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This frequently-asked-questions feature provides answers about earthquakes, faults, plate tectonics, and earth structure. Maps and diagrams are provided with some answers, and links to additional information and to related topics are included.

UK PubMed Central (United Kingdom)

Sequence-directed variations in the canonical DNA double helix structure that retain Watson-Crick base-pairing play important roles in DNA recognition, topology, and nucleosome positioning....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

For the reuse of a waste salt from an electrorefining process of a spent oxide fuel, a separation of rare earth elements by an oxidative precipitation in a LiCl-KCl molten salt was tested without using precipitate agents. From the results obtained from the thermochemical calculations by HSC Chemistry software, the most stable rare earth compounds in the oxygen-used rare earth chlorides system were oxychlorides (EuOCl, NdOCl, PrOCl) and oxides (CeO{sub 2}, PrO{sub 2}), which coincide well with results of the Gibbs free energy of the reaction. In this study, similar to the thermochemical results, regardless of the sparging time and molten salt temperature, oxychlorides and oxides were formed as a precipitant by a reaction with oxygen. The structure of the rare earth precipitates was divided into two shapes: small cubic (oxide) and large plate-like (tetragonal) ...

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For the reuse of a waste salt from an electrorefining process of a spent oxide fuel, a separation of rare earth elements by an oxidative precipitation in a LiCl-KCl molten salt was tested without using precipitate agents. From the results obtained from the thermochemical calculations by HSC Chemistry software, the most stable rare earth compounds in the oxygen-used rare earth chlorides system were oxychlorides (EuOCl, NdOCl, PrOCl) and oxides (CeO2, PrO2), which coincide well with results of the Gibbs free energy of the reaction. In this study, similar to the thermochemical results, regardless of the sparging time and molten salt temperature, oxychlorides and oxides were formed as a precipitant by a reaction with oxygen. The structure of the rare earth precipitates was divided into two sha...

Energy Technology Data Exchange (ETDEWEB)

The impact properties of high-strength low alloy TRIP steels such as 'TRIP-aided dual-phase steel' and 'TRIP-aided bainitic steel' associated with the transformation-induced plasticity (TRIP) of retained austenite were investigated for some applications to the automotive impact members. The TRIP steels possessed far higher impact absorbed value and lower ductile-brittle transition temperature than the conventional ferrite-martensite and ferrite-pearlite steels. The stress relaxation resulting from the strain-induced transformation of retained austenite islands or films improved the impact properties in terms of suppressing void and/or crack initiation and these propagation. The best impact properties were completed in the steel composing of uniform fine bainitic lath structure and a large amount of stable interlath retained austenite films. (author)

British Library Electronic Table of Contents (United Kingdom)

Abstract The creation of chirality on Earth and the development of chiral life have been discussed in this highlight. Convincing evidence for the introduction of chirality on Earth is still fragmentary. We believe that by a combination of chiral crystallization and formation of helical polymers with preferred chiral conformational structure is the key to this question. This concept of macromolecular asymmetry has inspired ideas and resulted in possible rules for how chiral life as we know it, could have been introduced. These investigations needed the understanding of the requirements for chiral crystallization, for the stereochemistry of the initial formation of helical polymers, the measurements of optical activity of solids and their coordination with the fundamentals of chirality. Spac...

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The thermodynamic characteristics of adsorption on the surface of graphitized thermal carbon black at 300 K were determined by the molecular statistical method for three phenylalklylamines. The influence of the intramolecular H-bond on the conformation of the molecules compared with structurally related n-alkyl-benzenes was considered. It was shown that the conformations of the molecules could influence chromatographic retention. Conformational isomers stabilized by intramolecular H-bonds were found to retain their structure in adsorption on graphitized thermal carbon black.

British Library Electronic Table of Contents (United Kingdom)

Porous SnO2 nanotubes were prepared via electrospinning followed by calcination in air. As anode materials for lithium ion batteries, the porous nanotubes delivered a high discharge capacity of 807mAhg^-^1 after 50cycles. Even after cycled at high rates, the electrode still retained a high fraction of its theoretical capacity. Such excellent performances of porous SnO2 nanotubes could be attributed to the porous and hollow structure which facilitated liquid electrolyte diffusion into the bulk materials and buffered large volume changes during lithium ions insertion/extraction. Furthermore, the nanoparticles of nanotubes provided the shorter diffusion length for lithium ions insertion which benefited in retaining the structural stability and good rate performance. Our results demonstrated t...

International Nuclear Information System (INIS)

Silicon/carbon composite anode materials were prepared by pyrolyzing the phenol-formaldehyde resin (PFR) mixed with silicon and graphite powders. Scanning electron microscopic (SEM) observation showed that the morphology stability of the composite electrodes can be retained during cycling. A structure evolution mechanism is proposed to illuminate the enhancement of cycleability of the composite electrode. The composite used as anode material for lithium ion batteries possesses a reversible capacity of over 700 mAh/g.

International Nuclear Information System (INIS)

The desire to study negative ion structure and negative ion-photon interactions has spurred the development of ion sources for use in research and industry. The many different types of negative ion sources available today differ in their characteristics and abilities to produce anions of various species. Thus the importance of choosing the correct type of negative ion source for a particular research or industrial application is clear. In this study, the results of an investigation on the production of beams composed of negatively-charged rare-earth ions from a cylindrical-cathode-geometry, cesium-sputter-type negative ion source are presented. Beams of atomic anions have been observed for most of the first-row rare-earth elements, with typical currents ranging from hundreds of picoamps to several nanoamps.

Energy Technology Data Exchange (ETDEWEB)

To study the plasma evolution and spatial structure at the L/H transition, the double hysteresis is examined by use of the 1-dimensional transport model equations. Three mechanisms for the bipolar losses, i.e., the loss cone loss, collisional bulk viscosity loss of ions and the anomalous loss are simultaneously retained. Five-fold multiple bifurcations are found to exist at the plasma edge, similar to the previous 0-dimensional study. Double hysteresis causes a self-generated oscillation, which is attributed to the compound dither, a kind of ELMs. Spatio-temporal evolution of the compound dither is analyzed. (author)

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The Gateway to Astronaut Photography of Earth hosts the best and most complete online collection of astronaut photographs of the Earth.

International Nuclear Information System (INIS)

The use of europium as a local structural probe allows the various phases appearing in the NaCaPO_4-Na_3Eu(PO_4)_2 and NaSrPO_4-Na_3Eu(PO_4)_2 systems to be detected. The broadening of the europium emission lines in going from the calcium to the strontium phases illustrates the ease of displacement of the PO_4 groups. (Auth.).

International Nuclear Information System (INIS)

Three new phases with compositions, LaSr_2FeTiO_7, NdSr_2FeTiO_7 and GdSr_2FeTiO_7, were prepared by the traditional ceramic method. Lazy-Pulverix analysis of the X-ray diffraction data suggests that the phases crystallize in the RP-type (n = 2) structure in the space group, I4/mmm. The cell dimensions along the c-axis decrease with decrease in size of the rare earth ions. Electrical resistivity, as a function of temperature, shows that the materials are insulators and the resistivity decreases with decrease in the size of the rare earth ion, which is attributed to increase in the three-dimensional character. (author)

Energy Technology Data Exchange (ETDEWEB)

Porous SnO{sub 2} nanotubes were prepared via electrospinning followed by calcination in air. As anode materials for lithium ion batteries, the porous nanotubes delivered a high discharge capacity of 807 mAh g{sup -1} after 50 cycles. Even after cycled at high rates, the electrode still retained a high fraction of its theoretical capacity. Such excellent performances of porous SnO{sub 2} nanotubes could be attributed to the porous and hollow structure which facilitated liquid electrolyte diffusion into the bulk materials and buffered large volume changes during lithium ions insertion/extraction. Furthermore, the nanoparticles of nanotubes provided the shorter diffusion length for lithium ions insertion which benefited in retaining the structural stability and good rate performance. Our results demonstrated that this simple method could be extended for the synthesis of porous metal oxide nanotubes with ...

British Library Electronic Table of Contents (United Kingdom)

The algorithmic, or consistent, tangent stiffness was introduced to improve the asymptotic convergence rate of the iterative correction algorithm for the evolutive analysis of elastoplastic structures. The original approach is based on a formulation of the elastoplastic law in terms of a plastic multiplier with an analysis which, in general, requires an operator inversion. A geometric description of the method, based on hypersurface theory, is proposed here to provide a clear picture of the algorithmic properties. An estimate of the tangent stiffness associated with finite step elastoplastic and elastoviscoplastic constitutive models is given. It is based on the properties of the projection operator on the elastic domain and avoids operator inversions retaining the beneficial properties of...

British Library Electronic Table of Contents (United Kingdom)

In the present work, bulk amorphous and nanocrystalline Al83Fe17 alloys were obtained by consolidation of mechanically alloyed powders. Mechanical alloying of Al-17% Fe powder mixture yielded powder with an amorphous structure. Thermal behaviour of the milling product was examined using differential scanning calorimetry. This investigation revealed that the amorphous phase crystallised above 380^oC. The amorphous powder was compacted under a pressure of 7.7GPa in different conditions: at 380^oC for 600s and at 1000^oC for 180s. Structural investigations of the bulk material revealed that the amorphous structure was retained after consolidation process applied at 380^oC. Compaction under high pressure at 1000^oC caused crystallisation of the amorphous phase and appearance of metastable nano...

Energy Technology Data Exchange (ETDEWEB)

Improvements in critical current capacity for superconducting film structures are disclosed and include the use of a superconducting RE-BCO layer including a mixture of rare earth metals, e.g., yttrium and europium, where the ratio of yttrium to europium in the RE-BCO layer ranges from about 3 to 1 to from about 1.5 to 1.

International Nuclear Information System (INIS)

We present a study of the crystal field in PrNiAl, NdNiAl, ErNiAl and ErCuAl intermetallic compounds based on inelastic neutron spectroscopy. These compounds crystallize in the ZrNiAl-type hexagonal structure with an orthorhombic symmetry on rare-earth sites. The results are compared with the specific-heat data, and the lower parts of the crystal-field energy-level schemes are determined. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The crystal structure of borophosphates ABPO{sub 5} (A = alkaline earth or Pb) was resolved on a polycrystalline sample using the Rietveld method. The x-ray diffraction patterns data show that ABPO{sub 5} crystallize in a centrosymmetric space group P3{sub 1}21 and their structure is related to the borogermanates REBGeO{sub 5} with a stillwellite-type structure. Pr{sup 3+} ion was used as a local structural probe to corroborate the structural resolution results. Absorption and fluorescence spectra of A{sub 1-x}Pr{sub x}BP{sub 1-x}Ge{sub x}O{sub 5} (A alkaline earth or Pb; x = 0.05) have been investigated at different temperatures. At 9 K the 3{sup H}{sub 4}{yields}{sup 3}P{sub 0} transition of trivalent praseodymium ion (4f{sup 2} configuration) is observed as a single line. This indicates a unique crystallographic site for the rare ...

British Library Electronic Table of Contents (United Kingdom)

Photoluminescence properties and local electronic structures of rare earth (Eu^3^+ and Ce^3^+) activated Sr3AlO4F have been studied. X-ray powder diffraction data indicated that the activator ions of Eu^3^+ and Ce^3^+ can be incorporated into the Sr3AlO4F lattice and formed limited solid solutions of Sr3-2xLnxNaxAlO4F (Ln=Eu, Ce) with Na^+ as a charge compensator ion. The local structure around Sr sites was initially explored using Eu-activated Sr3AlO4F as a structural probe. Sr3AlO4F:Eu^3^+ exhibits orange-red emission ranging from 520 to 740nm with a maximum peak at about 619nm mainly originating from the ^5D0->^7FJ (J=0, 1, 2, 3, 4) transitions, indicating that Eu exists mainly in the trivalent state due to a strong oxidative lattice in Sr3AlO4F. Sr3AlO4F:Ce^3^+ shows an unusual long-wa...

Energy Technology Data Exchange (ETDEWEB)

Motivated by the discovery of superconductivity in alkali and alkaline earth fullerides, this program was undertaken both to understand the nature of and expand the range of materials demonstrating superconductivity. The first approach involved attempts to modify the fullerene cage by incorporating heteroatoms in the structure and the preparation and photophysical properties of nitrogen and sulfur doped fullerenes were studied in detail. The second approach involved examining the stoichiometry and effect of preparative conditions on the behavior of alkali, alkaline earth, lanthanide and mixed ion fullerides. In particular, the authors have elaborated on a technique for making such salts using liquid ammonia or aliphatic amines as solvents. Thirdly, modeling studies were undertaken to predict the properties of heterohedral fullerines and metal - C60 complexes, and theoretical guidelines were developed for understanding the ...

Energy Technology Data Exchange (ETDEWEB)

The use of europium as a local structural probe allows the various phases appearing in the NaCaPO/sub 4/-Na/sub 3/Eu(PO/sub 4/)/sub 2/ and NaSrPO/sub 4/-Na/sub 3/Eu(PO/sub 4/)/sub 2/ systems to be detected. The broadening of the europium emission lines in going from the calcium to the strontium phases illustrates the ease of displacement of the PO/sub 4/ groups.

