping process of the companion matter in a merger, with nearly radial orbits. The mechanism relies on the existence of a clumpy interstellar matter, and on dynamical friction experienced by the companion core.

Combes, F.; Charmandaris, V.

120

Electrochemical characterization of a bioceramic material: The shell of the Eastern oyster Crassostrea virginica.  

PubMed

The shell of the Eastern oyster (Crassostrea virginica) is composed of multiple incongruent mineralized layers. This bioceramic composite material was investigated to determine the effects of shell thickness, orientation and layer composition on its electrochemical behavior using electrochemical impedance spectroscopy, potentiodynamic polarization and scanning electron microscopy-energy dispersive spectroscopy. SEM-EDS analysis of the oyster shell revealed that the multilayered biocomposite material is composed of calcium carbonate (CaCO(3)). EIS measurements in 3.5wt.% NaCl indicated that the impedance of the whole oyster shell in the low frequency region exhibited high impedance values which exhibited a decreasing trend with increasing immersion time. In terms of overall shell thickness, limiting currents measured by potentiodynamic techniques through the shell were observed to increase when the outer layers of the shell were sequentially removed by grinding, thus decreasing the shell thickness. These limiting current values remained relatively constant when the inner layers of the shell were removed. The impedance values of the oyster shell material as measured by EIS were shown to decrease with decreasing shell thickness. These findings suggest that the prismatic (outermost) shell layer in combination with the soluble organic matrix between all shell layers may influence the ionic conductivity through the oyster shell. PMID:21550319

Yoon, Yuhchae; Mount, Andrew S; Hansen, Karolyn M; Hansen, Douglas C

2011-06-01

121

Rockwell Hardness Measurement of  

E-print Network

960-5 Rockwell Hardness Measurement of Metallic Materials Samuel R. Low NISTrecommended p r a c t i c e g u i d e Special Publication 960-5 #12;i Rockwell Hardness Measurement of Metallic Materials: (202) 512­2250 Mail: Stop SSOP, Washington, DC 20402-0001 #12;N FOREWORD The Rockwell hardness test

Colton, Jonathan S.

122

BOOKSHELF Hard Disk Drive  

E-print Network

- widths ever higher as higher frequency disturbances become relevant. THE BOOK Hard Disk Drive Servo examples. In chapters 2­5 of Hard Disk Drive Servo Systems it is easy to forget that one is reading a book about disk drive control rather than a book on general control theory. Hard Disk Drive Servo Systems

Benmei, Chen

123

Synthesis and characterization of hard magnetic composite photocatalyst—Barium ferrite\\/silica\\/titania  

Microsoft Academic Search

Hard magnetic composite photocatalytic particles—barium ferrite (magnetic core)\\/silica (intermediate layer)\\/titania (photoactive shell) (B\\/S\\/T) were prepared by wet-chemical methods. Anatase titania nanoparticles were directly coated on the silica-coated barium ferrite forming photoactive titania shell by hydrolysis and condensation of titanium n-butoxide. The prepared hard magnetic composite photocatalyst can be magnetically fluidized and recovered by an applied magnetic field enhancing both the

Seung-woo Lee; Jack Drwiega; David Mazyck; Chang-Yu Wu; Wolfgang M. Sigmund

2006-01-01

124

Mechanical and electromotile characteristics of auditory outer hair cells.  

PubMed

The passive and active properties of the cochlear outer hair cell are studied. The outer hair cell is currently considered the major candidate for the active component of mammalian hearing. Understanding of its properties may explain the amplification and sharp frequency selectivity of the ear. To analyse the cell behaviour, a model of a nonlinear anisotropic electro-elastic shell is used. Using the data from three independent experiments, where the mechanical strains of the cell are measured, estimates of the cell wall in-plane Young's moduli and Poisson's ratios are given, as well as estimates of three modes of bending stiffness. Based on these estimates and data from the microchamber experiment, where the cell is under the action of transmembrane potential changes, the characteristics of the outer hair cell active behaviour are found. These characteristics include the coefficients of the active force production per unit of the transmembrane potential change and limiting parameters of the electromotile response for extreme hyperpolarisation and depolarisation of the cell. The obtained estimates provide important information for the modelling of organ-level cochlear mechanics. PMID:10396830

Spector, A A; Brownell, W E; Popel, A S

1999-03-01

125

Outer scale of atmospheric turbulence  

NASA Astrophysics Data System (ADS)

In the early 70's, the scientists in Italy (A.Consortini, M.Bertolotti, L.Ronchi), USA (R.Buser, Ochs, S.Clifford) and USSR (V.Pokasov, V.Lukin) almost simultaneously discovered the phenomenon of deviation from the power law and the effect of saturation for the structure phase function. During a period of 35 years we have performed successively the investigations of the effect of low-frequency spectral range of atmospheric turbulence on the optical characteristics. The influence of the turbulence models as well as a outer scale of turbulence on the characteristics of telescopes and systems of laser beam formations has been determined too.

Lukin, Vladimir P.

2005-10-01

126

Magnetospheres of the outer planets  

SciTech Connect

The magnetospheres of the outer planets have been shown by Voyager explorations to strongly interact with the surfaces and atmospheres of their planetary satellites and rings. In the cases of Jupiter, Saturn and Uranus, the processes of charged particle sputtering, neutral gas cloud formation, and rapid plasma injection from the ionization of the neutral clouds, have important implications both for the magnetospheres as a whole and for the surfaces and atmospheres of their satellites. The general methodology employed in these researches has involved comparisons of the planetary magnetospheres in order to identify common physical processes. 16 references.

Cheng, A.F.

1986-12-01

127

Manipulation of emission energy in GaAs/AlGaAs core-shell nanowires with radial heterostructure  

SciTech Connect

Photoluminescence was studied in GaAs/AlGaAs nanowires (NWs) with different radial heterostructures. We demonstrated that manipulation of the emission energy may be achieved by appropriate choice of the shell structure. The emission at highest energy is generated in the NWs with tunneling thin AlGaAs inner shell and thin GaAs outer shell due to recombination of the photoexcited electrons confined in the outer shell with the holes in the core. Lower energy emission was shown to occur in the NWs with thick outer shell grown in the form of a short-period GaAs/AlGaAs multiple quantum well structure. In this case, the tunneling probability through the multiple quantum wells controls the energy emitted by the NWs. The doping of core results in dominated low energy emission from the GaAs core.

Barbosa, B. G.; Arakaki, H.; Souza, C. A. de; Pusep, Yu. A. [Instituto de Fisica de São Carlos, Universidade de São Paulo, 13560-970 Sao Carlos, SP (Brazil)

2014-03-21

128

The pollen tube: a soft shell with a hard core.  

PubMed

Plant cell expansion is controlled by a fine-tuned balance between intracellular turgor pressure, cell wall loosening and cell wall biosynthesis. To understand these processes, it is important to gain in-depth knowledge of cell wall mechanics. Pollen tubes are tip-growing cells that provide an ideal system to study mechanical properties at the single cell level. With the available approaches it was not easy to measure important mechanical parameters of pollen tubes, such as the elasticity of the cell wall. We used a cellular force microscope (CFM) to measure the apparent stiffness of lily pollen tubes. In combination with a mechanical model based on the finite element method (FEM), this allowed us to calculate turgor pressure and cell wall elasticity, which we found to be around 0.3 MPa and 20-90 MPa, respectively. Furthermore, and in contrast to previous reports, we showed that the difference in stiffness between the pollen tube tip and the shank can be explained solely by the geometry of the pollen tube. CFM, in combination with an FEM-based model, provides a powerful method to evaluate important mechanical parameters of single, growing cells. Our findings indicate that the cell wall of growing pollen tubes has mechanical properties similar to rubber. This suggests that a fully turgid pollen tube is a relatively stiff, yet flexible cell that can react very quickly to obstacles or attractants by adjusting the direction of growth on its way through the female transmitting tissue. PMID:23106269

Vogler, Hannes; Draeger, Christian; Weber, Alain; Felekis, Dimitris; Eichenberger, Christof; Routier-Kierzkowska, Anne-Lise; Boisson-Dernier, Aurélien; Ringli, Christoph; Nelson, Bradley J; Smith, Richard S; Grossniklaus, Ueli

2013-02-01

129

Acute zonal occult outer retinopathy.  

PubMed

Acute zonal occult outer retinopathy (AZOOR) is a rare unilateral or bilateral disease of unknown etiology characterized by focal degeneration of photoreceptors. A total of 131 cases of AZOOR (205 eyes), including the variant known as acute annular outer retinopathy, have been reported in the English language literature. In this group of predominantly white individuals, average age at presentation was 36.7 years, and the male:female ratio was 1:3.2. The majority of patients complained of the acute onset of a scotoma, which was associated with photopsia. Visual acuity was 20/40 or better in 74% of tested eyes, and fundus examination was unremarkable in 76% of eyes. Blind spot enlargement, with or without other field defects, was observed in 75% of the visual fields examined, and electroretinographic abnormalities were recorded in 99% of patients tested. Typically patients retained good visual acuity, although retinal pigment epithelial disturbances commonly developed over time. It was unusual for visual field loss to continue beyond six months. Various treatments have been attempted in patients with AZOOR--including systemic corticosteroids, other systemic immunosuppressive agents, and different antimicrobials--but none have been proven effective. PMID:21056448

Monson, Dinelli M; Smith, Justine R

2011-01-01

130

Fluctuating shells under pressure  

PubMed Central

Thermal fluctuations strongly modify the large length-scale elastic behavior of cross-linked membranes, giving rise to scale-dependent elastic moduli. Whereas thermal effects in flat membranes are well understood, many natural and artificial microstructures are modeled as thin elastic shells. Shells are distinguished from flat membranes by their nonzero curvature, which provides a size-dependent coupling between the in-plane stretching modes and the out-of-plane undulations. In addition, a shell can support a pressure difference between its interior and its exterior. Little is known about the effect of thermal fluctuations on the elastic properties of shells. Here, we study the statistical mechanics of shape fluctuations in a pressurized spherical shell, using perturbation theory and Monte Carlo computer simulations, explicitly including the effects of curvature and an inward pressure. We predict novel properties of fluctuating thin shells under point indentations and pressure-induced deformations. The contribution due to thermal fluctuations increases with increasing ratio of shell radius to thickness and dominates the response when the product of this ratio and the thermal energy becomes large compared with the bending rigidity of the shell. Thermal effects are enhanced when a large uniform inward pressure acts on the shell and diverge as this pressure approaches the classical buckling transition of the shell. Our results are relevant for the elasticity and osmotic collapse of microcapsules. PMID:23150558

Paulose, Jayson; Vliegenthart, Gerard A.; Gompper, Gerhard; Nelson, David R.

2012-01-01

131

Elastic shells with high-contrast material properties as acoustic metamaterial components  

NASA Astrophysics Data System (ADS)

We analyze the acoustic multiple-scattering properties of fluid-filled, elastic cylindrical shells with highly contrasting material properties, and we find for a water background that air-filled shells homogenize into high-bulk modulus, low-density effective fluids. With the exception of a few local resonances spanning very narrow band windows, we find that for common elastic materials the shells are indistinguishable from their effective fluid counterparts for wavelengths larger than the shell's outer diameter. Furthermore, we find that when the elastic shell is composed of a material with impedance larger than water, there will be a specific shell thickness for which the effective fluid properties become impedance-matched. Finally, we demonstrate that the shells can be used as constituent components in regular lattices to create homogenized acoustic metamaterial devices.

Martin, Theodore P.; Layman, Christopher N.; Moore, Kimberly M.; Orris, Gregory J.

2012-04-01

132

Claw morphology, prey size selection and foraging efficiency in generalist and specialist shell-breaking crabs  

Microsoft Academic Search

Claw morphology, and claw-closing forces of four species of intertidal crabs from San Juan Island, Washington were compared and related these findings were related to prey size selection, shell breaking times and total handling times on their snail prey, Littorina sitkana Philippi. Two functional groups of crabs emerged: generalists and specialists on hard-shelled prey. The generalist, Hemigrapsus nudus (Dana), has

Sylvia Behrens Yamada; Elizabeth G. Boulding

1998-01-01

133

Non-uniform thickness in Europa's icy shell: implications for astrobiology mission design  

NASA Astrophysics Data System (ADS)

The exploration of Europa's subsurface ocean is hardly constrained by the presence of an outer ice shell of unknown thickness: a somewhat thin crust would allow easier access to the ocean below. Current estimates for the thickness of Europa's icy surface range from a few km [1] to a few tens of km [2], the shell overlying a liquid water ocean up to 150 km thick [3,4,5]. The surface is believed to be young (mean age of 30-80 Myr [6]) and geologically active [7,8,9], as it is sparsely cratered. Here we report geological evidence indicating that the thickness of Europa's ice crust is actually a complex combination of thicker and thinner areas, highlighting the implications of such structure in the future exploration of the inner ocean. Detailed geologic mapping of impact craters, palimpsests and chaotic terrains distribution on Europa's surface, offers an initial approach to a comprehensive description of the thickness variation in the ice shell. Our analysis is based in: (1) Crater distribution, morphology, diameter and depth. Seminal work by Schenk [2] of transitions in crater shape/diameter suggested enhanced structural collapse of craters with diameter >27-33 km, that will consequently form multiring basins, due to weaker ice or a global ocean at depths >19-25 km. This being true, strictly can only be interpreted regionally: multiring basins indicate regions where the ice shell is thick; in those regions where the icy surface is thin, a bolide impact will breach the ice and leave neither crater nor multiring basin behind, but probably Ganymede's type palimpsests. (2) Palimpsest-type features distribution, indicating regions where the ice shell is too thin to support crater formation after big bolide impacts. In Ganymede, palimpsests are circular, low albedo and relief features formerly formed by impacts [10,11]. (3) Chaotic terrain distribution, considering features tens to hundreds of km across, that may be the evidence for very thin ice areas (from ˜ 2 km to zero shell thickness [12]) with liquid water at shallow depths [5], allowing for bolide penetration, diapirism and the extrusion of water to the surface. The heterogeneity in shell's thickness may be originated in spatial variations in tidal heating [13] and/or warm water upwellings from the silicate interior capable of melt-through the ice from below [12,14]. This thickness heterogeneity can be embedded in a general equatorward thickening trending, due to tidal dissipation and surface temperature variations [15]. A major constraint must be addressed at this point: the dynamism of ductile ice near the base of the shell may drive to decay in lateral thickness contrasts. But this effect has been examined both assuming ice as a Newtonian [16,17,18] and a non-Newtonian material [19], broadly reaching to similar conclusions: global shell thickness variations may survive for up to 100 Myr. In addition, lateral pressure gradients may not decay if they comprise only shallow depths [19]. Therefore, our results point to a dynamic non-uniform Europa's icy shell, displaying some regional and temporal heterogeneity in thickness. As thin/thick ice distribution is as time dependent as the surface ice features are (both are reshaped in periods ˜ 100 Myr), the analysis performed here offers an estimation of the current thickness distribution in the ice shell, estimation that cannot be extrapolated to ancient (e.g., >100 Myr) times. The astrobiological potential the shell and ocean below possess is highlighted by these results: a somewhere thin outer crust allows the possibility for some exogenous materials delivered by asteroids and comets to reach the inner liquid water ocean by breaching the brittle lithosphere [20], and so join to those generated in the interior of Europa via volcanic and hydrothermal activity [21]. In addition, pressure gradients driving the ductile ice at the base of the shell to flow laterally may help to redistribute such materials among the inner ice shell and/or ocean through time. Our results have a direct deal with the investigation of Eur

Fairén, A.; Amils, R.

134

Chandra Peers Into Outer Space  

NSDL National Science Digital Library

NASA's newest space telescope, the Chandra X-ray Observatory, was launched into orbit only two months ago. Named for the late Indian-American Nobel laureate, Subrahmanyan Chandrasekhar, the Chandra Observatory is already providing scientists with the first "X-ray images and spectra of violent, high-temperature events and objects." In addition to their sheer mystique, these color images increase scientists's understanding of the structure and evolution of the universe. Managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, the Chandra X-Ray Observatory also serves as a unique tool for studying detailed physics "in a unique laboratory -- the universe itself." This week's In The News highlights the Chandra X-Ray Observatory; the nine sites listed offer background information, commentary, and recent images from outer space.

Payne, Laura X.

135

Acute zonal occult outer retinopathy.  

PubMed

Retinal photoreceptor dysfunction is an uncommon and often unrecognized cause of acute visual loss. Acute zonal occult outer retinopathy (AZOOR) has been reported to cause cone and rod dysfunction. Patients with AZOOR may present with normal visual acuity, normal fluorescein angiography, and a normal fundus examination despite severe loss of visual field. A healthy young white female presented with acute, unilateral loss of visual field and an afferent pupillary defect, but normal visual acuity, color vision, fundus examination, and fluorescein angiogram. A pattern visual evoked potential was normal, but an electroretinogram showed a unilateral peripheral photoreceptor dysfunction consistent with the diagnosis of AZOOR. Ophthalmologists should be aware of the diagnosis of AZOOR and should consider an ERG in the evaluation of any patient with unexplained visual field loss even in the presence of normal visual acuity, color vision, fluorescein angiography, or retinal examination. PMID:8689493

Lee, A G; Prager, T C

1996-02-01

136

How Hard is Chocolate?  

NSDL National Science Digital Library

Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth don’t break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

2007-12-20

137

Ordering of hard particles between hard walls  

NASA Astrophysics Data System (ADS)

The structure of a fluid of hard Gaussian overlap particles of elongation ? = 5, confined between two hard walls, has been calculated from density-functional theory and Monte Carlo simulations. By using the exact expression for the excluded volume kernel (Velasco E and Mederos L 1998 J. Chem. Phys. 109 2361) and solving the appropriate Euler-Lagrange equation entirely numerically, we have been able to extend our theoretical predictions into the nematic phase, which had up till now remained relatively unexplored due to the high computational cost. Simulation reveals a rich adsorption behaviour with increasing bulk density, which is described semi-quantitatively by the theory without any adjustable parameters.

Chrzanowska, A.; Teixeira, P. I. C.; Ehrentraut, H.; Cleaver, D. J.

2001-05-01

138

Discovery Collection: Oyster Shells  

NSDL National Science Digital Library

Oyster Shells is one of the AMNH Education Department's many collections of specimens and artifacts gathered the world over by explorers and scientists. In its online Discovery Collection form, Oyster Shells includes photographs of 15 specimens with classification and distribution details, an interactive key that guides you through specimen identification, an activity where students select and identify a specimen photograph using the interactive identification key and an Educator's Guide with suggestions for how to use the Oyster Shells Discovery Collection in the classroom.

Lisa Breslof

139

Off-Shell Tachyons  

E-print Network

The idea that the new particles invented in some models beyond the standard model can appear only inside the loops is attractive. In this paper, we fill these loops with off-shell tachyons, leading to a solution of the zero results of the loop diagrams involving the off-shell non-tachyonic particles. We also calculate the Passarino-Veltman $A_0^o$ and $B_0^o$ of the off-shell tachyons.

Yi-Lei Tang

2015-01-30

140

Off-Shell Tachyons  

E-print Network

The idea that the new particles invented in some models beyond the standard model can appear only inside the loops is attractive. In this paper, we fill these loops with off-shell tachyons, leading to a solution of the zero results of the loop diagrams involving the off-shell non-tachyonic particles. We also calculate the Passarino-Veltman $A_0^o$ and $B_0^o$ of the off-shell tachyons.

Tang, Yi-Lei

2015-01-01

141

Outer trapped surfaces are dense near MOTSs  

NASA Astrophysics Data System (ADS)

We show that any vacuum initial data set containing a marginally outer trapped surface S and satisfying a ‘no KIDs’ condition can be perturbed near S so that S becomes strictly outer trapped in the new vacuum initial data set. This, together with the results in Eichmair et al (2012), gives a precise sense in which generic initial data containing marginally outer trapped surfaces lead to geodesically incomplete spacetimes.

Chru?ciel, Piotr T.; Galloway, Gregory J.

2014-02-01

142

Session: Hard Rock Penetration  

SciTech Connect

This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

1992-01-01

143

Hardness Tester for Polyur  

NASA Technical Reports Server (NTRS)

Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

Hauser, D. L.; Buras, D. F.; Corbin, J. M.

1987-01-01

144

Hard diffraction in CDF  

SciTech Connect

We present Run I results on hard diffraction obtained by the CDF Collaboration in proton-antiproton collisions at the Fermilab Tevatron. They are compared with results from the DESY ep collider HERA and/or theoretical predictions to test factorization in hard diffraction. In addition, the CDF program for diffractive studies in Run II is presented briefly.

K. Terashi

2002-07-12

145

The hard metal diseases  

SciTech Connect

Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure.66 references.

Cugell, D.W. (Department of Medicine, Northwestern University Medical School, Chicago, IL (United States))

1992-06-01

146

Microstructures and mechanical behavior of mollusk shells  

SciTech Connect

Biological hard tissues are load-bearing structural materials, composed of a mineral (ceramic) component and an organic (protein) component. The microstructures of three composite designs commonly found in mollusk shells, the nacreous, foliated, and crossed-lamellar structures are discussed. Although all of these can be viewed as laminar composites, differences exist in the morphology, crystal structure, defect microstructure, and spatial organization of the mineral, CaCo{sub 3}. Electron microscopy investigations of these materials reveal a variety of crystallographic defects, the details of which have been used to refine existing models for biomineralization in these tissues. Flexural strengths in four-point bending are on the order of 100 Mpa. Examples of graceful failure'', i.e. stable crack growth in bulk samples, in the crossed-lamellar and foliated structures are reported. Fractography of such specimens reveals that a number of familiar toughening mechanisms operate together to produce this desirable structural flaw tolerance. Even more unusual is the fact that mollusk shells are harder than the native minerals from which they are made The damage zones and the anisotropy of hardness suggest an explanation for the anomalous hardness based on microstructural design rather than on intrinsic hardening of the mineral phase. 27 refs., 15 figs., 2 tabs.

Laraia, V.J.; Heuer, A.H. (Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Materials Science and Engineering)

1991-03-01

147

Sensational spherical shells  

Microsoft Academic Search

Fluid-dynamic and capillary forces can be used to form nearly perfect, very small spherical shells when a liquid that can solidify is passed through an annular die to form an annular jet. Gravity and certain properties of even the most ideal materials, however, can cause slight asymmetries. The primary objective of the present work is the control of this shell

M. C. Lee; J. M. Kendall Jr.; P. A. Bahrami; T. G. Wang

1986-01-01

148

SHELL METHOD DEMO GALLERY  

NSDL National Science Digital Library

This is a gallery of animations that can be used to illustrate the shell method for computing volumes of solids of revolution. The animations are designed to be used by the instructor in a classroom setting or by students as they acquire a visual background relating to solids of revolution and the steps of the shell method.

Roberts, Lila F.

2002-02-02

149

I Learned about Shells!  

NSDL National Science Digital Library

Through the use of nonfiction text, students will be able to share their prior knowledge and schema of shells. Students will practice gathering information from a text, help create a KEL chart through class and small group discussions, and will use the information learned to create an informative writing about shell animals.

Kris Ryan

2012-06-26

150

76 FR 54787 - Outer Continental Shelf Official Protraction Diagram, Lease Maps, and Supplemental Official Outer...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Shelf Official Protraction Diagram, Lease Maps, and Supplemental Official Outer Continental...Shelf Official Protraction Diagram, Lease Maps, and Supplemental Official Outer Continental...Official Protraction Diagram (OPD), Lease Maps, and Supplemental Official OCS Block...

2011-09-02

151

Cohesive Elements for Shells  

NASA Technical Reports Server (NTRS)

A cohesive element for shell analysis is presented. The element can be used to simulate the initiation and growth of delaminations between stacked, non-coincident layers of shell elements. The procedure to construct the element accounts for the thickness offset by applying the kinematic relations of shell deformation to transform the stiffness and internal force of a zero-thickness cohesive element such that interfacial continuity between the layers is enforced. The procedure is demonstrated by simulating the response and failure of the Mixed Mode Bending test and a skin-stiffener debond specimen. In addition, it is shown that stacks of shell elements can be used to create effective models to predict the inplane and delamination failure modes of thick components. The results indicate that simple shell models can retain many of the necessary predictive attributes of much more complex 3D models while providing the computational efficiency that is necessary for design.

Davila, Carlos G.; Camanho, Pedro P.; Turon, Albert

2007-01-01

152

Assessment of the mechanism of elemental incorporation into bivalve shells (Arctica islandica) based on elemental distribution at the microstructural scale  

NASA Astrophysics Data System (ADS)

To address the mechanism of elemental incorporation into shells of the bivalve Arctica islandica, we performed two-dimensional elemental mapping of Sr, Mg, and S at a ˜3 ?m spatial resolution using electron microprobe. These elemental distributions were precisely compared to the shell microstructure. The Sr distribution was intimately linked to the S concentration and/or shell microstructure. Sr showed a clear annual pattern with higher values at the annual growth lines and lower values in annual growth increments. The Sr and S concentrations were higher near sub-annual growth lines than in the adjacent regions, which were dominated by acicular microstructure (middle shell layer) or homogeneous microstructure (outer shell layer). Furthermore, the Sr concentration was lower in the middle shell layer than in the outer shell layer, but there was no clear difference in the S concentration between the two layers. The observed elemental distribution in the shell can be reasonably explained by the hypothesis that the organic composition at the calcification site, i.e. in the extrapallial space, can facilitate the preferential elemental incorporation into calcium carbonate. The Sr/Ca ratio shows micrometer scale variation within the shell, suggesting that fine spatial resolution, comparable to the shell microstructure, is required for the analysis of elemental distribution to avoid time-averaging and to correctly evaluate the magnitude of the compositional variation in the shell for past environmental reconstruction.

Shirai, Kotaro; Schöne, Bernd R.; Miyaji, Tsuzumi; Radarmacher, Pascal; Krause, Richard A.; Tanabe, Kazushige

2014-02-01

153

PLANETARY ATMOSPHERES Jupiter and the Outer Planets  

E-print Network

PLANETARY ATMOSPHERES Contents Jupiter and the Outer Planets Mars Venus Jupiter and the Outer range of atmospheres. The giant planets F Jupiter, Saturn, Uranus, and Neptune F are fluid objects whose equilibrium with solid nitrogen ice on their surfaces. And the Galilean satellites of Jupiter F Io, Europa

154

Liquid sodium model of Earth's outer core  

Microsoft Academic Search

Convective motions in Earth's outer core are responsible for the generation of the geomagnetic field. We present liquid sodium convection experiments in a spherical vessel, designed to model the convective state of Earth's outer core. Heat transfer, zonal fluid velocities, and properties of temperature fluctuations were measured for different rotation rates O and temperature drops DeltaT across the convecting sodium.

Woodrow Shew

2004-01-01

155

UNITED NATIONS OFFICE FOR OUTER SPACE AFFAIRS  

E-print Network

GPSoperationalcontrolsegmentconsistsoffourmajorsubsystems:amastercontrol station, an alternate master control station, a network of four ground antennas and a network of globallyUNITED NATIONS OFFICE FOR OUTER SPACE AFFAIRS Current and Planned Global and Regional Navigation Satellite Systems Provider's Forum UNITED NATIONS #12;#12;UNITED NATIONS OFFICE FOR OUTER SPACE AFFAIRS

Schrijver, Karel

156

Effect of milling time and CNT concentration on hardness of CNT/Al{sub 2024} composites produced by mechanical alloying  

SciTech Connect

Carbon nanotube/2024 aluminum alloy (CNT/Al{sub 2024}) composites were fabricated with a combination of mechanical alloying (MA) and powder metallurgy routes. Composites were microstructurally and mechanically evaluated at sintering condition. A homogeneous dispersion of CNTs in the Al matrix was observed by a field emission scanning electron microscopy. High-resolution transmission electron microscopy confirmed not only the presence of well dispersed CNTs but also needle-like shape aluminum carbide (Al{sub 4}C{sub 3}) crystals in the Al matrix. The formation of Al{sub 4}C{sub 3} was suggested as the interaction between the outer shells of CNTs and the Al matrix during MA process in which crystallization took place after the sintering process. The mechanical behavior of composites was evaluated by Vickers microhardness measurements indicating a significant improvement in hardness as function of the CNT content. This improvement was associated to a homogeneous dispersion of CNTs and the presence of Al{sub 4}C{sub 3} in the aluminum alloy matrix. - Highlights: Black-Right-Pointing-Pointer The 2024 aluminum alloy was reinforced by CNTs by mechanical alloying process. Black-Right-Pointing-Pointer Composites were microstructural and mechanically evaluated after sintering condition. Black-Right-Pointing-Pointer The greater the CNT concentration, the greater the hardness of the composites. Black-Right-Pointing-Pointer Higher hardness in composites is achieved at 20 h of milling. Black-Right-Pointing-Pointer The formation of Al{sub 4}C{sub 3} does not present a direct relationship with the milling time.

Perez-Bustamante, R. [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No.120, C.P. 31109, Chihuahua, Chih. (Mexico)] [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No.120, C.P. 31109, Chihuahua, Chih. (Mexico); Perez-Bustamante, F. [Universidad Autonoma de Chihuahua (UACH), Facultad de Ingenieria, Circuito No. 1 Nuevo Campus Universitario, C.P. 31125, Chihuahua, Chih. (Mexico)] [Universidad Autonoma de Chihuahua (UACH), Facultad de Ingenieria, Circuito No. 1 Nuevo Campus Universitario, C.P. 31125, Chihuahua, Chih. (Mexico); Estrada-Guel, I. [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No.120, C.P. 31109, Chihuahua, Chih. (Mexico)] [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No.120, C.P. 31109, Chihuahua, Chih. (Mexico); Licea-Jimenez, L. [Centro de Investigacion en Materiales Avanzados S.C. (CIMAV), Unidad Mty, Autopista Monterrey-Aeropuerto Km 10, A. P. 43, C.P. 66600, Apodaca, N.L. (Mexico)] [Centro de Investigacion en Materiales Avanzados S.C. (CIMAV), Unidad Mty, Autopista Monterrey-Aeropuerto Km 10, A. P. 43, C.P. 66600, Apodaca, N.L. (Mexico); Miki-Yoshida, M. [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No.120, C.P. 31109, Chihuahua, Chih. (Mexico)] [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No.120, C.P. 31109, Chihuahua, Chih. (Mexico); Martinez-Sanchez, R., E-mail: roberto.martiez@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No.120, C.P. 31109, Chihuahua, Chih. (Mexico)

2013-01-15

157

Low-Frequency Waves in the Outer Heliosphere  

NASA Astrophysics Data System (ADS)

The outer heliosphere beyond some 10 AU is dominated by mass by interstellar neutral Hydrogen (H). Neutral H is coupled to the background solar wind plasma by charge exchange processes, which leads to the creation of a suprathermal pickup ion (PUI) population. The initially unstable ring beam PUI distribution is isotropized to form a filled shell distribution. The PUI contribution to the thermal solar wind pressure/temperature is sizable and in fact can dominate that of the colder thermal solar wind protons. Furthermore, the PUI distribution does not equilibrate or thermalize with the background solar wind plasma, and should therefore be regarded as a distinct distribution. Based on an elaboration of a three-fluid model, we investigate the effect of PUIs on the low-frequency wave properties of the outer heliosphere. To maintain tractability initially, we neglect the electron mass and obtain a 10th-order dispersion relation (compared to the 6th-order two-fluid dispersion relation). Our analysis reveals the existence of several wave modes that do not have a standard solar wind two-fluid plasma counterpart. For the zero angle case, of the 10 solutions, it is possible to obtain 6 analytic solutions for a general value of the ratio of electron number density to the thermal proton number density, four of which are dispersive Alfven waves (left and right polarized, two forward and two backward). Two other solutions are finite frequency modes, and the remaining four modes are magnetoacoustic modes (2 forward, 2 backward). One solution is a (magneto)acoustic wave with the usual 2-fluid sound speed, and the second is a (magneto)acoustic mode with a sound speed associated with the PUI distribution. Both (magneto)acoustic modes couple to the 'other fluids.' We present an analysis of the full dispersion relation for wave modes in the outer heliosphere, clarifying the role of PUIs in determining the properties of low-frequency fluctuations.

Zank, G. P.; Hunana, P.; Goldstein, M. L.

2013-12-01

158

Diffusion and injections in the radiation belts: L shell coupling  

NASA Astrophysics Data System (ADS)

The outer zone of the electron radiation belts is divided in three main regions in L shell: the P0 region (L=3-4 approx.), the P1 region (L=4-7) or heart of the outer zone, and the P2 region (L>7) which is related to the cusp and plasma sheet [Vassiliadis et al., JGR 2002; Phys. Plasmas, 2003]. We measure the correlation between fluxes at adjacent and nearby L shells. We use autoregressive models to account for the coupling. The correlation values and the model coefficients are interpreted in terms of slow diffusion (time scales >=2 days) and rapid injections (<1 day). We parametrize the response by the electron energy measured by SAMPEX/PET fluxes at 2-6 MeV and EXOS-C/HEP at 0.19-3.5 MeV.

Vassiliadis, D.; Weigel, R. S.; Klimas, A. J.; Baker, D. N.; Kanekal, S. G.

2002-12-01

159

Hard sphere mixtures near a hard wall  

Microsoft Academic Search

Hard spheres with ratios of diameters of 3:5 and 1:3 and at various densities are studied by means of grand canonical ensemble (GCE) simulations, first- and second-order Percus—Yevick theory, scaled particle theory (SPT) and density functional theory (DFT). Generally, but not always, the density profiles of the first-order Percus—Yevick (PY1) theory results are smaller at contact than the GCE simulation

JERZY P. NOWORYTA; DOUGLAS HENDERSON; STEFAN SOKO?OWSKI; KWONG-YU CHAN

1998-01-01

160

Production of Polymer Core-Shell Colloids with High Uniformity via Coaxial Electrospray  

NASA Astrophysics Data System (ADS)

Although nanofibers fabricated by electrospinning have been attracting wide interest, the production of colloids by electrospraying has not much studied so far. We have developed a simple method for the production of core-shell colloids with high uniformity by means of the coaxial electrospray. Contrary to usual coaxial setup, the inner nozzle was set to touch the inside wall of the outer nozzle for reproducible production. A polymer solution for the core was introduced through the outer nozzle and another solution for the shell was provided through the inner nozzle. The structure of the colloids was dependent on the polymer concentration, relative feed ratio between the polymer solutions. Especially, core-shell structured colloids are our primary interest due to their promising uses in drug-delivery systems, cosmetics, and food industries. This talk will present the production of core-shell colloids consisting of two polymer components.

Hwang, Yoon Kyun; Jeong, Unyong

2008-03-01

161

Spin and hard processes  

E-print Network

It is argued that spin is a fundamental aspect of gauge theories at short distances. As a consequence there are characteristic helicity asymmetries in hard inclusive and exclusive reactions of which a few are discussed.

