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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

Outer shell structure in nearly zero magnetostrictive amorphous microwires  

NASA Astrophysics Data System (ADS)

Nearly zero magnetostrictive microwires have been proven to be very versatile, due to their extremely soft magnetic properties, the changes in their magnetization mechanism with dimensions, and the appearance of sensitive application-related effects, such as the large Barkhausen and the giant magnetoimpedance effects. Their sensitive magnetoimpedance response originates in the specific domain structure, composed of an inner core and an outer shell (OS), since the OS with a circumferential easy axis is the main region involved in the magnetoimpedance effect. The circumferential OS is believed to display a bamboolike structure with consecutive rings circumferentially magnetized in opposite directions. However, earlier theoretical studies predicted a uniformly magnetized OS as being energetically favored. This paper aims to clarify this contradiction. The variation of the magnetostatic energy from the bamboo domain to the uniformly magnetized state has been calculated and it has been found to be null. Therefore, a uniformly magnetized OS has lower energy due to the absence of domain walls. Calculation results are supported by magneto-optical Kerr effect surface domain images and surface hysteresis loops. For large values of the metallic nucleus diameter, as well as for microwires with the glass coating removed, the OS vanishes, being replaced with a surface region with helical magnetization, which expands toward the microwire surface.

Óvári, T.-A.; Chiriac, H.; Lostun, Mihaela

2009-04-01

3

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

4

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

5

Strong exchange coupling in conventional and inverse ferrimagnetic hard/soft and soft/hard core/shell heterostructured nanoparticles  

NASA Astrophysics Data System (ADS)

Bi-magnetic core/shell nanoparticles are becoming increasingly appealing for diverse fields such as for permanent magnets, microawave absortion, biomedical applications, sensing applications, or future magnetic recording media. Ferrromagnetic (FM)/ antiferromagnetic (AFM) core/shell nanoparticles (or inverted AFM/FM) have been extensively studied. However, exchange coupled hard/soft, or inverse soft/hard, core/shell nanoparticles have been far less investigated. Interestingly, most bi-magnetic core/shell systems are derived by simple partial oxidation of the core, e.g., Co/CoO (FM/AFM) or FePt/Fe3O4 (hard/soft) and only few studies of heterostructured (where core and shell are formed by different magnetic ions) can be found in the literature. We have investigated conventional hard/soft and inverted soft/hard core/shell hetroestructured nanoparticles based on magnetically soft iron oxide (Fe3O4) and magnetically hard manganese oxide (Mn3O4). The core/shell samples were synthesized by seeded growth using either Fe3O4 or Mn3O4 nanoparticles as seeds. Subsequently, thin layers of the complementary material were grown by thermal decomposition of the corresponding metallorganic precursors. The structure characterization (X-ray diffraction and electron diffraction) confirms the presence of cubic (Fe3O4) and tetragonal (Mn3O4) phases both at the bulk and local levels. In addition, high resolution transmission electron microscopy (HR-TEM) with electron energy loss spectroscopy (EELS) mapping confirms the core/shell structure of the nanopartciles. Magnetic characterization and element-selective hysteresis loops obtained by x-ray magnetic circular dichroism (XMCD) reveal a strong exchange coupling between the core and the shell which results in homogeneous loops with moderate coercivity. Moreover, the magnetic properties can be tuned by controlling the core diameter or shell thickness. However, the results depend only weakly on the hard/soft or inverse soft/hard morphology.

Nogues, Josep

2013-03-01

6

Design of small, hard-shell overflow dams on compressible foundations  

Microsoft Academic Search

Considering the peculiarities of small hydropower station construction, the province of Hebei, China, has creatively built a series of hard-shell overflow dams on compressible foundations designed to meet the different geographic and geological characteristics of the sites. Structurally, locally collected stones are used as dam filter; then concrete or reinforced concrete is used to form a hard-shell overflow face slab.

Bingzhao Huang; Shengping Gu

1998-01-01

7

Outer-shell excitation and capture processes: alignment and orientation effects  

NASA Astrophysics Data System (ADS)

This contribution outlines some ongoing activities within a joint programme of experimental and theoretical studies of outer-shell excitation and charge transfer processes in atomic collisions. The main emphasis is presently on alignment and orientation phenomena. The aim is to reveal the shape and dynamics of the electronic charge cloud as it develops in time along the trajectory, and to understand these phenomena in terms of the underlying, basic mechanisms responsible for collisional excitation and transfer.

Andersen, N.; Dowek, D.; Dubois, A.; Hansen, J. P.; Nielsen, S. E.

1990-09-01

8

A Device to Measure Shell Hardness of Dungeness Crabs and Trial Application in the Kodiak Island, Alaska, Commercial Fishery  

Microsoft Academic Search

An objective method of measuring shell hardness of Dungeness crab Cancer magister is necessary because the time elapsed since molting is used in part by fishery managers to set commercial seasons. Limiting the catch of soft-shelled crabs in a fishery is important to decrease mortality from handling and to maintain product quality. We developed a durometer to measure shell hardness

Dave Hicks; B. Alan Johnson

1999-01-01

9

Design of small, hard-shell overflow dams on compressible foundations  

SciTech Connect

Considering the peculiarities of small hydropower station construction, the province of Hebei, China, has creatively built a series of hard-shell overflow dams on compressible foundations designed to meet the different geographic and geological characteristics of the sites. Structurally, locally collected stones are used as dam filter; then concrete or reinforced concrete is used to form a hard-shell overflow face slab. In upstream seepage control design, natural sealing methods are used to replace the artificial upstream blanket designs, in consideration of the river flow condition of high sediment density and high suspended sediment concentration. Based on the riverbed foundation characteristics and the hydrological properties, synthetic energy dissipation methods are used instead of the usual still plunge pool methods to simplify the dam structure and to reduce the construction cost. This is a theoretical study commissioned by the Hebei Bureau of Water Resources on the design of hard-shell overflow dams that have been constructed on compressible foundations. The major technical problems of constructing hard-shell dams on compressible foundations are (a) dam body stability and face slab structure stress analysis; (b) the influence of the settlement of the foundation and dam body on the face slab and the superstructure; (c) downstream energy dissipation and erosion control measures; and (d) seepage damage control measures of the dam body and foundation.

Huang, B.; Gu, S. [Hohai Univ., Nanjing (China). Dept. of Hydropower Engineering

1998-04-01

10

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.

11

Drug release from and mechanical properties of press-coated tablets with hydroxypropylmethylcellulose acetate succinate and plasticizers in the outer shell.  

PubMed

Dissolution profiles of diltiazem hydrochloride (DIL) contained in core tablets from press-coated (PC) tablets with hydroxypropylmethylcellulose acetate succinate (HPMCAS) and plasticizers-adsorbent in the outer shell were investigated. Although, on the addition of triethyl citrate (TEC), triacetin (TA), and acetyltriethy citrate (ATEC) as plasticizers, DIL release was suppressed completely in first fluid (pH 1.2) for 10 h, it was not suppressed in HPMCAS on the addition of dibutyl sebacate (DBS) and acetylated monoglyceride. On the other hand, DIL in second fluid (pH 6.8) was released rapidly after a lag time in all the PC tablets. Water-soluble plasticizers such as TEC, TA, and ATEC showed greater compatibility to HPMCAS, and the results were consistent with suppression of DIL release in first fluid. Furthermore, as to PC tablets with HPMCAS and TEC-adsorbent, the DIL release in second fluid did not change after pretreatment in first fluid by the paddle-beads methods. To evaluate the resistance of the outer shell against such a mechanical impact, tablets with HPMCAS, HPMCAS and TEC- or DBS-adsorbent (H, HT, or HD tablets, respectively) were prepared. In compressive load-strain curves after immersion in first fluid, wet crushing strength was lower in the order of HT > H > HD tablets. Also, the curves of HT tablets at 3 and 21 h after immersion were quite different from those of other tablets, and it was hard to find crushing points. These results suggested that the resistance of the outer shell was due to plastic deformation properties involving some interaction between HPMCAS and TEC. PMID:11292540

Fukui, E; Miyamura, N; Yoneyama, T; Kobayashi, M

2001-04-17

12

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

NASA Astrophysics Data System (ADS)

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 °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.

Shang, Yazhuo; Hu, Jun; Liu, Honglai; Hu, Ying

2010-03-01

13

Hard shell gas-filled contrast enhancement particles for colour Doppler ultrasound imaging of tumors†  

PubMed Central

Hollow hard shell particles of 200 nm and 2 micron diameter with a 10 nm thick porous silica shell have been synthesized using polystyrene templates and a sol–gel process. The template ensures than the hollow particles are monodispersed, while the charged silica surface ensures that they remain suspended in solution for weeks. When filled with perfluorocarbon gas, the particles behave as an efficient contrast agent for colour Doppler ultrasound imaging in human breast tissue. The silica shell provides unique properties compared to conventional soft shell particles employed as ultrasound contrast agents: uniform size control, strong adsorption to tissue and cells immobilizing particles at the tissue injection site, a long imaging lifetime, and a silica surface that can be easily modified with biotargeting ligands or small molecules to adjust the surface charge and polarity. PMID:21841967

Martinez, H. Paul; Kono, Yuko; Blair, Sarah L.; Sandoval, Sergio; Wang-Rodriguez, Jessica

2011-01-01

14

Robust antiferromagnetic coupling in hard-soft bi-magnetic core/shell nanoparticles  

NASA Astrophysics Data System (ADS)

The growing miniaturization demand of magnetic devices is fuelling the recent interest in bi-magnetic nanoparticles as ultimate small components. One of the main goals has been to reproduce practical magnetic properties observed so far in layered systems. In this context, although useful effects such as exchange bias or spring magnets have been demonstrated in core/shell nanoparticles, other interesting key properties for devices remain elusive. Here we show a robust antiferromagnetic (AFM) coupling in core/shell nanoparticles which, in turn, leads to the foremost elucidation of positive exchange bias in bi-magnetic hard-soft systems and the remarkable regulation of the resonance field and amplitude. The AFM coupling in iron oxide—manganese oxide based, soft/hard and hard/soft, core/shell nanoparticles is demonstrated by magnetometry, ferromagnetic resonance and X-ray magnetic circular dichroism. Monte Carlo simulations prove the consistency of the AFM coupling. This unique coupling could give rise to more advanced applications of bi-magnetic core/shell nanoparticles.

Estrader, M.; López-Ortega, A.; Estradé, S.; Golosovsky, I. V.; Salazar-Alvarez, G.; Vasilakaki, M.; Trohidou, K. N.; Varela, M.; Stanley, D. C.; Sinko, M.; Pechan, M. J.; Keavney, D. J.; Peiró, F.; Suriñach, S.; Baró, M. D.; Nogués, J.

2013-12-01

15

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

16

Preparation of magnetic spinel ferrite core\\/shell nanoparticles: Soft ferrites on hard ferrites and vice versa  

Microsoft Academic Search

Hard\\/soft CoFe2O4\\/ZnFe2O4 and soft\\/hard ZnFe2O4\\/CoFe2O4 core\\/shell nanoparticles were prepared by combining high-temperature thermolysis of metal oxide precursors with seed-mediated growth. Magnetic properties of the core\\/shell nanoparticles were compared to those of individual CoFe2O4 and ZnFe2O4 nanoparticles of similar size prepared by the same method. The structure of the core\\/shell materials was established using a combination of X-ray and neutron powder

Ombretta Masala; Darin Hoffman; Nalini Sundaram; Katharine Page; Thomas Proffen; Gavin Lawes; Ram Seshadri

2006-01-01

17

Collision safety of a hard-shell low-mass vehicle.  

PubMed

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 EuroSID1-dummy well below current injury tolerance criteria. PMID:8011053

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

1994-06-01

18

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

19

Antibonding. beta. * valence MOs in the inner-shell and outer-shell spectra of the fluorobenzenes  

SciTech Connect

Electron transmission, inner-shell electron energy loss and magnetic circular dichroism spectra have been analyzed in an effort to trace the positions of the sigma* antibonding valence MOs in benzene and its fluorinated derivatives. The correlation of negative-ion resonances in these systems shows clearly that a sigma* valence level descends with increasing fluorination so as to become the lowest virtual MO in hexafluorobenzene. In addition to the low-lying sigma* negative-ion shape resonances, several negative-ion Feshbach resonances are identified as involving 3s and 3p Rydberg orbitals. The carbon K-shell spectra of benzene and its fluorinated derivatives below the respective C 1s ionization potentials are dominated by excitations to 1..pi..* and 2..pi..* valence levels. A systematic shift of the sigma* levels to lower energy with increasing fluorination is observed which is consistent with the perfluoro effect. Resonances terminating at sigma*(C-C) are found to dominate the C 1s near continuum, with dramatic enhancement of these transitions in the more highly fluorinated species. Investigation of hexafluoro- and 1,2,4,5-tetrafluorobenzene by vacuum-ultraviolet magnetic circular dichroism in the vapor phase confirms the presence of bands which are not ..pi.. ..-->.. ..pi..*. Once again, low-lying sigma* MOs are invoked as terminating orbitals.

Hitchcock, A.P.; Fischer, P.; Gedanken, A.; Robin, M.B.

1987-01-29

20

Inner- and outer-shell electron dynamics in proton collisions with sodium atoms  

NASA Astrophysics Data System (ADS)

p+Na collisions have been investigated theoretically and experimentally at impact energies in the keV regime. We present results for capture and ionization processes, and, in particular, analyse the role of initial inner-shell electrons, whose active participation is identified in the experiments through the analysis of recoil-ion momentum spectra. Quantum-mechanical calculations within the independent particle model have been carried out for all active electrons. A very good overall agreement between the theoretical and experimental results is found. The calculations support the observation that capture from inner shells is an important reaction channel even at relatively low impact energies, and dominates total capture above 40 keV.

Zapukhlyak, M.; Kirchner, T.; Lüdde, H. J.; Knoop, S.; Morgenstern, R.; Hoekstra, R.

2005-07-01

21

Adsorption of gold ions from industrial wastewater using activated carbon derived from hard shell of apricot stones – An agricultural waste  

Microsoft Academic Search

In this study, hard shell of apricot stones was selected from agricultural solid wastes to prepare effective and low cost adsorbent for the gold separation from gold-plating wastewater. Different adsorption parameters like adsorbent dose, particle size of activated carbon, pH and agitation speed of mixing on the gold adsorption were studied. The results showed that under the optimum operating conditions,

Mansooreh Soleimani; Tahereh Kaghazchi

2008-01-01

22

Evidence for a highly elastic shell-core organization of cochlear outer hair cells by local membrane indentation.  

PubMed

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 microm/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; de Monvel, Jacques Boutet; Pesen, Devrim; Radmacher, Manfred; Hoh, Jan H; Ulfendahl, Mats

2005-04-01

23

Two-dimensional Penning ionization electron spectroscopy of open-shell metallocenes: outer valence ionic states of vanadocene and nickelocene.  

PubMed

In order to investigate outer valence ionic states of open-shell metallocenes, we have applied two-dimensional collision-energy/electron-energy-resolved Penning ionization electron spectroscopy (2D-PIES) upon collision with metastable He*(2(3)S) excited atoms as well as a high level ab initio molecular orbital calculation (the partial third-order quasiparticle theory of the electron propagator (P3)) to ionization from neutral ground states of vanadocene ((4)A2g) and nickelocene ((3)A2g). Assignments of observed Penning ionization electron/He I ultraviolet photoelectron spectra were consistent with the P3 calculation results for ionization of ? and ? spin electrons except for electron correlation bands observed by PIES. Negative collision energy dependence of partial Penning ionization cross-sections (CEDPICS) indicate attractive interaction with He*(2(3)S) around the molecule. Results by model potential calculation utilizing Li(2(2)S) instead of He*(2(3)S) for interaction between He*(2(3)S) and open-shell metallocenes do not explain the strong negative CEDPICS of the bands observed in PIES. PMID:23534703

Kishimoto, Naoki; Kimura, Miku; Ohno, Koichi

2013-04-11

24

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

25

Immunocytochemistry suggests that the prevalence of a sub-type of beta-proteins determines the hardness in the epidermis of the hard-shelled turtle.  

PubMed

The corneous layer of the epidermis in hard-shelled turtles largely derives from the accumulation of beta-proteins as indicated by microscopic, in situ hybridization, and immunocytochemical and Western blotting analysis. The expression of mRNAs of one of the most common type of beta-proteins shows higher expression in upper spinosus and pre-corneous keratinocytes of growing scutes. Two beta-proteins of 14-16?kDa, indicated as Tu2 and Tu17 and representing two subtypes of beta-proteins co-accumulate in the thick corneous layer of the epidermis in hard-shelled turtle. The two beta-proteins apparently mix in differentiating and mature corneocytes although Tu2 appears more prevalent than Tu17. The specific role of the different subtypes in the formation of the hard corneous material of the carapace and plastron is not clear. It is hypothesized that the relative amount of beta-proteins belonging to the two subclasses in relation to the alpha-keratin meshwork present in keratinocytes contributes to the formation of a variably resistant and inflexible corneous layer. Tu17 may have a more globular structure than Tu2 and is likely present in denser areas of the corneous layer containing also alpha-keratin. The increase of cysteine-glycine-rich beta-proteins in the matrix located among alpha-keratin filaments may allow the formation of a hard corneous material, probably through increase of cross-bridge formation and hydrophobicity. PMID:24254963

Alibardi, Lorenzo

2014-01-01

26

C --needs 4 e's to complete its outer shell ---> forms 4 covalent bonds by sharing e's with the other common elements ---> relatively equal sharing of electrons --->  

E-print Network

1 C -- needs 4 e's to complete its outer shell ---> forms 4 covalent bonds by sharing e's with the other common elements ---> relatively equal sharing of electrons ---> strong covalent bonds. The 4 atoms--O--H, >C==O 4 sp3 hybrid orbitals -- 2 have lone electron pairs and 2 form covalent bonds PRECURSOR

Frey, Terry

27

Fabrication of submicrometer pores with an outer shell using modified poly(vinyl alcohol) and the molecular or particle collection effect.  

PubMed

Pores with an outer shell (POS) are fabricated on the submicrometer scale using modified poly(vinyl alcohol) (PVA). An aqueous solution is mixed with cationic PVA and a water-based colloidal suspension of polystyrene (PS) spheres of submicrometer diameter. The mixture is then spin-coated onto a substrate. The resultant structure is immersed in toluene, which dissolves the PS spheres. As a result, POS are formed by PVA on the substrate. By using PS spheres with 500 nm diameter, the pore openings have a diameter of about 300 nm and are surrounded by the outer shell. This structure exhibits beneficial molecular and particle collection effects, which are attributed to the peripheral shell rising from the surface. In addition, POS can be formed using a photo-cross-linkable PVA that is often used for enzyme-immobilized hydrogel matrices. PMID:24067099

Emoto, Akira; Noguchi, Naomi; Kobayashi, Tomoko; Fukuda, Takashi

2013-10-01

28

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

29

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

30

Evidence for Significant Target Outer-Shell Excitation in Multiple-Electron Capture Collisions of Slow Highly Charged Ions with Many-Electron Atoms  

NASA Astrophysics Data System (ADS)

Unequivocal evidence for significant target outer-shell excitation accompanying multiple-electron capture, in slow collisions of highly charged ions with many-electron atoms, has been obtained by means of simultaneous Auger-electron and cold-target recoil-ion momentum spectroscopic measurements. For the 28 keV 15N7++Ar collision system, it is found that target excitation accompanies about 40% of all double-electron capture collisions. The evidence supports the predictions of the molecular classical overbarrier model by Niehaus [A. Niehaus, J. Phys. B 19, 2925 (1986)].

Hasan, A. A.; Emmons, E. D.; Hinojosa, G.; Ali, R.

1999-11-01

31

Removal of Escherichia coli, Enterococcus fecalis, coliphage MS2, poliovirus, and hepatitis A virus from oysters (Crassostrea virginica) and hard shell clams (Mercinaria mercinaria) by depuration.  

PubMed

Filter-feeding bivalve mollusks (shellfish) can bioaccumulate pathogenic microorganisms in up to 1000-fold higher levels than overlying waters, and therefore disease risks are associated with consuming raw or partially cooked shellfish. Many of these shellfish-borne diseases are due to enteric bacteria and viruses associated with fecal contamination. To control shellfish-borne diseases, guidelines for shellfish harvest waters and shellfish meat have been devised, which include cleansing of contaminated shellfish by depuration in controlled systems, heat pasteurization, or relay to clean waters. This study examines the depuration of oysters (Crassostrea virginica) and hard shell clams (Mercinaria mercinaria) in a flow-through depuration system under variable temperature (12 °C, 18 °C, and 25 °C), salinity (8 ppt, 18 ppt, and 28 ppt), turbidity (<1NTU, 10NTU, and 20NTU), pH (pH 7 and pH 8), and algae conditions (0 cells/mL and 50,000 cells/mL), with constant dissolved oxygen (5-7 mg/L). Oysters and hard shell clams were artificially contaminated with enteric microorganisms: Escherichia coli, Enterococcus faecalis, coliphage MS2, Poliovirus type-1 and Hepatitis A virus HM-175 (HAV), then depurated in 5-day trials with daily sampling. In oysters, optimizing environmental parameters of water temperature improved E. coli, MS2, poliovirus and HAV depuration, and optimized salinity improved E. coli, E. faecalis, and MS2 depuration rates. In hard shell clams, salinity improved E. coli and E. faecalis depuration rates. Adjusting turbidity, pH or algae did not improve microorganism depuration in either oysters or hard shell clams, with the exception of turbidity on E. faecalis in hard shell clams. Microorganism depuration rates in oysters from greatest to least were: MS2>E. coli>E. faecalis>poliovirus>HAV, and in clams depuration rates from greatest to least were: E. coli>E. faecalis>HAV>MS2>poliovirus. Because E. coli and E. faecalis were removed at faster rates than HAV and poliovirus, these fecal bacteria appear to be poor process indicators of the virological quality of depurated oysters and hard shell clams. PMID:20864199

Love, David C; Lovelace, Greg L; Sobsey, Mark D

2010-10-15

32

Removable inner turbine shell with bucket tip clearance control  

Microsoft Academic Search

A turbine includes a plurality of inner shell sections mounting first and second stage nozzle and shroud portions. The inner shell sections are pinned to an outer containment shell formed of sections to preclude circumferential movement of the inner shell relative to the outer shell and enable thermal expansion and contraction of the inner shell relative to the outer shell.

B. F. Sexton; H. M. Knuijt; S. Q. Eldrid; A. Myers; K. E. Coneybeer; D. M. Johnson; I. R. Kellock

2000-01-01

33

One-pot synthesis of biocompatible Te@phenol formaldehyde resin core-shell nanowires with uniform size and unique fluorescent properties by a synergized soft-hard template process.  

PubMed

One-pot hydrothermal process has been developed to synthesize uniform Te@phenol formaldehyde resin core-shell nanowires with unique fluorescent properties. A synergistic soft-hard template mechanism has been proposed to explain the formation of the core-shell nanowires. The Te@phenol formaldehyde resin core-shell nanowires display unique fluorescent properties, which give strong luminescent emission in the blue-violet and green regions with excitation wavelengths of 270 nm and 402 nm, respectively. PMID:21071820

Qian, Haisheng; Zhu, Enbo; Zheng, Shunji; Li, Zhengquan; Hu, Yong; Guo, Changfa; Yang, Xingyun; Li, Liangchao; Tong, Guoxiu; Guo, Huichen

2010-12-10

34

One-pot synthesis of biocompatible Te@phenol formaldehyde resin core-shell nanowires with uniform size and unique fluorescent properties by a synergized soft-hard template process  

NASA Astrophysics Data System (ADS)

One-pot hydrothermal process has been developed to synthesize uniform Te@phenol formaldehyde resin core-shell nanowires with unique fluorescent properties. A synergistic soft-hard template mechanism has been proposed to explain the formation of the core-shell nanowires. The Te@phenol formaldehyde resin core-shell nanowires display unique fluorescent properties, which give strong luminescent emission in the blue-violet and green regions with excitation wavelengths of 270 nm and 402 nm, respectively.

Qian, Haisheng; Zhu, Enbo; Zheng, Shunji; Li, Zhengquan; Hu, Yong; Guo, Changfa; Yang, Xingyun; Li, Liangchao; Tong, Guoxiu; Guo, Huichen

2010-12-01

35

Formulation design of double-layer in the outer shell of dry-coated tablet to modulate lag time and time-controlled dissolution function: Studies on micronized ethylcellulose for dosage form design (VII)  

Microsoft Academic Search

The dry-coated tablet with optimal lag time was designed to simulate the dosing time of drug administration according to the\\u000a physiological needs. Different compositions of ethylcellulose (EC) powder with a coarse particle (167.5 ?m) and several fine\\u000a particles (<6 ?m), respectively, were mixed to formulate the whole layer of the outer shell of dry-coated tablets. The formulations\\u000a containing different weight

Shan-Yang Lin; Kung-Hsu Lin; Mei-Jane Li

2004-01-01

36

Target outer-shell excitation in multiple-electron capture collisions of slow highly-charged ions with many- electron atoms  

NASA Astrophysics Data System (ADS)

The dominant process in the collision of a slow (v < 1 a.u.) highly charged ion with a multielectron target is electron transfer from the target into singly or multiply excited states on the highly charged ion. The excited states formed during the collision will eventually decay either by photon or Auger-electron emission or a combination of both. Our understanding of multielectron processes in such collisions has been hindered by the limited ability of previously employed experimental techniques to disentangle the final phenomenological collision products. This dissertation reports the development of a state-of-the-art experimental apparatus to investigate multielectron processes at an unprecedented level of detail. The experimental approach involves the use of supersonic target jets, position imaging techniques, and time-of-flight triple-coincidence detection of Auger electrons, scattered projectile and recoil ions. This powerful combination enables simultaneous Auger-electron and cold-target recoil-ion momentum (COLTRIMS) spectroscopic measurements. This approach has resolved a long standing controversy by providing unequivocal experimental evidence for target outer-shell excitation accompanying multiple electron capture as predicted by the molecular classical overbarrier model (MCBM) [A. Niehaus, J. Phys. B 19, 2925 (1986)]. This work focuses on target excitation in double-electron capture processes in the 28-keV N 7+ + Ar and 60-keV C6+ + Ne collision systems. The results clearly reveal that multiple-electron capture can be accompanied by significant target excitation, and that the recoil-ion charge state is not a good indicator of the number of active electrons during the collision, or of the number of electrons actually captured by the projectile.

Hasan, Ahmad A.

37

Outer-shell photodetachment of the metastable Mg- [core]3s3p2 and Ca- [core]4s4p2 Pe4 states  

NASA Astrophysics Data System (ADS)

We report on calculated outer-shell photodetachment cross sections from the metastable [core]nsnp2Pe4 states in Mg- (n=3) and Ca- (n=4) negative ions in the photon energy range ?=0-10eV . Double-ionization thresholds for MgII and CaII as well as doubly excited thresholds of the residual atoms MgI and CaI are located within the photon energy range considered and thus doubly and triply excited states of both Mg- and Ca- are reached. We use a complex scaled configuration interaction (CSCI) method for the three active electrons supplemented with a sophisticated model potential as developed by Laughlin [Phys. Scr. 45, 238 (1992)] to account for core-valence interactions. The CI calculations are based on Mg+ and Ca+ one-electron orbitals expanded in terms of B -spline basis set. We compare our cross sections with the only calculation available up to a photon energy 0.25Ry (?˜3.4eV) [Zeng , Phys. Rev. A 62, 022713 (2000)] performed by using the R -matrix method, in which only one Po4 resonance for Mg- and two ( Po4 and Do4 ) for Ca- were predicted. In this work, by analyzing both the cross sections and the locations of the S -matrix poles in the complex plane, we are able to predict six Po4 , four Do4 , and four So4 resonant states for Mg- , and three Po4 and two Do4 resonant states in Ca- .

Sanz-Vicario, José Luis; Cardona, Juan Carlos; Lindroth, Eva

2008-11-01

38

Structural Determinants of the Outer Shell of ?-Carboxysomes in Synechococcus elongatus PCC 7942: Roles for CcmK2, K3-K4, CcmO, and CcmL  

PubMed Central

Cyanobacterial CO2-fixation is supported by a CO2-concentrating mechanism which improves photosynthesis by saturating the primary carboxylating enzyme, ribulose 1, 5-bisphosphate carboxylase/oxygenase (RuBisCO), with its preferred substrate CO2. The site of CO2-concentration is a protein bound micro-compartment called the carboxysome which contains most, if not all, of the cellular RuBisCO. The shell of ?-type carboxysomes is thought to be composed of two functional layers, with the inner layer involved in RuBisCO scaffolding and bicarbonate dehydration, and the outer layer in selective permeability to dissolved solutes. Here, four genes (ccmK2-4, ccmO), whose products were predicted to function in the outer shell layer of ?-carboxysomes from Synechococcus elongatus PCC 7942, were investigated by analysis of defined genetic mutants. Deletion of the ccmK2 and ccmO genes resulted in severe high-CO2-requiring mutants with aberrant carboxysomes, whilst deletion of ccmK3 or ccmK4 resulted in cells with wild-type physiology and normal ultrastructure. However, a tandem deletion of ccmK3-4 resulted in cells with wild-type carboxysome structure, but physiologically deficient at low CO2 conditions. These results revealed the minimum structural determinants of the outer shell of ?-carboxysomes from this strain: CcmK2, CcmO and CcmL. An accessory set of proteins was required to refine the function of the pre-existing shell: CcmK3 and CcmK4. These data suggested a model for the facet structure of ?-carboxysomes with CcmL forming the vertices, CcmK2 forming the bulk facet, and CcmO, a “zipper protein,” interfacing the edges of carboxysome facets. PMID:22928045

Rae, Benjamin D.; Long, Benedict M.; Badger, Murray R.; Price, G. Dean

2012-01-01

39

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

40

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

41

75 FR 803 - Safety Zone; FRONTIER DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort Sea...  

Federal Register 2010, 2011, 2012, 2013

...FRONTIER DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort...Chukchi and Beaufort Sea Outer Continental Shelf, Alaska, from 12:01 a...coast in the Beaufort Sea Outer Continental Shelf, Alaska. Shell...

2010-01-06

42

The ultrastructure of shelled and unshelled cashew nuts.  

PubMed

Cashew nuts have many attributes, including sensory, nutritional and health appeal, which contribute to their worldwide acceptance. We demonstrate details of the microstructure of shelled and unshelled cashew kernels with regard to pericarp and cotyledon organization. This study also provides evidence of the colonization of these kernels by filamentous fungi. Nuts were examined by scanning electron and confocal scanning laser microscopy. Staining with acridine orange was performed. A tight lignified palisade layer adjacent to the exocarp surface explains the hardness of the shell's pericarp. The mesocarp contains large secretory cavities that confer a spongy property to this tissue. Papillose cells, which are responsible for secreting CNSL (cashew nutshell liquid), were observed to cover the inner wall of these cavities. Lipid components are readily released from the parenchyma and appear as oil droplets. The outer surface of the shelled samples exhibited a dense Aspergillus infestation. PMID:24045033

Muniz, Celli R; Freire, Francisco C O; Soares, Arlete Aparecida; Cooke, Peter H; Guedes, Maria I F

2013-01-01

43

46 CFR 154.170 - Outer hull steel plating.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

44

46 CFR 154.170 - Outer hull steel plating.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

45

46 CFR 154.170 - Outer hull steel plating.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Outer hull steel plating. 154.170 Section 154.170 Shipping...Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph...of this section, the outer hull steel plating, including the shell and deck...