International Nuclear Information System (INIS)

The influence of irradiation with 2.6 MeV H and He nuclei on the superconducting properties (critical temperature Tsub(c), critical current Isub(c)) of the intermetallic compound Nb_3Sn was studied. Irradiation led to a significant lowering of Tsub(c), while Isub(c) is increasing with the radiation dose. This is assumed to be due to the formation of active pinning centres in the lattice. There is a fast drop of Isub(c) after a peak value has been reached. Annealing of the samples (600-1,000"0C) led to an almost complete recovery of the initial value of Tsub(c). X-ray diffraction showed that irradiation causes considerable distortions of the lattice while the A15 crystal structure is retained. The causes of the radiation effects related to structural defects are discussed. (GSCH).

Energy Technology Data Exchange (ETDEWEB)

A model for the structural relaxation of grain boundaries (GBs) in nanostructured materials (NSMs) by diffusion-accommodated rigid body translations along GBs is proposed. The model is based on the results of recent computer simulations that have demonstrated that the GBs in NSMs retain a high-energy structure with random translational states due to severe geometrical constraints applied from neighboring grains (J. Appl. Phys. 78 (1995) 847; Scripta Metall. Mater. 33 (1995) 1245). The shear stresses within a GB caused by non-optimized rigid-body translations (RBTs) can be accommodated by diffusive flow of atoms along a GB. This mechanism is particularly important for low-angle and vicinal GBs, the energy of which noticeably depends on the rigid body translations. At moderate and high temperatures the model yields relaxation times that are very short and therefore GBs in NSMs can attain an equilibrium ...

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... wood, kitchen wastes, and human faeces with the ash from such burning deposited and retained in an ...

British Library Electronic Table of Contents (United Kingdom)

Metal iodates with a lone-pair containing I(V) that is in an asymmetric coordination geometry can form a diversity of unusual structures and many of them are promising new second homonic generation (SHG) materials. They exhibit wide transparency wavelength regions, large SHG coefficients and high optical-damage thresholds as well as moderately high thermal stability. In this paper, the structures and properties of the metal iodates are reviewed. The combination of d0 transition-metal cations with the iodate groups afforded a large number of metal iodates, with cations covering alkali metal, alkaline earth and lanthanide elements. Many of them are noncentrosymmetric (NCS) and display excellent SHG properties due to the additive effects of polarizations from both types of the asymmetric unit...

British Library Electronic Table of Contents (United Kingdom)

The crystal structure of Ca2RuD6 has been determined by neutron powder diffraction: space group Fm3m, K2PtCl6 structure, as found for other hexahydride salts of group 8 metals with alkaline earth or lanthanide counter ions. No structural phase transition was observed between 340K and 50K. The deuterium nuclear quadrupole coupling constant, 54.7kHz, leads to an ionic character of the Ru-D bond of 76%. The known trends in the behaviour of A2MH6 salts are interpreted in terms of the ionization energies of the cation and the central metal atom.

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A fusion reactor (such as NET/ITER) which breeds its own tritium fuel requires tritium recovery, purification and separation from the other isotopes. Cyclic adsorption processes are strong candidates for several of the processes involved: amongst other advantages, they promise a low tritium inventory. A good adsorbent for such processes must have high adsorption capacity, high selectivity and very low tritium retention after each cycle. Pure zeolite powder is shown to have an excellent combination of these three properties. However, in practice problems can arise from tritium which is not removed by reactivation. In this paper we show that tritium retention in zeolites can be caused either by water retained in the zeolite structure, which can be removed by ore rigorous activation, or by water tapped on binders in commercial pellets. (orig.).

International Nuclear Information System (INIS)

A biodegradable polylactic acid (PLA)/poly(glycolide-co-lactide) copolymer (PLGA) membrane with polyglycolic acid (PGA) mesh was prepared to aid the effective regeneration of defective periodontal tissues. The microporous membrane used in this study consists of biodegradable polymers, and seems to have a structure to provide appropriate properties for periodontal tissue regeneration. Based on the albumin permeation test, it is known that the biodegradable membrane exhibits the suitable permeability of nutrients. The membrane maintained its physical integrity for 6-8 weeks, which could be sufficient to retain space in the periodontal pocket. Cell attachment and cytotoxicity tests were performed with respect to the evaluation of biocompatibility of the membrane. As a result, the membrane did not show any cytotoxicity. The safety and therapeutic efficacies of the biodegradable membranes were confirmed in animal tests.

International Nuclear Information System (INIS)

It has recently been shown that the superconducting properties of Nb-base A-15 compounds, A_3B, are severely degraded when exposed to high-energy (E>1 MeV) neutron irradiation at ambient reactor temperatures. In each case, superconducting transition temperatures, Tsub(c), and the Bragg Williams order parameters, S, were observed to decrease steadily with irradiations in excess of 10"1"8 nvt. During irradiation the A-15 structure is retained and subsequent isothermal annealing restores almost completely the compound's original Tsub(c) value. In this letter a correlation between B atom diameter and the recovery rates of Tsub(c) for the irradiated materials Nb_3Ge, Nb_3Ga, Nb_3Al and Nb_3Sn is reported. (Auth.).

CERN Document Server

Strong gravitational lensing of an extended object is described by a mapping from source to image coordinates that is nonlinear and cannot generally be inverted analytically. Determining the structure of the source intensity distribution also requires a description of the blurring effect due to a point spread function. This initial study uses an iterative gravitational lens modeling scheme based on the semilinear method to determine the linear parameters (source intensity profile) of a strongly lensed system. Our 'matrix-free' approach avoids construction of the lens and blurring operators while retaining the least squares formulation of the problem. The parameters of an analytical lens model are found through nonlinear optimization by an advanced genetic algorithm (GA) and particle swarm optimizer (PSO). These global optimization routines are designed to explore the parameter space thoroughly, mapping model degeneracies in detail. We develop a ...

International Nuclear Information System (INIS)

Apparatus for solid-phase antibody separation techniques used in radioimmunoassays is described in this invention. It consists of a rectangular prism tray with multiple wells protruding into its interior from one side. Near the base of the tray is an orifice used for creating evacuated condition within the structure. At the base of each well there is an orifice of such size and shape as to retain an aqueous liquid under given pressure conditions but permit the evacuation of this liquid at reduced pressure. The outlet of these orifices is in the shape of an inverted conical frustrum. Each of the wells contains an antibody coated disc of porous cellulose paper surrounded by a plastic support. The porous nature of the cellulose paper ensures contact between the antibody coating and the antigen. The use of antibody coated porous cellulose paper in combination with the vacuum operated apparatus simplifies the manipulative steps whilst still ...

Energy Technology Data Exchange (ETDEWEB)

Magnetic properties of single crystals of nonstoichiometric fluorides M[sub 1-x]R[sub x]F[sub 2+x] (M = Ca, Sr, Ba; R = Ce, Pr, Nd, Gd, Ho, Er, Tm, Yb; with 0.05 [le] x [le] 0.28) with the fluorite-type structure have been studied for the first time. The magnetic susceptibility was measured using a Faraday balance in the 15-300 K temperature range. The samples are paramagnetic following the Curie-Weiss law. The values of paramagnetic Curie temperatures and effective magnetic moments of rare-earth ions have been found. Deviations of the temperature dependence of magnetic susceptibility from the Curie-Weiss law are observed for some nonstoichiometric fluorides at temperatures ranging from 60 to 85 K. Possible reaons for these deviations are discussed. Measurements of magnetic susceptibility provide an effective technique for a rapid and accurate determination of the concentration of rare-earth ions in nonstoichiometric ...

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New platinum(II) complexes with asymmetrically substituted chiral diamine ligands A{sub 2}PtX{sub 2}, (A{sub 2}=NH{sub 2}CH(CH{sub 3})CH{sub 2}NH(c-C{sub 5}H{sub 9}) (apcpa), NH{sub 2}CH(CH{sub 3})CH{sub 2}NH(c-C{sub 6}H{sub 11}) (apcha); X{sub 2}=2Cl, isopropylidenmalonate (IPM), 1,1'-cyclobutandicarboxylate (CBDCA) have been synthesized and characterized by means of elemental analyses, infrared and NMR spectroscopies, and X-ray crystallography. The crystal structures of (S-apcha)Pt[CBDCA]{center_dot}3H{sub 2}O (orthorhombic, P2{sub 1}2{sub 1}2(No. 18), a=6.926(3), b=15.243(3), c=19.319(4) A, V=2039.5(10) A{sup 3}, Z=4, R=0.072) and (S-apcha)Pt[IPM]{center_dot}2.5H{sub 2}O (monoclinic, P2/c(No. 13), a=9.882(1), b=18.502(1), c=22.056(1) A, V=4032.8(5) A{sup 3}, Z=8, R=0.093) exhibit that the platinum atoms achieve a typical square planar arrangement with two nitrogen atoms in cis position and with the chiral center retained. The ...

International Nuclear Information System (INIS)

Sialons are phases in the Si-Al-O-N and M-Si-Al-O-N systems where M includes Li, Mg, Ca, Sc, Y and the rare earth elements. They are comparable in variety with the mineral silicates and are built up of one-, two-, and three-dimensional arrangements of (Si,Al)(O,N)/sub 4/ tetrahedra in the same way that the structural units of the silicates are SiO/sub 4/ tetrahedra. These new materials include N-containing ceramics, glasses and glass-ceramics that are being explored for their thermal, chemical and physical properties.

British Library Electronic Table of Contents (United Kingdom)

The effects of a modifier that contains Rare Earths (RE), low melting point alloy (Al-Bi-Sb) and Ca-Si alloy on an ultrahigh carbon steel containing 1.9wt.% C were studied. Microstructure characterization was carried out with optical microscopy (OM) and scanning electronic microscopy (SEM) combined with energy-dispersive spectrometry (EDS). Upon modification, the continuous eutectic carbide network structure was broken up and changed to a partly isolated and finer blocky structure in the as-cast alloy. Differential scanning calorimetry (DSC) revealed that the eutectoid temperature increased and the eutectic temperature decreased for the modified alloy. Modification also improved the impact toughness of the tempered steel, with a significant increase from 6.5 to 12.6Jcm^-^2, despite the har...

International Nuclear Information System (INIS)

The US Army Engineers Waterways Experiment Station (WES) and US Army Engineer Division, Huntsville (HNDED) have developed general design criteria and specific design review criteria for the earth-mounded concrete bunker (EMCB) alternative method of low-level radioactive waste (LLW) disposal. An EMCB is generally described as a reinforced concrete vault placed below grade, underneath a tumulus, surrounded by filter-blanket and drainage zones. The tumulus is covered over with a low permeability cover layer and top soil with vegetation. Eight major review criteria categories have been developed ranging from the loads imposed on the EMCB structure through material quality and durability considerations. Specific design review criteria have been developed in detail for each of the eight major categories. 63 refs., 13 figs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

A preliminary design effort directed toward a low concentration ratio photovoltaic array system capable of delivering multihundred kilowatts (300 kW to 1000 kW range) in low earth orbit is described. The array system consists of two or more array modules each capable of delivering between 113 kW to 175 kW using silicon solar cells or gallium arsenide solar cells, respectively. The array module deployed area is 1320 square meters and consists of 4356 pyramidal concentrator elements. The module, when stowed in the Space Shuttle's payload bay, has a stowage volume of a cube with 3.24 meters on a side. The concentrator elements are sized for a geometric concentration ratio (GCR) of six with an aperture area of .25 sq. m. The structural analysis and design trades leading to the baseline design are discussed. It describes the configuration, as well as optical, thermal and electrical performance analyses that support the design and overall ...

International Nuclear Information System (INIS)

Ruthenium-106 administered to newborn rats and swine was incorporated into the epithelium of the lower small intestine and retained there for a few weeks after gavage; the stomach and small bowel of guinea pigs incorporated "1"0"6Ru but did not retain it.

International Nuclear Information System (INIS)

Biaxially textured tungsten nanorods (A15 crystal structure) have been grown by oblique angle DC magnetron sputtering using a novel rotation mode called 'two-step rotation'. In this mode, the substrate is given a fast rotation through 1800 at 90 rpm and this is followed by a rest period of 30 s. These nanorods are vertically aligned and have a [100] texture normal to the substrate along with preferential in-plane texture as shown by x-ray pole figure analysis. In contrast, the tungsten nanorods obtained without substrate rotation are slanted at an angle of ?450 and have a [100] texture tilted 160 with respect to the substrate normal. The flux is incident from two diametrically opposite points on the sample at an oblique angle, averaging out the growth into vertical columns that retain the in-plane texture. Scanning electron microscopy shows that the tungsten nanorods have a mixture of {211} and {421} crystal habits; these planes are both ...

Energy Technology Data Exchange (ETDEWEB)

CeO{sub 2} undergoes a first-order phase transition from fluorite to {alpha}-PbCl{sub 2}-type structure under high pressure. To evaluate the changes in physical properties of CeO{sub 2} nanomaterials as the particle size decreasing, high-pressure Raman study under quasi-hydrostatic condition has been performed on CeO{sub 2} nanospheres self-assembled by 5 nm CeO{sub 2} nanoparticles at room temperature. Surprisingly, as the pressure elevate to 34 GPa, the CeO{sub 2} nanospheres still retain the cubic fluorite-type structure, indicating the sample is more stable than the bulk counterpart. Whereas, previous high-pressure studies show the phase transition at 22.3/26.5 GPa for 12 nm CeO{sub 2} nanoparticles, which is less stable than the bulk materials. The enhancement of phase stability might be attributed to the increase of surface energy of CeO{sub 2} nanospheres as the size of the building units decrease. (Copyright ...

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Jun 8, 2006 ... It also reflects the large amount of deforestation that has occurred on the Haitian side of the border. One can easily see from satellite imagery ...