P. Kroll

2002-10-16

162

Failure of Viral Shells  

NASA Astrophysics Data System (ADS)

We report a combined theoretical and experimental study of the structural failure of viral shells under mechanical stress. We find that discontinuities in the force-indentation curve associated with failure should appear when the so-called Föppl von Kármán (FvK) number exceeds a critical value. A nanoindentation study of a viral shell subject to a soft-mode instability, where the stiffness of the shell decreases with increasing pH, confirms the predicted onset of failure as a function of the FvK number.

Klug, William S.; Bruinsma, Robijn F.; Michel, Jean-Philippe; Knobler, Charles M.; Ivanovska, Irena L.; Schmidt, Christoph F.; Wuite, Gijs J. L.

2006-12-01

163

Biomechanics of Turtle Shells: How Whole Shells Fail in  

E-print Network

Biomechanics of Turtle Shells: How Whole Shells Fail in Compression PAUL M. MAGWENE1 AND JOHN J of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois The turtle shell serves an obvious and tactile perception (Rosenberg, '86). The turtle shell is thus a multifunctional system

Socha, Jake

164

Replicated Nickel Optics for the Hard-X-Ray Region  

NASA Technical Reports Server (NTRS)

Replicated nickel optics has been used extensively in x-ray astronomy, most notable for the XMM/Newton mission. Thc combination of relative ease of fabrication and the inherent stability of full shell optics, make them FIJI attractive approach for medium-resolution, high-throughput applications. MSFC has been developing these optics for use in the hard-x-ray region. Efforts at improving the resolution of these, particularly the very-thin shells required to meet thc weight budget of future missions, will be described together with the prospects for significant improvements down to the 5-arcsec level.

Ramsey, Brian

2005-01-01

165

Incorporation of squalene into rod outer segments  

SciTech Connect

We have reported previously that squalene is the major radiolabeled nonsaponifiable lipid product derived from ({sup 3}H)acetate in short term incubations of frog retinas. In the present study, we demonstrate that newly synthesized squalene is incorporated into rod outer segments under similar in vitro conditions. We show further that squalene is an endogenous constituent of frog rod outer segment membranes; its concentration is approximately 9.5 nmol/mumol of phospholipid or about 9% of the level of cholesterol. Pulse-chase experiments with radiolabeled precursors revealed no metabolism of outer segment squalene to sterols in up to 20 h of chase. Taken together with our previous absolute rate studies, these results suggest that most, if not all, of the squalene synthesized by the frog retina is transported to rod outer segments. Synthesis of protein is not required for squalene transport since puromycin had no effect on squalene incorporation into outer segments. Conversely, inhibition of isoprenoid synthesis with mevinolin had no effect on the incorporation of opsin into the outer segment. These latter results support the conclusion that the de novo synthesis and subsequent intracellular trafficking of opsin and isoprenoid lipids destined for the outer segment occur via independent mechanisms.

Keller, R.K.; Fliesler, S.J. (Univ. of South Florida College of Medicine, Tampa (USA))

1990-08-15

166

Outer planets and icy satellites  

NASA Technical Reports Server (NTRS)

The resources offered by the outer bodies in the Solar System, starting with the main belt asteroids and Jovian System, are not only larger and more diverse but may even be easier to reach than, say, those of Mars. The use of their material, including water and organic matter, depends exclusively on the general strategy of exploration of the Solar System. Of major interest in this respect are the large ice satellites - Titan, Ganymede, and Callisto. Motion through the planetary magnetospheres excites in their ice envelopes megampere currents which, in the presence of rocky, etc., inclusions with electronic conduction should lead to the bulk electrolysis of ice and accumulation in it of 2H2 + O2 in the form of a solid solution. With the concentration of 2H2 + O2 reaching about 15 wt. percent, the solution becomes capable of detonation by a strong meteoritic impact. An explosion of Ganymede's ice envelope about 0.5 By ago could account for the formation of the Trojans and irregular satellites, all known differences between Ganymede and Callisto, and many other things. The explosion of a small icy planet with M approx less than 0.5 Moon created the asteroid belt. Two to three explosions occurred on Io, and two on Europa. The specific features of the longperiod comets close to Saturn's orbit permit dating Titan's envelope explosion as 10,000 yr ago, which produced its thick atmosphere, young Saturn's rings, as well as a reservoir of ice fragments saturated by 2H2 + O2, i.e., cometary nuclei between the orbits of Jupiter and Saturn. Thus these nuclei should contain, besides organic matter, also 2H2 + O2, which could be used for their transportation as well as for fuel for spaceships. Ices of such composition can reside deep inside Deimos, the Trojans, C-asteroids, etc. The danger of a future explosion of Callisto's electrolyzed ices, which would result in a catastrophic bombardment of the Earth by comets, may be high enough to warrant a revision of the priorities and strategy of space exploration.

Drobyshevski, E. M.

1991-01-01

167

RESISTANCE OF THE SHELL MEMBRANE AND MINERAL LAYER TO DIFFUSION OF OXYGEN AND WATER IN FLEXIBLE-SHELLED EGGS OF THE SNAPPING TURTLE (CHELYDRA SERPENTINA)  

Microsoft Academic Search

At oviposition, flexible eggshells of many turtles have an outer mineral layer and an inner membrane layer of approximately equal thickness. We measured conductances of both layers to H20 and 02 at various levels of eggshell hydration. Both the mineral layer of the eggshell and the shell membrane offer significant resistance to diffusion of water vapor and oxygen in eggshells

MARTIN E. FEDER; SALLY L. SATEL; ALLEN G. GIBBS

168

C-Shell Cookbook  

NASA Astrophysics Data System (ADS)

This cookbook describes the fundamentals of writing scripts using the UNIX C shell. It shows how to combine Starlink and private applications with shell commands and constructs to create powerful and time-saving tools for performing repetitive jobs, creating data-processing pipelines, and encapsulating useful recipes. The cookbook aims to give practical and reassuring examples to at least get you started without having to consult a UNIX manual. However, it does not offer a comprehensive description of C-shell syntax to prevent you from being overwhelmed or intimidated. The topics covered are: how to run a script, defining shell variables, prompting, arithmetic and string processing, passing information between Starlink applications, obtaining dataset attributes and FITS header information, processing multiple files and filename modification, command-line arguments and options, and loops. There is also a glossary.

Currie, Malcolm J.

169

Scripts Shell Laurent Tichit  

E-print Network

variable IFS. On peut la modifier. Laurent Tichit () Scripts Shell 6 avril 2011 10 / 47 #12;Lister les variables lister toutes les variables : set lister toutes les variables d'environnement (celles qui sont

Tichit, Laurent

170

Hollow spherical shell manufacture  

DOEpatents

A process for making a hollow spherical shell of silicate glass composition in which an aqueous suspension of silicate glass particles and an immiscible liquid blowing agent is placed within the hollow spherical cavity of a porous mold. The mold is spun to reduce effective gravity to zero and to center the blowing agent, while being heated so as to vaporize the immiscible liquid and urge the water carrier of the aqueous suspension to migrate into the body of the mold, leaving a green shell compact deposited around the mold cavity. The green shell compact is then removed from the cavity, and is sintered for a time and a temperature sufficient to form a silicate glass shell of substantially homogeneous composition and uniform geometry.

O'Holleran, Thomas P. (Belleville, MI)

1991-01-01

171

Hollow spherical shell manufacture  

DOEpatents

A process is disclosed for making a hollow spherical shell of silicate glass composition in which an aqueous suspension of silicate glass particles and an immiscible liquid blowing agent is placed within the hollow spherical cavity of a porous mold. The mold is spun to reduce effective gravity to zero and to center the blowing agent, while being heated so as to vaporize the immiscible liquid and urge the water carrier of the aqueous suspension to migrate into the body of the mold, leaving a green shell compact deposited around the mold cavity. The green shell compact is then removed from the cavity, and is sintered for a time and a temperature sufficient to form a silicate glass shell of substantially homogeneous composition and uniform geometry. 3 figures.

O'Holleran, T.P.

1991-11-26

172

Dynamics of a suspension of interacting yolk-shell particles  

E-print Network

In this work we study the self-diffusion properties of a liquid of hollow spherical particles (shells)bearing a smaller solid sphere in their interior (yolks). We model this system using purely repulsive hard-body interactions between all (shell and yolk) particles, but assume the presence of a background ideal solvent such that all the particles execute free Brownian motion between collisions,characterized by short-time self-diffusion coefficients D0s for the shells and D0y for the yolks. Using a softened version of these interparticle potentials we perform Brownian dynamics simulations to determine the mean squared displacement and intermediate scattering function of the yolk-shell complex. These results can be understood in terms of a set of effective Langevin equations for the N interacting shell particles, pre-averaged over the yolks' degrees of freedom, from which an approximate self-consistent description of the simulated self-diffusion properties can be derived. Here we compare the theoretical and simulated results between them, and with the results for the same system in the absence of yolks. We find that the yolks, which have no effect on the shell-shell static structure, influence the dynamic properties in a predictable manner, fully captured by the theory.

L. E. Sánchez Díaz; E. C. Cortes-Morales; X. Li; Wei-Ren Chen; M. Medina-Noyola

2014-06-23

173

Dynamics of a suspension of interacting yolk-shell particles  

NASA Astrophysics Data System (ADS)

In this work we study the self-diffusion properties of a liquid of hollow spherical particles (shells) bearing a smaller solid sphere in their interior (yolks). We model this system using purely repulsive hard-body interactions between all (shell and yolk) particles, but assume the presence of a background ideal solvent such that all the particles execute free Brownian motion between collisions, characterized by short-time self-diffusion coefficients D^0s for the shells and D^0y for the yolks. Using a softened version of these interparticle potentials we perform Brownian dynamics simulations to determine the mean squared displacement and intermediate scattering function of the yolk-shell complex. These results can be understood in terms of a set of effective Langevin equations for the N interacting shell particles, pre-averaged over the yolks' degrees of freedom, from which an approximate self-consistent description of the simulated self-diffusion properties can be derived. Here we compare the theoretical and simulated results between them, and with the results for the same system in the absence of yolks. We find that the yolks, which have no effect on the shell-shell static structure, influence the dynamic properties in a predictable manner, fully captured by the theory.

Sánchez Díaz, L. E.; Cortes-Morales, E. C.; Li, X.; Chen, Wei-Ren; Medina-Noyola, M.

2014-12-01

174

Large scale production of yolk-shell ?-tricalcium phosphate powders, and their bioactivities as novel bone substitutes.  

PubMed

This paper proposes the production of yolk-shell structured ?-tricalcium phosphate (?-TCP) powders using a spray-drying method, suitable for commercial scale production. Spray-dried precursor powders, consisting of calcium-phosphate salts and each of the various carbon source materials, are combusted in an oxygen atmosphere to obtain a yolk-shell structure. Only dextrin among the carbon source materials investigated shows promise in the production of ?-TCP yolk-shell powders. By evaluating their apatite-forming capacity in simulated body fluid, the outstanding bioactivity of ?-TCP yolk-shell powders is confirmed: numerous acicular and newly formed hydroxyl carbonate apatite crystals cover the entire ?-TCP surface after a single day of soaking. These crystals are observed on both the outer and inner surfaces of the shells, and on the outer surface of the core, which is encouraging for its potential use as a bone grafting material. PMID:25005151

Cho, Jung Sang; Lee, Jong-Heun; Kang, Yun Chan

2014-08-28

175

Limits on a radio shell around the Crab Nebula  

NASA Astrophysics Data System (ADS)

A search at radio wavelengths for the hypothetical outer shell of the Crab Nebula is reported, and no shell has been detected. It is indicated that such a shell is fainter than expected for the surface brightness-linear diameter relation for shell type supernova remnants. Alternative explanations for the optical shell include emission from the hypothetical remnant shell, light scattered off dust grains from the surrounding nebula, and the leakage of synchrotron emitting electrons from the nebula. It is also noted that because of the nonspherical shape of the halo, a Stromgren sphere ionized by the nonthermal UV synchrotron radiation of the nebula is implausible. In addition, in order to prove the emission theory, it is suggested that high velocity gas in the halo must be detected through optical spectroscopy. Finally, further X-ray observations may be useful in order to confirm and map a possible soft X-ray halo peripheral to the nebula, but this halo is probably a result of X-ray scattering.

Wilson, A. S.; Weiler, K. W.

1982-11-01

176

Free volume distribution of nearly jammed hard sphere packings  

NASA Astrophysics Data System (ADS)

We calculate the free volume distributions of nearly jammed packings of monodisperse and bidisperse hard sphere configurations. These distributions differ qualitatively from those of the fluid, displaying a power law tail at large free volumes, which constitutes a distinct signature of nearly jammed configurations, persisting for moderate degrees of decompression. We reproduce and explain the observed distribution by considering the pair correlation function within the first coordination shell for jammed hard sphere configurations. We analyze features of the equation of state near jamming, and discuss the significance of observed asphericities of the free volumes to the equation of state.

Maiti, Moumita; Sastry, Srikanth

2014-07-01

177

Free volume distribution of nearly jammed hard sphere packings  

E-print Network

We calculate the free volume distributions of nearly jammed packings of monodisperse and bidisperse hard sphere configurations. These distributions differ qualitatively from those of the fluid, displaying a power law tail at large free volumes, which constitutes a distinct signature of nearly jammed configurations, persisting for moderate degrees of decompression. We reproduce and explain the observed distribution by considering the pair correlation function within the first coordination shell for jammed hard sphere configurations. We analyze features of the equation of state near jamming, and discuss the significance of observed asphericities of the free volumes to the equation of state.

Moumita Maiti; Srikanth Sastry

2014-07-25

178

Free volume distribution of nearly jammed hard sphere packings.  

PubMed

We calculate the free volume distributions of nearly jammed packings of monodisperse and bidisperse hard sphere configurations. These distributions differ qualitatively from those of the fluid, displaying a power law tail at large free volumes, which constitutes a distinct signature of nearly jammed configurations, persisting for moderate degrees of decompression. We reproduce and explain the observed distribution by considering the pair correlation function within the first coordination shell for jammed hard sphere configurations. We analyze features of the equation of state near jamming, and discuss the significance of observed asphericities of the free volumes to the equation of state. PMID:25084929

Maiti, Moumita; Sastry, Srikanth

2014-07-28

179

Outer planet probe engineering model structural tests  

NASA Technical Reports Server (NTRS)

A series of proof of concept structural tests was performed on an engineering model of the Outer Planets Atmospheric Entry Probe. The tests consisted of pyrotechnic shock, dynamic and static loadings. The tests partially verified the structural concept.

Smittkamp, J. A.; Gustin, W. H.; Griffin, M. W.

1977-01-01

180

Caustics for inner and outer billiards  

Microsoft Academic Search

With a plane closed convex curve,T, we associate two area preserving twist maps: the (classical) inner billiard inT and the outer billiard in the exterior ofT. The invariant circles of these twist maps correspond to certain plane curves: the inner and the outer caustics ofT. We investigate how the shape ofT determines the possible location of caustics, establish the existence

Anatole Katok

1995-01-01

181

Planetary Aeronomy of the Outer Solar System  

NASA Astrophysics Data System (ADS)

This talk will give a historical tour of the highlights of my research on atmospheres in the outer solar system and their interaction with the magnetospheric plasma. Topics include atmospheric photochemistry, the Io plasma torus, the Galilean satellites, and the nitrogen atmospheres on Titan, Triton, and Pluto. The important role of observations combined with theory will be emphasized. The talk will finish with current research on the role that atmospheric escape plays on atmospheric structure in the outer solar system.

Strobel, Darrell

2012-10-01

182

Effects of alga polysaccharide capsule shells on in-vivo bioavailability and disintegration  

NASA Astrophysics Data System (ADS)

Gelatin has been used in hard capsule shells for more than a century, and some shortcomings have appeared, such as high moisture content and risk of transmitting diseases of animal origin to people. Based on available studies regarding gelatin and vegetable shells, we developed a new type of algal polysaccharide capsule (APPC) shells. To test whether our products can replace commercial gelatin shells, we measured in-vivo plasma concentration of 12 selected volunteers with a model drug, ibuprofen, using high performance liquid chromatography (HPLC), by calculating the relative bioavailability of APPC and Qualicaps® referenced to gelatin capsules and assessing bioequivalence of the three types of shells, and calculated pharmacokinetic parameters with the software DAS 2.0 (China). The results show that APPC shells possess bioequivalence with Qualicaps® and gelatin shells. Moreover, the disintegration behavior of four types of shells (APPC, Vegcaps®, Qualicaps® and gelatin shells) with the content of lactose and radioactive element (99mTc) was observed via gamma-scintigraphic images. The bioavailability and gamma-scintigraphic studies showed that APPC was not statistically different from other vegetable and gelatin capsule shells with respect to in-vivo behavior. Hence, it can be concluded that APPCs are exchangeable with other vegetable and gelatin shells.

Li, Ting; Guo, Shuju; Ma, Lin; Yuan, Yi; Han, Lijun

2012-01-01

183

The Impact of Ceramic Shell Strength on Hot Tearing during Investment Casting  

SciTech Connect

The effect of ceramic shell strength on hot tearing susceptibility during solidification was inspected practicing investment casting of the cobalt-base superalloy samples with the same casting conditions, but different ceramic shell systems. Results showed that the lower the ceramic shell strength upon using polymer additives, the lower the hindered contraction rate, and the lower the hindered contraction rate, the smaller the hot tearing tendency. Optical microscopy and electron microscopy scanning revealed that the hot tear propagated along the last solidified interdendritic phase, and that the hot tear surface had two major modes: (1) the ductile region in the outer layer; and (2) the inner region of liquid embrittlement.

Norouzi, Saeid [MAPNA GROUP Co (Iran, Islamic Republic of); Farhangi, Hassan [School of Metallurgy and Materials Engineering, University of Tehran (Iran, Islamic Republic of)

2011-01-17

184

Outer Hair Cell Electromotility and Otoacoustic Emissions*  

PubMed Central

Outer hair cell electromotility is a rapid, force generating, length change in response to electrical stimulation. DC electrical pulses either elongate or shorten the cell and sinusoidal electrical stimulation results in mechanical oscillations at acoustic frequencies. The mechanism underlying outer hair cell electromotility is thought to be the origin of spontaneous otoacoustic emissions. The ability of the cell to change its length requires that it be mechanically flexible. At the same time the structural integrity of the organ of Corti requires that the cell possess considerable compressive rigidity along its major axis. Evolution appears to have arrived at novel solutions to the mechanical requirements imposed on the outer hair cell. Segregation of cytoskeletal elements in specific intracellular domains facilitates the rapid movements. Compressive strength is provided by a unique hydraulic skeleton in which a positive hydrostatic pressure in the cytoplasm stabilizes a flexible elastic cortex with circumferential tensile strength. Cell turgor is required in order that the pressure gradients associated with the electromotile response can be communicated to the ends of the cell. A loss in turgor leads to loss of outer hair cell electromotility. Concentrations of salicylate equivalent to those that abolish spontaneous otoacoustic emissions in patients weaken the outer hair cell’s hydraulic skeleton. There is a significant diminution in the electromotile response associated with the loss in cell turgor. Aspirin’s effect on outer hair cell electromotility attests to the role of the outer hair cell in generating otoacoustic emissions and demonstrates how their physiology can influence the propagation of otoacoustic emissions. PMID:2187727

Brownell, William E.

2009-01-01

185

Sound Transmission through Cylindrical Shell Structures Excited by Boundary Layer Pressure Fluctuations  

NASA Technical Reports Server (NTRS)

This paper examines sound transmission into two concentric cylindrical sandwich shells subject to turbulent flow on the exterior surface of the outer shell. The interior of the shells is filled with fluid medium and there is an airgap between the shells in the annular space. The description of the pressure field is based on the cross-spectral density formulation of Corcos, Maestrello, and Efimtsov models of the turbulent boundary layer. The classical thin shell theory and the first-order shear deformation theory are applied for the inner and outer shells, respectively. Modal expansion and the Galerkin approach are used to obtain closed-form solutions for the shell displacements and the radiation and transmission pressures in the cavities including both the annular space and the interior. The average spectral density of the structural responses and the transmitted interior pressures are expressed explicitly in terms of the summation of the cross-spectral density of generalized force induced by the boundary layer turbulence. The effects of acoustic and hydrodynamic coincidences on the spectral density are observed. Numerical examples are presented to illustrate the method for both subsonic and supersonic flows.

Tang, Yvette Y.; Silcox, Richard J.; Robinson, Jay H.

1996-01-01

186

Development of hard x-ray optics at MSFC  

NASA Astrophysics Data System (ADS)

We are fabricating optics for the hard-x-ray region using electroform nickel replication. The attraction of this process, which has been widely used elsewhere, is that the resulting full shell optics are inherently stable and thus can have very good angular resolution. The challenge with this process is to develop lightweight optics, and to keep down the costs of mandrel fabrication. We accomplished the former through the development of high-strength, low-stress nickel alloys that permit very thin, stable, shells without fabrication- and handling-induced deformations. For the latter, we have utilized inexpensive grinding and diamond turning to figure the mandrels and then purpose-built polishing machines to finish the surface. In-house plating tanks and a simple water-bath separation system complete the process. To date we have built shells ranging in size from 5 cm diameter to 50 cm, and with thickness down to 100 micron. For our HERO balloon program, we are fabricating over 200 iridium-coated shells, 250 microns thick, for hard-x-ray imaging up to 75 keV. Early test results on these have indicated half-power-diameters of 15 arcsec. The status of these developments will be reviewed.

Ramsey, Brian D.; Elsner, Ronald F.; Engelhaupt, Darell E.; O'Dell, Stephen L.; Speegle, Chet O.; Weisskopf, Martin C.

2003-03-01

187

The development of hard x-ray optics at MSFC  

NASA Astrophysics Data System (ADS)

We have developed the electroformed-nickel replication process to enable us to fabricate light-weight, high-quality mirrors for the hard-x-ray region. Two projects currently utilizing this technology are the production of 240 mirror shells, of diameters ranging from 50 to 94 mm, for our HERO balloon payload, and 150- and 230-mm-diameter shells for a prototype Constellation-X hard-x-ray telescope module. The challenge for the former is to fabricate, mount, align and fly a large number of high-resolution mirrors within the constraints of a modest budget. For the latter, the challenge is to maintain high angular resolution despite weight-budget-driven mirror shell thicknesses (100 ?m) which make the shells extremely sensitive to fabrication and handling stresses, and to ensure that the replication process does not degrade the ultra-smooth surface finish (~3 Å) required for eventual multilayer coatings. We present a progress report on these two programs.

Ramsey, Brian D.; Elsner, Ron F.; Engelhaupt, Darell; Gubarev, Mikhail V.; Kolodziejczak, Jeffery J.; O'Dell, Stephen L.; Speegle, Chet O.; Weisskopf, Martin C.

2004-02-01

188

Sensational spherical shells  

NASA Astrophysics Data System (ADS)

Fluid-dynamic and capillary forces can be used to form nearly perfect, very small spherical shells when a liquid that can solidify is passed through an annular die to form an annular jet. Gravity and certain properties of even the most ideal materials, however, can cause slight asymmetries. The primary objective of the present work is the control of this shell formation process in earth laboratories rather than space microgravity, through the development of facilities and methods that minimize the deleterious effects of gravity, aerodynamic drag, and uncontrolled cooling. The spherical shells thus produced can be used in insulation, recyclable filter materials, fire retardants, explosives, heat transport slurries, shock-absorbing armor, and solid rocket motors.

Lee, M. C.; Kendall, J. M., Jr.; Bahrami, P. A.; Wang, T. G.

1986-01-01

189

CSI: Hard Drive  

ERIC Educational Resources Information Center

Acting on information from students who reported seeing a classmate looking at inappropriate material on a school computer, school officials used forensics software to plunge the depths of the PC's hard drive, searching for evidence of improper activity. Images were found in a deleted Internet Explorer cache as well as deleted file space.…

Sturgeon, Julie

2008-01-01

190

Hardness vs Randomness  

Microsoft Academic Search

We present a simple ne wc onstruction of a pseudorandom bit generator ,b ased on the constant depth generators of (N). It stretches a short string of truly random bits into a long string that looks random to an ya lgorithm from a comple xity class C (eg P, NC, PSPACE, ... )u sing an arbitrary function that is hard

Noam Nisan; Avi Wigderson

1994-01-01

191

Hard Times Hit Schools  

ERIC Educational Resources Information Center

Hard-to-grasp dollar amounts are forcing real cuts in K-12 education at a time when the cost of fueling buses and providing school lunches is increasing and the demands of the federal No Child Left Behind Act still loom larger over states and districts. "One of the real challenges is to continue progress in light of the economy," said Gale Gaines,…

McNeil, Michele

2008-01-01

192

Budgeting in Hard Times.  

ERIC Educational Resources Information Center

Interviews with school board members and administrators produced a list of suggestions for balancing a budget in hard times. Among these are changing calendars and schedules to reduce heating and cooling costs; sharing personnel; rescheduling some extracurricular activities; and forming cooperative agreements with other districts. (MLF)

Parrino, Frank M.

2003-01-01

193

Work Hard. Be Nice  

ERIC Educational Resources Information Center

In 1994, fresh from a two-year stint with Teach for America, Mike Feinberg and Dave Levin inaugurated the Knowledge Is Power Program (KIPP) in Houston with an enrollment of 49 5th graders. By this Fall, 75 KIPP schools will be up and running, setting children from poor and minority families on a path to college through a combination of hard work,…

Mathews, Jay

2009-01-01

194

Direct Observation of the Transition from Calcite to Aragonite Growth as Induced by Abalone Shell Proteins  

E-print Network

solutions of calcium carbonate. Past atomic force microscope studies of the interaction of these proteins. INTRODUCTION Abalone shells contain two distinct polymorphs of calcium carbonate. The outer portion calcium carbonate solutions (Belcher et al., 1996). Similar control of calcium carbonate polymorph has

Fygenson, Deborah Kuchnir

195

Application of a shell-shaped force sensor to a touch panel interface  

Microsoft Academic Search

The authors have developed a force-sensing mechanism composed of a force sensor device and an outer shell end-effector. The sensor can be used to sense force at any position on the body and calculate the position of a contact point without the need for a sensor array. The present study applies the force sensing mechanism as a haptic interface similar

Toshiaki Tsuji; Tatsuya Ito

2009-01-01

196

Magic numbers for metallic clusters and the principle of maximum hardness.  

PubMed Central

It is shown that for relatively more stable metallic clusters (those with magic number of atoms) the chemical hardness (I-A) too is relatively larger. Thus the occurrence of magic numbers for metal clusters whose stability is determined by their electronic shell structure can be understood as a manifestation of the principle of maximum hardness. This may also represent a possible way of delineating clusters with stability dominated by their electronic shell structure from those for which the magic numbers occur as a result of their geometric structure. PMID:11607276

Harbola, M K

1992-01-01

197

Incorporation of Heterologous Outer Membrane and Periplasmic Proteins into Escherichia coli Outer Membrane Vesicles  

Microsoft Academic Search

Gram-negative bacteria shed outer membrane vesi- cles composed of outer membrane and periplasmic com- ponents. Since vesicles from pathogenic bacteria con- tain virulence factors and have been shown to interact with eukaryotic cells, it has been proposed that vesicles behave as delivery vehicles. We wanted to determine whether heterologously expressed proteins would be in- corporated into the membrane and lumen

Nicole C. Kesty; Meta J. Kuehn

2004-01-01

198

Commissioning of the 4 K Outer Cryostat for the CUORE Experiment  

NASA Astrophysics Data System (ADS)

The Cryogenic Underground Observatory for Rare Events (CUORE) is a 1-ton scale bolometric experiment. The CUORE detector is an array of 988 TeO crystals arranged in a cylindrical, compact, and granular structure of 19 towers. These detectors will need a base temperature lower than 10 mK in order to meet the performance specifications. To cool the CUORE detector, a large cryogen free cryostat with five pulse tubes and one custom designed high power dilution refrigerator has been designed. The three vessels that form the outer shell of the CUORE cryostat were produced in 2012 and are now assembled in the Gran Sasso National Laboratories (LNGS). We report here the detailed description of the 4 K outer cryostat for the CUORE experiment together with the results of the validation tests done at the production site in 2012 and of the first commissioning to 4 K at LNGS in 2013.

Ferri, E.; Alessandria, F.; Biassoni, M.; Bucci, C.; Ceruti, G.; Chiarini, A.; Clemenza, M.; Cremonesi, O.; Datskov, V.; Dossena, S.; Faverzani, M.; Franceschi, M. A.; Gaigher, R.; Gorla, P.; Guetti, M.; Ligi, C.; Napolitano, T.; Nucciotti, A.; Pelosi, A.; Perego, M.; Previtali, E.; Sisti, M.; Taffarello, L.; Terranova, F.

2014-09-01

199

Statistical theory of correlations in random packings of hard particles  

E-print Network

A random packing of hard particles represents a fundamental model for granular matter. Despite its importance, analytical modeling of random packings remains difficult due to the existence of strong correlations which preclude the development of a simple theory. Here, we take inspiration from liquid theories for the $n$-particle angular correlation function to develop a formalism of random packings of hard particles from the bottom-up. A progressive expansion into a shell of particles converges in the large layer limit under a Kirkwood-like approximation of higher-order correlations. We apply the formalism to hard disks and predict the density of two-dimensional random close packing (RCP), $\\phi_{\\rm rcp} = 0.85\\pm0.01$, and random loose packing (RLP), $\\phi_{\\rm rlp} = 0.67\\pm0.01$. Our theory also predicts a phase diagram and angular correlation functions that are in good agreement with experimental and numerical data.

Yuliang Jin; James G. Puckett; Hernan A. Makse

2014-05-10

200

Prediction Model of the Outer Radiation Belt Developed by Chungbuk National University  

NASA Astrophysics Data System (ADS)

The Earth¡¯s outer radiation belt often suffers from drastic changes in the electron fluxes. Since the electrons can be a potential threat to satellites, efforts have long been made to model and predict electron flux variations. In this paper, we describe a prediction model for the outer belt electrons that we have recently developed at Chungbuk National University. The model is based on a one-dimensional radial diffusion equation with observationally determined specifications of a few major ingredients in the following way. First, the boundary condition of the outer edge of the outer belt is specified by empirical functions that we determine using the THEMIS satellite observations of energetic electrons near the boundary. Second, the plasmapause locations are specified by empirical functions that we determine using the electron density data of THEMIS. Third, the model incorporates the local acceleration effect by chorus waves into the one-dimensional radial diffusion equation. We determine this chorus acceleration effect by first obtaining an empirical formula of chorus intensity as a function of drift shell parameter L*, incorporating it as a source term in the one-dimensional diffusion equation, and lastly calibrating the term to best agree with observations of a certain interval. We present a comparison of the model run results with and without the chorus acceleration effect, demonstrating that the chorus effect has been incorporated into the model to a reasonable degree.

Shin, Dae-Kyu; Lee, Dae-Young; Kim, Jin-Hee; Cho, Jung-Hee

2014-12-01

201

Snail Shell Science.  

ERIC Educational Resources Information Center

Presents three inquiry-based lessons to develop the science process skills of observation, identification, and classification. Activities use whelk eggs and snail shells as the focus of the students' inquiries. Provides a list of 19 facts about whelks and snails. (MDH)

Matthews, Catherine

1992-01-01

202

Shell Creek Summers  

ERIC Educational Resources Information Center

In 2002 Shell Creek Watershed Improvement Group turned to the Newman Grove Public Schools' science department to help educate the public on water quality in the watershed and to establish a monitoring system that would be used to improve surface and groundwater quality in the creek's watershed. Nebraska Department of Environmental Quality provided…

Seier, Mark; Goedeken, Suzy

2005-01-01

203

THE ISOLATION OF RETINAL OUTER SEGMENT FRAGMENTS  

PubMed Central

Bovine retinal outer segment fragments were isolated by density gradient centrifugation in a high centrifugal field. Assays of the final preparation for enzymes of the mitochondrial respiratory chain indicated mitochondrial contamination not in excess of 1 per cent. Glucose-6-phosphatase and TPNH-cytochrome c reductase activities, presumably diagnostic for microsomes, were also absent. Electron micrographs did not disclose the presence of significant numbers of particles other than fragments of the outer segment discs. The red fragments were characterized by an ascorbate-oxidizing system and a high lipid content. PMID:4287275

McConnell, David G.

1965-01-01

204

Cochlear amplification, outer hair cells and prestin  

PubMed Central

Mechanical amplification of acoustic signals is apparently a common feature of vertebrate auditory organs. In non-mammalian vertebrates amplification is produced by stereociliary processes, related to the mechanotransducer channel complex and probably to the phenomenon of fast adaptation. The extended frequency range of the mammalian cochlea has likely co-evolved with a novel hair cell type, the outer hair cell and its constituent membrane protein, prestin. Cylindrical outer hair cells are motile and their somatic length changes are voltage driven and powered by prestin. One of the central outstanding problems in mammalian cochlear neurobiology is the relation between the two amplification processes. PMID:18809494

Dallos, Peter

2008-01-01

205

Is the outer Solar System chaotic?  

E-print Network

The existence of chaos in the system of Jovian planets has been in question for the past 15 years. Various investigators have found Lyapunov times ranging from about 5 millions years upwards to infinity, with no clear reason for the discrepancy. In this paper, we resolve the issue. The position of the outer planets is known to only a few parts in 10 million. We show that, within that observational uncertainty, there exist Lyapunov timescales in the full range listed above. Thus, the ``true'' Lyapunov timescale of the outer Solar System cannot be resolved using current observations.

Wayne B. Hayes

2007-02-07

206

Synthesis and characterization of hard magnetic composites—Hollow microsphere\\/titania\\/barium ferrite  

Microsoft Academic Search

Hard magnetic composites—hollow microsphere (core)\\/titania (intermediate layer)\\/barium ferrite (magnetic shell) (M\\/T\\/B) were prepared by wet-chemical method. Barium ferrite nanoparticles were directly coated on the rutile titania-coated hollow microsphere forming light hard magnetic composites using sol–gel technique. The prepared composites were characterized with FESEM, EDS, XRD and vibrating sample magnetometry. The composites are composed of barium ferrite, hematite, titania and mullite.