2010-10-01

46

46 CFR 154.170 - Outer hull steel plating.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

47

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

48

Optimum rotationally symmetric shells for flywheel rotors  

DOEpatents

A flywheel rim support formed from two shell halves. Each of the shell halves has a disc connected to the central shaft. A first shell element connects to the disc at an interface. A second shell element connects to the first shell element. The second shell element has a plurality of meridional slits. A cylindrical shell element connects to the second shell element. The cylindrical shell element connects to the inner surface of the flywheel rim. A flywheel rim support having a disc connected an outer diameter of a shaft. Two optimally shaped shell elements connect to the optimally shaped disc at an interface. The interface defines a discontinuity in a meridional slope of said support. A cylindrical shell element connects to the two shell elements. The cylindrical shell element has an outer surface for connecting to the inner surface of the flywheel rim. A flywheel rim casing includes an annular shell connected to the central shaft. The annular shell connects to the flywheel rim. A composite shell surrounds the shaft, annular shell and flywheel rim.

Blake, Henry W. (Oak Ridge, TN)

2000-01-01

49

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

50

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

Federal Register 2010, 2011, 2012, 2013

...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

51

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

52

Periodically kicked hard oscillators G. A. Cecchi  

E-print Network

Periodically kicked hard oscillators G. A. Cecchi Departamento de Fisica, U.N.L.P.,Argentina D. L for publication 25 November 1992) A model of a hard oscillator with analytic solution is presented. Its behavior. It is shown that the general structure of such an oscillator includes four distinct regions; the outer two

53

The Outer Limits: English.  

ERIC Educational Resources Information Center

The Quinmester course "The Outer Limits" involves an exploration of unknown worlds, mental and physical, through fiction and nonfiction. Its purpose is to focus attention on the ongoing conquest of the frontiers of the mind, the physical world, and outer space. The subject matter includes identification and investigation of unknown worlds in the…

Tyler, Barbara R.; Biesekerski, Joan

54

Core-shell nanostructured catalysts.  

PubMed

Novel nanotechnologies have allowed great improvements in the syn-thesis of catalysts with well-controlled size, shape, and surface properties. Transition metal nanostructures with specific sizes and shapes, for instance, have shown great promise as catalysts with high selectivities and relative ease of recycling. Researchers have already demonstrated new selective catalysis with solution-dispersed or supported-metal nanocatalysts, in some cases applied to new types of reactions. Several challenges remain, however, particularly in improving the structural stability of the catalytic active phase. Core-shell nanostructures are nanoparticles encapsulated and protected by an outer shell that isolates the nanoparticles and prevents their migration and coalescence during the catalytic reactions. The synthesis and characterization of effective core-shell catalysts has been at the center of our research efforts and is the focus of this Account. Efficient core-shell catalysts require porous shells that allow free access of chemical species from the outside to the surface of nanocatalysts. For this purpose, we have developed a surface-protected etching process to prepare mesoporous silica and titania shells with controllable porosity. In certain cases, we can tune catalytic reaction rates by adjusting the porosity of the outer shell. We also designed and successfully applied a silica-protected calcination method to prepare crystalline shells with high surface area, using anatase titania as a model system. We achieved a high degree of control over the crystallinity and porosity of the anatase shells, allowing for the systematic optimization of their photocatalytic activity. Core-shell nanostructures also provide a great opportunity for controlling the interaction among the different components in ways that might boost structural stability or catalytic activity. For example, we fabricated a SiO?/Au/N-doped TiO? core-shell photocatalyst with a sandwich structure that showed excellent catalytic activity for the oxidation of organic compounds under UV, visible, and direct sunlight. The enhanced photocatalytic efficiency of this nanostructure resulted from an added interfacial nonmetal doping, which improved visible light absorption, and from plasmonic metal decoration that enhanced light harvesting and charge separation. In addition to our synthetic efforts, we have developed ways to evaluate the accessibility of reactants to the metal cores and to characterize the catalytic properties of the core-shell samples we have synthesized. We have adapted infrared absorption spectroscopy and titration experiments using carbon monoxide and other molecules as probes to study adsorption on the surface of metal cores in metal oxide-shell structures in situ in both gas and liquid phases. In particular, the experiments in solution have provided insights into the ease of diffusion of molecules of different sizes in and out of the shells in these catalysts. PMID:23268644

Zhang, Qiao; Lee, Ilkeun; Joo, Ji Bong; Zaera, Francisco; Yin, Yadong

2013-08-20

55

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

56

Active control of radiated noise from a cylindrical shell using external piezoelectric panels  

E-print Network

Control architectures and methodologies are developed for the reduction of radiated noise from a thick-walled cylindrical shell using external piezoelectric panels. The proposed approach is to cover the shell's outer surface ...

Song, Kyungyeol, 1972-

2002-01-01

57

The Outer Ejecta  

NASA Astrophysics Data System (ADS)

? Carinae is surrounded by a complex circumstellar nebula ejected during more than one eruption, the great eruption in the 1840s and the second or lesser eruption in the 1890s. Beyond the well-defined edges of its famous bipolar nebula are additional nebulous features and ejecta referred to as the outer ejecta. The outer ejecta includes a variety of structures of very different sizes and morphologies distributed in a region 0.67 pc in diameter with a mass of > 2-4 M?. Some individual features in the outer ejecta are moving extremely fast, up to 3,200 km/s, with most of the expansion velocities between 400-900 km/s. As a consequence of these high velocities, structures in the outer ejecta interact with the surrounding medium and with each other. The strong shocks that arise from these interactions give rise to soft X-ray emission. The global expansion pattern of the outer ejecta reveals an overall bipolar distribution, giving a symmetric structure to its morphologically more irregular appearance. The long, highly collimated filaments, called strings, are particularly unusual. The material in the strings follow a Hubble-flow and appear to originate at the central star. The properties of the nebulae associated with other LBVs also are described and compared with ? Car. HR Car and AG Car show similar bipolar morphologies but are much older; HR Car's nebula may be ? Car's older twin. The larger, extended nebulae detected around the giant eruption LBV P Cygni, and the extended nebulosity associated with AG Car and HR Car could be either from previous eruptions or facsimiles to ? Car's outer ejecta.

Weis, Kerstin

58

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

59

CDF Central Outer Tracker  

Microsoft Academic Search

The Central Outer Tracker is a large cylindrical drift chamber constructed to replace Collider Detector at Fermilab's original central drift chamber for the higher luminosity expected for Run 2 at the Fermilab Tevatron. The chamber's drift properties are described in the context of meeting the operating requirements for Run 2. The design and construction of the chamber, the front-end readout

T. Affolder; D. Allspach; D. Ambrose; J. Bialek; W. Bokhari; M. Brozovic; M. Binkley; K. Burkett; A. Byon-Wagner; F. Cogswell; N. Dressnandt; Z. Feng; M. Franklin; L. Galtieri; D. W Gerdes; J. Greenwood; V. Guarino; J Guimaraes da Costa; R. Haggerty; C. Hall; J. Heinrich; A. Holloway; T. Jacobi; K. Kephart; D. Khazins; Y. K Kim; M. Kirby; W. Kononenko; A. V. Kotwal; J. Kraus; T. M Liss; N. Lockyer; R. Madrak; T. Miao; A. Mukherjee; C. Neu; M. Newcomer; J. M Niczyporuk; L. Nodulman; W. Orejudous; T. J Phillips; K. T Pitts; W. Reigler; R. Richards; C. Rivetta; W. J Robertson; R. Roser; L. Sadler; R. Sandberg; S. Sansone; R. Schmitt; K. Schultz; D. Shuman; R. Silva; P. Singh; R. Snihur; P. Tamburello; J. Taylor; R. Thurman-Keup; D. Tousignant; F. Ukegawa; R Van Berg; G. Veramendi; T. Vickey; J. Wacker; R. L Wagner; R. Weidenbach; W. C Wester; H. H. Williams; P. Wilson; P. Wittich; A. Yagil; I. Yu; S. Yu; J. C Yun

2004-01-01

60

75 FR 3915 - Environmental Documents Prepared in Support of Sand and Gravel Activities on the Outer...  

Federal Register 2010, 2011, 2012, 2013

...Environmental Documents Prepared in Support of Sand and Gravel Activities on the Outer Continental...prepared and/or adopted by the MMS for three sand and gravel activities proposed on the Outer...noncompetitive basis, the rights to OCS sand, gravel, or shell resources for...

2010-01-25

61

CDF Central Outer Tracker  

NASA Astrophysics Data System (ADS)

The Central Outer Tracker is a large cylindrical drift chamber constructed to replace Collider Detector at Fermilab's original central drift chamber for the higher luminosity expected for Run 2 at the Fermilab Tevatron. The chamber's drift properties are described in the context of meeting the operating requirements for Run 2. The design and construction of the chamber, the front-end readout electronics, and the high-voltage system are described in detail. Wire aging considerations are also discussed.

Affolder, T.; Allspach, D.; Ambrose, D.; Bialek, J.; Bokhari, W.; Brozovic, M.; Binkley, M.; Burkett, K.; Byon-Wagner, A.; Cogswell, F.; Dressnandt, N.; Feng, Z.; Franklin, M.; Galtieri, L.; Gerdes, D. W.; Greenwood, J.; Guarino, V.; Guimaraes da Costa, J.; Haggerty, R.; Hall, C.; Heinrich, J.; Holloway, A.; Jacobi, T.; Kephart, K.; Khazins, D.; Kim, Y. K.; Kirby, M.; Kononenko, W.; Kotwal, A. V.; Kraus, J.; Liss, T. M.; Lockyer, N.; Madrak, R.; Miao, T.; Mukherjee, A.; Neu, C.; Newcomer, M.; Niczyporuk, J. M.; Nodulman, L.; Orejudous, W.; Phillips, T. J.; Pitts, K. T.; Reigler, W.; Richards, R.; Rivetta, C.; Robertson, W. J.; Roser, R.; Sadler, L.; Sandberg, R.; Sansone, S.; Schmitt, R.; Schultz, K.; Shuman, D.; Silva, R.; Singh, P.; Snihur, R.; Tamburello, P.; Taylor, J.; Thurman-Keup, R.; Tousignant, D.; Ukegawa, F.; Van Berg, R.; Veramendi, G.; Vickey, T.; Wacker, J.; Wagner, R. L.; Weidenbach, R.; Wester, W. C.; Williams, H. H.; Wilson, P.; Wittich, P.; Yagil, A.; Yu, I.; Yu, S.; Yun, J. C.

2004-07-01

62

Buffalo Outer Harbor Quays  

Microsoft Academic Search

Buffalo, a once prominent American city hit by hard times, has the opportunity to rebuild. It has industrial resources and transport options. It has a booming education system and medical business. Its technology sector is rapidly expanding. The city has a chance right now to create new glory days. This project is about transforming a forgotten piece of land, a

Ryan Decker

2010-01-01

63

Ionization from the outer shell of Ar by proton impact  

NASA Astrophysics Data System (ADS)

Recent results for proton-argon total ionization cross sections [Kirchner et al. Phys. Rev. Lett. 79, 1658 (1997)] show large disagreement between theory and experiment for energies below 80 keV. To address this problem we have employed a recently developed theoretical method with a more pragmatic approach to the charge screening both in the initial and final channels. The target is considered as a one-electron atom and the interactions between this active electron and remaining target electrons are treated by a model potential including both short- and long-range effects. In the final channel the usual product of two continuum distorted wave functions each associated with a distinct electron-nucleus interaction is used. New results in the present calculation show good agreement in total cross sections for the energy range 10 300 keV with the measurement of Rudd et al. [Rev. Mod. Phys. 57, 965 (1985)].

Bhattacharya, S.; Das, R.; Deb, N. C.; Roy, K.; Crothers, D. S.

2003-11-01

64

BV photometry of five shell galaxies  

NASA Astrophysics Data System (ADS)

Current views consider shell structures as bona fide signatures of a recent minor/major merging event though also weak interaction models (WIM) could produce long lasting shells on host galaxies possessing a stellar thick disc. We present a B V band photometric study of a sample of 5 shell galaxies belonging to the Malin & Carter (1983) compilation. The structural properties and colors of the galaxies, as well as the colors of their shells are examined in detail. We did not find signatures of the presence of double nuclei. NGC 7585 is the only E galaxy in the sample and has a moderately boxy structure. The other galaxies have either a discy structure or are mixed E/S0 type galaxies. NGC 474 is a true lenticular. NGC 6776 shows a diffuse asymmetric outer structure and a system of tails of the the same color of the galaxy body; but not clear shells. In general, the color of the shells in our sample is similar or slightly redder than that of the host galaxy, whose color, in turn, is typical of the early-type morphological class. One of the outer shells of NGC 474 is significantly bluer than the body of the galaxy. Since NGC 474 appears to be interacting with NGC 470, the color of this one shell could be explained as result of a recent acquisition of material through tidal interaction. The WIM hypothesis could explain both the red and the blue shells of NGC 474, this latter acquired from the fly-by of the nearby companion NGC 470, but the lack of the constancy of shell surface brightness as a ratio of the underlying galaxy brightness argues against WIM. We speculate about evidence, which also comes from different observations, that suggests a merging/accretion origin of the shells. Based on observations obtained at the Observatoire de Haute Provence, CNRS, Saint Michel l'Observatoire, France and ESO, La Silla, Chile

Pierfederici, F.; Rampazzo, R.

2004-06-01

65

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

PubMed

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. PMID:25180699

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

2014-10-24

66

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

67

Photoionization of the outer electrons in noble gas endohedral atoms  

SciTech Connect

We suggest a prominent modification of the outer shell photoionization cross section in noble gas (NG) endohedral atoms NG-C{sub n} under the action of the electron shell of fullerene C{sub n}. This shell leads to two important effects: a strong enhancement of the cross section due to fullerene shell polarization under the action of the incoming electromagnetic wave and to prominent oscillation of this cross section due to the reflection of a photoelectron from the NG by the fullerene shell. Both factors lead to powerful maxima in the outer shell ionization cross sections of NG-C{sub n}, which we call giant endohedral resonances. The oscillator strength reaches a very large value in the atomic scale, 25. We consider atoms of all noble gases except He. The polarization of the fullerene shell is expressed in terms of the total photoabsorption cross section of the fullerene. The photoelectron reflection is taken into account in the framework of the so-called bubble potential, which is a spherical {delta}-type potential. It is assumed in the derivations that the NG is centrally located in the fullerene. It is also assumed, in accordance with the existing experimental data, that the fullerene radius R{sub C} is much larger than the atomic radius r{sub A} and the thickness {delta}{sub C} of the fullerene shell. As was demonstrated recently, these assumptions allow us to represent the NG-C{sub n} photoionization cross section as a product of the NG cross section and two well-defined calculated factors.

Amusia, M. Ya. [Hebrew University, Racah Institute of Physics (Israel)], E-mail: amusia@vms.huji.ac.il; Baltenkov, A. S. [Academy of Sciences of the Republic of Uzbekistan, Arifov Institute of Electronics (Uzbekistan); Chernysheva, L. V. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2008-08-15

68

Shell Games.  

ERIC Educational Resources Information Center

The author critiques the program design and educational aspects of the Shell Games, a program developed by Apple Computer, Inc., which can be used by the teacher to design objective tests for adaptation to specific assessment needs. (For related articles, see EC 142 959-962.) (Author)

Atkinson, Bill

1982-01-01

69

Management of outer space  

NASA Astrophysics Data System (ADS)

Various aspects of space-environment management are discussed. Attention is called to the fact that, while space radio communications are already under an adequate management by the International Communications Union, the use of nuclear power sources is regulated by the recently adopted set of principles, and space debris will be discussed in the near future at the UN COPUOS, other aspects of management of outer space received little or no attention of the international community. These include the competency of crews and technical equipment of spacecraft launched by newcomers to space exploration; monitoring of locations and motions of space objects (now in national hands), with relevant data made accessible through a computer network; and the requirement to use space only for beneficial purposes and not for promoting narrow and debatable interests damaging the outer space environment and impeding on astronomical observations. It is suggested that some of these tasks would be best performed by an international space agency within the UN system of organizations.

Perek, Lubos

1993-10-01

70

Colloidal liquids of yolk-shell particles  

E-print Network

In this paper we develop statistical mechanical tools to describe the intermediate- and long-time collective- and self-diffusion properties of a liquid of strongly-interacting hollow spherical particles (shells), each bearing a smaller solid sphere (yolk) in its interior. To decouple two complex effects we assume that the hydrodynamic interactions can be accounted for through the effective short-time self-diffusion coefficients $D^0_s$ and $D^0_y$ that describe the short-time Brownian motion of the yolk and the shell particles, and develop a self-consistent generalized Langevin equation theory to describe the intermediate- and long-time effects of the direct shell-shell, yolk-shell and yolk-yolk interactions. In a concrete application, we consider the simplest yolk-shell model system involving purely repulsive hard-body interactions between all (shell and yolk) particles. Using a softened version of these interparticle potentials we perform Brownian dynamics simulations to determine the mean squared displacement of both types of particles, as well as the intermediate scattering function of the yolk-shell complex. We compare the theoretical and simulation 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, influences the dynamic properties in a predictable manner, fully captured by the theory.

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

2014-07-23

71

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

72

Building Atoms Shell by Shell.  

ERIC Educational Resources Information Center

Describes an atom-building activity where students construct three-dimensional models of atoms using a styrofoam ball as the nucleus and pom-poms, gum drops, minimarshmallows, or other small items of two different colors to represent protons and neutrons attached. Rings of various sizes with pom-poms attached represent electron shells and…

Sussman, Beverly

1993-01-01

73

Inferring the State of Tidally-heated Satellite Ice Shells from Global Shape Measurements  

Microsoft Academic Search

Several icy satellites of the outer solar system, notably Europa and Enceladus, are sufficiently tidally heated that they likely possess ice shells overlying oceans. Because tidal heating varies spatially [1], variations in ice shell thickness are likely to occur [2]. Lateral variations in shell thickness will in turn give rise to global topographic variations. The amplitude of this long-wavelength topography

F. Nimmo; P. C. Thomas; R. T. Pappalardo; W. B. Moore

2006-01-01

74

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

75

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

76

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

77

Scattering Functions of Yolk-Shell Particles  

SciTech Connect

The single-particle small-angle scattering properties of the yolk-shell particle, a new type of core-shell particle with a mobile core within the hosting shell, are systematically investigated. The Debye spatial autocorrelation function, pair distance distribution function and intraparticle structure factor (form factor) are calculated and compared to the corresponding scattering functions of reference systems of hard sphere and concentric core-shell particles with identical sizes. Based on our theoretical calculations, we find that the broken centrosymmetry, originating from the mobility of the trapped yolk, results in an imaginary scattering amplitude. As a result, it contributes an additional destructive interference term which smears certain features present in the scattering functions of the reference systems. Based on our theoretical models, we present the prospect of jointly using small angle neutron and x-ray scattering techniques to quantitatively determine the structural characteristics of yolk-shell particles.

Li, Xin [ORNL] [ORNL; Liu, Kao-Hsiang [National Taiwan University] [National Taiwan University; Wu, Bin [ORNL] [ORNL; Sanchez-Diaz, Luis E [ORNL] [ORNL; Smith, Gregory Scott [ORNL] [ORNL; Chen, Wei-Ren [ORNL] [ORNL

2013-01-01

78

Synthesis and properties of bimagnetic core-shell nanoparticles  

NASA Astrophysics Data System (ADS)

Bimagnetic core-shell nanoparticles are synthesized from high-temperature solution phase coating of FePt core with tunable Fe3O4, CoFe2O4 or FeCo shell. Magnetic properties of the as-synthesized core-shell particles are dependent on shell material and its thickness due to the exchange coupling between core and shell. Upon reductive annealing, an assembly of the core/shell nanoparticles is transformed into a hard magnetic nanocomposite with enhanced energy product which is 30% higher than single FePt phase. With proper choice of materials and dimension tuning of both core and shell, these core-shell nanoparticles may be used as building blocks for creation of novel functional nanomaterials for various magnetic applications.

Nandwana, Vikas; Chaubey, Girija; Yano, Kazuaki; Liu, Ping

2006-10-01

79

Outer Solar System Nomenclature  

NASA Technical Reports Server (NTRS)

This grant has supported work by T. Owen and B. A. Smith on planetary and satellite nomenclature, carried out under the general auspices of the International Astronomical Union (IAU). The IAU maintains a Working Group on Planetary and Satellite Nomenclature (WGPSN) whose current chair is Prof.Kaare Aksnes of the Rosseland Institute for Theoretical Astrophysics in Oslo, Norway. Both Owen and Smith are members of the WGPSN; Owen as chair of the Outer Solar System Task Group, and Smith as chair of the Mars Task Group. The major activity during the last grant period (2002) was the approval of several new names for features on Mars by Smith's group and features on Jovian satellites plus new names for satellites of Jupiter, Saturn and Uranus by Owen's group. Much of this work was accomplished by e-mail exchanges, but the new nomenclature was formally discussed and approved at a meeting of the WGPSN held in conjunction with the Division for Planetary Sciences meeting in Birmingham, Alabama in October 2002.

Owen, Tobias C.; Grant, John (Technical Monitor)

2003-01-01

80

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

81

Interface stresses in laminated cylindrical shells  

SciTech Connect

A theory is established by treating each layer of a laminated cylindrical shell as a separate thin shell with the interface stresses as unknown loading parameters. Equilibrium equations are satisfied exactly. Other elasticity equations are assumed to be approximately satisfied or satisfied on the average through the thickness of each layer. By satisfying continuity in displacement at each interface and the traction boundary conditions at inner and outer boundary surfaces, the interface stresses are determined systematically without limitation of the number of layers of the shell. Present results show excellent agreements with the exact solution for homogeneous isotropic thick cylinders. Results are presented for the basic problem of double layered shells which may be used as bench mark solutions for future reference. Numerical examples for laminated cylinders consisting of layers of orthotropic materials are presented for illustrative purposes.

Wang, J.T.S.; Lin, C.C. [National Chung-Hsing Univ., Taichung (Taiwan, Province of China). Institute of Applied Mathematics

1993-12-31

82

78 FR 1759 - Notice of Approval of Clean Air Act Outer Continental Shelf Minor Source/Title V Minor Permit...  

Federal Register 2010, 2011, 2012, 2013

...Approval of Clean Air Act Outer Continental Shelf Minor Source/Title V Minor Permit Modification Issued to Shell Offshore, Inc...Air Act Outer Continental Shelf (``OCS'') Minor Source/Title V Permit No. R10OCS03000 (``permits''). The...

2013-01-09

83

Shell width Three bumps  

E-print Network

Shell width Three bumps Five spines Female (left) and male (right) green crab shell undersides Green crab shell color Green crabs can be identified by their unique shell shape. Adults can have shells up to four inches across in width. Green crab diagram: Tim Sullivan. Green crab with hand & green

84

Outer Planet Assessment Group (OPAG) Recommended Exploration Strategy for the Outer Planets 2013-2022  

NASA Astrophysics Data System (ADS)

The Outer Solar System provides critical clues to how solar systems form and evolve, how planetary systems become habitable, and how life has evolved in our solar system. NASA's Outer Planets Assessment Group (OPAG) was established to identify scientific priorities and pathways for Outer Solar System exploration. Fundamental new discoveries are best made with a mixture of mission sizes that includes large (flagship) missions, and medium-sized and smaller-sized (as practical) missions, along with vigorous support for basic research, data analysis, and technology development — a balanced strategy most efficiently implemented as an Outer Planets Exploration Program. Missions to the Outer Solar System are major undertakings, requiring large and expensive launch vehicles, long mission durations, highly reliable (frequently radiation hard) and autonomous spacecraft, and radioisotope power sources in most cases. OPAG has recommended to the US National Research Council Planetary Science Decadal Survey to explore the possibilities for ‘small flagship' class missions to be considered, providing a greater range of choice and capabilities in the mix to balance program size and science return. With the Galileo mission concluded, the Cassini equinox mission in progress, and Juno in development, OPAG has strongly endorsed the competitive selection by NASA of the Jupiter Europa Orbiter (JEO) as the next Outer Planets Flagship and as part of the Europa Jupiter System Mission (EJSM) with ESA, a collaboration that includes a Ganymede orbiter and an increased focus on Jupiter science; OPAG has strongly recommended support of JEO and EJSM in the Decadal Survey. In addition, OPAG has strongly endorsed approval by NASA of the Cassini Solstice Mission, including the Juno-like end-of-mission scenario, given the likely phenomenal return on investment. OPAG also advocates the need for a focused technology program for the next Outer Planet Flagship Mission after EJSM, in order to be ready for a launch in the mid-2020s. In this regard, a return to Titan and Enceladus is the highest priority. Technologies that require long-term investment for missions beyond the next decade should also be considered. Medium-sized, New Frontiers class missions that should be considered in the interim include (but not in priority order) probe missions to the giant planets, an Io observer, a Neptune/Triton/KBO rendezvous, a Titan in-situ explorer or probe, and a Uranus orbiter, and OPAG recommended to the Decadal Survey that these be studied, costed, and if deemed feasible added to the approved New Frontiers mission set. Full details can be accessed through the OPAG website at http://www.lpi.usra.edu/decadal/opag/index.html.

McKinnon, William B.; Steering Committee, Opag; Planets Community, Outer

2010-05-01

85

Turbine airfoil with outer wall thickness indicators  

DOEpatents

A turbine airfoil usable in a turbine engine and including a depth indicator for determining outer wall blade thickness. The airfoil may include an outer wall having a plurality of grooves in the outer surface of the outer wall. The grooves may have a depth that represents a desired outer surface and wall thickness of the outer wall. The material forming an outer surface of the outer wall may be removed to be flush with an innermost point in each groove, thereby reducing the wall thickness and increasing efficiency. The plurality of grooves may be positioned in a radially outer region of the airfoil proximate to the tip.

Marra, John J; James, Allister W; Merrill, Gary B

2013-08-06

86

The 4 K outer cryostat for the CUORE experiment: construction and quality control  

E-print Network

The external shell of the CUORE cryostat is a large cryogen-free system designed to host the dilution refrigerator and the bolometers of the CUORE experiment in a low radioactivity environment. The three vessels that form the outer shell were produced and delivered to the Gran Sasso underground Laboratories in July 2012. In this paper, we describe the production techniques and the validation tests done at the production site in 2012.

F. Alessandria; M. Biassoni; G. Ceruti; A. Chiarini; M. Clemenza; O. Cremonesi; V. Datskov; S. Dossena; M. Faverzani; E. Ferri; A. Nucciotti; M. Perego; E. Previtali; M. Sisti; L. Taffarello; F. Terranova

2013-06-06

87

The Double-Shell Structure of the Variable Young Planetary Nebula IC 4997  

NASA Astrophysics Data System (ADS)

VLA-A 3.6 cm continuum and H92 alpha observations and long-slit optical spectroscopy of IC 4997 are presented. The radio continuum map shows that IC 4997 is a double-shell planetary nebula consisting of a faint, knotty outer shell of size ~=2."7 x 1."4, elongated at position angle ~=54 deg, and a bright, circular inner shell of ~=0."28 in diameter. The outer shell presents an hourglass--like morphology and exhibits a striking mirror symmetry with respect to its minor axis. The deduced mean electron densities are ~=1.2 x 104 cm-3 and ~=1.4 x 105 cm-3 in the outer and inner shells, respectively. The knots in the outer shell present electron densities of ~=3--4 x 104 cm-3, somewhat higher than the mean. The analysis of the H alpha , [N II], and [S II] emission lines, spatially and spectrally resolved in the spectrum, allows us to deduce the basic kinematical properties of the two shells. The outer shell presents bipolar motions, expands at ~=12 km s-1 in the equatorial plane, and was formed several hundred years ago. The inner shell expands at ~=25 km s-1 and was ejected some decades ago. The H alpha emission from the central star presents extremely wide wings that can be traced up to ~=5375 km s-1. This value is much higher than those previously reported for IC 4997. Our results suggest that the two shells are interacting and that a dense region may have been formed between the two shells. The physical conditions in this dense region could vary as the inner shell expands, and, therefore, variations of the emitted spectrum from this region are expected. This interaction should be taken into account in order to explain the observed variability of the emission lines in the nebula.

Miranda, Luis F.; Torrelles, Jose M.; Eiroa, Carlos

1996-04-01

88

Numerical simulations of thermal convection in a rapidly rotating spherical shell cooled inhomogeneously from above  

Microsoft Academic Search

Numerical simulations of thermal convection in a rapidly rotating spherical fluid shell with and without inhomogeneous temperature anomalies on the top boundary have been carried out using a three-dimensional, time-dependent, spectral-transform code. The spherical shell of Boussinesq fluid has inner and outer radii the same as those of the Earth's liquid outer core. The Taylor number is 107, the Prandtl

Zi-Ping Sun; Gerald Schubert; Gary A. Glatzmaier

1994-01-01

89

Distributed neural signals on parabolic cylindrical shells  

NASA Astrophysics Data System (ADS)

Parabolic cylindrical shells are commonly used as key components in communication antennas, space telescopes, solar collectors, etc. This study focuses on distributed modal neural sensing signals on a flexible simply-supported parabolic cylindrical shell panel. The parabolic cylindrical shell is fully laminated with a piezoelectric layer on its outer surface and the piezoelectric layer is segmented into infinitesimal elements (neurons) to investigate the microscopic distributed neural sensing signals. Since the dominant vibration component of the shell is usually the transverse oscillation, a new transverse mode shape function is defined. Two shell cases, i.e., the ratio of the meridian height to the half span distance of a parabola at 1:4 (shallow) and 1:1 (deep), are studied to reveal the curvature effect to the neural sensing signals. Studies suggest that the membrane signal component dominates for lower natural modes and the bending signal component dominates for higher natural modes. The meridional membrane and bending signal components are mostly concentrated on the high-curvature areas, while the longitudinal bending component is mostly concentrated on the relatively flat areas. The concentration behavior becomes more prominent as the parabolic cylindrical shell deepens, primarily resulting from the enhanced membrane effect due to the increased curvature.

Hu, S. D.; Li, H.; Tzou, H. S.

2013-06-01

90

HI in the shell elliptical NGC 3656  

E-print Network

VLA neutral hydrogen observations of the shell elliptical NGC 3656 reveal an edge-on, warped minor axis gaseous disk (M_HI ~ 2.10^9 Msun) extending 7 kpc. HI is also found outside the optical image, on two complexes to the North-East and North-West that seem to trace an outer broken HI disk or ring, or possibly one or two tidal tails. Integral-field optical fiber spectroscopy at the region of the bright southern shell of NGC 3656 has provided a determination of the stellar velocities of the shell. The shell has traces of HI with velocities bracketing the stellar velocities, providing evidence for a dynamical association of HI and stars at the shell. Within the errors the stars have systemic velocity, suggesting a possible phase wrapping origin for the shell. We detect five dwarf galaxies with HI masses ranging from 2.10^8 Msun to 2.10^9 Msun all within 180 kpc from NGC 3656 and all within the velocity range (450 \\kms) of the HI of NGC 3656. For the NGC 3656 group to be bound requires a total mass of 3-7.4x10^{12} Msun, yielding a mass to light ratio from 125 to 300. The overall HI picture presented by NGC 3656 supports the hypothesis of a disk-disk merger origin, or possibly an ongoing process of multiple merger with nearby dwarfs.