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Mar 30, 2007 ... Tropical forests are home to half the Earth's species, and their trees are an immense standing reservoir of carbon. Deforestation will have ...

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Jul 26, 2011 ... The Gateway to Astronaut Photography of Earth hosts the best and most complete online collection of astronaut photographs of the Earth.

Energy Technology Data Exchange (ETDEWEB)

The rare-earth based nickelates RNiO{sub 3} (R = Pr, Nd, Sm, Eu, and Pr{sub 1-x}La{sub x}, 0{<=}x{<=}0.7) were studied by inelastic neutron scattering. Energy splittings due to the crystalline-electric-field (CEF) interaction at the R{sup 3+} site within the electronic ground-state J multiplet (for R = Pr, Nd, and Pr{sub 1-x}La{sub x}) as well as within the two lowest-lying J multiplets (for R = Sm and Eu) were directly observed, and the corresponding CEF energy-level schemes were reconstructed. The latter were rationalized in terms of CEF parameters, which vary smoothly over the rare-earth series and give magnetic properties associated with the R sublattice in agreement with results from neutron powder diffraction experiments. Across the metal-insulator transition, a continuous change in the electronic part of the CEF parameters is observed. However, an attempt to quantify a charge transfer from the observed variation of the CEF ...

International Nuclear Information System (INIS)

The rare-earth based nickelates RNiO_3 (R=Pr, Nd, Sm, Eu, and Pr_1_-_xLa_x, 0#<=#x#<=#0.7) were studied by inelastic neutron scattering. Energy splittings due to the crystalline-electric-field (CEF) interaction at the R"3"+ site within the electronic ground-state J multiplet (for R=Pr, Nd, and Pr_1_-_xLa_x) as well as within the two lowest-lying J multiplets (for R=Sm and Eu) were directly observed, and the corresponding CEF energy-level schemes were reconstructed. The latter were rationalized in terms of CEF parameters, which vary smoothly over the rare-earth series and give magnetic properties associated with the R sublattice in agreement with results from neutron powder diffraction experiments. Across the metal-insulator transition, a continuous change in the electronic part of the CEF parameters is observed. However, an attempt to quantify a charge transfer from the observed variation of the CEF parameters in an effective point charge ...

Energy Technology Data Exchange (ETDEWEB)

In virtually all forms of life on earth, proteins in each cell are made according to a genetic blueprint, in the form of DNA. The translation of copies of this genetic blueprint (in the form of messenger RNA) into polypeptides is performed on the ribosome, a highly complex molecular machine composed of RNAs and proteins. To this end, special adaptor molecules called transfer RNAs are lined up by the ribosome in the sequence dictated by the genetic code, such that the amino acids carried by these molecules can be linked into a polypeptide. Several cofactors are involved in these processes, some of which require energy freed up by GTP hydrolysis. Although the ribosome was discovered more than 50 years ago, its structure has only been solved recently by X-ray crystallography. Another technique, cryo-electron microscopy, is starting to contribute toward our understanding of the ribosome's function, by portraying its conformational changes ...

International Nuclear Information System (INIS)

The spectroscopic properties of Pr"3"+ doping two lanthanum chlorotungstate hosts: the orthorhombic LaWO4Cl (1-1) and the hexagonal La3WO4Cl6 (3-1), as well as those of PrWO4Cl and Pr3wO613 have been investigated. The simulations of the energy level schemes are carried out within the crystal field theory frame. Each simulation involves 7 free ion parameters and 14 non-zero crystal field parameters (cfps), corresponding to the C_s point symmetry of the site occupied by the rare earth, in both structures.

International Nuclear Information System (INIS)

The magnetization of a series of intermetallic compounds Au_3R, where R is Gd through Yb, was investigated at 2.5 to 300"0K in applied fields up to 26 kOe. All the compounds studied exhibited the orthorhombic TiCu_3--Do/sub a/ type structure. For high temperatures, the temperature dependence of the inverse susceptibility followed a Curie--Weiss law, yielding effective paramagnetic moments in good agreement with the values calculated for free tripositive rare earth ions. At low temperatures, deviations from Curie--Weiss behavior were observed in all cases. These deviations are ascribed to the influence of crystal-field and exchange interactions. (auth).

Energy Technology Data Exchange (ETDEWEB)

The author presents a detailed and quantitative description of all of the programs, systems, sensors and experiments associated with the next 30 years of space endeavors by the National Aeronautics and Space Administration. Derived from the fifth issue of the NASA Space Systems Technology Model, the missions and payloads are categorized by applications area: solar system exploration, astrophysics, earth sciences, communications, space transportation and utilization of the space environment. Far-term missions are described as opportunity missions and landmark missions, for the distant future. Technology requirements are collected by discipline: power, propulsion, materials, structures, information systems, navigation, guidance and control. Payload technology requirements are organized by instrument sensing range. This information defines in quantitative terms, the opportunities and limits for future civilian space system capabilities.

International Nuclear Information System (INIS)

Three new rare earth metal-rich compounds, Gd_6MTe_2 (M=Co, Ni) and Er_6RuTe_2, were synthesized in direct reactions between the R, R_3M, and R_2Te_3 (R=Gd, Er, M=Co, Ni, Ru). These materials all adopt the same Zr_6CoAl_2 structure type with space group P6-bar 2m (No. 189, Z=1). Single crystal structures of Gd_6CoTe_2 and Er_6RuTe_2 were determined and lattice parameters are a=b=8.3799(5), c=3.9801(4) A, and a=b=8.1473(5) A, c=3.9962(4) A, respectively. Gd_6NiTe_2 was characterized by X-ray powder diffraction; lattice parameters are a=b=8.412(2), c=3.9577(9) A. Metal-metal bonding correlations were analyzed using the empirical Pauling bond order concept.

International Nuclear Information System (INIS)

We present first-time measurements of the Fermi surface and low-energy electronic structure of intermetallic compounds Gd_2PdSi_3 and Tb_2PdSi_3 by means of angle-resolved photoelectron spectroscopy (ARPES). We show that the Fermi surface in both compounds consists of an electron barrel at the #GAMMA# point surrounded by spindle-shaped electron pockets originating from the same band, with the band bottom of both features lying at 0.5 eV below the Fermi level. From the experimentally measured band structure, we estimate the momentum-dependent RKKY coupling strength and demonstrate that it is peaked at the 1/2#GAMMA# K wave vector. Comparison with neutron diffraction data from the same crystals shows perfect agreement of this vector with the propagation vector of the low-temperature in-plane magnetic order, thereby demonstrating the decisive role of the Fermi surface geometry in explaining the complex magnetically ordered ground state of ternary ...

International Nuclear Information System (INIS)

The umbrella magnetic structure of the terbium iron garnet (TbIG) has been studied using neutron diffraction experiments peformed in the 4.2 to 650 K temperature range which covers both the Neel temperature (Tsub(N) = 550 +- 10 K) and the compensation temperature (Tsub(comp) = 244 +- 2 K). When T > Tsub(N), the observed peak intensities originate from nuclear contribution only. When Tsub(comp) < T < Tsub(N), the results have been interpreted in the Neel theory of ferrimagnetism. Below Tsub(comp), three salient features have been observed: there appears superstructure lines forbiden by the cubic space group Ia3d, whereas the other superstructure peaks are found absent contrary to other heavy rare earth garnets; the strongest reflexion (110) vanishes near Tsub(comp). The magnetic modes associated to the rhombohedral symmetry space group R(-3)c have been calculated; the two inequivalent magnetic sites C_1 and C'_1 of the Tb"3"+ ion have ...

Energy Technology Data Exchange (ETDEWEB)

Flue gas desulfurizing capacities of active carbon fibers (ACF) made from polyacrylonitrile (PAN-ACF) were studied, the features were clarified and at the same time the factors governing the capacities were studied to get guides for better products. Desulfurization capacities of 17 kinds of ACFs were studied. Two kinds of PAN-ACF, FE-200 and FE-300, especially the latter exhibited the higher desulfurization capacity. The capacity of FE-300 was about 20 times higher than those of fibers other than PAN systems and about 4 times higher than that of active coke for desulfurization. From the influence of reacting conditions on the desulfurizating capacity and the desorption profiles of adsorbed SO {sub 2}, it was concluded that the capacity was determined by the effective adsorption capacity of ACF and SO {sub 2} was retained on ACF as sulfuric acid. It was suggested that main factors governing the adsorption capacity were the large surface area of ACF, the suitable ...

International Nuclear Information System (INIS)

The structure of a demountable vacuum joint designed for operation from -120 to +120 deg C is developed and tested. Requirements of especially low gas release from the materials used have been fulfilled; the same concerns low sealing efforts, repeated action and keeping tightness under loads, indium being used as a sealant. Experimental studies of demountable vacuum joints, dia 100,125,140,160,180 and 200 mm, with an indium sealant permit to make the following conclusions: 1. The joints are sealed at sealing specific efforts of 0.4 kg/mm (without considering atmospheric pressure). 2. The joints retain tightness at opening and closing a cover five times and under +-120 deg C. 3. To ensure repeated operation of the joint with continued stable sealing effort, one should make sure the sealed surfaces coincide at repeated sealing. 4. When operating demountable vaccum joints with indium sealant, one must take into account the time factor, since time ...

Science.gov (United States)

Description of how global warming could be disastrous for much of the earth's population....

ScienceCinema

...global warming situation is more than evaporation around ...background red ? which was the global warming the ...

International Nuclear Information System (INIS)

The rare earth metal rich compounds RE4NiMg (RE=Y, Pr-Nd, Sm, Gd-Tm, Lu) were synthesized from the elements in sealed tantalum tubes in an induction furnace. All compounds were investigated by X-ray diffraction on powders and single crystals: Gd4RhIn type, space group F4-bar 3m, Z=16, a=1367.6(2) pm for Y4NiMg, a=1403.7(3) pm for Pr4NiMg, a=1400.7(1) pm for Nd4NiMg, a=1386.5(2) pm for Sm4NiMg, a=1376.1(2) pm for Gd4NiMg, a=1362.1(1) pm for Tb4NiMg, a=1355.1(2) pm for Dy4NiMg, a=1355.2(1) pm for Ho4NiMg, a=1354.3(2) pm for Er4NiMg, a=1342.9(3) pm for Tm4NiMg, and a=1336.7(3) pm for Lu4NiMg. The nickel atoms have trigonal prismatic rare earth coordination. These NiRE6 prisms are condensed via common edges to a three-dimensional network which leaves voids for Mg4 tetrahedra and the RE1 atoms which show only weak coordination to the nickel atoms. The single crystal data indicate two kinds of solid solutions. The RE1 positions reveal small RE1/Mg ...

International Nuclear Information System (INIS)

Buffer layers with 100% lattice match with YBa2Cu3O7 - ? (YBCO) were prepared from mixed rare-earth-oxides applying a simple sol-gel process and dip-coating method. Structural analysis of the sol-gel derived powder by X-ray diffraction revealed that the mixing parameter, which eliminates the lattice mismatch with YBCO, is x = 0.2382, 0.1852, 0.1252, 0.0906, 0.0793 and 0.0395 in (Eu1 - xHox)2O3, (Eu1 - xErx)2O3, (Eu1 - xYbx)2O3, (Gd1 - xHox)2O3, (Gd1 - xYx)2O3 and (Gd1 - xYbx)2O3, respectively. Microstructural investigations were carried out for Gd1.819Ho0.181O3 films epitaxially grown on cube-textured Ni (100) substrates by sol-gel dip-coating process. X-ray diffraction of the buffer showed strong out-of-plane orientation on Ni tape. The (Gd1 - xHox)2O3 (222) pole figure indicated a single cube-on-cube textured structure. The omega and phi scans revealed good out-of-plane and in-plane alne alignments. The full-width at ...

Science.gov (United States)

Lumbar epidural anesthesia is useful in a variety of chronic benign pain syndromes, including lumbar radiculopathy, low back pain syndrome, spinal stenosis, and vertebral compression fractures. Given the increased number of epidural nerve blocks being performed, some have reported unexplained complications of a transient or permanent nature and with varying degrees of severity. However, no case has been reported of a broken epidural needle tip retained in the lumbar facet joint area. This represents the first reported case presentation of foraminal stenosis developing in a patient after a retained epidural needle tip. PMID:21286465

International Nuclear Information System (INIS)

Tremendous progress in the science of extrasolar planets has been achieved since the discovery of a Jupiter orbiting the nearby Sun-like star 51 Pegasi in 1995. Theoretical models have now reached enough maturity to predict the characteristic properties of these new worlds, mass, radius, atmospheric signatures, and can be confronted with available observations. We review our current knowledge of the physical properties of exoplanets, internal structure and composition, atmospheric signatures, including expected biosignatures for exo-Earth planets, evolution, and the impact of tidal interaction and stellar irradiation on these properties for the short-period planets. We discuss the most recent theoretical achievements in the field and the still pending questions. We critically analyze the different solutions suggested to explain abnormally large radii of a significant fraction of transiting exoplanets. Special attention is devoted to the ...

