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1

BWR core melt progression phenomena: Experimental analyses.  

National Technical Information Service (NTIS)

In the BWR Core Melt in Progression Phenomena Program, experimental results concerning severe fuel damage and core melt progression in BWR core geometry are used to evaluate existing models of the governing phenomena. These include control blade eutectic ...

L. J. Ott

1992-01-01

2

Vaporization of core materials in postulated severe light water reactor accidents  

Microsoft Academic Search

The vaporization of core materials other than fission products during a postulated severe light water reactor accident is treated by chemical thermodynamics. The core materials considered were (a) the control rod materials, silver, cadmium, and indium; (b) the structural materials, iron, chromium, nickel, and manganese; (c) cladding material, zirconium and tin; and (d) the fuel, uranium oxide. Thermodynamic data employed

D. Cubicciotti; B. R. Sehgal

1984-01-01

3

Core-melt source reduction system  

DOEpatents

A core-melt source reduction system for ending the progression of a molten core during a core-melt accident and resulting in a stable solid cool matrix. The system includes alternating layers of a core debris absorbing material and a barrier material. The core debris absorbing material serves to react with and absorb the molten core such that containment overpressurization and/or failure does not occur. The barrier material slows the progression of the molten core debris through the system such that the molten core has sufficient time to react with the core absorbing material. The system includes a provision for cooling the glass/molten core mass after the reaction such that a stable solid cool matrix results. 4 figs.

Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

1995-04-25

4

Core-melt source reduction system  

DOEpatents

A core-melt source reduction system for ending the progression of a molten core during a core-melt accident and resulting in a stable solid cool matrix. The system includes alternating layers of a core debris absorbing material and a barrier material. The core debris absorbing material serves to react with and absorb the molten core such that containment overpressurization and/or failure does not occur. The barrier material slows the progression of the molten core debris through the system such that the molten core has sufficient time to react with the core absorbing material. The system includes a provision for cooling the glass/molten core mass after the reaction such that a stable solid cool matrix results.

Forsberg, Charles W. (Oak Ridge, TN); Beahm, Edward C. (Oak Ridge, TN); Parker, George W. (Concord, TN)

1995-01-01

5

Vaporization of core materials in postulated severe light water reactor accidents  

SciTech Connect

The vaporization of core materials other than fission products during a postulated severe light water reactor accident is treated by chemical thermodynamics. The core materials considered were (a) the control rod materials, silver, cadmium, and indium; (b) the structural materials, iron, chromium, nickel, and manganese; (c) cladding material, zirconium and tin; and (d) the fuel, uranium oxide. Thermodynamic data employed for the solid and gaseous elements and oxides were based on measurements, while the data for the gaseous hydroxides were generally based on estimates from literature. Thermodynamic criteria were derived to determine whether the metallic element or the solid oxide was the stable condensed phase for the accident environmental conditions. Equations for the partial pressures for all gaseous species were also derived. The relevant environmental conditions were provided by the pressurized water reactor and boiling water reactor heat-up thermal-hydraulic codes. The volatilities of the core materials were found to decrease roughly in the following order: cadmium, indium, tin, iron, silver, manganese, nickel, chromium, uranium, and zirconium. Cadmium and indium would provide the largest mass of core material that can be transported out of the core.

Cubicciotti, D.; Sehgal, B.R.

1984-11-01

6

Mobility of core melts during Earth's accretion  

NASA Astrophysics Data System (ADS)

We have equilibrated carbon-saturated Fe?Ni?Co?S melts in a San-Carlos olivine matrix between 1350 and 1570°C at 2 GPa, to measure the median dihedral angles of metallic core melts in a silicate mantle matrix as a function of temperature and sulfur fugacity. The angles increase from about 68° for the most oxidized monosulfide liquid solutions (metal-sulfur ratio ˜ 0.97), to ˜ 115° for the most reduced metal-rich melts ( M/S ˜ 100 ). Temperature effects are small. These angles preclude that metallic core melts could have segregated efficiently from a crystalline silicate mantle by grain boundary percolation. We suggest that core formation must have occurred from a magma ocean.

Ballhaus, Chris; Ellis, David J.

1996-09-01

7

MODELLING CORED WIRE INJECTION IN STEEL MELTS  

Microsoft Academic Search

Cored wire injection is an essential feature of liquid steel processing. An estimation of the time for melting of the wire sheath (casing) and the subsequent release of the filling material cannot be done without resorting to an elaborate mathematical model due to the complexity of the heat transfer from the bath to the wire. In particular, the formation of

Sarbendu Sanyal; Sanjay Chandra; Amreekh Singh; G G Roy

8

The Annular Core Research Reactor (ACRR) postulated limiting event initial and building source terms  

SciTech Connect

As part of the update of the Safety analysis Report (SAR) for the Annular Core Research Reactor (ACRR), operational limiting events under the category of inadvertent withdrawal of an experiment while at power or during a power pulse were determined to be the most limiting event(s) for this reactor. This report provides a summary of the assumptions, modeling, and results in evaluation of: Reactivity and thermal hydraulics analysis to determine the amount of fuel melt or fuel damage ratios; The reactor inventories following the limiting event; A literature review of post NUREG-0772 release fraction experiment results on severe fuel damages; Decontamination factors due to in-pool transport; and In-building transport modeling and building source term analysis.

Restrepo, L F

1992-08-01

9

BWR core melt progression phenomena: Experimental analyses  

SciTech Connect

In the BWR Core Melt in Progression Phenomena Program, experimental results concerning severe fuel damage and core melt progression in BWR core geometry are used to evaluate existing models of the governing phenomena. These include control blade eutectic liquefaction and the subsequent relocation and attack on the channel box structure; oxidation heating and hydrogen generation; Zircaloy melting and relocation; and the continuing oxidation of zirconium with metallic blockage formation. Integral data have been obtained from the BWR DF-4 experiment in the ACRR and from BWR tests in the German CORA exreactor fuel-damage test facility. Additional integral data will be obtained from new CORA BWR test, the full-length FLHT-6 BWR test in the NRU test reactor, and the new program of exreactor experiments at Sandia National Laboratories (SNL) on metallic melt relocation and blockage formation. an essential part of this activity is interpretation and use of the results of the BWR tests. The Oak Ridge National Laboratory (ORNL) has developed experiment-specific models for analysis of the BWR experiments; to date, these models have permitted far more precise analyses of the conditions in these experiments than has previously been available. These analyses have provided a basis for more accurate interpretation of the phenomena that the experiments are intended to investigate. The results of posttest analyses of BWR experiments are discussed and significant findings from these analyses are explained. The ORNL control blade/canister models with materials interaction, relocation and blockage models are currently being implemented in SCDAP/RELAP5 as an optional structural component.

Ott, L.J.

1992-01-01

10

BWR core melt progression phenomena: Experimental analyses  

SciTech Connect

In the BWR Core Melt in Progression Phenomena Program, experimental results concerning severe fuel damage and core melt progression in BWR core geometry are used to evaluate existing models of the governing phenomena. These include control blade eutectic liquefaction and the subsequent relocation and attack on the channel box structure; oxidation heating and hydrogen generation; Zircaloy melting and relocation; and the continuing oxidation of zirconium with metallic blockage formation. Integral data have been obtained from the BWR DF-4 experiment in the ACRR and from BWR tests in the German CORA exreactor fuel-damage test facility. Additional integral data will be obtained from new CORA BWR test, the full-length FLHT-6 BWR test in the NRU test reactor, and the new program of exreactor experiments at Sandia National Laboratories (SNL) on metallic melt relocation and blockage formation. an essential part of this activity is interpretation and use of the results of the BWR tests. The Oak Ridge National Laboratory (ORNL) has developed experiment-specific models for analysis of the BWR experiments; to date, these models have permitted far more precise analyses of the conditions in these experiments than has previously been available. These analyses have provided a basis for more accurate interpretation of the phenomena that the experiments are intended to investigate. The results of posttest analyses of BWR experiments are discussed and significant findings from these analyses are explained. The ORNL control blade/canister models with materials interaction, relocation and blockage models are currently being implemented in SCDAP/RELAP5 as an optional structural component.

Ott, L.J.

1992-06-01

11

Isotope thermometry in melt-affected ice cores  

Microsoft Academic Search

Summertime melt at ice core sites can lead to enrichment of isotopic valuesIsotopic enrichment results in overestimation of ice core-derived temperaturesCorrection of isotopic enrichment improves temperature estimates

T. Moran; S. J. Marshall; M. J. Sharp

2011-01-01

12

The Annular Core Research Reactor (ACRR) postulated limiting event initial and building source terms  

Microsoft Academic Search

As part of the update of the Safety analysis Report (SAR) for the Annular Core Research Reactor (ACRR), operational limiting events under the category of inadvertent withdrawal of an experiment while at power or during a power pulse were determined to be the most limiting event(s) for this reactor. This report provides a summary of the assumptions, modeling, and results

Restrepo

1992-01-01

13

Isotope thermometry in melt-affected ice cores  

Microsoft Academic Search

A statistically significant relationship is observed between stable water isotopes (delta18O) and melt amounts in a melt-affected firn core (SSummit) taken from the Prince of Wales Icefield, Ellesmere Island, Canada. By contrast, a low-melt firn core taken from a higher-elevation, higher-latitude location on the same icefield shows no relationship between these variables. We interpret this as evidence for meltwater-induced isotopic

T. Moran; S. J. Marshall; M. J. Sharp

2011-01-01

14

Study of fission product loaded aerosols from core melting experiments  

NASA Astrophysics Data System (ADS)

A severe nuclear reactor accident may result in the meltdown of the reactor core. The formation of the core melt is accompanied by the appearance of aerosols consisting of vaporized and recondensed core constituents. The investigation of aerosol samples, which were generated in a laboratory scale core melting experiment and collected during a temperature range Of 1200-1900°C of the melting charge, was performed using X-ray Photoelectron Spectroscopy (XPS) and revealed silver, cadmium, indium, tellurium, iodine and cesium as constituents of the aerosol surface. The metal components were present as either oxides or hydroxides with the exception of silver, which remained in its metallic state.

Moers, H.; Dillard, J. G.; Klewe-Nebenius, H.; Kirch, G.; Pfennig, G.; Ache, H. J.

15

Separation of melting and environmental signals in an ice core with seasonal melt  

Microsoft Academic Search

We examine the impact of melt water percolation on the soluble ion chemical record from the Lomonosovfonna ice core. Principle component analysis shows that melting produces only simple changes between bubbly and clear ice facies, due to elution of ions. The data can be naturally split into four groups: pre-industrial, immediately before, and after the end of the Little Ice

John C. Moore; Aslak Grinsted; Teija Kekonen; Veijo Pohjola

2005-01-01

16

Ion fractionation and percolation in ice cores with seasonal melting  

Microsoft Academic Search

We examine the impact that post- depositional change has on ion concentrations in ice cores that suffer limited seasonal melting. We show that the impact in the case of at least one Svalbard ice core is limited to decreasing resolution of signals to about 3 years - a similar accuracy as the best dating can usually provide. We model various

John C. Moore; Aslak Grinsted

17

Core melt experiment series in LOFT  

SciTech Connect

LOFT is being considered for future experiments involving core decomposition and migration because of the renewed NRC interest in Class 9 accidents following the TMI-2 event and because LOFT has unique capabilities for conducting this type experiment. A set of fuel damage experiments designated L8, L12 and L17 have evolved from the preliminary planning as follows: L8 allows center fuel bundle damage to occur within the removal capabilities of the existing fuel removal equipment; L12 allows entire core damage and decomposition to occur within the core boundaries; and L17 allows the decomposed core to migrate and erode the core support structures, reactor vessel, containment structure and containment substratum.

Russell, M.L.

1980-01-01

18

The Core Melt Stabilization Concept of the EPR and its Experimental Validation  

SciTech Connect

The strategy of the European Pressurized Water Reactor (EPR) to avoid severe accident conditions is based on the improved defense-in-depth approaches of the French 'N4' and the German 'Konvoi' plants. In addition, the EPR takes measures, at the design stage, to drastically limit the consequences of a postulated core-melt accident. The latter requires a strengthening of the confinement function and a significant reduction of the risk of short- and long-term containment failure. Scenarios with potentially high mechanical loads and large early releases like: high-pressure RPV failure, global hydrogen detonation, and energetic steam explosion must be prevented. The remaining low-pressure sequences are mitigated by dedicated measures that include hydrogen recombination, sustained heat removal out of the containment, and the stabilization of the molten core in an ex-vessel core catcher located in a compartment lateral to the pit. The spatial separation protects the core catcher from loads during RPV failure and, vice versa, eliminates concerns related with its unintended flooding during power operation. To make the relocation of the melt into the core catcher scenario-independent and robust against the uncertainties associated with in-vessel molten pool formation and RPV failure, the corium is temporarily retained, accumulated and conditioned in the pit during interaction with a sacrificial concrete layer. Spreading of the accumulated molten pool is initiated by penetrating a concrete plug in the bottom. The increase in surface-to-volume ratio achieved by the spreading process strongly enhances quenching and cool-down of the melt after flooding. The required water is passively drained from the IRWST. After availability of the containment heat removal system the steam from the boiling pool is re-condensed by sprays. The CHRS can also optionally cool the core catcher directly, which, in consequence, establishes a sub-cooled pool near-atmospheric pressure levels in the containment. The described concept rests on a large experimental knowledge base which covers all main phenomena involved, including melt interaction with structural material, melt spreading, melt and quenching, as well as the efficacy of the core catcher cooling. Besides giving an overview of the EPR core melt mitigation concept, the paper summarizes its R and D bases and describes which conclusions have been drawn from the various experimental projects and how these conclusions are used in the validation of the EPR concept. (author)

Fischer, Manfred [AREVA ANP GmbH (Germany)

2006-07-01

19

Isotope thermometry in melt-affected ice cores  

NASA Astrophysics Data System (ADS)

A statistically significant relationship is observed between stable water isotopes (?18O) and melt amounts in a melt-affected firn core (SSummit) taken from the Prince of Wales Icefield, Ellesmere Island, Canada. By contrast, a low-melt firn core taken from a higher-elevation, higher-latitude location on the same icefield shows no relationship between these variables. We interpret this as evidence for meltwater-induced isotopic enrichment at SSummit. A percent melt-based correction slope is applied to isotopic values from SSummit. Uncorrected and corrected temperature records derived from the raw and corrected ?18O values are compared to bias-corrected temperature data from the NCEP Reanalysis. Improvements are observed in the isotopic reconstruction of SSummit annual precipitation-weighted temperatures when we correct for meltwater enrichment, with a reduction from +0.6°C to 0.0°C in the mean annual error and a decrease in root-mean-square error from 1.8°C to 1.6°C. The correction factor appears to overcorrect isotopic modification during high melt years such as 1999, during which SSummit experienced nearly 70% more melt than the average from 1975 to 2000. Excluding 1999 data from the correction analysis results in a slight reduction in mean absolute error from 1.4°C to 1.3°C. These results suggest that melt-induced isotopic modification cannot be corrected in very high melt years.

Moran, T.; Marshall, S. J.; Sharp, M. J.

2011-06-01

20

Inner core freezing and melting: Constraints from seismic body waves  

NASA Astrophysics Data System (ADS)

Hypotheses for the mechanisms of growth of Earth's inner core can be tested from observations of lateral variations of elastic and anelastic properties near the inner core boundary. Differential travel times of PKIKP-PKiKP and the apparent travel time of P waves diffracted around the inner core are consistent with the existence of a stably stratified, globally uniform, region of reduced velocity gradient at the bottom of the outer core. This layer may be a zone of iron enrichment relative to the bulk of the outer core, representing a zone either of crystallization or melting of the inner core. Weak backscattered PKiKP in the equatorial eastern hemisphere can be made consistent with either a hypothesis of freezing or melting. In a melting hypothesis, the eastern hemisphere is texturally older and smoother, with larger crystals or smaller elastic contrasts across grain boundaries providing weaker backscatter to the coda of PKiKP. Additional observations consistent with higher homologous temperature and melting in this region are the existence of a thin low velocity layer in the uppermost inner core inferred from multipathing of PKIKP + PKiKP waves and a bright spot in the amplitude of PKIIKP waves observed at antipodal distances. Alternatively, a freezing hypothesis in the eastern hemisphere is an inner core that is growing radially outward with crystals stretched in the vertical direction. This hypothesis can simultaneously explain weak backscattered PKiKP coda and high attenuation of transmitted PKIKP from the loss of backscattered energy at angles perpendicular to vertically oriented crystals. Strong backscattering observed in the coda of PKiKP sampling the equatorial western hemisphere of the inner core agrees best with a heterogeneity having an isotropic distribution of scale lengths in the uppermost inner core.

Cormier, Vernon F.; Attanayake, Januka; He, Kuang

2011-10-01

21

Core melt/coolant interactions: modelling. [PWR; BWR  

SciTech Connect

If there is not adequate cooling water in the core of a light-water reactor (LWR), the fission product decay heat would eventually cause the reactor fuel and cladding to melt. This could lead to slumping of the molten core materials into the lower plenum of the reactor vessel, possibly followed by failure of the vessel wall and pouring of the molten materials into the reactor cavity. When the molten core materials enter either region, there is a strong possibility of molten core contacting water. This paper focuses on analysis of recent FITS experiments, mechanistic and probabilistic model development, and the application of these models to reactor considerations.

Berman, M.; McGlaun, J.M.; Corradini, M.L.

1983-01-01

22

Core melt experiment series in LOFT  

Microsoft Academic Search

LOFT is being considered for future experiments involving core decomposition and migration because of the renewed NRC interest in Class 9 accidents following the TMI-2 event and because LOFT has unique capabilities for conducting this type experiment. A set of fuel damage experiments designated L8, L12 and L17 have evolved from the preliminary planning as follows: L8 allows center fuel

1980-01-01

23

Melting of subducted basalt at the core-mantle boundary.  

PubMed

The geological materials in Earth's lowermost mantle control the characteristics and interpretation of seismic ultra-low velocity zones at the base of the core-mantle boundary. Partial melting of the bulk lower mantle is often advocated as the cause, but this does not explain the nonubiquitous character of these regional seismic features. We explored the melting properties of mid-oceanic ridge basalt (MORB), which can reach the lowermost mantle after subduction of oceanic crust. At a pressure representative of the core-mantle boundary (135 gigapascals), the onset of melting occurs at ~3800 kelvin, which is ~350 kelvin below the mantle solidus. The SiO2-rich liquid generated either remains trapped in the MORB material or solidifies after reacting with the surrounding MgO-rich mantle, remixing subducted MORB with the lowermost mantle. PMID:24855266

Andrault, Denis; Pesce, Giacomo; Bouhifd, Mohamed Ali; Bolfan-Casanova, Nathalie; Hénot, Jean-Marc; Mezouar, Mohamed

2014-05-23

24

Melting properties of iron alloys under Earth's core conditions (Invited)  

NASA Astrophysics Data System (ADS)

The liquid core of the Earth extends between 2900 km and 5150 km depth accounting for 18% of the total planetary volume. Although mostly composed of iron, it contains impurities that lower its density and melting point with respect to pure Fe. Knowledge of the nature and content in light elements (O, S, Si, C) in the core has major implications for establishing the bulk composition of the Earth and for building models of Earth's differentiation. Angle dispersive X-ray diffraction experiments in double-sided laser heated diamond anvil cell (LH-DAC) were performed at ID27 beamline at the European Synchrotron Radiation Facility (ESRF) in Grenoble. In situ investigations enable determination of melting temperature and structural and density properties of the liquid alloys. Experiments were performed on the Fe-Ni-S alloy up to 160 GPa and 4000 K, on the Fe-Ni-Si alloy up to 91 GPa and 3200 K, on the Fe-FeO system up to 140 GPa and 4500 K and on the Fe-C system up to 80 GPa and 3500 K. Implications for the Earth's core temperature and composition will be discussed.

Morard, G.; Antonangeli, D.; Siebert, J.; Andrault, D.; Guignot, N.; Guyot, F. J.; Lord, O. T.; Garbarino, G.; Mezouar, N.

2013-12-01

25

Assessment of the possibility of core melt containment in a BBER-640 vessel  

Microsoft Academic Search

Melting of a reactor core is a multilevel process that can proceed along more than one path. Investigation of this process should be oriented toward studying the properties and quantitative ratios of phases forming conglomerates and melts in the core space. Data on the properties of the phases and their quantitative ratio can form a base for calculating the properties

A. D. Efanov; V. N. Korolev; Yu. I. Likhachev; A. A. Luk'yanov; A. V. Molchanov; E. V. Nomofilov; V. M. Troyanov; N. N. Shan'gin; Yu. S. Yur'ev

1996-01-01

26

Hydrogen generation during a core melt-coolant interactions. [PWR; BWR  

SciTech Connect

If a reactor accident leads to core melt, interaction of this material with coolant can produce hydrogen by steam oxidation of the metallic content of the melt. Experimental results are presented for hydrogen generation from both explosive and non-explosive melt-coolant interactions, using either iron-alumina or corium A + R as the melt simulant. Use of a simple model gives predictions for hydrogen generation rates that are in reasonable agreement with the experimental results.

Corradini, M.L.; Mitchell, D.E.; Evans, N.A.

1983-01-01

27

Core Formation: an Experimental Study of Metallic Melt-Silicate Segregation  

Microsoft Academic Search

To a large extent, the question of how metallic cores form reduces to the problem of understanding the surface tension between metallic melts and silicates [1]. This problem was addressed by performing experiments to determine the surface tensions between metallic melts with variable S contents and the silicate phases (olivine and orthopyroxene) expected in planetary mantles. The experiments were conducted

M. A. Herpfer; J. W. Larimer

1993-01-01

28

Inner core freezing and melting: Constraints from seismic body waves  

Microsoft Academic Search

Hypotheses for the mechanisms of growth of Earth’s inner core can be tested from observations of lateral variations of elastic and anelastic properties near the inner core boundary. Differential travel times of PKIKP–PKiKP and the apparent travel time of P waves diffracted around the inner core are consistent with the existence of a stably stratified, globally uniform, region of reduced

Vernon F. Cormier; Januka Attanayake; Kuang He

2011-01-01

29

INFLUENCE OF CORED WIRE MELTING MODE AT ARC SPRAYING ON COATING PROPERTIES  

Microsoft Academic Search

Jointly analysis of melting model of core wire at arc spraying and form- ing coating structure properties was done. Influence of physicochemical parameters of initial materials and atomization modes as well was established. Basing on investiga- tion results a row of core wires for wear-resistant application was developed. Coatings from such materials are successfully used with reference to parts to

Yu. Korobov; M. Filippov; V. Shymiakov; M. Shalimov

30

Review of experimental results of light water reactor core melt progression  

Microsoft Academic Search

This paper reports on results from integral-effects core melt progression experiments and from the examination of the damaged core of the Three Mile Island Unit 2 (TMI-2) reactor which are reviewed to gain insight on key severe accident phenomena. The experiments and the TMI-2 accident represent a wide variety of conditions and physical scales, yet several important phenomena appear to

R. R. Hobbins; D. A. Petti; O. J. Osetek; D. L. Hagrman

1991-01-01

31

Melting of the Fe-O-S system and reaction between olivine and iron melt at the lunar core conditions: Implications for the structure of the lunar core  

NASA Astrophysics Data System (ADS)

Despite recent observations on the Moon from satellite sensing and analyses of Apollo-era seismic data, there are still several unsolved issues on the deep lunar interior. Recent studies suggest the presence of a solid inner core and liquid outer core in the Moon (1). If we could constrain the temperature and composition of the lunar outer core, this would help us to better understand the lunar interior. Here, we focused on the interaction between liquid iron-alloys and solid silicates, and revealed the nature of the core of the Moon. The lunar mantle is characterized by high FeO content (2). This implies that the Moon is more oxidizing compared to the Earth and thus the lunar core could be composed of Fe-O-S alloys. It is known that there is a liquid immiscibility in the Fe-O-S system, thus one of the aims of our study is to clarify whether the Moon has an immiscible liquid core or not. We performed oxygen partition experiments between the lunar silicate mantle and molten metal at 5 GPa and calculated the distribution coefficient, D, of oxygen between liquid metal and olivine crystals. Using this value, the amount of O in the lunar liquid core is calculated to be 4.45 at.% at 1000 °C and 5.56 at.% at 1400 °C when the mantle Mg number is 80, which is the assumed lunar core (2). This high amount of oxygen strongly indicates that the lunar core coexisting with the FeO-rich mantle is composed of the two immiscible liquids (FeO-rich melt and Fe-FeS melt). Estimations from the existing data on the density of FeO-rich melt and liquid Fe-FeS indicate that the liquid Fe-FeS is denser than the FeO-rich melt suggesting that the lunar liquid core is stratified to an upper FeO-rich layer and a lower Fe-FeS layer. The upper FeO-rich layer is reactive with the olivine rich lunar mantle to form magnesiowustite and could cause the partially molten low Q (high damping) region at the CMB of the Moon. (1) Weber, R.C., Lin. P., Garnero, E.J., Williams, Q., Lognonné, P., Science 331, 309-312, (2011) (2) Taylor, S.R., Solar system evolution, A new Perspective. Cambridge University Press, New York, 307 (1992)

Akamatsu, H.; Ohtani, E.; Suzuki, A.

2013-12-01

32

Thermal interaction of core melt debris with the TMI2 baffle, core-former, and lower head structures  

Microsoft Academic Search

Recent inspection of the TMI-2 core-former baffle walls (vertical), former plates (horizontal), and lower plenum has been conducted to assess potential damage to these structures. Video observations show evidence of localized melt failure of the baffle walls, whereas fiberoptics data indicate the presence of resolidified debris on the former plates. Lower plenum inspection also confirms the presence of 20 tons

A. W. Cronenberg; E. L. Tolman

1987-01-01

33

Melt eruptions during molten corium concrete interactions  

NASA Astrophysics Data System (ADS)

The melt eruption phenomenon could occur during severe accidents at existing light water nuclear reactors. A postulated beyond-design basis accident includes the melting and relocation of the reactor core onto the concrete basemat of containment. The continually heated melt can reach high temperatures and thermally attack the underlying concrete, MCCI. As the melt cools, a crust forms on the upper surface of the melt pool. Melt eruptions occur when gases from the decomposing concrete passes through channels in the crust ejecting melt onto the upper surface of the crust. The impact of melt eruptions on the coolability of the melt is important when estimating the probability and timing of containment failure. This work focuses on understanding and modeling the melt eruption phenomenon. A model has been developed to predict the amount of melt ejected during melt eruptions. This entrainment model has been verified against an experimental database developed as part of this work. Several phenomena have been identified and modeled which may predict the creation and closure of eruptions sites. The models have been integrated into a MCCI systems code. The new melt eruption model predicted reasonable rates of melt ejection and the number and diameter of eruption sites for a sample simulation of a postulated reactor scale MCCI. Results from the new melt eruption model suggest an ex-vessel core melt under flooded conditions could readily quench.

Robb, Kevin Richard

34

Crystallization of ion clouds in octupole traps: Structural transitions, core melting, and scaling laws  

SciTech Connect

The stable structures and melting properties of ion clouds in isotropic octupole traps are investigated using a combination of semianalytical and numerical models, with a particular emphasis at finite-size scaling effects. Small-size clouds are found to be hollow and arranged in shells corresponding approximately to the solutions of the Thomson problem. The shell structure is lost in clusters containing more than a few thousands of ions, the inner parts of the cloud becoming soft and amorphous. While melting is triggered in the core shells, the melting temperature follows the rule expected for three-dimensional dense particles, with a depression scaling linearly with the inverse radius.

Calvo, F.; Champenois, C.; Yurtsever, E. [LASIM, Universite Claude Bernard Lyon 1 and CNRS, UMR 5579, 43 Boulevard du 11 Novembre 1918, F69622 Villeurbanne Cedex (France); PIIM, UMR 6633, Universite de Provence and CNRS, Campus Universitaire de Saint-Jerome C21, F13397 Marseille Cedex 20 (France); Koc University, Rumelifeneriyolu, Sariyer, Istanbul 34450 (Turkey)

2009-12-15

35

Investigations for Intrinsic Safety Againts Core Melt-down Accidents.  

National Technical Information Service (NTIS)

Large pool-type LMFBR present interesting safety features due to the big mass of sodium and to the possibility of using high pumping inertia. It would be possible to get intrinsic safety against core meltdown in the hypothetical case of heat removal accid...

G. Kayser R. Abdon M. Arslan P. Bergeonneau E. Gesi

1979-01-01

36

Computer Simulation for the Melting Curve Maximum Phenomenon ---Two-Species Soft-Core Model  

Microsoft Academic Search

Computer simulations by a Monte Carlo method are carried out for the two-species soft-core model to demonstrate an example of the melting curve maximum phenomena observed in many substances. In this model, atoms are assumed to have one excited internal level in which they have an effective radius smaller than that in the ground level. The atoms interact with each

Hisakazu Ogura; Hirotsugu Matsuda; Tohru Ogawa; Naofumi Ogita; Akira Ueda

1977-01-01

37

Possible reasons of shock melt deficiency in the Bosumtwi drill cores  

Microsoft Academic Search

Pre-drilling numerical modeling of the Bosumtwi impact event predicted a 200 m thick coherent melt layer, as well as abundant highly shocked target material within the central part of the crater structure. However, these predictions are in disagreement with data from drill core obtained in 2004-2005. Here I provide a brief overview of previous results and discuss possible reasons behind

N. Artemieva

2007-01-01

38

Contribution of Anticipated Transients Without Scram (ATWS) to core melt at United States nuclear power plants  

Microsoft Academic Search

This report looks at WASH-1400 and several other Probabilistic Risk Assessments (PRAs) and Probabilistic Safety Studies (PSSs) to determine the contribution of Anticipated Transients Without Scram (ATWS) events to the total core melt probability at eight nuclear power plants in the United States. After considering each plant individually, the results are compared from plant to plant to see if any

Giachetti

1989-01-01

39

Centrifuge assisted percolation of Fe–S melts in partially molten peridotite: Time constraints for planetary core formation  

Microsoft Academic Search

The mechanism which segregates molten Fe–S into metallic cores of planetary bodies is still not fully understood. Due to the high interfacial energy and wetting angle between Fe–S melts and silicate mantle minerals, the continuous percolative flow of such melts cannot be efficient for the core segregation in planetary bodies. A series of percolation experiments has been realized on a

N. Bagdassarov; G. Solferino; G. J. Golabek; M. W. Schmidt

2009-01-01

40

Method and arrangement for reducing the radiation exposure risks in the course of a nuclear reactor core melt down accident  

SciTech Connect

A method and arrangement are described for containing the core melt flowing from a nuclear reactor into a core catcher below the core wherein the core melt is permitted to gradually penetrate layers of a core catcher materials of inorganic reactor soluble oxides or salts disposed in the core catcher which core catcher materials are dissolved by the oxidic part of the core melt. The molten solution, after solidification and after being cooled down to a temperature at which hydrogen generating reactions do not take place, is leached with water and rinsed out of the core catcher without the need for humans to be present in the reactor containment and to be exposed to radiation.

Donne, M.D.; Dorner, S.; Schumacher, G.

1981-11-17

41

Containment performance for the core melt accidents in BWRs with Mark I and Mark II containments  

SciTech Connect

Most previous risk assessment studies have assumed catastrophic failure of containments for severe accidents which are predicted to exceed the containment yield stress. This investigation analyzes the progression of a severe accident in order to develop realistic containment temperature and pressure loading, utilizes models for containment leakage estimates for the various loading histories, and assesses the expected failure modes and timing of releases for core melt accidents in Boiling Water Reactors (BWRs) with Mark I and Mark II containments. The results of the investigation indicate that leakage through the seal on the drywell head may be sufficient to prevent catastrophic failure of the containments for a wide range of hypothetical core melt scenarios. In addition, the investigation has indicated the potential for a previously inidentified failure mode (containment liner meltthrough) for Mark I containments in which a large fraction of the core is released from the vessel in a molten state. 14 refs.

Perkins, K.R.; Yang, J.W.; Greene, G.A.; Pratt, W.T.; Hofmayer, C.

1985-01-01

42

Silicate melt inclusions and glasses in lunar soil fragments from the Luna 16 core sample  

USGS Publications Warehouse

More than 2000 fragments were studied microscopically, and electron microprobe analyses were made of 39 selected areas, from a few square mm of polished surface, through 75- to 425-??m fragments of lunar soil from two samples of the Luna 16 core. The silicate melt inclusions and glasses differ in important details from those observed earlier in the Apollo samples. Melt inclusions in olivine contain epitaxially oriented daughter crystals, but also show a similar epitaxy around the outside of the crystals not observed in previous lunar samples. Melt inclusions in ilmenite suggest trapping at successive stages in a differentiation sequence. There is abundant evidence for late-stage silicate liquid immiscibility, with melt compositions similar but not identical to those from Apollo 11 and 12. A comparison of the alkali ratio of any given bulk rock analysis with that of its late-stage, high-silica melt shows gross differences for different rocks. This is pertinent to understanding late-stage differentiation processes. Glass fragments and spherules exhibit a wide range of crystallization textures, reflecting their wide range of compositions and cooling histories. No significant differences were found between the two portions of core examined (Zones A and D). ?? 1972.

Roedder, E.; Weiblen, P. W.

1972-01-01

43

Core Formation: an Experimental Study of Metallic Melt-Silicate Segregation  

NASA Astrophysics Data System (ADS)

To a large extent, the question of how metallic cores form reduces to the problem of understanding the surface tension between metallic melts and silicates [1]. This problem was addressed by performing experiments to determine the surface tensions between metallic melts with variable S contents and the silicate phases (olivine and orthopyroxene) expected in planetary mantles. The experiments were conducted in a piston-cylinder apparatus at P = 1GPa and T = 1250-1450 degrees C. Textural and chemical equilibration was confirmed in several ways: theoretical estimates were checked by conducting a series of experiments at progressively longer times (up to 72 hrs) until phase composition and dihedral angle ceased to change and the distribution of measured "apparent" angles matched the standard cumulative frequency curve. The dihedral "wetting" angles (theta) were measured from high resolution photomicrgraphs using a 10X optical protractor; 100-400 measurements were made for most experiments. The dihedral angle is related to the ratio of interfacial energies: gamma(sub)ss/gamma(sub)sl = 2 cos(theta/2), where gamma(sub)ss and gamma(sub)sl are the interfacial energies between solid-solid and liquid-solid. Since data exist for the pertinent solid-solid energies, the liquid-solid interfacial energies can be computed from measured theta values. However, the important relations are best expressed in terms of theta values. The extent to which a melt is interconnected along grain boundaries, and hence able to flow and segregate depends on the value of theta and the fraction of melt present. When theta < 60 degrees, the liquid can be interconnected at all melt fractions but when theta > 60 degrees, the melt fraction must be at least 1 vol% and increses as theta increases. Actually there is a predicted effect, analogous to a hysteresis effect, where for a given theta value the amount of melt that needs to be added for interconnection is greater than the amount left when the melt disconnects (pinches off). In our experiments, where dense metallic melt drained away, the disconnect theta values match the theoretical predictions. The composition of the metallic melt in the experiments was varied from stoichiometric FeS to Fe/S ratios near the the eutectic and on to more Fe rich compositons. The theta values vary in a systematic manner; for example, for melts in contact with olivine at 1300 degrees C the theta values range from 67 degrees for FeS to 55 degrees at the eutectic and back toward higher values at higher Fe contents. Theoretical considerations indicate that eutectic compositions are expected to have the lowest theta values, just as observed. The theta values indicate that melts with eutectic composition can interconnect and segregate at 1-2 vol% melt fraction at 1300 degrees C. Some previous estimates of the melt fraction required for interconnection are much higher [2,3], but the inferences were drawn from experiments that were not designed to test for textural equilibrium, fraction of melt present, etc. The present experiments clearly show that metallic melts can readily segregate from solid silicates. Simple extrapolations to other phases, compositions and PT conditions provide a rather complete picture of how the "plumbing" worked in the mantles of planetary objects during the initial stages of core segregation. References: [1] Stevenson D. J. (1990) In Origin of the Earth, 231-249. [2] Taylor G. J. (1989) LPSC XX, 1109. [3] Walker D. and Agee C. B. Meteor. 23, 81-91.

Herpfer, M. A.; Larimer, J. W.

1993-07-01

44

Ab initio melting curve of iron at extreme pressures: implications for exoplanets' cores  

NASA Astrophysics Data System (ADS)

Exoplanets with masses similar to that of Earth have recently been discovered1. A first order question for understanding their dynamics is to know whether they possess Earth like liquid metallic cores. However, the iron melting curve is unknown at conditions corresponding to planets of several times the Earth's mass (over 15 Mbar for planets with 10 times the Earth’s mass (ME)2). In the density-temperature region of the cores of those super-Earths, we calculate the iron melting curve using first principle molecular dynamics simulations based on density functional theory. By comparing calculated thermal profiles of Super Earths, we show that planets heavier than 3-5 ME have solid cores, thus precluding the existence of an internal magnetic field. This new field of investigation of the iron melting curve shows that the Earth may be close to the maximal size for a terrestrial planet to possess a partially molten metallic core. References 1 J. P. Beaulieu, D. P. Bennett, P. Fouque et al., Nature 439 (7075), 437 (2006). 2 D. Valencia, R. J. O'Connell, and D. Sasselov, Icarus 181, 545 (2006).

Bouchet, J.; Morard, G.; Valencia, D. C.; Mazevet, S.; Guyot, F. J.

2010-12-01

45

Anomalous Melting Scenario of the Two-Dimensional Core-Softened System  

NASA Astrophysics Data System (ADS)

We present a computer simulation study of the phase behavior of two-dimensional (2D) classical particles repelling each other through an isotropic core-softened potential. As in the analogous three-dimensional (3D) case, a reentrant-melting transition occurs upon compression for not too high pressures, along with a spectrum of waterlike anomalies in the fluid phase. However, in two dimensions in the low density part of the phase diagram melting is a continuous two-stage transition, with an intermediate hexatic phase. All available evidence supports the Kosterlitz-Thouless-Halperin-Nelson-Young scenario for this melting transition. On the other hand, at the high density part of the phase diagram one first-order transition takes place.

Dudalov, D. E.; Fomin, Yu. D.; Tsiok, E. N.; Ryzhov, V. N.

2014-04-01

46

Earliest step of core-mantle separation: Shock melting experiment of chondrite-like materials  

NASA Astrophysics Data System (ADS)

In order to understand the dynamic melting process during the planet accretion stage, we carried out shock melting experiments on chondrite-like starting materials, mixture of Fe-metal and peridotite KLB-1 (Takahashi, 1986) with various proportion of Fe metal sponge. Six shock experiments were carried out using a propellant gun (30 mm bore) at the NIMS, using methods similar to Hirata et al. (2009PEPI). In shock recovered samples, melting took place only locally and numerous metal droplets were formed in molten part of the sample. Large Fe-droplets up to 50 micron in diameter were formed in the center of the sample (Fig.1a) which indicates that growth of Fe-metal droplets took place in less than 1/100 sec. In contrast to the very slow growth rate of FeS melts dispersed in partially molten peridotite (Yoshino & Watson, 2005), large Fe-metal droplets formed in shock melting experiments must represent the volume of Fe that had been three dimensionally connected prior to shock melting. Size of the metal grains formed in shock melting process in planet building stage may depend on the connectivity of Fe-metal phase in the source materials. In order to test the above hypothesis, we carried out 40 experiments using a piston-cylinder apparatus at the Magma Factory, Tokyo Institute of Technology using the same starting materials. In the PC experiments, pressure was kept constant at 1 GPa. Sample temperatures were raised quickly to 1300C and then hold for 10 min (just above the solidus of peridotite KLB-1 at 1 GPa). Temperature was raised very quickly from 1300 to 1600C and quenched. Sample temperature was controlled so that the total time for melting of Fe (>1550C) to be 10 to 1800sec. Graphite capsule was used for short experiments whereas MgO was used in longer experiments (>60sec). Textures of the melted samples are similar to those by the propellant gun experiments at iron poor sample. In iron rich samples, however, up to millimeter scale very large Fe-grains were formed even in shortest runs (Fig.1b, 1600C 10 sec). Based on these experiments, we conclude that size of the metal grains formed in each shock melting process in planet building stage depends on the connectivity of Fe-metal phase in the source materials. Pallasite (stony-iron meteorite) may represent the product of local melt pockets formed after impacts, the earliest form of core-mantle separation in planet building stage.

Eiichi, T.; Tsumagari, Y.; Nishio, M.; Sekine, T.

2009-12-01

47

Melt in the impact breccias from the Eyreville drill cores, Chesapeake Bay impact structure, USA  

Microsoft Academic Search

The center of the 35.3 Ma Chesapeake Bay impact structure (85 km diameter) was drilled during 2005\\/2006 in an ICDP-0USGS drilling project. The Eyreville drill cores include polymict impact breccias and associated rocks (1397-01551 m depth). Tens of melt particles from these impactites were studied by optical and electron microscopy, electron microprobe, and microRaman spectroscopy, and classified into six groups:

Katerina Bartosova; Lutz Hecht; Christian Koeberl; Eugen Libowitzky; Wolf Uwe Reimold

2011-01-01

48

Hot-melt extruded ethylcellulose cylinders containing a HPMC–Gelucire® core for sustained drug delivery  

Microsoft Academic Search

The objective of the study was to develop a sustained release system consisting of a hot-melt extruded ethylcellulose pipe surrounding a drug-containing hydroxypropyl methylcellulose (HPMC)–Gelucire® 44\\/14 core, yielding a monolithic matrix system applicable in the domain of sustained drug release. The influence of HPMC substitution type and viscosity grade was investigated through dissolution testing and erosion studies. All sustained release

E Mehuys; C Vervaet; J. P Remon

2004-01-01

49

Feasibility study for a containment to resist core-melt accidents  

Microsoft Academic Search

A feasibility study has been performed for a light water reactor containment able to resist even severe accidents by passive means. Upper-bound design loads have been considered for all physically possible scenarios after a core-melt accident as determined by Kernforschungszentrum Karlsruhe. The essential layout of this containment is presented. Based on the main system features of a German 1,300-MW Convoy

J. Butsch; F. H. Schlueter; J. Eibl

1995-01-01

50

An Interconnected Network of Core-Forming Melts Produced by Shear Deformation  

NASA Technical Reports Server (NTRS)

The formation mechanism of terrestrial planetary is still poorly understood, and has been the subject of numerous experimental studies. Several mechanisms have been proposed by which metal-mainly iron with some nickel-could have been extracted from a silicate mantle to form the core. Most recent models involve gravitational sinking of molten metal or metal sulphide through a partially or fully molten mantle that is often referred to as a'magma ocean. Alternative models invoke percolation of molten metal along an interconnected network (that is, porous flow) through a solid silicate matrix. But experimental studies performed at high pressures have shown that, under hydrostatic conditions, these melts do not form an interconnected network, leading to the widespread assumption that formation of metallic cores requires a magma ocean. In contrast, here we present experiments which demonstrate that shear deformation to large strains can interconnect a significant fraction of initially isolated pockets of metal and metal sulphide melts in a solid matrix of polycrystalline olivine. Therefore, in a dynamic (nonhydrostatic) environment, percolation remains a viable mechanism for the segregation and migration of core-forming melts in a solid silicate mantle.

Bruhn, D.; Groebner, N.; Kohlstedt, D. L.

2000-01-01

51

Melt stagnation in peridotites from the Godzilla Megamullion Oceanic Core Complex, Parece Vela Basin, Philippine Sea  

NASA Astrophysics Data System (ADS)

The Godzilla Megamullion, located in the Parece Vela Backarc Basin of the Izu-Bonin-Mariana (IBM) system, is the largest known example of an Oceanic Core Complex (OCC). Peridotites recovered from the megamullion are divided petrographically into fertile (e.g. lherzolites), depleted (e.g. harzburgites), and plagioclase-bearing groups (Ohara et al., 2003a). A total of 151 thin sections were studied from the Kairei KR03-01, Hakuho Maru KH07-02, and Yokosuka YK09-05 cruises. Melt stagnation is studied via the incidence of plagioclase-bearing peridotites and the major element chemistry of Cr-spinels in the plag-bearing samples. A distinct trend in melt stagnation is evident along the length of the megamullion representing a secular evolution in the entrapment of melts rising through the lithosphere. The distal (furthest from the termination of spreading), depleted portion of the mullion represents a robust mantle section that was still producing abundant melt and can be compared to typical oceanic spreading with its relatively "normal" percentage of plagioclase peridotites and average spinel Cr# of 0.35. The medial, fertile portion of the mullion represents a steep falloff in melt productivity represented by fertile spinel compositions (i.e. Cr# < 0.25) and the presence of plagioclase-free lherzolites. The proximal (closest to termination of spreading), heavily plagioclase impregnated portion (with spinel Cr#s covering nearly the entire range of abyssal peridotite spinel compositions) of the mullion then represents a period of increasing stagnation of melt into a lithosphere that was undergoing progressive thickening. We infer that the processes of mantle evolution through melt stagnation and impregnation, as evidenced by the systematic variations in plag-peridotites along Godzilla Megamullion, represent a possibly common way in which the mantle reacts to OCC formation. In this case, Godzilla Megamullion may represent an extreme endmember in OCC formation.

Loocke, Matthew; Snow, Jonathan E.; Ohara, Yasuhiko

2013-12-01

52

Sulfur Saturation Limits in Silicate Melts and their Implications for Core Formation Scenarios for Terrestrial Planets  

NASA Technical Reports Server (NTRS)

This study explores the controls of temperature, pressure, and silicate melt composition on S solubility in silicate liquids. The solubility of S in FeO-containing silicate melts in equilibrium with metal sulfide increases significantly with increasing temperature but decreases with increasing pressure. The silicate melt structure also exercises a control on S solubility. Increasing the degree of polymerization of the silicate melt structure lowers the S solubility in the silicate liquid. The new set of experimental data is used to expand the model of Mavrogenes and O'Neill(1999) for S solubility in silicate liquids by incorporating the influence of the silicate melt structure. The expected S solubility in the ascending magma is calculated using the expanded model. Because the negative pressure dependence of S solubility is more influential than the positive temperature dependence, decompression and adiabatic ascent of a formerly S-saturated silicate magma will lead to S undersaturation. A primitive magma that is S-saturated in its source region will, therefore, become S-undersaturated as it ascends to shallower depth. In order to precipitate magmatic sulfides, the magma must first cool and undergo fractional crystallization to reach S saturation. The S content in a metallic liquid that is in equilibrium with a magma ocean that contains approx. 200 ppm S (i.e., Earth's bulk mantle S content) ranges from 5.5 to 12 wt% S. This range of S values encompasses the amount of S (9 to 12 wt%) that would be present in the outer core if S is the light element. Thus, the Earth's proto-mantle could be in equilibrium (in terms of the preserved S abundance) with a core-forming metallic phase.

Holzheid, Astrid; Grove, Timothy L.

2002-01-01

53

Sulfur Saturation Limits in Silicate Melts and their Implications for Core Formation Scenarios for Terrestrial Planets  

NASA Technical Reports Server (NTRS)

This study explores the controls of temperature, pressure, and silicate melt composition on S solubility in silicate liquids. The solubility of S in FeO-containing silicate melts in equilibrium with metal sulfide increases significantly with increasing temperature but decreases with increasing pressure. The silicate melt structure also exercises a control on S solubility. Increasing the degree of polymerization of the silicate melt structure lowers the S solubility in the silicate liquid. The new set of experimental data is used to expand the model of Mavrogenes and O Neill (1999) for S solubility in silicate liquids by incorporating the influence of the silicate melt structure. The expected S solubility in the ascending magma is calculated using the expanded model. Because the negative pressure dependence of S solubility is more influential than the positive temperature dependence, decompression and adiabatic ascent of a formerly S-saturated silicate magma will lead to S undersaturation. A primitive magma that is S-saturated in its source region will, therefore, become S-undersaturated as it ascends to shallower depth. In order to precipitate magmatic sulfides, the magma must first cool and undergo fractional crystallization to reach S saturation. The S content in a metallic liquid that is in equilibrium with a magma ocean that contains -200 ppm S (Le., Earth s bulk mantle S content) ranges from 5.5 to 12 wt% S. This range of S values encompasses the amount of S (9 to 12 wt%) that would be present in the outer core if S is the light element. Thus, the Earth s proto-mantle could be in equilibrium (in terms of the preserved S abundance) with a core-forming metallic phase.

Holzheid, Astrid; Grove, Timothy L.

2003-01-01

54

The timing of partial melting, Barrovian metamorphism and granite intrusion in the Naxos metamorphic core complex, Cyclades, Aegean Sea, Greece  

Microsoft Academic Search

The relationship between partial melting and granite intrusion in a classic Barrovian metamorphic terrane has been assessed. Thirteen samples were dated by SHRIMP U–Pb zircon geochronology from the island of Naxos, Greece, one of the Aegean metamorphic core complexes. The effect of partial melting during peak Barrovian metamorphism on Naxos is recorded by fine (

Sue Keay; Gordon Lister; Ian Buick

2001-01-01

55

Accretion and core formation on Mars: molybdenum contents of melt inclusion glasses in three SNC meteorites  

NASA Astrophysics Data System (ADS)

Molybdenum, cerium, barium, yttrium, and rubidium contents of glasses in melt inclusions in three SNC meteorites (LEW 88516, Governador Valadares, and Chassigny) have been measured by ion microprobe. Ratios of Mo/Ba and Mo/Ce have been used to estimate the Mo content of the primitive Martian mantle, 120 ± 60 ppb. Abundances of five moderately siderophile elements (Ni, Co, Mo, W, and P) and Re in the Martian mantle are consistent with metal-silicate equilibrium between S-bearing metallic liquid (in a core 22 wt% of the planet) and peridotite melt at 75 kb, 1620°C, and oxygen fugacity 1.4 log fO 2 units below the IW buffer. This homogeneous accretion scenario is different than many heterogeneous accretion models for the Earth, but similar to recent studies suggesting homogeneous accretion in the presence of a deep terrestrial magma ocean.

Righter, Kevin; Hervig, Richard L.; Kring, David A.

1998-06-01

56

Quantification of Dead-ice Melting in Ice-Cored Moraines at the High-Arctic Glacier Holmströmbreen, Svalbard  

NASA Astrophysics Data System (ADS)

An extensive dead-ice area has developed at the stagnant snout of the Holmströmbreen glacier on Svalbard following its Little Ice Age maximum. Dead-ice appears mainly as ice-cored moraines, ice-cored eskers and ice- cored kames. The most common dead-ice landform is sediment gravity flows on ice-cored slopes surrounding a large ice-walled, moraine-dammed lake. The lake finally receives the sediment from the resedimentation processes. Dead-ice melting is described and quantified through field studies and analyses of high-resolution, multi-temporal aerial photographs and satellite imagery. Field measurements of backwasting of ice-cored slopes indicate short-term melting rates of c. 9.2 cm/day. Long-term downwasting rates indicate a surface lowering of ice-cored moraines of c. 0.9 m/yr from 1984-2004. Different measures for dead-ice melting are assessed in relation to the temperature record from Svalbard since the termination of the Little Ice Age. The most prominent impact of dead-ice melting is the evolution of the ice-walled lake with an area increasing near-exponentially over the last 40 years. As long as backwasting and mass movement processes prevent build-up of an insulating debris-cover and expose ice-cores to melting, the de-icing continues even though the area is characterized by continuous permafrost.

Schomacker, A.; Kjaer, K. H.

2007-12-01

57

Partitioning of potassium between silicates and sulphide melts - Experiments relevant to the earth's core.  

NASA Technical Reports Server (NTRS)

The partitioning of potassium between roedderite, K2Mg5Si12O30 and an Fe-FeS melt was investigated at temperatures about 40 C above the Fe-FeS eutectic. Roedderite was considered a prime candidate for one of the potassium-bearing phases in the primitive earth because roedderite and merrihueite are the only two silicates containing essential potassium which have been identified in stony meteorites. Application of the results to a primitive chondritic earth is discussed, and it is concluded that extraction of most of the earth's potassium into the Fe-FeS core would occur under the conditions in the early earth.-

Goettel, K. A.

1972-01-01

58

Comparison of the effect of hazard and response/fragility uncertainties on core melt probability uncertainty  

SciTech Connect

This report proposes a method for comparing the effects of the uncertainty in probabilistic risk analysis (PRA) input parameters on the uncertainty in the predicted risks. The proposed method is applied to compare the effect of uncertainties in the descriptions of (1) the seismic hazard at a nuclear power plant site and (2) random variations in plant subsystem responses and component fragility on the uncertainty in the predicted probability of core melt. The PRA used is that developed by the Seismic Safety Margins Research Program.

Mensing, R.W.

1985-01-01

59

Aerosol and melt chemistry in the ACE molten core-concrete interaction experiments  

SciTech Connect

Experimental results are discussed from the internationally sponsored Advanced Containment Experiments (ACE) Program on the melt behavior and aerosols released during the interaction of molten reactor core material with concrete. A broad range of parameters were addressed in the experimental program: Seven large-scale tests were performed using four types of concrete (siliceous, limestone/sand, serpentine, and limestone) and a range of metal oxidations for both boiling water and pressurized waster reactor core debris. The release aerosols contained mainly constitutents of the concrete. In the tests with metal and limestone/sand siliceous concrete, silicon compounds comprised 50% or more of the aerosol mass. Releases of uranium and low-volatility fission-product elements were small in all tests. Releases of tellurium and neutron absorber materials (silver, indium, and boron from boron carbide) were high.

Fink, J.K.; Thompson, D.H.; Spencer, B.W. [Argonne National Laboratory, IL (United States); Sehgal, B.R. [Royal Inst. of Tech., Stockholm (Sweden)

1995-01-01

60

Phase relations, melting and thermoelastic properties in FeS: Application to the Martian core  

NASA Astrophysics Data System (ADS)

The phase stability and equations of state of the NiAs superstructured FeS IV phase and the high-temperature NiAs structured FeS V phase (space group P63/mmc) have implications for the structure and dynamics of planetary cores, such as that of Mars. The FeS VI phase (space group Pnma) is stable to the conditions of the deep Earth, and has implications specifically for the Earth's liquid outer core, including the nature of the light-element component required to match the density deficit relative to pure Fe in the core. A suite of high-pressure, high-temperature X-ray diffraction data were collected on stoichiometric FeS at pressures and temperature conditions of terrestrial planetary interiors using a laser-heated diamond anvil cell. Experiments were performed at beamline 13-ID-D (GSECARS) at the Advanced Photon Source. We refined the high-temperature, high-pressure phase boundaries of the FeS IV, FeS V and FeS VI polymorphs, and also established their thermal equations of state. The phase transition from FeS IV to FeS V is indicated by the disappearance of some or all of the following FeS IV reflections: 110, 210, 112, 211, 300, 302, 303. Fixing K?0 at 4 and q at 1, we find V0 = 16.4 cc mol-1 and 16.9 cc mol-1, K0T = 98.7 GPa and 91.6 GPa, and ?0 = 2.15 and 1.47 for the FeS IV and FeS V phases, respectively. Using a combination of static compression measurements in Ne and high-temperature PVT measurements, our data suggest a higher FeS VI transition pressure than previous studies. Comparing our results to the Martian core, we find that the stable phase at the core-mantle boundary is FeS IV, with a possible transition to FeS V occurring deeper in the Martian core, while the stability field of FeS VI exceeds PT conditions of the Martian core. At approximately 40 GPa, we observe melting of FeS V consistent with the melting curve of Boehler (1992).

Reaman, D. M.; Campbell, A. J.; Fischer, R. A.; Heinz, D. L.; Prakapenka, V.

2012-12-01

61

How dimensionality changes the anomalous behavior and melting scenario of a core-softened potential system?  

PubMed

We present a computer simulation study of the phase diagram and anomalous behavior of two-dimensional (2D) and three-dimensional (3D) classical particles repelling each other through an isotropic core-softened potential. As in the analogous three-dimensional case, in 2D a reentrant-melting transition occurs upon compression under not too high pressure, along with a spectrum of thermodynamic and dynamic anomalies in the fluid phase. However, in two dimensions the order of the region of anomalous diffusion and the region of structural anomaly is inverted in comparison with the 3D case, where there exists a water-like sequence of anomalies, and has a silica-like sequence. In the low density part of the 2D phase diagram, melting is a continuous two-stage transition, with an intermediate hexatic phase. All available evidence supports the Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) scenario for this melting transition. On the other hand, at high density part of the phase diagram one first-order transition takes place. PMID:24888366

Dudalov, D E; Fomin, Y D; Tsiok, E N; Ryzhov, V N

2014-07-21

62

Melting relation of Fe-O-S alloy up to the outer core pressure: Implication to temperature of the Earth's core  

NASA Astrophysics Data System (ADS)

The Earth’s core consists of the liquid outer core and the solid inner core, suggesting that the temperature at a boundary of the inner/outer core (ICB) corresponds to the melting temperature of the core composing Fe-alloy. Thus, the information of melting temperature of Fe-alloy under high pressure is important to clarify the thermal structure of the Earth’s core. Sulphur and oxygen have been considered as major candidates of the light elements due to its high solar abundance and high solubility into iron even at low or moderate pressures and temperatures. In this study, we have performed in situ X-ray diffraction experiment under high pressure and temperature and determined solidus and liquidus temperatures of Fe-O-S alloy up to the outer core condition using a laser-heated diamond anvil cell. Fe, Fe3S, and FeO phases are stable at subsolidus conditions. Fe3S phase melts first at the temperature close to the eutectic point of Fe-Fe3S system. Then FeO melts at several 100 K higher than the solidus temperature and Fe corresponds to a liquidus phase in this system. The liquidus temperature is found to be 260-670 K lower than the melting temperature of pure Fe due to the alloying effect of S and O. Based on the present results, the temperatures at the core/mantle boundary (TCMB) and at the ICB (TICB) are estimated to be TCMB>3050 K and 4400< TICB<5600 K. The present results provide important constraint on the thermal structure of the core.

Terasaki, H.; Kamada, S.; Sakai, T.; Ohtani, E.; Hirao, N.; Sata, N.; Ohishi, Y.

2010-12-01

63

Nickel and helium evidence for melt above the core-mantle boundary.  

PubMed

High (3)He/(4)He ratios in some basalts have generally been interpreted as originating in an incompletely degassed lower-mantle source. This helium source may have been isolated at the core-mantle boundary region since Earth's accretion. Alternatively, it may have taken part in whole-mantle convection and crust production over the age of the Earth; if so, it is now either a primitive refugium at the core-mantle boundary or is distributed throughout the lower mantle. Here we constrain the problem using lavas from Baffin Island, West Greenland, the Ontong Java Plateau, Isla Gorgona and Fernandina (Galapagos). Olivine phenocryst compositions show that these lavas originated from a peridotite source that was about 20 per cent higher in nickel content than in the modern mid-ocean-ridge basalt source. Where data are available, these lavas also have high (3)He/(4)He. We propose that a less-degassed nickel-rich source formed by core-mantle interaction during the crystallization of a melt-rich layer or basal magma ocean, and that this source continues to be sampled by mantle plumes. The spatial distribution of this source may be constrained by nickel partitioning experiments at the pressures of the core-mantle boundary. PMID:23302797

Herzberg, Claude; Asimow, Paul D; Ionov, Dmitri A; Vidito, Chris; Jackson, Matthew G; Geist, Dennis

2013-01-17

64

The Effects of Summertime Melt on Stable Water Isotopes: Implications for Paleotemperature Reconstructions from Firn Core Records  

Microsoft Academic Search

A firn core was drilled on the Prince of Wales (POW) Icefield, Ellesmere Island, Nunavut, in the spring of 2001. While this firn core was drilled on the high northern plateau of the Icefield, its location is still prone to occasional summertime melt events. Annual delta18O amplitudes of 5.7±2.30\\/00 persist in the firn core stratigraphy indicating that the degree of

T. Moran; S. J. Marshall

2008-01-01

65

Melting and solid-melt partitioning in iron-light element systems under megabar conditions: Implications for the thermal state of the Core  

NASA Astrophysics Data System (ADS)

The experimental study of the core was pioneered by H.K. Mao [1]. After his pioneering works, significant developments have been made in our high pressure science community to clarify the Earth's core. We have extended the pressure range of melting experiments of iron-light element compounds to pressures exceeding 100 GPa. Melting can be detected by using different criteria, i.e., a change of laser heating efficiency, in situ X-ray diffraction, and the textural change of the recovered samples after quenching from melts. These criteria are generally consistent with one another and enabled us to constrain the temperature, thermal state, and the composition of the core. Melting and phase relations of the Fe-Si, Fe-S, Fe-Ni-S and Fe-S-O systems were determined up to the core pressures based on the in situ X-ray diffraction and a change of laser heating efficiency and texture of the recovered samples by the laser heated diamond anvil cell [2,3,4]. The melting curves may provide constraints for temperatures at the core-mantle boundary (CMB) and the inner core boundary (ICB). Melting and phase relations of the Fe-Fe3S and Fe-S-O systems revealed that Fe3S dissolves first at the solidus before melting of the metallic iron alloy at the liquidus at least up to 180 GPa. The (FeNi)3S phase together with hcp-FeNi is stable up to the pressure above 200 GPa. Therefore, these phases are candidates for the constituent of the inner core. Solid-liquid partitioning experiments can be made by the laser heated diamond anvil cell. The partitioning experiment of Pt, Re, and Os between solid hcp-FeNi alloy and Fe-Ni-S liquid metals is an example of such experiments. It has been assumed that Os isotopic signatures showing coupled 186Os/188Os and 187Os/188Os enrichments in some plume magmas is originated from contamination of outer core materials formed by the inner core fractionation at the base of the lower mantle [5]. We conducted partitioning experiments of Pt, Re, and Os up to 100 GPa to test this hypothesis [6]. Quench textures from the melts were clearly observed in polished run products. On the basis of the chemical analysis by EPMA and/or SIMS of the recovered samples, we determined partition coefficients D(solid/liqid) of Pt, Re, and Os between solid and liquid metal phases. The partition coefficients increase with increasing sulfur content of the liquid, whereas they decrease with increasing pressure. The result indicates that it is unlikely that the required Pt-Re-Os fractionation for producing the Os isotopic signature was generated during inner core crystallization.

Ohtani, E.; Kamada, S.; Sakai, T.; Terasaki, H.; Hayashi, H.