M. Balcells; J. H. van Gorkom; R. Sancisi; C. del Burgo

2001-07-09

91

HI in the shell elliptical NGC 3656  

E-print Network

VLA neutral hydrogen observations of the shell elliptical NGC 3656 reveal an edge-on, warped minor axis gaseous disk (M_HI ~ 2.10^9 Msun) extending 7 kpc. HI is also found outside the optical image, on two complexes to the North-East and North-West that seem to trace an outer broken HI disk or ring, or possibly one or two tidal tails. Integral-field optical fiber spectroscopy at the region of the bright southern shell of NGC 3656 has provided a determination of the stellar velocities of the shell. The shell has traces of HI with velocities bracketing the stellar velocities, providing evidence for a dynamical association of HI and stars at the shell. Within the errors the stars have systemic velocity, suggesting a possible phase wrapping origin for the shell. We detect five dwarf galaxies with HI masses ranging from 2.10^8 Msun to 2.10^9 Msun all within 180 kpc from NGC 3656 and all within the velocity range (450 \\kms) of the HI of NGC 3656. For the NGC 3656 group to be bound requires a total mass of 3-7.4x10^...

Balcells, M; Sancisi, R; Burgo, C

2001-01-01

92

Wear of hard materials by hard particles  

SciTech Connect

Hard materials, such as WC-Co, boron carbide, titanium diboride and composite carbide made up of Mo2C and WC, have been tested in abrasion and erosion conditions. These hard materials showed negligible wear in abrasion against SiC particles and erosion using Al2O3 particles. The WC-Co materials have the highest wear rate of these hard materials and a very different material removal mechanism. Wear mechanisms for these materials were different for each material with the overall wear rate controlled by binder composition and content and material grain size.

Hawk, Jeffrey A.

2003-10-01

93

Convective Transport in the Earth's Outer Radiation Belts  

NASA Astrophysics Data System (ADS)

Geomagnetic storms are typically characterized by strong magnetospheric convection due to sustained periods of southward IMF BZ. During periods of strong convection the Alfvén layer, which separates the region of sunward convection from closed drift shells, is displaced earthward allowing plasmasheet electrons with energies in the 100s of keV direct access inside of geosynchronous orbit. Subsequent outward motion of the Alfvén boundary and adiabatic energization during the storm recovery period trap plasmasheet electrons on closed drift shells providing a source population for the outer radiation belts. Van Allen Probe observations of the 8-10 October 2012 geomagnetic storm and MHD test-particle simulations illustrating the morphology of this process will be presented. Results demonstrate the potential for formation of strong peaks in electron phase space density inside of geosynchronous due to global dynamics of magnetospheric fields.

Kress, B. T.; Hudson, M. K.; Paral, J.

2013-12-01

94

Hardness testing. 2nd edition  

SciTech Connect

This basic book provides a comprehensive overview of hardness testing, including the various methods and equipment used, testing applications, and the selection of testing methods. The revised and updated second edition features expanded information on microhardness testing, specialized hardness tests; and hardness testing standards. Contents include: introduction to hardness testing; brinell testing; rockwell hardness testing; vickers hardness testing; microhardness testing; scleroscope and leeb hardness testing; hardness testing applications; and selection of hardness testing methods.

Chandler, H. [ed.

1999-07-01

95

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

2007-03-08

96

Outer Planets and Icy Satellites.  

National Technical Information Service (NTIS)

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 wat...

E. M. Drobyshevski

1991-01-01

97

Outer planets and icy satellites  

Microsoft Academic Search

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

E. M. Drobyshevski

1991-01-01

98

The Double-Shell Structure of the Variable Young Planetary Nebula IC 4997  

Microsoft Academic Search

VLA-A 3.6 cm continuum and H92 alpha observations and long-slit optical spectroscopy of IC 4997 are presented. The radio continuum map shows that IC 4997 is a double-shell planetary nebula consisting of a faint, knotty outer shell of size ~=2.\\

Luis F. Miranda; Jose M. Torrelles; Carlos Eiroa

1996-01-01

99

Strain history of ice shells of the Galilean satellites from radar detection of crystal orientation fabric  

E-print Network

Strain history of ice shells of the Galilean satellites from radar detection of crystal orientation of determining the subsurface thermal and physical structure of the outer ice I shells of the Galilean satellites. At radar frequencies, the dielectric permittivity of single and polycrystalline water ice I is anisotropic

Stillman, David E.

100

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

101

Discovery of hard X-ray features around hotspots of Cygnus A  

E-print Network

We present results of analysis of a Chandra observation of Cygnus A in which the X-ray hotspots at the ends of the jets are mapped in detail. A hardness map reveals previously unknown structure in the form of outer and inner hard arcs around the hotspots, with hardness significantly enhanced compared with the hotspot central regions. The outer hard arcs may constitute the first detection of the bow shock; the inner hard arcs may reveal where the jets impact on the hotspots. We argue that these features cannot result from electrons radiating by the synchrotron self-Compton process. Instead we consider two possible sources of the hard emission: the outer arcs may be due to thermal radiation of hot intracluster gas compressed at the bow shock. Alternatively, both outer and inner arcs may be due to synchrotron radiation of electrons accelerated in turbulent regions highly perturbed by shocks and shear flows. Comparison of measured hardness ratios with simulations of the hardness ratios resulting from these processes show that it is more diffcult to explain the observations with a thermal model. Although we cannot rule out a thermal model, we argue in favour of the non-thermal explanation. The hard regions in the secondary hotspots suggest that jet activity is still powering these hotspots.

M. Balucinska-Church; M. Ostrowski; L. Stawarz; M. J. Church

2004-11-17

102

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

103

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

104

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.

105

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

106

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

107

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

Federal Register 2010, 2011, 2012, 2013

...Regulation and Enforcement Outer Continental Shelf Official Protraction Diagram and Supplemental Official Outer Continental Shelf Block Diagrams AGENCY: Bureau...Datum of 1983 (NAD 83) Outer Continental Shelf Official Protraction...

2011-01-18

108

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

109

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

110

Modelling the influence of a translating inner core on outer core convection and the geodynamo  

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, suggesting a possible influence of inner core translation on outer core dynamics. The outer core is also likely subjected to lateral variations in heat-flux imposed from above by the convecting mantle. We use numerical models of nonmagnetic thermal convection in a rotating spherical shell to investigate possible long-term effects of inner core translation and mantle convection on the outer core. Solutions are obtained for Ekman number E = 10-5, Prandtl number Pr = 1 and Rayleigh numbers 2 - 30 times the critical value for different amplitudes of the boundary anomalies. Hemispheric inner boundary anomalies drive flows with lateral amplitude variations that are clearly visible in the time-average even when the imposed anomalies are significantly weaker than the average boundary heat-flux. Increasing the boundary forcing produces strong azimuthal jets that span large regions of the shell, while vigorous convection becomes confined to isolated regions that do not drift and always occur in the hemisphere subjected to a higher than average inner boundary heat-flux. Hemispheric outer boundary anomalies drive strong lateral flows near the top of the shell that weaken significantly with depth in all cases considered; convection near the base of the shell appears to be only weakly influenced by the outer boundary forcing. With hemispheric forcing on both boundaries the fluid response depends significantly on the phase relationship between the two patterns as well as the amplitudes of the respective anomalies. These results are used to explore the more complex situation of hemispheric inner boundary anomalies and outer boundary anomalies derived from lower mantle seismic tomography. Preliminary results suggest that, in the parameter range considered: 1) the effects of inner core translation are visible in the time-averaged flow at the outer boundary; 2) inner boundary heat-flux anomalies exert a greater overall influence on the spatio-temporal behaviour of the flow than outer boundary anomalies. Possible observational signatures of inner core translation will be further explored using geodynamo simulations.

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

2012-12-01

111

Microstructural Evolution of Hypoeutectic, Near-Eutectic, and Hypereutectic High-Carbon Cr-Based Hard-Facing Alloys  

NASA Astrophysics Data System (ADS)

A series of high-carbon Cr-based hard-facing alloys were successfully fabricated on a substrate of 0.45 pct C carbon steel by gas tungsten arc welding (GTAW) process using various alloy fillers with chromium and chromium carbide, CrC (Cr:C = 4:1) powders. These claddings were designed to observe hypoeutectic, near-eutectic, and hypereutectic structures with various (Cr,Fe)23C6 and (Cr,Fe)7C3 carbides at room temperature. According to X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and optical microscopy (OM), in 3.8 pct C cladding, the microstructure consisted of the primary carbides with outer shells (Cr,Fe)23C6 surrounding (Cr,Fe)7C3 cores and [ ? + (Cr,Fe)23C6] eutectic structures. In 5.9 pct C cladding, the composite comprised primary (Cr,Fe)7C3 as the reinforcing phase and [? + (Cr,Fe)7C3] eutectic structures as matrix. Various morphologies of carbides were found in primary and eutectic (Cr,Fe)7C3 carbides, which included bladelike and rodlike (with a hexagonal cross section). The 5.9C cladding with great amounts of primary (Cr,Fe)7C3 carbides had the highest hardness (approximately HRC 63.9) of the all conditions.

Lin, Chi-Ming; Chang, Chia-Ming; Chen, Jie-Hao; Hsieh, Chih-Chun; Wu, Weite

2009-05-01

112

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

113

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

114

Memory Hard Drive Peripherals  

E-print Network

1! CSI3131 Topics CPU Memory Hard Drive Peripherals Computing Systems OS Overview StructureDeadlocks M em ory M anagem ent Basic Memory Managermtn Virtual Memory Storage and I/O File Systems Hard Drive Management Swap I/O Management 2 Module 7: Memory Management Reading: Chapter 8 § To provide a detailed

Stojmenovic, Ivan

115

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

116

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.

Breslof, Lisa; Schiller, William

117

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

118

HI in the shell elliptical NGC 3656  

Microsoft Academic Search

VLA neutral hydrogen observations of the shell elliptical NGC 3656 reveal an\\u000aedge-on, warped minor axis gaseous disk (M_HI ~ 2.10^9 Msun) extending 7 kpc.\\u000aHI is also found outside the optical image, on two complexes to the North-East\\u000aand North-West that seem to trace an outer broken HI disk or ring, or possibly\\u000aone or two tidal tails.\\u000a Integral-field

Marc Balcells; J. H. van Gorkom; Renzo Sancisi; Carlos del Burgo

2001-01-01

119

An improved seed-mediated growth method to coat complete silver shells onto silica spheres for surface-enhanced Raman scattering  

Microsoft Academic Search

We synthesized SiO2@Ag core–shell particles with uniform and complete silver shells with an improved seed-mediated growth method. Silver nuclei produced on silica spheres with an electroless plating method served as nucleation sites for the growth of outer silver shells. By adjusting the Ag\\/SiO2 ratio, the thickness of silver shells was tuned, and the extinction peaks of SiO2@Ag particles shifted from

Tao Liu; Dongsheng Li; Deren Yang; Minhua Jiang

2011-01-01

120

Can Shells be Biomonitor of Contaminants in the Environment: an Investigation Study of Perfluorinated Compounds in Bivalve Shells of China  

NASA Astrophysics Data System (ADS)

To assess the feasibility of using biominerals to biomonitor the extent of persistent contaminants in the environment, concentrations of perfluorinated compounds (PFCs), including perfluorinated carboxylic acids (PFCAs) and perfluorinated alkylsulfonates (PFASs), in the bivalve shells of clams, razor clams, oysters and mussels sampled from 8 sampling sites along China coast were analyzed. Concentrations of these contaminants in the waters and sediments of the sampling sites, as well as in the soft tissues of clams were also determined. Results show that though the concentrations of most PFCs in shells were lower than in soft tissues, the amount of contaminants in shells and soft tissues of bivalves are comparable, due to the larger dry-weight of shells than soft tissues of these animals. Concentrations of some PFCs in shells primarily correlate to concentrations in sediments, while concentrations in the soft tissues seems to be more related to those in water samples. We suggested that shells uptake PFCs by adsorption or passive deposition of the target chemicals to the shell organic matrix followed by a biomineralisation process. Therefore, contaminants bound to the organic matrix in the shell microstructure are sequestrated and hard to release. Like soft tissues, biominerals, e.g. shells, might also be considered as biomonitoring matrix for some contaminants in environments, because (i) the individual differences of contaminants concentrations among shell samples were smaller than soft tissue samples; (ii) secondary pollution is less likely to affect shell samples during sampling and transportation; and (iii) the shells was hypothesized to "record" past exposure to contaminants according to their annual growth ring. (This study was supported by National Science Foundation for Natural Science, China (No. 20807024) & Research Fund for the Doctoral Program of Higher Education of China (No. 200800551051))

Wang, Lei

2010-05-01

121

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.

122

Manganese speciation in Diplodon chilensis patagonicus shells: a XANES study  

Microsoft Academic Search

In addition to other types of climate archives, biogenic skeletons of a variety of different organisms (i.e. shells of bivalves, skeletal hard parts of corals or sponges) are increasingly used for high-resolution climate reconstructions. Bivalves are particularly suited for such analyses because they are geographically broadly distributed and have been shown to record climate and environmental information reliably and over

A. L. Soldati; V. Vicente-Vilas; J. Goettlicher; D. E. Jacob

2009-01-01

123

Synthesis of the double-shell anatase-rutile TiO2 hollow spheres with enhanced photocatalytic activity  

NASA Astrophysics Data System (ADS)

A novel double-shell TiO2 hollow sphere with an inner anatase shell and an outer rutile shell was synthesized by a simple sol-gel method and silica protected calcination process. The structure and formation mechanism was proposed based on characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The double-shell spheres have a uniform diameter of 360 nm and a typical yolk-shell structure. Moreover, the double-shell TiO2 hollow spheres possess a large specific surface area (169 m2 g-1). Due to the high surface area, multiple light reflection and beneficial electron conduction between the inner anatase and outer rutile shell of this special structure, the as-prepared double-shell TiO2 catalysts show remarkably enhanced photoactivity compared to the commercial P25 catalyst. In particular, rhodamine B molecules can be completely decomposed in the presence of the double-shell spheres after 60 minutes of irradiation with UV light. In addition, the high activity is retained after five cycles, indicating the stability and reusability of the double-shell catalyst.A novel double-shell TiO2 hollow sphere with an inner anatase shell and an outer rutile shell was synthesized by a simple sol-gel method and silica protected calcination process. The structure and formation mechanism was proposed based on characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The double-shell spheres have a uniform diameter of 360 nm and a typical yolk-shell structure. Moreover, the double-shell TiO2 hollow spheres possess a large specific surface area (169 m2 g-1). Due to the high surface area, multiple light reflection and beneficial electron conduction between the inner anatase and outer rutile shell of this special structure, the as-prepared double-shell TiO2 catalysts show remarkably enhanced photoactivity compared to the commercial P25 catalyst. In particular, rhodamine B molecules can be completely decomposed in the presence of the double-shell spheres after 60 minutes of irradiation with UV light. In addition, the high activity is retained after five cycles, indicating the stability and reusability of the double-shell catalyst. Electronic supplementary information (ESI) available: UV-vis diffuse reflection spectra and the summarisation of BET surface and average pore size. See DOI: 10.1039/c3nr04043g

Li, Shunxing; Chen, Jie; Zheng, Fengying; Li, Yancai; Huang, Fuying

2013-11-01

124

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...General § 192.10 Outer continental shelf pipelines. Operators of...transportation pipelines on the Outer Continental Shelf (as defined in the Outer...

2010-10-01

125

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...General § 192.10 Outer continental shelf pipelines. Operators of...transportation pipelines on the Outer Continental Shelf (as defined in the Outer...

2011-10-01

126

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...General § 192.10 Outer continental shelf pipelines. Operators of...transportation pipelines on the Outer Continental Shelf (as defined in the Outer...

2012-10-01

127

Ideal strength of a Cu multi-shell nano-wire  

NASA Astrophysics Data System (ADS)

The ideal strength of a nano-component, which is the maximum stress of the structure, provides an insight into minute material. We conducted tensile simulations for a cylindrical-shaped Cu nano-wire composed of an atomic chain as a core wrapped around by shell(s) with the structure of (111) layers in a fcc crystal. Young's moduli and the ideal strengths of the wires are less than a single atomic chain and sheet. The mechanical strength of the wire is weakened by the following three factors: (a) changes in electron arrangement caused by combining core and shell; (b) a larger interatomic distance (inherent tensile strain) of the outer shell introduced for combining with the core chain; and (c) weak bonding (gap) on the outer shell caused by the mismatch of atomic layers due to the curvature difference. Factor (a) weakens the bonding of the shell(s) that occupy a greater part of the wire. A 5-1 wire, which consists of a core and a shell, is weakened compared with the single atomic chain and the single sheet due to (a) and (b). A 10-5-1 wire, consisting of a core and two shells, has less strength than a 5-1 wire due to (c) in addition to (a) and (b).

Kushima, A.; Umeno, Y.; Kitamura, T.

2006-09-01

128

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

129

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

130

Reactivation of outer-arm-depleted lung axonemes: evidence for functional differences between inner and outer dynein arms in situ.  

PubMed

Demembranated axonemes isolated from newt lung ciliated cells show a complex beat frequency response to varying [MgATP] and temperature [Hard and Cypher, 1992, Cell Motil. Cytoskeleton 21:187-198]. The present study was undertaken to ascertain whether the beat frequency of outer-arm-depleted newt lung axonemes is controlled in a manner similar to that of intact axonemes. Populations of demembranated ciliary axonemes were isolated by Triton X-100 extraction of lungs from the newt, Taricha granulosa. Aliquots of the demembranated axonemes were further treated with solutions containing high salt (0.375 M KC1) and 1.25 mM MgATP. This treatment resulted in the selective removal of outer dynein arms and a concomitant decrease in beat frequency to a stable level, 33-35% of control values. The effects of pH, salt concentration, nucleotides, and temperature on the beat frequency of reactivated outer-arm-depleted axonemes were ascertained and compared with those of intact axonemes. Some reactivation properties, such as nucleotide specificity, the effect of pH on beat frequency and the threshold [MgATP] required for reactivation (approximately 5 microM) were similar to those observed for intact axonemes. Other properties, such as the relationship between beat frequency and varying [MgATP] or salt concentration, differed both qualitatively and quantitatively from those of control axonemes, as did their response to temperature over the range, 5 degrees-32 degrees C. The nature of the results obtained with temperature and MgATP suggests that inner and outer dynein arms are not functionally equivalent in situ. PMID:1533820

Hard, R; Blaustein, K; Scarcello, L

1992-01-01

131

The outer wind of ? Velorum  

NASA Astrophysics Data System (ADS)

Fine-structure mid-infrared emission lines with critical densities in the regime 104 ? ncrit ? 106 cm-3 can be employed to probe the outflow from Wolf-Rayet (WR) stars at radii of ˜1015 cm. Narrow-band mid-infrared imaging and spectroscopy of the nearest WR star to the Sun, ? Velorum is analysed for spatially resolved forbidden line emission in the WR outer wind. The [S IV] 10.52-?m and [Ne II] 12.81-?m emission regions are found to be spatially extended, compared to unresolved continuum and He and C recombination line emission. The [S IV] and [Ne II] emission line distributions have a high degree of azimuthal symmetry, indicating a spherically symmetric outflow. A model wind with a modest degree of clumping (clumping factor f ˜ 10) provides a better match to the observations than an unclumped model. The overall line intensity distributions are consistent with a freely expanding, spherically symmetric 1/r2 outflow with constant ionization fraction and modestly clumped density structure.

Roche, P. F.; Colling, M. D.; Barlow, M. J.

2012-11-01

132

DI in the outer Galaxy  

E-print Network

We report on a deep search with the Westerbork Synthesis Radio Telescope towards the galactic anticenter for the 327 MHz hyperfine transition of DI. This is a favorable direction for a search because: (i) the HI optical depth is high due to velocity crowding; (ii) the observed molecular column density is low (implying that most of the deuterium would probably be in atomic form, rather than in HD); and (iii) the stellar reprocessing should be minimal. Our observations are about a factor of two more sensitive than previous searches for DI in this direction. We detect a low significance (about 4 sigma) feature, consistent in both amplitude and center frequency with an emission feature reported previously (Blitz & Heiles 1987). If this is the DI line, then the implied N_D/N_H of 3.9+/-1.0 x 10^-5 is comparable to the inferred pre-solar deuterium abundance. Our observation is consistent with the recent low measurements of D/H towards high-redshift Lyman-limit systems. On the other hand, if the reports of high DI abundance (about 24 x 10^-5) in such systems are confirmed, then our observations imply that even in regions of reduced star formation within the outer Galaxy, the DI abundance has been reduced by a factor of about 6 from the primordial abundance.

Jayaram N. Chengalur; Robert Braun; W. Butler Burton

1997-01-13

133

Hard superconducting nitrides  

PubMed Central

Detailed study of the equation of state, elasticity, and hardness of selected superconducting transition-metal nitrides reveals interesting correlations among their physical properties. Both the bulk modulus and Vickers hardness are found to decrease with increasing zero-pressure volume in NbN, HfN, and ZrN. The computed elastic constants from first principles satisfy c11 > c12 > c44 for NbN, but c11 > c44 > c12 for HfN and ZrN, which are in good agreement with the neutron scattering data. The cubic ?-NbN superconducting phase possesses a bulk modulus of 348 GPa, comparable to that of cubic boron nitride, and a Vickers hardness of 20 GPa, which is close to sapphire. Theoretical calculations for NbN show that all elastic moduli increase monotonically with increasing pressure. These results suggest technological applications of such materials in extreme environments. PMID:15728352

Chen, Xiao-Jia; Struzhkin, Viktor V.; Wu, Zhigang; Somayazulu, Maddury; Qian, Jiang; Kung, Simon; Christensen, Axel N?rlund; Zhao, Yusheng; Cohen, Ronald E.; Mao, Ho-kwang; Hemley, Russell J.

2005-01-01

134

Specialized shell-breaking crab claws in Cretaceous seas.  

PubMed

Here we report on a large brachyuran crab species from the Late Cretaceous of Mexico that has claws indicative of highly specialized shell-breaking behaviour. This crab possessed dimorphic claws (the right larger than the left), armed with several broad teeth, including a curved tooth structure found at the base of the movable finger of the right claw. The curved tooth is similar to the one observed on claws of many living durophagous crabs that use it as a weapon to peel, crush or chip the edges of hard-shelled prey, particularly molluscs. These morphological traits suggest that specialized shell-breaking crab predators had evolved during the Cretaceous, which contradicts previous findings supporting an Early Cenozoic origin for specialized shell crushers within the brachyuran clade. PMID:18331975

Dietl, Gregory P; Vega, Francisco J

2008-06-23

135

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

136

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

137

Resonant structure of the outer asteroid belt  

Microsoft Academic Search

An analysis of ordered and chaotic regions of motion in the outer asteroid belt has shown that once the eccentricity of Jupiter is introduced the chaotic regions of the circular model are quite easily depleted. This suggests that also objects in neighbouring regions must be strongly perturbed. Therefore it is not surprising that many outer belt asteroids have been reported

Andrea Milani; Anna M. Nobili

1984-01-01

138

Interiors and atmospheres of the outer planets  

NASA Technical Reports Server (NTRS)

This theoretical/observational project constrains structure of outer planet atmospheres and interiors through observational data. The primary observation tool is through observations of occultations of stars by outer solar system objects, which yield information about atmospheric temperatures and dynamics, and planetary dimensions and oblateness. The theoretical work relates the data to interior structures in a variety of ways.

Hubbard, W. B.

1991-01-01

139

Elbow and knee joint for hard space suits  

NASA Technical Reports Server (NTRS)

An elbow or knee joint for a hard space suit or similar usage is formed of three serially connected rigid sections which have truncated spherical configurations. The ends of each section form solid geometric angles, and the sections are interconnected by hermetically sealed ball bearings. The outer two sections are fixed together for rotation in a direction opposite to rotation of the center section. A preferred means to make the outer sections track each other in rotation comprises a rotatable continuous bead chain which engages sockets circumferentially spaced on the facing sides of the outer races of the bearings. The joint has a single pivot point and the bearing axes are always contained in a single plane for any articulation of the joint. Thus flexure of the joint simulates the coplanar flexure of the knee or elbow and is not susceptible to lockup.

Vykukal, H. C.

1986-01-01

140

Synthesis and characterization of hard/soft bimagnetic nanoparticles  

NASA Astrophysics Data System (ADS)

Bimagnetic nanoparticles are synthesized from high-temperature solution method by growing soft magnetic phases on a hard magnetic phase. The hard phase is chosen as the FePt phase and the soft phases include Fe3O4, CoFe2O4 and FeCo. The soft phases can be coated or attached to the hard phase by changing reaction conditions. When the soft phases are coated on the hard phase, core/shell structured bimagnetic nanoparticles are formed; when the soft phases are attached to the hard phase, brick-like bimagnetic nanoparticles are formed. Magnetic properties of these nanoparticles are affected by dimensions of the soft and hard components due to the exchange coupling between them. Upon reductive annealing, an assembly of the bimagnetic nanoparticles is transformed into a hard magnetic nanocomposite with enhanced energy product which is 35% higher than single FePt phase. With proper choice of materials and dimension of both phases, these bimangetic nanoparticles may be used as building blocks for novel functional nanomaterials for various applications.

Nandwana, Vikas; Shankar Chaubey, Girija; Yano, Kazuaki; Liu, J. Ping

2007-03-01

141

H I in the Shell Elliptical Galaxy NGC 3656  

Microsoft Academic Search

Very Large Array7 neutral hydrogen observations of the shell elliptical galaxy NGC 3656 reveal an edge-on, warped minor-axis gaseous disk (MHI~2×109 Msolar) extending 7 kpc. H I is also found outside the optical image, on two complexes to the northeast and northwest that seem to trace one or two tidal tails, or possibly an outer broken H I disk or

Marc Balcells; J. H. van Gorkom; Renzo Sancisi; Carlos del Burgo

2001-01-01

142

Name That Shell  

NSDL National Science Digital Library

The way a firework shell is designed and assembled determines the shape and color of a firework display. Choose a video clip and try to identify each firework variety in this interactive activity from the NOVA Web site.

Foundation, Wgbh E.

2004-01-29

143

Holographic gravitational infall in the hard wall model  

NASA Astrophysics Data System (ADS)

An infalling shell in the hard wall model provides a simple holographic model for energy injection in a confining gauge theory. Depending on its parameters, a scalar shell either collapses into a large black brane, or scatters between the hard wall and the anti-de Sitter boundary. In the scattering regime, we find numerical solutions that keep oscillating for as long as we have followed their evolution, and we provide an analytic argument that shows that a black brane can never be formed. This provides examples of states in infinite-volume field theory that never thermalize. We find that the field theory expectation value of a scalar operator keeps oscillating, with an amplitude that undergoes modulation.

Craps, Ben; Lindgren, E. J.; Taliotis, Anastasios; Vanhoof, Joris; Zhang, Hongbao

2014-10-01

144

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

145

Generating Hard Satisfiability Problems  

Microsoft Academic Search

We report results from large-scale experiments in satisfiability testing. As has been observed by others, testing the satisfiability of random formulas often appears surprisingly easy. Here we show that by using the right distribution of instances, and appropriate parameter valu es, it is possible to generate random formulas that are hard, that is, for which satisfiability testing is quite difficult.

Bart Selman; David G. Mitchell; Hector J. Levesque

1996-01-01

146

Hard Sphere Gas Model  

NSDL National Science Digital Library

The Ejs Hard Sphere Gas model displays a three-dimensional (ideal) gas made out of hard disks. Particles are initialized with a random speed and in a random direction and move with constant velocity until a collision occurs. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Hard Sphere Gas model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_newton_HardShpereGas.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for statistical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-06

147

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

148

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

149

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

150

Stable carbon isotopes in freshwater mussel shells: Environmental record or marker for metabolic activity?  

NASA Astrophysics Data System (ADS)

Mussel shells have been used in a number of paleoecological and environmental studies. The interpretation of stable carbon isotopic composition of shell material is still controversial. The carbon for shell carbonate precipitation can either be derived from ambient dissolved inorganic carbon (DIC), with shells recording environmental signals, or from metabolic CO 2, with the potential to disguise environmental signals. To gain insight into this question, we investigated four nearly 100-yr long-term records of aragonite shells from an extant freshwater bivalve species, the endangered freshwater pearl mussel ( Margaritifera margaritifera L.). Single growth increments of the outer prismatic and the inner nacreous zones were successfully and easily separated with a simple heat treatment for chronological analyses of ? 13C in single layers of each zone. Autocorrelation and semivariance statistical methods reveal that mussels show distinct individual signal patterns, which extend up to 25 yr. Signal patterns are reliably reproduced with replicate samples from defined layers within one shell and show similar patterns with a slight offset for inner nacreous and outer prismatic layers for individual animals. Mussels exposed to the same environmental conditions exhibit distinct and contradictory signature patterns, which do not match between individuals. This observation can only be explained by strong metabolic influences on shell precipitation. Environmental changes in pH, temperature, electric conductivity and atmospheric carbon signature had no or little (<5%) influence, whereas body tissue protein and body tissue ? 13C signatures negatively correlated with the youngest produced shell ? 13C signatures, indicating that respiration causes a preferential loss of light isotopes from body mass and an inverse enrichment in shell aragonite. Hence, the shells of the freshwater pearl mussel yield a long-term record of metabolic activity, whereas the use of ? 13C in these shells as recorder for environmental signals is questionable. This may also be true for shells from other species, for which metabolic carbon incorporation has been acknowledged.

Geist, Juergen; Auerswald, Karl; Boom, Arnoud

2005-07-01

151

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

152

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

153

Outer planets and icy satellites  

NASA Astrophysics Data System (ADS)

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.

154

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

155

A rigid and weathered ice shell on Titan.  

PubMed

Several lines of evidence suggest that Saturn's largest moon, Titan, has a global subsurface ocean beneath an outer ice shell 50 to 200?kilometres thick. If convection is occurring, the rigid portion of the shell is expected to be thin; similarly, a weak, isostatically compensated shell has been proposed to explain the observed topography. Here we report a strong inverse correlation between gravity and topography at long wavelengths that are not dominated by tides and rotation. We argue that negative gravity anomalies (mass deficits) produced by crustal thickening at the base of the ice shell overwhelm positive gravity anomalies (mass excesses) produced by the small surface topography, giving rise to this inverse correlation. We show that this situation requires a substantially rigid ice shell with an elastic thickness exceeding 40 kilometres, and hundreds of metres of surface erosion and deposition, consistent with recent estimates from local features. Our results are therefore not compatible with a geologically active, low-rigidity ice shell. After extrapolating to wavelengths that are controlled by tides and rotation, we suggest that Titan's moment of inertia may be even higher (that is, Titan may be even less centrally condensed) than is currently thought. PMID:23985871

Hemingway, D; Nimmo, F; Zebker, H; Iess, L

2013-08-29

156

Hard Copy Market Overview  

NASA Astrophysics Data System (ADS)

A number of Color Hard Copy (CHC) market drivers are currently indicating strong growth in the use of CHC technologies for the business graphics marketplace. These market drivers relate to product, software, color monitors and color copiers. The use of color in business graphics allows more information to be relayed than is normally the case in a monochrome format. The communicative powers of full-color computer generated output in the business graphics application area will continue to induce end users to desire and require color in their future applications. A number of color hard copy technologies will be utilized in the presentation graphics arena. Thermal transfer, ink jet, photographic and electrophotographic technologies are all expected to be utilized in the business graphics presentation application area in the future. Since the end of 1984, the availability of color application software packages has grown significantly. Sales revenue generated by business graphics software is expected to grow at a compound annual growth rate of just over 40 percent to 1990. Increased availability of packages to allow the integration of text and graphics is expected. Currently, the latest versions of page description languages such as Postscript, Interpress and DDL all support color output. The use of color monitors will also drive the demand for color hard copy in the business graphics market place. The availability of higher resolution screens is allowing color monitors to be easily used for both text and graphics applications in the office environment. During 1987, the sales of color monitors are expected to surpass the sales of monochrome monitors. Another major color hard copy market driver will be the color copier. In order to take advantage of the communications power of computer generated color output, multiple copies are required for distribution. Product introductions of a new generation of color copiers is now underway with additional introductions expected during 1987. The color hard copy market continues to be in a state of constant change, typical of any immature market. However, much of the change is positive. During 1985, the color hard copy market generated 1.2 billion. By 1990, total market revenue is expected to exceed 5.5 billion. The business graphics CHC application area is expected to grow at a compound annual growth rate greater than 40 percent to 1990.