International Nuclear Information System (INIS)

The Yb"3"+-doped non-linear rare-earth calcium oxoborate crystals GdCa_4O (BO_3)_3 (GdCOB) and YCa_4O(BO_3)_3 (YCOB) were investigated by low-temperature absorption and selective excitation spectroscopy. The selective excitation and emission spectra revealed the spectral features of the main Yb"3"+ centre and the principal minority one in both crystals. The energy level schemes for these centres in both hosts, as well as structural assignments, were proposed. It was established that the minority centre, which represents about 10% of the total intensity and was assigned to Yb"3"+ in a Ca"2"+ site, is not a trap but an energy donor for the main centre. Common features of and differences between the vibronic structure of the two centres in GdCOB and YCOB are discussed. The existence of additional features in YCOB:Yb spectra is pointed out. (author)

Energy Technology Data Exchange (ETDEWEB)

DC resistivity, dc magnetization, and specific heat of eight Sc{sub 5}Co{sub 4}Ge{sub 10}-type crystal-structure compounds R{sub 5}T{sub 4}Ge{sub 10} for R = Dy, Ho, Er, Tm, and T = Rh and Ir are presented. The resistivity, single-crystal magnetization, and specific-heat results show that in all those compounds, the magnetic moments order antiferromagnetically in the c direction at low temperature. However, in the Er and Tm compounds, the magnetizations along x-y hard directions do not show any anomalies above 2.0 K. This suggests that the ordered Er and Tm ions, which have positive quadrupole coefficients, interact with a crystal field that has an electronic potential valley along the c axis. The fitting of the hard axis magnetizations to Curie-Weiss law suggests that the resulting antiferromagnetic-like {theta} reflects the strength of the crystal-field torque on the magnetic moments rather than the strength of antiferromagnetic exchange.

International Nuclear Information System (INIS)

Power plant components exposed to environments such as water and soil are susceptible to severe corrosion. Many times the effect of corrosion in power plant components can be catastrophic. The problem is aggravated for underground pipelines due to additional factors such as large network of pipelines, proximity to earth mat, high voltage transmission lines, corrosive chemicals, inadequate approach etc. Other components such as condenser water boxes, internals of pipelines, clarifier bridge structures, cooling water inlet gates and pipes etc. which are in continuous contact with water, are subjected to severe corrosion. The nature and locations of all such components are at places which are not accessible for routine maintenance and hence they require long term reliable protection against corrosion. Experience has shown that anti-corrosive coatings are inadequate in preventing corrosion and due to their location regular maintenance coatings are ...

International Nuclear Information System (INIS)

The projector augmented-wave (PAW) method was developed by Bloechl as a method to accurately and efficiently calculate the electronic structure of materials within the framework of density-functional theory. It contains the numerical advantages of pseudopotential calculations while retaining the physics of all-electron calculations, including the correct nodal behavior of the valence-electron wave functions and the ability to include upper core states in addition to valence states in the self-consistent iterations. It uses many of the same ideas developed by Vanderbilt in his open-quotes soft pseudopotentialclose quotes formalism and in earlier work by Bloechl in his open-quotes generalized separable potentials,close quotes and has been successfully demonstrated for several interesting materials. We have developed a version of the PAW formalism for general use in structural and dynamical studies of materials. In the present ...

Science.gov (United States)

The title compounds were prepared by arc-melting of the elemental components. Whereas NdPdSi and SmPdSi are already present after the arc-melting, alpha-GdPdSi and alpha-TbPdSi are formed only during the annealing at 800 degC. The four compounds crystallize with the recently reported alpha-YbAuGe type structure, which was refined for alpha-GdPdSi: Pnma, a=2108.0(4) pm, b=433.9(1) pm, c=745.6(1) pm, Z=12, R=0.026 for 1447 structure factors and 62 variable parameters. The lanthanoid atoms are situated between two-dimensionally infinite nets of condensed, puckered hexagons formed by alternating palladium and silicon atoms, with Pd-Si distances varying between 251 and 262 pm. In the third dimension these nets are linked via weak Pd-Pd (300 pm), Pd-Si (283 pm), and Si-Si bonds (261 pm). The refinements of the occupancy parameters suggested that ca. 2% of the palladium sites are occupied by silicon atoms and vice versa. The ...

Science.gov (United States)

of satellite, aircraft and ground-based observations. In ..... swarm traps by Utah Department of Food and Agriculture (DAF) personnel. Preliminary Results ..... the 150th anniversary of the book's publication and the 200th anniversary of Darwin's birth. ...... cold war submarine missions to find that Arctic Ocean ...

Energy Technology Data Exchange (ETDEWEB)

Rare Earth Cobalt (REC) permanent magnets have unique properties that permit solutions to some optical tasks that cannot be accomplished with conventional magnets. A review of design and of performance characteristics of these magnets includes an analytical description of the three dimensional fringe fields of REC quadrupoles.

Science.gov (United States)

(Like using solar cookers to make hot dogs! Yummm!) How many people do you want to attend? 5? 30? 200?!? (Ambitious aren't we?) ...

UK PubMed Central (United Kingdom)

We calculate the expected fluxes of cosmic ray nuclei with charge 5 ≤ Z ≤ 28 at various depths in the earth's atmosphere, taking into account the initial charge distribution,...Full Text Available

International Nuclear Information System (INIS)

The prospect for the recovery of rare earths from red mud, the bauxite tailings from the production of alumina is examined. The Jamaican red mud by far has the higher trace concentrations of lanthanum, cerium, neodymium, and yttrium. Scandium is also present. The dissolution of the rare earth is a major extraction problem because of the large volume of other materials. The recovery processes that have been proposed include the production of co-products such as iron, alumina, and titanium concentrates, with the rare earths going with the titanium. In this paper a critical examination of the possible processes are presented with the recommended research projects to be carried out.

National Aeronautics and Space Administration (NASA)

NASA's Glory spacecraft is equipped to survey and map aerosols in Earth's atmosphere during a mission marking the return to flight of the Taurus XL rocket.

Science.gov (United States)

Topics covered include: Methods of Helium Injection and Removal for Heat Transfer Augmentation; The

Science.gov (United States)

The aim for deterministic control of the interactions between macroions in aqueous media has motivated widespread experimental and theoretical work. Although it has been well established that like-charged macromolecules can aggregate under the influence of oppositely charged condensing agents, the specific conditions for the stability of such aggregates can only be determined empirically. We examine these conditions, which involve an interplay of electrostatic and osmotic effects, by using a well defined model system composed of F-actin, an anionic rod-like polyelectrolyte, and lysozyme, a cationic globular protein with a charge that can be genetically modified. The structure and stability of actin-lysozyme complexes for different lysozyme charge mutants and salt concentrations are examined by using synchrotron x-ray scattering and molecular dynamics simulations. We provide evidence that supports a structural transition from columnar ...

International Nuclear Information System (INIS)

The rare earth antimonates RE_3Sb_5O_1_2 constitute an isostructural series, where the rare earth site symmetry is S_4. The spectroscopic properties of pure or doped compounds of this family are studied in order to derive their energy level schemes and to simulate them through the crystal field theory, by using the approximated D_2_d potential. The paramagnetic susceptibilities are calculated with the derived wavefunctions and compared to experiment.

Energy Technology Data Exchange (ETDEWEB)

Some of the results of property measurements of CeO{sub 2} and its solid solutions were reviewed. The deviation from stoichiometry of undoped and doped CeO{sub 2} was presented in several figures, which suggested that CeO{sub 2} fired at high temperatures in air might be nonstoichiometric in some degree. At low temperatures, the deviation from stoichiometry in doped CeO{sub 2} is higher than undoped CeO{sub 2}. As another interesting property, CeO{sub 2} shows high solubility to trivalent cations such as rare earth elements. A possible reason behind this high solubility was presented. The nonstoichiometric defect in undoped CeO{sub 2} and the trivalent cation in solid solution with CeO{sub 2} have to be compensated by other defects. The possible defect structures in this solid solution were reviewed and the most probable structure was chosen based on density measurement and impurity dependence of oxygen diffusion ...

International Nuclear Information System (INIS)

Recent advances in thin film solar photovoltaic converters (PV's) can furnish multimegawatt power levels during lunar daylight periods with only modest mass requirements. The extended duration of lunar night (ca. 354 hr) and the high specific mass of earth-imported energy storage systems (regenerative fuel cells, batteries, etc.) render PV plus import storage power systems non-competitive with nuclear power plants for lunar bases. However, power storage or generation methods which can be constructed using primarily lunar materials, used either alone or with lightweight PV's, can be attractive alternatives to nuclear power. Three separate generic systems which can provide favorable low import mass goals have been identified and studied. These are: gravitational energy generation using lunar soil, thermal energy storage using basalt rock or glass, and electrochemical storage using lunar derived electrodes or fuels. Design, structural and ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Lithium-indium oxide is one of the candidate materials as solid-state scintillators for solar neutrinos due to an inverse --decay of 115In to 115Sn. On the other hand, when doped with rare-earth ions such as Eu3+ or Sm3+, it becomes a promising phosphor material. In this report we present a simple solid-state procedure for preparation of LiInO2:Eu3+ powders. X-ray diffraction confirmed prod-uct in tetragonal structural form (space group: I41/amd) and no impurity phases were detected. Then, high resolution photoluminescence emission measurements were performed at room and low temperatures to find 5D0 - 7FJ. Emission kinetics from 5D0 level exhibited pure single exponential behavior with lifetime of about 1.5 ms. Maximum energy splitting of 7F1 manifold is recorded as a function of ...

Energy Technology Data Exchange (ETDEWEB)

A concept is shown for a fully reusable, Earth-to-orbit launch vehicle with horizontal takeoff and landing, employing an air-turborocket for low speed and a rocket for high-speed acceleration, both using liquid hydrogen for fuel. The turborocket employs a modified liquid air cycle to supply the oxidizer. The rocket uses 90% pure liquid oxygen as its oxidizer that is collected from the atmosphere, separated, and stored during operation of the turborocket from about Mach 2 to 5 or 6. The takeoff weight and the thrust required at takeoff are markedly reduced by collecting the rocket oxidizer in-flight. This article shows an approach and the corresponding technology needs for using air liquefaction and enrichment system propulsion in a single-stage-to-orbit (SSTO) vehicle. Reducing the trajectory altitude at the end of collection reduces the wing area and increases payload. The use of state-of-the-art materials, such as graphite polyimide, in a direct substitution for ...

British Library Electronic Table of Contents (United Kingdom)

Radioactive rare earth chlorides in waste LiCl-KCl molten salts have to be separated as a stable form to minimize waste volume and to achieve stable solidification. In this work, thermal behavior of rare earth chlorides (CeCl3, GdCl3, NdCl3, PrCl3) was investigated in an oxygen condition to recover rare earth oxides from a LiCl-KCl-RECl3 system. The rare earth chlorides in the LiCl-KCl molten salts were smoothly converted to an oxychloride form at a higher temperature than 650degreeC, except for CeCl3. CeCl3 was totally converted to an oxide from at a higher temperature than 450degreeC. The rare earth oxychlorides (GdOCl, NdOCl, PrOCl) were effectively converted to oxide forms at a higher temperature than 1100degreeC. It was confirmed that rare earth oxides can be recovered from a LiCl-KCl...

CERN Document Server

Most of the presently identified exoplanets have masses similar to that of Jupiter and therefore are assumed to be gaseous objects. With the ever-increasing interest in discovering lower-mass planets, several of the so-called super-Earths (i.e., with masses in the interval 1 M_earth < M < 10 M_earth), which are predicted to be rocky, have already been found. Here we report the possible discovery of a planet around the M-type star GJ 436 with a minimum mass of 4.8+/-0.6 M_earth and a true mass of ~5 M_earth, which makes it the least massive planet around a main-sequence star found to date. In contrast with other discoveries, the planet is identified from its perturbations on an inner Neptune-mass transiting planet (GJ 436b), by pumping eccentricity and producing secular variations in the orbital inclination. Analysis of published radial velocity measurements indeed reveals a ...

International Nuclear Information System (INIS)

Y2Te4O11:Eu3+ and Y2Te5O13:Eu3+ single crystals in sub-millimeter scale were synthesized from the binary oxides (Y2O3, Eu2O3 and TeO2) using CsCl as fluxing agent. Crystallographic structures of the undoped yttrium oxotellurates(IV) Y2Te4O11 and Y2Te5O13 have been determined and refined from single-crystal X-ray diffraction data. In Y2Te4O11, a layered structure is present where the reticulated sheets consisting of edge-sharing [YO8]13- polyhedra are interconnected by the oxotellurate(IV) units, whereas in Y2Te5O13 only double chains of condensed yttrium-oxygen polyhedra with coordination numbers of 7 and 8 are left, now linked in two crystallographic directions by the oxotellurate(IV) entities. The Eu3+ luminescence spectra and the decay time from different energy levels of the doped compounds were investigated and all detected emission levels were identified. Luminescence properties of the Eu3+ cations have been interpreted in consideration ...

International Nuclear Information System (INIS)

A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120 g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120 g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6-5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2-5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and ...

Energy Technology Data Exchange (ETDEWEB)

The Large Hadron Collider (LHC), under construction at CERN, uses superconducting magnets operating at a temperature of 1.9 K to guide the circulating particles. A specific feature of the main magnets (dipoles and quadrupoles) is the two-in-one design with two magnetic channels in one common retaining structure. Indeed, the accelerator is made of two rings, mechanically linked, that have to be simultaneously aligned during the installation in the already existing LEP tunnel. The assembly tolerances of the LHC main magnets have been reconsidered to take into account the tight constraints on geometry. The dipoles are bent to follow closely the curvature of the circulating particles and to make a larger mechanical aperture available for the circulating particles. In order to minimise the geometrical errors the dipole assembly procedure is assisted by high precision survey measurements based on laser trackers. By this we hope to reduce to {+-} 1 mm ...