2011-12-01

66

In-situ rock melting applied to lunar base construction and for exploration drilling and coring on the moon  

SciTech Connect

An excavation technology based upon melting of rock and soil has been extensively developed at the prototype hardware and conceptual design levels for terrestrial conditions. Laboratory and field tests of rock-melting penetration have conclusively indicated that this excavation method is insensitive to rock, soil types, and conditions. Especially significant is the ability to form in-place glass linings or casings on the walls of boreholes, tunnels, and shafts. These factors indicate the unique potential for in situ construction of primary lunar base facilities. Drilling and coring equipment for resource exploration on the moon can also be devised that are largely automated and remotely operated. It is also very likely that lunar melt-glasses will have changed mechanical properties when formed in anhydrous and hard vacuum conditions. Rock melting experiments and prototype hardware designs for lunar rock-melting excavation applications are suggested.

Rowley, J.C.; Neudecker, J.W.

1984-01-01

67

Partitioning of Moderately Siderophile Elements Among Olivine, Silicate Melt, and Sulfide Melt: Constraints on Core Formation in the Earth and Mars  

NASA Technical Reports Server (NTRS)

This study investigates the effects of Variations in the fugacities of oxygen and sulfur on the partitioning of first series transition metals (V, Cr, Mn, Fe, Co, Ni. and Cu) and W among coexisting sulfide melt, silicate melt, and olivine. Experiments were performed at 1 atm pressure, 1350 C, with the fugacities of oxygen and sulfur controlled by mixing CO2, CO, and SO2 gases. Starting compositions consisted of a CaO-MgO-Al2O3-SiO2-FeO-Na2O analog for a barred olivine chondrule from an ordinary chondrite and a synthetic komatiite. The f(sub O2)/f(sub S2), conditions ranged from log of f(sub O2) = -7.9 to - 10.6, with log of f(sub S2) values ranging from - 1.0 to -2.5. Our experimental results demonstrate that the f(sub O2)/f(sub S2) dependencies of sulfide melt/silicate melt partition coefficients for the first series transition metals arc proportional to their valence states. The f(sub O2)/f(sub S2) dependencies for the partitioning of Fe, Co, Ni, and Cu are weaker than predicted on the basis of their valence states. Variations in conditions have no significant effect on olivine/melt partitioning other than those resulting from f(sub O2)-induced changes in the valence state of a given element. The strong f(sub O2)/f(sub S2) dependence for the olivine/silicate melt partitioning of V is attributable to a change of valence state, from 4+ to 3+, with decreasing f(sub O2). Our experimentally determined partition coefficients are used to develop models for the segregation of sulfide and metal from the silicate portion of the early Earth and the Shergottite parent body (Mars). We find that the influence of S is not sufficient to explain the overabundance of siderophile and chalcophile elements that remained in the mantle of the Earth following core formation. Important constraints on core formation in Mars are provided by our experimental determination of the partitioning of Cu between silicate and sulfide melts. When combined with existing estimates for siderophile element abundances in the Martian mantle and a mass balance constraint from Fe, the experiments allow a determination of the mass of the Martian core (approx. 17 to 22 wt% of the planet) and its S content (approx.0.4 wt%). These modeling results indicate that Mars is depleted in S, and that its core is solid.

Gaetani, Glenn A.; Grove, Timothy L.

1997-01-01

68

A unified approach for calculating core melt frequency caused by internal and external initiating events  

SciTech Connect

A unified approach for calculating the core melt frequency of a specific reactor caused by both internal and external accident initiators is demonstrated. Two classes of internal initiators are examined: transients, of which turbine trip is the chosen example; and loss-of-coolant events of various sizes. The concepts of hazard and fragility analysis first proposed for seismic risk analysis are linked to the frequencies of internal initiating events, and to the plant response as a function of the event intensity. Uncertainties are propagated using discrete probability distribution (DPD) arithmetic. Advantages of this approach include mathematical and conceptual consistency, and an improved uncertainty analysis, which are important considerations if risk studies are to be utilized in decision-making based on quantitative safety goals. 5 refs., 5 figs., 5 tabs.

Heising, C.D.; Lopes de Oliveira, V. [Iowa State Univ., Ames, IA (United States)

1995-02-01

69

Partitioning of potassium between silicates and sulphide melts: Experiements relevant to the earth's core  

NASA Technical Reports Server (NTRS)

The partitioning of potassium between roedderite, K2Mg5Si12O30 and an Fe-FeS melt was investigaged at temperatures about 40 C above the Fe-FeS eutectic. Roedderite was considered a prime candidate for one of the potassium-bearing phases in the primitive earth because roedderite and merrihueite are the only two silicates containing essential potassium which have been identified in stony meteorites. A mean K2S/FeS weight ratio of (3.340 + or - 0.015) x 0.001 was determined in these experiments; a K2S/FeS weight ratio of about 0.01 would be sufficient to extract all potassium in a chondritic earth into the core. Application of these results to a primitive chondritic earth is discussed and it is concluded that extraction of most of the earth's potassium into the Fe-FeS core would occur under the conditions in the early earth.

Goettel, K. A.

1972-01-01

70

Melting Scenario of the Two-Dimensional Core-Softened System: First-Order or Continuous Transition?  

NASA Astrophysics Data System (ADS)

We present a computer simulation study of the phase behavior of two-dimensional classical particles repelling each other through an isotropic core-softened potential. As in the analogous three dimensional case, a reentrant-melting transition occurs upon compression for not too high pressures. However, in two dimensions in the low density part of the phase diagram melting is a continuous two-stage transition, with an intermediate hexatic phase. All available evidence supports the Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) scenario for this melting transition. On the other hand, at high density part of the phase diagram one first-order transition takes place. We expect that such a phenomenology can be checked in confined monolayers of charge-stabilized colloids with a softened core and water confined between two hydrophobic plates.

Dudalov, D. E.; Fomin, Yu D.; Tsiok, E. N.; Ryzhov, V. N.

2014-05-01

71

Melt seepage and plugging in an ex-vessel core-retention device composed of magnesia bricks  

SciTech Connect

A magnesia brick crucible, used as an ex-vessel core retention device, has been proposed for floating nuclear plants. The refractory brick concept has also been suggested for LMFBR plants, including Clinch River. The purpose of an ex-vessel core retention device is to prevent core-concrete interactions following a core melt accident. One disadvantage of the brick crucible concept is the design requirement for some spacing between bricks to allow for thermal expansion. Cracks resulting from thermal stress or mechanical damage will also be present. Both types of channels introduce a major failure mode. Penetration of the channels by melt could initiate catastrophic and rapid failure of the crucible by eroding the interlocking network and freeing bricks to float away. PLUGM, a coupled, thermal-hydraulic, computer model, answers questions concerning melt seepage and plugging in a cold channel. This paper also describes a series of experiments in which high-temperature steel and oxide melts are poured onto Harklase magnesia bricks. The experiments are designed to validate PLUGM predictions using prototypic materials.

Pilch, M.; Fish, J.

1983-01-01

72

Stability and melting of Fe3C at high pressure and temperature: Implication for the carbon in the Earth's core  

NASA Astrophysics Data System (ADS)

The Earth's core is regarded as an Fe-Ni alloy but its density is lower than that of pure Fe at the core conditions. Therefore, the Earth's core is supposed to contain light elements and carbon is one of the candidates of the light elements to explain the density deficit of the Earth's core. Nakajima et al. (2009) reported the melting temperature of Fe3C up to around 30 GPa based on textual observations, the chemical analysis of the quenched run products and in situ X-ray diffraction experiments using a Kawai-type multi anvil apparatus. Lord et al. (2009) reported melting temperatures of Fe3C up to 70 GPa, which was determined by the temperature plateau during increasing laser power using a laser-heated diamond anvil cell. They also suggested Fe+Fe7C3 is a stable subsolidus phase. There are obvious discrepancies between the melting curve and the stable subsolidus phase reported by Nakajima et al. (2009) and those reported by Lord et al. (2009). In this study, the melting temperatures of Fe3C and a subsolidus phase relation were determined based on in situ X-ray diffraction experiments. This study aims to reveal the stability field of Fe3C and the melting temperature of Fe3C and to discuss the behaviors of carbon in the Earth's core. We have performed experiments using a laser-heated diamond anvil cell combined with in situ X-ray diffraction experiment at BL10XU beamline, SPring-8 synchrotron facility. An NaCl powder and a rhenium or tungsten foil were used for the insulator and gasket, respectively. Melting of the sample was determined by disappearance of the X-ray diffraction peaks. We determined the melting relation of Fe3C up to 145 GPa by in situ X-ray diffraction experiments. Present results are close to Nakajima et al. (2009) up to 30 GPa but become close to that reported by Lord et al. (2009) at higher pressure conditions. The solidus temperature extrapolated to the ICB pressure, 330 GPa, is 5400 K. We also confirmed that Fe3C is stable as a subsolidus phase at least up to 237 GPa and 4100 K. This strongly suggests that Fe3C is a potential candidate of the Earth's inner core although we need further studies at the inner core conditions.

Takahashi, S.; Ohtani, E.; Sakai, T.; Hirao, N.; Ohishi, Y.

2012-12-01

73

The melting temperature of iron hydride at high pressures and its implications for the temperature of the Earth's core  

NASA Astrophysics Data System (ADS)

The Earth's core is about 10% less dense than pure iron under the relevant pressure and temperature conditions, so elements lighter than iron should exist in it. Recent experiments support the hypothesis that hydrogen dominates this light component. The hydrogen dissolved in metallic iron has a large potential to reduce its melting temperature. To estimate the melting temperature of the iron-hydrogen core, experiments were carried out at pressures up to 10 GPa by means of a new technique to determine the melting temperature and chemical composition from the textures of rapidly decompressed iron hydride grains. The rate of reduction of the melting temperature induced by adding hydrogen to iron was obtained as 0953-8984/10/49/052/img1 per unit mole fraction. If this behaviour of hydrogen persists to the much higher pressure deep inside the Earth, the isentrope in the iron-hydrogen core is about 600 K lower than the previous estimates based on experiments on the iron-sulphur-oxygen system.

Okuchi, Takuo

1998-12-01

74

Numerical and Experimental Model Studies on Thermal Hydraulic Behavior of FBR Internal Core Catcher Assembly  

Microsoft Academic Search

Core Catcher is provided as an in-vessel core debris retention device to collect, support, cool and maintain in sub-critical configuration, the generated core debris from fuel melting due to certain postulated Beyond Design Basis Events (BDBE) for Fast Breeder Reactor (FBR). This also acts as a barrier to prevent settling of debris on main vessel and keeps its maximum temperature

Sanjay Kumar Das; Anil Kumar Sharma; A. Jasmin Sudha; G. Punitha; G. Lydia; P. A. Somayajulu; S. S. Murthy; B. Malarvizhi; V. Gopalakrishnan; J. Harvey; N. Kasinathan; M. Rajan

2006-01-01

75

Aluminum/uranium fuel foaming/recriticality considerations for production reactor core-melt accidents  

SciTech Connect

Severe accident studies for the Savannah River production reactors indicate that if coherent fuel melting and relocation occur in the absence of target melting, in-vessel recriticality may be achieved. In this paper, fuel-melt/target interaction potential is assessed where fission gas-induced fuel foaming and melt attack on target material are evaluated and compared with available data. Models are developed to characterize foams for irradiated aluminum-based fuel. Predictions indicate transient foaming, the extent of which is governed by fission gas inventory, heating transient conditions, and bubble coalescence behavior. The model also indicates that metallic foams are basically unstable and will collapse, which largely depends on film tenacity and melt viscosity considerations. For high-burnup fuel, extensive foaming lasting tens of seconds is predicted, allowing molten fuel to contact and cause melt ablation of concentric targets. For low-burnup fuel, contact can not be assured. 9 refs., 4 figs., 4 tabs.

Hyder, M.L.; Ellison, P.G. (Westinghouse Savannah River Co., Aiken, SC (USA)); Cronenberg, A.W. (Engineering Science and Analysis, Albuquerque, NM (USA))

1990-01-01

76

Ab initio melting curve of Fe and Fe-S alloys at extreme pressures: implications for Earth's and exoplanets' cores  

NASA Astrophysics Data System (ADS)

Exoplanets with masses similar to that of Earth have recently been discovered in extrasolar systems [1]. A first order question for understanding their dynamics is to know whether they possess Earth like liquid metallic cores. However, the iron melting curve is unknown at conditions corresponding to planets of several times the Earth's mass (over 15 Mbar for planets with 10 times the Earth's mass [2]). In the density-temperature region of the cores of those super-Earths, we calculate the iron melting curve using first principle molecular dynamics simulations based on density functional theory. We also propose an equation of state for iron in this pressure range. Finally we show the melting curve of Fe3S and discuss the effects of the addition of sulfur to the melting curve of pure iron. [4pt] [1] J. P. Beaulieu, D. P. Bennett, P. Fouque et al., Nature 439 (7075), 437 (2006).[0pt] [2] D. Valencia, R. J. O'Connell, and D. Sasselov, Icarus 181, 545 (2006).

Bouchet, Johann; Morard, Guillaume; Mazevet, Stephane; Guyot, Francois

2011-03-01

77

A postulate to assess ‘habitability’  

NASA Astrophysics Data System (ADS)

One principal challenge in biology is defining a postulate by which the habitability of other planets can be assessed. Current assessments suffer from two potential weaknesses. With respect to other planets, either assumptions are made about the physical and chemical conditions of environments that err on the side of biological optimism without empirical constraint by spacecraft observations or novel physiologies of microorganisms are invented to fit extraterrestrial environmental conditions with no demonstrated microbiological counterparts on Earth. Attempts to assess the habitability of the early Earth suffer from similar problems. We discuss the following postulate: ‘the proposition that a planet is or was habitable requires that the physiological requirements of microorganisms on Earth known at the time of assessment match the empirically determined combined physical and chemical conditions in the extraterrestrial or early Earth environment being assessed’ as a means of evaluating ‘habitability’. We use as tests for our postulate the early Earth and the cloud deck of Venus (a habitat that has been a source of optimistic debate for forty years). We conclude that, although the early Earth was habitable, Venus is a dead world.

Cockell, Charles S.; Westall, Frances

2004-04-01

78

A1-U fuel foaming/recriticality considerations for production reactor core-melt accidents  

SciTech Connect

Severe accident studies for the Savannah River production reactors indicate that if coherent fuel melting and relocation occur in the absence of target melting, in-vessel recriticality may be achieved. In this paper, fuel-melt/target interaction potential is assessed, where fission gas-induced fuel foaming and melt attach on target material are evaluated and compared with available data. Models are developed to characterize foams for irradiated Al-based fuel. Predictions indicate transient foaming (the extent of which is governed by fission gas inventory), heating transient, and bubble coalescence behavior. The model also indicates that metallic foams are basically unstable and will collapse, which largely depends on film tenacity and melt viscosity. For high-burnup fuel, foams lasting tens of seconds are predicted, allowing molten fuel to contact and cause melt ablation of concentric targets. For low-burnup fuel, contact can not be assured, thus recriticality may be of concern at reactor startup. 8 refs., 4 figs., 4 tabs.

Cronenberg, A.W. (Engineering Science and Analysis, Albuquerque, NM (USA)); Hyder, M.L.; Ellison, P.G. (Westinghouse Savannah River Co., Aiken, SC (USA))

1990-01-01

79

Melting and refreezing beneath Roi Baudouin Ice Shelf (East Antarctica) inferred from radar, GPS, and ice core data  

NASA Astrophysics Data System (ADS)

Ice-penetrating radar profiles across the grounding line of a small ice-rise promontory located within the Roi Baudouin Ice Shelf in the Dronning Maud Land sector of East Antarctica show downward dipping englacial radar-detected reflectors. Model results indicate that this reflector pattern is best fit by including basal melting of at least 15 cm a-1. This rate of melting is low compared with rates observed on larger ice shelves in both West and East Antarctica. Ice cores extracted from a rift system close to the ice-rise promontory show several meters of marine ice accreted beneath the shelf. These observations of low rates of basal melting, and limited distribution of accreted marine ice suggest that either Antarctic surface water may reach the ice shelf base or that circulation beneath the shelf is likely dominated by the production of high salinity shelf water rather than the incursion of circumpolar deep water, implying a weak sub-shelf circulation system here. Many of the ice shelves located along the coast of Dronning Maud Land are, like Roi Baudouin Ice Shelf, characterized by frequent ice rises and promontories. Therefore, it is highly likely that these are also of shallow bathymetry and are subject to similarly weak side-shelf basal melting and refreezing.

Pattyn, F.; Matsuoka, K.; Callens, D.; Conway, H.; Depoorter, M.; Docquier, D.; Hubbard, B.; Samyn, D.; Tison, J. L.

2012-12-01

80

Rapid, dynamic segregation of core forming melts: Results from in-situ High Pressure- High Temperature X-ray Tomography  

NASA Astrophysics Data System (ADS)

The timing and mechanisms of core formation in the Earth, as well as in Earth-forming planetesimals is a problem of significant importance in our understanding of the early evolution of terrestrial planets . W-Hf isotopic signatures in meteorites indicate that core formation in small pre-differentiated planetesimals was relatively rapid, and occurred over the span of a few million years. This time scale is difficult to achieve by percolative flow of the metallic phase through a silicate matrix in textural equilibrium. It has been suggested that during this active time in the early solar system, dynamic processes such as impacts may have caused significant deformation in the differentiating planetesimals, which could lead to much higher permeability of the core forming melts. Here, we have measured the change in permeability of core forming melts in a silicate matrix due to deformation. Mixtures of San Carlos olivine and FeS close to the equilibrium percolation threshold (~5 vol%FeS) were pre-synthesized to achieve an equilibrium microstructure, and then loaded into the rotational Drickamer apparatus at GSE-CARS, sector 13-BMD, at the Advanced Photon Source (Argonne National Laboratory). The samples were subsequently pressed to ~2GPa, and heated to 1100°C. Alternating cycles of rotation to collect X-ray tomography images, and twisting to deform the sample were conducted until the sample had been twisted by 1080°. Qualitative and quantitative analyses were performed on the resulting 3-dimensional x-ray tomographic images to evaluate the effect of shear deformation on permeability and migration velocity. Lattice-Boltzmann simulations were conducted, and show a marked increase in the permeability with increasing deformation, which would allow for much more rapid core formation in planetesimals.

Watson, H. C.; Yu, T.; Wang, Y.

2011-12-01

81

Melting of Fe-Ni-Si and Fe-Ni-S alloys at megabar pressures: implications for the core-mantle boundary temperature  

NASA Astrophysics Data System (ADS)

High pressure melting behavior of three Fe-alloys containing 5 wt% Ni and (1) 10 wt% Si, (2) 15 wt% Si or (3) 12 wt% S was investigated up to megabar pressures by in situ X-ray diffraction and laser-heated diamond anvil cell techniques. We observe a decrease in melting temperature with increasing Si content over the entire investigated pressure range. This trend is used to discuss the melting curve of pure Fe. Moreover, our measurements of eutectic melting in the Fe-Fe3S system show a change in slope around 50 GPa concomitant with the fcc-hcp phase transition in pure solid iron. Extrapolations of our melting curve up to the core-mantle boundary pressure yield values of 3,600-3,750 K for the freezing temperature of plausible outer core compositions.

Morard, Guillaume; Andrault, Denis; Guignot, Nicolas; Siebert, Julien; Garbarino, Gaston; Antonangeli, Daniele

2011-12-01

82

Statistical Distribution of Leucocratic Melts in the Swakane Terrane, North Cascades Crystalline Core, WA: Implications for Melt Transport and Collection in Deep Crust  

NASA Astrophysics Data System (ADS)

It has been proposed that melt collection and transport in the crust is controlled by low stress pathways influenced by anisotropy, including foliation or bedding, and/or by active deformation represented by local or regional folding, shearing, and boudinage. We examine this idea in the Swakane quartz biotite gneiss (SBG), Cascades core, Washington. The SBG is the deepest exposed section in this Cretaceous to Paleogene magmatic arc. Published pressures of 10-12 kbar in the SBG, indicate that > 40 km of exhumation have occurred since peak metamorphism (Valley et al., 2000). The SBG displays a strong, pervasive foliation, both regional and local folding, and pervasive shearing. A conjugate set of ~68 Ma leucocratic intrusions in the SBG are composed of quartz + plagioclase + muscovite + garnet + biotite. They have large length to width aspect ratios, in many cases are less than 15 cm thick, and because of their composition and shapes are interpreted to be locally derived and locally transported melts of the SBG. During melt transport and collection, the entire unit was undergoing exhumation by SW-NE contraction, and arc-oblique, top-to-the-north shear. Preliminary observations indicate that prior to deformation most of the veins in the Columbia River area formed a conjugate set with the dominant set of veins parallel to foliation. However, numerous examples exist where veins maintain a consistent orientation independent of all structures. The acute intersection of these veins indicates that ? 1 is sub-horizontal, and approximately SW-NE, and ? 3 is vertical. Outcrops in Tamarack Creek, which represent a slightly shallower part of the SBG, show a similar pattern of conjugate veins, but here neither set of veins is parallel to foliation. This stress field is consistent with the regional stress field for SW-NE contraction in the NCCC. In both locations, veins injected at an angle to foliation are more deformed suggesting that deformation was still active as intrusion continued. We suggest that the orientation of leucocratic veins in the Swakane was a result of the regional stress field, and relatively independent of all host rock structures.

Boysun, M. A.; Paterson, S. R.

2001-12-01

83

Rapid Detection of KIT Mutations in Core-Binding Factor Acute Myeloid Leukemia Using High-Resolution Melting Analysis  

PubMed Central

The most frequent KIT mutations reported in core-binding factor acute myeloid leukemia are point mutations and insertions/deletions in exons 17 and 8. The vast majority of KIT mutation detection procedures are time-consuming, costly, or with a high lower limit of detection. High-resolution melting (HRM) is a gene scanning method that combines simplicity and rapid identification of genetic variants. We describe an HRM method for the simultaneous screening of exons 8 and 17 KIT mutations and report the results obtained in 69 core-binding factor acute myeloid leukemia patients. Mutation detection was compared with sequencing as the gold standard. The HRM method used high-resolution melting master reagents (Roche) and the LightCycler 480 (Roche) platform. HRM was reproducible, showed a lower limit of detection of 1%, and discriminated all patients with mutated KIT from controls without false positive or false negative results. Additionally, most of the mutations were differentiated from the other mutations. KIT mutations were present in 15.9% of patients, showing a higher incidence in inv(16) (25.8%) than in t(8;21) (7.9%). The presence of a KIT mutation was associated with a high white blood cell count, and adult patients with an exon 17 mutation had a higher incidence of relapse. These findings verify that HRM is a reliable, rapid, and sensitive method for KIT mutation screening. Furthermore, our study corroborates the unfavorable prognosis associated with exon 17 KIT mutations.

Fuster, Oscar; Barragan, Eva; Bolufer, Pascual; Cervera, Jose; Larrayoz, Maria Jose; Jimenez-Velasco, Antonio; Martinez-Lopez, Joaquin; Valencia, Ana; Moscardo, Federico; Sanz, Miguel Angel

2009-01-01

84

Creep rupture behavior of a PWR lower head in a core-melt accident  

SciTech Connect

Although the Three Mile Island unit 2 (TMI-2) vessel did not fail, code analyses in support of the Organization for Economic Cooperation and Development/Nuclear Energy Agency TMI-2 Vessel Investigation Project generally predicted creep rupture for these conditions. This fueled speculation that there might be some inherent mechanism not previously recognized that could delay or prevent lower head failure. The most widely held belief is that the relocated melt did not adhere to the lower head; consequently, there should be gaps between the inside surface of the vessel and the relocated melt. These gaps, perhaps widened by temperature-induced creep of the lower head, provide a channel for water intrusion and subsequent quenching of the head, preventing its creep rupture. Therefore, from both accident assessment and accident mitigation considerations, there is a need to understand the mechanism of lower head creep and rupture.

Jeong, Kwang Jin; Lim, Dong Cheol; Hwang, Il Soon [Seoul National Univ. (Korea, Republic of)

1997-12-01

85

Solubility of palladium in silicate melts: Implications for core formation in the Earth  

Microsoft Academic Search

Palladium solubilities in silicate melts of anorthite-diopside-eutectic composition were determined at a wide range of oxygen fugacities, from pure O 2 to f o2 slightly below the iron-wüstite buffer and at temperatures ranging from 1343 to 1472°C. Experiments were performed by heating palladiumloops with silicates inside a gas controlled furnace. Palladium concentrations were determined by neutron activation analysis. Repeated analyses

A. Borisov; H. Palme; B. Spettel

1994-01-01

86

Evidence for Past Melting at the Base of the GISP2 Ice Core from Uranium-Thorium Disequilibrium Measurements  

NASA Astrophysics Data System (ADS)

We measured 238U-234U-230Th disequilibria by mass spectrometric methods for silty ice samples from the base of the GISP2 Greenland ice core, at a depth of 3040-3052 m. The expected age of these samples is >150 kyr based on counting ice layers. We separated the samples into several fractions by filtration and analyzed the <50 nm (truly dissolved + particulate) and >200 nm (particulate) filtered fractions. In the <50 nm fractions, low Th/U mass ratios of 0.51-0.65 indicate that a large portion (86-89%) of U is truly dissolved and not associated with particles. In addition, 230Th/234U activity ratios are quite low (0.18-0.24), suggesting either recent 230Th loss and/or 234U addition to the samples. This Th/U fractionation is not consistent with an age >150 kyr. Since liquid water is characterized by 230Th/234U activity ratios <<1, these results suggest that recent melting/freezing event(s) have occurred at the base of the GISP2 core. The particulate (>200 nm) fraction is characterized by Th/U ratios of ~4.4-4.9, 234U/238U activity ratios of 1.049-1.056, and 230Th/234U activity ratios of 1.12-1.23. The U-Th disequilibrium in the particles is consistent with recent (<350 kyr) fractionation of U-Th in these ice samples. We have modeled these results using a two component mass balance calculation, with dissolved and particulate pools for each radionuclide. The main assumption is that all of the 232Th in the <50 nm fraction is due to particles, due to the low aqueous solubility of 232Th. By mass balance, 230Th/234U activity ratios for the truly dissolved fraction are 0.031-0.062, and dates for when the samples were last frozen are 3.5-6.9 kyr. These results are consistent with the notion of ice melting at the base of large continental ice sheets, with recent evidence of large sub-glacial lakes in Antarctica and active melting at the base of the nearby N-GRIP Greenland ice core. There also appears to be a significant difference in age for the deepest ice sample (3.5 kyr; 3052 m) and the other samples (5.2-6.9 kyr; 3040-3048 m), suggesting that the deepest part of the ice core adjacent to bedrock at 3053.3 m depth may have existed as liquid water for at least several hundred - few thousand years.

Goldstein, S. J.; Lee, V. E.; Nishiizumi, K.; Murrell, M. T.; Amato, R. S.; Nunn, A. J.

2011-12-01

87

Footwall Structure of Oceanic Core Complexes: New Insights from Geophysical Data for Footwall Capture of Ascending Melt  

NASA Astrophysics Data System (ADS)

Oceanic core complexes (OCCs) are the footwalls of long-lived detachment faults which form in response to magma-poor crustal accretion processes along the mid-ocean ridge. Although OCC formation is expected to occur at intermediate levels of melt supply to the ridge axis (e.g. Buck et al., 2005), sidescan sonar data have shown that surficial volcanism is absent during part of the OCC life cycle (MacLeod et al., 2009). This implies that footwall capture of ascending melt is an active process during OCC formation. Here, we present the results of a shipboard gravity and deep-towed magnetic survey across actively forming OCCs on the Mid-Atlantic Ridge between 12-14°N. Forward modelling of magnetic data show that the oldest parts of OCCs generally have zero magnetisation, and thus we interpret these areas as comprising non- or low-magnetic upper crustal material such as sheeted dikes and gabbros. In contrast, the younger, domal sections of OCCs often record a very heterogeneous magnetisation pattern, indicative of significant local variations in footwall magnetisation and/or composition over distances of < 6 km (our track spacing). Furthermore, 2.5D and 3D modelling of gravity data reveal a zone of relatively low density material within the ultramafic footwalls of near-axis OCCs. For a density of 2900 kg/m^3, this low density zone (LDZ) must extend for ~3-4 km beneath the seafloor. We interpret this LDZ as comprising a mixture (based on magnetic results) of serpentinised peridotite and gabbroic material that has accreted within the OCC footwall as the detachment fault has captured ascending melt beneath the ridge axis. Older near-axis OCCs in the region are generally associated with a thicker LDZ, which most likely represents more pervasive serpentinisation and melt accumulation with age. References: Buck, W. R., L. L. Lavier & A. N. B. Poliakov, 2005. Modes of faulting at mid-ocean ridges, Nature, 434, 719-723. MacLeod, C. J., R. C. Searle, B. J. Murton, J. F. Casey, C. Mallows, S. C. Unsworth, K. L. Achenbach & M. Harris, 2009. Life cycle of oceanic core complexes, Earth and Planetary Science Letters, 287, 333-344.

Mallows, C.; Searle, R. C.

2010-12-01

88

High Pressure Melting of Iron with Nonmetals Sulfur, Carbon, Oxygen, and Hydrogen: Implications for Planetary Cores  

NASA Astrophysics Data System (ADS)

The earth's core consists of a solid metallic center surrounded by a liquid metallic outer layer. Understanding the compositions of the inner and outer cores allows us to better understand the dynamics of the earth's core, as well as the dynamics of the cores of other terrestrial planets and moons. The density and size of the earth's core indicate that it is approximately 90% metallic, predominantly iron, with about 10% light elements. Iron meteorites, believed to be the remnants of planetary cores, provide further constraints on the composition of the earth's core, indicating a composition of 86% iron, 4% nickel, and 10% light elements. Any potential candidate for the major light element core component must meet two criteria: first, it must have high cosmic abundances and second, it must be compatible with Fe. Given these two constraints there are five plausible elements that could be the major light element in the core: H, O, C, S, and Si. Of these five possible candidates this thesis focuses on S and C as well exploring the effect of minor amounts of O and H on the eutectic temperature in a Fe-FeS core. We look at two specific aspects of the Fe-FeS system: first, the shape of the liquidus as a function of pressure, second, a possible cause for the reported variations in the eutectic temperature, which draws on the effect of H and O. Finally we look at the effect of S and C on partitioning behavior of Ni, Pt, Re,Co, Os and W between cohenite and metallic liquid. We are interested in constraining the shape of the Fe-FeS liquidus because as a planet with a S-enriched core cools, the thermal and compositional evolution of its core is constrained by this liquidus. In Chapter 1 I present an equation that allows for calculation of the temperature along the liquidus as a function of pressure and composition for Fe-rich compositions and pressures from 1 bar to 10 GPa. One particularly interesting feature of the Fe --rich side of the Fe-FeS eutectic is the sigmoidal shape of the liquidus. This morphology indicates non-ideal liquid solution behavior and suggests the presence of a metastable solvus beneath the liquidus. An important consequence of such curved liquidi is that isobaric, uniform cooling requires substantial variations in the solidification rate of the core. Additionally, in bodies large enough for P variation within the core to be significant, solidification behavior is further complicated by the P dependence of the liquidus shape. Brett and Bell (1969) show that at 3 GPa, the liquidus curvature relaxes, implying that the liquid solution becomes more ideal. By 10 GPa, the liquidus approaches nearly ideal behavior (Chen et al., 2008b). However, at 14 GPa, the liquidus again assumes a sigmoidal curvature (Chen et al., 2008a; Chen et al., 2008b), suggesting a fundamental change in the thermodynamic behavior of the liquid. Chapter 1 of this thesis accounts for the observed complexity in the liquidus up to 10 GPa thus enabling more accurate modeling of the evolution of the cores of small planets (Buono and Walker, 2011). Accurately knowing the eutectic temperature for the Fe-FeS system is important because it places a minimum bound on the temperature of a S-enriched core that has a solid and liquid component which are in equilibrium. Unfortunately literature values for the 1 bar to 10 GPa eutectic temperature in the Fe-FeS system are highly variable making the estimation of core temperature, an important geodynamic parameter, very difficult. In Chapter 2 we look at a possible cause of this observed variation by experimentally investigating the effects of H on the eutectic temperature in the Fe-FeS system at 6 and 8 GPa. We find that H causes a decrease in the eutectic temperature (but that O does not) and that this decrease can explain some of the observed scatter in the available data. The effect of H on the eutectic temperature increases with increasing pressure (i.e. the eutectic temperature is more depressed at higher pressures), matching the trend reported for the Fe-FeS system (Fei et al., 1997). Our work suggests

Buono, Antonio Salvatore

89

Modelling micro-level volume expansion during reactive melt infiltration using non-isothermal unreacted-shrinking core models  

NASA Astrophysics Data System (ADS)

Reactive melt infiltration is a process used to manufacture silicon carbide fibre-reinforced silicon carbide (SiC/SiC) composites. The present stage of research on reactive infiltration is primarily experimental, wherein complete infiltration is rarely achieved and unreacted silicon still remains in the composite. This paper deals with the micro-modelling aspect of reactive melt infiltration and estimates volume expansion due to mass transfer and reaction for cylindrical fibres. The thickness of the reaction product layer forming the matrix in the composite is determined by using an unreacted-shrinking core (URSC) model for cylindrical geometry in terms of physical parameters (diffusivity of the reactants and temperature) and non-dimensional physical quantities (such as the Sherwood number, Nusselt number and Thiele modulus). The effectiveness factors for the chemical reaction are determined as a function of time for various sets of physical parameters. The amount of volume expansion is found by determining the growth of the radius of the reaction product layer. It is concluded that lower initial temperatures of the solid reactant and higher ratios of heat capacity of reaction product to heat of reaction are favourable for infiltration. Determining the volume expansion in a single particle will later help in determining the transient permeability in a fibre preform during infiltration and also in optimizing this process.

Rajesh, G.; Bhagat, R. B.

1998-11-01

90

Silicate glasses and sulfide melts in the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure, Virginia, USA  

USGS Publications Warehouse

Optical and electron-beam petrography of melt-rich suevite and melt-rock clasts from selected samples from the Eyreville B core, Chesapeake Bay impact structure, reveal a variety of silicate glasses and coexisting sulfur-rich melts, now quenched to various sulfi de minerals (??iron). The glasses show a wide variety of textures, fl ow banding, compositions, devitrifi cation, and hydration states. Electron-microprobe analyses yield a compositional range of glasses from high SiO2 (>90 wt%) through a range of lower SiO2 (55-75 wt%) with no relationship to depth of sample. Some samples show spherical globules of different composition with sharp menisci, suggesting immiscibility at the time of quenching. Isotropic globules of higher interfacial tension glass (64 wt% SiO2) are in sharp contact with lower-surface-tension, high-silica glass (95 wt% SiO2). Immiscible glass-pair composition relationships show that the immiscibility is not stable and probably represents incomplete mixing. Devitrifi cation varies and some low-silica, high-iron glasses appear to have formed Fe-rich smectite; other glass compositions have formed rapid quench textures of corundum, orthopyroxene, clinopyroxene, magnetite, K-feldspar, plagioclase, chrome-spinel, and hercynite. Hydration (H2O by difference) varies from ~10 wt% to essentially anhydrous; high-SiO2 glasses tend to contain less H2O. Petrographic relationships show decomposition of pyrite and melting of pyrrhotite through the transformation series; pyrite? pyrrhotite? troilite??? iron. Spheres (~1 to ~50 ??m) of quenched immiscible sulfi de melt in silicate glass show a range of compositions and include phases such as pentlandite, chalcopyrite, Ni-As, monosulfi de solid solution, troilite, and rare Ni-Fe. Other sulfi de spheres contain small blebs of pure iron and exhibit a continuum with increasing iron content to spheres that consist of pure iron with small, remnant blebs of Fe-sulfi de. The Ni-rich sulfi de phases can be explained by melting and/or concentrating targetderived Ni without requiring an asteroid impactor source component. The presence of locally unaltered glasses in these rocks suggests that in some rock volumes, isolation from postimpact hydrothermal systems was suffi cient for glass preservation. Pressure and temperature indicators suggest that, on a thin-section scale, the suevites record rapid mixing and accumulation of particles that sustained widely different peak temperatures, from clasts that never exceeded 300 ?? 50 ??C, to the bulk of the glasses where melted sulfi de and unmelted monazite suggest temperatures of 1500 ?? 200 ??C. The presence of coesite in some glass-bearing samples suggests that pressures exceeded ~3 GPa. ?? 2009 Geological Society of America.

Belkin, H. E.; Horton, Jr. , J. W.

2009-01-01

91

Molecular dynamics simulations on the melting, crystallization, and energetic reaction behaviors of Al/Cu core-shell nanoparticles  

NASA Astrophysics Data System (ADS)

Using molecular dynamics simulations combined with the embedded atom method potential, we investigate the heating, cooling, and energetic reacting of core-shell structured Al-Cu nanoparticles. The thermodynamic properties and structure evolution during continuous heating and cooling processes are also investigated through the characterization of the total potential energy distribution, mean-square-distance and radial distribution function. Some behaviors related to nanometer scale Cu/Al functional particles are derived that two-way diffusion of Al and Cu atoms, glass phase formation for the fast cooling rate, and the crystal phase formation for the low cooling rate. Two-way atomic diffusion occurs first and causes the melting and alloying. In the final alloying structure, Cu and Al atoms mixed very well except for the outmost shell which has more Al atoms. For the investigation of the thermal stability and energetic reaction properties, our study show that a localized alloying reaction between the Al core and Cu shell is very slow when the initial temperature is lower than 600 K. But a two-stage reaction may occur when the initial temperature is 700 K. The reaction rate is determined by the solid-state diffusion of Al atoms in the Cu shell at the first stage, yet the reaction rate is much faster at the second stage, due to the alloying reaction between the liquid Al core and the Cu shell. At higher temperatures such as 800 K and 900 K, the alloying reaction occurs directly between the liquid Al core and the Cu shell.

Cheng, Xin-Lu; Zhang, Jin-Ping; Zhang, Hong; Zhao, Feng

2013-08-01

92

Enhanced Ex-Vessel Analysis for Fukushima Daiichi Unit 1: Melt Spreading and Core-Concrete Interaction Analyses with MELTSPREAD and CORQUENCH.  

National Technical Information Service (NTIS)

System-level code analyses by both United States and international researchers predict major core melting, bottom head failure, and corium-concrete interaction for Fukushima Daiichi Unit 1. Although system codes such as MELCOR and MAAP are capable of capt...

K. R. Robb M. W. Francis

2013-01-01

93

Melting relationships of the Fe-S-Si system up to 60 GPa: Implications for the thermal structure of the Earth's core  

NASA Astrophysics Data System (ADS)

The Earth's core is mainly composed of iron alloy, however the lighter elements are required in the core to account for the core density deficit (Birch, 1964). The potential light elements have been considered to be S, Si, O, C, and H (Poirier, 1994). Alloying light elements significantly affects the physical properties of iron and depresses its melting temperature(e.g., Boehler, 1996b). Sulfur and silicon are considered as major light element components based on cosmochemical study (McDonough, 2003) and high pressure partitioning experiments (e.g., Sakai et al., 2006), therefore the melting relationship of the Fe-S-Si system is the key information to clarify the thermal and compositional structure of the Earth's core. Many melting experiments of Fe-light elements alloys have been performed under high pressure corresponding Earth's core using diamond anvil cell. However in the case of the Fe-S-Si ternary system, there are no experimental data at high pressure and the phase and melting relations have not been clarified in detail under core conditions. In this study, the phase relationships and the solidus temperature of the Fe-S-Si system were determined up to 60 GPa using a laser-heated diamond anvil cell combined with in situ X-ray diffraction technique. The sample composition used for this study were Fe80.1S12.7Si7.2(Fe-8wt.%S-4wt.%Si) and Fe74.4S18.5Si7.1(Fe-12wt.%S-4wt.%Si), which are in the range of the amounts of the light elements to explain the density deficit in the Earth's core (Chen et al., 2007). In situ X-ray diffraction experiments were conducted at the BL10XU beamline at the SPring-8 facility (Ohishi et al., 2008). On the basis of diffraction patterns, Fe(hcp/fcc) which contains silicon and Fe3S are stable phases under subsolidus conditions. First Fe3S phase melts at the solidus temperature, and Fe-Si alloy coexists with partial melts above the eutectic temperature in this system. This melting sequence is consistent with the study of the Fe-Fe3S system observed earlier by Kamada et al. (2010). The solidus temperature is significantly lower than the melting temperature of pure Fe (Ma et al., 2004) and close to the eutectic point of the Fe-Fe3S system (Morard et al., 2008), suggesting that the effect of 7.2 at.% silicon on the eutectic temperature in the Fe-Fe3S system is minor. In order to draw the solidus curve as a function of pressure, we fitted the present results using the Simon's law. The obtained fitting parameters are a=104(16) and c=0.88(1). Based on our results of the melting relationship, the temperature at the core-mantle boundary should be greater than 2900(200) K and the temperature at the boundary of the inner and outer cores is estimated to be 5680(350) K, assuming that sulfur and silicon are the light elements in the Earth's core. The results in this study provide important constraints on the thermal structure of the Earth's core.

Sakairi, T.; Ohtani, E.; Sakai, T.; Kamada, S.; Miyahara, M.; Hirao, N.; Ohishi, Y.

2012-12-01

94

Deformation-induced metal melt networks in silicates: Implications for core–mantle interactions in planetary bodies  

Microsoft Academic Search

Previous analyses of texturally equilibrated, hydrostatically annealed olivine rocks containing metal and metal–sulfide melts have determined that these melts do not form interconnected networks at low volume fractions. To characterize the change in connectivity of metal melt in response to deformation, we used optical microscopy and electron microprobe analyses to investigate the microstructures of samples of olivine+gold sheared to shear

Nathan Groebner; David L. Kohlstedt

2006-01-01

95

Stability and melting relations of Fe3C up to 3 Mbar: Implication for the carbon in the Earth's inner core  

NASA Astrophysics Data System (ADS)

The Earth's core is regarded as an Fe-Ni alloy but its density is lower than that of pure Fe at the core conditions. Therefore, the Earth's core is supposed to contain light elements and carbon is one of the candidates of the light elements to explain the density deficit of the Earth's core. Nakajima et al. (2009) reported the melting temperature of Fe3C up to around 30 GPa based on textual observations, the chemical analysis of the quenched run products and in situ X-ray diffraction experiments using a Kawai-type multi anvil apparatus. Lord et al. (2009) reported melting temperatures of Fe3C up to 70 GPa, which was determined by the temperature plateau during increasing laser power using a laser-heated diamond anvil cell. They also suggested Fe+Fe7C3 is a stable subsolidus phase. There are obvious discrepancies between the melting curve and the stable subsolidus phase reported by Nakajima et al. (2009) and those reported by Lord et al. (2009). In this study, the melting temperatures of Fe3C and a subsolidus phase relation were determined based on in situ X-ray diffraction experiments and observations of the recovered sample. This study aims to reveal the stability field of Fe3C and the melting temperature of Fe3C and to discuss the behaviors of carbon in the Earth's core. We have performed experiments using a laser-heated diamond anvil cell combined with in situ X-ray diffraction experiment at BL10XU beamline, SPring-8 synchrotron facility. We also conducted quench experiments for observation of the recovered sample at Tohoku University. Synthesized Fe3C or Fe+Fe3C (C = 5.2 wt.%) were sandwiched by NaCl or SiO2 glass layers, which were used as the thermal insulator and the pressure medium. Melting of the sample was determined by disappearance of the X-ray diffraction peaks and textual observations. We determined the melting relation of Fe3C up to 200 GPa by in situ X-ray diffraction experiments and textual observations of recovered samples. The melting temperature extrapolated to the ICB pressure, 330 GPa, is 5100 K. We also confirmed that Fe3C is stable as a subsolidus phase at least up to 340 GPa. This strongly suggests that Fe3C is a potential candidate of the Earth's inner core although we need further studies at the inner core conditions. However, if the core has a carbon-rich composition and the inner core crystalized by cooling of the outer core from above 5100 K, the inner core is indicated to be composed of Fe7C3, initially.

Takahashi, S.; Ohtani, E.; Sakai, T.; Mashino, I.; Kamada, S.; Miyahara, M.; Sakamaki, T.; Hirao, N.; Ohishi, Y.

2013-12-01

96

High Pressure Melting, Phase Diagrams, and Equations of State in the Fe-FeSi System with Application to Earth's Core  

NASA Astrophysics Data System (ADS)

The Earth's core is comprised mostly of iron, with some nickel and several weight percent of one or more light elements. The light element(s) dictate phase relations, structure, and dynamic behaviour, so it is crucial to evaluate various candidates at conditions of planetary interiors. We present results on high P-T phase diagrams and equations of state in the Fe-FeSi system with application to the structure and composition of Earth's core. X-ray diffraction measurements were performed on stoichiometric FeSi and on Fe-Si alloys containing 9 and 16 wt% silicon in a laser-heated diamond anvil cell at the APS, NSLS, and ALS. Pressures were determined from the lattice parameter of KBr. We have investigated the phase diagram of Fe-9Si to 100 GPa and over 3000 K. Our melting curve agrees with previous results on similar alloys [1,2], as demonstrated using multiple methods of detecting melting. Our subsolidus results are similar to those of Lin et al. [3], though we find the B2 structure instead of bcc, and a shallower slope for the hcp+B2 to fcc+B2 boundary. We studied phase relations of Fe-16Si to over 135 GPa, finding agreement with previous melting curves [2,4]. Below 45 GPa, this alloy has the D0_3 structure. At high pressures, Fe-16Si breaks down into a mixture of B2 and hcp phases, with this mixture stable to pressures of the Earth's outer core. This is the first study on the B2 phase of FeSi with in situ X-ray diffraction at high pressures and temperatures. We report a wide B2+B20 two-phase field in FeSi, with complete conversion to the B2 structure by ~42 GPa. A melting experiment on FeSi agrees with the results of Lord et al. [5]. We have synthesized our results with previous studies to construct T-X and P-X phase diagrams, and we have determined thermal equations of state of each alloy. Our measured densities can be used to constrain the maximum amount of silicon in the Earth's outer core by comparison to the equation of state of hcp-Fe [6] and the seismologically-determined density. Assuming a core-mantle boundary (CMB) temperature of 4000 +/- 500 K and a 1-2% density decrease upon melting, the amount of silicon in the outer core required to match PREM at the CMB is 11.3 +/- 1.5 weight percent, under the simplifying assumption of a purely Fe-Ni-Si outer core. The minimum temperature of an Fe-Si outer core is 4380 K, based on the eutectic melting point of Fe-FeSi alloys, and silicon is shown not to significantly depress the melting point of iron at core conditions. At the highest pressures reached, only the hcp and B2 structures are seen in the Fe-FeSi system. We predict that alloys containing more than ~4-8 wt% Si will convert to an hcp+B2 mixture and later to the hcp structure with increasing pressure, and that an iron-silicon alloy in the Earth's inner core would most likely be a mixture of hcp and B2 phases. [1] Kuwayama and Hirose (2004) Am Mineral 89, 273-276 [2] Morard et al. (2011) PCM 38, 767-776 [3] Lin et al (2002) Science 295, 313-315 [4] Asanuma et al. (2010) PCM 37, 353-359 [5] Lord et al. (2010) JGR 115, B06208 [6] Dewaele et al. (2006) PRL 97, 215504

Fischer, R. A.; Campbell, A. J.; Reaman, D. M.; Heinz, D. L.; Dera, P. K.; Prakapenka, V.

2012-12-01

97

Petrography, geochemistry, and 40Ar-39Ar ages of impact melt rocks and breccias from the Ames Impact Structure, Oklahoma: The Nicor Chestnut 18-4 drill core  

NASA Astrophysics Data System (ADS)

The 15-km-diameter Ames structure in northwestern Oklahoma is located 2.75 km below surface in Cambro-Ordovician Arbuckle dolomite, which is overlain by Middle Ordovician Oil Creek Formation shale. The feature is marked by two concentric ring structures, with the inner ring of about 5 km diameter probably representing the collapsed remnant of a structural uplift composed of brecciated Precambrian granite and Arbuckle dolomite. Wells from both the crater rim and the central uplift are oil- and gas-producing, making Ames one of the economically important impact structures. Petrographic, geochemical, and age data were obtained on samples from the Nicor Chestnut 18-4 drill core, off the NW flank of the central uplift. These samples represent the largest and best examples of impact melt breccia obtained so far from the Ames structure. They contain carbonate rocks which, therefore, are derived from the target sequence. The chemical composition of the impact melt breccias is similar to that of target granite, with variable carbonate admixture. Some impact melt rocks are enriched in siderophile elements indicating the possible presence of a meteoritic component. Based on stratigraphic arguments, the age of the crater was estimated at 470 Ma. Previous 40Ar-39Ar dating attempts of impact melt breccias from the Dorothy 1-19 core yielded plateau ages of about 285 Ma, which is in conflict with the stratigraphic age. The new 40Ar-39Ar age data obtained on the melt breccias from the Nicor Chestnut core by UV laser spot analysis, resulted in a range of ages with maxima around 300 Ma. These data could reflect processes related either the regional Nemaha Uplift or resetting due to hot brines active on a midcontinent-wide scale, perhaps in related to the Alleghenian and Ouachita orogenies. The age data indicate an extended burial phase associated with thermal overprint during Late Pennsylvanian-Permian.

Koeberl, Christian; Reimold, Wolf Uwe; Kelley, Simon P.

2001-05-01

98

Black carbon concentrations from a Tibetan Plateau ice core spanning 1843-1982: recent increases due to emissions and glacier melt  

NASA Astrophysics Data System (ADS)

Black carbon (BC) deposited on snow and glacier surfaces can reduce albedo and lead to accelerated melt. An ice core recovered from Guoqu glacier on Mt. Geladaindong and analyzed using a Single Particle Soot Photometer provides the first long-term (1843-1982) record of BC concentrations from the Central Tibetan Plateau. The highest concentrations are observed from 1975-1982, which corresponds to a 2.0-fold and 2.4-fold increase in average and median values, respectively, relative to 1843-1940. BC concentrations post-1940 are also elevated relative to the earlier portion of the record. Causes for the higher BC concentrations include increased regional BC emissions and subsequent deposition, and melt induced enrichment of BC, with the melt potentially accelerated due to the presence of BC at the glacier surface. A qualitative comparison of the BC and Fe (used as a dust proxy) records suggests that if changes in the concentrations of absorbing impurities at the glacier surface have influenced recent glacial melt, the melt may be due to the presence of BC rather than dust. Guoqu glacier has received no net ice accumulation since the 1980s, and is a potential example of a glacier where an increase in the equilibrium line altitude is exposing buried high impurity layers. That BC concentrations in the uppermost layers of the Geladaindong ice core are not substantially higher relative to deeper in the ice core suggests that some of the BC that must have been deposited on Guoqu glacier via wet or dry deposition between 1983 and 2005 has been removed from the surface of the glacier, potentially via supraglacial or englacial meltwater.

Jenkins, M.; Kaspari, S.; Kang, S.; Grigholm, B.; Mayewski, P. A.

2013-10-01

99

Carbon Solubility in Core Melts in Shallow Magma Ocean Environment and its bearing on Distribution of Carbon between Deep Earth Reservoirs  

NASA Astrophysics Data System (ADS)

Carbon affects the melting phase relations of mantle rocks [1] and core metal [2], influences the physical properties of molten silicates and metals, and also has significant effect on partitioning of other key elements between various deep Earth phases. But the carbon budget of Earth's deep mantle and core is poorly constrained due to lack of knowledge of behavior of carbon during core formation. In order to determine the storage capacity of dissolved carbon in metallic core melts and to put constraints on partitioning of carbon between silicate mantle and metallic core, we have determined the solubility of carbon in molten core metal at P- T conditions relevant for a shallow magma ocean.Experiments are performed at 2 GPa and to 2500 °C using a piston cylinder apparatus. Pure Fe-rod or a mixture of Fe-5.2%Ni loaded into graphite capsules were used as starting materials. Al coated run products are analyzed by EMP. Carbon concentration of 5.8 ± 0.4 wt.% at 2000 °C, 6.5 ± 0.9 wt.% at 2250 °C, and 7.5 ± 1.2 wt.% at 2500 °C are measured in quenched iron melt saturated with graphite. The trend of C solubility versus temperature for Fe-5.2 wt.% Ni melt, within analytical uncertainties, is similar to that of pure Fe.We have compared our solubility data and an estimate of the current carbon content of the mantle with the carbon content of core melts and residual mantle silicates respectively, derived from equilibrium batch or fractional segregation of core liquids, to constrain the partition coefficient of carbon between silicate and metallic melts in a magma ocean, DC. Translation of the limits of DC, derived from our solubility data, on calculation of carbon content of the residual silicate shows that the observed mantle concentration of carbon is too low to be matched by the process of shallow magma ocean fractionation of carbon between metal and silicate in a chondritic protoearth. If carbon solubility in liquid Fe does not change strongly as a function of pressure, this may indicate the presence of a hidden carbon- rich mantle reservoir untapped by oceanic volcanism. For the entire range of possible bulk Earth carbon content from chondritic to subchondritic and for the mantle carbon content of 50-1000 ppm, DC of 10-4- 100 are derived. But for 1000 ppm bulk Earth carbon, DC is 10-2-100. Using the complete range of possible DC for a magma ocean at ~2200 °C, we predict maximum carbon content of the Earth's core to be 6-7 wt.% and a preferred value of 0.25 ± 0.15 wt.% carbon for a bulk Earth carbon concentration of 1000 ppm. Based on our estimate, the core is likely one of the most enriched terrestrial reservoirs of carbon with concentration as high as 0.4 wt.%, which likely is at least an order of magnitude higher than that of the average mantle. The higher carbon content of OIBs compared to MORBs thus may derive in part from core contributions to mantle plumes.[1] Dasgupta, R. and Hirschmann, M.M. 2006, Nature 440, 659- 662. [2] Wood, B.J. 1993, Earth Planet Sci Lett 117, 593-607.

Dasgupta, R.; Walker, D.

2007-12-01

100

Equivalence Postulate and Quantum Origin of Gravitation  

Microsoft Academic Search

We suggest that quantum mechanics and gravity are intimately related. In particular, we investigate the quantum Hamilton-Jacobi equation in the case of two free particles and show that the quantum potential, which is attractive, may generate the gravitational potential. The investigation, related to the formulation of quantum mechanics based on the equivalence postulate, is based on the analysis of the

Marco Matone; G. Galilei

2000-01-01

101

Melt layer statistic of two firn cores recently drilled at Dye3 and South dome in the dry snow zone of Southern Greenland  

NASA Astrophysics Data System (ADS)

In the last couple of years remote sensing data have shown large areas of wet snow in the Southern part of the Greenland ice sheet. These melt features are attributed to the overall warming trend. Persistent warming implies changes in the firn layer as well. Even in areas of the dry snow zone one can observe sporadically a few ice lenses within the firn column indicating refrozen meltwater from warm events in the past. In our contribution we want to close the gap between investigations of firn cores drilled in the 70's and the observational record of remote sensing data over the last decade in South Greenland. The focus lies on firn of the dry snow zone which is sensitive against changes in a warming atmosphere and cold enough to prevent a longway percolation path of meltwater to several firn layers. To this end we had drilled two 45m-long firn cores at the former drilling sites of DYE3 (65°11'N, 43°49'W) and South Dome (SD) (63°32'N, 44°34'W) during a aircraft-supported field campaign 2012. The retrieved 3inch-firn core segments of 1m length are measured by a X-ray-scanning routine with the means of the core-scale AWI-ICE-CT. The 2d-density fields are calculated and allow to distinguish between refreezing meltwater and compacted firn. The depth-scales are converted to time-scales by using DEP (dielectric profiling) and (in case of DYE3) discrete sampled d18O measurements. Number density of melt layers and relative amount of melt show an synchronized behavior with an general increase over the last 30 years. Local maxima are observed in both sites at around 6-9m and 25m at DYE3 and 5-8m, 22m and 40m at SD.

Freitag, Johannes; Kipfstsuhl, Sepp; Hoerz, Sebastian; Eling, Lukas; Vinther, Bo; Popp, Trevor

2014-05-01

102

Modelling micro-level volume expansion during reactive melt infiltration using non-isothermal unreacted-shrinking core models  

Microsoft Academic Search

Reactive melt infiltration is a process used to manufacture silicon carbide fibre-reinforced silicon carbide (SiC\\/SiC) composites. The present stage of research on reactive infiltration is primarily experimental, wherein complete infiltration is rarely achieved and unreacted silicon still remains in the composite. This paper deals with the micro-modelling aspect of reactive melt infiltration and estimates volume expansion due to mass transfer

G. Rajesh; R. B. Bhagat

1998-01-01

103

A MELCOR Application to Two Light Water Reactor Nuclear Power Plant Core Melt Scenarios with Assumed Cavity Flooding Action  

Microsoft Academic Search

The MELCOR 1.8.4 code Bottom Head package has been applied to simulate two reactor cavity flooding scenarios for when the corium material relocates to the lower-plenum region in postulated severe accidents. The applications were preceded by a review of two main physical models, which highly impacted the results. A model comparison to available bibliography models was done, which allowed some

Francisco Martin-Fuertes; Juan Manuel Martin-Valdepenas; Jose Mira; Maria Jesus Sanchez

2003-01-01

104

A broad Galápagos hotspot melting anomaly and disturbance of the underlying core- mantle boundary: A natural laboratory for studying interaction between the core-mantle boundary and overlying lithosphere?  

NASA Astrophysics Data System (ADS)

New evidence from direct isotopic dating of the oceanic hotspot record is suggesting that hotspot melting anomalies might be much broader than commonly inferred from the dimensions of individual seamount chains and aseismic ridges and their associated active `volcanic` hotspots. Such an inference is supported by recent thermo-chemical numerical modelling exploring scenarios where upwelling structures are more irregular in shape and behaviour compared to a classic thermal plume `head-tail` (e.g., Farnetani and Samuel, 2006). New age data from the Galápagos Volcanic Province suggest that it developed via the progression of broad regions of widespread, long-lived and possibly concurrent volcanism resulting from tectonic plate motion over a broad Galápagos hotspot melting anomaly (O'Connor et al., 2007). Seismic imaging of the core-mantle boundary under the Cocos plate shows a 100-km vertical step occurring in an otherwise flat D" shear velocity discontinuity (Thomas et al., 2004, Hutko et al., 2006, Kito et al., 2007). One possible explanation is that folding and piling of a cold subducted slab on reaching the core-mantle boundary might account for this lateral variation in terms of a post-perovskite phase change (Thomas et al., 2004, Hutko et al., 2006, Kito et al., 2007). Low velocities inferred at the edge of this proposed slab material may result from the lateral displacement of a thin hot thermal boundary layer leading to upwelling at the tip of the slab, (Thomas et al., 2004, Hutko et al., 2006, Kito et al., 2007), which in turn might possible be connected to our inferred broad hotspot melting anomaly. The combination of the recent imaging of an anomaly at the D"-discontinuity and the inference of a broad overlying Galápagos hotspot melting anomaly suggest that the Galápagos region is an ideal natural-laboratory for studying the possibility of interaction between the core-mantle boundary and overlying lithosphere.

O'Connor, J. M.; Stoffers, P.; Wijbrans, J. R.; Worthington, T. J.

2007-12-01

105

Nonlinear damage analysis: Postulate and evaluation  

NASA Technical Reports Server (NTRS)

The objective of this program is to assess the viability of a damage postulate which asserts that the fatigue resistance curve of a metal is history dependent due to inelastic action. The study focusses on OFE copper because this simple model material accentuates the inelastic action central to the damage postulate. Data relevant to damage evolution and crack initiation are developed via a study of surface topography. The effects of surface layer residual stresses are explored via comparative testing as were the effects in initial prestraining. The results of the study very clearly show the deformation history dependence of the fatigue resistance of OFE copper. Furthermore the concept of deformation history dependence is shown to qualitatively explain the fatigue resistance of all histories considered. Likewise quantitative predictions for block cycle histories are found to accurately track the observed results. In this respect the assertion that damage per cycle for a given level of the damage parameter is deformation history dependent appears to be physically justified.

Leis, B. N.; Forte, T. P.

1983-01-01

106

Final results of the XR2-1 BWR metallic melt relocation experiment  

SciTech Connect

This report documents the final results of the XR2-1 boiling water reactor (BWR) metallic melt relocation experiment, conducted at Sandia National Laboratories for the U.S. Nuclear Regulatory Commission. The objective of this experiment was to investigate the material relocation processes and relocation pathways in a dry BWR core following a severe nuclear reactor accident such as an unrecovered station blackout accident. The imposed test conditions (initial thermal state and the melt generation rates) simulated the conditions for the postulated accident scenario and the prototypic design of the lower core test section (in composition and in geometry) ensured that thermal masses and physical flow barriers were modeled adequately. The experiment has shown that, under dry core conditions, the metallic core materials that melt and drain from the upper core regions can drain from the core region entirely without formation of robust coherent blockages in the lower core. Temporary blockages that suspended pools of molten metal later melted, allowing the metals to continue draining downward. The test facility and instrumentation are described in detail. The test progression and results are presented and compared to MERIS code analyses. 6 refs., 55 figs., 4 tabs.

Gauntt, R.O.; Humphries, L.L.