Testan, Peter R.

1987-04-01

157

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

158

Depletion of the Outer Asteroid Belt  

PubMed

During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region. PMID:8994031

Liou; Malhotra

1997-01-17

159

Geographic variation of shell bionts in the deep-sea snail Gaza  

NASA Astrophysics Data System (ADS)

Recent studies of bathyal environments indicate that microhabitats contribute significantly to biodiversity. We suggest that microhabitats may also be useful in direct comparisons of biotic diversity patterns across large areas. Using a technique developed by palaeontologists, we document the diversity and abundance of taxa occurring on the hard substrate provided by gastropod shells of the bathyal (200 m) trochid gastropod Gaza. Because the shell surfaces are comparable, shell-associated biota and their diversity may be contrasted across basins with relatively few compounding variables. Animals found attached to the outside of the shells, epibionts, included folliculinids, encrusting bryozoans and foraminifera; within the shell, endobiontic spionid polychaetes had occupied the columella of the shell, apparently destroying both the protoconch and part of the shell's base. Both types of bionts were common on shells from continental margins of North and South America but were wholly absent on shells from the Lesser Antilles. Hypotheses that shell depth distributions (372-910 m) and shell age, biont dispersal potential and biotic interactions contribute to the large-scale differences in biont distribution are considered but rejected in favour of the hypothesis that terrigenous sediments and their associated nutrients are primary contributors to the observed geographic pattern.

Voight, Janet R.; Walker, Sally E.

1995-08-01

160

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

161

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

162

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

163

Review of recovery and recolonization of hard substrate communities of the Outer Continental Shelf. Final report  

SciTech Connect

This report summarizes knowledge of how marine benthic communities off California respond to both natural and anthropogenic disturbances. The results from the study will aid the MMS in making environmental assessments and management decisions associated with potential oil and gas leasing, exploration, and development activities. The objectives of the report on recovery and recolonization are: (1) to review relevant recovery and recolonization studies, pertinent life-history information, and data gaps.

Lissner, A.

1988-06-01

164

Branes in Supernova Shells  

E-print Network

This paper is firstly intended to review shortly the most recent developments and ideas resulting from the necessity of having a scale at which gravitation to unify the other fundamental forces. With the declared intention of predicting an {\\it in situ} distinct possibility for Kaluza-Klein gravitons formation in the supernova shell we are using state of the art simulations \\citep{langer,ud1,ud2,ud3} for massive stellar winds to infer that the supernova shock which will hit such winds will meet a non-isotropic and non-homogeneous matter distribution with a very distinct geometry. By linking this to the mechanism of particle shock acceleration at cosmic ray energies (Fermi acceleration) and the related spallation in the wind shell, the result is the creation of proper conditions for Kaluza-Klein gravitons formation in the supernova shell from neutrino secondary particles (cosmic ray spallation products) interacting with $\\sim 10^{18}$ eV cosmic rays.

A. S. Popescu

2005-05-25

165

Statistical theory of correlations in random packings of hard particles  

NASA Astrophysics Data System (ADS)

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), ?rcp=0.85±0.01, and random loose packing (RLP), ?rlp=0.67±0.01. Our theory also predicts a phase diagram and angular correlation functions that are in good agreement with experimental and numerical data.

Jin, Yuliang; Puckett, James G.; Makse, Hernán A.

2014-05-01

166

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

167

75 FR 1076 - Outer Continental Shelf Civil Penalties  

Federal Register 2010, 2011, 2012, 2013

...Minerals Management Service Outer Continental Shelf Civil Penalties AGENCY: Minerals...SUMMARY: The Outer Continental Shelf Lands Act requires the MMS to...gas operations in the Outer Continental Shelf at least once every 3...

2010-01-08

168

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... General § 195.9 Outer continental shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf must identify...

2010-10-01

169

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... General § 195.9 Outer continental shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf must identify...

2012-10-01

170

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... General § 195.9 Outer continental shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf must identify...

2011-10-01

171

Radial variations in modulus and hardness in SCS-6 silicon carbide fibers  

SciTech Connect

The mechanical properties of SCS-6 SiC fibers were measured as a function of fiber radius using nanoindentation techniques. Hardness and Young`s modulus were characterized for the material in all of the major regions of these fibers: the carbon core, the graphitic core coating, the inner SiC sheath, and the outer SiC sheath. The carbon core of the fibers was determined to be uniform in properties but extremely compliant. Young`s modulus of 28 GPa and a hardness of 4.2 GPa were measured. The graphitic core coating was found to exhibit considerable anelasticity and to have both a low modulus (21 GPa) and a low hardness (1.7 GPa). The inner sheath of the fiber, which contained a varying chemistry, showed a sharp increase in stiffness and hardness from the inner core. Modulus and hardness increased by an order of magnitude over just 1 or 2 {micro}m when transversing radially away from the core into the SiC. This change in properties was pronounced and clearly defined. The outer sheath, which contained a uniform chemistry and microstructure, was consistently stiff and hard when transversing radially. The average modulus and hardness for the full fiber was 333 GPa. The values reported for Young`s modulus and hardness clearly showed that the mechanical properties of SCS SiC fibers exhibit dramatic changes across their diameters.

Mann, A.B.; Weihs, T.P. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Materials Science and Engineering; Balooch, M.; Kinney, J.H. [Lawrence Livermore National Lab., CA (United States). Dept. of Chemistry and Materials Science

1999-01-01

172

Project EARTH-12-SHELL4: Shell Geoscience Laboratory  

E-print Network

) This studentship is funded by Shell and is part of a larger Shell-supported research project on shale-gas shale in many conventional hydrocarbon seals, and they may also be a factor in shale gas reservoirs. Whilst

Henderson, Gideon

173

Oyster shell conveyor used to lift shells from the dock ...  

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

Oyster shell conveyor used to lift shells from the dock into the receiving room housed in the 1965 concrete block addition. - J.C. Lore Oyster House, 14430 Solomons Island Road, Solomons, Calvert County, MD

174

Uranyl peroxide oxalate cage and core-shell clusters containing 50 and 120 uranyl ions.  

PubMed

Cage clusters built from uranyl hexagonal bipyramids and oxalate ligands crystallize from slightly acidic aqueous solution under ambient conditions, facilitating structure analysis. Each cluster contains uranyl ions coordinated by peroxo ligands in a bidentate configuration. Uranyl ions are bridged by shared peroxo ligands, oxalate ligands, or through hydroxyl groups. U(50)Ox(20) contains 50 uranyl ions and 20 oxalate groups and is a topological derivative of the U(50) cage cluster that has a fullerene topology. U(120)Ox(90) contains 120 uranyl ions and 90 oxalate groups and is the largest and highest mass cluster containing uranyl ions that has been reported. It has a core-shell structure, in which the inner shell (core) consists of a cluster of 60 uranyl ions and 30 oxalate groups, identical to U(60)Ox(30), with a fullerene topology. The outer shell contains 12 identical units that each consist of five uranyl hexagonal bipyramids that are linked to form a ring (topological pentagon), with each uranyl ion also coordinated by a side-on nonbridging oxalate group. The five-membered rings of the inner and outer shells (the topological pentagons) are in correspondence and are linked through K cations. The inner shell topology has therefore templated the location of the outer shell rings, and the K counterions assume a structure-directing role. Small-angle X-ray scattering data demonstrated U(50)Ox(20) remains intact in aqueous solution upon dissolution. In the case of clusters of U(120)Ox(90), the scattering data for dissolved crystals indicates the U(60)Ox(30) core persists in solution, although the outer rings of uranyl bipyramids contained in the U(120)Ox(90) core-shell cluster appear to detach from the cluster when crystals are dissolved in water. PMID:22296269

Ling, Jie; Qiu, Jie; Burns, Peter C

2012-02-20

175

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

176

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.

2012-10-12

177

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 wt % boron carbide and the remainder a metal mixture comprising from 70 to 90% 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 and 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

Sheinberg, H.

1983-07-26

178

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

179

Lab-in-a-shell: encapsulating metal clusters for size sieving catalysis.  

PubMed

Here we describe a lab-in-a-shell strategy for the preparation of multifunctional core-shell nanospheres consisting of a core of metal clusters and an outer microporous silica shell. Various metal clusters (e.g., Pd and Pt) were encapsulated and confined in the void space mediated by the entrapped polymer dots inside hollow silica nanospheres acting first as complexing agent for metal ions and additionally as encapsulator for clusters, limiting growth and suppressing the sintering. The Pd clusters encapsulated in hybrid core-shell structures exhibit exceptional size-selective catalysis in allylic oxidations of substrates with the same reactive site but different molecular size (cyclohexene ?0.5 nm, cholesteryl acetate ?1.91 nm). The solvent-free aerobic oxidation of diverse hydrocarbons and alcohols was further carried out to illustrate the benefits of such an architecture in catalysis. High activity, outstanding thermal stability and good recyclability were observed over the core-shell nanocatalyst. PMID:25075561

Qiao, Zhen-An; Zhang, Pengfei; Chai, Song-Hai; Chi, Miaofang; Veith, Gabriel M; Gallego, Nidia C; Kidder, Michelle; Dai, Sheng

2014-08-13

180

Nuclear Shell Models  

Microsoft Academic Search

The principal features of the several shell models now under discussions are described briefly. The magnetic moments of odd nuclei have been interpreted as (a) supporting an extreme single particle model (Schmidt limits) and (b) as generally consistent with a uniform model (Margenau-Wigner limits). The evidence is consistent with a composite interpretation based on (a) the approximate validity of the

Eugene Feenberg

1950-01-01

181

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

182

Shell Higher Olefins Process.  

ERIC Educational Resources Information Center

Shows how olefin isomerization and the exotic olefin metathesis reaction can be harnessed in industrial processes. Indicates that the Shell Higher Olefins Process makes use of organometallic catalysts to manufacture alpha-olefins and internal carbon-11 through carbon-14 alkenes in a flexible fashion that can be adjusted to market needs. (JN)

Lutz, E. F.

1986-01-01

183

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

184

Exergetic optimization of shell and tube heat exchangers using a genetic based algorithm  

Microsoft Academic Search

In the computer-based optimization, many thousands of alternative shell and tube heat exchangers may be examined by varying the high number of exchanger parameters such as tube length, tube outer diameter, pitch size, layout angle, baffle space ratio, number of tube side passes.In the present study, a genetic based algorithm was developed, programmed, and applied to estimate the optimum values

Yavuz Özçelik

2007-01-01

185

P. Palazzi -Meson Shells Page 1 of 14 p3a-2005-001  

E-print Network

in a variety of partially charged "ionic" patterns related to JPC and the quark content. This hypothesis of 14 1. Introduction Quarks and their mixing are the cornerstone of particle physics. Essential of the electrons of the outer shell. Following the original formulation of the quarks ­ and of the hypothesis

186

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

187

Palaeoecology and evolution of marine hard substrate communities  

NASA Astrophysics Data System (ADS)

Marine organisms have occupied hard substrates since the Archaean. Shells, rocks, wood and sedimentary hardgrounds offer relatively stable habitats compared to unconsolidated sediments, but the plants and animals which inhabit them must develop means to gain and defend this premium attachment space. Hard substrate communities are formed by organisms with a variety of strategies for adhering to and/or excavating the substrates they inhabit. While mobile grazers, organically attached and even soft-bodied organisms may leave evidence of their former presence in ancient hard substrate communities, a superior fossil record is left by sessile encrusters with mineralised skeletons and by borers which leave trace fossils. Furthermore, encrusters and borers are preserved in situ, retaining their spatial relationships to one another and to the substrate. Spatial competition, ecological succession, oriented growth, and differential utilisation of exposed vs. hidden substrate surfaces can all be observed or inferred. Hard substrate communities are thus excellent systems with which to study community evolution over hundreds of millions of years. Here we review the research on modern and ancient hard substrate communities, and point to some changes that have affected them over geological time scales. Such changes include a general increase in bioerosion of hard substrates, particularly carbonate surfaces, through the Phanerozoic. This is, at least in part, analogous to the infaunalisation trends seen in soft substrate communities. Encrusting forms show an increase in skeletalisation from the Palaeozoic into the Mesozoic and Cenozoic, which may be a response to increasing levels of predation. Hard substrate communities, considering borers and encrusters together, show a rough increase in tiering through the Phanerozoic which again parallels trends seen in soft substrate communities. This extensive review of the literature on living and fossil hard substrate organisms shows that many opportunities remain for large-scale studies of trends through time at the community and clade levels. Palaeontologists will especially benefit by closer integration of their work with that of neontologists, particularly in aspects of ecology such as larval recruitment, competition and succession.

Taylor, P. D.; Wilson, M. A.

2003-07-01

188

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

189

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

190

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.

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

2014-01-01

191

Baseline Microstructural Characterization of Outer 3013 Containers  

SciTech Connect

Three DOE Standard 3013 outer storage containers were examined to characterize the microstructure of the type 316L stainless steel material of construction. Two of the containers were closure-welded yielding production-quality outer 3013 containers; the third examined container was not closed. Optical metallography and Knoop microhardness measurements were performed to establish a baseline characterization that will support future destructive examinations of 3013 outer containers in the storage inventory. Metallography revealed the microstructural features typical of this austenitic stainless steel as it is formed and welded. The grains were equiaxed with evident annealing twins. Flow lines were prominent in the forming directions of the cylindrical body and flat lids and bottom caps. No adverse indications were seen. Microhardness values, although widely varying, were consistent with annealed austenitic stainless steel. The data gathered as part of this characterization will be used as a baseline for the destructive examination of 3013 containers removed from the storage inventory.

Zapp, Phillip E.; Dunn, Kerry A

2005-07-31

192

MHD processes in the outer heliosphere  

NASA Technical Reports Server (NTRS)

The magnetic field measurements from Voyager and the magnetohydrodynamic (MHD) processes in the outer heliosphere are reviewed. A bibliography of the experimental and theoretical work concerning magnetic fields and plasmas observed in the outer heliosphere is given. Emphasis in this review is on basic concepts and dynamical processes involving the magnetic field. The theory that serves to explain and unify the interplanetary magnetic field and plasma observations is magnetohydrodynamics. Basic physical processes and observations that relate directly to solutions of the MHD equations are emphasized, but obtaining solutions of this complex system of equations involves various assumptions and approximations. The spatial and temporal complexity of the outer heliosphere and some approaches for dealing with this complexity are discussed.

Burlaga, L. F.

1984-01-01

193

Hardness, strength, and ductility of prefabricated titanium rods used in the manufacture of spark erosion crowns  

Microsoft Academic Search

Depending on the size of the prepared tooth spark eroded and milled, Procera crowns (Nobelpharma AB, Göteborg, Sweden) are manufactured from one of five diameters of pure titanium rods. In this study microindentation hardness tests were performed on the outer 400 ?m and center of 10 samples for each type of rod. Five tensile samples were also machined for each

Einar Berg; Geir Davik; Trond Hegdahl; Nils Roar Gjerdet

1996-01-01

194

A Study of the Valence Shell Photoelectron and Photoabsorption Spectra of CF?SF?  

SciTech Connect

The outer valence shell photoelectron spectrum of CF?SF? has been studied experimentally and theoretically. Synchrotron radiation has been used to record angle resolved outer valence shell photoelectron spectra of CF?SF? in the photon energy range 18-60 eV. These spectra have allowed photoelectron asymmetry parameters and branching ratios to be derived. The Outer Valence Green’s Function approach has been employed to calculate the molecular orbital configuration and associated binding energies. A charge distribution analysis has also been obtained. Assignments have been proposed for the peaks observed in the photoelectron spectrum. The absolute photoabsorption cross section of CF?SF? has been measured from threshold to 40 eV, and strongly resembles that of SF6. Assignments, involving intravalence transitions, have been proposed for some of the principal features appearing in the photoabsorption spectrum of CF?SF?.

Holland, David M. P.; Shaw, David; Walker, I.C.; McEwen, I. C.; Apra, Edoardo; Guest, Martyn F.

2005-06-28

195

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

196

Outer planet probe cost estimates: First impressions  

NASA Technical Reports Server (NTRS)

An examination was made of early estimates of outer planetary atmospheric probe cost by comparing the estimates with past planetary projects. Of particular interest is identification of project elements which are likely cost drivers for future probe missions. Data are divided into two parts: first, the description of a cost model developed by SAI for the Planetary Programs Office of NASA, and second, use of this model and its data base to evaluate estimates of probe costs. Several observations are offered in conclusion regarding the credibility of current estimates and specific areas of the outer planet probe concept most vulnerable to cost escalation.

Niehoff, J.

1974-01-01

197

Ptolemy's treatment of the outer planets  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to investigate whether for the outer planets Ptolemy followed his otherwise consistent custom of describing a scenario that did not happen as he says, or whether, at least for the outer planets, he left us a more accurate rendition of events. The detailed reconstructions of Ptolemy's calculations that follow show that, at least in the Almagest, Ptolemy is a writer with consistent habits when it comes to observations. We begin by reviewing, with minimal editorial comment, Ptolemy's calculations for each planet.

Duke, Dennis

2005-01-01

198

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

199

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

200

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

201

First Images from HERO, a Hard X-Ray Focusing Telescope  

NASA Astrophysics Data System (ADS)

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 unprecedented sensitivity in the hard X-ray region and will achieve millicrab-level sensitivity in a typical 3 hr balloon-flight observation and 50 ?crab sensitivity on ultralong-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.; O'Dell, Stephen L.; Speegle, Chet O.; Swartz, Douglas A.; Weisskopf, Martin C.

2002-03-01

202

IRAC Near-Infrared Features in the Outer Parts of S4G Galaxies  

E-print Network

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 R_25) 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 per pixel at 3.6 microns 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 asymmetri...

Laine, Seppo; Munoz-Mateos, Juan-Carlos; Kim, Taehyun; Comeron, Sebastien; 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; Menendez-Delmestre, Karin; 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

2014-01-01

203

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

204

The Shell Island Dilemma  

NSDL National Science Digital Library

The objective of this inquiry simulation is to investigate the issues concerning the fate of the Shell Island Resort, which is in danger of being destroyed by a migrating inlet, and then debate the future of this and other oceanfront structures threatened by coastal erosion. As students engage in their investigation, they are asked to identify the social, political, and scientific issues with which different stakeholders must deal. They will place themselves into the role of one of the stakeholders. The site lists the stakeholders and provides several sources of information for each. After reviewing the resources, students will prepare a statement to decide what should be the next course of action regarding the Shell Island Resort. Students then will present statements in a debate to decide the future of the resort.

205

Thermomechanical Postbuckling of Shells  

NASA Technical Reports Server (NTRS)

A number of issues involving the postbuckling of doubly-curved panels exposed to a non-uniform temperature field and subjected to a system of mechanical loads are considered in this paper. Effects played by transverse shear, initial geometric imperfections, membrane and thickness-wise temperature gradient, tangential edge constraints, linear/non-linear elastic foundation are incorporated and their implications on the non-linear response behavior of shells are discussed. Issues related with the delay of the occurrence of the snap-through buckling, alleviation of its intensity and even with its removal are addressed and remarks on conditions rendering a curved panel insensitive to initial geometric imperfections are included. Results on small vibration of shells about sub- and post-critical ranges are provided and structural modeling issues playing a non-negligible role towards a reliable prediction of the postbuckling behavior of shells under complex loading conditions are discussed. Results on non-linear response of flat reinforced panels subjected to thermomechanical loads are also presented. Finally, problems not covered by this article are briefly indicated.

Librescu, Liviu

1998-01-01

206

Golden Rule of Radiation Hardness: a Study of Strain Effect on Controlled Radiation Damage  

NASA Astrophysics Data System (ADS)

Stain is widely presented in microstructures. Strain effect to radiation hardness is critical in understanding and engineering nano-materials. Here we studied the strain effect on the controlled radiation damage in monolayer hexagonal boron nitride (h-BN) through ab initio density functional theory calculations. We observed a general behavior of reduction in the radiation hardness by the strain, for both B-vacancy and N-vacancy configurations, in both compressive and tensive strain states, at the directions of zigzag, armchair and bi-axial. We proposed a golden rule of the radiation hardness states that any effort adding energy to the system will reduce the radiation hardness. Such golden rule of radiation hardness could be widely applied to material design and engineering for those devices working in irradiation-enrich environments, for example, electronic and optoelectronic devices in outer space.

Peng, Qing; Ji, Wei; de, Suvranu

2012-02-01

207

[Chemistry in Outer Solar System and Beyond  

NASA Technical Reports Server (NTRS)

During the three years of the NASA Planetary Atmospheres grant NAG51 1032, we have developed photochemical models for Jupiter, Saturn, Uranus, Neptune, Io, and extrasolar giant planets. We have compared the Io and outer planet model predictions with various infrared and microwave observations.

2004-01-01

208

Outer Seal for First Stage Turbine.  

National Technical Information Service (NTIS)

The patent relates to an outer air seal for the first stage turbine of an engine having the seal segments made of a high strength base material with a highly oxidation-corrosion resistant abradable alloy layer bonded to the surface thereof on the side adj...

A. F. Corey, B. E. Snyder

1975-01-01

209

Improved Outer Seal for First Stage Turbine.  

National Technical Information Service (NTIS)

The patent application relates to an outer air seal for the first stage turbine of an engine having the seal segments made of a high strength base material with a highly oxidation-corrosion resistant abradable alloy layer bonded to the surface. Another em...

A. F. Corey

1974-01-01

210

Characterization of Francisella tularensis Outer Membrane Proteins  

Microsoft Academic Search

Francisella tularensis is a gram-negative coccobacillus that is capable of causing severe, fatal disease in a number of mammalian species, including humans. Little is known about the proteins that are surface exposed on the outer membrane (OM) of F. tularensis, yet identification of such proteins is potentially fundamental to understanding the initial infection process, intracellular survival, virulence, immune evasion and,

Jason F. Huntley; Patrick G. Conley; Kayla E. Hagman; Michael V. Norgard

2007-01-01

211

UNITED NATIONS OFFICE FOR OUTER SPACE AFFAIRS  

E-print Network

NATIONS New York,2010 #12;ST/SPACE/50 #12;iii Preface This report was produced by the Office for Outer Navigation Satellite System 13 III. European Union The European Satellite Navigation System and the European-aided GEO-Augmented Navigation System 51 Annex Technical parameters 57 #12;#12;1 GPS/WAAS I. United

Schrijver, Karel

212

Accretion in the Early Outer Solar System  

Microsoft Academic Search

We describe calculations of the evolution of an ensemble of small planetesimals in the outer solar system. In a solar nebula with a mass of several times the minimum mass solar nebula, objects with radii of 100-1000 km can form on timescales of 10-100 Myr. Model luminosity functions derived from these calculations agree with current observations of bodies beyond the

Scott J. Kenyon; Jane X. Luu

1999-01-01

213

Transport across the bacterial outer membrane  

Microsoft Academic Search

Diffusion of small molecules across the outer membrane of gram-negative bacteria may occur through protein channels and through lipid bilayer domains. Among protein channels, many examples of trimeric porins, which produce water-filled diffusion channels, are known. Although the channels are nonspecific, the diffusion rates of solutes are often drastically affected by their gross physicochemical properties, such as size, charge, or

Hiroshi Nikaido

1993-01-01

214

Future exploration of the outer solar system  

NASA Astrophysics Data System (ADS)

Missions to the frigid outer reaches of our solar system present significant technological challenges, but there remains a breathtaking scope for new and exciting discoveries. Leigh Fletcher reports on an RAS meeting that demonstrated a host of innovative ideas to explore the giant planets.

Fletcher, Leigh

2013-04-01

215

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

216

The psychology of inner and outer space  

Microsoft Academic Search

In popular psychology, inner space refers to thoughts, imagery, dreams, attitudes, and feelings, while outer space refers to the external environment. Such dichotomy is artificial and pernicious, leading to the proposition that spiritual growth occurs by expansion of inner space through exercise, transcendental meditation, selfhypnosis, the judicious use of drugs, and so on. Pastors alerted to this insidious psychology know

Ruth M. Arstrong

1989-01-01

217

Extending synchrotron-based atomic physics experiments into the hard X-ray region  

SciTech Connect

The high-brightness, hard x-ray beams available from third-generation synchrotron sources are opening new opportunities to study the deepest inner shells of atoms, an area where little work has been done and phenomena not observed in less tightly bound inner-shells are manifested. In addition scattering processes which are weak at lower energies become important, providing another tool to investigate atomic structure as well as an opportunity to study photon/atom interactions beyond photoabsorption. In this contribution the authors discuss some of the issues related to extending synchrotron-based atomic physics experiments into the hard x-ray region from the physical and the experimental point of view. They close with a discussion of a technique, resonant Raman scattering, that may prove invaluable in determining the spectra of the very highly-excited states resulting from the excitation of deep inner shells.

LeBrun, T. [Argonne National Lab., IL (United States). Physics Div.

1996-12-31

218

Extending synchrotron-based atomic physics experiments into the hard x-ray region  

SciTech Connect

The high-brightness, hard x-ray beams available from third-generation synchrotron sources are opening new opportunities to study the deepest inner shells of atoms, an area where little work has been done and phenomena not observed in less tightly bound inner-shells are manifested. In addition scattering processes which are weak at lower energies become important, providing another tool to investigate atomic structure as well as an opportunity to study photon/atom interactions beyond photoabsorption. In this contribution we discuss some of the issues related to extending synchrotron-based atomic physics experiments into the hard x-ray region from the physical and the experimental point of view. We close with a discussion of a technique, resonant Raman scattering, that may prove invaluable in determining the spectra of the very highly-excited states resulting from the excitation of deep inner shells. {copyright} {ital 1997 American Institute of Physics.}

LeBrun, T. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States of America)

1997-01-01

219

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

220

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

221

Overview: Hard Rock Penetration  

SciTech Connect

The Hard Rock Penetration program is developing technology to reduce the costs of drilling and completing geothermal wells. Current projects include: lost circulation control, rock penetration mechanics, instrumentation, and industry/DOE cost shared projects of the Geothermal Drilling organization. Last year, a number of accomplishments were achieved in each of these areas. A new flow meter being developed to accurately measure drilling fluid outflow was tested extensively during Long Valley drilling. Results show that this meter is rugged, reliable, and can provide useful measurements of small differences in fluid inflow and outflow rates. By providing early indications of fluid gain or loss, improved control of blow-out and lost circulation problems during geothermal drilling can be expected. In the area of downhole tools for lost circulation control, the concept of a downhole injector for injecting a two-component, fast-setting cementitious mud was developed. DOE filed a patent application for this concept during FY 91. The design criteria for a high-temperature potassium, uranium, thorium logging tool featuring a downhole data storage computer were established, and a request for proposals was submitted to tool development companies. The fundamental theory of acoustic telemetry in drill strings was significantly advanced through field experimentation and analysis. A new understanding of energy loss mechanisms was developed.

Dunn, J.C.

1992-08-01

222

EVOLUTIONS IN HARDNESS SCALES DEFINITION  

Microsoft Academic Search

A conventional characteristic of hardness measurements is the strong dependency on the official definition of each scale. For this reason, and to assure a good connection between National Metrology Institutes (NMIs), scientific organizations (e.g., IMEKO1) and international organizations for standardization (e.g., ISO 2 and OIML 3 ), a new Working Group on Hardness (WGH) was created a few years ago

Giulio Barbato; Alessandro Germak; Konrad Herrmann; Samuel Low

223

Post-mortem erosion of fine-scale spatial structure of epibenthic megafauna on the outer Grand Bank of Newfoundland  

NASA Astrophysics Data System (ADS)

Marine organisms exhibit spatial variability at scales ranging from thousands of kilometres (biogeographic variability) to a few body lengths. Physical processes can increase spatial variability through selective sorting, or decrease it through mixing. We examine the effects of post-mortem processes on the spatial structure of empty shells and tests left by populations of molluscs and echinoderms on outer Grand Bank. Analysis of data from five photographic transects showed that spatial variability of shells and tests decreased relative to live organisms of the same species at scales greater than 140 m. Spatial variability did not increase relative to live specimens, with the exception of urchin tests at a scale of 20-30 m on two of five transects. We postulate that selective transport of shells does not occur in this environment at scales from 15 to 1500 m.

Schneider, D. C.; Haedrich, R. L.

1991-08-01

224

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

225

Hard rock drilling problems explained by hard rock pressure plots  

SciTech Connect

Hard rock drilling problems are frustrating. Hard rock pore pressure interpretation is baffling. Because of slow drilling in hard streaks and absence of kicks (in overpressured shale sections), it is generally assumed pore pressures are close to ''normal'' over long depth intervals. Many hard rock drilling problems could not be logically explained, if this were the case. Nothing could be further from the truth. Hard rocks are difficult to drill because of the extreme zig-zags from overpressured shales to sub-normally pressured sands and carbonates. It is impossible to drill anywhere near balanced in both situations, simultaneously. Hard rock drilling problems caused by underbalance or overbalance (or both) are a result. But, a better understanding of the presence and magnitude of these pressure shifts will help minimize the worst extremes of imbalance and more intelligently strike an optimum compromise, realizing that mud density and, especially, mud chemistry can never completely solve these hard rock drilling problems. Well log pressure plots in these erratic stratigraphies are so difficult to interpret that they often have been considered useless. The example pore pressure plots shown here, including the Pressure Evaluation Profile (PEP) log -- a side by side comparison of several different pressure sensitive responses -- help interpret and explain many of these problems in a simple, logical manner.

Gill, J.A.

1983-02-01

226

Compton Radiography of Imploded Capsule Shells  

NASA Astrophysics Data System (ADS)

In Inertial Confinement Fusion (ICF), a number of concurrent processes can contribute to degrading the degree and uniformity of compression of the imploding shell and fuel and hence the yield, namely hydro-instabilities, increase in entropy and residual asymmetries in the drive or target. Obtaining images at stagnation time of the compressed and relatively cold deuterium-tritium fuel surrounding the hot-spot is therefore fundamental to distinguishing between the degradation mechanisms so they may be mitigated on later shots. Here we report on the development and first demonstration of hard x-ray radiography of implosions obtained at photon energies around and above 100keV, where the Compton effect is the dominant contributor to the opacity. The radiographs of plastic shell implosions were obtained at the OMEGA/EP laser facility using gold micro wires in a point projection geometry and have a spatial resolution of ˜10?m and a temporal resolution of ˜10ps. This novel ``Compton'' radiography technique is an invaluable diagnostic tool for ICF targets and will be deployed at the National Ignition Facility (NIF).