Guohong Mu; Xifeng Pan; Na Chen; Chihuan He; Mingyuan Gu

2008-01-01

207

Three-dimensional simulation of energetic outer zone electron dynamics due to wave-particle interaction and azimuthal advection  

Microsoft Academic Search

We present a three-dimensional code treating the local resonant interaction with various waves and azimuthal advection around the Earth to evaluate storm-time energetic outer zone electron phase space density (PSD) evolution at a constant L shell without radial diffusion. Assuming a model distribution of wave characteristics at L = 4.5, we show that energetic (˜MeV) electron PSD can decrease by

Zhenpeng Su; Huinan Zheng; Shui Wang

2010-01-01

208

Three-dimensional simulation of energetic outer zone electron dynamics due to wave-particle interaction and azimuthal advection  

Microsoft Academic Search

We present a three-dimensional code treating the local resonant interaction with various waves and azimuthal advection around the Earth to evaluate storm-time energetic outer zone electron phase space density (PSD) evolution at a constant L shell without radial diffusion. Assuming a model distribution of wave characteristics at L = 4.5, we show that energetic (?MeV) electron PSD can decrease by

Zhenpeng Su; Huinan Zheng; Shui Wang

2010-01-01

209

Prevention of the Outer Space Weaponization  

NASA Astrophysics Data System (ADS)

9 states. The satellites of various functions (early warning, communication, data acquisition, reconnaissance and navigation) were actively used and continue to be used with the purposes of raising efficiency of ground armed forces, especially in fight against international terrorism. At the same time such satellites are not a weapon in the sense of that word since they do not create the threats of armed attack in outer space or from outer space. Moreover, they promote maintaining of stability in the international relations. For this reason the reconnaissance and data acquisition satellites used for the verification of observance by States of the arms limitation agreements are under international protection as national technical means of the control. Similar protection is enjoyed by the early warning satellites. With the help of space communication facilities the more reliable operative connection of the statesmen is organized in the strained situations. By this way the probability of making of the incorrect retaliatory decisions in critical political situations is reduced. At the same time it's necessary to take into consideration that the activities of such satellite systems are tightly connected with ground armed forces of the states. the earth, what from the point of view of international law may be qualified as establishing a partial demilitarization regime in outer space. After the prohibition of anti-satellite weapons (ASAT) and anti-satellite (ASAT) weapons it will be possible to speak about establishing of an international legal regime of complete demilitarization in outer space eliminating any kinds of weapon from outer space. in a peaceful time. weaponization.The main task of this paper is to analyze and to discuss the present binding regime of the outer space deweaponization and particular measures on consolidation and strengthening of this regime. agreements of the Russian Federation and the USA into multilateral Treaties. Such "immunity" would cover all operating space objects, irrespective of their military or civil designation. This approach is quite justified taking into consideration that military sattelites enhanced international peace and security and had broad advantages, such as treaty compliance and monitoring, the global positioning system, counter-terrorism and sanctions enforcement. Many examples of the last years demonstrate the tendency of engagement of military satellites into commercial space services. transparency on the pre-launch stage of space activity, including satellite inspection before ignition. Objects Flight Path Tracking. implemantation of a non-use of force and threat of force - a fundamental principle of modern international law. This implies the application of the menshened principle of international law by means of a treaty to the outer space activities with reference to the actions made in outer space, or directed from outer space against targets on the Earth as well as directed from the Earth against objects moving in outer space. to the possibility of conclusion in future of a multilateral arrangement on the prohibition of the space-based ABM. Accordingly, it is discussed the problem of an efficient international control over the prohibition of placement of the above mentioned weapons into outer space. to the challenges of the new millennium. 8

Zhukov, Gennady P.

2002-01-01

210

Eat Smart. Play Hard.  

NSDL National Science Digital Library

The Food and Nutrition Service of the US Department of Agriculture offers online educational material as part of "Eat Smart. Play Hard." -- a public information campaign designed to promote healthy living in American children. While the site and its materials are geared for use by state and local program coordinators, anyone is welcome to download the available information and activity sheets. Click on Cool Stuff for Kids for nutrition-related puzzles and games. Parents Place offers informational brochures and an educational bookmark.

211

Sea shells and blood cells  

NSDL National Science Digital Library

Scientists know that oysters make their shells from crystals but where the crystals are made is still a mystery. A new study in the 09 April 2004 issue of the journal Science suggests that these shell-building crystals are formed in a special class of blood cells that travel to the site of shell formation and unload their crystal cargo.

American Association for the Advancement of Science (AAAS; )

2004-04-09

212

Recent Advances in Shell Evolution with Shell-Model Calculations  

E-print Network

Shell evolution in exotic nuclei is investigated with large-scale shell-model calculations. After presenting that the central and tensor forces produce distinctive ways of shell evolution, we show several recent results: (i) evolution of single-particle-like levels in antimony and cupper isotopes, (ii) shape coexistence in nickel isotopes understood in terms of configuration-dependent shell structure, and (iii) prediction of the evolution of the recently established $N=34$ magic number towards smaller proton numbers. In any case, large-scale shell-model calculations play indispensable roles in describing the interplay between single-particle character and correlation.

Yutaka Utsuno; Takaharu Otsuka; Yusuke Tsunoda; Noritaka Shimizu; Michio Honma; Tomoaki Togashi; Takahiro Mizusaki

2014-09-16

213

SUPER HARD SURFACED POLYMERS  

SciTech Connect

High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

Mansur, Louis K [ORNL] [ORNL; Bhattacharya, R [UES, Incorporated, Dayton, OH] [UES, Incorporated, Dayton, OH; Blau, Peter Julian [ORNL] [ORNL; Clemons, Art [ORNL] [ORNL; Eberle, Cliff [ORNL] [ORNL; Evans, H B [UES, Incorporated, Dayton, OH] [UES, Incorporated, Dayton, OH; Janke, Christopher James [ORNL] [ORNL; Jolly, Brian C [ORNL] [ORNL; Lee, E H [Consultant, Milpitas, CA] [Consultant, Milpitas, CA; Leonard, Keith J [ORNL] [ORNL; Trejo, Rosa M [ORNL] [ORNL; Rivard, John D [ORNL] [ORNL

2010-01-01

214

Design of multiple-shell gas nozzles for refurbished Z.  

SciTech Connect

This paper presents initial designs of multiple-shell gas puff imploding loads for the refurbished Z generator. The nozzle has three independent drivers for three independent plena. The outer and middle plena may be charged to 250psia whilst the central jet can be charged to 1000psia. 8-cm and 12-cm outer diameter nozzles have been built and tested on the bench. The unique valve design provides a very fast opening, hence the amount of stray gas outside the core nozzle flow is minimized. A similar 8-cm nozzle was characterized earlier using a fiber optic interferometer, but at lower pressures and without the central jet. Those data have been scaled to the higher pressures required for refurbished Z and used to estimate performance. The use of three independent plena allows variation of the pressure (hence mass distribution) in the nozzle flow, allowing optimization of implosion stability and the on-axis mass that most contributes to K-shell emission. Varying the outer/middle mass ratios influences the implosion time and should affect the details of the assembly on axis as well as the radiation physics. Varying the central jet pressure will have a minor effect on implosion dynamics, but a strong effect on pinch conditions and radiation physics. Optimum mass distributions for planned initial Ar shots on refurbished Z are described. Additional interferometer data including the central jet and at higher pressures will also be presented.

Giuliani, J. L. (Naval Research Laboratory, Washington DC); Waisman, Eduardo Mario; Velikovich, Aleksandr Lazarevich (Naval Research Laboratory, Washington DC); Madden, R. (Alameda Applied Sciences Corporation, San Leandro, CA); Thornhill, W. (Naval Research Laboratory, Washington DC); Ampleford, David J.; Krishnan, Mahadevan (Alameda Applied Sciences Corporation, San Leandro, CA); Coleman, P. L.; Cuneo, Michael Edward; Wilson Elliott, Kristi (Alameda Applied Sciences Corporation, San Leandro, CA); Coverdale, Christine Anne; Clark, R. (Naval Research Laboratory, Washington DC); Jones, Brent Manley

2010-06-01

215

Isolation and Characterization of the Outer Membrane of Borrelia hermsii  

Microsoft Academic Search

The outer membrane of Borrelia hermsii has been shown by freeze-fracture analysis to contain a low density of membrane-spanning outer membrane proteins which have not yet been isolated or identified. In this study, we report the purification of outer membrane vesicles (OMV) from B. hermsii HS-1 and the subsequent identification of their constituent outer membrane proteins. The B. hermsii outer

ELLEN S. SHANG; JONATHAN T. SKARE; MAURICE M. EXNER; DAVID R. BLANCO; BRUCE L. KAGAN; JAMES N. MILLER; MICHAEL A. LOVETT

216

Natural melting within a spherical shell  

NASA Technical Reports Server (NTRS)

Fundamental heat transfer experiments were performed on the melting of a phase change medium in a spherical shell. Free expansion of the medium into a void space within the sphere was permitted. A step function temperature jump on the outer shell wall was imposed and the timewise evolution of the melting process and the position of the solid-liquid interface was photographically recorded. Numerical integration of the interface position data yielded information about the melted mass and the energy of melting. It was found that the rate of melting and the heat transfer were significantly affected by the movement of the solid medium to the base of the sphere due to gravity. The energy transfer associated with melting was substantially higher than that predicted by the conduction model. Furthermore, the radio of the measured values of sensible energy in the liquid melt to the energy of melting were nearly proportional to the Stefan number. The experimental results are in agreement with a theory set forth in an earlier paper.

Bahrami, Parviz A.

1990-01-01

217

Surface scattering of core-shell particles with anisotropic shell.  

PubMed

The Bobbert-Vlieger solution to light scattering of a spherical particle suspended above a surface is extended to model the scattering of core-shell structures with anisotropic shell. Numerical modeling demonstrates that ellipsometry has potential to resolve particle shell anisotropy down to 1.8×10(-4) for SiO(2)@Au core-shell particles in air with 50 nm core diameter and 10 nm shell thickness deposited on a silicon Si [100] substrate with a density of 1???m(-2). Application of the Ibrahim and Bashara criterion for ellipsometer parameter cross correlation identifies variable-angle ellipsometry as a viable experimental approach to separate particle core radius and shell thickness from the shell anisotropy. Ellipsometry is also identified as an alternative technique for determination of liposome anisotropy and for the study of liposome fusion with a substrate in the formation process of supported lipid bilayers. PMID:24561952

De Beule, Pieter A A

2014-01-01

218

Wave observations in outer planet magnetospheres  

Microsoft Academic Search

The first measurements of plasma waves and wave-particle interactions in the magnetospheres of the outer planets were provided by instruments on Voyager 1 and 2. At Jupiter, the observations yielded new information on upstream electrons and ions, bow shock dissipation processes, trapped radio waves in the magnetospheres and extended Jovian magnetotail, pitch angle diffusion mechanisms and whistlers from atmospheric lightning.

F. L. Scarf

1985-01-01

219

BIOREACTOR DESIGN - OUTER LOOP LANDFILL, LOUISVILLE, KY  

EPA Science Inventory

Bioreactor field demonstration projects are underway at the Outer Loop Landfill in Louisville, KY, USA. The research effort is a cooperative research effort between US EPA and Waste Management Inc. Two primary kinds of municipal waste bioreactors are under study at this site. ...

220

Ground Based Studies of the Outer Planets  

NASA Technical Reports Server (NTRS)

This report covers progress to date under this grant on our continuing program to conduct ground based studies of the outer solar system planets and satellites, with emphasis on spectroscopy and atmospheric phenomena. The research continues under our new PAST grant, NNG04G131G beginning 5/1/2004. The original period of performance of the subject grant was 3/1/2001 to 2/28/2004, but was extended one year at no cost. Although there is some overlap in the scientific projects conducted during the extended year with those of the new grant, this report is confined to the portion of the work funded under NAG5-10435. The primary goals for this grant period were a comparative study of outer planet thermospheres/ionospheres near solar maximum, extended to the mid-IR, and the investigation of molecular dimers in outer solar system atmospheres. This project supports NASA's planned space missions, Jupiter Polar Orbiter, outer Planet Microprobes, and the recent Cassini flyby of Jupiter. It also supports the OSS strategic plan themes, The Exploration of the Solar System and The Sun-Earth Connection/ Understanding comparative planetary space environments.

Trafton, Laurence M.

2005-01-01

221

Spirituality and Education; Inner and Outer Realities  

ERIC Educational Resources Information Center

There is a persisting tendency in attempts to define spirituality, to adopt a dualistic point of view which sees the spirit as somehow impenetrably inner, innate and introspectively perceived, interacting with the outer world through the body. As well as a strong intuitive sense of the correctness of this philosophical point of view, it also is…

Radford, Mike

2006-01-01

222

THE ORBITS OF THE OUTER URANIAN SATELLITES  

SciTech Connect

We report on the numerically integrated orbits for the nine outer Uranian satellites. The orbits are calculated based on fits to the astrometric observations for the period from 1984 to 2006. The results include the state vectors, post-fit residuals, and mean orbital elements. We also assess the accuracy of the orbital fits and discuss the need for future measurements.

Brozovic, M.; Jacobson, R. A. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States)], E-mail: marina.brozovic@jpl.nasa.gov

2009-04-15

223

The magnetospheres of the outer planets  

SciTech Connect

Research on the magnetospheres of all of the outer planets including Jupiter, Uranus, Neptune, and Pluto is reviewed for the 1987-1990 time period. Particular attention is given to magnetospheric structure, plasma transport, Jovian aurora, Io and the plasma torus, Titan and its magnetospheric interactions, rings and dusty plasmas, magnetospheric convection, and satellite interactions.

Mcnutt, R.L., Jr. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

1991-01-01

224

Structural basis for outer membrane lipopolysaccharide insertion.  

PubMed

Lipopolysaccharide (LPS) is essential for most Gram-negative bacteria and has crucial roles in protection of the bacteria from harsh environments and toxic compounds, including antibiotics. Seven LPS transport proteins (that is, LptA-LptG) form a trans-envelope protein complex responsible for the transport of LPS from the inner membrane to the outer membrane, the mechanism for which is poorly understood. Here we report the first crystal structure of the unique integral membrane LPS translocon LptD-LptE complex. LptD forms a novel 26-stranded ?-barrel, which is to our knowledge the largest ?-barrel reported so far. LptE adopts a roll-like structure located inside the barrel of LptD to form an unprecedented two-protein 'barrel and plug' architecture. The structure, molecular dynamics simulations and functional assays suggest that the hydrophilic O-antigen and the core oligosaccharide of the LPS may pass through the barrel and the lipid A of the LPS may be inserted into the outer leaflet of the outer membrane through a lateral opening between strands ?1 and ?26 of LptD. These findings not only help us to understand important aspects of bacterial outer membrane biogenesis, but also have significant potential for the development of novel drugs against multi-drug resistant pathogenic bacteria. PMID:24990744

Dong, Haohao; Xiang, Quanju; Gu, Yinghong; Wang, Zhongshan; Paterson, Neil G; Stansfeld, Phillip J; He, Chuan; Zhang, Yizheng; Wang, Wenjian; Dong, Changjiang

2014-07-01

225

Outer-shell excitation mechanisms and static-mode laser-fluorescence spectroscopy of sputtered atoms  

SciTech Connect

A review of the literature on atoms sputtered in electronically excited states is given together with a discussion of various mechanisms that have been proposed to account for the observations. The major observational features that have emerged from the older studies may be summarized as follows: (1) the kinetic energies of neutral atoms in highly excited electronic states are 1-2 orders of magnitude greater than E/sub b/, the surface binding energy; (2) relative yields show approximately exponential dependence on excitation energy with characteristic temperatures measured in thousands of degrees; (43) absolute yields are lower by 2-3 orders of magnitude than secondary ion yields which themselves are usually very small compared to total sputtering yields. In many cases, excited-state yields increase 1-2 orders of magnitude as a result of surface oxidation. 83 references.

Gruen, D.M.; Pellin, M.J.; Young, C.E.; Mendelsohn, M.H.; DeWald, A.B.

1982-01-01

226

HST/ACS observations of shell galaxies: inner shells, shell colours and dust  

E-print Network

AIM:Learn more about the origin of shells and dust in early type galaxies. METHOD: V-I colours of shells and underlying galaxies are derived, using HST Advanced Camera for Surveys (ACS) data. A galaxy model is made locally in wedges and subtracted to determine shell profiles and colours. We applied Voronoi binning to our data to get smoothed colour maps of the galaxies. Comparison with N-body simulations from the literature gives more insight to the origin of the shell features. Shell positions and dust characteristics are inferred from model galaxy subtracted images. RESULT: The ACS images reveal shells well within the effective radius in some galaxies (at 1.7 kpc in the case of NGC 5982). In some cases, strong nuclear dust patches prevent detection of inner shells. Most shells have colours which are similar to the underlying galaxy. Some inner shells are redder than the galaxy. All six shell galaxies show out of dynamical equilibrium dust features, like lanes or patches, in their central regions. Our detection rate for dust in the shell ellipticals is greater than that found from HST archive data for a sample of normal early-type galaxies, at the 95% confidence level. CONCLUSIONS: The merger model describes better the shell distributions and morphologies than the interaction model. Red shell colours are most likely due to the presence of dust and/or older stellar populations. The high prevalence and out of dynamical equilibrium morphologies of the central dust features point towards external influences being responsible for visible dust features in early type shell galaxies. Inner shells are able to manifest themselves in relatively old shell systems.

G. Sikkema; D. Carter; R. F. Peletier; M. Balcells; C. del Burgo; E. A. Valentijn

2007-03-22

227

The Outer Atmosphere of Mira Variables  

NASA Astrophysics Data System (ADS)

We propose to use FUSE to probe the temperature-density structure of the shocked atmospheres of long-period variable (Mira-type) stars. For the first time, FUSE gives us the capabilities to study the outer shocked region of the atmosphere using the hydrogen Lyman lines. At 5 separate phases, we wish to obtain MDRS spectra of the Lyman series from Lybeta to the Lyman limit (1030AA --- 912AA) for the warm Mira star, SCar. With these spectra, we will make comparisons (1) between Lyman flux (and possibly H_2 emission) variability and the variability in the UV emission lines and hydrogen Balmer lines using previously obtained HST HRS, IUE, and ground-based optical spectra at coincident phases to the FUSE observations to study the effect that the radiation field from the lower, hotter shocks (where Mg 2 and the Balmer lines form) have on the upper shocked region (where the Lyman lines form), and (2) to synthetic spectra from representative dynamic models we have generated. These NLTE radiative transfer calculations have shown that the radiation field of the inner shocks dominate the ionization throughout the entire atmosphere. The calculations also have shown that the Lyman emission lines form in the outer reaches of the atmosphere where the shocks are much weaker as they propagate outward. This is the first time such a diagnostic has been measured for the outer atmosphere of these stars. It also gives us a pioneering attempt to record the suspected strong FUV H_2 in emission. Such an observation will have strong constraints on the atmospheric structure of the outer layers of these stars. Finally, it is imperative to obtain fairly high dispersion (R approx 10,000) spectra of the Lyman lines in Miras, since these lines are fundamental in the understanding of the energy flow in their outer atmosphere, and of mass loss in this critical stage of a stars evolution.

Luttermoser, Donald G.

228

On the influence of a translating inner core in models of outer core convection  

NASA Astrophysics Data System (ADS)

It has recently been proposed that the hemispheric seismic structure of the inner core can be explained by a self-sustained rigid-body translation of the inner core material, resulting in melting of the solid at the leading face and a compensating crystallisation at the trailing face. This process induces a hemispherical variation in the release of light elements and latent heat at the inner-core boundary, the two main sources of thermochemical buoyancy thought to drive convection in the outer core. However, the effect of a translating inner core on outer core convection is presently unknown. In this paper we model convection in the outer core with a nonmagnetic Boussinesq fluid in a rotating spherical shell driven by purely thermal buoyancy, incorporating the effect of a translating inner core by a time-independent spherical harmonic degree and order 1 (Y11) pattern of heat-flux imposed at the inner boundary. The analysis considers Rayleigh numbers up to 10 times the critical value for onset of nonmagnetic convection, a parameter regime where the effects of the inhomogeneous boundary condition are expected to be most pronounced, and focuses on varying q?, the amplitude of the imposed boundary anomalies. The presence of inner boundary anomalies significantly affects the behaviour of the model system. Increasing q? leads to flow patterns dominated by azimuthal jets that span large regions of the shell where radial motion is significantly inhibited. Vigorous convection becomes increasingly confined to isolated regions as q? increases; these regions do not drift and always occur in the hemisphere subjected to a higher than average boundary heat-flux. Effects of the inner boundary anomalies are visible at the outer boundary in all inhomogeneous models considered. At low q? the expression of inner boundary effects at the core surface is a difference in the flow speed between the two hemispheres. As q? increases the spiralling azimuthal jets driven from the inner boundary are clearly visible at the outer boundary. Finally, our results suggest that, when the system is heated from below, a Y11 heat-flux pattern imposed on the inner boundary has a greater overall influence on the spatio-temporal behaviour of the flow than the same pattern imposed at the outer boundary.

Davies, C. J.; Silva, L.; Mound, J.

2013-01-01

229

Hardness of Materials- Introduction  

NSDL National Science Digital Library

This lesson plan from Edmonds Community College will serve as an excellent introduction to the hardness of materials. The module illustrates the differences in properties between different materials. Students will determine property differences between different types of materials, observe property differences between materials of the same class, measure, record and report their results and observe differences in results due to operator error. Student, instructor and course evaluation questions are included. This document will serve as a framework for instructors and may be downloaded in PDF format.

230

Hard metal composition  

DOEpatents

A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 weight percent boron carbide and the remainder a metal mixture comprising from 70 to 90 percent tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 to 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

Sheinberg, Haskell (Los Alamos, NM)

1986-01-01

231

Hard physics in PHENIX  

E-print Network

We review recent results on hard observables in p+p, d+A and A+A collisions obtained by the PHENIX experiment. Emphasis is put on those measurements that provide insight into the properties of hot QCD media expected to be created in nucleus-nucleus collisions at RHIC energies. Direct photon spectra, jet properties and heavy quarks production measured in p+p and d+Au collisions are compared to the same observables extracted in heavy ion collisions to find modifications due to the presence of hot QCD matter.

D. Peressounko; for the PHENIX collaboration

2005-12-08

232

Hard diffraction in CDF  

SciTech Connect

The aim of these studies is to use hard (large Q{sup 2}) processes to investigate the partonic nature of the pomeron. We have measured events with large rapidity gaps between balancing high E{sub T} jets, events with two forward (same-side) jets and a large gap (diffractive di-jet production), diffractive W{sup {+-}} production and diffractive heavy flavor (J/{psi} and b-quark) production. Candidate events of the type double-pomeron {yields} di-jet are observed. I close with a look at the future (Run II).

Albrow, M.G.; CDF Collaboration

1997-10-01

233

Outer Retinal Structure in Patients with Acute Zonal Occult Outer Retinopathy  

Microsoft Academic Search

PurposeTo correlate visual function with high-resolution images of retinal structure using adaptive optics scanning laser ophthalmoscopy (AOSLO) in 4 patients with acute zonal occult outer retinopathy (AZOOR).

Marianna Mkrtchyan; Brandon J. Lujan; David Merino; Charles E. Thirkill; Austin Roorda; Jacque L. Duncan

234

76 FR 63654 - Outer Continental Shelf Official Protraction Diagram, Lease Maps, and Supplemental Official Outer...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Shelf Official Protraction Diagram, Lease Maps, and Supplemental Official Outer Continental...Official Protraction Diagram (OPD), Lease Maps, and Supplemental Official OCS Block Diagrams...OCS Official Protraction Diagram, Lease Maps, and Supplemental Official OCS Shelf...

2011-10-13

235

76 FR 2919 - Outer Continental Shelf Official Protraction Diagram and Supplemental Official Outer Continental...  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF THE INTERIOR Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf...Shelf Block Diagrams AGENCY: Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE),...

2011-01-18

236

Bioluminescent signals spatially amplified by wavelength-specific diffusion through the shell of a marine snail  

PubMed Central

Some living organisms produce visible light (bioluminescence) for intra- or interspecific visual communication. Here, we describe a remarkable bioluminescent adaptation in the marine snail Hinea brasiliana. This species produces a luminous display in response to mechanical stimulation caused by encounters with other motile organisms. The light is produced from discrete areas on the snail's body beneath the snail's shell, and must thus overcome this structural barrier to be viewed by an external receiver. The diffusion and transmission efficiency of the shell is greater than a commercial diffuser reference material. Most strikingly, the shell, although opaque and pigmented, selectively diffuses the blue-green wavelength of the species bioluminescence. This diffusion generates a luminous display that is enlarged relative to the original light source. This unusual shell thus allows spatially amplified outward transmission of light communication signals from the snail, while allowing the animal to remain safely inside its hard protective shell. PMID:21159673

Deheyn, Dimitri D.; Wilson, Nerida G.

2011-01-01

237

On a site-specific delivery system based on core-shell structured magnetic particles: Preparation and characterization  

NASA Astrophysics Data System (ADS)

In the present work, core-shell structured submicro particles with light-switch of azobenzene were developed as a site-specific delivery system. The core was composed of magnetic Fe3O4 submicro particles, providing the magnetism-guiding and targeting function, and the outer shell was composed of mesoporous silica structure, providing solid mesoporous channels, large surface area, tunable pore sizes and volumes for cargo molecules. The light switch of azobenzene was covalently grafted onto the backbone of the outer shell. The core-shell structured submicro particles were characterized and identified by SEM, TEM, XRD, IR spectra, N2 adsorption/desorption isotherms, UV-Vis absorption and emission spectra. Experiment data confirmed the successful preparation of core-shell structured submicro particles with light-switch of azobenzene. The magnetic core was as wide as ˜160 nm and the outer shell was found to own mesopores to load cargo molecules. The controllable release character of these submicro particles was also investigated. With the help of light-switch of azobenzene, controllable release of cargo molecules was successfully realized.

Chen, Meng; Zhang, Dong; Xu, Ming Hua; Zhao, Shu Qing; Sun, Cai Xia

2013-12-01

238

First Images from HERO: A Hard-X-Ray Focusing Telescope  

NASA Technical Reports Server (NTRS)

We are developing a balloon-borne hard-x-ray telescope that utilizes grazing incidence optics. Termed HERO, for High-Energy Replicated Optics, the instrument will provide unprecented sensitivity in the hard-x-ray region and will achieve milliCrab-level sensitivity in a typical 3-hour balloon-flight observation and 50 microCrab sensitivity on ultra-long-duration flights. A recent proof-of-concept flight, featuring a small number of mirror shells captured the first focused hard-x-ray images of galactic x-ray sources. Full details of the payload, its expected future performance and its recent measurements are provided.

Ramsey, Brian D.; Alexander, Cheryl D.; Apple, Jeff A.; Benson, Carl M.; Dietz, Kurtis L.; Elsner, Ronald F.; Engelhaupt, Darell E.; Ghosh, Kajal K.; Kolodziejczak, Jeffery J.; ODell, Stephen L.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

239

Drift shells and aurora computed using the O8 magnetic field model for Neptune  

NASA Technical Reports Server (NTRS)

Charged particle drift shells are calculated using the O8 magnetic field model for Neptune. Inner drift shell morphologies differ significantly from dipolar drift shells for the parts of drift shells inward of r = 2 R(sub N). Outer drift shells (L approx. greater than 10), when traced down to Neptune's surface following magnetic field lines, are simple closed loops around magnetic poles. Inner drift shells (L approx. less than 4), on the other hand, when traced to the surface, are also single loops but stretched in a previously unknown way: sometimes with a cusp and sometimes into two joined loops. Inner drift shell footprints on R = 1 provide the basis for identifying precipitation L shells, interpreting observed aurora, and predicting additional emissions on that part of Neptune's surface unobserved by the Ultraviolet Spectrometer (UVS). Precipitation in a global magnetic anomaly, `ordinary' auroral precipitation near the south magnetic pole, and precipitation from field lines with no magnetic field minimum above Neptune's exobase collectively appear to account for all of the observed auroral emission regions at Neptune. To the extent that aurora can be understood in this model, it is suggested O8 may be reasonably accurate.

Paranicas, C.; Cheng, A. F.

1994-01-01

240

Dynamics of a suspension of interacting yolk-shell particles  

E-print Network

In this work we study the self-diffusion properties of a liquid of hollow spherical particles (shells)bearing a smaller solid sphere in their interior (yolks). We model this system using purely repulsive hard-body interactions between all (shell and yolk) particles, but assume the presence of a background ideal solvent such that all the particles execute free Brownian motion between collisions,characterized by short-time self-diffusion coefficients D0s for the shells and D0y for the yolks. Using a softened version of these interparticle potentials we perform Brownian dynamics simulations to determine the mean squared displacement and intermediate scattering function of the yolk-shell complex. These results can be understood in terms of a set of effective Langevin equations for the N interacting shell particles, pre-averaged over the yolks' degrees of freedom, from which an approximate self-consistent description of the simulated self-diffusion properties can be derived. Here we compare the theoretical and sim...

Díaz, L E Sánchez; Li, X; Chen, Wei-Ren; Medina-Noyola, M

2014-01-01

241

Myxobacteria Produce Outer Membrane-Enclosed Tubes in Unstructured Environments  

PubMed Central

Myxobacteria are social microbes that exhibit complex multicellular behaviors. By use of fluorescent reporters, we show that Myxococcus xanthus isolates produce long narrow filaments that are enclosed by the outer membrane (OM) and contain proteins. We show that these OM tube (OMT) structures are produced at surprisingly high levels when cells are placed in liquid medium or buffer without agitation. OMTs can be long and easily exceed multiple cell lengths. When viewed by transmission electron microscopy, their morphology varies between tubes and chain-like structures. Intermediate-like structures are also found, suggesting that OMTs may transition between these two morphotypes. In support of this, video epifluorescence microscopy found that OMTs in solution dynamically twist and jiggle. On hard surfaces, myxobacteria glide, and upon cell-cell contact, they can efficiently exchange their OM proteins and lipids by a TraAB-dependent mechanism. Although the structure of OMTs hints at a possible role as conduits for exchange, evidence is presented to the contrary. For example, abundant OMT production occurs in traA or traB mutants and when cells are grown in liquid medium, yet transfer cannot occur under these conditions. Thus, genetic and environmental conditions that promote OMT production are incongruent with OM exchange. PMID:24391054

Wei, Xueming; Vassallo, Christopher N.; Pathak, Darshankumar T.

2014-01-01

242

Ultrastructural immunolocalization of alpha-keratins and associated beta-proteins (beta-keratins) suggests a new interpretation on the process of hard and soft cornification in turtle epidermis.  

PubMed

The epidermis of soft-shelled and hard-shelled turtles has been compared to determine the origin of the different cornification. Immunolocalization of acidic alpha-keratin (AK2) of 45-50 kDa in tonofilaments of the epidermis in Apalone spinifera and absence in the corneous layer where desquamating corneocytes are present supports the biochemical data. Corneocytes shows a weak to absent immunolabeling for beta-proteins (formerly beta-keratins) of 14-16 kDa while sparse immunolabeled corneous granules are seen in the pre-corneous layer. In the hard-shelled turtle Pseudemys nelsonii differentiating corneocytes contain small level of acidic alpha-keratin while beta-proteins of 10-17 kDa form dense aggregates of corneous material among tonofilaments. Corneocytes do not desquamate but remain tightly connected determining an increase in thickness of the corneous layer that becomes mechanically stiff and resistant. Since both species possess beta-proteins in shelled and non-shelled areas of the epidermis the difference in hardness of the corneous layer is not due to the alternation between beta-keratin versus alpha-keratin. Mechanical resilience of the corneous layer derives from the accumulation of alpha-keratins, beta- and likely of other proteins in corneocytes of the shell in hard-shelled turtles. In the softer epidermis of hard-shelled turtles and in the soft-shelled turtle a more rapid and continuous turnover of corneocytes is present and no accumulation of beta-proteins and corneocytes takes place. It is hypothesized that the dermis derived from the carapacial ridge during development remains localized underneath the shell epidermis in hard-shelled turtles and influences the formation of the hard corneous epidermis. PMID:23958576

Alibardi, L

2013-01-01

243

Hard Metal Disease  

PubMed Central

In Great Britain there have been no published reports of respiratory disease occurring amongst workers in the hard metal (tungsten carbide) industry. In this paper the clinical and radiological findings in six cases and the pathological findings in one are described. In two cases physiological studies indicated mild alveolar diffusion defects. Histological examination in a fatal case revealed diffuse pulmonary interstitial fibrosis with marked peribronchial and perivascular fibrosis and bronchial epithelial hyperplasia and metaplasia. Radiological surveys revealed the sporadic occurrence and low incidence of the disease. The alterations in respiratory mechanics which occurred in two workers following a day's exposure to dust are described. Airborne dust concentrations are given. The industrial process is outlined and the literature is reviewed. The toxicity of the metals is discussed, and our findings are compared with those reported from Europe and the United States. We are of the opinion that the changes which we would describe as hard metal disease are caused by the inhalation of dust at work and that the component responsible may be cobalt. Images PMID:13970036

Bech, A. O.; Kipling, M. D.; Heather, J. C.

1962-01-01

244

The role of the zebra mussel ( Dreissena polymorpha ) in structuring macroinvertebrate communities on hard substrata  

Microsoft Academic Search

We examined the importance of the Eurasian zebra mussel (Dreissena polymorpha) in structuring macroinvertebrate communities on hard substrata in the Great Lakes - St. Lawrence River system. An experiment using artificial substrata (i.e., cement bricks with either a layer of living zebra mussels, a layer of intact empty shells that mimicked living mussels, or with no added layer) showed that

Anthony Ricciardi; Fred G. Whoriskey; Joseph B. Rasmussen

1997-01-01

245

Laser sintering (SLS) of hard metal powders for abrasion resistant coatings  

Microsoft Academic Search

Selective laser sintering (SLS), one of the new RP, RT and RM techniques, may be able to provide a process to form hard coating, which increases the life of machine parts in abrasive conditions. It is known that cemented carbide (WC–Co) parts can be made by this technology, although not to full density. A porous shell of WC–Co, shaped to

K Maeda; T. H. C Childs

2004-01-01

246

Boundary layers of the earth's outer magnetosphere  

NASA Technical Reports Server (NTRS)

The magnetospheric boundary layer and the plasma-sheet boundary layer are the primary boundary layers of the earth's outer magnetosphere. Recent satellite observations indicate that they provide for more than 50 percent of the plasma and energy transport in the outer magnetosphere although they constitute less than 5 percent by volume. Relative to the energy density in the source regions, plasma in the magnetospheric boundary layer is predominantly deenergized whereas plasma in the plasma-sheet boundary layer has been accelerated. The reconnection hypothesis continues to provide a useful framework for comparing data sampled in the highly dynamic magnetospheric environment. Observations of 'flux transfer events' and other detailed features near the boundaries have been recently interpreted in terms of nonsteady-state reconnection. Alternative hypotheses are also being investigated. More work needs to be done, both in theory and observation, to determine whether reconnection actually occurs in the magnetosphere and, if so, whether it is important for overall magnetospheric dynamics.

Eastman, T. E.; Frank, L. A.

1984-01-01

247

Three-dimensional structure of single-shelled bluetongue virus.  