1997-08-01

107

Petrology of impactites from El'gygytgyn crater: Breccias in ICDP-drill core 1C, glassy impact melt rocks and spherules  

NASA Astrophysics Data System (ADS)

AbstractEl'gygytgyn is a 18 km diameter, 3.6 Ma old impact crater in NE Siberia. International Continental Scientific Drilling Program—El'gygytgyn hole 1C was drilled on the frozen crater lake, 2.3 km from the crater center to a final depth of 517 m below the lake floor. Petrographic and geochemical analyses of 26 drill <span class="hlt">core</span> samples, three impact <span class="hlt">melt</span> rocks from the surface, and seven glass spherules from surface deposits outside the crater are used to characterize the impactite inventory at El'gygytgyn. The bottom 98 m of hole 1C intersected monomict brecciated, unshocked, rhyolitic ignimbrite with minor intercalations of polymict breccia and mafic inclusions. These lithologies are overlain by 89 m of polymict breccia whose components occasionally exhibit scarce, low-degree shock metamorphic features. This unit is succeeded by 10 m of suevite that contains about 1 vol% glassy impact <span class="hlt">melt</span> shards <1 cm in size and a low amount of shock metamorphosed lithic clasts. The suevite is capped by a reworked fallout deposit that constitutes a transition over 4 m into lacustrine sedimentation. A higher abundance of shock metamorphosed lithic clasts, and glass spherules, some with Ni-rich spinel and admixture of an ultramafic component, characterize this unit. We tentatively interpret this impactite section as allochthonous breccia in the vicinity of El'gygytgyn's central ring uplift. The geochemical compositions of seven glass spherules from terrace deposits 2 km outside the crater and eight spherules from the reworked fallout deposit in hole 1C show far greater variability than the composition of impact <span class="hlt">melt</span> shards and impact <span class="hlt">melt</span> rocks. Some of these spherules also show strong enrichments in siderophile elements.</p> <div class="credits"> <p class="dwt_author">Wittmann, Axel; Goderis, Steven; Claeys, Philippe; Vanhaecke, Frank; Deutsch, Alexander; Adolph, Leonie</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">108</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5581684"> <span id="translatedtitle">Status of the MELTSPREAD-1 computer code for the analysis of transient spreading of <span class="hlt">core</span> debris <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A transient, one dimensional, finite difference computer code (MELTSPREAD-1) has been developed to predict spreading behavior of high temperature <span class="hlt">melts</span> flowing over concrete and/or steel surfaces submerged in water, or without the effects of water if the surface is initially dry. This paper provides a summary overview of models and correlations currently implemented in the code, code validation activities completed thus far, LWR spreading-related safety issues for which the code has been applied, and the status of documentation for the code.</p> <div class="credits"> <p class="dwt_author">Farmer, M.T.; Sienicki, J.J.; Spencer, B.W.; Chu, C.C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">109</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10136699"> <span id="translatedtitle">Status of the MELTSPREAD-1 computer code for the analysis of transient spreading of <span class="hlt">core</span> debris <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A transient, one dimensional, finite difference computer code (MELTSPREAD-1) has been developed to predict spreading behavior of high temperature <span class="hlt">melts</span> flowing over concrete and/or steel surfaces submerged in water, or without the effects of water if the surface is initially dry. This paper provides a summary overview of models and correlations currently implemented in the code, code validation activities completed thus far, LWR spreading-related safety issues for which the code has been applied, and the status of documentation for the code.</p> <div class="credits"> <p class="dwt_author">Farmer, M.T.; Sienicki, J.J.; Spencer, B.W.; Chu, C.C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">110</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1693394"> <span id="translatedtitle">The aetiology of SARS: Koch's <span class="hlt">postulates</span> fulfilled.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Proof that a newly identified coronavirus, severe acute respiratory syndrome coronavirus (SARS-CoV) is the primary cause of severe acute respiratory syndrome (SARS) came from a series of studies on experimentally infected cynomolgus macaques (Macaca fascicularis). SARS-CoV-infected macaques developed a disease comparable to SARS in humans; the virus was re-isolated from these animals and they developed SARS-CoV-specific antibodies. This completed the fulfilment of Koch's <span class="hlt">postulates</span>, as modified by Rivers for viral diseases, for SARS-CoV as the aetiological agent of SARS. Besides the macaque model, a ferret and a cat model for SARS-CoV were also developed. These animal models allow comparative pathogenesis studies for SARS-CoV infections and testing of different intervention strategies. The first of these studies has shown that pegylated interferon-alpha, a drug approved for human use, limits SARS-CoV replication and lung damage in experimentally infected macaques. Finally, we argue that, given the worldwide nature of the socio-economic changes that have predisposed for the emergence of SARS and avian influenza in Southeast Asia, such changes herald the beginning of a global trend for which we are ill prepared.</p> <div class="credits"> <p class="dwt_author">Osterhaus, A D M E; Fouchier, R A M; Kuiken, T</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">111</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/20837795"> <span id="translatedtitle">A MELCOR Application to Two Light Water Reactor Nuclear Power Plant <span class="hlt">Core</span> <span class="hlt">Melt</span> Scenarios with Assumed Cavity Flooding Action</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The MELCOR 1.8.4 code Bottom Head package has been applied to simulate two reactor cavity flooding scenarios for when the corium material relocates to the lower-plenum region in <span class="hlt">postulated</span> severe accidents. The applications were preceded by a review of two main physical models, which highly impacted the results. A model comparison to available bibliography models was done, which allowed some code modifications on selected default assumptions to be undertaken. First, the corium convective heat transfer to the wall when it becomes liquid was modified, and second, the default nucleate boiling regime curve in a submerged hemisphere was replaced by a new curve (and, to a much lesser extent, the critical heat flux curve was slightly varied).The applications were devoted to two prototypical light water reactor nuclear power plants, a 2700-MW(thermal) pressurized water reactor (PWR) and a 1381-MW(thermal) boiling water reactor (BWR). The main conclusions of the cavity flooding simulations were that the PWR lower-head survivability is extended although it is clearly not guaranteed, while in the BWR sequence the corium seems to be successfully arrested in the lower plenum.Three applications of the CFX 4.4 computational fluid dynamics code were carried out in the context of the BWR scenario to support the first modification of the aforementioned two scenarios for MELCOR.Finally, in the same BWR context, a statistic predictor of selected output parameters as a function of input parameters is presented, which provides reasonable results when compared to MELCOR full calculations in much shorter CPU processing times.</p> <div class="credits"> <p class="dwt_author">Martin-Fuertes, Francisco; Martin-Valdepenas, Juan Manuel; Mira, Jose; Sanchez, Maria Jesus [Universidad Politecnica de Madrid (Spain)</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-10-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">112</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1130/2009.2458(10)"> <span id="translatedtitle">Megablocks and <span class="hlt">melt</span> pockets in the Chesapeake Bay impact structure constrained by magnetic field measurements and properties of the Eyreville and Cape Charles <span class="hlt">cores</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">We use magnetic susceptibility and remanent magnetization measurements of the Eyreville and Cape Charles <span class="hlt">cores</span> in combination with new and previously collected magnetic field data in order to constrain structural features within the inner basin of the Chesapeake Bay impact structure. The Eyreville <span class="hlt">core</span> shows the first evidence of several-hundred-meter-thick basement-derived megablocks that have been transported possibly kilometers from their pre-impact location. The magnetic anomaly map of the structure exhibits numerous short-wavelength (<2 km) variations that indicate the presence of magnetic sources within the crater fill. With <span class="hlt">core</span> magnetic properties and seismic reflection and refraction results as constraints, forward models of the magnetic field show that these sources may represent basementderived megablocks that are a few hundred meters thick or <span class="hlt">melt</span> bodies that are a few dozen meters thick. Larger-scale magnetic field properties suggest that these bodies overlie deeper, pre-impact basement contacts between materials with different magnetic properties such as gneiss and schist or gneiss and granite. The distribution of the short-wavelength magnetic anomalies in combination with observations of small-scale (1-2 mGal) gravity field variations suggest that basement-derived megablocks are preferentially distributed on the eastern side of the inner crater, not far from the Eyreville <span class="hlt">core</span>, at depths of around 1-2 km. A scenario where additional basement-derived blocks between 2 and 3 km depth are distributed throughout the inner basin-and are composed of more magnetic materials, such as granite and schist, toward the east over a large-scale magnetic anomaly high and less magnetic materials, such as gneiss, toward the west where the magnetic anomaly is lower-provides a good model fi t to the observed magnetic anomalies in a manner that is consistent with both gravity and seismic-refraction data. ?? 2009 The Geological Society of America.</p> <div class="credits"> <p class="dwt_author">Shah, A. K.; Daniels, D. L.; Kontny, A.; Brozena, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">113</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFM.P14A..08T"> <span id="translatedtitle">Boundary pressure of inter-connection of Fe-Ni-S <span class="hlt">melt</span> in olivine based on in-situ X-ray tomography: Implication to <span class="hlt">core</span> formation in asteroids</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Interconnectivity of Fe-alloy <span class="hlt">melt</span> in crystalline silicates is important property for the <span class="hlt">core</span> formation mechanism in planetary interior. In previous studies, the interconnectivity of Fe-alloy <span class="hlt">melt</span> has been studied based on textural observation of recovered samples from high pressure and temperature. However, there is no observation under high pressure and temperature. We have developed 80-ton uni-axial press for X-ray computed micro-tomography (X-CT) and performed X-CT measurement under high pressure (Urakawa et al. 2010). Here we report X-CT measurement of Fe-Ni-S <span class="hlt">melt</span> in crystalline olivine and interconnectivity of the <span class="hlt">melt</span> up to 3.5 GPa and 1273 K. X-CT measurements were carried out at BL20B2 beamline, SPring-8 synchrotron facility. The sample was powder mixture of Fe-Ni-S and olivine, which was enclosed in graphite capsule. Heating was performed using a cylindrical graphite furnace. Pressure was generated using opposed toroidal-shape WC anvil. The uni-axial press was set on the rotational stage and X-ray radiography image of the sample was collected using CCD camera from 0°to 180°with 0.3° step. 3-D image of the sample was obtained by reconstructing the 2-D radiography image. The 3-D CT image shows that the size of the Fe-Ni-S <span class="hlt">melt</span> increased significantly compared to that before <span class="hlt">melting</span> below 2.5 GPa, suggesting that the <span class="hlt">melt</span> was interconnected in olivine crystals. On the other hand, 3-D texture of the sample at 3.5 GPa did not show difference from that before <span class="hlt">melting</span>. Therefore, the boundary of inter-connection of Fe-Ni-S <span class="hlt">melt</span> is likely to locate between 2.5 and 3.5 GPa. This result is important application for the <span class="hlt">core</span> formation mechanism especially in small bodies, such as differentiated asteroids.</p> <div class="credits"> <p class="dwt_author">Terasaki, H.; Urakawa, S.; Uesugi, K.; Nakatsuka, A.; Funakoshi, K.; Ohtani, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">114</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=perceptron&id=ED141089"> <span id="translatedtitle">A Conceptual Derivation of Einstein's <span class="hlt">Postulates</span> of Special Relativity.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">This document presents a discussion and conceptual derivation of Einstein's <span class="hlt">postulates</span> of special relativity. The perceptron approach appears to be a fundamentally new manner of regarding physical phenomena and it is hoped that physicists will interest themselves in the concept. (Author)</p> <div class="credits"> <p class="dwt_author">Bearden, Thomas E.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">115</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=yogurt&pg=2&id=EJ415520"> <span id="translatedtitle">Safely Teaching Koch's <span class="hlt">Postulates</span> on the Causation of Infectious Disease.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Described is an activity in which the interactions between a parasite and its host may be demonstrated using the relationship between yogurt and two species of bacteria. Background information on Koch's <span class="hlt">postulates</span> is provided. Materials, laboratory procedures, and results are discussed. (CW)</p> <div class="credits"> <p class="dwt_author">Stewart, Peter R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">116</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.agu.org/journals/jd/jd0824/2008JD011083/2008JD011083.pdf"> <span id="translatedtitle">Stratigraphic analysis of an ice <span class="hlt">core</span> from the Prince of Wales Icefield, Ellesmere Island, Arctic Canada, using digital image analysis: High-resolution density, past summer warmth reconstruction, and <span class="hlt">melt</span> effect on ice <span class="hlt">core</span> solid conductivity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">High-resolution (1 mm) stratigraphic information was derived from digital image analysis of an ice <span class="hlt">core</span> from the Prince of Wales (POW) Icefield, Central Ellesmere Island, Canada. Following careful image processing, a profile of ice <span class="hlt">core</span> transmitted light was derived from the greyscale images and used to reconstruct high-resolution density variations for the unfractured sections of the <span class="hlt">core</span>. Images were further</p> <div class="credits"> <p class="dwt_author">Christophe Kinnard; Roy M. Koerner; Christian M. Zdanowicz; David A. Fisher; Jiancheng Zheng; Martin J. Sharp; Lindsey Nicholson; Bernard Lauriol</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">117</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3120994"> <span id="translatedtitle">The Four <span class="hlt">Postulates</span> of Freudian Unconscious Neurocognitive Convergences</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">In the 1980s, the terms “cognitive unconscious” were invented to denominate a perspective on unconscious mental processes independent from the psychoanalytical views. For several reasons, the two approaches to unconscious are generally conceived as irreducible. Nowadays, we are witnessing a certain convergence between both fields. The aim of this paper consists in examining the four basic <span class="hlt">postulates</span> of Freudian unconscious at the light of neurocognitive sciences. They posit: (1) that some psychological processes are unconsciously performed and causally determine conscious processes, (2) that they are governed by their own cognitive rules, (3) that they set out their own intentions, (4) and that they lead to a conflicting organization of psyche. We show that each of these <span class="hlt">postulates</span> is the subject of empirical and theoretical works. If the two fields refer to more or less similar mechanisms, we propose that their opposition rests on an epistemological misunderstanding. As a conclusion, we promote a conservative reunification of the two perspectives.</p> <div class="credits"> <p class="dwt_author">Arminjon, Mathieu</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">118</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1982M%26P....26...93L"> <span id="translatedtitle">A <span class="hlt">postulate</span> leading to the Titius-Bode law</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A formalism similar to Sommerfeld's (1916) is examined, which accounts for the planetary distribution of the solar system. The analysis is based on the early quantum theory, and emphasizes that no connection exists between the Sommerfeld quantum rule and the assumed equation in the present analysis. The assumed equation seems to reflect a nonclassical property of gravitation, and may be a pure coincidence leading to the T-B law, and thus may have no significance other than that of an exotic <span class="hlt">postulate</span>.</p> <div class="credits"> <p class="dwt_author">Louise, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">119</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/12547052"> <span id="translatedtitle">Equivalence <span class="hlt">Postulate</span> and the Quantum Potential of Two Free Particles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Commutativity of the diagram of the maps connecting three one--particle\\u000astate, implied by the Equivalence <span class="hlt">Postulate</span> (EP), gives a cocycle condition\\u000awhich unequivocally leads to the quantum Hamilton--Jacobi equation. Energy\\u000aquantization is a direct consequences of the local homeomorphicity of the\\u000atrivializing map. We review the EP and show that the quantum potential for two\\u000afree particles, which depends on</p> <div class="credits"> <p class="dwt_author">Marco Matone; G. Galilei</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">120</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19740003537&hterms=Eyring&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DEyring"> <span id="translatedtitle"><span class="hlt">Melting</span> of iron by significant structure theory</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">From Eyring's method of significant structures, a partition function is derived for liquid iron. The solid at high temperature is described in the Einstein approximation. Magnetic and electronic contributions to the thermodynamic properties of both the liquid and solid phases are considered. The model is compatible with properties (thermal expansion, compressibility, heat capacity, entropy of <span class="hlt">melting</span>, and volume change on <span class="hlt">melting</span>) at one atm. The <span class="hlt">melting</span> temperature at high pressure is found by satisfying the requirement that the Gibbs free energies of the liquid and solid phases are equal at the <span class="hlt">melting</span> temperature. Under conditions at the earth's <span class="hlt">core</span>-mantle boundary, the <span class="hlt">melting</span> temperature of iron is greater than approximately 5000 K, and under inner-outer <span class="hlt">core</span> conditions the <span class="hlt">melting</span> temperature is greater than approximately 7000 K. These estimates are consistent with the Lindemann <span class="hlt">melting</span> law, but not with the Kraut-Kennedy <span class="hlt">melting</span> law.</p> <div class="credits"> <p class="dwt_author">Leppaluoto, D. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1972-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_5");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">121</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://concord.org/stem-resources/melting-ice"> <span id="translatedtitle"><span class="hlt">Melting</span> Ice</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Monitor the temperature of a <span class="hlt">melting</span> ice cube and use temperature probes to electronically plot the data on graphs. Investigate what temperature the ice is as it <span class="hlt">melts</span> in addition to monitoring the temperature of liquid the ice is submerged in.</p> <div class="credits"> <p class="dwt_author">Consortium, The C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-13</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">122</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://onramp.nsdl.org/eserv/onramp:17106/Melting_Icebergs.pdf"> <span id="translatedtitle"><span class="hlt">Melting</span> Icebergs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This formative assessment item uncovers student ideas and misconceptions about <span class="hlt">melting</span> icebergs. It determines if students believe that water levels will rise due to <span class="hlt">melting</span> icebergs. Resources provided will assist teachers. It gives instructional support as well as information for teachers. This probe is aligned to National Science Education Standards (NSES).</p> <div class="credits"> <p class="dwt_author">Fries-Gaither, Jessica</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">123</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/mq1861v48485h3l3.pdf"> <span id="translatedtitle"><span class="hlt">Melting</span> relationships in the system Fe-Feo at high pressures: Implications for the composition and formation of the earth's <span class="hlt">core</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A reconnaissance investigation has been carried out on <span class="hlt">melting</span> relationships in the system Fe-FeO at pressures up to 25 GPa\\u000a and temperatures up to 2200 C using an MA-8 apparatus. Limited studies were also made of the Co-CoO and Ni-NiO systems. In\\u000a the system FeFeO, the rapid exsolution of FeO from liquids during quenching causes some difficulties in interpretation of</p> <div class="credits"> <p class="dwt_author">Takumi Kato; A. E. Ringwood</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">124</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19730037391&hterms=gruneisen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2522gruneisen%2522"> <span id="translatedtitle">The <span class="hlt">core</span> paradox.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Rebuttal of suggestions from various critics attempting to provide an escape from the seeming paradox originated by Higgins and Kennedy's (1971) proposed possibility that the liquid in the outer <span class="hlt">core</span> was thermally stably stratified and that this stratification might prove a powerful inhibitor to circulation of the outer <span class="hlt">core</span> fluid of the kind <span class="hlt">postulated</span> for the generation of the earth's magnetic field. These suggestions are examined and shown to provide no reasonable escape from the <span class="hlt">core</span> paradox.</p> <div class="credits"> <p class="dwt_author">Kennedy, G. C.; Higgins, G. H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">125</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/47724230"> <span id="translatedtitle">The <span class="hlt">Melting</span> Process of Acetylsalicylic Acid Single Crystals</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Crystallisation is generally regarded as a nucleation — growth mechanism of a solid phase and often studied using thermo chemical\\u000a methods. The present work <span class="hlt">postulates</span> an analogy to <span class="hlt">melting</span> processes, looking at <span class="hlt">melting</span> as nucleation — growth of a liquid\\u000a phase. The <span class="hlt">melting</span> process of acetylsalicylic acid single crystals was investigated by DSC measurements under isothermal conditions.\\u000a The fraction of</p> <div class="credits"> <p class="dwt_author">G. L. Perlovich; A. Bauer-Brandl</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">126</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5244524"> <span id="translatedtitle">Prism reactor system design and analysis of <span class="hlt">postulated</span> unscrammed events</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Key safety characteristics of the PRISM reactor system include the passive reactor shutdown characteristic and the passive shutdown heat removal system, RVACS. While these characteristics are simple in principle, the physical processes are fairly complex, particularly for the passive reactor shutdown. It has been possible to adapt independent safety analysis codes originally developed for the Clinch River Breeder Reactor review, although some limitations remain. In this paper, the analyses of <span class="hlt">postulated</span> unscrammed events are discussed, along with limitations in the predictive capabilities and plans to correct the limitations in the near future. 6 refs., 4 figs.</p> <div class="credits"> <p class="dwt_author">Van Tuyle, G.J.; Slovik, G.C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">127</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5417203"> <span id="translatedtitle">PRISM reactor system design and analysis of <span class="hlt">postulated</span> unscrammed events</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Key safety characteristics of the PRISM reactor system include the passive reactor shutdown characteristics and the passive shutdown heat removal system, RVACS. While these characteristics are simple in principle, the physical processes are fairly complex, particularly for the passive reactor shutdown. It has been possible to adapt independent safety analysis codes originally developed for the Clinch River Breeder Reactor review, although some limitations remain. In this paper, the analyses of <span class="hlt">postulated</span> unscrammed events are discussed, along with limitations in the predictive capabilities and plans to correct the limitations in the near future. 6 refs., 4 figs.</p> <div class="credits"> <p class="dwt_author">Van Tuyle, G.J.; Slovik, G.C. (Brookhaven National Lab., Upton, NY (United States)); Rosztoczy, Z.; Lane, J. (Nuclear Regulatory Commission, Washington, DC (United States))</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">128</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://video.nationalgeographic.com/video/player/environment/global-warming-environment/glacier-melt.html"> <span id="translatedtitle">Glacier <span class="hlt">Melt</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This short video shows an example of <span class="hlt">melting</span> alpine glaciers in the Austrian Alps (Goldberg Glacier). Disappearing alpine glaciers have social and environmental impacts, including the decline of fresh water supplies and contributing to sea level rise.</p> <div class="credits"> <p class="dwt_author">Geographic, National</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">129</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pbslearningmedia.org/resource/ean08.sci.ess.earthsys.permafrost/"> <span id="translatedtitle"><span class="hlt">Melting</span> Permafrost</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this video adapted from the International Institute for Sustainable Development, see <span class="hlt">melting</span> permafrost and hear Alaska Native peoples and Western scientists discuss its impact on Inuit culture and resources.</p> <div class="credits"> <p class="dwt_author">Foundation, Wgbh E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-26</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">130</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://thedianerehmshow.org/shows/2006-01-06"> <span id="translatedtitle">Arctic <span class="hlt">Melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this radio broadcast, a panel of experts joins National Public Radio journalist Diane Rehm to discuss rising temperatures at the North Pole and what the <span class="hlt">melting</span> may mean for the climate, national boundaries, and oil exploration. There is discussion of the 1982 U.N. convention, Law of the Sea, which is guiding new mapping due to arctic <span class="hlt">melting</span> and changing coastlines; and why the decreasing need for Arctic ice-breakers is making oil exploration mapping easier. There is explanation of why the Antarctic may <span class="hlt">melt</span> a couple of decades after the Arctic; why we know sea levels will rise as polar ice <span class="hlt">melts</span>; and why we know humans are causing the <span class="hlt">melting</span>, as opposed to astronomical configurations or other natural causes leading to <span class="hlt">melting</span> cycles. The broadcast is 51 minutes in length, but the discussion about the Arctic starts 32 minutes into the program and lasts 19 minutes. You may listen to the archived broadcast in Windows Media or Real Audio format.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-06-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">131</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMMR13A..06M"> <span id="translatedtitle"><span class="hlt">Melting</span> curve of iron to 200 GPa</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Earth's <span class="hlt">core</span> is composed of iron and few percent of lighter elements. Therefore, the knowledge of the <span class="hlt">melting</span> temperatures of iron at the inner-<span class="hlt">core</span> outer-<span class="hlt">core</span> boundary is of fundamental importance to better constrain the temperature distribution in the Earth's <span class="hlt">core</span>. This temperature distribution is in turn essential to model Earth's heat budget and geodynamo. Here, we report a new <span class="hlt">melting</span> curve of iron from in situ X-ray diffraction in the double-sided laser heating diamond anvil cell system installed at beamline ID27 of the ESRF. We show that the fast re-crystallization process observed at high temperature is not a good criterion for assessing <span class="hlt">melting</span> temperatures. In the present work, we used the appearance of a clear X-ray diffuse scattering as an unambiguous signature of <span class="hlt">melting</span>. The obtained <span class="hlt">melting</span> curve is in good agreement with recent ab initio calculation and with shock compression experiments.</p> <div class="credits"> <p class="dwt_author">Mezouar, M.; Anzellini, S.; Dewaele, A.; Morard, G.; Loubeyre, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">132</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10117067"> <span id="translatedtitle">Analyses of <span class="hlt">postulated</span> ALMR containment and steam generator building accidents using the CONTAIN-LMR code</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The development of liquid metal reactor concepts with passive safety characteristics is in progress at the General Electric Company under contract to the US Department of Energy. To assess the performance of these systems under <span class="hlt">postulated</span> severe accident conditions analyses of containment accidents relating to the breach of the primary coolant boundary of the Department of Energy Advanced Liquid Metal Reactor were completed by Westinghouse Hanford Company for the plant designer General Electric. A series of three accident cases were selected by General Electric for characterizing the containment responding to a hypothetical <span class="hlt">core</span> disruptive accident. In addition, the Advanced Liquid Metal Reactor Steam Generator Building was also analyzed to demonstrate the acceptability of the Steam Generator Building sodium fire protection strategy related to a design-basis leak.</p> <div class="credits"> <p class="dwt_author">Chiao, T.; Wood, S.A.; Shen, P.K.; Baker, R.B. [Westinghouse Hanford Co., Richland, WA (United States); Gluekler, E.L. [General Electric Co., Richland, WA (United States). Hanford Atomic Products Operation</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">133</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70015742"> <span id="translatedtitle">A random spatial network model based on elementary <span class="hlt">postulates</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">In contrast to the random topology model, this model ascribes a unique spatial specification to generated drainage networks, a distinguishing property of some network growth models. The simplicity of the <span class="hlt">postulates</span> creates an opportunity for potential analytic investigations of the probabilistic structure of the drainage networks, while the spatial specification enables analyses of spatially dependent network properties. In the random topology model all drainage networks, conditioned on magnitude (number of first-order streams), are equally likely, whereas in this model all spanning trees of a grid, conditioned on area and drainage density, are equally likely. As a result, link lengths in the generated networks are not independent, as usually assumed in the random topology model. -from Authors</p> <div class="credits"> <p class="dwt_author">Karlinger, M. R.; Troutman, B. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">134</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/fdsys/pkg/FR-2011-07-20/pdf/2011-18270.pdf"> <span id="translatedtitle">76 FR 43356 - Evaluations of Explosions <span class="hlt">Postulated</span> To Occur at Nearby Facilities and on Transportation Routes...</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013</a></p> <p class="result-summary">...<span class="hlt">Postulated</span> To Occur at Nearby Facilities and on Transportation Routes Near Nuclear Power Plants AGENCY: Nuclear Regulatory Commission...<span class="hlt">Postulated</span> to Occur at Nearby Facilities and on Transportation Routes Near Nuclear Power Plants''. This draft regulatory guide...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-07-20</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">135</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10115578"> <span id="translatedtitle">Analysis of <span class="hlt">postulated</span> events for the revised ALMR/PRISM design</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The Nuclear Regulatory Commission (NRC) is continuing a pre-application review of the 471 MWt, Liquid Metal Reactor, PRISM by General Electric, with Brookhaven National Laboratory providing technical support. The revised design has been evaluated, using the SSC code, for an unscrammed loss of heat sink (ULOHS), an unscrammed loss of flow (ULOF) with and without the Gas Expansion Modules (GEMs), and a 40{cents} unscrammed transient overpower (UTOP) event. The feedback effects for U-27Pu-10Zr metal fuel were modeled in SSC. The ULOHS accident was determined to be a benign event for the design, with the reactor power transitioning down to a decay heat level within 500s. The power during the <span class="hlt">postulated</span> ULOF events, with the GEMs functioning, transitioned to decay heat levels without fuel damage, and included a 300K margin to sodium saturation. The case without the GEMs had only a 160K margin to sodium saturation and higher fuel temperatures. In addition, the clad was predicted to quickly pass through the eutectic phase (between fuel and clad), and some clad wastage would result. The 40{cents} UTOP was predicted to raise the power to 1.8 rated, which later stabilized near 1.2 times full power. SSC predicted some localized fuel <span class="hlt">melting</span> for the event, but the significance of this localized damage has not yet been determined. If necessary, the vendor has options to reduce the maximum reactivity insertion below 40{cents}.</p> <div class="credits"> <p class="dwt_author">Slovik, G.C.; Van Tuyle, G.J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-12-31</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">136</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6122462"> <span id="translatedtitle">Analysis of <span class="hlt">postulated</span> events for the revised ALMR/PRISM design</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The Nuclear Regulatory Commission (NRC) is continuing a pre-application review of the 471 MWt, Liquid Metal Reactor, PRISM by General Electric, with Brookhaven National Laboratory providing technical support. The revised design has been evaluated, using the SSC code, for an unscrammed loss of heat sink (ULOHS), an unscrammed loss of flow (ULOF) with and without the Gas Expansion Modules (GEMs), and a 40{cents} unscrammed transient overpower (UTOP) event. The feedback effects for U-27Pu-10Zr metal fuel were modeled in SSC. The ULOHS accident was determined to be a benign event for the design, with the reactor power transitioning down to a decay heat level within 500s. The power during the <span class="hlt">postulated</span> ULOF events, with the GEMs functioning, transitioned to decay heat levels without fuel damage, and included a 300K margin to sodium saturation. The case without the GEMs had only a 160K margin to sodium saturation and higher fuel temperatures. In addition, the clad was predicted to quickly pass through the eutectic phase (between fuel and clad), and some clad wastage would result. The 40{cents} UTOP was predicted to raise the power to 1.8 rated, which later stabilized near 1.2 times full power. SSC predicted some localized fuel <span class="hlt">melting</span> for the event, but the significance of this localized damage has not yet been determined. If necessary, the vendor has options to reduce the maximum reactivity insertion below 40{cents}.</p> <div class="credits"> <p class="dwt_author">Slovik, G.C.; Van Tuyle, G.J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">137</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5431773"> <span id="translatedtitle">Vapor transport of fission products in <span class="hlt">postulated</span> severe light water reactor accidents</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A methodology based on chemical thermodynamics has been developed to treat the transport of volatile fission products (FPs) through the <span class="hlt">core</span> and the primary system. The FPs considered are cesium, iodine, tellurium, strontium, and ruthenium, which may pose the major biohazard in <span class="hlt">postulated</span> severe accidents in light water reactors. The vapor transport of FPs depends on the volatilities of the chemical compounds that are formed in the carrier gas environment in which the FPs are released and transported. Chemically stable forms were evaluated by minimizing the total free energies of the FP/ fuel/gas environment systems. Many gaseous species for each FP were considered and their partial pressures calculated over a range of temperatures (600 to 3000K), the carrier gas environments (total pressure and ratio of H/sub 2//H/sub 2/O), and the total amount of FPs in the system. It was found that the major dependence of the concentration of the FPs was on the gas temperature, and a model was developed to predict the source of volatile FPs. The model showed that the FPs leaving the <span class="hlt">core</span> region would condense in the cooler regions of the upper plenum and/or the primary system either on the cold surfaces or be transported further as aerosols.</p> <div class="credits"> <p class="dwt_author">Cubicciotti, D.; Sehgal, B.R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">138</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=https://scout.wisc.edu/Reports/NSDL/PhysSci/2003/ps-031031#TopicInDepth"> <span id="translatedtitle"><span class="hlt">Melting</span> Glaciers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Due to the potential disastrous consequences to the environment and to numerous societies, scientists, governments, and civilians are concerned with the growing trend of glacial <span class="hlt">melt</span>. This topic-in-depth explores various geographic regions where this phenomenon has recently been observed. Providing background into the study of glaciology, this report begins with a Web site (1) discussing the unique features of glaciers. The US Army Corps of Engineers offers visitors an insight to glacial properties including their locations, movements, and influences; along with a series educational images. The second site (2) explains the exceptionality of the two hundred sixty six glaciers at Glacier National Park. Through a collection of images, animations, and pictures provided by the National Park Service, users can learn about ice dams, climatic impacts, and the erosive powers of ice and water. The rest of the topic-in-depth discusses findings of glacial <span class="hlt">melting</span> from around the world. NASA (3) addresses the Artic warming's affects on glacier formations. This Web site provides a few animations displaying ice sheet extent and the cracking of icebergs. On a positive note, visitors can learn how the decrease in glaciers has opened up new habitat for some Artic species. The next Web site (4), also by NASA, discusses the findings of a twenty-five year study of Patagonia's glaciers. Educators and students can discover how NASA utilized the Space Shuttle Endeavor to study the entire 17,200 square kilometer region. The site also discusses potential causes of the <span class="hlt">melting</span> in this region, which has contributed to almost ten percent of the global sea-level change from mountain glaciers. As reported by the BBC (5), Dr. Harrison at the University of Oxford has determined that the glaciers in parts of Kazakhstan have been decreasing annually by almost two cubic kilometers between 1955 and 2000. Visitors can learn how the <span class="hlt">melting</span> of these four hundred sixteen glaciers will adversely affect the region's rivers and its water supply. The Taipei Times (6) reports that the Swiss Alpine glacial <span class="hlt">melting</span> has probably intensified due to this summer's record-breaking heat wave. This Web site provides short, intriguing descriptions of consequences of the "rush of <span class="hlt">melt</span> water streaming from the ice wall." Users can learn about predictions in the 1990s that the glaciers would shrink to ten percent of their 1850 size by the end of the twenty first century. In the next Web site (7), the BBC provides a captivating illustration of the effects the Peruvian glacial <span class="hlt">melts</span> may have on tourism, the country's water supply, and more. Students and educators can learn about NASA studies showing cracks in the ice, which could lead to the flooding of large cities. Visitors can also find out how the recent glacier recessions have affected some ancient spiritual traditions. The last site, by the USGS, (8) features excerpts from Myrna Hall and Daniel Fagre's 2003 research paper in BioScience. Visitors can discover the <span class="hlt">melt</span> rate and spatial distributions of glaciers for two possible future climate situations. Providing an amazing animation, users will be amazed by the changes predicted by the model.</p> <div class="credits"> <p class="dwt_author">Enright, Rachel</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">139</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22039564"> <span id="translatedtitle">Reconstruction of intra-bundle fission density profile during a <span class="hlt">postulated</span> LOCA in a CANDU reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">In this paper, results related to the reconstruction of intra-bundle fission density profile for a 37-pin CANDU-6 bundle with the highest enthalpy deposition during a <span class="hlt">postulated</span> large LOCA stagnation break in a Bruce B <span class="hlt">core</span> are presented. Bruce B is a nuclear power plant in Kincardine, Ontario (Canada)), on the shores of Lake Huron with 4 CANDU reactors that are rated at about 750 MWe. The reconstruction of the fuel pin fission densities is based on steady-state, three-dimensional simulations with the Monte Carlo code MCNP for a subset of 27 out of 69 time steps during the first two seconds of the power pulse predicted for the fuel bundle at <span class="hlt">core</span> location V13/8. Two-group cross section data libraries are generated for MCNP at each time step by the lattice depletion neutron transport code HELIOS-1.7. To include the effect of the surrounding <span class="hlt">core</span> environment, the calculations are performed with time-dependent albedo boundary conditions inferred from a full <span class="hlt">core</span> simulation of the transient by the nodal diffusion code NESTLE with HELIOS homogenized cross-sections. It is found that the local peaking factor (LPF) in the outer ring varies during the transient, but never exceeds its value before the transient. Inclusion of the <span class="hlt">core</span> environment increases the LPF in the outer ring. For the analyzed case, the increase is 0.72% with a relative error of 0.01% for the LPF before the transient and 0.55% (with a relative error of 0.01%) for the maximum average LPF during the transient. The latter is based on only four selected transient time points. Note that the immediate environment of the 'hot bundle' does not contain any reactivity devices or other perturbing factors. As a result, the increases observed in the LPF in the outer ring may not be representative of the situations in which 'other' <span class="hlt">core</span> environment perturbing factors are present. To determine the effect of these factors on the LPF, further analyses of a bundle in the proximity of control devices should be carried out. (authors)</p> <div class="credits"> <p class="dwt_author">Ilas, D. [Oak Ridge National Laboratory (United States); Rahnema, F. [Georgia Inst. of Technology (United States); Nuclear and Radiological Engineering/Medical Physics Programs, George W. Woodruff School, Georgia Inst. of Technology, Atlanta, GA 30332-0405 (United States); Serghiuta, D. [Canadian Nuclear Safety Commission (Canada); Sarsour, H.; Turinsky, P. J. [North Carolina State Univ. (United States); Stamm'ler, R. [Studsvik Scandpower AS (Norway)</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">140</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6477833"> <span id="translatedtitle">Dynamics of surface <span class="hlt">melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The objectives of this program is to study the phenomenon of surface <span class="hlt">melting</span> of single crystals of metals, to test for its existence, and to investigate its dynamics. Both conventional static electron diffraction and dynamic ultrafast electron diffraction are used in our study. This year, the ultrahigh vacuum facility containing the picosecond electron reflection high-energy electron diffraction system was equipped with a cylindrical mirror analyzer and a static electron gum for Auger spectroscopy. An image analysis system capable of acquiring the pulsed diffraction patterns was assembled and used in analysis of picosecond laser heated surfaces. A large set of time-resolved experiments were conducted to study the thermal response of Pb(110) to picosecond laser heating. The surface Debye-Waller effect was used to time-resolve the evolution of surface temperature. This provided us with a picosecond time-resolved surface lattice temperature probe. Results for laser fluences below surface <span class="hlt">melting</span> show agreement with a heat-diffusion model. The temperature dependence of the Pb(100) along the (110) and the (001) azimuths using x-ray photoelectron forward scattering of the 4f{sub 7/2} <span class="hlt">core</span>-level photoelectrons confirmed, for the first time, surface <span class="hlt">melting</span> of Pb(100) at temperatures as low as 560 K.</p> <div class="credits"> <p class="dwt_author">Elsayed-Ali, H.E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-08-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_6");' href="#" title="Previous Page"> <img 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href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_9");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">141</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19930026565&hterms=mass+asteroids&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmass%2Basteroids"> <span id="translatedtitle"><span class="hlt">Core</span> formation in asteroids</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The chemical and physical aspects of metal segregation in asteroids are considered. Evidence for the existence of metallic <span class="hlt">cores</span> in asteroids, meteorite parent bodies, and planetesimals and for the amount of <span class="hlt">melting</span> required to form <span class="hlt">cores</span> is reviewed, and the physics of metal segregation is discussed. These considerations lead to the conclusion that about 50 percent of <span class="hlt">melting</span> is required for metal to drain away and form a <span class="hlt">core</span>. It is pointed out that such high amounts of <span class="hlt">melting</span> were not always attained in asteroids, indicating that many asteroids might consist of partially differentiated silicates and metallic masses that did not segregate to a <span class="hlt">core</span>. It is suggested that S asteroids might represent such partially differentiated bodies.</p> <div class="credits"> <p class="dwt_author">Taylor, G. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">142</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60714087"> <span id="translatedtitle">Supplementary documentation for an Environmental Impact Statement regarding the Pantex Plant: dispersion analysis for <span class="hlt">postulated</span> accidents</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This report documents work performed in support of preparation of an Environmental Impact Statement (EIS) regarding the Department of Energy (DOE) Pantex Plant near Amarillo, Texas. The report covers the calculation of atmospheric dispersion and deposition of plutonium following <span class="hlt">postulated</span> nonnuclear detonations of nuclear weapons. Downwind total integrated air concentrations and ground deposition values for each <span class="hlt">postulated</span> accident are presented.</p> <div class="credits"> <p class="dwt_author">J. M. Dewart; B. M. Bowen; J. C. Elder</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">143</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5317483"> <span id="translatedtitle">Liquid metal reactions under <span class="hlt">postulated</span> accident conditions for fission and fusion reactors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Sodium and lithium reactions are considered in the context of a <span class="hlt">postulated</span> breach of a coolant boundary. Specific topics addressed are coolant-atmosphere and coolant-material reactions which may contribute to the overall consequence of a <span class="hlt">postulated</span> accident scenario, and coolant reaction extinguishment and effluent control which may be desirable for containment of the spilled coolant.</p> <div class="credits"> <p class="dwt_author">Muhlestein, L.D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">144</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61351264"> <span id="translatedtitle">Study of the regulatory position on <span class="hlt">postulated</span> pipe rupture location criteria: piping reliability project</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This report presents the results of studies on the current regulatory position on <span class="hlt">postulated</span> pipe rupture location criteria and recommends future licensing regulations. The report contains five parts. The first part highlights the current regulatory positions on criteria for <span class="hlt">postulated</span> pipe rupture locations. The second part reviews data on nuclear piping failures related to the failure locations in the piping</p> <div class="credits"> <p class="dwt_author">Woo</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">145</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=PB83119479"> <span id="translatedtitle">The Inductoslag <span class="hlt">Melting</span> Process.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">This bulletin summarizes the results of Bureau of Mines research on the development of the inductoslag <span class="hlt">melting</span> process. Inductoslag <span class="hlt">melting</span> is an induction <span class="hlt">melting</span> technique using a segmented, water-cooled, copper crucible. The process was developed as pa...</p> <div class="credits"> <p class="dwt_author">P. G. Clites</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">146</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26597139"> <span id="translatedtitle">Phenomenological studies on <span class="hlt">melt</span>-coolant interactions in the ALPHA program</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Two series of experiments to investigate <span class="hlt">melt</span>-coolant interactions have been performed as part of the ALPHA program at JAERI. In the <span class="hlt">melt</span> drop steam explosion experiments, <span class="hlt">melt</span> simulating a molten <span class="hlt">core</span> was dropped into a pool of water. Volume fractions of the <span class="hlt">melt</span>, water and steam in the mixing region prior to the occurrence of spontaneous steam explosions were quantified.</p> <div class="credits"> <p class="dwt_author">N. Yamano; Y. Maruyama; T. Kudo; A. Hidaka; J. Sugimoto</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">147</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/20995690"> <span id="translatedtitle">Numerical and Experimental Model Studies on Thermal Hydraulic Behavior of FBR Internal <span class="hlt">Core</span> Catcher Assembly</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary"><span class="hlt">Core</span> Catcher is provided as an in-vessel <span class="hlt">core</span> debris retention device to collect, support, cool and maintain in sub-critical configuration, the generated <span class="hlt">core</span> debris from fuel <span class="hlt">melting</span> due to certain <span class="hlt">postulated</span> Beyond Design Basis Events (BDBE) for Fast Breeder Reactor (FBR). This also acts as a barrier to prevent settling of debris on main vessel and keeps its maximum temperature within acceptable creep range. Heat transfer by natural convection in the <span class="hlt">core</span> catcher assembly has been assessed numerically and through water experiments using geometrically similar configuration. Resistive heating elements are used in experiment as heat source to simulate debris decay heat on <span class="hlt">core</span> catcher. Series of experiments were carried out for two configurations referred as geometry A and geometry B. The later configuration showed enhanced natural convective heat transfer from the lower plenum of the vessel. Temperatures were monitored at critical positions and compared with numerical evaluation. Numerically evaluated flow fields and isotherms are compared with experimental data for specific steady state temperatures on heat source plate. Numerical results are found to be in good agreement with that obtained from experiments. The combined efforts of numerical and experimental work conclude <span class="hlt">core</span> catcher assembly with geometry B to be more suitable. (authors)</p> <div class="credits"> <p class="dwt_author">Sanjay Kumar Das; Anil Kumar Sharma; Jasmin Sudha, A.; Punitha, G.; Lydia, G.; Somayajulu, P.A.; Murthy, S.S.; Malarvizhi, B.; Gopalakrishnan, V.; Harvey, J.; Kasinathan, N.; Rajan, M. [Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">148</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFM.V34C..01H"> <span id="translatedtitle">Pb Partitioning Between Sulfide <span class="hlt">Melt</span> and Silicate <span class="hlt">Melt</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The geochemical behavior of Pb in the earth is replete with enigmas and paradoxes. There is no satisfactory "balanced budget" for Pb amongst the various terrestrial reservoirs, and consequently, no consensus understanding of the U-Th-Pb isotope tracer system, or the behavior of Pb during <span class="hlt">melting</span> processes. Most oceanic mantle <span class="hlt">melts</span> have Pb isotopic compositions that are more radiogenic than Earth's Geochron (First Pb paradox), and all have high and relatively constant Ce/Pb or Nd/Pb ratios compared to "bulk silicate earth" (Third Pb paradox). Yet experimental silicate mineral/<span class="hlt">melt</span> partition coefficients for Ce (or Nd) and Pb differ significantly, so that significant fractionations in Ce/Pb should abound among various mantle reservoirs and various <span class="hlt">melting</span> regimes. New insights into the mantle geochemistry of Pb can be achieved by noting that, due to its chalcophilic nature, Pb will be strongly controlled by sulfide phases during <span class="hlt">melting</span> and differentiation processes, as well as possible large scale sequestering of sulfide into the deep mantle or <span class="hlt">core</span> during plate recycling. Here we report results from new experiments on the partitioning of Pb between coexisting sulfide and silicate <span class="hlt">melts</span> at upper mantle conditions, providing a quantitative basis for evaluating the role of sulfide in controlling the geochemical behavior of Pb. Experiments were carried out on a 10:1 mix of natural MORB and FeS, doped with Pb, in a solid-medium piston-cylinder device. Starting materials were placed in a San Carlos olivine-lined Ni capsule, with a solid magnetite-wüstite buffer, that was pressure sealed. Run products are homogeneous basalt glass and spherical sulfide blebs up to 250?m in diameter. Pb was analyzed by laser ablation ICP-MS (100x100?m area rastered with a 40?m spot), using 57Fe as an internal standard. Standards were NIST 611 glass and synthetic FeS doped with 1065 ppm Pb. Matrix effects on Pb/Fe ion production in the silicate and sulfide standards were small (<8%). Major elements were determined by electron microprobe. The sulfide <span class="hlt">melt</span>-silicate <span class="hlt">melt</span> partition coefficient determined for Pb at 1 GPa and 1300°C is 37.7 ± 2.8 (±1 se, all known uncertainties propagated). Assuming a bulk earth peridotite S content of 250 ppm, and corresponding modal sulfide abundance of 0.069 wt.%, nearly 90% of the Pb budget will be contained in the sulfide. We used a non-modal fractional aggregated <span class="hlt">melting</span> model to assess the behavior of the canonical ratios Ce/Pb and Nd/Pb during <span class="hlt">melting</span> of a "bulk earth" peridotite (0-4% garnet facies <span class="hlt">melt</span>, followed by 4- 10% spinel facies <span class="hlt">melt</span>; S saturation in the <span class="hlt">melt</span> was increased from 1000 ppm at start of <span class="hlt">melting</span> to 1400 ppm at 10% <span class="hlt">melt</span>. Resulting modal sulfide abundance decreases from 0.069% at start of <span class="hlt">melting</span> to 0.036% at 10% <span class="hlt">melt</span>). With our 1 GPa partition coefficient, the Nd/Pb ratio of the <span class="hlt">melt</span> is constant within 10% over the whole range of <span class="hlt">melting</span>. More generally, there is always a combination of partition coefficient and initial S values that produces a virtually constant <span class="hlt">melt</span> Nd/Pb ratio, thus satisfying the Hofmann et al. (1986) observation of constant Ce/Pb in all OIB and MORB. Even significant variations in initial S (200-300 ppm) or partition coefficient (30-50) produce less scatter in Nd/Pb (± 20%) than is observed in the oceanic basalt data set. On the other hand, invariant Nd/Pb ratios during <span class="hlt">melting</span> still accurately reflect the initial source ratio, so that the "Third Pb Paradox" is alive and well! This implies that the mantle sources of OIB and MORB are characterized by significant depletions in Pb, likely due to long-term sequestering of Pb-bearing sulfide into the deep mantle or <span class="hlt">core</span>. This process provides an explanation for the "First Pb Paradox" as well.</p> <div class="credits"> <p class="dwt_author">Hart, S.; Gaetani, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">149</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1997Icar..127..408P"> <span id="translatedtitle">A Reevaluation of Impact <span class="hlt">Melt</span> Production</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The production of <span class="hlt">melt</span> and vapor is an important process in impact cratering events. Because significant <span class="hlt">melting</span> and vaporization do not occur in impacts at velocities currently achievable in the laboratory, a detailed study of the production of <span class="hlt">melt</span> and vapor in planetary impact events is carried out with hydrocode simulations. Sandia's two-dimensional axisymmetric hydrocode CSQ was used to estimate the amount of <span class="hlt">melt</span> and vapor produced for widely varying initial conditions: 10 to 80 km/sec for impact velocity, 0.2 to 10 km for the projectile radius. Runs with different materials demonstrate the material dependency of the final result. These results should apply to any size projectile (for given impact velocity and material), since the results can be dynamically scaled so long as gravity is unimportant in affecting the early-time flow. In contrast with the assumptions of previous analytical models, a clear difference in shape, impact-size dependence, and depth of burial has been found between the <span class="hlt">melt</span> regions and the isobaric <span class="hlt">core</span>. In particular, the depth of the isobaric <span class="hlt">core</span> is not a good representation of the depth of the <span class="hlt">melt</span> regions, which form deeper in the target. While near-surface effects cause the computed <span class="hlt">melt</span> region shapes to look like "squashed spheres" the spherical shape is still a good analytical analog. One of the goals of <span class="hlt">melt</span> production studies is to find proper scaling laws to infer <span class="hlt">melt</span> production for any impact event of interest. We tested the point source limit scaling law for <span class="hlt">melt</span> volumes (? = 0.55-0.6) proposed by M. D. Bjorkman and K. A. Holsapple (1987, Int. J. Impact Eng.5, 155-163). Our results indicate that the point source limit concept does not apply to <span class="hlt">melt</span> and vapor production. Rather, <span class="hlt">melt</span> and vapor production follows an energy scaling law (? = 0.67), in good agreement with previous results of T. J. Ahrens and J. D. O'Keefe [1977, in Impact and Explosion Cratering(D. J. Roddy, R. O. Pepin, and R. B. Merrill, Eds.), pp. 639-656, Pergamon Press, Elmsford, NY]. Finally we tested the accuracy of our <span class="hlt">melt</span> production calculation against a terrestrial dataset compiled by R. A. F. Grieve and M. J. Cintala (1992, Meteorities27, 526-538). The hydrocode <span class="hlt">melt</span> volumes are in good agreement with the estimated volumes of that set of terrestrial craters on crystalline basements. At present there is no good model for <span class="hlt">melt</span> production from impact craters on sedimentary targets.</p> <div class="credits"> <p class="dwt_author">Pierazzo, E.; Vickery, A. M.; Melosh, H. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">150</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10102825"> <span id="translatedtitle">MACCS usage at Rocky Flats Plant for consequence analysis of <span class="hlt">postulated</span> accidents</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The MELCOR Accident Consequence Code System (MACCS) has been applied to the radiological consequence assessment of potential accidents from a non-reactor nuclear facility. MACCS has been used in a variety of applications to evaluate radiological dose and health effects to the public from <span class="hlt">postulated</span> plutonium releases and from <span class="hlt">postulated</span> criticalities. These applications were conducted to support deterministic and probabilistic accident analyses for safety analyses for safety analysis reports, radiological sabotage studies, and other regulatory requests.</p> <div class="credits"> <p class="dwt_author">Foppe, T.L.; Peterson, V.L.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">151</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60547502"> <span id="translatedtitle">Fragmentation and quench behavior of corium <span class="hlt">melt</span> streams in water</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The interaction of molten <span class="hlt">core</span> materials with water has been investigated for the pour stream mixing mode. This interaction plays a crucial role during the later stages of in-vessel <span class="hlt">core</span> <span class="hlt">melt</span> progression inside a light water reactor such as during the TMI-2 accident. The key issues which arise during the molten <span class="hlt">core</span> relocation include: (i) the thermal attack and possible</p> <div class="credits"> <p class="dwt_author">B. W. Spencer; K. Wang; C. A. Blomquist; L. M. McUmber; J. P. Schneider</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">152</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60478741"> <span id="translatedtitle">Rod bundle thermal-hydraulic and <span class="hlt">melt</span> progression analysis of CORA severe fuel damage experiments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">An integral, fast-running computational model is developed to simulate the thermal-hydraulic and <span class="hlt">melt</span> progression behavior in a nuclear reactor rod bundle under severe fuel damage conditions. This consists of the submodels for calculating steaming from the <span class="hlt">core</span>, hydrogen formation, heat transfer in and out of the <span class="hlt">core</span>, cooling from <span class="hlt">core</span> spray or injection, and, most importantly, fuel <span class="hlt">melting</span>, relocation, and</p> <div class="credits"> <p class="dwt_author">Suh</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">153</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE86004051"> <span id="translatedtitle"><span class="hlt">Melting</span> of Amorphous Si.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The prediction by Turnbull and his colleagues that amorphous Si and Ge undergo first order <span class="hlt">melting</span> transitions at temperatures T/sub al/ substantially beneath the crystalline <span class="hlt">melting</span> temperature T/sub cl/ has stimulated much work. Structural, calorimetric...</p> <div class="credits"> <p class="dwt_author">J. M. Poate P. S. Peercy M. O. Thompson</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">154</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1996LPI....27..881M"> <span id="translatedtitle">Metal-Sulfide <span class="hlt">Melt</span> Non-Interconnectivity in Silicates, Even at High Pressure, High Temperature, and High <span class="hlt">Melt</span> Fractions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have investigated the textural microstructure of iron-nickel-sulfur <span class="hlt">melts</span> in contact with olivine, pyroxene, and the modified-spinel polymorph of olivine. The experiments were conducted at 1500 degrees C and pressures ranging from 1 to 17 GPa. For compositions more metal-rich than the monosulfide, including the eutectic composition, the metal sulfide <span class="hlt">melt</span> has a dihedral angle greater than 60 degrees and does not form an interconnected grain-edge fluid. Increasing pressure does not measurably alter the dihedral angles. Textural evolution results in coarsening of the sulfide <span class="hlt">melt</span> pockets, resulting in large pockets surrounded by many silicate grains and separated from one another by <span class="hlt">melt</span>-free grain edges. Chemical communication between these large pockets is limited to lattice and grain-boundary diffusion. Due to the large interfacial energy between sulfide <span class="hlt">melt</span> and silicates, sulfide <span class="hlt">melts</span> are unable to separate from solid silicate via grain-boundary percolation and remain stranded in isolated <span class="hlt">melt</span> pockets. Sulfide <span class="hlt">melt</span> in excess of the critical <span class="hlt">melt</span> fraction (5-25%) will develop a transient interconnectivity as sulfide collects into larger <span class="hlt">melt</span> pockets and interconnectivity is pinched off. Efficient separation of <span class="hlt">core</span>-forming sulfide <span class="hlt">melts</span> from silicate requires either <span class="hlt">melting</span> of the silicate matrix or a very large fraction of metal-sulfide <span class="hlt">melt</span> (perhaps as large as 40%).</p> <div class="credits"> <p class="dwt_author">Minarik, W. G.; Ryerson, F. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">155</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/231380"> <span id="translatedtitle">Metal-sulfide <span class="hlt">melt</span> non-interconnectivity in silicates, even at high pressure, high temperature, and high <span class="hlt">melt</span> fractions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The authors have investigated the textural microstructure of iron-nickel-sulfur <span class="hlt">melts</span> in contact with olivine, pyroxene, and the modified-spinel polymorph of olivine. The experiments were conducted at 1,500 C and pressures ranging from 1 to 17 GPa. For compositions more metal-rich than the monosulfide, including the eutectic composition, the metal sulfide <span class="hlt">melt</span> has a dihedral angle greater than 60{degree} and does not form an interconnected grain-edge fluid. Increasing pressure does not measurably alter the dihedral angles. Textural evolution results in coarsening of the sulfide <span class="hlt">melt</span> pockets, resulting in large pockets surrounded by many silicate grains and separated from one another by <span class="hlt">melt</span>-free grain edges. Chemical communication between these large pockets is limited to lattice and grain-boundary diffusion. Due to the large interfacial energy between sulfide <span class="hlt">melt</span> and silicates, sulfide <span class="hlt">melts</span> are unable to separate from solid silicate via grain-boundary percolation and remain stranded in isolated <span class="hlt">melt</span> pockets. Sulfide <span class="hlt">melt</span> in excess of the critical <span class="hlt">melt</span> fraction (5--25%) will develop a transient interconnectivity as sulfide collects into larger <span class="hlt">melt</span> pockets and interconnectivity is pinched off. Efficient separation of <span class="hlt">core</span>-forming sulfide <span class="hlt">melts</span> from silicate requires either <span class="hlt">melting</span> of the silicate matrix or a very large fraction of metal-sulfide <span class="hlt">melt</span> (perhaps as large as 40%).</p> <div class="credits"> <p class="dwt_author">Minarik, W.G.; Ryerson, F.J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">156</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6973760"> <span id="translatedtitle">Re-evaluation of superheat conditions <span class="hlt">postulated</span> in NRC Information Notice 84-90</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Information Notice 84-90, ''Main Steam Line Break Effect on Environmental Qualification of Equipment,'' describes a potential problem regarding existing plant analyses and Equipment Qualification (EQ) related to a <span class="hlt">postulated</span> Main Steam Line Break (MSLB) with releases of superheated stream. This notice states that certain methodologies for computing mass and energy releases for a <span class="hlt">postulated</span> MSLB did not account for heat transfer from the steam generator tube bundles if they were uncovered. Due to this potential change in the original environmental analysis, the EQ of various components may not consider the thermal environment which could result from superheated steam. Subsequent technical assessments may determine that the existing qualification basis for equipment/components does not envelop the <span class="hlt">postulated</span> superheat condition. Corrective actions need to be taken to demonstrate that the affected equipment is qualified.</p> <div class="credits"> <p class="dwt_author">Alsammarae, A.; Kruger, D.; Beutel, D.; Spisak, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">157</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19770022839&hterms=Amputee&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAmputee"> <span id="translatedtitle">Application of a <span class="hlt">postulate</span> based control theory for an artificial arm</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The biocontroller, remnant of the natural arm, and feedback elements must be considered in designing a controller for an above elbow artificial arm for amputees. This fundamental <span class="hlt">postulate</span> is used to derive equations for developing the controller, which is shown in block diagrams.</p> <div class="credits"> <p class="dwt_author">Jacobsen, S. C.; Jerard, R. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1975-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">158</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/24026792"> <span id="translatedtitle">Application of Hammond's <span class="hlt">Postulate</span>. An Activity for Guided Discovery Learning in Organic Chemistry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper describes an activity that promotes the more active involvement of organic chemistry students in their learning. In this activity, students are given product distributions and other relevant experimental data concerning the free radical chlorination and bromination of propane. Students are guided in the use of Hammond's <span class="hlt">postulate</span> to predict transition-state structures and to provide a rationale for the</p> <div class="credits"> <p class="dwt_author">J. E. Meany; Vicky Minderhout; Y. Pocker</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">159</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/24264777"> <span id="translatedtitle">Fitting Straight Lines with Replicated Observations by Linear Regression: The Least Squares <span class="hlt">Postulates</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The results obtained by statistical techniques are valid if the assumed conditions are satisfied. Fitting straight lines with replicated observations by linear regression is considered in this article paying special attention to the compliance of the least squares <span class="hlt">postulates</span>. Normality, robustness, independence, abscissa free from error, and proper weights are contemplated sequentially in this article. A detailed consideration of multiple</p> <div class="credits"> <p class="dwt_author">Ana Sayago; Maravillas Boccio; Agustin Asuero</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">160</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AIPC.1558.1943V"> <span id="translatedtitle">Are the non equilibrium thermodynamics <span class="hlt">postulates</span> necessary in modeling coating formation by drying?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this work it is shown that it is necessary to apply the non equilibrium thermodynamics <span class="hlt">postulates</span> in Fickian multi-component diffusion appearing in coating formation by drying. More specifically, two cases of solvent(s) evaporation from a ternary polymer solution were examined. The first case assumes given diffusion coefficients while in the second case the non-equilibrium thermodynamics <span class="hlt">postulates</span> such as the Onsager Reciprocal Relations (ORR) and the quasi equilibrium <span class="hlt">postulate</span> (Gibbs-Duhem equation) were applied. The coating drying was modeled as a coupled heat and mass problem with a moving boundary. The Galerkin Finite Element method was applied to numerically solve the drying problem. It was shown that the inclusion of quasi equilibrium <span class="hlt">postulates</span> in calculating the ternary diffusion coefficients could explain the discrepancy of negative concentrations in the given diffusion coefficients case observed even if the restrictions of the second thermodynamic law are satisfied. It is believed that this work could have applications such as modeling coating formation by drying.