Energy Technology Data Exchange (ETDEWEB)

A method for the introduction of N-(/sup 3/H)acetyl groups into glycosaminoglycans is described. The procedure is based on (/sup 3/H)acetylation of N-unsubstituted hexosamine residues by treating the polysaccharides with (/sup 3/H)acetic anhydride. Preparations of heparin and heparin sulfate were found to contain significant numbers of N-unsubstituted hexosamine residues, as isolates. In contrast, such units could not be detected in chondroitin sulfate, dermatan sulfate, or hyaluronic acid. These polysaccharides were therefore subjected to partial N-deacetylation by reaction with hydrazine in the presence of hydrazine sulfate. After treatment with (/sup 3/H)acetic anhydride, the specific activities of the resulting labeled polysaccharide preparations ranged between 0.1 X 10/sup 6/ and 0.6 X 10/sup 6/ cpm /sup 3/H/..mu..g of uronic acid. The /sup 3/H-labeled polysaccharide preparations did not differ significantly from the corresponding unlabeled starting materials with regard to ...

International Nuclear Information System (INIS)

Purpose: To describe the technique of DE MDCT colonoscopy and to assess its feasibility. Materials and Methods: 8 patients were scanned with DSCT with a DE scan protocol and dose modulation software. Analysis was performed using dedicated DE software. Prone non-contrast images and DE supine images after contrast injection were obtained. Results: DE colonoscopic images were successfully obtained in 7 patients, but the FOV did not cover all colonic segments in 1 patient, thus resulting in a technical success rate was 87.5%. Streak artifacts were present in the pelvic region in 2 patients. Virtual unenhanced images and iodine map images were obtained for all patients. In 1 patient a polypoid non-enhancing structure was noted on the iodine map, and conventional colonoscopy revealed impacted stool. Enhancing rectal cancer in 1 patient was correctly shown on the iodine map. Iodine maps helped to differentiate stool fragments/retained fluid by the ...

UK PubMed Central (United Kingdom)

Peripartal serum alkaline phosphatase activity and lactate dehydrogenase activity were measured in 30 dairy cows in order to examine the association between retained fetal membranes and enzyme activity....Full Text Available

UK PubMed Central (United Kingdom)

After preparation on self-generated Percoll gradients, avocado (Persea americana Mill, var. Fuerte and Hass) mitochondria retain a high proportion of cyanide-insensitive respiration,...Full Text Available

UK PubMed Central (United Kingdom)

A stain of 0.1% toluidine blue in a 1.0% aqueous solution of triethylene glycol followed by decolorization with acid-alcohol resulted in mycobacteria retaining the stain (violet), whereas non-acid-fast...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Purpose - The purpose of the paper is to draw together the salient issues surrounding customer loyalty and customer relationship management (CRM) into a single coherent discussion. Various schools of academic thought are examined. The paper concludes with practical implications for managers. Design/methodology/approach - The literature surrounding customer loyalty, customer satisfaction, effective CRM and managing loyalty in a profitable manner are all reviewed. The paper allows managers to consider a wide range of material in the context of their business. Findings - The need for businesses to retain customers is an important issue in today's global marketplace. To retain customers, a business must forge loyal and long-term relationships with profitable customers. Reasons why customers le...

Energy Technology Data Exchange (ETDEWEB)

The invention concerns the conversion of steam turbines, particularly condensation turbines, for the economic coupling of process steam and heating steam. The conversion occurs by retaining the basic construction of foundations, housing and bearings as support group and coupling member and matching the specially developed construction for the idea of use into the existing housing, and inserting the rotor into the shaft unit. By having the unchanged supports of the housing and the bearings of the shaft unit, the elasticity in expansion and the vibration behaviour of the turbine are retained and the conversion costs can be lowered.

Energy Technology Data Exchange (ETDEWEB)

The instrument ball bearings are the key components of movable components for various kinds of measuring and control instruments; they often operate in the environmental condition of high-speed and light preload. In general, the non metal, disposable oilimpregnated retainer material has been used for these kinds of high precision miniature bearing. The engineering practice shows that the common failure mode of them is the wear which appears under the condition of insufficient lubrication condition. As the results, the vibration and noise will be enlarged, so does the frictional torque, which makes the ball bearings to lose its original working accuracy. It is the lifetime test of bearings that can enable the designers and manufacturers to chose the material of the bearing properly, optimize the product structure, mend the manufacturing technique process, and to enhance the technical level of the bearing products significantly. In this paper, ...

Energy Technology Data Exchange (ETDEWEB)

The rare earth antimonates RE{sub 3}Sb{sub 5}O{sub 12} constitute an isostructural series, where the rare earth site symmetry is S{sub 4}. The spectroscopic properties of pure or doped compounds of this family are studied in order to derive their energy level schemes and to simulate them through the crystal field theory, by using the approximated D{sub 2d} potential. The paramagnetic susceptibilities are calculated with the derived wavefunctions and compared to experiment.

International Nuclear Information System (INIS)

A series of Model Tests of Embedment Effect on Reactor Buildings has been carried out by the Nuclear Power Engineering Corporation (NUPEC), under the sponsorship of the Ministry of International Trade and Industry (MITI) of Japan. Seismic response of an embedded reactor building is greatly affected by the non-linearity of the backfill soil. However, quite few experimental data have been obtained so far. The objective of this study is to qualitatively evaluate the non-linear behavior of the backfill soil through shaking table tests. Its effects to the seismic response of a reactor building constructed at a soft rock site can be made clear through the tests. Non-linear effects of the backfill soil on the seismic response of the embedded reactor building model were evaluated experimentally. Based on the sinusoidal and seismic wave excitation tests, the following conclusions were obtained regarding the changes in vibrational characteristics of the building model which occurred according to ...

International Nuclear Information System (INIS)

Laser excited luminescence and site selective excitation spectra of trivalent terbium (Tb"3"+) in two rare earth oxyfluoride (ROF) matrices, LaOF and GdOF, were detected at temperatures down to liquid helium. From the analyses of spectra, the crystal field (c.f.) fine structure of the "7F_J (J=0-6) ground multiplet was obtained for the 4f"8 electron configuration. The energy level schemes comprising 26 c.f. sublevels out of 33 allowed for the C_3_v point symmetry of the R"3"+ site were simulated according to a phenomenological model taking into account only the c.f. effect. The simulation including six c.f. parameters (B_0"2, B_0"4, B_3"4, B_0"6, B_3"6, and B_6"6) reproduced the experimental energy level schemes in a satisfactory manner with rms deviations of 5 and 6 cm"-"1 for the LaOF and GdOF hosts, respectively. The c.f. parameter sets are characterized by B_0"2 values close to zero while the fourth and sixth rank parameters assumed rather ...

British Library Electronic Table of Contents (United Kingdom)

The gravitational torque applied on the Earth by the other celestial bodies generates periodic variations in the orientation of the Earth's rotation axis in space which are called nutations. Observations of Earth's nutations allow for insights into the physical properties of the inner core because of the presence of a normal mode, the Free Inner Core Nutation (FICN), which is characterized by a tilt of the inner core figure and rotation axes with respect to the mantle and outer core. The frequency of the FICN is controlled by the strength of the mechanical coupling acting at the inner core boundary (ICB) and by the ability of the inner core to deform under the action of centrifugal and gravitational forces. Attenuation of the FICN reflects energy dissipated by electromagnetic (EM) and visc...

Science.gov (United States)

Nov 8, 2010 ... Ihring Mission 11, the radiation dosimetry measurement system functioned normally and provided data on the Earth's trapped radiation belts ...

Energy Technology Data Exchange (ETDEWEB)

An oxidative precipitation reaction of rare-earth chlorides in a LiCl-KCl molten salt was successfully carried out by a lab-scale apparatus. The conversion efficiency of the used rare earth chlorides into the insoluble precipitates was increased with the sparging time and temperature and was affected on oxygen sparger type. In the conditions of 700 .deg. C molten salt temperature and above 540min sparging time, the final conversion efficiencies were over 99% for all the experimented rare-earth chlorides. The hydrodynamic characteristics of an oxygen-molten salt two phase flow system are very important for a co-oxidative precipitation of rare earth elements.

Science.gov (United States)

... Astronomy & Space Biology Chemistry & Materials Computing Earth & Environment Education ... Materials Research Center at the University of Chicago, one of nearly 30 NSF-supported Materials ...

Science.gov (United States)

The rapidly growing field of remote sensing is beginning to supply massive amounts of high resolution imagery of the earth and other planets. ...

Science.gov (United States)

Feb 15, 2010 ... This astronaut photo from January 4, 2010, shows meander scars and oxbow lakes in the floodplain of the Rio Negro in South America.

Science.gov (United States)

Federal regulators were set to vote on a plan to protect deep water corals and other sensitive fish habitats that will likely include a permanent ban on ...

British Library Electronic Table of Contents (United Kingdom)

This study presents new software, called Google Earth-based Optimal HAulage RouTing System (GEOHARTS), to improve the functionality of Google Earth for optimal haulage routing of off-road dump trucks in construction and mining sites. A modified least-cost path algorithm, which is applicable to working areas with both paved and unpaved temporary roads and can consider the effects of terrain relief and curves along a route on the route planning, was proposed and utilized for the software development. GEOHARTS can determine optimal haulage routes between loaders and dumps that ensure the least travel time or fuel consumption of off-road dump trucks and can visualize the results using an embedded 3D render window of Google Earth. The application to the Pasir open-pit coal mine in Indonesia dem...

Science.gov (United States)

Satellite Observations of the Southeast Pacific Intertropical Convergence Zone During 1993-1998, Halpern, D.; Hung, C.-W., Journal of Geophysical Research ? ...

Science.gov (United States)

... Zinn, J., Hoerlin, H., and Petschek, AG, "The Motion of Bomb Debris Follow- ing the Starfish Test," Radiation Trapped in the Earth's Magnetic Field ...

Science.gov (United States)

Hie synthesis of diverse biologically important compounds, under condi- tions which existed on the earth in the initial period of its evolution, ha; ...

CERN Document Server

The abstract is additional with repect to the paper published in JGCD. Ordinary Earth satellites are usually placed into five categories of special orbits: sun-synchronous orbits, orbits at the critical inclination, frozen orbits, repeating ground track orbits, and geostationary orbits. This paper investigates their counterparts around Mars and examines the basic nature of these orbits, which are of special interest for missions conducted around Mars, including Mars reconnaissance. Mars' gravity field is much more complicated, with relatively smaller J2, compared to Earth's, which makes the behaviors of these Martian orbits different from those of Earth. Analytical formulations and numerical simulations are used to analyze these Martian orbits and compare them with their Earth counterparts. First, mean element theory is employed to describe variations of orbital elements and give the constraint ...

Science.gov (United States)

Turbine Afterword The SHARP cannon. Hydrogen is compressed in the tube on top, the gun barrel is on bottom. When Jules Verne wrote in 1865 "From Earth to the Moon" he envisioned...

International Nuclear Information System (INIS)

... gamma cascades kev range 10-100 lifetime lutetium 171 lutetium 173 lutetium

Science.gov (United States)

Deforestation in Mato Grosso, Brazil. atom_author. atom_name, Jesse Allen. atom_link. kml_href, http://earthobservatory.nasa.gov/Feeds/GoogleEarth/ ...

British Library Electronic Table of Contents (United Kingdom)

World demand for rare-earth elements and the metal yttrium?which are crucial for novel electronic equipment and green-energy technologies?is increasing rapidly. Several types of seafloor sediment harbour high concentrations of these elements. However, seafloor sediments have not been regarded as a rare-earth element and yttrium resource, because data on the spatial distribution of these deposits are insufficient. Here, we report measurements of the elemental composition of over 2,000 seafloor sediments, sampled at depth intervals of around one metre, at 78 sites that cover a large part of the Pacific Ocean. We show that deep-sea mud contains high concentrations of rare-earth elements and yttrium at numerous sites throughout the eastern South and central North Pacific. We estimate that an a...

Science.gov (United States)

switch when this cavity matching condition is determined. This results is a ... MHz offset is provided by an acousto-optic modulator. (AOM). The AOM will be shut ...

CERN Document Server

In this paper, we first discuss the detection of supernova neutrino on Earth. Then we propose a possible method to acquire information about $\\theta_{13}$ smaller than $1.5^\\circ$ by detecting the ratio of the event numbers of different flavor supernova neutrinos. Such an sensitivity cannot yet be achieved by the Daya Bay reactor neutrino experiment.

International Nuclear Information System (INIS)

Molar extinction coefficients for the solid solutes in aqueous solutions of some alkaline earth chlorides such as MgCl_2.6H_2O, CaCl_2, SrCl_2.6H_2O and BaCl_2.2H_2O have been determined at 81, 356, 511, 662, 1173 and 1332 keV energies in different concentration using the narrow beam transmission methods. (author)

CERN Document Server

Among the billions of planetary systems that fill the Universe, we would like to know how ours fits in. Exoplanet data can already be used to address the question: How common are Jupiters? Here we discuss a simple analysis of recent exoplanet data indicating that Jupiter is a typical massive planet rather than an outlier. A more difficult question to address is: How common are Earths? However, much indirect evidence suggests that wet rocky planets are common.

Wastenet

...Observatory Edinburgh SkyView Virtual Observatory Solar System Simulator Space Telescope Science Institute Space Weather : A Research Perspective Subaru Telescope Project Two Micron All ...Universities for Research in Astronomy Subjects: space observation DeweyClass: 522 Resource type: index Space Weather : A Research Perspective Documents discussing space weather , the ...elements of near-Earth space, Earth-space meteorology and practical consequences of space weather . Glossary included. Author: National Academy of ...