PubMed Central

The three-dimensional structure of single-shelled bluetongue virus has been determined to a resolution of 3 nm by using electron cryomicroscopy and image-processing techniques. The single-shelled virion has a diameter of 69 nm. The three-dimensional structure of the virion has icosahedral symmetry with a triangulation number of 13 in a left-handed configuration. The three-dimensional structure can be described in terms of two concentric layers of density surrounding a central core density. Two distinctive features of the outer layer are the 260 knobby capsomeres located at all the local and strict threefold axes and the aqueous channels located at all the five- and six-coordinated positions. These protrusions extend outward from an inner radius of 28 nm. They are interconnected out to a radius of 30 nm by saddle-shaped densities across the local and strict twofold axes. The aqueous channels surrounded by these capsomeres are about 8 nm wide at the outer surface and 8 nm deep. Some of these channels extend inward, penetrating the inner layer. These channels may provide pathways for transporting the metabolites and mRNA during the transcriptase activity of the particles. The inner layer is a featureless smooth bed of density except for the indentations in register with the channels of the outer layer. We propose that the 260 capsomeres in the outer layer are made up of trimers of the major protein, VP7, and that the inner layer is composed of the second major protein, VP3. The density in the central portion of the structure at a radius of less than 21 nm is likely due to the minor proteins and the genomic RNA. Images PMID:1312624

Prasad, B V; Yamaguchi, S; Roy, P

1992-01-01

248

Photopolarimetry team outer planets mission definition phase  

NASA Technical Reports Server (NTRS)

The work is reported of the Photopolarimetry Team in identifying scientific objectives for photometer/polarimeter experiments for outer planet flyby missions. A discussion of the scientific objectives which can be attained with a photometer/polarimeter experiment, and summaries of the special studies which were performed for the Photopolarimetry Team are presented along with a description of the photometer/polarimeter design which was developed for the Meteoroid Detection Team.

1972-01-01

249

Wave observations in outer planet magnetospheres  

Microsoft Academic Search

The first measurements of plasma waves and wave-particle interactions in the magnetospheres of the outer planets were provided\\u000a by instruments on Voyager 1 and 2. At Jupiter, the observations yielded new information on upstream electrons and ions, bow\\u000a shock dissipation processes, trapped radio waves in the magnetospheres and extended Jovian magnetotail, pitch angle diffusion\\u000a mechanisms and whistlers from atmospheric lightning.

Frederick L. Scarf; Redondo Beach

1985-01-01

250

A model environment for outer zone electrons  

NASA Technical Reports Server (NTRS)

A brief morphology of outer zone electrons is given to illustrate the nature of the phenomena that we are attempting to model. This is followed by a discussion of the data processing that was done with the various data received from the experimenters before incorporating it into the data base from which this model was ultimately derived. The details of the derivation are given, and several comparisons of the final model with the various experimental measurements are presented.

Singley, G. W.; Vette, J. I.

1972-01-01

251

New fatty acids from outer space  

Microsoft Academic Search

A recent space exploration has revealed that in the far reaches of outer space matter attains a state of complete weightlessness.\\u000a Herman Brown, reporting on his latest spaced-out venture, indicates that weightless fatty acids obtained from the Superba\\u000a Galaxy are ideally suited for the manufacture of improved food additives. What a magnificent way to provide the diet-control\\u000a foodstuffs of the

H. Brown

1979-01-01

252

Planetary magnetism in the outer solar system.  

NASA Technical Reports Server (NTRS)

A brief review of the salient considerations which apply to the existence of magnetic fields in connection with planetary and subplanetary objects in the outer solar system is given. Consideration is given to internal dynamo fields, fields which might originate from interaction with the solar wind or magnetospheres (externally driven dynamos) and lastly fossil magnetic fields such as have been discovered on the moon. Where possible, connection is made between magnetism, means of detection, and internal body properties.

Sonett, C. P.

1973-01-01

253

Fluxgate magnetometers for outer planets exploration  

NASA Technical Reports Server (NTRS)

The exploration of the interplanetary medium and the magnetospheres of the outer planets requires the implementation of magnetic field measuring instrumentation with wide dynamic range, high stability, and reliability. The fluxgate magnetometers developed for the Pioneer 11 and Mariner-Jupiter-Saturn missions are presented. These instruments cover the range of .01 nT to 2 million nT with optimum performance characteristics and low power consumption.

Acuna, M. H.

1974-01-01

254

Analysis of the micropipet experiment with the anisotropic outer hair cell wall.  

PubMed

The in-plane and bending stiffnesses of the outer hair cell wall are characteristics crucial to the understanding of force and energy transmission between cochlear elements. A mathematical interpretation is given of the micropipet experiment directed at determining the outer hair cell wall stiffness. On the basis of the microstructural observation of the wall showing that it comprises protein networks with different elastic properties, the model of an orthotropic cylindrical shell is used. The boundary-value problem is analyzed corresponding to the stress-strain of the wall (shell) caused by the action of the micropipet. The solution is given in terms of Fourier series with respect to the circumferential coordinate. An asymptotic analysis of the solution is developed and an approximate formula for the length of the tongue aspirated within the pipet is derived. This leads to an analytical expression for the stiffness parameter measured in the micropipet experiment in terms of Young's moduli and Poisson's ratios of the wall. This expression is an important part of the estimation of the elastic constants of the wall. PMID:9479753

Spector, A A; Brownell, W E; Popel, A S

1998-02-01

255

CLOSURE WELD DEVELOPMENT FOR 3013 OUTER CONTAINERS  

SciTech Connect

Excess plutonium materials in the DOE complex are packaged and stored in accordance with DOE-STD-3013. This standard specifies requirements for the stabilization of such materials and subsequent packaging in dual nested seal-welded containers. Austenitic stainless steels have been selected for container fabrication. The inner 3013 container provides contamination control while the outer 3013 container is the primary containment vessel and is the focus of this paper. Each packaging site chose a process for seal welding the outer 3013 containers in accordance with its needs and expertise. The two processes chosen for weld closure were laser beam welding (LBW) and gas tungsten arc welding (GTAW). Following development efforts, each system was qualified in accordance with DOE-STD-3013 prior to production use. The 3013 outer container closure weld joint was designed to accommodate the characteristics of a laser weld. This aspect of the joint design necessitated some innovative process and equipment considerations in the application of the GTAW process. Details of the weld requirements and the development processes are presented and several potential enhancements for the GTAW system are described.

Daugherty, W.; Howard, S.; Peterson, K.; Stokes, M.

2009-11-10

256

Radio wave scattering in the outer heliosphere  

NASA Technical Reports Server (NTRS)

Current models for the 2-3 kHz emissions observed by the Voyager spacecraft in the outer heliosphere involve 2f(p) radiation generated near the termination shock or the heliopause. Radio wave scattering by solar wind density irregularities strongly affects observed sources of f(p) and 2f(p) emission in the inner heliosphere and the characteristics of astrophysical sources. In particular, the angular size, brightness temperature, and time variability of the source are strongly affected by scattering, thereby having major implications for the inferred size, energy budget, time variability, location, and nature of the source if scattering is ignored. This paper addresses whether scattering is important for interpreting the Voyager 2-3 kHz emissions. Quantitative calculations (with and without diffraction) are performed for the angular broadening of an outer heliospheric source as a function of path length, radiation frequency relative to f(p) and the spectrum of density irregularities. The effects of scattering in both the solar wind and the heliosheath are considered. Predictions for radial gradients in the source's apparent angular size and in the source's modulation index are presented. The calculations are compared with observations and the results discussed. First estimates suggest that scattering plausibly dominates the observed source size. The observed trend in modulation index with heliocentric distance is consistent with scattering being important and the source being in the outer heliosphere. Additional arguments for scattering being important are summarized.

Cairns, Iver H.

1995-01-01

257

Measuring Outer Disk Warps with Optical Spectroscopy  

E-print Network

Warps in the outer gaseous disks of galaxies are a ubiquitous phenomenon, but it is unclear what generates them. One theory is that warps are generated internally through spontaneous bending instabilities. Other theories suggest that they result from the interaction of the outer disk with accreting extragalactic material. In this case, we expect to find cases where the circular velocity of the warp gas is poorly correlated with the rotational velocity of the galaxy disk at the same radius. Optical spectroscopy presents itself as an interesting alternative to 21-cm observations for testing this prediction, because (i) separating the kinematics of the warp from those of the disk requires a spatial resolution that is higher than what is achieved at 21 cm at low HI column density; (ii) optical spectroscopy also provides important information on star formation rates, gas excitation, and chemical abundances, which provide clues to the origin of the gas in warps. We present here preliminary results of a study of the kinematics of gas in the outer-disk warps of seven edge-on galaxies, using multi-hour VLT/FORS2 spectroscopy.

Daniel Christlein; Joss Bland-Hawthorn

2008-08-28

258

Controllable fabrication and magnetic properties of double-shell cobalt oxides hollow particles  

PubMed Central

Double-shell cobalt monoxide (CoO) hollow particles were successfully synthesized by a facile and effective one-pot solution-based synthetic route. The inner architecture and outer structure of the double-shell CoO hollow particles could be readily created through controlling experimental parameters. A possible formation mechanism was proposed based on the experimental results. The current synthetic strategy has good prospects for the future production of other transition-metal oxides particles with hollow interior. Furthermore, double-shell cobalt oxide (Co3O4) hollow particles could also be obtained through calcinating corresponding CoO hollow particles. The magnetic measurements revealed double-shell CoO and Co3O4 hollow particles exhibit ferromagnetic and antiferromagnetic behaviour, respectively. PMID:25736824

Zhang, Dan; Zhu, Jianyu; Zhang, Ning; Liu, Tao; Chen, Limiao; Liu, Xiaohe; Ma, Renzhi; Zhang, Haitao; Qiu, Guanzhou

2015-01-01

259

Controllable fabrication and magnetic properties of double-shell cobalt oxides hollow particles.  

PubMed

Double-shell cobalt monoxide (CoO) hollow particles were successfully synthesized by a facile and effective one-pot solution-based synthetic route. The inner architecture and outer structure of the double-shell CoO hollow particles could be readily created through controlling experimental parameters. A possible formation mechanism was proposed based on the experimental results. The current synthetic strategy has good prospects for the future production of other transition-metal oxides particles with hollow interior. Furthermore, double-shell cobalt oxide (Co3O4) hollow particles could also be obtained through calcinating corresponding CoO hollow particles. The magnetic measurements revealed double-shell CoO and Co3O4 hollow particles exhibit ferromagnetic and antiferromagnetic behaviour, respectively. PMID:25736824

Zhang, Dan; Zhu, Jianyu; Zhang, Ning; Liu, Tao; Chen, Limiao; Liu, Xiaohe; Ma, Renzhi; Zhang, Haitao; Qiu, Guanzhou

2015-01-01

260

Controllable fabrication and magnetic properties of double-shell cobalt oxides hollow particles  

NASA Astrophysics Data System (ADS)

Double-shell cobalt monoxide (CoO) hollow particles were successfully synthesized by a facile and effective one-pot solution-based synthetic route. The inner architecture and outer structure of the double-shell CoO hollow particles could be readily created through controlling experimental parameters. A possible formation mechanism was proposed based on the experimental results. The current synthetic strategy has good prospects for the future production of other transition-metal oxides particles with hollow interior. Furthermore, double-shell cobalt oxide (Co3O4) hollow particles could also be obtained through calcinating corresponding CoO hollow particles. The magnetic measurements revealed double-shell CoO and Co3O4 hollow particles exhibit ferromagnetic and antiferromagnetic behaviour, respectively.

Zhang, Dan; Zhu, Jianyu; Zhang, Ning; Liu, Tao; Chen, Limiao; Liu, Xiaohe; Ma, Renzhi; Zhang, Haitao; Qiu, Guanzhou

2015-03-01

261

Fabrication of bifunctional core-shell Fe3O4 particles coated with ultrathin phosphor layer  

PubMed Central

Bifunctional monodispersed Fe3O4 particles coated with an ultrathin Y2O3:Tb3+ shell layer were fabricated using a facile urea-based homogeneous precipitation method. The obtained composite particles were characterized by powder X-ray diffraction, transmission electron microscopy (TEM), quantum design vibrating sample magnetometry, and photoluminescence (PL) spectroscopy. TEM revealed uniform spherical core-shell-structured composites ranging in size from 306 to 330 nm with a shell thickness of approximately 25 nm. PL spectroscopy confirmed that the synthesized composites displayed a strong eye-visible green light emission. Magnetic measurements indicated that the composite particles obtained also exhibited strong superparamagnetic behavior at room temperature. Therefore, the inner Fe3O4 core and outer Y2O3:Tb3+ shell layer endow the composites with both robust magnetic properties and strong eye-visible luminescent properties. These composite materials have potential use in magnetic targeting and bioseparation, simultaneously coupled with luminescent imaging. PMID:23962025

2013-01-01

262

Rhodamine functionalized magnetic core-shell nanocomposite: An emission 'Off-On' sensing system for mercury ion detection and extraction  

NASA Astrophysics Data System (ADS)

This paper reported a core-shell structured composite with superparamagnetic ferroferric oxide as the inner core and silica molecular sieve as the outer shell. A rhodamine based sensing dye was covalently grafted into the highly ordered tunnels of silica molecular sieve, so that mercury ion sensing and extraction could be achieved from this composite. This probe loaded core-shell structure was characterized by electron microscopy images, X-ray diffraction patterns, infrared spectra, thermogravimetry and N2 adsorption/desorption measurement. This composite showed increased emission with increasing mercury ion concentration, along with high sensitivity and good selectivity. Linear response and good regenerating performance were also observed from this composite.

Shen, Lei; Wu, Yan; Ma, Wuze

2015-03-01

263

Shell Creek Summers  

NSDL National Science Digital Library

What would motivate high school students to donate valuable summer vacation time to do science research?--the opportunity to make a difference! The Shell Creek Watershed Improvement Group (SCWIG) was formed to identify and promote needed conservation practices within a local watershed, and turned to the high school science department to help educate the public on water quality in the watershed and to establish a monitoring system that would be used to improve surface and groundwater quality. Since 2002, for the past three summers, in this ongoing project, students collect water quality data and report their findings to the three involved community organizations.

Mark Seier

2005-04-01

264

Hard (State) Problems  

E-print Network

For microquasars, the one time when these systems exhibit steady and powerful jets is when they are in the hard state. Thus, our understanding of this state is key to learning about the disk/jet connection. Recent observational and theoretical results have led to questions about whether we really understand the physical properties of this state, and even our basic picture of this state is uncertain. Here, I discuss some of the recent developments and possible problems with our understanding of this state. Overall, it appears that the strongest challenge to the standard truncated disk picture is the detection of broad iron features in the X-ray spectra, and it seems that either there is a problem with the truncated disk picture or there is a problem with the relativistic reflection models used to explain the broad iron features.

John A. Tomsick

2008-12-16

265

Exciting Hard Spheres  

E-print Network

We investigate the collision cascade that is generated by a single moving incident particle on a static hard-sphere gas. We argue that the number of moving particles at time t grows as t^{xi} and the number collisions up to time t grows as t^{eta}, with xi=2d/(d+2) and eta=2(d+1)/(d+2) and d the spatial dimension. These growth laws are the same as those from a hydrodynamic theory for the shock wave emanating from an explosion. Our predictions are verified by molecular dynamics simulations in d=1 and 2. For a particle incident on a static gas in a half-space, the resulting backsplatter ultimately contains almost all the initial energy.

T. Antal; P. L. Krapivsky; S. Redner

2008-05-25

266

Shoulder and hip joints for hard space suits and the like  

NASA Technical Reports Server (NTRS)

For use in hard space suits and the like, a joint between the torso covering and the upper arm covering (i.e., shoulder) or between the torso covering and upper leg covering (i.e., hip) is disclosed. Each joint has an outer covering and a inner covering. The outer covering has plural perferably truncated toroidal sections decreasing in size proceeding outwardly. In one embodiment at each joint there are two bearings, the first larger than the second. The outer race of the larger bearing is attached to the outer edge of the smaller end of each section and the inner race of the larger bearing is attached to the end wall. The inner race of the smaller bearing is attached to the end wall. The outer race of the smaller bearing is attached to the larger end of the next section. Each bearing hask appropriate seals. Between each section is a rubber ring for the comfort of the wearer. Such rubber rings have radial flanges attached to the inner races of two adjacent bearings. Matching semicircular grooves are formed in the abutting overlapping surfaces. Bellows-like inner walls are also provided for each section fixed at one end to an inner cylindrical flange and, at the opposite end, to an end wall. Each outer section may rotate 360 deg relative to the next outer section, whereas the bellows sections do not rotate, but rather expand or contract locally as the rigid sections rotate relative to each other.

Vykukal, H. C.

1986-01-01

267

The structure of circumstellar shells  

NASA Technical Reports Server (NTRS)

This document provides a report on research activities carried out with the support of NASA grant NAG 5-1174, the Structure of Circumstellar Shells, funded under the Astrophysics Data Program. The research carried out with the support of this grant is a study of the properties of circumstellar dust shells for which spectra are available through IRAS low resolution spectrometry (LRS). This research consisted of the development and application of models of axisymmetric circumstellar shells and a preliminary survey of the applicability of neural nets for analysis of the IRAS LRS spectra of circumstellar dust shells.

Fix, John D.

1993-01-01

268

April 21, 2010 XMM-Newton and SUZAKU detection of an X-ray emitting shell  

E-print Network

by a hard spectrum, which can be modeled either with a power-law ( = 2.9) or with a thermal plasma model (kT of the shell and PWN shock. Key words. ISM: supernova remnants ­ (ISM:) dust, extinction, X-rays ­ ISM, X

269

Estimation of elastic moduli and bending stiffness of the anisotropic outer hair cell wall.  

PubMed

The outer hair cell makes both passive and active contributions to basilar membrane mechanics. The outer hair cell mechanics is strongly coupled to the elastic properties of the cell lateral wall. The lateral wall experiences both in-plane deformations and bending under physiological and experimental conditions. To characterize the outer hair cell wall, the model of an orthotropic cylindrical shell is used. The elastic constants of the wall are estimated by solving a set of three equations based on the analyses of three independent experiments. The first equation is derived from a new interpretation of the micropipet experiment; the other two are obtained from the axial loading and the osmotic challenge experiments. The two Young's moduli corresponding to the longitudinal and circumferential directions and two Poisson's ratios are estimated. The longitudinal, circumferential, and mixed modes of the bending stiffness are also estimated. The sensitivity of the derived constants to the variation of the cell axial stiffness, which has been measured by several independent groups, is examined. The new estimates are also compared with results obtained by using the assumption of the wall isotropy. PMID:9479754

Spector, A A; Brownell, W E; Popel, A S

1998-02-01

270

33 CFR 117.323 - Outer Clam Bay  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Outer Clam Bay 117.323 Section 117.323 Navigation...Specific Requirements Florida § 117.323 Outer Clam Bay The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on...

2010-07-01

271

Enzymatic properties and cholesterol content of mitochondrial outer mem-  

E-print Network

Enzymatic properties and cholesterol content of mitochondrial outer mem- branes in liver of obese and microsomes. Simultaneously microsomes were shown to be richer in cholesterol than mitochondrial outer, it was determined that outer membranes are extremely poor in cholesterol, far richer in to- tal fatty acids than

Boyer, Edmond

272

Scientific Goals for Exploration of the Outer Solar System  

E-print Network

Scientific Goals for Exploration of the Outer Solar System Explore Diverse Worlds How did the outer planets mold the solar system and create habitable worlds? OPAG Report DRAFT 4 November 2014 #12;2 Outline of this document is to frame the science objectives for exploration of the outer solar system. It is consistent

Rathbun, Julie A.

273

The bacterial outer membrane b-barrel assembly machinery  

E-print Network

REVIEW The bacterial outer membrane b-barrel assembly machinery Kelly H. Kim, Suraaj Aulakh. The b-barrel assembly machinery (BAM) complex, which is responsible for the proper assembly of b of the bacterial BAM complex. Keywords: outer membrane proteins; b-barrel assembly machinery; outer membrane

Paetzel, Mark

274

33 CFR 117.323 - Outer Clam Bay  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Outer Clam Bay 117.323 Section 117.323 Navigation...Specific Requirements Florida § 117.323 Outer Clam Bay The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on...

2011-07-01

275

33 CFR 117.323 - Outer Clam Bay  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Outer Clam Bay 117.323 Section 117.323 Navigation...Specific Requirements Florida § 117.323 Outer Clam Bay The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on...

2012-07-01

276

33 CFR 117.323 - Outer Clam Bay.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Outer Clam Bay. 117.323 Section 117.323 Navigation...Specific Requirements Florida § 117.323 Outer Clam Bay. The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on...

2013-07-01

277

33 CFR 117.323 - Outer Clam Bay.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Outer Clam Bay. 117.323 Section 117.323 Navigation...Specific Requirements Florida § 117.323 Outer Clam Bay. The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on...

2014-07-01

278

Automated shell theory for rotating structures (ASTROS)  

NASA Technical Reports Server (NTRS)

A computer program for analyzing axisymmetric shells with inertial forces caused by rotation about the shell axis is developed by revising the STARS II shell program. The basic capabilities of the STARS II shell program, such as the treatment of the branched shells, stiffened wall construction, and thermal gradients, are retained.

Foster, B. J.; Thomas, J. M.

1971-01-01

279

Project EARTH-12-SHELL4: Shell Geoscience Laboratory  

E-print Network

Project EARTH-12-SHELL4: Shell Geoscience Laboratory Polygonal faults and de-watering of mudrocks (subject to contract) Polygonal faults are widely regarded as a response to dewatering during the earliest it is generally agreed that polygonal fault genesis is related to dewatering during the first few hundred metres

Henderson, Gideon

280

Biomineralisation in Mollusc shells  

NASA Astrophysics Data System (ADS)

The main components of Mollusc shells are carbonate minerals: calcite and aragonite. ACC is present in larval stages. Calcite and aragonite can be secreted simultaneously by the mantle. Despite the small number of varieties, the arrangement of the mineral components is diverse, and dependant upon the taxonomy. They are also associated with organic components much more diverse, the diversity of which reflects the large taxonomic diversity. From TGA analyses, the organic content (water included) is high (>5% in some layers). The biomineralisation process is not a passive precipitation process, but is strongly controlled by the organism. The biological-genetic control is shown by the constancy of the arrangement of the layers, the mineralogy and the microstructure in a given species. Microstructural units (i.e. tablets, prisms etc.) have shapes that do not occur in non-biogenic counterparts. Nacreous tablets, for example, are flattened on their crystallographic c axis, which is normally the axis of maximum growth rate for non-biogenic aragonite. Morever, their inner structure is species-specific: the arrangements of nacreous tablets in Gastropoda - Cephalopoda, and in Bivalvia differ, and the inner arrangement of the nacreous tablets is different in ectocochlear and endocochlear Cephalopoda. The organic-mineral ratios also differ in the various layers of a shell. Differences in chemical composition also demonstrates the biological-genetic control: for example, aragonite has a low Sr content unknown in non-biogenic samples; two aragonitic layers in a shell have different Sr and Mg contents, S is higher in calcitic layers. Decalcification releases soluble (SOM) and insoluble (IOM) organic components. Insoluble components form the main part of the intercrystalline membranes, and contain proteins, polysaccharides and lipids. Soluble phases are present within the crystals and the intercrystalline membranes. These phases are composed of more or less glycosylated proteins and polysaccharides, with a large range of molecular weights. Proteins are rich in acidic aminoacids (aspartic and glutamic acids). Sugars are usually sulphated, and very acidic. Several hundreds of proteins and sugars are present in the SOM. The compositions of IOM and SOM are characteristic for each layer present in a shell. Topographical relationships of mineral and organic components are visible at different scales of observation. SEM images of etched surfaces display the growth line rhythmicity and concordance between adjacent microstructural units. EPMA maps show similar chemical growth lines in various structures. Whatever the taxa, the average thickness of growth lines is about 2-3 µm, indicating an inner biological rhythm, not dependant on the environmental conditions. Such growth lines are observed in deep sea molluscs at depth where diurnal changes in light and temperature are absent. However, the role of the environment is shown by larger periodicities. Sulphur deserves a special interest, because it is associated with the organic matrices. Electrophoretic data have shown that acidic sulphated sugars are abundant in some layers. XANES analyses confirm these results. New microscopic techniques allow us to obtain images at a submicrometer scale. AFM images show that all the microstructural units (i.e. tablets, prisms etc.), calcite or aragonite, are composed of small sub-spherical granules with a diameter typically of about 50 nm. These granules are surrounded by a thin cortex (about 8 nm) of organic and/or amorphous material, and are organo-composite material as shown by phase images. They do not have crystalline shapes, despite the fact that the units they build are often monocrystalline. Molecular biology and genetic studies confirm that the control of the biomineralisation process is exerted at the scale of the whole organism: the expression of genes encoding major shell matrix proteins clearly indicates a regular separation of calcite and aragonite secretory activity. The main control on the structural and compositional features of mollusc she

Dauphin, Y.; Cuif, J. P.; Salomé, M.; Williams, C. T.

2009-04-01

281

Hi shells, supershells, shell-like objects, and ''worms''  

SciTech Connect

We present photographic representations of the combination of two Hi surveys, so as to eliminate the survey boundaries at Vertical BarbVertical Bar = 10/sup 0/. We also present high-contrast photographs for particular velocities to exhibit weak Hi features. All of these photographs were used to prepare a new list of Hi shells, supershells, and shell-like objects. We discuss the structure of three shell-like objects that are associated with high-velocity gas, and with gas at all velocities that is associated with radio continuum loops I, II, and III. We use spatial filtering to find wiggly gas filaments: ''worms'': crawling away from the galactic plane in the inner Galaxy. The ''worms'' are probably parts of shells that are open at the top; such shells should be good sources of hot gas for the galactic halo.

Heiles, C.

1984-08-01

282

Versatile post-functionalization of the external shell of cowpea chlorotic mottle virus by using click chemistry.  

PubMed

We present the modification of the outer protein shell of cowpea chlorotic mottle virus (CCMV) with linear and strained alkyne groups. These functionalized protein capsids constitute valuable platforms for post-functionalization via click chemistry. After modification, the integrity of the capsid and the reversible disassembly behavior are preserved. PMID:24817149

Hommersom, C A; Matt, B; van der Ham, A; Cornelissen, J J L M; Katsonis, N

2014-06-28

283

Lunar and Planetary Science XXXV: Outer Solar System  

NASA Technical Reports Server (NTRS)

The session 'Outer Solar System" inlcuded:Monte Carlo Modeling of [O I] 630 nm Auroral Emission on Io; The Detection of Iron Sulfide on Io; Io and Loki in 2003 as Seen from the Infrared Telescope Facility Using Mutual Satellite and Jupiter Occultations; Mapping of the Zamama-Thor Region of Io; First Solar System Results of the Spitzer Space Telescope; Mapping the Surface of Pluto with the Hubble Space Telescope; Experimental Study on Fischer-Tropsch Catalysis in the Circum-Saturnian Subnebula; New High-Pressure Phases of Ammonia Dihydrate; Gas Hydrate Stability at Low Temperatures and High Pressures with Applications to Mars and Europa; Laboratory UV Photolysis of Planetary Ice Analogs Containing H2O + CO2 (1:1); The OH Stretch Infrared Band of Water Ice and Its Temperature and Radiation Dependence; Band Position Variations in Reflectance Spectra of the Jovian Satellite Ganymede; Comparison of Porosity and Radar Models for Europa s Near Surface; Combined Effects of Diurnal and Nonsynchronous Surface Stresses on Europa; Europa s Northern Trailing Hemisphere: Lineament Stratigraphic Framework; Europa at the Highest Resolution: Implications for Surface Processes and Landing Sites; Comparison of Methods to Determine Furrow System Centers on Ganymede and Callisto; Resurfacing of Ganymede by Liquid-Water Volcanism; Layered Ejecta Craters on Ganymede: Comparisons with Martian Analogs; Evaluation of the Possible Presence of CO2-Clathrates in Europa s Icy Shell or Seafloor; Geosciences at Jupiter s Icy Moons: The Midas Touch; Planetary Remote Sensing Science Enabled by MIDAS (Multiple Instrument Distributed Aperture Sensor); and In Situ Surveying of Saturn s Rings.

2004-01-01

284

Methane Group Ions in Saturn's Outer Magnetosphere  

NASA Astrophysics Data System (ADS)

In Hartle et al. [2006a,b] they reported evidence of keV methane group ions within Saturn's outer magnetosphere during Cassini's TA Titan flyby. They presented evidence of CH4+ pickup ions within the mass loading region of the magnetospheric interaction with Titan. They also reported that keV water group ions W+ (i.e., O+) were present and dominated the magnetospheric heavy ion composition. These water group ions probably result from the emission of fast neutrals from the Enceladus torus via charge exchange reactions but still gravitationally bound to Saturn [see Johnson et al., 2005 and Sittler et al. 2006] and then become ionized in the outer magnetosphere where the pickup energies are keV. Since O+ and CH4+ have similar mass the primary discriminator is the O- fragment which appears at a different time-of-flight (TOF) than that for mass 16. One way to separate the methane from the O+ is to measure the relative abundance of the mass 16 peak with the O- peak. If there is a methane torus as a consequence of the hydrodynamic model of Strobel [2008], then one expects the presence of CH3+ ions and not CH4+ ions, since the methane dissociates to CH3 before they get ionized. Here we will be reporting on a further search for evidence of methane group ions within Saturn's outer magnetosphere. References: Hartle, R. E., et al., Geophys. Res. Lett., 33, L08201, 2006a Hartle, R. E., et al., Planet. Space Sci., 54, 1211, 2006b Johnson. R.E., et. Astrophys. J. Letts, 644, L137-L139, 2005 Sittler, E. C., Jr., et al., JGR, 111, A09223, 2006 Strobel, D. F., Icarus, 193, 588, [2008

Sittler, Edward C.; Hartle, R. E.; Cooper, J. F.; Johnson, R. E.; Smith, H. T.; Shappirio, M. D.; Simpson, D. J.

2008-09-01

285

Biomechanics of turtle shells: how whole shells fail in compression.  

PubMed

Turtle shells are a form of armor that provides varying degrees of protection against predation. Although this function of the shell as armor is widely appreciated, the mechanical limits of protection and the modes of failure when subjected to breaking stresses have not been well explored. We studied the mechanical properties of whole shells and of isolated bony tissues and sutures in four species of turtles (Trachemys scripta, Malaclemys terrapin, Chrysemys picta, and Terrapene carolina) using a combination of structural and mechanical tests. Structural properties were evaluated by subjecting whole shells to compressive and point loads in order to quantify maximum load, work to failure, and relative shell deformations. The mechanical properties of bone and sutures from the plastral region of the shell were evaluated using three-point bending experiments. Analysis of whole shell structural properties suggests that small shells undergo relatively greater deformations before failure than do large shells and similar amounts of energy are required to induce failure under both point and compressive loads. Location of failures occurred far more often at sulci than at sutures (representing the margins of the epidermal scutes and the underlying bones, respectively), suggesting that the small grooves in the bone created by the sulci introduce zones of weakness in the shell. Values for bending strength, ultimate bending strain, Young's modulus, and energy absorption, calculated from the three-point bending data, indicate that sutures are relatively weaker than the surrounding bone, but are able to absorb similar amounts of energy due to higher ultimate strain values. PMID:23203474

Magwene, Paul M; Socha, John J

2013-02-01

286

Dishwasher For Earth Or Outer Space  

NASA Technical Reports Server (NTRS)

Dishwashing machine cleans eating utensils in either Earth gravity or zero gravity of outer space. Cycle consists of three phases: filling, washing, and draining. Rotation of tub creates artificial gravity aiding recirculation of water during washing phase in absence of true gravity. Centrifugal air/water separator helps system function in zero gravity. Self-cleaning filter contains interdigitating blades catching solid debris when water flows between them. Later, blades moved back and forth in scissor-like manner to dislodge debris, removed by backflow of water.

Tromble, Jon D.

1991-01-01

287

Overview of 2008 Outer Planet Flagship Studies  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the process involved in the Phase-2 studies for the next Outer Planets Flagship (OPF). These studies will be a cooperative effort with ESA and JAXA in partnership with NASA. The annoucement of oppurtunity (AO) for the science instruments and the launch approval/planetary protection processes are reviewed. There is also discussion about capturing relevant lessons from the Cassini team, supporting international collaboration, and support for science definition teams. Some mission specific tasks are also reviewed, for the three missions being proposed: (1) Europa Explorer, (2) Jupiter System Observer and (3) Titan Explorer. A timeline for the studies is also included.

Reh, Kim R.

2008-01-01

288

Outer atmospheres of giant and supergiant stars  

NASA Technical Reports Server (NTRS)

The properties of the chromospheres, transition regions and coronas of cool evolved stars are reviewed based primarily on recent ultraviolet and X-ray studies. Determinations of mass loss rates using new observational techniques in the ultraviolet and radio spectral regions are discussed and observations indicating general atmospheric motions are considered. The techniques available for the quantitative modeling of these atmospheres are outlined and recent results discussed. Finally, the current rudimentary understanding of the evolution of these outer atmospheres and its causes are considered.

Brown, A.

1984-01-01

289

Aging phenomena in the LHCb outer tracker  

E-print Network

The Outer Tracker (OT) consists of 53 760 straw tubes, covering in total an area of 360 m$^2$. The detector is foreseen to operate under large particle rates, up to 30 kHz/cm per straw in the region closest to the beam. Extensive aging tests conducted earlier on with prototype modules indicated excellent gain stability. In contrast, mass production modules show significant degradation under a rather model level of radiation. This paper presents the observed phenomenon, together with ongoing investigations to both prevent the effect, as well as to recover the gain loss.

Haas, Tanja

2007-01-01

290

Dark matter in the outer solar system  

NASA Technical Reports Server (NTRS)

There are now a large number of small bodies in the outer solar system that are known to be covered with dark material. Attempts to identify that material have been thwarted by the absence of discrete absorption features in the reflection spectra of these planetesimals. An absorption at 2.2 micrometers that appeared to be present in several objects has not been confirmed by new observations. Three absorptions in the spectrum of the unusually red planetesimal 5145 Pholus are well-established, but their identity remains a mystery.

Owen, T.; Cruikshank, D.; De Bergh, C.; Geballe, T.

1994-01-01

291

Shell forming system  

NASA Technical Reports Server (NTRS)

An apparatus is provided for forming gas-filled spheres of metal, glass or other material, which produces spheres (12) of uniform size and wall thickness in a relatively simple system. The system includes concentric nozzles, including an inner nozzle (18) through which gas flows and and an outer nozzle (20), which jointly define an annular passageway (50) through which a liquid flows. The flow rates are adjusted so that the gas flows at greater velocity than does the liquid, out of their respective nozzles, e.g. three times as great, in order to produce an extrusion (30) which undergoes axisymmetric oscillations resulting in the pinch off into hollow spheres with very uniform spacing. The system is useful not only where gas-filled spheres are required, but also is useful to accurately control the dispensing of solid, liquid, or gaseous materials.

Kendall, Jr., James M. (Inventor); Wang, Taylor G. (Inventor); Elleman, Daniel D. (Inventor)

1987-01-01

292

Measuring the Hardness of Minerals  

ERIC Educational Resources Information Center

The author discusses Moh's hardness scale, a comparative scale for minerals, whereby the softest mineral (talc) is placed at 1 and the hardest mineral (diamond) is placed at 10, with all other minerals ordered in between, according to their hardness. Development history of the scale is outlined, as well as a description of how the scale is used…

Bushby, Jessica

2005-01-01

293

Instability localized at the inner surface of an imploding spherical shell  

SciTech Connect

It is shown that in an imploding spherical shell the surface instabilities are of two different types. The first, which occurs at the outer surfaces, is the Rayleigh-Taylor instability. The second instability occurs at the inner surface. This latter instability is not as disruptive as R-T modes, but it has three basic properties which differ considerably from those of the R-T instability: (1) it is oscillatory at early times; (2) it grows faster in the long wavelength modes; (3) it depends on the equation of state. It is further shown that this new instability is driven by amplified sound waves in the shell.