Tommasini, Riccardo

2010-11-01

227

ALMA: Exploring theALMA: Exploring the Outer Limits ofOuter Limits of  

E-print Network

=B5) 2 polzns x DSB x 8 GHz (.6mm=B8, .45mm=B9, .35mm=B10) #12;Receivers/Front Ends Receiver noiseZ Machines ALMA: Exploring theALMA: Exploring the Outer Limits ofOuter Limits of RedshiftRedshift Al Wootten National Research Council Canada #12;5000m Chajnantor site ALMA APEX CBI Site Char #12

Groppi, Christopher

228

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

229

Irradiation chemistry in the outer solar system  

NASA Astrophysics Data System (ADS)

The dark, reddish tinged surfaces of icy bodies in the outer solar are usually attributed to the long term irradiation of simple hydrocarbons such as methane leading to the loss of hydrogen and the production of long carbon chains. While methane is stable and detected on the most massive bodies in the Kuiper belt, evidence of active irradiation chemistry is scant except for the presence of ethane on methane-rich Makemake and possible detections of ethane on more methane-poor Pluto and Quaoar. We have obtained deep high signal-to-noise spectra of Makemake from 1.5 to 2.5 microns in an attempt to trace the radiation chemistry in the outer solar system beyond the initial ethane formation. We present the first astrophysical detections of solid ethylene, acetylene, and possibly propane -- all expected products of the continued irradiation of methane, and use these species to map the chemical pathway from methane to long-chain hydrocarbons.

Brown, Michael E.

2014-11-01

230

High energy-resolution electron energy-loss spectroscopy study of the dielectric properties of multi-shell nanoparticles.  

PubMed

Nanoparticles, which have multi-shell structure, are expected to be stable and high efficient for the light-emitting devices. The efficiency of luminescence is considered to be affected by the multi-shell structure. In order to understand the mechanism of high efficiency luminescence, it is necessary to evaluate the multi-shell structure and dielectric properties from each particle. High energy-resolution electron energy-loss spectroscopy (HR-EELS) based on TEM is a powerful tool for this purpose. By comparing between the experimental and the simulated results, it is possible to evaluate the effect of the size and physical property of each shell material on the dielectric properties of multi-shell nanoparticles. In this study, simulations of EELS spectra of multi-shell nanoparticle (core: CdSe, inner shell: CdS, outer shell: ZnS) and mono-shell nanoparticle (core: CdSe, shell: CdS) were conducted by the dielectric continuum theory[1].Figure 1 shows calculated EELS spectra of multi and mono shell nanoparticles. The spectra are calculated from dielectric functions of single CdSe, CdS and ZnS crystals, which were experimentally derived from HR-EELS spectra by using Kramers-Kronig analysis. The radius of 6.9 nm for the nanoparticle in the simulation corresponds to the average size of actual synthesized nanoparticles. Energy positions of arrows in the inset correspond to band gap energies of CdSe, CdS and ZnS[2]. In the spectrum of multi-shell nanoparticle, the intensity corresponding to interband transition near band gap of CdSe is suppressed comparing with that of the mono shell nanoparticle. This result indicates that ZnS outer shell affects the intensity profile of EELS spectrum near band gap. This effect should be sensitive for the thickness of the shells. Thus, there is a possibility that the effect of size and thickness of each core and shell on dielectric properties of multi-shell nanoparticles could be evaluated by using HR-EELS technique.jmicro;63/suppl_1/i18/DFU039F1F1DFU039F1Fig. 1.Calculated EELS spectra. PMID:25359810

Nakahigashi, Naoyuki; Sato, Yohei; Terauchi, Masami; Uehara, Masato

2014-11-01

231

Fluxgate magnetometers for outer planets exploration  

Microsoft Academic Search

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 to2 times 10^{6}nT with optimum performance characteristics and low power

M. Acuna

1974-01-01

232

The Outer Electron Configuration in Metallic Copper  

Microsoft Academic Search

The effect on the atomic scattering factor of metallic copper of the 3d7.754s14p2.25 outer electron configuration, demanded by the Pauling valence of 5.50, is computed. Approximately a 6 percent lowering in intensity of the (111) reflection when compared with the atomic scattering factor computed on the basis of a Hartree-Fock calculation for the 3d104s1 configuration is predicted if the Pauling

A. I. Snow

1951-01-01

233

Environments in the Outer Solar System  

Microsoft Academic Search

The outer planets of our solar system Jupiter, Saturn, Uranus, and Neptune are fascinating objects on their own. Their intrinsic\\u000a magnetic fields form magnetic environments (so called magnetospheres) in which charged and neutral particles and dust are\\u000a produced, lost or being transported through the system. These magnetic environments of the gas giants can be envisaged as\\u000a huge plasma laboratories in

N. Krupp; K. K. Khurana; L. Iess; V. Lainey; T. A. Cassidy; M. Burger; C. Sotin; F. Neubauer

2010-01-01

234

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

235

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

236

A photometric survey of outer belt asteroids  

NASA Technical Reports Server (NTRS)

Since 1989, we have been conducting a research program devoted to the study of the Trojans and outer belt asteroids (Hilda and Cybele groups), in order to characterize their rotational properties and shapes. As an outcome of several observational campaigns, we determined rotational periods and lightcurve amplitudes for 23 distant asteroids, using both CCD and photoelectric photometry. In this paper, we compare the rotational properties of main belt asteroids and Trojans, based on the preliminary results of this survey.

Dimartino, M.; Gonano-Beurer, M.; Mottola, Stefano; Neukum, G.

1992-01-01

237

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

238

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

NASA Astrophysics Data System (ADS)

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.

Atabaev, Timur Sh; Kim, Hyung-Kook; Hwang, Yoon-Hwae

2013-08-01

239

Fabrication and catalytic performance of highly stable multifunctional core-shell zeolite composites.  

PubMed

Multifunctional Fe3O4@SiO2-Au@silicalite-1 core-shell magnetic zeolite composites were fabricated by combining a series of sol-gel process and vapor-phase transfer of silicalite-1 zeolite nanocrystal-seeded silica shells. The obtained composite has high magnetization (32.00 emu/g), stably confined and active gold nanoparticles (ca. 15 nm), and a hierarchical silicalite-1 outer shell. The core-shell composite exhibits a high efficiency of magnetic separability, excellent catalytic performance, and reusability for the reduction of 4-nitrophenol with conversion of 98% in 12 min. Moreover, it preserves a good stability after a high-temperature hydrothermal treatment. PMID:24041421

Wang, Xiaofang; Cui, Yuanzheng; Wang, Yang; Song, Xiaowei; Yu, Jihong

2013-10-01

240

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

241

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

242

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

243

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

244

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

245

Ejs Hard Disk Gas Model  

NSDL National Science Digital Library

The Ejs Hard Disk Gas model displays a two-dimensional gas made out of hard disks. Particles are initialized with a speed v=1 in a random direction and move with constant velocity until a collision occurs. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Hard Disk Gas model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_newton_HardDiskGas.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for statistical mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-06

246

Confined Hard Disk System Model  

NSDL National Science Digital Library

The Confined Hard Disk System is an idealized statistical mechanics model that simulates a two-dimensional system of hard disks confined to a box with a constant temperature thermal reservoir at one end and a movable piston at the other. Slow-moving particles are color-coded as blue and fast particles are color-coded as yellow. The model computes and plots the time evolution of the kinetic energy K per particle, the pressure P, and the volume V. The model also displays histograms and mean values of these quantities. The Confined Hard Disk System was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_hd_ConfinedHardDiskSystem.jar file will run the program if Java is installed.

Christian, Wolfgang

2010-12-27

247

STP Hard Disks Metropolis Program  

NSDL National Science Digital Library

The STP Hard Disks Metropolis program is a Monte Carlo simulation of hard disks in two dimensions. The default initial condition is a rectangular configuration of N=64 particles in a box of length L = 40. You can slowly increase the density of the gas (by setting the minimum scale length between centers to a value slightly less than 1) to explore phase transitions. STP HardDisksMetropolis is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double-clicking the stp_HardDisksMetropolis.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2009-03-06

248

Magna Charta of Outer Space for all nations  

NASA Astrophysics Data System (ADS)

This note presents the ten clauses of a Magna Charta of Outer Space for all nations which are supported by the UNISPACE '82 Resolutions, the I.T.U. Convention and the 1967 Outer Space Principles Treaty.

Finch, E. R.

249

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

NASA Astrophysics Data System (ADS)

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.; Eller, T. K.; Medricky, M.; Andres, M.

2013-12-01

250

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

251

Foam shell cryogenic ICF target  

DOEpatents

A uniform cryogenic layer of DT fuel is maintained in a fusion target having a low density, small pore size, low Z rigid foam shell saturated with liquid DT fuel. Capillary action prevents gravitational slumping of the fuel layer. The saturated shell may be cooled to produce a solid fuel layer.

Darling, Dale H. (Pleasanton, CA)

1987-01-01

252

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

253

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

254

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

255

Peaceful Use of Outer Space: principles of Japanese Policies on Utilization and Activities in Outer space  

NASA Astrophysics Data System (ADS)

" P e aceful use of outer space of outer space.....Principles of exploitation of outer space was passed in the Japanese Diet. It clearly mentioned that any activity of launching space object into outer space and developing launching rocket should be exclusively for peaceful purpose. NASDA was also established based upon the same principles of the public law. Japanese interpretation of Space Treaty and other related international agreements has been more strict on peaceful use of outer space, like non-military use rather than non-aggressive, because of influence of Japanese Constitution. Treaty and other agreements is analyzed through rapid development of its space activities, technologies and international cooperation with other space powers. Through more than thirty years experiences in space activities in public and private sectors, Japanese domestic laws and policies have not been changed in relation with basic principles. and laws relating to space activities in order to develop new space law and more international cooperation for space utilization rather than military use in new century.

Kosuge, Toshio

2002-01-01

256

Design and development of the optics system for the NHXM Hard X-ray and Polarimetric Mission  

Microsoft Academic Search

The New Hard X-ray Mission (NHXM) Italian project will be operated by 2016. It is based on 4 hard X-ray optics modules, each formed by 60 evenly spaced multilayer coated Wolter I mirror shells. For the achievement of a long focal length (10 m) an extensible bench is used. The pseudo-cylindrical Wolter I monolithic substrates where the multilayer coating is

Giovanni Pareschi; Gianpiero Tagliaferri; Primo Attinà; Stefano Basso; Giuseppe Borghi; Oberto Citterio; Marta Civitani; Vincenzo Cotroneo; Barbara Negri; Giorgia Sironi; Daniele Spiga; Dervis Vernani; Giuseppe Valsecchi

2009-01-01

257

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

258

Composite shell spacecraft seat  

NASA Technical Reports Server (NTRS)

A two-part seat (10) providing full body support that is specific for each crew member (30) on an individual basis. The two-part construction for the seat (10) can accommodate many sizes and shapes for crewmembers (30) because it is reconfigurable and therefore reusable for subsequent flights. The first component of the two-part seat construction is a composite shell (12) that surrounds the crewmember's entire body and is generically fitted to their general size in height and weight. The second component of the two-part seat (10) is a cushion (20) that conforms exactly to the specific crewmember's entire body and gives total body support in more complex environment.

Barackman, Victor J. (Inventor); Pulley, John K. (Inventor); Simon, Xavier D. (Inventor); McKee, Sandra D. (Inventor)

2008-01-01

259

Scientific Goals for Exploration of the Outer Solar System  

E-print Network

Scientific Goals for Exploration of the Outer Solar System How did the outer planets mold the solar system and create habitable worlds? OPAG Report DRAFT 14 August 2014 #12;2 Outline Executive Summary Over the science objectives for exploration of the outer solar system. It is consistent with Visions and Voyages

Rathbun, Julie A.

260

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

261

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

262

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

263

Development of polyvinyl alcohol shells overcoated with polystyrene layer for inertial confinement fusion experiments  

SciTech Connect

In inertial fusion experiments, the use of polymer shells provides more efficient ablative implosion and significantly reduced radiation preheat compared with the glass shells currently used. We have developed a method of fabricating polyvinyl alcohol (PVA) shells overcoated with a polystyrene (PS) layer. The method utilizes the emulsion technique previously developed by us, and employs three different liquid phases. A 5 wt. % aqueous PVA solution is mixed with a 7 wt. % PS solution in dichloromethane while stirring. The mixture is then poured into a 1 wt. % PS solution in cidhloromethane while stirring. The mixture is then poured into a 1 wt. % aqueous gelatin solution. The resulting emulsion is heated to evaporate the dichloromethane, resulting in solid PS shells encapsulating the PVA solution. The PS shells are subsequently washed and dried in vacuum to drive off the remaining water. As a result, a PVA shell is formed inside an overcoating PS shell which exhibits a good surface quality in the outer diameter and wall thickness regime currently desired by inertial confinement fusion experimenters.

Kubo, U.; Tsubakihara, H.

1987-07-01

264

Dust from the Outer Jovian Satellites  

NASA Astrophysics Data System (ADS)

It is argued that the outer region of the jovian system between ~ 50 and 300 jovian radii from Jupiter harbors a previously unknown dust population. We analyzed the data of the dust detector aboard the Galileo spacecraft collected from December 1995 to April 2001 during Galileo's numerous traverses of the outer jovian system. About 100 individual events are found to be compatible with impacts of grains moving around Jupiter in bound orbits. These micrometer-sized grains have moderate eccentricities and a wide range of inclinations -- from prograde to retrograde ones. The radial profile of the dust number density is nearly flat between about 50 and 300 jovian radii, and the absolute number density level ( ~ 10km-3) surpasses by a factor of ten that of the interplanetary background. We identify the sources of the bound grains with outer irregular satellites of Jupiter. Six tiny moons orbiting the planet in prograde and fourteen in retrograde orbits should produce dust through continuous bombardment by interplanetary micrometeoroids. Our analytic and numerical study of the ejecta dynamics shows that micrometer-sized particles from both satellite families, although strongly perturbed by solar tidal gravity and radiation pressure, would stay in bound orbits for hundreds of thousands of years. The ejecta cloud would embrace the orbits of the parent moons and have substantial asymmetries created by the radiation pressure and solar gravity perturbations. Spatial location of the impacts, grains' orbital inclinations, mass distribution, speeds, and number density of dust derived from the data are all consistent with the dynamical model. This work was funded by Deutsches Zentrum für Luft- und Raumfahrt (DLR).

Krivov, A. V.; Wardinski, I.; Spahn, F.; Krüger, H.; Grün, E.

2001-11-01

265

Indium Phosphide Core-Shell Nanowire Array Solar Cells with Lattice-Mismatched Window Layer  

NASA Astrophysics Data System (ADS)

We report surface-passivated core-shell InP nanowire array solar cells fabricated using catalyst-free selective-area metal organic vapor phase epitaxy. Reflectance measurements confirm enhanced light absorption due to significantly reduced reflectance over a wide spectral range. The wide-band-gap outer shell layer of core-multishell nanowires effectively passivates the large surface area of the nanowires, increasing the short-circuit current density and elevating the energy conversion efficiency by 6.35% under AM1.5G illumination. This passivation technique could open a new approach to nanowire-based photovoltaics with higher energy efficiency.

Yoshimura, Masatoshi; Nakai, Eiji; Tomioka, Katsuhiro; Fukui, Takashi

2013-05-01

266

Slow Extensional Flow Past a Non-Homogeneous Porous Spherical Shell  

NASA Astrophysics Data System (ADS)

An analytical investigation of extensional flow past a porous spherical shell of finite thickness with velocity slip at the surface is presented. The permeability of the shell varies continuously as a function of the radial distance. The flow in the porous region is assumed to obey Darcy's Law. The drag has been calculated in terms of normal volume flux rate per unit area of the outer and inner surfaces. Particular cases of flow past a homogeneous sphere and no-slip boundary condition have been deduced.

Rajvanshi, S. C.; Wasu, S.

2013-06-01

267

Eccentric features in Saturn's outer C ring  

NASA Technical Reports Server (NTRS)

The present search for possible eccentric and inclined features in the outer C ring of Saturn measured all sharp-edged feature radii in Voyager C ring data. The Maxwell ringlet and two other narrow ringlets, 1.470R(s) and 1.495R(s) are found to be eccentric; the latter is best fitted by a model describing a freely precessing Keplerian ellipse, while the former is not conclusively fitted by either a resonant forcing or a free precession model. These two eccentric ringlets are compared with the Titan and Maxwell ringlets.

Porco, Carolyn C.; Nicholson, Philip D.

1987-01-01

268

Accretion in the Early Outer Solar System  

E-print Network

We describe calculations of the evolution of an ensemble of small planetesimals in the outer solar system. In a solar nebula with a mass of several times the Minimum Mass Solar Nebula, objects with radii of 100-1000 km can form on timescales of 10-100 Myr. Model luminosity functions derived from these calculations agree with current observations of bodies beyond the orbit of Neptune (Kuiper Belt objects). New surveys with current and planned instruments can place better constraints on the mass and dynamics of the solar nebula by measuring the luminosity function at red magnitudes of 28 or larger.

Scott J. Kenyon; Jane X. Luu

1999-06-08

269

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

270

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

271

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

Code of Federal Regulations, 2012 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2012-07-01

272

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

Code of Federal Regulations, 2011 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2011-07-01

273

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

Code of Federal Regulations, 2011 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2011-07-01

274

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

Code of Federal Regulations, 2012 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2012-07-01

275

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

Code of Federal Regulations, 2013 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2013-07-01

276

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

Code of Federal Regulations, 2010 CFR

...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2010-07-01

277

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

Code of Federal Regulations, 2010 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2010-07-01

278

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

Code of Federal Regulations, 2013 CFR

...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced...Distinctively colored hard hats, or hard caps; identification for newly employed, inexperienced miners. Hard hats or hard caps distinctively different in color...

2013-07-01

279

Site-specific carbon deposition for hierarchically ordered core/shell-structured graphitic carbon with remarkable electrochemical performance.  

PubMed

A fascinating core-shell-structured graphitic carbon material composed of ordered microporous core and uniform mesoporous shell is fabricated for the first time through a site-specific chemical vapor deposition process by using a nanozeolite@mesostructured silica composite molecular sieve as the template. The mesostructure-directing agent cetyltrimethylammonium bromide in the shell of the template can be either burned off or carbonized so that it is successfully utilized as a pore switch to turn the shell of the template "on" or "off" to allow selective carbon deposition. The preferred carbon deposition process can be performed only in the inner microporous zeolite cores or just within the outer mesoporous shells, resulting in a zeolite-like ordered microporous carbon or a hollow mesoporous carbon. Full carbon deposition in the template leads to the new core-shell-structured microporous@mesoporous carbon with a nanographene-constructed framework for fast electron transport, a microporous nanocore with large surface area for high-capacity storage of lithium ions, a mesoporous shell with highly opened mesopores as a transport layer for lithium ions and electron channels to access inner cores. The ordered micropores are protected by the mesoporous shell, avoiding pore blockage as the formation of solid electrolyte interphase layers. Such a unique core-shell-structured microporous@mesoporous carbon material represents a newly established lithium ion storage model, demonstrating high reversible energy storage, excellent rate capability, and long cyclic stability. PMID:24039038

Lv, Yingying; Wu, Zhangxiong; Qian, Xufang; Fang, Yin; Feng, Dan; Xia, Yongyao; Tu, Bo; Zhao, Dongyuan

2013-10-01

280

Baroplastic core-shell nanoparticles  

NASA Astrophysics Data System (ADS)

A novel class of baroplastic core-shell nanoparticles was designed based on the pressure-induced miscibility between a low Tg component core and a high Tg component shell and obtained by a two-stage miniemulsion polymerization technique. By changing the amount of surfactant and monomer feed ratio, the size and composition of core-shell nanoparticles were controlled and almost homogenous particles with very narrow particle size distribution were obtained in each synthetic step. Trilayerd core-shell nanoparticles, which have an additional inner-core, were also successfully synthesized by sequential addition of monomers. The baroplasticity of these core-shell nanoparticles was demonstrated by compression molding and characterized by SANS, DSC, and TEM. Transparent objects were molded at temperatures as low as 25 oC under 5000 psi pressure, and recycled up to 10 times, from poly(n-butyl acrylate)/polystyrene or poly(2-ethyl hexyl acrylate)/polystyrene systems. The particle size was found to play an important role to determine the optical and mechanical properties of the resulting product. By comparison with bilayered core-shell nanoparticles, improved mechanical properties were observed in trilayered systems due to the enlarged interface region. Finally, blend or hybrid baroplastic core-shell nanoparticles were prepared incorporating other polymer or inorganic nanoparticles.

Woog Ryu, Sang; Gonzalez, Juan; Acar, Metin; Mayes, Anne

2004-03-01

281

Fabrication of Spherical Reflectors in Outer Space  

NASA Technical Reports Server (NTRS)

A process is proposed for fabrication of lightweight spherical reflectors in outer space for telescopes, radio antennas, and light collectors that would be operated there. The process would obviate the relatively massive substrates and frames needed to support such reflectors in normal Earth gravitation. According to the proposal, fabrication of a reflector would begin with blowing of a bubble to the specified reflector radius. Taking advantage of the outer-space vacuum as a suitable environment for evaporative deposition of metal, a metal-evaporation source would be turned on and moved around the bubble to deposit a reflective metal film over the specified reflector area to a thickness of several microns. Then the source would be moved and aimed to deposit more metal around the edge of the reflector area, increasing the thickness there to approximately equal to 100 micron to form a frame. Then the bubble would be deflated and peeled off the metal, leaving a thin-film spherical mirror having an integral frame. The mirror would then be mounted for use. The feasibility of this technology has been proved by fabricating a prototype at JPL. As shown in the figure, a 2-in. (.5-cm) diameter hemispherical prototype reflector was made from a polymer bubble coated with silver, forming a very smooth surface.

Wang, Yu; Dooley, Jennifer; Dragovan, Mark; Serivens, Wally

2005-01-01

282

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

283

Environments in the Outer Solar System  

NASA Astrophysics Data System (ADS)

The outer planets of our solar system Jupiter, Saturn, Uranus, and Neptune are fascinating objects on their own. Their intrinsic magnetic fields form magnetic environments (so called magnetospheres) in which charged and neutral particles and dust are produced, lost or being transported through the system. These magnetic environments of the gas giants can be envisaged as huge plasma laboratories in space in which electromagnetic waves, current systems, particle transport mechanisms, acceleration processes and other phenomena act and interact with the large number of moons in orbit around those massive planets. In general it is necessary to describe and study the global environments (magnetospheres) of the gas giants, its global configuration with its large-scale transport processes; and, in combination, to study the local environments of the moons as well, e.g. the interaction processes between the magnetospheric plasma and the exosphere/atmosphere/magnetosphere of the moon acting on time scales of seconds to days. These local exchange processes include also the gravity, shape, rotation, astrometric observations and orbital parameters of the icy moons in those huge systems. It is the purpose of this chapter of the book to describe the variety of the magnetic environments of the outer planets in a broad overview, globally and locally, and to show that those exchange processes can dramatically influence the surfaces and exospheres/atmospheres of the moons and they can also be used as a tool to study the overall physics of systems as a whole.

Krupp, N.; Khurana, K. K.; Iess, L.; Lainey, V.; Cassidy, T. A.; Burger, M.; Sotin, C.; Neubauer, F.

2010-06-01

284

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

285

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

2014-09-11

286

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

287

Recent progress in the ground calibration of the ASTRO-H Hard X-ray telescope (HXT-2)  

NASA Astrophysics Data System (ADS)

The 6th Japanese X-ray satellite, ASTRO-H, equips two Hard X-ray Telescopes (HXTs) to perform imaging spectroscopy up to 70 keV. The 2nd flight module (HXT-2) had been completed in July, 2013. After some environmental tests were passed, the X-ray performance of the HXT-2 was measured at the SPring-8 BL20B2, 3rd generation synchrotron facility. The angular resolution defined with a Half Power Diameter (HPD) was 1:'9 at 30 keV and 1:'8 at 50 keV. This small energy dependence is considered to be caused by the difference in image quality of each foil; the inner mirror shells have better quality than outer ones. The effective area was found to be 178 cm2 at 30 keV and 82 cm2 at 50 keV, both of which exceed the requirement. Furthermore, the detailed energy dependence of the effective area was examined for a limited aperture in the 30{70 keV band with a pitch of 1 keV. We also measured the off-axis dependence of the effective area at 50 keV, and then determined the optical axis. The field of view of the HXT-2 was found to be 5:'6 (FWHM of the vignetting function), consistent with the simulation. In this paper, we also report the detailed analysis of the ground calibration data, which will be used for image reconstruction by a ray-tracing simulator.

Mori, Hideyuki; Kuroda, Yuji; Miyazawa, Takuya; Awaki, Hisamitsu; Babazaki, Yasunori; Furuzawa, Akihiro; Hibino, Tatsuya; Iizuka, Ryo; Ishibashi, Kazunori; Iwase, Toshihiro; Kunieda, Hideyo; Kurihara, Daichi; Matsumoto, Hironori; Miyata, Yusuke; Saji, Shigetaka; Sugita, Satoshi; Suzuki, Yoshio; Tachibana, Sasagu; Tamura, Keisuke; Tawara, Yuzuru; Uesugi, Kentaro

2014-07-01

288

Development of a Prototype Nickel Optic for the Constellation-X Hard-X-Ray Telescope  

NASA Technical Reports Server (NTRS)

The Constellation-X mission, planned for launch in 2011, will feature an array of hard-x ray telescopes with a total collecting area goal of 1500 square centimeters at 40 keV. Various technologies are currently being investigated for the optics of these telescopes including multilayer-coated Eletroformed-Nickel-Replicated (ENR) shells. The attraction of the ENR process is that the resulting full-shell optics are inherently stable and offer the promise of good angular resolution and enhanced instrument sensitivity. The challenge for this process is to meet a relatively tight weight budget with a relatively dense material (rho nickel = 9 grams per cubic centimeters.) To demonstrate the viability of the ENR process we are fabricating a prototype HXT mirror module to be tested against a competing segmented-glass-shell optic. The ENR prototype will consist of 5 shells of diameters from 150 mm to 280 mm and of 426 mm total length. To meet the stringent weight budget for Con-X, the shells will be only 150 micron thick. The innermost of these will be coated with Iridium, while the remainder will be coated with graded-density multilayers. Mandrels for these shells are currently under fabrication (Jan 03), with the first shells scheduled for production in February 03. A tentative date of late Summer has been set for prototype testing. Issues currently being addressed are the control of stresses in the multiplayer coating and ways of mitigating their effects on the figure of the necessarily thin shells. Also, the fabrication, handling and mounting of these shells without inducing permanent figure distortions. A full status report on the prototype optic will be presented along with test results as available.

Basso, S.; Bruni, R. J.; Citerio, O.; Engelhaupt, D.; Ghigo, M.; Gorenstien, P.; Mazzoleni, F.; ODell, S. L.; Pareschi, G.; Ramsey, B. D.

2003-01-01

289

Outer core compositional layering and constraints on core liquid transport properties  

NASA Astrophysics Data System (ADS)

A variety of studies of the Earth's outer core report wave speeds near the top of the core slightly lower than reference models for core properties. One interpretation of the slower wavespeed profile is that it could represent a change in the core's light element concentration with depth in the core. I explore the consequences of this idea by interpreting the velocity profile as arising from diffusion gradients imposed in the outer core by various mechanisms. In order to estimate relative diffusion rates for light elements in liquid iron I also examine theories for transport properties of high pressure metallic liquids that are based on hard-sphere models. From the seismic wavespeed profile, an effective diffusivity may be obtained, which ranges from 0.1 to 10×10-7 m s depending on the particular boundary condition or initial condition chosen. The upper bound of the range is higher than expected from high pressure experiments and models of diffusivity in liquid metals for all elements except H. The lower bound is within the uncertainty of theoretical predictions and experimental determinations given the range of expected outer core temperatures if diffusion involves low Z elements. Plausible agreement arises from a class of models that represent diffusion out of a compositionally different layer existing from the time of the formation of the Earth. If the wavespeed profile in the core is diffusive in nature, the data suggest that it is an original feature of the core.

Helffrich, George

2014-04-01

290

Radio seismology of the outer solar corona  

NASA Astrophysics Data System (ADS)

Observed oscillations of coronal loops in extreme ultraviolet (EUV) lines have been successfully used to estimate plasma parameters in the inner corona (< 0.2R0, where R0 is the solar radius). However, coronal seismology in EUV lines fails for higher altitudes because of rapid decrease in line intensity. We aim to use radio observations to estimate the plasma parameters of the outer solar corona (> 0.2R0). We used the large Ukrainian radio telescope URAN-2 to observe type IV radio bursts at the frequency range of 8-32 MHz during the time interval of 09:50-12:30 UT on April 14, 2011. The burst was connected to C2.3 flare, which occurred in AR 11190 during 09:38-09:49 UT. The dynamic spectrum of radio emission shows clear quasi-periodic variations in the emission intensity at almost all frequencies. Wavelet analysis at four different frequencies (29 MHz, 25 MHz, 22 MHz, and 14 MHz) shows the quasi-periodic variation of emission intensity with periods of ~ 34 min and ~ 23 min. The periodic variations can be explained by the first and second harmonics of vertical kink oscillation of transequatorial coronal loops, which were excited by the same flare. The apex of transequatorial loops may reach up to 1.2 R0 altitude. We derive and solve the dispersion relation of trapped magnetohydrodynamic (MHD) oscillations in a longitudinally inhomogeneous magnetic slab. The analysis shows that a thin (with width to length ratio of 0.1), dense (with the ratio of internal and external densities of ? 20) magnetic slab with weak longitudinal inhomogeneity may trap the observed oscillations. Seismologically estimated Alfvén speed inside the loop at the height of ~ 1 R0 is ~ 1000 km s-1. The magnetic field strength at this height is estimated as ~ 0.9 G. Extrapolation of magnetic field strength to the inner corona gives ~ 10 G at the height of 0.1 R0. Radio observations can be successfully used for the sounding of the outer solar corona, where EUV observations of coronal loops fail. Therefore, radio seismology of the outer solar corona is complementary to EUV seismology of the inner corona. The research leading to these results has received funding from the Austrian 'Fonds zur Förderung der wissenschaftlichen Forschung' under project P24740-N27.

Zaqarashvili, Teimuraz; Melnik, Valentin; Brazhenko, Anatoliy; Panchenko, Mykhaylo; Konovalenko, Alexander; Dorovskyy, Vladimir; Rucker, Helmut

2014-05-01

291

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

292

HERO program: high-energy replicated optics for a hard-x-ray balloon payload  

NASA Astrophysics Data System (ADS)

We are developing high-energy replicated optics for a balloon-borne hard-x-ray telescope. When completed, the telescope will have around 130 cm2 of effective collecting area at 60 keV, and an angular resolution of hard-x-ray band. We present an overview of the HERO program, together with test data from the first mirror shell. The overall sensitivity of the full payload is given for planned long- and ultra-long-duration balloon flights.

Ramsey, Brian D.; Engelhaupt, Darell E.; Speegle, Chet O.; O'Dell, Stephen L.; Austin, Robert A.; Kolodziejczak, Jeffery J.; Weisskopf, Martin C.

1999-10-01

293

Shelling Percentage in Grain Sorghum.  

E-print Network

TEXAS AGRICULTURAL EXPERIMENT STATION AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS W. B. BIZZELL. President - LETIN NO. 294 MARCH,, 1922 L ,L . * DIVISION OF AGRONOMY SHELLING PERCENTAGE IN GRAIN SORGHUM B. YOUNGBLOOD, DIRECTOR COLLEGE...., Superintendent ' D. H. BENNETT, V. M. D., Veterinarian ?As of March 1. 1922. *In cooperation with School of Veterinary Medicine, A. and M. College of Texas. **In cooperation with United States Department of Agriculture. SHELLING PERCENTAGE IN GRAIN SORGHUM...