</p> <div class="credits"> <p class="dwt_author">Verros, George D.; Xentes, George K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_7");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return 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showDiv("page_10");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">161</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=172879"> <span id="translatedtitle">Sequence-based identification of microbial pathogens: a reconsideration of Koch's <span class="hlt">postulates</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Over 100 years ago, Robert Koch introduced his ideas about how to prove a causal relationship between a microorganism and a disease. Koch's <span class="hlt">postulates</span> created a scientific standard for causal evidence that established the credibility of microbes as pathogens and led to the development of modern microbiology. In more recent times, Koch's <span class="hlt">postulates</span> have evolved to accommodate a broader understanding of the host-parasite relationship as well as experimental advances. Techniques such as in situ hybridization, PCR, and representational difference analysis reveal previously uncharacterized, fastidious or uncultivated, microbial pathogens that resist the application of Koch's original <span class="hlt">postulates</span>, but they also provide new approaches for proving disease causation. In particular, the increasing reliance on sequence-based methods for microbial identification requires a reassessment of the original <span class="hlt">postulates</span> and the rationale that guided Koch and later revisionists. Recent investigations of Whipple's disease, human ehrlichiosis, hepatitis C, hantavirus pulmonary syndrome, and Kaposi's sarcoma illustrate some of these issues. A set of molecular guidelines for establishing disease causation with sequence-based technology is proposed, and the importance of the scientific concordance of evidence in supporting causal associations is emphasized.</p> <div class="credits"> <p class="dwt_author">Fredericks, D N; Relman, D A</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">162</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=SPORES&id=EJ558809"> <span id="translatedtitle">Fun Microbiology: Using a Plant Pathogenic Fungus To Demonstrate Koch's <span class="hlt">Postulates</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Describes an experiment using a plant pathogenic fungus in which students learn to follow aseptic techniques, grow and produce spores of a fungus, use a hemacytometer for enumerating spores, prepare serial dilutions, grow and inoculate plants, isolate a pure culture using agar streak plates, and demonstrate the four steps of Koch's <span class="hlt">postulates</span>.…</p> <div class="credits"> <p class="dwt_author">Mitchell, James K.; Orsted, Kathy M.; Warnes, Carl E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">163</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54555787"> <span id="translatedtitle">Oceans of Water in the Earth's <span class="hlt">core</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">While the debate on the chemical composition of the outer <span class="hlt">core</span> continues unabated, it is essential that we consider water as an important <span class="hlt">core</span> substance for the reasons that it is abundant and suitably light to decrease the density and <span class="hlt">melting</span> temperature of iron. Furthermore, if water is indeed stored in the <span class="hlt">core</span>, it should provide a suitable source for</p> <div class="credits"> <p class="dwt_author">S. K. Saxena; L. Dubrovinsky; S. Rekhi; Z. Wang; G. Shen</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">164</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10185682"> <span id="translatedtitle">The rock <span class="hlt">melting</span> approach to drilling</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">During the early and mid-1970`s the Los Alamos National Laboratory demonstrated practical applications of drilling and <span class="hlt">coring</span> using an electrically-heated graphite, tungsten, or molybdenum penetrator that <span class="hlt">melts</span> a hole as it is slowly pushed through the rock or soil. The molten material consolidates into a rugged glass lining that prevents hole collapse; minimizes the potential for cross-flow, lost circulation, or the release of hazardous materials without casing operations; and produces no cuttings in porous or low density (<1.7 g/cc) formations. Because there are no drilling fluids required, the rock <span class="hlt">melting</span> approach reduces waste handling, treatment and disposal. Drilling by rock <span class="hlt">melting</span> has been demonstrated to depths up to 30 m in caliche, clay, alluvium, cobbles, sand, basalt, granite, and other materials. Penetrating large cobbles without debris removal was achieved by thermal stress fracturing and lateral extrusion of portions of the rock <span class="hlt">melt</span> into the resulting cracks. Both horizontal and vertical holes in a variety of diameters were drilled in these materials using modular, self-contained field units that operate in remote areas. Because the penetrator does not need to rotate, steering by several simple approaches is considered quite feasible. <span class="hlt">Melting</span> is ideal for obtaining <span class="hlt">core</span> samples in alluvium and other poorly consolidated soils since the formed-in-place glass liner stabilizes the hole, encapsulates volatile or hazardous material, and recovers an undisturbed <span class="hlt">core</span>. Because of the relatively low thermal conductivity of rock and soil materials, the heat-affected zone beyond the <span class="hlt">melt</span> layer is very small, <1 inch thick. Los Alamos has begun to update the technology and this paper will report on the current status of applications and designs for improved drills.</p> <div class="credits"> <p class="dwt_author">Cort, G.E.; Goff, S.J.; Rowley, J.C.; Neudecker, J.W. Jr.; Dreesen, D.S.; Winchester, W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">165</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=MAGNESIUM&id=EJ1015670"> <span id="translatedtitle">The Relationship between Lattice Enthalpy and <span class="hlt">Melting</span> Point in Magnesium and Aluminium Oxides. Science Notes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">This "Science Note" presents a study by Christopher Talbot and Lydia Yap, who teach IB Chemistry at Anglo-Chinese School (Independent), Republic of Singapore, to pre-university students. Pre-university students may <span class="hlt">postulate</span> the correlation between the magnitude of the lattice enthalpy compound and its <span class="hlt">melting</span> point, since both…</p> <div class="credits"> <p class="dwt_author">Talbot, Christopher; Yap, Lydia</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">166</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001JChEd..78..204M"> <span id="translatedtitle">Application of Hammond's <span class="hlt">Postulate</span>. An Activity for Guided Discovery Learning in Organic Chemistry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper describes an activity that promotes the more active involvement of organic chemistry students in their learning. In this activity, students are given product distributions and other relevant experimental data concerning the free radical chlorination and bromination of propane. Students are guided in the use of Hammond's <span class="hlt">postulate</span> to predict transition-state structures and to provide a rationale for the relationship between selectivity and reactivity in these and other reactions. In carrying out the skill exercises, students must also review and apply some of the concepts learned in their general chemistry courses. Because of the wide variety of applications of the Hammond <span class="hlt">postulate</span>, we believe that this activity, along with the associated discussions, represents an effective teaching/learning model that is particularly useful at the early stages of an organic chemistry series.</p> <div class="credits"> <p class="dwt_author">Meany, J. E.; Minderhout, Vicky; Pocker, Y.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">167</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/175561"> <span id="translatedtitle">DYNAMICS OF HEAT TRANSFER IN THE <span class="hlt">MELT</span> POOL AT NUCLEAR SEVERE ACCIDENT CONDITIONS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Prediction of thermal loads on nuclear reactor vessel lower plenum after <span class="hlt">core</span> <span class="hlt">melting</span> and relocation during a severe accident requires knowledge about the <span class="hlt">core</span> <span class="hlt">melt</span> behavior, especially the circulation pattern. To analyze the heat transfer dynamics on t he lower plenum walls, two-dimensional numerical simulations of a fluid flow with internal heat generation were performed for Rayleigh numbers 10 6,</p> <div class="credits"> <p class="dwt_author">Andrej Horvat; Ivo Kljenak; Jure Marn</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">168</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/dg9724863381r4v6.pdf"> <span id="translatedtitle">The prelude of the end-Permian mass extinction predates a <span class="hlt">postulated</span> bolide impact</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The mass extinction at the Permian–Triassic Boundary (PTB) is said to have been abrupt and probably caused by an extraterrestrial\\u000a impact. However, evidence from the Global Stratotype Section and Point (GSSP) of the base of the Induan at Meishan, China,\\u000a shows that the biotic crisis began prior to the level, in beds 25 and 26 at which the <span class="hlt">postulated</span> impact</p> <div class="credits"> <p class="dwt_author">Hongfu Yin; Qinglai Feng; Aymon Baud; Shucheng Xie; Mike J. Benton; Xulong Lai; David J. Bottjer</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">169</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5300514"> <span id="translatedtitle">Born's <span class="hlt">postulate</span> and reconstruction of the phi-function in nonrelativistic quantum mechanics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A continuous family of self-adjoint operators is constructed such that their measurement data are insufficient to reproduce uniquely via Born's <span class="hlt">postulate</span> the underlying quantum state. Moreover, no pair of operators has a common invariant subspace. This rejects a conjecture given by Moroz. On the other hand, strengthening results obtained by Kreinovitch, it is shown that already one special potential and the related localization measurement data at different moments of time can guarantee the uniqueness of reconstruction.</p> <div class="credits"> <p class="dwt_author">Wiesbrock, H.W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">170</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1987IJTP...26.1175W"> <span id="translatedtitle">Born's <span class="hlt">Postulate</span> and Reconstruction of the ?-Function in Nonrelativistic Quantum Mechanics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A continuous family of self-adjoint operators is constructed such that their measurement data are insufficient to reproduce uniquely via Born's <span class="hlt">postulate</span> the underlying quantum state. Moreover, no pair of operators has a common invariant subspace. This rejects a conjecture given by Moroz. On the other hand, strengthening results obtained by Kreinovitch, it is shown that already one special potential and the related localization measurement data at different moments of time can guarantee the uniqueness of reconstruction.</p> <div class="credits"> <p class="dwt_author">Wiesbrock, H.-W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">171</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5528039"> <span id="translatedtitle">TMI-2 <span class="hlt">core</span> damage</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">On March 28, 1979, the Unit 2 reactor at Three Mile Island (TMI) underwent an accident that resulted in severe damage to the reactor's <span class="hlt">core</span>. A <span class="hlt">core</span> damage examination program is essential to understanding the unique conditions and for developing work plans and tools in advance of each portion of the reactor disassembly /defueling effort. To characterize the conditions, the reactor vessel was divided into five regions requiring varied approaches to defueling, because each contains a unique configuration and formation: (1) upper <span class="hlt">core</span> region, (2) mid-<span class="hlt">core</span> region, (3) lower <span class="hlt">core</span> region, (4) lower <span class="hlt">core</span> support assembly region, and (5) lower heat region. The original <span class="hlt">core</span> inventory included approx. 93,000 kg of fuel and 35,000 kg of structural and neutron absorber material for a total of 128,250 kg. Assuming that 90% of the hydrogen generated during the accident was due to reduction of the coolant and accounting for portions of the upper plenum structure that <span class="hlt">melted</span>, the total postaccident <span class="hlt">core</span> material comes to approx. 131,850 kg. As of January 9, 1987, 29,000 kg of the material had been defueled.</p> <div class="credits"> <p class="dwt_author">Eidam, G.R.; Worku, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">172</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N8415271"> <span id="translatedtitle">Hot <span class="hlt">Melt</span> Recharge System.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">A package assembly is described for precisely positioning a charge of hot <span class="hlt">melt</span> adhesive onto an attachment pad or a point of use. The adhesive is heated to softening or <span class="hlt">melt</span> temperature (280 F - 325 F) and thereafter cooled to resolidifying temperature. A...</p> <div class="credits"> <p class="dwt_author">D. J. Progar</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">173</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N8226464"> <span id="translatedtitle">Hot <span class="hlt">Melt</span> Recharge System.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">A package assembly for precisely positioning a charge of hot <span class="hlt">melt</span> adhesive onto an attachment pad or point of use is described. The adhesive is heated to softening or <span class="hlt">melt</span> temperature (280 F to 325 F) and thereafter cooled to resolidifying temperature. A ...</p> <div class="credits"> <p class="dwt_author">D. J. Progar</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">174</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/9780873552554.9"> <span id="translatedtitle">Is It <span class="hlt">Melting</span>?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">The purpose of this assessment probe is to elicit students' ideas about the physical process of <span class="hlt">melting</span>. The probe is designed to find out if students recognize <span class="hlt">melting</span> as a change in state from solid to liquid that involves one substance or if they confuse it with other physical changes, such as dissolving, that involve two substances.</p> <div class="credits"> <p class="dwt_author">Eberle, Francis; Farrin, Lynn; Keeley, Page</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">175</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://news.bbc.co.uk/2/hi/americas/3172572.stm"> <span id="translatedtitle"><span class="hlt">Melting</span> Glaciers Threaten Peru</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Thousands of people in the Andes mountains of Peru are having their lives affected in both a practical and cultural way by climate change, which is causing the region's glaciers to <span class="hlt">melt</span>. This document explores the causes of the glacial <span class="hlt">melt</span> and its impacts on the local cultures.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2003-10-09</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">176</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013PhRvB..87m4103S"> <span id="translatedtitle"><span class="hlt">Melting</span> of graphene clusters</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Density-functional tight-binding and classical molecular dynamics simulations are used to investigate the structural deformations and <span class="hlt">melting</span> of planar carbon nanoclusters CN with N=2-55. The minimum-energy configurations for different clusters are used as starting configurations for the study of the temperature effects on the bond breaking and rotation in carbon lines (N<6), carbon rings (5<N<19), and graphene nanoflakes. The larger the rings (graphene nanoflakes) the higher the transition temperature (<span class="hlt">melting</span> point) with ring-to-line (perfect-to-defective) transition structures. The <span class="hlt">melting</span> point was obtained by using the bond energy, the Lindemann criteria, and the specific heat. We found that hydrogen-passivated graphene nanoflakes (CNHM) have a larger <span class="hlt">melting</span> temperature with a much smaller dependence on size. The edges in the graphene nanoflakes exhibit several different metastable configurations (isomers) during heating before <span class="hlt">melting</span> occurs.</p> <div class="credits"> <p class="dwt_author">Singh, Sandeep Kumar; Neek-Amal, M.; Peeters, F. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">177</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/787733"> <span id="translatedtitle">Development of the BWR Dry <span class="hlt">Core</span> Initial and Boundary Conditions for the SNL XR2 Experiments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The objectives of the Boiling Water Reactor Experimental Analysis and Model Development for Severe Accidents (BEAMD) Program at the Oak Ridge National Laboratory (ORNL) are: (1) the development of a sound quantitative understanding of boiling water reactor (BWR) <span class="hlt">core</span> <span class="hlt">melt</span> progression; this includes control blade and channel box effects, metallic <span class="hlt">melt</span> relocation and possible blockage formation under severe accident conditions, and (2) provision of BWR <span class="hlt">melt</span> progression modeling capabilities in SCDAP/RELAP5 (consistent with the BWR experimental data base). This requires the assessment of current modeling of BWR <span class="hlt">core</span> <span class="hlt">melt</span> progression against the expanding BWR data base. Emphasis is placed upon data from the BWR tests in the German CORA test facility and from the ex-reactor experiments [Sandia National Laboratories (SNL)] on metallic <span class="hlt">melt</span> relocation and blockage formation in BWRs, as well as upon in-reactor data from the Annular <span class="hlt">Core</span> Research Reactor (ACRR) DF-4 BWR test (conducted in 1986 at SNL). The BEAMD Program is a derivative of the BWR Severe Accident Technology Programs at ORNL. The ORNL BWR programs have studied <span class="hlt">postulated</span> severe accidents in BWRs and have developed a set of models specific to boiling water reactor response under severe accident conditions. These models, in an experiment-specific format, have been successfully applied to both pretest and posttest analyses of the DF-4 experiment, and the BWR severe fuel damage (SFD) experiments performed in the CORA facility at the Kernforschungszentrum Karlsruhe (KfK) in Germany, resulting in excellent agreement between model prediction and experiment. The ORNL BWR models have provided for more precise predictions of the conditions in the BWR experiments than were previously available. This has provided a basis for more accurate interpretation of the phenomena for which the experiments are performed. The experiment-specific models, as used in the ORNL DF-4 and CORA BWR experimental analyses, also provide a basis for the efficient development of new models for phenomena such as materials interaction; and these validated phenomenological models (from the results of the experiments) then may be incorporated in the systems-level codes (MELCOR and SCDAP/RELAP5).</p> <div class="credits"> <p class="dwt_author">Ott, L.J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">178</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1994CoMP..118..157W"> <span id="translatedtitle">Compressibility of titanosilicate <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The effect of composition on the relaxed adiabatic bulk modulus (K0) of a range of alkali- and alkaline earth-titanosilicate [X{2/n/n+}TiSiO5 (X=Li, Na, K, Rb, Cs, Ca, Sr, Ba)] <span class="hlt">melts</span> has been investigated. The relaxed bulk moduli of these <span class="hlt">melts</span> have been measured using ultrasonic interferometric methods at frequencies of 3, 5 and 7 MHz in the temperature range of 950 to 1600°C (0.02 Pa s < ?s < 5 Pa s). The bulk moduli of these <span class="hlt">melts</span> decrease with increasing cation size from Li to Cs and Ca to Ba, and with increasing temperature. The bulk moduli of the Li-, Na-, Ca- and Ba-bearing metasilicate <span class="hlt">melts</span> decrease with the addition of both TiO2 and SiO2 whereas those of the K-, Rb- and Cs-bearing <span class="hlt">melts</span> increase. Linear fits to the bulk modulus versus volume fraction of TiO2 do not converge to a common compressibility of the TiO2 component, indicating that the structural role of TiO2 in these <span class="hlt">melts</span> is dependent on the identity of the cation. This proposition is supported by a number of other property data for these and related <span class="hlt">melt</span> compositions including heat capacity and density, as well as structural inferences from X-ray absorption spectroscopy (XANES). The compositional dependence of the compressibility of the TiO2 component in these <span class="hlt">melts</span> explains the difficulty incurred in previous attempts to incorporate TiO2 in calculation schemes for <span class="hlt">melt</span> compressibility. The empirical relationship K?V-4/3 for isostructural materials has been used to evaluate the compressibility-related structural changes occurring in these <span class="hlt">melts</span>. The alkali metasilicate and disilicate <span class="hlt">melts</span> are isostructural, independent of the cation. The addition of Ti to the metasilicate composition (i.e. X2TiSiO5), however, results in a series of <span class="hlt">melts</span> which are not isostructural. The alkaline-earth metasilicate and disilicate compositions are not isostructural, but the addition of Ti to the metasilicate compositions (i.e. XTiSiO5) would appear, on the basis of modulus-volume systematics, to result in the <span class="hlt">melts</span> becoming isostructural with respect to compressibility.</p> <div class="credits"> <p class="dwt_author">Webb, Sharon L.; Dingwell, Donald B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">179</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60716017"> <span id="translatedtitle">Supplementary documentation for an Environmental Impact Statement regarding the Pantex Plant: decontamination methods and cost estimates for <span class="hlt">postulated</span> accidents</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This report documents work performed in support of preparation of an Environmental Impact Statement regarding the Department of Energy's Pantex Plant near Amarillo, Texas. Methodology and costs for decontamination following a <span class="hlt">postulated</span> nonnuclear detonation of a nuclear weapon are presented for three land use categories: agricultural, surburban, and commercial. Seven <span class="hlt">postulated</span> releases of plutonium are addressed: three at the Pantex</p> <div class="credits"> <p class="dwt_author">Wenzel</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">180</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48928642"> <span id="translatedtitle">Rise in frequency of surface <span class="hlt">melting</span> at Siple Dome through the Holocene: Evidence for increasing marine influence on the climate of West Antarctica</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A new <span class="hlt">melt</span> layer history from Siple Dome, West Antarctica, indicates notable late-Holocene summertime warming. Visual stratigraphic analyses of the 1004-m ice <span class="hlt">core</span> identified 62 years with <span class="hlt">melt</span> layers. <span class="hlt">Melting</span> events began around 11.7 ka, followed by a period of no <span class="hlt">melting</span> from 8.8–6.6 ka. <span class="hlt">Melt</span> layer frequency increased from 6.6 ka to the present, with the 1000-year-average <span class="hlt">melt</span> layer</p> <div class="credits"> <p class="dwt_author">Sarah B. Das; Richard B. Alley</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_8");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_11");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">181</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/10140058"> <span id="translatedtitle">A 275 year ice-<span class="hlt">core</span> record from Akademii Nauk ice cap, Severnaya Zemlya, Russian Arctic</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Between 1999 and 2001, a 724 m long ice <span class="hlt">core</span> was drilled on Akademii Nauk, the largest glacier on Severnaya Zemlya, Russian Arctic. The drilling site is located near the summit. The <span class="hlt">core</span> is characterized by high <span class="hlt">melt</span>-layer content. The <span class="hlt">melt</span> layers are caused by <span class="hlt">melting</span> and even by rain during the summer. We present high-resolution data of density, electrical</p> <div class="credits"> <p class="dwt_author">Diedrich Fritzsche; Rainer Schütt; Hanno Meyer; Heinz Miller; Frank Wilhelms; Thomas Opel; Lev M. Savatyugin</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">182</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5465164"> <span id="translatedtitle">Degraded <span class="hlt">core</span> modeling in MELCOR</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A package of phenomenological models has been developed for the MELCOR code system to calculate the thermal response of structures in the <span class="hlt">core</span> and lower plenum of an LWR during a severe accident. This package treats all important modes of heat transfer within the <span class="hlt">core</span>, as well as oxidation, debris formation, and relocation of <span class="hlt">core</span> and structural materials during <span class="hlt">melting</span>, candling, and slumping. Comparison of MELCOR and MARCON calculations for the Browns Ferry BWR primary system shows many areas of agreement during the early stages of <span class="hlt">core</span> heatup and oxidation, but very large differences at later times. Many of these differences are attributed to the effects of candling predicted by MELCOR and the lack of any mechanistic candling or debris relocation models in MARCON. The <span class="hlt">melting</span> and slumping behavior calculated by MELCOR is in qualitative agreement with our current understanding of the processes involved.</p> <div class="credits"> <p class="dwt_author">Summers, R.M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">183</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6213539"> <span id="translatedtitle">Development of a fuel-rod simulator and small-diameter thermocouples for high-temperature, high-heat-flux tests in the Gas-Cooled Fast Reactor <span class="hlt">Core</span> Flow Test Loop</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The <span class="hlt">Core</span> Flow Test Loop was constructed to perform many of the safety, <span class="hlt">core</span> design, and mechanical interaction tests in support of the Gas-Cooled Fast Reactor (GCFR) using electrically heated fuel rod simulators (FRSs). Operation includes many off-normal or <span class="hlt">postulated</span> accident sequences including transient, high-power, and high-temperature operation. The FRS was developed to survive: (1) hundreds of hours of operation at 200 W/cm/sup 2/, 1000/sup 0/C cladding temperature, and (2) 40 h at 40 W/cm/sup 2/, 1200/sup 0/C cladding temperature. Six 0.5-mm type K sheathed thermocouples were placed inside the FRS cladding to measure steady-state and transient temperatures through clad <span class="hlt">melting</span> at 1370/sup 0/C.</p> <div class="credits"> <p class="dwt_author">McCulloch, R.W.; MacPherson, R.E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">184</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20090041685&hterms=plug-in&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2522plug-in%2522"> <span id="translatedtitle"><span class="hlt">Core</span>-Cutoff Tool</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A tool makes a cut perpendicular to the cylindrical axis of a <span class="hlt">core</span> hole at a predetermined depth to free the <span class="hlt">core</span> at that depth. The tool does not damage the surrounding material from which the <span class="hlt">core</span> was cut, and it operates within the <span class="hlt">core</span>-hole kerf. <span class="hlt">Coring</span> usually begins with use of a hole saw or a hollow cylindrical abrasive cutting tool to make an annular hole that leaves the <span class="hlt">core</span> (sometimes called the plug ) in place. In this approach to <span class="hlt">coring</span> as practiced heretofore, the <span class="hlt">core</span> is removed forcibly in a manner chosen to shear the <span class="hlt">core</span>, preferably at or near the greatest depth of the <span class="hlt">core</span> hole. Unfortunately, such forcible removal often damages both the <span class="hlt">core</span> and the surrounding material (see Figure 1). In an alternative prior approach, especially applicable to toxic or fragile material, a <span class="hlt">core</span> is formed and freed by means of milling operations that generate much material waste. In contrast, the present tool eliminates the damage associated with the hole-saw approach and reduces the extent of milling operations (and, hence, reduces the waste) associated with the milling approach. The present tool (see Figure 2) includes an inner sleeve and an outer sleeve and resembles the hollow cylindrical tool used to cut the <span class="hlt">core</span> hole. The sleeves are thin enough that this tool fits within the kerf of the <span class="hlt">core</span> hole. The inner sleeve is attached to a shaft that, in turn, can be attached to a drill motor or handle for turning the tool. This tool also includes a cutting wire attached to the distal ends of both sleeves. The cutting wire is long enough that with sufficient relative rotation of the inner and outer sleeves, the wire can cut all the way to the center of the <span class="hlt">core</span>. The tool is inserted in the kerf until its distal end is seated at the full depth. The inner sleeve is then turned. During turning, frictional drag on the outer <span class="hlt">core</span> pulls the cutting wire into contact with the <span class="hlt">core</span>. The cutting force of the wire against the <span class="hlt">core</span> increases with the tension in the wire and, hence, with the frictional drag acting on the outer sleeve. As the wire cuts toward the center of the <span class="hlt">core</span>, the inner sleeve rotates farther with respect to the outer sleeve. Once the wire has cut to the center of the <span class="hlt">core</span>, the tool and the <span class="hlt">core</span> can be removed from the hole. The proper choice of cutting wire depends on the properties of the <span class="hlt">core</span> material. For a sufficiently soft <span class="hlt">core</span> material, a nonmetallic monofilament can be used. For a rubber-like <span class="hlt">core</span> material, a metal wire can be used. For a harder <span class="hlt">core</span> material, it is necessary to use an abrasive wire, and the efficiency of the tool can be increased greatly by vacuuming away the particles generated during cutting. For a <span class="hlt">core</span> material that can readily be <span class="hlt">melted</span> or otherwise cut by use of heat, it could be preferable to use an electrically heated cutting wire. In such a case, electric current can be supplied to the cutting wire, from an electrically isolated source, via rotating contact rings mounted on the sleeves.</p> <div class="credits"> <p class="dwt_author">Gheen, Darrell</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">185</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/219260"> <span id="translatedtitle">Modeling and analyses of <span class="hlt">postulated</span> UF{sub 6} release accidents in gaseous diffusion plant</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Computer models have been developed to simulate the transient behavior of aerosols and vapors as a result of a <span class="hlt">postulated</span> accident involving the release of uranium hexafluoride (UF{sub 6}) into the process building of a gaseous diffusion plant. UF{sub 6} undergoes an exothermic chemical reaction with moisture (H{sub 2}O) in the air to form hydrogen fluoride (HF) and radioactive uranyl fluoride (UO{sub 2}F{sub 2}). As part of a facility-wide safety evaluation, this study evaluated source terms consisting of UO{sub 2}F{sub 2} as well as HF during a <span class="hlt">postulated</span> UF{sub 6} release accident in a process building. In the <span class="hlt">postulated</span> accident scenario, {approximately}7900 kg (17,500 lb) of hot UF{sub 6} vapor is released over a 5 min period from the process piping into the atmosphere of a large process building. UO{sub 2}F{sub 2} mainly remains as airborne-solid particles (aerosols), and HF is in a vapor form. Some UO{sub 2}F{sub 2} aerosols are removed from the air flow due to gravitational settling. The HF and the remaining UO{sub 2}F{sub 2} are mixed with air and exhausted through the building ventilation system. The MELCOR computer code was selected for simulating aerosols and vapor transport in the process building. MELCOR model was first used to develop a single volume representation of a process building and its results were compared with those from past lumped parameter models specifically developed for studying UF{sub 6} release accidents. Preliminary results indicate that MELCOR predicted results (using a lumped formulation) are comparable with those from previously developed models.</p> <div class="credits"> <p class="dwt_author">Kim, S.H.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W. [Oak Ridge National Lab., TN (United States); Carter, J.C. [J.C. Carter Associates, Inc., Oak Ridge, TN (United States); Dyer, R.H. [Dyer Enterprises, Oak Ridge, TN (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">186</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://serc.carleton.edu/NAGTWorkshops/oceanography/activities/73296.html"> <span id="translatedtitle"><span class="hlt">Melting</span> ice cubes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Explore how <span class="hlt">melting</span> of ice cubes floating in water is influenced by the salinity of the water. Important oceanographic concepts like density and density driven currents are visualized and can be discussed on the basis of this experiment.</p> <div class="credits"> <p class="dwt_author">Glessmer, Mirjam</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">187</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10125309"> <span id="translatedtitle">Coolability of a control rod which has <span class="hlt">melted</span> and foamed in its septifoil channel</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">During a Loss of Control Rod Cooling (LCRC) event, the control rods which are in the affected septifoil can be <span class="hlt">postulated</span> to <span class="hlt">melt</span>. <span class="hlt">Melting</span> of a control rod which has been irradiated creates a special concern since the entrapped gases expand rapidly and cause the <span class="hlt">melt</span> to manifest itself initially in a foamed state. The foamed material then contacts the septifoil outer housing and the inner septifoil web material, where heat is conducted out of the foamed material. A second concern relating to the foamed <span class="hlt">melt</span> is that its thermal conductivity is greatly reduced from that of the solid material, and also that of the non-foamed liquid. The purpose of this report is to address how, even in the presence of decreased thermal conductivity, the foamed <span class="hlt">melt</span> may aid in cooling the control rod material.</p> <div class="credits"> <p class="dwt_author">Walkowiak, D.A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">188</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3375949"> <span id="translatedtitle">Investigation of reactions <span class="hlt">postulated</span> to occur during inhibition of ribonucleotide reductases by 2?-azido-2?-deoxynucleotides</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Model 3?-azido-3?-deoxynucleosides with thiol or vicinal dithiol substituents at C2? or C5? were synthesized to study reactions <span class="hlt">postulated</span> to occur during inhibition of ribonucleotide reductases by 2?-azido-2?-deoxynucleotides. Esterification of 5?-(tert-butyldiphenylsilyl)-3?-azido-3?-deoxyadenosine and 3?-azido-3?-deoxythymidine (AZT) with 2,3-S-isopropylidene-2,3-dimercaptopropanoic acid or N-Boc-S-trityl-L-cysteine and deprotection gave 3?-azido-3?-deoxy-2?-O-(2,3-dimercaptopropanoyl or cysteinyl)adenosine and the 3?-azido-3?-deoxy-5?-O-(2,3-dimercaptopropanoyl or cysteinyl)thymidine analogs. Density functional calculations predicted that intramolecular reactions between generated thiyl radicals and an azido group on such model compounds would be exothermic by 33.6-41.2 kcal/mol and have low energy barriers of 10.4-13.5 kcal/mol. Reduction of the azido group occurred to give 3?-amino-3?-deoxythymidine, which was <span class="hlt">postulated</span> to occur with thiyl radicals generated by treatment of 3?-azido-3?-deoxy-5?-O-(2,3-dimercaptopropanoyl)thymidine with 2,2?-azobis-(2-methyl-2-propionamidine) dihydrochloride. Gamma radiolysis of N2O-saturated aqueous solutions of AZT and cysteine produced 3?-amino-3?-deoxythymidine and thymine most likely by both radical and ionic processes.</p> <div class="credits"> <p class="dwt_author">Dang, Thao P.; Sobczak, Adam J.; Mebel, Alexander M.; Chatgilialoglu, Chryssostomos; Wnuk, Stanislaw F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">189</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22549025"> <span id="translatedtitle">In vitro cultured Neoparamoeba perurans causes amoebic gill disease in Atlantic salmon and fulfils Koch's <span class="hlt">postulates</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Amoebic gill disease (AGD) in marine farmed Atlantic salmon is of growing concern worldwide and remains a significant health issue for salmon growers in Australia. Until now the aetiological agent, Neoparamoeba perurans, has not been amenable to in vitro culture and therefore Koch's <span class="hlt">postulates</span> could not be fulfilled. The inability to culture the amoeba has been a limiting factor in the progression of research into AGD and required the maintenance of an on-going laboratory-based infection to supply infective material. Culture methods using malt yeast agar with sea water overlaid and subculturing every 3-4 days have resulted in the establishment of a clonal culture of N. perurans, designated clone 4. Identity of the amoeba was confirmed by PCR. After 70 days in culture clone 4 infected Atlantic salmon, causing AGD, and was re-isolated from the infected fish. Diagnosis was confirmed by histology and the infectious agent identified by PCR and in situ hybridisation using oligonucleotide primers and probes previously developed and specific to N. perurans. This study has fulfilled Koch's <span class="hlt">postulates</span> for N. perurans as a causative agent of AGD and illustrates its free-living and parasitic nature. PMID:22549025</p> <div class="credits"> <p class="dwt_author">Crosbie, P B B; Bridle, A R; Cadoret, K; Nowak, B F</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">190</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JSeis..17..593M"> <span id="translatedtitle">Ground motion estimation in Delhi from <span class="hlt">postulated</span> regional and local earthquakes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Ground motions are estimated at 55 sites in Delhi, the capital of India from four <span class="hlt">postulated</span> earthquakes (three regional M w = 7.5, 8.0, and 8.5 and one local). The procedure consists of (1) synthesis of ground motion at a hard reference site (NDI) and (2) estimation of ground motion at other sites in the city via known transfer functions and application of the random vibration theory. This work provides a more extensive coverage than earlier studies (e.g., Singh et al., Bull Seism Soc Am 92:555-569, 2002; Bansal et al., J Seismol 13:89-105, 2009). The Indian code response spectra corresponding to Delhi (zone IV) are found to be conservative at hard soil sites for all <span class="hlt">postulated</span> earthquakes but found to be deficient for M w = 8.0 and 8.5 earthquakes at soft soil sites. Spectral acceleration maps at four different natural periods are strongly influenced by the shallow geological and soil conditions. Three pockets of high acceleration values are seen. These pockets seem to coincide with the contacts of (a) Aravalli quartzite and recent Yamuna alluvium (towards the East), (b) Aravalli quartzite and older quaternary alluvium (towards the South), and (c) older quaternary alluvium and recent Yamuna alluvium (towards the North).</p> <div class="credits"> <p class="dwt_author">Mittal, Himanshu; Kumar, Ashok; Kamal</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">191</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23453733"> <span id="translatedtitle">Koch's <span class="hlt">postulates</span> and the pathogenesis of comparative infectious disease causation associated with Bartonella species.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">In his homage to Lucretius ('Georgica'), Vergil is credited with stating: 'Felix qui potuit rerum cognoscere causas' ('Fortunate is he who knows the causes of things'). Based on numerous commentaries and publications it is obvious that clinicians, diagnosticians and biomedical research scientists continue to struggle with disease causation, particularly in the assessment of the pathogenic role of 'stealth pathogens' that produce persistent infections in the host. Bartonella species, because of their evolutionary ability to induce persistent intravascular infections, present substantial challenges for researchers attempting to clarify the ability of these stealth bacteria to cause disease. By studying the comparative biological and pathological behaviour of microbes across mammalian genera, researchers might be able more rapidly to advance medical science and, subsequently, patient care by undertaking focused research efforts involving a single mammalian species or by attempting to recapitulate a complex disease in an rodent model. Therefore, in an effort to further assist in the establishment of disease causation by stealth pathogens, we use recent research observations involving the genus Bartonella to propose an additional <span class="hlt">postulate</span> of comparative infectious disease causation to Koch's <span class="hlt">postulates</span>. PMID:23453733</p> <div class="credits"> <p class="dwt_author">Breitschwerdt, E B; Linder, K L; Day, M J; Maggi, R G; Chomel, B B; Kempf, V A J</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">192</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5051952"> <span id="translatedtitle">Analysis of radiation doses from operation of <span class="hlt">postulated</span> commercial spent fuel transportation systems: Main report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report contains a system study of estimated radiation doses to the public and workers resulting from the transport of spent fuel from commercial nuclear power reactors to a geologic repository. The report contains a detailed breakdown of activities and a description of time/distance/dose-rate estimates for each activity within the system. Collective doses are estimated for each of the major activities at the reactor site, in transit, and at the repository receiving facility. Annual individual doses to the maximally exposed individuals or groups of individuals are also estimated. A total of 17 alternatives and subalternatives to the <span class="hlt">postulated</span> reference transportation system are identified, conceptualized, and their dose-reduction potentials and costs estimated. Resulting ratios of ..delta..cost/..delta..collective system dose for each alternative relative to the <span class="hlt">postulated</span> reference transportation system are given. Most of the alternatives evaluated are estimated to provide both cost and dose reductions. Major reductions in transportation system dose and cost are estimated to result from using higher-capacity rail and truck casks, and particularly when replacing legalweight truck casks with ''advanced design'' overweight truck casks. The greatest annual dose reduction to the highest exposed individual workers (i.e., at the repository) is estimated to be achieved by using remote handling equipment for the cask handling operations at the repository. Additional shielding is also effective in reducing doses to both radiation workers at the reactor and repository and to transport workers. 69 refs., 36 figs., 156 tabs.</p> <div class="credits"> <p class="dwt_author">Schneider, K.J.; Hostick, C.J.; Ross, W.A.; Peterson, R.W.; Smith, R.I.; Stiles, D.L.; Daling, P.M.; Weakley, S.A.; Grinde, R.B.; Young, J.R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">193</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.T12D..01K"> <span id="translatedtitle"><span class="hlt">Melt</span> Segregation in Extrusion and Torsion Experiments on Partially Molten Rocks</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Shear deformation of partially molten rocks results in significant segregation of the low-viscosity <span class="hlt">melt</span> phase, producing both a broad background redistribution of <span class="hlt">melt</span> and a pronounced localization into <span class="hlt">melt</span>-enriched bands. Important in the process of <span class="hlt">melt</span> segregation is the strong dependence of viscosity on <span class="hlt">melt</span> fraction (Stevenson, 1989) combined with the anisotropic viscosity that results from a stress-induced anisotropic distribution of <span class="hlt">melt</span> at the grain scale (Takei and Holtzman, 2009). We have investigated both types of <span class="hlt">melt</span> segregation using narrow-channel extrusion experiments and high-strain torsion experiments. In aggregates of anorthite plus 8% <span class="hlt">melt</span> extruded several millimeters into a 2-mm diameter tube, <span class="hlt">melt</span> segregation leads to an increase to12% <span class="hlt">melt</span> at the sample-tube interface and to a decrease to 6% <span class="hlt">melt</span> at the tube center. In aggregates of olivine plus MORB deformed in torsion, <span class="hlt">melt</span> flows from the exterior toward the interior of the sample. For a sample with an average <span class="hlt">melt</span> content of 10% twisted to a shear strain of 10, the <span class="hlt">melt</span> content at the outer radius is ~7%, while the <span class="hlt">melt</span> content at the inner <span class="hlt">core</span> is ~13%. If a few percent chromite is added to samples of olivine plus MORB to decrease the permeability and thus the compaction length, <span class="hlt">melt</span> segregates into an anastomosing network of <span class="hlt">melt</span>-enriched bands that are oriented ~20o to the shear plane and antithetic to the shear direction. A similar <span class="hlt">melt</span>-enriched band structure dominates the microstructure of aggregates of anorthite plus several percent <span class="hlt">melt</span> deformed to high strain in torsion. Both the broad-background and the local segregation of <span class="hlt">melt</span> profoundly influence the viscosity and permeability structure not only of laboratory samples but also of partially molten regions of Earth's interior.</p> <div class="credits"> <p class="dwt_author">Kohlstedt, D. L.; Qi, C.; Zimmerman, M. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">194</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48939010"> <span id="translatedtitle">Sulfur's impact on <span class="hlt">core</span> evolution and magnetic field generation on Ganymede</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Analysis of the <span class="hlt">melting</span> relationships of potential <span class="hlt">core</span> forming materials in Ganymede indicate that fluid motions, a requirement for a dynamo origin for the satellite's magnetic field, may be driven, in part, either by iron (Fe) “snow” forming below the <span class="hlt">core</span>-mantle boundary or solid iron sulfide (FeS) floating upward from the deep <span class="hlt">core</span>. Eutectic <span class="hlt">melting</span> temperatures and eutectic sulfur contents</p> <div class="credits"> <p class="dwt_author">Steven A. Hauck; Jonathan M. Aurnou; Andrew J. Dombard</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">195</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFM.V31D0685S"> <span id="translatedtitle">Iron Diffusivity in Water Saturated Rhyolite <span class="hlt">Melt</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have quantified experimentally the bulk chemical diffusivity of iron and the solubility of magnetite in peraluminous, water-saturated rhyolite <span class="hlt">melt</span> at 100 MPa and 800°C by performing experiments in which we equilibrated a single crystal of magnetite with water-saturated rhyolite <span class="hlt">melt</span>. The oxygen fugacity of each run was buffered at nickel-nickel oxide (NNO) and the assemblage was saturated with a 1.8 wt. % NaCl eq. NaCl-KCl- FeCl2-HCl-H2O volatile phase. The experimental charge contained a cylinder of magnetite (activity Fe3O4=1), <span class="hlt">cored</span> from a single crystal of magnetite and placed at the base of a gold capsule, synthetic rhyolite glass placed above the magnetite cylinder and aqueous vapor which occupied the remaining capsule volume. The concentration profiles of FeO (and Na2O, K2O, Al2O3, SiO2 and Cl) in the quenched <span class="hlt">melt</span> (i.e., glass) were measured over a distance of 400 microns beginning at the magnetite-rhyolite interface and moving orthogonally away from this interface into the glass until the concentration of iron fell below the limit of detection. Diffusion profiles were fit by inverting the measured concentrations of iron in the <span class="hlt">melt</span> through the error function and solving for the diffusion coefficient assuming a stationary planar boundary; the near-intersection of the error function regression with the origin justifies this assumption. The calculated bulk chemical diffusivity for iron in H2O- saturated rhyolite is 4 E-10 cm2 sec-1; this measured diffusivity is consistent, albeit one-half to one order of magnitude lower than data for other divalent elements (Ca, Mg, Sn) in rhyolite. The Co value used to fit the diffusion profiles is consistent with published data for the equilibrium concentration of iron in rhyolite <span class="hlt">melt</span> and, thus, the data yield the solubility of iron in water-saturated rhyolite <span class="hlt">melt</span>. The aluminum saturation index (ASI) of the <span class="hlt">melt</span>, hence concentrations of Na2O, K2O and Al2O3, remains essentially constant in the <span class="hlt">melt</span> across the entire measured diffusion length indicating that the bulk diffusivity of iron is not affected by coupled diffusion with these major elements. The chlorine concentration in the <span class="hlt">melt</span>, however, increases markedly toward the magnetite-glass interface. This finding suggests that iron and chlorine are associated strongly in the <span class="hlt">melt</span> and that the presence of iron in the <span class="hlt">melt</span>, owing to magnetite dissolution increases significantly the chlorine "solubility" in the <span class="hlt">melt</span>. The new results constrain the growth and dissolution rates of iron-bearing minerals during the evolution of hydrous felsic <span class="hlt">melt</span>, including magma mixing, and the apparent association of iron and chlorine in the <span class="hlt">melt</span> provides important constraints on the mass transfer of iron, chlorine and other metals, to an exsolved volatile phase and how this impacts the acidity, hence metal-scavenging potential, of the volatile phase.</p> <div class="credits"> <p class="dwt_author">Simon, A. C.; Bell, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">196</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/876117"> <span id="translatedtitle">'Mapping' of <span class="hlt">postulated</span> Ir genes within HLA by studies in allergic populations.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Analysis of specific IgE responses to highly purified allergens provides a particularly good model to study the genetics of human immune response. The use of this model is illustrated by studies of large populations of allergic individuals in terms of their HLA phenotype, basal total IgE level and specific IgE-mediated sensitivities to rye grass group I (Rye I) and to ragweed Ra3. We find significant associations between HLA-B8 and Rye I response and HLA-A2 and Ra3 response, which become more striking in those atypical allergic subjects who have low total IgE levels. Our studies point to the importance of genetic regulation of basal IgE level in determining specific IgE response. Also, they suggest possible approaches toward a tentative 'mapping' of <span class="hlt">postulated</span> Ir genes based on the linkage disequilibrium existing within the HLA complex. PMID:876117</p> <div class="credits"> <p class="dwt_author">Marsh, D G; Chase, G A; Goodfriend, L; Bias, W B</p> <p class="dwt_publisher"></p> <p class="publishDate">1977-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">197</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3799387"> <span id="translatedtitle">Existence of an information unit as a <span class="hlt">postulate</span> of quantum theory</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Does information play a significant role in the foundations of physics? Information is the abstraction that allows us to refer to the states of systems when we choose to ignore the systems themselves. This is only possible in very particular frameworks, like in classical or quantum theory, or more generally, whenever there exists an information unit such that the state of any system can be reversibly encoded in a sufficient number of such units. In this work, we show how the abstract formalism of quantum theory can be deduced solely from the existence of an information unit with suitable properties, together with two further natural assumptions: the continuity and reversibility of dynamics, and the possibility of characterizing the state of a composite system by local measurements. This constitutes a set of <span class="hlt">postulates</span> for quantum theory with a simple and direct physical meaning, like the ones of special relativity or thermodynamics, and it articulates a strong connection between physics and information.</p> <div class="credits"> <p class="dwt_author">Masanes, Lluis; Muller, Markus P.; Augusiak, Remigiusz; Perez-Garcia, David</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">198</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1980Natur.284..431W"> <span id="translatedtitle">Radiogenic <span class="hlt">melting</span> of primordial comet interiors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">melting</span> of the <span class="hlt">core</span> of a primordial comet due to heat released upon the radioactive decay of Al-26 contained within it is discussed. For a spherical, 10-km comet composed of loose snow and mineral grains in the primordial nebula, it is shown that a large fluid dust, droplet and vapor <span class="hlt">core</span> could develop surrounded by a 1-km thick icy shell with enhanced conductivity and a further 2 km of snow metamorphosing by sublimation, diffusion and condensation into larger ice crystals. As the radioactivity decays, the comet center would gradually refreeze by the deposition of frost and hail on the interior of the ice shell, resulting in a hollow <span class="hlt">core</span> which could explain the presumed splitting of some disintegrating comets and could have provided a well-protected environment for elementary biological systems.</p> <div class="credits"> <p class="dwt_author">Wallis, M. K.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">199</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=HEDLSA981"> <span id="translatedtitle"><span class="hlt">Postulated</span> Accident Conditions for Air Cleaning Systems and Radiological Dose Assessments for Containment Options.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Ambient conditions and performance requirements for emergency air cleaning systems applicable to commercial LMFBR plants were studied. The focus of this study centered on aerosol removal under hypothetical <span class="hlt">core</span> disruptive accident conditions. Effort compl...</p> <div class="credits"> <p class="dwt_author">R. K. Hilliard A. K. Postma</p> <p class="dwt_publisher"></p> <p class="publishDate">1975-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">200</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE82019448"> <span id="translatedtitle">Formation and Characterization of Fission-Product Aerosols under <span class="hlt">Postulated</span> HTGR Accident Conditions.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The paper presents the results of an experimental investigation on the formation mechanism and physical characterization of simulated nuclear aerosols that could likely be released during an HTGR <span class="hlt">core</span> heat-up accident. Experiments were carried out in a hi...</p> <div class="credits"> <p class="dwt_author">I. N. Tang H. R. Munkelwitz</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_9");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">201</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61307886"> <span id="translatedtitle">Experimental study of the fragmentation and quench behavior of corium <span class="hlt">melts</span> in water</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The interaction of molten <span class="hlt">core</span> materials with water has been investigated for the pour stream mixing mode. This interaction plays a crucial role during the later stages of in-vessel <span class="hlt">core</span> <span class="hlt">melt</span> progression inside a light water reactor such as during the TMI-2 accident. The key issues which arise during the molten <span class="hlt">core</span> relocation include: (1) the thermal attack and possible</p> <div class="credits"> <p class="dwt_author">S. K. Wang; C. A. Blomquist; B. W. Spencer; L. M. McUmber; J. P. Schneider; IL Urbana</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">202</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pbslearningmedia.org/resource/ipy07.sci.ess.watcyc.lpmeltingice/"> <span id="translatedtitle"><span class="hlt">Melting</span> Sea Ice</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This activity uses a mix of multimedia resources and hands-on activities to support a storyline of investigation into <span class="hlt">melting</span> sea ice. The lesson begins with a group viewing of a video designed to get students to consider both the local and global effects of climate change. The class then divides into small groups for inquiry activities on related topics followed by a presentation of the findings to the entire class. A final class discussion reveals a more complex understanding of both the local and global impacts of <span class="hlt">melting</span> sea ice.</p> <div class="credits"> <p class="dwt_author">Domain, Wgbh E.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">203</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20060024602&hterms=viscosity&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dviscosity"> <span id="translatedtitle">Viscosity Measurement for Tellurium <span class="hlt">Melt</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The viscosity of high temperature Te <span class="hlt">melt</span> was measured using a new technique in which a rotating magnetic field was applied to the <span class="hlt">melt</span> sealed in a suspended ampoule, and the torque exerted by rotating <span class="hlt">melt</span> flow on the ampoule wall was measured. Governing equations for the coupled <span class="hlt">melt</span> flow and ampoule torsional oscillation were solved, and the viscosity was extracted from the experimental data by numerical fitting. The computational result showed good agreement with experimental data. The <span class="hlt">melt</span> velocity transient initiated by the rotating magnetic field reached a stable condition quickly, allowing the viscosity and electrical conductivity of the <span class="hlt">melt</span> to be determined in a short period.</p> <div class="credits"> <p class="dwt_author">Lin, Bochuan; Li, Chao; Ban, Heng; Scripa, Rosalia N.; Su, Ching-Hua; Lehoczky, Sandor L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">204</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013GeCoA.114...52A"> <span id="translatedtitle">Solubility of CH4 in a synthetic basaltic <span class="hlt">melt</span>, with applications to atmosphere-magma ocean-<span class="hlt">core</span> partitioning of volatiles and to the evolution of the Martian atmosphere</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We employ a double capsule technique to determine the solubility of CH4 in haplobasaltic (Fe-free) liquid under conditions of constrained methane fugacity, f, at pressures of 0.7-3 GPa at 1400-1450 °C. Dissolved C-O-H species are examined with FTIR and Raman spectroscopy, and CH4 and CH3- are the only C-bearing species detected. Carbon solubilities are quantified using SIMS, range from 70 to 480 ppm when calculated as CH4, and increase with pressure. Concentrations are parameterized with a thermodynamic model and are found to be related to f and pressure. Application of this thermodynamic model shows dissolved CH4 contents of graphite-saturated magmas are little-influenced by pressure for conditions of fixed f relative to metal-oxide buffers and fixed total H content. Because f of graphite-saturated systems increases with the square of hydrogen fugacity, dissolved f increases with decreasing f and increases exponentially with increasing total H content. The experimentally-observed increase with pressure is related to variations in f and H content. Dissolved CH4 contents of Martian magmas in their source regions are small, such that it is unlikely that magmatic CH4 is a principal contributor to greenhouse conditions early in Martian history. Concentrations of dissolved C-O-H volatiles in a magma ocean early in the history of a terrestrial planet may be diminished by reducing conditions, leading to development of a massive atmosphere and a greatly decreased inventory of volatiles stored in planetary interiors at the outset of planetary history. Dissolution of methane may enhance the retention of C in the silicate Earth during <span class="hlt">core</span> formation, but experimental evaluation of its influence on metal/silicate partitioning of C requires careful matching of the magmatic H concentration between experiments and natural systems.</p> <div class="credits"> <p class="dwt_author">Ardia, P.; Hirschmann, M. M.; Withers, A. C.; Stanley, B. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">205</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010PhRvB..81u4109J"> <span id="translatedtitle">Shock <span class="hlt">melting</span> of cerium</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Shock-wave experiments were performed to examine the <span class="hlt">melt</span> transition for cerium. Despite past work which points to a higher-pressure transition, the large volume collapse associated with the low-pressure ?-? phase transition is expected to result in a low-pressure <span class="hlt">melt</span> transition. Multiple experimental configurations including front-surface impact and transmission experiments using velocimetry were used to obtain Hugoniot data and sound-speed data for impact stresses up to approximately 18 GPa. Sound-speed data exhibit a structured release consisting of a longitudinal wave followed by a slower plastic wave. The difference between these two wave speeds is observed to decrease with increasing impact stress until a single shock wave is observed indicating the onset of the <span class="hlt">melt</span> transition which was estimated to be 10.24±0.34GPa . Additional data show that the sound speed is in agreement with liquid data at approximately 18 GPa likely indicating the completion of the <span class="hlt">melt</span> transition. Further results and implications are discussed.</p> <div class="credits"> <p class="dwt_author">Jensen, B. J.; Cherne, F. J.; Cooley, J. C.; Zhernokletov, M. V.; Kovalev, A. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">206</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.nbclearn.com/climate/cuecard/52577"> <span id="translatedtitle"><span class="hlt">Melting</span> Mountain Glaciers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">The world's glaciers are shrinking at alarming rates, and many scientists believe it is due to changes in climate. Dr. Lonnie Thompson of Ohio State University and Dr. Douglas Hardy of UMass-Amherst discuss glaciers and how they <span class="hlt">melt</span>, and pay special attention to Africa's tallest mountain, Mt. Kilimanjaro. "Changing Planet" is produced in partnership with the National Science Foundation.</p> <div class="credits"> <p class="dwt_author">Learn, Nbc</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-10-07</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">207</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.bookrags.com/research/freezing-and-melting-woes-01/"> <span id="translatedtitle">Freezing and <span class="hlt">Melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This article tells how the freezing point of a substance is also its <span class="hlt">melting</span> point. The energy of the substance's molecules changes with temperature, thus with changes in state. Also described is how freezing points can be lowered, or depressed, by adding a substance.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">208</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6434146"> <span id="translatedtitle">SAS4A: A computer model for the analysis of hypothetical <span class="hlt">core</span> disruptive accidents in liquid metal reactors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">To ensure that the public health and safety are protected under any accident conditions in a Liquid Metal Fast Breeder Reactor (LMFBR), many accidents are analyzed for their potential consequences. The SAS4A code system, described in this paper, provides such an analysis capability, including the ability to analyze low probability events such as the Hypothetical <span class="hlt">Core</span> Disruptive Accidents (HCDAs). The SAS4A code system has been designed to simulate all the events that occur in a LMFBR <span class="hlt">core</span> during the initiating phase of a Hypothetical <span class="hlt">Core</span> Disruptive Accident. During such <span class="hlt">postulated</span> accident scenarios as the Loss-of-Flow and Transient Overpower events, a large number of interrelated physical phenomena occur during a relatively short time. These phenomena include transient heat transfer and hydrodynamic events, coolant boiling and fuel and cladding <span class="hlt">melting</span> and relocation. During to the strong neutronic feedback present in a nuclear reactor, these events can significantly influence the reactor power. The SAS4A code system is used in the safety analysis of nuclear reactors, in order to estimate the energetic potential of very low probability accidents. The results of SAS4A simulations are also used by reactor designers in order to build safer reactors and eliminate the possibility of any accident which could endanger the public safety.</p> <div class="credits"> <p class="dwt_author">Tentner, A.M.; Birgersson, G.; Cahalan, J.E.; Dunn, F.E.; Kalimullah; Miles, K.J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">209</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6643264"> <span id="translatedtitle">Speciation in granitic <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Refinement of the cryoscopic equations for the major granitic <span class="hlt">melt</span> components, NaAlSi/sub 3/O/sub 8/(ab), CaAl/sub 2/O/sub 8/(an), KAlSi/sub 3/O/sub 8/(or), and Si/sub 4/O/sub 8/(qz), has led to the recognition of several major speciation reactions in anhydrous and hydrous <span class="hlt">melts</span> of the system Ab-An-Or-Qz-H/sub 2/O. These reactions involve either dissociation of the feldspar-like components, as in incongruent <span class="hlt">melting</span>, or interaction between them and qz. In all cases of interaction, one of the speciation products has the stoichiometry of dpy or py (pyrophyllite) (Al/sub 1.455/Si/sub 2.91/O/sub 8/ +/- 0.73H/sub 2/O), in which Al is presumed to be in either fivefold (dpy) or sixfold (py) coordination. The py component also is a major product of speciation by interaction between sil (Al/sub 3.2/Si/sub 1.6/O/sub 8/) and qz in peraluminous <span class="hlt">melts</span> of the system Ab-Or-Qz-Sil-H/sub 2/O; as a consequence, the quartz liquidus field boundary is shifted to lower temperatures and toward qz. There is no evidence in peraluminous haplogranite <span class="hlt">melts</span> for the existence of a muscovite-like species. Application of the refined thermodynamic model to the system Ab-Qz-Eu - H/sub 2/O at 2.0 kbar predicts the occurrence of a eu and qz-consuming reaction that produces a petalite-like species and a consequent dramatic shift in liquidus field boundaries. Higher pressures favor conversion of pe to qz + sp. In the spodumene-like species, sp, Al presumably is six-coordinated.</p> <div class="credits"> <p class="dwt_author">Burnham, C.W.; Nekvasil, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">210</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26600470"> <span id="translatedtitle">The COMET-L3 experiment on long-term <span class="hlt">melt</span>–concrete interaction and cooling by surface flooding</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The COMET-L3 experiment considers the long-term situation of corium\\/concrete interaction in an anticipated <span class="hlt">core</span> <span class="hlt">melt</span> accident of a light water reactor after the metal <span class="hlt">melt</span> is layered beneath the oxide <span class="hlt">melt</span>. The experimental focus is on the cavity formation in the basemat and the risk of a long-term basemat penetration by the metallic part of the <span class="hlt">melt</span>. The experiment investigates</p> <div class="credits"> <p class="dwt_author">Alexei Miassoedov; Hans Alsmeyer; Thomas Cron; Jerzy Foit</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">211</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.bankofcanada.ca/en/res/tr/2001/tr89.pdf"> <span id="translatedtitle"><span class="hlt">Core</span> Inflation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Bank of Canada uses <span class="hlt">core</span> CPI inflation, the year-over-year rate of change of the consumer price index excluding food, energy, and the effects of changes in indirect taxes, as the operational guide for monetary policy. In this report we study the concept and measurement of <span class="hlt">core</span> or underlying inflation more generally by examining several alternative measures of <span class="hlt">core</span> inflation,</p> <div class="credits"> <p class="dwt_author">Seamus Hogan; Marianne Johnson; Thérèse Laflèche</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">212</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26597106"> <span id="translatedtitle">Concept of a <span class="hlt">core</span> cooling system and experiments performed</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">One of the problems which must be solved in severe accidents is the <span class="hlt">melt</span>-concrete interaction which does occur when the <span class="hlt">core</span> debris penetrates the lower pressure vessel head and contacts the basement. To prevent these accident consequences, a <span class="hlt">core</span> catcher concept is proposed to be integrated into a new pressurized-water reactor design. The <span class="hlt">core</span> catcher achieves coolability by spreading and</p> <div class="credits"> <p class="dwt_author">H. Alsmeyer; W. Tromm</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">213</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2174837"> <span id="translatedtitle">Analysis of a Schnute <span class="hlt">postulate</span>-based unified growth mode for model selection in evolutionary computations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">In order to evaluate the feasibility of a combined evolutionary algorithm-information theoretic approach to select the best model from a set of candidate invasive species models in ecology, and/or to evolve the most parsimonious model from a suite of competing models by comparing their relative performance, it is prudent to use a unified model that covers a myriad of situations. Using Schnute’s <span class="hlt">postulates</span> as a starting point, we present a single, unified model for growth that can be successfully utilized for model selection in evolutionary computations. Depending on the parameter settings, the unified equation can describe several growth mechanisms. Such a generalized model mechanism, which encompasses a suite of competing models, can be successfully implemented in evolutionary computational algorithms to evolve the most parsimonious model that best fits ground truth data. We have done exactly this by testing the effectiveness of our reaction-diffusion-advection (RDA) model in an evolutionary computation model selection algorithm. The algorithm was validated (with success) against field data sets of the Zebra mussel invasion of Lake Champlain in the United States.</p> <div class="credits"> <p class="dwt_author">Bentil, D.E.; Osei, B.M.; Ellingwood, C.D.; Hoffmann, J.P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">214</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17197072"> <span id="translatedtitle">Analysis of a Schnute <span class="hlt">postulate</span>-based unified growth model for model selection in evolutionary computations.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">In order to evaluate the feasibility of a combined evolutionary algorithm-information theoretic approach to select the best model from a set of candidate invasive species models in ecology, and/or to evolve the most parsimonious model from a suite of competing models by comparing their relative performance, it is prudent to use a unified model that covers a myriad of situations. Using Schnute's <span class="hlt">postulates</span> as a starting point [Schnute, J., 1981. A versatile growth model with statistically stable parameters, Can. J. Fish Aquat. Sci. 38, 1128-1140], we present a single, unified model for growth that can be successfully utilized for model selection in evolutionary computations. Depending on the parameter settings, the unified equation can describe several growth mechanisms. Such a generalized model mechanism, which encompasses a suite of competing models, can be successfully implemented in evolutionary computational algorithms to evolve the most parsimonious model that best fits ground truth data. We have done exactly this by testing the effectiveness of our reaction-diffusion-advection (RDA) model in an evolutionary computation model selection algorithm. The algorithm was validated (with success) against field data sets of the Zebra mussel invasion of Lake Champlain in the United States. PMID:17197072</p> <div class="credits"> <p class="dwt_author">Bentil, D E; Osei, B M; Ellingwood, C D; Hoffmann, J P</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">215</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4041178"> <span id="translatedtitle">Serum-derived bovine immunoglobulin/protein isolate: <span class="hlt">postulated</span> mechanism of action for management of enteropathy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The health and performance of the gastrointestinal tract is influenced by the interaction of a variety of factors, including diet, nutritional status, genetics, environment, stress, the intestinal microbiota, immune status, and gut barrier. Disruptions in one or more of these factors can lead to enteropathy or intestinal disorders that are known to occur in concert with certain disease states or conditions such as irritable bowel syndrome or human immunodeficiency virus (HIV) infection. Nutritional support in the form of a medical food along with current therapies could help manage the adverse effects of enteropathy, which include effects on nutrient digestion, absorption, and metabolism, as well as utilization of nutrients from foodstuffs. Numerous studies have demonstrated that oral administration of plasma- or serum-derived protein concentrates containing high levels of immunoglobulins can improve weight management, normalize gut barrier function, and reduce the severity of enteropathy in animals. Recent trials in humans provide preliminary evidence that a serum-derived bovine immunoglobulin/protein isolate is safe and improves symptoms, nutritional status, and various biomarkers associated with enteropathy in patients with HIV infection or diarrhea-predominant irritable bowel syndrome. This review summarizes data from preclinical and clinical studies with immunoglobulin-containing plasma/serum protein concentrates, with a focus on the <span class="hlt">postulated</span> mode of action of serum-derived bovine immunoglobulin/protein isolate for patients with enteropathy.