Han, S.J.

1983-01-01

294

Discovery of Molecular Gas Shells around the Unusual Galaxy Centaurus A  

NASA Astrophysics Data System (ADS)

Recent observations by an international team of astronomers [1] with the 15-metre Swedish-ESO Submillimetre Telescope at the La Silla observatory (Chile) have shown that the unusual, nearby galaxy Centaurus A is surrounded by shells in which carbon monoxide molecules are present. These new exciting results are the first of their kind. In addition to the intrinsic scientific value of this discovery, it also provides an instructive example of what will become possible for more distant galaxies with the projected Atacama Large Millimeter Array (ALMA) , now in the planning phase. Ellipticals and spirals Galaxies come in different shapes. Some of these take the form of more or less perfect spirals, some have the form of ellipsoids and still others have an irregular appearance. One of the major differences between elliptical and spiral galaxies is that the former do not possess extensive gaseous discs in which young stars can be formed. This is despite the fact that most elliptical galaxies are probably formed by the merger of two or more spiral galaxies. However, during such a process most of the gas in the spirals is either quickly turned into stars by massive bursts of star formation or is completely lost into the surrounding space. Shells around elliptical galaxies Most galaxies are members of groups. Once they have been formed, massive elliptical galaxies in these often behave like "cannibals" by swallowing one or more smaller companion galaxies. Some vestiges of such an event may remain visible for a certain time after the merger, normally in the form of weak structures in the otherwise smooth light distribution over the elliptical galaxy. These structures resemble the ripples or waves that develop on the water surface when you throw a small stone into a calm pond. While long-exposure photos show them as faint "rings" around the galaxy, they are in fact the projected images of three-dimensional structures and are often referred to as shells . By means of photometric and spectrographic studies of their light, it has been known since the early 1980's that such shells are made up of stars. It appears that they are quite common - about half of the nearby large elliptical galaxies have been found to be surrounded by stellar shells. More recently, in 1994, atomic hydrogen gas was discovered to be associated with some of the stellar shells. This discovery was a bit of a surprise, because the current theory predicts that when two galaxies merge, their gas and stars will behave very differently. While the individual stars hardly ever hit each other, the interstellar gas clouds collide violently. They will lose all their energy and the gas will fall towards the common centre where it is soon consumed in vigorous bursts of star formation. Why would there then be hydrogen gas in the outer shells of some elliptical galaxies? A possible origin of gaseous shells The astronomer team, headed by Vassilis Charmandaris [1] decided to look into this serious discrepancy between theory and observations. They believed that a possible explanation might be that this diffuse atomic gas is located, not in vast, very dilute clouds, but rather in smaller, much denser molecular clouds , such as these are known in our own galaxy, the Milky Way. Due to their relative compactness (more than 1000 molecules/cm 3 , i.e,. at least 100 times more than that of larger diffuse clouds), molecular clouds would behave more like the stars during the galaxy collision event. Indeed, realistic calculations showed that the dynamical behavior of such dense clouds would be intermediate between the stars and the diffuse hydrogen gas. Thus, while most of the gas would still end up in the centre of the remaining galaxy after a merger, a larger fraction of it would be able to survive at large distances from the nucleus. This would then be the origin of the observed hydrogen shells. During the merger, gas that originates from regions in the outskirts of the "cannibalized" galaxy - and farther out than most of the stars - would be liberated earlier

2000-03-01

295

Atmospheric entry probes for outer planet exploration. Outer planet entry probe technical summary  

NASA Technical Reports Server (NTRS)

The use of unmanned space probes for investigating the conditions existing on and around the outer planets of the solar system is discussed. The subjects included in the report are: (1) the design of a common entry probe for outer planet missions, (2) the significant trades related to the development of a common probe design, (3) the impact of bus selection on probe design, (4) the impact of probe requirements on bus modifications, and (5) the key technology elements recommended for advanced development. Drawings and illustrations of typical probes are included to show the components and systems used in the space probes.

1974-01-01

296

Deep Near-Infrared Imaging af an Embedded Cluster in the Extreme Outer Galaxy: Census of Supernovae Triggered Star Formation  

E-print Network

While conducting a near-infrared (NIR) survey of ``Digel Clouds'', which are thought to be located in the extreme outer Galaxy (EOG), Kobayashi & Tokunaga found star formation activity in ``Cloud 2'', a giant molecular cloud at the Galactic radius of ~ 20 kpc. Additional infrared imaging showed two embedded young clusters at the densest regions of the molecular cloud. Because the molecular cloud is located in the vicinity of a supernova remnant (SNR) HI shell, GSH 138-01-94, it was suggested that the star formation activity in Cloud 2 was triggered by this expanding HI shell. We obtained deep J (1.25 um), H (1.65 um) and K (2.2 um) images of one of the embedded clusters in Cloud 2 with high spatial resolution (FWHM ~0".3) and high sensitivity (K ~ 20 mag, 10 sigma). We identified 52 cluster members. The estimated stellar density (~ 10 pc^{-2}) suggests that the cluster is a T-association. This is the deepest NIR imaging of an embedded cluster in the EOG. The observed K-band luminosity function (KLF) suggests that the underlying initial mass function (IMF) of the cluster down to the detection limit of ~ 0.1 M_sun is not significantly different from the typical IMFs in the field and in the near-by star clusters. The overall characteristics of this cluster appears to be similar to those of other embedded clusters in the far outer Galaxy. The estimated age of the cluster from the KLF, which is less than 1 Myr, is consistent with the view that the star formation was triggered by the HI shell whose age was estimated at 4.3 Myr (Stil & Irwin). The 3-dimensional geometry of SNR shell, molecular cloud and the embedded cluster, which is inferred from our data, as well as the cluster age strongly suggest that the star formation in Cloud 2 was triggered by the SNR shell.

Chikako Yasui; Naoto Kobayashi; Alan T. Tokunaga; Hiroshi Terada; Masao Saito

2006-06-01

297

Manufacturing Complicated Shells And Liners  

NASA Technical Reports Server (NTRS)

Explosive forming, wax filling, and any one of welding, diffusion bonding, or brazing used in method of manufacturing large, complicated shell-and-liner vessels or structures. Method conceived for manufacture of film-cooled rocket nozzles but applicable to joining large coaxial shells and liners in general.

Sobol, Paul J.; Faucher, Joseph E.

1993-01-01

298

Shell Observations of Classical Novae  

NASA Astrophysics Data System (ADS)

We present shell observations of some classical novae from the Turkish National Observatory. We reobserved them to image their faint shells a long time after their outbursts. We revise the old findings with the new data and we call attention to narrow band pass observations.

Esenoglu, H. H.; Saygac, A. T.

2014-12-01

299

Tuna Sea Shell Pasta Ingredients  

E-print Network

Tuna Sea Shell Pasta Ingredients: 8 ounces pasta shells 12 ounces tuna in water, canned 1 onion 2. Cut the ends off of the onion, and peel off the brown layers. Run under water to remove any dirt. Cut the onion in half lengthwise, and place the flat side on the cutting board. Slice across the onion, from one

Liskiewicz, Maciej

300

Shell tile thermal protection system  

NASA Technical Reports Server (NTRS)

A reusable, externally applied thermal protection system for use on aerospace vehicles subject to high thermal and mechanical stresses utilizes a shell tile structure which effectively separates its primary functions as an insulator and load absorber. The tile consists of structurally strong upper and lower metallic shells manufactured from materials meeting the thermal and structural requirements incident to tile placement on the spacecraft. A lightweight, high temperature package of insulation is utilized in the upper shell while a lightweight, low temperature insulation is utilized in the lower shell. Assembly of the tile which is facilitated by a self-locking mechanism, may occur subsequent to installation of the lower shell on the spacecraft structural skin.

Macconochie, I. O.; Lawson, A. G.; Kelly, H. N. (inventors)

1984-01-01

301

Fluid-structure interaction during the impact of a cylindrical shell on a thin layer of water  

NASA Astrophysics Data System (ADS)

A two-dimensional unsteady analysis of an elastic circular cylindrical shell that enters a thin layer of an ideal incompressible liquid is considered. The cylinder initially touches the liquid free surface at a single point and then penetrates the liquid layer at a constant vertical velocity. The problem is coupled because the liquid flow, the shape of the elastic shell and the geometry of the contact region between the body and the liquid must be determined simultaneously. The flow region is subdivided into four complementary regions that exhibit different properties: the region beneath the entering body surface, the jet root, the spray jet, and the outer region. A complete solution is obtained by matching the solutions within these four subdomains. The structural analysis is based on the normal-mode method. Strain-time histories of the inner surface of the cylinder are of particular interest. In the case of a very flexible shell three distinct regimes of the impact process were found. For a high impact velocity the lower part of the shell flattens and the shell does not enter the water. For a moderate impact velocity the shell reaches the bottom and an effect of “fluid capture” may occur. For a low impact velocity the shell penetrates the liquid, but the size of the contact region decreases before the shell reaches the bottom. This behaviour corresponds to exit or “reflection” of the shell from the water layer.

Khabakhpasheva, T. I.

2009-04-01

302

OSSOS: The Outer Solar System Origins Survey  

NASA Astrophysics Data System (ADS)

We present the first detection set from the Outer Solar System Origins Survey (OSSOS) which is a mammoth 560-hour CFHT Large Program over 4 years (finishing January 2017). This is likely to be the largest Kuiper Belt survey before LSST comes on line (in terms of the number of precise transneptunian object (TNO) orbits it provides).OSSOS studies gradually-slewing 21-square degree blocks of sky that are repeatedly imaged in many dark runs over two semesters. This strategy is designed to detect and track TNOs in order to provide extremely high-quality orbits in a short amount of time; in 16-18 month arcs we are obtaining fractional semimajor axis uncertainties in the range 0.01-0.1% and accuracies in the libration amplitudes of resonant objects better than 10 degrees, due to mean astrometric residuals routinely being of order 50-100 milliarcseconds.This talk will present the survey design and full detection sample for objects observed in the first half of 2013 and 2014. We will report how adding these detections to those from the Canada-France Ecliptic Plane Survey (CFEPS) modifies conclusions about the orbital and size distribution of main classical Kuiper Belt, as well as other non-resonant sub-populations. In particular, because OSSOS is sensitive to, and has detected objects, from 8 AU to beyond 60 AU, we will report on how the combined distance and magnitude distribution impact dicsussions of the absolute magnitude distribution of outer Solar System objects.

Gladman, Brett; Bannister, Michele; Kavelaars, Jj; Petit, Jean-Marc; Gwyn, Stephen; Chen, Ying-Tung

2014-11-01

303

Hardness-based plasticity and fracture model for quench-hardenable boron steel (22MnB5)  

SciTech Connect

A comprehensive strain hardening and fracture characterization of different grades of boron steel blanks has been performed, providing the foundation for the implementation into the modular material model (MMM) framework developed by Volkswagen Group Research for an explicit crash code. Due to the introduction of hardness-based interpolation rules for the characterized main grades, the hardening and fracture behavior is solely described by the underlying Vickers hardness. In other words, knowledge of the hardness distribution within a hot-formed component is enough to set up the newly developed computational model. The hardness distribution can be easily introduced via an experimentally measured hardness curve or via hardness mapping from a corresponding hot-forming simulation. For industrial application using rather coarse and computationally inexpensive shell element meshes, the user material model has been extended by a necking/post-necking model with reduced mesh-dependency as an additional failure mode. The present paper mainly addresses the necking/post-necking model.

Greve, L., E-mail: lars.greve@volkswagen.de; Medricky, M., E-mail: miloslav.medricky@volkswagen.de; Andres, M., E-mail: miloslav.medricky@volkswagen.de [Volkswagen AG, Letter Box 1777, Wolfsburg, 38436 (Germany); Eller, T. K., E-mail: tom.karl.eller@volkswagen.de [Volkswagen AG, Letter Box 1777, Wolfsburg, 38436, Germany, and University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

2013-12-16

304

Beta Backscatter Measures the Hardness of Rubber  

NASA Technical Reports Server (NTRS)

Nondestructive testing method determines hardness, on Shore scale, of room-temperature-vulcanizing silicone rubber. Measures backscattered beta particles; backscattered radiation count directly proportional to Shore hardness. Test set calibrated with specimen, Shore hardness known from mechanical durometer test. Specimen of unknown hardness tested, and radiation count recorded. Count compared with known sample to find Shore hardness of unknown.

Morrissey, E. T.; Roje, F. N.

1986-01-01

305

Hardness Amplification Proofs Require Majority Ronen Shaltiel  

E-print Network

Hardness Amplification Proofs Require Majority Ronen Shaltiel Emanuele Viola April 28, 2010 Abstract Hardness amplification is the fundamental task of converting a -hard function f : {0, 1}n {0, 1} into a (1/2 - )-hard function Amp(f), where f is -hard if small circuits fail to compute f on at least

Viola, Emanuele

306

Design of multiple shell and tube heat exchangers in series: E shell and F shell  

Microsoft Academic Search

Multiple shell and tube heat exchangers in the series are employed to handle the temperature cross in the chemical process industries. Depending on the degree of temperature cross, certain number of heat exchangers (either E or F shell type) need to be connected in series such that the temperature cross in each exchanger is within allowable limit. Determination of the

U. Vengateson

2010-01-01

307

Isolation of the outer membrane and characterization of the major outer membrane protein from Spirochaeta aurantia.  

PubMed

The outer membrane of Spirochaeta aurantia was isolated after cells were extracted with sodium lauryl sarcosinate and was subsequently purified by differential centrifugation and KBr isopycnic gradient centrifugation. The purified outer membrane was obtained in the form of carotenoid-containing vesicles. Four protein species with apparent molecular weights of 26,000 (26K), 36.5K, 41K, and 48.5K were readily observed as components of the vesicles. The 36.5K protein was the major polypeptide and constituted approximately 90% of the outer membrane protein observed on sodium dodecyl sulfate-polyacrylamide gels. Under mild denaturing conditions the 36.5K major protein exhibited an apparent molecular weight of approximately 90,000. This, together with the results of protein cross-linking studies, indicates that the 36.5K polypeptide has an oligomeric conformation in the native state. Reconstitution of solubilized S. aurantia outer membrane into lipid bilayer membranes revealed the presence of a porin, presumably the 36.5K protein, with an estimated channel diameter of 2.3 nm based on the measured single channel conductance of 7.7 nS in 1 M KCl. PMID:3025168

Kropinski, A M; Parr, T R; Angus, B L; Hancock, R E; Ghiorse, W C; Greenberg, E P

1987-01-01

308

Core-shell-shell and hollow double-shell microgels with advanced temperature responsiveness.  

PubMed

Unique doubly temperature-responsive hollow microgels are presented. These consist of two concentric thermoresponsive polymer shells made of poly(N-isopropylacrylamide) (PNIPAM) and poly(N-isopropylmethacrylamide) (PNIPMAM), respectively. The hollow particles are derived from silica-PNIPAM-PNIPMAM core-shell-shell (CSS) particles by dissolution of the silica core. Light scattering measurements reveal the twofold volume phase transition behavior that occur in the PNIPAM and PNIPMAM regions of the CSS and the respective hollow particles. In the presence of the silica core, i.e., in case of the CSS particles, the swelling of the inner shell is tremendously restricted by the core. However, after the core is dissolved, the transition of the inner shell from the swollen to the collapsed state is highly pronounced. This versatile approach allows preparing hollow particles with individually tunable properties on the particle inside and outside for various applications as multifunctional smart materials. PMID:25354836

Dubbert, Janine; Nothdurft, Katja; Karg, Matthias; Richtering, Walter

2015-01-01

309

Oceans, Ice Shells, and Life on Europa  

NASA Technical Reports Server (NTRS)

The four large satellites of Jupiter are famous for their planet-like diversity and complexity, but none more so than ice-covered Europa. Since the provocative Voyager images of Europa in 1979, evidence has been mounting that a vast liquid water ocean may lurk beneath the moon's icy surface. Europa has since been the target of increasing and sometimes reckless speculation regarding the possibility that giant squid and other creatures may be swimming its purported cold, dark ocean. No wonder Europa tops everyone's list for future exploration in the outer solar system (after the very first reconnaissance of Pluto and the Kuiper belt, of course). Europa may be the smallest of the Galilean moons (so-called because they were discovered by Galileo Galilei in the early 17th century) but more than makes up for its diminutive size with a crazed, alien landscape. The surface is covered with ridges hundreds of meters high, domes tens of kilometers across, and large areas of broken and disrupted crust called chaos. Some of the geologic features seen on Europa resemble ice rafts floating in polar seas here on Earth-reinforcing the idea that an ice shell is floating over an ocean on this Moon-size satellite. However, such features do not prove that an ocean exists or ever did. Warm ice is unusually soft and will flow under its own weight. If the ice shell is thick enough, the warm bottom of the shell will flow, as do terrestrial glaciers. This could produce all the observed surface features on Europa through a variety of processes, the most important of which is convection. (Convection is the vertical overturn of a layer due to heating or density differences-think of porridge or sauce boiling on the stove.) Rising blobs from the base of the crust would then create the oval domes dotting Europa's surface. The strongest evidence for a hidden ocean beneath Europa's surface comes from the Galileo spacecraft's onboard magnetometer, which detected fluctuations in Jupiter's magnetic field consistent with a conductor inside Europa. The most likely conductor: a somewhat salty ocean.

Schenk, Paul

2002-01-01

310

THE OUTER DISKS OF DWARF IRREGULAR GALAXIES  

SciTech Connect

In order to explore the properties of extreme outer stellar disks, we obtained ultra-deep V and GALEX ultraviolet (UV) images of four dwarf irregular galaxies and one blue compact dwarf galaxy, and ultra-deep B images of three of these. Our V-band surface photometry extends to 29.5 mag arcsec{sup -2}. We convert the FUV and V-band photometry, along with H{alpha} photometry obtained in a larger survey, into radial star formation rate profiles that are sensitive to timescales from 10 Myr to the lifetime of the galaxy. We also obtained H I-line emission data and compare the stellar distributions, surface brightness profiles, and star formation rate profiles to H I-line emission maps, gas surface density profiles, and gas kinematics. Our data lead us to two general observations. First, the exponential disks in these irregular galaxies are extraordinarily regular. We observe that the stellar disks continue to decline exponentially as far as our measurements extend. In spite of lumpiness in the distribution of young stars and H I distributions and kinematics that have significant unordered motions, sporadic processes that have built the disks-star formation, radial movement of stars, and perhaps even perturbations from the outside-have, nevertheless, conspired to produce standard disk profiles. Second, there is a remarkable continuity of star formation throughout these disks over time. In four out of five of our galaxies the star formation rate in the outer disk measured from the FUV tracks that determined from the V-band, to within factors of five, requiring star formation at a fairly steady rate over the galaxy's lifetime. Yet, the H I surface density profiles generally decline with radius more shallowly than the stellar light, and the gas is marginally gravitationally stable against collapse into clouds. Outer stellar disks are challenging our concepts of star formation and disk growth and provide a critical environment in which to understand processes that mold galaxy disks.

Hunter, Deidre A.; Massey, Philip; Wilsey, Nick; Riabokin, Malanka [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Elmegreen, Bruce G. [IBM T. J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598 (United States); Oh, Se-Heon [Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701, Republic of South Africa (South Africa); Anderson, Ed [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011-6010 (United States); Nordgren, Tyler E., E-mail: dah@lowell.edu, E-mail: phil.massey@lowell.edu, E-mail: njw459@truman.edu, E-mail: riabokin@msu.edu, E-mail: bge@watson.ibm.com, E-mail: seheon-oh@ast.uct.ac.za, E-mail: Ed.Anderson@nau.edu, E-mail: tyler_nordgren@redlands.edu [Department of Physics, University of Redlands, 1200 East Colton Avenue, Redlands, CA 92373 (United States)

2011-10-15

311

Investigations on hard machining of Impax Hi Hard tool steel  

Microsoft Academic Search

In this paper, experimental investigations are carried out by end milling process on hardened tool steel, Impax Hi Hard (Hardness\\u000a 55 HRC) a newly developed tool steel material used by tool and die making industries. Experiments are performed with an aim\\u000a to study performance investigations of machining parameters such as cutting speed, feed, depth of cut and width of cut

Bala Murugan Gopalsamy; Biswanath Mondal; Sukamal Ghosh; Kristian Arntz; Fritz Klocke

2009-01-01

312

Glass shell manufacturing in space  

NASA Technical Reports Server (NTRS)

Highly-uniform, hollow glass spheres (shells), which are used for inertial confinement fusion targets, were formed from metal-organic gel powder feedstock in a vertical furnace. As a result of the rapid pyrolysis caused by the furnace, the gel is transformed to a shell in five distinct stages: (a) surface closure of the porous gel; (b) generation of a closed-cell foam structure in the gel; (c) spheridization of the gel and further expansion of the foam; (d) coalescence of the closed-cell foam to a single-void shell; and (e) fining of the glass shell. The heat transfer from the furnace to the falling gel particle was modeled to determine the effective heating rate of the gel. The model predicts the temperature history for a particle as a function of mass, dimensions, specific heat, and absorptance as well as furnace temperature profile and thermal conductivity of the furnace gas. A model was developed that predicts the gravity-induced degradation of shell concentricity in falling molten shells as a function of shell characteristics and time.

Downs, R. L.; Ebner, M. A.; Nolen, R. L., Jr.

1981-01-01

313

Nonconventional hard-metal compositions  

SciTech Connect

A novel hard-metal composition comprising borides and carbides of tungsten, nickel, and iron is made by reaction hot-pressing mixtures of elemental tungsten, nickel, and iron powders with small quantities of boron carbide. The hardness of these compositions is in the range of the hardest conventional tungsten carbide-cobalt compositions. It was subsequently determined that molybdenum can be substituted in part or totally for the tungsten in the composition with a minimum reduction in hardness. This new composition can be used in high-pressure anvils; it sustains higher pressures than commercial carbides without plastic deformation.

Sheinberg, H.

1982-01-01

314

HARD CLAM HYBRIDS FOR FLORIDAAQUACULTURE: HATCHERY CULTURE  

E-print Network

HARD CLAM HYBRIDS FOR FLORIDAAQUACULTURE: HATCHERY CULTURE John Scarpa: Harbor Branch Oceanographic and Aquatic Sciences, Gainesville, FL 32653 Introduction The hard clam (Mercenaria mercenaria notata summers of Florida. Southern hard clams, Mercenaria campechiensis, may have production traits

Florida, University of

315

Photometric properties of outer planetary satellites  

NASA Technical Reports Server (NTRS)

Optical broadband photometry for the satellites J6, J7, J8, S7, S9, U3, U4, and N1 and polarimetry for J6, obtained between 1970 and 1979, are presented. The outer Jovian satellites resemble C-type asteroids; J6 has a rotational lightcurve with a period of approximately 9.5 hr. The satellites beyond Jupiter also show C-like colors with the exception of S7 Hyperion. S9 Phoebe has a rotational lightcurve with period near either 11.25 or 21.1 hr. For U4 and N1 there is evidence for a lightcurve synchronous with the orbital revolution. The seven brighter Saturnian satellites show a regular relation between the ultraviolet dropoff and distance to the planet, probably related with differences in the rock component on their surfaces.

Degewij, J.; Zellner, B.; Andersson, L. E.

1980-01-01

316

In Outer Space without a Space Suit?  

E-print Network

The author proposes and investigates his old idea - a living human in space without the encumbrance of a complex space suit. Only in this condition can biological humanity seriously attempt to colonize space because all planets of Solar system (except the Earth) do not have suitable atmospheres. Aside from the issue of temperature, a suitable partial pressure of oxygen is lacking. In this case the main problem is how to satiate human blood with oxygen and delete carbonic acid gas (carbon dioxide). The proposed system would enable a person to function in outer space without a space suit and, for a long time, without food. That is useful also in the Earth for sustaining working men in an otherwise deadly atmosphere laden with lethal particulates (in case of nuclear, chemical or biological war), in underground confined spaces without fresh air, under water or a top high mountains above a height that can sustain respiration.

Alexander Bolonkin

2008-06-24

317

In Outer Space without a Space Suit?  

E-print Network

The author proposes and investigates his old idea - a living human in space without the encumbrance of a complex space suit. Only in this condition can biological humanity seriously attempt to colonize space because all planets of Solar system (except the Earth) do not have suitable atmospheres. Aside from the issue of temperature, a suitable partial pressure of oxygen is lacking. In this case the main problem is how to satiate human blood with oxygen and delete carbonic acid gas (carbon dioxide). The proposed system would enable a person to function in outer space without a space suit and, for a long time, without food. That is useful also in the Earth for sustaining working men in an otherwise deadly atmosphere laden with lethal particulates (in case of nuclear, chemical or biological war), in underground confined spaces without fresh air, under water or a top high mountains above a height that can sustain respiration.

Bolonkin, Alexander

2008-01-01

318

MHD wave breaking in the outer plasmasphere  

NASA Technical Reports Server (NTRS)

Empirical models of the average magnetospheric magnetic field, plasma density, and temperature distributions are used to construct a model of the distribution of MHD wave mode speeds within the magnetosphere. A persistent feature of the derived optical structure is a pronounced minimum of the wave speeds in the outer plasmasphere, i.e., a magnetospheric 'shoal'. This feature does not map along magnetic field lines, but is confined to the equatorial region, leading to a positive radial gradient of wave speeds near synchronous orbit. The breaking of earthward propagating disturbances in this region may play an essential role in the formation of the substorm injection boundary and in the creation of equatorially trapped warm ion distributions.

Moore, T. E.; Gallagher, D. L.; Horwitz, J. L.; Comfort, R. H.

1987-01-01

319

Metric theory of nematoelastic shells  

E-print Network

We consider three-dimensional reshaping of a thin nematoelastic film upon nematic-isotropic transition in the field of a charge one topological defect, leading to either cone or anticone (d-cone) shells. The analysis is based on the relation between the shell metric and the tensor order parameter under the assumption of no elastic deformation and volume change. The shape of the shell can be modified by doping, creating cones with curved generatrices. Anticones necessarily have an even number of radial creases. The curvature singularity at the apex is resolved due to decay of the nematic order parameter at the defect core.

L. M. Pismen

2014-12-01

320

Metric theory of nematoelastic shells  

NASA Astrophysics Data System (ADS)

We consider three-dimensional reshaping of a thin nematoelastic film upon nematic-isotropic transition in the field of a charge one topological defect, leading to either cone or anticone (d -cone) shells. The analysis is based on the relation between the shell metric and the tensor order parameter under the assumption of no elastic deformation and volume change. The shape of the shell can be modified by doping, creating cones with curved generatrices. Anticones necessarily have an even number of radial creases. The curvature singularity at the apex is resolved due to decay of the nematic order parameter at the defect core.

Pismen, L. M.

2014-12-01

321

Metric theory of nematoelastic shells.  

PubMed

We consider three-dimensional reshaping of a thin nematoelastic film upon nematic-isotropic transition in the field of a charge one topological defect, leading to either cone or anticone (d-cone) shells. The analysis is based on the relation between the shell metric and the tensor order parameter under the assumption of no elastic deformation and volume change. The shape of the shell can be modified by doping, creating cones with curved generatrices. Anticones necessarily have an even number of radial creases. The curvature singularity at the apex is resolved due to decay of the nematic order parameter at the defect core. PMID:25615035

Pismen, L M

2014-12-01

322

Carbon multi-shell cages.  

PubMed

Complex chemical compounds found as minerals or synthesized in labs evidenced a multi-shell structure. Also, fullerenes aggregate, randomly or following a well-defined geometry, in multi-shells. The way of space filling differs as a function of the dimensions and shape of the composing small cages. In this paper an attempt to build and evaluate the stability of several fullerene aggregates is made. The results show multi-shell covalently bonded structures with stability comparable to that of C60, the reference fullerene in nanoscience. The calculations were made at the DFTB and DFT levels of theory. PMID:24492624

Diudea, M V; Bende, A; Nagy, C L

2014-03-21

323

MicroShell Minimalist Shell for Xilinx Microprocessors  

NASA Technical Reports Server (NTRS)

MicroShell is a lightweight shell environment for engineers and software developers working with embedded microprocessors in Xilinx FPGAs. (MicroShell has also been successfully ported to run on ARM Cortex-M1 microprocessors in Actel ProASIC3 FPGAs, but without project-integration support.) Micro Shell decreases the time spent performing initial tests of field-programmable gate array (FPGA) designs, simplifies running customizable one-time-only experiments, and provides a familiar-feeling command-line interface. The program comes with a collection of useful functions and enables the designer to add an unlimited number of custom commands, which are callable from the command-line. The commands are parameterizable (using the C-based command-line parameter idiom), so the designer can use one function to exercise hardware with different values. Also, since many hardware peripherals instantiated in FPGAs have reasonably simple register-mapped I/O interfaces, the engineer can edit and view hardware parameter settings at any time without stopping the processor. MicroShell comes with a set of support scripts that interface seamlessly with Xilinx's EDK tool. Adding an instance of MicroShell to a project is as simple as marking a check box in a library configuration dialog box and specifying a software project directory. The support scripts then examine the hardware design, build design-specific functions, conditionally include processor-specific functions, and complete the compilation process. For code-size constrained designs, most of the stock functionality can be excluded from the compiled library. When all of the configurable options are removed from the binary, MicroShell has an unoptimized memory footprint of about 4.8 kB and a size-optimized footprint of about 2.3 kB. Since MicroShell allows unfettered access to all processor-accessible memory locations, it is possible to perform live patching on a running system. This can be useful, for instance, if a bug is discovered in a routine but the system cannot be rebooted: Shell allows a skilled operator to directly edit the binary executable in memory. With some forethought, MicroShell code can be located in a different memory location from custom code, permitting the custom functionality to be overwritten at any time without stopping the controlling shell.

Werne, Thomas A.

2011-01-01

324

Impulsive ion acceleration in earth's outer magnetosphere  

SciTech Connect

Considerable observational evidence is found that ions are accelerated to high energies in the outer magnetosphere during geomagnetic disturbances. The acceleration often appears to be quite impulsive causing temporally brief (10's of seconds), very intense bursts of ions in the distant plasma sheet as well as in the near-tail region. These ion bursts extend in energy from 10's of keV to over 1 MeV and are closely associated with substorm expansive phase onsets. Although the very energetic ions are not of dominant importance for magnetotail plasma dynamics, they serve as an important tracer population. Their absolute intensity and brief temporal appearance bespeaks a strong and rapid acceleration process in the near-tail, very probably involving large induced electric fields substantially greater than those associated with cross-tail potential drops. Subsequent to their impulsive acceleration, these ions are injected into the outer trapping regions forming ion ''drift echo'' events, as well as streaming tailward away from their acceleration site in the near-earth plasma sheet. Most auroral ion acceleration processes occur (or are greatly enhanced) during the time that these global magnetospheric events are occurring in the magnetotail. A qualitative model relating energetic ion populations to near-tail magnetic reconnection at substorm onset followed by global redistribution is quite successful in explaining the primary observational features. Recent measurements of the elemental composition and charge-states have proven valuable for showing the source (solar wind or ionosphere) of the original plasma population from which the ions were accelerated.

Baker, D.N.; Belian, R.D.

1985-01-01

325

Lateral interactions in the outer retina  

PubMed Central

Lateral interactions in the outer retina, particularly negative feedback from horizontal cells to cones and direct feed-forward input from horizontal cells to bipolar cells, play a number of important roles in early visual processing, such as generating center-surround receptive fields that enhance spatial discrimination. These circuits may also contribute to post-receptoral light adaptation and the generation of color opponency. In this review, we examine the contributions of horizontal cell feedback and feed-forward pathways to early visual processing. We begin by reviewing the properties of bipolar cell receptive fields, especially with respect to modulation of the bipolar receptive field surround by the ambient light level and to the contribution of horizontal cells to the surround. We then review evidence for and against three proposed mechanisms for negative feedback from horizontal cells to cones: 1) GABA release by horizontal cells, 2) ephaptic modulation of the cone pedicle membrane potential generated by currents flowing through hemigap junctions in horizontal cell dendrites, and 3) modulation of cone calcium currents (ICa) by changes in synaptic cleft proton levels. We also consider evidence for the presence of direct horizontal cell feed-forward input to bipolar cells and discuss a possible role for GABA at this synapse. We summarize proposed functions of horizontal cell feedback and feed-forward pathways. Finally, we examine the mechanisms and functions of two other forms of lateral interaction in the outer retina: negative feedback from horizontal cells to rods and positive feedback from horizontal cells to cones. PMID:22580106

Thoreson, Wallace B.; Mangel, Stuart C.

2012-01-01

326

Outer Planet Mission Studies Neptune Aerocapture  

NASA Technical Reports Server (NTRS)

Current and previous studies of orbiter missions to the outer planets have clearly identified high-energy aerocapture as a critical and enabling technology. Aerocapture involves the use of aerodynamic lift to fly a trajectory through a planet's atmosphere to sufficiently decelerate an entry vehicle to capture into planetary orbit. In the past, numerous studies of different configurations of lifting entry vehicles were studied for various planetary orbiter missions which identified aerocapture as a feasible concept yet complex and technically challenging. In order to determine the feasibility of high-speed aerocapture at the outer planets, an accurate trajectory simulation of the flight vehicle is the critical first step in the proposed research. Vehicle response to aerodynamic loading must be predicted accurately in the trajectory simulations. For several Neptune orbiter missions currently under study at the Jet Propulsion Laboratory (JPL), entry velocities relative to the rotating atmosphere ranging from 25 to 30 km/sec, are to be expected. Preliminary trajectory analysis has identified the various flow regimes the entry vehicle is expected to fly in the 8 1% H2 and 19% He atmosphere of Neptune. The size and mass of the vehicle are also determined by the launch vehicle constraints and orbiter spacecraft requirements. For a given baseline arrival conditions of an inertial entry velocity of 28 km/sec and an entry mass of 400 kg, a medium lift (L/D = 1), axisymmetric biconic shaped vehicle was selected in order to satisfy entry corridor width requirements expected for Neptune aerocapture. The analysis summarized in this study indicates that a biconic entry vehicle is a feasible concept for a Neptune aerocapture orbiter mission. The preliminary entry trajectory simulations has demonstrated adequate entry corridor control authority. Furthermore, estimates of the stagnation point heating environment has enabled the preliminary selection of candidate lightweight ceramic TPS materials.

Wercinski, Paul F.; Langhoff, Steven R. (Technical Monitor)

1997-01-01

327

Comparative study of shell swab and shell crush methods for the recovery of Salmonella from shell eggs.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Swabbing (SW) is the standard methodology for the recovery of resident microorganisms from shell eggs in Japan. A comparative study of shell swab (SW) and a shell crush (CR) technique was performed to recover the laboratory-inoculated Salmonella from shell eggs. It was found that the recovery of ...