Conner, A. B. (Arthur Benjamin)

1922-01-01

294

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.

295

Optical cavity modes in gold shell colloids  

Microsoft Academic Search

Core-shell colloids composed of a dielectric core surrounded by a metal shell show geometric cavity resonances with optical properties that are distinctly different than those of the collective plasmon modes of the metal shell. We use finite-difference time domain calculations on silica colloids with a core diameter of 456 nm, surrounded by a 38 nm thick Au shell, to study

J. J. Penninkhof; L. A. Sweatlock; A. Moroz; H. A. Atwater; A. van Blaaderen; A. Polman

2008-01-01

296

The Digital Library Shell Yael Dubinsky  

E-print Network

The Digital Library Shell Yael Dubinsky University of Rome "La Sapienza" Department of Computer Libraries The Digital Library (DL) Shell The project of development the DL shell Demonstration Summary and future work #12;3 Agenda Digital Libraries The Digital Library (DL) Shell The project of development

Yehudai, Amiram

297

Properties of the quantized gravitating dust shell  

Microsoft Academic Search

We investigate the quantum dynamics of a self-gravitating spherical dust shell. The wave functions of the discrete spectrum are not localized inside the Schwarzschild radius. We argue that such shells can transform into white holes (in another space). It is plausible that shells with bare masses larger than the Planck mass loose their mass emitting lighter shells.

A. D. Dolgov; I. B. Khriplovich

1997-01-01

298

Instructive Properties of Quantized Gravitating Dust Shell  

Microsoft Academic Search

We investigate quantum dynamics of self-gravitating spherical dust shell. The wave functions of discrete spectrum are not localized inside the Schwarzschild radius. We argue that such shells can transform into white holes (in another space). It is plausible that shells with bare masses larger than the Planck mass loose their mass emitting lighter shells.

A. D. Dolgov; I. B. Khriplovich

299

Formation of the outer planets and satellites  

NASA Technical Reports Server (NTRS)

A mechanism for the formation of the outer planets is proposed, the basis of which is the idea that the giant planets contain an excess of chemically condensable materials over solar composition. Planetary cores were formed by the clumping together of chemically condensed bodies forming a thin disk in the solar nebula. Gas surrounding a core becomes unstable against collapse onto the core. In the case of Jupiter and Saturn, much of the collapsing gas goes into orbit about the formed planet, forming a relatively thin circumplanetary disks with differential rotation in the prograde sense. For Uranus and Neptune, the dynamical collapse mechanism is unlikely. A disk of gas around Uranus may have been formed during a collision of the protoplanet with a large body. The circumplanetary disks then form the basis for formation of satellite systems, in which the Goldreich-Ward instability mechanism plays a role.

Cameron, A. G. W.

1977-01-01

300

Organic Matter in the Outer Solar System  

NASA Technical Reports Server (NTRS)

Many solid bodies in the outer Solar System are covered with ices of various compositions, including water, carbon dioxide, methane, nitrogen, and other molecules that are solid at the low temperatures that prevail there. These ices have all been detected by remote sensing observations made with telescopes on Earth, or more recently, spacecraft in orbit (notably Galileo at Jupiter). The data also reveal other solid materials that could be minerals or complex carbon-bearing organic molecules. A study in progress using large ground-based telescopes to acquire infrared spectroscopic data, and laboratory results on the optical properties of complex organic matter, seeks to identify the non-icy materials on several satellites of Saturn, Uranus, and Neptune. The work on the satellites of Saturn is in part preparatory to the Cassini spacecraft investigation of the Saturn system, which will begin in 2004 and extend for four years.

Cruiskshank, Dale P.; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

301

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

302

Microbial biosynthesis of designer outer membrane vesicles.  

PubMed

Outer membrane vesicles (OMVs) are nanoscale proteoliposomes that are ubiquitously secreted by Gram-negative bacteria. Interest in these bioparticles has escalated over the years, leading to discoveries regarding their composition, production, and vaccine potential. Given that many steps in vesicle biogenesis are 'engineerable,' it is now possible to tailor OMVs for specific applications. Such tailoring involves modifying the OMV-producing bacterium through protein, pathway, or genome engineering in a manner that specifically alters the final OMV product. For example, targeted deletion or upregulation of genes associated with the cell envelope can modulate vesicle production or remodel the composition of vesicle components such as lipopolysaccharide. Likewise, bacteria can be reprogrammed to incorporate heterologously expressed proteins into either the membrane or lumenal compartment of OMVs. We anticipate that further research in the field of OMV engineering will enable continued design and biosynthesis of specialized vesicles for numerous biotechnological purposes ranging from the delivery of vaccines to the deconstruction of cellulosic substrates. PMID:24667098

Baker, Jenny L; Chen, Linxiao; Rosenthal, Joseph A; Putnam, David; DeLisa, Matthew P

2014-10-01

303

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

304

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

305

Nuclear Electric Propulsion for Outer Space Missions  

NASA Technical Reports Server (NTRS)

Today we know of 66 moons in our very own Solar System, and many of these have atmospheres and oceans. In addition, the Hubble (optical) Space Telescope has helped us to discover a total of 100 extra-solar planets, i.e., planets going around other suns, including several solar systems. The Chandra (X-ray) Space Telescope has helped us to discover 33 Black Holes. There are some extremely fascinating things out there in our Universe to explore. In order to travel greater distances into our Universe, and to reach planetary bodies in our Solar System in much less time, new and innovative space propulsion systems must be developed. To this end NASA has created the Prometheus Program. When one considers space missions to the outer edges of our Solar System and far beyond, our Sun cannot be relied on to produce the required spacecraft (s/c) power. Solar energy diminishes as the square of the distance from the Sun. At Mars it is only 43% of that at Earth. At Jupiter, it falls off to only 3.6% of Earth's. By the time we get out to Pluto, solar energy is only .066% what it is on Earth. Therefore, beyond the orbit of Mars, it is not practical to depend on solar power for a s/c. However, the farther out we go the more power we need to heat the s/c and to transmit data back to Earth over the long distances. On Earth, knowledge is power. In the outer Solar System, power is knowledge. It is important that the public be made aware of the tremendous space benefits offered by Nuclear Electric Propulsion (NEP) and the minimal risk it poses to our environment. This paper presents an overview of the reasons for NEP systems, along with their basic components including the reactor, power conversion units (both static and dynamic), electric thrusters, and the launch safety of the NEP system.

Barret, Chris

2003-01-01

306

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

307

Radial variations in modulus and hardness in SCS6 silicon carbide fibers  

Microsoft Academic Search

The mechanical properties of SCS-6 SiC fibers were measured as a function of fiber radius using nanoindentation techniques. Hardness and Young`s modulus were characterized for the material in all of the major regions of these fibers: the carbon core, the graphitic core coating, the inner SiC sheath, and the outer SiC sheath. The carbon core of the fibers was determined

A. B. Mann; T. P. Weihs; M. Balooch; J. H. Kinney

1999-01-01

308

Hypersonic vibrations of Ag@SiO2 (cubic core)-shell nanospheres.  

PubMed

The intriguing optical and catalytic properties of metal-silica core-shell nanoparticles, inherited from their plasmonic metallic cores together with the rich surface chemistry and increased stability offered by their silica shells, have enabled a wide variety of applications. In this work, we investigate the confined vibrational modes of a series of monodisperse Ag@SiO(2) (cubic core)-shell nanospheres synthesized using a modified Sto?ber sol-gel method. The particle-size dependence of their mode frequencies has been mapped by Brillouin light scattering, a powerful tool for probing hypersonic vibrations. Unlike the larger particles, the observed spheroidal-like mode frequencies of the smaller ones do not scale with inverse diameter. Interestingly, the onset of the deviation from this linearity occurs at a smaller particle size for higher-energy modes than for lower-energy ones. Finite element simulations show that the mode displacement profiles of the Ag@SiO(2) core-shells closely resemble those of a homogeneous SiO(2) sphere. Simulations have also been performed to ascertain the effects that the core shape and the relative hardness of the core and shell materials have on the vibrations of the core-shell as a whole. As the vibrational modes of a particle have a bearing on its thermal and mechanical properties, the findings would be of value in designing core-shell nanostructures with customized thermal and mechanical characteristics. PMID:21087022

Sun, Jing Ya; Wang, Zhi Kui; Lim, Hock Siah; Ng, Ser Choon; Kuok, Meng Hau; Tran, Toan Trong; Lu, Xianmao

2010-12-28

309

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

310

Age, growth rate and season of recruitment of Pinna nobilis (L) in the Croatian Adriatic determined from Mg:Ca and Sr:Ca shell profiles  

Microsoft Academic Search

Stable oxygen isotope analyses of U-shaped spines removed at intervals along profiles of the outer shell surface of Pinna nobilis (L) were used to reconstruct sea surface temperature (SST) and validate the periodicity of adductor muscle scar rings on the inner shell surface. Elemental ratios (Mg:Ca and Sr:Ca) of spines, determined using Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES), were compared

C. A. Richardson; M. Peharda; H. Kennedy; P. Kennedy; V. Onofri

2004-01-01

311

Sr\\/Ca and Mg\\/Ca ratios of ontogenetically old, long-lived bivalve shells ( Arctica islandica) and their function as paleotemperature proxies  

Microsoft Academic Search

The Sr\\/Ca and Mg\\/Ca ratios of many biogenic skeletons provide useful paleotemperature estimates. As yet however, it has remained largely impossible to obtain such information from bivalve shells. In the present study, metal-to-calcium values in the hinge plate (aragonite, outer shell layer) of four ontogenetically old (85 to 374year-old) specimens of the long-lived bivalve, Arctica islandica, were measured on a

Bernd R. Schöne; Zengjie Zhang; Pascal Radermacher; Julien Thébault; Dorrit E. Jacob; Elizabeth V. Nunn; Anne-France Maurer

2011-01-01

312

Hard Trying and These Recipes  

ERIC Educational Resources Information Center

Writers thrive when they are motivated to work hard, have regular opportunities to practice and reflect, and benefit from a knowledgeable teacher who knows writing. Student feedback to lessons during writing workshop helped guide Nancie Atwell in her quest to provide the richest and most efficient path to better writing.

Atwell, Nancie

2003-01-01

313

Indentation hardness testing of rock  

Microsoft Academic Search

The indentation testing was used for characterisation of hardness of rock materials. During the test, an indentor under applied load penetrated into the rock surface forming a crater. The testing procedure was developed to be in line with other ISRM Suggested Methods. The results show that standardised indentation testing allows for characterisation of mechanical properties of rock and that there

T Szwedzicki

1998-01-01

314

TESTING HARDNESS OF METAL ITEMS WITH MET-UD COMBINED PORTABLE HARDNESS TESTER  

Microsoft Academic Search

A new approach to portable hardness testers has been developed and introduced. It makes it possible to inspect hardness by one and the same hardness tester applying both, the ultrasonic contact impedance method and rebound method. Hardness tester wide possibilities which allow to inspect hardness of metal and alloy products with all standardized scales (Rockwell, Brinell, Vickers and Shore) have

Edward Aslanyan; Alexander Doynikov; Victor Pivovarov

315

Osmotic pressure acting on a semipermeable shell immersed in a solution of polyions.  

PubMed

We study theoretically the osmotic equilibria for a shell immersed in a suspension of polyions (e.g., colloids, polyelectrolytes, etc.). The shell is treated as impermeable for polyions, but allowing free diffusion of counterions that permeate inside the shell. From the solution of linearized Poisson-Boltzmann equation, we obtain the distribution of a potential and concentration profiles for polyions and counterions. We then obtain an explicit formula for the excess osmotic pressure of a polyion solution exerted on the shell, which includes a quadratic term in order to provide a self-consistency of a linear theory. As a result this pressure is larger than given by a concentration of polyions at the outer shell boundary obtained within linearized theory. It is, however, always smaller than or equal to the bulk osmotic pressure. This difference is attributed to a repulsive electrostatic disjoining pressure due to an overlap of counterion clouds inside the shell. A comparison with molecular dynamics simulations is provided and demonstrates that although the concentration profiles obtained within a linear theory deviate from simulation data at large potential, the theoretical and simulation pressures are in surprisingly good harmony. PMID:19123526

Tsekov, Roumen; Stukan, Mikhail R; Vinogradova, Olga I

2008-12-28

316

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

317

Synthesis of triple-layered Ag@Co@Ni core-shell nanoparticles for the catalytic dehydrogenation of ammonia borane.  

PubMed

Triple-layered Ag@Co@Ni core-shell nanoparticles (NPs) containing a silver core, a cobalt inner shell, and a nickel outer shell were formed by an in situ chemical reduction method. The thickness of the double shells varied with different cobalt and nickel contents. Ag0.04 @Co0.48 @Ni0.48 showed the most distinct core-shell structure. Compared with its bimetallic core-shell counterparts, this catalyst showed higher catalytic activity for the hydrolysis of NH3 BH3 (AB). The synergetic interaction between Co and Ni in Ag0.04 @Co0.48 @Ni0.48 NPs may play a critical role in the enhanced catalytic activity. Furthermore, cobalt-nickel double shells surrounding the silver core in the special triple-layered core-shell structure provided increasing amounts of active sites on the surface to facilitate the catalytic reaction. These promising catalysts may lead to applications for AB in the field of fuel cells. PMID:24302541

Qiu, Fangyuan; Liu, Guang; Li, Li; Wang, Ying; Xu, Changchang; An, Cuihua; Chen, Chengcheng; Xu, Yanan; Huang, Yanan; Wang, Yijing; Jiao, Lifang; Yuan, Huatang

2014-01-01

318

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

319

Stability of marginally outer trapped surfaces and existence of marginally outer trapped tubes  

E-print Network

The present work extends our short communication Phys. Rev. Lett. 95, 111102 (2005). For smooth marginally outer trapped surfaces (MOTS) in a smooth spacetime we define stability with respect to variations along arbitrary vectors v normal to the MOTS. After giving some introductory material about linear non self-adjoint elliptic operators, we introduce the stability operator L_v and we characterize stable MOTS in terms of sign conditions on the principal eigenvalue of L_v. The main result shows that given a strictly stable MOTS S contained in one leaf of a given reference foliation in a spacetime, there is an open marginally outer trapped tube (MOTT), adapted to the reference foliation, which contains S. We give conditions under which the MOTT can be completed. Finally, we show that under standard energy conditions on the spacetime, the MOTT must be either locally achronal, spacelike or null.

Lars Andersson; Marc Mars; Walter Simon

2007-04-22

320

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

321

HR Del remnant anatomy using 2-D sppectral data and 3-D photoionization shell models  

E-print Network

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, that forms two rings projected in the sky plane. These ring structures correspond to a closed hourglass shape, first proposed by Harman and O'Brien (2003). The equatorial emission enhancement is caused by the superimposed hourglass structures in the line of sight. The second structure seen only in the [OIII] and [NII] maps is located along the polar directions inside the hourglass structure. Abundances 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 2.5D photoionization modeling of the 3D shell was performed using the mass distribution inferred f...

Moraes, Manoel

2009-01-01

322

The outer boundary of the earth's electron radiation belt: Dependence upon L, energy, and equatorial pitch angle  

SciTech Connect

The authors present measurements of electrons made with high energy and pitch angle resolution, made at the equator, looking over a range of L shells in the neighborhood of the nightside trapping boundary. They define the trapping boundary to be the position where the trapped fluxes are equivalent to the background level. The transition region is studied in detail. Fine scale experimental measurements are of use in bringing together theoretical models which attempt to explain precipitating electrons from the outer boundary of the earth's electron radiation belt, with the broad range of measurements which are presently available. They took advantage of the measurement capabilities of the CRRES and SCATHA satellites for this work.

Imhof, W.L.; Robinson, R.M.; Nightingale, R.W.; Gaines, E.E.; Vondrak, R.R. (Lockheed Palo Alto Research Lab., CA (United States))

1993-04-01

323

Tectonics of the Outer Planet Satellites  

NASA Technical Reports Server (NTRS)

Tectonic features on the satellites of the outer planets range from the familiar, such as clearly recognizable graben on many satellites, to the bizarre, such as the ubiquitous double ridges on Europa, the twisting sets of ridges on Triton, or the isolated giant mountains rising from Io's surface. All of the large and middle-sized outer planet satellites except Io are dominated by water ice near their surfaces. Though ice is a brittle material at the cold temperatures found in the outer solar system, the amount of energy it takes to bring it close to its melting point is lower than for a rocky body. Therefore, some unique features of icy satellite tectonics may be influenced by a near-surface ductile layer beneath the brittle surface material, and several of the icy satellites may possess subsurface oceans. Sources of stress to drive tectonism are commonly dominated by the tides that deform these satellites as they orbit their primary giant planets. On several satellites, the observed tectonic features may be the result of changes in their tidal figures, or motions of their solid surfaces with respect to their tidal figures. Other driving mechanisms for tectonics include volume changes due to ice or water phase changes in the interior, thermoelastic stress, deformation of the surface above rising diapirs of warm ice, and motion of subsurface material toward large impact basins as they fill in and relax. Most satellites exhibit evidence for extensional deformation, and some exhibit strike-slip faulting, whereas contractional tectonism appears to be rare. Io s surface is unique, exhibiting huge isolated mountains that may be blocks of crust tilting and foundering into the rapidly emptying interior as the surface is constantly buried by deposits from hyperactive volcanoes. Of the satellites, diminutive Enceladus is spectacularly active; its south polar terrain is a site of young tectonism, copious heat flow, and tall plumes venting into space. Europa's surface is pervasively tectonized, covered with a diverse array of exotic and incompletely understood tectonic features. The paucity of impact craters on Europa suggests that its tectonic activity is ongoing. Geysers on Triton show that some degree of current activity, while tectonic features that cross sparsely cratered terrain indicate that it may also be tectonically active. Ganymede and Miranda both exhibit ancient terrains that have been pulled apart by normal faulting. On Ganymede these faults form a global network, while they are confined to regional provinces on Miranda. Ariel, Dione, Tethys, Rhea, and Titania all have systems of normal faults cutting across their surfaces, though the rifting is less pronounced than it is on Ganymede and Miranda. Iapetus exhibits a giant equatorial ridge that has defied simple explanation. The rest of the large and middle-sized satellites show very little evidence for tectonic features on their surfaces, though the exploration of Titan's surface has just begun.

McKinnon, W. B.; Collins, G. C.; Moore, J. M.; Nimmo, F.; Pappalardo, R. T.; Prockter, L. M.; Schenk, P. M.

2010-01-01

324

Shell layer variation in trace element concentration for the freshwater bivalve Elliptio complanata  

NASA Astrophysics Data System (ADS)

While the elemental chemistry of marine mollusk shells contains valuable environmental information, extending these interpretations to freshwater bivalve shells may be problematic, given the wide range of aqueous chemistries that exist in freshwater environments. To better understand the significance of these records, 20 bivalves were collected from four freshwater streams to determine the geochemical relationships that exist between the bivalve shell and their sources streams. The concentrations of manganese (Mn), copper (Cu), strontium (Sr), barium (Ba), and calcium (Ca) were analyzed by laser ablation inductively coupled plasma mass spectrometry across the inner (INL) and outer nacreous layer (ONL) of each shell for comparison to stream data collected over the period of shell growth. Within an individual shell, the content of Mn, Sr, and Ba were significantly higher in the INL than the ONL, while Cu concentrations were similar. Strontium and Ba concentrations co-varied between the two layers in 1:1 relationships, while Mn displayed a preferential enrichment in the INL that increased from 2:1 to 5:1 as the Mn content of the shell decreased. Each elemental profile can be correlated between shell layers, except for the trace element Cu, which appeared to be more closely related to the organic content of the shell. These results suggest that the major element geochemistry of the shell layers differentially reflect the aqueous chemistry of the water in which a bivalve lived, but that these records are most likely overprinted by physiological processes specific to the mantle tissue from which a particular shell layer is secreted. Distribution coefficients (shell M /Ca:water M /Ca, where M = trace element of interest) were calculated using the median molar elemental concentration for each shell (by layer), and the appropriate water concentration. Bivalves from a contaminated site were excluded from this analysis because their shells were anomalous in size and color. For the remaining 15 shells, distribution coefficients (INL and ONL) were: Mn (0.50 and 0.21), Sr (0.26 and 0.17), and Ba (0.05: INL only). Inner nacreous layer values were comparable to the upper end of published estimates for freshwater bivalves and fish otoliths, while the ONL values were comparable to the lower range of values. Inclusion of shells from the contaminated site resulted in the calculation of distribution coefficients that fell outside the range of published estimates. These results suggest that exposure to pollutants may have a bearing on the biological factors that control the elemental concentration of bivalve shells in freshwater environments. While researchers generally avoid sampling shell material from the INL because of the potential for shell dissolution, the similarity in elemental profile trends observed here suggests that both the INL and ONL record accurate geochemical information, but in distinct forms. An obvious advantage of INL analysis is the relative increase in elemental concentration, but this is afforded at the expense of spatial resolution. Considered collectively, these results suggest that valuable information can be gleaned from the elemental concentration of freshwater bivalve shells when care is taken in the choice of material from which these records are extracted.

Carroll, Monica; Romanek, Christopher S.

2008-10-01

325

The Magnetic Field in the Outer Heliosphere  

NASA Technical Reports Server (NTRS)

One of the great achievements of Parker was the prediction that the solar magnetic field would be drawn into Archimedian spirals as it is carried away from the Sun by the solar wind. This prediction has been amply confirmed by many in situ measurements in the intervening four decades. But, Parker made his prediction for a solar wind that expands into infinite space while we now know that the local interstellar medium (LISM) is far from empty and, in fact, confines the solar wind to a finite volume, known as the heliosphere, that extends to approximately 100 AU in the upstream direction (the solar system is moving through the LISM). Voyagers 1/2, presently at -80 AU, are approaching the upstream boundaries of the heliosphere and returning data on the properties of the magnetic field. This is important for understanding how galactic cosmic rays (GCRs) reach the Earth. Voyagers show that the IMF at 10-80 AU behaves much as Parker predicted - with two important exceptions. This is not surprising since the field is essentially passively advected by the solar wind out to 80 AU. But, new models say that nearer the heliosphere boundaries the field plays a major role in the solar wind-LISM interaction. However, of the many physical ingredients that constitute the outer heliosphere, the magnetic field poses some of the most interesting and difficult numerical modeling problems. Presently, only a few results have been published and much remains to be done. Here I will summarize the expected and measured behavior of the magnetic field at 80 AU. Then I will describe modeling predictions beyond 80 AU: magnetic "tornadoes", polarity envelopes, the Axford-Cranfill effect, inner and outer magnetic walls and more. I will also list what I believe to be important new modeling objectives. Finally, I will speculate on what is happening with the magnetic field near the nose of the heliosphere. My conclusion is that models of GCR modulation rarely incorporate even crudely realistic magnetic fields so it is a wonder that they are as successful as they are and no surprise that there are still important discrepancies between GCR modulation observations and the models.

Suess, S. T.

2004-01-01

326

Eggstreme Mechanics of Thin Shells  

NASA Astrophysics Data System (ADS)

I will present a series of experimental explorations on the rich mechanical behavior of thin elastic shells, subject to different forms of loading. First, I will discuss the geometry-induced rigidity of non-spherical pressurized shells under indentation, that can be used for non-destructive testing. I will proceed by characterizing the emergence and evolution of point and linear-like loci of localization on thin shells indented well into the nonlinear regime. I will then present a new mechanism that utilizes the compression of a thin-shell/soft-core system for switchable and tunable wrinkling on curved surfaces, that can be exploited for active aerodynamic drag control. Finally, I shall introduce the framework for buckling-induced folding (or ``Buckligami'') that involves functional structural transformations of patterned shells that can be excited to achieve encapsulation, flexure and twist. The main common feature underlying these series of examples is the prominence of geometry in dictating the complex mechanical behavior of slender soft structures, thereby making our results relevant and applicable over a wide range of length scales. Moreover, our findings suggest that we rethink our relationship with mechanical instabilities which, rather than modes of failure, can be embraced as opportunities for functionality that are scalable, reversible, and robust.

Reis, Pedro

2013-03-01

327

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

328

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

329

Neutral hydrogen in the outer Galaxy  

NASA Technical Reports Server (NTRS)

The H I 21 cm emission-line survey data of Stark et al. (1991) have been used to study the distribution of H I in the outer Galaxy and to improve understanding of the various systematic problems which influence all studies of Galactic H I. For n(H) greater than 0.01/cu cm, the distributions are similar to those found by Burton and te Lintel Hekkert (1986) but are 'better behaved' at substantially lower values of n(H). The z distribution of gas in the H I layer is best described as complicated. The behavior of the gaseous matter is consistent with the observed distribution of H I found in external spiral galaxies. In the directions of the maximum warp the average distance of the gas away from the Galactic plane reaches about 4 kpc at R about 24 kpc, while the flaring of the layer as measured by z(rms) increases to about 3 kpc. In directions where the warp layers particularly well measured, the Galaxy is followed to R about 30 kpc. The surface density of the atomic gas decreases exponentially.

Diplas, Athanassios; Savage, Blair D.

1991-01-01

330

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

331

Turbulent Mixing in the Outer Solar Nebula  

E-print Network

The effects of turbulence on the mixing of gases and dust in the outer Solar nebula are examined using 3-D MHD calculations in the shearing-box approximation with vertical stratification. The turbulence is driven by the magneto-rotational instability. The magnetic and hydrodynamic stresses in the turbulence correspond to an accretion time at the midplane about equal to the lifetimes of T Tauri disks, while accretion in the surface layers is thirty times faster. The mixing resulting from the turbulence is also fastest in the surface layers. The mixing rate is similar to the rate of radial exchange of orbital angular momentum, so that the Schmidt number is near unity. The vertical spreading of a trace species is well-matched by solutions of a damped wave equation when the flow is horizontally-averaged. The damped wave description can be used to inexpensively treat mixing in 1-D chemical models. However, even in calculations reaching a statistical steady state, the concentration at any given time varies substantially over horizontal planes, due to fluctuations in the rate and direction of the transport. In addition to mixing species that are formed under widely varying conditions, the turbulence intermittently forces the nebula away from local chemical equilibrium. The different transport rates in the surface layers and interior may affect estimates of the grain evolution and molecular abundances during the formation of the Solar system.

N. J. Turner; K. Willacy; G. Bryden; H. W. Yorke

2005-11-10

332

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.

333

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

334

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

335

Hard Photodisintegration of 3He  

NASA Astrophysics Data System (ADS)

Large angle photodisintegration of two nucleons from the 3He nucleus is studied within the framework of the hard rescattering model (HRM). In the HRM the incoming photon is absorbed by one nucleon's valence quark that then undergoes a hard rescattering reaction with a valence quark from the second nucleon producing two nucleons emerging at large transverse momentum . Parameter free cross sections for pp and pn break up channels are calculated through the input of experimental cross sections on pp and pn elastic scattering. The calculated cross section for pp breakup and its predicted energy dependency are in good agreement with recent experimental data. Predictions on spectator momentum distributions and helicity transfer are also presented.

Granados, Carlos

2011-02-01

336

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

337

Weld cladding of hard surfaces  

NASA Astrophysics Data System (ADS)

A literature study about clad welding of hard surfaces on steel is performed. The purpose was to see what kind of methods are mainly used, and particular attention is paid to clad welding of rolls. The main impression from this study is that several methods are in use. Some of these must be considered as 'too exotic' for the aim of the program, such as laser build-up welding. However, clad welding of hard surfaces to rolls is widely used around the world, and there is no need for particularly advanced welding methods to perform the work. The welding consumables and the way the welding is carried out is of more important character. The report will give some comments to this, and hopefully will give a short review of the current technology in this field.

Habrekke, T.

1993-02-01

338

Hard Disk PVT System Model  

NSDL National Science Digital Library

The Hard Disk PVT System simulates a two-dimensional system of particles confined between a thermal reservoir and a piston. This computer model is designed to study the equation of state for hard disks without other interactions. Slow-moving particles are color-coded as blue and fast particles are color-coded as yellow. Users can set the initial particle energy, the initial particle separation, and the thermal reservoir temperature Tr. The thermal conductivity parameter ? determines the probability that a collision with the thermal wall will affect (thermalize) the colliding particle. If the conductivity is one, the particle velocity after a reservoir collision is set according to Maxwell-Boltzmann statistics. If the conductivity is zero, all reservoir collisions are elastic and the internal energy E of the system is conserved.   Particles in this model have unit mass and interact through contact forces. Collision times are computed analytically because particles and pistons move with constant velocity between collisions. The time evolution algorithm advances the particle and piston positions from collision to collision until the requested time step ?t is achieved. The time evolution is then paused, data is accumulated, and the screen is redrawn. The Hard Disk PVT model is a supplemental simulation for the article "Pressure Oscillations in Adiabatic Compression" by Roland Stout in The Physics Teacher 49(5), 280-281 (2011) and has been approved by the author and The Physics Teacher editor. The model was developed using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_hd_HardDiskPVTSystem.jar file will run the program if Java is installed.

Christian, Wolfgang

2011-03-12

339

A Dynamic Hard Sphere Model  

Microsoft Academic Search

A simple two-dimensional model, in which uniform hard spheres are made to move steadily and apparently nearly at random, is described. At low sphere density the model exhibits ``gas-like'' behavior. As the density is increased the behavior becomes more ``liquid-like'' and then ``crystallization'' occurs. Many dynamic atomic phenomena, believed to occur in the gas, liquid, or solid state, are illustrated

D. Turnbull; R. L. Cormia

1960-01-01

340

Recommended Exploration Strategy for the Outer Planets 2013-2022: Goals and Priorities  

NASA Astrophysics Data System (ADS)

Important scientific discoveries continue to be made in the outer solar system through NASA missions and research programs (for example, via the ongoing Cassini mission at Saturn, the New Horizons encounter with Jupiter in 2007, and earth-based studies of Uranus and Neptune). The Outer Planets Assessment Group (OPAG) was established by NASA to identify scientific priorities and pathways for outer solar system exploration, because the outer solar system provides critical clues to unraveling the mysteries of how solar systems form and evolve, how planetary systems become habitable, and how life has evolved in our solar system. Addressing such scientific questions requires a balanced strategy of outer solar system exploration that includes steady support for vigorous programs of basic research, data analysis, and technology development. Fundamental new discoveries are best made with a mixture of mission sizes that includes large (flagship) missions, along with medium-sized and smaller-sized (as practical) missions. Such a strategy is most efficiently implemented as a coherent Outer Planets Exploration Program. Missions to the outer solar system are major undertakings, requiring large and expensive launch vehicles, long mission durations, highly reliable (frequently radiation hard) and autonomous spacecraft, and radioisotope power sources in most cases. OPAG recommends that the Decadal Survey explore the possibilities for a program structure/categorization that could allow ‘small flagship’ class missions to be considered, providing a greater range of choice and capabilities in the mix to balance program size and science return. With the Galileo mission concluded, the Cassini equinox mission in progress, and Juno in development, OPAG strongly endorses the competitive selection by NASA of the Jupiter Europa Orbiter (JEO) as the next Outer Planets Flagship and as part of the Europa Jupiter System Mission (EJSM) with ESA, a collaboration that includes a Ganymede orbiter and an increased focus on Jupiter science; OPAG strongly recommends support of JEO and EJSM in the Decadal Survey. In addition, OPAG strongly endorses approval by NASA of the Cassini Solstice Mission, including the Juno-like end-of-mission scenario, given the likely phenomenal return on investment. OPAG also advocates the need for a focused technology program for the next Outer Planet Flagship Mission after EJSM, in order to be ready for a launch in the mid-2020s. In this regard, a return to Titan and Enceladus is the highest priority. Technologies that require long-term investment for missions beyond the next decade should also be considered. New Frontiers class missions that should be considered in the interim include (but not in priority order) probe missions to the giant planets, an Io observer, a Neptune/Triton/KBO rendezvous, and a Titan in-situ explorer or probe, and OPAG recommends that these be studied, costed, and added the approved New Frontiers mission set.