</p> <div class="credits"> <p class="dwt_author">Petschow, Bryon W; Burnett, Bruce; Shaw, Audrey L; Weaver, Eric M; Klein, Gerald L</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">216</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1334736"> <span id="translatedtitle">General continuum analysis of transport through pores. I. Proof of Onsager's reciprocity <span class="hlt">postulate</span> for uniform pore.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The nonelectrolyte (Js) and volume (Jv) flux across a membrane is usually described in terms of two equations derived from the theory of irreversible thermodynamics: (see article) where delta c and delta P are the concentration and pressure difference; omega and Lp are the diffuse and hydraulic permeability; and sigma s and sigma v are the reflection coefficients. If Onsager's reciprocity <span class="hlt">postulate</span> is assumed, it can be shown that signa s and sigma v are equal. This is an important assumption because it allows one to apply the continuum theory relationship between sigma s and the pore radius to experimental measurements of sigma v. In this paper, general continuum expressions for both the Jv (a new result) and Js equation will be derived and the equality of sigma s and sigma v proved. The proof uses only general hydrodynamic results and does not require explicit solutions for the drag coefficients or, for example, the assumption that the solute is in the center of the pore. The proof applys to arbitrarily shaped solutes and any pore whose shape is independent of axial position (uniform). In addition, new expressions for the functional dependence of omega and sigma on the pore radius are derived (including the effect of the particle lying off the pore axis). These expressions differ slightly from earlier results and are probably more accurate.</p> <div class="credits"> <p class="dwt_author">Levitt, D G</p> <p class="dwt_publisher"></p> <p class="publishDate">1975-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">217</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=Thermodynamics&pg=6&id=EJ838181"> <span id="translatedtitle">Thermodynamics of Oligonucleotide Duplex <span class="hlt">Melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary"><span class="hlt">Melting</span> temperatures of oligonucleotides are useful for a number of molecular biology applications, such as the polymerase chain reaction (PCR). Although <span class="hlt">melting</span> temperatures are often calculated with simplistic empirical equations, application of thermodynamics provides more accurate <span class="hlt">melting</span> temperatures and an opportunity for students to apply…</p> <div class="credits"> <p class="dwt_author">Schreiber-Gosche, Sherrie; Edwards, Robert A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">218</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE20111014857"> <span id="translatedtitle">OECD MCCI Project. <span class="hlt">Melt</span> Eruption Test (MET) Design Report. Revision 2.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The <span class="hlt">Melt</span> Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten <span class="hlt">core</span>-concrete interaction when the reactants are flooded from above. These tests...</p> <div class="credits"> <p class="dwt_author">D. J. Kilsdonk M. T. Farmer R. W. Aeschlimann S. Basu S. Lomperski</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">219</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21072784"> <span id="translatedtitle">Simeco Tests in a <span class="hlt">Melt</span> Stratified Pool</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">In the last phase of the <span class="hlt">core</span> degradation, an oxidic <span class="hlt">melt</span> pool of mainly UO{sub 2}; ZrO{sub 2}, and unoxidized Zircaloy and stain-less steel will form in the lower head of the RPV (Theofanous et al., 1996). A molten metal layer (composed mainly of Fe and Zr) will rest on the top of the crust of the oxidic pool. A thin oxidic crust layer of frozen <span class="hlt">core</span> material is formed on the vessel's inside wall. In this bounding configuration, thermal loads to the RPV walls are determined by natural convection heat transfer driven by internal heat sources. Decay heat from fission products is assumed to be generated uniformly within the oxidic pool and generally no heat generation is considered in the upper metallic layer. For example, in a hypothetical severe accident scenario for an AP600-like reactor, the following values can be expected: volumetric heat generation Q{sub v} {approx} 1 MW/m{sup 3}, volume of the oxidic pool V {approx} 10 m{sup 3}, radius R = 2 m, temperatures in the oxidic pool T {approx} 2700 deg. C, temperatures in the metal layer T {approx} 2000 deg. C, maximum depth ratio of the metal layer to the oxidic pool L{sub 12} {approx} 0:3, properties of the oxidic pool, depending on <span class="hlt">melt</span> composition, as characterized by the Prandtl number, Pr {approx} 0:6, properties of the metallic layer Pr < 0:1, the intensity of convective motion, as characterized by the Rayleigh number, Ra {approx} 10{sup 15} - 10{sup 16} (Theofanous et al., 1996). The time scale of <span class="hlt">core</span> <span class="hlt">melt</span> pool formation is estimated as 1/2 to 1 hour (Sehgal, 1999). Indeed, these estimates could vary, depending very much on the accident scenario and the type of reactor. (authors)</p> <div class="credits"> <p class="dwt_author">Gubaidullin, A.A.; Sehgal, B.R. [Royal Institute of Technology (KTH), Drottning Kristinas vaeg 33 A, 100 44, Stockholm (Sweden)</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">220</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMMR13A..02F"> <span id="translatedtitle">An integral approach to investigate planetary <span class="hlt">cores</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The same <span class="hlt">core</span>-mantle differentiation process was in operation during the early formation of the terrestrial planets, but it led to unique <span class="hlt">cores</span> for the Earth, Venus, Mars, and Mercury, with different magnetic fields, reflecting their different dynamic, physical, and chemical states. Assuming all terrestrial planets shared the same materials of the building block, the differences must be resulted from the different conditions of the early accretion and the subsequent planetary evolution unique to each planet. The pressures at the <span class="hlt">core</span>-mantle boundary of the terrestrial planets range from as low as 7 GPa to 136 GPa. The physical state (liquid or solid) for each planetary <span class="hlt">core</span> is closely tied to the <span class="hlt">melting</span> and chemical composition of the <span class="hlt">cores</span>. In order to determine the minimal temperature of a liquid <span class="hlt">core</span> or the maximal temperature of a solid <span class="hlt">core</span>, we have systematically investigated <span class="hlt">melting</span> relations in the binary systems Fe-FeS, Fe-C, and Fe-FeSi, move toward unravelling the crystallization sequence and element partitioning between solid and liquid metal in the ternary and quaternary systems up to 25 GPa, using multi-anvil apparatus. We have developed new techniques to analyze the quenched samples recovered from laser-heating diamond-anvil cell experiments using combination of focus ion beam (FIB) milling, high-resolution SEM imaging, and quantitative chemical analysis with silicon drift detector EDS. With precision milling of the laser-heating spot, we determined <span class="hlt">melting</span> using quenching texture criteria imaged with high-resolution SEM and the sulfur partitioning between solid and liquid at submicron spatial resolution. We have also re-constructed 3D image of the laser-heating spot at multi-megabar pressures to better constrain <span class="hlt">melting</span> point and understanding <span class="hlt">melting</span> process. The new techniques allow us to extend precise measurements of <span class="hlt">melting</span> relations to <span class="hlt">core</span> pressures in the laser-heating diamond-anvil cell. In addition to the static experiments, we also used shockwave compression to determine density, sound velocity, and <span class="hlt">melting</span> of <span class="hlt">core</span> materials up to liquid outer <span class="hlt">core</span> conditions. The integration of the static and dynamic compression data provides an extensive dataset over a wide pressure and temperature range that is necessary for establishing a comprehensive model of the planetary <span class="hlt">cores</span>, providing the best fit to the geophysical, cosmochemial, and geochemical observations.</p> <div class="credits"> <p class="dwt_author">Fei, Y.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_10");' href="#" title="Previous Page"> <img 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href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_13");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">221</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60687820"> <span id="translatedtitle">OECD MCCI project <span class="hlt">Melt</span> Eruption Test (MET) design report, Rev. 2. April 15, 2003</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The <span class="hlt">Melt</span> Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten <span class="hlt">core</span>-concrete interaction when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the <span class="hlt">melt</span> to the overlying water pool,</p> <div class="credits"> <p class="dwt_author">M. T. Farmer; S. Lomperski; D. J. Kilsdonk; R. W. Aeschlimann; S. Basu</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">222</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/24265921"> <span id="translatedtitle">Analysis of Partial <span class="hlt">Melting</span> in Metal Powder Bed with Constant Heat Flux</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Rapid <span class="hlt">melting</span> of a subcooled single-component metal powder bed in Selective Laser Sintering (SLS) is analyzed in this paper. Under irradiation of a pulse laser beam, the surface of the powder particle is molten first while the <span class="hlt">core</span> of the particle remains solid. The temperature of the liquid layer is higher than the <span class="hlt">melting</span> point, while the temperature of the</p> <div class="credits"> <p class="dwt_author">Bin Xiao; Yuwen Zhang</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">223</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014E%26PSL.390..199C"> <span id="translatedtitle">Experimental constraints on Mercury's <span class="hlt">core</span> composition</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The recent discovery of high S concentrations on the surface of Mercury by spacecraft measurements from the MESSENGER mission provides the potential to place new constraints on the composition of Mercury's large metallic <span class="hlt">core</span>. In this work, we conducted a set of systematic equilibrium metal-silicate experiments that determined the effect of different metallic compositions in the Fe-S-Si system on the S concentration in the coexisting silicate <span class="hlt">melt</span>. We find that metallic <span class="hlt">melts</span> with a range of S and Si combinations can be in equilibrium with silicate <span class="hlt">melts</span> with S contents consistent with Mercury's surface, but that such silicate <span class="hlt">melts</span> contain Fe contents lower than measured for Mercury's surface. If Mercury's surface S abundance is representative of the planet's bulk silicate composition and if the planet experienced metal-silicate equilibrium during planetary <span class="hlt">core</span> formation, then these results place boundaries on the range of possible combinations of Si and S that could be present as the light elements in Mercury's <span class="hlt">core</span> and suggest that Mercury's <span class="hlt">core</span> likely contains Si. Except for <span class="hlt">core</span> compositions with extreme abundances of Si, bulk Mercury compositions calculated by using the newly determined range of potential S and Si <span class="hlt">core</span> compositions do not resemble primitive meteorite compositions.</p> <div class="credits"> <p class="dwt_author">Chabot, Nancy L.; Wollack, E. Alex; Klima, Rachel L.; Minitti, Michelle E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">224</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://seagrant.uaf.edu/news/04ASJ/05.14.04permafrost.html"> <span id="translatedtitle"><span class="hlt">Melting</span> Beneath Our Feet</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This radio broadcast discusses how permafrost (permanently frozen ground) in Alaska and the Arctic has been <span class="hlt">melting</span>, and what the potential consequences might be. These include damage to many engineering structures and coastlines and the release of gases into the atmosphere which may compound the problem of climate warming. About two-thirds of Alaska is covered by permafrost and a recent report says a higher priority should be given to studying it. The clip is about 4 minutes in length.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">225</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://audio.scienceupdate.com/060815_sciup_melt.mp3"> <span id="translatedtitle"><span class="hlt">Melting</span> Ice Caps</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">From the remote village of Gambell, Alaska, listener Bob Woolf can see the polar ice <span class="hlt">melting</span>, and emailed us to ask if global warming would ever become irreversible. According to senior scientist Warren Washington of the National Center for Atmospheric Research, it probably already is, at least for the short term. That's because the greenhouse gases that are in the atmosphere now can last for decades or even centuries.</p> <div class="credits"> <p class="dwt_author">Science Update (AAAS;)</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-08-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">226</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5519488"> <span id="translatedtitle">Dynamics of surface <span class="hlt">melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The objective of this program is to study the phenomenon of surface disordering surface <span class="hlt">melting</span>'' of single crystals of metals at temperatures below that of bulk <span class="hlt">melting</span>. We use conventional static electron diffraction techniques as well as dynamic ultrafast reflection high-energy electron diffraction (RHEED) to study the temperature dependent surface structural behavior. Static RHEED experiments on surface disordering of Pb(110) crystal were conclusive on the existence of surface disordering at temperatures {approximately}50 K below the bulk <span class="hlt">melting</span> temperature. A large set of time-resolved RHEED experiments was conducted to study the thermal response of Pb(110) to {approximately}150-ps pulsed laser heating. The surface Debye-Waller effect was used to time resolve the evolution of surface temperature. This provided a picosecond time-resolved surface lattice structure and temperature probe. Results for laser fluences below the surface disordering temperature show agreement with a heat diffusion model. For laser fluences above the surface disordering temperature, surface disorder upon heating and regrowth of crystalline order were observed to be completely reversible within {approximately}150 ps. An extensive study of the temperature dependent surface disordering of Pb(100) using angle-resolved photoemission was conducted. Results show that the onset of surface disorder occurs at 586{plus minus}5 K. The number of disordered layers grow logarithmically to {approximately}4--5 monolayers at 599 K. Slight anisotropy, which favors disordering along the (011) azimuth compared to that along the (001) azimuth, was observed. 22 refs., 6 figs.</p> <div class="credits"> <p class="dwt_author">Elsayed-Ali, H.E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">227</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DP1485"> <span id="translatedtitle">Exothermic Reactions Leading to Unexpected Meltdown of Scrap Uranium--Aluminum Cermet <span class="hlt">Cores</span> During Outgassing.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">During routine outgassing of scrap uranium-aluminum cermet <span class="hlt">cores</span>, unexpected exothermic reactions released sufficient energy to <span class="hlt">melt</span> nine <span class="hlt">cores</span>. In the subsequent investigation, compounds in the scrap uranium were identified, the history of the material w...</p> <div class="credits"> <p class="dwt_author">L. W. Gray W. J. Kerrigan</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">228</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19940014950&hterms=Vitek&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DVitek%2B2"> <span id="translatedtitle"><span class="hlt">Melt</span> spinning study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Containerless processing of materials provides an excellent opportunity to study nucleation phenomena and produce unique materials, primarily through the formation of metastable phases and deep undercoolings. Deep undercoolings can be readily achieved in falling drops of molten material. Extended solute solubilities and greatly refined microstructures can also be obtained in containerless processing experiments. The Drop Tube Facility at Marshall Space Flight Center has played an important role in enhancing that area of research. Previous experiments performed in the Drop Tube with refractory metals has shown very interesting microstructural changes associated with deep undercoolings. It is apparent also that the microstructure of the deep undercooled species may be changing due to the release of the latent heat of fusion during recalescence. For scientific purposes, it is important to be able to differentiate between the microstructures of the two types of metallic species. A review of the literature shows that although significant advances have been made with respect to the engineering aspects of rapid solidification phenomena, there is still much to be learned in terms of understanding the basic phenomena. The two major ways in which rapid solidification processing provides improved structures and hence improved properties are: (1) production of refined structures such as fine dendrites and eutectics, and (2) production of new alloy compositions, microstructures, and phases through extended solid solubility, new phase reaction sequences, and the formation of metallic-glass microstructures. The objective of this work has been to determine the optimal methodology required to extract this excess energy without affecting the thermo-physical parameters of the under-cooled <span class="hlt">melt</span>. In normal containerless processing experiments recalescence occurs as the <span class="hlt">melt</span> returns toward the <span class="hlt">melting</span> point in order to solidify. A new type of experiment is sought in which the resultant microstructure of the undercooled species is frozen in without going through the <span class="hlt">melting</span> point regime and subsequent near equilibrium solidification of the remaining liquid. This experimental approach entails the design of an appropriate <span class="hlt">melt</span> spinning system which is compatible with Drop Tube operations and processing constraints. That work is the goal of this study.</p> <div class="credits"> <p class="dwt_author">Workman, Gary L.; Rathz, Thomas</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">229</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10131134"> <span id="translatedtitle">Consequences of tritium release to water pathways from <span class="hlt">postulated</span> accidents in a DOE production reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A full-scale PRA of a DOE production reactor has been completed that considers full release of tritium as part of the severe accident source term. Two classes of <span class="hlt">postulated</span> reactor accidents, a loss-of-moderator pumping accident and a loss-of-coolant accident, are used to bound the expected dose consequence from liquid pathway release. Population doses from the radiological release associated with the two accidents are compared for aqueous discharge and atmospheric release modes. The expectation values of the distribution of possible values for the societal effective dose equivalent to the general public, given a tritium release to the atmosphere, is 2.8 person-Sv/PBq (9.9 {times} 10{sup {minus}3} person-rem/Ci). The general public drinking water dose to downstream water consumers is 6.5 {times} 10{sup {minus}2} person-Sv/Pbq (2.4 {times} 10{sup {minus}4} person-rem/Ci) for aqueous releases to the surface streams eventually reaching the Savannah River. Negligible doses are calculated for freshwater fish and saltwater invertebrate consumption, irrigation, and recreational use of the river, given that an aqueous release is assumed to occur. Relative to the balance of fission products released in a hypothetical severe accident, the tritium-related dose is small. This study suggests that application of regional models (1610 km radius) will indicate larger dose consequences from short-term tritium release to the atmosphere than from comparable tritium source terms to water pathways. However, the water pathways assessment is clearly site-specific, and the overall aqueous dose will be dependent on downstream receptor populations and uses of the river.</p> <div class="credits"> <p class="dwt_author">O`Kula, K.R.; Olson, R.L.; Hamby, D.M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-12-31</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">230</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5768009"> <span id="translatedtitle">Consequences of tritium release to water pathways from <span class="hlt">postulated</span> accidents in a DOE production reactor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A full-scale PRA of a DOE production reactor has been completed that considers full release of tritium as part of the severe accident source term. Two classes of <span class="hlt">postulated</span> reactor accidents, a loss-of-moderator pumping accident and a loss-of-coolant accident, are used to bound the expected dose consequence from liquid pathway release. Population doses from the radiological release associated with the two accidents are compared for aqueous discharge and atmospheric release modes. The expectation values of the distribution of possible values for the societal effective dose equivalent to the general public, given a tritium release to the atmosphere, is 2.8 person-Sv/PBq (9.9 {times} 10{sup {minus}3} person-rem/Ci). The general public drinking water dose to downstream water consumers is 6.5 {times} 10{sup {minus}2} person-Sv/Pbq (2.4 {times} 10{sup {minus}4} person-rem/Ci) for aqueous releases to the surface streams eventually reaching the Savannah River. Negligible doses are calculated for freshwater fish and saltwater invertebrate consumption, irrigation, and recreational use of the river, given that an aqueous release is assumed to occur. Relative to the balance of fission products released in a hypothetical severe accident, the tritium-related dose is small. This study suggests that application of regional models (1610 km radius) will indicate larger dose consequences from short-term tritium release to the atmosphere than from comparable tritium source terms to water pathways. However, the water pathways assessment is clearly site-specific, and the overall aqueous dose will be dependent on downstream receptor populations and uses of the river.</p> <div class="credits"> <p class="dwt_author">O'Kula, K.R.; Olson, R.L.; Hamby, D.M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">231</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..1613578S"> <span id="translatedtitle">Phenocrystal variations in <span class="hlt">melt</span> rocks from Tenoumer impact crater, Mauretania: indicators for varying target contribution and <span class="hlt">melt</span> mixing.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Impact <span class="hlt">melt</span> rocks from the relatively small (1.9 km in diameter) Tenoumer impact crater (Mauretania) show heterogeneities regarding whole rock chemistry, lithoclast components, their shock deformation degree, amount of vesiculation (<span class="hlt">melt</span> degassing), and contribution of carbonate <span class="hlt">melt</span> phases mingled into silicate <span class="hlt">melt</span> matrix. These heterogeneities have two main reasons: First, due to the restricted size of the impact crater there was probably no coherent <span class="hlt">melt</span> pool where a homogeneous mixture of the target rocks could be achieved. Therefore, impact <span class="hlt">melting</span> of target lithologies resulted in locally different, often incomplete mixing of <span class="hlt">melts</span> from chemically very diverse target rocks. Second, <span class="hlt">melt</span> rock heterogeneity occurs at the thin section scale and is due to fast cooling during and after the dynamic ejection and emplacement process. The overall period of crystal growth has been extremely short, so that chemical equilibration of the phases could not be achieved. <span class="hlt">Melt</span> mixing processes involved in impact <span class="hlt">melt</span> formation are, thus, recorded in non-equilibrium growth features. Mixing processes between chemically different <span class="hlt">melt</span> phases and the formation of hybrid <span class="hlt">melts</span> can be observed in the case of Tenoumer impact <span class="hlt">melts</span> on a millimeter scale. Due to extreme cooling rates, different mixing stages are preserved in the varied parageneses and mineral chemistry of phenocrysts. Different silicate <span class="hlt">melt</span> matrices show different phenocryst parageneses in response to slight variation of whole-rock chemistry and, thus, represents a useful indicator of precursor rock contribution to different impact <span class="hlt">melts</span>. Basalt-andesitic (Mg,Fe-rich) <span class="hlt">melt</span> matrices are after all composed of up to 20 vol% of forsterite-rich olivine-microphenocrysts. Decreasing Fe,Mg-amounts of <span class="hlt">melt</span> matrix results in decreasing modal abundance of olivine, which shows progressively higher fayalite composition. These observations correlate with changing amounts of felsic and basic lithoclasts (granite, granitic gneiss, and gabbro). Different pyroxene generations occur including significant compositional zonation with widely variable CaO, MgO and FeO contents (En7-80, Wo4-50, Fs9-41). Pyroxene evolution (<span class="hlt">core</span>-rim-zonation) changes from En-Di to Di-Hd as CaO content of the <span class="hlt">melt</span> matrix oversteps 9 wt%. Strong variations in CaO content that do not correlate with increasing MgO and FeO contents are interpreted as incorporation of CaO from carbonate <span class="hlt">melts</span> into the silicate <span class="hlt">melt</span> phase. The presents of intermingled carbonate <span class="hlt">melt</span> schlieren support this hypothesis. New 40Ar/39Ar dating on three of the studied <span class="hlt">melt</span> rock samples resulted in a - preferred - age of 1.57 ± 0.14 Ma for the Tenoumer impact event. This impact age is significantly different from previous dating results of 21 ± 10 ka and 2.5 ± 0.5 Ma.</p> <div class="credits"> <p class="dwt_author">Schultze, Dina; Jourdan, Fred; Hecht, Lutz; Reimold, Uwe</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">232</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26599492"> <span id="translatedtitle"><span class="hlt">Melt</span> quenching and coolability by water injection from below: Co-injection of water and non-condensable gas</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The interaction and mixing of high-temperature <span class="hlt">melt</span> and water is the important technical issue in the safety assessment of water-cooled reactors to achieve ultimate <span class="hlt">core</span> coolability. For specific advanced light water reactor (ALWR) designs, deliberate mixing of the <span class="hlt">core</span> <span class="hlt">melt</span> and water is being considered as a mitigative measure, to assure ex-vessel <span class="hlt">core</span> coolability. The goal of our work is</p> <div class="credits"> <p class="dwt_author">Dae H. Cho; Richard J. Page; Sherif H. Abdulla; Mark H. Anderson; Helge B. Klockow; Michael L. Corradini</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">233</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60448149"> <span id="translatedtitle">Assessment of the Environmental Impact of Tritium Release from Wolsong Tritium Removal Facility at the <span class="hlt">Postulated</span> Accident</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In Korea, Wolsong Tritium Removal Facility (WTRF) is scheduled to begin operation in 2005 to reduce the amount of tritium generated in the moderator and coolant. The objective of this study is to evaluate the environmental impact of tritium released from WTRF in the <span class="hlt">postulated</span> accident. In order to achieve this, a computer code was developed at KAIST (Korea Advanced</p> <div class="credits"> <p class="dwt_author">Daesik Yook; KunJai Lee; Hongsuk Chung</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">234</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60319343"> <span id="translatedtitle">Noble gas, iodine, and cesium transport in a <span class="hlt">postulated</span> loss of decay heat removal accident at Browns Ferry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This report presents an analysis of the movement of noble gas, iodine, and cesium fission products within the Mark-I containment BWR reactor system represented by Browns Ferry Unit 1 during a <span class="hlt">postulated</span> accident sequence initiated by a loss of decay heat removal capability following a scram. The event analysis showed that this accident could be brought under control by various</p> <div class="credits"> <p class="dwt_author">R. P. Wichner; S. A. Hodge; C. F. Weber; E. C. Beahm; A. L. Wright</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">235</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE92607598"> <span id="translatedtitle">Analysis with the code TANK of a <span class="hlt">postulated</span> reactivity-insertion transient in a 10-MW MAPLE research reactor.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">This report discusses the analysis of a <span class="hlt">postulated</span> loss-of-regulation (LOR) accident in a metal-fuelled MAPLE Research Reactor. The selected transient scenario involves a slow LOR from low reactor power; the control rods are assumed to withdraw slowly unt...</p> <div class="credits"> <p class="dwt_author">R. J. Ellis</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">236</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://qem.ee.nthu.edu.tw/f8c.pdf"> <span id="translatedtitle">A Wave Interpretation of the Compton Effect As a Further Demonstration of the <span class="hlt">Postulates</span> of de Broglie</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Compton effect is commonly cited as a demonstration of the particle feature of light, while the wave nature of matter has been proposed by de Broglie and demonstrated by Davisson and Germer with the Bragg diffraction of electron beams. In this investigation, we present an entirely different interpretation of the Compton effect based on the <span class="hlt">postulates</span> of de Broglie</p> <div class="credits"> <p class="dwt_author">Ching-Chuan Su</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">237</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52822957"> <span id="translatedtitle">Experimental studies of <span class="hlt">core</span> formation: Application to asteroidal bodies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The question of how metallic <span class="hlt">cores</span> form reduces to the fluid dynamic problem of understanding the surface tension between metallic <span class="hlt">melts</span> and silicates. This problem was addressed by performing experiments to determine the surface tensions between metallic <span class="hlt">melts</span> with variable S contents and silicate phases; olivine, for which data were presented last year; and orthopyroxene, for which we now have</p> <div class="credits"> <p class="dwt_author">M. A. Herpfer; J. W. Larimer</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">238</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pulseplanet.com/dailyprogram/dailies.php?POP=3390"> <span id="translatedtitle"><span class="hlt">Melting</span> Polar Icecap: Intro</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This two-minute sound segment introduces the problem of the <span class="hlt">melting</span> of the polar ice cap. A picture is beginning to emerge of a polar icecap that is both thinning and shrinking as a result of either a normal climate fluctuation or global warming. This site is from an archive of a daily radio program called Pulse of the Planet, which provides its listeners with a portrait of Planet Earth, tracking the rhythms of nature, culture and science worldwide and blending interviews and extraordinary natural sound. The site also provides a written transcript of the broadcast.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2005-02-25</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">239</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013E%26PSL.368..219R"> <span id="translatedtitle">A comment on "Experimental determination of carbon isotope fractionation between iron carbide <span class="hlt">melt</span> and carbon: 12C-enriched carbon in the Earth's <span class="hlt">core</span>?" by M. Satish-Kumar, H. So, T. Yoshino, M. Kato, Y. Hiroi [Earth Planet. Sci. Lett. 310 (2011) 340-348</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Accounting for the behavior of metastable and stable phases in the Fe-C system at HPHT allows a reconsideration of the results of Satish-Kumar et al. (2011). The occurrence of a metastable Fe-Gr eutectic explains the "lowering of the phase boundaries" as well as the presence of <span class="hlt">melt</span> in experiments below the Fe-Fe3C eutectic temperature. Overall, the data reported evidence for graphite interaction with carbon dissolved in the iron <span class="hlt">melt</span> which does not represent an "iron carbide <span class="hlt">melt</span>". The results are in good agreement with previously published data on carbon isotope effect between crystalline carbon and carbon solution in metal <span class="hlt">melt</span>.</p> <div class="credits"> <p class="dwt_author">Reutsky, V. N.; Borzdov, Yu. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">240</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFM.V51D..06T"> <span id="translatedtitle">Viscosity of Anhydrous and Hydrous Basalt <span class="hlt">Melts</span> at High Pressures</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We performed in situ falling-sphere experiments to determine the viscosity of anhydrous and hydrous basaltic (48 wt% SiO2) <span class="hlt">melts</span> from 1.5 to 5.3 GPa between 1600 and 1840 K, using the T-25 MA8 multianvil apparatus at the GSECARS 13-ID-D beamline at the Advanced Photon Source, Argonne National Lab. These falling-sphere experiments included monitoring the simultaneous settling of Pt and Mo spheres, an approach that provides redundant viscosity measurements for individual experiments and offers the opportunity to recover simultaneously <span class="hlt">melt</span> density. Our results show that the viscosity of anhydrous basalt <span class="hlt">melt</span> decreases with pressure up to 5.3 GPa, with an activation volume for viscous flow of -8.1 to -9.5 cm3/mol between 2 and 5.3 GPa. The addition of a few wt. % water reduces <span class="hlt">melt</span> viscosity by roughly 0.5 log units; however, there is no resolvable influence on activation volume. This negative pressure dependence is consistent with previous results for basaltic <span class="hlt">melts</span> up to 3 GPa [1, 2], while the activation volume at low pressure is indistinguishable from the activation volume for O self-diffusion in the same bulk composition [3]. Application of the Eyring equation using O self-diffusion data for basaltic <span class="hlt">melt</span> [3] predicts anhydrous <span class="hlt">melt</span> viscosities that are 30-90% of the values determined in this study. This result is in stark contrast with our recent results for dacitic <span class="hlt">melt</span> (68 wt% SiO2) <span class="hlt">melt</span> [4], in which the Eyring equation overestimates viscosity by as much as 40% at pressures < 5 GPa. The limited utility of the Eyring equation for naturally-occurring silicate <span class="hlt">melts</span> illustrates the difficulties in relating O self-diffusion to viscous flow in polymerized liquids. Adam-Gibbs theory [5] provides a means for addressing structural controls on these transport properties. The negative pressure dependence for anhydrous and hydrous basalt viscosity suggests that the extraction of partial <span class="hlt">melts</span> from mantle source regions will be enhanced with pressure to 5.3 GPa. Future work will extend these observations to higher pressures in an effort to constrain <span class="hlt">melt</span> transport properties approaching conditions for the top of the transition zone where [6] have <span class="hlt">postulated</span> the accumulation of a dense hydrous <span class="hlt">melt</span> layer as a result of dehydration <span class="hlt">melting</span> of transition zone material. [1] Fujii, T, Kushiro, I (1977) CIW Yrbk., 76, 419-424; [2] Ando, R, et al. (2003) SPring-8 report No. 11, 45; [3] Lesher et al. (1996) GCA, 60, 405-413; [4] Tinker et al. (2004) Am. Min., in press; [5] Adam, G, Gibbs, JH (1965) J. Chem. Phys., 43, 139-146; [6] Bercovici, D, Karato, S-I (2003) Nature, 425, 39-44</p> <div class="credits"> <p class="dwt_author">Tinker, D.; Lesher, C. E.; Baxter, G. M.; Uchida, T.; Wang, Y.; Zhao, Y.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_11");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return 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href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a style="font-weight: bold;">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_14");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">241</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/1006097"> <span id="translatedtitle">Rheology and Microstructure of Entangled Polymer Nanocomposite <span class="hlt">Melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The rheology and microstructure of 44 nm diameter silica particles suspended in entangled poly(ethylene oxide) (PEO) <span class="hlt">melts</span> are studied through measurement of filled <span class="hlt">melt</span> viscosity and X-ray scattering measurement of interparticle structure factors, S(q,{phi}{sub c}), where q is the scattering vector and {phi}{sub c} is the silica volume fraction. The particles have a similar refractive index to PEO which minimizes van der Waals attractions acting between particles. The introduction of particles causes an elevation in the viscosity of the nanocomposite <span class="hlt">melt</span> more than would be expected of particles merely interacting with hard <span class="hlt">core</span> repulsions. Further addition of particles causes a rise in the elastic and viscous moduli. The rheological characterization of these nanocomposite <span class="hlt">melts</span> is discussed in terms of several critical particle volume fractions that result from confinement of polymer, adsorption of polymer segments to the particle surface, and overlap and entanglement of adsorbed polymer as the particle volume fraction is increased. Characterization of the particle microstructure shows that the association of the polymer with the particles drives the particles to structure more than would be expected of particles with interactions governed merely by hard <span class="hlt">core</span> repulsions. Particles show signs of instability in the polymer <span class="hlt">melt</span> at a common elevated volume fraction independent of polymer molecular weight.</p> <div class="credits"> <p class="dwt_author">Anderson, Benjamin J.; Zukoski, Charles F.; (UIUC)</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-03-16</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">242</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ulapland.fi/home/hkunta/jmoore/pdfs/Isaksson42A073.pdf"> <span id="translatedtitle">ice <span class="hlt">core</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Svalbard ice <span class="hlt">cores</span> have not yet been fully exploited for studies of climate and environmental conditions. In one recently drilled ice <span class="hlt">core</span> from Lomonosovfonna we have studied the methanesulphonic acid (MSA) records in relation to temperature and sea ice. During the present climatic conditions MSA appears to be negatively correlated with the sea ice conditions in the Barents Sea, and</p> <div class="credits"> <p class="dwt_author">Elisabeth Isaksson; Teija Kekonen; John Moore</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">243</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17878541"> <span id="translatedtitle">Analysis of <span class="hlt">melt</span> copolymers.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Melt</span> copolymer chains are the main (most abundant) reaction product obtained when heating a blend of two (or more) condensation polymers (such as polyester + polycarbonate or polyester + polyamide or polyester + polyester) in which exchange reactions occur. In fact, during the <span class="hlt">melt</span>-mixing reaction, an AB copolymer is formed and, as a consequence, the sample is a complex mixture made of three components or simply "parts", referred to as Z1, Z2 and Z3, where Z1 and Z2 are the parts for unreacted homopolymers (A and B), whereas Z3 is the part for the copolymer. In this paper, it is shown that matrix-assisted laser desorption/ionization mass spectrometry (and mass spectrometry in general) can be used to monitor the yield of the reactive blending reaction, YR, by measuring the amount of unreacted homopolymer (Z1 and Z2). In order to allow for comparisons, the paper also discusses conventional methods for measuring Z1 and Z2, such as liquid chromatography and nuclear magnetic resonance. PMID:17878541</p> <div class="credits"> <p class="dwt_author">Montaudo, Maurizio S</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">244</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20030111215&hterms=liquid+crystal+pdf&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dliquid%2Bcrystal%2Bpdf"> <span id="translatedtitle"><span class="hlt">Melt</span> Redistribution in Dynamic Systems: Applications to <span class="hlt">Core</span> Formation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Samples of olivine + Fe-S were fabricated by hot-pressing a mechanical mixture of the two phases. Olivine powders with a starting grain size of approx. 10 microns were prepared by crushing crystals of San Carlos olivine followed by pulverization in a fluid energy mill. Iron sulfide powder with a particle size of approx. 5 microns was prepared from a 2:1 mixture of reagent grade iron sulfide (FeS) plus iron. Rods 20 mm in length by 10 mm in diameter were cold-pressed into iron capsules with a uniaxial stress of approx. 200 MPa. These rods were then hot-pressed at 1523 K and 300 MPa for 4 h to obtain a starting material with <2% porosity. Samples for shear experiments were cut perpendicular to the long axis of these rods. The discs were shaped into ellipses approx. 6 mm by approx. 8 mm with a thickness ranging from 0.6 to 1.0 mm. An iron foil strain marker was inserted into a cut made along the minor axis. The sample was placed between two thoriated tungsten pistons cut at 45 deg to the long axis and then placed into an iron sleeve capped by alumina discs. The sample was then sheared in a gas pressure-medium apparatus at a temperature of 1523 K and a confining pressure of 300 MPa.</p> <div class="credits"> <p class="dwt_author">Hustoft, J. W.; Kohlstedt, D. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">245</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1993spma.rept..205E"> <span id="translatedtitle">Advances in plasma <span class="hlt">melting</span> technology</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The quest for 'defect-free' high performance metals has benefited from the expansion of plasma hearth <span class="hlt">melting</span> capacity. 'Skull' <span class="hlt">melting</span> in water-cooled copper containers under an inert gas atmosphere allows elimination of ceramic and refractory metal inclusions when <span class="hlt">melting</span> reactive metals and superalloys, while retaining the input alloy content. The interactions of operating variables such as furnace pressure, nature of gas, arc current and heat input pattern with product properties such as homogeneity, grain size, and inclusions are described. By proper process control, plasma hearth <span class="hlt">melting</span> has been qualified as one of only two processes suitable for particularly demanding rotating grade engine parts made of titanium alloy. Costs of plasma hearth <span class="hlt">melting</span> are less than with electron beam. Extension of plasma processing to other alloys is being actively pursued. Powder production is currently practical with plasma <span class="hlt">melting</span> and bottom pouring to make powder. Some speculations on future trends in materials and operating temperatures are offered.</p> <div class="credits"> <p class="dwt_author">Eschenbach, R.; Hoffelner, W.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">246</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/945774"> <span id="translatedtitle"><span class="hlt">Melting</span> of Ice under Pressure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The <span class="hlt">melting</span> of ice under pressure is investigated with a series of first principles molecular dynamics simulations. In particular, a two-phase approach is used to determine the <span class="hlt">melting</span> temperature of the ice-VII phase in the range of 10 to 50 GPa. Our computed <span class="hlt">melting</span> temperatures are consistent with existing diamond anvil cell experiments. We find that for pressures between 10 to 40 GPa, ice <span class="hlt">melts</span> as a molecular solid. For pressures above {approx}45 GPa there is a sharp increase in the slope of the <span class="hlt">melting</span> curve due to the presence of molecular dissociation and proton diffusion in the solid, prior to <span class="hlt">melting</span>. The onset of significant proton diffusion in ice-VII as a function of increasing temperature is found to be gradual and bears many similarities to that of a type-II superionic solid.</p> <div class="credits"> <p class="dwt_author">Schwegler, E; Sharma, M; Gygi, F; Galli, G</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-07-31</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">247</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2547417"> <span id="translatedtitle"><span class="hlt">Melting</span> of ice under pressure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The <span class="hlt">melting</span> of ice under pressure is investigated with a series of first-principles molecular dynamics simulations. In particular, a two-phase approach is used to determine the <span class="hlt">melting</span> temperature of the ice-VII phase in the range of 10–50 GPa. Our computed <span class="hlt">melting</span> temperatures are consistent with existing diamond anvil cell experiments. We find that for pressures between 10 and 40 GPa, ice <span class="hlt">melts</span> as a molecular solid. For pressures above ?45 Gpa, there is a sharp increase in the slope of the <span class="hlt">melting</span> curve because of the presence of molecular dissociation and proton diffusion in the solid before <span class="hlt">melting</span>. The onset of significant proton diffusion in ice-VII as a function of increasing temperature is found to be gradual and bears many similarities to that of a type-II superionic solid.</p> <div class="credits"> <p class="dwt_author">Schwegler, Eric; Sharma, Manu; Gygi, Francois; Galli, Giulia</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">248</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003AdSpR..32..237G"> <span id="translatedtitle"><span class="hlt">Melting</span> processes under microgravity conditions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The kinetics of <span class="hlt">melting</span> pivalic acid (PVA) dendrites was observed under convection-free conditions on STS-87 as part of the United States Microgravity Payload Mission (USMP-4) flown on Columbia in 1997. Analysis of video data show that PVA dendrites <span class="hlt">melt</span> without relative motion with respect to the quiescent <span class="hlt">melt</span> phase. Dendritic fragments display shrinking to extinction, with fragmentation occurring at higher initial supercoblings. Individual fragments follow a characteristic time-dependence derived elsewhere. The microgravity <span class="hlt">melting</span> kinetics against which the experimental observations are compared is based on conduction-limited quasi-static <span class="hlt">melting</span> under shape-preserving conditions. Agreement between analytic theory and our experiments is found when the <span class="hlt">melting</span> process occurs under shape-preserving conditions as measured using the C/A ratio of individual needle-like crystal fragments.</p> <div class="credits"> <p class="dwt_author">Glicksman, M. E.; Lupulescu, A.; Koss, M. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">249</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61283970"> <span id="translatedtitle">Chemical phenomena and fission product behavior during <span class="hlt">core</span> debris\\/concrete interactions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The importance of chemical processes to the prediction of <span class="hlt">core</span> debris interactions with concrete and associated aerosol generation is discussed. Some chemical processes that should be considered in improving existing models are described. Chemical processes could make the metal phase of <span class="hlt">core</span> debris more dense than the oxide phase. Speciation of the <span class="hlt">melt</span> can affect the apparent activity of <span class="hlt">melt</span></p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">250</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFMDI42A..08B"> <span id="translatedtitle">The Infidelity of <span class="hlt">Melt</span> Inclusions?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Melt</span> inclusions are routinely used as evidence of magmatic compositions prior to volcanic eruptions. However, it has long been known that kinetic processes can modify <span class="hlt">melt</span> inclusion compositions during trapping. We investigated the fidelity of <span class="hlt">melt</span> inclusions as records of magmatic compositions by artificially creating <span class="hlt">melt</span> inclusions through crystallization of plagioclase and clinopyroxene from a hawaiitic basalt bulk composition at 1.0 GPa, 1150 °C, or 75 °C undercooling. We compared <span class="hlt">melt</span> inclusion compositions to those of <span class="hlt">melts</span> 100's of ?m away from the crystals and found measurable differences in the compositions. We modeled the concentration profiles of Al, Fe, P, S, and Cl in front of the crystals using classical impurity rejection theory during growth at a constant rate followed by a growth hiatus during which diffusive relaxation occurred. The values of the growth rates and times were constrained by measured crystal sizes and the experimental duration. The diffusion coefficients for the elements investigated were either calculated from transition state theory (Al, Fe) or measured in the same bulk composition as that used for this study (S and Cl from the literature, new measurements for P). An envelope of models bracket the observed compositional profiles of the elements studied and predict enrichments, or depletions, at the crystal-<span class="hlt">melt</span> interface that are quantitatively similar to those seen in the <span class="hlt">melt</span> inclusions. The differences between the <span class="hlt">melt</span> far from the crystals and that at the interface are only 20% (relative) for the major elements, Al, Fe, but are about 50% for S and Cl and can exceed 100% for P. These differences correlate with the relative chemical diffusion coefficients of these ions in the <span class="hlt">melt</span>. Based upon these experiments and models we advise caution in the use of <span class="hlt">melt</span> inclusions as indicators of pre-eruptive <span class="hlt">melt</span> compositions.</p> <div class="credits"> <p class="dwt_author">Baker, D. R.; Freda, C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">251</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/975674"> <span id="translatedtitle"><span class="hlt">Melting</span> and spheroidization of hexagonal boron nitride in a microwave-powered, atmospheric pressure nitrogen plasma `</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We have developed a method for producing spherically-shaped, hexagonal phase boron nitride (hBN) particles of controlled diameter in the 10-100 micron size range. Specifically, platelet-shaped hBN particles are passed as an aerosol through a microwave-generated, atmospheric pressure, nitrogen plasma. In the plasma, agglomerates formed by collisions between input hBN particles, <span class="hlt">melt</span> and forms spheres. We <span class="hlt">postulate</span> that this unprecedented process takes place in the unique environment of a plasma containing a high N-atom concentration, because in such an environment the decomposition temperature can be raised above the <span class="hlt">melting</span> temperature. Indeed, given the following relationship [1]: BN{sub (condensed)} {leftrightarrow} B{sub (gas)} + N{sub (gas)}. Standard equilibrium thermodynamics indicate that the decomposition temperature of hBN is increased in the presence of high concentrations of N atoms. We <span class="hlt">postulate</span> that in our plasma system the N atom concentration is high enough to raise the decomposition temperature above the (undetermined) <span class="hlt">melting</span> temperature. Keywords Microwave plasma, boron nitride, <span class="hlt">melting</span>, spherical, thermodynamics, integrated circuit package.</p> <div class="credits"> <p class="dwt_author">Gleiman, S. S. (Seth S.); Phillips, J. (Jonathan)</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">252</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55121420"> <span id="translatedtitle">Solid-liquid boundaries in iron-rich alloys and the age of the Earth's inner <span class="hlt">core</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Melting</span> and solidification cause major chemical differentiation in the Earth. As the Earth cools, the liquid <span class="hlt">core</span> solidifies from the center and the inner <span class="hlt">core</span> grows at the expense of the outer <span class="hlt">core</span>. The timing of the onset of <span class="hlt">core</span> solidification remains poorly constrained. Labrosse et al. (2001) estimated the age of the Earth's inner <span class="hlt">core</span> based on energy budget</p> <div class="credits"> <p class="dwt_author">J. Li; B. Chen; L. Gao</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">253</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013LTP....39..427Y"> <span id="translatedtitle"><span class="hlt">Melting</span> line of polymeric nitrogen</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We made an attempt to predict location of the <span class="hlt">melting</span> line of polymeric nitrogen using two equations for Helmholtz free energy: proposed earlier for cubic gauche-structure and developed recently for liquid polymerized nitrogen. The P-T relation, orthobaric densities and latent heat of <span class="hlt">melting</span> were determined using a standard double tangent construction. The estimated <span class="hlt">melting</span> temperature decreases with increasing pressure, alike the temperature of molecular-nonmolecular transition in solid. We discuss the possibility of a triple point (solid-molecular fluid-polymeric fluid) at ~80 GPa and observed maximum of <span class="hlt">melting</span> temperature of nitrogen.</p> <div class="credits"> <p class="dwt_author">Yakub, L. N.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">254</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002cosp...34E1273G"> <span id="translatedtitle"><span class="hlt">Melting</span> processes under microgravity conditions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Rensselaer Isothermal Dendritic Growth Experiment (RIDGE) uses the large data archive amassed through a series of three NASA-supported microgravity experiments (IDGE/USMP-2, -3, and -4), all of which flew aboard the space shuttle Columbia. The IDGE instruments aboard USMP-2 and -3 provided in-flight CCD images, and 35-mm films (postflight). USMP-4 also allowed streaming of near-real-time video. Using 30 fps video data, it became possible for the first time to study both freezing and <span class="hlt">melting</span> sequences for high-purity pivalic acid (PVA). We report on the <span class="hlt">melting</span> process observed for PVA crystal fragments, observed under nearly ideal convection-free conditions. Conduction-limited <span class="hlt">melting</span> processes are of importance in orbital <span class="hlt">melting</span> of materials, meteoritic genesis, mushy-zone evolution, and in fusion weld pools where length scales for thermal buoyancy are restricted. Microgravity video show clearly that PVA dendrites <span class="hlt">melt</span> into fragments that shrink at accelerating rates to extinction. The <span class="hlt">melting</span> paths of individual fragments follow characteristic time dependences derived from theory. The theoretical <span class="hlt">melting</span> kinetics against which the experimental observations are carefully compared is based on conduction-limited quasi-static <span class="hlt">melting</span> under shape-preserving conditions. Good agreement between theory and experiment is found for the stable <span class="hlt">melting</span> of needle-shaped prolate spheroidal PVA crystal fragments with aspect ratios near C /A = 12.</p> <div class="credits"> <p class="dwt_author">Glicksman, M.; Lupulescu, A.; Koss, M.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">255</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5138100"> <span id="translatedtitle">Formation and characterization of fission-product aerosols under <span class="hlt">postulated</span> HTGR accident conditions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The paper presents the results of an experimental investigation on the formation mechanism and physical characterization of simulated nuclear aerosols that could likely be released during an HTGR <span class="hlt">core</span> heat-up accident. Experiments were carried out in a high-temperature flow system consisting essentially of an inductively heated release source, a vapor deposition tube, and a filter assembly for collecting particulate matter. Simulated fission products Sr and Ba as oxides are separately impregnated in H451 graphite wafers and released at elevated temperatures into a dry helium flow. In the presence of graphite, the oxides are quantitatively reduced to metals, which subsequently vaporize at temperatures much lower than required for the oxides alone to vaporize in the absence of graphite. A substantial fraction of the released material is associated with particulate matter, which is collected on filters located downstream at ambient temperature. The release and transport of simulated fission product Ag as metal are also investigated.</p> <div class="credits"> <p class="dwt_author">Tang, I.N.; Munkelwitz, H.R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">256</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26598864"> <span id="translatedtitle"><span class="hlt">Core</span> loss during a severe accident (COLOSS)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The <span class="hlt">core</span> loss during a severe accident (COLOSS) project is a 3-year shared-cost action which started in February 2000. The project is concerned with the consequences that <span class="hlt">core</span> degradation, occurring under severe accident conditions, may have on H2 production, <span class="hlt">melt</span> generation and the source term. Unresolved in-vessel risk-relevant issues are studied, through a large number of experiments such as (a)</p> <div class="credits"> <p class="dwt_author">B Adroguer; P Chatelard; J. P Van Dorsselaere; C Duriez; N Cocuaud; L Bellenfant; D Bottomley; V Vrtilkova; K Mueller; W Hering; C Homann; W Krauss; A Miassoedov; M Steinbrück; J Stuckert; Z Hozer; G Bandini; J Birchley; T. v Berlepsch; M Buck; J. A. F Benitez; E Virtanen; S Marguet; G Azarian; H Plank; M Veshchunov; Y Zvonarev; A Goryachev</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">257</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EM%26P..111....1W"> <span id="translatedtitle">A <span class="hlt">Postulated</span> Planetary Collision, the Terrestrial Planets, the Moon and Smaller Solar-System Bodies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In a scenario produced by the Capture Theory of planetary formation, a collision between erstwhile solar-system giant planets, of masses 798.75 and 598.37 M ?, is simulated using smoothed-particle hydrodynamics. Due to grain-surface chemistry that takes place in star-forming clouds, molecular species containing hydrogen, with a high D/H ratio taken as 0.01, form a layer around each planetary <span class="hlt">core</span>. Temperatures generated by the collision initiate D-D reactions in these layers that, in their turn, trigger a reaction chain involving heavier elements. The nuclear explosion shatters and disperses both planets, leaving iron-plus-silicate stable residues identified as a proto-Venus and proto-Earth. A satellite of one of the colliding planets, captured or retained by the proto-Earth <span class="hlt">core</span>, gave the Moon; two massive satellites released into heliocentric orbits became Mercury and Mars. For the Moon and Mars, abrasion of their surfaces exposed to collision debris results in hemispherical asymmetry. Mercury, having lost a large part of its mantle due to massive abrasion, reformed to give the present high-density body. Debris from the collision gave rise to asteroids and comets, much of the latter forming an inner reservoir stretching outwards from the inner Kuiper Belt that replenishes the Oort Cloud when it is depleted by a severe perturbation. Other features resulting from the outcome of the planetary collision are the relationship of Pluto and Triton to Neptune, the presence of dwarf planets and light-atom isotopic anomalies in meteorites.</p> <div class="credits"> <p class="dwt_author">Woolfson, M. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">258</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014ApPhA.114.1303S"> <span id="translatedtitle"><span class="hlt">Melt</span> pool dynamics during selective electron beam <span class="hlt">melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Electron beam <span class="hlt">melting</span> is a promising additive manufacturing technique for metal parts. Nevertheless, the process is still poorly understood making further investigations indispensable to allow a prediction of the part's quality. To improve the understanding of the process especially the beam powder interaction, process observation at the relevant time scale is necessary. Due to the difficult accessibility of the building area, the high temperatures, radiation and the very high scanning speeds during the <span class="hlt">melting</span> process the observation requires an augmented effort in the observation equipment. A high speed camera in combination with an illumination laser, band pass filter and mirror system is suitable for the observation of the electron beam <span class="hlt">melting</span> process. The equipment allows to observe the <span class="hlt">melting</span> process with a high spatial and temporal resolution. In this paper the adjustment of the equipment and results of the lifetime and the oscillation frequencies of the <span class="hlt">melt</span> pool for a simple geometry are presented.</p> <div class="credits"> <p class="dwt_author">Scharowsky, T.; Osmanlic, F.; Singer, R. F.; Körner, C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">259</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60697717"> <span id="translatedtitle">Late-phase <span class="hlt">melt</span> progression experiment: MP2. Results and analysis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In-pile experiments addressing late-phase processes in Light Water Reactors (LWRs) were performed in the Annular <span class="hlt">Core</span> Research Reactor (ACRR) at Sandia National Laboratories. <span class="hlt">Melt</span> Progression (MP) experiments were designed to provide information to develop and verify computer models for analysis of LWR <span class="hlt">core</span> damage in severe accidents. Experiments examine the formation and motion of ceramic molten pools in disrupted reactor</p> <div class="credits"> <p class="dwt_author">R. D. Gasser; R. O. Gauntt; S. C. Bourcier</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">260</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010EOSTr..91V.504S"> <span id="translatedtitle">In Brief: <span class="hlt">Melting</span> glaciers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Glaciers in Patagonia and Alaska have been losing their mass, and for longer than glaciers elsewhere in the world, according to a 7 December report compiled by the United Nations Environment Programme (UNEP). “Climate change is causing significant mass loss of glaciers in high mountains worldwide,” notes the report, which calls for accelerated research, monitoring, and modeling of glaciers and snow and their role in water supplies. The report “also highlights the vulnerability and exposure of people dependent upon [glacier-fed] rivers to floods, droughts and eventually shortages as a result of changes in the <span class="hlt">melting</span> and freezing cycles linked with climate change and other pollution impacts,” according to UNEP executive director Achim Steiner. For more information, visit http://www.grida.no/publications/high­mountain-glaciers/.</p> <div class="credits"> <p class="dwt_author">Showstack, Randy; Tretkoff, Ernie</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_12");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' 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showDiv("page_15");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">261</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFM.V13C2051A"> <span id="translatedtitle">Eutectic <span class="hlt">melting</span> temperature of the lowermost Earth's mantle</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Partial <span class="hlt">melting</span> of the Earth's deep mantle probably occurred at different stages of its formation as a consequence of meteoritic impacts and seismology suggests that it even continues today at the <span class="hlt">core</span>-mantle boundary. <span class="hlt">Melts</span> are important because they dominate the chemical evolution of the different Earth's reservoirs and more generally the dynamics of the whole planet. Unfortunately, the most critical parameter, that is the temperature profile inside the deep Earth, remains poorly constrained accross the planet history. Experimental investigations of the <span class="hlt">melting</span> properties of materials representative of the deep Earth at relevant P-T conditions can provide anchor points to refine past and present temperature profiles and consequently determine the degree of <span class="hlt">melting</span> at the different geological periods. Previous works report <span class="hlt">melting</span> relations in the uppermost lower mantle region, using the multi-anvil press [1,2]. On the other hand, the pyrolite solidus was determined up to 65 GPa using optical observations in the laser-heated diamond anvil cell (LH-DAC) [3]. Finally, the <span class="hlt">melting</span> temperature of (Mg,Fe)2SiO4 olivine is documented at <span class="hlt">core</span>-mantle boundary (CMB) conditions by shock wave experiments [4]. Solely based on these reports, experimental data remain too sparse to draw a definite <span class="hlt">melting</span> curve for the lower mantle in the relevant 25-135 GPa pressure range. We reinvestigated <span class="hlt">melting</span> properties of lower mantle materials by means of in-situ angle dispersive X-ray diffraction measurements in the LH-DAC at the ESRF [5]. Experiments were performed in an extended P-T range for two starting materials: forsterite and a glass with chondrite composition. In both cases, the aim was to determine the onset of <span class="hlt">melting</span>, and thus the eutectic <span class="hlt">melting</span> temperatures as a function of pressure. <span class="hlt">Melting</span> was evidenced from drastic changes of diffraction peak shape on the image plate, major changes in diffraction intensities in the integrated pattern, disappearance of diffraction rings, and changes in the relation between sample-temperature and laser-power. In this work, we show that temperatures higher than 4000 K are necessary for <span class="hlt">melting</span> mean mantle at the 135 GPa pressure found at the <span class="hlt">core</span> mantle boundary (CMB). Such temperature is much higher than that from estimated actual geotherms. Therefore, <span class="hlt">melting</span> at the CMB can only occur if (i) pyrolitic mantle resides for a very long time in contact with the outer <span class="hlt">core</span>, (ii) the mantle composition is severely affected by additional elements depressing the solidus such as water or (iii) the temperature gradient in the D" region is amazingly steep. Other implications for the temperature state and the lower mantle properties will be presented. References (1) Ito et al., Phys. Earth Planet. Int., 143-144, 397-406, 2004 (2) Ohtani et al., Phys. Earth Planet. Int., 100, 97-114, 1997 (3) Zerr et al., Science, 281, 243-246, 1998 (4) Holland and Ahrens, Science, 275, 1623-1625, 1997 (5) Schultz et al., High Press. Res., 25, 1, 71-83, 2005.</p> <div class="credits"> <p class="dwt_author">Andrault, D.; Lo Nigro, G.; Bolfan-Casanova, N.; Bouhifd, M.; Garbarino, G.; Mezouar, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">262</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005JCrGr.276..549L"> <span id="translatedtitle">Conduction-limited crystallite <span class="hlt">melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">High-purity pivalic acid (PVA) dendrites were observed growing under convection-free conditions during the isothermal dendritic growth experiment (IDGE) flown on NASA's space shuttle Columbia on STS-87. The IDGE was part of the complement of primary scientific experiments designated as the United States Microgravity Payload Mission (USMP4) launched late in 1997. The IDGE video data show that PVA dendrites may be <span class="hlt">melted</span> without exhibiting any detectable relative motion with respect to the surrounding quiescent <span class="hlt">melt</span> phase. Thus, <span class="hlt">melting</span> occurs by heat conduction alone. When a small fixed superheating is imposed on pre-existing dendritic fragments, they <span class="hlt">melt</span> steadily toward extinction. Individual fragments steadily decrease in size according to a square-root of time dependence predicted using quasi-static conduction-limited theory. Agreement between analytic <span class="hlt">melting</span> theory and microgravity experiments was found originally if the <span class="hlt">melting</span> process occurs under the restriction of shape-preserving conditions, where needle-like crystal fragments may be approximated as ellipsoids with a constant axial ratio. Among the new results reported here is the influence of capillarity effects on <span class="hlt">melting</span> in needle-like crystallites, observed as a dramatic change in their axial ratio, when the size scale of a crystallite decreases below a critical value. In microgravity <span class="hlt">melting</span> experiments, the axial ratio of individual crystallites does not remain constant, because of interactions with neighboring fragments within the mushy zone. The kinetic data were then "sectorized" to divide the total <span class="hlt">melting</span> process into a series of short intervals. Each <span class="hlt">melting</span> sector for a crystallite could then be approximated by a constant average value of the axial ratio. Sectorization also allows accurate prediction of <span class="hlt">melting</span> kinetics by applying quasi-static heat conduction theory, despite the suspected presence of capillarity and the occurrence of fragmentation. These additional processes that accompany the <span class="hlt">melting</span> of slender crystallites currently lie outside conventional <span class="hlt">melting</span> theory. The data presented show that <span class="hlt">melting</span> kinetics of small crystallites remains dominated by heat conduction from the surrounding <span class="hlt">melt</span>, which is modified by the appearance of additional heat fluxes. These additional heat fluxes flow within the crystallites. They arise from capillary effects induced by steep interfacial curvature gradients that accompany the small crystallite size scales prior to their extinction.</p> <div class="credits"> <p class="dwt_author">Lupulescu, A.; Glicksman, M. E.; Koss, M. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">263</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005PhDT.......184C"> <span id="translatedtitle"><span class="hlt">Melting</span> phenomena in polymer blending</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This study is focused on understanding of the <span class="hlt">melting</span> process of polymer blends during blending. Four topics are addressed in this thesis: <span class="hlt">melting</span> behavior of polymer blends in an extruder, heat transfer between a solid polymer pellet and polymer <span class="hlt">melt</span>; rheological properties of polymer <span class="hlt">melt</span> suspensions; and morphology development of polymer blends during <span class="hlt">melting</span>. A barrel sliding mechanism and a perturbation method was used to investigate the <span class="hlt">melting</span> behavior of polypropylene (PP) and polystyrene (PS) blends in the extruder. It was found that the <span class="hlt">melting</span> process in the extruder could be divided into three distinct regions. Most of <span class="hlt">melting</span> occurred in the transition region mainly due to mechanical energy input. Friction between solid polymer pellets played a critical role in converting mechanical energy into heat. The location of the transition region for each process could be determined from the on-line visualization results, temperature and pressure profiles, and the perturbation signals. A representative heat transfer coefficient between a solid polymer pellet and another polymer <span class="hlt">melt</span> under shear flow was obtained as 250W/m2 · K through numerical simulations. The dynamics of thermocouple used in the experiment was captured using a first order process approximation. A good match was achieved between the simulation and experiment after taking the thermocouple dynamics into account. Suspensions of ethylene acrylate copolymer (EAC) <span class="hlt">melt</span> with PS beads were used to study rheological properties of polymer flow during extrusion. It was found that deformation of PS beads under high local shear stress could result in the decrease of the relative viscosity with increasing volume fraction. On-line visualization in a TSE showed an "erosion" mechanism for polycarbonate (PC) drop deformation and breakup in polyethylene (PE) <span class="hlt">melt</span>. This "erosion" mechanism was also found from corresponding numerical simulations. Stress peaks at the interface from simulation result could explain the "erosion" mechanism.