Energy Technology Data Exchange (ETDEWEB)

When a bipolar HVDC transmission system is operating monopolar using the earth as a return path, it is often desired to divert the return current from the earth to the line from the unused pole. To do so requires either that the system be shut down temporarily or that a dc circuit breaker be used. This paper describes the development of such a new dc circuit breaker, and its application on the Pacific Intertie as a Metallic Return Transfer Breaker (MRTB).

International Nuclear Information System (INIS)

We investigate the evolution of Type Ib/c supernova (SN Ib/c) progenitors in close binary systems, using new evolutionary models that include the effects of rotation, with initial masses of 12-25 M_s_u_n for the primary components, and of single helium stars with initial masses of 2.8-20 M_s_u_n. We find that, despite the impact of tidal interaction on the rotation of primary stars, the amount of angular momentum retained in the core at the presupernova stage in different binary model sequences converges to a value similar to those found in previous single star models. This amount is large enough to produce millisecond pulsars, but too small to produce magnetars or long gamma-ray bursts. We employ the most up-to-date estimate for the Wolf-Rayet mass-loss rate, and its implications for SN Ib/c progenitors are discussed in detail. In terms of stellar structure, SN Ib/c progenitors in binary systems at solar metallicity are predicted to have a ...

CERN Document Server

The bright star 55 Cancri is known to host five planets, including a transiting super-Earth. The interferometric study presented here yields directly determined values for 55 Cnc's stellar astrophyiscal parameters: $R=0.943 \\pm 0.010 R_{\\odot}$, $T_{\\rm EFF} = 5196 \\pm 24$ K. We use isochrone fitting to determine 55 Cnc's age to be 10.2 $\\pm$ 2.5 Gyr, implying a stellar mass of $0.905 \\pm 0.015 M_{\\odot}$. Our analysis of the location and extent of the system's habitable zone (0.67--1.32 AU) shows that planet f ($M \\sin i = 0.155 M_{Jupiter}$) spends the majority of the duration of its elliptical orbit in the circumstellar habitable zone, where, with moderate greenhouse heating, it could harbor liquid water. Finally, our direct value for 55 Cancri's stellar radius allows for a model-independent calculation of the physical diameter of the transiting super-Earth 55 Cnc e ($\\sim 2.05 \\pm 0.15 R_{\\earth}$), which, ...

Energy Technology Data Exchange (ETDEWEB)

This report is the culmination of approximately three and one-half years of research on the design and demonstration of a mineral endowment appraisal system which has as its foundation a formalization of geological decisions within a probabilistic framework. Basically, the probabilistic decision structure of a geologist or team of geologists is captured in a system of computer programs which can be used by a geologist for the estimation of the magnitude of uranium endowment by providing information to this system about the states of earth processes and geologic conditions that pertain to that region being evaluated. Research performed under this contract had two main objectives: demonstration of the endowment appraisal system on the San Juan Basin of New Mexico; a comparison of estimates by the appraisal system with estimates made using other methodologies. The scope of this report is restricted to a demonstration of the appraisal system and ...

International Nuclear Information System (INIS)

The SIEN 2009 symposium organized by Romanian Nuclear Energy Association, AREN, in co-operation with Romanian Atomic Forum, ROMATOM, was primarily targeting the expert community involved in developing new nuclear power projects and implementing the National Nuclear Program. The symposium was also open as a discussion and information forum for scientists, engineers, technicians and students interested in scientific and technologic topics of Nuclear Power. It was structured in the following 6 sections: - Nuclear new builds and developments; - Operation, inspection and maintenance; - Increasing nuclear safety features; - Fuel cycle and decommissioning; - Public perception and confidence strengthening; - Environmental management. The symposium began with three plenary lectures dealing with: - Sustainable Nuclear Energy European Technology Platform; - Nuclear new-build; - Current issues of nuclear equipment standardization in Romania. A poster session of 5 presentations ...

Energy Technology Data Exchange (ETDEWEB)

Substitution of various rare earths R within the class of R2PdSi3 single crystals with hexagonal AlB2-type crystallographic structure reveals the systematic dependence of anisotropic magnetic properties governed by the interplay of crystal-electric field effects and magnetic two-ion interactions. Here we compare the floating zone (FZ) crystal growth with radiation heating of compounds with R = Tb, Tm, Pr, and Gd. The congruent melting behavior enabled moderate growth velocities of 3 to 5 mmh-1. The preferred growth directions are close to the basal plane of the hexagonal unit cell. The composition of the crystals, except of Tb2PdSi3, is slightly Pd-depleted with respect to the nominal composition 16.7 at.% Pd. Thin precipitates of RSi secondary phases were detected in the crystal matrix. Their phase fraction can be diminished by growth from Pd-rich melt compositions and annealing treatments. The compounds exhibit antiferromagnetic order below ...

Science.gov (United States)

We describe the development of a fully coupled climate model configuration where the Community Climate System Model (CCSM) has been coupled with the VERDE (Visualizing Energy Resources Dynamically on the Earth) analysis modules that compute the response of the electric grid to temperature drivers. The VERDE model includes datasets characterizing the 26,500 sub-stations and 6,000 power generation stations fuel mix, efficiency, service areas, and future performance and these have been geo-located on a 1.4 degree latitude by 1.4 degree longitude CCSM grid (T85). The total electric customers have been computed using conversions derived from economic structure and population data. The carbon emissions per customer and the power generation in megawatts electric (MWe) have also been placed on reconciled 1 km, 4 km and the T85 climate model grid. The CCSM temperature for the present and future have been extracted from the climate model output and ...

Energy Technology Data Exchange (ETDEWEB)

The durability of ball bearings, 32-mm- and 45-mm-bore, with a retainer or glass cloth-polytetrafluoroethylene (PTFE) laminate was tested under a high radial load at a speed of 20,000 rpm in LOX or LN2. The retainers were characterized as good self-lubricators because the abrasive glass-cloth fiber tips exposed on the retainer were chemicaly etched away with hydrofluoric acid (HF). During testing, the bearing-cartridge-acceleration was monitored to detect bearing damage. Testing in LOX for about 2.2 hr showed that excellent lubricating conditions were obtained for all bearings. Testing in LN2 for about 5.1 hr detected that the fatigue life of the bearing was about the same as the calculated B10 fatigue life. The HF chemical treatment resulted in a reacted fluoride-oxide material which remained in the etched part of the glass fiber. Several chemical products, particularly MgO, CaO, and CaCO3, enhanced adhesion of PTFE ...

British Library Electronic Table of Contents (United Kingdom)

Despite advances in polymer and drug technology, the underlying stent platform remains a key determinant of clinical outcome. A clear understanding of stent design and the differences between various stent platforms are of increasing importance for the interventional cardiologist. Reduction in stent strut thickness has been associated with improved stent deliverability, improved procedural outcome, and lower rates of subsequent restenosis. Newer-generation 316L-SS stent designs have enabled reduced strut thickness while retaining radial strength and minimizing recoil, but with significant loss of radiopacity, leading to reduced visibility. Cobalt chromium alloys have enabled a reduction in stent strut thickness to around 80?90 mm while retaining modest radiopacity, but due to higher elasti...

Energy Technology Data Exchange (ETDEWEB)

This paper describes the experimental results of long-life solid lubricated ball bearings tested under high-vacuum of 10 exp -4 Pa, high-temperature of 300 C, and high-speed (9000 rpm) conditions. For full ball-type bearings, the thin soft metals, either Ag or Pb, which were coated on the races and balls, appeared to have good torque properties. However, the durability of such bearings was less than 300 hours. The transfer films from the lamellar solid MoS2 and metal composite retainers improved the torque and wear properties. For ceramic, i.e., silicon nitride, balls used with steel rings, wear occurred on the inner rings. All ceramic bearings with composite retainers showed improved torque and wear properties. 18 refs.

Energy Technology Data Exchange (ETDEWEB)

A.C.R.O. (Association pour le Controle de la Radioactivite dans l'Ouest) is a French non governmental organisation that operates a laboratory for radioactivity analysis. It was created in 1986 as a response to people demands for information and reliable, independent testing. The organisation mainly carries out missions of information and training for its correspondents and more generally for a wide audience, particularly for people who worry about problems of environment, health, management of radioactive waste and emissions. Thanks to its structure, it enables citizens to involve themselves together with scientists so as to gain access to information that was hither to reserved to specialists. The organisation can vouchsafe its independence from the diversity of its members and volunteers, as well as from the diversity of its money resources. Besides its headquarters situated on the city of Caen area (Normandy), three branches situated in North Normandy, ...

British Library Electronic Table of Contents (United Kingdom)

The need for alternative energy increases steadily???especially due to the climate change and the limited availability of fossil fuels. Geothermal power uses the intrinsic heat which is stored in the accessible part of the Earth???s crust. Its importance among the renewable energy resources originates from the almost unlimited energy supply of the Earth and its independence from external influences such as seasonal or even daily climatic variability. Nevertheless, there are risks which have to be assessed. From a mathematical point of view there are four building blocks of the characterization of deep geothermal systems: seismic exploration, gravimetry, modeling transport processes, and modeling the stress field. In particular, local depletion poses a significant risk during the industrial...

International Nuclear Information System (INIS)

A study has been made of the colour reaction involved in the interaction or rare-earth elements with the reagent orthanyl K, the optimum conditions for the reaction being: pH=4.0-4.5 and lambda=660-670 nm. The ratio of components in the complex is Me:R=1:2. Consideration of the relative optical density values of the complex solutions as a function of the serial number of the rare-earth elements made it possible to recommend orthanyl K as a selective reagent for determining La, Ce, Pr and Nb in a mixture of Tu, Yb, Lu and Y oxides. The molar extinction coefficients, the sensitivity of the reaction and the concentration limits where Beer's law applies were calculated. Lanthanum was determined in a binary mixture with thulium and yttrium. (author).

British Library Electronic Table of Contents (United Kingdom)

Spacecraft studies of the three terrestrial planets with atmospheres have made it possible to make meaningful comparisons that shed light on their common origin and divergent evolutionary paths. Early in their histories, all three apparently had oceans and extensive volcanism; Mars and Earth, at least, had magnetic fields, and Earth, at least, had life. All three currently have climates determined by energy balance relationships involving carbon dioxide, water and aerosols, regulated by solar energy deposition, atmospheric and ocean circulation, composition, and cloud physics and chemistry. This paper addresses the extent to which current knowledge allows us to explain the observed state of each planet, its planetology, climatology and biology, within a common framework. Areas of ignorance...

International Nuclear Information System (INIS)

The crystal structure, electronic structure, and photoluminescence properties of EuxSi6-zAlz-xOz+xN8-z-x (x=0-0.1, 0xMySi6-zAlz-x-yOz+x+yN8-z-x-y (M=2Li, Mg, Ca, Sr, Ba) have been studied. Single-phase EuxSi6-zAlz-xOz+xN8-z-x can be obtained in very narrow ranges of x?0.06 (z=0.15) and z2+ ions can be incorporated into nitrogen-rich Si6-zAlzOzN8-z. The Eu2+ ion is found to occupy the 2b site in a hexagonal unit cell (P63/m) and directly connected by six adjacent nitrogen/oxygen atoms ranging 2.4850-2.5089 A. The calculated host band gaps by the relativistic DV-X? method are about 5.55 and 5.45 eV (without Eu2+ 4f5d levels) for x=0 and 0.013 in EuxSi6-zAlz-xOz+xN8-z-x (z=0.15), in which the top of the 5d orbitals overlap with the Si-3s3p and N-2p orbitals within the bottom of the conduction band of the host. EuxSi6-zAlz-xOz+xN8-z-x shows a strong green emission with a broad Eu2+ band centered at about 530 nm under UV to near-UV excitation range. ...

Science.gov (United States)

Wildlife Monitoring System Schematic .......................... 40 ...... sentinel species - healthy fish are placed in an environment of water (where they arc not .... The way ir! which data for the fnre mdor study groups will be gathered tor managciacilt ...... Earth Resources Aircraft Program (ERAP) Camera ...

Science.gov (United States)

In this activity, students create two- and three-dimensional maps by using a data grid of an imaginary section of Earth's surface. They are challenged to create six different maps of various surface features and answer questions about them.

Science.gov (United States)

Oct 2, 2007 ... The Payload combines some of the most sensitive particle sensors .... provide state-of-the-art measurements of incoming x-ray, ultraviolet, .... It will be launched into a low-Earth orbit on a Delta 7320 rocket in September 2004. ...

Science.gov (United States)

As the presence of humans in space expands in scope and duration, the quality of life in space as well as on Earth becomes pertinent. .... Military uses of space, such as the introduction of space-based laser or particle beam weapons, may have a major impact on the way people think and relate to .... AIAA Student Journal. ...

International Nuclear Information System (INIS)

Russian 1980. p. 81. USSR Blokh, Ya.L. Dorman, LI Yanke, VG Khamirzov,

Energy Technology Data Exchange (ETDEWEB)

A procedure was developed to monitor boundaries within which secondary mining operations can be applied. Principal techniques include instrument and operative-remote observations of earth shifts and aerial photography of displacements on the surface of the trough.

Science.gov (United States)

ISS022, E, 8269, CHILE, OPEN PIT MINING OPERATIONS E. OF SIERRA GORDA, ROADS, DRAINAGE, -22.9, -69.1, 20091209. ISS022, E, 8270, CHILE, OPEN PIT MINING ...