328

Isotopic and chemical intra-shell variations in low-Mg calcite of rudist bivalves (Mollusca-Hippuritacea): disequilibrium fractionations and late Cretaceous seasonality  

Microsoft Academic Search

Isotopic (?13C, ?18O) and elemental (Mg, Sr, Mn, Fe) compositions were analysed in sclerochronological profiles of several shells of late Cretaceous\\u000a rudist bivalves from Greece, Turkey, Somalia and the Arabian Peninsula. The preservation of original compositions of low-Mg\\u000a calcite of outer shell layers is indicated by constant and high Sr, generally low Fe and Mn, and the preservation of fibrous-prismatic

T. Steuber

1999-01-01

329

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2010-07-01

330

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2010-07-01

331

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2013-07-01

332

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2012-07-01

333

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2011-07-01

334

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2014-07-01

335

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2013-07-01

336

30 CFR 77.1710-1 - Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Distinctively colored hard hats or hard caps; identification for newly...1710-1 Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2014-07-01

337

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2012-07-01

338

30 CFR 75.1720-1 - Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Distinctively colored hard hats, or hard caps; identification for newly...1720-1 Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively...

2011-07-01

339

Explanation and the Hard Problem  

Microsoft Academic Search

This paper argues that the form of explanation at issue in the hard problem of consciousness is scientifically irrelevant,\\u000a despite appearances to the contrary. In particular, it is argued that the ‘sense of understanding’ that plays a critical role\\u000a in the form of explanation implicated in the hard problem provides neither a necessary nor a sufficient condition on satisfactory\\u000a scientific

Wayne Wright

2007-01-01

340

Easy Problems are Sometimes Hard  

Microsoft Academic Search

We present a detailed experimental investigation of the easy-hard-easyphase transition for randomly generated instances of satisfiability problems.Problems in the hard part of the phase transition have been extensively usedfor benchmarking satisfiability algorithms. This study demonstrates thatproblem classes and regions of the phase transition previously thought tobe easy can sometimes be orders of magnitude more difficult than the worstproblems in problem

Ian P. Gent; Toby Walsh

1994-01-01

341

Sintered titanium carbide hard alloys  

Microsoft Academic Search

1.A study was made of the preparation of titanium carbide hard alloys with a nickel binder. It is shown that satisfactory mechanical properties (bend strength 107–115 kg\\/mm2, hardness 90–90.5 HRA) are exhibited by 80% TiC-20% Ni alloys produced from fine-milled mixtures by sintering in a vacuum of 5·10-3 mm Hg at a temperature of 1300‡C and an isothermal holding time

G. V. Samsonov; N. N. Sergeev; G. T. Dzodziev; V. K. Vitryanyuk; L. V. Latyaeva

1971-01-01

342

QPX Disease in Hard Clams  

NSDL National Science Digital Library

This New York SeaGrant PDF-brochure examines QPX (Quahog Parasite Unknown, a disease-causing parasite) as it relates to the hard clam fishery in New York. It discusses the origin of QPX, how it infects hard clams, where it has been found, signs of QPX disease, why people in New York should be concerned, and what is being done to control its spread.

Debra Barnes

343

Spitzer/Infrared Array Camera near-infrared features in the outer parts of S4G galaxies  

NASA Astrophysics Data System (ADS)

We present a catalogue and images of visually detected features, such as asymmetries, extensions, warps, shells, tidal tails, polar rings, and obvious signs of mergers or interactions, in the faint outer regions (at and outside of R25) of nearby galaxies. This catalogue can be used in future quantitative studies that examine galaxy evolution due to internal and external factors. We are able to reliably detect outer region features down to a brightness level of 0.03 MJy sr-1 pixel-1 at 3.6 ?m in the Spitzer Survey of Stellar Structure in Galaxies (S4G). We also tabulate companion galaxies. We find asymmetries in the outer isophotes in 22 ± 1 per cent of the sample. The asymmetry fraction does not correlate with galaxy classification as an interacting galaxy or merger remnant, or with the presence of companions. We also compare the detected features to similar features in galaxies taken from cosmological zoom re-simulations. The simulated images have a higher fraction (33 per cent) of outer disc asymmetries, which may be due to selection effects and an uncertain star formation threshold in the models. The asymmetries may have either an internal (e.g. lopsidedness due to dark halo asymmetry) or external origin.

Laine, Seppo; Knapen, Johan H.; Muñoz-Mateos, Juan-Carlos; Kim, Taehyun; Comerón, Sébastien; Martig, Marie; Holwerda, Benne W.; Athanassoula, E.; Bosma, Albert; Johansson, Peter H.; Erroz-Ferrer, Santiago; Gadotti, Dimitri A.; de Paz, Armando Gil; Hinz, Joannah; Laine, Jarkko; Laurikainen, Eija; Menéndez-Delmestre, Karín; Mizusawa, Trisha; Regan, Michael W.; Salo, Heikki; Sheth, Kartik; Seibert, Mark; Buta, Ronald J.; Cisternas, Mauricio; Elmegreen, Bruce G.; Elmegreen, Debra M.; Ho, Luis C.; Madore, Barry F.; Zaritsky, Dennis

2014-11-01

344

A Second Shell in the Fornax dSph Galaxy  

E-print Network

In the search for tidal structure in Galactic satellite systems, we have conducted a photometric survey over a 10 square degree area centred on the Fornax dSph galaxy. The survey was made in two colours, and the resulting colour-magnitude data were used as a mask to select candidate Fornax RGB stars, thereby increasing the contrast of Fornax stars to background sources in the outer regions. Previously, we reported the presence of a shell (age 2 Gyr) located towards the centre of Fornax. In this contribution we reveal a second shell, significantly larger than the first, located 1.3 degrees NW from the centre of Fornax, outside the nominal tidal radius. Moreover, the distribution of Fornax RGB stars reveals two lobes extending to the spatial limit of our survey, and aligned with the minor axis and with the two shells. These results support the hypothesis of a merger between Fornax and a gas-rich companion approximately 2 Gyr ago.

M. G. Coleman; G. S. Da Costa

2004-11-09

345

HR Del REMNANT ANATOMY USING TWO-DIMENSIONAL SPECTRAL DATA AND THREE-DIMENSIONAL PHOTOIONIZATION SHELL MODELS  

SciTech Connect

The HR Del nova remnant was observed with the IFU-GMOS at Gemini North. The spatially resolved spectral data cube was used in the kinematic, morphological, and abundance analysis of the ejecta. The line maps show a very clumpy shell with two main symmetric structures. The first one is the outer part of the shell seen in H{alpha}, which forms two rings projected in the sky plane. These ring structures correspond to a closed hourglass shape, first proposed by Harman and O'Brien. The equatorial emission enhancement is caused by the superimposed hourglass structures in the line of sight. The second structure seen only in the [O III] and [N II] maps is located along the polar directions inside the hourglass structure. Abundance gradients between the polar caps and equatorial region were not found. However, the outer part of the shell seems to be less abundant in oxygen and nitrogen than the inner regions. Detailed 2.5-dimensional photoionization modeling of the three-dimensional shell was performed using the mass distribution inferred from the observations and the presence of mass clumps. The resulting model grids are used to constrain the physical properties of the shell as well as the central ionizing source. A sequence of three-dimensional clumpy models including a disk-shaped ionization source is able to reproduce the ionization gradients between polar and equatorial regions of the shell. Differences between shell axial ratios in different lines can also be explained by aspherical illumination. A total shell mass of 9 x 10{sup -4} M {sub sun} is derived from these models. We estimate that 50%-70% of the shell mass is contained in neutral clumps with density contrast up to a factor of 30.

Moraes, Manoel [Rua do Matao, 1226, Cidade Universitaria, Sao Paulo, SP 05508-090 sala F-308 (Brazil); Diaz, Marcos [Rua do Matao, 1226, Cidade Universitaria, Sao Paulo, SP 05508-090 sala F-303 (Brazil)], E-mail: mcvmjr@astro.iag.usp.br, E-mail: marcos@astro.iag.usp.br

2009-12-15

346

Insulative laser shell coupler  

DOEpatents

A segmented coaxial laser shell assembly having at least two water jacket sections, two pairs of interconnection half rings, a dialectric break ring, and a pair of threaded ring sections. Each water jacket section with an inner tubular section that defines an inner laser cavity with water paths adjacent to at least a portion of the exterior of the inner tubular section, and mating faces at the end of the water jacket section through which the inner laser cavity opens and which defines at least one water port therethrough in communication with the water jackets. The water paths also define in their external surface a circumferential notch set back from and in close proximity to the mating face. The dielectric break ring has selected thickness and is placed between, and in coaxial alignment with, the mating faces of two of the adjacent water jacket sections. The break ring also defines an inner laser cavity of the same size and shape as the inner laser cavity of the water jacket sections and at least one water passage through the break ring to communicate with at least one water port through the mating faces of the water jacket sections.

Arnold, Phillip A. (Livermore, CA); Anderson, Andrew T. (Livermore, CA); Alger, Terry W. (Tracy, CA)

1994-01-01

347

Intergalactic shells at large redshift  

NASA Technical Reports Server (NTRS)

The intergalactic shells produced by galactic explosions at large redshift, whose interiors cool by inverse Compton scattering off the cosmic background radiation, have a characteristic angular size of about 1 arcmin at peak brightness. At z values lower than 2, the shells typically have a radius of 0.5 Mpc, a velocity of about 50 km/sec, a metal abundance of about 0.0001 of cosmic values, and strong radiation in H I(Lyman-alpha), He II 304 A, and the IR fine-structure lines of C II and Si II. The predicted extragalactic background emission from many shells, strongly peaked toward the UV, sets an upper limit to the number of exploding sources at z values of about 10. Shell absorption lines of H I, C II, Si II, and Fe II, which may be seen at more recent epochs in quasar spectra, may probe otherwise invisible explosions in the early universe.

Shull, J. M.; Silk, J.

1981-01-01

348

Shell Scores with Interactive Video.  

ERIC Educational Resources Information Center

Documents Shell Oil's success with interactive video training (IVT) and identifies the costs involved in this long-term investment. Provides guidelines for judging the effectiveness of IVT programs. (SK)

Zemke, Ron

1991-01-01

349

Stability of elastic grid shells  

E-print Network

The elastic grid shell is a solution that combines double curvature and ease of mounting. This structural system, based on the deformation of an initially at grid without shear stiffness was invented more than fifty years ...

Mesnil, Romain, M. Eng. Massachusetts Institute of Technology

2013-01-01

350

Collapsing thin shells with rotation  

NASA Astrophysics Data System (ADS)

We construct exact solutions describing the motion of rotating thin shells in a fully backreacted five-dimensional rotating black hole spacetime. The radial equation of motion follows from the Darmois-Israel junction conditions, where both interior and exterior geometries are taken to be equal angular momenta Myers-Perry solutions. We show that rotation generates anisotropic pressures and momentum along the shell. Gravitational collapse scenarios including rotation are analyzed and a new class of stationary solutions is introduced. Energy conditions for the anisotropic matter shell are briefly discussed. We find that the weak energy condition is not violated for the collapse scenario where the shell starts at rest from infinity, nor for the new class of stationary solutions in anti-de Sitter. We further prove that the cosmic censorship conjecture is always satisfied in our setup.

Delsate, Térence; Rocha, Jorge V.; Santarelli, Raphael

2014-06-01

351

Corrugated outer sheath gas-insulated transmission line  

DOEpatents

A gas-insulated transmission line includes two transmission line sections each of which are formed of a corrugated outer housing enclosing an inner high-voltage conductor disposed therein, with insulating support means supporting the inner conductor within the outer housing and an insulating gas providing electrical insulation therebetween. The outer housings in each section have smooth end sections at the longitudinal ends thereof which are joined together by joining means which provide for a sealing fixed joint.

Kemeny, George A. (Pittsburgh, PA); Cookson, Alan H. (Churchill Boro, PA)

1981-01-01

352

Sea Scallop Shell Lab Handout  

NSDL National Science Digital Library

Used in combination with the Sea Scallop Shell Lab teacher's guide, students will examine sea scallop shells to figure out as much as possible about the scallops living on the sea floor in one three important fishery grounds, Hudson Canyon, off New Bedford, MA, and George's Bank. The activity emphasizes observation, measurements, and basic calculations. The teacher's guide is available from the COSEE-NE OSEI resource site.

353

Nematic textures in spherical shells  

NASA Astrophysics Data System (ADS)

The equilibrium texture of nematic shells is studied as a function of their thickness. For ultrathin shells the ground state has four short (1)/(2) disclination lines but, as the thickness of the film increases, a three-dimensional escaped configuration composed of two pairs of half-hedgehogs becomes energetically favorable. We derive an exact solution for the nematic ground state in the one Frank constant approximation and study the stability of the corresponding texture against thermal fluctuations.

Vitelli, V.; Nelson, D. R.

2006-08-01

354

Unix et Programmation Shell Philippe Langevin  

E-print Network

Programmation Shell Automne 2013 4 / 1 #12;shell unix origine naissance de unix Parmi de nombreux hackers deux Programmation Shell Automne 2013 5 / 1 #12;shell unix origine naissance de unix Parmi de nombreux hackers deux naissance de unix Parmi de nombreux hackers deux pionniers des Bell labs sont `a l'origine du syst`eme unix

Faccanoni, Gloria

355

MOVEMENTS OF SMALL SOFT-SHELL CLAMS  

E-print Network

MOVEMENTS OF SMALL SOFT-SHELL CLAMS Marine Biological Labootory X, I B R A K Y JUL 21 l'db5 WOODS MOVEMENTS OF SMALL SOFT-SHELL CLAMS (MX^ MANARJAJ By Osgood R . Smith Fishery Research Biologist Special-shell clams, (MYA ARENARIA) The fact that small soft -shell clams can come up out of the soil, can move

356

Biogenesis of outer membranes in Gram-negative bacteria.  

PubMed

The outer membrane, an essential organelle of Gram-negative bacteria, is composed of four major components: lipopolysaccharide, phospholipids, beta-barrel proteins, and lipoproteins. The mechanisms underlying the transport of these components to outer membranes are currently under extensive examination. Among them, the sorting of lipoproteins to the outer membrane of Escherichia coli has been clarified in detail. The Lol system, composed of five proteins, catalyzes outer membrane sorting of lipoproteins. Various Lpt proteins have recently been identified as factors involved in the transport of lipopolysaccharide to the outer membrane, although the mechanism remains largely unknown. Proteins with alpha-helical membrane spanning segments are found in the inner membrane, whereas amphipathic beta-barrel proteins span the outer membrane. These beta-barrel proteins are inserted into the outer membranes through a central core protein BamA (YaeT) with the help of four outer membrane lipoproteins. In contrast, little is known about how phospholipids are transported to the outer membrane. PMID:19270402

Tokuda, Hajime

2009-03-23

357

Elastic stability of cylindrical shells with soft elastic cores: Biomimicking natural tubular structures  

NASA Astrophysics Data System (ADS)

Thin walled cylindrical shell structures are widespread in nature: examples include plant stems, porcupine quills, and hedgehog spines. All have an outer shell of almost fully dense material supported by a low density, cellular core. In nature, all are loaded in combination of axial compression and bending: failure is typically by buckling. Natural structures are often optimized. Here we have analyzed the elastic buckling of a thin cylindrical shell supported by an elastic core to show that this structural configuration achieves significant weight saving over a hollow cylinder. The results of the analysis are compared with data from an extensive experimental program on uniaxial compression and four point bending tests on silicone rubber shells with and without compliant foam cores. The analysis describes the results of the mechanical tests well. Characterization of the microstructures of several natural tubular structures with foamlike cores (plant stems, quills, and spines) revealed them to be close to the optimal configurations predicted by the analytical model. Biomimicking of natural cylindrical shell structures and evolutionary design processes may offer the potential to increase the mechanical efficiency of engineering cylindrical shells.

Karam, Gebran Nizar

1994-01-01

358

Shell-core bi-layered scaffolds for engineering of vascularized osteon-like structures.  

PubMed

Bottom-up assembly of osteon-like structures into large tissue constructs represents a promising and practical strategy toward the formation of hierarchical cortical bone. Here, a unique two-step approach, i.e., the combination of electrospinning and twin screw extrusion (TSE) techniques was used to fabricate a microfilament/nanofiber shell-core scaffold that could precisely control the spatial distribution of different types of cells to form vascularized osteon-like structures. The scaffold contained a helical outer shell consisting of porous microfilament coils of polycaprolactone (PCL) and biphasic calcium phosphates (BCP) that wound around a hollow electrospun PCL nanofibrous tube (the core). The porous helical shell supported the formation of bone-like tissues, while the luminal surface of nanofibrous core enabled endothelialization to mimic the function of Haversian canal. Culture of mouse pre-osteoblasts (POBs, MC 3T3-E1) onto the coil shells revealed that coils with pitch sizes greater than 135 ?m, in the presence of BCP, favored the proliferation and osteogenic differentiation of POBs. The luminal surface of PCL nanofibrous core supported the adhesion and spreading of mouse endothelial cells (ECs, MS-1) to form a continuous endothelial lining with the function similar to blood vessels. Taken together, the shell-core bi-layered scaffolds with porous, coil-like shell and nanofibrous tubular cores represent a new scaffolding technology base for the creation of osteon analogs. PMID:23896002

Chen, Xuening; Ergun, Asli; Gevgilili, Halil; Ozkan, Seher; Kalyon, Dilhan M; Wang, Hongjun

2013-11-01

359

A Yolk-Shell Design for Stabilized and Scalable Li-Ion Battery Alloy Anodes  

SciTech Connect

Silicon is regarded as one of the most promising anode materials for next generation lithium-ion batteries. For use in practical applications, a Si electrode must have high capacity, long cycle life, high efficiency, and the fabrication must be industrially scalable. Here, we design and fabricate a yolk-shell structure to meet all these needs. The fabrication is carried out without special equipment and mostly at room temperature. Commercially available Si nanoparticles are completely sealed inside conformal, thin, self-supporting carbon shells, with rationally designed void space in between the particles and the shell. The well-defined void space allows the Si particles to expand freely without breaking the outer carbon shell, therefore stabilizing the solid-electrolyte interphase on the shell surface. High capacity (?2800 mAh/g at C/10), long cycle life (1000 cycles with 74% capacity retention), and high Coulombic efficiency (99.84%) have been realized in this yolk-shell structured Si electrode.

Liu, Nian; Wu, Hui; Mcdowell, Matthew T.; Yao, Yan; Wang, Chong M.; Cui, Yi

2012-05-02

360

Simulating the Outer Radiation Belt During the Rising Phase of Solar Cycle 24  

NASA Technical Reports Server (NTRS)

After prolonged period of solar minimum, there has been an increase in solar activity and its terrestrial consequences. We are in the midst of the rising phase of solar cycle 24, which began in January 2008. During the initial portion of the cycle, moderate geomagnetic storms occurred follow the 27 day solar rotation. Most of the storms were accompanied by increases in electron fluxes in the outer radiation belt. These enhancements were often preceded with rapid dropout at high L shells. We seek to understand the similarities and differences in radiation belt behavior during the active times observed during the of this solar cycle. This study includes extensive data and simulations our Radiation Belt Environment Model. We identify the processes, transport and wave-particle interactions, that are responsible for the flux dropout and the enhancement and recovery.

Fok, Mei-Ching; Glocer, Alex; Zheng, Qiuhua; Chen, Sheng-Hsien; Kanekal, Shri; Nagai, Tsungunobu; Albert, Jay

2011-01-01

361

A 21 centimeter line survey of a region around four outer galaxy open clusters  

NASA Technical Reports Server (NTRS)

To investigate the role of atomic gas in the interaction of massive stars with the interstellar medium, a 21 cm survey was made of a region surrounding four young, outer Galaxy open clusters, NGC 281, 433, 436, and 457. A rectangular area ranging in Galactic longitude from 115 to 133 deg, and in latitude from -10 to -1 deg, was observed with the NRAO 140 foot telescope. Most of this region was fully sampled, resulting in spatial resolution equal to the telescope's 21 arcmin beamwidth. The data are presented as longitude-latitude and latitude-velocity contour maps. A catalog of atomic gas features (e.g., clouds, filaments, and shells) is given.

Leisawitz, David; De Geus, Eugene J.

1991-01-01

362

On implementation of a nonlinear four node shell finite element for thin multilayered elastic shells  

Microsoft Academic Search

A simple non-linear stress resultant four node shell finite element is presented. The underlying shell theory is developed from the three dimensional continuum theory via standard assumptions on the displacement field. A model for thin shells is obtained by approximating terms describing the shell geometry. In this work the rotation of the shell director is parameterized by the two Euler

B. Brank; F. B. Damjani?; D. Peric

1995-01-01

363

Insight into finite element shell discretizations by use of the “basic shell mathematical model”  

Microsoft Academic Search

The objective of this paper is to gain insight into finite element discretizations of shells using the basic shell mathematical model and, in particular, regarding the sources of “locking”. We briefly review the “basic shell mathematical model” and present a formulation of shell finite elements based on this model. These shell finite elements are equivalent to the widely-used continuum mechanics

Phill-Seung Lee; Klaus-Jürgen Bathe

2005-01-01

364

Structural basis for the fracture toughness of the shell of the conch Strombus gigas  

NASA Astrophysics Data System (ADS)

Natural composite materials are renowned for their mechanical strength and toughness: despite being highly mineralized, with the organic component constituting not more than a few per cent of the composite material, the fracture toughness exceeds that of single crystals of the pure mineral by two to three orders of magnitude. The judicious placement of the organic matrix, relative to the mineral phase, and the hierarchical structural architecture extending over several distinct length scales both play crucial roles in the mechanical response of natural composites to external loads. Here we use transmission electron microscopy studies and beam bending experiments to show that the resistance of the shell of the conch Strombus gigas to catastrophic fracture can be understood quantitatively by invoking two energy-dissipating mechanisms: multiple microcracking in the outer layers at low mechanical loads, and crack bridging in the shell's tougher middle layers at higher loads. Both mechanisms are intimately associated with the so-called crossed lamellar microarchitecture of the shell, which provides for `channel' cracking in the outer layers and uncracked structural features that bridge crack surfaces, thereby significantly increasing the work of fracture, and hence the toughness, of the material. Despite a high mineral content of about 99% (by volume) of aragonite, the shell of Strombus gigas can thus be considered a `ceramic plywood', and can guide the biomimetic design of tough, lightweight structures.

Kamat, S.; Su, X.; Ballarini, R.; Heuer, A. H.

2000-06-01

365

Structural basis for the fracture toughness of the shell of the conch Strombus gigas.  

PubMed

Natural composite materials are renowned for their mechanical strength and toughness: despite being highly mineralized, with the organic component constituting not more than a few per cent of the composite material, the fracture toughness exceeds that of single crystals of the pure mineral by two to three orders of magnitude. The judicious placement of the organic matrix, relative to the mineral phase, and the hierarchical structural architecture extending over several distinct length scales both play crucial roles in the mechanical response of natural composites to external loads. Here we use transmission electron microscopy studies and beam bending experiments to show that the resistance of the shell of the conch Strombus gigas to catastrophic fracture can be understood quantitatively by invoking two energy-dissipating mechanisms: multiple microcracking in the outer layers at low mechanical loads, and crack bridging in the shell's tougher middle layers at higher loads. Both mechanisms are intimately associated with the so-called crossed lamellar microarchitecture of the shell, which provides for 'channel' cracking in the outer layers and uncracked structural features that bridge crack surfaces, thereby significantly increasing the work of fracture, and hence the toughness, of the material. Despite a high mineral content of about 99% (by volume) of aragonite, the shell of Strombus gigas can thus be considered a 'ceramic plywood' and can guide the biomimetic design of tough, lightweight structures. PMID:10890440

Kamat, S; Su, X; Ballarini, R; Heuer, A H

2000-06-29

366

Hard Hat Use and Inspection Hard hats are an important piece of personal protective equipment (PPE). Hard hats worn  

E-print Network

Hard Hat Use and Inspection Hard hats are an important piece of personal protective equipment (PPE). Hard hats worn at Berkeley Lab must comply with the requirements of ANSI Z89.1 for impact protection follow manufacturer's recommendations for specific inspection procedures. Hard Hat Inspection - Bullard

Eisen, Michael

367

Characterization of core-shell calcium-alginate macrocapsules fabricated by electro-coextrusion.  

PubMed

Spherical macrocapsules, where calcium-alginate shell enclosed olive oil as a model core medium, were fabricated by electro-coextrusion. The effects of three key process factors, including alginate concentration in shell fluid (0.5-4.0%), shell-to-core flow rate ratio (4-12 at a fixed core flow rate of 0.05 mL/min), and applied voltage (0-10 kV), on the morphological and textural characteristics of the macrocapsules were analyzed using response surface methodology. The analysis showed that the diameter, shell thickness, hardness, and breaking energy of the macrocapsules were in the ranges of 0.89-1.61 mm, 17.4-66.4 ?m, 1.37-11.01 N, and 0.34-6.90 mJ, respectively, and strongly influenced by all the three factors, except that the surface appearance was only significantly affected by the shell-to-core flow rate ratio. The process factors were also optimized for the practically useful macrocapsules, having non-oily surface and hardness larger than 3 N, using a graphical optimization technique. PMID:24463268

Phawaphuthanon, Natthiya; Behnam, Shabnam; Koo, Song Yi; Pan, Cheol-Ho; Chung, Donghwa

2014-04-01

368

Prevelance and Distribution of QPX, Quahog Parasite Unknown, in Hard Clams Mercenaria Mercenaria in Virginia, USA  

NSDL National Science Digital Library

This Diseases of Aquatic Organisms abstract serves as the first documentation of QPX (Quahog Parasite Unknown, a parasite affecting hard shell clams) in the state of Virginia. It reports findings from a sampling program performed in 1996 and 1997 that showed light to moderate parasite intensity ranging from 4% to 48% of each sampling period. At the time this article was published, QPX had not had a significant impact on Virginia's hard clam fishery and aquaculture industry, but the authors recommend continued monitoring and research.

Burreson, Eugene M.

369

Influence of algal and suspended sediment concentrations on the feeding physiology of the hard clam Mercenaria mercenaria  

Microsoft Academic Search

Short-term laboratory feeding experiments were conducted to determine the response of the hard clam Mercenaria mercenaria (L.) (32 mm in mean shell length) to increasing sediment concentrations. Clams were fed mixed suspensions of Pseudoisochrysis paradoxa (50 and 150 cells µl-1) and bottom sediments (0 to 44 mg l-1). Algal ingestion rate deelined with increasing sediment loads. This resulted primarily from

V. M. Bricelj; R. E. Malouf

1984-01-01

370

The Outer Heliosphere: The Next Frontiers  

NASA Astrophysics Data System (ADS)

The 11th COSPAR Colloquium "The Outer Heliosphere: The Next Frontiers" was held in Potsdam, Germany, from July 24 to 28, 2000, and is the second dedicated to this subject after the first one held in Warsaw, Poland in 1989. Roughly a century has passed after the first ideas by Oliver Lodge, George Francis Fitzgerald and Kristan Birkeland about particle clouds emanating from the Sun and interacting with the Earth environment. Only a few decades after the formulation of the concepts of a continuous solar corpuscular radiation by Ludwig Bierman and a solar wind by Eugene Parker, heliospheric physics has evolved into an important branch of astrophysical research. Numerous spacecraft missions have increased the knowledge about the heliosphere tremendously. Now, at the beginning of a new millenium it seems possible, by newly developed propulasion technologies to send a spacecraft beyond the boundaries of the heliosphere. Such an Interstellar Proce will start the in-situ exploration of interstellar space and, thus, can be considered as the first true astrophysical spacecraft. The year 2000 appeared to be a highly welcome occassion to review the achievements since the last COSPAR Colloquia 11 years ago, to summarize the present developments and to give new impulse for future activities in heliospheric research.

Scherer, K.; Fichtner, Horst; Fahr, Hans Jörg; Marsch, Eckart

371

The Outer Heliosphere: The Next Frontier  

NASA Astrophysics Data System (ADS)

Only a few decades after the formulation of the concept of a continuous solar corpus- cular radiation by Ludwig Biermann and a solar wind by Eugene Parker, heliospheric physics has evolved into an important branch of astrophysical research. The solar wind forms a bubble, called the heliosphere, in the local interstellar medium, within which the solar system resides and whose size and properties are determined by the manner in which the solar wind and the partially ionized local interstellar medium are coupled. In the last decade, great progress has been made in our understanding of the physical processes thought to describe the outer heliosphere. Numerous spacecraft missions have increased our knowledge about the large-scale structure, the properties, and the character of the heliosphere tremendously. of these, the ageing spacecraft Voyager 1,2 might encounter the inner border of the heliospheric boundary region in the not too distant future. Now, at the beginning of a new millenium, it seems possible, by newly developed technologies to send an interstellar probe beyond the boundaries of the he- liosphere, in order to explore the local interstellar medium in situ. We shall review our basic understanding of global heliospheric structure, emphasizing the importance of the LISM-solar wind coupling, emphasizing the demands and constraints that this places on a mission to the edge of interstellar space.

Heber, B.; Zank, G. P.

372

THE OUTER MAGNETIC FIELD OF L183  

SciTech Connect

The L183 (= L134N) dark molecular cloud has been probed using deep near-infrared imaging polarimetry of stars to beyond 14 mag in H band (1.6 {mu}m), using the Mimir instrument on the 1.83 m Perkins Telescope. Nearly 400 arcmin{sup 2} were surveyed, including the dense core in L183, as seen in WISE Band 3 (12 {mu}m) extinction, and the near surroundings, revealing 35 stars with either detected polarizations or significant upper limits. Stars with detected polarizations are reddened if closer than 8 arcmin (0.25 pc at the 110 pc cloud distance) and unreddened beyond. The polarimetric sample probes as close to the core as 3 arcmin (0.1 pc), where A{sub V} {approx} 14 mag. Compared to the relatively unextincted surrounding stars, the reddened stars show no increase in polarization with extinction, suggesting that all of the polarization is induced in the outer layers of the cloud. This 0.25 pc radius envelope magnetic field does show a strong interaction with the L183 dark cloud. The envelope field is also virtually perpendicular, on the plane of the sky, to the field seen at 850 {mu}m, though more closely aligned with the rotation axis of the dense gas core. The physical size scale at which the envelope and the core magnetic fields either decouple from each other or strongly modify their directions must be inside the 0.1 pc region probed here.

Clemens, Dan P., E-mail: clemens@bu.edu [Institute for Astrophysical Research, Boston University, 725 Commonwealth Ave, Boston, MA 02215 (United States)

2012-03-20

373

Infrared observations of outer planet satellites  

NASA Technical Reports Server (NTRS)

This task supports IR observations of the outer planet satellites. These data provide vital information about the thermophysical properties of satellite surfaces, including internal heat sources for Io. Observations include both broad and narrow band measurementsin the 2 to 20 micrometer spectral range. The program in the last year has aimed at obtaining lonitude coverage on Io to establish stability of hot spot patterns previously reported. Several runs produced the most complete data set for an apparition since the start of the program. Unfortunately, bad weather limited coverage of key longitude ranges containing the largest known hot spot Loki. Among the preliminary results is the observation of an outburst in Io's thermal flux that was measured at 4.8, 8.7 and 20 micrometer. Analysis of the data has given the best evidence to date of silicate volcanism on Io; this is one of the most significant pieces of the puzzle as to the relative roles of silicate and sulfur volcanism on Io. Researchers are collaborating with J. Goguen (NRC RRA to finish reduction of mutual event data, which have already improved ephermeris information for the satellites. The data appear to place significant limits on the characteristics of any leading side hot spots.

Johnson, T. V.

1988-01-01

374

Thermal plasma in outer planet magnetospheres  

NASA Technical Reports Server (NTRS)

The plasma environments of the outer planets are a study in contrasts. The magnetosphere of Jupiter is dominated by the prodigious plasma output of Io, with losses due to diffusion driven by mass loading. At Saturn, the small icy satellites are the major sources of plasma for the inner magnetosphere. The low mass loading rates there imply that the densities of the plasma tori are limited by dissociative recombination, rather than diffusive transport. At Uranus, the icy satellites are negligible plasma sources compared to the input from the extended neutral hydrogen cloud and the ionosphere. Convection driven by the solar wind penetrates deep into the inner magnetosphere because of the unique orientation of the rotation axis of Uranus. The expected magnetosphere of Neptune is similar to that of Saturn and Jupiter, with Triton, the ring arcs, and the planet as possible plasma sources. The Voyager 2 encounter with Neptune holds out the hope of a passage through a nonterrestrial auroral region, a unique event in planetary exploration.

Belcher, J. W.; Mcnutt, R. L., Jr.; Richardson, J. D.

1990-01-01

375

The effects of laterally varying icy shell structure on the tidal response of Europa and Ganymede  

NASA Astrophysics Data System (ADS)

One of the long-sought objectives of an icy moon orbiter or fly-by mission, has been to use tidal observations to help determine the existence of a liquid ocean and characteristics of the overlying icy shell. The radio science component of such a mission could be used to estimate the tidal potential Love number k2 for gravity. And if there is an on-board laser altimeter, it could be used to determine the radial displacement Love number h2. Knowledge of either of those Love numbers could provide information on the presence of an ocean beneath the icy outer shell, and the two Love numbers could be combined to place constraints on the thickness of the icy shell. Though if a subsurface ocean exists, complications could conceivably arise if the icy outer shell has significant lateral variations in elastic thickness or shear modulus, or if the ocean is not global in extent so that the icy shell is grounded in places but floating in others. In these cases, the tidal deformation pattern would not be represented as the sum of degree 2 harmonics, and so the results could not be characterized in terms of a single Love number. In this study, by solving a set of tidal loading problems with laterally variable icy shell structures (for which the existence of an ocean layer is assumed), we investigate how those structures might complicate the interpretation of the tide measurements, and we discuss how to extract information regarding the interior structure of Ganymede and Europa from measurements of their tidal response.

Wahr, J. M.; A, G.; Zhong, S.

2013-12-01

376

The Complexity of Hardness Amplification and Derandomization  

E-print Network

The Complexity of Hardness Amplification and Derandomization A thesis presented by Emanuele Viola Emanuele Viola The Complexity of Hardness Amplification and Derandomization Abstract This thesis studies of hardness amplification and deran­ domization. Hardness amplification is the task of taking a function

Viola, Emanuele

377

Using Nondeterminism to Amplify Hardness Alexander Healy  

E-print Network

Using Nondeterminism to Amplify Hardness Alexander Healy Salil Vadhan Harvard University Emanuele Viola ABSTRACT We revisit the problem of hardness amplification in NP, as recently studied by O) , we amplify to hardness 1/2 - 1/n(1) . 2. If s(n) = 2n(1) , we amplify to hardness 1/2-1/2n(1) . 3

Viola, Emanuele

378

Ultra-strong surface plasmon amplification characteristic of a spaser based on gold-silver core-shell nanorods  

NASA Astrophysics Data System (ADS)

We proposed an efficient spaser based on gold-silver core-shell nanorods (NRs) encapsulated by an outer silica shell doped with a gain medium. The optical characteristics of the spaser were numerically simulated based on the finite element method (FEM). The results showed that the localized surface plasmon resonance (LSPR) amplification characteristics of the spaser strongly depend on the thickness of silver shell, the aspect ratio of the inner gold NRs, and the polarization direction of the incident light. And, the maximum absolute value of optical cross-section of the spaser can reach 21,824 ?m2, which is about 1115, 523, and 18 times higher than that of spasers based on the gold NRs, the silver NRs, and the silver-gold core-shell NRs, respectively. The ultra-strong surface plasmon amplification characteristics of the spaser have potential applications in optical information storage, high sensitivity biochemical sensing, and medical engineering.