</p> <div class="credits"> <p class="dwt_author">Chen, Hongbing</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">264</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19780057183&hterms=gneiss&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dgneiss"> <span id="translatedtitle">Manicouagan impact <span class="hlt">melt</span>, Quebec. II - Chemical interrelations with basement and formational processes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The basement rocks of Manicouagan exhibit a wide compositional range (40-72% SiO2). Least squares mixing calculations indicate that the average composition of the Manicouagan <span class="hlt">melt</span> sheet can be modeled for 9 major and 11 trace elements by a mixture of 4.5% anorthosite, 55.5% mafic gneiss, and 40.0% tan gneiss with a granitic-granodioritic composition. The underrepresentation of anorthosite relative to its present distribution is considered. The homogeneous composition of the <span class="hlt">melt</span> (57.75 + or - 1.21% SiO2) relative to that of the <span class="hlt">postulated</span> target is explained in a model outlining the dynamic conditions existing during the formation of the <span class="hlt">melt</span> and its accompanying movement into the excavated cavity.</p> <div class="credits"> <p class="dwt_author">Grieve, R. A. F.; Floran, R. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">265</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60748010"> <span id="translatedtitle">Source term evaluation for <span class="hlt">postulated</span> UFâ release accidents in gaseous diffusion plants -- Summer ventilation mode (non-seismic cases)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Computer models have been developed to simulate the transient behavior of aerosols and vapors as a result of a <span class="hlt">postulated</span> accident involving the release of uranium hexafluoride (UFâ) into the process building of a gaseous diffusion plant. For the current study, gaseous UFâ is assumed to get released in the cell housing atmosphere through B-line break at 58.97 kg\\/s for</p> <div class="credits"> <p class="dwt_author">S. H. Kim; N. C. J. Chen; R. P. Taleyarkhan; M. W. Wendel; K. D. Keith; R. W. Schmidt; J. C. Carter; R. H. Dyer</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">266</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.apsnet.org/edcenter/k-12/teachersguide/brownrot/Pages/default.aspx"> <span id="translatedtitle">Who Done It? Or what's that brown fuzzy stuff on my plum? (Koch's <span class="hlt">Postulates</span> for Proof of Pathogenicity)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This resource demonstrates how plant pathologists and microbiologists determine what pathogens cause disease in plants or animals. In this lab students will learn about Kochs <span class="hlt">Postulates</span>, the critical steps used to prove that a particular microbe is the cause of a specific disease in a host organism (plant or animal). This lesson is suitable for grades 7-12 and does not require the purchase or maintenance of special cultures. A simplified exercise, without cultures, to demonstrate the Germ Theory also is described.</p> <div class="credits"> <p class="dwt_author">Claudia A. Jasalavich (Nashua, NH ;); Gail L. Schumann (University of Massachusetts, Amherst;)</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-11-28</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">267</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=pot&pg=4&id=EJ605986"> <span id="translatedtitle">Beyond the <span class="hlt">Melting</span> Pot Reconsidered.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Discusses the 1963 book, "Beyond the <span class="hlt">Melting</span> Pot," which suggested that eventually the problem of different ethnicities in the U.S. would be resolved and society would become one <span class="hlt">melting</span> pot. Examines how changes in immigration and economic structures have affected the issue, noting the devastating effect of the dominant culture's denigration of…</p> <div class="credits"> <p class="dwt_author">Anderson, Elijah</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">268</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/119875"> <span id="translatedtitle">Ferrocyanide Safety Program: Analysis of <span class="hlt">postulated</span> energetic reactions and resultant aerosol generation in Hanford Site Waste Tanks</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report reviews work done to estimate the possible consequences of <span class="hlt">postulated</span> energetic reactions in ferrocyanide waste stored in underground tanks at the Hanford Site. The issue of explosive reactions was raised in the 1987 Environmental Impact Statement (EIS), where a detonation-like explosion was <span class="hlt">postulated</span> for the purpose of defining an upper bound on dose consequences for various disposal options. A review of the explosion scenario by the General Accounting Office (GAO) indicated that the aerosol generation and consequent radioactive doses projected for the explosion <span class="hlt">postulated</span> in the EIS were understated by one to two orders of magnitude. The US DOE has sponsored an extensive study of the hazard posed by uncontrolled exothermic reactions in ferrocyanide waste, and results obtained during the past three years have allowed this hazard to be more realistically assessed. The objective of this report is to summarize the improved knowledge base that now indicates that explosive or vigorous chemical reactions are not credible in the ferrocyanide waste stored in underground tanks. This improved understanding supports the decision not to proceed with further analyses or predictions of the consequences of such an event or with aerosol tests in support of such predictions. 53 refs., 2 tabs.</p> <div class="credits"> <p class="dwt_author">Postma, A.K. [G and P Consulting, Inc., Dallas, OR (United States); Dickinson, D.R. [Westinghouse Hanford Co., Richland, WA (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">269</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008APS..MARJ40001B"> <span id="translatedtitle">The <span class="hlt">melting</span> curve of MgSiO3 perovskite from ab initio molecular dynamics using the coexistience method</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Despite its importance in understanding such things as the crystallisation of the Earth's mantle from a magma ocean or the existence of <span class="hlt">melt</span> in the current mantle, the <span class="hlt">melting</span> temperature of the lower mantle phase MgSiO3 perovskite is poorly know. Estimates of its <span class="hlt">melting</span> temperature at the <span class="hlt">core</span>-mantle-boundary range from 5400 K to over 8000 K. We have used, therefore, ab initio molecular dynamics simulations to predict its <span class="hlt">melting</span> temperature throughout the Earth's mantle using the coexistence method. We used 900 atoms (a 3x3x5 super-cell) with atoms in one half of the super-cell <span class="hlt">melted</span> and the other half solid. Both halves are thermalised to the desired temperature individually. We then turned off the thermalisation and allowed the system to evolve in an NVE simulation, using DFT forces calculated within the GGA. Those systems which were too hot <span class="hlt">melted</span> within 10 ps. Those which didn't remained with both solid and <span class="hlt">melt</span> coexisting in the super-cell for over 25 ps. These where assumed to be either on the <span class="hlt">melting</span> curve of just below it. Our results agree well with the higher temperature <span class="hlt">melting</span> curves found experimentally, and we predict a <span class="hlt">melting</span> temperature of about 6500 K at the <span class="hlt">core</span>-mantle boundary. We will also present results on simulating the <span class="hlt">melting</span> temperature of the MgO-MgSiO3 binary.</p> <div class="credits"> <p class="dwt_author">Brodholt, John</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">270</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/544173"> <span id="translatedtitle">Ash <span class="hlt">melting</span> treatment by rotating type surface <span class="hlt">melting</span> furnace</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Results of <span class="hlt">melting</span> treatment of fly ash from municipal solid waste incinerators are described, and safety and an effective use of slag discharged from the <span class="hlt">melting</span> treatment are studied. The fly ash has an average particle size of 22 {micro}m and a <span class="hlt">melting</span> fluidity point of 1280--1330 C and was able to be <span class="hlt">melted</span> by using a Kubota <span class="hlt">melting</span> furnace without any additives. Eighty-eight percent of the fly ash was turned to slag and 12% to dust, which contained a lot of heavy metals such as Pb and Zn. Dioxins in the supplied fly ash were 10 ng TEQ/g, originally, and 99.98% was decomposed by the <span class="hlt">melting</span> treatment. Dioxin concentrations of slag, fly ash and flue gas from the <span class="hlt">melting</span> treatment were 0.00, 0.00 and 0.25 ng TEQ/m{sup 3} N, respectively. A leaching test was conducted to confirm the safety of slag. Leaching level of heavy metals from slag was significantly lower than compared to those of bottom and fly ashes from municipal solid waste (MSW) incinerators. It was found that leaching is influenced by pH and the specific surface area of the materials. Furthermore, using slag as a ceramic material, slag was ground and burned at a relatively low temperature (900--1100 C) into a ceramic with strength equal to or more than that of general ceramic tiles.</p> <div class="credits"> <p class="dwt_author">Abe, Seiichi; Kambayashi, Fumiaki; Okada, Masaharu [Kubota Corp., Naniwa, Osaka (Japan). Environmental Plant Div.] [Kubota Corp., Naniwa, Osaka (Japan). Environmental Plant Div.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-12-31</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">271</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JEMat..43.2017Z"> <span id="translatedtitle">Commercial Zone <span class="hlt">Melting</span> Ingots</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Bismuth telluride-based compounds have been extensively utilized for commercial application. However, thermoelectric materials must suffer numerous mechanical vibrations and thermal stresses while in service, making it equally important to discuss the mechanical properties, especially at high temperature. In this study, the compressive and bending strengths of Bi0.5Sb1.5Te3 commercial zone <span class="hlt">melting</span> (ZM) ingots were investigated at 25, 100, and 200 °C, respectively. Due to the obvious anisotropy of materials prepared by ZM method, the effect of anisotropy on the strengths was also explored. Two-parameter Weibull distribution was employed to fit a series of values acquired by a universal testing machine. And digital speckle photography was applied to record the strain field evolution, providing visual observation of surface strain. The compressive and bending strengths along ZM direction were approximately three times as large as those perpendicular to the ZM direction independent of the temperature, indicating a weak van der Waals bond along the c axis.</p> <div class="credits"> <p class="dwt_author">Zheng, Yun; Xie, Hongyao; Shu, Shengcheng; Yan, Yonggao; Li, Han; Tang, Xinfeng</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">272</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60696194"> <span id="translatedtitle">Lower <span class="hlt">core</span> support assembly defueling plans and tools</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Prior to February 1985 it was the accepted technical opinion that little or no fuel <span class="hlt">melting</span> had occurred in the TMI-2 <span class="hlt">core</span> during the accident of March 28, 1979. However, at this time a camera was inserted between the <span class="hlt">core</span> support cylinder and the reactor vessel wall. This camera was inserted into the vessel down to the vicinity of the</p> <div class="credits"> <p class="dwt_author">R. F. Ryan; R. Blumberg</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">273</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE89011030"> <span id="translatedtitle">Lower <span class="hlt">Core</span> Support Assembly Defueling Plans and Tools.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Prior to February 1985 it was the accepted technical opinion that little or no fuel <span class="hlt">melting</span> had occurred in the TMI-2 <span class="hlt">core</span> during the accident of March 28, 1979. However, at this time a camera was inserted between the <span class="hlt">core</span> support cylinder and the reactor...</p> <div class="credits"> <p class="dwt_author">R. Blumberg R. F. Ryan</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">274</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60044785"> <span id="translatedtitle">Disassembly and defueling of the upper <span class="hlt">core</span> support assembly</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">During normal operation of the reactor plant, the upper <span class="hlt">core</span> support assembly (UCSA) holds the fuel assemblies in a defined geometry and establishes the flow path of the reactor coolant in the reactor vessel. Sometime during the course of the Three Mile Island Unit 2 accident, molten <span class="hlt">core</span> material <span class="hlt">melted</span> through a portion of the UCSA and flowed outside the</p> <div class="credits"> <p class="dwt_author">Rodabaugh</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">275</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ANLTRANS1098"> <span id="translatedtitle">System to Reduce the Hazards of a Reactor <span class="hlt">Core</span> Meltdown.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The <span class="hlt">core</span> catcher is realized by the fact that at least on the inner side facing the reactor <span class="hlt">core</span> it consists of at least one high-<span class="hlt">melting</span> material from the group of graphite, carbides and material combinations of graphite fibers and/or filaments with carb...</p> <div class="credits"> <p class="dwt_author">L. Barleon S. Dorner O. Goetzmann G. Kussmaul</p> <p class="dwt_publisher"></p> <p class="publishDate">1977-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">276</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60143330"> <span id="translatedtitle">An assessment of the radiological doses resulting from accidental uranium aerosol releases and fission product releases from a <span class="hlt">postulated</span> criticality accident at the Oak Ridge Y-12 Plant</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A dose assessment for two separate normalized source terms was conducted for the Oak Ridge Y-12 Plant. The first source term consisted of the noble gas and iodine fission products emanating from a <span class="hlt">postulated</span> criticality with a magnitude of 10¹⁹ fissions. The second <span class="hlt">postulated</span> source term was 1 kg of respirable highly enriched uranium. The MELCOR Accident Consequence Code System</p> <div class="credits"> <p class="dwt_author">S. E. Fisher; K. E. Lenox</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">277</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JChEd..86..644S"> <span id="translatedtitle">Thermodynamics of Oligonucleotide Duplex <span class="hlt">Melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Melting</span> temperatures of oligonucleotides are useful for a number of molecular biology applications, such as the polymerase chain reaction (PCR). Although <span class="hlt">melting</span> temperatures are often calculated with simplistic empirical equations, application of thermodynamics provides more accurate <span class="hlt">melting</span> temperatures and an opportunity for students to apply rigorous thermodynamic analysis to an important biochemical problem. Because the stacking of base pairs on top of one another is a significant factor in the energetics of oligonucleotide <span class="hlt">melting</span>, several investigators have applied van't Hoff analysis to <span class="hlt">melting</span> temperature data using a nearest-neighbor model and have obtained entropies and enthalpies for the stacking of bases. The present article explains how the equilibrium constant for the dissociation of strands from double-stranded oligonucleotides can be expressed in terms of the total strand concentration and thus how the total strand concentration influences the <span class="hlt">melting</span> temperature. It also presents a simplified analysis based on the entropies and enthalpies of stacking that is manually tractable so that students can work examples to help them understand the thermodynamics of oligonucleotide <span class="hlt">melting</span>.</p> <div class="credits"> <p class="dwt_author">Schreiber-Gosche, Sherrie; Edwards, Robert A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">278</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/46959583"> <span id="translatedtitle">Mechanism of Disulfide–Disulfide Interchange in Polysulfide Polymer <span class="hlt">Melt</span> Blend by Electron Ionization Mass Spectrometry. II</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The degree of randomization, q, of structural units in <span class="hlt">melt</span> blends of the polysulfide homopolymers A(PS1) and B(PS2), wherein the disulfide equivalents DA\\/DB = 1, were studied by electron ionization mass spectrometry. Over the temperature range of 207–219°C, the relaxation process, due to the dominant disulfide–disulfide interchange reactions, is <span class="hlt">postulated</span> to follow an associative reaction mechanism. These intermolecular disulfide–disulfide interactions promote a</p> <div class="credits"> <p class="dwt_author">Harri G. Ramjit</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">279</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20050175978&hterms=liquid+crystal+pdf&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dliquid%2Bcrystal%2Bpdf"> <span id="translatedtitle">Influence of Silicate <span class="hlt">Melt</span> Composition on Metal/Silicate Partitioning of W, Ge, Ga and Ni</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The depletion of the siderophile elements in the Earth's upper mantle relative to the chondritic meteorites is a geochemical imprint of <span class="hlt">core</span> segregation. Therefore, metal/silicate partition coefficients (Dm/s) for siderophile elements are essential to investigations of <span class="hlt">core</span> formation when used in conjunction with the pattern of elemental abundances in the Earth's mantle. The partitioning of siderophile elements is controlled by temperature, pressure, oxygen fugacity, and by the compositions of the metal and silicate phases. Several recent studies have shown the importance of silicate <span class="hlt">melt</span> composition on the partitioning of siderophile elements between silicate and metallic liquids. It has been demonstrated that many elements display increased solubility in less polymerized (mafic) <span class="hlt">melts</span>. However, the importance of silicate <span class="hlt">melt</span> composition was believed to be minor compared to the influence of oxygen fugacity until studies showed that <span class="hlt">melt</span> composition is an important factor at high pressures and temperatures. It was found that <span class="hlt">melt</span> composition is also important for partitioning of high valency siderophile elements. Atmospheric experiments were conducted, varying only silicate <span class="hlt">melt</span> composition, to assess the importance of silicate <span class="hlt">melt</span> composition for the partitioning of W, Co and Ga and found that the valence of the dissolving species plays an important role in determining the effect of composition on solubility. In this study, we extend the data set to higher pressures and investigate the role of silicate <span class="hlt">melt</span> composition on the partitioning of the siderophile elements W, Ge, Ga and Ni between metallic and silicate liquid.</p> <div class="credits"> <p class="dwt_author">Singletary, S. J.; Domanik, K.; Drake, M. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">280</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007MHD....43..189G"> <span id="translatedtitle">Modeling of the <span class="hlt">melt</span> flow in continuous casting facilities</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the presented paper we describe the results of the experimental study of a liquid metal flow in a low-temperature model of a continuous casting facility equipped with two electromagnetic stirrers (EMS). The characteristics of turbulent <span class="hlt">melt</span> flows in such facilities are computed on the basis of a semi-empirical model of "external" friction taking into account the experimental distribution of angular velocities along the liquid <span class="hlt">core</span> of the ingot. The proposed mathematical model allows us to explain the features of the angular velocities distribution along the liquid <span class="hlt">core</span> of the ingot. Figs 4, Refs 3.</p> <div class="credits"> <p class="dwt_author">Golbraikh, E.; Kapusta, A.; Mikhailovich, B.; Lesin, Sh.; Khavkin, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-06-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">281</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850011815&hterms=hot+melt&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2522hot%2Bmelt%2522"> <span id="translatedtitle">Hot <span class="hlt">melt</span> adhesive attachment pad</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A hot <span class="hlt">melt</span> adhesive attachment pad for releasably securing distinct elements together is described which is particularly useful in the construction industry or a spatial vacuum environment. The attachment pad consists primarily of a cloth selectively impregnated with a charge of hot <span class="hlt">melt</span> adhesive, a thermo-foil heater, and a thermo-cooler. These components are securely mounted in a mounting assembly. In operation, the operator activates the heating cycle transforming the hot <span class="hlt">melt</span> adhesive to a substantially liquid state, positions the pad against the attachment surface, and activates the cooling cycle solidifying the adhesive and forming a strong, releasable bond.</p> <div class="credits"> <p class="dwt_author">Fox, R. L.; Frizzill, A. W.; Little, B. D.; Progar, D. J.; Coultrip, R. H.; Couch, R. H.; Gleason, J. R.; Stein, B. A.; Buckley, J. D.; St.clair, T. L. (inventors)</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">282</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1985JOM....37k..29F"> <span id="translatedtitle">Electrical Conductivity of Cryolite <span class="hlt">Melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper proposes an equation for the electrical conductivity of multicomponent cryolite-based mixtures. The equation is based on a physical model which assumes that the conductivity is proportional to the number density of the effective electric charges in the <span class="hlt">melt</span>. The various authors in the available literature show a great discrepancy in conductivity data of cryolite-based <span class="hlt">melts</span>. The equation based on the physical model enables determination of which set of data is preferable. Special consideration in this respect is given to the influence of magnesium flouride and lithium flouride additions to the <span class="hlt">melt</span>.</p> <div class="credits"> <p class="dwt_author">Fellner, P.; Grjotheim, K.; Kvande, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">283</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/638217"> <span id="translatedtitle">Plasma arc <span class="hlt">melting</span> of zirconium</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Zirconium, like some other refractory metals, has an undesirable sensitivity to interstitials such as oxygen. Traditionally, zirconium is processed by electron beam <span class="hlt">melting</span> to maintain minimum interstitial contamination. Electron beam <span class="hlt">melted</span> zirconium, however, does not respond positively to mechanical processing due to its large grain size. The authors undertook a study to determine if plasma arc <span class="hlt">melting</span> (PAM) technology could be utilized to maintain low interstitial concentrations and improve the response of zirconium to subsequent mechanical processing. The PAM process enabled them to control and maintain low interstitial levels of oxygen and carbon, produce a more favorable grain structure, and with supplementary off-gassing, improve the response to mechanical forming.</p> <div class="credits"> <p class="dwt_author">Tubesing, P.K.; Korzekwa, D.R.; Dunn, P.S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-12-31</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">284</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17734137"> <span id="translatedtitle">Circulation and <span class="hlt">melting</span> beneath the ross ice shelf.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Thermohaline observations in the water column beneath the Ross Ice Shelf and along its terminal face show significant vertical stratification, active horizontal circulation, and net <span class="hlt">melting</span> at the ice shelf base. Heat is supplied by seawater that moves southward beneath the ice shelf from a central warm <span class="hlt">core</span> and from a western region of high salinity. The near-freezing Ice Shelf Water produced flows northward into the Ross Sea. PMID:17734137</p> <div class="credits"> <p class="dwt_author">Jacobs, S S; Gordon, A L; Ardai, J L</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">285</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFMPP23A1080U"> <span id="translatedtitle">Biological Ice <span class="hlt">Core</span> Analysis in Russian Altai</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In July 2003, a 171m long ice <span class="hlt">core</span> was excavated from top of Belukha glacier (4,200m a. s. l.) in the Russian Altai Mountains. We examined vertical distributions of microorganisms (unicellular green algae, fungal spore, yeast) and pollens for potential use of ice <span class="hlt">core</span> dating and reconstruction of past climate. Microorganisms have no seasonal variation in pit samples, however 5 genus of pollen (Fir, Spruce, Pine, Birch tree and Mugwort) have seasonality of each dispersed season. Therefore, this ice <span class="hlt">core</span> can be identified past seasonal layers by pollen distribution. Pollen dating analysis of ice <span class="hlt">core</span> estimate upper 48m ice <span class="hlt">core</span> contain 86 years snow and ice, and this dating method well correspond to the 1963 peak in Tritium. This dating analysis is more accurate than other markers (oxygen isotope, dust, chemical concentration and <span class="hlt">melt</span> percentage). Oxygen isotope trend from 1917 and temperature record of meteorological station near the glacier slightly increased and <span class="hlt">melt</span> percentage have some anomalies from 1950s show recent temperature rising in this region. Otherwise, microorganisms and pollen have no trend except yeast. Vertical distribution of yeast peaks are well correspond to peaks of <span class="hlt">melt</span> percentage show that yeast cell can grow in surface snow only in the warm period when liquid water available. In 1970s and 1980s, Nitrate increased and peaked because of anthropogenic emissions. Nitrate is major nutrient of photosynthetic microorganism, however, no clear relationship nitrate between unicellular green algae.</p> <div class="credits"> <p class="dwt_author">Uetake, J.; Nakazawa, F.; Kohshima, S.; Miyake, T.; Narita, H.; Fujita, K.; Takeuchi, N.; Nakawo, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">286</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..16.4174C"> <span id="translatedtitle"><span class="hlt">Melting</span> granites to make granites</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Large-scale partial <span class="hlt">melting</span> in the continental crust is widely attributed to fluid-absent incongruent breakdown of hydrous minerals in the case of pelites, greywackes and meta-mafic rocks. Granite is a far more common rock in the continental crust, but fluid-absent hydrate-breakdown <span class="hlt">melting</span> is unlikely to result in significant <span class="hlt">melting</span> in granites because of their low modal abundance of mica or amphibole. Experiments show that fluid-present <span class="hlt">melting</span> can produce ~30% <span class="hlt">melt</span> at low temperatures (690°C). Thus, granites and leucogranites can be very fertile if H2O-present <span class="hlt">melting</span> occurs via reactions such as plagioclase + quartz + K-feldspar + H2O = <span class="hlt">melt</span>, because of their high modal proportions of the reactant phases. Our study investigates the Kinawa Migmatite in the São Francisco Craton, southeastern Brazil. This migmatite is derived from an Archaean TTG sequence and can be divided into; 1) pink diatexites, 2) leucosomes, 3) grey gneisses and 4) amphibolites. The migmatite records upper-amphibolite to beginning of granulite facies metamorphism in a P-T range from 5.1-6.6 kbar and ~650-780°C. Pink diatexites are the most abundant rocks, and their appearance varies depending on the amount of <span class="hlt">melt</span> they contained. Three types are recognised: residual diatexites (low <span class="hlt">melt</span> fraction (Mf)), schlieren diatexites (moderate Mf) and homogeneous diatexites (high Mf). They are very closely related spatially in the field, with mostly transitional contacts. There is a sequence with progressive loss of ferromagnesian minerals, schollen and schlieren through the sequence to the most <span class="hlt">melt</span>-rich parts of the diatexites as magmatic flow became more intense. There are fewer ferromagnesian minerals, thus the <span class="hlt">melt</span> becomes cleaner (more leucocratic) and, because the schlieren have disaggregated the aspect is more homogeneous. These parts are texturally similar to leucogranites in which the biotite is randomly distributed and pre-<span class="hlt">melting</span> structures are completely destroyed. The likely protolith for the migmatites was a leucocratic granodiorite (with modal K-feldspar up to 30% and biotite up to 5%), and from geochemical modelling the degree of partial <span class="hlt">melting</span> ranged from 0.21 to 0.25. Furthermore, the residual diatexites show a complementary low modal proportion, or even absence, of K-feldspar, but an increase in modal plagioclase, quartz (up to 56 and 37% respectively) and biotite (5-16%). This suggests that the <span class="hlt">melting</span> reaction did not involve biotite and that plagioclase and quartz were in excess. As result the <span class="hlt">melt</span> generated is fairly leucocratic, and most of the mafic phases in it are inherited. Anatectic <span class="hlt">melts</span> in the Kinawa Migmatite were mildly metaluminous and distinctly leucocratic (A/CNK from 0.97 to 1.01; SiO2 from 72.8 to 75.65%; (FeOT+MgO+TiO2) from 0.49 to 2.3%). Since most granites have a higher (FeOT+MgO+TiO2), additional processes must add the "mafic component" to these <span class="hlt">melts</span> before they form plutons.</p> <div class="credits"> <p class="dwt_author">Carvalho, Bruna B.; Sawyer, Edward W.; Janasi, Valdecir de A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">287</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFM.V13B0662O"> <span id="translatedtitle">Evidence for broad hotspot <span class="hlt">melting</span> anomalies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Mantle plumes are widely portrayed as mushroom-like `head` and thin `tail` structures that rise from a deep thermal boundary layer, generally depicted as the <span class="hlt">core</span>-mantle boundary. This `classic` plume model has been highly successful in explaining age-progressive seamount chains as a reflection of lithospheric plate motion over thin plume `tails`. Much effort has also been spent examining evidence that may link age-progressive seamount chains to Large Igneous Provinces (LIPs), the latter being interpreted as relic plume 'head' structures. However, recent numerical modeling of thermo-chemical plumes indicates that not all plumes have simple `head` and `tail` structures (e.g., Farnetani and Samuel, 2006; Lin and van Keken, 2004, 2006). Plumes may be impinging against the base of the lithosphere in a variety of shapes and sizes, possibly episodically. Similarly, our direct age dating of the Foundation Seamount Chain, SE Pacific, suggests that the narrowness of seamount chains might mask far broader underlying hotspots. Furthermore, our geochronological data show that the Galapagos Volcanic Province (GVP) developed via the progression of broad regions of concurrent dispersed volcanism that we link to a correspondingly broad mantle <span class="hlt">melting</span> anomaly. Evidence from numerical modelling and direct dating of the volcanic record is therefore suggesting that hotspot <span class="hlt">melting</span> anomalies might be much broader than commonly inferred from seamount chains. Thus, the criteria for sampling the volcanic record as a test of the plume hypothesis may require modification. We present a revised approach based on multiple seamount chains that stretch across broad regions of seafloor. These investigations test 1) the new thinking that plumes differ from the classic `head-tail` structure and 2) the inference from recent dating of Pacific seamount chains that hotspot <span class="hlt">melting</span> anomalies are much broader than suggested by the dimensions of individual chains of seamounts and ridges.</p> <div class="credits"> <p class="dwt_author">O'Connor, J. M.; Stoffers, P.; Wijbrans, J. R.; Worthington, T. J.; Jokat, W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">288</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/867989"> <span id="translatedtitle">Nuclear reactor <span class="hlt">melt</span>-retention structure to mitigate direct containment heating</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A light water nuclear reactor <span class="hlt">melt</span>-retention structure to mitigate the extent of direct containment heating of the reactor containment building. The structure includes a retention chamber for retaining molten <span class="hlt">core</span> material away from the upper regions of the reactor containment building when a severe accident causes the bottom of the pressure vessel of the reactor to fail and discharge such molten material under high pressure through the reactor cavity into the retention chamber. In combination with the <span class="hlt">melt</span>-retention chamber there is provided a passageway that includes molten <span class="hlt">core</span> droplet deflector vanes and has gas vent means in its upper surface, which means are operable to deflect molten <span class="hlt">core</span> droplets into the retention chamber while allowing high pressure steam and gases to be vented into the upper regions of the containment building. A plurality of platforms are mounted within the passageway and the <span class="hlt">melt</span>-retention structure to direct the flow of molten <span class="hlt">core</span> material and help retain it within the <span class="hlt">melt</span>-retention chamber. In addition, ribs are mounted at spaced positions on the floor of the <span class="hlt">melt</span>-retention chamber, and grid means are positioned at the entrance side of the retention chamber. The grid means develop gas back pressure that helps separate the molten <span class="hlt">core</span> droplets from discharged high pressure steam and gases, thereby forcing the steam and gases to vent into the upper regions of the reactor containment building.</p> <div class="credits"> <p class="dwt_author">Tutu, Narinder K. (Manorville, NY) [Manorville, NY; Ginsberg, Theodore (East Setauket, NY) [East Setauket, NY; Klages, John R. (Mattituck, NY) [Mattituck, NY</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">289</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PEPI..233...13L"> <span id="translatedtitle">The NiSi <span class="hlt">melting</span> curve to 70 GPa</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">melting</span> curve of NiSi has been determined to 70 GPa on the basis of laser-heated diamond anvil cell (LH-DAC) experiments in which changes in the gradient of temperature vs. laser power functions were used as the <span class="hlt">melting</span> criterion. The <span class="hlt">melting</span> curve was corroborated with in situ X-ray diffraction experiments in both the LH-DAC and multi-anvil press in which the appearance of liquid diffuse scattering in the diffraction patterns was used as the <span class="hlt">melting</span> criterion. At all pressures, the NiSi <span class="hlt">melting</span> curve is lower than that of FeSi, with the difference in <span class="hlt">melting</span> temperature reaching a maximum of 900 K at 14 GPa. The location of the B31 + B20 + L triple point has been constrained to 12 ± 2 GPa and 1550 ± 100 K and the B20 + B2 + L triple point to 28.5 ± 1.5 GPa and 2165 ± 60 K. On the basis of the in situ LH-DAC experiments the Clapeyron slope of the B20 ? B2 transition is estimated at -67 MPa K-1. Extrapolation of the B2-NiSi liquidus to <span class="hlt">core</span>-mantle boundary (CMB) conditions (135 GPa) suggests the <span class="hlt">melting</span> point of NiSi (3700 ± 400 K) will be only marginally lower than that of isostructural FeSi (4000 ± 200 K). Thus any (Fe,Ni)Si solid solution present within the D? layer is expected to remain solid, with the possible exception of the very hottest region adjacent to the CMB.</p> <div class="credits"> <p class="dwt_author">Lord, Oliver T.; Wann, Elizabeth T. H.; Hunt, Simon A.; Walker, Andrew M.; Santangeli, James; Walter, Michael J.; Dobson, David P.; Wood, Ian G.; Vo?adlo, Lidunka; Morard, Guillaume; Mezouar, Mohamed</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">290</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18562280"> <span id="translatedtitle">Evidence for fractional crystallization of wadsleyite and ringwoodite from olivine <span class="hlt">melts</span> in chondrules entrained in shock-<span class="hlt">melt</span> veins.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Peace River is one of the few shocked members of the L-chondrites clan that contains both high-pressure polymorphs of olivine, ringwoodite and wadsleyite, in diverse textures and settings in fragments entrained in shock-<span class="hlt">melt</span> veins. Among these settings are complete olivine porphyritic chondrules. We encountered few squeezed and flattened olivine porphyritic chondrules entrained in shock-<span class="hlt">melt</span> veins of this meteorite with novel textures and composition. The former chemically unzoned (Fa(24-26)) olivine porphyritic crystals are heavily flattened and display a concentric intergrowth with Mg-rich wadsleyite of a very narrow compositional range (Fa(6)-Fa(10)) in the <span class="hlt">core</span>. Wadsleyite <span class="hlt">core</span> is surrounded by a Mg-poor and chemically stark zoned ringwoodite (Fa(28)-Fa(38)) belt. The wadsleyite-ringwoodite interface denotes a compositional gap of up to 32 mol % fayalite. A transmission electron microscopy study of focused ion beam slices in both regions indicates that the wadsleyite <span class="hlt">core</span> and ringwoodite belt consist of granoblastic-like intergrowth of polygonal crystallites of both ringwoodite and wadsleyite, with wadsleyite crystallites dominating in the <span class="hlt">core</span> and ringwoodite crystallites dominating in the belt. Texture and compositions of both high-pressure polymorphs are strongly suggestive of formation by a fractional crystallization of the olivine <span class="hlt">melt</span> of a narrow composition (Fa(24-26)), starting with Mg-rich wadsleyite followed by the Mg-poor ringwoodite from a shock-induced <span class="hlt">melt</span> of olivine composition (Fa(24-26)). Our findings could erase the possibility of the resulting unrealistic time scales of the high-pressure regime reported recently from other shocked L-6 chondrites. PMID:18562280</p> <div class="credits"> <p class="dwt_author">Miyahara, Masaaki; El Goresy, Ahmed; Ohtani, Eiji; Nagase, Toshiro; Nishijima, Masahiko; Vashaei, Zahra; Ferroir, Tristan; Gillet, Philippe; Dubrovinsky, Leonid; Simionovici, Alexandre</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-06-24</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">291</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2438373"> <span id="translatedtitle">Evidence for fractional crystallization of wadsleyite and ringwoodite from olivine <span class="hlt">melts</span> in chondrules entrained in shock-<span class="hlt">melt</span> veins</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Peace River is one of the few shocked members of the L-chondrites clan that contains both high-pressure polymorphs of olivine, ringwoodite and wadsleyite, in diverse textures and settings in fragments entrained in shock-<span class="hlt">melt</span> veins. Among these settings are complete olivine porphyritic chondrules. We encountered few squeezed and flattened olivine porphyritic chondrules entrained in shock-<span class="hlt">melt</span> veins of this meteorite with novel textures and composition. The former chemically unzoned (Fa24–26) olivine porphyritic crystals are heavily flattened and display a concentric intergrowth with Mg-rich wadsleyite of a very narrow compositional range (Fa6–Fa10) in the <span class="hlt">core</span>. Wadsleyite <span class="hlt">core</span> is surrounded by a Mg-poor and chemically stark zoned ringwoodite (Fa28–Fa38) belt. The wadsleyite–ringwoodite interface denotes a compositional gap of up to 32 mol % fayalite. A transmission electron microscopy study of focused ion beam slices in both regions indicates that the wadsleyite <span class="hlt">core</span> and ringwoodite belt consist of granoblastic-like intergrowth of polygonal crystallites of both ringwoodite and wadsleyite, with wadsleyite crystallites dominating in the <span class="hlt">core</span> and ringwoodite crystallites dominating in the belt. Texture and compositions of both high-pressure polymorphs are strongly suggestive of formation by a fractional crystallization of the olivine <span class="hlt">melt</span> of a narrow composition (Fa24–26), starting with Mg-rich wadsleyite followed by the Mg-poor ringwoodite from a shock-induced <span class="hlt">melt</span> of olivine composition (Fa24–26). Our findings could erase the possibility of the resulting unrealistic time scales of the high-pressure regime reported recently from other shocked L-6 chondrites.</p> <div class="credits"> <p class="dwt_author">Miyahara, Masaaki; El Goresy, Ahmed; Ohtani, Eiji; Nagase, Toshiro; Nishijima, Masahiko; Vashaei, Zahra; Ferroir, Tristan; Gillet, Philippe; Dubrovinsky, Leonid; Simionovici, Alexandre</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">292</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N8334044"> <span id="translatedtitle">Hot <span class="hlt">Melt</span> Adhesive Attachment Pad.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The invention relates to a hot <span class="hlt">melt</span> adhesive attachment pad for releasably securing distinct elements together and particularly useful in the construction industry or a spatial vacuum environment. The attachment pad consists primarily of a cloth selective...</p> <div class="credits"> <p class="dwt_author">R. L. Fox A. W. Frizzill B. D. Little D. J. Progar R. H. Coultrip</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">293</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA333393"> <span id="translatedtitle">Borate Glasses, Crystals and <span class="hlt">Melts</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The Final Proceedings for Borate, Glasses, Crystals and <span class="hlt">Melts</span>, 22 July 1996 - 25 July 1996. This is an interdisciplinary conference. Topics include glass forming systems, triborate systems, structural studies, modeling and computer simulation, super-ionic...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">294</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1985JOM....37c..59M"> <span id="translatedtitle">Desulphurization of Steel During <span class="hlt">Melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper examines the extent of sulphur removal from scrap metal charges when gases, which are oxidizing or reducing with respect to iron oxide at unit activity, are blown on to the charge. Sulphur can be removed extensively as gaseous species in the exhaust gas before <span class="hlt">melting</span> is complete. The presence of ferrous oxide, introduced in solid form, and use of the above gas mixtures facilitates sulfur removal to very low levels during the <span class="hlt">melting</span> period and in the absence of flux additions. A stable and low level of sulphur could be maintained at about the clear <span class="hlt">melt</span> stage in the absence of slag or without any further treatment. The optimum operating conditions have been ascertained for desulphurization of steel during <span class="hlt">melting</span>.</p> <div class="credits"> <p class="dwt_author">Motlagh, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">295</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE93005557"> <span id="translatedtitle">Generalized <span class="hlt">melting</span> criterion for amorphization.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">We present a thermodynamic model of solid-state amorphization based on a generalization of the well-known Lindemann criterion. The original Lindemann criterion proposes that <span class="hlt">melting</span> occurs when the root-mean-square amplitude of thermal displacement exceed...</p> <div class="credits"> <p class="dwt_author">R. Devanathan N. Q. Lam P. R. Okamoto M. Meshii</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">296</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5277900"> <span id="translatedtitle">Environmental consequences of <span class="hlt">postulated</span> plutonium releases from Exxon Nuclear MOFP, Richland, Washington, as a result of severe natural phenomena</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Potential environmental consequences in terms of radiation dose to people are presented for <span class="hlt">postulated</span> plutonium releases caused by severe natural phenomena at the Exxon Nuclear Company Mixed Oxide Fabrication Plant (MOFP), Richland, Washington. The severe natural phenomena considered are earthquakes, tornadoes, high straight-line winds, and floods. Maximum plutonium deposition values are given for significant locations around the site. All important potential exposure pathways are examined. The most likely 50-year committed dose equivalents are given for the maximum-exposed individual and the population within a 50-mile radius of the plant. The maximum plutonium deposition values most likely to occur offsite are also given.</p> <div class="credits"> <p class="dwt_author">Jamison, J.D.; Watson, E.C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">297</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.apsnet.org/edcenter/K-12/TeachersGuide/BrownRot/Pages/default.aspx"> <span id="translatedtitle">Who Done It? Or what's that brown fuzzy stuff on my plum?: Koch's <span class="hlt">Postulates</span> for Proof of Pathogenicity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this lab, learners explore Koch's <span class="hlt">Postulates</span>, the critical step used to prove that a particular microbe is the cause of a specific disease in a host organism (plant or animal). This is accomplished by examining the brown fuzzy stuff (a fungal pathogen) growing on a plum and experimentally showing, step by step, whether or not it is the cause of the observed disease. This lesson guide includes background information, instructions for leading a simplified (less time intensive) demonstration of the Germ Theory, study questions and answers, suggestions for additional experiments, and supplemental information and references. Adult supervision recommended.</p> <div class="credits"> <p class="dwt_author">Jasalavich, Claudia A.; Schumann, Gail L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">298</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008GeCoA..72.4756C"> <span id="translatedtitle">Olivine dissolution in basaltic <span class="hlt">melt</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The main purpose of this work is to understand and quantify diffusive and convective olivine dissolution in basaltic <span class="hlt">melt</span>. Crystal dissolution and growth in a magma chamber is often accompanied by the descent or ascent of the crystal in the chamber due to gravity. The motion induces convection that enhances mass transport. Such convective dissolution and growth rates have not been quantified before. MgO diffusivity in the <span class="hlt">melt</span> ( DMgO), MgO concentration of the interface <span class="hlt">melt</span> ( C0) and the effective thickness of the compositional boundary layer (?) are necessary parameters to model the convective dissolution. Experiments of non-convective olivine dissolution in a basaltic <span class="hlt">melt</span> were conducted at 1271-1480 °C and 0.47-1.42 GPa in a piston-cylinder apparatus. At specific temperature and pressure conditions, multiple experiments of different durations show that the interface <span class="hlt">melt</span> reaches near-saturation within 2 min. Therefore, diffusion, not interface reaction, is the rate-controlling step for non-convective olivine dissolution in basaltic <span class="hlt">melt</span>. The compositional profile length and olivine dissolution distance are proportional to the square root of experimental duration, consistent with diffusive dissolution. DMgO and C0 are obtained from the experimental results. DMgO displays Arrhenian dependence on temperature, but the pressure dependence is small and not resolved. C0 increases with increasing temperature and decreases with increasing pressure. Comparison with literature data shows that DMgO depends strongly on the initial <span class="hlt">melt</span> composition, while C0 does not. ? is estimated from fluid dynamics. DMgO/?, which characterizes the kinetic and dynamic aspects of convective crystal dissolution, is parameterized as a function of temperature, pressure, and olivine composition. Convective olivine dissolution rate in basaltic <span class="hlt">melt</span> can be conveniently calculated from the model results. Application to convective crystal growth and xenolith digestion is discussed.</p> <div class="credits"> <p class="dwt_author">Chen, Yang; Zhang, Youxue</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">299</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60290654"> <span id="translatedtitle">Glass <span class="hlt">melting</span> furnace and process</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In Leone International Sales Corp.'s new glass-<span class="hlt">melting</span> furnace, heat transfer from the burning fuel to the <span class="hlt">melting</span> glass is substantially increased by precisely adjusting the position of the burners to substantially reduce the excess-air requirement while maintaining an acceptable carbon monoxide level (35 to 50 ppM) in the flue gases, and to maximize flame coverage of the raw batch material</p> <div class="credits"> <p class="dwt_author">J. D. Nesbitt; D. H. Larson; M. E. Fejer</p> <p class="dwt_publisher"></p> <p class="publishDate">1974-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFM.V12B..02A"> <span id="translatedtitle">Extensive partial <span class="hlt">melting</span> and <span class="hlt">melt</span> extraction in pelitic metasediments: An example from the Chiwaukum schist (Washington Cascades)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Partial <span class="hlt">melting</span> of crustal sediments plays an important role in both the production of anatectic granites (eg. Brown, 1994; Harris et al., 1995; Johnson et al., 2003), and modification of mantle derived <span class="hlt">melts</span> via assimiation (eg. McBirney et al., 1987; Grove et al., 1982). These processes rely heavily on segregation of anatectic <span class="hlt">melts</span> from their sedimentary source (Brown, 1994; Sawyer, 1994; Brown et al., 1995). Here, we investigate the extent of <span class="hlt">melting</span> and <span class="hlt">melt</span> extraction in the pelitic Chiwaukum schist (central Washington St.), within the contact aureole of the Big Jim intrusive complex. The Big Jim complex, part of the regionally extensive Mt. Stuart Batholith, intruded the pelitic Chiwaukum schist at ~96 Ma (Tabor et al., 1982, 1987; Matzel, 2004). It is concentrically zoned, with an ultramafic <span class="hlt">core</span> and intermediate to felsic rim (Kelemen & Ghiorso, 1986). Peak metamorphic grades in the schist reach pyroxene hornfels, and textures indicative of partial <span class="hlt">melting</span> of the schist are apparent; the pelitic schists, and their migmatized counterparts form a continuum from un-migmatized metasediments to structureless, biotite free hornfels, containing leucosome lenses. With increasing grade, there is a continuous decrease in Th and light REE's, elements that are mobile in <span class="hlt">melts</span> and are largely immobile in hydrothermal fluids; REE and trace element patterns show no evidence of contamination of the partially molten schist by the intruding pluton. There is a sharp decrease in K2O in the schist with increasing grade, which correlates with the breakdown of biotite, while there is a sharp concomitant increase in CaO content. By assuming that CaO is immobile, minimum <span class="hlt">melt</span> losses are estimated to be between 0 and 80%. Samples that have experienced greater <span class="hlt">melt</span> loss are characterized by a decrease in Th, K#, and alumina saturation index, while they show increased Ca# and Mg#. This probably results from removal of a peraluminuos, K rich <span class="hlt">melt</span>, with Na2O>>CaO and FeO>MgO, consistent with experimental <span class="hlt">melt</span> compositions from the literature (eg. Vielzeuf and Holloway, 1988; Grant, 2004). Anorthite content of plagioclase increases from An20-An35 in the metasediments to >An90 in the highest grade rocks, consistent with the hypothesis that Ca is largely retained in the residue. Notably, regardless of the estimated degree of <span class="hlt">melt</span> loss, residues retain major and trace element characteristics typical of their metapelitic protolith. The principle <span class="hlt">melting</span> reactions are related to the breakdown of biotite. Plagioclase persists to all grades, while sillimanite is not present in the highest grade rocks, closest to the intrusion contact. Persistence of plagiolcase, and early loss of alumino-silicates may be a result of changing bulk composition due to removal of a <span class="hlt">melt</span> with the afore mentioned characteristics. These results indicate that significant degrees of <span class="hlt">melting</span> and <span class="hlt">melt</span> extraction occur in pelitic metasediments, and have implications for the formation of anatectic granites, and for assimilation in mantle derived basalts as they transit the crust.</p> <div class="credits"> <p class="dwt_author">Austin, N.; Kelemen, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" 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showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_17");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">301</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1996CoMP..125...16S"> <span id="translatedtitle">Dehydration <span class="hlt">melting</span> of tonalites. Part I. Beginning of <span class="hlt">melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The beginning of dehydration <span class="hlt">melting</span> in the tonalite system (biotite-plagioclase-quartz) is investigated in the pressure range of 2 12 kbar. A special method consisting of surrounding a crystal of natural plagioclase (An45) with a biotite-quartz mixture, and observing reactions at the plagioclase margin was employed for precise determination of the solidus for dehydration <span class="hlt">melting</span>. The beginning of dehydration <span class="hlt">melting</span> was worked out at 5 kbar for a range of compositions of biotite varying from iron-free phlogopite to iron-rich Ann70, with and without titanium, fluorine and extra aluminium in the biotite. The dehydration <span class="hlt">melting</span> of phlogopite + plagioclase (An45) + quartz begins between 750 and 770°C at pressures of 2 and 5 kbar, at approximately 740°C at 8 kbar and between 700 and 730°C at 10 kbar. At 12 kbar, the first <span class="hlt">melts</span> are observed at temperatures as low as 700°C. The data indicate an almost vertical dehydration <span class="hlt">melting</span> solidus curve at low pressures which bends backward to lower temperatures at higher pressures (> 5 kbar). The new phases observed at pressures ? 10 kbar are <span class="hlt">melt</span> + enstatite + clinopyroxene + potassium feldspar ± amphibole. In addition to these, zoisite was also observed at 12 kbar. With increasing temperature, phlogopite becomes enriched in aluminium and deficient in potassium. Substitution of octahedral magnesium by aluminium and titanium in the phlogopite, as well as substitution of hydroxyl by fluorine, have little effect on the beginning of dehydration <span class="hlt">melting</span> temperatures in this system. The dehydration <span class="hlt">melting</span> of biotite (Ann50) + plagioclase (An45) + quartz begins 50°C below that of phlogopite bearing starting composition. Solid reaction products are orthopyroxene + clinopyroxene + potassium feldspar ± amphibole. Epidote was also observed above 8 kbar, and garnet at 12 kbar (750°C). The experiments on the iron-bearing system performed at ? 5 kbar were buffered with NiNiO. The f O 2 in high pressure runs lies close to CoCoO. With the substitution of octahedral magnesium and iron by aluminium and titanium, and replacement of hydroxyl by fluorine in biotite, the beginning of dehydration <span class="hlt">melting</span> temperatures in this system increase up to 780°C at 5 kbar, which is 70°C above the beginning of dehydration <span class="hlt">melting</span> of the assemblage containing biotite (Ann50) of ideal composition. The dehydration <span class="hlt">melting</span> at 5 kbar in the more iron-rich Ann70-bearing starting composition begins at 730°C, and in the Ann25-bearing assemblage at 710°C. This indicates that quartz-biotite-plagioclase assemblages with intermediate compositions of biotite (Ann25 and Ann50) <span class="hlt">melt</span> at lower temperatures as compared to those containing Fe-richer or Mg-richer biotites. This study shows that the dehydration <span class="hlt">melting</span> of tonalites may begin at considerably lower temperatures than previously thought, especially at high pressures (>5 kbar).</p> <div class="credits"> <p class="dwt_author">Singh, J.; Johannes, Wilhelm</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JNuM..385..443U"> <span id="translatedtitle">Laser <span class="hlt">melting</span> of uranium carbides</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the context of the material research aimed at supporting the development of nuclear plants of the fourth Generation, renewed interest has recently arisen in carbide fuels. A profound understanding of the behaviour of nuclear materials in extreme conditions is of prime importance for the analysis of the operation limits of nuclear fuels, and prediction of possible nuclear reactor accidents. In this context, the main goal of the present paper is to demonstrate the feasibility of laser induced <span class="hlt">melting</span> experiments on stoichiometric uranium carbides; UC, UC 1.5 and UC 2. Measurements were performed, at temperatures around 3000 K, under a few bars of inert gas in order to minimise vaporisation and oxidation effects, which may occur at these temperatures. Moreover, a recently developed investigation method has been employed, based on in situ analysis of the sample surface reflectivity evolution during <span class="hlt">melting</span>. Current results, 2781 K for the <span class="hlt">melting</span> point of UC, 2665 K for the solidus and 2681 K for the liquidus of U 2C 3, 2754 K for the solidus and 2770 K for the liquidus of UC 2, are in fair agreement with early publications where the <span class="hlt">melting</span> behaviour of uranium carbides was investigated by traditional furnace <span class="hlt">melting</span> methods. Further information has been obtained in the current research about the non-congruent (solidus-liquidus) <span class="hlt">melting</span> of certain carbides, which suggest that a solidus-liquidus scheme is followed by higher ratio carbides, possibly even for UC 2.</p> <div class="credits"> <p class="dwt_author">Utton, C. A.; De Bruycker, F.; Boboridis, K.; Jardin, R.; Noel, H.; Guéneau, C.; Manara, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">303</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFM.C23A0580W"> <span id="translatedtitle">Modeling energy balance and <span class="hlt">melt</span> layer formation on the Kahiltna Glacier, Alaska</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Understanding <span class="hlt">melt</span> on alpine glaciers is required both for accurate mass balance modeling and ice <span class="hlt">core</span> paleoclimate reconstruction. In alpine regions with complex meteorology and topography, modeling <span class="hlt">melt</span> through the quantification and balance of all identifiable energy fluxes is the most complete way of describing how local meteorology influences <span class="hlt">melt</span> layer formation and snowpack evolution. To meet this goal at our field site on the Kahiltna glacier, located in the Central Alaska Range, Denali National Park, we have developed an energy balance model from two years of meteorological data from Kahiltna Base Camp (2100 m elevation, 63.25 degrees N, 151 degrees W). Current model results show the dominance of turbulent heat transfer at the study site and the importance of surface roughness and albedo in controlling <span class="hlt">melt</span>. Preliminary data show a 30 percent overestimation of <span class="hlt">melt</span> flux from the surface into the snowpack although an albedo submodel is being developed which may address this. Sampling of the snowpack across the glacier for analysis of stratigraphic and chemical evolution shows an isothermal near surface snowpack (to at least 1m) at 2100 meters in elevation in the early <span class="hlt">melt</span> season with increasing density and <span class="hlt">melt</span> layer abundance as the summer progresses. This suggests that a large amount of the meltwater remains in the snowpack after surface <span class="hlt">melting</span>. We will discuss further the model’s accuracy in relation to ablation stake measurements as well as the major environmental controls on physical and chemical snowpack evolution into the <span class="hlt">melt</span> season as additional results are processed.</p> <div class="credits"> <p class="dwt_author">Winski, D. A.; Kreutz, K. J.; Osterberg, E. C.; Campbell, S. W.; Denali Ice Core Team</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">304</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..15.2447K"> <span id="translatedtitle">Frictional <span class="hlt">melting</span> and stick-slip behavior in volcanic conduits</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Dome-building eruptions have catastrophic potential, with dome collapse leading to devastating pyroclastic flows with almost no precursory warning. During dome growth, the driving forces of the buoyant magma may be superseded by controls along conduit margins; where brittle fracture and sliding can lead to formation of lubricating cataclasite and gouge. Under extreme friction, pseudotachylyte may form at the conduit margin. Understanding the conduit margin processes is vital to understanding the continuation of an eruption and we <span class="hlt">postulate</span> that pseudotachylyte generation could be the underlying cause of stick-slip motion and associated seismic "drumbeats", which are so commonly observed at dome-building volcanoes. This view is supported by field evidence in the form of pseudotachylytes identified in lava dome products at Soufrière Hills (Montserrat) and Mount St. Helens (USA). Both eruptions were characterised by repetitive, periodic seismicity and lava spine extrusion of highly viscous magma. High velocity rotary shear (HVR) experiments demonstrate the propensity for <span class="hlt">melting</span> of the andesitic and dacitic material (from Soufrière Hills and Mount St. Helens respectively) at upper conduit stress conditions (<10 MPa). Starting from room temperature, frictional <span class="hlt">melting</span> of the magmas occurs in under 1 s (<< 1 m) at 1.5 m/s (a speed that is achievable during stick-slip motion). At lower velocities <span class="hlt">melting</span> occurs comparatively later due to dissipation of heat from the slip zone (e.g. 8-15 m at 0.1 m/s). Hence, given the ease with which <span class="hlt">melting</span> is achieved in volcanic rocks, and considering the high ambient temperatures in volcanic conduits, frictional <span class="hlt">melting</span> may thus be an inevitable consequence of viscous magma ascent. The shear resistance of the slip zone during the experiment is also monitored. Frictional <span class="hlt">melting</span> induces a higher resistance to sliding than rock on rock, and viscous processes control the slip zone properties. Variable-rate HVR experiments which mimic rapid velocity fluctuations in stick-slip behavior demonstrate velocity-weakening behavior of <span class="hlt">melt</span>, with a tendency for unstable slip. During ascent, magma may slip and undergo <span class="hlt">melting</span> along the conduit margin. In the process the shear resistance of the slip zone is increased, acting as a viscous brake halting slip (the "stick" of stick-slip motion). Sufficient buoyancy-driven pressures from ascending magma below eventually overcome resistance to produce a rapid slip event (the "slip") along the <span class="hlt">melt</span>-bearing slip zone, which is temporarily lubricated due to velocity-weakening. New magma below experiences the same slip event more slowly (as the magma decompresses) to produce a viscous brake and the process is repeated. This allows a fixed spatial locus that explains the repetitive drumbeat seismicity and the occurrence of "families" of similar seismic events. We conclude that stick-slip motion in volcanic conduits is a self-driving, frictional-<span class="hlt">melt</span>-regulated force common to many dome building volcanoes.</p> <div class="credits"> <p class="dwt_author">Kendrick, Jackie Evan; Lavallee, Yan; Hirose, Takehiro; di Toro, Giulio; Hornby, Adrian Jakob; Hess, Kai-Uwe; Dingwell, Donald Bruce</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">305</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26598094"> <span id="translatedtitle">Fracture mechanics investigation regarding the effects of cracks on the structural integrity of a BWR-<span class="hlt">core</span> shroud</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">As a consequence of <span class="hlt">core</span> shroud intergranular stress corrosion cracking (IGSCC) detected in the course of inservice inspections, a fracture mechanics analysis was carried out to evaluate the effects of <span class="hlt">postulated</span> cracks on the structural integrity. In this study, critical crack sizes and crack growth were calculated. Due to the comparatively low stress acting on the <span class="hlt">core</span> shroud during normal</p> <div class="credits"> <p class="dwt_author">D Beukelmann; J Schäfer; W Lehmann</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19930061592&hterms=PCT&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPCT"> <span id="translatedtitle">Explosive volcanism and the compositions of <span class="hlt">cores</span> of differentiated asteroids</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Eleven iron meteorite groups show correlations between Ni and siderophile trace elements that are predictable by distribution coefficients between liquid and solid metal in fractionally crystallizing metal magmas. These meteorites are interpreted to be fragments of the fractionally crystallized <span class="hlt">cores</span> of eleven differentiated asteroids. Many of these groups crystallized from S-depleted magmas which we propose resulted from removal of the first partial <span class="hlt">melt</span> (the Fe,Ni-FeS cotectic <span class="hlt">melt</span>) by explosive pyroclastic volcanism of the type envisaged by Wilson and Keil (1991). We show that these dense, negatively buoyant <span class="hlt">melts</span> can be driven to asteroidal surfaces due to the presence of excess pressure in the <span class="hlt">melt</span> and the presence of buoyant bubbles of gas which decrease the density of the <span class="hlt">melt</span>. We also show that, in typical asteroidal materials, veins will form which grow into dikes and serve as pathways for migration of <span class="hlt">melt</span> and gas to asteroidal surfaces. Since cotectic Fe, Ni-FeS <span class="hlt">melt</span> consists of about 85 wt pct FeS and 15 wt pct Fe, Ni, removal of small volumes of eutectic <span class="hlt">melts</span> results in major loss of S but only minor loss of Fe,Ni, thus leaving sufficient Fe,Ni to form sizeable asteroidal <span class="hlt">cores</span>.</p> <div class="credits"> <p class="dwt_author">Keil, Klaus; Wilson, Lionel</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">307</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1993E%26PSL.117..111K"> <span id="translatedtitle">Explosive volcanism and the compositions of <span class="hlt">cores</span> of differentiated asteroids</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Eleven iron meteorite groups show correlations between Ni and siderophile trace elements that are predictable by distribution coefficients between liquid and solid metal in fractionally crystallizing metal magmas. These meteorites are interpreted to be fragments of the fractionally crystallized <span class="hlt">cores</span> of eleven differentiated asteroids. Many of these groups crystallized from S-depleted magmas which we propose resulted from removal of the first partial <span class="hlt">melt</span> (the Fe,Ni-FeS cotectic <span class="hlt">melt</span>) by explosive pyroclastic volcanism of the type envisaged by Wilson and Keil (1991). We show that these dense, negatively buoyant <span class="hlt">melts</span> can be driven to asteroidal surfaces due to the presence of excess pressure in the <span class="hlt">melt</span> and the presence of buoyant bubbles of gas which decrease the density of the <span class="hlt">melt</span>. We also show that, in typical asteroidal materials, veins will form which grow into dikes and serve as pathways for migration of <span class="hlt">melt</span> and gas to asteroidal surfaces. Since cotectic Fe, Ni-FeS <span class="hlt">melt</span> consists of about 85 wt pct FeS and 15 wt pct Fe, Ni, removal of small volumes of eutectic <span class="hlt">melts</span> results in major loss of S but only minor loss of Fe,Ni, thus leaving sufficient Fe,Ni to form sizeable asteroidal <span class="hlt">cores</span>.</p> <div class="credits"> <p class="dwt_author">Keil, K.; Wilson, L.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=https://nationalethicscenter.org/"> <span id="translatedtitle">Ethics <span class="hlt">CORE</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">The Ethics <span class="hlt">CORE</span> Digital Library, funded by the National Science Foundation, "brings together information on best practices in research, ethics instruction and responding to ethical problems that arise in research and professional life." It's a remarkable site where visitors can make their way through ethics resources for dozens of different professions and activities. The Resources by Discipline area is a great place to start. Here you will find materials related to the biological sciences, business, computer & information science, along with 14 additional disciplines. The Current News area is a great place to learn about the latest updates from the field. Of note, these pieces can easily be used in the classroom or shared with colleagues. The dynamism of the site can be found at the Interact with Ethics <span class="hlt">CORE</span> area. Active learning exercises can be found here, along with instructional materials and visitors' own lessons learned.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">309</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..15.7911D"> <span id="translatedtitle">Coupled dynamics of the Earth's inner <span class="hlt">core</span> and F-layer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The hemispherical asymmetry seen in the seismological properties of the inner <span class="hlt">core</span> has recently been interpreted as resulting form a high-viscosity mode of inner <span class="hlt">core</span> thermal convection, consisting in a translation of the inner <span class="hlt">core</span> with <span class="hlt">melting</span> on one hemisphere and solidification on the other. The large <span class="hlt">melt</span> production associated with inner <span class="hlt">core</span> translation may be at the origin of the F-layer, an anomalous, stably stratified layer at the base of the outer <span class="hlt">core</span>, with <span class="hlt">melting</span> of the inner <span class="hlt">core</span> providing the dense iron-rich <span class="hlt">melt</span> necessary for the formation of the layer. Being a thermal convection mode, a prerequisite for the existence of convective translation is that a superadiabatic temperature profile is maintained within the inner <span class="hlt">core</span>, which depends on a competition between extraction of the inner <span class="hlt">core</span> internal heat by conduction and cooling at the ICB. While the low thermal conductivity value proposed by Stacey & Loper (2007) makes inner <span class="hlt">core</span> thermal convection likely, the much higher estimate recently put forward by Sha & Cohen (2011), de Koker et al. (2012) and Pozzo et al. (2012) makes inner <span class="hlt">core</span> thermal convection almost impossible. We argue however that the formation of the F-layer has a positive feedback on inner <span class="hlt">core</span> convection which could overcome the stabilizing effect of a large thermal conductivity. The formation of an iron-rich layer above the ICB implies that the inner <span class="hlt">core</span> crystallizes from a source which is increasingly depleted in light elements. This produces an unstable compositional profile in the inner <span class="hlt">core</span> that intensify inner <span class="hlt">core</span> convection. The reciprocal coupling between the inner <span class="hlt">core</span> and the F-layer creates a positive feedback loop which can make the system (inner <span class="hlt">core</span> + F-layer) unstable. The mechanism releases more gravitational energy than purely radial inner <span class="hlt">core</span> growth with no <span class="hlt">melting</span>, and is therefore energetically favored.</p> <div class="credits"> <p class="dwt_author">Deguen, Renaud; Alboussière, Thierry; Cardin, Philippe</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005GeCoA..69.4733C"> <span id="translatedtitle">Compositions of group IVB iron meteorites and their parent <span class="hlt">melt</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The concentrations of P, V, Cr, Fe, Co, Ni, Cu, Ga, Ge, As, Mo, Ru, Rh, Pd, W, Re, Os, Ir, Pt, and Au in the group IVB iron meteorites Cape of Good Hope, Hoba, Skookum, Santa Clara, Tawallah Valley, Tlacotepec, and Warburton Range have been measured by laser ablation inductively coupled plasma mass spectrometry. The data were fitted to a model of fractional crystallization of the IVB parent body <span class="hlt">core</span>, from which the composition of the parent <span class="hlt">melt</span> and metal/<span class="hlt">melt</span> distribution coefficients for each element in the system were determined, for a chosen value of D(Ni). Relative to Ni and chondritic abundances, the parent <span class="hlt">melt</span> was enriched in refractory siderophiles, with greatest enrichment of 5× chondritic in the most refractory elements, and was strongly volatile-depleted, down to 0.00014× chondritic in Ge. Comparison to an equilibrium condensation sequence from a gas of solar composition indicates that no single temperature satisfactorily explains the volatility trend in the IVB parent <span class="hlt">melt</span>; a small (<1%) complement of ultrarefractory components added to metal that is volatile-depleted but otherwise has nearly chondritic abundances (for Fe, Co and Ni) best explains the volatility trend. In addition to this volatility processing, which probably occurred in a nebular setting, there was substantial oxidation of the metal in the IVB parent body, leading to loss of Fe and other moderately siderophile elements such as Cr, Ga, and W, and producing the high Ni contents that are observed in the IVB irons. By assuming that the entire IVB parent body underwent a similar chemical history as its <span class="hlt">core</span>, the composition of the silicate that is complementary to the IVB parent <span class="hlt">melt</span> was also estimated, and appears to be similar to that of the angrite parent.