McKinnon, W. B.; Johnson, T. V.

2009-12-01

341

Radio emission from nova shells  

NASA Technical Reports Server (NTRS)

This paper presents data from multifrequency radio observations of the novae HR Del 1967 and FH Ser 1970 made from June 1970 to December 1978 and of V1500 Cyg 1975 made from September 1975 to December 1978. The data for FH Ser and V1500 Cyg constitute a complete history of the important phases of their radio 'light' curves, while all but the rising portion of the optically thick phase of an expanding nova shell is present for HR Del. A simple solution of the spherically symmetric equations of mass and momentum conservation for an isothermal gas, for which pressure gradients are effectively decoupled from the dynamics, is shown to fit the radio data for all three novae quite well. The main features of this model are strong density and velocity gradients that lead to long periods when the 'observable' shell evolves from an optically thick 'disk' to a completely optically thin shell.

Hjellming, R. M.; Wade, C. M.; Vandenberg, N. R.; Newell, R. T.

1979-01-01

342

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

343

Lovelock thin-shell wormholes  

NASA Astrophysics Data System (ADS)

We construct the asymptotically flat charged thin-shell wormholes of Lovelock gravity in seven dimensions by a cut-and-paste technique and apply the generalized junction conditions in order to calculate the energy-momentum tensor of these wormholes on the shell. We find that for negative second-order and positive third-order Lovelock coefficients, there are thin-shell wormholes that respect the weak energy condition. In this case, the amount of normal matter decreases as the third-order Lovelock coefficient increases. For positive second- and third-order Lovelock coefficients, the weak energy condition is violated and the amount of exotic matter decreases as the charge increases. Finally, we perform a linear stability analysis against a symmetry-preserving perturbation and find that the wormholes are stable, provided the derivative of surface pressure density with respect to surface energy density is negative and the throat radius is chosen suitably.

Dehghani, M. H.; Mehdizadeh, M. R.

2012-01-01

344

Low Temperature Processing of Core-Shell Baroplastics  

NASA Astrophysics Data System (ADS)

Baroplastics are nanophase materials that exhibit the ability to flow and be molded under pressure at reduced temperatures. Core-shell nanoparticle baroplastics comprised of one soft component, such as poly(butyl acrylate), and one glassy component, such as polystyrene, were synthesized by miniemulsion polymerization and processed at temperature as low as 25^oC by compression molding and extrusion. The resulting specimens are clear and well-defined solid objects with a diverse range of mechanical properties depending on composition, ranging from tough, rigid materials to rubbery materials comparable to commercial thermoplastic elastomers. SANS and DSC measurements on the core-shell materials before and after processing reveal pressure induced partial mixing of the hard and soft components, while TEM studies show that the core-shell morphology is substantially retained, even after 20 reprocessing cycles. Mechanical properties of the processed samples were measured to elucidate the effects of processing pressure and temperature and to isolate the role of the pressure-induced miscibility.

Gonzalez Leon, Juan A.

2005-03-01

345

Shelling in low dimensional manifolds  

E-print Network

-manifolds. These results will include some extensions of a theorem by Treybig which states that every compact 3-manifold has a triangulation in which every 3-cell, which is the union of 3-simplexes of the tri- angulation, can be shelled, Also, a... triangulation of E will be con- 3 structed which has the property that certain 3-cells, which are the union of 3-simplexes of the triangulation, can be shelled. iv ACKNOWLEDGMENTS I would like to express my gratitude to the chairman of my committee, Dr. L...

Murray, William Owen

2012-06-07

346

Impact of aging on radiation hardness  

SciTech Connect

Burn-in effects are used to demonstrate the potential impact of thermally activated aging effects on functional and parametric radiation hardness. These results have implications on hardness assurance testing. Techniques for characterizing aging effects are proposed.

Shaneyfelt, M.R.; Winokur, P.S.; Fleetwood, D.M. [and others

1997-07-01

347

Why Are Drugs So Hard to Quit?  

MedlinePLUS Videos and Cool Tools

Video: Why Are Drugs So Hard to Quit? Your browser does not support inline frames or is currently configured not to display inline ... link under the video: In English: Why Are Drugs So Hard to Quit? En español: ¿Por Qué ...

348

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

349

Off-shell nilpotency for on-shell reducibility  

SciTech Connect

In this paper the direct way of Lagrangian BRS gauge-fixing the authors proposed recently is applied to reducible gauge theories: antisymmetric tensor gauge theories are considered as definite examples. It enables us to do without ad hoc ghosts for ghosts. It also achieves BRS-exact forms of full gauge-fixing terms by means of off-shell nilpotent BRS transformations.

Izawa, K.I. (Kyoto Univ. (Japan). Dept. of Physics)

1992-10-20

350

Project EARTH-12-SHELL6: Shell Geoscience Laboratory (2)  

E-print Network

that some natural fractures can form at very shallow burial depths during early diagenesis (Shin et al. 2008 during early burial Supervisors: Joe Cartwright, Stephen Hesselbo and Bruce Levell (Shell (subject to contract) The development of natural fracture systems in fine-grained sediments is becoming

Henderson, Gideon

351

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

352

Long-Lived Glass Mirrors For Outer Space  

NASA Technical Reports Server (NTRS)

Paper summarizes available knowledge about glass mirrors for use in outer space. Strengths and weaknesses of various types of first and second reflective surfaces identified. Second-surface glass mirrors used in outer space designed to different criteria more stringent for terrestrial mirrors. Protons, electrons, cosmic rays, meteorites, and orbiting space debris affect longevities of components. Contamination also factor in space.

Bouquet, Frank L.; Maag, Carl R.; Heggen, Philip M.

1988-01-01

353

Teaching several themes relating to inner and outer planets  

Microsoft Academic Search

Making astronomy more accessible and attractive to students is very important. In keeping with this objective, we present an activity on teaching planetary motion and the relative positions of the Sun, Earth and an inner or outer planet. We give special consideration to the phases of an inner planet and the gibbous appearance of an outer planet to motivate the

Rosa M. Ros

1999-01-01

354

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

355

Determination of hardness and hardness penetration depth of metal components by Non Linear Harmonics Analysis  

NASA Astrophysics Data System (ADS)

For the characterization of steel quality, hardness is a very important parameter. The magneto-inductive Non Linear Harmonics Analysis (NLHA) has been developed and used as a non destructive technique for measuring core hardness, surface hardness and hardness penetration depth of steel components. A description of the working principle of NLHA is given together with the setup of a typical hardness measuring system. Examples are given for the determination of carbon content in steel foils, measurement of core hardness in gear bolts where the hardness was controlled by tempering. Further results demonstrate measurements of core hardness, surface hardness and hardness penetration depth of nitration hardened steel samples. The final example shows a hardness profile of a case hardened shaft.

Stegemann, D.; Reimche, W.; Feiste, K. L.; Reichert, Ch.; Marques-Fetter, P.

1999-12-01

356

Far Outer Galaxy H II Regions  

NASA Technical Reports Server (NTRS)

We have made a multifrequency (6, 3.6, and 2 cm), high-resolution (3"-6"), radio continuum survey of IRAS selected sources from the catalogue of Wouterloot & Brand (1989) to search for and study H II regions in the far outer Galaxy. We identified 31 sources in this catalog with well determined galactocentric distances, and with R approx.. greater than 15 kpc and L(sub FIR) approx.greater than 10(exp 4) solar luminosity, indicating the presence of high-mass star-formation. We have observed 11 of these sources with the Very Large Array (VLA). We observed the sources at 6 and 2 cm using "scaled arrays", making possible a direct and reliable comparison of the data at these two wavelengths for the determination of spectral indices. We detected a total of 12 radio sources, of which 10 have spectral indices consistent with optically-thin free-free emission from H II regions. Combined with previous VLA observations by other investigators, we have data on a total of 15 H II regions at galactocentric distances of 15 to 18.2kpc, among the most remote H II regions found in our Galaxy. The sizes of the H II regions range from approx. less than 0.10 to 2.3 pc. Using the measured fluxes and sizes, we determine the electron densities, emission measures, and excitation parameters of the H II regions, as well as the fluxes of Lyman continuum photons needed to keep the nebulae ionized. The sizes and electron densities are consistent with most of the sources detected in this survey being compact or ultracompact H II regions. Seven of the fifteen H II regions have sizes approx. less than 0.20 pc. Assuming simple pressure-driven expansion of the H II regions, these sizes indicate ages approx. less than 5 x 10(exp 4) yr, or only 1% of the lifetime of an O star, which implies an unlikely overabundance of O stars in the outer Galaxy. Thus, the large number of compact H II regions suggests that the time these regions spend in a compact phase must be much longer than their dynamical expansion times. Five of the fifteen H II regions have cometary shapes; the remainder are spherical or unresolved. Comparison of the radio continuum data with molecular line maps suggests that the cometary shape of the two H II regions in S 127 may be due to pressure confinement of the expanding ionized gas, as in the "blister" or "champagne flow" models of H II regions. Comparison of the radio continuum data with the IRAS far-infrared data indicates that the five most luminous H II regions are consistent with a single 0 or B star exciting a dust-free H II region. Subject headings: stars: formation - ISM: H II regions - ISM: individual objects: S 127 radio continuum: interstellar

Rudolph, A. L.; deGues, E. J.; Brand, J.; Wouterloot, J. G. A.; Gross, Anthony R. (Technical Monitor)

1994-01-01

357

Prevalence of anisotropic shell growth in rare earth core-shell upconversion nanocrystals.  

PubMed

Through a series of carefully executed experiments, we discovered the prevalence of anisotropic shell growth in many upconversion NaREF4 systems caused by a combination of factors: selective adsorption of ligands on the core surface due to the core crystal structure, ligand etching, and the lattice mismatch between core and shell components. This could lead to incomplete shell formation in core-shell nanocrystals under certain conditions. Shell growth is always faster in the a and b crystallographic directions than in the c direction. In the case of a larger lattice mismatch between the core and shell, shell growth only occurs in the a and b directions resulting in an oblong core-shell structure. These findings are useful for rationalizing shell-dependent emission properties, understanding the emission mechanisms in complex core-shell nanostructures, and for creating accurate models of core-shell designs for multifunctionality and optimal performance in applications. PMID:23570424

Zhang, Chao; Lee, Jim Yang

2013-05-28

358

Transitions between turbulent and laminar superfluid vorticity states in the outer core of a neutron star  

E-print Network

We investigate the global transition from a turbulent state of superfluid vorticity to a laminar state, and vice versa, in the outer core of a neutron star. By solving numerically the hydrodynamic Hall-Vinen-Bekarevich-Khalatnikov equations for a rotating superfluid in a differentially rotating spherical shell, we find that the meridional counterflow driven by Ekman pumping exceeds the Donnelly-Glaberson threshold throughout most of the outer core, exciting unstable Kelvin waves which disrupt the rectilinear vortex array, creating a vortex tangle. In the turbulent state, the torque exerted on the crust oscillates, and the crust-core coupling is weaker than in the laminar state. This leads to a new scenario for the rotational glitches observed in radio pulsars: a vortex tangle is sustained in the differentially rotating outer core by the meridional counterflow, a sudden spin-up event brings the crust and core into corotation, the vortex tangle relaxes back to a rectilinear vortex array, then the crust spins down electromagnetically until enough meridional counterflow builds up to reform a vortex tangle. The turbulent-laminar transition can occur uniformly or in patches; the associated time-scales are estimated from vortex filament theory. We calculate numerically the global structure of the flow with and without an inviscid superfluid component, for Hall-Vinen and Gorter-Mellink forms of the mutual friction. We also calculate the post-glitch evolution of the angular velocity of the crust and its time derivative, and compare the results with radio pulse timing data, predicting a correlation between glitch activity and Reynolds number.

C. Peralta; A. Melatos; M. Giacobello; A. Ooi

2006-07-08

359

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

360

Fault tolerant, radiation hard, high performance digital signal processor  

NASA Technical Reports Server (NTRS)

An architecture has been developed for a high-performance VLSI digital signal processor that is highly reliable, fault-tolerant, and radiation-hard. The signal processor, part of a spacecraft receiver designed to support uplink radio science experiments at the outer planets, organizes the connections between redundant arithmetic resources, register files, and memory through a shuffle exchange communication network. The configuration of the network and the state of the processor resources are all under microprogram control, which both maps the resources according to algorithmic needs and reconfigures the processing should a failure occur. In addition, the microprogram is reloadable through the uplink to accommodate changes in the science objectives throughout the course of the mission. The processor will be implemented with silicon compiler tools, and its design will be verified through silicon compilation simulation at all levels from the resources to full functionality. By blending reconfiguration with redundancy the processor implementation is fault-tolerant and reliable, and possesses the long expected lifetime needed for a spacecraft mission to the outer planets.

Holmann, Edgar; Linscott, Ivan R.; Maurer, Michael J.; Tyler, G. L.; Libby, Vibeke

1990-01-01

361

DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION  

E-print Network

DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION ATISH DAS SARMA, STEPHAN HOLZER on the hardness of distributed approximation for many classical optimization problems including minimum spanning the previous hardness of approximation bound of Elkin [STOC 2004] as well as the lower bound for (exact) MST

362

Distributed Verification and Hardness of Distributed Approximation  

E-print Network

Distributed Verification and Hardness of Distributed Approximation Atish Das Sarma Google Foundation (BSF). Permission to make digital or hard copies of all or part of this work for personal on the hardness of distributed approxi- mation for many classical optimization problems including minimum spanning

363

Collisions of Nuclei: New Ideas for Hard  

E-print Network

Collisions of Nuclei: New Ideas for Hard Probes Rainer Fries Texas A&M University & RIKEN BNL collisions and hard probes Hadron chemistry and flavor conversions Tomography + development of a new test Equilibration, thermalization Quark Gluon Plasma Non-perturbative dynamics Hard particles (PT > 1 -2GeV): Rare

364

Instrumented hardness testing using a flat punch  

Microsoft Academic Search

Instrumented hardness tests using a flat punch were performed and analysed using an original approach. The quality of the hardness-flow stress correlation using this particular type of indenter is investigated. It is found that some characteristic force values of the instrumented hardness test are very well correlated to yield and tensile strength.

M. Scibetta; E. Lucon; R. Chaouadi; E. van Walle

2003-01-01

365

Artificially soft and hard surfaces in electromagnetics  

Microsoft Academic Search

A transversely corrugated surface as used in corrugated horn antennas represents a soft boundary. A hard boundary is made by using longitudinal corrugations filled with dielectric material. The concept of soft and hard surfaces is treated in detail, considering different geometries. It is shown that both the hard and soft boundaries have the advantage of a polarization-independent reflection coefficient for

Per-Simon Kildal

1990-01-01

366

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

367

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

368

Shell Centre for Mathematical Education  

NSDL National Science Digital Library

The Shell Centre for Mathematical Education, a centre for research and development within the School of Education at the University of Nottingham, offers WWW pages which includes a collection of information technologies used in the classroom, details of publications and research, as well as a Distractions Page "intended to contain entertaining items of varying degrees of educational value."

369

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

370

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

371

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

372

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

373

Alternative mechanisms of increased eggshell hardness of avian brood parasites relative to host species  

PubMed Central

Obligate brood parasitic birds lay their eggs in nests of other species and parasite eggs typically have evolved greater structural strength relative to host eggs. Increased mechanical strength of the parasite eggshell is an adaptation that can interfere with puncture ejection behaviours of discriminating hosts. We investigated whether hardness of eggshells is related to differences between physical and chemical traits from three different races of the parasitic common cuckoo Cuculus canorus, and their respective hosts. Using tools developed for materials science, we discovered a novel correlate of increased strength of parasite eggs: the common cuckoo's egg exhibits a greater microhardness, especially in the inner region of the shell matrix, relative to its host and sympatric non-host species. We then tested predictions of four potential mechanisms of shell strength: (i) increased relative thickness overall, (ii) greater proportion of the structurally harder shell layers, (iii) higher concentration of inorganic components in the shell matrix, and (iv) elevated deposition of a high density compound, MgCO3, in the shell matrix. We confirmed support only for hypothesis (i). Eggshell characteristics did not differ between parasite eggs sampled from different host nests in distant geographical sites, suggesting an evolutionarily shared microstructural mechanism of stronger parasite eggshells across diverse host-races of brood parasitic cuckoos. PMID:21561966

Igic, Branislav; Braganza, Kim; Hyland, Margaret M.; Silyn-Roberts, Heather; Cassey, Phillip; Grim, Tomas; Rutila, Jarkko; Moskat, Csaba; Hauber, Mark E.

2011-01-01

374

Alternative mechanisms of increased eggshell hardness of avian brood parasites relative to host species.  

PubMed

Obligate brood parasitic birds lay their eggs in nests of other species and parasite eggs typically have evolved greater structural strength relative to host eggs. Increased mechanical strength of the parasite eggshell is an adaptation that can interfere with puncture ejection behaviours of discriminating hosts. We investigated whether hardness of eggshells is related to differences between physical and chemical traits from three different races of the parasitic common cuckoo Cuculus canorus, and their respective hosts. Using tools developed for materials science, we discovered a novel correlate of increased strength of parasite eggs: the common cuckoo's egg exhibits a greater microhardness, especially in the inner region of the shell matrix, relative to its host and sympatric non-host species. We then tested predictions of four potential mechanisms of shell strength: (i) increased relative thickness overall, (ii) greater proportion of the structurally harder shell layers, (iii) higher concentration of inorganic components in the shell matrix, and (iv) elevated deposition of a high density compound, MgCO(3), in the shell matrix. We confirmed support only for hypothesis (i). Eggshell characteristics did not differ between parasite eggs sampled from different host nests in distant geographical sites, suggesting an evolutionarily shared microstructural mechanism of stronger parasite eggshells across diverse host-races of brood parasitic cuckoos. PMID:21561966

Igic, Branislav; Braganza, Kim; Hyland, Margaret M; Silyn-Roberts, Heather; Cassey, Phillip; Grim, Tomas; Rutila, Jarkko; Moskát, Csaba; Hauber, Mark E

2011-11-01

375

Bi-functional RuO2-Co3O4 core-shell nanofibers as a multi-component one-dimensional water oxidation catalyst.  

PubMed

The core-shell structure of RuO2-Co3O4 fibers comprising the inner region of highly conductive RuO2 and the outer region of catalytic Co3O4 provided a fast and effective transport pathway for holes to O2-evolving sites, leading to a highly efficient water oxidation performance. PMID:23928721

Ko, Jong Wan; Ryu, Won-Hee; Kim, Il-Doo; Park, Chan Beum

2013-10-28

376

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

377

Hard body amphiphiles at a hard wall JOSEPH M. BRADER1y  

E-print Network

Hard body amphiphiles at a hard wall JOSEPH M. BRADER1y , CHRISTIAN VON FERBER2 and MATTHIAS 2003) We investigate the structure of amphiphilic molecules exposed to a substrate that is modelled by a hard wall. Our simple model amphiphiles consist of a hard sphere head group to which a vanishingly thin

Ott, Albrecht

378

Hardness Standardization Our objective is to standardize and improve hardness measurement  

E-print Network

Hardness Standardization METALS Our objective is to standardize and improve hardness measurement both in the U.S. and internationally. NIST is the U.S. National Metrology Institute (NMI) for hardness, and as such, is responsible for traceability in hardness measurements. Objective Impact and Customers

379

Hard Questions 1 When Hard Questions are Asked: Evaluating Writing Centers  

E-print Network

Hard Questions 1 When Hard Questions are Asked: Evaluating Writing Centers James H. Bell University of Northern British Columbia 3333 University Way Prince George, BC Canada V2N 4Z9 RUNNING HEAD: Hard Questions Reading and Learning. Thank you to three reviewers for their revision suggestions. #12;Hard Questions 2

Northern British Columbia, University of

380

The Hard Problem of Cooperation  

PubMed Central

Based on individual variation in cooperative inclinations, we define the “hard problem of cooperation” as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring and sanctions? In a laboratory experiment we find that the answer is affirmative if the institution is imposed on the group but negative if development of the institution is left to the group to vote on. In the experiment, participants were divided into groups of either cooperative types or non-cooperative types depending on their behavior in a public goods game. In these homogeneous groups they repeatedly played a public goods game regulated by an institution that incorporated several of the key properties identified by Ostrom: operational rules, monitoring, rewards, punishments, and (in one condition) change of rules. When change of rules was not possible and punishments were set to be high, groups of both types generally abided by operational rules demanding high contributions to the common good, and thereby achieved high levels of payoffs. Under less severe rules, both types of groups did worse but non-cooperative types did worst. Thus, non-cooperative groups profited the most from being governed by an institution demanding high contributions and employing high punishments. Nevertheless, in a condition where change of rules through voting was made possible, development of the institution in this direction was more often voted down in groups of non-cooperative types. We discuss the relevance of the hard problem and fit our results into a bigger picture of institutional and individual determinants of cooperative behavior. PMID:22792282

Eriksson, Kimmo; Strimling, Pontus

2012-01-01

381

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

382

Hard Core entropy: lower bounds  

E-print Network

We establish lower bounds for the entropy of the Hard Core Model on a few 2d lattices $\\scriptstyle {\\rm {\\bf L}}.$ In this model the allowed configurations inside $\\scriptstyle \\{0,1\\}^{{\\rm {\\bf L}}}$ are the one's in which the nearest neighbor $\\scriptstyle 1$'s are forbidden. Our method which is based on a sequential fill-in scheme is unbiassed and thereby yields in principle arbitrarily good estimates for the topological entropy. The procedure also gives some detailed information on the support of the measure of maximal entropy.

Kari Eloranta

2009-07-23

383

Outer Rise Faulting And Mantle Serpentinization  

NASA Astrophysics Data System (ADS)

Dehydration of serpentinized mantle of the downgoing slab has been proposed to cause both intermediate depth earthquakes (50-300 km) and arc volcanism at sub- duction zones. It has been suggested that most of this serpentinization occurs beneath the outer rise; where normal faulting earthquakes due to bending cut > 20 km deep into the lithosphere, allowing seawater to reach and react with underlying mantle. However, little is known about flexural faulting at convergent margins; about how many normal faults cut across the crust and how deeply they penetrate into the man- tle; about the true potential of faults as conduits for fluid flow and how much water can be added through this process. We present evidence that pervasive flexural faulting may cut deep into the mantle and that the amount of faulting vary dramatically along strike at subduction zones. Flexural faulting increases towards the trench axis indicat- ing that active extension occurs in a broad area. Multibeam bathymetry of the Pacific margin of Costa Rica and Nicaragua shows a remarkable variation in the amount of flexural faulting along the incoming ocean plate. Several parameters seem to control lateral variability. Off south Costa Rica thick crust of the Cocos Ridge flexes little, and little to no faulting develops near the trench. Off central Costa Rica, normal thick- ness crust with magnetic anomalies striking oblique to the trench displays small offset faults (~200 m) striking similar to the original seafloor fabric. Off northern Costa Rica, magnetic anomalies strike perpendicular to the trench axis, and a few ~100m-offset faults develop parallel to the trench. Further north, across the Nicaraguan margin, magnetic anomalies strike parallel to the trench and the most widespread faulting de- velops entering the trench. Multichannel seismic reflection images in this area show a pervasive set of trenchward dipping reflections that cross the ~6 km thick crust and extend into the mantle to depths of at least 20 km. Some reflections project updip to offsets in top basement and seafloor, indicating that they are fault plane reflections. Such a deeply penetrating tectonic fabric could have not developed during crustal cre- ation at the paleo-spreading center where the brittle layer is few km thick. Thus, they must be created during flexure of the plate entering the trench. This data imply that deep and widespread serpentinization of the incoming lithosphere can occur when the lithosphere is strongly faulted; that the extent of lithospheric faulting is closely re- lated to the crustal structure of the incoming plate; and that the amount of lithosphere faulting can change dramatically within a hundred km distance along a trench axis.

Ranero, C. R.; Phipps Morgan, J.; McIntosh, K.; Reichert, C.

384

Shell choice in Pagurus longicarpus hermit crabs: does predation threat influence shell selection behavior?  

Microsoft Academic Search

Pagurus longicarpus hermit crabs depend on empty gastropod shells for protection against predation. Hermit crabs avoid gastropod shells in which holes have been drilled by naticid gastropods, and hermit crabs forced to occupy drilled shells are more vulnerable to predation by green crabs, Carcinus maenas. In this study, we examined the effect of predator cues on P. longicarpus shell investigation

Randi D. Rotjan; Julia Blum; Sara M. Lewis

2004-01-01

385

Developments in Cylindrical Shell Stability Analysis  

NASA Technical Reports Server (NTRS)

Today high-performance computing systems and new analytical and numerical techniques enable engineers to explore the use of advanced materials for shell design. This paper reviews some of the historical developments of shell buckling analysis and design. The paper concludes by identifying key research directions for reliable and robust methods development in shell stability analysis and design.

Knight, Norman F., Jr.; Starnes, James H., Jr.

1998-01-01

386

Asymptotically Correct Shell Model for Nuclear Fission  

Microsoft Academic Search

A two-center shell model with oscillator potentials, l-->.s--> forces, and l-->2 terms is developed. The shell structures of the original spherical nucleus and those of the final fragments are reproduced. For small separation of the two centers the level structure resembles the Nilsson scheme. This two-center shell model might be of importance in problems of nuclear fission.

D. Scharnweber; U. Mosel; W. Greiner

1970-01-01

387

Neural signals on adaptive paraboloidal cylindrical shells  

Microsoft Academic Search

Paraboloidal cylindrical shells are commonly used as key components in communication antennas, space reflectors, solar collectors, etc. This study focuses on analysis of distributed sensing signals induced by piezoelectric sensors on a flexible simply-supported paraboloidal cylindrical shell panel. The PVDF layer fully laminated on the shell panel is segmented into infinitesimal patches to investigate the characteristic of distributed neural sensing

Shun-di Hu; Hua Li; Horn-sen Tzou

2011-01-01

388

Shell mound formation in coastal northern Australia  

Microsoft Academic Search

Shell mounds are late Holocene deposits typically dominated by a single shell species. In northern Australia these mounds are associated with prograding coastal plains. The largest and most numerous are at Weipa on Cape York Peninsula. Archaeologists claim that these mounds were formed by generations of shellfishing Aborigines. This hypothesis is false because most of the shells from the type-site

Tim Stone

1995-01-01

389

Shell Formation and Bone Strength Laying Hens  

E-print Network

Shell Formation and Bone Strength in Laying Hens Effects of Age, Daidzein and Exogenous Estrogen Cover aquarelle: E. Spörndly-Nees #12;Shell Formation and Bone Strength in Laying Hens Effects of Age as well as an economical problem. Parallel with reduced shell quality the bone strength declines

390

7 CFR 984.10 - Shelled walnuts.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Shelled walnuts. 984.10 Section 984.10 Agriculture...Nuts), DEPARTMENT OF AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 984.10 Shelled walnuts. Shelled walnuts means walnut...

2010-01-01

391

Generalized approximation to seniority shell model  

Microsoft Academic Search

A generalized approximation to seniority shell model, based on the number conserving quasiparticle theory, is presented which includes the cases where both neutrons and protons are present in the valance shells. The numerical calculations are carried out for even Zr isotopes. The results obtained compare well with the corresponding exact shell model results, demonstrating thereby the validity of the present

Y. K. Gambhir; S. Haq; J. K. Suri

1979-01-01

392

Generalized approximation to seniority shell model  

Microsoft Academic Search

A generalized approximation to seniority shell model, based on the number conserving quasiparticle theory, is presented which includes the cases where both neutrons and protons are present in the valence shells. The numerical calculations are carried out for even Zr isotopes. The results obtained compare well with the corresponding exact shell model results, demonstrating thereby the validity of the present

Y. K. Gambhir; S. Haq; J. K. Suri

1979-01-01

393

Hardness correlation for uranium and its alloys  

SciTech Connect

The hardness of 16 different uranium-titanium (U-Ti) alloys was measured on six (6) different hardness scales (R/sub A/, R/sub B/, R/sub C/, R/sub D/, Knoop, and Vickers). The alloys contained between 0.75 and 2.0 wt % Ti. All of the alloys were solutionized (850/sup 0/C, 1 h) and ice-water quenched to produce a supersaturated martensitic phase. A range of hardnesses was obtained by aging the samples for various times and temperatures. The correlation of various hardness scales was shown to be virtually identical to the hardness-scale correlation for steels. For more-accurate conversion from one hardness scale to another, least-squares-curve fits were determined for the various hardness-scale correlations. 34 figures, 5 tables.

Humphreys, D L; Romig, Jr, A D

1983-03-01

394

Skin structure and cornification proteins in the soft-shelled turtle Trionyx spiniferus.  

PubMed

In contrast to most chelonians, the fully aquatic soft-shelled turtles have a smooth, unscaled, and pliable shell. The skin of the shell, tail, limbs, and neck of juveniles of Trionyx spiniferus has been studied by ultrastructural, immunocytochemical, and immunoblotting methods. The epidermis of the carapace and plastron has a thick corneous layer composed of alpha-corneocytes surrounded by a cornified cell envelope. The softer epidermis is similar to that of the shell but the epidermis and corneous layer are much thinner. Pre-corneous cells in both soft and shell epidermis are rich in vesicles produced in the Golgi apparatus and smooth endoplasmic vesicles, and contain numerous dense-core mucus-like and vesicular (lamellar) bodies. Secreted material is present among corneocytes where it probably forms an extensive intercellular lipid-mucus waterproof barrier. The dermis is very thick and composed of several layers of collagen bundles that form a plywood-patterned dermis. This dermis constitutes a strong mechanical barrier that compensates for the low content in beta-keratin, and lack of cornified scutes and dermal bones. The growth of the shell mainly occurs along the lateral margins. Immunocytochemistry reveals the presence of some beta-keratin in soft and shell epidermis, and this is confirmed by immunoblotting where bands at 18 and 32-35 kDa are present. Other proteins of the cornified cell envelope (loricrin and sciellin) or associated to lipid trafficking (caveolin-1) are also detected by immunoblotting. Loricrin positive bands at 24 and 57 kDa are present while bands cross-reactive for sciellin are seen at 45 and 53 kDa. Caveolin-1 positive bands are seen at 21-22 kDa. The presence of these proteins indicates that the epidermis is both coriaceous and waterproof. These results suggest that the shell of Trionyx is tough enough to be as mechanically efficient as the hard shell of the other turtles. At the same time, a soft shell is lighter, its shape is more easily controlled by muscles, and it allows a more controlled closure and retraction of limbs and neck inside the shell. Thus, the shell makes the animal more streamlined for swimming. PMID:16600580

Alibardi, Lorenzo; Toni, Mattia

2006-01-01

395

Integral shell mirrors for the Constellation X-ray mission hard x-ray telescope  

Microsoft Academic Search

Estimates of background in CZT detectors indicate that even with the beneficial concentration of a focussing telescope measurements in the 20 to 100 keV band of the Constellation X- ray Mission's HXT will become background limited after several thousand seconds of observing. This time is less than the expected exposure of most measurements. Consequently the sensitivity of most if not

Paul Gorenstein; Adrian Ivan; Ricardo J. Bruni; Suzanne E. Romaine; Franco Mazzoleni; Giovanni Pareschi; Mauro Ghigo; Oberto Citterio

2000-01-01

396

Collision safety of a hard-shell low-mass vehicle  

Microsoft Academic Search

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,

Robert Kaeser; Felix H. Walz; Anton Brunner

1994-01-01

397

Quintuple-shelled SnO(2) hollow microspheres with superior light scattering for high-performance dye-sensitized solar cells.  