Zhang, Li; Zhou, Jun; Zhang, Haopeng; Jiang, Tao; Lou, Cibo

2015-03-01

379

Europa's Icy Shell: A Bridge Between Its Surface and Ocean  

NASA Technical Reports Server (NTRS)

Europa, a Moon-sized, ice-covered satellite of Jupiter, is second only to Mars in its astrobiological potential. Beneath the icy surface, an ocean up to 150 km deep is thought to exist, providing a potential habitat for life,and a tempting target for future space missions. The Galileo mission to the Jovian system recently ended, but there are already long-range plans to send much more capable spacecraft,such as the proposed Jupiter Icy Moons Orbiter (JIMO), to take a closer look at Europa and her siblings, Ganymede and Callisto, some time in the next two decades. Europak outer icy shell is the only interface between this putative ocean and the surface, but many aspects of this shell are presently poorly understood; in particular, its composition, thickness, deformational history, and mechanical properties. To discuss the ice shell and our current understanding of it, 78 scientists from the terrestrial and planetary science communities in the United States and Europe gathered for a 3-day workshop hosted by the Lunar and Planetary Institute in Houston in February. A key goal was to bring researchers from disparate disciplines together to discuss the importance and limitations of available data on Europa with a post-Galileo perspective. The workshop featured 2 days of reviews and contributed talks on the composition, physical properties, stratigraphy, tectonics, and future exploration of the ice shell and underlying ocean. The final morning included an extended discussion period, moderated by a panel of noted experts, highlighting outstanding questions and areas requiring future research.

Schenk, Paul; Mimmo, Francis; Prockter, Louise

2004-01-01

380

Observational evidence of competing source, loss, and transport processes for relativistic electrons in Earth's outer radiation belt  

NASA Astrophysics Data System (ADS)

Earth’s outer electron radiation belt is a region of extreme variability, with relativistic electron intensities changing by orders of magnitude over time scales ranging from minutes to years. Extreme variations of outer belt electrons ultimately result from the relative impacts of various competing source (and acceleration), loss, and transport processes. Most of these processes involve wave-particle interactions between outer belt electrons and different types of plasma waves in the inner magnetosphere, and in turn, the activity of these waves depends on different solar wind and magnetospheric driving conditions and thus can vary drastically from event to event. Using multipoint analysis with data from NASA’s Van Allen Probes, THEMIS, and SAMPEX missions, NOAA’s GOES and POES constellations, and ground-based observatories, we present results from case studies revealing how different source/acceleration and loss mechanisms compete during active periods to result in drastically different distributions of outer belt electrons. By using a combination of low-Earth orbiting and high-altitude-equatorial orbiting satellites, we briefly review how it is possible to get a much more complete picture of certain wave activity and electron losses over the full range of MLTs and L-shells throughout the radiation belt. We then show example cases highlighting the importance of particular mechanisms, including: substorm injections and whistler-mode chorus waves for the source and acceleration of relativistic electrons; magnetopause shadowing and wave-particle interactions with EMIC waves for sudden losses; and ULF wave activity for driving radial transport, a process which is important for redistributing relativistic electrons, contributing both to acceleration and loss processes. We show how relativistic electron enhancement events involve local acceleration that is consistent with wave-particle interactions between a seed population of 10s to 100s of keV electrons, with a source in the plasma sheet, and chorus waves. We show how sudden losses during outer belt dropout events are dominated at higher L-shells (L>~4) by magnetopause shadowing and outward radial transport, which is effective over the full ranges of energy and equatorial pitch angle of outer belt electrons, but at lower L-shells near the plasmapause, energy and pitch angle dependent losses can also occur and are consistent with rapid scattering by interactions between relativistic electrons and EMIC waves. We show cases demonstrating how these different processes occur simultaneously during active periods, with relative effects that vary as a function of L-shell and electron energy and pitch angle. Ultimately, our results highlight the complexity of competing source/acceleration, loss, and transport processes in Earth’s outer radiation belt and the necessity of using multipoint observations to disambiguate between them for future studies.

Turner, Drew; Mann, Ian; Usanova, Maria; Rodriguez, Juan; Henderson, Mike; Angelopoulos, Vassilis; Morley, Steven; Claudepierre, Seth; Li, Wen; Kellerman, Adam; Boyd, Alexander; Kim, Kyung-Chan

381

Puzzling outer-density profile of the dark matter halo in the Andromeda galaxy  

NASA Astrophysics Data System (ADS)

The cold dark matter (CDM) cosmology, which is the standard theory of the structure formation in the universe, predicts that the outer density profile of dark matter halos decreases with the cube of distance from the center. However, so far not much effort has been expended in examining this hypothesis. In the halo of the Andromeda galaxy (M 31), large-scale stellar structures detected by the recent observations provide a potentially suitable window to investigate the mass-density distribution of the dark matter halo. We explore the density structure of the dark matter halo in M 31 using an N-body simulation of the interaction between an accreting satellite galaxy and M 31. To reproduce the Andromeda Giant Southern Stream and the stellar shells at the east and west sides of M 31, we find the sufficient condition for the power-law index ? of the outer density distribution of the dark matter halo. The best-fitting parameter is ? = -3.7, which is steeper than the CDM prediction.

Kirihara, Takanobu; Miki, Yohei; Mori, Masao

2014-12-01

382

Barotropic instability in the tropical cyclone outer region  

Microsoft Academic Search

The growth of asymmetric perturbations and their interactions with the symmetric flow are investigated for wind profiles in a tropical cyclone with instability in its outer region. Three tangential wind profiles are examined: TC1, a strong barotropic instability profile in the outer region; TC2, a stable wind profile; and TC3, a weaker instability profile comparing to TC1 with a larger

Jiayi Peng; Tim Li; Melinda S. Peng; Xuyang Ge

2009-01-01

383

Outer hair cell active force generation in the cochlear environment  

E-print Network

Outer hair cell active force generation in the cochlear environment Zhijie Liao, Shengran Feng Outer hair cells are critical to the amplification and frequency selectivity of the mammalian ear acting hair cells are electromotile, and they are strategically located in the cochlea to generate an active

Popel, Aleksander S.

384

Prestin is the motor protein of cochlear outer hair cells  

Microsoft Academic Search

The outer and inner hair cells of the mammalian cochlea perform different functions. In response to changes in membrane potential, the cylindrical outer hair cell rapidly alters its length and stiffness. These mechanical changes, driven by putative molecular motors, are assumed to produce amplification of vibrations in the cochlea that are transduced by inner hair cells. Here we have identified

Jing Zheng; Weixing Shen; David Z. Z. He; Kevin B. Long; Laird D. Madison; Peter Dallos

2000-01-01

385

Research paper Fast cochlear amplification with slow outer hair cells  

E-print Network

Research paper Fast cochlear amplification with slow outer hair cells Timothy K. Lu a,b , Serhii hair cells (OHCs) produce mechanical amplification over the entire audio-frequency range (up to 100 k reserved. Keywords: Cochlear amplifier; Outer hair cell; Receptor potential; Membrane time constant low

Sarpeshkar, Rahul

386

Identification of Major Outer Surface Proteins of Streptococcus agalactiae  

Microsoft Academic Search

To identify the major outer surface proteins of Streptococcus agalactiae (group B streptococcus), a proteomic analysis was undertaken. An extract of the outer surface proteins was separated by two-dimensional electro- phoresis. The visualized spots were identified through a combination of peptide sequencing and reverse genetic methodologies. Of the 30 major spots identified as S. agalactiae specific, 27 have been identified.

Martin J. G. Hughes; Joanne C. Moore; Rebecca Wilson; Philippa K. Pribul; Zabin N. Younes; Richard J. Dobson; Paul Everest; Andrew J. Reason; Joanne M. Redfern; Fiona M. Greer; Thanai Paxton; Maria Panico; Howard R. Morris; Robert G. Feldman; Joseph D. Santangelo

2002-01-01

387

Leptospira: A Spirochete with a Hybrid Outer Membrane  

PubMed Central

Summary Leptospira is a genus of spirochetes that includes organisms with a variety of lifestyles ranging from aquatic saprophytes to invasive pathogens. Adaptation to a wide variety of environmental conditions has required leptospires to acquire a large genome and a complex outer membrane with features that are unique among bacteria. The most abundant surface-exposed outer membrane proteins are lipoproteins that are integrated into the lipid bilayer by amino terminal fatty acids. In contrast to many spirochetes, the leptospiral outer membrane also includes lipopolysaccharide and many homologues of well-known beta-barrel transmembrane outer membrane proteins. Research on leptospiral transmembrane outer membrane proteins has lagged behind studies of lipoproteins because of their aberrant behavior by Triton X-114 detergent fractionation. For this reason, transmembrane outer membrane proteins are best characterized by assessing membrane integration and surface exposure. Not surprisingly, some outer membrane proteins that mediate host-pathogen interactions are strongly regulated by conditions found in mammalian host tissues. For example, the leptospiral immunoglobulin-like (Lig) repeat proteins are dramatically induced by osmolarity and mediate interactions with host extracellular matrix proteins. Development of molecular genetic tools are making it possible to finally understand the roles of these and other outer membrane proteins in mechanisms of leptospiral pathogenesis. PMID:20598085

Haake, David A; Matsunaga, James

2010-01-01

388

Radioisotope Reduction Using Solar Power for Outer Planetary Missions  

Microsoft Academic Search

Radioisotope power systems have historically been (and still are) the power system of choice from a mass and size perspective for outer planetary missions. High demand for and limited availability of radioisotope fuel has made it necessary to investigate alternatives to this option. Low mass, high efficiency solar power systems have the potential for use at low outer planetary temperatures

James Fincannon

2008-01-01

389

Exploration of the Outer Solar System by Stellar Occultations  

E-print Network

Exploration of the Outer Solar System by Stellar Occultations Franc¸oise Roques Æ Yannick Boissel Æ occultations are a powerful method for exploring the outer solar system, where faintness and small angular. Unique kilometric spatial resolutions or better can be reached through that method. Occultations usually

Widemann, Thomas

390

Acute zonal occult outer retinopathy: A case report  

Microsoft Academic Search

BackgroundAcute zonal occult outer retinopathy (AZOOR) is a disorder of unknown etiology with a predilection for young women. AZOOR is characterized by an acute loss of one or more zones of outer retinal function with a corresponding loss of visual field in one or both eyes. Patients present with photopsia, variable funduscopic changes, and abnormal electroretinogram (ERG) findings. There are

Josephine O. Ibironke; Andrew S. Gurwood

2010-01-01

391

RMP Colloquia Sputtering of ices in the outer solar system  

E-print Network

, typically solar-system bodies is water ice. That is, excluding the four giantRMP Colloquia Sputtering of ices in the outer solar system R. E. Johnson Engineering Physics, University of Virginia, Charlottesville, Virginia 22903 Exploration of the outer solar system has led

Johnson, Robert E.

392

Is the outer Solar System chaotic? WAYNE B. HAYES  

E-print Network

LETTERS Is the outer Solar System chaotic? WAYNE B. HAYES Computer Science Department, University. There exists both apparently unassailable evidence that the outer Solar System is chaotic1 development. The Solar System is known to be `practically stable', in the sense that none of the known planets

Loss, Daniel

393

Homesteading and the creation of property rights in outer space  

Microsoft Academic Search

The rapid proliferation of space travel has made the colonization of space and the exploitation of its scarce resources imminent. The development of scarce resources in space has raised serious legal, political and economic questions that must soon be resolved if countries are to coexist peacefully in outer space. This paper examines the problem of defining property rights in outer

Joel D. Scheraga

1986-01-01

394

Spam Zombies from Outer Space John Aycock & Nathan Friess  

E-print Network

Spam Zombies from Outer Space John Aycock & Nathan Friess Department of Computer Science University-mail: {aycock,friessn}@cpsc.ucalgary.ca. Keywords Zombies, botnets, spam, spyware, email worms 15th Annual EICAR Conference "Security in the Mobile and Networked World" - 164 - #12;Spam Zombies from Outer Space Abstract

Aycock, John

395

Newborns' Face Recognition: Role of Inner and Outer Facial Features  

ERIC Educational Resources Information Center

Existing data indicate that newborns are able to recognize individual faces, but little is known about what perceptual cues drive this ability. The current study showed that either the inner or outer features of the face can act as sufficient cues for newborns' face recognition (Experiment 1), but the outer part of the face enjoys an advantage…

Turati, Chiara; Macchi Cassia, Viola; Simion, Francesca; Leo, Irene

2006-01-01

396

Advanced Metal Foam Structures for Outer Space  

NASA Technical Reports Server (NTRS)

A document discusses a proposal to use advanced materials especially bulk metallic glass (BMG) foams in structural components of spacecraft, lunar habitats, and the like. BMG foams, which are already used on Earth in some consumer products, are superior to conventional metal foams: BMG foams have exceptionally low mass densities and high strength-to-weight ratios and are more readily processable into strong, lightweight objects of various sizes and shapes. These and other attractive properties of BMG foams would be exploited, according to the proposal, to enable in situ processing of BMG foams for erecting and repairing panels, shells, containers, and other objects. The in situ processing could include (1) generation of BMG foams inside prefabricated deployable skins that would define the sizes and shapes of the objects thus formed and (2) thermoplastic deformation of BMG foams. Typically, the generation of BMG foams would involve mixtures of precursor chemicals that would be subjected to suitable pressure and temperature schedules. In addition to serving as structural components, objects containing or consisting of BMG foams could perform such functions as thermal management, shielding against radiation, and shielding against hypervelocity impacts of micrometeors and small debris particles.

Hanan, Jay; Johnson, William; Peker, Atakan

2005-01-01

397

Hard diffraction and rapidity gaps  

SciTech Connect

The field of hard diffraction, which studies events with a rapidity gap and a hard scattering, has expanded dramatically recently. A review of new results from CDF, D{O}, H1 and ZEUS will be given. These results include diffractive jet production, deep-inelastic scattering in large rapidity gap events, rapidity gaps between high transverse energy jets, and a search for diffractive W-boson production. The combination of these results gives new insight into the exchanged object, believed to be the pomeron. The results axe consistent with factorization and with a hard pomeron that contains both quarks and gluons. There is also evidence for the exchange of a strongly interacting color singlet in high momentum transfer (36 < {vert_bar}t{vert_bar} < 1000 GeV{sup 2}) events.

Brandt, A.

1995-09-01

398

Foam shell project: Progress report  

SciTech Connect

The authors report on their work to produce a foam shell target for two possible applications: (1) as liquid-layered cryogenic target on Omega Upgrade, and (2) as a back-up design for the NIF. This target consists of a roughly 1 mm diameter and 100 {mu}m thick spherical low-density foam shell surrounding a central void. The foam will be slightly overfilled with liquid D{sub 2} or DT, the overfilled excess being symmetrically distributed on the inside of the shell and supported by thermal gradient techniques. The outside of the foam is overcoated with full density polymer which must be topologically smooth. The technology for manufacturing this style of foam shell involves microencapsulation techniques and has been developed by the Japanese at ILE. Their goal is to determine whether this technology can be successfully adapted to meet US ICF objectives. To this end a program of foam shell development has been initiated at LLNL in collaboration with both the General Atomics DOE Target Fabrication Contract Corporation and the Target Fabrication Group at LLE.

Overturf, G.; Reibold, B.; Cook, B. [Lawrence Livermore National Lab., CA (United States); Schroen-Carey, D. [WJSA (United States)

1994-03-25

399

Ordering of hard spheres inside hard cylindrical pores.  

PubMed

Isothermal-isobaric simulations on the ordering behavior of hard spheres upon confinement are presented. The radii of the confining cylinders go from 1.1 to 2 in units of the diameters of the hard spheres adsorbed. In all the range of pressures considered the spheres were located in concentric layers, as many as the radius of the hard cylinder would permit. When the pressure increases, the hard spheres go from being loosely arranged to the formation of ordered structures. This change is marked in all cases by a distinct break in the density of spheres in a narrow pressure range. When the tube radius is smaller than 1.5, the high-pressure ordering is determined by the number of coplanar spheres you can have within a circle of radius equal to that of the confining tube. For wider tubes, the change upon compression is determined by the formation of defected two-dimensional triangular lattices wrapped to fit inside the particular cylinder we are considering. PMID:19658477

Durán-Olivencia, F J; Gordillo, M C

2009-06-01

400

Hard X-ray latitude effect measured during a transatlantic balloon flight  

SciTech Connect

The hard X-ray latitude effect is reported in the range of McIlwain shell parameter L from 1.4 to 2.6 (earth radius units). The data were obtained with two X-ray scintillator detectors flown on board a transatlantic balloon launched from Trapani, Sicily. The data analysis method for measuring the flux from weak X-ray sources is also described.

Frontera, F. (CNR, Istituto Plasma Spazio, Frascati, Italy); Fuligni, F. (CNR, Istituto di Tecnologie e Studio delle Radiazioni Extraterrestri, Bologna, Italy)

1981-01-01

401

Pyrocarbon-coating on powdery hard-carbon using chemical vapor infiltration and its electrochemical characteristics  

Microsoft Academic Search

Using the pressure-pulsed chemical vapor infiltration technique, thin pyrocarbon films were coated on the surface of the hard-carbon particles. The crystallinity of pyrocarbon shell was higher than that of the core carbon. The BET surface area and the pores with the diameter of 1.5–5nm were extremely decreased after coating with 7wt.% pyrocarbon. These changes in the nano-scaled structure of carbon

Yoshimi Ohzawa; Yasuyuki Yamanaka; Kazuhisa Naga; Tsuyoshi Nakajima

2005-01-01

402

Comparison between gamma and beta irradiation effects on hydroxypropylmethylcellulose and gelatin hard capsules  

Microsoft Academic Search

The effects of electron beam or ?-irradiation on technological performances (capsule hardness, expressed as deforming work\\u000a and dissolution time) of empty 2-shell capsules made of gelatin or hydroxypropylmethylcellulose (HPMC) were studied. Capsule\\u000a structural changes induced by radiation treatment were investigated by capillary viscometry and atomic force microscopy (AFM).\\u000a The capsules were irradiated in the air at 5, 15, and 25

Francesco Cilurzo; Francesca Selmin; Paola Minghetti; Luisa Montanari; Cristina Lenardi; Francesco Orsini; Giulio Poletti

2005-01-01

403

Hard diffraction -- 20 years later  

E-print Network

The idea of diffractive processes with a hard scale involved, to resolve the underlying parton dynamics, was published 1985 and experimentally verified 1988. Today hard diffraction is an active research field with high-quality data and new theoretical models. The trend from Regge-based pomeron models to QCD-based parton level models has given insights on QCD dynamics involving perturbative gluon exchange mechanisms, including the predicted BFKL-dynamics, as well as novel ideas on non-perturbative colour fields and their interactions. Extrapolations to the LHC include the interesting possibility of diffractive Higgs production.

Gunnar Ingelman

2005-12-12

404

Hardness of ion implanted ceramics  

SciTech Connect

It has been established that the wear behavior of ceramic materials can be modified through ion implantation. Studies have been done to characterize the effect of implantation on the structure and composition of ceramic surfaces. To understand how these changes affect the wear properties of the ceramic, other mechanical properties must be measured. To accomplish this, a commercially available ultra low load hardness tester has been used to characterize Al/sub 2/O/sub 3/ with different implanted species and doses. The hardness of the base material is compared with the highly damaged crystalline state as well as the amorphous material.

Oliver, W.C.; McHargue, C.J.; Farlow, G.C.; White, C.W.

1985-01-01

405

Evaluation of procedures for outer membrane isolation from Campylobacter jejuni  

PubMed Central

Although infection with Campylobacter jejuni is one of the leading causes of gastroenteritis worldwide, relatively little is known about the factors that are required to elicit a protective immune response. The need for a vaccine against this pathogen is well recognized and a number of vaccine candidates have been tested with varying degrees of success; however, there is still a lack of a suitable vaccine. To gain a better understanding of the outer-membrane protein components of this organism, a ‘gold standard’ method to purify the outer membrane is needed. Therefore, we attempted to develop a robust and reliable method which resulted in a pure outer-membrane fraction. A total of nine methodologies were examined and analysed by SDS-PAGE and immunoblotting using subcellular markers for the cytoplasm, cytoplasmic membrane and outer membrane. We found that glycine extraction, differential detergent extraction using Triton X-100, serial extraction using 1 M Tris pH 7, spheroplasting by lysozyme and sonication, and carbonate extraction did not produce pure outer-membrane preparations. However, we identified three methods that provided outer-membrane fractions free from subcellular contamination. Isopycnic centrifugation using a 30–60 % sucrose gradient produced seven fractions free from cytoplasmic or cytoplasmic membrane contamination; however, these fractions did not correspond as well as expected with the typical outer-membrane-associated peak (e.g. Escherichia coli or Salmonella). The spheroplast method using lysozyme alone also resulted in pure outer-membrane fraction, as did carbonate washing of this sample. The extraction of outer membranes using N-lauroylsarcosine (Sarkosyl) produced the purest and most reproducible sample. These outer-membrane preparations will be useful for future studies aimed at identifying C. jejuni surface proteins as vaccine components. PMID:19246768

Hobb, Rhonda I.; Fields, Joshua A.; Burns, Christopher M.; Thompson, Stuart A.

2009-01-01

406

Outer Retinal Structure in Patients with Acute Zonal Occult Outer Retinopathy  

PubMed Central

Purpose To correlate visual function with high-resolution images of retinal structure using adaptive optics scanning laser ophthalmoscopy (AOSLO) in 4 patients with acute zonal occult outer retinopathy (AZOOR). Design Observational case series. Methods Four women, aged 18–51, with acute focal loss of visual field or visual acuity, photopsia, and minimal funduscopic changes were studied with best-corrected visual acuity (BCVA), Goldmann kinetic and automated perimetry and fundus-guided microperimetry, full-field and multifocal electroretinography (ffERG and mfERG), spectral domain optical coherence tomography (SDOCT) and AOSLO imaging. Cone spacing was measured in four eyes and compared with 27 age-similar normal eyes. Additional functional testing in one patient suggested that cones were absent but rods remained. Serum from all patients was analyzed for anti-retinal antibody activity. Results In all patients vision loss was initially progressive, then stable. Symptoms were unilateral in 2 and bilateral but asymmetric in 2 patients. In each patient, loss of retinal function correlated with structural changes in the outer retina. AOSLO showed focal cone loss in most patients, although in one patient with central vision loss such change was absent. In another patient, structural and functional analyses suggested that cones had degenerated but rods remained. Anti-retinal antibody activity against a ~45kd antigen was detected in 1 of the patients; the other 3 patients showed no evidence of abnormal anti-retinal antibodies. Conclusions Focal abnormalities of retinal structure correlated with vision loss in patients with AZOOR. High-resolution imaging can localize and demonstrate the extent of outer retinal abnormality in AZOOR patients. PMID:22105799

Mkrtchyan, Marianna; Lujan, Brandon J.; Merino, David; Thirkill, Charles E.; Roorda, Austin; Duncan, Jacque L.

2011-01-01

407

Biology of the hard clam Hard clams of the genus Mercenaria  

E-print Network

Biology of the hard clam Hard clams of the genus Mercenaria are found from the Gulf of St. Lawrence of the general- izations may apply to all hard clams. The hard clam is rarely found where salinities average less than 20 parts per thousand (ppt). Hard clams occu- py intertidal and subtidal habitats, where

Florida, University of

408

Dynamic indentation hardness of materials  

NASA Astrophysics Data System (ADS)

Indentation hardness is one of the simplest and most commonly used measures for quickly characterizing material response under static loads. Hardness may mean resistance to cutting to a machinist, resistance to wear to a tribologist, or a measure of flow stress to a design engineer. In this simple technique, a predetermined force is applied to an indenter for 5-30 seconds causing it to penetrate a specimen. By measuring the load and the indentation size, a hardness value is determined. However, the rate of deformation during indenter penetration is of the order of 10sp{-4}\\ ssp{-1}. In most practical applications, such as high speed machining or impact, material deforms at strain rates in excess of 10sp3{-}10sp5\\ ssp{-1}. At such high rates, it is well established that the plastic behavior of materials is considerably different from their static counterpart. For example, materials exhibit an increase in their yield stress, flow stress, fracture stress, and fracture toughness at high strain rates. Hence, the use of static hardness as an indicator of material response under dynamic loads may not be appropriate. Accordingly, a simple dynamic indentation hardness tester is developed for characterizing materials at strain rates similar to those encountered in realistic situations. The experimental technique uses elastic stress wave propagation phenomena in a slender rod. The technique is designed to deliver a single indentation load of 100-200 mus duration. Similar to static measurements, the dynamic hardness is determined from the measured load and indentation size. Hardness measurements on a range of metals have revealed that the dynamic hardness is consistently greater than the static hardness. The increase in hardness is strongly dependent on the crystal structure of the material. The observed trends in hardness are also found to be consistent with the yield and flow stresses of these materials under uniaxial compression. Therefore, it is suggested that the current technique can be used to assess the rate sensitive nature of engineering materials. To further characterize the plastic strains within the indentation volume, static microhardness measurements were also performed within this region. The contours of microhardness indicated that the plastic zone beneath the indenter is typically smaller under dynamic conditions compared to static loading for rate sensitive materials. To assess the influence of the elastic modulus, yield stress, and work hardening coefficient on the induced plastic volume, finite element simulations were performed using the explicit finite element code LS-DYNA3D. The parametric study revealed that the yield stress has the most significant influence on the size and shape of the plastic zone. The above microstructural and numerical results can be used as guidelines for proper selection and design of engineering materials in applications involving high strain rate loading. Moreover, the contours of microhardness variation can be used to verify the suitability of analytical models developed for characterizing the deformation behavior of engineering materials under complex three dimensional loads.

Koeppel, Brian James

409

Shell model Monte Carlo methods  

SciTech Connect

We review quantum Monte Carlo methods for dealing with large shell model problems. These methods reduce the imaginary-time many-body evolution operator to a coherent superposition of one-body evolutions in fluctuating one-body fields; resultant path integral is evaluated stochastically. We first discuss the motivation, formalism, and implementation of such Shell Model Monte Carlo methods. There then follows a sampler of results and insights obtained from a number of applications. These include the ground state and thermal properties of pf-shell nuclei, thermal behavior of {gamma}-soft nuclei, and calculation of double beta-decay matrix elements. Finally, prospects for further progress in such calculations are discussed. 87 refs.

Koonin, S.E. [California Inst. of Tech., Pasadena, CA (United States). W.K. Kellogg Radiation Lab.; Dean, D.J. [Oak Ridge National Lab., TN (United States)

1996-10-01

410

Bathymetry and acoustic backscatter-outer mainland shelf, eastern Santa Barbara Channel, California  

USGS Publications Warehouse

In 2010 and 2011, scientists from the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), acquired bathymetry and acoustic-backscatter data from the outer shelf region of the eastern Santa Barbara Channel, California. These surveys were conducted in cooperation with the Bureau of Ocean Energy Management (BOEM). BOEM is interested in maps of hard-bottom substrates, particularly natural outcrops that support reef communities in areas near oil and gas extraction activity. The surveys were conducted using the USGS R/V Parke Snavely, outfitted with an interferometric sidescan sonar for swath mapping and real-time kinematic navigation equipment. This report provides the bathymetry and backscatter data acquired during these surveys in several formats, a summary of the mapping mission, maps of bathymetry and backscatter, and Federal Geographic Data Committee (FGDC) metadata.

Dartnell, Peter; Finlayson, David P.; Ritchie, Andrew C.; Cochrane, Guy R.; Erdey, Mercedes D.

2012-01-01

411

The HI shell G132.6-0.7-25.3: A Supernova Remnant or an Old Wind-Blown Bubble?  

E-print Network

Data from the Canadian Galactic Plane Survey reveal an abundance of HI shells and arcs in the disk of our galaxy. While their shape is suggestive of stellar winds or supernovae influence, very few of these structures have been examined in detail thus far. A fine example is an HI shell in the outer Galaxy with no continuum counterpart discovered in the survey's pilot project. Its size and kinematics suggest that it was created by the winds of a single late-type O star which has since evolved off the main sequence or by a supernova explosion. A B1 Ia star at the centre of the shell, in projection, is a possible candidate for energy source if the shell is assumed to be wind-blown. The shell's shape implies a surprisingly small scale height of less than about 30 pc for the surrounding gas if the elongation is due to evolution in a density gradient.

Magdalen Normandeau; A. R. Taylor; P. E. Dewdney; Shantanu Basu

2000-02-23

412

Magnetic dipole moment of a spherical shell with TRM acquired in a field of internal origin. [Thermoremanent Magnetization implications for lunar magnetic field  

NASA Technical Reports Server (NTRS)

The acquisition of thermoremanent magnetization (TRM) by a cooling spherical shell is studied for internal magnetizing dipole fields, using Runcorn's (1975) theorems on magnetostatics. If the shell cools progressively inward, inner regions acquire TRM in a net field composed of the dipole source term plus a uniform field due to the outer magnetized layers. In this case, the global dipole moment and external remanent field are nonzero when the whole shell has cooled below the Curie point and the source dipole has disappeared. The remanent field outside the shell is found to depend on the thickness, radii, and cooling rate of the shell, as well as the coefficient of TRM and the intensity of the magnetizing field. Some implications for the moon's remanent dipole moment are discussed.

Srnka, L. J.

1976-01-01

413

Shell may expand detergent alcohols  

SciTech Connect

Shell Chemical is studying plans to expand detergent alcohols capacity in the US, CW has learned. The company is considering adding capacity for about 80 million lbs/year. If the project is approved, it would be implemented at the company`s Geismar, LA site. Shell will make a final decision on whether to proceed with the project within six months. It has been rumored to be considering a capacity addition as a result of tightening supply of natural and synthetic detergent alcohols.

NONE

1996-10-23

414

A Charged Rotating Cylindrical Shell  

NASA Astrophysics Data System (ADS)

We give an example of a spacetime having an infinite thin rotating cylindrical shell constituted by a charged perfect fluid as a source. As the interior of the shell the Bonnor-Melvin universe is considered, while its exterior is represented by the Datta-Raychaudhuri spacetime. We discuss the energy conditions and we show that our spacetime contains closed timelike curves. Trajectories of charged test particles both inside and outside the cylinder are also examined. An expression for the angular velocity of a circular motion inside the cylinder is given.

Geršl, J.; Klepá?, P.; Horský, J.

2004-06-01

415

Dual shell pressure balanced vessel  

DOEpatents

A dual-wall pressure balanced vessel for processing high viscosity slurries at high temperatures and pressures having an outer pressure vessel and an inner vessel with an annular space between the vessels pressurized at a pressure slightly less than or equivalent to the pressure within the inner vessel.

Fassbender, Alexander G. (West Richland, WA)

1992-01-01

416

FATIGUE OF BIOMATERIALS: HARD TISSUES.  

PubMed

The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions. PMID:20563239

Arola, D; Bajaj, D; Ivancik, J; Majd, H; Zhang, D

2010-09-01

417

Playing the Numbers: Hard Choices  

ERIC Educational Resources Information Center

Stateline.org recently called this recession the worst in 50 years for state budgets. As has been the case in past economic downturns, higher education looks to be particularly hard hit. Funds from the American Recovery and Relief Act may have postponed some of the difficulty for many colleges and universities, but the outlook for public higher…

Doyle, William R.

2009-01-01

418

Materials science Nanotubes get hard  

E-print Network

Materials science Nanotubes get hard under pressure Proc. Natl Acad. Sci. USA doi:10.1073/pnas.0405877101 (2004) When Zhongwu Wang et al. squeezed carbon nanotubes in a diamond anvil cell, they made nanotubes into diamond itself: the carbon material formed under compression at room temperature seems

Downs, Robert T.

419

Is Carbon Hard or Soft?  

NSDL National Science Digital Library

The representation shows differences in the arrangement of carbon atoms that make up diamonds and graphite. Through text and pictures, the resource describes the difference in arrangement of two different carbon allotropes. The text relates the differences in arrangements to differences in the hardness (properties) of the materials.

420

Hard electroproduction of vector mesons  

E-print Network

It is reported on a global analysis of hard vector-meson electroproduction which is based on the handbag factorization. The generalized parton distributions are constructed from their forward limits with the help of double distributions and the partonic subprocesses are calculated within the modified perturbative approach.

P. Kroll

2008-06-16

421

Suzaku Detection of Diffuse Hard X-Ray Emission Outside Vela X  

NASA Technical Reports Server (NTRS)

Vela X is a large, 3 deg x 2 deg, radio-emitting pulsar wind nebula (PWN) powered by the Vela pulsar in the Vela supernova remnant. Using four Suzaku/XIS observations pointed just outside Vela X, we find hard X-ray emission extending throughout the fields of view. The hard X-ray spectra are well represented by a power-law. The photon index is measured to be constant at Gamma approximates 2.4, similar to that of the southern outer part of Vela X. The power-law flux decreases with increasing distance from the pulsar. These properties lead us to propose that the hard X-ray emission is associated with the Vela PWN. The larger X-ray extension found in this work strongly suggests that distinct populations relativistic electrons form the X-ray PWN and Vela X, as was recently inferred from multiwavelength spectral modeling of Vela X.

Katsuda, Satoru; Mori, Koji; Petre, Robert; Yamaguchi, Hiroya; Tsunemi, Hiroshi; Bocchino, Fabrizio; Bamba, Aya; Miceli, Marco; Hewitt, John W.; Temim, Tea; Uchida, Hiroyuki; Yoshii, Rie

2011-01-01

422

Fabrication of core–shell hybrid nanoparticles by mineralization on poly(?-caprolactone)- b -poly(methacrylic acid) copolymer micelles  

Microsoft Academic Search

Polymer micelles containing calcium phosphate (CaP) minerals on the shell domain were developed by nanotemplate-driven mineralization.\\u000a The polymer micelle nanotemplate was prepared by self-assembly of a poly(?-caprolactone)-b-poly(methacrylic acid) (PCL-b-PMAA) copolymer. PMAA formed the anionic outer shell, and PCL constructed the hydrophobic inner core. Subsequent addition\\u000a of calcium and phosphate ions to micellar solutions induced CaP mineral deposition within the PMAA

Hong Jae Lee; Sang Cheon Lee

2010-01-01

423

Carbon in the outer solar system  

NASA Technical Reports Server (NTRS)

The satellites of Uranus, with densities between 1.3 and 1.7 g cm(-3) (from Voyager 2 observations) and the Pluto-Charon system, with a mean density of just above 1.8 g cm(-3) (from terrestrial observations of mutual eclipse events), are too dense to have a significant amount of methane ice in their interiors. However, the observed densities do not preclude contributions from such organic materials as the acid-insoluble residue in carbonaceous chondrites and laboratory-produced tholins, which have densities on the order of approximately 1.5 g cm(-3). These and other considerations have led researchers to investigate the carbon mass budget in the outer solar system, with an emphasis on understanding the contribution of organic materials. Modeling of the interiors of Pluto and Charon (being carried out by R. Reynolds and A. Summers of NASA/Ames), assuming rock and water ice as the only constituents, suggests a silicate mass fraction for this system on the order of 0.65 to 0.70. The present work includes the most recent estimates of the C/H enhancements and high z/low z ratios of the giant planets (Pollack and Bodenheimer, 1987), and involves a more careful estimation of the high z/low z mass ratio expected from solar abundances than was used in Pollack et al. (1986), including the influence of the fraction of C in CO on the amount of condensed water ice. These calculations indicate that for a particular fraction of C in CO and a given fraction of C-bearing planetesimals that dissolve in the envelope (most likely in the range 0.50 to 0.75), (1) Jupiter and Saturn require a larger fraction of C in condensed materials than Uranus and Neptune, but (2) the Jupiter and Saturn results are much less strongly constrained by the error bars on the observed C/H enhancements and high z/low z ratios than is the case for Uranus and Neptune. The clearest result is that in the region of the solar nebula near Uranus and Neptune, the minority of carbon that is not in gaseous CO (1) must include a nonzero amount of condensed material, but (2) is most likely not condensed material alone, i.e., there must be a third carbon-bearing component besides condensed material and gaseous CO. Given the implied dearth of methane ice, the condensed carbon is likely dominated by organic material, and the third component present in addition to CO and organics is assumed to be CH4 gas.