</p> <div class="credits"> <p class="dwt_author">Campbell, Andrew J.; Humayun, Munir</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4050608"> <span id="translatedtitle">Climate change and forest fires synergistically drive widespread <span class="hlt">melt</span> events of the Greenland Ice Sheet</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">In July 2012, over 97% of the Greenland Ice Sheet experienced surface <span class="hlt">melt</span>, the first widespread <span class="hlt">melt</span> during the era of satellite remote sensing. Analysis of six Greenland shallow firn <span class="hlt">cores</span> from the dry snow region confirms that the most recent prior widespread <span class="hlt">melt</span> occurred in 1889. A firn <span class="hlt">core</span> from the center of the ice sheet demonstrated that exceptionally warm temperatures combined with black carbon sediments from Northern Hemisphere forest fires reduced albedo below a critical threshold in the dry snow region, and caused the <span class="hlt">melting</span> events in both 1889 and 2012. We use these data to project the frequency of widespread <span class="hlt">melt</span> into the year 2100. Since Arctic temperatures and the frequency of forest fires are both expected to rise with climate change, our results suggest that widespread <span class="hlt">melt</span> events on the Greenland Ice Sheet may begin to occur almost annually by the end of century. These events are likely to alter the surface mass balance of the ice sheet, leaving the surface susceptible to further <span class="hlt">melting</span>.</p> <div class="credits"> <p class="dwt_author">Keegan, Kaitlin M.; Albert, Mary R.; McConnell, Joseph R.; Baker, Ian</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24843158"> <span id="translatedtitle">Climate change and forest fires synergistically drive widespread <span class="hlt">melt</span> events of the Greenland Ice Sheet.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">In July 2012, over 97% of the Greenland Ice Sheet experienced surface <span class="hlt">melt</span>, the first widespread <span class="hlt">melt</span> during the era of satellite remote sensing. Analysis of six Greenland shallow firn <span class="hlt">cores</span> from the dry snow region confirms that the most recent prior widespread <span class="hlt">melt</span> occurred in 1889. A firn <span class="hlt">core</span> from the center of the ice sheet demonstrated that exceptionally warm temperatures combined with black carbon sediments from Northern Hemisphere forest fires reduced albedo below a critical threshold in the dry snow region, and caused the <span class="hlt">melting</span> events in both 1889 and 2012. We use these data to project the frequency of widespread <span class="hlt">melt</span> into the year 2100. Since Arctic temperatures and the frequency of forest fires are both expected to rise with climate change, our results suggest that widespread <span class="hlt">melt</span> events on the Greenland Ice Sheet may begin to occur almost annually by the end of century. These events are likely to alter the surface mass balance of the ice sheet, leaving the surface susceptible to further <span class="hlt">melting</span>. PMID:24843158</p> <div class="credits"> <p class="dwt_author">Keegan, Kaitlin M; Albert, Mary R; McConnell, Joseph R; Baker, Ian</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/57626729"> <span id="translatedtitle">Thermal properties of Three Mile Island Unit 2 <span class="hlt">core</span> debris and simulated debris</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Thermal properties of molten and mixed <span class="hlt">core</span> materials are required to be known for effective analysis of <span class="hlt">core</span> damage in severe accidents at nuclear power plants. The specific heat capacity, thermal expansion coefficient, thermal diffusivity, and <span class="hlt">melting</span> temperature were measured or estimated on the <span class="hlt">core</span> debris samples of the Three Mile Island Unit 2 (TMI-2) reactor and simulated debris (SIMDEBRIS),</p> <div class="credits"> <p class="dwt_author">Fumihisa Nagase; Hiroshi Uetsuka</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">314</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFM.V13B2033B"> <span id="translatedtitle">Cracks preserve kimberlite <span class="hlt">melt</span> composition</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The chemical composition of kimberlite <span class="hlt">melts</span> has previously been estimated by measuring aphanitic intrusive rocks (deposit composition) or by partial <span class="hlt">melting</span> experiments on carbonated lherzolites (source composition). Pervasively altered, degassed and contaminated material preclude the determination of the primitive <span class="hlt">melt</span> composition. Here we present data on <span class="hlt">melt</span> compositions trapped in unaltered olivine cracks that have been healed and overgrown prior to shallow level emplacement. During the ascent of kimberlite magma the prograding crack tip samples mantle peridotite xenoliths. Xenoliths rapidly disaggregate over the first few kilometers of transport producing a population of olivine xenocrysts that are released to the fluid-rich <span class="hlt">melt</span>. Rapid ascent of the kimberlite magma causes depressurization and creates internal elastic stresses in the olivine crystals that can only be alleviated by volumetric expansion or brittle failure. On the time scales operative during kimberlite ascent volume expansion is negligible and brittle failure occurs. Small wetting angles between the fluid-rich <span class="hlt">melt</span> and olivine allow infiltration of the <span class="hlt">melt</span> into the crack. These very thin cracks (<5 µm) heal rapidly and preserve primary kimberlitic material en route to the surface. We use the electron microprobe with a focused beam (interaction volume less than 2 µm) to analyze the small volumes of material found in the healed cracks of the olivine. We analyzed for 18 elements including oxygen, which we obtained by utilizing a non-linear time dependent intensity acquisition and empirically determined mass absorption coefficients. By accurately knowing the amount of oxygen in a sample, we assign oxygen molecules to all other analyzed elements (e.g. MgO, Al2O3) and the remaining oxygen is assigned to hydrogen and carbon. The analysis total is used as a constraint on the proportion of each species. Mg/Ca ratios of the cracks vary from 0.6-5 indicating a compositional continuum between alkali-poor, carbonate-rich <span class="hlt">melt</span> and Mg-rich silicate <span class="hlt">melt</span>. OH/CO2 ratios (0-7) and other volatiles (S, F, Cl) are variable and do not correlate with any of the other major elements, consistent with a variably degassed fluid phase. Element associations indicated that Ca, Ni, Ba and Sr co-vary and are inversely related to Mg, Si, Fe, (and several other minor elements). In summary, crack-filling material is Ca and Mg-rich (up to 55 wt.% CaO+MgO), silica-poor (11-32 wt.% SiO2) and are volatile rich ( up to 28 wt.%).</p> <div class="credits"> <p class="dwt_author">Brett, R. C.; Vigouroux-Caillibot, N.; Donovan, J. J.; Russell, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/839461"> <span id="translatedtitle">Fundamentals of <span class="hlt">Melt</span>-Water Interfacial Transport Phenomena: Improved Understanding for Innovative Safety Technologies in ALWRs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The interaction and mixing of high-temperature <span class="hlt">melt</span> and water is the important technical issue in the safety assessment of water-cooled reactors to achieve ultimate <span class="hlt">core</span> coolability. For specific advanced light water reactor (ALWR) designs, deliberate mixing of the <span class="hlt">core-melt</span> and water is being considered as a mitigative measure, to assure ex-vessel <span class="hlt">core</span> coolability. The goal of this work is to provide the fundamental understanding needed for <span class="hlt">melt</span>-water interfacial transport phenomena, thus enabling the development of innovative safety technologies for advanced LWRs that will assure ex-vessel <span class="hlt">core</span> coolability. The work considers the ex-vessel coolability phenomena in two stages. The first stage is the <span class="hlt">melt</span> quenching process and is being addressed by Argonne National Lab and University of Wisconsin in modified test facilities. Given a quenched <span class="hlt">melt</span> in the form of solidified debris, the second stage is to characterize the long-term debris cooling process and is being addressed by Korean Maritime University in via test and analyses. We then address the appropriate scaling and design methodologies for reactor applications.</p> <div class="credits"> <p class="dwt_author">M. Anderson; M. Corradini; K.Y. Bank; R. Bonazza; D. Cho</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-04-26</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53595723"> <span id="translatedtitle">The <span class="hlt">melting</span> and dissolution of low-carbon steels in iron-carbon <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Direct experimental proof is presented in the paper for the role played by the mass transfer of carbon in accelerating or facilitating the <span class="hlt">melting</span> and dissolution of pure iron specimens in iron-carbon <span class="hlt">melts</span>. It is shown that pure iron may readily <span class="hlt">melt</span> in iron-carbon <span class="hlt">melts</span> even under conditions where the temperature of the molten phase is considerably below the <span class="hlt">melting</span></p> <div class="credits"> <p class="dwt_author">J. Szekely; Y. K. Chuang; J. W. Hlinka</p> <p class="dwt_publisher"></p> <p class="publishDate">1972-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007JETPL..85..410A"> <span id="translatedtitle">Sonoluminescence of elementary sulfur <span class="hlt">melt</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The sonoluminescence of liquid sulfur has been observed for temperatures of 120-180°C. The sonoluminescence intensity of the sulfur <span class="hlt">melt</span> is 109 photons/s at 120°C. As the temperature increases, the luminescence intensity decreases nonmonotonically, a maximum is observed at 160-175°C, and cavitation and luminescence cease at 180°C. The dependence obtained correlates with the temperature dependence of the viscosity of the sulfur <span class="hlt">melt</span>. The sonoluminescence spectrum obtained with a resolution of 10 nm for 130-150°C contains one band with ?max = 560 nm, the emitter of which is likely an (S+)* ion. When the <span class="hlt">melt</span> is saturated with argon, the sonoluminescence intensity increases by an order of magnitude; in this case, the spectral band shape changes only slightly. The results confirm the “electric” theory of multibubble sonoluminescence. In the process of the sonolysis of the sulfur <span class="hlt">melt</span>, biradical fragments are formed in cavitation bubbles consisting of sulfur molecules, which initially have the form of cyclooctasulfur S8. These fragments can enter into the <span class="hlt">melts</span> and can be involved in various chemical reactions. This circumstance makes it possible to recommend ultrasonic activation for reactions of sulfurization of hydrocarbons.</p> <div class="credits"> <p class="dwt_author">Abdrakhmanov, A. M.; Sharipov, G. L.; Rusakov, I. V.; Akhmetova, V. R.; Bulgakov, R. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20000094472&hterms=migration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmigration"> <span id="translatedtitle">Partial <span class="hlt">Melting</span> of the Indarch (EH4) Meteorite : A Textural, Chemical and Phase Relations View of <span class="hlt">Melting</span> and <span class="hlt">Melt</span> Migration</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">To Test whether Aubrites can be formed by <span class="hlt">melting</span> of enstatite Chondrites and to understand igneous processes at very low oxygen fugacities, we have conducted partial <span class="hlt">melting</span> experiments on the Indarch (EH4) chondrite at 1000-1500 C. Silicate <span class="hlt">melting</span> begins at 1000 C. Substantial <span class="hlt">melt</span> migration occurs at 1300-1400 C and metal migrates out of the silicate change at 1450 C and approx. 50% silicate partial <span class="hlt">melting</span>. As a group, our experiments contain three immiscible metallic <span class="hlt">melts</span> 9Si-, and C-rich), two immiscible sulfide <span class="hlt">melts</span>(Fe-and FeMgMnCa-rich) and Silicate <span class="hlt">melt</span>. Our partial <span class="hlt">melting</span> experiments on the Indarch (EH4) enstatite Chondrite suggest that igneous processes at low fO2 exhibit serveral unique features. The complete <span class="hlt">melting</span> of sulfides at 1000 C suggest that aubritic sulfides are not relicts. Aubritic oldhamite may have crystallized from Ca and S complexed in the silicate <span class="hlt">melt</span>. Significant metal-sulfide <span class="hlt">melt</span> migration might occur at relatively low degrees of silicate partial <span class="hlt">melting</span>. Substantial elemental exchange occurred between different <span class="hlt">melts</span> (e.g., between sulfide and silicate, Si between silicate and metal), a feature not observed during experiments at higher fO2. This exchange may help explain the formation of aubrites from known enstatite chondrites.</p> <div class="credits"> <p class="dwt_author">McCoy, Timothy J.; Dickinson, Tamara L.; Lofgren, Gary E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18825292"> <span id="translatedtitle"><span class="hlt">Melting</span> and freezing of water in cylindrical silica nanopores.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Freezing and <span class="hlt">melting</span> of H(2)O and D(2)O in the cylindrical pores of well-characterized MCM-41 silica materials (pore diameters from 2.5 to 4.4 nm) was studied by differential scanning calorimetry (DSC) and (1)H NMR cryoporometry. Well-resolved DSC <span class="hlt">melting</span> and freezing peaks were obtained for pore diameters down to 3.0 nm, but not in 2.5 nm pores. The pore size dependence of the <span class="hlt">melting</span> point depression DeltaT(m) can be represented by the Gibbs-Thomson equation when the existence of a layer of nonfreezing water at the pore walls is taken into account. The DSC measurements also show that the hysteresis connected with the phase transition, and the <span class="hlt">melting</span> enthalpy of water in the pores, both vanish near a pore diameter D* approximately equal to 2.8 nm. It is concluded that D* represents a lower limit for first-order <span class="hlt">melting</span>/freezing in the pores. The NMR spin echo measurements show that a transition from low to high mobility of water molecules takes place in all MCM-41 materials, including the one with 2.5 nm pores, but the transition revealed by NMR occurs at a higher temperature than indicated by the DSC <span class="hlt">melting</span> peaks. The disagreement between the NMR and DSC transition temperatures becomes more pronounced as the pore size decreases. This is attributed to the fact that with decreasing pore size an increasing fraction of the water molecules is situated in the first and second molecular layers next to the pore wall, and these molecules have slower dynamics than the molecules in the <span class="hlt">core</span> of the pore. PMID:18825292</p> <div class="credits"> <p class="dwt_author">Jähnert, S; Vaca Chávez, F; Schaumann, G E; Schreiber, A; Schönhoff, M; Findenegg, G H</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-10-21</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.C13A0562S"> <span id="translatedtitle">What controls dead-ice <span class="hlt">melting</span> under different climate conditions?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the geological record, hummocky dead-ice moraines represent the final product of the <span class="hlt">melt</span>-out of dead- ice. Processes and rates of dead-ice <span class="hlt">melting</span> in ice-<span class="hlt">cored</span> moraines and at debris-covered glaciers are commonly believed to be governed by climate. Here, backwasting rates from 14 dead-ice areas are assessed in relation to mean annual air temperature, mean summer air temperature, mean annual precipitation, mean summer precipitation, and the sum of degree days > 0 deg. C. The highest correlation was found between backwasting rate and mean annual air temperature. However, the correlation between <span class="hlt">melt</span> rates and climate parameters is low, stressing that processes and topography play a major role in governing the rates of backwasting. The rates of dead-ice <span class="hlt">melting</span> from modern glacial environments should serve as input to de-icing models for ancient dead-ice areas in order to assess the mode and duration of deposition. A challenge for future explorations of dead-ice environments is to obtain long-term records of field-based monitoring of <span class="hlt">melt</span> progression. Furthermore, many modern satellite-borne sensors have high potentials for recordings of multi-temporal Digital Elevation Models (DEMs) for detection and quantification of changes in dead-ice environments. However, time series of high-resolution aerial photographs remain essential for both visual inspection and high-resolution stereographic DEM production. Reference: Schomacker, A. 2008. What controls dead-ice <span class="hlt">melting</span> under different climate conditions? Earth- Science Reviews, in press.</p> <div class="credits"> <p class="dwt_author">Schomacker, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">321</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PEPI..228..300K"> <span id="translatedtitle">Does partial <span class="hlt">melting</span> explain geophysical anomalies?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The existence of partial <span class="hlt">melt</span> is frequently invoked to explain geophysical anomalies such as low seismic wave velocity and high electrical conductivity. I review various experimental and theoretical studies to evaluate the plausibility of this explanation. In order for a partial <span class="hlt">melt</span> model to work, not only the presence of <span class="hlt">melt</span>, but also the presence of appropriate amount of <span class="hlt">melt</span> needs to be explained. Using the mineral physics observations on the influence of <span class="hlt">melt</span> on physical properties and the physics and chemistry of <span class="hlt">melt</span> generation and transport, I conclude that partial <span class="hlt">melt</span> model for the asthenosphere with homogeneous <span class="hlt">melt</span> distribution does not work. One needs to invoke inhomogeneous distribution of <span class="hlt">melt</span> if one wishes to explain observed geophysical anomalies by partial <span class="hlt">melting</span>. However, most of models with inhomogeneous <span class="hlt">melt</span> distribution are either inconsistent with some geophysical observations or the assumed structures are geodynamically unstable and/or implausible. Therefore partial <span class="hlt">melt</span> models for the geophysical anomalies of the asthenosphere are unlikely to be valid, and some solid-state mechanisms must be invoked. The situation is different in the deep upper mantle where <span class="hlt">melt</span> could completely wet grain-boundaries and continuous production of <span class="hlt">melt</span> is likely by "dehydration <span class="hlt">melting</span>" at around 410-km. In the ultralow velocity zone in the D? layer, where continuous production of <span class="hlt">melt</span> is unlikely, easy separation of <span class="hlt">melt</span> from solid precludes the partial <span class="hlt">melt</span> model for low velocities and high electrical conductivity unless the <span class="hlt">melt</span> density is extremely close to the density of co-existing solid minerals or if there is a strong convective current to support the topography of the ULVZ region. Compositional variation such as Fe-enrichment is an alternative cause for the anomalies in the D? layer.</p> <div class="credits"> <p class="dwt_author">Karato, Shun-ichiro</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1993NIMPA.334..116I"> <span id="translatedtitle">Alloy preparation by levitation <span class="hlt">melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Levitation <span class="hlt">melting</span> is an ideal technique for the preparation of small quantities of alloys for reference material or nuclear applications. The method avoids contamination of the <span class="hlt">melt</span> and electromagnetic stirring ensures good mixing in the molten state. Evaporation losses under inert atmosphere are usually small allowing close control of alloy composition. Very dilute alloys, containing alloying additions at ppm levels, can be prepared using several dilution steps chosen to minimize errors in concentration. Different levitation methods allow the <span class="hlt">melting</span> of low or high density metal in quantities from a few grammes up to 1 kg or more, although metals with high vapour pressure or low surface tension can be difficult to handle. Good homogeneity has been demonstrated for 20 g aluminium alloy samples chill-cast into water-cooled copper moulds. Examples of alloys prepared at CBNM by levitation <span class="hlt">melting</span> are solid standards for atomic absorption spectrometry, U-Pu metal "spikes" for material accountancy measurements by mass spectrometry and alloy reference materials for reactor neutron dosimetry.</p> <div class="credits"> <p class="dwt_author">Ingelbrecht, C.; Peetermans, F.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">323</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://shullgroup.northwestern.edu/pdfpublic/ref023.pdf"> <span id="translatedtitle">Wetting autophobicity of polymer <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Numerical solutions are obtained for a set of self-consistent-field equations that give the thickness dependence of the Helmholtz energy of a polymer film. Helmholtz energies are calculated for a series of polymer <span class="hlt">melts</span> in order to illustrate some of the unique wetting behaviours that are exhibited by amorphous polymers. The primary focus is on wetting autophobicity, where the Helmholtz energy</p> <div class="credits"> <p class="dwt_author">Kenneth R. Shull</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://gallery.usgs.gov/photos/05_26_2009_nr2Tlx8KKf_05_26_2009_9"> <span id="translatedtitle">Plama Torches <span class="hlt">Melt</span> the Rock</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://gallery.usgs.gov/">USGS Multimedia Gallery</a></p> <p class="result-summary">Plasma torches at Zybek Advanced Products blaze at over 37,000 degrees Fahrenheit, <span class="hlt">melting</span> the rock mixture. __________ The USGS has created man-made moon dirt, or regolith, to help NASA prepare for upcoming moon explorations. Four tons of the simulant is expected to be made by this summer of 2009...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-05-26</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://antoine.frostburg.edu/chem/senese/101/solutions/faq/why-salt-melts-ice.shtml"> <span id="translatedtitle">Why does salt <span class="hlt">melt</span> ice?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This tutorial on the chemical interaction between salt and ice explains how molecules on the surface of the ice escape into the water (<span class="hlt">melting</span>), and how molecules of water are captured on the surface of the ice (freezing). It was created by the Chemistry Department at Frostburg State University (no, really).</p> <div class="credits"> <p class="dwt_author">Senese, Fred</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFM.V21A2077K"> <span id="translatedtitle">The infidelity of <span class="hlt">melt</span> inclusions?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Melt</span> inclusions provide important information about magmatic systems and represent unique records of magma composition and evolution. However, it is also clear that <span class="hlt">melt</span> inclusions do not necessarily constitute a petrological 'magic bullet', and potential exists for trapped <span class="hlt">melt</span> compositions to be modified by a range of inclusion-specific processes. These include trapping of diffusional boundary layers, crystallization of the host mineral after trapping and dissolution of co-trapped minerals during homogenization, diffusional exchange between trapped liquid and the host mineral and external <span class="hlt">melt</span>, and cryptic alteration of trapped material during weathering or hydrothermal alteration. It clearly important to identify when <span class="hlt">melt</span> inclusions are unmodified, and which compositional indices represent the most robust sources of petrogenetic information. In this presentation I review and discuss various approaches for evaluating compositions and compositional variations in inclusion suites. An overriding principle is that the variations evident in <span class="hlt">melt</span> inclusions should be able to be understood in terms of petrological processes that are known, or can be reasonably inferred to also effect bulk magma compositions. One common approach is to base petrological conclusions on species that should be more robust, and many workers use variations in incompatible trace elements for this purpose. However important information may also be obtained from a comparison of variations in <span class="hlt">melt</span> inclusions and the lavas that host them, and in most cases this comparison is the key to identifying inclusions and suites that are potentially suspect. Comparisons can be made between individual inclusions and lavas, although comparison of average inclusion composition and the host lava, after correction for differences in crystal fractionation, may also be valuable. An important extension of this is the comparison of the variability of different species in inclusions and host lavas. This also provides a means to directly test for effects of inclusion-specific processes through comparison between variance and diffusivity, partition coefficient or other parameters believed to drive compositional changes. Another test that is becoming more accessible is the direct comparison of trace element compositions of inclusions and host minerals, coupled with known element partitioning behavior.</p> <div class="credits"> <p class="dwt_author">Kent, A. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">327</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010EGUGA..12.8252O"> <span id="translatedtitle">Redox viscometry of ferropicrite <span class="hlt">melt</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The rheology governs the dynamics of magmas at all scales (i.e. partial <span class="hlt">melting</span>, magmatic chamber emplacement, lava flow behavior). It is also a fundamental constraint on volcanic morphology and landforms. Most terrestrial volcanic flows have moderate iron contents up to 10 wt% but some basalts show contain up to 16 wt%. These ferropicrites range from the Archean to recent, typically forming thin isolated flows near the base of thick lava piles in large igneous provinces, are not well understood. Although ferropicrites are rare on Earth's surface they are believed to be abundant on Mars. Analyses of Martian rocks (from remote sensing data, in situ measurements and meteorite analyses) display up to 20 wt% FeO. Studying these compositions will help to constrain the physical nature and evolution of the volcanism on Mars. The influence of iron on the structure and properties of magmatic <span class="hlt">melts</span>, remains controversial. Simple system investigations indicate an as yet insufficiently parameterized influence of the oxidation state of iron on the rheology and other properties of silicate <span class="hlt">melts</span>. The dependence of shear viscosity on the oxidation state of ferrosilicate <span class="hlt">melts</span> has been measured using the concentric cylinder method and a gas mixing furnace. Previously, two different simple Fe-bearing systems have been studied: (i) anorthite-diopside eutectic composition (AnDi) with variable amount of Fe (up to 20 wt%) as a basalt analog and (ii) sodium disilicate (NS2) with up to 30 wt % Fe. Two natural compositions have been previously investigated, a phonolite and a pantellerite. Here, the compositional range has been extended to the more complex ferropicrite composition using the Adirondack class rock, a typical martian basalt (with low Al content and Fe up to 18,7 wt%). The experimental procedure involves a continuous measurement of viscosity at constant temperature during stepwise reduction state. The <span class="hlt">melt</span> is reduced by flowing CO2 and then successively reducing mixtures of CO2-CO. The composition and oxidation state of the <span class="hlt">melt</span> is monitored by obtaining a <span class="hlt">melt</span> sample after each redox equilibrium step. The <span class="hlt">melts</span> are sampled by dipping an alumina rod into the sample and drawing out a drop of liquid, which is then plunged into water for quenching. The resulting glasses are analyzed by electron microprobe, and the volumetric potassium dichromate titration is employed to determine FeO content. So far we observed a very low viscosity for high iron content samples and a decrease of the viscosity with increasing Fe content. Moreover, the viscosity of all <span class="hlt">melts</span> investigated to date decreases with <span class="hlt">melt</span> reduction. The viscosity decrease is, in general, a nonlinear function of oxidation state expressed as Fe2+/Fetot and can be fitted using logarithmic equation. The range of viscosity is compared to previous experimental studies and will help to understand morphological observations.</p> <div class="credits"> <p class="dwt_author">Oryaëlle Chevrel, Magdalena; Potuzak, Marcel; Dingwell, Donald B.; Hess, Kai-Uwe</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60633642"> <span id="translatedtitle">Summary of the first three in-<span class="hlt">core</span> PAHR molten fuel pool experiments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Results from the first three Sandia in-<span class="hlt">core</span> molten pool experiments are reviewed. Incipient <span class="hlt">melt</span> of a fully enriched dry bed of UO was achieved in the first experiment while 30g of UO was <span class="hlt">melted</span> in the second. The <span class="hlt">melting</span> region developed a void surrounded by a dense crust as indicated by post-test x-radiographs. In the third experiment, a steel layer</p> <div class="credits"> <p class="dwt_author">H. G. Plein; R. J. Lipinski; G. A. Carlson; D. W. Varela</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.irsn.fr/fr/larecherche/information_scientifique/publications_documentation/bdd_publi/documents/coloss_pub_ned_2003.pdf"> <span id="translatedtitle"><span class="hlt">CORE</span> LOSS DURING A SEVERE ACCIDENT (COLOSS)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The COLOSS project is a 3-year shared-cost action which started in February 2000. The project is concerned with the consequences that <span class="hlt">core</span> degradation, occurring under Severe Accident conditions, may have on H2 production, <span class="hlt">melt</span> generation and the source term. Unresolved in-vessel risk-relevant issues are studied, through a large number of experiments such as a) UO2 and MOX dissolution by molten</p> <div class="credits"> <p class="dwt_author">B. Adroguer; P. Chatelard; J. P. Van Dorsselaere; C. Duriez; N. Cocuaud; L. Bellenfant; D. Bottomley; V. Vrtilkova; K. Mueller; W. Hering; C. Homann; W. Krauss; A. Miassoedov; M. Steinbrück; J. Stuckert; Z. Hozer; G. Bandini; J. Birchley; M. Buck; J. A. F. Benitez; E. Virtanen; S. Marguet; G. Azarian; H. Plank; M. Veshchunov; Y. Zvonarev; A. Goryachev</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/5582000"> <span id="translatedtitle">Modeling and database for <span class="hlt">melt</span>-water interfacial heat transfer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A mechanistic model is developed to predict the transition superficial gas velocity between bulk cooldown and crust-limited heat transfer regimes in a sparged molten pool with a coolant overlayer. The model has direct applications in the analysis of ex-vessel severe accidents, where molten corium interacts with concrete, thereby producing sparging concrete decomposition gases. The analysis approach embodies thermal, mechanical, and hydrodynamic aspects associated with incipient crust formation at the <span class="hlt">melt</span>/coolant interface. The model is validated against experiment data obtained with water (<span class="hlt">melt</span>) and liquid nitrogen (coolant) simulants. Predictions are then made for the critical gas velocity at which crust formation will occur for <span class="hlt">core</span> material interacting with concrete in the presence of water.</p> <div class="credits"> <p class="dwt_author">Farmer, M.T.; Spencer, B.W. (Argonne National Lab., IL (United States)); Schneider, J.P. (Illinois Univ., Urbana, IL (United States)); Bonomo, B. (Northwestern Univ., Evanston, IL (United States)); Theofanous, G. (California Univ., Berkeley, CA (United States))</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10136693"> <span id="translatedtitle">Modeling and database for <span class="hlt">melt</span>-water interfacial heat transfer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A mechanistic model is developed to predict the transition superficial gas velocity between bulk cooldown and crust-limited heat transfer regimes in a sparged molten pool with a coolant overlayer. The model has direct applications in the analysis of ex-vessel severe accidents, where molten corium interacts with concrete, thereby producing sparging concrete decomposition gases. The analysis approach embodies thermal, mechanical, and hydrodynamic aspects associated with incipient crust formation at the <span class="hlt">melt</span>/coolant interface. The model is validated against experiment data obtained with water (<span class="hlt">melt</span>) and liquid nitrogen (coolant) simulants. Predictions are then made for the critical gas velocity at which crust formation will occur for <span class="hlt">core</span> material interacting with concrete in the presence of water.</p> <div class="credits"> <p class="dwt_author">Farmer, M.T.; Spencer, B.W. [Argonne National Lab., IL (United States); Schneider, J.P. [Illinois Univ., Urbana, IL (United States); Bonomo, B. [Northwestern Univ., Evanston, IL (United States); Theofanous, G. [California Univ., Berkeley, CA (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE90003778"> <span id="translatedtitle">Heatup of the TMI-2 (Three Mile Island-2) Lower Head during <span class="hlt">Core</span> Relocation.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">An analysis has been carried out to assess the potential of a <span class="hlt">melting</span> attack upon the reactor vessel lower head and incore instrument nozzle penetration weldments during the TMI <span class="hlt">core</span> relocation event at 224 minutes. Calculations were performed to determin...</p> <div class="credits"> <p class="dwt_author">S. K. Wang J. J. Sienicki B. W. Spencer</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..15.9122C"> <span id="translatedtitle">Differentiation, mineralogy and <span class="hlt">melting</span> of Rhea</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Rhea is a medium sized icy satellite (MIS) of Saturn. It is built of mixtures of rocks and ices. The rocky component is believed to be of chondritic composition. The main component of ices is frozen H2O. Initially Rhea was built from a homogenous mixture of those two components. After accretion the temperature of the satellites increased that allowed for the separation of rocky component from the ices. During this differentiation the high density silicate grains sink in the liquid, eventually forming the central <span class="hlt">core</span>. The low density matter forms an upper layer. Analysis of the Doppler data acquired by the Cassini spacecraft yields the mass of Rhea and its gravity field with unprecedented accuracy - Iess, et al., 2007, Icarus 190, 585-593. Eventually they conclude: "The one model that fits the gravity data and is self-consistent […] is an "almost undifferentiated" Rhea, in which a very large uniform <span class="hlt">core</span> is surrounded by a relatively thin ice shell containing no rock at all". In the present paper we try to find explanation of these observations by thermal model of evolution. Comparing to our previous models, we include here also the influence of the chemical reactions. Our numerical model is based on the parameterized theory of convection combined with FDM (Finite Difference Method). The approach is based on the 1 dimensional equation of the heat transfer in spherical coordinates. The model includes sources and sinks of the heat: radiogenic heat resulting from the decay of isotopes, latent heat of <span class="hlt">melting</span>, latent heat of solidification, and chemical reactions. The heat of accretion is included as initial temperature of the accreted layer. The heat transported by convection is included by multiplying the coefficient of the heat conduction in the considered layer by the Nusselt number. We found that partial differentiation followed by uprising of light component is consistent with observations of gravity and surface of Rhea if silicate density is high (i.e. 3500 kg/m3). However, our calculation indicates that partial <span class="hlt">melting</span> is possible only for narrow range of parameters. It makes possible to determine the time of accretion of Rhea. Without consideration of chemical reaction the time from forming CAI to the end of accretion is probably from 2.9 to 4.1 My. However, if chemical reactions are included the age cannot be determined with the same precision because the observational data are in agreement with the fully differentiated model.</p> <div class="credits"> <p class="dwt_author">Czechowski, Leszek; Losiak, Anna</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011M%26PS...46..543M"> <span id="translatedtitle">Formation of pseudotachylitic breccias in the central uplifts of very large impact structures: Scaling the <span class="hlt">melt</span> formation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The processes leading to formation of sometimes massive occurrences of pseudotachylitic breccia (PTB) in impact structures have been strongly debated for decades. Variably an origin of these pseudotachylite (friction <span class="hlt">melt</span>)-like breccias by (1) shearing (friction <span class="hlt">melting</span>); (2) so-called shock compression <span class="hlt">melting</span> (with or without a shear component) immediately after shock propagation through the target; (3) decompression <span class="hlt">melting</span> related to rapid uplift of crustal material due to central uplift formation; (4) combinations of these processes; or (5) intrusion of allochthonous impact <span class="hlt">melt</span> from a coherent <span class="hlt">melt</span> body has been advocated. Our investigations of these enigmatic breccias involve detailed multidisciplinary analysis of millimeter- to meter-sized occurrences from the type location, the Vredefort Dome. This complex Archean to early Proterozoic terrane constitutes the central uplift of the originally >250 km diameter Vredefort impact structure in South Africa. Previously, results of microstructural and microchemical investigations have indicated that formation of very small veinlets involved local <span class="hlt">melting</span>, likely during the early shock compression phase. However, for larger veins and networks it was so far not possible to isolate a specific <span class="hlt">melt</span>-forming mechanism. Macroscopic to microscopic evidence for friction <span class="hlt">melting</span> is very limited, and so far chemical results have not directly supported PTB generation by intrusion of impact <span class="hlt">melt</span>. On the other hand, evidence for filling of dilational sites with <span class="hlt">melt</span> is abundant. Herein, we present a new approach to the mysterium of PTB formation based on volumetric <span class="hlt">melt</span> breccia calculations. The foundation for this is the detailed analysis of a 1.5 × 3 × 0.04 m polished granite slab from a dimension-stone quarry in the <span class="hlt">core</span> of the Vredefort Dome. This slab contains a 37.5 dm3 breccia zone. The pure <span class="hlt">melt</span> volume in 0.1 m3 PTB-bearing granitic target rock outside of the several-decimeter-wide breccia zone in the granite slab was estimated at 5.2 dm3. This amount can be divided into 4.6 dm3 <span class="hlt">melt</span> (88%), for which we have evidenced a limited material transport (at maximum, ?20 cm) and 0.6 dm3 <span class="hlt">melt</span> (12%) with, at most, grain-scale material transport, which we consider in situ formed shock <span class="hlt">melt</span>. The breccia zone itself contains about 10 dm3 of matrix (<span class="hlt">melt</span>). Assuming <span class="hlt">melt</span> exchange over 20 cm at the slab surface, between breccia zone and surrounding <span class="hlt">melt</span>-bearing host rock volume, the outer <span class="hlt">melt</span> volume is calculated to contain the same amount of <span class="hlt">melt</span> as contained by the massive breccia zone. Meso- and microscopic observations indicate <span class="hlt">melt</span> transport is more prominent from larger into smaller <span class="hlt">melt</span> occurrences. Thus, <span class="hlt">melt</span> of the breccia zone could have provided the <span class="hlt">melt</span> fill for all the small-scale PTB veins in the surrounding target rock. Extrapolating this <span class="hlt">melt</span> capacity calculation for 1 m3 PTB-bearing host rock shows that a host rock volume of this dimension is able to take up some 52 dm3 <span class="hlt">melt</span>. Scaling up 1000-fold to the outcrop scale reveals that exchange between a host rock volume of 2 m radius around a 37 m3 breccia zone could involve some 10 m3 <span class="hlt">melt</span>. These results demonstrate that large <span class="hlt">melt</span> volumes (i.e., large breccia zones) can be derived, in principle, from local reservoirs. However, strong decompression would have to apply in order to exchange these considerable <span class="hlt">melt</span> volumes, which would only be realistic during the decompression phase of impact cratering upon central uplift formation, or locally where compressive regimes acted during the subsequent down- and outward collapse of the central uplift.</p> <div class="credits"> <p class="dwt_author">Mohr-Westheide, Tanja; Reimold, Wolf Uwe</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFM.V51B0527W"> <span id="translatedtitle">Two-Stage <span class="hlt">Melting</span> Of Mantle Plumes And The Origin Of Rejuvenescent Volcanism On Oceanic Islands</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Many mid-plate oceanic volcanoes experience a rejuvenescent, or "post-erosional" phase of volcanism that occurs hundreds of thousands or million years after the main shield-building phase of volcanism has ended. The Hawaiian Islands are the best-documented example, but rejuvenescent volcanism also occurs on the Society Islands, the Marquesas, the Australs, Samoa, and Mauritius. It does not occur on near-ridge islands such as the Galapagos, the Azores, and Iceland. Rejuvenescent lavas have a number of features in common: they are erupted in small volumes, they are highly enriched in incompatible elements, and they are highly alkalic, typically basanitic to nephelenitic. All these features suggest they are quite small degree <span class="hlt">melts</span>. In addition, rejuvenescent magmas have more depleted isotopic signatures, implying they are <span class="hlt">melts</span> of more depleted sources, despite their strong incompatible element enrichment. Although isotopic signatures of these lavas are more depleted that those of the corresponding shield stage lavas, they are nevertheless not as depleted as MORB. Furthermore, the isotopic compositions of the rejuvenescent magmas rule out their sources being mixtures of plume material and MORB-source material. Thus geochemical considerations rule out both the lithosphere and the asthenosphere surrounding the plume as the source of rejuvenescent magmas; this implies the plume itself must be the source of rejuvenescent magmas. This conclusion is consistent with geophysical models of plumes. Finite difference numerical models of plume-lithosphere interaction that include both temperature and compositional viscosity dependence reveal that while most <span class="hlt">melting</span> is concentrated above the hot <span class="hlt">core</span> of the plume, a <span class="hlt">melting</span> "tail" extends hundreds of km downstream. In this tail region, lateral spreading of the plume results in a slight rising motion of the plume, and consequently, small extents of <span class="hlt">melting</span>. The problem thus becomes that of deciphering why <span class="hlt">melts</span> produced in this tail region are isotopically distinct from those produced in the main <span class="hlt">melting</span> region. We propose the following model to explain this difference: Mantle plumes are lithologically heterogeneous, consisting of eclogite or pyroxenite "plums" that have a solidus temperature several tens of degrees lower than the more refractory peridotite "pudding" in which they are embedded. Complete isotopic equilibrium is not achieved during <span class="hlt">melting</span> - either because the plums are large enough (>10-100m) or the extraction of plum <span class="hlt">melts</span> is rapid after their generation. Both the plums and the peridotite are incompatible-element enriched relative to the average depleted upper mantle, but the plums are substantially more enriched. The plums <span class="hlt">melt</span> entirely in the base of the main <span class="hlt">melting</span> region and the heat so consumed initially suppresses <span class="hlt">melting</span> of the peridotite pudding. Plum-derived <span class="hlt">melts</span> mix as they rise with <span class="hlt">melts</span> of the peridotite pudding produced higher in the main <span class="hlt">melting</span> region. This mixture of eclogitic and peridotitic <span class="hlt">melts</span> form the shield stage magmas. Material in the <span class="hlt">melting</span> "tail" has had the plums <span class="hlt">melted</span> out of it in the main <span class="hlt">melting</span> region. Low degree <span class="hlt">melting</span> of the plum-free peridotite in the <span class="hlt">melting</span> tail gives rise to rejuvenescent magmas. <span class="hlt">Melt</span> production in the tail is more or less continuous, but rejuvenescent volcanism is not. This suggests that some other factor is involved, such as lithospheric loading by adjacent volcanoes, that provides pathways to the surface for small degree tail <span class="hlt">melts</span>.</p> <div class="credits"> <p class="dwt_author">White, W. M.; Morgan, J. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6475444"> <span id="translatedtitle">Liquid jet breakup characterization with application to <span class="hlt">melt</span>-water mixing</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Severe accidents in light-water reactors could lead to the flow of molten <span class="hlt">core</span> material from the initial <span class="hlt">core</span> region of the reactor vessel to the lower plenum. Steam explosions have been predicted to occur as a result of the contact of the <span class="hlt">melt</span> with water available in the plenum. It is presently judged by many workers, that the magnitude of the energy released during such an in-vessel explosion would be insufficient to lead to failure of the containment building (SERG, 1985). A major contributing factor in this judgment is that the mass of <span class="hlt">melt</span> which would participate in the interaction would be limited by the quantity of <span class="hlt">melt</span> delivered to the lower plenum to the time of the explosion and by the limited breakup of the molten pour stream as it flows through the plenum prior to the explosion. Limited pour stream breakup would lead to limited <span class="hlt">melt</span>-water mixing and, in addition, to the existence of ''large-scale'' <span class="hlt">melt</span> masses which may lead to very inefficient thermal-to-mechanical energy conversion. The objective of this paper is to assess the available literature relevant to liquid jet breakup and to assess its implications with respect to the behavior of molten corium pour streams as they would flow from the <span class="hlt">core</span> region through the lower plenum. Uncertainties in application of the available literature are discussed. 7 refs., 2 figs.</p> <div class="credits"> <p class="dwt_author">Ginsberg, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6152356"> <span id="translatedtitle">Lower <span class="hlt">core</span> support assembly defueling plans and tools</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Prior to February 1985 it was the accepted technical opinion that little or no fuel <span class="hlt">melting</span> had occurred in the TMI-2 <span class="hlt">core</span> during the accident of March 28, 1979. However, at this time a camera was inserted between the <span class="hlt">core</span> support cylinder and the reactor vessel wall. This camera was inserted into the vessel down to the vicinity of the lower head. Large rough pieces of corium were observed. The largest of which was approximately 8 inches across. Most of the lower head of the reactor vessel appeared full of rubble. This observation demonstrated that the material in the reactor vessel lower head did not pass through the steam generators with the reactor coolant water and deposit in the lower head due to passing through a region of low velocity. Instead, the rubble material in the lower head would have to have come directly from the <span class="hlt">core</span> region above the lower head and the most likely transport method was that the <span class="hlt">core</span> had <span class="hlt">melted</span> and the <span class="hlt">core</span> material flowed to its present resting place. <span class="hlt">Core</span> <span class="hlt">melting</span> and its impact on the reactor vessel lower internals and the reactor lower head must therefore be seriously considered. In order to defuel in lower head and remove large solidified pieces of corium a large hole would have to be made through the lower <span class="hlt">core</span> support assembly (LCSA) to provide access to the lower head. This report describes the cutting planning, the cutting tools, the defueling tools and the methods of disposition of the cut pieces.</p> <div class="credits"> <p class="dwt_author">Ryan, R.F.; Blumberg, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..16.1329P"> <span id="translatedtitle">Dynamics of upper mantle rocks decompression <span class="hlt">melting</span> above hot spots under continental plates</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Numeric 2D simulation of the decompression <span class="hlt">melting</span> above the hot spots (HS) was accomplished under the following conditions: initial temperature within crust mantle section was <span class="hlt">postulated</span>; thickness of the metasomatized lithospheric mantle is determined by the mantle rheology and position of upper asthenosphere boundary; upper and lower boundaries were <span class="hlt">postulated</span> to be not permeable and the condition for adhesion and the distribution of temperature (1400-2050°C); lateral boundaries imitated infinity of layer. Sizes and distribution of lateral points, their symmetry, and maximum temperature varied between the thermodynamic condition for existences of perovskite - majorite transition and its excess above transition temperature. Problem was solved numerically a cell-vertex finite volume method for thermo hydrodynamic problems. For increasing convergence of iterative process the method of lower relaxation with different value of relaxation parameter for each equation was used. The method of through calculation was used for the increase in the computing rate for the two-layered upper mantle - lithosphere system. Calculated region was selected as 700 x (2100-4900) km. The time step for the study of the asthenosphere dynamics composed 0.15-0.65 Ma. The following factors controlling the sizes and <span class="hlt">melting</span> degree of the convective upper mantle, are shown: a) the initial temperature distribution along the section of upper mantleb) sizes and the symmetry of HS, c) temperature excess within the HS above the temperature on the upper and lower mantle border TB=1500-2000oC with 5-15% deviation but not exceed 2350oC. It is found, that appearance of decompression <span class="hlt">melting</span> with HS presence initiate primitive mantle <span class="hlt">melting</span> at TB > of 1600oC. Initial upper mantle heating influence on asthenolens dimensions with a constant HS size is controlled mainly by decompression <span class="hlt">melting</span> degree. Thus, with lateral sizes of HS = 400 km the decompression <span class="hlt">melting</span> appears at TB > 1600oC and HS temperature (THS) > 1900oC asthenolens size ~700 km. When THS = of 2000oC the maximum <span class="hlt">melting</span> degree of the primitive mantle is near 40%. An increase in the TB > 1900oC the maximum degree of <span class="hlt">melting</span> could rich 100% with the same size of decompression <span class="hlt">melting</span> zone (700 km). We examined decompression <span class="hlt">melting</span> above the HS having LHS = 100 km - 780 km at a TB 1850- 2100oC with the thickness of lithosphere = 100 km.It is shown that asthenolens size (Lln) does not change substantially: Lln=700 km at LHS = of 100 km; Lln= 800 km at LHS = of 780 km. In presence of asymmetry of large HS the region of advection is developed above the HS maximum with the formation of asymmetrical cell. Influence of lithospheric plate thicknesses on appearance and evolution of asthenolens above the HS were investigated for the model stepped profile for the TB ? of 1750oS with Lhs = 100km and maximum of THS =2350oC. With an increase of TB the Lln difference beneath lithospheric steps is leveled with retention of a certain difference to <span class="hlt">melting</span> degrees and time of the <span class="hlt">melting</span> appearance a top of the HS. RFBR grant 12-05-00625.</p> <div class="credits"> <p class="dwt_author">Perepechko, Yury; Sorokin, Konstantin; Sharapov, Victor</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFM.V51D..05G"> <span id="translatedtitle">Models for silicate <span class="hlt">melt</span> viscosity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The prediction of viscosity in silicate liquids, over the range of temperatures and compositions encountered in nature, remains one of the most challenging and elusive goals in Earth Sciences. Recent work has demonstrated that there are now sufficient experimental measurements of <span class="hlt">melt</span> viscosity to create new viscosity models to replace previous Arrhenian models [1],[2] and extend the compositional range of more recent non-Arrhenian models [3]. Most recently, [4] have developed an empirical strategy for accurately predicting viscosities over a very wide range of anhydrous silicate <span class="hlt">melt</span> compositions (e.g., rhyolite to basanite). Future models that improve upon this work, will probably extend the composition range of the model to consider, at least, H2O and other volatile components and may utilize a compositional basis that reflects <span class="hlt">melt</span> structure. In preparation for the next generation model, we explore the attributes of the three most common equations that could be used to model the non-Arrhenian viscosity of multicomponent silicate <span class="hlt">melts</span>. The equations for the non-Arrhenian temperature dependence of viscosity (? ) include: a) Vogel-Fulcher-Tammann (VFT): log ? = A + B/(T - C) b) Adam and Gibbs (AG): log ? = A + B/[T log (T/C)], and c) Avramov (Av): log ? = A + [B/T]? We use an experimental database of approximately 900 high-quality viscosity measurements on silicate <span class="hlt">melts</span> to test the ability of each equation to capture the experimental data. These equations have different merits [5]. VFT is purely empirical in nature. The AG model has a quasi-theoretical basis that links macroscopic transport properties directly to thermodynamic properties via the configurational entropy. Lastly, the model proposed by Avramov adopts a form designed to relate the fit parameter (? ) to the fragility of the <span class="hlt">melt</span>. [1] Shaw, H.R., 1972. Am J Science, 272, 438-475. [2] Bottinga Y. and Weill, D., 1972. Am J Science, 272, 438-475. [3] Hess, K.U. and Dingwell, D.B, 1996, Am Min, 81, 1297-1300. [4] D. Giordano & D.B. Dingwell, 2003. EPSL. 208, 337 (and related corrige EPSL 221, 449) [5] J.K. Russell, D. Giordano & D.B. Dingwell, 2003. Am Min 88, 1390</p> <div class="credits"> <p class="dwt_author">Giordano, D.; Russell, K.; Moretti, R.; Mangiacapra, A.; Potuzak, M.; Romano, C.; Dingwell, D. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61309885"> <span id="translatedtitle">Transient testing of an in-<span class="hlt">core</span> impedance flow sensor in a 9-rod heated bundle</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">An in-<span class="hlt">core</span> instrumentation package that utilizes impedance sensors has been developed and fabricated to measure void fraction and two-phase flow velocity. The instrumentation package was designed to survive the severe thermal environment generated in the refill-reflood stage of a <span class="hlt">postulated</span> loss-of-coolant accident and to detect small output signals from the sensors in a very noisy signal environment. An in-<span class="hlt">core</span> impedance</p> <div class="credits"> <p class="dwt_author">J. E. Hardy; W. H. Leavell; H. Liebert; J. A. Mullens</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_16");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.cs.sunysb.edu/%7Evislab/papers/melting.pdf"> <span id="translatedtitle"><span class="hlt">Melting</span> and flowing in multiphase environment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper presents a method to simulate the <span class="hlt">melting</span> and flowing phenomena with different materials in multiple phases. In such a multiphase environment, solid objects are <span class="hlt">melted</span> because of heating and the <span class="hlt">melted</span> liquid flows while interacting with the ambient air flow. Our simulation is based on a modified lattice Boltzmann method (LBM), where the fluid dynamics of the air</p> <div class="credits"> <p class="dwt_author">Ye Zhao; Lujin Wang; Feng Qiu; Arie E. Kaufman; Klaus Mueller</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.andrill.org/flexhibit/flexhibit/materials/activities/Activity5C-HowDoesMeltingIceAffectSeaLevel.pdf"> <span id="translatedtitle">How Does <span class="hlt">Melting</span> Ice Affect Sea Level?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this activity, students investigate how sea levels might rise when ice sheets and ice caps <span class="hlt">melt</span> by constructing a pair of models and seeing the effects of ice <span class="hlt">melt</span> in two different situations. Students should use their markers to predict the increase of water in each box before the ice <span class="hlt">melts</span>.</p> <div class="credits"> <p class="dwt_author">Dahlman, Luann; Andrill</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54881385"> <span id="translatedtitle">Coarse grained model of entangled polymer <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A coarse graining procedure aimed at reproducing both the chain structure and dynamics in entangled polymeric <span class="hlt">melts</span> is presented. The reference, fine scale system is a beadspring-type representation of the <span class="hlt">melt</span>. This model is used to calibrate the coarse model for a specific monodisperse <span class="hlt">melt</span> of linear chains. The coarse model is then used to represent the structure and dynamics</p> <div class="credits"> <p class="dwt_author">Abhik Rakshit</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/12571051"> <span id="translatedtitle"><span class="hlt">Melting</span>, freezing, and coalescence of gold nanoclusters</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We present a detailed molecular-dynamics study of the <span class="hlt">melting</span>, freezing, and coalescence of gold nanoclusters within the framework of the embedded-atom method. Concerning <span class="hlt">melting</span>, we find the process first to affect the surface (``premelting''), then to proceed inwards. The curve for the <span class="hlt">melting</span> temperature vs cluster size is found to agree reasonably well with predictions of phenomenological models based on</p> <div class="credits"> <p class="dwt_author">Laurent J. Lewis; Pablo Jensen; Jean-Louis Barrat</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/sciencecinema/product.biblio.jsp?osti_id=1047692"> <span id="translatedtitle"><span class="hlt">Melt</span>-spinning (Materials Preparation Center)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/sciencecinema/">ScienceCinema</a></p> <p class="result-summary"><span class="hlt">Melt</span>-spinning is a method used for producing amorphous ribbon, which can then be converted to powder. The quality of the ribbon is controlled by several processing factors. This video shows the <span class="hlt">melt</span> stream, <span class="hlt">melt</span> pool, and ribbon formation in slow motion.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.phys.uu.nl/%7Ewal/research/papers/kekonenetal2005.pdf"> <span id="translatedtitle">The 800 year long ion record from the Lomonosovfonna (Svalbard) ice <span class="hlt">core</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We present a high-resolution record of water-soluble ion chemistry from a 121 m ice <span class="hlt">core</span> spanning about 800 years. The <span class="hlt">core</span> is well dated to 2\\/3 depth using cycle counting and reference horizons and a simple but close fitting model for the lower 1\\/3 of the <span class="hlt">core</span>. This <span class="hlt">core</span> suffers from modest seasonal <span class="hlt">melt</span>, and so we present concentration data</p> <div class="credits"> <p class="dwt_author">Teija Kekonen; John Moore; Paavo Perämäki; Robert Mulvaney; Elisabeth Isaksson; Veijo Pohjola</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=PB95257150"> <span id="translatedtitle">High Resolution XPS of Crystalline and Amorphous Poly(ethylene terephthalate): A Study of Biaxially Oriented Film, Spin Cast Film and Polymer <span class="hlt">Melt</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">High resolution monochromated x-ray photoelectron spectroscopy (XPS) (<span class="hlt">core</span> line and valence band) was used to study poly(ethylene terephthalate) (PET) as biaxially oriented crystalline film, spin cast amorphous film and amorphous polymer <span class="hlt">melt</span>. On going fr...</p> <div class="credits"> <p class="dwt_author">G. Beamson D. T. Clark N. W. Hayes D. S. L. Law V. Siracusa A. Recca</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26598066"> <span id="translatedtitle">Experimental and analytical studies of <span class="hlt">melt</span> jet-coolant interactions: a synthesis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Instability and fragmentation of a <span class="hlt">core</span> <span class="hlt">melt</span> jet in water have been actively studied during the past 10 years. Several models, and a few computer codes, have been developed. However, there are, still, large uncertainties, both, in interpreting experimental results and in predicting reactor-scale processes. Steam explosion and debris coolability, as reactor safety issues, are related to the jet fragmentation</p> <div class="credits"> <p class="dwt_author">T. N. Dinh; V. A. Bui; R. R. Nourgaliev; J. A. Green; B. R. Sehgal</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61301727"> <span id="translatedtitle">Zircaloy-steam interactions during nuclear-fuel-rod heatup and <span class="hlt">melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Research by the nuclear industry and regulating agencies has shown that the oxidation and <span class="hlt">melting</span> of the Zircaloy cladding of nuclear fuel rods has a dominant influence upon the behavior of a reactor <span class="hlt">core</span> during a severe accident like TMI-2. The work presented in this dissertation addresses three important aspects of that research. First, the influence of Zircaloy oxidation and</p> <div class="credits"> <p class="dwt_author">Allison</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60056697"> <span id="translatedtitle">Theory of the iron equation of state and <span class="hlt">melting</span> curve to very high pressures</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A semiempirical equation of state for iron has been constructed by dividing the total energy into mean field, interatomic pair potential, and electronic thermal terms. The five adjustable parameters are fitted to the experimental isotherm, Hugoniot, and <span class="hlt">melting</span> curve. Superimposing the estimated pressure and temperature conditions of the presumably pure solid iron inner <span class="hlt">core</span> of the earth onto the calculated</p> <div class="credits"> <p class="dwt_author">D. A. Young; R. Grover</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/5hdrgjf2830au1fq.pdf"> <span id="translatedtitle">A granite–gabbro complex from Madagascar: constraints on <span class="hlt">melting</span> of the lower crust</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Ranomandry Complex is a Neoproterozoic, nested intrusion from central Madagascar composed of a gabbroic <span class="hlt">core</span> within a coeval peraluminous granite ring intruding pelitic metasediments. Although xenocryst entrainment and magma mixing have both contributed to marginal phases of the granite, the primary <span class="hlt">melt</span> is characterised by steep LREE\\/HREE ratios and negligible, or slightly positive, Eu anomalies. Both isotopic and trace</p> <div class="credits"> <p class="dwt_author">Andy McMillan; Nigel B. W. Harris; Marian Holness; Lewis Ashwal; Simon Kelley; Roger Rambeloson</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55117764"> <span id="translatedtitle">Partial <span class="hlt">Melting</span> of Ordinary Chondrite: Implications for Siderophile Behavior During Early Differentiation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Core</span> formation scenarios in growing planetesimals include a variety of possible physical mechanisms such as segregation in a solid or partially molten silicate body or whether or not the body was actively deforming. The resulting geochemical composition of the metal and silicate phases will also be a function of bulk composition, percent of metal <span class="hlt">melted</span> and oxygen fugacity. To explore</p> <div class="credits"> <p class="dwt_author">T. Rushmer</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850006465&hterms=natural+the+oxide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dnatural%2B%2522the%2Boxide%2522"> <span id="translatedtitle">Dynamic crystallization of silicate <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Two types of furnaces with differing temperature range capabilities were used to provide variations in <span class="hlt">melt</span> temperatures and cooling rates in a study of the effects of heterogeneous nucleation on crystallization. Materials of chondrule composition were used to further understanding of how the disequilibrium features displayed by minerals in rocks are formed. Results show that the textures of natural chondrules were duplicated. It is concluded that the <span class="hlt">melt</span> history is dominant over cooling rate and composition in controlling texture. The importance of nuclei, which are most readily derived from preexisting crystalline material, support an origin for natural chondrules based on remelting of crystalline material. This would be compatible with a simple, uniform chondrule forming process having only slight variations in thermal histories resulting in the wide range of textures.</p> <div class="credits"> <p class="dwt_author">Russell, W. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6400825"> <span id="translatedtitle">Downward heat transfer in a miscible <span class="hlt">melting</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The integrity of an ex-vessel <span class="hlt">core</span>-retention system in the event of <span class="hlt">core</span> meltdown is of concern in PAHR safety assessment. Several ex-vessel <span class="hlt">core</span> retention concepts incorporate sacrificial beds. The integrity of the ex-vessel <span class="hlt">core</span>-retention system is dependent on the directional growth of the molten pool into soluble boundaries of the sacrificial bed. Mutual dissolution of the molten pool of <span class="hlt">core</span>-debris and the sacrificial material is expected to change the thermal characteristics of the pool and thus affect the heat transfer to the boundaries. The two-dimensional simulation study of the penetration of a dense, hot liquid pool into the boundaries of a meltable, soluble solid revealed the dependency of the directional pool growth on the density ratio, rho*, of the liquid pool to the meltable solid. In the one-dimensional study of the downward penetration of the hot pool into a soluble boundary four different hydrodynamic flow regimes were identified that occurred at different ranges of rho*. The downward heat transfer enhanced beyond rho* approx. = 1.1. The present study investigates the effect of test cell geometry and material properties on the downward heat transfer in a horizontal <span class="hlt">melting</span> system.</p> <div class="credits"> <p class="dwt_author">Farhadieh, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850004653&hterms=hot+melt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2522hot%2Bmelt%2522"> <span id="translatedtitle">Thermoplastic/<span class="hlt">melt</span>-processable polyimides</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Several polyimides were prepared which show promise for aircraft composite applications. This was achieved through a systematic polymer synthesis program where the glass transition temperatures were greatly lowered when compared to the older polyimide systems. Several of the materials were shown to be hot-<span class="hlt">melt</span> processable and are attractive matrix resin candidates especially in light of their high g(sub Ic) values. At least two of these polyimides are available for evaluation and others are on the research horizon.</p> <div class="credits"> <p class="dwt_author">St.clair, T. L.; Burks, H. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/w712g85t197145j1.pdf"> <span id="translatedtitle">Centrifugal pneumatic disintegration of <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">UDC 621.762.224 In the manufacture of metal powders extensive use is made of the pneumatic method [1] of atomizing <span class="hlt">melts</span> with compressed gas streams. However, even at considerable specific rates of flow (--0.5--1 NTP m 3 per 1 kg of product) and high pressures (-1.5--2 MPa) of the gas (often an expensive inert gas which is in short supply) it</p> <div class="credits"> <p class="dwt_author">Sh. M. Sheikhaliev; O. A. Ivanov; S. A. Areshkin</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60289880"> <span id="translatedtitle">Critical scattering in polymer <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Critical phenomena in two classes of polymer <span class="hlt">melts</span> have been examined by small-angle neutron scattering (SANS); single component block polymers which undergo an order-disorder phase transition, and binary polymer mixtures which exhibit classical liquid-liquid phase separation behavior. A model set of 1,4-polybutadiene-1,2-polybutadiene diblock copolymers containing perdeuterated 1,4-polybutadiene blocks were investigated by SANS in the disordered state. The SANS spectra exhibit</p> <div class="credits"> <p class="dwt_author">F. S. Bates; M. A. Hartney; G. D. Wignall</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008PlST...10..344Y"> <span id="translatedtitle">Application of In-Flight <span class="hlt">Melting</span> Technology by RF Induction Thermal Plasmas to Glass Production</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">An innovative in-flight glass <span class="hlt">melting</span> technology with induced thermal plasmas was developed for the purpose of energy conservation and environmental protection. Two-dimensional modeling was used to simulate the thermofluid fields in the plasma torch. The in-flight <span class="hlt">melting</span> behavior of glass raw material was investigated by various analysis methods. Results showed that the plasma temperature was up to 10000 K with a maximum velocity over 30 m/s, which made it possible to <span class="hlt">melt</span> the granulated glass raw material within milliseconds. The carbonates in the raw material decomposed completely and the compounds in the raw material attainted 100% vitrification during the in-flight time from the nozzle exit to substrate. The particle <span class="hlt">melting</span> process is similar to the unreacted-<span class="hlt">core</span> shrinking model.</p> <div class="credits"> <p class="dwt_author">Yao, Yaochun; M. Hossain, M.; Watanabe, T.; Funabiki, F.; Yano, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=382884"> <span id="translatedtitle">DNA sequencing and <span class="hlt">melting</span> curve.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The dependence of DNA absorbance (for light at about 260 nm) on temperature is related to a specific DNA sequence structure in the vicinity of DNA thermal denaturation (the so-called DNA <span class="hlt">melting</span> or coiling). A straightforward analysis of the experimental DNA <span class="hlt">melting</span> curve allows us to determine the lengths, the A+T content, and the location in DNA of certain domains. In the case of a specific DNA fragmentation, the order of fragments in DNA can be learned from this analysis, nondestructively and quickly, without fractionating the fragments and other methods of fragmentation. If the DNA nucleotide sequence is known except for some sites and uncertain portions, the analysis determines these sites and the accuracy of the sequence at the portions. This information may complement exact methods of DNA sequencing. The proposed analysis is applied to bacteriophage phiX174, whose <span class="hlt">melting</span> curve is known. The results are compared to and found to be in an excellent agreement with the known phiX174 nucleotide sequence.</p> <div class="credits"> <p class="dwt_author">Azbel, M Y</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008JChPh.129s4302H"> <span id="translatedtitle"><span class="hlt">Melting</span> scenario in metallic clusters</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The isothermal Brownian-type molecular dynamics simulation has been applied to study the <span class="hlt">melting</span> behavior of bimetallic clusters. It was found that the specific heat and Lindermann-like parameter customarily used in bulk system to describe solid-liquid transition show incongruity in the predicted <span class="hlt">melting</span> temperature Tmelt. The underlying mechanisms that lead to the incompatibility of Tmelt separately deduced from these two quantities were analyzed further. To gain insight into the <span class="hlt">melting</span> behavior, we calculated in addition the velocity autocorrelation function and its Fourier transform, the power spectrum, and extracted from them the Tmelt. It appears that the Tmelt inferred from the latter quantities is closer to that deduced from the principal peak position of specific heat. Two bimetallic clusters, namely, Ag1Cu13 and Au1Cu13, were selected for a thorough investigation. In the context of cluster morphology, we scrutinized the atomic distributions of Ag1Cu13, Au1Cu13, and Cu14 and effected a comparative study between a bimetallic cluster and a pure cluster so as to learn from comparison the differences in the thermal reaction of atoms, in particular, the impurity atom in the bimetallic cluster. On analyzing the dynamical data, we observed at a lower temperature (T<<Tmelt) migrational relocation of atoms whose dynamics was superimposed at an intermediate temperature (T<Tmelt) by permutations between atoms, and at a higher temperature (T~Tmelt), liquidlike or even gaslike behavior.</p> <div class="credits"> <p class="dwt_author">Hsu, P. J.; Luo, J. S.; Lai, S. K.; Wax, J. F.; Bretonnet, J.