Science.gov (United States)

5 days ago... Sun sensors, 2 secondary Sun sensors, and an Earth sensor. ... This continued intermittently until the rocket burn, at which time ... with incoming asymptotic direction at an angle of -13.6 degrees from the lunar equator. ...

Energy Technology Data Exchange (ETDEWEB)

Absorption and emission measurements at liquid-helium temperature, liquid-nitrogen temperature and room temperature have been performed on tetragonal scheelite-type rare earth sodium double molybdates Na[sub 5]RE(MoO[sub 4])[sub 4] and on RE-doped Na[sub 5]Gd(MoO[sub 4])[sub 4] samples. The rare earth occupies one single crystallographic position with S[sub 4] as point symmetry. The spectra were analysed according to the crystal field theory. From the experimental data, nearly complete energy level schemes of the Pr[sup 3+] and Nd[sup 3+], on the 4f [sup 2] and 4f [sup 3] configurations were derived. Very good correlation was obtained between the experimental and simulated energy level schemes, first for the approximated D[sub 2d] and then for the true S[sub 4] symmetries. The crystal field parameters vary smoothly with the atomic number of the rare earth, when compared with those determined previously for Eu[sup 3+] in the ...

Science.gov (United States)

Apr 25, 2010... oil per day were leaking from an oil well in the Gulf of Mexico in late April, following an explosion at an offshore drilling rig on April 20, 2010. ...

UK PubMed Central (United Kingdom)

BackgroundNematoda diverged from other animals between 600–1,200 million years ago and has become one of the most diverse animal phyla on earth. Most nematodes are free-living...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundLake Tanganyika (LT) is the oldest of the African Rift Lakes and is one of the richest freshwater ecosystems on Earth, with high levels of faunal diversity and endemism....Full Text Available

Science.gov (United States)

Features: CHUQUICAMATA, LARGE OPEN PIT MINING OPERATIONS, ROADS, HILLS Center Point Latitude: -22.3 Center Point Longitude: -68.9 (Negative numbers indicate ...

UK PubMed Central (United Kingdom)

From the gross conservation laws of thermodynamics in a convecting material we derive a bound on the ratio of the rate of production of mechanical or magnetic energy to the rate of internal radioactive...Full Text Available

Science.gov (United States)

retrieve detailed aerosol and cloud particle size distribution and shape ...... but on rain types, and hydrometeor characteristics. ..... of ice streams, decreasing sea ice cover in the Arctic, poleward movement of forest cover, and ...

Science.gov (United States)

Sep 9, 2009... a French Ariane rocket successfully launched a new Earth-observing satellite ... The payload is a pair of identical sensors known as "high-resolution ... the resulting image) are activated simultaneously by incoming radiation; ...

Wastenet

... In recent years workers in this field have focused on nucleation by nano-porous materials . This was in part motivated by a theoretical study by Page and Sear (2006) who proposed a two step model for nucleation in pores which suggest that there is ...

National Aeronautics and Space Administration (NASA)

One tiny marine plant makes life on Earth possible: phytoplankton. These microscopic photosynthetic drifters form the basis of the marine food web, they regulate carbon in the atmosphere, and are responsible for half of the photosynthesis that takes place on this planet.

International Nuclear Information System (INIS)

The broad bands in the room-temperature excitation spectra of Sm"3"+-, Dy"3"+- and Tm"3"+-activated Ca-#alpha#-SiAlON phosphors are interpreted as the N"3"--to-rare earth charge transfer transition (CTT). From the energies of the charge transfer transitions and from the optical data presented for the Eu"2"+ ion, the location of the divalent rare earth ion energy levels relative to the valence and the conduction band of Ca-#alpha#-SiAlON is derived. The salient features of the energy-level diagram are shown to be practical in explaining the temperature-dependent variations of the Eu"2"+ and Yb"2"+ luminescence efficiency in Ca-#alpha#-SiAlON. A comparative study pertaining to the nature of the Yb"2"+ and Eu"2"+ ion luminescence in Ca-#alpha#-SiAlON and in SrSi_2O_2N_2 is presented. A tentative energy-level diagram of the trivalent rare earth ions in Ca-#alpha#-SiAlON is also constructed.

Science.gov (United States)

is approximately 327000 km from the Earth's center (58000 km from the Moon's ...... source (figure 7-4). NEXT developed funding requirements for those ...... Code SF 2. 2101 NASA Rd. 1. Houston, TX 77058. Phone: (281) 483-7224 ...

National Aeronautics and Space Administration (NASA)

Expedition 22 Commander Jeff Williams, aboard the International Space Station 220 miles above Earth, responds to questions posted on YouTube concerning the station's orientation, life in space and the recent butterfly experiment.

Science.gov (United States)

Aluminium is an abundant metal consisting about 8 per cent of the earth's crust. It has long been considered as essentially nontoxic and nonabsorbable from the gastrointestinal tract. More recent studies have, however, due to better analytical capabilitie...

Science.gov (United States)

blast should have passed the Earth? Like: Follow APOD on Facebook Tomorrow's picture: whirlpool dust < | Archive | Index | Search | Calendar | RSS | Education | About APOD |...

International Nuclear Information System (INIS)

The formation of #alpha#'-sialon using Li as a modifying cation was investigated. The effects of the Li content, firing temperatures and Si/Al ratios on #alpha#'- yield were studied. The results indicated that at lower sintering temperatures the stabilisation of #alpha#'-sialons was obtained but the high weight losses of Li at higher temperatures limited the stabilisation. Increased ''Al'' content in the compositions resulted in an increase in the stability of Li-#alpha#'-sialon at higher temperatures, by the formation of a liquid phase which retains Li in the system. (orig.).

International Nuclear Information System (INIS)

This paper describes a method for measuring oil consumption in compressors. The oil is labelled with Zn 65. The consumed radioactive oil is retained in an activated carbon filter and its activity is measured continuously with a plastic scintillator detector. Measuring the oil consumption at a given operating levels takes about 15 minutes. At an oil consumption rate of about 1 g/h the measurement errors are of the order of +- 5%. (orig.).

UK PubMed Central (United Kingdom)

Hamsters breathed, nose-only, for 13 weeks, 5 days/week, 6 hr/day, either man-made vitreous fiber (MMVF)10a, MMVF33, or long amosite asbestos at approximately 300 World Health Organization (WHO) fibers/cc...Full Text Available

International Nuclear Information System (INIS)

Uranyl nitrate ("2"3"3U) was retained mainly in lung, skeleton, pelt and kidney 60 days after inhalation exposure. The concentration in lung exceeded that in other tissues. Preliminary results with "2"3"2U indicate retention in lung similar to that of "2"3"3U, at total deposited mass levels of 0.1 #mu#g or less.

CERN Document Server

We show that tilting a model sandpile that has dynamic disorder leads to bistability and hysteresis at the angle of repose. Also the distribution of {\\it local slopes} shows an interesting dependence on the amount of tilt - weakly tilted sandpiles retain the quasi-continuous distributions of the steady state, while large tilt makes the distribution more discrete, with local slopes clustered round particular values. These observations are used to explain recent experimental results on avalanche shapes; we give a theoretical framework in terms of directed percolation.

British Library Electronic Table of Contents (United Kingdom)

This paper summarizes the establishment and current development of space activities in the Bolivarian Republic of Venezuela. Space activities in Venezuela are focused on the areas of telecommunications, Earth observation and research on the physical properties of the Earth, and have as a primary goal the satisfaction of social needs. Current development of space activities started in 1999 when the new National Constitution recognized the value of outer space as the common heritage of mankind, and the key role of science and technology in promoting human welfare. The Bolivarian Agency for Space Activities (ABAE) was created in 2007. Its legal framework recognizes three key elements that drive its policy: the participation of society, capacity building and human training, and international c...

Energy Technology Data Exchange (ETDEWEB)

When in resonance, Raman scattering exhibits strong enhancement ranging from four to six orders of magnitude. This physical phenomenon has been applied to remote sensing of the Earth`s atmosphere. With a 16 inch Cassegrain telescope and spectrometer/ CCD-detector system, 70-150 ppm-m of SO{sub 2} in the atmosphere has been detected at a distance of 0.5 kilometer. This system can be used to detect/monitor chemical effluence in the atmosphere by their unique Raman fingerprints. Experimental result together with detailed resonance Raman and atmospheric laser propagation effects will be discussed.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a process for preparing poly(aryl ether ketones) by nucleophilic displacement polymerization in the presence of at least one alkali metal base selected from potassium, rubidium or cesium, and fluoride ions, which comprises adding to the polymerization: (a) an effective amount of at least one metal salt selected from lithium, sodium, alkaline earth or lanthanide chloride, bromide, iodide, sulfate, alkyl or aryl carboxylate, cyanide, borate or phosphate to slow or stop advancement of molecular weight and (b) an end-capping agent.

International Nuclear Information System (INIS)

Protecting Earth and planets against the invasion of 'alien life forms' is not military science fiction, but it is the peaceful daily job of engineers and scientists of space agencies. 'Planetary Protection' is preventing microbial contamination of both the target planet and the Earth when sending robots on interplanetary space mission. It is important to preserve the 'natural' conditions of other planets and to not bring with robots 'earthly microbes' (forward contamination) when looking for 'spores of extra terrestrial life'. The Earth and its biosphere must be protected from potential extraterrestrial biological contamination when returning samples of other planets to the Earth (backward contamination). The NASA-Caltech Laboratory for Planetary Protection of Dr. Kasthuri Venkateswaran at the Jet Propulsion Laboratory (JPL) (California, USA) routinely monitors and characterizes ...

Energy Technology Data Exchange (ETDEWEB)

The use of global three-dimensional (3-D) models with satellite observations of CO2 in inverse modeling studies is an area of growing importance for understanding Earth s carbon cycle. Here we use the GEOS-Chem model (version 8-02-01) CO2 mode with multiple modifications in order to assess their impact on CO2 forward simulations. Modifications include CO2 surface emissions from shipping (0.19 PgC yr 1), 3-D spatially-distributed emissions from aviation (0.16 PgC yr 1), and 3-D chemical production of CO2 (1.05 PgC yr 1). Although CO2 chemical production from the oxidation of CO, CH4 and other carbon gases is recognized as an important contribution to global CO2, it is typically accounted for by conversion from its precursors at the surface rather than in the free troposphere. We base our model 3-D spatial distribution of CO2 chemical production on monthly-averaged loss rates of CO (a key precursor and intermediate in the oxidation of organic carbon) and apply an ...

International Nuclear Information System (INIS)

Based on results from recent studies of elemental dietary intake and organ or tissue content for adult Chinese men, quoted nationwide elemental concentrations in Chinese soil and newly published national average consumption of dietary foods, values of both transfer coefficients and discrimination factor (DF) for transfer from soil via the diet to both critical organs and the whole body have been calculated for important elements in radiation protection, including alkaline earths, alkali metals, rare earths and other related elements. These calculations have used both the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) model and the DF method. In the UNSCEAR model, the basic parameters used to describe the transport of radionuclides are the transfer coefficients P_i_j, which describe the relationship of concentrations or other amounts between compartment i and the following compartment j, whereas the DF is the ...

Energy Technology Data Exchange (ETDEWEB)

The tribo characteristics of self-lubricating 40-mm-bore ball bearings with a retainer of glass cloth-polytetrafluoroethylene (PTFE) laminate, which has elliptical pockets with a large pocket clearance, were tested under thrust loads at speeds up to 50,000 rpm, 2 million DN, in liquid hydrogen (LH2) and in liquid nitrogen (LN2). During testing, the bearing torque, outer-race temperature, and electric resistance between the inner and outer races were monitored to verify the formation and rupture of a PTFE transfer film. Testing showed that the bearings having the elliptical retainer pockets were superior to the conventional bearings with circular pockets. It was determined that, at the maximum inner race spinning velocity of about 5 m/s, a PTFE transfer film could sustain the maximum Hertz stress, up to about 2000 N/sq mm, in LH2, without severe film rupture resulting in bearing seizure. In LN2, the critical load capacity of PTFE transfer film ...

International Nuclear Information System (INIS)

Object: To control the average liquid level of each steam generator at a constant level irrespective of the flow rate of sodium thereby to decrease change in the retained amount of sodium and at the same time to improve the load response characteristic. Construction: A method for decreasing to as large an extent as possible a change in the amount of sodium retained in a steam generator due to change in the flow rate, which comprises the steps of detecting the main recirculating flow rate of liquid sodium by the use of a sodium flow rate detector, amplifying the detected flow rate signal depending upon the ratio between the flow rates respectively in a super-heater and a re-heater (distribution ratio), delivering the amplified signal to a function generator which generates a liquid level setting signal for maintaining the respective average liquid levels of the super-heater and the re-heater at constant levels irrespective of the flow rates, and ...

Energy Technology Data Exchange (ETDEWEB)

There exist certain systems which generate real-time data at high bandwidth, but do not necessarily require the long-term retention of that data in normal conditions. In some cases, the data may not actually be useful, and in others, there may be too much data to permanently retain in long-term storage whether it is useful or not. However, certain portions of the data may be identified as being vitally important from time to time, and must therefore be retained for further analysis or permanent storage without interrupting the ongoing collection of new data. We have developed a system, Mahanaxar, intended to address this problem. It provides quality of service guarantees for incoming real-time data streams and simultaneous access to already-recorded data on a best-effort basis utilizing any spare bandwidth. It has built in mechanisms for reliability and indexing, can scale upwards to meet increasing bandwidth requirements, and handles both ...