Simonelli, D. P.; Pollack, J. B.; Mckay, C. P.

1990-01-01

424

Outer packet sets and feature prediction of computer virus  

NASA Astrophysics Data System (ADS)

The packet sets model was proposed by Prof. Shi in 2008. A packet sets is a set pair composed of internal and outer packet sets, and it has dynamic characteristic. Using packet sets theory, this paper gives the feature prediction of computer virus based on outer packet sets. The concept of virus screening-filtering is given, furthermore, the virus screening-filtering order theorem, composite virus screening-filtering theorem and virus screening-filtering rule are presented. A prediction method of computer virus feature is given based on the results. The outer packet sets is a new tool in the research of the prediction of dynamic virus feature.

Zhang, Ling

2014-10-01

425

Radioisotope Reduction Using Solar Power for Outer Planetary Missions  

NASA Technical Reports Server (NTRS)

Radioisotope power systems have historically been (and still are) the power system of choice from a mass and size perspective for outer planetary missions. High demand for and limited availability of radioisotope fuel has made it necessary to investigate alternatives to this option. Low mass, high efficiency solar power systems have the potential for use at low outer planetary temperatures and illumination levels. This paper documents the impacts of using solar power systems instead of radioisotope power for all or part of the power needs of outer planetary spacecraft and illustrates the potential fuel savings of such an approach.

Fincannon, James

2008-01-01

426

Self-sterilization of bodies during outer planet entry  

NASA Technical Reports Server (NTRS)

A body encountering the atmosphere of an outer planet is subjected to heat loads which could result in high temperature conditions that render terrestrial organisms on or within the body nonviable. To determine whether an irregularly shaped entering body, consisting of several different materials, would be sterilized during inadvertent entry at high velocity, the thermal response of a typical outer planet spacecraft instrument was studied. The results indicate that the Teflon insulated cable and electronic circuit boards may not experience sterilizing temperatures during a Jupiter, Saturn, or Titan entry. Another conclusion of the study is that small plastic particles entering Saturn from outer space have wider survival corridors than do those at Jupiter.

Hoffman, A. R.; Jaworski, W.; Taylor, D. M.

1974-01-01

427

Effects of shell morphology on mechanics of zebra and quagga mussel locomotion.  

PubMed

Although zebra mussels (Dreissena polymorpha) initially colonized shallow habitats within the North American Great Lakes, quagga mussels (Dreissena bugensis) are becoming dominant in both shallow- and deep-water habitats. Shell morphology differs among zebra, shallow quagga and deep quagga mussels but functional consequences of such differences are unknown. We examined effects of shell morphology on locomotion for the three morphotypes on hard (typical of shallow habitats) and soft (characteristic of deep habitats) sedimentary substrates. We quantified morphology using the polar moment of inertia, a parameter used in calculating kinetic energy that describes shell area distribution and resistance to rotation. We quantified mussel locomotion by determining the ratio of rotational (K(rot)) to translational kinetic energy (K(trans)). On hard substrate, K(rot):K(trans) of deep quagga mussels was fourfold greater than for the other morphotypes, indicating greater energy expenditure in rotation relative to translation. On soft substrate, K(rot):K(trans) of deep quagga mussels was approximately one-third of that on hard substrate, indicating lower energy expenditure in rotation on soft substrate. Overall, our study demonstrates that shell morphology correlates with differences in locomotion (i.e. K(rot):K(trans)) among morphotypes. Although deep quagga mussels were similar to zebra and shallow quagga mussels in terms of energy expenditure on sedimentary substrate, their morphology was energetically maladaptive for linear movement on hard substrate. As quagga mussels can possess two distinct morphotypes (i.e. shallow and deep morphs), they might more effectively utilize a broader range of substrates than zebra mussels, potentially enhancing their ability to colonize a wider range of habitats. PMID:21653816

Peyer, Suzanne M; Hermanson, John C; Lee, Carol Eunmi

2011-07-01

428

Tuning structure and mobility of solvation shells surrounding tracer additives.  

PubMed

Molecular dynamics simulations and a stochastic Fokker-Planck equation based approach are used to illuminate how position-dependent solvent mobility near one or more tracer particle(s) is affected when tracer-solvent interactions are rationally modified to affect corresponding solvation structure. For tracers in a dense hard-sphere fluid, we compare two types of tracer-solvent interactions: (1) a hard-sphere-like interaction, and (2) a soft repulsion extending beyond the hard core designed via statistical mechanical theory to enhance tracer mobility at infinite dilution by suppressing coordination-shell structure [Carmer et al., Soft Matter 8, 4083-4089 (2012)]. For the latter case, we show that the mobility of surrounding solvent particles is also increased by addition of the soft repulsive interaction, which helps to rationalize the mechanism underlying the tracer's enhanced diffusivity. However, if multiple tracer surfaces are in closer proximity (as at higher tracer concentrations), similar interactions that disrupt local solvation structure instead suppress the position-dependent solvent dynamics. PMID:25833590

Carmer, James; Jain, Avni; Bollinger, Jonathan A; van Swol, Frank; Truskett, Thomas M

2015-03-28

429

Tuning structure and mobility of solvation shells surrounding tracer additives  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations and a stochastic Fokker-Planck equation based approach are used to illuminate how position-dependent solvent mobility near one or more tracer particle(s) is affected when tracer-solvent interactions are rationally modified to affect corresponding solvation structure. For tracers in a dense hard-sphere fluid, we compare two types of tracer-solvent interactions: (1) a hard-sphere-like interaction, and (2) a soft repulsion extending beyond the hard core designed via statistical mechanical theory to enhance tracer mobility at infinite dilution by suppressing coordination-shell structure [Carmer et al., Soft Matter 8, 4083-4089 (2012)]. For the latter case, we show that the mobility of surrounding solvent particles is also increased by addition of the soft repulsive interaction, which helps to rationalize the mechanism underlying the tracer's enhanced diffusivity. However, if multiple tracer surfaces are in closer proximity (as at higher tracer concentrations), similar interactions that disrupt local solvation structure instead suppress the position-dependent solvent dynamics.

Carmer, James; Jain, Avni; Bollinger, Jonathan A.; van Swol, Frank; Truskett, Thomas M.

2015-03-01

430

Past and future of grid shell structures  

E-print Network

Because of their original organic shape and the column free space that they provide, the design of grid shell structures challenges architects and structural engineers in more than one way. Very few grid shell building ...

Paoli, Céline (Céline Aude)

2007-01-01

431

NOTE / NOTE Comparison between shell morphology and  

E-print Network

NOTE / NOTE Comparison between shell morphology and genetic diversity in two sympatric lymnaeid with shell characteristics common to both species are O. glabra. We also note an absence of hybridization

Roche, Benjamin

432

21 CFR 886.3800 - Scleral shell.  

Code of Federal Regulations, 2014 CFR

...FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3800 Scleral shell. (a) Identification. A scleral shell is a device made of glass or...

2014-04-01

433

Method and apparatus for an inflatable shell  

NASA Technical Reports Server (NTRS)

A method of assembling an inflatable shell of a structure comprises folding a plurality of shell sections about a set of fold lines and integrating the plurality of shell sections together with one another to form the shell. In another embodiment, an inflatable shell comprises a plurality of shell sections, each shell section having two pairs of fold lines for folding into stowage comprising a first gore section having a plurality of first gore panels layered and collectively folded about at a first set of fold lines. Each layer of the first gore panels and second gore panels are configured such that, once the first gore panel and second gore panel are attached to one another at the respective side edges of each panel, the lines of attachment forming a second set of fold lines for the shell section. A system and method for fabricating gore panels is also disclosed.

Johnson, Christopher J. (Inventor)

2012-01-01

434

Anadara grandis - Shell Valve Internal View  

USGS Multimedia Gallery

Anadara grandis seashell, internal view, with scars of the anterior and posterior adductor muscles. The shell has El Rosario, Coxiguina, written in the interior of the shell. Photograph taken 2002 or earlier....

435

Shell Games: Uncovering Periodic Properties.  

ERIC Educational Resources Information Center

Describes activities (demonstrations/experiments) used to introduce history of periodic properties--without electrons, orbitals, filling shells, or any conception of atoms beyond Dalton's model. Activities supplement first chapter in a currently available chemistry text. Indicates potential danger of experiments if proper safety precautions are…

Lamb, William G.

1983-01-01

436

Shell structures for biogas plants  

SciTech Connect

The shell structures designed for biogas plants of the fixed-dome type by the Bremen Overseas Research and Development Association are described. Biogas digesters of the design described have been successfully tested in Rwanda and India without structural or contractural problems.

Sasse, L.

1982-01-01

437

The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution  

E-print Network

Hydro-dynamical modeling of the inner Galaxy suggest that the radius of the outer Lindblad resonance (OLR) of the Galactic bar lies in the vicinity of the Sun. How does this resonance affect the distribution function in the outer parts of a barred disk, and can we identify any effect of the resonance in the velocity distribution f(v) actually observed in the solar neighborhood? To answer these questions, detailed simulations of f(v) in the outer parts of an exponential stellar disks with nearly flat rotation curves and a rotating central bar have been performed. For a model resembling the old stellar disk, the OLR causes a distinct feature in f(v) over a significant fraction of the outer disk. For positions <2kpc outside the OLR radius and at bar angles of \\~10-70 degrees, f(v) inhibits a bi-modality between the low-velocity stars moving like the local standard of rest (LSR) and a secondary mode of stars predominantly moving outward and rotating more slowly than the LSR. Such a bi-modality is indeed present in f(v) inferred from the Hipparcos data for late-type stars in the solar neighborhood. If one interpretes this observed bi-modality as induced by the OLR -- and there are hardly any viable alternatives -- then one is forced to deduce that the OLR radius is slightly smaller than Ro. Moreover, by a quantitative comparison of the observed with the simulated distributions one finds that the pattern speed of the bar is 1.85+/-0.15 times the local circular frequency, where the error is dominated by the uncertainty in bar angle and local circular speed. Also other, less prominent but still significant, features in the observed f(v) resemble properties of the simulated velocity distributions, in particular a ripple caused by orbits trapped in the outer 1:1 resonance.

Walter Dehnen

1999-11-10

438

Shell model description of odd sulfur isotopes  

E-print Network

The low energy structure of $^{35,37,39,41}$S isotopes is described performing shell model calculations with the recently devised SDPF-U interaction. Protons and neutrons are restricted to the $sd$-shell for $N 20$. Natural parity states are described with only in-shell mixing, opposite parity states with 1p-1h inter-shell neutron excitations. Energy levels and intensities of electromagnetic transitions are compared with experimental data when available.

P. C. Srivastava; Jorge G. Hirsch; M. J. Ermamatov; V. K. B. Kota

2012-07-23

439

Control of the Helicity Content of a Gun-Generated Spheromak by Incorporating a Conducting Shell into a Magnetized Coaxial Plasma Gun  

NASA Astrophysics Data System (ADS)

In the formation of magnetized plasmoid by a magnetized coaxial plasma gun (MCPG), the magnetic helicity content of the generated plasmoid is one of the critical parameters. Typically, the bias coil to generate a poloidal flux is mounted either on the outer electrode or inside the inner electrode. However, most of the flux generated in the conventional method spreads even radially outside of the formation region. Thus, only a fraction of the total magnetic flux is actually exploited for helicity generation in the plasmoid. In the proposed system, the plasma gun incorporates a copper shell mounted on the outer electrode. By changing the rise time of the discharge bias coil current and the geometrical structure of the shell, the magnetic field structure and its time evolution can be controlled. The effect of the copper shell has been numerically simulated for the actual gun structure, and experimentally confirmed. This may increase the magnetic helicity content results, through increased poloidal magnetic field.

Matsumoto, Tadafumi; Sekiguchi, Jun'ichi; Asai, Tomohiko

440

Surface-enhanced Raman spectroscopy of double-shell hollow nanoparticles: electromagnetic and chemical enhancements.  

PubMed

Enhancements of the Raman signal by the newly prepared gold-palladium and gold-platinum double-shell hollow nanoparticles were examined and compared with those using gold nanocages (AuNCs). The surface-enhanced Raman spectra (SERS) of thiophenol adsorbed on the surface of AuNCs assembled into a Langmuir-Blodgett monolayer were 10-fold stronger than AuNCs with an inner Pt or Pd shell. The chemical and electromagnetic enhancement mechanisms for these hollow nanoparticles were further proved by comparing the Raman enhancement of nitrothiophenol and nitrotoulene. Nitrothiophenol binds to the surface of the nanoparticles by covalent interaction, and Raman enhancement by both the two mechanisms is possible, while nitrotoulene does not form any chemical bond with the surface of the nanoparticles and hence no chemical enhancement is expected. Based on discrete dipole approximation (DDA) calculations and the experimental SERS results, AuNCs introduced a high electromagnetic enhancement, while the nanocages with inner Pt or Pd shell have a strong chemical enhancement. The optical measurements of the localized surface plasmon resonance (LSPR) of the nanocages with an outer Au shell and an inner Pt or Pd shell were found, experimentally and theoretically, to be broad compared with AuNCs. The possible reason could be due to the decrease of the coherence time of Au oscillated free electrons and fast damping of the plasmon energy. This agreed well with the fact that a Pt or Pd inner nanoshell decreases the electromagnetic field of the outer Au nanoshell while increasing the SERS chemical enhancement. PMID:23647422

Mahmoud, Mahmoud A

2013-05-28

441

Shell side CFD analysis of a small shell-and-tube heat exchanger  

Microsoft Academic Search

The shell side design of a shell-and-tube heat exchanger; in particular the baffle spacing, baffle cut and shell diameter dependencies of the heat transfer coefficient and the pressure drop are investigated by numerically modeling a small heat exchanger. The flow and temperature fields inside the shell are resolved using a commercial CFD package. A set of CFD simulations is performed

Ender Ozden; Ilker Tari

2010-01-01

442

Silica-Metal Core-Shells and Metal Shells Synthesized by Porphyrin-Assisted Photocatalysis  

E-print Network

Silica-Metal Core-Shells and Metal Shells Synthesized by Porphyrin-Assisted Photocatalysis Haorong acid. Magnetic silica-platinum core-shell spheres can also be prepared starting from silica spheres overlayer.11,12 Using uniform core templates such as Sto¨ber silica spheres,19 core-shell metal spheres can

Shelnutt, John A.

443

Insights Into the PA Neutral Atom: from AN Evaluation of PA2+ Outer-Core Correlation Energy Calculations  

NASA Astrophysics Data System (ADS)

Since the identification of f-orbital contribution to the bonding in PaO+, investigations into Pa cations have hoped to characterize as many of the electronic states possible.1 Electronic states of the Pan+ (n=0-4) ions have been investigated using multi-reference spin-orbit configuration interaction (MR-SOCI). Initial investigations using Dunning style correlation consistent double-{?} basis sets are re-examined with a larger triple-{?} basis, with the hope of supporting the order of electronic states. Calculations using Hartree-Fock and CI calculations on the neutral atom did not produce the known order of states. A case study was deemed necessary on similar electron configurations present in the low energy states of Pa2+ more specifically those generated from the 5f26d1 and 5f16d2 configurations. Comparison in the Pa2+ ion is complicated by the lack of experimental results, but the states are presumed to be similar sequence as those in the neutral atom, with the addition of two electrons in the 7s shell. In evaluating the impact of inclusion of the outer core, calculations including valence-outer core correlation were completed for the 5d, 6s, and 6p shells of the Pa2+ ion. The magnitude of these individual shell correlation calculations will allow for identification of the energy level shifts associated with even and odd configurations, better describing the energy order in both the Pa2+ ion case study and for the neutral Pa atom. Upon completion of this aspect of the Pa neutral atom study, the knowledge of the energy levels in the Pan+ (n=0-4) family of ions will be greatly expanded, and may yield a model for future studies of atomic actinide systems. Gibson {et al.} Organometallics 2007, 26, 3947-3956.

Mrozik, Michael K.; Pitzer, Russell M.; Bursten, Bruce E.

2010-06-01

444

Solids of Revolution: The Method of Shells  

NSDL National Science Digital Library

This demo builds a toolbox of teaching aids to illustrate various aspects of volume calculations using the method of shells. Several props are used to demonstrate the geometric ideas of "shells" and the notion of "nesting" of shells to obtain an approximation of the volumes of solids of revolution. A collection of animations is included which can be run on a number of platforms.

Roberts, Lila F.

2002-02-02

445

7 CFR 996.19 - Shelled peanuts.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Shelled peanuts. 996.19 Section 996.19 Agriculture...HANDLING STANDARDS FOR DOMESTIC AND IMPORTED PEANUTS MARKETED IN THE UNITED STATES Definitions § 996.19 Shelled peanuts. Shelled peanuts means the...

2013-01-01

446

7 CFR 996.19 - Shelled peanuts.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Shelled peanuts. 996.19 Section 996.19 Agriculture...HANDLING STANDARDS FOR DOMESTIC AND IMPORTED PEANUTS MARKETED IN THE UNITED STATES Definitions § 996.19 Shelled peanuts. Shelled peanuts means the...

2010-01-01

447

7 CFR 996.19 - Shelled peanuts.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Shelled peanuts. 996.19 Section 996.19 Agriculture...HANDLING STANDARDS FOR DOMESTIC AND IMPORTED PEANUTS MARKETED IN THE UNITED STATES Definitions § 996.19 Shelled peanuts. Shelled peanuts means the...

2012-01-01

448

7 CFR 996.19 - Shelled peanuts.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Shelled peanuts. 996.19 Section 996.19 Agriculture...HANDLING STANDARDS FOR DOMESTIC AND IMPORTED PEANUTS MARKETED IN THE UNITED STATES Definitions § 996.19 Shelled peanuts. Shelled peanuts means the...

2011-01-01

449

7 CFR 996.19 - Shelled peanuts.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Shelled peanuts. 996.19 Section 996.19 Agriculture...HANDLING STANDARDS FOR DOMESTIC AND IMPORTED PEANUTS MARKETED IN THE UNITED STATES Definitions § 996.19 Shelled peanuts. Shelled peanuts means the...

2014-01-01

450

59 FR- Guides for Advertising Shell Homes  

Federal Register 2010, 2011, 2012, 2013, 2014

...Part 230 Guides for Advertising Shell Homes AGENCY: Federal Trade...inhabitable'' than what is a ``shell'' home. Report of interview...panelized roof, installing a wet core (central plumbing, heating...this may be that the term ``shell'' home as it is used by...

1994-09-30

451

Shell Formation and Bone Strength Laying Hens  

E-print Network

-related decline of shell quality. Since the majority of eggshell calcium is absorbed in the duodenum, the dramatic. In the shell gland CA is considered a key enzyme in the supply of the carbonate ions needed for shell formation , plasma membrane calcium ATP-ase. Author's address: Anna Wistedt, Department of Anatomy, Physiology

452

7 CFR 981.6 - Shelled almonds.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Shelled almonds. 981.6 Section 981.6 Agriculture...Nuts), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 981.6 Shelled almonds. Shelled almonds mean raw or...

2010-01-01

453

6. OUTER BLAST DOOR, WEST REAR. Edwards Air Force ...  

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

6. OUTER BLAST DOOR, WEST REAR. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

454

Outer hair cell piezoelectricity: Frequency response enhancement and resonance behavior  

PubMed Central

Stretching or compressing an outer hair cell alters its membrane potential and, conversely, changing the electrical potential alters its length. This bi-directional energy conversion takes place in the cell’s lateral wall and resembles the direct and converse piezoelectric effects both qualitatively and quantitatively. A piezoelectric model of the lateral wall has been developed that is based on the electrical and material parameters of the lateral wall. An equivalent circuit for the outer hair cell that includes piezoelectricity shows a greater admittance at high frequencies than one containing only membrane resistance and capacitance. The model also predicts resonance at ultrasonic frequencies that is inversely proportional to cell length. These features suggest all mammals use outer hair cell piezoelectricity to support the high-frequency receptor potentials that drive electromotility. It is also possible that members of some mammalian orders use outer hair cell piezoelectric resonance in detecting species-specific vocalizations. PMID:14514199

Weitzel, Erik K.; Tasker, Ron; Brownell, William E.

2010-01-01

455

Decreasing Outer Hair Cell Membrane Cholesterol Increases Cochlear Electromechanics  

NASA Astrophysics Data System (ADS)

The effect of decreasing membrane cholesterol on the mechanical response of the cochlea to acoustic and/or electrical stimulation was monitored using laser interferometry. In contrast to pharmacological interventions that typically decrease cochlear electromechanics, reducing membrane cholesterol increased the response. The electromechanical response in untreated preparations was asymmetric with greater displacements in response to positive currents and cholesterol depletion increased the asymmetry. The results confirm that outer hair cell electromotility is enhanced by low membrane cholesterol. The asymmetry of the response indicates the outer hair cell resting membrane potential is hyperpolarized relative to the voltage of maximum gain for the outer hair cell voltage-displacement function. The magnitude of the response increase suggests a non-uniform distribution of cholesterol along the lateral wall of normal adult outer hair cells.

Brownell, William E.; Jacob, Stefan; Hakizimana, Pierre; Ulfendahl, Mats; Fridberger, Anders

2011-11-01

456

Assembly of ?-barrel proteins in the mitochondrial outer membrane.  

PubMed

Mitochondria evolved through endosymbiosis of a Gram-negative progenitor with a host cell to generate eukaryotes. Therefore, the outer membrane of mitochondria and Gram-negative bacteria contain pore proteins with ?-barrel topology. After synthesis in the cytosol, ?-barrel precursor proteins are first transported into the mitochondrial intermembrane space. Folding and membrane integration of ?-barrel proteins depend on the mitochondrial sorting and assembly machinery (SAM) located in the outer membrane, which is related to the ?-barrel assembly machinery (BAM) in bacteria. The SAM complex recognizes ?-barrel proteins by a ?-signal in the C-terminal ?-strand that is required to initiate ?-barrel protein insertion into the outer membrane. In addition, the SAM complex is crucial to form membrane contacts with the inner mitochondrial membrane by interacting with the mitochondrial contact site and cristae organizing system (MICOS) and shares a subunit with the endoplasmic reticulum-mitochondria encounter structure (ERMES) that links the outer mitochondrial membrane to the endoplasmic reticulum (ER). PMID:25305573

Höhr, Alexandra I C; Straub, Sebastian P; Warscheid, Bettina; Becker, Thomas; Wiedemann, Nils

2015-01-01

457

49 CFR 192.10 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Outer continental shelf pipelines. 192.10 Section 192.10 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

2013-10-01

458

49 CFR 195.9 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Outer continental shelf pipelines. 195.9 Section 195.9 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF...

2013-10-01

459

49 CFR 192.10 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Outer continental shelf pipelines. 192.10 Section 192.10 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

2011-10-01

460

49 CFR 195.9 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Outer continental shelf pipelines. 195.9 Section 195.9 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF...

2011-10-01

461

49 CFR 192.10 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Outer continental shelf pipelines. 192.10 Section 192.10 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

2010-10-01

462

49 CFR 195.9 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Outer continental shelf pipelines. 195.9 Section 195.9 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF...

2010-10-01

463

49 CFR 195.9 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 false Outer continental shelf pipelines. 195.9 Section 195.9 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF...

2014-10-01

464

49 CFR 192.10 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Outer continental shelf pipelines. 192.10 Section 192.10 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

2012-10-01

465

49 CFR 195.9 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Outer continental shelf pipelines. 195.9 Section 195.9 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF...

2012-10-01

466

49 CFR 192.10 - Outer continental shelf pipelines.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 false Outer continental shelf pipelines. 192.10 Section 192.10 Transportation...Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION...DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL...

2014-10-01

467

Radioisotope Electric Propulsion for Fast Outer Planetary Orbiters  

NASA Technical Reports Server (NTRS)

Recent interest in outer planetary targets by the Office of Space Science has spurred the search for technology options to enable relatively quick missions to outer planetary targets. Several options are being explored including solar electric propelled stages combined with aerocapture at the target and nuclear electric propulsion. Another option uses radioisotope powered electric thrusters to reach the outer planets. Past work looked at using this technology to provide faster flybys. A better use for this technology is for outer planet orbiters. Combined with medium class launch vehicles and a new direct trajectory these small, sub-kilowatt ion thrusters and Stirling radioisotope generators were found to allow missions as fast as 5 to 12 years for objects from Saturn to Pluto, respectively. Key to the development is light spacecraft and science payload technologies.

Oleson, Steven; Benson, Scott; Gefert, Leon; Patterson, Michael; Schreiber, Jeffrey

2002-01-01

468

A Closer Look of the Inner and Outer Planets  

NSDL National Science Digital Library

In this lesson, students will research properties of the inner and outer planets in our Solar System. They will organize their research by creating a Solar System poster that displays a comparison between the planets.

Vanessa Brewster

2012-07-27

469

Electron beam seals outer surfaces of porous bodies  

NASA Technical Reports Server (NTRS)

Porous tungsten plugs provide even airflow for frictionless bearings used in air bearing supported gyros. The plugs have their outer cylindrical surface sealed by an electron beam process to ensure unidirectional airflow through their exit ends.

Herz, W. H.; Kurtz, A. D.; Kurtz, R. A.

1966-01-01

470

Extensions to a nonlinear finite-element axisymmetric shell model based on Reissner's shell theory  

SciTech Connect

Extensions to shell analysis not usually associated with shell theory are described in this paper. These extensions involve thick shells, nonlinear materials, a linear normal stress approximation, and a changing shell thickness. A finite element shell-of-revolution model has been developed to analyze nuclear material shipping containers under severe impact conditions. To establish the limits for this shell model, the basic assumptions used in its development were studied; these are listed in this paper. Several extensions were evident from the study of these limits: a thick shell, a plastic hinge, and a linear normal stress.

Cook, W.A.

1981-01-01

471

K-shell and extreme ultraviolet spectroscopic signatures of structured Ar puff Z-pinch loads with high K-shell x-ray yield  

SciTech Connect

Structured 12-cm-diam Ar gas-puff loads have recently produced Z-pinch implosions with reduced Rayleigh-Taylor instability growth and increased K-shell x-ray yield [H. Sze, J. Banister, B. H. Failor, J. S. Levine, N. Qi, A. L. Velikovich, J. Davis, D. Lojewski, and P. Sincerny, Phys. Rev. Lett. 95, 105001 (2005)]. To better understand the dynamics of these loads, we have measured the extreme ultraviolet (XUV) emission resolved radially, spectrally, and axially. Radial measurements indicated a compressed diameter of {approx_equal}3 mm, consistent with the observed load inductance change and an imploded-mass consisting of a {approx_equal}1.5-mm-diam, hot, K-shell-emitting core and a cooler surrounding blanket. Spectral measurements indicate that, if the load is insufficiently heated, then radiation from the core will rapidly photoheat the outer blanket, producing a strong increase in XUV emission. Also, adding a massive center jet ({>=}20% of load mass) increases the rise and fall times of the XUV emission to {>=}40 ns, consistent with a more adiabatic compression and heating of the load. Axial measurements show that, despite differences in the XUV and K-shell emission time histories, the K-shell x-ray yield is insensitive to axial variations in load mass.

Failor, B. H.; Sze, H. M.; Banister, J. W.; Levine, J. S.; Qi, N.; Apruzese, J. P.; Lojewski, D. Y. [L-3 Communications/Pulse Sciences, San Leandro, California 94577 (United States); Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 (United States); Defense Threat Reduction Agency, Albuquerque, New Mexico 87117 (United States)

2007-02-15

472

Bent-housing turbodrills improve hard-formation directional drilling  

SciTech Connect

Improvements in the design of turbine-powered downhole motors allowed steerable drilling in a hard formation at a high rate of penetration (ROP). Drilling in this dolomite formation with the rotary or with positive-displacement motors (PDMs) was slow during steering operations. Shell's solution to the steering penetration rate problems was to change the well plans if suitable directional drilling tools weren't available. Where possible, the wells were designed with the Zechstein interval drilled as a tangent section with non-steerable turbodrills. However, a better solution was the use of a steerable turbodrill-a tool unavailable on the market at that time. The paper describes motor development, a field test, and the design and operation of the motor.

Koot, L.; Koole, K. (Shell U.K. Exploration and Production, Lowestoft (United Kingdom)); Gaynor, T. (Neyrfor-Weir Ltd., Aberdeen (United Kingdom))

1993-02-15

473

Ultrasonic material hardness depth measurement  

DOEpatents

The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part.

Good, Morris S. (Richland, WA); Schuster, George J. (Kennewick, WA); Skorpik, James R. (Kennewick, WA)

1997-01-01

474

Ultrasonic material hardness depth measurement  

DOEpatents

The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part. 12 figs.

Good, M.S.; Schuster, G.J.; Skorpik, J.R.

1997-07-08

475

Rapidity Gaps in Hard Photoproduction  

E-print Network

Recent results obtained from studies of diffractive processes in hard photoproduction performed by the ZEUS collaboration using data delivered by HERA in 1993 and 1994 are presented. In particular, we have found that $(7 \\pm 3)$\\% of events with two jets at a pseudorapidity interval of 3.5 to 4 are inconsistent with a non-diffractive production mechanism. These events may be interpreted as arising due to the exchange of a colour singlet object of negative squared invariant mass ($-t$) around 40~GeV$^2$. We have also probed the structure of the exchanged colour singlet object in low--$t$ diffractive scattering. By comparing the results from photoproduction and electroproduction processes we find that between 30\\% and 80\\% of the momentum of the exchanged colour singlet object which is carried by partons is due to hard gluons.

L. E. Sinclair

1996-06-18

476

Isolation and characterization of the outer membrane of Borrelia hermsii.  

PubMed

The outer membrane of Borrelia hermsii has been shown by freeze-fracture analysis to contain a low density of membrane-spanning outer membrane proteins which have not yet been isolated or identified. In this study, we report the purification of outer membrane vesicles (OMV) from B. hermsii HS-1 and the subsequent identification of their constituent outer membrane proteins. The B. hermsii outer membranes were released by vigorous vortexing of whole organisms in low-pH, hypotonic citrate buffer and isolated by isopycnic sucrose gradient centrifugation. The isolated OMV exhibited porin activities ranging from 0.2 to 7.2 nS, consistent with their outer membrane origin. Purified OMV were shown to be relatively free of inner membrane contamination by the absence of measurable beta-NADH oxidase activity and the absence of protoplasmic cylinder-associated proteins observed by Coomassie blue staining. Approximately 60 protein spots (some of which are putative isoelectric isomers) with 25 distinct molecular weights were identified as constituents of the OMV enrichment. The majority of these proteins were also shown to be antigenic with sera from B. hermsii-infected mice. Seven of these antigenic proteins were labeled with [3H]palmitate, including the surface-exposed glycerophosphodiester phosphodiesterase, the variable major proteins 7 and 33, and proteins of 15, 17, 38, 42, and 67 kDa, indicating that they are lipoprotein constituents of the outer membrane. In addition, immunoblot analysis of the OMV probed with antiserum to the Borrelia garinii surface-exposed p66/Oms66 porin protein demonstrated the presence of a p66 (Oms66) outer membrane homolog. Treatment of intact B. hermsii with proteinase K resulted in the partial proteolysis of the Oms66/p66 homolog, indicating that it is surface exposed. This identification and characterization of the OMV proteins should aid in further studies of pathogenesis and immunity of tick-borne relapsing fever. PMID:9488399

Shang, E S; Skare, J T; Exner, M M; Blanco, D R; Kagan, B L; Miller, J N; Lovett, M A

1998-03-01

477

STAR FORMATION IN THE OUTER DISK OF SPIRAL GALAXIES  

SciTech Connect

We combine new deep and wide field of view H{alpha} imaging of a sample of eight nearby (d Almost-Equal-To 17 Mpc) spiral galaxies with new and archival H I and CO imaging to study the star formation and the star formation regulation in the outer disk. We find that, in agreement with previous studies, star formation in the outer disk has low covering fractions, and star formation is typically organized into spiral arms. The star formation in the outer disk is at extremely low levels, with typical star formation rate surface densities of {approx}10{sup -5} to 10{sup -6} M{sub Sun} yr{sup -1} kpc{sup -2}. We find that the ratio of the radial extent of detected H II regions to the radius of the H I disk is typically {approx}>85%. This implies that in order to further our understanding of the implications of extended star formation, we must further our understanding of the formation of extended H I disks. We measure the gravitational stability of the gas disk, and find that the outer gaseous disk is typically a factor of {approx}2 times more stable than the inner star-forming disk. We measure the surface density of outer disk H I arms, and find that the disk is closer to gravitational instability along these arms. Therefore, it seems that spiral arms are a necessary, but not sufficient, requirement for star formation in the outer disk. We use an estimation of the flaring of the outer gas disk to illustrate the effect of flaring on the Schmidt power-law index; we find that including flaring increases the agreement between the power-law indices of the inner and outer disks.

Barnes, Kate L.; Van Zee, Liese [Department of Astronomy, Indiana University, Bloomington, IN 47405 (United States); Cote, Stephanie [Canadian Gemini Office, Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria (Canada); Schade, David, E-mail: barneskl@astro.indiana.edu, E-mail: vanzee@astro.indiana.edu, E-mail: Stephanie.Cote@nrc-cnrc.gc.ca, E-mail: David.Schade@nrc-cnrc.gc.ca [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria (Canada)

2012-09-20

478

Isolation and Characterization of the Outer Membrane of Borrelia hermsii  

PubMed Central

The outer membrane of Borrelia hermsii has been shown by freeze-fracture analysis to contain a low density of membrane-spanning outer membrane proteins which have not yet been isolated or identified. In this study, we report the purification of outer membrane vesi