-L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-11-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return 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href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a style="font-weight: bold;">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_20");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1983CoMP...84..345T"> <span id="translatedtitle"><span class="hlt">Melting</span> kinetics of a plagioclase feldspar</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Partial <span class="hlt">melting</span> experiments on plagioclase feldspar have been carried out to investigate textures and kinetics of the <span class="hlt">melting</span>. A labradorite single crystal was heated at one atmosphere pressure and temperatures within its <span class="hlt">melting</span> interval as a function of time. So called honeycomb, fingerprint, or sieve textures were produced except for the runs just below the liquidus. The <span class="hlt">melting</span> was initiated by heterogeneous nucleation of <span class="hlt">melt</span> at the surface and/or interior (cracks and possively dislocations) of the crystal. The pattern of the <span class="hlt">melt</span> is dendritic with a few ?m arm spacing. After the <span class="hlt">melt</span> develops throughout the crystal, the volumes of <span class="hlt">melt</span> and residual crystal become larger and smaller, respectively, without changing the arm spacings. The <span class="hlt">melt</span> is homogeneous and has the approximate temperature dependent liquidus composition irrespective of the time. There are compositional gradients in the residual crystal after short periods of <span class="hlt">melting</span>. The An content of the crystals increases with increasing time until it finally reaches equilibrium with the <span class="hlt">melt</span> after several thousands minutes of heating. It is concluded that the enlargement of the <span class="hlt">melt</span>, the main process of the <span class="hlt">melting</span>, is controlled by diffusion in the crystal. The fact that partial <span class="hlt">melts</span> have the composition of the equilibrium liquidus even from the first several minutes strongly suggests that the local equilibrium at the crystal-liquid interface is satisfied during the <span class="hlt">melting</span>. Some of the honeycomb, fingerprint, and sieve textures found in xenoliths and phenocrysts of sodic plagioclase in volcanic rocks would be caused by heating events (such as magma mixing) during which temperatures of magmas were temporarily higher than the solidus of some of the minerals.</p> <div class="credits"> <p class="dwt_author">Tsuchiyama, Akira; Takahashi, Eiichi</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5465736"> <span id="translatedtitle"><span class="hlt">Core</span> tests help prevent formation damage in horizontal wells</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Simulating drilling mud invasion in <span class="hlt">cores</span> helped determine and eliminate the damaging effects of various mud systems prior to the drilling of a horizontal well in Canada. Formation damage is highly reservoir specific. General damage classifications according to rock and fluid type can be <span class="hlt">postulated</span>, but specific tests are necessary to evaluate precisely the primary potential mechanisms of damage for each lithofacies. Proper testing and <span class="hlt">core</span> preparation procedures must be followed to ensure that results are representative. This article outlines <span class="hlt">core</span> displacement test methodology and presents the results of two <span class="hlt">core</span> displacement studies. The findings of these studies are substantiated by actual production data. These results illustrate that although damage from a drilling fluid cannot be eliminated in horizontal drilling, it can be minimized.</p> <div class="credits"> <p class="dwt_author">Beatty, T.; Hebner, B.; Hiscock, R. (PanCanadian Petroleum Ltd., Calgary, Alberta (Canada)); Bennion, D.B. (Hycal Energy Research Labs. Ltd., Calgary, Alberta (Canada))</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-08-02</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1994Metic..29R.472H"> <span id="translatedtitle">Experimental studies of <span class="hlt">core</span> formation: Application to asteroidal bodies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The question of how metallic <span class="hlt">cores</span> form reduces to the fluid dynamic problem of understanding the surface tension between metallic <span class="hlt">melts</span> and silicates. This problem was addressed by performing experiments to determine the surface tensions between metallic <span class="hlt">melts</span> with variable S contents and silicate phases; olivine, for which data were presented last year; and orthopyroxene, for which we now have complete data. Experiments were conducted in a piston-cylinder apparatus at P = 1 GPa and T = 1250 - 1450 C. Textural and chemical equilibration was confirmed in several ways. The dihedral 'wetting' angles (Theta) were measured from high-resolution photomicrographs using a 10x optical protractor; 100-400 measurements were made for each experiment. The dihedral angle is related to the ratio of interfacial energies. The extent to which a <span class="hlt">melt</span> is interconnected along grain boundaries, and hence able to flow and segregate, depends on the value of (Theta) and the fraction of <span class="hlt">melt</span> present. In the experiments where dense metallic <span class="hlt">melt</span> drained away, the disconnect (Theta) values match the theoretical predictions. Since data exist for the pertinent solid-solid energies, the liquid interfacial energies can be computed from measured (Theta) values. Moreover, similar data exist on the systems: olivine, orthopyroxene, and clinopyroxene in contact with basalt liquid. Ratios of the three solid-solid energies can be computed and the ratios are in good agreement with our data. This indicates a negligible effect due to gross difference in <span class="hlt">melt</span> composition. The clinopyroxene-metallic <span class="hlt">melt</span> systems can be extrapolated to acquire a complete set of data for the major silicate phases expected in planetary interiors. Ordinary chondrites typically contain about 4 vol% FeS. For this volume percentage, the system will interconnect at (Theta) values of 75 deg, very close to that predicted for eutectic <span class="hlt">melts</span> in contact with silicates at 1000 C. Element distributions between mantle and <span class="hlt">core</span> should therefore be computed on the basis of metallic <span class="hlt">melt</span>-solid silicate in most cases.</p> <div class="credits"> <p class="dwt_author">Herpfer, M. A.; Larimer, J. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/15031988"> <span id="translatedtitle">Coeval Ar40\\/Ar39 ages of 65.0 million years ago from Chicxulub crater <span class="hlt">melt</span> rock and Cretaceous-Tertiary boundary tektites</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Ar-40\\/Ar-39 dating of drill-<span class="hlt">core</span> samples of a glassy <span class="hlt">melt</span> rock recovered from beneath a massive impact breccia contained with the 180-kilometer subsurface Chicxulub crater yields well-behaved incremental heating spectra with a mean plateau age of 64.98 +\\/- 0.05 million years ago (Ma). The glassy <span class="hlt">melt</span> rock of andesitic composition was obtained from <span class="hlt">core</span> 9 (1390 to 1393 meters) in the</p> <div class="credits"> <p class="dwt_author">Carl C. Swisher III; Jose M. Grajales-Nishimura; Alessandro Montanari; Stanley V. Margolis; Philippe Claeys; Walter Alvarez; Paul Renne; Esteban Cedillo-Pardo; Florentin J.-M. R. Maurrasse; Garniss H. Curtis; J. Smit; M. O. McWilliams</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JCAP...10..017K"> <span id="translatedtitle">String <span class="hlt">melting</span> in a photon bath</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We compute the decay rate of a metastable cosmic string in contact with a thermal bath by finding the instanton solution. The new feature is that this decay rate is found in the context of non thermal scalar fields in contact with a thermal bath of photons. In general, to make topologically unstable strings stable, one can couple them to such a bath. The resulting plasma effect creates metastable configurations which can decay from the false vacuum to the true vacuum. In our specific set-up, the instanton computation is realized for the case of two out-of-equilibrium complex scalar fields: one is charged and coupled to the photon field, and the other is neutral. New effects coming from the thermal bath of photons make the radius of the nucleated bubble and most of the relevant physical quantities temperature-dependent. However, the temperature appears in a different way than in the purely thermal case, where all scalar fields are in thermal equilibrium. As a result of the tunneling, the <span class="hlt">core</span> of the initial string <span class="hlt">melts</span> while bubbles of true vacuum expand at the speed of light.</p> <div class="credits"> <p class="dwt_author">Karouby, Johanna</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014CoMP..167..974T"> <span id="translatedtitle">Geochemistry of spinel-hosted amphibole inclusions in abyssal peridotite: insight into secondary <span class="hlt">melt</span> formation in <span class="hlt">melt</span>-peridotite reaction</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Spinel-hosted hydrous silicate mineral inclusions are often observed in dunite and troctolite as well as chromitite. Their origin has been expected as products associated with <span class="hlt">melt</span>-peridotite reaction, based on the host rock origin. However, the systematics in mineralogical and geochemical features are not yet investigated totally. In this study, we report geochemical variations of the spinel-hosted pargasite inclusions in reacted harzburgite and olivine-rich troctolite collected from Atlantis Massif, an oceanic <span class="hlt">core</span> complex, in the Mid-Atlantic Ridge. The studied samples are a good example to examine geochemical variations in the inclusions because the origin and geological background of the host rocks have been well constrained, such as the reaction between MORB <span class="hlt">melt</span> and depleted residual harzburgite beneath the mid-ocean ridge spreading center. The trace-element compositions of the pargasite inclusions are characterized by not only high abundance of incompatible elements but also the LREE and HFSE enrichments. Distinctive trace-element partitioning between the pargasite inclusion and the host-rock clinopyroxene supports that the secondary <span class="hlt">melt</span> instantaneously formed by the reaction is trapped in spinel and produces inclusion minerals. While the pargasite geochemical features can be interpreted by modal change reaction of residual harzburgite, such as combination of orthopyroxene decomposition and olivine precipitation, degree of the LREE enrichment as well as variation of HREE abundance is controlled by <span class="hlt">melt</span>/rock ratio in the reaction. The spinel-hosted hydrous inclusion could be embedded evidence indicating <span class="hlt">melt</span>-peridotite reaction even if reaction signatures in the host rock were hidden by other consequent reactions.</p> <div class="credits"> <p class="dwt_author">Tamura, Akihiro; Morishita, Tomoaki; Ishimaru, Satoko; Arai, Shoji</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009PhRvB..79h5426P"> <span id="translatedtitle">Partial <span class="hlt">melting</span> mechanisms of embedded nanocrystals</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Understanding the <span class="hlt">melting</span> mechanisms of nanocrystals embedded in solids is of great current interest since both the synthesis and modification of such systems frequently involve the use of high temperatures. Using molecular-dynamics computer simulations we study the <span class="hlt">melting</span> mechanisms of Cu, Ag, and Au nanoclusters embedded in metal matrices and Si nanocrystals in amorphous silica. The results show that nanocrystals embedded in a solid bulk material with a higher <span class="hlt">melting</span> temperature exhibit complex <span class="hlt">melting</span> behavior and can even, in the same system, exhibit four distinct stages prior to full <span class="hlt">melting</span> of the system.</p> <div class="credits"> <p class="dwt_author">Pakarinen, J. A.; Backman, M.; Djurabekova, F.; Nordlund, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMDI12A..07M"> <span id="translatedtitle">Translation and convection of Earth's inner <span class="hlt">core</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The image of the inner <span class="hlt">core</span> growing slowly at the center of the Earth by gradual cooling and solidification of the surrounding liquid outer <span class="hlt">core</span> is being replaced by the more vigorous image of a ``deep foundry'', where <span class="hlt">melting</span> and crystallization rates exceed by many times the net growth rate. Recently, a particular mode of convection, called translation, has been put forward as an important mode of inner <span class="hlt">core</span> dynamics because this mechanism is able to explain the observed East-West asymmetry of P-wave velocity and attenuation (Monnereau et al. 2010). Translation is a pure solid displacement of the inner <span class="hlt">core</span> material (solid iron) within its envelop, implying crystallization of entering iron on one side of the inner <span class="hlt">core</span> and <span class="hlt">melting</span> on the opposite side. Translation is consistent with multiple scattering models of wave propagation. If they do not experience deformation, iron crystals grow as they transit from one hemisphere to the other. Larger crystals constituting a faster and more attenuating medium, a translation velocity of some cm/yr (about ten times the growth rate) is enough to account for the superficial asymmetry observed for P-wave velocity and attenuation, with grains of a few hundred meters on the crystallizing side (West) growing up to a few kilometers before <span class="hlt">melting</span> on the East side, and a drift direction located in the equatorial plane. Among all hypotheses that have been proposed to account for the seismic asymmetry, translation is the only one based on a demonstrated link between the seismic data and the proposed dynamics, notably through a model of seismic wave propagation. This mechanism was also proposed to be responsible for the formation of a dense layer at the bottom of the outer <span class="hlt">core</span>, since the high rate of <span class="hlt">melting</span> and crystallization would release a liquid depleted in light elements at the surface of the inner <span class="hlt">core</span> (Alboussiere et al 2010). This would explain the anomalously low gradient of P wave velocity in the lowermost 200 km of the outer <span class="hlt">core</span>. Translation is a particular solution of Navier-Stokes equation with permeable boundary conditions, but depending on the viscosity of the solid <span class="hlt">core</span>, modes with higher spherical harmonics degree can develop. At low viscosity, these modes can be dominant and dissipate the degree l=1 of thermal heterogeneities. Hence, a viscosity threshold may be expected below which translation cannot take place, thereby constraining the viscosity of iron at inner <span class="hlt">core</span> conditions. Using a hybrid finite-difference spherical harmonics Navier-Stokes solver, we investigate the interplay between translation and convection in a 3D spherical model with permeable boundary conditions. Our numerical simulations show the dominance of pure translation for viscosities of the inner <span class="hlt">core</span> higher than 5 x 1018 Pas. Translation is almost completely hampered by convective motions for viscosities lower than 1017 Pas and the phase change becomes an almost impermeable boundary. Between these values, a well developed circulation at the harmonic degree l=1 persists, but composed of localized cold downwellings, a passive upward flow taking place on the opposite side (the <span class="hlt">melting</span> side). Such a convective structure remains compatible with the seismic asymmetry. Alboussiere, T., Deguen, R., Melzani, M., 2010. Nature 466 (7307), 744-U9. Monnereau, M., Calvet, M., Margerin, L., Souriau, A., 2010. Science 328 (5981), 1014-1017.</p> <div class="credits"> <p class="dwt_author">Monnereau, M.; Calvet, M.; Margerin, L.; Mizzon, H.; Souriau, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19890023540&hterms=gARNETS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DgARNETS"> <span id="translatedtitle">Martian mantle primary <span class="hlt">melts</span> - An experimental study of iron-rich garnet lherzolite minimum <span class="hlt">melt</span> composition</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The minimum <span class="hlt">melt</span> composition in equilibrium with an iron-rich garnet lherzolite assemblage is ascertained from a study of the liquidus relations of iron-rich basaltic compositions at 23 kb. The experimentally determined primary <span class="hlt">melt</span> composition and its calculated sodium content reveal that Martian garnet lherzolite minimum <span class="hlt">melts</span> are picritic alkali olivine basalts. Martian primary <span class="hlt">melts</span> are found to be more picritic than terrestrial garnet lherzolite primary <span class="hlt">melts</span>.</p> <div class="credits"> <p class="dwt_author">Bertka, Constance M.; Holloway, John R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/h7482w8888h1p03x.pdf"> <span id="translatedtitle">The <span class="hlt">melting</span> and dissolution of low-carbon steels in iron-carbon <span class="hlt">melts</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Direct experimental proof is presented in the paper for the role played by the mass transfer of carbon in accelerating or\\u000a facilitating the <span class="hlt">melting</span> and dissolution of pure iron specimens in iron-carbon <span class="hlt">melts</span>. It is shown that pure iron may readily\\u000a <span class="hlt">melt</span> in iron-carbon <span class="hlt">melts</span> even under conditions where the temperature of the molten phase is considerably below the <span class="hlt">melting</span></p> <div class="credits"> <p class="dwt_author">J. Szekely; Y. K. Chuang; J. W. Hlinka</p> <p class="dwt_publisher"></p> <p class="publishDate">1972-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/554203"> <span id="translatedtitle"><span class="hlt">Melting</span> by temperature-modulated calorimetry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Well-crystallized macromolecules <span class="hlt">melt</span> irreversibly due to the need of molecular nucleation, while small molecules <span class="hlt">melt</span> reversibly as long as crystal nuclei are present to assist crystallization. Furthermore, imperfect crystals of low-molar-mass polymers may have a sufficiently small region of metastability between crystallization and <span class="hlt">melting</span> to show a reversing heat-flow component due to <span class="hlt">melting</span> of poor crystals followed by crystallization of imperfect crystals which have insufficient time to perfect before the modulation switches to heating and <span class="hlt">melts</span> the imperfect crystals. Many metals, in turn. <span class="hlt">melt</span> sharply and reversibly as long as nuclei remain after <span class="hlt">melting</span> for subsequent crystallization during the cooling cycle. Their analysis is complicated, however, due to thermal conductivity limitations of the calorimeters. Polymers of sufficiently high molar mass, finally, show a small amount of reversible. local <span class="hlt">melting</span> that may be linked to partial <span class="hlt">melting</span> of individual molecules. Experiments by temperature-modulated calorimetry and model calculations are presented. The samples measured included poly(ethylene terephthalate)s, poly(ethylene oxide)s, and indium. Two unsolved problems that arose from this research involve the origin of a high, seemingly stable, reversible heat capacity of polymers in the <span class="hlt">melting</span> region, and a smoothing of <span class="hlt">melting</span> and crystallization into a close-to-elliptical Lissajous figure in a heat-flow versus sample-temperature plot.</p> <div class="credits"> <p class="dwt_author">Wunderlich, B.; Okazaki, Iwao; Ishikiriyama, Kazuhiko; Boller, A. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry]|[Oak Ridge National Lab., TN (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004APS..MAR.C1015X"> <span id="translatedtitle">Double Reversible <span class="hlt">Melting</span> of Isotactic Polystyrene</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Quasi-isothermal temperature modulated differential scanning calorimetry (TMDSC) has been used to study the reversible crystallization and <span class="hlt">melting</span> of isotactic polystyrene (iPS). IPS was cold crystallized at 140 °C or 170 °C until completion of crystallization, then heated from below the glass transition (Tg) to above the <span class="hlt">melting</span> point (Tm) using step-wise temperature increase, with small amplitude temperature oscillation for 20 min. at each step. Reversible heat capacity measurements reveal existence of a small amount of locally reversible <span class="hlt">melting</span> and crystallization. We observe two small reversible <span class="hlt">melting</span> peaks for iPS samples cold crystallized either at the lower or at the higher temperature. The reversible <span class="hlt">melting</span> peaks are located on the higher temperature side of two major endothermic peaks (Tm1 and Tm2) seen in regular (non-modulated) scanning calorimetry. In quasi-isothermal TMDSC, the portion of the crystallized chain with lower thermal stability <span class="hlt">melts</span> first, and the molecules that are attached to these chains <span class="hlt">melt</span> at the higher temperature end of the correspondent population. These portions demonstrate locally reversible <span class="hlt">melting</span> and show a tiny reversible <span class="hlt">melting</span> peak associated with the lower temperature endothermic peak (at Tm1). Molecules attached to the portion of chain with higher thermal stability (having higher <span class="hlt">melting</span> temperature) show their reversible <span class="hlt">melting</span> peak in association with the higher temperature endothermic peak (at Tm2).</p> <div class="credits"> <p class="dwt_author">Xu, Hui; Cebe, Peggy</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/501519"> <span id="translatedtitle">Late-phase <span class="hlt">melt</span> progression experiment: MP-2. Results and analysis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">In-pile experiments addressing late-phase processes in Light Water Reactors (LWRs) were performed in the Annular <span class="hlt">Core</span> Research Reactor (ACRR) at Sandia National Laboratories. <span class="hlt">Melt</span> Progression (MP) experiments were designed to provide information to develop and verify computer models for analysis of LWR <span class="hlt">core</span> damage in severe accidents. Experiments examine the formation and motion of ceramic molten pools in disrupted reactor <span class="hlt">core</span> regions. The MP-2 experiment assembly consisted of: (1) a rubble bed of enriched UO{sub 2} and ZrO{sub 2} simulating severely disrupted reactor <span class="hlt">core</span> regions, (2) a ceramic/metallic crust representing blockage formed by early phase <span class="hlt">melting</span>, relocation, and refreezing of <span class="hlt">core</span> components, and (3) an intact rod stub region that remained in place below the blockage region. The test assembly was fission heated in the central cavity of the ACRR at an average rate of about 0.2 KA, reaching a peak molten pool temperature around 3400 K. <span class="hlt">Melting</span> of the debris bed ceramic components was initiated near the center of the bed. The molten material relocated downward, refreezing to form a ceramic crust near the bottom of the rubble bed. As power levels were increased, the crust gradually remelted and reformed at progressively lower positions in the bed until late in the experiment when it penetrated into and attacked the ceramic/metallic blockage. The metallic components of the blockage region <span class="hlt">melted</span> and relocated to the bottom of the intact rod stub region before the ceramic <span class="hlt">melt</span> penetrated the blockage region from above. The ceramic pool penetrated halfway into the blockage region by the end of the experiment. Measurements of thermal response and material relocation are compared to the results of the computer simulations. Postexperiment examination of the assembly with the associated material interactions and metallurgy are also discussed in detail with the analyses and interpretation of results. 16 refs., 206 figs., 24 tabs.</p> <div class="credits"> <p class="dwt_author">Gasser, R.D.; Gauntt, R.O.; Bourcier, S.C. [and others</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17733504"> <span id="translatedtitle">Devon island ice cap: <span class="hlt">core</span> stratigraphy and paleoclimate.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Valuable paleoclimatic information can be gained by studying the distribution of <span class="hlt">melt</span> layers in deep ice <span class="hlt">cores</span>. A profile representing the percentage of ice in <span class="hlt">melt</span> layers in a <span class="hlt">core</span> drilled from the Devon Island ice cap plotted against both time and depth shows that the ice cap has experienced a period of very warm summers since 1925, following a period of colder summers between about 1600 and 1925. The earlier period was coldest between 1680 and 1730. There is a high correlation between the <span class="hlt">melt</span>-layer ice percentage and the mass balance of the ice cap. The relation between them suggests that the ice cap mass balance was zero (accumulation equaled ablation) during the colder period but is negative in the present warmer one. There is no firm evidence of a present cooling trend in the summer conditions on the ice cap. A comparison with the <span class="hlt">melt</span>-layer ice percentage in <span class="hlt">cores</span> from the other major Canadian Arctic ice caps shows that the variation of summer conditions found for the Devon Island ice cap is representative for all the large ice caps for about 90 percent of the time. There is also a good correlation between <span class="hlt">melt</span>-layer percentage and summer sea-ice conditions in the archipelago. This suggests that the search for the northwest passage was influenced by changing climate, with the 19th-century peak of the often tragic exploration coinciding with a period of very cold summers. PMID:17733504</p> <div class="credits"> <p class="dwt_author">Koerner, R M</p> <p class="dwt_publisher"></p> <p class="publishDate">1977-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3415377"> <span id="translatedtitle">Polymer Micelles with Crystalline <span class="hlt">Cores</span> for Thermally Triggered Release</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Interest in the use of poly(ethylene glycol)-b-polycaprolactone diblock copolymers in a targeted, magnetically triggered drug delivery system has led to this study of the phase behavior of the polycaprolactone <span class="hlt">core</span>. Four different diblock copolymers were prepared by the ring opening polymerization of caprolactone from the alcohol terminus of poly(ethylene glycol) monomethylether, Mn ~ 2,000. The critical micelle concentration depended on the degree of polymerization for the polycaprolactone block and was in the range of 2.9 to 41 mg/L. Differential scanning calorimetry curves for polymer solutions with a concentration above the critical micelle concentration showed a <span class="hlt">melting</span> endotherm in the range of 40 to 45°C, indicating the polycaprolactone <span class="hlt">core</span> was semicrystalline. Pyrene was entrapped in the micelle <span class="hlt">core</span> without interfering with the ability of the polycaprolactone to crystallize. When the polymer solution was heated above the <span class="hlt">melting</span> point of the micelle <span class="hlt">core</span>, the pyrene was free to leave the <span class="hlt">core</span>. Temperature dependent measurements of the critical micelle concentration and temperature dependent dynamic light scattering showed the micelles remain intact at temperatures above the <span class="hlt">melting</span> point of the polycaprolactone <span class="hlt">core</span>.</p> <div class="credits"> <p class="dwt_author">Glover, Amanda L.; Nikles, Sarah M.; Nikles, Jacqueline A.; Brazel, Christopher S.; Nikles, David E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20000011339&hterms=medicina&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmedicina"> <span id="translatedtitle"><span class="hlt">CORE</span> Operations Center</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This report gives an overall view of the <span class="hlt">CORE</span> program at Goddard Space Flight Center (GSFC). It summarizes the different <span class="hlt">CORE</span> sessions and gives information about the technical staff. The outlook summarizes the evolution of the different <span class="hlt">CORE</span> programs.</p> <div class="credits"> <p class="dwt_author">Thomas, Cynthia; Vandenberg, Nancy</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMMR31A2204T"> <span id="translatedtitle">Possible Role of Hydrogen in the Earth <span class="hlt">Core</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Possible role of hydrogen in the Earth <span class="hlt">core</span> has been discussed by Stevenson (1977) and demonstrated experimentally by Fukai (1984), Okuchi (1997) and others. Planetary theory proposes a possibility of hydrogen incorporation in Earth's magma ocean from ambient solar nebula gas (Ikoma & Genda 2005, Genda & Ikoma 2008). More recently, migration of snow line during planet formation was examined (Min et al., 2010; Oka et al, 2011) and it was proposed that the Earth building material originally contained abundant water as ice and hydrous minerals. Therefore, it is very important to investigate the fate of water in the planet building process and clarify the role of hydrogen in the planetary <span class="hlt">core</span>. Using SPring-8 synchrotron (NaCl capsule, LiAlH4 as hydrogen source), we determined the <span class="hlt">melting</span> curve of FeH up to 20 GPa under hydrogen saturated conditions (Sakamaki, Takahashi et al, 2009). Observed <span class="hlt">melting</span> point is below 1300C and has a very small dT/dP slope. By extrapolating the <span class="hlt">melting</span> curve using Lindeman's law, we proposed that hydrogen could lower the <span class="hlt">melting</span> temperature of the Earth <span class="hlt">core</span> by more than 1500K than current estimate. Here we report our new experiments using SPring-8 synchrotron (single crystal diamond capsule, water as hydrogen source). Hydrogen concentration and <span class="hlt">melting</span> temperature of FeHx that coexists with hydrous mantle minerals were determined at 15-20GPa and 1000-1600C. We show that 1) hydrogen concentration in FeHx at 1000C, coexisting with hydrous-B and ringwoodite is approximately X=0.6. 2) Upon heating, hydrous-B decomposes and hydrogen strongly partitions into FeHx (X=0.8~1.0) than ringwoodite. 3) FeHx that coexists with ringwoodite <span class="hlt">melts</span> between ~1300C (solidus) and ~1600C (liquidus). Combined our new experiments with those by Sakamaki et al (2009) and Shibazaki et al (2009), partitioning of hydrogen between proto-<span class="hlt">core</span> and primitive mantle is discussed. We propose that >90% of water in the source material may have entered the Earth <span class="hlt">core</span>. Given large hydrogen concentration in the Earth <span class="hlt">core</span>, temperature of the outermost <span class="hlt">core</span> could be as low as that of lower mantle adiabat. Presence of the light element-rich layer at the top 300km layer of the outer <span class="hlt">core</span> (Helffrich & Kaneshima, 2010) may be easily understood if there is no temperature gap between the <span class="hlt">core</span> and the lower mantle.</p> <div class="credits"> <p class="dwt_author">Takahashi, E.; Imai, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008SPIE.7050E..32A"> <span id="translatedtitle">Hard-<span class="hlt">core</span> liquid-crystal fibers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Self-organized liquid-crystal filamentary forms arise in many mixtures of the smectogen compounds at the transition from the isotropic <span class="hlt">melt</span>. In some mixtures, a subsequent phase transition to the crystal or crystal smectic phase occurs at the <span class="hlt">core</span> of the filaments. The resulting hard-<span class="hlt">core</span> fibers act as anisotropic cylindrical lenses composed of the crystalline <span class="hlt">core</span> surrounded by the nematic shell. In this work, the filaments, referred to as nematoids, have been obtained in several binary mixtures based on five mesogens: 4,4'-dipentylazoxybenzene, 4-dodecyloxy-4'- pentylbiphenyl, 4-hexyl-4'nonyloxybiphenyl, 4-acetyl-4'-dodecylbiphenyl and 4''-pentylcyclohexyl 4-(4'- pentylcyclohexyl) benzoate within a silicone oil as an inert liquid. To characterize the molecular arrangements within the nematoids, we present the microinterferometric measurements of the refractive index distribution within the fibers and its changes at the phase transitions.</p> <div class="credits"> <p class="dwt_author">Adamczyk, Antoni</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/61279217"> <span id="translatedtitle">Heatup of the TMI2 lower head during <span class="hlt">core</span> relocation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">An analysis has been carried out to assess the potential of a <span class="hlt">melting</span> attack upon the reactor vessel lower head and incore instrument nozzle penetration weldments during the TMI <span class="hlt">core</span> relocation event at 224 minutes. Calculations were performed to determine the potential for molten corium to undergo breakup into droplets which freeze and form a debris bed versus impinging upon</p> <div class="credits"> <p class="dwt_author">S. K. Wang; J. J. Sienicki; B. W. Spencer</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/57621835"> <span id="translatedtitle">Thermal-Hydraulics in Uncovered <span class="hlt">Core</span> of Light Water Reactor in Severe <span class="hlt">Core</span> Damage Accident, (IV)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Analysis of the TMI-2 <span class="hlt">core</span> damage behavior has been performed with the SEFDAN code. The scope of the analysis is by the time of restarting the reactor coolant pump RCP-2B at 2 h 54 min into the accident. The analysis indicates that fuel temperature would have reached the <span class="hlt">melting</span> point of UO2 in the upper-most part of the most central</p> <div class="credits"> <p class="dwt_author">Fumiya TANABE; Tohru SUDA</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" 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id="NextPageLink" onclick='return showDiv("page_21");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">381</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60713036"> <span id="translatedtitle">Supplementary documentation for an Environmental Impact Statement regarding the Pantex Plant: radiological consequences of immediate inhalation of plutonium dispersed by <span class="hlt">postulated</span> accidents</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This report documents work performed in support of preparation of an Environmental Impact Statement (EIS) regarding the Department of Energy's (DOE) Pantex Plant near Amarillo, Texas. It describes methods used to estimate potential health consequences offsite resulting from inhalation of plutonium dispersed by each of several <span class="hlt">postulated</span> accidents. The primary topic of this report is the delayed health effects of</p> <div class="credits"> <p class="dwt_author">J. C. Elder; R. H. Olsher; J. M. Graf</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.V53G..07L"> <span id="translatedtitle"><span class="hlt">Melting</span> phase relations in the MgO-MgSiO3 system between 16 and 26 GPa: Implications for <span class="hlt">melting</span> in Earth's deep interior</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Geochemical and geophysical questions relating to the formation and crystallisation of a global Hadean magma ocean, and present day <span class="hlt">melting</span> at the <span class="hlt">core</span>-mantle boundary (CMB), require knowledge of <span class="hlt">melting</span> temperatures of mantle or bulk Earth compositions at mid- or lower mantle pressures. However, a number of experimental problems complicate precise determination of solidus and liquidus phase relations and temperatures for bulk silicate earth compositions at these pressures. These problems are mainly due to the presence of thermal gradients in high pressure experiments. Here, we present high quality <span class="hlt">melting</span> experiments in the system MgO-MgSiO3 to study the eutectic <span class="hlt">melt</span> composition and phase relations between 16 and 26 GPa using a mutlianvil apparatus. By employing a multi-chamber capsule design, several different starting compositions could be run at a single pressure and temperature and internally consistent phase relations and liquidus compositions were obtained. Additional experiments were carried out to determine the effect of FeO on <span class="hlt">melting</span> relations and temperatures. A simple thermodynamic model is developed to describe the observed <span class="hlt">melting</span> phase relations and eutectic compositions in the MgO-MgSiO3 binary. The model is based on equations of states from the literature to describe <span class="hlt">melting</span> curves of end-members and a simple symmetric liquid mixing model. It is shown that <span class="hlt">melting</span> relations of a natural peridotite composition at high pressure can be well described on the basis of the simple binary, particularly once the effects of FeO on phase relations and <span class="hlt">melting</span> temperatures are considered. The thermodynamic model, extrapolated to 140 GPa, predicts that the eutectic composition becomes richer in MgO up to about 80 GPa, where it becomes near constant with pressure and has a Mg/Si ratio close to that of a peridotite composition. By applying a correction to account for the effect of FeO on the <span class="hlt">melting</span> temperatures, the model predicts that the solidus and liquids for a peridotitic composition are never more than 250 K apart. The results can be used to examine a partial <span class="hlt">melt</span> origin for the existence of localised zones with ultra low shear wave velocities (ULVZ) at the CMB. The solidus temperature of peridotitic mantle at the CMB is estimated to be 4400 K, which would require temperatures at the CMB to be at the very top end of the estimated range for <span class="hlt">melting</span> to occur. The proximity of the solidus and liquidus temperature implies that large <span class="hlt">melt</span> fractions could form over small depth intervals as a result of relatively small increases in either temperature or FeO content. This is consistent with a seismically sharp transition in the upper boundary of ULVZ. Given the high temperatures required to <span class="hlt">melt</span> peridotite at the CMB, a partial <span class="hlt">melt</span> origin due to raised FeO contents seems more likely. A further application of the data concerns the crystallisation of a magma ocean during early stages of the Earth. The thermodynamic model allows isentropes of a model magma ocean to be calculated, which can be used to estimate depth intervals between the onset of crystallisation and complete solidification as well as liquid fractions in between. Such data may be useful for a more detailed understanding of magma ocean dynamics or the kinetics of element partitioning between <span class="hlt">core</span>-forming liquids and the silicate Earth.</p> <div class="credits"> <p class="dwt_author">Liebske, C.; Frost, D. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFM.T52C..06A"> <span id="translatedtitle">Modelling the Composition of <span class="hlt">Melts</span> Formed During Continental Breakup of the North Atlantic</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have developed a generic dynamic model of extension of the lithosphere. Major element composition and volume of <span class="hlt">melt</span> generated can be predicted from initial extension to steady state seafloor spreading. Stokes equations for non-Newtonian flow are solved, where mantle <span class="hlt">melts</span> by decompression. Strengthening of the mantle due to dehydration as <span class="hlt">melting</span> progresses is included. Composition is then empirically related to depletion. Using a fractional crystallisation algorithm, the predicted primitive <span class="hlt">melt</span> composition was compared with mean North Atlantic mid-ocean ridge basalt (MORB). At steady state, we predict a major element composition that is within the variation in the mean of North Atlantic MORB for half spreading rates from 10 to 20 mm yr-1 and mantle potential temperatures of 1275 to 1350 °C. We then apply the model to the Southeast Greenland margin, which has extensive coverage of seismic and ODP <span class="hlt">core</span> data. An initial pulse of magmatism on rifting rapidly decayed to leave oceanic crustal thickness of 6 to 7 km. This pattern of <span class="hlt">melt</span> production can be recreated by introducing a hot layer of asthenosphere beneath the continental lithosphere within the initial condition. The hot layer is convected through the <span class="hlt">melt</span> region giving a pulse of high magnesian (peak of 18.44 %) and low silica <span class="hlt">melt</span> (trough of 46.99 %) during the early rifting process. These results are very encouraging as most primitive <span class="hlt">melts</span> from the Southeast Greenland margin are picritic. Fractional crystallisation of our primitive <span class="hlt">melt</span> shows a good agreement with slightly altered basalts from the seaward dipping reflector series off Southeast Greenland. These preliminary results lead us to believe that the style of rifting can be well constrained by compositional variations.</p> <div class="credits"> <p class="dwt_author">Armitage, J. J.; Henstock, T. J.; Minshull, T. A.; Hopper, J. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008E%26PSL.269..248A"> <span id="translatedtitle">Modelling the composition of <span class="hlt">melts</span> formed during continental breakup of the Southeast Greenland margin</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have developed a generic dynamic model of extension of the lithosphere, which predicts major element composition and volume of <span class="hlt">melt</span> generated from initial extension to steady state seafloor spreading. Stokes equations for non-Newtonian flow are solved and the mantle <span class="hlt">melts</span> by decompression. Strengthening of the mantle due to dehydration as <span class="hlt">melting</span> progresses is included. The composition is then empirically related to depletion. Using a crystallisation algorithm, the predicted primary <span class="hlt">melt</span> composition was compared with mean North Atlantic mid-ocean ridge basalt (MORB). At steady state, using half spreading rates from 10 to 20 mm yr - 1 and mantle potential temperatures of 1300 to 1325 °C we predict a major element composition that is within the variation in the mean of North Atlantic MORB. This model is applied to the Southeast Greenland margin, which has extensive coverage of seismic and ODP <span class="hlt">core</span> data. These data have been interpreted to indicate an initial pulse of magmatism on rifting that rapidly decayed to leave oceanic crustal thickness of 8 to 11 km. This pattern of <span class="hlt">melt</span> production can be recreated by introducing an initial hot layer of asthenosphere beneath the continental lithosphere and by having a period of fast spreading during early opening. The hot layer was convected through the <span class="hlt">melt</span> region giving a pulse of high magnesian and low silica <span class="hlt">melt</span> during the early rifting process. The predicted major element composition of primary <span class="hlt">melts</span> generated are in close agreement with primary <span class="hlt">melts</span> from the Southeast Greenland margin. The observed variations in major element composition are reproduced without a mantle source composition anomaly.</p> <div class="credits"> <p class="dwt_author">Armitage, John J.; Henstock, Timothy J.; Minshull, Timothy A.; Hopper, John R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21160790"> <span id="translatedtitle">Experiments on in-vessel <span class="hlt">melt</span> coolability in the EC-FOREVER program</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This paper reports the results from the experiments conducted on the coolability of corium <span class="hlt">melt</span> during a severe accident scenario when the bottom head is full of the <span class="hlt">core</span> <span class="hlt">melt</span>, undergoing natural circulation. These experiments are part of the EC-FOREVER Program in which vessel failure experiments have also been performed. The experiments are performed in a 1/10. scale vessel ({approx_equal} 400 mm dia. and 15 mm wall thickness) and the oxidic <span class="hlt">melt</span> employed is the mixture CaO + B{sub 2}O{sub 3} at {approx_equal} 1400 K, representing the corium <span class="hlt">melt</span> mixture of UO{sub 2} + ZrO{sub 2}. The experiments employed an initial phase, during which uniform volumetric heating of the <span class="hlt">melt</span> was provided and the vessel was pressurized to {approx_equal} 25 bar, for several hours, to generate maximum creep deformation of {approx_equal} 5%; in order to provide the conditions for the formation of a gap between the <span class="hlt">melt</span>-pool crust and the bottom head wall. After this phase, the vessel was flooded with water. Data was obtained on the vessel and the <span class="hlt">melt</span> pool temperatures in one of the EC-FOREVER experiments reported here. In the second experiment, additional data was obtained on the steam flow rate and the heat transfer to the water, at the upper face of the <span class="hlt">melt</span> pool, as a function of time. It was found that the gap cooling mechanism was not effective in reducing the vessel wall temperatures after water flooding. Post test examinations revealed that the water ingression extended to the depth of only {approx_equal} 60 mm in the <span class="hlt">melt</span> pool. (authors)</p> <div class="credits"> <p class="dwt_author">Sehgal, B.R.; Giri, A.; Chikkanagoudar, U.; Karbojian, A. [Division of nuclear power safety (NPS), Royal Institute OF Technology (KTH), 33 A Drottning Kristinas VaeG, 10044 Stockholm (Sweden)</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009CoMP..158..703R"> <span id="translatedtitle">Protracted fluid-induced <span class="hlt">melting</span> during Barrovian metamorphism in the Central Alps</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The timing and dynamics of fluid-induced <span class="hlt">melting</span> in the typical Barrovian sequence of the Central Alps has been investigated using zircon chronology and trace element composition. Multiple zircon domains in leucosomes and country rocks yield U-Pb ages spanning from ~32 to 22 Ma. The zircon formed during Alpine <span class="hlt">melting</span> can be distinguished from the inherited and detrital <span class="hlt">cores</span> on the basis of their age, Th/U (<0.1) and trace element composition. Ti-in-zircon thermometry indicates crystallization temperatures around 620-700°C. Their composition allows discriminating between (1) zircon formation in the presence of early garnet, (2) zircon in equilibrium with abundant L-MREE-rich accessory phases (allanite, titanite and apatite) typical of metatonalites, and (3) zircon formed during <span class="hlt">melting</span> of metasediments in feldspar-dominated assemblages. The distribution of zircon overgrowths and ages indicate that repeated <span class="hlt">melting</span> events occurred within a single Barrovian metamorphic cycle at roughly constant temperature; that in the country rocks zircon formation was limited to the initial stages of <span class="hlt">melting</span>, whereas further <span class="hlt">melting</span> concentrated in the segregated leucosomes; that <span class="hlt">melting</span> occurred at different times in samples a few meters apart because of the local rock composition and localized influx of the fluids; and that leucosomes were repeatedly <span class="hlt">melted</span> when fluids became available. The geochronological data force a revision of the temperature-time path of the migmatite belt in the Central Alps. Protracted <span class="hlt">melting</span> over 10 My followed the fast exhumation of Alpine eclogites contained within the same region and preceded fast cooling in the order of 100°C/Ma to upper crustal levels.</p> <div class="credits"> <p class="dwt_author">Rubatto, Daniela; Hermann, Jörg; Berger, Alfons; Engi, Martin</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013PhDT.......151M"> <span id="translatedtitle">Glass-clad semiconductor <span class="hlt">core</span> optical fibers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Glass-clad optical fibers comprising a crystalline semiconductor <span class="hlt">core</span> have garnered considerable recent attention for their potential utility as novel waveguides for applications in nonlinear optics, sensing, power delivery, and biomedicine. As research into these fibers has progressed, it has become evident that excessive losses are limiting performance and so greater understanding of the underlying materials science, coupled with advances in fiber processing, is needed. More specifically, the semiconductor <span class="hlt">core</span> fibers possess three performance-limiting characteristics that need to be addressed: (a) thermal expansion mismatches between crystalline <span class="hlt">core</span> and glass cladding that lead to cracks, (b) the precipitation of oxide species in the <span class="hlt">core</span> upon fiber cooling, which results from partial dissolution of the cladding glass by the <span class="hlt">core</span> <span class="hlt">melt</span>, and (c) polycrystallinity; all of which lead to scattering and increased transmission losses. This dissertation systematically studies each of these effects and develops both a fundamental scientific understanding of and practical engineering methods for reducing their impact. With respect to the thermal expansion mismatch and, in part, the dissolution of oxides, for the first time to our knowledge, oxide and non-oxide glass compositions are developed for a series of semiconductor <span class="hlt">cores</span> based on two main design criteria: (1) matching the thermal expansion coefficient between semiconductor <span class="hlt">core</span> and glass cladding to minimize cracking and (2) matching the viscosity-temperature dependences, such that the cladding glass draws into fiber at a temperature slightly above the <span class="hlt">melting</span> point of the semiconductor in order to minimize dissolution and improve the fiber draw process. The x[Na 2O:Al2O3] + (100 - 2x)SiO2 glass compositional family was selected due to the ability to tailor the glass properties to match the aforementioned targets through slight variations in composition and adjusting the ratios of bridging and non-bridging oxygen; experimental results show a decrease in fiber <span class="hlt">core</span> oxygen content in the fibers drawn with the tailored glass composition. In a further attempt to reduce the presence of oxide species in the <span class="hlt">core</span>, a reactive molten <span class="hlt">core</span> approach to semiconductor optical fibers are developed. Specifically, the addition of silicon carbide (SiC) into a silicon (Si) <span class="hlt">core</span> provides an <italic>in-situ</italic> reactive getter of oxygen during the draw process to achieve oxygen-free silicon optical fibers. Elemental analysis and x-ray diffraction of fibers drawn using this reactive chemistry approach show negligible oxygen concentration in the highly crystalline silicon <span class="hlt">core</span>, a significant departure from the nearly 18 atom percent oxygen in previous fibers. Scattering of light out of the <span class="hlt">core</span> is shown qualitatively to have been reduced in the process. The role of the cross-sectional geometry on the resultant <span class="hlt">core</span> crystallography with respect to the fiber axis is explored in a continued effort to better understand the nature of the crystal formation and structural properties in these semiconductor <span class="hlt">core</span> optical fibers. A square cross-sectional geometry was explored to determine if <span class="hlt">core</span> non-circularity can enhance or promote single crystallinity, as the semiconductors studied have a preference to form cubic crystals. Resultant crystallography of the non-circular <span class="hlt">core</span> showed a significant improvement in maintaining a preferred crystallographic orientation, with the square <span class="hlt">core</span> fibers exhibiting a 90% preference for the < 1 1 0 > family of directions occurring closest to the longitudinal direction of the fiber. The ability to orient the crystallography with respect to the fiber axis could be of great value to future nonlinear optical fiber-based devices. In summary, this dissertation begins to elucidate some of the microstructural features, not present in conventional glass optical fibers, which could be important for future low-loss single crystalline semiconductor optical fibers. Additionally, this dissertation offers novel insight into the various aspects of mate</p> <div class="credits"> <p class="dwt_author">Morris, Stephanie Lynn</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFM.T23A2242L"> <span id="translatedtitle"><span class="hlt">Melt</span> microstructures and U-Pb SHRIMP zircon ages of tonalitic migmatites, Daeijak Island, South Korea: A contrast in <span class="hlt">melt</span> distribution during the Triassic anatexis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The spatial distribution of <span class="hlt">melt</span> in tonalitic migmatites of Daeijak Island, South Korea, was investigated at the grain scale in order to decipher the relationship between <span class="hlt">melt</span> distribution and multiple stages of zircon growth, dated using a sensitive high-resolution ion microprobe (SHRIMP). The <span class="hlt">melt</span> distribution was inferred from various microstructures occurring commonly in leucosomes and rarely in melanosomes. Three types of leucosomes were recognized on the basis of former-<span class="hlt">melt</span> distribution patterns, grain size distributions, and matrix mineral fabrics: (1) layer-parallel leucosomes (L1) characterized by randomly-distributed thin films or narrow pools of K-feldspar, in association with matrix minerals such as plagioclase and quartz showing lobate boundary and weak shape-preferred orientation; (2) shear band leucosomes (L2) marked by wide <span class="hlt">melt</span> pools of K-feldspar coexisting with randomly-oriented plagioclase, quartz and rare hornblende; and (3) interboudin leucosomes (L3) characterized by magmatic texture of euhedral plagioclase surrounded by interstitial quartz. The grain size of leucosomes increases from L1 through L2 to L3, suggesting a different time-scale of <span class="hlt">melt</span> crystallization. Zircon grains of L1 show oscillatory-zoned <span class="hlt">cores</span> and wide overgrowth rims, which have been dated at ca. 2580 Ma and 2510 Ma, respectively [1]. Very thin rims are rarely present but could not be dated. On the other hand, in L3, xenocrystic <span class="hlt">cores</span> of zircon are mantled by euhedral magmatic rims which are newly grown in the presence of <span class="hlt">melt</span> and range in size up to ca. 0.02 mm. These <span class="hlt">cores</span> show the same age pattern as the L1 zircon, but the rims were dated at 227 ± 5 Ma, suggesting an anatectic episode at Triassic. Thus, zircons of L1 and L3 apparently differ in their response to <span class="hlt">melt</span>-related processes. We speculate that the Triassic deformation has modified L1 at magmatic to sub-solidus conditions, but L2 and L3 were in a relatively static state owing to strain partitioning between leucosome and melanosome. In conclusion, the variations in mineral paragenesis, grain size, and zircon overgrowth pattern in leucosomes are mainly governed by deformation-related microstructures, including pore size and spatial distribution of fertile domains. [1] Cho et al., Geosci J, 12:1 (2008).</p> <div class="credits"> <p class="dwt_author">Lee, Y.; Cho, M.; Kim, Y.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..16.5975W"> <span id="translatedtitle">Probing depth dependencies of <span class="hlt">melt</span> emplacement on time dependent quantities in a continental rift scenario with <span class="hlt">melting</span> and <span class="hlt">melt</span> extraction</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Since some years seismological observations provide increasing evidence of a discontinuity near the mid of older mantle lithosphere. Explanation may be a <span class="hlt">melt</span> infiltration front (MIF) as upper margin of an evolving network of veins. These are formed by crystallized <span class="hlt">melt</span> supplied by episodic <span class="hlt">melting</span> events in the asthenosphere. To test this concept geodynamically we performed numerical modelling applying <span class="hlt">melting</span>, extraction of <span class="hlt">melt</span> and emplacement in a viscous matrix. Thereupon, we were faced to the problem defining an intrusion level for the <span class="hlt">melt</span>. Findings of prior studies led to the need of movable, process dependent boundaries of the emplacement zone additionally making the process probably more self-consistent. Here we present a preliminary study exploring several empirical attempts to relate time dependent states to an upward moving boundary for intrusion. Modeled physics is based on thermo-mechanics of visco-plastic flow. The equations of conservation of mass, momentum and energy are solved for a multi component (crust-mantle) and two phase (<span class="hlt">melt</span>-matrix) system. Rheology is temperature-, pressure-, and stress-dependent. In consideration of depletion and enrichment <span class="hlt">melting</span> and solidification are controlled by a simplified linear binary solid solution model. The Compaction Boussinesq Approximation and the high Prandtl number approximation are used, elasticity is neglected and geometry is restricted to 2D. Approximation is done with the Finite Difference Method with markers in an Eulerian formulation (FDCON). Model guiding scenario is a extending thick lithosphere associated to by updoming asthenosphere probably additionally heated by a plume nearby. As the P-T conditions in the asthenosphere are near the solidus caused changes may increase <span class="hlt">melting</span> and generate partial <span class="hlt">melt</span>. Against conventional expectations on permeability at lithosphere-asthenosphere boundary (LAB) depth a fast <span class="hlt">melt</span> transport into and sometimes through the lithosphere often is observed. The intruded or infiltrated, solidified <span class="hlt">melt</span> modifies composition and physical properties of the affected lithosphere. Above a critical fraction limit <span class="hlt">melt</span> is extracted and intruded above. The uppermost front of extraction, petrophysically seen as LAB, defines the lower boundary of the emplacement zone. The upper boundary is related to various quantities, particularly temperature, <span class="hlt">melt</span> curve, <span class="hlt">melt</span> front, stress, dynamic pressure and more. Changes of intrusion level imply different convection patterns affecting intensity of erosion of the lower lithosphere, doming rate of asthenosphere and <span class="hlt">melt</span>-induced weakening. Thus, the shape and location and therefore its dependence influences intensively the dynamics of rifting.</p> <div class="credits"> <p class="dwt_author">Wallner, Herbert; Schmeling, Harro</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003EAEJA.....3316N"> <span id="translatedtitle">A one-dimensional snow-firn layer model for glaciers subjected to seasonal <span class="hlt">melting</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Geochemical analysis of the ice <span class="hlt">cores</span> provides valuable information about past climate change. The correct interpretation of such data demands knowledge of an annual layer structure formation process. A one-dimensional model for the glacier snow-firn layer subjected to <span class="hlt">melting</span> is presented here. The <span class="hlt">melting</span> occurs due to the warm summer temperatures and intensive sun radiation. As a result the <span class="hlt">melt</span> water penetrates into the deeper layers and re-freezes there. Moreover, snow is subjected to the creep resulting in its compaction. The model allows for investigating the snow layer composition and density changes at various scenarios of climate change. Our model takes into account the snow-atmosphere interaction (the snow surface temperature is defined from the surface heat budget and depends on the atmosphere parameters such as a wind speed, specific humidity, atmosphere pressure and temperature); albedo feedback (the <span class="hlt">melted</span> water decreases the snow albedo and intensifies <span class="hlt">melting</span>). The model was applied to the Grigoriev Ice Cap (41.979^o N; 77.916^o E; 4625 m), where two long snow-ice <span class="hlt">cores</span> were extracted during summer of 1990 and 2001 years. The comparison of the calculated and measured annual layers structures allowed for formulating the effective heat source parameters connected with latent heat releasing due to water freezing. These parameters are needed for reconstruction of the past climate and prediction of the glacier evolution.</p> <div class="credits"> <p class="dwt_author">Nagornov, O.; Sergienko, O.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10136350"> <span id="translatedtitle">Fragmentation and quench behavior of corium <span class="hlt">melt</span> streams in water</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The interaction of molten <span class="hlt">core</span> materials with water has been investigated for the pour stream mixing mode. This interaction plays a crucial role during the later stages of in-vessel <span class="hlt">core</span> <span class="hlt">melt</span> progression inside a light water reactor such as during the TMI-2 accident. The key issues which arise during the molten <span class="hlt">core</span> relocation include: (i) the thermal attack and possible damage to the RPV lower head from the impinging molten fuel stream and/or the debris bed, (ii) the molten fuel relocation pathways including the effects of redistribution due to <span class="hlt">core</span> support structure and the reactor lower internals, (iii) the quench rate of the molten fuel through the water in the lower plenum, (iv) the steam generation and hydrogen generation during the interaction, (v) the transient pressurization of the primary system, and (vi) the possibility of a steam explosion. In order to understand these issues, a series of six experiments (designated CCM-1 through {minus}6) was performed in which molten corium passed through a deep pool of water in a long, slender pour stream mode. Results discussed include the transient temperatures and pressures, the rate and magnitude of steam/hydrogen generation, and the posttest debris characteristics.</p> <div class="credits"> <p class="dwt_author">Spencer, B.W.; Wang, K.; Blomquist, C.A.; McUmber, L.M. [Argonne National Lab., IL (United States); Schneider, J.P. [Illinois Univ., Urbana, IL (United States). Dept. of Nuclear Engineering</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JHEP...04..099I"> <span id="translatedtitle">Dynamical meson <span class="hlt">melting</span> in holography</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We discuss mesons in thermalizing gluon backgrounds in the = 2 super-symmetric QCD using the gravity dual. We numerically compute the dynamics of a probe D7-brane in the Vaidya-AdS geometry that corresponds to a D3-brane background thermalizing from zero to finite temperatures by energy injection. In static backgrounds, it has been known that there are two kinds of brane embeddings where the brane intersects the black hole or not. They correspond to the phases with <span class="hlt">melted</span> or stable mesons. In our dynamical setup, we obtain three cases depending on final temperatures and injection time scales. The brane stays outside of the black hole horizon when the final temperature is low, while it intersects the horizon and settles down to the static equilibrium state when the final temperature is high. Between these two cases, we find the overeager case where the brane dynamically intersects the horizon although the final temperature is not high enough for a static brane to intersect the horizon. The interpretation of this phenomenon in the dual field theory is meson <span class="hlt">melting</span> due to non-thermal effects caused by rapid energy injection. In addition, we comment on the late time evolution of the brane and a possibility of its reconnection.</p> <div class="credits"> <p class="dwt_author">Ishii, Takaaki; Kinoshita, Shunichiro; Murata, Keiju; Tanahashi, Norihiro</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=MSFC-0300192&hterms=palladium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dpalladium"> <span id="translatedtitle"><span class="hlt">Melting</span> a Sample within TEMPUS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">One of the final runs of the TEMPUS experiment shows heating of a sample on STS-94, July 15, 1997, MET:14/11:01 (approximate) and the flows on the surface. At the point this image was taken, the sample was in the process of <span class="hlt">melting</span>. The surface of the sample is begirning to flow, looking like the motion of plate tectonics on the surface of a planet. During this mission, TEMPUS was able to run than 120 <span class="hlt">melting</span> cycles with zirconium, with a maximum temperature of 2,000 degrees C, and was able to undercool by 340 degrees -- the highest temperature and largest undercooling ever achieved in space. The TEMPUS investigators also have provided the first measurements of viscosity of palladium-silicon alloys in the undercooled liquid alloy which are not possible on Earth. TEMPUS (stands for Tiegelfreies Elektromagnetisches Prozessiere unter Schwerelosigkeit (containerless electromagnetic processing under weightlessness). It was developed by the German Space Agency (DARA) for flight aboard Spacelab. The DARA project scientist was Igon Egry. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). DARA and NASA are exploring the possibility of flying an advanced version of TEMPUS on the International Space Station.(176KB JPEG, 1350 x 1516 pixels; downlinked video, higher quality not available) The MPG from which this composite was made is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300193.html.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006Geo....34..305W"> <span id="translatedtitle"><span class="hlt">Melt</span> segregation structures in granitic plutons</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">When <span class="hlt">melt</span> fraction increases beyond a critical value, migmatites behave as magmas. Conversely, when <span class="hlt">melt</span> fraction decreases, crystallizing magmas form solid-framework mushes and behave as solids. The richness in preserved mesoscopic <span class="hlt">melt</span> segregation structures in migmatites is not matched by <span class="hlt">melt</span> segregation structures in granitic bodies. This paper identifies <span class="hlt">melt</span> segregation structures in granites and compares them to structures in migmatites. The rarity of segregation structures in granites is a consequence of the solid-framework mush allowing for cryptic <span class="hlt">melt</span> extraction from its pores, the relatively short duration of solidification of the mush, and the fragile nature of the solid framework. Identifying segregation features in granitoids at outcrop scale provides the basis for understanding the physical processes that lead to chemical and mineralogical differentiation in granitic magmas.</p> <div class="credits"> <p class="dwt_author">Weinberg, Roberto F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008JPhCS.114a2031J"> <span id="translatedtitle">450 kW plasma <span class="hlt">melting</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Plasma <span class="hlt">melting</span> technology can be used to meet the scrap recycle needs of reactive metals, superalloys and refractory materials such as titanium, zirconium and uranium alloys. Fabrication involving these reactive metals, share the common problem of generating a large amount of scrap where both low and high density inclusions become highly prevalent. Plasma <span class="hlt">melting</span> technology can be used for re-<span class="hlt">melting</span>, refining and production of premium grade metal ingot. 450kW multi-torch plasma <span class="hlt">melting</span> furnace is developed and commissioned by Laser & Plasma Technology Division for the re-<span class="hlt">melting</span> and refining of metals and scraps under controlled environment. This paper presents the vacuum system design for 450 kW plasma <span class="hlt">melting</span> furnace. The efficacy of vacuum system in cold condition is also tested and the results are included in the paper. The vacuum feed through design for the plasma torch handling mechanism is also discussed.</p> <div class="credits"> <p class="dwt_author">Jha, M. N.; Sahashrabuddhe, S. N.; Murthy, P. S. S.; Bapat, A. V.; Das, A. K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17095697"> <span id="translatedtitle">Transcrystalline <span class="hlt">melt</span> migration and Earth's mantle.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Plate tectonics and volcanism involve the formation, migration, and interaction of magma and gas. Experiments show that <span class="hlt">melt</span> inclusions subjected to a thermal gradient migrate through olivine crystals, under the kinetic control of crystal-<span class="hlt">melt</span> interface mechanisms. Exsolved gas bubbles remain fixed and eventually separate from the <span class="hlt">melt</span>. Scaled to thermal gradients in Earth's mantle and geological times, our results account for the grain-scale segregation of primitive <span class="hlt">melts</span>, reinterpret CO2-rich fluid inclusions as escaped from <span class="hlt">melt</span>, and question the existence of a free, deeply percolating fluid phase. <span class="hlt">Melt</span> migration experiments also allow us to quantify crystal growth kinetics at very low undercoolings in conditions appropriate to many natural systems. PMID:17095697</p> <div class="credits"> <p class="dwt_author">Schiano, Pierre; Provost, Ariel; Clocchiatti, Roberto; Faure, François</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-11-10</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUSM.V31A..01L"> <span id="translatedtitle">Solid-liquid boundaries in iron-rich alloys and the age of the Earth's inner <span class="hlt">core</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Melting</span> and solidification cause major chemical differentiation in the Earth. As the Earth cools, the liquid <span class="hlt">core</span> solidifies from the center and the inner <span class="hlt">core</span> grows at the expense of the outer <span class="hlt">core</span>. The timing of the onset of <span class="hlt">core</span> solidification remains poorly constrained. Labrosse et al. (2001) estimated the age of the Earth's inner <span class="hlt">core</span> based on energy budget considerations. In their analysis, the latent heat and gravitational energy are calculated according to dislocation <span class="hlt">melting</span> theory. We have conducted <span class="hlt">melting</span> experiments on pure iron and an iron-sulfur alloy containing 15 at.% sulfur, in order to determine the effect of pressure on the Clapeyron slopes of the solid-liquid boundaries. Our results allow a critical examination of the energy estimates, hence the age of the inner <span class="hlt">core</span>. The implications for the budget of radioactive elements will be discussed.</p> <div class="credits"> <p class="dwt_author">Li, J.; Chen, B.; Gao, L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">398</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19880009842&hterms=charles+darwin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcharles%2Bdarwin"> <span id="translatedtitle"><span class="hlt">Core-core</span> and <span class="hlt">core</span>-valence correlation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The effect of (1s) <span class="hlt">core</span> correlation on properties and energy separations was analyzed using full configuration-interaction (FCI) calculations. The Be 1 S - 1 P, the C 3 P - 5 S and CH+ 1 Sigma + or - 1 Pi separations, and CH+ spectroscopic constants, dipole moment and 1 Sigma + - 1 Pi transition dipole moment were studied. The results of the FCI calculations are compared to those obtained using approximate methods. In addition, the generation of atomic natural orbital (ANO) basis sets, as a method for contracting a primitive basis set for both valence and <span class="hlt">core</span> correlation, is discussed. When both <span class="hlt">core-core</span> and <span class="hlt">core</span>-valence correlation are included in the calculation, no suitable truncated CI approach consistently reproduces the FCI, and contraction of the basis set is very difficult. If the (nearly constant) <span class="hlt">core-core</span> correlation is eliminated, and only the <span class="hlt">core</span>-valence correlation is included, CASSCF/MRCI approached reproduce the FCI results and basis set contraction is significantly easier.</p> <div class="credits"> <p class="dwt_author">Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">399</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20100009796&hterms=chondrites&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dchondrites"> <span id="translatedtitle">Low-Degree Partial <span class="hlt">Melting</span> Experiments of CR and H Chondrite Compositions: Implications for Asteroidal Magmatism Recorded in GRA 06128 and GRA 06129 T</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Studies of differentiated meteorites have revealed a diversity of differentiation processes on their parental asteroids; these differentiation mechanisms range from whole-scale <span class="hlt">melting</span> to partial <span class="hlt">melting</span> without the <span class="hlt">core</span> formation [e.g., 1]. Recently discovered paired achondrites GRA 06128 and GRA 06129 (hereafter referred to as GRA) represent unique asteroidal magmatic processes. These meteorites are characterized by high abundances of sodic plagioclase and alkali-rich whole-rock compositions, implying that they could originate from a low-degree partial <span class="hlt">melt</span> from a volatile-rich oxidized asteroid [e.g., 2, 3, 4]. These conditions are consistent with the high abundances of highly siderophile elements, suggesting that their parent asteroid did not segregate a metallic <span class="hlt">core</span> [2]. In this study, we test the hypothesis that low-degree partial <span class="hlt">melts</span> of chondritic precursors under oxidizing conditions can explain the whole-rock and mineral chemistry of GRA based on <span class="hlt">melting</span> experiments of synthesized CR- and H-chondrite compositions.</p> <div class="credits"> <p class="dwt_author">Usui, T.; Jones, John H.; Mittlefehldt, D. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">400</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60574628"> <span id="translatedtitle">Numerical Simulation of Two-Phase Flow in Severely Damaged <span class="hlt">Core</span> Geometries</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In the event of a severe accident in a nuclear reactor, the oxidation, dissolution and collapse of fuel rods is likely to change dramatically the geometry of the <span class="hlt">core</span>. A large part of the <span class="hlt">core</span> would be damaged and would look like porous medium made of randomly distributed pellet fragments, broken claddings and relocated <span class="hlt">melts</span>. Such a complex medium must</p> <div class="credits"> <p class="dwt_author">Phongsan Meekunnasombat; Florian Fichot; Michel Quintard</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="