PubMed

Quintuple-shelled SnO2 hollow microspheres are prepared by a hard-template method. DSSCs constructed with SnO2 multi-shell photoanodes show a record photoconversion efficiency of 7.18% due to enhanced light scattering. SnO2 hollow microspheres that are utilized as a scattering layer on top of P25 films increase the DSSC photoconversion efficiency from 7.29% to 9.53%. PMID:24510664

Dong, Zhenghong; Ren, Hao; Hessel, Colin M; Wang, Jiangyan; Yu, Ranbo; Jin, Quan; Yang, Mei; Hu, Zhudong; Chen, Yunfa; Tang, Zhiyong; Zhao, Huijun; Wang, Dan

2014-02-12

398

Probing Strangeness in Hard Processes  

E-print Network

Since the discovery of strangeness almost five decades ago, interest in this degree of freedom has grown up and now its investigation spans the scales from quarks to nuclei. Measurements with identified strange hadrons can provide important information on several hot topics in hadronic physics: the strange distribution and fragmentation functions, the nucleon tomography and quark orbital momentum, accessible through the study of the {\\it generalized} parton distribution and the {\\it transverse momentum dependent} parton distribution functions, the quark hadronization in the nuclear medium, the hadron spectroscopy and the search for exotic mesons. The CLAS12 large acceptance spectrometer in Hall B at the Jefferson Laboratory upgraded with a RICH detector together with the 12 GeV CEBAF high intensity, high polarized electron beam can open new possibilities to study strangeness in hard processes allowing breakthroughs in all those areas. This paper summarizes the physics case for a RICH detector for CLAS12. Many topics have been intensively discussed at the International Workshop "Probing Strangeness in Hard Processes" (PSHP2010) \\cite{PSHP-workshop} held in Frascati, Italy in October 2010. The authors of this papers like to thank all speakers and participants of the workshop for their contribution and very fruitful discussion.

H. Avakian; M. Battaglieri; E. Cisbani; M. Contalbrigo; U. D'Alesio; R. De Leo; R. Devita; P. Di Nezza; D. Hasch; V. Kubarovsky; M. Mirazita; M. Osipenko; L. Pappalardo; P. Rossi

2012-02-09

399

Hard and Soft Safety Verifications  

NASA Technical Reports Server (NTRS)

The purpose of this paper is to examine the differences between and the effects of hard and soft safety verifications. Initially, the terminology should be defined and clarified. A hard safety verification is datum which demonstrates how a safety control is enacted. An example of this is relief valve testing. A soft safety verification is something which is usually described as nice to have but it is not necessary to prove safe operation. An example of a soft verification is the loss of the Solid Rocket Booster (SRB) casings from Shuttle flight, STS-4. When the main parachutes failed, the casings impacted the water and sank. In the nose cap of the SRBs, video cameras recorded the release of the parachutes to determine safe operation and to provide information for potential anomaly resolution. Generally, examination of the casings and nozzles contributed to understanding of the newly developed boosters and their operation. Safety verification of SRB operation was demonstrated by examination for erosion or wear of the casings and nozzle. Loss of the SRBs and associated data did not delay the launch of the next Shuttle flight.

Wetherholt, Jon; Anderson, Brenda

2012-01-01

400

A Particle Simulation for the Pulsar Magnetosphere: Relationship of Polar Cap, Slot Gap, and Outer Gap  

NASA Astrophysics Data System (ADS)

To explain the pulsed emission of the rotation powered pulsars from radio to gamma-ray, polar cap models, slot gap models, and outer gap models are proposed. Recent observations suggest that these models are likely to co-exist in the same magnetosphere. If so, their mutual relation is known to be troublesome (Harding 2009), due to the boundary conditions and the direction of the current, which are properly assumed in each acceleration model. We performed a particle simulation for the global magnetospheric structure. Based on this simulation, we present a new picture of the global structure of the pulsar magnetosphere. It is found that a new dead zone is formed along the current neutral line that separates the oppositely directed current. We shall call this the current-neutral zone. We suggest that the polar cap accelerators and the slot gaps locate above the current-neutral zone, and the outer gap exist between the current neutral zone and the traditional dead zone. We also give an estimate of the super-rotation region.

Yuki, Shinya; Shibata, Shinpei

2012-06-01

401

Bax inserts into the mitochondrial outer membrane by different mechanisms.  

PubMed

Bax insertion into the mitochondrial outer membrane is essential for the implementation of apoptosis. However, little is known about the first stage of Bax integration into the mitochondrial outer membrane. We have recently shown that TOM22, a mitochondrial outer membrane receptor, is important for insertion, although other reports have suggested that only mitochondrial lipids are involved in this process. Here, we show that monomers, but not dimers, of Bax require the presence of TOM22 and TOM40 to integrate into mitochondria. In addition we show that once inserted into the membrane, Bax can act as a receptor for cytosolic Bax. PMID:18687331

Cartron, Pierre-François; Bellot, Grégory; Oliver, Lisa; Grandier-Vazeille, Xavier; Manon, Stephen; Vallette, François M

2008-09-01

402

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

403

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

404

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

405

Modeling cross L shell impacts of magnetopause shadowing and ULF wave radial diffusion in the Van Allen belts  

NASA Astrophysics Data System (ADS)

present simulations of the outer electron radiation belt using a new ULF wave-driven radial diffusion model, including empirical representations of loss due to chorus and plasmaspheric hiss. With an outer boundary condition constrained by in situ electron flux observations, we focus on the impacts of magnetopause shadowing and outward radial diffusion in the heart of the radiation belt. Third invariant conserving solutions are combined to simulate the L shell and time dependence of the differential flux at a fixed energy. Results for the geomagnetically quiet year of 2008 demonstrate not only remarkable cross L shell impacts from magnetopause shadowing but also excellent agreement with the in situ observations even though no internal acceleration source is included in the model. Our model demonstrates powerful utility for capturing the cross-L impacts of magnetopause shadowing with significant prospects for improved space weather forecasting. The potential role of the plasmasphere in creating a third belt is also discussed.

Ozeke, Louis G.; Mann, Ian R.; Turner, Drew L.; Murphy, Kyle R.; Degeling, Alex W.; Rae, I. Jonathan; Milling, David K.

2014-10-01

406

Facile synthesis of yolk-shell magnetic mesoporous carbon microspheres for efficient enrichment of low abundance peptides.  

PubMed

Magnetic mesoporous carbon microspheres with a yolk-shell structure (YSMMCS) have been prepared via a new in situ carbon source strategy. The material was fabricated by two shells coated onto the Fe3O4 particles; the inner dense and thick silica shell could protect the magnetic core from harsh acidic solvents as well as induce the void between the core and the outer shell for the yolk-shell structure, while the outer organosilica shell was used as the template and carbon source for in situ preparation of a carbon shell with mesoporous structure. A C18-alkyl chain was incorporated in situ as the carbon precursor efficiently, avoiding the conventional infiltration step, which was very difficult to manipulate and time-consuming with the possibility of losing the carbon precursor. The resulting yolk-shell magnetic mesoporous carbon microspheres exhibited a high surface area (273.15 m(2) g(-1)), a large pore volume (0.31 cm(3) g(-1)), and a strong magnetic response (a saturation magnetization value of 34.57 emu g(-1)). As a result of the void between the core and the outer shell and the ?-? stacking effect, adsorption capacity reached 191.64 mg g(-1) by using Rhodamine B as a standard analyte, indicating the great potential application of the material as drug carriers. Owing to the inherent hydrophobicity and high surface area, the composite material showed better performance in the enrichment of peptides than a magnetic mesoporous silica material (Fe2O3@nSiO2@mSiO2). According to the LC-MS/MS results, about 51 and 29 nonredundant peptides were identified from tryptic digests of 5 nM BSA. Additionally, taking advantage of the mesoporous structure and strong magnetic response, the material was utilized to selectively extract low abundance endogenous peptides from human serum in the presence of high abundance proteins. Based on the LC-MS/MS results, 962 endogenous peptides were obtained by 2.5 mg YSMMCS relative to 539 endogenous peptides by 5 mg Fe2O3@nSiO2@mSiO2, confirming the outstanding performance of YSMMCS in peptidome analysis. PMID:24061763

Wan, Hao; Qin, Hongqiang; Xiong, Zhichao; Zhang, Weibing; Zou, Hanfa

2013-11-21

407

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

408

Geometrical and crystallographic constraints determine the self-organization of shell microstructures in Unionidae (Bivalvia: Mollusca).  

PubMed

Unionid shells are characterized by an outer aragonitic prismatic layer and an inner nacreous layer. The prisms of the outer shell layer are composed of single-crystal fibres radiating from spheruliths. During prism development, fibres progressively recline to the growth front. There is competition between prisms, leading to the selection of bigger, evenly sized prisms. A new model explains this competition process between prisms, using fibres as elementary units of competition. Scanning electron microscopy and X-ray texture analysis show that, during prism growth, fibres become progressively orientated with their three crystallographic axes aligned, which results from geometric constraints and space limitations. Interestingly transition to the nacreous layer does not occur until a high degree of orientation of fibres is attained. There is no selection of crystal orientation in the nacreous layer and, as a result, the preferential orientation of crystals deteriorates. Deterioration of crystal orientation is most probably due to accumulation of errors as the epitaxial growth is suppressed by thick or continuous organic coats on some nacre crystals. In conclusion, the microstructural arrangement of the unionid shell is, to a large extent, self-organized with the main constraints being crystallographic and geometrical laws. PMID:11321067

Checa, A G; Rodríguez-Navarro, A

2001-04-01

409

Shell Model Approach to Nuclear Level Density  

NASA Astrophysics Data System (ADS)

Nuclear level densities (NLD) are traditionally estimated using variations of Fermi Gas Formula (FGF) or combinatoric techniques. Recent investigations using Monte Carlo Shell Model (MCSM) techniques indicate that a shell model description of NLD may be an accurate and stable approach. Full shell model calculations of NLD are very difficult. We calculated the NLD for all nuclei in the sd shell and show that the results can be described by a single particle combinatoric model, which depends on two parameters similar to FGF. We further investigated other models and find that a sum of gaussians with means and variances given by French and Ratcliff averages (Phys. Rev. C 3, 94(1971)) is able to accurately describe shell model NLD, even when shell effects are present. The contribution of the spurious center-of-mass motion to the shell model NLD is also discussed.

Horoi, Mihai

2000-04-01

410

Shell Evolutions and Nuclear Forces  

NASA Astrophysics Data System (ADS)

During the last 30 years, and more specifically during the last 10 years, many experiments have been carried out worldwide using different techniques to study the shell evolution of nuclei far from stability. What seemed not conceivable some decades ago became rather common: all known magic numbers that are present in the valley of stability disappear far from stability and are replaced by new ones at the drip line. By gathering selected experimental results, beautifully consistent pictures emerge, that very likely take root in the properties of the nuclear forces.The present manuscript describes some of these discoveries and proposes an intuitive understanding of these shell evolutions derived from observations. Extrapolations to yet unstudied regions, as where the explosive r-process nucleosynthesis occurs, are proposed. Some remaining challenges and puzzling questions are also addressed.

Sorlin, O.

2014-03-01

411

Comparative Proteome Analysis of Spontaneous Outer Membrane Vesicles and Purified Outer Membranes of Neisseria meningitidis  

PubMed Central

Outer membrane vesicles (OMVs) of Gram-negative bacteria receive increasing attention because of various biological functions and their use as vaccines. However, the mechanisms of OMV release and selective sorting of proteins into OMVs remain unclear. Comprehensive quantitative proteome comparisons between spontaneous OMVs (SOMVs) and the outer membrane (OM) have not been conducted so far. Here, we established a protocol for metabolic labeling of neisserial proteins with 15N. SOMV and OM proteins labeled with 15N were used as an internal standard for proteomic comparison of the SOMVs and OMs of two different strains. This labeling approach, coupled with high-sensitivity mass spectrometry, allowed us to comprehensively unravel the proteome of the SOMVs and OMs. We quantified the relative distribution of 155 proteins between SOMVs and the OM. Complement regulatory proteins, autotransporters, proteins involved in iron and zinc acquisition, and a two-partner secretion system were enriched in SOMVs. The highly abundant porins PorA and PorB and proteins connecting the OM with peptidoglycan or the inner membrane, such as RmpM, MtrE, and PilQ, were depleted in SOMVs. Furthermore, the three lytic transglycosylases MltA, MltB, and Slt were less abundant in SOMVs. In conclusion, SOMVs are likely to be released from surface areas with a low local abundance of membrane-anchoring proteins and lytic transglycosylases. The enrichment of complement regulatory proteins, autotransporters, and trace metal binding and transport proteins needs to be explored in the context of the pathogenesis of meningococcal disease. PMID:23893116

Otto, Andreas; Becher, Dorte; Vogel, Ulrich

2013-01-01

412

An Outer-Inner Approximation for separable MINLPs  

E-print Network

Outer approximation consists in building a mixed-integer linear ... and constraints can be cast into that form by introducing an extra variable and moving the objective ...... On the implementation of a primal-dual interior point filter line search.

2011-06-03

413

Transport of proteins across or into the mitochondrial outer membrane.  

PubMed

Mitochondria are surrounded by two biological membranes. The outer mitochondrial membrane contains two major translocators, the TOM40 (TOM) and TOB/SAM complexes for protein translocation across and/or insertion into the outer membrane. The TOM40 complex functions as an entry gate for most mitochondrial proteins, and the TOB/SAM complex as a specialized insertion machinery for beta-barrel membrane proteins. In order to handle loosely folded or unfolded precursor polypeptides, those translocators cooperate with chaperones in the cytosol and intermembrane space, and also exhibit chaperone-like functions on their own. Several alpha-helical membrane proteins take 'non-standard' routes to be inserted into the outer membrane. Here we review the current view on a remarkable variety of mechanisms of protein transport taking place at the mitochondrial outer membrane. PMID:19945489

Endo, Toshiya; Yamano, Koji

2010-06-01

414

OUTER RIM OF CIRCLE, WITH LIVE OAK TREE AT LEFT ...  

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

OUTER RIM OF CIRCLE, WITH LIVE OAK TREE AT LEFT FOREGROUND AND CEMETERY SECTION 25 IN BACKGROUND. VIEW TO WEST. - Barrancas National Cemetery, Naval Air Station, 80 Hovey Road, Pensacola, Escambia County, FL

415

Nuclear power sources in outer space. [spacecraft propulsion legal aspects  

NASA Technical Reports Server (NTRS)

Legal problems associated with nuclear power sources in space are discussed with particular reference to the Cosmos 954 incident. Deliberations of the Legal and Scientific and Technical Subcommittees on the Peaceful Uses of Outer Space on this subject are discussed.

Hosenball, S. N.

1978-01-01

416

Upper atmospheres and diagnostic measurements. [for outer planet atmospheric studies  

NASA Technical Reports Server (NTRS)

Candidate space missions to study the temperature profiles, and ratios of hydrogen to helium in outer planet atmospheres are discussed in terms of scientific payloads for optical occultation, radio occultation, and thermometer measurements.

Hunten, D.

1974-01-01

417

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.

Brewster, Vanessa

2012-07-27

418

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

419

Outer hair cell piezoelectricity: frequency response enhancement and resonance behavior.  

PubMed

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

2003-09-01

420

Star Formation in the Outer Disk of Spiral Galaxies  

NASA Astrophysics Data System (ADS)

We combine new deep and wide field of view H? imaging of a sample of eight nearby (d ? 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 ~10-5 to 10-6 M ? yr-1 kpc-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 gsim85%. 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 ~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; Côté, Stéphanie; Schade, David

2012-09-01

421

Stability of mono- and trivalent meningococcal outer membrane vesicle vaccines  

Microsoft Academic Search

The stability during storage of outer membrane vesicles (OMVs) of Neisseria meningitidis group B was studied. Three types of OMVs were compared for their stability, containing either one (monovalent) or three different PorA subtypes (trivalent), the latter with and without class 4 outer membrane protein (OMO, RmpM).Aqueous formulations were stored freeze-dried (4°C), frozen (?70°C) and in liquid form at 4,

Carmen Arigita; Wim Jiskoot; Janny Westdijk; Cor van Ingen; Wim E. Henninka; Daan J. A. Crommelin; Gideon F. A. Kersten

2004-01-01

422

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

423

Probing Strangeness in Hard Processes  

E-print Network

Since the discovery of strangeness almost five decades ago, interest in this degree of freedom has grown up and now its investigation spans the scales from quarks to nuclei. Measurements with identified strange hadrons can provide important information on several hot topics in hadronic physics: the strange distribution and fragmentation functions, the nucleon tomography and quark orbital momentum, accessible through the study of the {\\it generalized} parton distribution and the {\\it transverse momentum dependent} parton distribution functions, the quark hadronization in the nuclear medium, the hadron spectroscopy and the search for exotic mesons. The CLAS12 large acceptance spectrometer in Hall B at the Jefferson Laboratory upgraded with a RICH detector together with the 12 GeV CEBAF high intensity, high polarized electron beam can open new possibilities to study strangeness in hard processes allowing breakthroughs in all those areas. This paper summarizes the physics case for a RICH detector for CLAS12. Many...

Avakian, H; Cisbani, E; Contalbrigo, M; D'Alesio, U; De Leo, R; Devita, R; Di Nezza, P; Hasch, D; Mirazita, M; Osipenko, M; Pappalardo, L; Rossi, P

2012-01-01

424

Hard-gapped Holographic Superconductors  

E-print Network

In this work we discuss the zero temperature limit of a "p-wave" holographic superconductor. The bulk description consists of a non-Abelian SU(2) gauge fields minimally coupled to gravity. We numerically construct the zero temperature solution which is the gravity dual of the superconducting ground state of the "p-wave" holographic superconductors. The solution is a smooth soliton with zero horizon size and shows an emergent conformal symmetry in the IR. We found the expected superconducting behavior. Using the near horizon analysis we show that the system has a "hard gap" for the relevant gauge field fluctuations. At zero temperature the real part of the conductivity is zero for an excitation frequency less than the gap frequency. This is in contrast with what has been observed in similar scalar- gravity-gauge systems (holographic superconductors). We also discuss the low but finite temperature behavior of our solution.

Pallab Basu; Jianyang He; Anindya Mukherjee; Hsien-Hang Shieh

2009-11-26

425

Atomic inner-shell transitions  

NASA Technical Reports Server (NTRS)

Atomic inner-shell processes have quite different characteristics, in several important aspects, from processes in the optical regime. Energies are large, e.g., the 1s binding energy reaches 100 keV at Z = 87; relativistic and quantum-electrodynamic effects therefore are strong. Radiationless transitions vastly dominate over photon emission in most cases. Isolated inner-shell vacancies have pronounced single-particle character, with correlations generally contributing only approximately 1 eV to the 1s and 2p binding energies; the structure of such systems is thus well tractable by independent-particle self-consistent-field atomic models. For systems containing multiple deep inner-shell vacancies, or for highly stripped ions, the importance of relativistic intermediate coupling and configuration interaction becomes pronounced. Cancellation of the Coulomb interaction can lead to strong manifestations of the Breit interaction in such phenomena as multiplet splitting and hypersatellite X-ray shifts. Unique opportunities arise for the test of theory.

Crasemann, B.; Chen, M. H.; Mark, H.

1984-01-01

426

Separation of inner and outer membranes of Rhodopseudomonas spheroides.  

PubMed

The separation of inner and outer membrane of Rhodopseudomonas spheroides has been achieved by means of sucrose density gradient (20%, 40%, 60%, w/w) centrifugation. The upper fraction of the gradient, with a specific density 1.181 (g/cm3), is high in cytochrome and succinate dehydrogenase activities, low in lipopolysaccharides and it is designated the inner membrane fraction. The bottom fraction of the gradient, with a specific density 1.240, is high in lipopolysaccharide and contains neither cytochrome nor succinate dehydrogenase activities. This fraction is the cell wall or outer membrane fraction. The intermediate band on the gradient is an unseparated fraction of inner and outer membrane fragments. This fraction has a specific denisty of 1.211 and represents less than 3% of total crude envelope. Thin sections of the vesicles of the inner membrane fraction and those of outer membrane provide morphological evidence for the identity of the individual membrane fractions. At least 22 protein bands are resolved by employing sodium dodecyl sulfate slab gel electrophoresis. Six bands are present only in the inner membrane and two bands are found exclusively in the outer membrane. Most of the remaining polypeptides are present in greater amounts in the inner membrane relative to the outer membrane fractions. PMID:1083979

Ding, D H; Kaplan, S

1976-01-01

427

Proteome analysis of mitochondrial outer membrane from Neurospora crassa  

SciTech Connect

The mitochondrial outer membrane mediates numerous interactions between the metabolic and genetic systems of mitochondria and the rest of the eukaryotic cell. We performed a proteomic study to discover novel functions of components of the mitochondrial outer membrane. Proteins of highly pure outer membrane vesicles (OMV) from Neurospora crassa were identified by a combination of liquid chromatography tandem mass spectrometry of tryptic peptide digests and gel electrophoresis of solubilized OMV proteins, followed by their identification using MALDI-MS peptide fingerprinting. Among the 30 proteins found in at least three of four separate analyses were 23 proteins with known functions in the outer membrane. These included components of the import machinery (the TOM and TOB complexes), a pore-forming component (Porin), and proteins that control fusion and fission of the organelle. In addition, proteins playing a role in various biosynthetic pathways, whose intracellular location had not been established previously, could be localized to the mitochondrial outer membrane. Thus, the proteome of the outer membrane can help in identifying new mitochondria-related functions.

Schmitt, Simone; Prokisch, Holger; Schlunk, Tilman; Camp, David G.; Ahting, Uwe; Waizenegger, Thomas; Scharfe, Curt M.; Meitinger, Thomas; Imhof, Axel; Neupert, Walter; Oefner, Peter J.; Rapaport, Doron

2006-01-01

428

Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (south Atlantic): Hard clam. [Mercenaria mercenaria  

SciTech Connect

The hard clam, Mercenaria mercenaria, supports an important commercial fishery in the South Atlantic, averaging about 1 million kg of meats annually from 1979 to 1983. It also is an important constituent of estuarine systems throughout the region. Spawning occurs in the spring and the fall at 16 to 30/sup 0/C. Planktonic eggs and larvae are carried by water currents, and larvae set sometime after 6 days of age. Mortality is highest in egg and larval stages, the most sensitive part of the life cycle. Spat display gregarious setting behavior and appear to select sand over finer substrates. Highest densities of clams occur in sandy bottoms with shell. Crab predation is an important factor influencing the density and distribution of clams. Blue crabs and mud crabs appear to be the most important predators. Hard clams are infested by few parasites. Adult clams feed by filtering suspended particulate matter from the water. Growth of clams decreases with size and age. Growth occurs year-round with peaks in spring and fall. Growth of adult hard clams occurs at 9 to 31/sup 0/C and at 4 to 35 ppt (optima near 20/sup 0/C and 24 to 28 ppt). Hard clams mature in 2 years and reach commercial size in 3 years in the South Atlantic. Tight-fitting shells permit hard clams to survive poor water quality for short periods.

Eversole, A.G.

1987-08-01

429

Estimation of calcified tissues hardness via calcium and magnesium ionic to atomic line intensity ratio in laser induced breakdown spectra  

NASA Astrophysics Data System (ADS)

Calcified tissues representing three different matrices, namely enamel of human teeth, shells and eggshell, have been studied via Laser Induced Breakdown Spectroscopy (LIBS) technique. The experimental CaII/CaI and MgII/MgI ratios have been measured, in view of the expected correlation between the extent of ionization caused by the laser induced shock wave (SW) and the hardness of the target. The ratio CaII/CaI between the ionic calcium line at 373.69 nm and the neutral line at 428.9 nm is obtained for enamel, shells and eggshell spectra, as well as the ratio MgII/MgI between the ionic magnesium line at 280.26 nm and the neutral line at 285.22 nm. The results show that such spectral lines intensities ratio differs for different matrices and is indeed related to the target materials hardness. It is also found that the MgII/MgI ratio is preferable as an indicator of hardness since these lines are less affected by self absorption. The SW front speed has been measured in the three cases and the obtained values confirm the proportionality to the target hardness. The results here obtained suggest the feasibility of the quantitative estimation of hardness for any other calcified tissues.

Abdel-Salam, Z. A.; Galmed, A. H.; Tognoni, E.; Harith, M. A.

2007-12-01

430

On growth and form of irregular coiled-shell of a terrestrial snail: Plectostoma concinnum (Fulton, 1901) (Mollusca: Caenogastropoda: Diplommatinidae).  

PubMed

The molluscan shell can be viewed as a petrified representation of the organism's ontogeny and thus can be used as a record of changes in form during growth. However, little empirical data is available on the actual growth and form of shells, as these are hard to quantify and examine simultaneously. To address these issues, we studied the growth and form of a land snail that has an irregularly coiled and heavily ornamented shell-Plectostoma concinnum. The growth data were collected in a natural growth experiment and the actual form changes of the aperture during shell ontogeny were quantified. We used an ontogeny axis that allows data of growth and form to be analysed simultaneously. Then, we examined the association between the growth and the form during three different whorl growing phases, namely, the regular coiled spire phase, the transitional constriction phase, and the distortedly-coiled tuba phase. In addition, we also explored the association between growth rate and the switching between whorl growing mode and rib growing mode. As a result, we show how the changes in the aperture ontogeny profiles in terms of aperture shape, size and growth trajectory, and the changes in growth rates, are associated with the different shell forms at different parts of the shell ontogeny. These associations suggest plausible constraints that underlie the three different shell ontogeny phases and the two different growth modes. We found that the mechanism behind the irregularly coiled-shell is the rotational changes of the animal's body and mantle edge with respect to the previously secreted shell. Overall, we propose that future study should focus on the role of the mantle and the columellar muscular system in the determination of shell form. PMID:24883245

Liew, Thor-Seng; Kok, Annebelle C M; Schilthuizen, Menno; Urdy, Severine

2014-01-01

431

Analysis of hard carbon for lithium-ion batteries by hard X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

Non-graphitizable carbon (hard carbon) as a negative electrode material for lithium-ion batteries is investigated by X-ray photoelectron spectroscopy, and hard X-ray photoelectron spectroscopy (HX-PES). HX-PES spectra have peaks of both the solid electrolyte interphase on the hard carbon surface and the hard carbon itself. The change in spectrum with state of charge is observed by HX-PES. Hard carbon has two types of lithium insertion site; between graphene sheets and into nano-scale voids. These spectroscopic results are consistent with the lithium insertion mechanism into hard carbon.

Hori, Hironobu; Shikano, Masahiro; Kobayashi, Hironori; Koike, Shinji; Sakaebe, Hikari; Saito, Yoshiyasu; Tatsumi, Kuniaki; Yoshikawa, Hideki; Ikenaga, Eiji

2013-11-01

432

A study of the Texas hard clam: distribution and growth of Mercenaria mercenaria texana in Texas bays  

E-print Network

coast. 3. To follow survival and growth of M. mercenaria seed and N. mercenaria texana seed planted in two Texas bays, Christmas Bay and Redfish Bay. The first objective of this study was to describe the hard clam population in Christmas bay... was used to estimate ages for older clams in which the number of annual bands in the shell was difficult to distinguish. Other ~ba s To compare growth rates of hard clams from different bays, N. mercenaria texana were collected from 3 other bays along...

Craig, M. Alison

2012-06-07

433

77 FR 10707 - Safety Zone; NOBLE DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort Seas, Alaska  

Federal Register 2010, 2011, 2012, 2013

...Zone; NOBLE DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort...Chukchi and Beaufort Seas Outer Continental Shelf, Alaska, from 12:01 a...Chukchi and Beaufort Seas Outer Continental Shelf, Alaska during the 2012...

2012-02-23

434

75 FR 51950 - Outer Continental Shelf Air Regulations Consistency Update for Massachusetts  

Federal Register 2010, 2011, 2012, 2013

...A-1-FRL-9167-7] Outer Continental Shelf Air Regulations Consistency...update to a portion of the Outer Continental Shelf (``OCS'') Air Regulations...control air pollution from Outer Continental Shelf (OCS) sources in order...

2010-08-24

435

77 FR 57572 - Notice of Arrival on the Outer Continental Shelf  

Federal Register 2010, 2011, 2012, 2013

...Notice of Arrival on the Outer Continental Shelf AGENCY: Coast Guard, DHS...Arrival (NOA) on the Outer Continental Shelf (OCS). The Coast Guard NOA-OCS...Arrival (NOA) on the Outer Continental Shelf (OCS) final rule...

2012-09-18

436

75 FR 18404 - Safety Zone; FRONTIER DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort Sea...  

Federal Register 2010, 2011, 2012, 2013

...FRONTIER DISCOVERER, Outer Continental Shelf Drillship, Chukchi and Beaufort...Chukchi and Beaufort Sea Outer Continental Shelf, Alaska, during the 2010 drilling...FRONTIER DISCOVERER, Outer Continental Shelf Drillship, Chukchi and...

2010-04-12

437

78 FR 59263 - Outer Continental Shelf Air Regulations Consistency Update for California  

Federal Register 2010, 2011, 2012, 2013

...OAR-2004-0091; FRL-9831-2] Outer Continental Shelf Air Regulations Consistency...finalizing the update of the Outer Continental Shelf (``OCS'') Air Regulations...dioxide, Nitrogen oxides, Outer continental shelf, Ozone, Particulate...

2013-09-26

438

76 FR 7518 - Outer Continental Shelf Air Regulations Consistency Update for Alaska  

Federal Register 2010, 2011, 2012, 2013

...EPA-R10-OAR-2011-0045; FRL-9265-3] Outer Continental Shelf Air Regulations Consistency...update a portion of the Outer Continental Shelf (``OCS'') Air Regulations...dioxide, Nitrogen oxides, Outer Continental Shelf, Ozone, Particulate...

2011-02-10

439

26 CFR 301.9001 - Statutory provisions; Outer Continental Shelf Lands Act Amendments of 1978.  

Code of Federal Regulations, 2010 CFR

...Statutory provisions; Outer Continental Shelf Lands Act Amendments of 1978...Statutory provisions; Outer Continental Shelf Lands Act Amendments of 1978. Section 302 of the Outer Continental Shelf Lands Act Amendments of...

2010-04-01

440

26 CFR 301.9001 - Statutory provisions; Outer Continental Shelf Lands Act Amendments of 1978.  

Code of Federal Regulations, 2012 CFR

...Statutory provisions; Outer Continental Shelf Lands Act Amendments of 1978...Statutory provisions; Outer Continental Shelf Lands Act Amendments of 1978. Section 302 of the Outer Continental Shelf Lands Act Amendments of...

2012-04-01

441

76 FR 5189 - BOEMRE Information Collection Activities: 1010-0081, Operations in the Outer Continental Shelf...  

Federal Register 2010, 2011, 2012, 2013

...1010-0081, Operations in the Outer Continental Shelf for Minerals Other Than Oil...282, Operations in the Outer Continental Shelf for Minerals Other than Oil...282, Operations in the Outer Continental Shelf for Minerals Other than...

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