Energy Technology Data Exchange (ETDEWEB)

Single doses of lead (trace to 445 mg/kg) were administered per os to suckling and adult mice. Both groups exhibited dose-independent lead retention when doses of 4 to 445 mg/kg were administered. However, developmental differences in the fraction of initial dose (FID) retained were evident for all doses administered. A much larger FID was retained in both age groups following administration of carrier-free /sup 203/Pb. The results are consistent with a mechanism of gastrointestinal lead absorption comprising two or more processes. Developmental differences were also observed in organ lead concentration relative to whole body concentration for kidneys, skull and brain 6 days following lead administration. Lead retentions (relative to whole body retention) in brain and in bone were linearly related to dose of lead administered in both suckling and adult age groups. Though uptake of lead into brain and into femur was observed to be directly ...

Energy Technology Data Exchange (ETDEWEB)

The oxidation of Cr(III) hydroxides, mixed Fe(III)-Cr(III) hydroxides, and specimens of spinel phases NiCr2O4 and Fe(Cr,Fe)2O4 have been investigated in alkaline suspensions under the action of air and pure oxygen (1-3 atm). The rate of reaction increases with increasing alkali concentration, temperature, and oxygen pressure. Pu(IV) fixed on chromium hydroxides is not oxidized by oxygen under these conditions but is retained in the precipitate.

International Nuclear Information System (INIS)

SP-700, an emerging #beta#-rich #alpha#+#beta# titanium alloy, is designed to improve superplastic formability as well as mechanical properties over Ti-6Al-4V alloy. Owing to its fine microstructure and low #beta#-transus temperature, it is superplastic-formable at temperature below 1,073K (800 C) with low flow stress. Remarkable workability of this alloy is also retained in conventional Manufacturing processes. Another advantage of SP-700 is heat treatment response which includes deep hardenability and quick aging kinetics. Corrosion resistance and machinability are equivalent to or better than Ti-6Al-4V alloy.

Energy Technology Data Exchange (ETDEWEB)

Ammonia gas (NH{sub 3}) has been used as a nitrogen source for plasma source ion implantation processing of electroplated chromium. No evidence was found of increased hydrogen concentrations in the bulk material, implying that ammonia can be used without risking hydrogen embrittlement. The retained nitrogen dose of 2.1 {times} 10{sup 17} N-at/cm{sup 2} is sufficient to increase the surface hardness of electroplated Cr by 24% and decrease the wear rate by a factor of 4.

Energy Technology Data Exchange (ETDEWEB)

An insulated letter drop plate comprises a back plate having an opening for the mail having two hinges at its upper part to attach a cover to; a frame for retaining a first insulation around its perimeter and around the opening; and suitable insulation. This back plate is also provided with an upper curved extension to cover and conceal said hinges. A cover is provided with two complementary hinges to be articulated with the first hinges on the back plate, and with a frame around the perimeter for the retention of a second insulation. A wire joins the first and second hinges, and a coil spring on the wire keeps the cover normally closed.

Energy Technology Data Exchange (ETDEWEB)

Bunker Hill Co. v. Environmental Protection Agency (EPA) challenged EPA's right to make on-site inspections. A review of the arguments in three Circuit Court Cases shows that the inspection would be meaningless if the chemical company retained exclusive control over inspections and the generated information, but neither court held the company in contempt for refusing admission to inspectors. Industry's claim that on-site monitoring is unconstitutional and the compromises in lawsuits suggest a lack of compliance by both industry and EPA in monitoring regulations. Congress needs to rewrite less-ambiguous regulations. 59 references. (DCK)

International Nuclear Information System (INIS)

The adsorption properties of four samples of the #alpha#-modification of boron nitride (#alpha#-BN) were investigated by the gas-chromatographic method. According to the electron microscopy data, the #alpha#-BN particles possess the shape of thin plates. An #alpha#-BN sample prepared from magnesium polyboride, is the most uniform adsorbent. For a series of n-alkanes, benzene, and alkyl benzenes, by testing the #alpha#-BN samples one has obtained the retained volumes (Henry constants) and the values of the differential adsorption heat, which are close to those of the surface zero filling. These thermodynamic characteristics of adsorption have shown that the #alpha#-BN, line the graphitized thermal carbon black, is not a specific adsorbent.

CERN Document Server

We investigate the influence of lunar-like satellites on the infrared orbital light curves of Earth-analog extra-solar planets. Such light curves will be obtained by NASA's Terrestrial Planet Finder (TPF) and ESA's Darwin missions as a consequence of repeat observations to confirm the companion status of a putative planet. We use an energy balance model to calculate disk-averaged infrared (bolometric) fluxes from planet-satellite systems over a full orbital period (one year). The satellites are assumed to lack an atmosphere, have a low thermal inertia like that of the Moon and span a range of plausible radii. The planets are assumed to have thermal and orbital properties that mimic those of the Earth while their obliquities and orbital longitudes of inferior conjunction remain free parameters. Even if the gross thermal properties of the planet can be independently constrained (e.g. via spectroscopy or visible-wavelength detection of specular ...

Energy Technology Data Exchange (ETDEWEB)

Hard X-ray/gamma-ray spectrometers aboard two interplanetary spacecraft, Ulysses and Pioneer Venus Orbiter (PVO), and two near-Earth spacecraft, Yohkoh and Compton Gamma Ray Observatory (GRO/BATSE), are currently in operation. A unique set of circumstances have permitted the observation of the 15 November 1991 (2238 UT) flare by all the four instruments. This intense flare (GOES class X 1.5) was associated with the bright (3B) H-alpha flare located on the disk (S13, W19) in the active region 6919. At the time of the flare, the Ulysses and PVO spacecraft were located respectively 101[degree] and 52[degree] west of the Sun-Earth line. Thus the view angles for the PVO and Ulysses instruments were quite different from those of the near-Earth instruments on GRO and Yohkoh. The preliminary photon energy spectra observed by the four instruments at different times during the flare will be presented and their implications regarding ...

Energy Technology Data Exchange (ETDEWEB)

Since living things began their activities on the earth, the extermination of living things in large number on global scale occurred twice 230 million years ago (P-Tr boundary) and 65 million years ago (K-T boundary). As to the cause of exterminating living things in short period, there are volcano eruption theory, meteorite collision theory and so on, but still it is not decided. Therefore, as to the strata of P-Tr boundary in south-western part of China where it has been known the preservation of P-Tr strata is especially good, the existence of elements was measured by instrument neutron activation analysis and ICP-MS, and the state of change was examined. According to the results, the change occurred at the P-Tr boundary on the earth, and further, the possibility of meteorite collision by paying attention to Ir were examined. The samples, the neutron activation analysis, the ICP-MS and the results are reported. The distinction by strata and ...

International Nuclear Information System (INIS)

The collision of the Earth with extra-terrestrial ice-volatile bodies is proposed as a mechanism to produce rapid changes in the geologic record. These bodies would be analogs of the ice satellites found for the Jovian planets and suspected for comets and certain low density bodies in the Asteroid belt. Five generic end-members are postulated: (1) water ice; (2) dry ice: carbon-carbon dioxide rich, (3) oceanic (chloride) ice; (4) sulfur-rich ice; (5) ammonia hydrate-rich ice; and (6) clathrate: methane-rich ice. Due to the volatile nature of these bodies, evidence for their impact with the Earth would be subtle and probably best reflected geochemically or in the fossil record. Actual boloids impacting the Earth may have a variable composition, generally some admixture with water ice. However for discussion purposes, only the effects of a dominant component will be treated. The general geological effects of such collisions, ...

International Nuclear Information System (INIS)

The isotopic composition of Pd, Ag, Cd and Te has been measured by solid source mass spectrometry for four samples from reactor zones 2, 3-4, 5-6 and 7, and from four host rock samples external to the reactor zones from the Oklo mine site. The concentrations of these elements have also been determined in the eight samples using the stable isotope dilution technique. Cumulative fission yields have been derived from the reactor zone samples after correcting where necessary for the terrestrial component of the element concerned. It has been shown that fission-produced Pd and Te are retained almost in their entirety in the uraninite reactor zone samples, whereas a significant fraction of fission-produced Ag and Cd have migrated from the reactor zones. Fission product Cd is observed in the host rock samples, whereas no strong evidence of fission-produced Ag could be found. This the fission-produced Ag which has migrated from the reactor zones has not been ...

International Nuclear Information System (INIS)

Up to now the retention of radioactive material for nuclear facilities has been based on the maximum individual dose. The maximum individual dose can locally be lowered considerably by higher dissolution. In general, the collective doses are not lowered by this. In order to set up regulations concerning collective doses, the new recommmendations of the ICRP are very welcome. However, the costs of detriment and the period to be considered have not yet been defined. Therefore there are no fixed methods for carrying out a cost-benefit analysis. Furthermore, for nuclear technology the costs and the effectiveness of the retention of radioactive material for non-realized facilities can only be quoted roughly, which makes a cost-benefit analysis more difficult. A cost-benefit analysis for the retention of radioactive material in nuclear power plants with LWRs and reprocessing plants of the PUREX process has been carried out with best estimate data. The results show that the development of ...

Wastenet

The structure of the creative industries is changing 15

British Library Electronic Table of Contents (United Kingdom)

This work aims to contribute to the understanding of the influence of the ionospheric layer height (ILH) on the thin layer ionospheric model (TLIM) used to retrieve ionospheric information from the GNSS observations. Particular attention is paid to the errors caused on the estimation of the vertical total electron content (vTEC) and the GNSS satellites and receivers inter-frequency biases (IFB), by the use of an inappropriate ILH. The work relies upon numerical simulations performed with an empirical model of the Earth?s ionosphere: the model is used to create realistic but controlled ionospheric scenarios and the errors are evaluated after recovering those scenarios with the TLIM. The error assessment is performed in the Central and the northern part of the South American continents, a re...

Energy Technology Data Exchange (ETDEWEB)

This journal contains the following articles (1) The Grand Challenge of Thermonuclear Ignition--Commentary by Edward I. Moses; (2) Orchestrating the World's Most Powerful Laser--The computer control system for the National Ignition Facility will soon have about 1.4-million lines of code running on more than 750 computers; (3) A Randon Walk through Time and Space--Albert einstein's 1905 papers on Brownian motion, random fluctuations, and statistical mechanics are fundamental to many Livermore research projects; (4) The Search for Methane in Earth's Mantle--Scientists are discovering that Earth's mantle may have untapped reserves of methane; and (5) Testing the Physics of Nuclear Isomers--Results from a tri-laboratory project contradict claims of accelerated release of energy from the nuclear isomer hafnium-178.

British Library Electronic Table of Contents (United Kingdom)

A methodology for the determination of the rare earth elements in uranium oxides by ion microprobe has been set up on a Cameca ims-3f instrument. An uranium oxide reference material from a syn-metamorphic uranium deposit related to albitisation has also been developed for this type of analysis. Applications of the methodology are presented for a series of uranium oxides selected from some major uranium deposit types: from the world's highest grade unconformity-related uranium deposit from the Athabasca Basin (Saskatchewan, Canada; the Shea Creek and the McArthur River examples), a perigranitic vein-type deposit (Pen Ar Ran, Vendee, France) and a volcanic caldera-related deposit (Streltsovkoye, Transbaikalia, Russia). Each type of uranium deposit appears to have a specific REE signature. Al...

International Nuclear Information System (INIS)

Ions of rare earth elements (r.e.e.) have been found to form with benzilic acid and rhodamine B precipitates hardly soluble in water and extractable by toluene. The conditions of La and Pr determination by extraction-spectrophotometry method are studied. Relative square deviation does not exceed 0.027 and 0.034 respectively. The method can be used for determination of other cerium sub-group r.e.e. in their salts and cannot be employed for determination of lighter r.e.e. in the presence of heavier r.e.e., because the latter form low soluble precipitates capturing the r.e.e. situated in the beginninq of the r.e.e. series.

Science.gov (United States)

We propose two algorithms to provide a full preliminary orbit of an Earth-orbiting object with a number of observations lower than the classical methods, such as those by Laplace and Gauss. The first one is the Virtual debris algorithm, based upon the admissible region, that is the set of the unknown quantities corresponding to possible orbits for a given observation for objects in Earth orbit (as opposed to both interplanetary orbits and ballistic ones). A similar method has already been successfully used in recent years for the asteroidal case. The second algorithm uses the integrals of the geocentric 2-body motion, which must have the same values at the times of the different observations for a common orbit to exist. We also discuss how to account for the perturbations of the 2-body motion, e.g., the J 2 effect.

Energy Technology Data Exchange (ETDEWEB)

The Gravity Probe-B (GP-B) spacecraft, designed to test predictions of general relativity, will fly in the mid 1990s. It will carry four electrostatically suspended gyroscopes in a cryogenic environment and will have a drag-free control system to minimize disturbances on the gyroscopes. The Stanford Test of Equivalence Principle (STEP) spacecraft, to fly later, will carry a set of test masses under very similar conditions. The possibility of using differential measurements of the GP-B gyroscopes suspension forces and the STEP tests mass displacement readout to form single-axis gravity gradiometers is explored. It is shown that the noise in the suspension systems is sufficiently small in the relevant frequency range, and that enough information is collected to compensate for the spacecrafts' attitude motion. Finally, using Breakwell's flat-earth approximation, these experiments are compared to other geodesy experiments and predict the contribution ...